Author: "Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC" / Topic: 030204 cardiovascular system & hematology - Searchworks@Jio Institute Digital Library Search Results

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80 results on '"Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC"'

1. Left-axis deviation in patients with nonischemic heart failure and left bundle branch block is a purely electrical phenomenon

Author: Michel Haïssaguerre, F. Daniel Ramirez, Romain Eschalier, Hubert Cochet, Peter Huntjens, Saer Abu-Alrub, Samuel Buliard, Hugo Marchand, Pierre Bordachar, Mark Potse, Marc Strik, Sylvain Ploux, CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Washington University in Saint Louis (WUSTL), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), CHU Clermont-Ferrand, This work received financial support from the French Government as part of the 'Investments of the Future' program managed by the National Research Agency (ANR), Grant reference ANR-10-IAHU-04. FDR is supported by a Canadian Institutes of Health Research Banting Postdoctoral Fellowship., ANR-10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Male, medicine.medical_specialty, Heart Ventricles, Bundle-Branch Block, Block, 030204 cardiovascular system & hematology, Cardiac Resynchronization Therapy, Electrocardiography, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Internal medicine, medicine, Electrical mapping, Humans, Cardiac structure, In patient, cardiovascular diseases, 030212 general & internal medicine, Left bundle branch, ComputingMilieux_MISCELLANEOUS, Aged, Heart Failure, medicine.diagnostic_test, Left bundle branch block, Cardiac electrophysiology, business.industry, Computer modeling, Magnetic resonance imaging, Middle Aged, medicine.disease, Heart failure, cardiovascular system, Cardiology, Left axis deviation, Female, QRS axis, Cardiology and Cardiovascular Medicine, Qrs axis, business, Left-axis deviation, Electromagnetic Phenomena
Abstract: Possible mechanisms of left-axis deviation (LAD) in the setting of left bundle branch block (LBBB) include differences in cardiac electrophysiology, structure, or anatomic axis.The purpose of this study was to clarify the mechanism(s) responsible for LAD in patients with LBBB.Twenty-nine patients with nonischemic cardiomyopathies and LBBB underwent noninvasive electrocardiographic imaging (ECGi), cardiac computed tomography, and magnetic resonance imaging in order to define ventricular electrical activation, characterize cardiac structure, and determine the cardiac anatomic axis.Sixteen patients had a normal QRS axis (NA) (mean axis 8° ± 23°), whereas 13 patients had LAD (mean axis -48° ± 13°; P.001). Total activation times were longer in the LAD group (112 ± 25 ms vs 91 ± 14 ms; P = .01) due to delayed activation of the basal anterolateral region (107 ± 10 ms vs 81 ± 17 ms; P .001). Left ventricular (LV) activation in patients with LAD was from apex to base, in contrast to a circumferential pattern of activation in patients with NA. Apex-to-base delay was longer in the LA group (95 ± 13 ms vs 64 ± 21 ms; P.001) and correlated with QRS frontal axis (RLAD in LBBB appears to be due to electrophysiological abnormalities rather than structural factors or cardiac anatomic axis.
Published: 2021

2. Reconstruction of three-dimensional biventricular activation based on the 12-lead electrocardiogram via patient-specific modelling

Author: Frits W. Prinzen, Giulio Conte, Rolf Krause, Simone Pezzuto, Mark Potse, Maria Luce Caputo, François Regoli, Angelo Auricchio, Francesco Maffessanti, Fysiologie, RS: Carim - H06 Electro mechanics, Clinical sciences, Center for Computational Medicine in Cardiology (CCMC), Università della Svizzera italiana = University of Italian Switzerland (USI), Cardiovascular Research Institute Maastricht (CARIM), Maastricht University [Maastricht], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Cardiocentro Ticino [Lugano], Universität Zürich [Zürich] = University of Zurich (UZH), Theo Rossi di Montelera Foundation (Lausanne, Switzerland), Metis Foundation Sergio Mantegazza (Lugano, Switzerland), Fidinam Foundation (Lugano, Swizerland), Swiss Heart Foundation (Bern, Switzerland), SNSF project 32003B_165802 (Bern, Switzerland), Horten Foundation (Castelrotto, Switzerland), and CSCS—Swiss National Supercomputing Centre production grant s778 (Lugano, Switzerland)., University of Zurich, Pezzuto, Simone, Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)
Subjects: CARDIAC ELECTROPHYSIOLOGY, medicine.medical_specialty, Patient-specific modelling, Heart Ventricles, 0206 medical engineering, 12 lead electrocardiogram, 610 Medicine & health, 02 engineering and technology, 030204 cardiovascular system & hematology, Heart Ventricles/diagnostic imaging, Techincal Issues, 11171 Cardiocentro Ticino, 2705 Cardiology and Cardiovascular Medicine, Nerve conduction velocity, VALIDATION, 03 medical and health sciences, QRS complex, Electrocardiography, 2737 Physiology (medical), 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Internal medicine, Eikonal model, medicine, Humans, magnetic resonance imaging, AcademicSubjects/MED00200, cardiovascular diseases, Endocardium, Coronary sinus, medicine.diagnostic_test, Ventricular activation • Three-dimensional activation, business.industry, Cardiac electrophysiology, Body Surface Potential Mapping, Magnetic resonance imaging, 020601 biomedical engineering, Three-dimensional activation, Ventricular activation, Twelve-lead electrocardiogram, Cardiology, cardiovascular system, patient-specific modeling, business, Cardiology and Cardiovascular Medicine
Abstract: Aims Non-invasive imaging of electrical activation requires high-density body surface potential mapping. The nine electrodes of the 12-lead electrocardiogram (ECG) are insufficient for a reliable reconstruction with standard inverse methods. Patient-specific modelling may offer an alternative route to physiologically constraint the reconstruction. The aim of the study was to assess the feasibility of reconstructing the fully 3D electrical activation map of the ventricles from the 12-lead ECG and cardiovascular magnetic resonance (CMR). Methods and results Ventricular activation was estimated by iteratively optimizing the parameters (conduction velocity and sites of earliest activation) of a patient-specific model to fit the simulated to the recorded ECG. Chest and cardiac anatomy of 11 patients (QRS duration 126–180 ms, documented scar in two) were segmented from CMR images. Scar presence was assessed by magnetic resonance (MR) contrast enhancement. Activation sequences were modelled with a physiologically based propagation model and ECGs with lead field theory. Validation was performed by comparing reconstructed activation maps with those acquired by invasive electroanatomical mapping of coronary sinus/veins (CS) and right ventricular (RV) and left ventricular (LV) endocardium. The QRS complex was correctly reproduced by the model (Pearson’s correlation r = 0.923). Reconstructions accurately located the earliest and latest activated LV regions (median barycentre distance 8.2 mm, IQR 8.8 mm). Correlation of simulated with recorded activation time was very good at LV endocardium (r = 0.83) and good at CS (r = 0.68) and RV endocardium (r = 0.58). Conclusion Non-invasive assessment of biventricular 3D activation using the 12-lead ECG and MR imaging is feasible. Potential applications include patient-specific modelling and pre-/per-procedural evaluation of ventricular activation.
Published: 2021

3. Towards the modeling of the Purkinje/myocardium coupled problem: A well-posedness analysis

Author: S. Mani Aouadi, W. Mbarki, Nejib Zemzemi, Université de Tunis El Manar (UTM), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), LIRIMA, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: Discretization, Purkinje fibers, Quantitative Biology::Tissues and Organs, Physics::Medical Physics, 030204 cardiovascular system & hematology, Space (mathematics), Discrete problem, 03 medical and health sciences, 0302 clinical medicine, medicine, Weighted Sobolev spaces, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Uniqueness, [MATH]Mathematics [math], Purkinje/myocardium, 030304 developmental biology, Mathematics, 0303 health sciences, Applied Mathematics, Mathematical analysis, Semi-implicit scheme, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Finite element method, Coupling (electronics), Sobolev space, Computational Mathematics, medicine.anatomical_structure, 2010 MSC: 92B05, 35K55, 35K57, 65N38, Electrical conduction system of the heart, Monodomain/bidomain
Abstract: The Purkinje network is the specialized conduction system in the heart. It ensures the physiological spread of the electrical wave in the ventricles. In this work, in an insulated heart framework, we model the free running Purkinje system, using the monodomain equation. The intra-myocardium part of the Purkinje fiber is coupled to the ventricular tissue using the bidomain equation. The coupling is performed through the extracellular potential. We discretize the problem in time using a semi-implicit scheme. Then, we write a variational formulation of the semi discrete problem in a non standard weighted Sobolev functional spaces. We prove the existence and uniqueness of the solution of the Purkinje/myocardium semi-discretized problem. We discretize in space by the finite element P 1 − L a g r a n g e and conduct some numerical tests showing the anterograde and retrograde propagation of the electrical wave between the tissue and the Purkinje fibers.
Published: 2019

4. Left Atrial Appendage Electrical Isolation Reduces Atrial Fibrillation Recurrences A Simulation Study

Author: Rolf Krause, Sander Verheule, Ali Gharaviri, Ulrich Schotten, Simone Pezzuto, Giulio Conte, Mark Potse, Angelo Auricchio, Center for Computational Medicine in Cardiology (CCMC), Università della Svizzera italiana = University of Italian Switzerland (USI), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Department of Physiology [Maastricht], Maastricht University [Maastricht], Fondazione Cardiocentro Ticino, This work was supported by the Swiss National Supercomputing Centre (CSCS project ID s778), by grants to US from the Netherlands Heart Foundation (CVON2014-09, RACE V), and the EU (ERACoSysMED H2020 ERA-NET). Dr Conte is supported by the Swiss National Foundation (SNF) (Ambizione grant no PZ00P3_180055 / 1)., European Project: 643271,H2020,H2020-HCO-2014,ERACoSysMed(2015), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), University of Zurich, and Clinical sciences
Subjects: medicine.medical_specialty, left atrial appendage, medicine.medical_treatment, 610 Medicine & health, Catheter ablation, 030204 cardiovascular system & hematology, 11171 Cardiocentro Ticino, Heart Conduction System/physiopathology, Electrical isolation, 03 medical and health sciences, 0302 clinical medicine, Left atrial appendage electrical isolation, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Heart Conduction System, Recurrence, Left atrial, Physiology (medical), Internal medicine, Humans, Medicine, Atrial Appendage, Computer Simulation, atrial fibrillation, Atrial Appendage/surgery, Atrial Fibrillation recurrence, ComputingMilieux_MISCELLANEOUS, in-silico study, pulmonary vein isolation, 030304 developmental biology, Appendage, CATHETER ABLATION, 0303 health sciences, business.industry, fibrosis, Atrial fibrillation, medicine.disease, Catheter Ablation/methods, 3. Good health, Atrial Fibrillation/physiopathology, Treatment Outcome, Cardiology, Catheter ablation Fibrosis, Cardiology and Cardiovascular Medicine, business, Arrhythmia
Abstract: Supplemental Digital Content is available in the text.
Published: 2021

5. Shape Analysis of Segmentation Variability

Author: Rob S. MacLeod, Wilson W. Good, Peter M. van Dam, Jess D. Tate, Dana H. Brooks, Nejib Zemzemi, University of Utah, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Utrecht Brain Center [UMC], University Medical Center [Utrecht], Northeastern University [Boston], and This project was supported by the National Institute of General Medical Sciences of the National Institutes of Health under grant numbers P41GM103545, R24GM136986, U24EB029012, U24EB029011, R01AR076120, R01HL135568.
Subjects: business.industry, Computer science, Pattern recognition, Image segmentation, 030204 cardiovascular system & hematology, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, 03 medical and health sciences, 0302 clinical medicine, Ventricular outflow tract, Segmentation, 030212 general & internal medicine, Artificial intelligence, Uncertainty quantification, business, Shape analysis (digital geometry)
Abstract: International audience; Patient-specific cardiac simulation rely on accurate geometric models extracted from medical images. Segmentation of cardiac images is a key, yet possibly error-prone part of patient-specific simulations, e.g., heart propagation models, ECG forward simulation, and ECG Imaging. In this study, we performed shape analysis on multiple segmentations of the same patient to quantify variability. We found that segmentation shape varied most in the basal region of the ventricles and the right ventricular outflow tract in all three structures, which could have significant impact on pipelines that depend on geometric models. The statistical shape-model generated using ShapeWorks provides a pathway to subsequently quantify the impact of the segmentation variability on modeling pipelines with uncertainty quantification.
Published: 2020

6. Feasibility of Whole-Heart Electrophysiological Models With Near-Cellular Resolution

Author: Yves Coudière, Mark Potse, Denis Barthou, Emmanuelle Saillard, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), STatic Optimizations, Runtime Methods (STORM), Laboratoire Bordelais de Recherche en Informatique (LaBRI), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut Polytechnique de Bordeaux (Bordeaux INP), This work was granted access to the HPC resources of TGCC under the allocation 2019gch0409 and allocation 2020-A0070307379 made by GENCI, ANR-18-CE46-0010,Exacard,Simulation exascale de l'électrophysiologie cardiaque pour la recherche sur les arythmies(2018), ANR-10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), ANR-11-EQPX-0030,MUSIC,Plateforme multi-modale d'exploration en cardiologie(2011), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), and Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest
Subjects: Speedup, Computer science, Small number, Explicit method, 030204 cardiovascular system & hematology, Solver, 01 natural sciences, Backward Euler method, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, 03 medical and health sciences, 0302 clinical medicine, Cellular resolution, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Computer cluster, 0103 physical sciences, [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], 010306 general physics, Algorithm, Scaling
Abstract: International audience; Given the opportunity to use a new cluster computer with over a quarter million compute cores we tested the strong and weak scaling of a monodomain reaction-diffusion model of the human ventricles with Ten Tusscher-Panfilov dynamics. Element sizes down to 25 µm and a model size up to 11 billion nodes were tested with both explicit and implicit Euler integration methods. Time steps were 0.01 ms for the implicit method and were resolution-dependent for the explicit method. We found that the weak scaling (increasing model size) was good for both methods. Depending on the model size, strong scaling (speedup at a larger number of cores) was satisfactory for the explicit method, and more limited for the implicit method. The implicit solver was generally slower; only at a resolution of 25 µm and on a relatively small number of cores it was as fast as the explicit solver. We conclude that whole-heart simulations at 25 µm resolution are technically feasible, although not practical yet on currently available systems.
Published: 2020

7. An Improved Iterative Pace-Mapping Algorithm to Detect the Origin of Premature Ventricular Contractions

Author: Michel Haïssaguerre, Andony Arrieula, Mark Potse, Pierre Jaïs, Hubert Cochet, IHU-LIRYC, CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), CHU Bordeaux [Bordeaux], Université de Bordeaux (UB), Institut National de la Santé et de la Recherche Médicale (INSERM), This work was supported by the Région Nouvelle-Aquitaine, grant nr. 2017 – 1R50109 – 00013434, the European Research Council (H2020 grant agreement number 715093, ECSTATIC), and the French National Research Agency, grant references ANR-10-IAHU04-LIRYC and ANR-11-EQPX-0030., ANR-11-EQPX-0030,MUSIC,Plateforme multi-modale d'exploration en cardiologie(2011), ANR-10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), European Project: 715093,H2020,ERC-2016-STG,ECSTATIC(2017), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Arrieula, Andony, Equipements d'excellence - Plateforme multi-modale d'exploration en cardiologie - - MUSIC2011 - ANR-11-EQPX-0030 - EQPX - VALID, Instituts Hospitalo-Universitaires - L'Institut de Rythmologie et modélisation Cardiaque - - LIRYC2010 - ANR-10-IAHU-0004 - IAHU - VALID, Electrostructural Tomography - Towards Multiparametric Imaging of Cardiac Electrical Disorders - ECSTATIC - - H20202017-02-01 - 2022-01-31 - 715093 - VALID, Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, ANR-11-EQPX-0030/11-EQPX-0030,MUSIC,Plateforme multi-modale d'exploration en cardiologie(2011), ANR: 10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), and CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]
Subjects: Fibrillation, medicine.medical_specialty, medicine.diagnostic_test, business.industry, medicine.medical_treatment, Catheter ablation, 030204 cardiovascular system & hematology, Ventricular tachycardia, medicine.disease, Ablation, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, 03 medical and health sciences, QRS complex, Catheter, 0302 clinical medicine, Internal medicine, Ventricular fibrillation, medicine, Cardiology, 030212 general & internal medicine, [INFO.INFO-MO] Computer Science [cs]/Modeling and Simulation, medicine.symptom, business, Electrocardiography
Abstract: International audience; Premature ventricular contraction (PVC) is one of the mechanisms that induce Ventricular Tachycardia (VT) or Ventricular Fibrillation (VF). A way to cure PVC is to ab-late the origin with an endocardial catheter. But it can be difficult, and sometimes impossible, to localize this exit site accurately enough. We propose to accelerate catheter ablation using an automatic method to guide the catheter towards the PVC origin. This method uses the QRS complex integrals of the 8-lead ECGs of the PVC and a sequence of beats paced at known locations. The method was tested using 7 realistic heart-torso models with PVCs in endocardial, epicardial, and intramural tissue. With 10 pacing sites, 95 % of the targets had been approximated to less than 5 mm. We conclude that although the convergence is sometimes erratic, the proposed method does converge to the origin, often within the radius of an ablation lesion.
Published: 2020

8. A Patchwork Inverse Method in Combination with the Activation Time Gradient to Detect Regions of Slow Conduction in Sinus Rhythm

Author: Rémi Dubois, Lisl Weynans, Mark Potse, Laura Bear, Oumayma Bouhamama, Université de Bordeaux (UB), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de rythmologie et modélisation cardiaque [Pessac] (IHU Liryc), This work was supported by the French National Research Agency (ANR-10-IAHU04-LIRYC).This work was granted access to HPC resources of CINES under GENCI allocation 2020-A0070307379., Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: [SDV]Life Sciences [q-bio], 0206 medical engineering, Healthy tissue, 02 engineering and technology, 030204 cardiovascular system & hematology, Inverse problem, Thermal conduction, 020601 biomedical engineering, k-nearest neighbors algorithm, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Electrocardiographic imaging, Tissue damage, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Sinus rhythm, Biological system, Inverse method, Geology, ComputingMilieux_MISCELLANEOUS, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA]
Abstract: International audience; Background: Noninvasive electrocardiographic imaging (ECGI) provides real-time panoramic images of epicardial electrical activity from potential measurements on the torso surface. Several numerical methods are commonly used for ECGI, including the finite-element method (FEM), the boundary-element method (BEM) and the method of fundamental solutions (MFS). However, doubts remain about the ability of these methods to detect the presence of regions of slow conduction in structurally abnormal hearts.Objective: The purpose of this study was to develop a method toassess the ability of ECGI to find regions of slow conduction in sinus rhythm.Method: Slow conduction was inferred from large activation time gradients. To determine these gradients we computed the activation time difference between each node and all other nodes within 10 mm, and tested five different methods (maximum, minimum, average, nearest neighbour and random) to define a unique difference value at each node. To estimate the activation times themselves, we tested the current ECGI methods (FEM, MFS) and a novel numerical method called the Patchwork Method (PM), which locally chooses the optimal ECGI method.Results: Two methods of computing activation time gradients (maximum and average) accurately located 6 of the 7 zones of tissue damage. Furthermore, the PM method succeeded in locating 5 of the 6 slow conduction zones recorded whereas classical ECGI methods did not locate any damaged zone.Conclusion: In this study, the novel ECGI approach presented is an efficient tool to help overcome some of the limitations of classical numerical methods in sinus rhythm in structurally abnormal hearts, showing its ability in detecting regions of slow conduction by using the average or maximum activation time gradient.
Published: 2020

9. Modelling the action potential propagation in a heart with structural heterogeneities: From high‐resolution MRI to numerical simulations

Author: Yves Bourgault, Yves Coudière, Anđela Davidović, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Institut de rythmologie et modélisation cardiaque [Pessac] (IHU Liryc), Institut Pasteur [Paris] (IP), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], University of Ottawa [Ottawa], This work was funded by the ANR project HR-CEM reference ANR-13-MONU-0004. This work was partially supported by an ANR grant part of ‘Investments d'Avenir’ program reference ANR-10-IAHU-04 and a Discovery Grant of the National Science and Engineering Council of Canada to Y.B, The authors would like to thank Stephen Gilbert for providing HR MRI and DT MRI data of the rat heart, and for the useful discussions about the imaging process. The authors would like to thank Mehdi Juhoor and Marc Fuentes for help on using and developing the code in CEPS. The authors would also like to thank Mehdi Juhoor and Pauline Migerditichan for help in using Music., ANR-13-MONU-0004,HR-CEM,Modèles numériques haute résolution de l'électrophysiologie cardiaque(2013), ANR-10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)
Subjects: Materials science, Action potential, 0206 medical engineering, Biomedical Engineering, Action Potentials, High resolution, Image processing, 02 engineering and technology, 030204 cardiovascular system & hematology, Multiscale modelling, 03 medical and health sciences, 0302 clinical medicine, Heart Conduction System, Animals, Computer Simulation, [MATH]Mathematics [math], Molecular Biology, Heterogeneous conductivities, Wavefront, Computer simulation, Cardiac electrophysiology, Applied Mathematics, Models, Cardiovascular, Bidomain model, Heart, Mechanics, Fibrosis, Magnetic Resonance Imaging, 020601 biomedical engineering, Action (physics), Rats, Image-based modelling, Computational Theory and Mathematics, Modeling and Simulation, Software
Abstract: International audience; Mathematical modelling and numerical simulation in cardiac electrophysiology have already been studied extensively. However, there is a clear lack of techniques and methodologies for studying the propagation of action potential in a heart with structural defects. In this article, we present a modified version of the bidomain model, derived using homogenisation techniques with the assumption of existence of diffusive inclusions in the cardiac tissue. The diffusive inclusions represent regions without electrically active myocytes, for example, fat, fibrosis, and so forth. We present an application of this model to a rat heart. Starting from high-resolution MRI, the geometry of the heart is built and meshed using image processing techniques. We perform a study of the effects of tissue heterogeneities induced by diffusive inclusions on the velocity and shape of the depolarisation wavefront. We present several test cases with different geometries of diffusive inclusions. We reach the conclusion that the conduction velocity is not affected in the best cases, while it is affected by up to 76% in the worst case scenario. Additionally, the shape of the wavefront was affected in some cases.
Published: 2020

10. Epicardial Fibrosis Explains Increased Endo-Epicardial Dissociation and Epicardial Breakthroughs in Human Atrial Fibrillation

Author: Ali Gharaviri, Elham Bidar, Mark Potse, Stef Zeemering, Sander Verheule, Simone Pezzuto, Rolf Krause, Jos G. Maessen, Angelo Auricchio, Ulrich Schotten, Fysiologie, Promovendi CD, CTC, MUMC+: MA Med Staf Spec CTC (9), RS: Carim - H08 Experimental atrial fibrillation, MUMC+: MA Cardiothoracale Chirurgie (3), RS: Carim - V04 Surgical intervention, Center for Computational Medicine in Cardiology [Lugano], Università della Svizzera italiana = University of Italian Switzerland (USI), Maastricht University Medical Centre (MUMC), Maastricht University [Maastricht], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Faculty of Informatics [Lugano], Center for Computational Medicine in Cardiology (CCMC), Fondazione Cardiocentro Ticino, Department of Physiology [Maastricht], This work was supported by grants from the Dutch Heart Foundation (CVON2014-09, RACE V: Reappraisal of Atrial Fibrillation: Interaction between hyperCoagulability, Electrical remodeling, and Vascular Destabilisation in the Progression of AF), the European Union (CATCH ME: Characterizing Atrial fibrillation by Translating its Causes into Health Modifiers in the Elderly), No. 633196, the ITN Network AFibTrainNet, No. 675351, the ITN Network RADOX: RADical reduction of OXidative stress in cardiovascular diseases, No. PITN-GA-2012-316738, the ERACoSysMED H2020 ERA-NET Cofund project Systems medicine for diagnosis and stratification of atrial fibrillation, the Swiss National Supercomputing Centre (CSCS) (project IDs s668 and s778), CEA-TGCC under GENCI allocation 2018-A0030307379, and the French National Research Agency (ANR-10-IAHU04-LIRYC). The authors acknowledge financial support by the Theo Rossi di Montelera Foundation, the Metis Foundation Sergio Mantegazza, the Fidinam Foundation, and the Horten Foundation to the Center for Computational Medicine in Cardiology., Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), University of Zurich, and Schotten, Ulrich
Subjects: 0301 basic medicine, DYNAMICS, medicine.medical_specialty, conduction, MUSCULATURE, Physiology, 610 Medicine & health, substrate, PROPAGATION, 030204 cardiovascular system & hematology, insights, 11171 Cardiocentro Ticino, lcsh:Physiology, Nerve conduction velocity, MECHANISMS, 03 medical and health sciences, 2737 Physiology (medical), 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Fibrosis, Physiology (medical), Internal medicine, medicine, atrial fibrillation, CONNECTIONS, Cycle length, Original Research, EED, Fibrillation, COMPLEXITY, lcsh:QP1-981, business.industry, fibrosis, Atrial fibrillation, methodology, 1314 Physiology, medicine.disease, 030104 developmental biology, transmural conduction, Cardiology, computer models, Mr images, medicine.symptom, breakthrough waves, business
Abstract: BackgroundAtrial fibrillation (AF) is accompanied by progressive epicardial fibrosis, dissociation of electrical activity between the epicardial layer and the endocardial bundle network, and transmural conduction (breakthroughs). However, causal relationships between these phenomena have not been demonstrated yet. Our goal was to test the hypothesis that epicardial fibrosis suffices to increase endo-epicardial dissociation (EED) and breakthroughs (BT) during AF.MethodsWe simulated the effect of fibrosis in the epicardial layer on EED and BT in a detailed, high-resolution, three-dimensional model of the human atria with realistic electrophysiology. The model results were compared with simultaneous endo-epicardial mapping in human atria. The model geometry, specifically built for this study, was based on MR images and histo-anatomical studies. Clinical data were obtained in four patients with longstanding persistent AF (persAF) and three patients without a history of AF.ResultsThe AF cycle length (AFCL), conduction velocity (CV), and EED were comparable in the mapping studies and the simulations. EED increased from 24.1 +/- 3.4 to 56.58 +/- 6.2% (p < 0.05), and number of BTs per cycle from 0.89 +/- 0.55 to 6.74 +/- 2.11% (p < 0.05), in different degrees of fibrosis in the epicardial layer. In both mapping data and simulations, EED correlated with prevalence of BTs. Fibrosis also increased the number of fibrillation waves per cycle in the model. ConclusionA realistic 3D computer model of AF in which epicardial fibrosis was increased, in the absence of other pathological changes, showed increases in EED and epicardial BT comparable to those in longstanding persAF. Thus, epicardial fibrosis can explain both phenomena.
Published: 2020

11. The 'Digital Twin' to enable the vision of precision cardiology

Author: Pras Pathmanathan, Liesbet Geris, Yingjing Feng, Francesca Margara, Andrew Gilbert, Espen W. Remme, Alfonso Bueno-Orovio, Joao Filipe Fernandes, Mark Potse, Marta Sitges, Blanca Rodriguez, Viatcheslav Gurev, Tammo Delhaas, Tina M. Morrison, Manuel Villegas Martinez, Pablo Lamata, Ali Wajdan, Ada Doltra, Filip Loncaric, Hassaan A. Bukhari, Richard Cornelussen, Paul Leeson, Paolo DiAchille, Frits W. Prinzen, Peter Mortier, Manuel Mayr, Hongxing Luo, Edward J. Vigmond, Mehrdad Shamohammdi, Esther Pueyo, Kristin McLeod, Philip Westphal, Vicente Grau, Jorge Corral-Acero, Ernesto Zacur, Steven A. Niederer, Mariana Sousa Santos, Maciej Marciniak, Cristobal Rodero, Department of Engineering Science [Oxford], Institute of Biomedical Engineering [Oxford] (IBME), University of Oxford [Oxford]-University of Oxford [Oxford], Department of Computer Science [Oxford], University of Oxford [Oxford], King‘s College London, Universitat de Barcelona (UB), Institut de rythmologie et modélisation cardiaque [Pessac] (IHU Liryc), Oslo University Hospital [Oslo], Aragón Institute of Engineering Research [Zaragoza] (I3A), University of Zaragoza - Universidad de Zaragoza [Zaragoza], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), FEops, Maastricht University [Maastricht], Medtronic Bakken Research Center BV, John Radcliffe Hospital [Oxford University Hospital], IBM Thomas J. Watson Research Center, IBM, Virtual Physiological Human Institute [Leuven] (VPH), U.S. Food and Drug Administration (FDA), Cardiovascular Research Institute Maastricht (CARIM), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Oslo (UiO), GE Vingmed Ultrasound AS, IHU-LIRYC, CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Instituto de Salud Carlos III [Madrid] (ISC)-ministerio de ciencia e innovacion, This work was supported by the EU’s Horizon 2020 Marie Sklodowska-Curie ITN Projects (g.a. 764738 and 766082), the EU’s Horizon 2020 research and (g.a. 675451 and 823712), the Wellcome/EPSRC Centre for Medical Engineering (WT 203148/Z/16/Z), the National Research Agency (ANR) (g.a. ANR-10-IAHU-04), theNC3RS (NC/P001076/1) and the British Heart Foundation (RE/13/2/30182, RE/13/1/30181, TG/17/3/33406, PG/16/75/32383, FS/17/22/32644, CH/16/3/21406, RG/16/14/32397). E.Pueyo holds an ERC StartingGrant (g.a. 638284). B. Rodriguez and P. Lamata hold Wellcome TrustSenior Research Fellowships (214290/Z/18/Z, 209450/Z/17/Z)., ANR-10-IAHU-04/10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), ANR-10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), University of Oxford-University of Oxford, University of Oxford, Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: Artificial intelligence, Cardiac & Cardiovascular Systems, INFORMATION, diagnosis, 030204 cardiovascular system & hematology, 0302 clinical medicine, CHANNEL, Medicine, AcademicSubjects/MED00200, RISK, 0303 health sciences, Computational model, ARTIFICIAL-INTELLIGENCE, Precision medicine, twins, 3. Good health, cardiology, HEART, TRIAL, Cardiology and Cardiovascular Medicine, Life Sciences & Biomedicine, Algorithms, Digital Health and Innovation, vision, Boosting (machine learning), BIG DATA, Cardiovascular research, MEDLINE, PRESSURE, 03 medical and health sciences, models, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, computer simulation, Extensive data, State of the Art Review, Humans, 030304 developmental biology, Science & Technology, BLOOD-FLOW, business.industry, MEDICINE, Statistical model, PERFORMANCE, CT ANGIOGRAPHY, Data science, Digital twin, Computational modelling, Cardiovascular System & Cardiology, Position paper, precision, business, statistical
Abstract: Providing therapies tailored to each patient is the vision of precision medicine, enabled by the increasing ability to capture extensive data about individual patients. In this position paper, we argue that the second enabling pillar towards this vision is the increasing power of computers and algorithms to learn, reason, and build the 'digital twin' of a patient. Computational models are boosting the capacity to draw diagnosis and prognosis, and future treatments will be tailored not only to current health status and data, but also to an accurate projection of the pathways to restore health by model predictions. The early steps of the digital twin in the area of cardiovascular medicine are reviewed in this article, together with a discussion of the challenges and opportunities ahead. We emphasize the synergies between mechanistic and statistical models in accelerating cardiovascular research and enabling the vision of precision medicine. ispartof: EUROPEAN HEART JOURNAL vol:41 issue:48 pages:4556-+ ispartof: location:England status: published
Published: 2020

12. A publicly available virtual cohort of four-chamber heart meshes for cardiac electro-mechanics simulations

Author: Karli Gillette, Gernot Plank, Marina Strocchi, Christopher A. Rinaldi, Orod Razeghi, Edward J. Vigmond, Justin Gould, Matthias A. F. Gsell, Martin J. Bishop, Aurel Neic, Baldeep S. Sidhu, Elias Karabelas, Anton J. Prassl, Jonathan M. Behar, Christoph M. Augustin, Steven A. Niederer, King‘s College London, Medical University Graz, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Imaging Sciences and Biomedical Engineering Division [London], Guy's and St Thomas' Hospital [London]-King‘s College London, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: Male, Computer science, 030204 cardiovascular system & hematology, Ventricular Function, Left, 030218 nuclear medicine & medical imaging, Diagnostic Radiology, Cohort Studies, 0302 clinical medicine, Medicine and Health Sciences, Pulmonary Arteries, Tomography, ComputingMilieux_MISCELLANEOUS, Aorta, Aged, 80 and over, Computational model, Multidisciplinary, Ejection fraction, Orientation (computer vision), Radiology and Imaging, Simulation and Modeling, Heart, Stroke volume, Arteries, Middle Aged, Medicine, [SDV.IB]Life Sciences [q-bio]/Bioengineering, Female, Anatomy, Research Article, Adult, Cardiac Ventricles, Imaging Techniques, Science, Heart Ventricles, Neuroimaging, Research and Analysis Methods, Veins, 03 medical and health sciences, Diagnostic Medicine, medicine.artery, medicine, Humans, Polygon mesh, Computer Simulation, Endocardium, Aged, Heart Failure, Myocardium, Cardiac Ventricle, Biology and Life Sciences, Surgical Mesh, medicine.disease, Computed Axial Tomography, Heart failure, Ventricular Function, Right, Cardiovascular Anatomy, Blood Vessels, Biomedical engineering, Neuroscience
Abstract: Computational models of the heart are increasingly being used in the development of devices, patient diagnosis and therapy guidance. While software techniques have been developed for simulating single hearts, there remain significant challenges in simulating cohorts of virtual hearts from multiple patients. To facilitate the development of new simulation and model analysis techniques by groups without direct access to medical data, image analysis techniques and meshing tools, we have created the first publicly available virtual cohort of twenty-four four-chamber hearts. Our cohort was built from heart failure patients, age 6714 years. We segmented four-chamber heart geometries from end-diastolic (ED) CT images and generated linear tetrahedral meshes with an average edge length of 1.10.2mm. Ventricular fibres were added in the ventricles with a rule-based method with an orientation of -60 and 80 at the epicardium and endocardium, respectively. We additionally refined the meshes to an average edge length of 0.390.10mm to show that all given meshes can be resampled to achieve an arbitrary desired resolution. We ran simulations for ventricular electrical activation and free mechanical contraction on all 1.1mm-resolution meshes to ensure that our meshes are suitable for electro-mechanical simulations. Simulations for electrical activation resulted in a total activation time of 14916ms. Free mechanical contractions gave an average left ventricular (LV) and right ventricular (RV) ejection fraction (EF) of 351% and 302%, respectively, and a LV and RV stroke volume (SV) of 9528mL and 6511mL, respectively. By making the cohort publicly available, we hope to facilitate large cohort computational studies and to promote the development of cardiac computational electro-mechanics for clinical applications. (VLID)5215097 Version of record
Published: 2020

13. Advantages and pitfalls of noninvasive electrocardiographic imaging

Author: Matthijs J. M. Cluitmans, Rémi Dubois, Josselin Duchateau, Laura Bear, Richard D. Walton, Olivier Bernus, Michel Haïssaguerre, Oumayma Bouhamama, Ruben Coronel, Charly N.W. Belterman, Emma Abell, Centre de recherche Cardio-Thoracique de Bordeaux [Bordeaux] (CRCTB), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut National de la Santé et de la Recherche Médicale (INSERM), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Cardiology, ACS - Heart failure & arrhythmias, Cardiologie, RS: Carim - H04 Arrhythmogenesis and cardiogenetics, RS: CARIM - R2 - Cardiac function and failure, and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest
Subjects: Diagnostic Imaging, medicine.medical_specialty, Non-invasive electrocardiography, Swine, [SDV]Life Sciences [q-bio], POTENTIALS, Regional perfusion, Activation, Repolarization, Dofetilide, 030204 cardiovascular system & hematology, VALIDATION, 03 medical and health sciences, QRS complex, Electrocardiography, 0302 clinical medicine, Internal medicine, Medicine, Animals, Sinus rhythm, 030212 general & internal medicine, business.industry, Left bundle branch block, ABNORMALITIES, Diagnostic Tests, Routine, Body Surface Potential Mapping, Arrhythmias, Cardiac, Torso, medicine.disease, medicine.anatomical_structure, Electrocardiographic imaging, Torso tank, Cardiology, Cardiology and Cardiovascular Medicine, business, medicine.drug
Abstract: Background: With increasing clinical use of Electrocardiographic Imaging (ECGI), it is imperative to understand the limits of this technique. The objective of this study is to evaluate a potential-based ECGI approach for activation and repolarization mapping in sinus rhythm.Method: Langendorff-perfused pig hearts were suspended in a human-shaped torso tank. Electrograms were recorded with a 108-electrode sock and ECGs with 256 electrodes embedded in the tank surface. Left bundle branch block (LBBB) was developed in 4 hearts through ablation, and repolarization abnormalities in another 4 hearts through regional perfusion of dofetilide and pinacidil. Electrograms were noninvasively reconstructed and reconstructed activation and repolarization features were compared to those recorded.Results: Visual consistency between ECGI and recorded activation and repolarization maps was high. While reconstructed repolarization times showed significantly more error than activation times quantitatively, patterns were reconstructed with a similar level of accuracy. The number of epicardial breakthrough sites was underestimated by ECGI and these were misplaced (>20 mm) in location. Likewise, ECGI reconstructed activation maps demonstrated artificial lines of block resulting from a W-shaped QRS waveform that were not present in recorded maps. Nevertheless, ECGI allowed identification of regions of abnormal repolarization reasonably accurately in terms of size, location and timing.Conclusions: This study validates a potential-based ECGI approach to noninvasively image activation and recovery in sinus rhythm. Despite inaccuracies in epicardial breakthroughs and lines of conduction block, other important clinical features such as regions of abnormal repolarization can be accurately derived making ECGI a valuable clinical tool. (C) 2019 The Authors. Published by Elsevier Inc.
Published: 2019

14. Direct Mapping from Body Surface Potentials to Cardiac Activation Maps Using Neural Networks

Author: Karoui, Amel, Bendahamane, Mostafa, Zemzemi, Nejib, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)
Subjects: 0303 health sciences, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, [INFO.INFO-NE]Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], 030204 cardiovascular system & hematology, ComputingMilieux_MISCELLANEOUS, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], 030304 developmental biology
Abstract: International audience
Published: 2019

15. Sensitivity analysis of ventricular activation and electrocardiogram in tailored models of heart-failure patients

Author: Angelo Auricchio, Frits W. Prinzen, Enrico G. Caiani, Francesco Maffessanti, Rolf Krause, Gabriele D'Ambrosio, Carlos Sánchez, Mark Potse, University of Zurich, Sánchez, C, Center for Computational Medicine in Cardiology [Lugano], Università della Svizzera italiana = University of Italian Switzerland (USI), Cardiocentro Ticino [Lugano], Universität Zürich [Zürich] = University of Zurich (UZH), Dipartimento di Elettronica, Informazione e Bioingegneria (DEIB), Politecnico di Milano [Milan] (POLIMI), Maastricht University [Maastricht], Faculty of Informatics [Lugano], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Swiss National Supercomputing Centre (CSCS) project ID s598, Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Fysiologie, RS: CARIM - R2.08 - Electro mechanics, and Biomedische Technologie
Subjects: Male, medicine.medical_treatment, 02 engineering and technology, 030204 cardiovascular system & hematology, Electrocardiography, 0302 clinical medicine, MAGNETIC-RESONANCE, Computer simulation, ECG morphology, Heart failure, Left bundle branch block, Patient-specific model, Sensitivity analysis, Biomedical Engineering, Computer Science Applications1707 Computer Vision and Pattern Recognition, medicine.diagnostic_test, Models, Cardiovascular, Middle Aged, Computer Science Applications, VARIABILITY, Ventricular activation, Cardiology, MESH: Mathematical Computation, Female, CARDIAC RESYNCHRONIZATION THERAPY, RHYTHM, ARRHYTHMOGENESIS, BUNDLE-BRANCH BLOCK, medicine.medical_specialty, Heart Ventricles, 0206 medical engineering, Cardiac resynchronization therapy, 2204 Biomedical Engineering, 610 Medicine & health, 11171 Cardiocentro Ticino, CELLULAR ELECTROPHYSIOLOGY, 03 medical and health sciences, QRS complex, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Internal medicine, medicine, 1706 Computer Science Applications, Humans, Sensitivity (control systems), MESH: Cardiac electrophysiology, Aged, Demography, Bundle branch block, business.industry, CONDUCTION DEFECTS, Magnetic resonance imaging, medicine.disease, 020601 biomedical engineering, TISSUE, MESH: Heart Failure, PATTERNS, business, Biomedical engineering
Abstract: International audience; Cardiac resynchronization therapy is not effective in a variable proportion of heart failure patients. An accurate knowledge of each patient's electroanatomical features could be helpful to determine the most appropriate treatment. The goal of this study was to analyze and quantify the sensitivity of left ventricular (LV) activation and the electrocardiogram (ECG) to changes in 39 parameters used to tune realistic anatomical-electrophysiological models of the heart. Electrical activity in the ventricles was simulated using a reaction-diffusion equation. To simulate cellular electrophysiology, the Ten Tusscher-Panfilov 2006 model was used. Intracardiac electrograms and 12-lead ECGs were computed by solving the bidomain equation. Parameters showing the highest sensitivity values were similar in the six patients studied. QRS complex and LV activation times were modulated by the sodium current, the cell surface-to-volume ratio in the LV, and tissue conductivities. The T-wavewas modulated by the calcium and rectifier-potassium currents, and the cell surface-to-volume ratio in both ventricles. We conclude that homogeneous changes in ionic currents entail similar effects in all ECG leads, whereas the effects of changes in tissue properties show larger inter-lead variability. The effects of parameter variations are highly consistent between patients and most of the model tuning could be performed with only ~10 parameters.
Published: 2018

16. Fractionated electrograms with ST-segment elevation recorded from the human right ventricular outflow tract

Author: Igor R. Efimov, Ruben Coronel, Bastiaan J. Boukens, Edward J. Vigmond, Stacey Rentschler, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Washington University in Saint Louis (WUSTL), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Cardiology, ACS - Amsterdam Cardiovascular Sciences, Medical Biology, ACS - Heart failure & arrhythmias, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, medicine.medical_specialty, Case Report, RVOT, 030204 cardiovascular system & hematology, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Internal medicine, medicine, Diseases of the circulatory (Cardiovascular) system, ST segment, Ventricular outflow tract, Brugada syndrome, Fractionation, ComputingMilieux_MISCELLANEOUS, business.industry, Elevation, 16. Peace & justice, medicine.disease, 030104 developmental biology, RC666-701, Cardiology, Cardiology and Cardiovascular Medicine, business
Abstract: International audience
Published: 2017

17. The relation between local repolarization and T-wave morphology in heart failure patients

Author: Angelo Auricchio, Maria Luce Caputo, Daniel Sürder, Annekatrin Illner, Joris Wanten, Tiziano Moccetti, François Regoli, Francesco Maffessanti, Giulio Conte, Frits W. Prinzen, Rolf Krause, Mark Potse, Center for Computational Medicine in Cardiology [Lugano], Università della Svizzera italiana = University of Italian Switzerland (USI), Maastricht University [Maastricht], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Cardiocentro Ticino [Lugano], Universität Zürich [Zürich] = University of Zurich (UZH), Otto-von-Guericke University [Magdeburg] (OVGU), Swiss National Science Foundation project 32003B_165802, Theo Rossi di Montelera Foundation, Metis Foundation Sergio Mantegazza, Fidinam Foundation, Horten Foundation, Biologic Delivery Systems, Biosense Webster, a Johnson & Johnson Company, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2, Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Otto-von-Guericke-Universität Magdeburg = Otto-von-Guericke University [Magdeburg] (OVGU), RS: CARIM - R2.08 - Electro mechanics, Fysiologie, University of Zurich, and Prinzen, Frits W
Subjects: 0301 basic medicine, Male, medicine.medical_treatment, Repolarization, 030204 cardiovascular system & hematology, ACTIVATION, Electrocardiography, 0302 clinical medicine, Prospective Studies, Aged, 80 and over, Left bundle branch block, ACTION-POTENTIAL DURATION, Depolarization, Middle Aged, MESH: Cardiac Electrophysiology, medicine.anatomical_structure, Cardiology, Female, CARDIAC RESYNCHRONIZATION THERAPY, VENTRICULAR REPOLARIZATION, Cardiology and Cardiovascular Medicine, CANINE, BUNDLE-BRANCH BLOCK, medicine.medical_specialty, Cardiac resynchronization therapy, GRADIENTS, 610 Medicine & health, Heart failure, Electro-anatomic mapping, 11171 Cardiocentro Ticino, 2705 Cardiology and Cardiovascular Medicine, 03 medical and health sciences, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Heart Conduction System, Internal medicine, medicine, Humans, MODULATION, Coronary sinus, Aged, ARRHYTHMIAS, Bundle branch block, business.industry, MEMORY, Stroke Volume, MESH: C14.280.434, medicine.disease, 030104 developmental biology, Ventricle, T-wave, business
Abstract: Background: Both duration and morphology of the T-wave are regarded important parameters describing repolarization of the ventricles. Conventionally, T-wave concordance is explained by an inverse relation between the time of depolarization (TD) and repolarization (TR). Little is known about T-wave morphology and TD-TR relations in patients with heart failure.Methods: Electro-anatomic maps were obtained in the left (LV) and right ventricle (RV) and in the coronary sinus (CS) in patients with heart failure with narrow (nQRS, n = 8) and wide QRS complex with (LBBB, n = 15) and without left bundle branch block (non-LBBB, n = 7). TD and TR were determined from the thus acquired electrograms.Results: In nQRS and non-LBBB patients, TD-TR relations had a slope between 0 and +1, indicating that repolarization followed the sequence of depolarization. In LBBB patients, repolarization occurred significantly earlier in the RV than in the LV, fitting with the idea that the discordant T-waves in LBBB are secondary to the abnormal depolarization sequence. However, the slopes of the TD-TR relations in the LV and CS were not significantly different from zero, indicating no major spatial gradient in LV repolarization, despite a considerable gradient in depolarization. Remarkable was also the large (similar to 100ms) transseptal gradient in repolarization. Values of the slopes of the TD-TR relation overlapped between the three patient groups, despite a difference in T-wave morphology between LBBB (all discordant) and nQRS patients (all flat/biphasic).Conclusions: Discordant T-waves in LBBB patients are explained by interventricular dispersion in repolarization. T-wave morphology is determined by more factors than the TD-TR relation alone. (C) 2017 The Authors. Published by Elsevier Ireland Ltd.
Published: 2017

18. Rate-Dependent Role of I Kur in Human Atrial Repolarization and Atrial Fibrillation Maintenance

Author: Stanley Nattel, Philippe Comtois, Jianlin Feng, Edward J. Vigmond, Martin Aguilar, Université de Montréal (UdeM), Bristol-Myers Squibb Company, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: 0301 basic medicine, Membrane potential, Atrial Repolarization, Chemistry, Medizin, Biophysics, Rate dependent, Atrial fibrillation, Potassium channel blocker, 030204 cardiovascular system & hematology, medicine.disease, Potassium channel, Toxicology, 03 medical and health sciences, 030104 developmental biology, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, medicine, Repolarization, Anti-Arrhythmia Agents, medicine.drug
Abstract: International audience; The atrial-specific ultrarapid delayed rectifier K+ current (IKur) inactivates slowly but completely at depolarized voltages. The consequences for IKur rate-dependence have not been analyzed in detail and currently available mathematical action-potential (AP) models do not take into account experimentally observed IKur inactivation dynamics. Here, we developed an updated formulation of IKur inactivation that accurately reproduces time-, voltage-, and frequency-dependent inactivation. We then modified the human atrial cardiomyocyte Courtemanche AP model to incorporate realistic IKur inactivation properties. Despite markedly different inactivation dynamics, there was no difference in AP parameters across a wide range of stimulation frequencies between the original and updated models. Using the updated model, we showed that, under physiological stimulation conditions, IKur does not inactivate significantly even at high atrial rates because the transmembrane potential spends little time at voltages associated with inactivation. Thus, channel dynamics are determined principally by activation kinetics. IKur magnitude decreases at higher rates because of AP changes that reduce IKur activation. Nevertheless, the relative contribution of IKur to AP repolarization increases at higher frequencies because of reduced activation of the rapid delayed-rectifier current IKr. Consequently, IKur block produces dose-dependent termination of simulated atrial fibrillation (AF) in the absence of AF-induced electrical remodeling. The inclusion of AF-related ionic remodeling stabilizes simulated AF and greatly reduces the predicted antiarrhythmic efficacy of IKur block. Our results explain a range of experimental observations, including recently reported positive rate-dependent IKur-blocking effects on human atrial APs, and provide insights relevant to the potential value of IKur as an antiarrhythmic target for the treatment of AF.
Published: 2017

19. Stability Analysis of Decoupled Time-stepping Schemes for the Specialized Conduction System/myocardium Coupled Problem in Cardiology

Author: Nejib Zemzemi, S. Mani Aouadi, W. Mbarki, Faculté des Sciences Mathématiques, Physiques et Naturelles de Tunis (FST), Université de Tunis El Manar (UTM), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), LIRIMA, EPICARD, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: 0301 basic medicine, Coupling, Work (thermodynamics), Discretization, Applied Mathematics, Stability (learning theory), 030204 cardiovascular system & hematology, Topology, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Finite element method, 03 medical and health sciences, 030104 developmental biology, 0302 clinical medicine, Control theory, Modeling and Simulation, Reaction–diffusion system, Monodomain model, Energy (signal processing), Mathematics
Abstract: International audience; The Purkinje network is the rapid conduction system in the heart. It ensures the physiological spread of the electrical wave in the ventricles. In this work, we consider a problem that models the coupling between the Purkinje network and the myocardium. We first prove the stability of the space semi-discretized problem. Then we present four different strategies for solving the Purkinje/ myocardium coupling. The strategies are based on different time discretization of the coupling terms. The first scheme is fully coupled, where the coupling terms are considered implicit. The second and the third schemes are based on Gauss-Seidel time-splitting schemes where one coupling term is considered explicit and the other is implicit. The last is a Jacobi-like time-splitting scheme where both coupling terms are considered explicit. Our main result is the proof of the stability of the three considered schemes under the same restriction on the time step. Moreover, we show that the energy of the problem is slightly affected by the time-splitting schemes. We illustrate the theoretical result by different numerical simulations in 2D. We also conduct 3D simulations using physiologically detailed ionic models.
Published: 2017

20. An Analytical Model for the Effects of the Spatial Resolution of Electrode Systems on the Spectrum of Cardiac Signals

Author: Nejib Zemzemi, Jesus Requena-Carrion, Ferney A. Beltran-Molina, Felipe Alonso-Atienza, Universidad Escuela Colombiana de Carreras Industriales (ECCI), Queen Mary University of London (QMUL), Universidad Rey Juan Carlos [Madrid] (URJC), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)
Subjects: Cardiac arrhythmias, General Computer Science, 0206 medical engineering, bio-electric model, dominant frequency, spatiotemporal dynamics, 02 engineering and technology, 030204 cardiovascular system & hematology, Transfer function, Correlation, 03 medical and health sciences, 0302 clinical medicine, Statistics, General Materials Science, Spatiotemporal correlation, spatial resolution, Image resolution, Physics, Bandwidth (signal processing), General Engineering, Dominant frequency, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, 020601 biomedical engineering, bioelectric model, Electrode, lcsh:Electrical engineering. Electronics. Nuclear engineering, Biological system, lcsh:TK1-9971
Abstract: International audience; It has been suggested that the spatiotemporal characteristics of complex cardiac arrhythmias can be extracted from the spectrum of cardiac signals. However, the analysis of simple bioelectric models indicates that the spectrum of cardiac signals can be affected by the spatial resolution of the electrode system. In this study, we derive exact measurement transfer functions relating the spectrum of cardiac signals to the spatiotemporal dynamics of cardiac sources and estimate their bandwidths. The analysis of the measurement transfer bandwidths for dynamics with different degrees of spatiotemporal correlation shows that as the spatial resolution decreases, the bandwidth of the measurement transfer function decreases until it reaches a constant value. Moreover, this transition from decreasing to constant values is determined by the degree of spatiotemporal correlation of the underlying cardiac source. Motivated by our analytical results, we investigate in a realistic computer simulation environment the impact of additive noise on the accuracy of body-surface dominant frequency (DF) maps. Our simulation results show that meaningful DF values are obtained on those locations where the analytical measurement transfer bandwidth is wide. These findings suggest that the accuracy of body-surface DF maps can be limited by the low spatial resolution of body-surface electrode systems.
Published: 2017

21. Inducibility of Atrial Fibrillation Depends Chaotically on Ionic Model Parameters

Author: Mark Potse, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), This work was granted access to HPC resources of CEA-TGCC and IDRIS under GENCI allocation 2019-A0050307379. This work was supported by the French National Research Agency, grant reference ANR-10-IAHU04-LIRYC., ANR-05-PADD-0010,GeDuQue,Innovations agro-écologiques et organisationnelles pour une Gestion Durable de la Qualité de l'Eau dans des régions de monoculture à forts niveaux d'intrants phytosanitaires(2005), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: 0303 health sciences, 03 medical and health sciences, 0302 clinical medicine, 030204 cardiovascular system & hematology, [MATH]Mathematics [math], 030304 developmental biology
Abstract: International audience; Previous work has shown that fibrillation can be induced by rapid pacing in a model of the human atria without fibrosis or repolarization heterogeneity. The purpose of this study was to investigate how sensitive this type of arrhythmia induction is to model parameters.Simulations were performed with a monodomain reaction-diffusion model with Courtemanche dynamics on a volumetric atrial mesh with all the major bundle structures and layered fiber orientation. The ionic model parameters were modified to represent electrically remodeled atria, uniformly. The model was stimulated with decreasing cycle length to drive the atria to maximum rate, and simulated over 10 seconds. This was tried with 10 different pacing locations and 46 different values of the conductivity, GCaL, of the L-type calcium current.For GCaL values up to 130% of the initial value, on average 4 out of 10 pacing sites induced AF. However, the positive sites were different for each tested GCaL level, even at 1% increments. Beyond 130%, the AF induction rate decreased. Every pacing site yielded AF for a subset of parameter values, but some sites more frequently.In conclusion, AF induction is highly sensitive to parameter values. The global decrease in induction seen for large GCaL may be due to the increased wavelength.
Published: 2019

22. In-Silico Evaluation of an Iterative Pace-Mapping Technique to Guide Catheter Ablation of Ventricular Ectopy

Author: Andony Arrieula, Hubert Cochet, Pierre Jaïs, Michel Haïssaguerre, Mark Potse, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Université de Bordeaux (UB), Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Haut-Lévêque [CHU Bordeaux], CHU Bordeaux [Bordeaux], This work was supported by the Région Nouvelle-Aquitaine, grant nr. 2017 – 1R50109 – 00013434, the European Research Council (H2020 grant agreement number 715093, ECSTATIC), and the French National Research Agency, grant references ANR-10-IAHU04-LIRYC and ANR-11-EQPX-0030. This work was granted access to HPC resources of CINES under GENCI allocation 2019-A0050307379, ANR-11-EQPX-0030,MUSIC,Plateforme multi-modale d'exploration en cardiologie(2011), ANR-10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Arrieula, Andony, Equipements d'excellence - Plateforme multi-modale d'exploration en cardiologie - - MUSIC2011 - ANR-11-EQPX-0030 - EQPX - VALID, and Instituts Hospitalo-Universitaires - L'Institut de Rythmologie et modélisation Cardiaque - - LIRYC2010 - ANR-10-IAHU-0004 - IAHU - VALID
Subjects: 0303 health sciences, 03 medical and health sciences, 0302 clinical medicine, [MATH] Mathematics [math], 030204 cardiovascular system & hematology, [MATH]Mathematics [math], 030304 developmental biology, 3. Good health
Abstract: International audience; Ventricular tachychardia (VT) is one of the mechanisms that induce sudden cardiac death. A way to cure VT is to ablate the exit site with an endocardial catheter. But it can be difficult, and sometimes impossible, to localize this exit site accurately enough. We propose a process to accelerate catheter ablation using an automatic method to guide the catheter towards the exit site. The proposed process uses the QRS complex integral of the 12-lead ECG. The method was tested using a realistic numerical forward model with pacing sites in endocardial, epicardial, and mid-myocardial tissue. With 12 pacing sites, 6 targets had been approximated to less than 1 mm. Five more were within 5 mm distance, and one was at 10 mm distance. We conclude that although the convergence is sometimes erratic, the proposed method does converge to the exit site, often within the radius of an ablation lesion.
Published: 2019

23. Space rescaling in the MFS method improves the ECGI reconstruction

Author: Pauline Migerditichan, Mark Potse, Nejib Zemzemi, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), This work was granted access to HPC resources of CINES under GENCIallocation 2019-A0050307379. This work was also supported by the French National Research Agency, grant references ANR-10-IAHU04-LIRYC., ANR-05-PADD-0010,GeDuQue,Innovations agro-écologiques et organisationnelles pour une Gestion Durable de la Qualité de l'Eau dans des régions de monoculture à forts niveaux d'intrants phytosanitaires(2005), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0303 health sciences, Correlation coefficient, Mathematical analysis, 030204 cardiovascular system & hematology, Inverse problem, Torso, Space (mathematics), 03 medical and health sciences, 0302 clinical medicine, medicine.anatomical_structure, Approximation error, medicine, Method of fundamental solutions, [MATH]Mathematics [math], Anisotropy, 030304 developmental biology, Test data, Mathematics
Abstract: International audience; The method of fundamental solutions (MFS) has been extensively used for the electrocardiographic imaging (ECGI) inverse problem. One of its advantages is that it is a meshless method. We remarked that the using cm instead of mm as a space unit has a high impact on the reconstructed inverse solution. Our purpose is to refine this observation, by introducing a rescaling coefficient in space and study its effect on the MFS inverse solution. Results are provided using simulated test data prepared using a reaction-diffusion model. We then computed the ECGI inverse solution for rescaling coefficient values varying from 1 to 100, and computed the relative error (RE) and correlation coefficient (CC). This approach improved the RE and CC by at least 10% but can go up to 40% independently of the pacing site. We concluded that the optimal coefficient depends on the heterogeneity and anisotropy of the torso and does not depend on the stimulation site. This suggests that it is related to an optimal equivalent conductivity estimation in the torso domain.
Published: 2019

24. Model assessment through data assimilation of realistic data in cardiac electrophysiology

Author: Annabelle Collin, Yves Coudière, Gautier Bureau, Antoine Gérard, Philippe Moireau, Service Expérimentation et Développement [Bordeaux] (SED), Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Modélisation Mathématique pour l'Oncologie (MONC), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Institut Bergonié [Bordeaux], UNICANCER-UNICANCER-Inria Bordeaux - Sud-Ouest, Laboratoire de mécanique des solides (LMS), École polytechnique (X)-Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Mathematical and Mechanical Modeling with Data Interaction in Simulations for Medicine (M3DISIM), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Inria Saclay - Ile de France, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Institut Bergonié [Bordeaux], École polytechnique (X)-MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-MINES ParisTech - École nationale supérieure des mines de Paris, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest
Subjects: Cardiac electrophysiology, Computer science, 0206 medical engineering, Anisotropic conductivity, Image processing, 02 engineering and technology, 030204 cardiovascular system & hematology, Cardiac modeling, 020601 biomedical engineering, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Synthetic data, Term (time), Electrophysiology, 03 medical and health sciences, 0302 clinical medicine, Data assimilation, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Sensitivity (control systems), Algorithm, Monodomain model
Abstract: International audience; We consider a model-based estimation procedure-namely a data assimilation algorithm-of the atrial depolarization state of a subject using data corresponding to electro-anatomical maps. Our objective is to evaluate the sensitivity of such a model-based reconstruction with respect to model choices. The followed data assimilation approach is capable of using electrical activation times to adapt a monodomain model simulation, thanks to an ingenious model-data fitting term inspired from image processing. The resulting simulation smoothes and completes the activation maps when they are spatially incomplete. Moreover, conductivity parameters can also be inferred. The model sensitivity assessment is performed based on synthetic data generated with a validated realistic atria model and then inverted using simpler modeling ingredients. In particular, the impact of the muscle fibers definition and corresponding anisotropic conductivity parameters is studied. Finally, an application of the method to real data is presented, showing promising results.
Published: 2019

25. Recent Advances in Understanding the Basic Mechanisms of Atrial Fibrillation Using Novel Computational Approaches

Author: Jichao Zhao, Oleg Aslanidi, Pawel Kuklik, Geoffrey Lee, Gary Tse, Steven Niederer, Edward J. Vigmond, University of Auckland [Auckland], King‘s College London, University Heart Center [Hamburg], The Royal Melbourne Hospital, University of Melbourne, The Chinese University of Hong Kong [Hong Kong], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: computational modeling, medicine.medical_specialty, Physiology, medicine.medical_treatment, 030204 cardiovascular system & hematology, lcsh:Physiology, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Internal medicine, medicine, computer simulation, atrial fibrillation, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, 0303 health sciences, lcsh:QP1-981, business.industry, Cardiac electrophysiology, Atrial fibrillation, Ablation, medicine.disease, Editorial, Cardiology, [SDV.IB]Life Sciences [q-bio]/Bioengineering, business, arrhythmia mechanisms, cardiac electrophysiology
Abstract: International audience
Published: 2019

26. Considering New Regularization Parameter-Choice Techniques for the Tikhonov Method to Improve the Accuracy of Electrocardiographic Imaging

Author: Judit Chamorro-Servent, Rémi Dubois, Yves Coudière, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), This study received financial support from the French Government under the Investments of the Future program managed by the National Research Agency (ANR), Grant reference ANR-10-IAHU-04 and from the Conseil Régional Aquitaine as part of the project Assimilation de données en cancérologie et cardiologie., Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Well-posed problem, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Computer science, Physiology, electrocardiography, 0206 medical engineering, Tikhonov, 02 engineering and technology, 030204 cardiovascular system & hematology, Regularization (mathematics), lcsh:Physiology, Tikhonov regularization, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), MFS, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging, Methods, Body surface, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Method of fundamental solutions, lcsh:QP1-981, ECG, Experimental data, Numerical models, [INFO.INFO-NA]Computer Science [cs]/Numerical Analysis [cs.NA], Inverse problem, ill-posed, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, 020601 biomedical engineering, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, regularization, [INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV], Electrocardiographic imaging, body surface potentials, inverse problem, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], Algorithm, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], Potentials
Abstract: International audience; The electrocardiographic imaging (ECGI) inverse problem highly relies on adding constraints, a process called regularization, as the problem is ill-posed. When there are no prior information provided about the unknown epicardial potentials, the Tikhonov regularization method seems to be the most commonly used technique. In the Tikhonov approach the weight of the constraints is determined by the regularization parameter. However, the regularization parameter is problem and data dependent, meaning that different numerical models or different clinical data may require different regularization parameters. Then, we need to have as many regularization parameter-choice methods as techniques to validate them. In this work, we addressed this issue by showing that the Discrete Picard Condition (DPC) can guide a good regularization parameter choice for the two-norm Tikhonov method. We also studied the feasibility of two techniques: The U-curve method (not yet used in the cardiac field) and a novel automatic method, called ADPC due its basis on the DPC. Both techniques were tested with simulated and experimental data when using the method of fundamental solutions as a numerical model. Their efficacy was compared with the efficacy of two widely used techniques in the literature, the L-curve and the CRESO methods. These solutions showed the feasibility of the new techniques in the cardiac setting, an improvement of the morphology of the reconstructed epicardial potentials, and in most of the cases of their amplitude.
Published: 2019

27. The Left and Right Ventricles Respond Differently to Variation of Pacing Delays in Cardiac Resynchronization Therapy: A Combined Experimental- Computational Approach

Author: Erik Willemen, Rick Schreurs, Peter R. Huntjens, Marc Strik, Gernot Plank, Edward Vigmond, John Walmsley, Kevin Vernooy, Tammo Delhaas, Frits W. Prinzen, Joost Lumens, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University [Maastricht], Maastricht University Medical Centre (MUMC), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Department of Physiology [Maastricht], European Space Agency (ESA), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Promovendi CD, Biomedische Technologie, RS: CARIM - R2 - Cardiac function and failure, Fysiologie, RS: CARIM - R2.08 - Electro mechanics, RS: CARIM - R2.09 - Cardiovascular system dynamics, MUMC+: MA Med Staf Artsass Cardiologie (9), Cardiologie, MUMC+: MA Med Staf Spec Cardiologie (9), RS: Carim - H07 Cardiovascular System Dynamics, RS: Carim - H08 Experimental atrial fibrillation, and RS: Carim - H06 Electro mechanics
Subjects: 0301 basic medicine, Optimization, medicine.medical_specialty, Cardiac output, Physiology, Therapy optimization studies, medicine.medical_treatment, Vascular damage Radboud Institute for Health Sciences [Radboudumc 16], CIRCULATION, Pump function, Cardiac resynchronization therapy, Hemodynamics, 030204 cardiovascular system & hematology, GUIDELINES, lcsh:Physiology, Contractility, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Internal medicine, REGRESSION, medicine, ADAPTATION, Original Research, lcsh:QP1-981, business.industry, Contractile response, CONTRACTILITY, Computer simulation, medicine.disease, Dyssynchrony, 030104 developmental biology, CircAdapt, Heart failure, Cardiology, cardiovascular system, HEART-FAILURE, DETERMINANT, Right ventricle, business, Atrioventricular block
Abstract: Contains fulltext : 209377.pdf (Publisher’s version ) (Open Access) Introduction: Timing of atrial, right (RV), and left ventricular (LV) stimulation in cardiac resynchronization therapy (CRT) is known to affect electrical activation and pump function of the LV. In this study, we used computer simulations, with input from animal experiments, to investigate the effect of varying pacing delays on both LV and RV electrical dyssynchrony and contractile function. Methods: A pacing protocol was performed in dogs with atrioventricular block (N = 6), using 100 different combinations of atrial (A)-LV and A-RV pacing delays. Regional LV and RV electrical activation times were measured using 112 electrodes and LV and RV pressures were measured with catheter-tip micromanometers. Contractile response to a pacing delay was defined as relative change of the maximum rate of LV and RV pressure rise (dP/dtmax) compared to RV pacing with an A-RV delay of 125 ms. The pacing protocol was simulated in the CircAdapt model of cardiovascular system dynamics, using the experimentally acquired electrical mapping data as input. Results: Ventricular electrical activation changed with changes in the amount of LV or RV pre-excitation. The resulting changes in dP/dtmax differed markedly between the LV and RV. Pacing the LV 10-50 ms before the RV led to the largest increases in LV dP/dtmax. In contrast, RV dP/dtmax was highest with RV pre-excitation and decreased up to 33% with LV pre-excitation. These opposite patterns of changes in RV and LV dP/dtmax were reproduced by the simulations. The simulations extended these observations by showing that changes in steady-state biventricular cardiac output differed from changes in both LV and RV dP/dtmax. The model allowed to explain the discrepant changes in dP/dtmax and cardiac output by coupling between atria and ventricles as well as between the ventricles. Conclusion: The LV and the RV respond in a opposite manner to variation in the amount of LV or RV pre-excitation. Computer simulations capture LV and RV behavior during pacing delay variation and may be used in the design of new CRT optimization studies.
Published: 2019

28. Optical Imaging of Ventricular Action Potentials in a Torso Tank: A New Platform for Non-Invasive Electrocardiographic Imaging Validation

Author: Laura R. Bear, Richard D. Walton, Emma Abell, Yves Coudière, Michel Haissaguerre, Olivier Bernus, Rémi Dubois, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], CHU Bordeaux [Bordeaux], This work was supported by the French National Research Agency (ANR-10-IAHU04-LIRYC), La Fondation Coeur et Artères (FCA14T2), the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013), and the Leducq Foundation transatlantic network of excellence RHYTHM transatlantic network (16CVD02)., Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)
Subjects: Materials science, Benign early repolarization, torso tank, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Physiology, 030204 cardiovascular system & hematology, lcsh:Physiology, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Optical mapping, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging, medicine, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Fluoroscopy, Repolarization, Sinus rhythm, 030212 general & internal medicine, Image resolution, ComputingMilieux_MISCELLANEOUS, Original Research, validation, lcsh:QP1-981, medicine.diagnostic_test, [INFO.INFO-NA]Computer Science [cs]/Numerical Analysis [cs.NA], Torso, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, optical mapping, medicine.anatomical_structure, [INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV], Electrocardiographic imaging, inverse problem, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], ECGI, [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], Biomedical engineering
Abstract: Background: Non-invasive electrocardiographic imaging (ECGI) is a promising tool to provide high-resolution panoramic imaging of cardiac electrical activity noninvasively from body surface potential measurements. Current experimental methods for ECGI validation are limited to comparison with unipolar electrograms and the relatively low spatial resolution of cardiac mapping arrays. We aim to develop a novel experimental set up combining a human shaped torso tank with high-resolution optical mapping allowing the validation of ECGI reconstructions. Methods: Langendorff-perfused pig hearts (n = 3) were suspended in a human torso-shaped tank, with the left anterior descending artery (LAD) cannulated on a separate perfusion. Electrical signals were recorded from an 108-electrode epicardial sock and 128 electrodes embedded in the tank surface. Simultaneously, optical mapping of the heart was performed through the anterior surface of the tank. Recordings were made in sinus rhythm and ventricular pacing (n = 55), with activation and repolarization heterogeneities induced by perfusion of hot and cold solutions as well as Sotalol through the LAD. Fluoroscopy provided 3D cardiac and electrode geometries in the tank that were transformed to the 2D optical mapping window using an optimization algorithm. Epicardial unipolar electrograms were reconstructed from torso potentials using ECGI and validated using optical activation and repolarization maps. Results: The transformation and alignment of the 3D geometries onto the 2D optical mapping window was good with an average correlation of 0.87 ± 0.10 and error of 7.7 ± 3.1 ms with activation derived from the sock. The difference in repolarization times were more substantial (error = 17.4 ± 3.7 ms) although the sock and optical repolarization patterns themselves were very similar (correlation = 0.83 ± 0.13). Validation of ECGI reconstructions revealed ECGI accurately captures the pattern of activation (correlation = 0.79 ± 0.11) and identified regions of late and/or early repolarization during different perfusions through LAD. ECGI also correctly demonstrated gradients in both activation and repolarization, although in some cases these were under or over-estimated or shifted slightly in space. Conclusion: A novel experimental setup has been developed, combining a human-shaped torso tank with optical mapping, which can be effectively used in the validation of ECGI techniques; including the reconstruction of activation and repolarization patterns and gradients.
Published: 2019

29. Information theory to tachycardia therapy: electrogram entropy predicts diastolic microstructure of reentrant ventricular tachycardia

Author: Stéphane Massé, Karl Magtibay, Mohammadali Beheshti, Abhishek Bhaskaran, Edward J. Vigmond, Kumaraswamy Nanthakumar, Eugene Downar, Sachin Nayyar, Yawer Saeed, Timothy Liang, Toronto General Hospital Research Institute [Canada] (TGHRI), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], University Health Network, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)
Subjects: 0301 basic medicine, Tachycardia, medicine.medical_specialty, Substrate mapping, Physiology, Entropy, Diastole, Information Theory, 030204 cardiovascular system & hematology, Information theory, Ventricular tachycardia, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Heart Rate, Physiology (medical), Internal medicine, medicine, Entropy (information theory), Humans, ComputingMilieux_MISCELLANEOUS, Physics, Models, Cardiovascular, medicine.disease, Myocardial Contraction, 030104 developmental biology, Reentrancy, Cardiology, Tachycardia, Ventricular, [SDV.IB]Life Sciences [q-bio]/Bioengineering, medicine.symptom, Cardiology and Cardiovascular Medicine, Electrophysiologic Techniques, Cardiac
Abstract: There is no known strategy to differentiate which multicomponent electrograms in sinus rhythm maintain reentrant ventricular tachycardia (VT). Low entropy in the voltage breakdown of a multicomponent electrogram can localize conditions suitable for reentry but has not been validated against the classic VT activation mapping. We examined whether low entropy in a late and diversely activated ventricular scar region characterizes and differentiates the diastolic path of VT and represents protected tissue channels devoid of side branches. Intraoperative bipolar electrogram (BiEGM) activation and entropy maps were obtained during sinus rhythm in 17 patients with ischemic cardiomyopathy and compared with diastolic activation paths of VT (total of 39 VTs). Mathematical modeling of a zigzag main channel with side branches was also used to further validate structural representation of low entropy in the ventricular scar. A median of one region per patient (range: 1–2 regions) was identified in sinus rhythm, in which BiEGMwith the latest mean activation time and adjacent minimum entropy were assembled together in a high-activation dispersion region. These regions accurately recognized diastolic paths of 34 VTs, often to multiple inducible VTs within a single individual arrhythmogenic region. In mathematical modeling, side branching from the main channel had a strong influence on the BiEGMcomposition along the main channel. The BiEGMobtained from a long unbranched channel had the lowest entropy compared with those with multiple side branches. In conclusion, among a population of multicomponent sinus electrograms, those that demonstrate low entropy and are delayed colocalize to critical long-protected channels of VT. This information is pertinent for planning VT ablation in sinus rhythm.NEW & NOTEWORTHY Entropy is a measure to quantify breakdown in information. Electrograms from a protected tissue channel can only possess a few states in their voltage and thus less information. In contrast, current-load interactions from side branches in unprotected channels introduce a number of dissimilar voltage deflections and thus high information. We compare here a mapping approach based on entropy against a rigorous reference standard of activation mapping during VT and entropy was assessed in sinus rhythm.
Published: 2019

30. Fibrillation Patterns Creep and Jump in a Detailed Three-Dimensional Model of the Human Atria

Author: Ali Gharaviri, Simone Pezzuto, Alain Vinet, Mark Potse, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Institut de génie biomédical [Montreal] (IGB), Université de Montréal (UdeM), Center for Computational Medicine in Cardiology [Lugano], Università della Svizzera italiana = University of Italian Switzerland (USI), This work was granted access to HPC resources of CINES under GENCI allocation 2019-A0050307379, Yves Coudière, Valéry Ozenne, Edward Vigmond, Nejib Zemzemi, ANR-10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Electroanatomic mapping, medicine.medical_specialty, Materials science, 030204 cardiovascular system & hematology, 03 medical and health sciences, 0302 clinical medicine, Computer model, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Internal medicine, medicine, [NLIN]Nonlinear Sciences [physics], 030212 general & internal medicine, Recurrence plot, Fibrillation, food and beverages, Atrial fibrillation, Reentry, medicine.disease, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Creep, Jump, Cardiology, [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], medicine.symptom, Three dimensional model
Abstract: International audience; Activation mapping in animal models of atrial fibrillation (AF) has shown that activation patterns can repeat for several cycles and then be followed by different changing or repetitive patterns. Subsequent clinical studies have suggested a similar type of activity in human AF. Our purpose was to investigate whether a computer model of human AF can reproduce this behavior. We used a three-dimensional model of the human atria consisting of 0.2-mm volumetric elements with a detailed representation of bundle structures and fiber orientations. Propagating activation was simulated over 9 seconds with a monodomain reaction-diffusion model using human atrial membrane dynamics. AF was induced by rapid pacing. Pattern recurrence was quantified using a similarity measure based on transmembrane voltage at 1000 uniformly distributed points in the model. Recurrence plots demonstrated a continuous evolution of patterns, but the speed of evolution varied considerably. Groups of upto 15 similar cycles could be recognized, separated by rapid changes. In a few cases truly periodic patterns developed, which were related to macroscopic anatomical reentry. The drivers of non-periodic patterns could not be clearly identified. For example, a spiral wave could appear or disappear without an obvious impact on the similarity between cycles. We conclude that our model can indeed reproduce strong variations in similarity between subsequent cycles, but true periodicity only in case of anatomical reentry.
Published: 2019

31. Acetylcholine Delays Atrial Activation to Facilitate Atrial Fibrillation

Author: Jason D. Bayer, Bastiaan J. Boukens, Sébastien P. J. Krul, Caroline H. Roney, Antoine H. G. Driessen, Wouter R. Berger, Nicoline W. E. van den Berg, Arie O. Verkerk, Edward J. Vigmond, Ruben Coronel, Joris R. de Groot, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Academic Medical Center - Academisch Medisch Centrum [Amsterdam] (AMC), University of Amsterdam [Amsterdam] (UvA), King‘s College London, Medical Biology, ACS - Amsterdam Cardiovascular Sciences, Cardiology, Cardiothoracic Surgery, Graduate School, ACS - Pulmonary hypertension & thrombosis, ACS - Atherosclerosis & ischemic syndromes, ACS - Heart failure & arrhythmias, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], and ANR-16-CE19-0009,WAYLESS,Stimulation de surface étendue à faible intensité (WAYLESS): une nouvelle thérapie pour terminer les arythmies cardiaques létales(2016)
Subjects: 0301 basic medicine, computational modeling, medicine.medical_specialty, conduction, Physiology, [SDV]Life Sciences [q-bio], 030204 cardiovascular system & hematology, Conduction, lcsh:Physiology, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Fibrosis, Physiology (medical), Internal medicine, Atria, medicine, Myocyte, fibrillation, Original Research, Fibrillation, Membrane potential, lcsh:QP1-981, Chemistry, fibrosis, Atrial fibrillation, Computational modeling, Reentry, medicine.disease, musculoskeletal system, acetylcholine, Acetylcholine, 030104 developmental biology, atria, Cardiology, cardiovascular system, medicine.symptom, Ex vivo, medicine.drug
Abstract: Background: Acetylcholine (ACh) shortens action potential duration (APD) in human atria. APD shortening facilitates atrial fibrillation (AF) by reducing the wavelength for reentry. However, the influence of ACh on electrical conduction in human atria and its contribution to AF are unclear, particularly when combined with impaired conduction from interstitial fibrosis.Objective: To investigate the effect of ACh on human atrial conduction and its role in AF with computational, experimental, and clinical approaches.Methods: S1S2 pacing (S1 = 600 ms and S2 = variable cycle lengths) was applied to the following human AF computer models: a left atrial appendage (LAA) myocyte to quantify the effects of ACh on APD, maximum upstroke velocity (Vmax), and resting membrane potential (RMP); a monolayer of LAA myocytes to quantify the effects of ACh on conduction; and 3) an intact left atrium (LA) to determine the effects of ACh on arrhythmogenicity. Heterogeneous ACh and interstitial fibrosis were applied to the monolayer and LA models. To corroborate the simulations, APD and RMP from isolated human atrial myocytes were recorded before and after 0.1 μM ACh. At the tissue level, LAAs from AF patients were optically mapped ex vivo using Di-4-ANEPPS. The difference in total activation time (AT) was determined between AT initially recorded with S1 pacing, and AT recorded during subsequent S1 pacing without (n = 6) or with (n = 7) 100 μM ACh.Results: In LAA myocyte simulations, S1 pacing with 0.1 μM ACh shortened APD by 41 ms, hyperpolarized RMP by 7 mV, and increased Vmax by 27 mV/ms. In human atrial myocytes, 0.1 μM ACh shortened APD by 48 ms, hyperpolarized RMP by 3 mV, and increased Vmax by 6 mV/ms. In LAA monolayer simulations, S1 pacing with ACh hyperpolarized RMP to delay total AT by 32 ms without and 35 ms with fibrosis. This led to unidirectional conduction block and sustained reentry in fibrotic LA with heterogeneous ACh during S2 pacing. In AF patient LAAs, S1 pacing with ACh increased total AT from 39.3 ± 26 ms to 71.4 ± 31.2 ms (p = 0.036) compared to no change without ACh (56.7 ± 29.3 ms to 50.0 ± 21.9 ms, p = 0.140).Conclusion: In fibrotic atria with heterogeneous parasympathetic activation, ACh facilitates AF by shortening APD and slowing conduction to promote unidirectional conduction block and reentry.
Published: 2019

32. Effect of Na+-channel blockade on the three-dimensional substrate of atrial fibrillation in a model of endo-epicardial dissociation and transmural conduction

Author: Rolf Krause, Mark Potse, Sander Verheule, Ali Gharaviri, Nico H.L. Kuijpers, Ulrich Schotten, Angelo Auricchio, Jens Eckstein, Department of Physiology [Maastricht], Maastricht University [Maastricht], Center for Computational Medicine in Cardiology [Lugano], Università della Svizzera italiana = University of Italian Switzerland (USI), University Hospital Basel [Basel], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Cardiocentro Ticino [Lugano], Universität Zürich [Zürich] = University of Zurich (UZH), Fontys Hogeschool Toegepaste Natuurwetenschappen = Fontys University of Applied Sciences (FONTYS), This work was supported by grants from the European Union, the ITN Network AFibTrainNet, No. 675351, and the ERACoSysMED H2020 ERA-NET Cofound project Systems medicine for diagnosis and stratification of atrial fibrillation to US. This work was also supported by grants from the Swiss National Supercomputing Centre (CSCS) under project ID s668 and s778., European Project: 675351,H2020,H2020-MSCA-ITN-2015,AFib-TrainNet(2015), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, University of Zurich, Schotten, Ulrich, Fysiologie, RS: CARIM - R2 - Cardiac function and failure, Promovendi CD, RS: CARIM - R2.11 - Experimental atrial fibrillation, and Biomedische Technologie
Subjects: 0301 basic medicine, Time Factors, medicine.medical_treatment, Action Potentials, Sodium-channel block, 030204 cardiovascular system & hematology, Cardioversion, 2737 Physiology (medical), 0302 clinical medicine, Sodium channel blocker, Computer model, Heart Rate, TERMINATION, Sinus rhythm, Treatment Failure, Models, Cardiovascular, Atrial fibrillation, CARDIOVERSION, INSIGHTS, Transmural conduction, Cardiology, FLECAINIDE, SINUS RHYTHM, Cardiology and Cardiovascular Medicine, Three-dimensional, Anti-Arrhythmia Agents, Sodium Channel Blockers, medicine.drug, 030103 biophysics, medicine.medical_specialty, Sodium, chemistry.chemical_element, 610 Medicine & health, 11171 Cardiocentro Ticino, 2705 Cardiology and Cardiovascular Medicine, MECHANISMS, PERSISTENT, 03 medical and health sciences, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Internal medicine, medicine, Humans, Computer Simulation, Heart Atria, Flecainide, Atrium (architecture), business.industry, Sodium channel, Atrial Remodeling, medicine.disease, CONVERSION, Electrical dissociation, chemistry, business
Abstract: Aims Atrial fibrillation (AF) is a progressive arrhythmia characterized by structural alterations that increase its stability. Both clinical and experimental studies showed a concomitant loss of antiarrhythmic drug efficacy in later stages of AF. The mechanisms underlying this loss of efficacy are not well understood. We hypothesized that structural remodelling may explain this reduced efficacy by making the substrate more three-dimensional. To investigate this, we simulated the effect of sodium (Nathorn)-channel block on AF in a model of progressive transmural uncoupling. Methods and results In a computer model consisting of two cross-connected atrial layers, with realistic atrial membrane behaviour, structural remodelling was simulated by reducing the number of connections between the layers. 100% of endoepicardial connectivity represented a healthy atrium. At various degrees of structural remodelling, we assessed the effect of 60% sodium channel block on AF stability, endo-epicardial electrical activity dissociation (EED), and fibrillatory conduction pattern complexity quantified by number of waves, phase singularities (PSs), and transmural conduction ('breakthrough', BT). Sodium channel block terminated AF in non-remodelled but not in remodelled atria. The temporal excitable gap (EG) and AF cycle length increased at all degrees of remodelling when compared with control. Despite an increase of EED and EG, sodium channel block decreased the incidence of BT because of transmural conduction block. Sodium channel block decreased the number of waves and PSs in normal atrium but not in structurally remodelled atrium. Conclusion This simple atrial model explains the loss of efficacy of sodium channel blockers in terminating AF in the presence of severe structural remodelling as has been observed experimentally and clinically. Atrial fibrillation termination in atria with moderate structural remodelling in the presence of sodium channel block is caused by reduction of AF complexity. With more severe structural remodelling, sodium channel block fails to promote synchronization of the two layers of the model.
Published: 2018

33. Determinants of atrial bipolar voltage: Inter electrode distance and wavefront angle

Author: Kumaraswamy Nanthakumar, Abhishek Bhaskaran, Sachin Nayyar, Shouvik Haldar, Benedict Glover, Karl Magtibay, Edward J. Vigmond, Mohammadali Beheshti, Stéphane Massé, D. Curtis Deno, Andreu Porta-Sánchez, University Health Network, Centro Nacional de Investigaciones Cardiovasculares Carlos III [Madrid, Spain] (CNIC), Instituto de Salud Carlos III [Madrid] (ISC), Royal Brompton and Harefield NHS Foundation Trust, Queen's University [Kingston, Canada], Abbott, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: Materials science, Swine, Heart Ventricles, Cardiac scar, Action Potentials, Health Informatics, Healthy tissue, 030204 cardiovascular system & hematology, Cardiac modelling, 03 medical and health sciences, Electrocardiography, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Animals, Humans, Computer Simulation, Heart Atria, Bipolar voltage, Electrodes, Wavefront, Bidomain model, Models, Cardiovascular, Arrhythmias, Cardiac, Cardiac mapping, Computer Science Applications, Core (optical fiber), Electrode, Bipolar electrogram voltage, Electrode geometry, [SDV.IB]Life Sciences [q-bio]/Bioengineering, sense organs, Electrophysiologic Techniques, Cardiac, 030217 neurology & neurosurgery, Algorithms, Software, Voltage, Biomedical engineering
Abstract: Background Local bipolar electrogram (EGM) peak-to-peak voltage (Vpp) is currently used to characterise mapped myocardial substrate. However, how interelectrode distance and angle of wavefront incidence affect bipolar, Vpp values, in the current era of multi-electrode mapping is unknown. Objectives To elucidate the effects of tissue and electrode geometry on bipolar Vpp measurements, when mapping healthy versus diseased atrial regions. Methods A bidomain model of human atrial tissue was used to quantify the influence on Vpp values of various electrode configurations in healthy tissue, and tissue containing an unexcitable region. The orientation angle and interelectrode spacing of a surface bipole, and thickness and depth of the unexcitable core were serially varied. Results were validated with data obtained from isolated porcine hearts. Results In healthy tissue, bipolar Vpp values increased with increasing interelectrode spacing and plateaued beyond a spacing of approximately 4 mm. The bipolar Vpp values in healthy tissue were relatively less sensitive to wavefront orientation angle with large interelectrode spacing. In diseased tissue, on the contrary, with increasing interelectrode spacing, bipolar Vpp values increased linearly without a plateau and were more sensitive to orientation angle. The bipolar Vpp values decreased with increasing thickness of the scar, with larger relative decrease in small bipoles than larger ones. Bipolar Vpp values increased with a progressively intramural location of fixed-size scar and became less distinguishable from healthy tissue especially for smaller interelectrode spacings. Conclusions The scalable relationship established for interelectrode distances favour an electric-field-based assessment as opposed to traditional Vpp values as a tool for physiologically relevant measurement for mapping catheters with interelectrode spacing up to 4 mm. This will allow for universal assessment of myocardial health across catheters with varied spacing.
Published: 2018

34. Fibrosis and Conduction Abnormalities as Basis for Overlap of Brugada Syndrome and Early Repolarization Syndrome

Author: Bastiaan J. Boukens, Mark Potse, Ruben Coronel, Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam [Amsterdam] (UvA), Department of Medical Biology, Amsterdam University Medical Center, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), RHYTHM (Leducq 16CVD02): This work was supported by the French National Research Agency, grant reference ANR-10-IAHU04-LIRYC. Dutch Heart Foundation (2016T047). Simulations were performed on HPC resources of IDRIS under GENCI allocation x2015037379., ANR-10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, medicine.medical_specialty, conduction, Mechanism based, Review, 030204 cardiovascular system & hematology, Catalysis, lcsh:Chemistry, Inorganic Chemistry, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Cardiac Conduction System Disease, Heart Conduction System, Fibrosis, Internal medicine, Animals, Humans, Medicine, Ventricular outflow tract, Brugada syndrome, In patient, cardiovascular diseases, Physical and Theoretical Chemistry, lcsh:QH301-705.5, Molecular Biology, Spectroscopy, repolarization, EARLY REPOLARIZATION SYNDROME, Conduction abnormalities, business.industry, fibrosis, Organic Chemistry, early repolarization pattern, Arrhythmias, Cardiac, General Medicine, medicine.disease, Computer Science Applications, 030104 developmental biology, lcsh:Biology (General), lcsh:QD1-999, Cardiology, business, arrhythmias
Abstract: International audience; Brugada syndrome and early repolarization syndrome are both classified as J-wave syndromes, with a similar mechanism of arrhythmogenesis and with the same basis for genesis of the characteristic electrocardiographic features. The Brugada syndrome is now considered a conduction disorder based on subtle structural abnormalities in the right ventricular outflow tract. Recent evidence suggests structural substrate in patients with the early repolarization syndrome as well. We propose a unifying mechanism based on these structural abnormalities explaining both arrhythmogenesis and the electrocardiographic changes. In addition, we speculate that, with increasing technical advances in imaging techniques and their spatial resolution, these syndromes will be reclassified as structural heart diseases or cardiomyopathies.
Published: 2021

35. P-wave complexity in normal subjects and computer models

Author: Ulrich Schotten, Mark Potse, Nico H.L. Kuijpers, André C. Linnenbank, Pieter C. Dagnelie, Theo Lankveld, Stef Zeemering, Coen D.A. Stehouwer, Ronald M.A. Henry, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Cardiovascular Research Institute Maastricht (CARIM), Maastricht University [Maastricht], Department of Physiology [Maastricht], Academic Medical Center - Academisch Medisch Centrum [Amsterdam] (AMC), University of Amsterdam [Amsterdam] (UvA), A.C.L. was supported by the Dutch Technology Foundation STW under grant number 10959., Simulations were performed on an SGI Altix 4700 supercomputer at Université de Montréal, operated by Calcul Québec and Compute Canada, and financed by the Canada Foundation for Innovation (CFI), NanoQuébec, RMGA, and the Fonds de recherche du Québec - Nature et technologies (FRQ-NT)., European Project: 256493,EC:FP7:PEOPLE,FP7-PEOPLE-2009-RG,ASAF(2010), European Project: 261057,EC:FP7:HEALTH,FP7-HEALTH-2010-single-stage,EUTRAF(2010), Biomedische Technologie, Promovendi CD, Cardiologie, Fysiologie, RS: CAPHRI - R5 - Optimising Patient Care, Epidemiologie, RS: CARIM - R3.01 - Vascular complications of diabetes and the metabolic syndrome, Interne Geneeskunde, MUMC+: MA Interne Geneeskunde (3), MUMC+: HVC Pieken Maastricht Studie (9), RS: CARIM - R2.11 - Experimental atrial fibrillation, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], and Cardiology
Subjects: Adult, Male, Aging, 0206 medical engineering, P wave, 02 engineering and technology, Recording techniques, 030204 cardiovascular system & hematology, Classification of discontinuities, Interference (wave propagation), MESH: Signal Processing, Computer-Assisted, Sensitivity and Specificity, Electrocardiography, 03 medical and health sciences, 0302 clinical medicine, MESH: Computer Simulation, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, Heart Conduction System, Reference Values, medicine, Range (statistics), Humans, Computer Simulation, Heart Atria, Aged, Netherlands, Mathematics, Signal processing, medicine.diagnostic_test, Mathematical analysis, Models, Cardiovascular, Reproducibility of Results, MESH: Cardiovascular Diseases, Computer models, Middle Aged, 020601 biomedical engineering, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Electrocardiogram, Noise, Female, [SDV.IB]Life Sciences [q-bio]/Bioengineering, Electrical conduction system of the heart, Interatrial block, Filtering, Cardiology and Cardiovascular Medicine
Abstract: International audience; Background: P waves reported in electrocardiology literature uniformly appear smooth. Computer simulation and signal analysis studies have shown much more complex shapes. Objective: We systematically investigated P-wave complexity in normal volunteers using high-fidelity electrocardiographic techniques without filtering. Methods: We recorded 5-min multichannel ECGs in 16 healthy volunteers. Noise and interference were reduced by averaging over 300 beats per recording. In addition, normal P waves were simulated with a realistic model of the human atria. Results: Measured P waves had an average of 4.1 peaks (range 1–10) that were reproducible between recordings. Simulated P waves demonstrated similar complexity, which was related to structural discontinuities in the computer model of the atria. Conclusion: The true shape of the P wave is very irregular and is best seen in ECGs averaged over many beats.
Published: 2016
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36. Patient-derived models link re-entrant driver localization in atrial fibrillation to fibrosis spatial pattern

Author: Patrick M. Boyle, Michel Haïssaguerre, Hubert Cochet, Pierre Jaïs, Mélèze Hocini, Erica L. Schwarz, Edward J. Vigmond, Rémi Dubois, Natalia A. Trayanova, Kaitlyn N. Whyte, Sohail Zahid, Johns Hopkins University (JHU), AgroParisTech, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: Male, 0301 basic medicine, Pathology, Physiology, Action Potentials, 030204 cardiovascular system & hematology, Re-entrant drivers, Electrocardiography, 0302 clinical medicine, Heart Rate, Fibrosis, Patient-derived atrial models, Atrial Fibrillation, Medicine, medicine.diagnostic_test, Cardiac Pacing, Artificial, Models, Cardiovascular, Atrial fibrillation, Middle Aged, Magnetic Resonance Imaging, Editorial, Cardiovascular Diseases, Persistent atrial fibrillation, cardiovascular system, Female, [SDV.IB]Life Sciences [q-bio]/Bioengineering, Electrophysiologic Techniques, Cardiac, Cardiology and Cardiovascular Medicine, Adult, medicine.medical_specialty, Cardiac-Gated Imaging Techniques, 03 medical and health sciences, Imaging, Three-Dimensional, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Image Interpretation, Computer-Assisted, Heart rate, Humans, Computer Simulation, In patient, Heart Atria, cardiovascular diseases, business.industry, Magnetic resonance imaging, Atrial Remodeling, medicine.disease, 030104 developmental biology, Computational modelling, Re entrant, ORIGINAL ARTICLES, business
Abstract: Aims The mechanisms underlying persistent atrial fibrillation (AF) in patients with atrial fibrosis are poorly understood. The goal of this study was to use patient-derived atrial models to test the hypothesis that AF re-entrant drivers (RDs) persist only in regions with specific fibrosis patterns. Methods and results Twenty patients with persistent AF (PsAF) underwent late gadolinium-enhanced MRI to detect the presence of atrial fibrosis. Segmented images were used to construct personalized 3D models of the fibrotic atria with biophysically realistic atrial electrophysiology. In each model, rapid pacing was applied to induce AF. AF dynamics were analysed and RDs were identified using phase mapping. Fibrosis patterns in RD regions were characterized by computing maps of fibrosis density (FD) and entropy (FE). AF was inducible in 13/20 models and perpetuated by few RDs (2.7 ± 1.5) that were spatially confined (trajectory of phase singularities: 7.6 ± 2.3 mm). Compared with the remaining atrial tissue, regions where RDs persisted had higher FE (IQR: 0.42–0.60 vs. 0.00–0.40, P < 0.05) and FD (IQR: 0.59–0.77 vs. 0.00–0.33, P < 0.05). Machine learning classified RD and non-RD regions based on FD and FE and identified a subset of fibrotic boundary zones present in 13.8 ± 4.9% of atrial tissue where 83.5 ± 2.4% of all RD phase singularities were located. Conclusion Patient-derived models demonstrate that AF in fibrotic substrates is perpetuated by RDs persisting in fibrosis boundary zones characterized by specific regional fibrosis metrics (high FE and FD). These results provide new insights into the mechanisms that sustain PsAF and could pave the way for personalized, MRI-based management of PsAF.
Published: 2016

37. Abnormal Lymphatic Channels Detected by T2-Weighted MR Imaging as a Substrate for Ventricular Arrhythmia in HCM

Author: Raymond Yee, James A. White, Edward Tweedie, Donald G. Welsh, Sebastien X Joncas, Carmen P Lydell, David Scholl, Edward J. Vigmond, Yoko Mikami, Martin Rajchl, Louis Kolman, Andrew G Howarth, John Stirrat, University of Calgary, Robarts Research Institute [Canada], University of Western Ontario (UWO), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Hôtel-Dieu de Québec, Imperial College London, Foothills Medical Centre, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: medicine.medical_specialty, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, medicine.medical_treatment, Cardiomyopathy, 030204 cardiovascular system & hematology, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Fibrosis, Internal medicine, Biopsy, Medicine, Radiology, Nuclear Medicine and imaging, cardiovascular diseases, ComputingMilieux_MISCELLANEOUS, Heart transplantation, medicine.diagnostic_test, business.industry, Hypertrophic cardiomyopathy, Magnetic resonance imaging, medicine.disease, Lymphatic system, cardiovascular system, Cardiology, Myocardial fibrosis, Cardiology and Cardiovascular Medicine, business
Abstract: Hypertrophic cardiomyopathy (HCM) is a common genetic disorder associated with elevated risk of lethal ventricular arrhythmias. While the absence of myocardial fibrosis on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) appears to identify lower risk individuals, approximately two
Published: 2016

38. Beat-to-beat P-wave morphological variability in patients with paroxysmal atrial fibrillation: an in silico study

Author: Ali Gharaviri, Ulrich Schotten, Angelo Auricchio, Mark Potse, Rolf Krause, Maria Luce Caputo, François Regoli, Giulio Conte, Simone Pezzuto, Center for Computational Medicine in Cardiology [Lugano], Università della Svizzera italiana = University of Italian Switzerland (USI), Institute of Computational Science (ICS), Department of Physiology [Maastricht], Maastricht University [Maastricht], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Cardiocentro Ticino [Lugano], Universität Zürich [Zürich] = University of Zurich (UZH), This work was also supported by the Swiss National Supercomputing Centre (CSCS) under project ID s778., University of Zurich, Pezzuto, Simone, Promovendi CD, Fysiologie, RS: CARIM - R2.11 - Experimental atrial fibrillation, Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest
Subjects: Time Factors, medicine.medical_treatment, Action Potentials, 030204 cardiovascular system & hematology, Cosine distance, Correlation, INITIATION, Electrocardiography, 0302 clinical medicine, 2737 Physiology (medical), Heart Rate, Atrial Fibrillation, Medicine, ComputingMilieux_MISCELLANEOUS, CATHETER ABLATION, medicine.diagnostic_test, Paroxysmal atrial fibrillation, Models, Cardiovascular, Magnetic Resonance Imaging, Inhomogeneous conduction, medicine.anatomical_structure, Cardiology and Cardiovascular Medicine, Biological system, Electrophysiologic Techniques, Cardiac, MRI, P-wave variability, In silico, MODELS, P-wave morphology, Beat (acoustics), Catheter ablation, 610 Medicine & health, 11171 Cardiocentro Ticino, 2705 Cardiology and Cardiovascular Medicine, MECHANISMS, 03 medical and health sciences, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Heart rate, Humans, Computer Simulation, Heart Atria, Atrium (architecture), business.industry, Sinoatrial node, Fibrosis, TISSUE, LINK, business, 030217 neurology & neurosurgery
Abstract: Aims P-wave beat-to-beat morphological variability can identify patients prone to paroxysmal atrial fibrillation (AF). To date, no computational study has been carried out to mechanistically explain such finding. The aim of this study was to provide a pathophysiological explanation, by using a computer model of the human atria, of the correlation between P-wave beat-to-beat variability and the risk of AF.Methods and results A physiological variability in the earliest activation site (EAS), on a beat-to-beat basis, was introduced into a computer model of the human atria by randomizing the EAS location. A methodology for generating multi-scale, spatially-correlated regions of heterogeneous conduction was developed. P-wave variability in the presence of such regions was compared with a control case. Simulations were performed with an eikonal model, for the activation map, and with the lead field approach, for P-wave computation. The methodology was eventually compared with a reference monodomain simulation. A total of 60 P-waves were simulated for each sinus node exit location (12 in total), and for each of the 15 patterns of heterogeneous conduction automatically generated by the model. A P-wave beat-to-beat variability was observed in all cases. Variability was significantly increased in presence of heterogeneous slow conducting regions, up to two-fold the variability in the control case. P-wave variability increased non-linearly with respect to the EAS variability and total area of slow conduction. Distribution of the heterogeneous conduction was more effective in increasing the variability when it surrounded the EAS locations and the fast conducting bundles. P-waves simulated by the eikonal approach compared excellently with the monodomain-based ones.Conclusion P-wave variability in patients with paroxysmal AF could be explained by a variability in sinoatrial node exit location in combination with slow conducting regions.
Published: 2018

39. New insights on the cardiac safety factor: Unraveling the relationship between conduction velocity and robustness of propagation

Author: Edward J. Vigmond, Thomas Desplantez, Natalia A. Trayanova, William H. Franceschi, Claudia Hawks, Marion Constantin, Patrick M. Boyle, Johns Hopkins University (JHU), Centre de recherche Cardio-Thoracique de Bordeaux [Bordeaux] (CRCTB), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut National de la Santé et de la Recherche Médicale (INSERM), Universidad de Navarra [Pamplona] (UNAV), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Vigmond, Edward, Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: 0301 basic medicine, Source-sink mismatch, Conduction velocity, [SDV]Life Sciences [q-bio], Cardiac electrophysiology, Action Potentials, 030204 cardiovascular system & hematology, Cardiac excitability, Synthetic data, Nerve conduction velocity, Article, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Robustness (computer science), Heart Rate, Range (statistics), Animals, Humans, Myocytes, Cardiac, Molecular Biology, Cardiac safety factor, Physics, [SDV.IB] Life Sciences [q-bio]/Bioengineering, Computational model, Sodium channel, Myocardium, Models, Cardiovascular, Cardiac arrhythmia, Arrhythmias, Cardiac, Thermal Conductivity, Thermal conduction, Fibrosis, Myocardial Contraction, [SDV.MHEP.CSC] Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Electrophysiological Phenomena, [SDV] Life Sciences [q-bio], 030104 developmental biology, Heart Block, [SDV.IB]Life Sciences [q-bio]/Bioengineering, Cardiology and Cardiovascular Medicine, Biological system
Abstract: International audience; Cardiac conduction disturbances are linked with arrhythmia development. The concept of safety factor (SF) has been derived to describe the robustness of conduction, but the usefulness of this metric has been constrained by several limitations. For example, due to the difficulty of measuring the necessary input variables, SF calculations have only been applied to synthetic data. Moreover, quantitative validation of SF is lacking; specifically, the practical meaning of particular SF values is unclear, aside from the fact that propagation failure (i.e., conduction block) is characterized by SF
Published: 2018

40. Localized Structural Alterations Underlying a Subset of Unexplained Sudden Cardiac Death

Author: Ruben Coronel, Stéphane Puyo, Michael J. Ackerman, Mélèze Hocini, Grégoire Massoullié, Pierre Jaïs, Louis Labrousse, Masateru Takigawa, Josselin Duchateau, Frederic Sacher, Olivier Piot, Sylvain Ploux, Jean-Jacques Schott, Xavier Pillois, Thomas Pambrun, Nicolas Derval, Estelle Gandjbakhch, Christophe Leclerc, Nicolas Klotz, Rémi Dubois, Edward J. Vigmond, Jean-Sylvain Hermida, Olivier Bernus, Philippe Ritter, Ruairidh Martin, David J. Tester, Arnaud Denis, Philippe Maury, Koonlawee Nademanee, Pierre Bordachar, David Benoist, Corentin Dallet, Michel Haïssaguerre, Richard D. Walton, Jean-Luc Pasquié, Ghassen Cheniti, Solena Le Scouarnec, Mark Potse, Hubert Cochet, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Université de Bordeaux (UB), CHU Bordeaux [Bordeaux], Centre de recherche Cardio-Thoracique de Bordeaux [Bordeaux] (CRCTB), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Haut-Lévêque [CHU Bordeaux], unité de recherche de l'institut du thorax UMR1087 UMR6291 (ITX), Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut du thorax, Université de Nantes (UN)-IFR26-Institut National de la Santé et de la Recherche Médicale (INSERM), Mayo Clinic, Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), Physiologie & médecine expérimentale du Cœur et des Muscles [U 1046] (PhyMedExp), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Traitement du Signal et de l'Image (LTSI), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Santé et de la Recherche Médicale (INSERM), CHU Amiens-Picardie, Unité de Recherche sur les Maladies Cardiovasculaires, du Métabolisme et de la Nutrition = Institute of cardiometabolism and nutrition (ICAN), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Sorbonne Université (SU), CHU Toulouse [Toulouse], Bibliothèque interuniversitaire de santé (BIUS), Université Paris Descartes - Paris 5 (UPD5), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], White Memorial Medical Center, Cardiology, ACS - Heart failure & arrhythmias, Unité de recherche de l'institut du thorax (ITX-lab), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN), Université de Rennes (UR)-Institut National de la Santé et de la Recherche Médicale (INSERM), Unité de Recherche sur les Maladies Cardiovasculaires, du Métabolisme et de la Nutrition = Research Unit on Cardiovascular and Metabolic Diseases (ICAN), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Institut de Cardiométabolisme et Nutrition = Institute of Cardiometabolism and Nutrition [CHU Pitié Salpêtrière] (IHU ICAN), CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Centre Hospitalier Universitaire de Toulouse (CHU Toulouse), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and MORNET, Dominique
Subjects: Male, Time Factors, medicine.medical_treatment, [SDV]Life Sciences [q-bio], Action Potentials, 030204 cardiovascular system & hematology, Sudden cardiac death, 0302 clinical medicine, Heart Rate, Risk Factors, Cause of Death, 030212 general & internal medicine, Epicardial mapping, Incidence, Cardiac Pacing, Artificial, Progression-Free Survival, 3. Good health, [SDV] Life Sciences [q-bio], ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Cardiology, Female, Catheter ablation, Electrophysiologic Techniques, Cardiac, Cardiology and Cardiovascular Medicine, Adult, medicine.medical_specialty, Adolescent, Purkinje Fibers, Young Adult, 03 medical and health sciences, Predictive Value of Tests, Physiology (medical), Internal medicine, medicine, Humans, Ventricular fibrillation, Endocardium, business.industry, Original Articles, medicine.disease, Death, Sudden, Cardiac, business
Abstract: Supplemental Digital Content is available in the text., Background: Sudden cardiac death because of ventricular fibrillation (VF) is commonly unexplained in younger victims. Detailed electrophysiological mapping in such patients has not been reported. Methods: We evaluated 24 patients (29±13 years) who survived idiopathic VF. First, we used multielectrode body surface recordings to identify the drivers maintaining VF. Then, we analyzed electrograms in the driver regions using endocardial and epicardial catheter mapping during sinus rhythm. Established electrogram criteria were used to identify the presence of structural alterations. Results: VF occurred spontaneously in 3 patients and was induced in 16, whereas VF was noninducible in 5. VF mapping demonstrated reentrant and focal activities (87% versus 13%, respectively) in all. The activities were dominant in one ventricle in 9 patients, whereas they had biventricular distribution in others. During sinus rhythm areas of abnormal electrograms were identified in 15/24 patients (62.5%) revealing localized structural alterations: in the right ventricle in 11, the left ventricle in 1, and both in 3. They covered a limited surface (13±6 cm2) representing 5±3% of the total surface and were recorded predominantly on the epicardium. Seventy-six percent of these areas were colocated with VF drivers (P
Published: 2018

41. Variability in pulmonary vein electrophysiology and fibrosis determines arrhythmia susceptibility and dynamics

Author: Rémi Dubois, Pierre Jaïs, Jason D. Bayer, Edward J. Vigmond, Hubert Cochet, Marianna Meo, Caroline H. Roney, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], ANR-16-CE17-0005,GENMSMD,Dissection génétique de la Susceptibilité Mendélienne aux infections mycobactériennes chez l'homme(2016), and ANR-16-CE19-0009,WAYLESS,Stimulation de surface étendue à faible intensité (WAYLESS): une nouvelle thérapie pour terminer les arythmies cardiaques létales(2016)
Subjects: 0301 basic medicine, medicine.medical_specialty, QH301-705.5, medicine.medical_treatment, Action Potentials, Catheter ablation, 030204 cardiovascular system & hematology, Nerve conduction velocity, Pulmonary vein, 03 medical and health sciences, Cellular and Molecular Neuroscience, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Fibrosis, Internal medicine, Atrial Fibrillation, Genetics, medicine, Humans, Computer Simulation, Heart Atria, Biology (General), Molecular Biology, Ecology, Evolution, Behavior and Systematics, Endocardium, Ecology, Cardiac electrophysiology, business.industry, Models, Cardiovascular, Atrial fibrillation, Reentry, medicine.disease, 030104 developmental biology, Computational Theory and Mathematics, Pulmonary Veins, Modeling and Simulation, Cardiology, Catheter Ablation, cardiovascular system, Cardiac Electrophysiology, business
Abstract: International audience; Success rates for catheter ablation of persistent atrial fibrillation patients are currently low; however, there is a subset of patients for whom electrical isolation of the pulmonary veins alone is a successful treatment strategy. It is difficult to identify these patients because there are a multitude of factors affecting arrhythmia susceptibility and maintenance, and the individual contributions of these factors are difficult to determine clinically. We hypothesised that the combination of pulmonary vein (PV) electrophysiology and atrial body fibrosis determine driver location and effectiveness of pulmonary vein isolation (PVI). We used bilayer biatrial computer models based on patient geometries to investigate the effects of PV properties and atrial fibrosis on arrhythmia inducibility, maintenance mechanisms, and the outcome of PVI. Short PV action potential duration (APD) increased arrhythmia susceptibility, while longer PV APD was found to be protective. Arrhythmia inducibility increased with slower conduction velocity (CV) at the LA/PV junction, but not for cases with homogeneous CV changes or slower CV at the distal PV. Phase singularity (PS) density in the PV region for cases with PV fibrosis was increased. Arrhythmia dynamics depend on both PV properties and fibrosis distribution, varying from meandering rotors to PV reentry (in cases with baseline or long APD), to stable rotors at regions of high fibrosis density. Measurement of fibrosis and PV properties may indicate patient specific susceptibility to AF initiation and maintenance. PV PS density before PVI was higher for cases in which AF terminated or converted to a macroreentry; thus, high PV PS density may indicate likelihood of PVI success.
Published: 2018

42. Mechano-electric finite element model of the left atrium

Author: Alessandro Satriano, Elena S. Di Martino, David Schwartzman, Edward J. Vigmond, University of Calgary, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), University of Pittsburgh School of Medicine, Pennsylvania Commonwealth System of Higher Education (PCSHE), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: Cardiac function curve, medicine.medical_specialty, Swine, 0206 medical engineering, Finite Element Analysis, Left atrium, Health Informatics, Blood volume, 02 engineering and technology, 030204 cardiovascular system & hematology, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Heart Conduction System, Internal medicine, medicine, Animals, Sinus rhythm, Computer Simulation, Mitral annulus, Heart Atria, cardiovascular diseases, Physics, Computational model, Models, Cardiovascular, Atrial Function, 020601 biomedical engineering, Finite element method, Computer Science Applications, Biomechanical Phenomena, Preload, medicine.anatomical_structure, Mechano-electric coupling, Cardiology, cardiovascular system, [SDV.IB]Life Sciences [q-bio]/Bioengineering, Tomography, X-Ray Computed, Pressure generation, Algorithms
Abstract: International audience; Mechanical stretch plays a major role in modulating atrial function, being responsible for beat-by-beat responses to changes in chamber preload, enabling a prompt regulation of cardiac function. Mechano-electric coupling (MEC) operates through many mechanisms and has many targets, making it experimentally difficult to isolate causes and effects especially under sinus conditions where effects are more transient and subtle. Therefore, modelling is a powerful tool to help understand the role of MEC with respect to the atrial electromechanical interaction. We propose a cellular-based computational model of the left atrium that includes a strongly coupled MEC component and mitral flow component to account for correct pressure generation in the atrial chamber as a consequence of blood volume and contraction. The method was applied to a healthy porcine left atrium. Results of the strongly coupled simulation show that strains are higher in the areas adjacent to the mitral annulus, the rim of the appendage, around the pulmonary venous trunks and at the location of the Bachmann's bundle, approximately between the mitral annulus and the region where the venous tissue transitions into atrial. These are regions where arrhythmias are likely to originate. The role of stretch-activated channels was very small for sinus rhythm for the single cardiac beat simulation, although tension development was very sensitive to stretch. The method could be applied to investigate potential therapeutic interventions acting on the mechano-electrical properties of the left atrium.
Published: 2018

43. Comparing Reentrant Drivers Predicted by Image-Based Computational Modeling and Mapped by Electrocardiographic Imaging in Persistent Atrial Fibrillation

Author: Patrick M. Boyle, Joe B. Hakim, Sohail Zahid, William H. Franceschi, Michael J. Murphy, Edward J. Vigmond, Rémi Dubois, Michel Haïssaguerre, Mélèze Hocini, Pierre Jaïs, Natalia A. Trayanova, Hubert Cochet, Johns Hopkins University (JHU), Medical Research Council, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)
Subjects: 0301 basic medicine, medicine.medical_specialty, Physiology, medicine.medical_treatment, 030204 cardiovascular system & hematology, Ablation, lcsh:Physiology, 03 medical and health sciences, Fibrotic remodeling, 0302 clinical medicine, Text mining, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Internal medicine, medicine, Electrocardiographic mapping, Original Research, lcsh:QP1-981, medicine.diagnostic_test, business.industry, Magnetic resonance imaging, Atrial fibrillation, Computational modeling, medicine.disease, 030104 developmental biology, Positive response, Electrocardiographic imaging, Persistent atrial fibrillation, Cardiology, [SDV.IB]Life Sciences [q-bio]/Bioengineering, business, Image based, Reentrant drivers
Abstract: International audience; Electrocardiographic mapping (ECGI) detects reentrant drivers (RDs) that perpetuate arrhythmia in persistent AF (PsAF). Patient-specific computational models derived from late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) identify all latent sites in the fibrotic substrate that could potentially sustain RDs, not just those manifested during mapped AF. The objective of this study was to compare RDs from simulations and ECGI (RDsim/RDECGI) and analyze implications for ablation. We considered 12 PsAF patients who underwent RDECGI ablation. For the same cohort, we simulated AF and identified RDsim sites in patient-specific models with geometry and fibrosis distribution from pre-ablation LGE-MRI. RDsim- and RDECGI-harboring regions were compared, and the extent of agreement between macroscopic locations of RDs identified by simulations and ECGI was assessed. Effects of ablating RDECGI/RDsim were analyzed. RDsim were predicted in 28 atrial regions (median [inter-quartile range (IQR)] = 3.0 [1.0; 3.0] per model). ECGI detected 42 RDECGI-harboring regions (4.0 [2.0; 5.0] per patient). The number of regions with RDsim and RDECGI per individual was not significantly correlated (R = 0.46, P = ns). The overall rate of regional agreement was fair (modified Cohen's κ0 statistic = 0.11), as expected, based on the different mechanistic underpinning of RDsim- and RDECGI. nineteen regions were found to harbor both RDsim and RDECGI, suggesting that a subset of clinically observed RDs was fibrosis-mediated. The most frequent source of differences (23/32 regions) between the two modalities was the presence of RDECGI perpetuated by mechanisms other than the fibrotic substrate. In 6/12 patients, there was at least one region where a latent RD was observed in simulations but was not manifested during clinical mapping. Ablation of fibrosis-mediated RDECGI (i.e., targets in regions that also harbored RDsim) trended toward a higher rate of positive response compared to ablation of other RDECGI targets (57 vs. 41%, P = ns). Our analysis suggests that RDs in human PsAF are at least partially fibrosis-mediated. Substrate-based ablation combining simulations with ECGI could improve outcomes.
Published: 2018

44. Wavelength and Fibrosis Affect Phase Singularity Locations During Atrial Fibrillation

Author: Mirabeau Saha, Caroline H. Roney, Jason D. Bayer, Marianna Meo, Hubert Cochet, Remi Dubois, Edward J. Vigmond, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], King‘s College London, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], and ANR-16-CE19-0009,WAYLESS,Stimulation de surface étendue à faible intensité (WAYLESS): une nouvelle thérapie pour terminer les arythmies cardiaques létales(2016)
Subjects: 0301 basic medicine, medicine.medical_specialty, Physiology, Left atrium, repolarization heterogeneity, Phase singularity, phase singularity mapping, 030204 cardiovascular system & hematology, lcsh:Physiology, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Fibrosis, Physiology (medical), Internal medicine, medicine, computer simulation, atrial fibrillation, Clinical imaging, Cycle length, lcsh:QP1-981, Chemistry, Atrial fibrillation, medicine.disease, Coupling (electronics), Potassium current, 030104 developmental biology, medicine.anatomical_structure, Cardiology
Abstract: International audience; The mechanisms underlying atrial fibrillation (AF), the most common sustained cardiac rhythm disturbance, remain elusive. Atrial fibrosis plays an important role in the development of AF and rotor dynamics. Both electrical wavelength (WL) and the degree of atrial fibrosis change as AF progresses. However, their combined effect on rotor core location remains unknown. The aim of this study was to analyze the effects of WL change on rotor core location in both fibrotic and non-fibrotic atria. Three patient specific fibrosis distributions (total fibrosis content: 16.6, 22.8, and 19.2%) obtained from clinical imaging data of persistent AF patients were incorporated in a bilayer atrial computational model. Fibrotic effects were modeled as myocyte-fibroblast coupling + conductivity remodeling; structural remodeling; ionic current changes + conductivity remodeling; and combinations of these methods. To change WL, action potential duration (APD) was varied from 120 to 240ms, representing the range of clinically observed AF cycle length, by modifying the inward rectifier potassium current (IK1) conductance between 80 and 140% of the original value. Phase singularities (PSs) were computed to identify rotor core locations. Our results show that IK1 conductance variation resulted in a decrease of APD and WL across the atria. For large WL in the absence of fibrosis, PSs anchored to regions with high APD gradient at the center of the left atrium (LA) anterior wall and near the junctions of the inferior pulmonary veins (PVs) with the LA. Decreasing the WL induced more PSs, whose distribution became less clustered. With fibrosis, PS locations depended on the fibrosis distribution and the fibrosis implementation method. The proportion of PSs in fibrotic areas and along the borders varied with both WL and fibrosis modeling method: for patient one, this was 4.2-14.9% as IK1 varied for the structural remodeling representation, but 12.3-88.4% using the combination of structural remodeling with myocyte-fibroblast coupling. The degree and distribution of fibrosis and the choice of implementation technique had a larger effect on PS locations than the WL variation. Thus, distinguishing the fibrotic mechanisms present in a patient is important for interpreting clinical fibrosis maps to create personalized models.
Published: 2018

45. Numerical simulation of the fractional flow reserve (FFR)

Author: Keltoum Chahour, Rajae Aboulaich, Nejib Zemzemi, Abderrahmane Habbal, Cherif Abdelkhirane, Analysis and Control of Unsteady Models for Engineering Sciences (ACUMES), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Laboratoire d'Etudes et Recherche en Mathématiques Appliquées (LERMA), Ecole Mohammadia d'Ingénieurs (EMI), Laboratoire Jean Alexandre Dieudonné (JAD), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Clinique Maarif [Casablanca], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], This work has been supported by EPICARD cooperative research program, funded by the INRIA international laboratory LIRIMA., EPICARD, Laboratoire Jean Alexandre Dieudonné (LJAD), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), and Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest
Subjects: Fractional flow reserve, Computer simulation, Applied Mathematics, Infinitesimal, 010102 general mathematics, Mathematical analysis, Finite element solver, 030204 cardiovascular system & hematology, Atherosclerosis, 01 natural sciences, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Domain (mathematical analysis), [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], 03 medical and health sciences, Mathematics Subject Classification. 35Q30, 92C50, 97M60, 74F10, 0302 clinical medicine, Flow (mathematics), Generalized flow model, Modeling and Simulation, Fluid–structure interaction, Fluid-structure interaction, Quantitative assessment, 0101 mathematics, Mathematics
Abstract: The fractional flow reserve (FFR) provides an efficient quantitative assessment of the severity of a coronary lesion. Our aim is to address the problem of computing non-invasive virtual fractional flow reserve (VFFR). In this paper, we present a preliminary study of the main features of flow over a stenosed coronary arterial portion, in order to enumerate the different factors affecting the VFFR. We adopt a non-Newtonian flow model and we assume that the two-dimensional (2D) domain is rigid in a first place. In a second place, we consider a simplified weakly coupled FSI model in order to take into account the infinitesimal displacements of the upper wall. A 2D finite element solver was implemented using Freefem++. We computed the VFFR profiles with respect to different lesion parameters and compared the results given by the rigid wall model to those obtained for the elastic wall one.
Published: 2018

46. A left bundle branch block activation sequence and ventricular pacing influence voltage amplitudes: an in vivo and in silico study

Author: Francesco Maffessanti, François Regoli, Maria Luce Caputo, Giulio Conte, Jordi Heijman, Uyên Châu Nguyên, Angelo Auricchio, Frits W. Prinzen, Mark Potse, Kevin Vernooy, Masih Mafi-Rad, Rolf Krause, T. Moccetti, Cardiologie, MUMC+: MA Med Staf Spec Cardiologie (9), RS: CARIM - R2.08 - Electro mechanics, MUMC+: MA Med Staf Artsass Cardiologie (9), RS: CARIM - R2 - Cardiac function and failure, RS: CARIM - R2.01 - Clinical atrial fibrillation, RS: CARIM - R2.04 - Arrhythmogenisis and cardiogenetics, Fysiologie, Department of Physiology [Maastricht], Maastricht University [Maastricht], Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Radboud University Medical Center [Nijmegen], Cardiovascular Research Institute Maastricht (CARIM), Cardiocentro Ticino [Lugano], Universität Zürich [Zürich] = University of Zurich (UZH), Institute of Computational Science (ICS), Università della Svizzera italiana = University of Italian Switzerland (USI), Center for Computational Medicine in Cardiology [Lugano], This work was granted access to HPC resources of CEA-TGCC under GENCI allocation x2016037379 and was supported by grants from the Swiss National Science Foundation under project 32003B_165802, from the Swiss Heart Foundation, and by a restricted grant of Biologic Delivery Systems, Division of Biosense Webster a Johnson & Johnson Company. U.C.N. received a Kootstra Talent Fellowship research grant from Maastricht University Medical Center þ and was additionally funded by a research grant from the Dutch Heart Foundation [grant #2015T61]., ANR-10-IAHU-0004,LIRYC,L'Institut de Rythmologie et modélisation Cardiaque(2010), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, University of Zurich, and Nguyên, Uyên Châu
Subjects: Male, Time Factors, medicine.medical_treatment, Vascular damage Radboud Institute for Health Sciences [Radboudumc 16], Action Potentials, 02 engineering and technology, PROPAGATION, 030204 cardiovascular system & hematology, Ventricular Function, Left, Voltage amplitude, Electrocardiography, 2737 Physiology (medical), 0302 clinical medicine, Heart Rate, Interquartile range, Aged, 80 and over, medicine.diagnostic_test, Left bundle branch block, Cardiac Pacing, Artificial, Models, Cardiovascular, Middle Aged, Magnetic Resonance Imaging, Treatment Outcome, Cardiology, HEART-FAILURE, Female, CARDIAC RESYNCHRONIZATION THERAPY, Electrophysiologic Techniques, Cardiac, Cardiology and Cardiovascular Medicine, Adult, Intra-cardiac electrogram, Bundle of His, medicine.medical_specialty, Bundle-Branch Block, 0206 medical engineering, Cardiac resynchronization therapy, 610 Medicine & health, Heart failure, 11171 Cardiocentro Ticino, 2705 Cardiology and Cardiovascular Medicine, 03 medical and health sciences, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Internal medicine, Heart rate, medicine, Humans, Computer Simulation, Endocardium, Aged, business.industry, Magnetic resonance imaging, Computer models, medicine.disease, 020601 biomedical engineering, MODEL, CONDUCTION, Ventricular Function, Right, Anisotropy, Activation sequence, business
Abstract: Item does not contain fulltext Aims: The aim of this study was to investigate the influence of the activation sequence on voltage amplitudes by evaluating regional voltage differences during a left bundle branch block (LBBB) activation sequence vs. a normal synchronous activation sequence and by evaluating pacing-induced voltage differences. Methods and results: Twenty-one patients and three computer models without scar were studied. Regional voltage amplitudes were evaluated in nine LBBB patients who underwent endocardial electro-anatomic mapping (EAM). Pacing-induced voltage differences were evaluated in 12 patients who underwent epicardial EAM during intrinsic rhythm and right ventricular (RV) pacing. Three computer models customized for LBBB patients were created. Changes in voltage amplitudes after an LBBB (intrinsic), a normal synchronous, an RV pacing, and a left ventricular pacing activation sequence were assessed in the computer models. Unipolar voltage amplitudes in patients were approximately 4.5 mV (4.4-4.7 mV, approximately 33%) lower in the septum when compared with other segments. A normal synchronous activation sequence in the computer models normalized voltage amplitudes in the septum. Pacing-induced differences were larger in electrograms with higher voltage amplitudes during intrinsic rhythm and furthermore larger and more variable at the epicardium [mean absolute difference: 3.6-6.2 mV, 40-53% of intrinsic value; interquartile range (IQR) differences: 53-63% of intrinsic value] compared to the endocardium (mean absolute difference: 3.3-3.8 mV, 28-30% of intrinsic value; IQR differences: 37-40% of intrinsic value). Conclusion: In patients and computer models without scar, lower septal unipolar voltage amplitudes are exclusively associated with an LBBB activation sequence. Pacing substantially affects voltage amplitudes, particularly at the epicardium.
Published: 2018

47. Quantifying the determinants of decremental response in critical ventricular tachycardia substrate

Author: Shouvik Haldar, Karl Magtibay, Mohammadali Beheshti, Sachin Nayyar, Andreu Porta-Sánchez, Stéphane Massé, Edward J. Vigmond, Abhishek Bhaskaran, Kumaraswamy Nanthakumar, University Health Network, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)
Subjects: medicine.medical_specialty, DEEP, Heart Ventricles, 0206 medical engineering, Diastole, Health Informatics, Stimulation, Healthy tissue, 02 engineering and technology, 030204 cardiovascular system & hematology, Ventricular tachycardia, Electrocardiography, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Heart Conduction System, Internal medicine, medicine, Humans, Ventricular tissue, business.industry, Cell model, Arrhythmias, Cardiac, Heart, Cardiac modeling, medicine.disease, Vt ablation, 020601 biomedical engineering, Computer Science Applications, Mapping, Catheter Ablation, Tachycardia, Ventricular, Cardiology, [SDV.IB]Life Sciences [q-bio]/Bioengineering, Electrophysiologic Techniques, Cardiac, business
Abstract: Background Decremental response evoked with extrastimulation (DEEP) is a useful tool for determining diastolic return path of ventricular tachycardia (VT). Though a targeted VT ablation is feasible with this approach, determinants of DEEP response have not been studied Objectives To elucidate the effects of clinically relevant factors, specifically, the proximity of the stimulation site to the arrhythmogenic scar, stimulation wave direction, number of channels open in the scar, size of the scar and number of extra stimuli on decrement and entropy of DEEP potentials. Methods In a 3-dimensional bi-domain simulation of human ventricular tissue (TNNP cell model), an irregular subendocardial myopathic region was generated. An irregular channel of healthy tissue with five potential entry branches was shaped into the myopathic region. A bipolar electrogram was derived from two electrodes positioned in the centre of the myopathic region. Evoked delays between far-field and local Electrogram (EGM) following an extrastimulus (S1-S2, 500-350 ms) were measured as the stimulation site, channel branches, and inexcitable tissue size were altered. Results Stimulation adjacent to the inexcitable tissue from the side opposite to the point-of-entry produces longest DEEP delay. The DEEP delay shortens when the stimulation point is farther away from the scar, and it decreases maximally when stimulation is done from a site beside a conduction barrier. Entropy increases with S2 when stimulation site is from farther away. An unprotected channel structure with multiple side-branch openings had shorter DEEP delay compared to a protected channel structure with a paucity of additional side-branch openings and a point-of-entry on the side opposite to the pacing source. Addition of a second shorter extrastimulus did not universally lead to higher DEEP delay Conclusions Location and direction of the wavefront in relation to scar entry and size of scar determine the degree of evoked response while the number of extrastimuli has a small additional decremental effect
Published: 2018

48. Transmural APD gradient synchronizes repolarization in the human left ventricular wall

Author: Bastiaan J. Boukens, Fu Siong Ng, Igor R. Efimov, Christopher R Gloschat, Edward J. Vigmond, Matthew S. Sulkin, The George Washington University (GW), Washington University in Saint Louis (WUSTL), Imperial College London, Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)
Subjects: Adult, Male, medicine.medical_specialty, Optical mapping, Physiology, Repolarization, Action Potentials, 030204 cardiovascular system & hematology, Ventricular Function, Left, Electrocardiography, 03 medical and health sciences, 0302 clinical medicine, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Physiology (medical), Internal medicine, medicine, Humans, cardiovascular diseases, Child, Endocardium, Aged, 030304 developmental biology, 0303 health sciences, Chemistry, T wave, Ventricular wall, Original Articles, Middle Aged, musculoskeletal system, medicine.disease, Homogeneous, Ventricular fibrillation, cardiovascular system, Cardiology, Action potential duration, Female, Cardiology and Cardiovascular Medicine, [SDV.MHEP]Life Sciences [q-bio]/Human health and pathology, Left ventricular wall, Human
Abstract: Aims The duration and morphology of the T wave predict risk for ventricular fibrillation. A transmural gradient in action potential duration (APD) in the ventricular wall has been suggested to underlie the T wave in humans. We hypothesize that the transmural gradient in APD compensates for the normal endocardium-to-epicardium activation sequence and synchronizes repolarization in the human ventricular wall. Methods and results We made left ventricular wedge preparations from 10 human donor hearts and measured transmural activation and repolarization patterns by optical mapping, while simultaneously recording a pseudo-ECG. We also studied the relation between local timings of repolarization with the T wave in silico . During endocardial pacing (1 Hz), APD was longer at the subendocardium than at the subepicardium (360 ± 17 vs. 317 ± 20 ms, P < 0.05). The transmural activation time was 32 ± 4 ms and resulted in final repolarization of the subepicardium at 349 ± 18 ms. The overall transmural dispersion in repolarization time was smaller than that of APD. During epicardial pacing, the dispersion in repolarization time increased, whereas that of APD remained similar. The morphology of the T wave did not differ between endocardial and epicardial stimulation. Simulations explained the constant T wave morphology without transmural APD gradients. Conclusion The intrinsic transmural difference in APD compensates for the normal cardiac activation sequence, resulting in more homogeneous repolarization of the left ventricular wall. Our data suggest that the transmural repolarization differences do not fully explain the genesis of the T wave.
Published: 2015

49. Non Invasive Assessment of Spatiotemporal Organization of Ventricular Fibrillation through Principal Component Analysis

Author: Rémi Dubois, Marianna Meo, Mark Potse, Michel Haïssaguerre, Stéphane Puyo, Laura Bear, Mélèze Hocini, IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Centre de recherche Cardio-Thoracique de Bordeaux [Bordeaux] (CRCTB), Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Haut-Lévêque [CHU Bordeaux], CHU Bordeaux [Bordeaux], Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), and Potse, Mark
Subjects: medicine.medical_specialty, Pig heart, 0206 medical engineering, Non invasive, 02 engineering and technology, 030204 cardiovascular system & hematology, medicine.disease, 020601 biomedical engineering, Sudden cardiac death, [SDV.MHEP.CSC] Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, 03 medical and health sciences, 0302 clinical medicine, medicine.anatomical_structure, Reconstruction error, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Ventricle, Internal medicine, Principal component analysis, Ventricular fibrillation, medicine, Cardiology, Sinus rhythm, Mathematics
Abstract: International audience; Introduction Ventricular fibrillation (VF) is the main cause of sudden cardiac death. Despite its clinical significance, there is still a lack of quantitative tools to evaluate the degree of myocardial electrical organization during VF. This study puts forward novels markers of VF complexity and stability on body surface potential maps (BSPMs), uantifying the ability of signal features determined through principal component analysis (PCA) to be retrieved along the recording.Methods Biventricular potential mapping was performed through a 252-electrode vest in 27 VF patients (25 male, 49 ± 22 years). BSPMs were divided in 0:5-s segments, each projected on a 3D subspace determined through PCA in the preceding segment. At each time instant, the multilead error E between the input signal and its PCA approximation was expressed in terms of normalized amplitude norm |E| and angle cos(E). Additionally, the nondipolar component index (NDI) was determined as the fraction of energy retained by the first 3 PCA eigenvalues in sliding windows of the same duration. In 24 VF recordings (duration 19.8±6.5 s), average values of the aforementioned indices were computed in 4-second windows at the beginning and at the end of the outputparameter series. Temporal changes in VF complexity were verified through an unpaired Student’s t-test. The same analysis was performed in 5 control recordings in sinus rhythm (SR). Results A significant increase in spatiotemporal complexity was observed during VF, quantified by higher NDI and |E| and lower cos(E) values at the end of the episode (p < 0:0001). By contrast, no significant changes between the beginning and the end of the recording were observed during SR (p > 0:05).Conclusions This study demonstrates the ability of PCA to capture and quantify changes in signal complexity during VF in a noninvasive framework.
Published: 2017

50. Computational assessment of the functional role of sinoatrial node exit pathways in the human heart

Author: Sanjay Kharche, Halina Dobrzynski, Igor R. Efimov, Edward J. Vigmond, University of Manchester [Manchester], Modélisation et calculs pour l'électrophysiologie cardiaque (CARMEN), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Washington State University (WSU), Institut de Mathématiques de Bordeaux (IMB), Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Segalen - Bordeaux 2-Université Sciences et Technologies - Bordeaux 1 (UB)-Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IHU-LIRYC, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]-CHU Bordeaux [Bordeaux]
Subjects: 0301 basic medicine, Tachycardia, Computer science, Physiology, Action Potentials, 030204 cardiovascular system & hematology, Biochemistry, Diffusion, 0302 clinical medicine, Heart Rate, Atrial Fibrillation, Medicine and Health Sciences, Biochemical Simulations, Sinoatrial Node, Multidisciplinary, Simulation and Modeling, Physics, Gap junction, Models, Cardiovascular, Gap Junctions, Atrial fibrillation, Heart, Cardiovascular physiology, Electrophysiology, medicine.anatomical_structure, Physical Sciences, Cardiology, cardiovascular system, Right atrium, Medicine, medicine.symptom, Electrical conduction system of the heart, Pacemakers, Research Article, Biotechnology, medicine.medical_specialty, Science, Neurophysiology, Research and Analysis Methods, Membrane Potential, 03 medical and health sciences, Imaging, Three-Dimensional, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Heart Conduction System, Internal medicine, medicine, Humans, Computer Simulation, Heart Atria, cardiovascular diseases, Atrial tachycardia, Sinoatrial node, Biology and Life Sciences, Computational Biology, Models, Theoretical, medicine.disease, Fibrosis, Coupling (electronics), 030104 developmental biology, Atrial fibrosis, Waves, Anisotropy, Medical Devices and Equipment, Wave Propagation, Neuroscience, Developmental Biology
Abstract: Aim: The human right atrium and sinoatrial node (SAN) anatomy is complex. Opticalmapping experiments suggest that the SAN is functionally insulated from atrial tissueexcept at discrete SAN-atrial electrical junctions called SAN exit pathways, SEPs.Additionally, histological imaging suggests the presence of a secondary pacemakerclose to the SAN. We hypothesise that a) an insulating border-SEP anatomicalconfiguration is related to SAN arrhythmia; and b) a secondary pacemaker, theparanodal area, is an alternate pacemaker but accentuates tachycardia. A 3D electroanatomicalcomputational model was used to test these hypotheses.Methods: A detailed 3D human SAN electro-anatomical mathematical model wasdeveloped based on our previous anatomical reconstruction. Electrical activity wassimulated using tissue specific variants of the Fenton-Karma action potential equations.Simulation experiments were designed to deploy this complex electro-anatomicalsystem to assess the roles of border-SEPs and paranodal area by mimickingexperimentally observed SAN arrhythmia. Robust and accurate numerical algorithmswere implemented for solving the mono domain reaction-diffusion equation implicitly,calculating 3D filament traces, and computing dominant frequency among otherquantitative measurements.Results: A centre to periphery gradient of increasing diffusion was sufficient to permitinitiation of pacemaking at the centre of the 3D SAN. Re-entry within the SAN, microre-entry, was possible by imposing significant SAN fibrosis in the presence of theinsulating border. SEPs promoted the micro re-entry to generate more complex SANatrialtachycardia. Simulation of macro re-entry, i.e. re-entry around the SAN, waspossible by inclusion of atrial fibrosis in the presence of the insulating border. Theborder shielded the SAN from atrial tachycardia. However, SAN micro-structureintercellular gap junctional coupling and the paranodal area contributed to prolongedatrial fibrillation. Finally, the micro-structure was found to be sufficient to explain shiftsof leading pacemaker site location.Conclusions: The simulations establish a relationship between anatomy and SANelectrical function. Microstructure, in the form of intercellular gap junction coupling, wasfound to regulate SAN function and arrhythmia.
Published: 2017

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