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Objective&xD;This study examines the value of ventricular repolarization using QT dynamicity for two different types of atrial fibrillation (AF) prediction. &xD;Approach&xD;We studied the importance of QT-dynamicity 1) in the detection and 2) the onset prediction (i.e. forecasting) of paroxysmal AF episodes using gradient-boosted decision trees (GBDT), an interpretable machine learning technique. We labeled 176 paroxysmal AF onsets from 88 patients in our unselected Holter recordings database containing paroxysmal AF episodes. Raw ECG signals were delineated using a wavelet-based signal processing technique. A total of 44 ECG features related to interval and wave durations and amplitude were selected. and the GBDT model was trained with a Bayesian hyperparameters selection for various windows. &xD;Main results&xD;The mean age of the patients was 75.9±11.9 (range 50-99), the number of episodes per patient was 2.3±2.2 (range 1-11), and CHA2DS2-VASc score was 2.9±1.7 (range 1-9). For the detection of AF, we obtained an area under the receiver operating curve (AUROC) of 0.99 (CI 95% 0.98 - 0.99) using a 30s window. Features related to RR intervals were the most influential, followed by those on QT intervals. For the AF onset forecast, we obtained an AUROC of 0.739 (0.712-0.766) using a 120s window. R wave amplitude and QT dynamicity as assessed by Spearman’s correlation of the QT-RR slope were the best predictors. &xD;Significance&xD;The QT dynamicity can be used to accurately predict the onset of AF episodes. Ventricular repolarization, as assessed by QT dynamicity, adds information that allows for better short time prediction of AF onset, compared to relying only on RR intervals and HRV. Communication between the ventricles and atria is mediated by the autonomic nervous system. The variations in intraventricular conduction and ventricular repolarization changes resulting from the influence of the ANS play a role in the initiation of AF.&xD, SCOPUS: ar.j, info:eu-repo/semantics/published

Atrial fibrillation (AF) is one of the most common heart rhythm disorders. Patients affected by this condition have a fivefold increased risk of stroke. During AF, irregular atrial contractions disrupt the normal cardiac cycle, resulting in irregular heartbeats. This thesis proposes a machine learning (ML) approach to predict the onset of paroxysmal AF episodes using electrocardiograms (ECG). A new database of long-term ECG recordings from patients with AF, annotated by a cardiologist, was created. ML models were trained on these data to predict the onset of AF. We showed that model performance improved as the prediction got closer to the onset of AF. Models using heart rate variability and RR intervals performed better than those using raw ECG signals. We then selected ECG recordings from healthy people and added them to the database. These additional recordings made it possible to compare the sinus rhythm of healthy people and people with AF. ML models were able to identify the signatures of AF within sinus rhythm, suggesting the possibility of improving AF screening and treatment strategies using ML techniques., Doctorat en Sciences de l'ingénieur et technologie, info:eu-repo/semantics/nonPublished

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The role of the autonomic nervous system in the onset of supraventricular and ventricular arrhythmias is well established. It can be analysed by the spontaneous behaviour of the heart rate with ambulatory ECG recordings, through heart rate variability measurements. Input of heart rate variability parameters into artificial intelligence models to make predictions regarding the detection or forecast of rhythm disorders is becoming routine and neuromodulation techniques are now increasingly used for their treatment. All this warrants a reappraisal of the use of heart rate variability for autonomic nervous system assessment.Measurements performed over long periods such as 24H-variance, total power, deceleration capacity, and turbulence are suitable for estimating the individual basal autonomic status. Spectral measurements performed over short periods provide information on the dynamics of systems that disrupt this basal balance and may be part of the triggers of arrhythmias, as well as premature atrial or ventricular beats. All heart rate variability measurements essentially reflect the modulations of the parasympathetic nervous system which are superimposed on the impulses of the adrenergic system. Although heart rate variability parameters have been shown to be useful for risk stratification in patients with myocardial infarction and patients with heart failure, they are not part of the criteria for prophylactic implantation of an intracardiac defibrillator, because of their high variability and the improved treatment of myocardial infarction. Graphical methods such as Poincaré plots allow quick screening of atrial fibrillation and are set to play an important role in the e-cardiology networks. Although mathematical and computational techniques allow manipulation of the ECG signal to extract information and permit their use in predictive models for individual cardiac risk stratification, their explicability remains difficult and making inferences about the activity o, SCOPUS: re.j, info:eu-repo/semantics/published

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(1) Background: Stent underexpansion is the main cause of stent thrombosis and restenosis. Coronary angiography has limitations in the assessment of stent expansion. Enhanced stent imaging (ESI) methods allow a detailed visualization of stent deployment. We qualitatively compare image results from two ESI system vendors (StentBoost™ (SB) and CAAS StentEnhancer™ (SE)) and report quantitative results of deployed stents diameters by quantitative coronary angiography (QCA) and by SE. (2) Methods: The ESI systems from SB and SE were compared and graded by two blinded observers for different characteristics: 1 visualization of the proximal and distal edges of the stents; 2 visualization of the stent struts; 3 presence of underexpansion and 4 calcifications. Stent diameters were quantitatively measured using dedicated QCA and SE software and compared to chart diameters according to the pressure of implantation. (3) Results: A total of 249 ESI sequences were qualitatively compared. Inter-observer variability was noted for strut visibility and total scores. Inter-observer agreement was found for the assessment of proximal stent edge and stent underexpansion. The predicted chart diameters were 0.31 ± 0.30 mm larger than SE diameters (p < 0.05). Stent diameters by SE after post-dilatation were 0.47 ± 0.31 mm smaller than the post-dilation balloon diameter (p < 0.05). SE-derived diameters significantly differed from QCA; by Bland–Altman analysis the bias was −0.37 ± 0.42 mm (p < 0.001). (4) Conclusions: SE provides an enhanced visualization and allows precise quantitative assessment of stent expansion without the limitations of QCA when overlapping coronary side branches are present., SCOPUS: ar.j, info:eu-repo/semantics/published

Cardiovascular diseases are the leading causes of death worldwide, closely followed by cancer. To investigate the impact of breast cancer cell lines (SKBR3, MCF-7, and MDA-MB-231) on endothelial cell adhesion, a blended medium containing 30% breast-cancer-conditioned medium was prepared. This medium was then exposed to human umbilical vein endothelial cells (HUVECs) and monocytes (THP-1) for 48 h. Homemade oxidized low-density lipoproteins (oxLDL) were optionally added to the blended medium. Immunofluorescence was performed to assess the expression of E-selectin, connexin-43, and ICAM-1 on HUVECs, as well as LOX-1, CD36, and CD162 on THP-1. Additionally, unoxidized LDL was exposed to the three breast cancer cell lines for 48 h, and the formation of oxLDL was quantified. Our results revealed an upregulation of all six adhesion markers involved in the initiation of atherosclerosis when HUVECs and THP-1 were exposed to the breast-cancer-conditioned medium. Furthermore, this expression was further increased by exposure to oxLDL. We also observed a significant elevation in oxLDL levels when LDL was exposed to breast cancer cells. In conclusion, our findings successfully demonstrate an increased LDL oxidation in the presence of breast cancer cells, accompanied by an augmented expression of receptors involved in atherosclerosis initiation. These findings shed new light on the clinically observed interplay between atherosclerosis and cancer., SCOPUS: ar.j, info:eu-repo/semantics/published

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Cardiovascular disease (CVD) is one of the leading causes of death in Belgium. Current strategies for the prevention and management of CVD focus on reducing low-density lipoprotein cholesterol (LDL-C) levels. This analysis assessed whether LDL-C goals, recommended by the European Society of Cardiology (ESC)/European Atherosclerosis Society (EAS) guidelines, were being achieved in a Belgian study population. The cross-sectional, observational, DA VINCI study enrolled patients prescribed lipid-lowering therapy (LLT) between 21 June 2017 and 20 November 2018. Data for patients from Belgium were extracted for this country-specific analysis. Primary endpoint was the proportion of patients who achieved 2016 ESC/EAS risk-based LDL-C goals; attainment of 2019 risk-based LDL-C goals was evaluated . Of 497 enrolled patients, 41% were female and mean age was 68 years. Among subjects with an LDL-C measurement on stabilised LLT, moderate-intensity statin monotherapy was the most prescribed LLT regimen (59%). Overall, 63% of patients achieved their risk-based LDL-C goals according to the 2016 ESC/EAS guidelines. Among patients with established ASCVD, risk-based LDL-C goal attainment was higher in patients with peripheral arterial disease (53%) than patients with coronary (37%) and cerebrovascular disease (42%). According to the updated 2019 ESC/EAS guidelines, less than half (41%) of patients achieved their risk-based LDL-C goal. The proportion of primary and secondary prevention patients who achieved 2019 risk-based LDL-C goals was 59% and 18%, respectively. These findings reveal a large gap between the LDL-C goals advocated by the ESC/EAS and the levels achieved in routine clinical practice in Belgium.

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Microgravity is a hostile environment for the cardiovascular system. It triggers a cascade of adaptations that lead to problems on return to gravity. With the relatively low number of astronauts and the current duration of their spaceflights, some unknowns remain regarding the exact risks of future interplanetary missions. In addition, the current countermeasures are suboptimal and there is a high inter-subject variability that is still poorly understood. It will thus be necessary to closely monitor the cardiovascular health of the future interplanetary crews with the constraints of such expeditions, i.e. limited mass and volume, absence of resupply, delay in the communications, etc. Accordingly, the main objective of this research is to evaluate the possibility to use wearable devices based on the micro-vibrations generated by the cardiovascular activity – measured on the chest (SCG) or at the center of mass (BCG) – to bring information about the cardiovascular status of astronauts.Firstly, the results from a study simulating microgravity by 60-day exposure to head-down tilt bed rest are reported. In particular, the fine adaptations of the cardiovascular system and the impact of a countermeasure based on artificial gravity are studied using 4D flow cardiac MRI. No significant effect of this countermeasure is found in the tested setup. During the head-down tilt phase, the cardiac output decreased because of a smaller blood flow towards the lower body. In parallel, the aortic pulse wave velocity increased. However, all these changes were reversible and seemed to indicate only functional adaptations. It is noteworthy that BCG and SCG have the potential to follow the trends in cardiac output and pulse wave velocity, which will soon be tested using these MRI data as a reference.Secondly, the results from another 60-day head-down tilt bed rest study are reported. The aim is to evaluate the possibility for SCG and BCG to report the longitudinal cardiovascular changes occu, La micropesanteur représente un environnement hostile pour le système cardiovasculaire. Elle entraîne une cascade d’adaptations menant à des problèmes lors du retour à la pesanteur. Étant donnés le nombre relativement faible d’astronautes et la durée actuelle de leurs vols, certaines inconnues demeurent en ce qui concerne les risques exacts des futures missions interplanétaires. Par ailleurs, les contremesures actuellement employées sont sous-optimales et l’on observe une forte variabilité inter-sujet qui est encore mal comprise. Il sera donc nécessaire de suivre de près la santé cardiovasculaire des futures équipages interplanétaires, avec toutes les contraintes de telles expéditions, c’est-à-dire une masse et un volume limités, une absence de ravitaillement, un délai dans les communications, etc. Dans ce contexte, l’objectif principal de cette recherche est d’évaluer la possibilité d’utiliser un système portable basé sur les micro-vibrations générées par l’activité cardiovasculaire – mesurées au niveau de la poitrine (SCG) ou bien du centre de masse (BCG) – afin d’apporter des informations sur l’état cardiovasculaire des astronautes.Premièrement, les résultats d’une étude de simulation de la micropesanteur de 60 jours par alitement tête-en-bas sont rapportés. En particulier, les adaptations fines du système cardiovasculaire, ainsi que l’impact d’une contremesure basée sur la gravité artificielle, sont étudiés en utilisant des protocoles d’IRM cardiaque avec flux 4D. Aucun effet significatif de cette contremesure n’a été identifié dans la configuration testée. Au cours de la phase tête-en-bas, le débit cardiaque a diminué en raison d’une baisse du flux vers le bas du corps. En parallèle la vitesse d’onde de pouls a augmenté. Néanmoins, ces changements se sont avérés réversibles et semblaient n’indiquer que des adaptations fonctionnelles. Il est intéressant de noter que le BCG et le SCG ont le potentiel de suivre ce type de tendance en termes de débit cardiaque et d, Doctorat en Sciences de l'ingénieur et technologie, info:eu-repo/semantics/nonPublished

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Cardiovascular diseases (CVD) and cancers are the two main causes of death worldwide. The initiation and progression of atherosclerosis is, in large part, caused by oxidized low-density lipoproteins (oxLDL); interestingly, oxLDL may also play a role in cancer cell metabolism and migration. As oxLDL are generally obtained by tedious ultracentrifugation procedures, “home-made” oxLDL were obtained by (i) applying a purification kit to isolate LDL and VLDL from human plasma; (ii) isolating LDL from VLDL by gel permeation chromatography (GPC); and (iii) oxidating LDL through CuSO4 incubation. On three HPV-positive head and neck cancer cells (HNCC) (93VU-147T, UM-SCC47, and UPCI-SCC154), cell migration was assessed using Boyden chambers, the Wnt/ß-catenin pathway was analyzed by Western Blotting, and the expression of two oxLDL receptors, LOX-1 and CD36, in response to oxLDL exposure, was analysed by immunofluorescence. Our data indicate: (a) a non-significant difference between reference and “home-made” oxLDL; (b) a decreased migration, parallel to an inhibition of the ß-catenin pathway; and (c) an increase of CD36 and LOX-1 expression in all HNCC. In conclusion, we successfully produced oxLDL. Our results demonstrate a decrease in HNCC migration after oxLDL exposure, and an increased expression of LOX-1 and CD36 associated with lipid uptake., SCOPUS: ar.j, info:eu-repo/semantics/published