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Background Juvenile onset of extensive atrial electromechanical failure, including atrial standstill, is a rare disease entity that may precede ventricular cardiomyopathy. Genetic variants associated with early-onset atrioventricular (AV) cardiomyopathy are increasingly recognized. Case summary A 16-year-old patient presented with atrial brady- and tachyarrhythmias and concomitant impaired atrial electromechanical function (atrial standstill). The atrial phenotype preceded the development of a predominantly right-sided AV dilated cardiomyopathy with pronounced myocardial fibrosis. A His-bundle pacemaker was installed for high-degree AV conduction block and sinus arrest. Using familial-based whole-exome sequencing, a missense mutation and a copy number variant deletion (compound heterozygosity) of the TAF1A gene (involved in ribosomal RNA synthesis) were identified. Discussion Juvenile onset of severe atrial electromechanical failure with atrial arrhythmias should prompt deep pheno- and genotyping and calls for vigilance for downstream cardiomyopathic deterioration. [ABSTRACT FROM AUTHOR]

Aims To evaluate the performance of various semi-automated techniques for quantification of myocardial infarct size on both conventional bright-blood and novel dark-blood late gadolinium enhancement (LGE) images using histopathology as reference standard. Methods and results In 13 Yorkshire pigs, reperfused myocardial infarction was experimentally induced. At 7 weeks post-infarction, both bright-blood and dark-blood LGE imaging were performed on a 1.5 T magnetic resonance scanner. Following magnetic resonance imaging (MRI), the animals were sacrificed, and histopathology was obtained. The percentage of infarcted myocardium was assessed per slice using various semi-automated scar quantification techniques, including the signal threshold vs. reference mean (STRM, using 3 to 8 SDs as threshold) and full-width at half-maximum (FWHM) methods, as well as manual contouring, for both LGE methods. Infarct size obtained by histopathology was used as reference. In total, 24 paired LGE MRI slices and histopathology samples were available for analysis. For both bright-blood and dark-blood LGE, the STRM method with a threshold of 5 SDs led to the best agreement to histopathology without significant bias (−0.23%, 95% CI [−2.99, 2.52%], P = 0.862 and −0.20%, 95% CI [−2.12, 1.72%], P = 0.831, respectively). Manual contouring significantly underestimated infarct size on bright-blood LGE (−1.57%, 95% CI [−2.96, −0.18%], P = 0.029), while manual contouring on dark-blood LGE outperformed semi-automated quantification and demonstrated the most accurate quantification in this study (−0.03%, 95% CI [−0.22, 0.16%], P = 0.760). Conclusion The signal threshold vs. reference mean method with a threshold of 5 SDs demonstrated the most accurate semi-automated quantification of infarcted myocardium, without significant bias compared to histopathology, for both conventional bright-blood and novel dark-blood LGE. [ABSTRACT FROM AUTHOR]

Background: Conventional bright‐blood late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (MRI) often suffers from poor scar‐to‐blood contrast due to the bright blood pool adjacent to the enhanced scar tissue. Recently, a dark‐blood LGE method was developed which increases scar‐to‐blood contrast without using additional magnetization preparation. Purpose We aim to histopathologically validate this dark‐blood LGE method in a porcine animal model with induced myocardial infarction (MI). Study Type: Prospective. Animal Model: Thirteen female Yorkshire pigs. Field Strength/Sequence: 1.5 T, two‐dimensional phase‐sensitive inversion‐recovery radiofrequency‐spoiled turbo field‐echo. Assessment MI was experimentally induced by transient coronary artery occlusion. At 1‐week and 7‐week post‐infarction, in‐vivo cardiac MRI was performed including conventional bright‐blood and novel dark‐blood LGE. Following the second MRI examination, the animals were sacrificed, and histopathology was obtained. Matching LGE slices and histopathology samples were selected based on anatomical landmarks. Independent observers, while blinded to other data, manually delineated the endocardial, epicardial, and infarct borders on either LGE images or histopathology samples. The percentage of infarcted left‐ventricular myocardium was calculated for both LGE methods on a per‐slice basis, and compared with histopathology as reference standard. Contrast‐to‐noise ratios were calculated for both LGE methods at 1‐week and 7‐week post‐infarction. Statistical Tests: Pearson's correlation coefficient and paired‐sample t‐tests were used. Significance was set at P < 0.05. Results: A combined total of 24 matched LGE and histopathology slices were available for histopathological validation. Dark‐blood LGE demonstrated a high level of agreement compared to histopathology with no significant bias (−0.03%, P = 0.75). In contrast, bright‐blood LGE showed a significant bias of −1.57% (P = 0.03) with larger 95% limits of agreement than dark‐blood LGE. Image analysis demonstrated significantly higher scar‐to‐blood contrast for dark‐blood LGE compared to bright‐blood LGE, at both 1‐week and 7‐weeks post‐infarction. Data Conclusion: Dark‐blood LGE without additional magnetization preparation provides superior visualization and quantification of ischemic scar compared to the current in vivo reference standard. Level of Evidence: 1 Technical Efficacy Stage: 2 [ABSTRACT FROM AUTHOR]

Aims: To evaluate the performance of various semi-automated techniques for quantification of myocardial infarct size on both conventional bright-blood and novel dark-blood late gadolinium enhancement (LGE) images using histopathology as reference standard., Methods and Results: In 13 Yorkshire pigs, reperfused myocardial infarction was experimentally induced. At 7 weeks post-infarction, both bright-blood and dark-blood LGE imaging were performed on a 1.5 T magnetic resonance scanner. Following magnetic resonance imaging (MRI), the animals were sacrificed, and histopathology was obtained. The percentage of infarcted myocardium was assessed per slice using various semi-automated scar quantification techniques, including the signal threshold vs. reference mean (STRM, using 3 to 8 SDs as threshold) and full-width at half-maximum (FWHM) methods, as well as manual contouring, for both LGE methods. Infarct size obtained by histopathology was used as reference. In total, 24 paired LGE MRI slices and histopathology samples were available for analysis. For both bright-blood and dark-blood LGE, the STRM method with a threshold of 5 SDs led to the best agreement to histopathology without significant bias (-0.23%, 95% CI [-2.99, 2.52%], P = 0.862 and -0.20%, 95% CI [-2.12, 1.72%], P = 0.831, respectively). Manual contouring significantly underestimated infarct size on bright-blood LGE (-1.57%, 95% CI [-2.96, -0.18%], P = 0.029), while manual contouring on dark-blood LGE outperformed semi-automated quantification and demonstrated the most accurate quantification in this study (-0.03%, 95% CI [-0.22, 0.16%], P = 0.760)., Conclusion: The signal threshold vs. reference mean method with a threshold of 5 SDs demonstrated the most accurate semi-automated quantification of infarcted myocardium, without significant bias compared to histopathology, for both conventional bright-blood and novel dark-blood LGE., Competing Interests: Conflicts of interest: G.V. is an employee of Pie Medical Imaging. The other authors declare that they have no competing interest., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Materials and Methods: Fifty consecutive patients with previous cardiac arrhythmias, scheduled for high-resolution 3D LGE MRI, were prospectively enrolled between October 2017 and February 2020. Free-breathing 3D dark-blood LGE MRI with high isotropic resolution (1.6 × 1.6 × 1.6 mm) was performed using a conventional fixed TI (n = 25) or a dynamic TI (n = 25). The average increase in blood nulling TI per minute was obtained from Look-Locker scans before and after the 3D acquisition in the first fixed TI group. This average increment in TI was used as input to calculate the dynamic increment of the initial blood nulling TI value as set in the second dynamic TI group. Regions of interest were drawn in the left ventricular blood pool to assess mean signal intensity as a measure for blood pool suppression. Overall image quality, observer confidence, and scar demarcation were scored on a 3-point scale., Results: Three-dimensional dark-blood LGE data sets were successfully acquired in 46/50 patients (92%). The calculated average TI increase of 2.3 ± 0.5 ms/min obtained in the first fixed TI group was incorporated in the second dynamic TI group and led to a significant decrease of 72% in the mean blood pool signal intensity compared with the fixed TI group (P < 0.001). Overall image quality (P = 0.02), observer confidence (P = 0.02), and scar demarcation (P = 0.01) significantly improved using a dynamic TI., Conclusions: A steadily increasing dynamic TI improves blood pool suppression for optimized dark-blood contrast and increases observer confidence in free-breathing 3D dark-blood LGE MRI with high isotropic resolution., Competing Interests: Conflicts of interest and sources of funding: R.J.H., S.G., and J.E.W. acknowledge financial support from Stichting de Weijerhorst. R.J.H. was supported by an HS-BAFTA fellowship from the Cardiovascular Research Institute Maastricht (CARIM). J.S. and D.M.H. are employees of Philips Healthcare. J.E.W. receives institutional grants from Agfa Healthcare, Bard Medical, Bayer Healthcare, General Electric, Optimed, Philips Healthcare, and Siemens Healthineers. The other authors have no conflicts of interest to declare., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Aims: An appropriate left ventricular (LV) lead position is a pre-requisite for response to cardiac resynchronization therapy (CRT) and is highly patient-specific. The purpose of this study was to develop a non-invasive pre-procedural CRT-roadmap to guide LV lead placement to a coronary vein in late-activated myocardium remote from scar., Methods and Results: Sixteen CRT candidates were prospectively included. Electrocardiographic imaging (ECGI), computed tomography angiography (CTA), and delayed enhancement cardiac magnetic resonance imaging (DE-CMR) were integrated into a 3D cardiac model (CRT-roadmap) using anatomic landmarks from CTA and DE-CMR. Electrocardiographic imaging was performed using 184 electrodes and a CT-based heart-torso geometry. Coronary venous anatomy was visualized using a designated CTA protocol. Focal scar was assessed from DE-CMR. Cardiac resynchronization therapy-roadmaps were constructed for all 16 patients [left bundle branch block: n = 6; intraventricular conduction disturbance: n = 8; narrow-QRS (ablate and pace strategy); n = 1; right bundle branch block: n = 1]. The number of coronary veins ranged between 3 and 4 per patient. The CRT-roadmaps showed no (n = 5), 1 (n = 6), or 2 (n = 5) veins per patient located outside scar in late-activated myocardium [≥50% QRS duration (QRSd)]. Final LV lead position was outside scar in late-activated myocardium in 11 out of 14 implanted patients, while a LV lead in scar was unavoidable in the remaining three patients., Conclusion: A non-invasive pre-implantation CRT-roadmap was feasible to develop in a case series by integration of coronary venous anatomy, myocardial-scar localization, and epicardial electrical activation patterns, anticipating on clinically relevant features., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.)