BACKGROUND Anti-tachycardia pacing (ATP), which may avoid unnecessary ICD shocks, does not always terminate ventricular arrhythmias (VAs). Mean entropy calculated using cardiac magnetic resonance texture analysis (CMR-TA) has been shown to predict appropriate ICD therapy. We examined whether scar heterogeneity, quantified by mean entropy, is associated with ATP failure and explore potential mechanisms using computer modelling. METHODS A sub-analysis of 114 patients undergoing CMR-TA where the primary endpoint was delivery of appropriate ICD therapy (ATP or shock therapy) was performed. Patients receiving appropriate ICD therapy (n = 33) were dichotomized into 'successful ATP' versus 'shock therapy' groups. In silico computer modelling was used to explore underlying mechanisms. RESULTS A total of 16/33 (48.5%) patients had successful ATP to terminate VA and 17/33 (51.5%) required shock therapy. Mean entropy was significantly higher in the shock versus successful ATP group (6.1±0.5 vs. 5.5±0.7, p = 0.037). Analysis of patients receiving ATP (n = 22) showed significantly higher mean entropy in the 6/22 patients that failed ATP (followed by rescue ICD shock) compared to 16/22 that had successful ATP (6.3±0.7 vs. 5.5±0.7, p = 0.048). Computer modelling suggested inability of the paced wavefront in ATP to successfully propagate from the electrode site through patchy fibrosis as a possible mechanism of failed ATP. CONCLUSIONS Our findings suggest lower scar heterogeneity (mean entropy) is associated with successful ATP whereas higher scar heterogeneity is associated with more aggressive VAs unresponsive to ATP requiring shock therapy which may be due to inability of the paced wavefront to propagate through scar and terminate the VA circuit. This article is protected by copyright. All rights reserved.
Background Risk stratification of ventricular arrhythmia remains complex in patients with ischemic and nonischemic cardiomyopathy. Objective The purpose of this study was to determine whether scar heterogeneity, quantified by mean entropy, predicts appropriate implantable cardioverter-defibrillator (ICD) therapy. We hypothesized that higher mean entropy calculated from cardiac magnetic resonance texture analysis (CMR-TA) will predict appropriate ICD therapy. Methods Consecutive patients underwen...
Abstract Objectives The aim of this study was to assess the utility of left ventricular (LV) entropy, a novel measure of myocardial heterogeneity, for predicting cardiovascular events in patients with dilated cardiomyopathy (DCM). Background Current risk stratification for ventricular arrhythmia in patients with DCM is imprecise. LV entropy is a measure of myocardial heterogeneity derived from cardiac magnetic resonance imaging that assesses the probability distribution of pixel signal intensiti...
#2Katja Zeppenfeld(LUMC: Leiden University Medical Center)H-Index: 57
Last. Qian Tao(LUMC: Leiden University Medical Center)H-Index: 22
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Abstract Objectives This study proposed entropy as a new late gadolinium enhanced cardiac magnetic resonance–derived parameter to evaluate tissue inhomogeneity, independent of signal intensity thresholds. This study hypothesized that entropy within the scar is associated with ventricular arrhythmias (VAs), whereas entropy of the entire left ventricular (LV) myocardium is associated with mortality. Background In patients after myocardial infarction, the heterogeneity of fibrosis determines the su...
Aim To determine whether heterogeneity of cardiac scar, as assessed by cardiovascular magnetic resonance (CMR) texture analysis, may provide insight into better risk stratification for patients with previous myocardial infarction (MI). Materials and methods Patients with previous MI (n=76) were followed for a median of 371.5 days after late gadolinium enhancement (LGE) CMR. The primary endpoint was a composite of ventricular tachycardia, ventricular fibrillation, or unexplained syncope. Areas of...
Introduction The role of implantable cardioverter defibrillators in non-ischemic cardiomyopathy is unclear and better risk-stratification is required. We sought to determine if T1 mapping predicts appropriate defibrillator therapy in patients with non-ischemic cardiomyopathy. We studied a mixed cohort of ischemic and non-ischemic patients to determine whether different CMR applications (T1 mapping, late gadolinium enhancement and Grayzone) were selectively predictive of therapies for the differe...
Last. Paul A. Scott(University of Cambridge)H-Index: 6
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Large-scale implantable cardioverter defibrillator (ICD) trials have unequivocally shown a reduction in mortality in appropriately selected patients with heart failure and depressed left ventricular function. However, there is a strong association between shocks and increased mortality in ICD recipients. It is unclear if shocks are merely a marker of a more severe cardiovascular disease or directly contribute to the increase in mortality. The aim of this review is to examine the relationship bet...
Myocardial fibrosis is an important risk factor for cardiac arrhythmias. Previous experimental and numerical studies have shown that the texture and spatial distribution of fibrosis may play an important role in arrhythmia onset. Here, we investigate how spatial heterogeneity of fibrosis affects arrhythmia onset using numerical methods. We generate various tissue textures that differ by the mean amount of fibrosis, the degree of heterogeneity and the characteristic size of heterogeneity. We stud...
Authors/Task Force Members: Silvia G. Priori* (Chairperson) (Italy), Carina Blomstrom-Lundqvist* (Co-chairperson) (Sweden), Andrea Mazzanti† (Italy), Nico Blom (The Netherlands), Martin Borggrefe (Germany), John Camm (UK), Perry Mark Elliott (UK), Donna Fitzsimons (UK), Robert Hatala (Slovakia), Gerhard Hindricks (Germany), Paulus Kirchhof (UK/Germany), Keld Kjeldsen (Denmark), Karl-Heinz Kuck (Germany), Antonio Hernandez-Madrid (Spain), Nikolaos Nikolaou (Greece), Tone M. Norekval (Norway), Chr...
#1Zhong Chen('KCL': King's College London)H-Index: 18
#2Manav Sohal('KCL': King's College London)H-Index: 18
Last. C. Aldo Rinaldi('KCL': King's College London)H-Index: 24
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Background Diffuse myocardial fibrosis may provide a substrate for the initiation and maintenance of ventricular arrhythmia. T1 mapping overcomes the limitations of the conventional delayed contrast-enhanced cardiac magnetic resonance (CE-CMR) imaging technique by allowing quantification of diffuse fibrosis. Objective The purpose of this study was to assess whether myocardial tissue characterization using T1 mapping would predict ventricular arrhythmia in ischemic and non–ischemic cardiomyopathi...
Cardiac arrhythmia is associated with high morbidity, and its underlying mechanisms are poorly understood. Computational modelling and simulation approaches have the potential to improve standard-of-care therapy for these disorders, offering deeper understanding of complex disease processes and sophisticated translational tools for planning clinical procedures. This review provides a clinician-friendly summary of recent advancements in computational cardiology. Organ-scale models automatically g...