Effect of scar distribution on transmural and planar repolarization gradients and dispersion in non-ischemic cardiomyopathies with ventricular arrhythmias

Abstract

Ventricular tachycardias (VT) in non-ischemic cardiomyopathies (NICM) arise from a complex interplay between structural myocardial changes and dynamic electrophysiological properties. Yet, conventional substrate mapping strategies and imaging remain focused on identifying fixed structural and/or conduction abnormalities, often neglecting other functional elements such as repolarization changes. Altered repolarization contributes to increased susceptibility to re-entrant VTs in ischemic heart disease yet its proarrhythmogenic role in NICM is poorly characterized. Moreover, the impact of transmural scar distribution on 3-dimensional repolarization patterns remains underexplored due to the restriction of conventional mapping approaches to endo- and epicardial surfaces. This study aimed to assess transmural and planar repolarization heterogeneity in NICM, stratified by myocardial scar pattern, by integrating electro-anatomical mapping (EAM) with delayed enhancement MRI (DE-MRI) in patients undergoing clinical VT ablation.