Interlead heterogeneity of R- and T-Wave morphology in standard 12-lead ECGs predicts sustained ventricular tachycardia/fibrillation and arrhythmic death in patients with cardiomyopathy

Introduction Nonuniformities in depolarization and repolarization morphology are critical factors in ventricular arrhythmogenesis. Methods and results We assessed interlead R-wave and T-wave heterogeneity (RWH, TWH) in standard 12-lead electrocardiograms using second central moment analysis. This technique quantifies variance about the mean morphology of beats in adjoining precordial leads, V4, V5, and V6. The study was conducted in 120 consecutive patients without an apparent reversible trigger for VT, recent myocardial infarction, or active ischemia, who presented for electrophysiologic study, implantable cardioverter defibrillator (ICD) placement, or generator change at our institution from 2008 to 2011. Primary outcome was sustained VT/VF or appropriate ICD therapies. Secondary outcome was arrhythmic death or resuscitated cardiac arrest. Cutpoints for elevated RWH (>160 μV) and TWH (>80 μV) identified 69% of primary outcome cases and 85% of secondary outcome cases. Cardiomyopathy patients who met the primary outcome (n = 42) had significantly higher TWH than those who did not (n = 28) (TWH: 95±11 vs. 44±9 μV, p<0.002). Likewise, cardiomyopathy patients who met secondary outcome (N = 13) had VT/VF during follow-up and also had significantly higher TWH than survivors (N = 57) (TWH: 105±24 vs. 67±8μV, p<0.002). Kaplan-Meier analysis revealed significant differences in arrhythmia-free survival (p = 0.012) and total survival (p = 0.011) among cardiomyopathy patients with (n = 37) compared to without (n = 33) elevated RWH and/or TWH independent of age, sex, and left ventricular ejection fraction (LVEF). Conclusion Interlead RWH and TWH in 12-lead ECGs predict sustained ventricular arrhythmia, appropriate ICD therapies, and arrhythmic death or cardiac arrest in cardiomyopathy patients independent of LVEF and other standard variables. This article is protected by copyright. All rights reserved