Comparison of the arrhythmogenic substrate between men and women with nonischemic cardiomyopathy

BACKGROUND Outcomes of ventricular tachycardia (VT) ablation in structural heart disease have been reported to differ by sex. Whether this is due to differences in the underlying arrhythmogenic substrates among patients with nonischemic cardiomyopathy (NICM) remains unclear. OBJECTIVE The purpose of this study was to compare the characteristics of arrhythmogenic substrates between women and men with NICM. METHODS We analyzed 160 consecutive patients (26 women) with NICM who were undergoing VT ablation at the Hospital of the University of Pennsylvania. Of these 160 patients, 59 (13 women) underwent cardiac magnetic resonance (CMR) before the ablation procedure. The arrhythmogenic substrate was analyzed qualitatively and quantitatively by CMR and/or detailed electroanatomic mapping. RESULTS There were no significant differences in left ventricular scar percentage as defined by CMR (9.5% +/- 7.8% in women vs 11.2% +/- 8.6% in men; P = .5), endocardial bipolar voltage (<1.5 mV; 11.3% +/- 19.3% in women vs 11.5% +/- 16.3% in men; P = .4), endocardial unipolar voltage (<8.3 mV; 38.0% +/- 30.8% in women vs 45.6% +/- 30.9% in men; P = .2), or epicardial bipolar voltage (<1.0 mV; 21.5% +/- 38.9% in women vs 10.7% +/- 13.9% in men; P = .6). There were no significant differences in scar transmurality as defined by CMR (5 categories: endocardial, midwall, epicardial, transmural, and right ventricular endocardial). Similarly, there were no significant differences in scar distribution as defined by CMR or electroanatomic mapping (anteroseptal vs inferolateral). CONCLUSION Scar percentage, transmurality, and distribution are similar between women and men with NICM.