Sex-specific differences in ventricular dyssynchrony at comparable QRS duration: insights from Ultra-High-Frequency ECG
F Klein, Z Zhao, K Curila, K Vernooy, U C Nguyen, L M RademakersAbstract
Objective
Women constitute a minority of patients receiving cardiac resynchronization therapy (CRT), yet demonstrate superior response rates compared to men. It remains unclear whether this disparity involves electrophysiological differences. The purpose of this study is to investigate sex-specific differences in characteristics of CRT recipients using ultra-high-frequency ECG (UHF-ECG).
Methods and results
A total of 345 CRT patients with QRS duration >120 ms (n=240 [70%] men, n=105 [30%] women) were enrolled in a dual-center observational study. Women presented with a significantly higher prevalence of left bundle branch block (LBBB) compared to men (78% vs. 65%), and lower prevalence of right bundle branch block (3% vs. 10%) and intraventricular conduction delay (10% vs. 14%) (p = 0.0256). Non-ischemic cardiomyopathy was more frequent in women than in men (76% vs. 49%, p < 0.001). UHF-ECG was acquired during intrinsic activation. In the entire cohort, QRS duration did not differ between sexes (women 165 ± 20 ms vs. men 168 ± 21 ms, p = 0.104). However, in subgroup analyses in LBBB patients, QRS duration was significantly shorter in women than in men, independent of body surface area and aetiology (women 166 ± 16 ms vs. men 173 ± 19 ms). UHF-ECG ventricular electrical dyssynchrony was defined as the interval between the first and last ventricular activation from V1-V8 chest leads. In the entire cohort, ventricular electrical dyssynchrony did not differ between sexes (women 75 ± 26ms vs. men 71 ± 30ms, p = 0.224), nor in the LBBB or non-LBBB subgroups. After stratification by QRS duration, women exhibited higher ventricular electrical dyssynchrony than men in the 140–159 ms (69 vs. 54 ms, p = 0.008) and 160–179ms (84 vs. 75 ms, p = 0.022) subgroups, while no differences were observed in the 120–139ms or ≥180 ms groups.
Conclusion
Women showed a higher prevalence of LBBB and non-ICM, and, when LBBB was present, exhibited shorter QRS durations than men. In subgroup analyses of QRS durations between 140-179 ms, women demonstrated greater ventricular electrical dyssynchrony compared with their male counterparts. These findings may explain the superior response to CRT observed in women.Central illustration