Relationship between ventricular dyssynchrony and T-wave alternans in patients with coronary artery disease.

INTRODUCTION: Coronary artery disease (CAD) is associated with increased dispersion of repolarization and sudden cardiac death. We sought to investigate whether ventricular dyssynchrony is associated with proarrhythmic repolarization dispersion as measured by T-wave alternans (TWA) in patients with CAD. METHODS AND RESULTS: We evaluated 154 patients (67 ± 9 years, 123 men) with documented CAD, who underwent exercise treadmill testing and echocardiographic examination. TWA was analyzed continuously during treadmill testing in all standard precordial leads by time-domain method. Tissue Doppler imaging was performed to measure inter- and intraventricular dyssynchrony. Increased TWA ≥ 60µV was observed in 42 (27%) patients. There was higher prevalence of females (31 vs 16%, P = 0.04) and greater body mass index (25.7 ± 2.6 vs 24.6 ± 3.0 kg/m², P = 0.04) in the TWA ≥ 60µV group of patients than theTWA< 60µV group. The index of interventricular dyssynchrony, Ts-RL, was significantly increased (75.6 ± 37.8 vs 59.9 ± 35.9 ms, P = 0.03) but not intraventricular dyssynchrony (all P > 0.05) in patients with TWA ≥ 60 µV compared with those with TWA < 60 µV. In addition, a weak but significant positive correlation was observed between TWA and Ts-RL (r = 0.25, P = 0.003). Multivariate analysis revealed that only Ts-RL (odds ratio 1.02, 95% confidence interval 1.00­1.03, P = 0.013) was independent predictor for increased TWA. CONCLUSIONS: Our results demonstrated that interventricular dyssynchrony in patients with CAD is associated with increased TWA. This suggests that interventricular dyssynchrony may contribute to proarrhythmic repolarization dispersion.