Influence of cardiac resynchronization therapy on dispersion of repolarization and ventricular arrhythmia at different times

Abstract

Objective To determine the time-dependent effect of cardiac resynchronization therapy(CRT) on dispersion of repolarization and ventricular arrhythmia in heart failure patients. Methods A total of 62 consecutive patents who underwent their first cardiac resynchronization therapy defibrillator(CRT-D) implantation at arrhythmia center of Fuwai Hospital from January 2007 to December 2014 were studied.The electrocardiograms were collected at pre-operation, immediate post operation, 1, 3, 6, and 12 months after device implantation respectively and were analyzed for T-peak to T-end(TpTe). Ventricular tachycardia(VT)/ventricular fibrillation(VF) episodes were obtained through the pacemaker records.Left ventricular(LV) reverse remodeling was defined as the left ventricular end-diastolic dimension(LVEDD) decreased by at least 10%.Changes of TpTe at different periods and VT/VF episodes were compared between LV reverse remodeling and non-reverse remodeling groups. Results TpTe decreased significantly at 6 and 12 months after CRT-D implantation [(105.32±11.32) ms at baseline vs.(101.06±10.61) ms at 6 months(P<0.05)vs.(99.5±11.44) ms at 12 months(P<0.05)]. LV reverse remodeling group demonstrated a great reduction of TpTe at 6 and 12 months after CRT-D implantation and had a lower rate of VT/VF episodes(compared with non-reverse remodeling group, log-rank test, χ2=4.287, P=0.038). Conclusion After CRT-D implantation, TpTe and the number of VT/VF episodes decreased over time. The patients with LV reverse remodeling had a grearter reduction of transmural dispersion of repolarization and a lower rate of VT/VF episodes. Key words: Cardiac resynchronization therapy; T-peak to T-end; Dispersion of repolarization