Effect of Cardiac Resynchronization Therapy on Ventricular Repolarization Parameters and Ventricular Arrhythmias

Abstract

Objective: Cardiac resynchronization therapy (CRT) is commonly used in patients with heart failure (HF) along with left ventricular mechanic and electrical dyssencrony. Left ventricular epicardial pacing in CRT patients changes the normal myocardial activation and increases the transmural dispersion of repolarization. We aimed to investigate the impact of CRT on repolarization parameters and reveal its consequences on arrhythmic events. Materials and Methods: The study consisted of 54 patients treated with CRT. Repolarization parameters; QT, T peak-to-T end and JT, Tpe/QT, QT dispersion and Tpe dispersion were measured. The patients were also investigated in two subgroups according to the presence of ventricular arrhythmias at the end of follow-up. Subgroups were compared in terms of repolarization parameters. Results The change in repolarization parameters according to baseline values were also compared in the whole group.In the whole study group, all of the repolarization parameters significantly increased in the acute phase. In the chronic phase, these abnormalities were significantly diminished. The comparison of the two subgroups did not show any significant difference in respect of repolarization parameters. Conclusion: Epicardial pacing prolongs myocardial repolarization time and increases transmural dispersion of repolarization. However, these abnormalities were transient and were not associated with ventricular arrhythmias.