Effect of intravenous amiodarone on QT and T peak-T end dispersions in patients with nonischemic heart failure treated with cardiac resynchronization-defibrillator therapy and electrical storm

Background: The effect of intravenous amiodarone on spatial and transmural dispersion of ventricular repolarization in patients receiving cardiac resynchronization therapy(CRT) remains unclear. Methods: We studied 14 patients with nonischemic heart failure who received CRT with a defibrillator, experienced electrical storm and were treated with intravenous amiodarone. Each patient under went 12-lead electrocardiography( ECG) and 187-channel repolarization interval-difference mapping electrocardiography (187- chRIDM- ECG) before and during the intravenous administration of amiodarone infusion. Results: A recurrence of ventricular tachyarrhythmia was observed in 2 patients during the early period of intravenous amiodarone therapy. Intravenous amiodarone increased the corrected QT interval (from 470752 ms to 508 perpendicular to 55 ms, P = 0.003), but it significantly decreased the QT dispersion( from 107735 ms to 49 +/- 27ms, P = 0.001), T peak-T end(Tp-e) dispersion(from 86 +/- 17 ms to 28 +/- 28 ms, P = 0.001), and maximum inter-lead difference between corrected Tp-e intervals as measured by using the 187- chRIDM- ECG(from 83 +/- 13 ms to 50 +/- 19 ms, P = 0.001). Conclusions: Intravenous amiodarone suppressed the electrical storm and decreased the QT and Tp-e dispersions in patients treated by using CRT with a defibrillator. (C) 2014 Japanese Heart Rhythm Society. Published by Elsevier B.V. All rights reserved.