Time course of fibrillation and defibrillation thresholds after an intravenous bolus of amiodarone--an experimental study.

Unlabelled: Experimental studies have described an increase in ventricular fibrillation threshold (VFT) by intravenous amiodarone. The aim of this study was to examine the early time course of changes in VFT and defibrillation thresholds (DFT) after an intravenous bolus of amiodarone in an experimental pig model of transient myocardial ischemia.

Methods And Results: VFT and relative effective ventricular refractory period (ERP) were measured in 15 anaesthetized open-chest pigs after 3 min of regional coronary ischaemia before (time 0) and 2, 15, 30, 60, and 90 min after the intravenous injection of normal saline (group A, n = 5) or amiodarone, 5 mg/kg over 15 s (group B, n = 10).