Effects of Amiodarone on the Electrophysiological Characters of Rabbit Atrial Myocytes

摘要

Amiodarone is a potent antiarrhythmic agent in the treatment of the atrial fibrillation and flutter. However, underlying electrophysiological mechanism are not clarified yet. In the present study, we investigated the acute effects of amiodarone on the action potentials in rabbit atrial myocytes. Amiodarone (10muM) prolonged the action potential durations (APDs) at lower stimulation frequencies (e.g. 38+- 8 ms control vs. 45+-6 ms amiodarone at 0.1 Hz, n=3, P<0.05). In contrast, amiodarone shortened the APDs at higher frequencies (e.g. 81+- 11 ms control vs. 25+-10 ms amiodarone at 3.0 Hz, n=3, P<0.05). These results suggest that the antiarrhythmic action of amiodarone on atrial arrhythmias exhibits frequency-dependence.