Amiodarone is now considered to be the most promising drug in the treatment of life-threatening ventricular tachyarrhythmia. 8, 10, 12, 13 This has been approved in many clinical studies on high-risk patient populations including those with postmyocardial infarction and congestive heart failure. 14, 15 Amiodarone has long been referred to as a prototype of class III antiarrhythmic agents, 16, 17 but its pharmacologic action is, in fact, very complex. 18 It prolongs both APD and refractory period when administered over a long period of time. 16, 17 In addition, it has an inhibitory effect on the fast sodium channel as well as slow calcium channel. 19, 20 Amiodarone also has noncompetitive antisympathetic effects, and modulates thyroid function, phospholipid metabolism, and certain cytokine production. 21, 22, 23 Which action or combination of actions is fundamental and salutary for its potent antiarrhythmic activity is not known.