LOW-DOSE AMIODARONE FOR ATRIAL-FIBRILLATION

Concerns about proarrhythmia risk and inefficacy associated with class I antiarrhythmic drugs have revived interest in low-dose amiodarone ( maintenance dose 200-400 mg/day) for suppression of atrial fibrillatio n. In nonrandomized trails of amiodarone for atrial fibrillation refra ctory to conventional agents, amiodarone has been successful in mainta ining sinus rhythm in 53-79% of patients during a mean follow-up of 15 -27 months. Intolerable side effects, including pulmonary toxicity, ar e in the range of 1-12% per year and resolve following amiodarone with drawal in the majority of cases. Proarrhythmia risk associated with am iodarone, even in the setting of left ventricular dysfunction, is extr emely low. In patients with congestive heart failure, in whom other ph armacologic options are limited by proarrhythmia risk and negative ino tropism, preliminary experience with amiodarone is especially promisin g. Randomized trials are needed, directly comparing amiodarone to conv entional antiarrhythmic therapy for atrial fibrillation suppression an d comparing amiodarone to warfarin for thromboembolism prevention in p atients with atrial fibrillation refractory to conventional antiarrhyt hmic drugs.