Efficacy of amiodarone for the termination of persistent atrial fibrillation.

ABSTRACT

The efficacy and safety of amiodarone in the conversion of persistent atrial fibrillation (AF) were investigated in a prospective, randomized, controlled study. Of 67 consecutive patients (32 men, mean age 64+/-9 years) with AF lasting >48 hours, 33 received amiodarone and 34 received placebo. Baseline clinical characteristics were similar in the 2 groups. Patients randomized to amiodarone received 300 mg intravenously for 1 hour and then 20 mg/kg for 24 hours. They were also given 600 mg/day orally, divided into 3 doses, for 1 week and thereafter 400 mg/day for 3 weeks. Patients randomized to placebo received an identical amount of saline IV over 24 hours and then oral placebo for 1 month. Conversion to sinus rhythm was achieved in 16 of the 33 patients (48.5%) who received amiodarone and in none of the 34 patients in the placebo group (p <0.001). None of the patients converted to sinus rhythm within the first 3 days. Those who converted had smaller atria than those who did not (diameter 41.9+/-7.2 vs 50.4+/-5.7 mm, p <0.001). Sex, age, baseline heart rate, left ventricular ejection fraction, and the duration of AF did not differ significantly between patients who converted and those who did not. No side effects requiring discontinuation of treatment were observed in either group. Amiodarone, administered both intravenously and orally, appears to be safe and effective in the termination of persistent AF. Left atrial diameter is the sole independent predictor of conversion.