Amiodarone versus propafenone for conversion of chronic atrial fibrillation: Results of a randomized, controlled study

OBJECTIVES The purpose of this study was to investigate the efficacy and sa fety of amiodarone and propafenone in the conversion of chronic atrial fibr illation in a prospective, randomized placebo-controlled study. BACKGROUND The effectiveness of amiodarone and propafenone in the treatment of patients with chronic atrial fibrillation has not been adequately studi ed. METHODS One hundred one patients (48 men, mean age 64 +/- 9 years) with atr ial fibrillation lasting >3 weeks participated in the study. Thirty-four pa tients received amiodarone (300 mg intravenously over 1 h, followed by 20 m g/kg over the next 24 h plus 600 mg orally, in three doses, for 1 week, the n 400 mg/day orally, for three weeks), 32 received propafenone (2 mg/kg int ravenously over 15 min, followed by 10 mg/kg over 24 h and then 350 mg/day orally, for one month) and the remaining 35 served as control subjects. All patients received digoxin and anticoagulant treatment as indicated (Intern ational Normalized Ratio 2 to 3). RESULTS Conversion to sinus rhythm was achieved in 16 (47.05%) patients who received amiodarone, in 13 (40.62%) who received propafenone and in none o f the control subjects (p < 0.001 for both groups vs. control subjects). Th ose who converted had smaller atria than those who did not and atrial fibri llation of shorter duration in both the amiodarone and propafenone groups. Treatment was discontinued in one patient of the propafenone group because of significant QRS widening. CONCLUSIONS Amiodarone and propafenone appear to be safe and equally effect ive in the termination of chronic atrial fibrillation. Left atrial diameter and arrhythmia duration are independent predictors of conversion. (J Am Ce ll Cardiol 1999;33:966-71) (C) 1999 by the American College of Cardiology.