Long-term maintenance of normal sinus rhythm in patients with current symptomatic atrial fibrillation: amiodarone vs propafenone, both in low doses.

STUDY OBJECTIVES To compare the efficacy and safety of amiodarone and propafenone when used for the prevention of atrial fibrillation (AF) and maintenance of normal sinus rhythm in patients with refractory AF. DESIGN Prospective, randomized, single-blind trial. SETTING Tertiary cardiac referral center. PATIENTS One hundred forty-six consecutive patients (72 men; mean age, 63 +/- 10 years [+/- SD]) with recurrent symptomatic AF. INTERVENTIONS We studied 146 patients after restoration of sinus rhythm; patients were randomized to amiodarone, 200 mg/d, or propafenone, 450 mg/d. Follow-up clinical evaluations were conducted at the first, second, fourth, and sixth months, and at 3-month intervals thereafter. The proportion of patients relapsing to AF and/or experiencing side effects was calculated for each group using the Kaplan-Meier method. End point of the study was recurrence of AF or occurrence of side effects necessitating discontinuation of medication. MEASUREMENTS AND RESULTS Of 146 patients, 72 received amiodarone and 74 received propafenone. The two groups were clinically similar. Of the 72 patients receiving amiodarone, AF developed in 25 patients, after an average of 9.8 months, compared to 33 of the 74 patients receiving propafenone after an average of 3.8 months. Twelve patients receiving amiodarone and 2 patients receiving propafenone had side effects necessitating withdrawal of medication while still in sinus rhythm. CONCLUSIONS Amiodarone tends to be more effective than propafenone in maintaining sinus rhythm in patients with AF, but this advantage is offset by a higher incidence of side effects.