Low dose amiodarone and sotalol in the treatment of recurrent, symptomatic atrial fibrillation: a comparative, placebo controlled study

Abstract

Objective: To assess and compare the safety and efficacy of amiodarone and sotalol in the treatment of patients with recurrent symptomatic atrial fibrillation.

Design: Prospective, randomised, single blind, placebo controlled study.

Setting: Tertiary cardiac referral centre.

Patients: 186 consecutive patients (97 men, 89 women; mean (SD) age, 63 (10) years) with recurrent, symptomatic atrial fibrillation.

Interventions: 65 patients were randomised to amiodarone, 61 to sotalol, and 60 to placebo. Patients receiving amiodarone were maintained at a dose of 200 mg/day after a 30 day loading phase. The sotalol dose was 160-480 mg daily, as tolerated.

Main outcome measures: Recurrence of atrial fibrillation or side effects.

Results: In the amiodarone group, 31 of the 65 patients developed atrial fibrillation after an average of six months, while 15 (11 in sinus rhythm and four in atrial fibrillation) experienced significant side effects after an average of 16 months. In the sotalol group, relapse to atrial fibrillation occurred in 47 of the 61 patients after an average of eight months; three experienced side effects during the titration phase. In the placebo group, 53 of the 60 patients developed atrial fibrillation after an average of four months (p < 0.001 for amiodarone and sotalol v placebo; p < 0.001 for amiodarone v sotalol).

Conclusions: Both amiodarone and sotalol can be used for the maintenance of normal sinus rhythm in patients with symptomatic atrial fibrillation. Amiodarone is more effective but causes more side effects.

Figure 1

Kaplan-Meier curves for (A) the primary analysis and (B) the secondary analysis. Amiodarone and sotalol were superior to placebo. Amiodarone was better than sotalol, but its superiority only became evident after the six month point. When adverse effects are overlooked, amiodarone was seen to be much more effective than the other two agents. There was no difference in the pattern of censoring between the three groups. AF, atrial fibrillation; SE, side effects.

Figure 2

Kaplan-Meier curves for (A) the primary analysis, and (B) the secondary analysis, grouped by sex in the amiodarone group. Female patients had a much better chance of remaining in sinus rhythm for a longer period, but also experienced more side effects than men.

Figure 3

Progression to atrial fibrillation and side effects, with the first month's relapses censored. Amiodarone is now superior to sotalol throughout the period of observation.