Clinical efficacy of flecainide acetate in atrial fibrillation.

Seventy-seven patients with symptomatic atrial fibrillation (AF) received oral flecainide acetate (247 +/- 8 mg/day). In 66 patients, previous antiarrhythmic trials consisted of 1-9 drugs. In 55 cases, AF was paroxysmal. It was persistent in 22 patients. Conversion and/or no recurrence of AF was achieved in 40 patients (52%) by flecainide alone and in 11 (14%) by the combination of flecainide and amiodarone. The mean flecainide serum level was 535 +/- 46 ng/ml. Age, presence of coronary artery disease or electrocardiographic parameters were not useful for predicting clinical response. In persistent AF, flecainide efficacy decreased with the duration of arrhythmia. Side effects concerned conduction (26%) and congestive heart failure (5%).