EFFECTIVENESS OF LOADING ORAL FLECAINIDE FOR CONVERTING RECENT-ONSET ATRIAL-FIBRILLATION TO SINUS RHYTHM IN PATIENTS WITHOUT ORGANIC HEART-DISEASE OR WITH ONLY SYSTEMIC HYPERTENSION

Sixty-two patients with recent-onset (less-than-or-equal-to 1 week) atrial fibrillation (New York Heart Association functional class 1 and 2) were randomized in a single-blind study to 1 of the following treatment groups: (1) flecainide (300 mg) as a single oral loading dose; or (2) amiodarone (5 mg/kg) as an intravenous bolus, followed by 1.8 g/day; or (3) placebo for the first 8 hours. Twenty-four-hour Holter recording was performed, and conversion to sinus rhythm at 3, 8, 12 and 24 hours was considered as the criterion of efficacy. Conversion to sinus rhythm was achieved within 8 hours (placebo-controlled period) in 20 of 22 patients (91%) treated with flecainide, 7 of 19 (37%) treated with amiodarone (p <0.001 vs flecainide), and 10 of 21 (48%) treated with placebo (p <0.01 vs flecainide). Resumption of sinus rhythm within 24 hours occurred in 21 of 22 patients (95%) with flecainide and in 17 of 19 (89%) with amiodarone (p = not significant). Mean conversion times were shorter for flecainide (190 +/- 147 minutes) than for amiodarone (705 +/- 418; p <0.001). No major side effects occurred. At Holter monitoring, a pause of 9.3 seconds was observed in 1 asymptomatic patient treated with flecainide. Phases of atrial flutter with a ventricular rate less-than-or-equal-to 150 beats/min were detected before sinus conversion in 1 patient receiving placebo and in 2 receiving flecainide. In conclusion, flecainide administered orally in a single loading dose is highly effective in converting recent-onset atrial fibrilation to sinus rhythm and is more rapid than is intravenous amiodarone. This in-hospital regimen in patients without major organic heart diseases was safe and well-tolerated.