Efficacy of Long-term Flecainide Therapy in Patients with Paroxysmal Atrial Fibrillation —Analysis Based on Time of Onset—

This study sought to evaluate the efficacy of long-term flecainide therapy in maintaining sinus rhythms in patients with paroxysmal atrial fibrillation (AF. based on time of onset. Flecainide (150 mg/day. was administered as an antiarrhythmic drug to a total of 70 patients (54 men and 16 women: mean age 65 ± 10 years. after sinus rhythm was restored spontaneously or by electrical and/or pharmacological cardioversion. Paroxysmal AF was divided into three categories based on time of onset: diurnal type (N = 11), nocturnal type (N = 13), and mixed type (N = 46). The mean follow-up period was 37.7 ± 17.7 months. The duration of sinus rhythm maintenance in patients with diurnal and nocturnal paroxysmal AF was 32.4 ± 10.4 months and 20.8 ± 8.3 months, respectively; the duration of sinus rhythm maintenance in those with mixed paroxysmal AF was only 7.2 ± 2.1 months. Significant differences were observed in duration between diurnal and mixed cases (mean ± S.E., P < 0.05). Actuarial recurrence-free rates at 1, 3, 6, 9 and 12 months were 90.9%, 63.6%, 63.6%, 54.5%, and 54.5%, respectively, for diurnal cases; 84.6%, 76.9%, 53.8%, 38.5%, and 30.8%, respectively, for nocturnal cases; and 58.7%, 39.1%, 28.3%, 21.7%, and 15.2% respectively, for mixed cases. Significant differences in rates at 12 months were observed between diurnal and mixed cases (P < 0.05). These results suggest that flecainide is highly effective in preventing AF recurrence in patients with diurnal paroxysmal AF.