Flecainide acetate in the prevention of paroxysmal atrial fibrillation: a nine-month follow-up of more than 500 patients.

In order to assess efficacy, safety, and long-term tolerance of flecainide for the prevention of paroxysmal atrial fibrillation (PAF), 944 patients (555 male) were enrolled in an open multicenter study. All patients had had greater than or equal to 1 episodes of atrial fibrillation and were in sinus rhythm at the time of entry. The mean age was 65.3 +/- 11 years, and 43% of patients had no detectable heart disease. The mean daily dose of flecainide was 190 +/- 34 mg. Clinical examination, electrocardiogram (ECG) and 24-hour Holter monitoring were performed at entry into the study and on months 3, 6, and 9. Of the patients, 189 were lost to follow-up. Of the remaining 755 patients, 562 (74%) continued the treatment during the 9-month period and 193 (26%) dropped out. A total of 84 adverse effects were reported in 7.6% enrolled patients and in 9% of patients during follow-up, with treatment interruption in 50% of the cases. There were only 3 minor cardiovascular side effects, all leading to treatment discontinuation. No deaths in patients with recurrent PAF and no proarrhythmic events were reported. Flecainide appears to be effective in preventing PAF, with 65% of patients being arrhythmia-free after 9 months of treatment at a mean daily dose of 200 mg. Side effects were common, but clinically significant adverse events were infrequent.