[Effectiveness and side effects of the treatment with propafenone and flecainide for recent-onset atrial fibrillation].

BACKGROUND: The authors report their experience in recent-onset atrial fibrillation treated with intravenous flecainide and propafenone, in comparison with the placebo group. METHODS: We randomized 352 (138 in the flecainide group, 164 in the propafenone group and 50 in the control group) consecutive patients (167 males, 185 females, mean age 59 +/- 12 years) with recent-onset atrial fibrillation. The electrocardiogram of all patients was monitored for at least 24 hours. RESULTS: The restoration of sinus rhythm occurred in 72.5, 80.4, 86.2 and 89.8% of patients in the flecainide group; in 54.3, 68.3, 75 and 92.1% in the propafenone group; in 22.2, 27.8, 35.2 and 46.3% in the control group, at 1, 3, 6 and 24 hours respectively. The occurrence of side effects was the same in all treatment groups, and occurred in about 10% of patients in the flecainide and propafenone groups, and in 4% in the control group. In our study population the treatment of recent-onset atrial fibrillation with flecainide was faster in converting the arrhythmia to sinus rhythm (p < 0.005 at 1 hour, p < 0.05 at 3 hours, p = 0.05 at 6 hours). However within 24 hours the efficacy of either flecainide or propafenone was the same (p = NS at 24 hours). CONCLUSIONS: Side effects were similar in both treatment groups. In particular malignant arrhythmias did not occur in the treatment groups and in the control group.