Flecainide versus amiodarone in preventing paroxysmal idiopathic atrial fibrillation

Aim of this study was to compare the efficacy of flecainide (F) and amiodarone (A) in preventing paroxysmal idiopathic atrial fibrillation (PIAF). Forty-two pts (32M, 12F, 51 ± 9 years) with documented PIAF (2 episodes/month at least) were studied. At the beginning of the study all patients were on sinus rhythm and none was on antiarrhythmic therapy. Twelve-leads ECG, 2D-echo, x-ray, laboratory evaluation including thyroid function, were obtained in all patients at baseline, at 3-12-18 month follow-up. The patients were randomly assigned to F (200-300 mg/day) -24 pts- or to A (200-400 mg/day, 5 days a week after loading) -18 pts-. After failure of the first treatment (recurrence or drug intolerance) the patients crossed-over to the second drug. At month 3, 88% pts on F continued F (three patients crossed-over for recurrences); 94% pts on A continued A (one patient crossed-over for intolerance). At month 12, 83 pts were on F (one cross-over for recurrences), 89% were on A (one drop-out). At month 18, 83% pts were on F, 67% on A (3 pts crossed-over, 1 for recurrence, 2 for intolerance, 1 dropped out). PIAF was resistant to both drugs in 4 pts (recurrences). Thyroid function alteration was observed in 4 pts on A, no side effects on F. No significant variations in ECG, echo and x-ray were documented. In convlusion, F is more effective and safer than A in preventing PIAF in long-term follow up.