Usefulness of propafenone for recurrent paroxysmal atrial fibrillation.

To evaluate the efficacy of propafenone for suppression of recurrent paroxysmal symptomatic atrial fibrillation (AF), patients with frequent episodes of AF entered an open-label, dose-ranging study to determine the maximal tolerated dose of propafenone and were subsequently randomized to alternate between propafenone and placebo every month for 4 months. Patients recorded each episode of AF in a diary and recorded a simultaneous electrocardiographic rhythm strip by means of a transtelephonic recorder and transmitter to validate the presence of AF. Eighteen patients were eligible for study. During dose ranging, 4 patients withdrew due to inadequate drug efficacy or poor compliance, 2 withdrew due to intolerable side effects and 1 died. The mean dose of propafenone at the end of dose ranging was 644 +/- 189 mg/day. During the crossover study, the percentage of days with an attack of AF was significantly reduced by propafenone compared with placebo (27 +/- 34 vs 51 +/- 34%, p less than 0.01). The rate of early crossover or withdrawal from the crossover study was 13.6% with propafenone and 45% with placebo (p = 0.056). Five patients went on to receive long-term propafenone and 4 continued treatment with suppression of AF for 12 to 21 months. During the crossover study there were 29 reported minor side effects with propafenone and 11 with placebo.