Clinical course of recent-onset atrial fibrillation treated with oral propafenone.

Atrial fibrillation (AF) is one of the most common cardiac arrhythmias in the adult population. Propafenone is a class 1c antiarrhythmic agent that has an electrophysiologic profile suggesting that it might be potentially effective in recent-onset AF. The present study was undertaken, therefore, to examine the time course as well as the frequency of successful conversion in patients with recent-onset AF treated with propafenone administered orally. Fifty patients with recent-onset AF were recruited into 2 groups: 25 patients were given propafenone, 150 mg every 4 h, and 25 patients served as a control group and received verapamil (a drug known to slow the ventricular response but not to restore sinus rhythm) 40 mg, every 4 h and up to 48 h or until conversion to sinus rhythm occurred. Of the 50 patients, 2 refused to continue the study and another 2 were excluded because of left heart failure. Conversion to sinus rhythm occurred in 21 of 24 patients (87 percent) in the propafenone group as compared with 9 of 22 (41 percent) in the verapamil group (p < 0.001). In 10 patients in the propafenone group, conversion occurred within 12 h, within 24 h in another 9 patients, and between 24 and 48 h in the remaining 2 patients. There was no correlation between the duration of AF prior to entry into the study and the subsequent incidence of and time to conversion with propafenone. With respect to cause of AF, all groups showed a high incidence of conversion. Two patients developed heart failure during treatment and one patient (in the verapamil group) developed embolic stroke while still having atrial fibrillation. We conclude that in patients with AF, the prognosis for conversion to sinus rhythm within 48 h, with propafenone, is excellent (87 percent) and safe.