Efficacy and tolerability of oral propafenone versus quinidine in the treatment of recent onset atrial fibrillation: A randomized, prospective study.

BACKGROUND: A prospective, randomized study was conducted to evaluate the efficacy and tolerability of oral propafenone and quinidine for the conversion of paroxysmal atrial fibrillation (AF).

METHODS: Eighty one consecutive patients (female/male 46/35; mean age 64.0 +/- 11.6), admitted to hospital with AF lasting no longer than 48 hours, were randomized in terms of their pharmacological therapy. Forty three patients (55%) were randomly assigned to Group I and received propafenone 600 mg orally as the initial therapy, with an additional dose of 300 mg after eight hours, if the sinus rhythm had not been restored by then. Thirty eight patients (45%) (Group II) received 1 mg digoxin IV followed by an oral loading of quinidine (400 mg followed by 200 mg every two hours).

RESULTS: The conversion rate assessed after 24 hours was the same in both groups (Gr. I vs. Gr. II: 90.7 vs. 91.4%), with the same number of mild side effects (Gr. I vs. Gr. II: 37.2% vs. 45.7%). No life-threatening adverse events were reported. Propafenone achieved a higher efficacy rate during the first eight hours (83.3 vs. 54.3%; p = 0.01), with a significantly shorter time required to sinus rhythm recovery throughout the study period, with a median time of 165 min (95% confidence interval 120-278) vs. 360 min (95% confidence interval 298-650; p < 0.05). There was some indication of greater effectiveness of propafenone than quinidine in early sinus rhythm restoration in patients with: no structural heart disease, in those with an AF duration shorter than 12 hours, and in patients with an ejection fraction > 55%.

CONCLUSIONS: Although both drugs revealed the same effectiveness, the conversion to sinus rhythm in the group treated with propafenone was observed more quickly despite the longer paroxysmal AF episode duration.