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 inerval
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