Purpose: To evaluate differences between amiodarone, procainamide and quinidine in the time delay necessary to convert acute atrial fibrillation (AF) to sinus rhythm.
Methods: Sixty patients with acute AF were randomized in three groups (G) and treated with: quinidine (QG)-(21 patients) i.v. digital + quinidine up to 600 mg; procainamide (PG)-(23 patients) i.v. digital + i.v. procainamide, 10 mg/kg; amiodarone (AG)-(16 patients) i.v. amiodarone, 5 mg/kg. To evaluate time delay to conversion, all patients have their rhythm recorded by Holter system during four hours. Statistics were done with x2, considering significant a p < 0.05.
Results: There were no differences between groups regarding to age, gender and delay from symptoms initiation and medical assistance. Conversion to sinus rhythm occurred, in QG-71.4% cases; PG-47.8% and AG-50% (p > 0.05). Time delay in minutes to conversion were, respectively (media +/- SD): QG-112 +/- 43; PG-44.1 +/- 28; AG-20 +/- 13, significantly lower in PG and AG related to QG (p = 0.001). Although not significant, side effects were observed mostly in PG.
Conclusion: Amiodarone is a good choice to convert, very quickly, acute AF. Otherwise, quinidine has the best rate of conversion but with a longer time delay.