AMIODARONE VERSUS QUINIDINE FOR CONVERSION OF RECENT ONSET ATRIAL FIBRILLATION TO SINUS RHYTHM

The safety and efficacy of amiodarone and quinidine in converting recent onset (< 72 hours) atrial fibrillation (AF) to sinus rhythm were compared in 75 patients (35 men, 40 women; mean age, 60 years) referred to our emergency department. There were no statistical differences in age, duration of arrhythmia, left atrial size, underlying cardiac disease, or electrolytic imbalance between the two groups. Amiodarone was administered in continuous intravenous (IV) infusion with an initial dosage of 300 mg over 30 minutes followed by 300 mg every eight hours. Quinidine was orally administered at a dosage of 150 mg every three hours during the first 24 hours and continuing at a dosage of 300 mg every eight hours; an IV digoxin bolus of 0.5 mg was given to all quinidine patients who were not undergoing digitalis treatment. Conversion to sinus rhythm was obtained in 37 of 37 patients in the amiodarone group and in 35 of 38 patients in the quinidine group (NS). The mean time of conversion was 571 +/- 551 minutes for the amiodarone group and 471 +/- 398 minutes for the quinidine group (NS). Minor side effects were observed during amiodarone treatment; two patients taking quindine reported atrial tachycardia resolved by an IV bolus of digoxin. We conclude that both drugs are effective in treating AF; however, amiodarone was safer.