The safety and efficacy of
amiodarone and
propafenone in converting
atrial fibrillation or flutter after cardiac surgery were compared in a randomized double-blind trial. Eighty-four patients with sustained atrial
tachyarrhythmias of more than 30 min' duration, stable hemodynamic status and neither preoperative atrial arrhythmias nor treatment with other antiarrhythmis drugs, were randomized to receive
amiodarone (46 patients: 5 mg/kg over 15 min and then 15 mg/kg over the subsequent 24 h for non-converting) or
propafenone (38 patients: 2 mg/kg over 15 in and then 10 mg/kg over the subsequent 24 h for non-converting). Nine of the 46 patients (19.5%) receiving
amiodarone converted to sinus rhythm within 1 h following bolus injection compared with 17 of 38 patients (44.7%) treated with
propafenone (P < 0.05). Within the 24 h study, 38 of 46 patients (82.6%) given
amiodarone and 26 of 38 patients (68.4%) given
propafenone were converted to sinus rhythm (P = NS). A significantly progressive reduction in ventricular response, already evident at 10th min from the start of treatment, was achieved in both groups of patients. Side effects occurred in six patients given
propafenone (15.7%) and in five given
amiodarone (10.8%) (P = NS). The two drugs were equally effective in converting postoperative
atrial fibrillation and/or flutter after 24 h although
propafenone was superior within the first hour.