Results of a prospective randomized study comparing efficacy and safety of refralon and amiodarone for cardioversion in patients with paroxysmal atrial fibrillation and flutter

Aim. To compare efficacy and safety of refralon and amiodarone for cardioversion in patients with paroxysmal atrial fibrillation and flutter (AF/AFL). Methods. The study included 60 patients (32 men and 28 women) with symptomatic paroxysmal AF/AFL. All patients underwent a preliminary examination to exclude contraindications to cardioversion. The procedure of pharmacological cardioversion was carried out in the intensive care unit. By the method of envelope randomization, patients were divided into equal groups of refralon and amiodarone, 30 participants each. Both groups did not differ significantly in terms of main clinical characteristics. Cardioversion with refralon consisted of four subsequent iv injections: 5-5 - 10-10 µg/kg of body weight at intervals of 15 minutes. Patients of the second group were intravenously administered amiodarone at a dose of 5 mg/kg of body weight for 20-60 minutes, depending on the tolerability of the drug. In case of AF/AFL maintaining after 60 minutes from the start of administration, the infusion of amiodarone 100 mg/h continued until restoration of sinus rhythm (SR) or until the maximal total dose of 1200 mg/day was reached. Patients were observed for 24 hours.Results. SR restored in 96.7% (29 of 30) of patients in the refralon group, of which 56.7% (17 of 30) - after a dose of 5 μg / kg. In the amiodarone group SR restored in 53.3% (16 of 30) patients (p<0.001). Median time to arrhythmia conversion in refralon group was 14 [7;23] min, while in amiodarone group it was 150 [82;240] min (p<0.001). Within 60 minutes SR was restored in 26 patients in group of refralon and only in 4 patients in group of amiodarone (p<0.001). There were no statistically significant differences in the incidence of major adverse cardiac events, bradyarrhythmias, lowering of blood pressure, and QT prolongation between the groups.Conclusion. In randomized trial Refralon demonstrated higher rate of successful AF/AFL conversion and shorter time to SR restoration than amiodarone. The most of patients restored SR after administration of the lowest dose of refralon, that ensures the safety of cardioversion.