Preliminary results of a prospective randomized study comparing the efficacy and safety of refralon and amiodarone in cardioversion in patients with paroxysmal atrial fibrillation and flutter

Aim. To compare the efficacy and safety of chemical cardioversion (CCV) with refralon and amiodarone in patients with paroxysmal atrial fibril­lation and flutter (AF/AFL).

Material and methods. Fifty five patients (mean age, 65±11 years) with paroxysmal AF/AFL were included. All patients underwent a preliminary examination to rule out contraindications to CCV. Further, patients were randomized into groups of refralon (n=30) and amiodarone (n=28), respectively. CCV with refralon was carried out as follows: administration in doses of 5-5-10-10 µg/kg at intervals of 15 minutes. Patients of the second group were intravenously injected with amiodarone at a dose of 5 mg/kg of body weight for 20-60 minutes, depending on the drug tolerability. If AF/AFL persists after 60 minutes, infusion of amio­darone 100 mg/hour until restoration of sinus rhythm (SR) or reaching a dose of 1200 mg/day. Treatment efficacy was assessed by SR reco­very, absence of AF/AFL recurrence, and arrhythmia relief time, and safety was assessed by detection of ventricular arrhythmogenic effects, bradyarrhythmias, blood pressure reduction, and QT interval prolongation. The follow-up period lasted 24 hours.

Results. SR was restored in 96,7% (n=29) of patients in the refralon group, of which 56,7% (n=17) after a dose of 5 mcg/kg. In the amio­darone group, SR was restored in 57,1% (n=16) of patients (p<0,001). The arrhythmia relief time in the refralon group was 14 [7;23] min, while in the amiodarone group — 150 [82;240] min (p<0,001). There were no significant differences in the incidence of bradyarrhythmias, lowering blood pressure, and QT prolongation in the groups.

Conclusion. Refralon demonstrates a higher efficiency and lower time to AF/AFL relief compared with amiodarone, while in most patients, SR recovery occurs after the administration of the lowest doses, which ensures CCV safety.

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