OBJECTIVE

To evaluate an effectiveness and safety of the modified refralon injection protocol.

MATERIAL AND METHODS

The study included 100 patients aged 63±12 years with paroxysmal and persistent atrial fibrillation (AF) (53 men). After exclusion of contraindications, all patients received refralon according to the following scheme: initial dose 5 μg/kg and additional dose 5 μg/kg (total dose 10 μg/kg) after 15 min if sinus rhythm (SR) is absent. If AF persisted, additional refralon bolus was administered after 15 minutes (10 μg/kg, total dose 20 μg/kg). Finally, the last bolus of refralon 10 μg/kg was administered after 15 minutes in case of stable AF (maximum total dose 30 μg/kg). All patients were followed-up with ECG control for 24 hours.

RESULTS

SR was restored in 94 out of 100 patients (overall effectiveness 94%). At the same time, 37% of patients restored SR after a minimum dose of 5 μg/kg. Overall effectiveness of dose 10 μg/kg was 65%, 20 μg/kg — 81%. For the first time, the study included patients with paroxysmal AF. All 20 patients with paroxysmal AF recovered SR (efficiency 100%). None patient had life-threatening ventricular arrhythmias. QTc interval prolongation over 500 ms was recorded in 16 patients (16%). In all patients, QTc interval prolongation up to maximum values was noted within 6 hours after injection. Refralon doses 5 and 10 μg/kg were followed by normalization of QTc interval. Bradyarrhythmias after SR recovery were observed in 11 patients (11%) with persistent AF.

CONCLUSION

The modified cardioversion protocol ensures SR recovery in significant number of AF patients using lower doses of refralon. The drug is highly effective for paroxysmal AF. Moreover, SR is restored after injection of the lowest doses in most of these patients. Despite the QTc interval prolongation >500 ms in some patients, Torsades de pointes were not observed in any case.