Cavutilide (fixed dose) versus amiodarone in paroxysmal atrial fibrillation

Aim. The purpose of this study is to compare the single use of a fixed minimum dose of cavutilid (refralon; Russian Federation, E.I. Chazov National Medical Cardiology Research Centre) 350 μg with amiodarone in patients with paroxysms of atrial fibrillation and flutter. Materials and methods. The study included 62 patients with paroxysmal atrial fibrillation and flutter, divided into two groups (31 patients each). The first group received single fixed dose of cavutilid 350 μg, the second — amiodarone at a starting dose of 5 mg / kg with a possible continuation of the infusion up to 1200 mg in case of failure to achieve sinus rhythm recovery. The patients did not differ in main clinical and instrumental parameters, except for the higher weight and duration of medical history in the amiodarone group. The effectiveness of cardioversion (restoration of sinus rhythm within 1 and 24 hours, time to restoration of sinus rhythm, reduction of heart rate, achievement of " lenient " heart rate control, absence of sustained relapses) and safety (presence of serious cardiovascular complications, ventricular arrhythmias, prolongation of QT/QTc intervals, severe bradycardia and pauses >3,0 sec, arterial hypotension). Results. In the cavutilid group, sinus rhythm restoration within 1 hour was achieved in 87.1% of patients, in the amiodarone group — in 19.4% (p<0.001). After 24 hours, sinus rhythm was registered in 93.3% and 64.5%, respectively (p=0.011). Time to sinus rhythm restoration was significantly faster in patients of the cavutilid group (median 8.00 [5.00; 13.00] minutes versus 140.00 [60.75; 240.00] minutes for amiodarone; p<0.001). The arrhythmia recurrence rate, heart rate reduction, and achievement of "linient" frequency control did not differ statistically between the groups compared. Major adverse cardiovascular events and ventricular tachycardia were not reported in any of the groups. Prolongation of the QT/QTc interval was less common (in 2 patients, 6.5%, versus 5 patients, 16,1%; p=0,425) and lasted significantly less time after the use of cavutilid. Arterial hypotension was observed in 2 patients (6.5%) only in the amiodarone group. Discussion. The high efficacy and safety of a single fixed dose of cavutilid 350 μg for pharmacological cardioversion of atrial fibrillation and flutter paroxysms demonstrate low risk of arrhythmogenic effects of the drug and the possibility of reducing patient follow-up time both in intensive care units and in general inpatient setting. Taking these advantages into consideration, we may suggest that fixed dose of cavutilid 350 μg has potential for outpatient use.