Fixed dose of сavutilide versus propranolol in patients with paroxysmal atrial fibrillation and flutter

Aim. To evaluate the efficacy and safety of a single intravenous fixed dose of cavutilide 350 μg compared to propranolol in patients with paroxysms of atrial fibrillation (AF) and atrial flutter (AFl)

Material and methods. 70 patients with paroxysmal AF/AFl (36 women and 34 men, mean age 64.8±10.6 years) were divided into two groups. In the first group (n=35) a single intravenous injection of cavutilide 350 μg was administered to restore sinus rhythm (SR). In the second group (n=35) rate-control therapy with propranolol (10-20 mg per os every 3-4 hours) was performed. The main endpoints were SR restoration within 60-min and 24h, time to arrhythmia termination, and absence of AFib/AFl relapses. Safety was assessed by monitoring for major adverse cardiovascular events and proarrhythmia.

Results. Within the first 60-min period SR was restored in 77.1% of patients in cavutilide group and in none of the patients in propranolol group (0; p<0.001). SR was restored in 100% of patients with AFl (n=7) within 1 hour after cavutilide administration. After 24h SR was restored in 88.6% of patients in group of cavutilide versus 45.7% of patients in propranolol group (p<0.001). Median time to SR restoration was 8,0 [5,0; 13,0] minutes in cavutilide group versus 375,0 [232,0; 915,0] minutes in propranolol group (p<0.001). A decrease in heart rate of more than 10 beats/min was observed in 3 out of 4 patients (75%) who did not restore SR after administration of cavutilide, and in 28 out of 35 patients in propranolol group (75% vs 80%; p=0.41). There were 2 cases of asymptomatic decrease in heart rate <50 beats/min. and 3 cases of transient prolongation of QT >500 ms after cavutilide administration. In all 3 cases QT interval decreased to normal values within 1 hour. No AF/AFl recurrencies, proarrhythmia and major adverse cardiovascular events occurred in both groups.

Conclusion. A single fixed dose of cavutilid 350 μg is safe and highly effective for restoration of SR in paroxysmal AF/AFl, outperforming propranolol in likelihood of SR recovery, time to relief, and relapse prevention. Notably SR recovery after administration of cavutilide in 100% of patients with AFl, who are characterized by extremely low efficacy of other antiarrhythmic drugs. The high efficiency and rapid achievements of results, without significant adverse events, indicate the potential prospects for the use of a fixed dose of cavutilide 350 mg in outpatient settings.

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