The efficacy and safety of vernakalant, a relatively atrial-selective antiarrhythmic agent, in converting atrial fibrillation (AF) to sinus rhythm (SR) were evaluated in this multicenter, open-label study of patients with AF lasting >3 hours and ≤45 days (RCT no. NCT00281554).

Adult patients with AF and an indication for conversion to SR received a 10-minute intravenous infusion of vernakalant (3 mg/kg). If after a 15-minute observation period AF was present, a second 10-minute infusion of intravenous vernakalant (2 mg/kg) was given. The primary efficacy end point was the proportion of patients with recent-onset AF (AF lasting >3 hours to ≤7 days) who converted to SR within 90 minutes of the start of the first infusion. Safety evaluations included vital signs, telemetry and Holter monitoring, 12-lead electrocardiography, clinical laboratory tests, physical examinations, and adverse events (AEs).

A total of 236 hemodynamically stable patients with AF received intravenous vernakalant. Among them, 167 (71%) had recent-onset AF and were eligible for the primary efficacy end point. Vernakalant rapidly converted recent-onset AF to SR in 50.9% of patients, with a median time to conversion of 14 minutes among responders. The most common AEs were dysgeusia, sneezing, and paresthesia. These occurred at the time of vernakalant infusion, were transient, and resolved spontaneously. Ten patients (4.2%) discontinued vernakalant treatment because of AEs, most commonly (in 4 of 10) hypotension. There were no episodes of torsades de pointes, ventricular fibrillation, or sustained ventricular tachycardia.

Vernakalant rapidly converted recent-onset AF to SR, was well tolerated, and may be a valuable therapeutic alternative for reestablishing SR in patients with recent-onset AF.