Abstract 2860: Efficacy and Safety of Vernakalant Hydrochloride Injection for the Treatment of Atrial Fibrillation After Valvular or Coronary Artery Bypass Surgery
Introduction: Postoperative atrial fibrillation (AF) and atrial flutter (AFL) are common after cardiac surgery. This study evaluated the efficacy and safety of vernakalant hydrochloride, a novel atrial selective, frequency- and voltage-dependent Na+ and early activating K+ channel blocker, in converting AF or AFL to normal sinus rhythm (SR) after coronary artery bypass surgery (CABG), valvular surgery, or both.
Methods: This multicenter, double-blind, randomized, placebo-controlled trial included patients aged ≥18 years who had normal SR preceding surgery; had undergone CABG or valvular surgery; and had documented, sustained (3–72 hours) AF or AFL between 24 hours and 7 days after CABG or valvular surgery. Patients were randomly assigned in a 1:2 ratio to receive a 10-min infusion of placebo or vernakalant 3 mg/kg. After 15 min, a second 10-min infusion of placebo or vernakalant 2 mg/kg was given, if AF or AFL persisted. Postdose evaluations included 24-hr Holter monitoring, 12-lead ECG recordings, and assessment of vital signs and AF/AFL symptoms. The primary efficacy measure was conversion to SR for at least 1 minute within 90 min of first exposure.
Results: Of 190 patients randomized, 161 received treatment (54 placebo and 107 vernakalant). The main reason for not receiving treatment was spontaneous conversion to SR (7 placebo and 17 vernakalant). Among the patients given treatment, 67% had undergone CABG, 24% had valvular surgery, and 9% had both. The mean age was 68 years, and most patients were men (75%) and white (94%). At entry, 93% of patients had AF, 6% had AFL, and 1% had neither. Conversion to SR within 90 minutes was observed in 45% of patients given vernakalant and 15% of those given placebo (P = .0002). Of the patients converting to SR with vernakalant, the median time to conversion was 12 minutes and 75% converted on the first dose. In the 24-hr period following study drug administration, adverse events were reported in 32% and 38% of patients given placebo and vernakalant, respectively, of which 2 were serious (complete AV block and hypotension) in the vernakalant group. There were no deaths or cases of torsade de pointes.
Conclusions: Vernakalant was effective and well tolerated in the conversion of AF and AFL to SR after CABG, valvular surgery, or both.