Vernakalant trumps amiodarone for acute AF termination
MedWire News: Vernakalant - an investigational anti-arrhythmic drug - is more effective than amiodarone in restoring sinus rhythm in patients with recent-onset atrial fibrillation (AF), results from a multinational study indicate.
"Conversion with vernakalant was rapid and significantly more effective than amiodarone," explain A John Camm (St George's University of London, UK) and team in the Journal of the American College of Cardiology.
They continue: "Patients treated with vernakalant had significantly greater symptom relief at 90 minutes and a greater perceived feeling of well-being at 2 hours."
But in a related editorial, Bruce Lindsay (Cleveland Clinic Foundation, Ohio, USA) queried the study's relevance, saying: "One may question why amiodarone was selected as the comparison drug when other studies have shown that amiodarone has low efficacy for conversion of AF."
However, he conceded that "amiodarone is used [in emergency departments] either because it helps to control ventricular rate or because of the misconception that it is effective in converting AF to sinus rhythm. Given these realities, the decision to compare vernakalant with amiodarone seems very relevant."
Camm and team randomly allocated 232 patients (from Australia, Canada, and Europe) with recent-onset AF (duration of 3-48 hours) to receive intravenous (iv) vernakalant (n=116) or iv amiodarone (n=116).
All patients in the vernakalant group received a 10-minute infusion of vernakalant at a dose of 3 mg/kg, followed by a further 10-minute infusion of vernakalant at a dose of 2 mg/kg (if still in AF). This was followed by the administration of two 60-minute infusions of placebo in a second infusion line to ensure maintenance of study blinding.
Patients in the amiodarone group received a 60-minute infusion of amiodarone 5 mg/kg followed by a maintenance 60-minute infusion of amiodarone 50 mg, and a 10-minute infusion of placebo in a second infusion line.
Camm and colleagues found that 10 times as many patients in the vernakalant group compared with the amiodarone group were converted to sinus rhythm within 90 minutes of first exposure to the treatment agent, at 51.7% versus 5.2% (p<0.0001).
Conversion from AF to sinus rhythm was significantly faster among the vernakalant group than the amiodarone group, and more patients who received vernakalant reported symptom relief (palpitations, dyspnea, dizziness, and chest discomfort) at 90 minutes, than those in the amiodarone group, at 53.4% versus 32.8%.
This is equivalent to a 1.63-fold higher likelihood of symptom relief with vernakalant than amiodarone (p=0.0012), say the researchers.
Furthermore, serious adverse effects were rare among all patients, and torsades de pointes, ventricular fibrillation, and sustained ventricular tachycardia did not occur in either treatment group.
Camm and team conclude: "Vernakalant has low pro-arrhythmic potential and provides a rapidly acting therapeutic alternative for the conversion of AF."
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By Lauretta Ihonor