Novel agents for the acute conversion of atrial fibrillation: focus on vernakalant

Vernakalant is a novel anti-arrhythmic drug, recently approved for the cardioversion of recent-onset atrial fibrillation. Its action is mainly due to the blockade of atrial-selective channels responsible of the ultra-rapid delayed rectifier current I(Kur), but has also important interactions with other channels and currents, such as I(Na) (inward sodium current), and I(KACh) (acetylcholine-regulated potassium current). Due to the relatively selective blockade of the I(Kur), vernakalant prolongs the effective refractory period of the atria with minimal effects on the ventricles, thus minimizing the risk of proarrhythmia. Thus far vernakalant has been tested in three placebo-controlled trials (ACT I, ACT II and ACT III) and in one amiodarone-controlled study (AVRO). Vernakalant has been demonstrated more effective than both placebo and amiodarone for the rapid conversion of atrial fibrillation, without significant adverse events. This article will review the recent patents on this novel atrial-selective agent, discussing its mechanisms of action and possible clinical applications in the real-world practice.