Vernakalant is a new antiarrhythmic drug that acts selectively in the atrium, targeting atrial specific channels. Vernakalant is an anti-arrhythmic medicine that acts preferentially in the atria by prolonging atrial refractoriness and by rate-dependently slowing impulse conduction. These anti-fibrillatory actions on refractoriness and conduction are thought to suppress reentry, and are potentiated in the atria during atrial fibrillation. The preferential effects of vernakalant on the atria are postulated to result from its block of currents that are expressed in the atria (e.g., the ultra-rapid delayed rectifier potassium current; and the acetylcholine-activated potassium current), but not in the ventricles, as well as the unique electrophysiologic condition of the fibrillating atria. An oral formulation of vernakalant is in phase II development as a long-term maintenance therapy for patients with atrial fibrillation. An intravenous formulation of vernakalant has been launched in most countries in Europe and Latin America, and in Hong Kong, for the acute conversion of atrial fibrillation. The product has been approved for the acute conversion of atrial fibrillation in South Africa, Iceland, Turkey and is awaiting approval for the same indication in Canada. Phase III development of the IV formulation is ongoing at sites in Asia, and development is currently on hold in the US.