Ibutilide is a class III antiarrhythmic drug and works via enhancement of the slow inward sodium current, unlike other class III agents that are cardiac potassium channel blockers.

Ibutilide can be used as a one time intravenous infusion to cardiovert atrial fibrillation or atrial flutter to sinus rhythm chemically.

Ibutilide is successful in restoring sinus rhythm in almost half of cases. The major risk is QT interval prolongation which can result in polymorphic ventricular tachycardia (Torsades de Pointes) in about 2% of cases.