Ibutilide Fumarate is a Class III antiarrhythmic agent that is indicated for acute cardioconversion of atrial fibrillation and atrial flutter of a recent onset to sinus rhythm. It exerts its antiarrhythmic effect by induction of slow inward sodium current, which prolongs action potential and refractory period (physiology) of myocardial cells. Because of its Class III antiarrhythmic activity, there should not be concomitant administration of Class Ia and Class III agents.
Administration resulted in successful heart rhythm control in 31-44% of patients within 90 minutes, with sustained polymorphic ventricular tachycardia in 0.9-2.5% of patients. It appears to show better results in atrial flutter as compared to atrial fibrillation.