Flecainide is an important addition to the therapeutic armamentarium because it is a potent agent for the treatment of paroxysmal supraventricular tachycardia in patients without structural heart disease. Flecainide also may be useful in patients with debilitating nonsustained ventricular arrhythmias in the absence of structural heart disease. It is rarely useful in the management of life-threatening sustained ventricular arrhythmias.