Ventricular arrhythmias: - Treatment of life-threatening ventricular tachyarrhythmias; - Treatment of symptomatic non-sustained ventricular tachyarrhythmias. Supraventricular arrhythmias: - Prophylaxis of paroxysmal atrial tachycardia, paroxysmal atrial fibrillation, paroxysmal A-V nodal re-entrant tachycardia, paroxysmal A-V re-entrant tachycardia using accessory pathways, and paroxysmal supraventricular tachycardia after cardiac surgery; - Maintenance of normal sinus rhythm following conversion of atrial fibrillation or atrial flutter.