Amiodarone-induced torsades de pointes.

Five cases of amiodarone-induced syncope due to torsades de pointes or ventricular fibrillation are described. Amiodarone was used for recurrent supraventricular tachycardia in four cases and frequent ventricular extra systoles complicating congenital QT prolongation in the remaining case. Each was associated with a marked prolongation in the QTc interval following amiodarone. Three cases had had a previous history of life-threatening ventricular arrhythmias secondary to anti-arrhythmic drugs. Hypokalemia may have been a contributory factor in two. The clinical features, predisposing factors, and treatment are discussed.