Amiodarone-induced torsades de pointes: the possible facilitatory role of digoxin

Poorly controlled supraventricular arrhythmias in a hypokalaemic 74 year old woman were treated with oral amiodarone. This caused torsades de pointes, and was preceded by marked prolongation of the QT interval. The induction of torsades de pointes by amiodarone is thought to be an idiosyncratic reaction to amiodarone itself which is facilitated by electrolytic abnormalities. The present case, however, indicates the possibility of a pro-arrhythmic effect secondary to an interaction between amiodarone and digoxin.