Torsade de pointes with amiodarone in a patient with previous torsade during beta-receptor blockade

Torsade de pointes is a potentially lethal ventricular arrhythmia that is associated with prolonged QT intervals and is often caused by drugs that prolong repolarization. Among the most common drugs that may cause torsade de pointes are antiarrhythmic drugs including quinidine, procainamide, sotalol and newer class III antiarrhythmic agents. The incidence of torsade de pointes associated with amiodarone, however, is reported to be much lower. A case is reported of amiodarone-induced torsade de pointes following the development of the same arrhythmia during beta-blocker use. This case illustrates that although the reported incidence of torsade de pointes during amiodarone therapy is low, patients with bradycardia-induced torsade de pointes may be a subgroup of patients who are at increased risk of this arrhythmia with amiodarone.