[Iatrogenic torsade de pointes induced by thioridazine].

Torsade de pointes is a form of polymorphous ventricular tachycardia in which the polarity of the QRS complex exhibits phasic alterations in both axis. Traditionally, torsade de pointes has been described in association with a congenital or acquired (including drug and metabolic) causes of QT prolongation. Clinical outcomes range from asymptomatic, self-terminating arrhythmias to ventricular fibrillation resulting in cardiac arrest. For the treatment of torsade de pointes, the conventional antiarrhythmic drugs cannot be relied on, cardiac pacing should be instituted as soon as possible; however, as this technique may not always be immediately available, isoproterenol infusion may be the first-choice treatment. Potassium and magnesium repletion appear to be essential in abolishing drug-induced torsade de pointes. This report describes a case of thioridazine-induced torsade de pointes treated efficaciously with magnesium sulphate and overdrive right ventricular pacing.