Torsade de pointes: a mechanism for sudden death associated with neuroleptic drug therapy?

An elderly institutionalized woman developed the ventricular arrhythmia torsade de pointes while receiving lithium and thioridazine, 800 mg daily. On hospital admission following a single syncopal episode the electrocardiogram showed sinus bradycardia with first degree AV block, markedly prolonged QT interval, and prominent U waves. Following discontinuation of thioridazine and lithium, episodes of recurrent torsade de pointes gradually subsided. Seven days later the electrocardiogram showed normal sinus rhythm with PR interval of 0.20 seconds and minimal U waves, and the arrhythmia has not recurred.