Ventricular tachycardia with torsade de pointes morphology induced by oral disopyramide.

The oral administration of disopyramide for the maintenance of sinus rhythm after cardioversion from atrial fibrillation resulted in prolongation of the Q-T interval and three episodes of ventricular tachycardia with the torsade de pointes morphology. This morphology is characteristic of the arrhythmias of quinidine 'syncope'. Its appearance with disopyramide is not unexpected in view of the quinidine-like effects of the latter and suggests that it should be prescribed with the same caution as quinidine.