Seven cases of an unusual type of ventricular arrhythmia, already named "Torsades de pointe" by French authors, are presented. It is characterized by a changing pattern of the ventricular complexes, spontaneous onset and cessation, and refractoriness to defibrillation and antiarrhythmic drugs which decrease intraventricular conduction. Prior to its onset, Q-T prolongation is almost universally seen in the ECG. Hypokalemia, myocardial depressants and bradycardia are common causes. Isoproterenol and rapid cardiac pacing are recommended as the treatment of choice. This arrhythmia is a distinct entity, quite different from typical ventricular tachycardia or fibrillation.