Sudden death during ambulatory monitoring.

Three patients with ischaemic heart disease died suddenly while being monitored with an ambulatory tape recorder. Two had terminal ventricular fibrillation initiated by paired bidirectional ventricular ectopic beats against a background of scattered ectopic activity; both had had ventricular tachycardia during routine treadmill exercise testing in the week before death. The third patient developed bizarre ventricular complexes followed by asystole. Sudden death may be due to ventricular fibrillation initiated by paired ventricular ectopic beats with changing morphology, or asystole following bizarre ventricular complexes. Exercise testing may have an important predictive value.