Sudden death recorded during Holter monitoring.

Six instances of sudden death were recorded by Holter monitoring, which showed ventricular fibrillation in five and a bradyarrhythmia in one. Complex ventricular ectopic activity preceded cardiac arrest in five patients, including the one with the bradyarrhythmic arrest. Two patients with chronic bifascicular block arrested as a result of ventricular fibrillation. Fifteen cases reports from the literature are reviewed. The composite profile includes advanced myocardial disease (present in all cases), complex ventricular ectopic activity, R-on-T initiation of the terminal rhythm except in patients with prolonged QT interval, and variations in cycle length preceeding the onset of ventricular tachycardia or fibrillation. The role of supraventricular mechanisms in sudden death is uncertain.