Analysis of ambulatory electrocardiograms in 14 patients who experienced sudden cardiac death during monitoring.

The Holter monitors of 14 patients (out of 58,000 Holter recordings performed between 1978 and 1984) who experienced cardiac arrest and expired during the recording period were analyzed. Tachyarrhythmic arrest patients frequently had coronary heart disease, congestive heart failure, and prolonged QTc intervals. The highest incidence of intermediately frequent premature ventricular complexes (PVCs) occurred between 15 and 6 hours prior to death. The frequency of ventricular couplets increased toward the time of arrest. The hours with greatest frequency of ventricular tachycardia (VT) were found to be the last 5 hours of life. An increasing incidence of ST-segment changes greater than 2 mm was noted throughout all of the risk periods until the third hour prior to arrest when the incidence diminished. Conversely, the incidence of lower amplitude ST-segment changes (usually elevation) increased over the final 6 hours. The mean time of death was 0228 hours +/- 5:20. In conclusion, we observed two patterns of Holter-monitored changes which usually occurred prior to death and may represent predictors of sudden death: (1) an increasing incidence of intermediately frequent isolated PVCs followed by increased ventricular couplets and runs of VT; (2) return of high amplitude ST-segment changes toward baseline. To our knowledge, the temporal relationship of the degree of ST-segment deviation to sudden death and the time of sudden death have not been reported in large studies of Holter-monitored sudden death patients.