Characterization of ventricular tachyarrhythmias on ambulatory ECG recordings in post-myocardial infarction patients: Arrhythmia detection and duration of recording, relationship between arrhythmia frequency and complexity, and day-to-day reproducibility

Abstract

We performed three consecutive 24-hour ECG recordings in 57 ambulatory patients approximately 8 to 11 days of post-myocardial infarction. There was considerable additional detection of each type of complex ventricular ectopic beat (VEB) with recordings beyond 24 hours. Multiform, R-on-T, pairs, and bigeminy were often first detected from 24 to 48 hours and 5 of 12 patients with ventricular tachycardia had this rhythm detected only after 48 hours of monitoring. Complex forms were deleted with short recording durations primarily in patients who had complex forms present during a large number of hours during the 72-hour recording session. The occurrence of each type of complex ectopic beat was strongly related to PVC frequency and some type of complex form was seen in virtually all 24-hour recordings with greater than a total of 100 VEBs. Sixty-five percent of 24-hour recordings with infrequent VEBs (2 to 10 per 24 hours) also had complex forms present. The day-to-day reproducibility of VEB frequency and complexity was reasonable, but was largely accounted for by the fact that most recordings were free of frequent ectopic beats and a given type of complex PVC. These data suggest that for longer ECG recording period, the frequency of occurrence of complex forms rather than simply their presence or absence may be important for identifying high risk subgroups.