Frequency and complexity of ventricular ectopic beats in the posthospital phase of myocardial infarction.

This study is a descriptive report of the occurrence of ventricular arrhythmias in a large, prospectively designed follow-up study of postcoronary patients. Six-hour Holter recordings were obtained on 954 postinfarction patients prior to hospital discharge and at 4 (n = 837), 8 (n = 762), 12 (n = 713), and 24 (n = 487) months post-discharge. Ventricular ectopic beats (VEB) were quantitated by frequency and patterns at each recording, and antiarrhythmic medication usage was recorded. The proportion of patients wtih each VEB frequency (any, less than 9.9/hour, 10 - 19.9/hour, greater than or equal to 20/hour) increased progressively during the 24-month follow-up, with the most significant increase in the interval between baseline and the four-month follow-up recording. Significant (p less than 0.01) associations were found between VEB frequency greater than or equal to 20/hour and almost all VEB patterns for each follow-up; no significant associations were found between VEB prematurity (RR'/QT less than or equal to 1.00) and any of the VEB patterns. Among the survivors, the utilization of diuretics and beta blockers increased (p less than 0.01) and antiarrhythmic agents declined (p less than 0.01) between predischarge and all subsequent follow-up visits. The significance of these findings is discussed.