Prognostic significance of ventricular premature depolarizations measured 1 year after myocardial infraction in patient with early postinfarction asymptomatic ventricular arrhythmia

Abstract

Objectives. The objective of this study was to examine the relation between death and the frequency of premature ventricular depolarizations measured approximately 1 year after myocardial infarction.Background. The reported association between premature ventricular depolarizations and death in the weeks after myocardial infarction is in part the basis for the use of antiarrhythmic drugs. Such an association has not been reported on for observations obtained at a much greater interval after myocardial infarction.Methods. We examined the association between mortality and premature ventricular depolarization rates measured 1 year after myocardial infarction in patients with asymptomatic ventricular arrhythmia early (between 6 and 90 days, median 28) after infarction, as measured by 24-h ambulatory electrocardiographic recording. The study group consisted of 502 patients enrolled in the Cardiac Arrhythmia Pilot Study during 1983 to 1985. They were followed up during the course of the study and subsequently by a National Death Index search (average follow-up interval 1,080 days).Results. Death was recorded for 87 patients through 1987. Because patients were admitted to the Cardiac Arrhythmia Pilot Study only if they had ≥10 ventricular premature depolarizations/h, the arrhythmia rate measured at baseline (that is, early after infarction) was not expected to, and did not, predict mortality. In 360 patients ventricular premature depolarization rates were measured approximately 1 year from their index myocardial infarction while they were not receiving antiarrhythmic therapy. In these patients, who had survived 1 year after the index infarction, the rate of ventricular premature depolarizations/h measured 1 year after infarction was highly predictive of subsequent death (p < 0.001). Recent heart failure and a history of diabetes mellitus were also strongly predictive of death.Conclusion. The prognostic value of ventricular premature depolarizations observed 1 year after a myocardial infarction may be significant even in a sample selected for frequent ventricular premature depolarizations observed early after the event.