The Long-Term Prognostic Significance of High-Grade Ventricular Ectopic Activity in Survivors of Acute Myocardial Infarction

Abstract

Previous studies have shown increased mortality related to ventricular ectopic activity in survivors from acute myocardial infarction. This report focuses on the 10-year prognostic significance of ventricular ectopic activity among 1,737 patients with acute myocardial infarction who underwent 24-hour Holter monitoring between 7 and 21 (mean 12) days after the infarction. Among this group of patients, 573 (33%) were free from ventricular ectopic activity, 670 (39%) had Lown grade 1-2 and 455 (26%) Lown grade 3-4 premature ventricular contractions. Thirty-nine patients (2%) exhibited ventricular tachycardia. The distribution of ventricular ectopic activity was similar among men and women, but increased significantly with age, previous history of myocardial infarction, and higher Killip class, as well as among patients with very high enzyme levels. Multivariate analysis adjusted for clinical and Holter variables showed that ventricular tachycardia was an independent predictor for 1-year mortality (relative risk 2.70; 90% confidence interval 1.19-6.19) but its effect diminished to some extent 10 years later (relative risk 1.39; 90% confidence interval 0.94-2.06). Frequent premature ventricular contractions (Lown grade 3-4) were associated with somewhat increased risk for 10-year mortality (relative risk 1.21, 90% confidence interval 1.04-1.41). Although the mechanisms by which ventricular ectopic activity increases subsequent mortality have not been completely elucidated, the results of this study suggest that ectopic ventricular activity is an independent contributor to the excess mortality observed in these patients.