Clinical correlates and prognostic significance of exercise-induced ventricular premature beats in the community: the Framingham Heart Study.

Abstract

Recent investigations suggest that ventricular premature beats during exercise (EVPBs) are associated with increased cardiovascular mortality in asymptomatic individuals, but mechanisms underlying the association are unclear. We evaluated 2885 Framingham Offspring Study participants (1397 men; mean age, 43 years) who were free of cardiovascular disease and who underwent a routine exercise stress test; 792 participants (27%) had development of EVPBs (median, 0.22/min of exercise). Logistic regression was used to evaluate predictors of EVPBs. Cox models were used to examine the relations of infrequent (less than or equal to median) and frequent (greater than median) versus no EVPBs to incidence of hard coronary heart disease (CHD) event (recognized myocardial infarction, coronary insufficiency, or CHD death) and all-cause mortality, adjusting for vascular risk factors and exercise variables. Age and male sex were key correlates of EVPBs. During follow-up (mean, 15 years), 142 (113 men) had a first hard CHD event and 171 participants (109 men) died. EVPBs were not associated with hard CHD events but were associated with increased all-cause mortality rates (multivariable-adjusted hazards ratio, 1.86, 95% CI, 1.24 to 2.79 for infrequent, and 1.71, 95% CI, 1.18 to 2.49 for frequent EVPBs versus none). The relations of EVPBs to mortality risk were not influenced by VPB grade, presence of recovery VPBs, left ventricular dysfunction, or an ischemic ST-segment response. In our large, community-based sample of asymptomatic individuals, EVPBs were associated with increased risk of death at a much lower threshold than previously reported. Additional studies are needed to confirm these findings and to clarify the underlying mechanisms.