Abstract
BACKGROUND: Exercise electrocardiography in asymptomatic adults has been criticized because of relatively poor accuracy predicting future heart disease risk, but studies may have been too short. We investigated if integrated analysis of graded exercise tolerance tests (GXT) predicted long-term coronary heart disease (CHD) and all-cause mortalities among community-dwelling older adults. METHODS AND RESULTS: From 1972 to 1974, 1789 adult residents of a predominantly Caucasian, middle- to upper-middle-class southern California community participated in a clinical evaluation that included a GXT; 52.4% (N=939) of those who had baseline GXT were followed up to 2010-up to 36years-for vital status, CHD and all-cause mortality. Multiply adjusted hazard ratios of an abnormal graded GXT were 1.65 (95% CI 0.78-3.49) and 1.56 (95% CI 1.15-2.11) for CHD and all-cause mortality, respectively. An integrated analysis hazard ratio was calculated based on the following GXT findings: significant ST change, inability to achieve target heart rate [THR], abnormal heart rate recovery [HRR], and chronotropic incompetency [ChI]. Compared to those with 0 or 1 abnormality, participants with 2 or more positive findings had significantly higher CHD (HR 2.18) and all-cause (HR 1.92) mortalities. Participants with 3 or more positive findings showed even higher hazard ratios-CHD (HR 6.16) and all-cause (HR 2.49) mortalities. When adjusted for any of 3 Framingham risk models, the integrated electrocardiographic model correlated well with CHD and all-cause mortalities. CONCLUSIONS: An integrated analysis of electrocardiographic and non-electrocardiographic measures of GXT is useful in predicting long-term CHD and all-cause mortalities in an asymptomatic middle-aged population.