Outcome after abnormal exercise echocardiography for patients with good exercise capacity: Prognostic importance of the extent and severity of exercise-related left ventricular dysfunction

OBJECTIVES: We sought to define the prognostic implications of the extent and severity of exercise echocardiographic abnormalities in patients with good exercise capacity. BACKGROUND: The exercise capacity of patients with known or suspected coronary artery disease (CAD) is of prognostic importance, as is the extent of exercise-related left ventricular (LV) hypoperfusion or dysfunction. METHODS: We examined the outcomes of 1,874 patients with known or suspected CAD (mean age 64 ± 10 years, 64% men) who had good exercise capacity (≥5 metabolic equivalents [METs] for women, ≥7 METs for men) but abnormal exercise echocardiograms and analyzed the potential association between clinical, exercise and echocardiographic variables and subsequent cardiac events. RESULTS: Multivariate predictors of time to cardiac death or nonfatal myocardial infarction (MI) were diabetes mellitus (risk ratio [RR] 1.88; 95% confidence interval [CI] 1.2 to 3.0), history of MI (RR 2.44; 95% CI 1.6 to 3.6) and an increase or no change in LV end-systolic size in response to exercise (RR 1.61; 95% CI 1.1 to 2.5). Using echocardiographic variables that were of incremental prognostic value, we were able to stratify the cardiac risk of the study population; cardiac death or nonfatal MI rate per person-year of follow-up was 1.6% for patients who had a decrease in LV end-systolic size in response to exercise (n = 1,330) and 1.2% for patients who did not have any severely abnormal LV segments immediately after exercise (n = 868). CONCLUSIONS: In patients with good exercise capacity, echocardiographic descriptors of the extent and severity of exercise-related LV dysfunction were of independent and incremental prognostic value. Stratification of patients into low- and higher risk subgroups was possible using these exercise echocardiographic characteristics.