Usefulness of Excellent Functional Capacity in Men and Women With Ischemic Exercise Electrocardiography to Predict a Negative Stress Imaging Test and Very Low Late Mortality

Abstract

Exercise electrocardiography (ExECG) is widely employed to assess patients for coronary artery disease but it has limited diagnostic accuracy. Many patients with positive (ischemic) tests based on exercise-induced ST depression undergo secondary evaluation by noninvasive stress imaging. We hypothesized that high functional capacity in patients with positive ExECG could predict: (1) negative results in secondary evaluation by exercise echocardiography (ESE) or myocardial perfusion scintigraphy (MPS) and (2) low mortality on late follow-up. We evaluated 511 consecutive patients (312 men, 199 women; age 51 ± 9 years) referred for ESE or MPS after an ischemic ExECG at a treadmill workload of ≥10 metabolic equivalents. All-cause mortality was also obtained. Of 511 patients, 401 underwent ESE and 110 had MPS for secondary study. ESE was negative in 94% (376 of 401) and positive in 6% (25 of 401). MPS was also negative in 94% (103 of 110) and positive in 6% (7 of 110). Total stress imaging results were negative in 92% (286 of 312) of men and 97% (193 of 199) of women. During follow-up of approximately 6 years, there were 3 deaths with total all-cause mortality of 0.6% and average annual mortality of 0.1%. In conclusion, high functional capacity in patients with an ischemic ExECG predicts a negative ESE or MPS in a large majority of patients and very favorable late survival in both men and women. These results suggest that patients with ischemic ExECGs and a workload of ≥10 metabolic equivalents during ExECG may not require additional noninvasive or invasive evaluation.