Usefulness of High Functional Capacity in Patients With Exercise-Induced ST-Depression to Predict a Negative Result on Exercise Echocardiography and Low Prognostic Risk

Although exercise electrocardiography (ExECG) is commonly used to detect coronary artery disease, the diagnostic accuracy and reliability of positive (ischemic) results of ExECG in low- and intermediate-risk populations are limited. Accordingly, many patients with positive results of ExECG undergo secondary evaluation using noninvasive stress imaging such as exercise echocardiography. Functional capacity is a strong predictor of prognosis and, indirectly, of high-risk coronary artery disease. It was hypothesized that high functional capacity in patients with positive results of ExECG would predict (1) negative results on subsequent exercise echocardiography and (2) a low risk for late mortality. Results were analyzed in 104 consecutive patients (79 men, 25 women; mean age 49 years, range 27 to 76) referred for exercise echocardiography after positive results of ExECG with a treadmill workload of ≥10 METs. Late all-cause mortality was also determined in these patients. Exercise echocardiographic results were negative in 93% of patients (97 of 104; 92% of men [73 of 79] and 100% of women [25 of 25]) and positive in 7% (7 of 104). During a mean follow-up period of 7.2 ± 1.9 years, there was 1 death. In conclusion, high functional capacity in patients with positive results of ExECG is associated with negative exercise echocardiographic results in most patients and very low late mortality. Patients with ischemic ST-segment response on ExECG who achieve workloads of ≥10 METs infrequently require additional noninvasive or invasive evaluation.