Frequency and Influence of Exercise-Induced Artifact in Electrocardiograms During Exercise Treadmill Testing for Detection of Myocardial Ischemia.

Abstract

Exercise treadmill testing (ETT) is frequently utilized for noninvasive detection of myocardial ischemia and coronary artery disease. The frequency of electrocardiogram (ECG) artifacts (ECGA) during ETT and their influence on the identification of exercise-induced ischemia are not known. We reviewed all ETTs with ST segment depression in the University of California, Davis, Medical Center treadmill database during each of the years 2012 and 2016 to identify tests with exercise-induced ST segment depression in the inferior and inferolateral leads. We identified cases with ECGA during progressive phases of the test, and we assessed the influence of comorbidities and the impact of ECGA on the diagnosis of coronary artery disease. Tests were considered false or true positive based on the result of confirmatory tests. Of 2,100 tests, we identified 123 patients with exercise-induced ST segment depression in inferior or inferolateral leads (men, 43%; mean age, 59 ± 10 years; white, 59%). Tests were symptom-limited: maximum heart rate, 153 ± 18; peak METs (metabolic equivalents of resting total oxygen consumption), 9.4 ± 2.7; ECGA occurred in 91% of tests at peak exercise with earlier occurrence among females. Tests were less likely to be true positive with peak ECGA than those without ECGA (13% vs. 50%, p = 0.05). ECGA at peak exercise are frequent and related to peak heart rate and peak metabolic equivalents of resting total oxygen consumption, suggesting a motion effect. ECGA affected the diagnostic accuracy of ETT examinations, indicating that algorithms to reduce artifact for improved diagnosis of ETT require further investigation.