"Recovery Only" ST-Segment Depression and the Predictive Accuracy of the Exercise Test

Abstract

STUDY OBJECTIVE: To clarify the predictive value of exercise-induced ST-segment depression occurring in recovery only, and to determine whether the addition of recovery data improves the interpretation of the exercise test. DESIGN: Retrospective analysis of data collected during exercise testing and coronary angiography. SETTING: A 1000-bed Veterans Affairs Medical Center. PARTICIPANTS: The study included 328 male patients who had had both a sign- or symptom-limited treadmill test and coronary angiography. MEASUREMENTS AND MAIN RESULTS: Of the 168 patients who had abnormal ST-segment responses, 26 had such responses only during recovery. The positive predictive value of this pattern for significant angiographic disease (84%) was not statistically different from the predictive value of ST depression occurring during exercise (87%). Inclusion of ST depression during recovery significantly increased the sensitivity of the exercise test from 50% to 59% (P = 0.01) without a change in predictive value. In addition, ST-segment depression occurring only during exercise is usually associated with less-severe angiographic coronary artery disease. CONCLUSION: The occurrence of ST-segment depression during the recovery period only, does not generally represent a "false-positive" response. The inclusion of findings from this period increases the diagnostic yield of the exercise test. Previously proposed exercise test scores, as well as exercise electrocardiography (ECG) analysis done in conjunction with scintigraphy, have a falsely lowered sensitivity that could be increased by considering ST-segment changes occurring in recovery.