Background: Clinical meaning of recovery phase limited ST segment depression of a treadmill exercise test is controversial. The aim of this study was to re-assess the diagnostic and prognostic value of ST segment depression during the recovery phase with the active phase of a treadmill exercise test in suspected coronary artery disease patients.
Methods: Clinical, exercise and angiographic data were retrospectively collected from 602 patients in the study. Five hundred and seventy-six patients developed ST segment depression during the active phase of the treadmill exercise test (group 1) and 26 patients developed ST segment depression only during the recovery phase (group 2).
Results: With similar major clinical features, the prevalence of significant coronary artery stenosis and average Gensini scores were lower in the recovery phase-limited depression patients (group 2 vs. group 1, 50.0% vs. 66.9%, P = 0.031 and group 2 vs. group 1, 1.5 vs. 8.5, P = 0.04). At a median follow up of 50.9 months for 22 group 2 and 34.8 months for 438 group 1 patients, the prevalence of total cardiac events was higher in group 1 than in group 2 patients (RR 1.60, 95% CI 1.00-2.54, P = 0.049).
Conclusion: The present study provides preliminary evidence that the diagnostic and prognostic value of recovery phaselimited ST segment depression of treadmill exercise test is limited.