The diagnostic utility of the basal and post‐exercise QRS‐T angle in patients with stable coronary artery disease

BACKGROUND: To evaluate the diagnostic utility of basal and post‐exercise QRS‐T angle in patients with stable coronary artery disease (CAD). METHODS: This cross‐sectional and observational study analyzed 190 patients with stable angina. The QRS‐T angle is measured on the 12‐lead electrocardiograms at baseline and just after stopping the treadmill stress test in patients undergoing conventional coronary angiography (CAG). The pre‐ and post‐exercise QRS‐T angle and ΔQRS‐T angle were analyzed. RESULTS: Of the 190 patients, 66 (34.7%) were assigned to group 1 (patients with coronary lesion) and 124 (65.3%) to group 2 (patients without coronary lesion) after CAG. There was no statistically significant difference in QRS‐T angle between groups at baseline (pre‐exercise) (30.7 ± 17 vs. 27.8 ± 12.8, p = .233). The QRS‐T angle value was significantly higher in group 1 than in group 2 (68.8 ± 40.3 vs. 22.7 ± 21.5, p = .01) after exercise (post‐exercise). The ΔQRS‐T angle was also significantly higher in group 1 than in group 2 (38.1 ± 37.6 vs. −5.1 ± 22.9, p = .01). Receiver operating characteristic curve revealed that the cut‐off value of QRS‐T angle (post‐exercise) for the coronary obstruction was >51.5° with 81% of sensitivity and 66% of specificity (AUC: 0.832, p = .001, CI: 0.769–0.894). Duke treadmill score for coronary stenosis was >1.5 with 77% of sensitivity and 69% of specificity (AUC: 0.814, p = .001, CI: 0.749–0.878). CONCLUSION: It could be proposed that post‐exercise QRS‐T angle and Δ QRS‐T angle are significantly associated with coronary obstruction in patients with stable angina and appear to be more sensitive than the Duke treadmill score and traditional electrocardiographic parameters.