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.