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Exercise-induced ST-segment variability may discriminate false positive tests
A P Michaelides1, G P Vyssoulis, A T Katsimichas
1Department of Cardiology, University of Athens Medical School, Hippokration Hospital, Greece.
Insights
Variations in ST-segment depression during exercise tests can help distinguish true coronary artery disease from false positives. This finding enhances the diagnostic accuracy of treadmill exercise testing for heart conditions.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Treadmill exercise tests are crucial for diagnosing coronary artery disease (CAD).
- Exercise-induced ST-segment depression and R wave amplitude variations are key ECG markers.
- Distinguishing true positive from false positive exercise tests remains a diagnostic challenge.
Purpose of the Study:
- To investigate the clinical value of exercise-induced variations in ST-segment depression and R wave amplitude.
- To determine if these variations can differentiate true positive from false positive exercise tests.
Main Methods:
- Studied 160 patients with positive treadmill exercise tests (Bruce protocol).
- Categorized patients into coronary artery disease (CAD) group (n=100) and normal coronary arteries group (n=60).
- Analyzed ST-segment depression and R wave amplitude variations in consecutive sinus beats, comparing coefficients of variation.
Main Results:
- Minimal ST-segment depression variation observed in 84% of CAD patients vs. 15% of normal artery patients (P < .0001).
- Significant ST-segment depression variation observed in 16% of CAD patients vs. 85% of normal artery patients (P < .0001).
- Coefficient of variation for ST-segment depression was significantly greater in normal artery patients than in CAD patients (P < .0001).
Conclusions:
- Variability of ST-segment depression at peak exercise can discriminate false positive from true positive exercise tests.
- This analysis improves the diagnostic ability of treadmill exercise testing for coronary artery disease.
Abstract:
The clinical value of exercise-induced variations in ST-segment depression and R wave amplitude in consecutive sinus beats was studied in 160 patients who had a positive treadmill exercise test with the Bruce protocol. The patients, all of whom underwent cardiac catheterization, included 100 with coronary artery disease (CAD) (group with true positive test) and 60 with normal coronary arteries (group with false positive test). Minimal or no exercise-induced variations in the magnitude of ST-segment depression despite variations in R wave amplitude were observed in 84 of the 100 patients with CAD and in only 9 of the 60 patients with normal coronary arteries (P < .0001). Significant exercise-induced variations in ST-segment depression were observed in only 16 of 100 patients with CAD and in 51 of 60 patients with normal coronary arteries (P < .0001). The coefficient of variation of R wave amplitude was similar in both groups (no statistical significance), while the coefficient of variation of ST-segment depression was much greater in the patients with normal coronary arteries than in those with CAD (P < .0001). It is concluded that variability of ST-segment depression at peak exercise may discriminate false positive from the true positive exercise tests, improving the diagnostic ability of the method.