The value of ECG and echocardiography during stress testing for identifying systemic endothelial dysfunction and
1Albert Szent-Györgyi Medical University, Szeged, Hungary.
Insights
Stress-induced wall motion abnormalities predict coronary artery disease, while ST segment depression indicates endothelial dysfunction. Integrating ECG and functional markers improves stress testing accuracy for chest pain evaluation.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Vascular Biology
Background:
- Electrocardiogram (ECG) positivity is a common cause of false positives in stress testing.
- Abnormal endothelial function can occur in patients with chest pain despite normal coronary arteries.
Purpose of the Study:
- To assess how coronary anatomy and endothelial function influence stress test responses.
- To differentiate between epicardial and endothelial contributions to wall motion and ECG changes during stress.
Main Methods:
- Sixty-eight patients with chest pain underwent stress ECG echo, coronary angiography, and flow-mediated dilation testing.
- Positivity criteria included ST depression, wall motion abnormalities, coronary stenosis (>50%), and reduced flow-mediated dilation (<5%).
Main Results:
- Wall motion abnormalities predicted significant coronary artery disease (P=0.0003).
- ST segment depression predicted abnormal endothelial function (P=0.023), not coronary stenosis.
- No correlation was found between endothelial function and the severity of coronary artery disease.
Conclusions:
- Coronary anatomy impacts wall motion, while endothelial dysfunction affects ST depression during stress.
- ECG positivity is an unreliable predictor of coronary stenosis.
- Combining ECG and functional markers is essential for accurate stress testing.
Background:
In the stress imaging era, ECG positivity is regarded as a frequent source of false-positive responses. However, it is known that normal coronary arteries frequently coexist with abnormal endothelial function in patients with chest pain.
Aim:
To evaluate the anatomical coronary epicardial, and functional systemic endothelial determinants of wall motion and electrocardiographic responses during stress testing.
Method:
Sixty-eight in-hospital patients with chest pain syndrome, no previous myocardial infarction, and off nitrate therapy at the time of testing underwent, on different days, in random order and within 1 month: (1) stress ECG echo testing (with dipyridamole in 43, dobutamine in 3, and exercise in 22 patients); (2) coronary angiography; (3) endothelium-dependent, flow-mediated dilation of the brachial artery during reactive hyperaemia using high-resolution ultrasound. Criteria of positivity were: ST segment depression >0.1mm in the stress ECG; regional dysfunction >2 segments demonstrated by stress-echo; diameter reduction >50% on coronary angiography; and <5% flow-mediated dilation as revealed by endothelial function.
Results:
Significant coronary artery disease was present in 39 patients, and was predicted on multivariate analysis by stress-induced wall motion abnormalities (OR=108.8; 95% CI=8.5-1,389.4, P=0.0003), but not by either ST segment depression (P=0.13; OR=0.47; 95% CI=0.7-1.3) or reduced flow-mediated dilation (P=0.81; OR=0.87; 95% CI=0.27-2.8). Abnormal flow-mediated dilation was present in 53 patients (78%), and was predicted by stress-induced ST segment depression (P=0.023; OR=6.2; 95% CI=1.3-30.5), but not by either stress echo positivity (P=0.66; OR=0.77; 95% CI=0.23 to 2.5) or angiographically assessed coronary artery disease. There was no correlation between flow-mediated dilation and extent of coronary artery disease as assessed by the angiographic Duke score (from 0=normal to 100=most severe disease): r=-0.13, P=0.91.
Conclusion:
Epicardial coronary artery anatomy affects wall motion abnormalities, and systemic endothelial dysfunction affects ST segment depression during stress. However, echocardiographic positivity is unrelated to endothelial dysfunction, and electrocardiographic positivity is an inaccurate predictor of coronary stenosis. An integration of ECG and functional markers is warranted in the stress testing lab.
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