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The localization of coronary artery stenoses by 12 lead ECG response to graded exercise test: support for
Insights
Coronary artery stenoses location and severity correlate with ischemic ST changes on postexercise electrocardiograms (ECGs). However, intercoronary collateral channels can alter these findings, limiting ECG prediction accuracy in coronary artery disease.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Exercise Physiology
Background:
- The 12-lead electrocardiogram (ECG) is crucial for diagnosing coronary artery disease (CAD).
- Postexercise ECG changes can indicate myocardial ischemia.
- Predicting the precise location and severity of coronary artery stenoses from ECG findings remains a challenge.
Purpose of the Study:
- To correlate the location and severity of coronary artery stenoses with specific ECG leads showing ischemic ST changes.
- To investigate the influence of collateral circulation on postexercise ECG findings in patients with CAD.
Main Methods:
- Correlating coronary artery stenoses (location, severity) with ischemic ST changes in 39 patients with positive postexercise ECGs.
- Analyzing ECG lead patterns associated with right vs. left coronary artery stenoses.
- Evaluating 11 patients with atypical ST changes for collateral channel presence.
Main Results:
- Right coronary artery stenoses correlated with ST changes in Leads II, III, and aVF.
- Left coronary artery stenoses correlated with ST changes in Leads I, aVL, and chest leads.
- 11 patients with atypical ST changes had significant collateral channels, supporting intercoronary steal during exercise.
Conclusions:
- While coronary artery stenoses location influences postexercise ECG changes, collateral circulation can modify these patterns.
- The presence of collateral channels can reduce the accuracy of the postexercise 12-lead ECG in predicting the location and severity of coronary artery stenoses.
- Intercoronary "steal" phenomenon during exercise may explain atypical ECG findings in CAD.
Abstract:
In 39 consecutive patients with unequivocally positive postexercise ECG we have correlated the location and severity of the coronary artery stenoses with the ECG leads in which ischemic ST changes occured. Patients with major stenoses of the right coronary artery, with or without disease of the left coronary system, showed ischemic ST changes in Leads II, III, and aVF. Patients with major stenoses of the left coronary system, many of whom had suffered old inferior wall infarction, showed ST changes in Leads I, aVL, and the chest leads. A group of 11 patients showed ischemic ST changes in leads other than those expected on the basis of the location and severity of coronary artery stenoses. In each of these 11 patients large collateral channels were donated by the vessel in whose territory the ischemic changes occurred. This finding lends support to the concept of intercoronary "steal" during exercise in coronary artery disease, at the same time reducing the value of the postexercise 12 lead ECG in predicting the location and severity of coronary artery stenoses.