Useless diagnostic value of exercise-induced R wave changes in coronary artery disease
Insights
Exercise-induced R wave amplitude changes are not useful for diagnosing coronary artery disease or detecting left ventricular contraction abnormalities. ST segment depression during exercise is a more sensitive indicator for coronary artery disease diagnosis.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Coronary artery disease (CAD) diagnosis often relies on exercise stress testing.
- Evaluating R wave amplitude changes during exercise is a potential, yet unproven, diagnostic marker.
Purpose of the Study:
- To assess the diagnostic utility of exercise-induced R wave amplitude changes.
- To determine the effectiveness of R wave changes in detecting left ventricular contraction abnormalities in patients with CAD.
Main Methods:
- Studied 105 patients undergoing exercise stress tests.
- Analyzed R wave amplitude changes and ST segment depression in relation to coronary artery stenosis.
- Correlated R wave changes with left ventricular contraction abnormalities.
Main Results:
- R wave amplitude changes showed low sensitivity (67%) and specificity (27%) for diagnosing significant coronary artery disease compared to ST segment depression (86% sensitivity, 88% specificity).
- For left ventricular contraction abnormalities, R wave changes yielded 80% sensitivity but only 41% specificity.
- No significant differences in exercise intensity or ejection fraction were found between groups with differing R wave amplitude changes.
Conclusions:
- Exercise-induced R wave amplitude changes are not a reliable indicator for diagnosing coronary artery disease.
- R wave amplitude changes are not effective in detecting left ventricular contraction abnormalities.
- ST segment depression remains a more valuable marker in exercise stress testing for CAD evaluation.
Abstract:
To investigate the usefulness of exercise-induced R wave changes in the diagnosis of coronary artery disease and detection of left ventricular contraction abnormalities, 105 patients were studied. Among 64 patients who had significant coronary artery disease (greater than or equal to 70% narrowing), 43 showed an increase or no change in the R wave amplitude and 55 showed ST segment depression (sensitivity 67 versus 86%). Among 41 patients without significant stenosis, 11 had decreased R wave amplitude and 36 had no change in ST segment (specificity 27 versus 88%). Twenty-five of 64 coronary disease patients had left ventricular contraction abnormalities, and the R wave amplitude changes gave a sensitivity of 80%, specificity of 41% and a predictive value of 47%. There were no differences in the variables of exercise intensity and ejection fraction between patients who had decreased R wave amplitude and those in whom it increased or did not change. We conclude that R wave amplitude change during exercise is not a useful variable for the diagnosis or evaluation of patients with coronary artery disease.
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