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Analysis of exercise-induced R wave amplitude changes in detection of coronary artery disease in asymptomatic men
Insights
Increased R wave amplitude during exercise is a sensitive indicator for detecting coronary artery disease in asymptomatic men with left bundle branch block, suggesting potential left ventricular dysfunction.
Area of Science:
- Cardiology
- Exercise Physiology
- Diagnostic Imaging
Background:
- Left bundle branch block (LBBB) can complicate electrocardiogram (ECG) interpretation.
- Asymptomatic individuals with LBBB require reliable methods for coronary artery disease (CAD) screening.
Purpose of the Study:
- To evaluate the utility of exercise-induced R wave amplitude changes in detecting CAD in asymptomatic men with acquired LBBB.
- To correlate R wave amplitude changes with angiographic findings and left ventricular function.
Main Methods:
- Analysis of exercise electrocardiograms (ECGs) in 44 asymptomatic men with acquired LBBB.
- Correlation of ECG findings with selective coronary angiography results.
- Assessment of left ventricular dysfunction using wall motion abnormalities and left ventricular end-diastolic pressure.
Main Results:
- An increase in R wave amplitude during exercise was observed in all 7 men with significant CAD (Group I) but only 10 of 37 men without CAD (Group II).
- This criterion demonstrated 100% sensitivity, 73% specificity, 41% predictive value, and 77% accuracy for CAD diagnosis.
- Greater increases in R wave amplitude correlated with left ventricular dysfunction.
Conclusions:
- Exercise-induced R wave amplitude increase is a highly sensitive marker for CAD in asymptomatic men with LBBB.
- This ECG finding may indicate underlying left ventricular dysfunction in this population.
Abstract:
The exercise electrocardiograms of 44 asymptomatic men with acquired left bundle branch block were analyzed for changes in R wave amplitude. Results were correlated with findings on selective coronary angiography. There were two subgroups: 7 men with significant angiographic coronary artery disease (Group I) and 37 with normal coronary angiograms (Group II). Exercise induced an increase in R wave amplitude in all seven men with coronary artery disease but in only 10 of the 37 men without significant coronary artery disease. This criterion thus had a sensitivity of 100 percent but a poor specificity of 73 percent, a predictive value of 41 percent and an accuracy rate of 77 percent for the diagnosis of coronary artery disease. The greater the increase in R wave amplitude the greater was the likelihood of some degree of left ventricular dysfunction as measured by wall motion abnormalities and elevated left ventricular end-diastolic pressure. The increase in R wave amplitude with exercise appears to be a sensitive test in identifying coronary artery disease in asymptomatic men with acquired left bundle branch block.