Useless diagnostic value of exercise-induced R wave changes in coronary artery disease

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.