Exercise electrocardiography and myocardial perfusion imaging in the diagnosis of coronary artery disease: preliminary report.

Exercise electrocardiography and rest/exercise myocardial perfusion imaging with thallium-201 were performed in 43 patients with typical angina or atypical chest pain; the results were correlated with those of coronary arteriography. Exercise electrocardiography sensitivity was 65%, specificity was 78%, predictive value for a positive result was 73% and for a negative result was 93%. The low sensitivity of the exercise electrocardiogram was mainly due to the number (13 of 43, 30%) of inconclusive results (no ST-segment change on the electrocardiogram, but failure to attain the target rate), most of which were in the group with typical angina. The predictive value of exercise electrocardiography for both a positive and negative result was excellent in typical angina. In patients with atypical chest pain, the negative predictive value was high (90%) but the positive predictive value was very low (50%). The sensitivity of myocardial perfusion imaging was 71%, specificity was 59%, positive predictive value was 52% and negative predictive value 89%. The low specificity of this test is related to the number of false-positive results obtained, most of which occurred in the group with atypical pain. When the results of exercise electrocardiography and myocardial perfusion imaging are combined, the sensitivity is increased but specificity is unacceptably low. However, myocardial perfusion imaging in patients with an inconclusive result from exercise electrocardiography (most of them in the group with typical angina) showed a sensitivity of 80%, specificity of 88%, positive predictive value of 80% and negative predictive value of 100%.