This study investigated whether significant coronary artery stenosis in 231 consecutive unstable angina patients can be diagnosed by thoroughgoing history-taking initial electorocardiography and symptom- or sign-limited treadmill exercise ECG after medication. The unstable angina patients were divided into those with accelerated angina, those with new-onset effort angina and those with angina at rest based on the findings of detailed inquiry. Initial ECG showed that the sensitivity and specificity of detecting significant coronary artery stenosis in all patients were 55.2% and 63.2%, respectively. In accelerated angina, sensitivity and specificity were 52.2% and 50.0%, respectively. In new-onset effort angina, sensitivity and specificity were 46.7% and 57.1%, respectively. In angina at rest, sensitivity and specificity were 69.0% and 68.3%, respectively. Initial ECG provided valuable diagnostic information about angina at rest. Treadmill exercise ECG offered 66.0% sensitivity and 89.2% specificity in all patients, respectively. In accelerated angina, sensitivity and specificity were 80.0% and 66.7%, respectively. In new-onset effort angina, sensitivity and specificity were 70.8% and 87.8%, respectively. In angina at rest, sensitivity and specificity were 48.3% and 91.4%, respectively. Thus, treadmill exercise electrocardiograms provided valuable diagnostic information in the case of unstable angina, especially accelerated angina and new-onset effort angina. For patients with angina at rest, this testing was very useful for excluding significant coronary artery stenosis.
In conclusion, detailed inquiry, initial ECG and symptom- or sign-limited treadmill exercise ECG after medical stabilization proved to be of great value for diagnosing unstable angina patients with significant coronary artery stenosis.