Diagnostic Value Of Treadmill Exercise Test Combined With12-Lead Ambulatory Electrocardiography In Coronary Heart Disease

Objective:With coronary angiography (CAG) as the diagnostic criteria of coronary heart disease (CHD), explore the diagnostic value of treadmill exercise test (TET) combined with12-lead ambulatory electrocardiography (AECG) in coronary heart disease.Methods:112patients with suspected coronary heart disease underwent TET,12-lead AECG and CAG (Intervals of less than two weeks). All the patients were divided into CHD group and non-CHD group according to the result of CAG, which is the gold standard for the diagnosis of coronary heart disease.The basis for the division is that the luminal stenosis≥50%in at least one of the coronary arteries or its main branches in the left main coronary arteries (LM), left anterior descending arteries (LAD), left circumflex arteries (LCX) and right coronary arteries (RCA) of the patient in the group of CHD, otherwise he should be in the group of non-CHD. Patients in the CHD group were divided further into single-vessel lesion group and multi-vessels lesion group. Patients will be confirmed as single-vessel lesion with the CAG showing luminal stenosis of one vessel≥50%and multi-vessels lesion with two or more vessels in LAD, LCX and RCA. Multi-vessels lesion in the coronary arteries of the same side was regarded as main vessel lesion, lesion in the left main coronary arteries was divided into multi-vessels lesion group. Patients underwent standard treadmill tests to test patients’extreme exercise sub-extreme exercise according the Bruce Protocol with Marquette2000treadmill. Any results meeting with one of the following requirements can be regarded as treadmill test positive.(1)the ST segment (0.08s after J point) of lead which was centered with R wave moved down more or equal to0.1mv horizontally or decliningly based on the original level,and this moving kept more than two minutes during and after the exercise.(2) angina symptom or severe abnormal rhythm of the heart taken place during the process of exercise.(3) systolic pressure decreased10mmHg or more than10mmHg during the process of exercise. All the patients examined by12-lead ambulatory electrocardiography, the standard of which for the diagnosis of CHD were recommended by the ACC/AHA AECG Guideline in1999(1)the ST segment (0.08s after J point) of lead which was centered with R wave moved down more or equal to0.1mv horizontally or decliningly based on the original level;(2) displacement of ST segment lasts for at least1minute;(3) The interval of two attacks of transient ischemia is at least5minutes.(4) Establish ST elevation≥0.2mv as the standard for diagnosis of variable angina. Sensitivity and specificity of TET, AECG to the diagnosis of CHD were analyzed. Meanwhile, detection rate of TET and AECG for single-vessel lesion and multi-vessels lesion were also analyzed. Furthermore, sensitivity and specificity positive predictive value and negative predictive value of TET, AECG to CHD were tested and calculated by serial way of AECG&TET and parallel way of AECG&TET respectively.(In serial way result of diagnosis is viewed as positive only when all the results are positive; In parallel way, result of diagnosis is viewed as positive when one result is positive but negative only when the two results are negative.)Results:(1)The sensitivity was83.6%and the specificity was72.5%by means of TET. Positive rate94.1%in multi-vessles lesion were higher than single-vessle lesion70.4%. The sensitivity was77.0%and the specificity was82.4%by means of12-lead AECG. Positive rate88.2%in multi-vessels lesion group were higher than single-vessel lesion group63.0%.(2) In the result of12-lead AECG, the ST segment descent, duration, frequency and total ischemia burder in single-vessel lesion grorp and multi-vessels lesion group in ischemic attack were obviously different.(3) The specificity of CHD in the test by serial way of AECG&TET was96.1%and the positive predictive value was95.2%.The sensitivity of CHD in the test by parallel way of AECG&TET was95.1%and negative predictive value was90.9%.Conclusions:(1) Both TET and AECG have relatively high sensitivity and specificity for clinical diagnosis of coronary heart disease and positive rate of the diagnoses of CHD increases accordingly with the number of vessel lesion of coronary artery.(2) Accuracy of the diagnosis of CHD can be improved remarkably with the diagnoses of TET combined with AECG, namely, for those whose diagnostic results by TET and AECG are positive, the diagnostic value are high, false positive rates are low; for those whose diagnostic results by TET and AECG are both negative, diagnosis of coronary heart disease can be negated.