Negative Exercise Electrocardiogram Research Articles

Early exercise testing and elective coronary artery bypass surgery after uncomplicated myocardial infarction. Effect on morbidity and mortality.

One hundred and nineteen consecutive patients were studied prospectively after uncomplicated myocardial infarction by maximal exercise electrocardiography at two weeks and coronary angiography at six weeks. At angiography 87 patients had a stenosis greater than 70% in one major coronary artery supplying residual viable myocardium outside the infarction zone. In 82 (94%) of these the 12 lead maximal exercise electrocardiogram correctly identified these areas of ischaemic but viable myocardium. Based on ST criteria alone five patients had a false negative exercise electrocardiogram for additional disease. Nevertheless, three developed angina or a significant fall in systolic blood pressure or both at a low workload. On the basis of the anatomical lesions, symptoms, and the results of the European Coronary Surgery Study Group 55 patients were allocated for surgery. Of these, 54 underwent coronary artery bypass grafting within three months of myocardial infarction. One patient died perioperatively and another died after a reinfarction at four months while awaiting surgery. The remaining 53 were symptom free during a mean follow up period of 37 months. Sixty four patients received medical treatment. At angiography 32, 24, and eight patients had one, two, and three vessel coronary disease respectively. The exercise electrocardiogram correctly predicted the anatomy in 60 (94%), with two false positive and two false negative results for additional disease. The eight patients with three vessel disease treated medically had generalised inoperable disease, and at follow up three had died after a further infarction and five remained symptomatic with full medical treatment. Thus of those designated as at high risk and considered suitable for surgery the 37 month survival was 53 or 54 patients treated surgicall7y.

Can exercise electrocardiography and thallium-201 myocardial imaging exclude the diagnosis of coronary artery disease?: Bayesian analysis of the clinical limits of exclusion and indications for coronary angiography

The objective of this study was to determine whether exercise electrocardiography can be combined with thallium-201 myocardial imaging and the clinical history to exclude the diagnosis of coronary artery disease. All 96 patients in this study were referred for coronary angiography because of chest pain but did not have prior myocardial infarction; 52 percent had coronary artery disease. Each patient's chest pain was classified as either typical or not typical of angina pectoris. Negative tests with inadequate exercise stress (less than 85 percent of the age-predicted maximal heart rate) and combined tests with discordant results (either exercise electrocardiography or thallium imaging positive and the other test negative) were judged nondiagnostic. Nondiagnostic tests that contributed most to the uncertainty of results were classified separately: exercise electrocardiogram, 35 patients; thallium imaging, 9 patients; and combined exercise electrocardiogram and thallium imaging, 50 patients. The ability of each test to rule out coronary artery disease was defined by its predictive error (probability of coronary disease despite a negative test): history of chest pain not typical of angina, 26 percent (11 of 42); exercise electrocardiogram, 22 percent (5 of 23); thallium imaging, 27 percent (6 of 35); and negative findings on both exercise electrocardiogram and thallium imaging, 6 percent (1 of 17). Finally, when only the patients with atypical chest pain were considered, there was zero (0 of 15) predictive error if both tests were negative. Negative exercise electrocardiography and thallium imaging during adequate stress ruled out any coronary artery disease in these patients with considerable reliability (94 percent) and excluded multivessel disease with even greater reliability. These exclusion tests for coronary artery disease were most reliable in patients in whom the clinical diagnosis of coronary artery disease was least likely, as defined by Bayes' theorem. It is concluded that there is no perfect noninvasive test to exclude coronary disease in all patient populations; however, coronary angiography is not necessary to rule out the diagnosis of coronary artery disease in patients who'have (1) no clinical indicators of a very high probability of coronary disease, such as typical angina, (2) adequate exercise stress, (3) negative exercise electrocardiogram and (4) negative exercise thallium images.

Importance of coronary collateral circulation in interpreting exercise test results

The Importance of the coronary collateral circulation as a cause of false negative exercise tests was studied in 37 patients who had a 90 percent or greater isolated stenosis of the luminal diameter in one major coronary artery. Sixteen patients had large collateral vessels and 21 patients had either minimal or no collateral circulation. Myocardial scintigraphy was performed in 22 of the 37 patients. The final treadmill time was similar in both groups (521 ± 192 versus 554 ± 144 seconds [mean ± standard error of the mean]). The presence and depth of S-T segment depression was not influenced by the degree of collateralization. The sensitivity of the exercise electrocardiogram was greater for patients with disease in the left anterior descending than in the right or left circumflex coronary arteries (95 versus 60 percent, p <0.03). Among the 22 patients with thallium-201 scintigrams, myocardial perfusion defects were more common in patients without collateral circulation (100 versus 40 percent, p <0.01) and Involved more myocardial segments (p <0.005). The overall sensitivity of exercise electrocardiography for the detection of single vessel stenosis 90 percent or greater was similar to that of myocardial scintigraphy (81 versus 73 percent). In conclusion, large intercoronary collateral vessels are not a cause of false negative exercise electrocardiograms in patients with single vessel disease but are a common cause of false negative scintigrams. Large collateral vessels may limit the quantity and location of myocardial ischemia, but exercise etectrocardtography and thallium-201 scintigraphy may detect different aspects of ischemia.

Value of Treadmill Exercise Testing in Patients With Complete Bundle Branch Block

Exercise electrocardiography and selective coronary arteriography was performed in 24 consecutive patients with complete bundle branch block. The criteria for a positive exercise electrocardiogram (E-ECG) were a 1 mm depression or elevation in the J point from the control state, as well as in the ST-segment measured at 0.04 seconds from the J point. Eleven of 12 patients with complete left bundle branch block had a positive E-ECG. Nine of them had normal coronary arteriograms, except one with less than 50% lesions in two arteries. Two patients had severe three-vessel disease. Only one patient had a true negative exercise test. No patient had a false negative test. Nine of 12 patients with complete right bundle branch block had a positive E-ECG. One of these 9 had minimal nonobstructive disease, while the other 8 had severe two- or three-vessel coronary artery disease. Three of the 12 right bundle branch block patients had a negative E-ECG. Two of them had a true negative exercise test, and one a false negative test. Because of a high incidence of probably false positive results, E-ECG appears to be unreliable in detecting coronary artery disease in patients with complete left bundle branch block. But it can provide useful information in the noninvasive evaluation of coronary artery disease in patients with complete right bundle branch block.

Coronary arteriography: Correlation with electrocardiographic response to measured exercise

Measured exercise rarely produced specific S-T segment deviations when the coronaryarteries were free of discernible atherosclerosis, provided other conditions capable of interfering with the balance between coronary flow and the metabolic needs of the myocardium were not present. However, negative exercise electrocardiograms were also recorded in patients with angina pectoris and both nonobstructive and obstructive coronary atherosclerosis as visualized by arteriography. The incidence of negative responses was influenced by the inclusion of patients with past transmural infarctions.Abnormal exercise electrocardiograms were obtained mainly when patients with angina pectoris had demonstrable nonobstructive and obstructive coronary artery disease. However, specific S-T segment alterations were also encountered when the coronary arteriography was normal if a structural or functional defect was present capable of altering the balance between coronary flow and myocardial need.

Coronary arteriography: Correlation with electrocardiographic response to measured exercise

Abstract Measured exercise rarely produced specific S-T segment deviations when the coronaryarteries were free of discernible atherosclerosis, provided other conditions capable of interfering with the balance between coronary flow and the metabolic needs of the myocardium were not present. However, negative exercise electrocardiograms were also recorded in patients with angina pectoris and both nonobstructive and obstructive coronary atherosclerosis as visualized by arteriography. The incidence of negative responses was influenced by the inclusion of patients with past transmural infarctions. Abnormal exercise electrocardiograms were obtained mainly when patients with angina pectoris had demonstrable nonobstructive and obstructive coronary artery disease. However, specific S-T segment alterations were also encountered when the coronary arteriography was normal if a structural or functional defect was present capable of altering the balance between coronary flow and myocardial need.