[en] Exercise thallium myocardial scintigrams were analyzed in 76 consecutive patients with documented normal coronary arteries to identify the factors associated with abnormal or ''false positive'' studies. The thallium scintigrams had been judged normal in 60 patients (79 percent) and abnormal in 16 (21 percent). Analysis of the location of thallium defects in the 16 patients with abnormal scintigrams revealed a pattern that was consistent with coronary artery disease in 5, including 4 with an abnormal left ventricle, and a pattern that was inconsistent in the other 11. In 9 of these 11 patients the pattern of defects suggested soft tissue attenuation, by the diaphragm in 2 and breast or adipose tissue in 7, whereas in the other 2 patients isolated apical defects were seen. Among exercise myocardial scintigrams performed in 68 randomly selected patients with abnormal coronary arteries, 6 (9 percent) were reported to be normal. In four patients with abnormal scintigrams, the diagnosis of coronary artery disease was based on an inconsistent pattern. In three of these the pattern was related to isolated apical defects and in one it was related to apparent soft tissue attenuation. ''Consistent'' scintigraphic defects, seen frequently in patients with normal coronary arteries, in whom they are usually associated with an abnormal left ventricle. In patients with normal coronary arteries, ''inconsistent'' thallium defects are probably related to soft tissue attenuation or to normal apical thinning. Although defects caused by isolated apical abnormalities and soft tissue attenuation are also seen in patients with coronary diseases and add somewhat to scintigraphic sensitivity, they are a rare cause of diagnostic scintigraphic abnormalities in patients with coronary disease. The incidence of false positive thallium scintigrams could be reduced and overall accuracy improved by careful attention to the pattern of thallium defects

[en] Myocardial perfusion imaging during exercise stress and at rest has improved the diagnostic accuracy in patients with chest pain syndrome and those with known ischaemic heart disease being evaluated prior to or after coronary bypass surgery. This work plus subsequent reports further defined the diagnostic role of myocardial perfusion imaging at rest and exercise. (Auth.)

[en] Previous studies by Bailey et al. (1977) and Ritchie et al. (1977) concluded that excercise thallium-201 myocardial perfusion imaging provided a useful adjunct to conventional exercise testing in the investigation of patients with chest pain due to suspected coronary artery disease. This report compares rest and exercise electrocardiography and thallium-201 myocardial perfusion scanning in 74 patients with chest pain thought due to coronary artery disease. (Auth.)

[en] To compare serial functional and perfusion scintigraphic changes after myocardial infarction, we performed left ventricular (LV) cineangiograms and thallium (TI)-201 myocardial perfusion scintigrams before and 1 hour, 2 days, 9 days, and 1 month after closed chest coronary occlusion in 14 dogs as survival permitted. Survivors were studied with technetium-99m (stannous) pyrophosphate (TcPYP) scintigrams at 48 hours, and at postmortem examination infarction was documented and measured after nitroblue tetrazolium (NBT) staining. The TcPYP image was abnormal in 10 dogs, each of which had infarcts on NBT staining measuring 3 to 23 gm. In all 14 dogs, perfusion scintigrams became abnormal and LV ejection fraction (EF) fell when measured within 48 hours of occlusion. In the nine late survivors studied over 1 week after the event, perfusion scintigrams and EF improved in those which developed infarcts and normalized in those without infarction. The decrement in LVEF after coronary occlusion generally showed serial improvement and correlated with the size of the defect in the accompanying TI-201 scintigram. TI-201 defect size seen in late studies correlated well with NBT infarct size and TcPYP image infarct size, as it did with the decrement in LVEF noted in late studies. The results suggest that early perfusion scintigrams together with TcPYP images may be useful for estimating the amount of reversible dysfunction after coronary occlusion

[en] Exercise electrocardiography and thallium scanning were performed a mean of 24 days after uncomplicated acute myocardial infarction in 103 patients, aged 36 to 60 years, who also underwent coronary angiography. The purpose of the study was to determine the ability of the noninvasive tests to predict multivessel coronary artery disease (CAD) and prognosis. Patients were followed up to document medical complications (incidence 12%: 3 deaths, 1 resuscitated cardiac arrest, 4 recurrent infarctions, 4 admissions with unstable angina) and combined events (medical events or bypass surgery, incidence 23%). The sensitivity, specificity and predictive accuracy for predicting multivessel CAD were 64%, 77% and 64% for a positive exercise electrocardiographic (ECG) response, 64%, 88% and 80% for a remote thallium defect, and 42%, 96% and 88% for a combination of the 2 tests. With 2 tests yielding negative findings the probability of multivessel CAD was 13%. No variable (positive exercise ECG response, remote thallium defect and presence of multivessel CAD) predicted medical events, although there were nonsignificant trends to more events in patients with any of those findings. The relative risk of combined events was 2.5 (p less than 0.05) for a positive exercise ECG response; 1.8 (NS) for a remote thallium defect; 2.6 (p less than 0.05) for multivessel CAD; and 3.1 (p less than 0.025) for both positive ECG response and remote defect. A combination of exercise electrocardiography and thallium scanning early after acute myocardial infarction helps to identify subsets of patients with high and low probabilities of multivessel CAD and combined medical or surgical events

[en] To determine whether cardiomyopathy could be distinguished from coronary artery disease, we used thallium scanning to study 25 patients with severe left ventricular dysfunction and chronic heart failure. Ten patients had normal coronary arteries and idiopathic cardiomyopathy (ejection fraction 20 +/- 5%), and 15 patients had multivessel coronary disease and left ventricular dysfunction (ejection fraction 25 +/- 6%). The exercise time and maximal heart rate were similar in the two groups. Two patients with cardiomyopathy and 11 with coronary artery disease had a positive exercise ECG (p<0.05). Thallium scans showed perfusion defects in all 25 patients. The perfusion defects were complete in nine coronary artery disease patients (60%) and in one patient (10%) with cardiomyopathy (p<0.05). Extensive defects involving more than 40% of the left ventricular circumference, the number of segments involved, redistribution on the 4-hour scan, lung uptake and ventricular size were similar in the two groups. Perfusion defects on thallium scanning can occur in patients with idiopathic dilated cardiomyopathy and chronic heart failure. Thallium scanning cannot be reliably used in patients with chronic heart failure to distinguish coronary artery disease from cardiomyopathy unless complete defects are present

[en] In 61 patients with single vessel coronary artery disease (70 percent or greater obstruction of luminal diameter in only one vessel) and no previous myocardial infarction, the sites of ischemic changes on 12 lead exercise electrocardiography and on thallium-201 myocardial perfusion scanning were related to the obstructed coronary artery. The site of exercise-induced S-T segment depression did not identify which coronary artery was obstructed. In the 37 patients with left anterior descending coronary artery disease S-T depression was most often seen in the inferior leads and leads V4 to V6, and in the 18 patients with right coronary artery disease and in the 6 patients with left circumflex artery disease S-T depression was most often seen in leads V5 and V6. Although S-T segment elevation was uncommon in most leads, it occurred in lead V1 or a VL, or both, in 51 percent of the patients with left anterior descending coronary artery disease. A reversible anterior defect on exercise thallium scanning correlated with left anterior descending coronary artery disease (probability [p] less than 0.0001) and a reversible inferior thallium defect correlated with right coronary or left circumflex artery disease (p less than 0.0001). In patients with single vessel disease, the site of S-T segment depression does not identify the obstructed coronary artery; S-T segment elevation in lead V1 or aVL, or both, identifies left anterior descending coronary artery disease; and the site of reversible perfusion defect on thallium scanning identifies the site of myocardial ischemia and the obstructed coronary artery

[en] To determine whether cardiomyopathy could be distinguished from coronary artery disease, we used thallium scanning to study 25 patients with severe left ventricular dysfunction and chronic heart failure. Ten patients had normal coronary arteries and idiopathic cardiomyopathy (ejection fraction 20 +/- 5%), and 15 patients had multivessel coronary disease and left ventricular dysfunction (ejection fraction 25 +/- 6%). The exercise time and maximal heart rate were similar in the two groups. Two patients with cardiomyopathy and 11 with coronary artery disease had a positive exercise ECG (p less than 0.05). Thallium scans showed perfusion defects in all 25 patients. The perfusion defects were complete in nine coronary artery disease patients (60%) and in one patient (10%) with cardiomyopathy (p less than 0.05). Extensive defects involving more than 40% of the left ventricular circumference, the number of segments involved, redistribution on the 4-hour scan, lung uptake and ventricular size were similar in the two groups. Perfusion defects on thallium scanning can occur in patients with idiopathic dilated cardiomyopathy and chronic heart failure. Thallium scanning cannot be reliably used in patients with chronic heart failure to distinguish coronary artery disease from cardiomyopathy unless complete defects are present