Myocardial perfusion defects in ischemic heart disease visualized by semiselective 133Xe injections: correlations with left ventricular angiography

Regional myocardial perfusion abnormalities on xenon-133 imaging in patients with angina pectoris and normal coronary arteries

With use of semiselective xenon-133 injections and gamma camera recording, myocardial scintigrams were obtained in a series of 20 patients with angina pectoris, abnormal exercise electrocardiograms and normal coronary arteries. Ten patients (Group I) exhibited localized perfusion defects and the other 10 (Group II) a hjemogenous uptake of the tracer. Group I was characterized by more past myocardial infarctions and, most significantly, by male preponderance (P less than 0.001). Computer analysis of regional xenon-133 washout curves revealed that every patient in Group I had a reduced flow rate in the area of the perfusion defect (P less than 0.001). A comparison of this group with 26 patients with similarly abnormal scintigrams but coronary arterial obstruction revealed that myocardial perfusion was 16 to 18 percent greater in the group with normal coronary arteries. In three patients of this group, myocardial perfusion rates were not augmented by atrial pacing in contrast to the response in patients with coronary arterial obstruction. The data demonstrated localized perfusion abnormalities in half of the patients with angina pectoris and normal coronary arteries and constitute evidence that a metabolic disorder is not the sole mechanism for ischemia in this syndrome.