[Comparison of two-dimensional echocardiography and Tl-201 SPECT in the evaluation of ischemic heart disease]

Abstract

To ascertain the influence of severity of coronary stenosis and the presence or absence of collateral circulations on echocardiographic (2DE) asynergy or abnormal myocardial perfusion by exercise Tl-201 SPECT, we performed a correlative study of 40 patients undergoing coronary angiography, including 27 with myocardial infarction and 13 with angina pectoris, whose mean age was 55 years. Each view of the left ventricle (LV) obtained by both methods was assigned to five segments; i.e., anterior, septal, inferior, lateral and apical. The correlation of abnormal segments was investigated using both methods. The segments showing a severe perfusion defect coincided those with severe asynergy. Among 116 segments with normal perfusion, 99 (85%) revealed normal wall motion, but the remaining 15% showed asynergy. Among 84 segments with abnormal myocardial perfusion, 26 (31%) had normal wall motion, and most of these were non-infarcted regions. Concerning the severity of coronary artery stenosis, greater than 99% coronary arterial stenoses existed in most of the segments showing a complete defect or incomplete redistribution on Tl-201 SPECT and akinesis or hypokinesis on 2DE. Collaterals were observed in 22% of the segments with a complete defect and 66% of segments with incomplete redistribution; whereas, there was no significant correlation between the severity of LV wall motion abnormality and the presence or absence of collaterals. The severity of asynergy is possibly related to the severity of abnormal myocardial perfusion, however, asynergy could occur at the site of ischemic regions where Tl-201 SPECT can not detect the abnormalities. In patients with myocardial infarction who show incomplete redistribution by exercise Tl-201 SPECT, temporal ischemia of collaterals might cause such a perfusion abnormality.