[Assessment of regional wall motion and myocardial flow in patients with dilated cardiomyopathy using Tl-201 SPECT during dobutamine infusion].

The present study clarified the relationship between wall motion and myocardial flow in dilated cardiomyopathy (DCM). Two-dimensional echocardiography (2-DE) was performed in 14 patients before and after dobutamine (DOB) drip infusion (8 micrograms/kg/min). Thallium-201 emission computed tomography (ECT) was performed after dobutamine infusion and three hours thereafter. The left ventricle was divided into nine segments. In each segment, the degrees of defects were scored from 0 (normal) to 3 (complete defect), and the severity of wall motion abnormalities was scored from 0 (normal) to 3 (akinesis) by visual inspection. 1. Perfusion defects on ECT images were observed during dobutamine infusion in all patients. Redistribution was observed in nine of 14 (64%) patients. 2. During infusion, 38 (81%) of 47 segments without defects showed normal wall motion, but 44 (86%) of 51 segments with defects showed wall motion abnormalities. 3. Redistribution was observed in 18 (35%) of 51 segments, and these segments showed lower incidence of wall motion abnormalities as compared to the other segments (94% vs 45%, p less than 0.001). 4. After infusion, the segments with redistribution frequently showed improved wall motion as compared to the other segments (56% vs 18%, p less than 0.05). These results indicate that redistribution on the ECT image is observed in some patients with dilated cardiomyopathy after dobutamine administration. This may be due to the capacity of the drug to increase myocardial flow in proportion to the increase of oxygen demand.