The diagnostic value and clinical significance of light exercise 201T1 ECT in coronary artery disease

To examine the clinical significance of scintigraphic transient perfusion defects preceding the occurrence of anginal pain and ischemic ST depression, we performed both maximal and light exercise thallium-201 emission computed tomography in 13 patients with effort angina pectoris. The target heart rate in the light test was set at 80% of the peak heart rate in the maximal test. The scintigraphic transient perfusion defect was observed in all cases in both tests, while the incidence of anginal pain and/or ischemic ST depression was lower in the light test (5/13 cases) comparing to the maximal test (13/13 cases). However, the number of defect segments in the light test was smaller than that in the maximal test (13 vs 19 segments). In the former 13 segments, the initial relative activity in the maximal test was not significantly different from that in the light test (69.4 +/- 9.3 vs 70.1 +/- 10.0%). These results suggest that the light test can precipitate a transient perfusion defect preceding anginal pain and/or ischemic ST depression, therefore the light test is useful to detect coronary artery disease in patients who cannot perform the maximal test.