[Indications for PTCA for the infarcted myocardium without redistribution by T1-201 myocardial scintigraphy: the role of two-dimensional echocardiography].

Persistent myocardial hypoperfusion in delayed images demonstrated by preoperative exercise T1-201 myocardial scintigraphy may improve after PTCA. The purpose of this study was to test whether PTCA-induced improvement could be anticipated by means of preoperative two-dimensional echocardiography and exercise T1-201 myocardial scintigraphy. The subjects consisted of 24 patients with prior myocardial infarction, in whom serial exercise T1-201 myocardial scintigraphy had been performed during treadmill exercise testing. The patients were divided into three groups according to the results of two-dimensional echocardiography (Group I: eight patients with hypokinesis in the infarct zone; Group II: eight patients with akinesis without a thin wall in the infarct zone; Group III: eight patients with akinesis with a thin wall in the infarct zone). Results were as follows: 1. There was no significant difference in initial T1-uptake in all the 24 patients before and after PTCA, though significantly increased uptakes were observed in Groups I and II after PTCA. 2. There were significant differences in preoperative initial T1-uptakes among the three groups. 3. In Group II, the patients with postoperative scintigraphic improvement had significantly higher preoperative initial T1-uptakes. 4. The postoperative improvement of myocardial perfusion was accompanied by improvement in wall motion. Therefore, an infarct zone without delayed redistribution in T1-201 myocardial scintigraphy does not necessarily indicate scar tissue. However, it may represent hypokinetic or akinetic areas without thin walls on two-dimensional echocardiograms, suggesting a hibernating myocardial state due to chronic intermittent episodes of myocardial ischemia. In such cases, improvement of myocardial perfusion after PTCA can be expected.