Thallium-201 reverse redistribution at rest

A new pattern of myocardial infarction, reverse redistribution at rest (RRD), was recently described in patients with evolving acute myocardial infarction (AMI) treated with streptokinase (STK). This pattern, observed on day 10th post-STK resting Tl-201, was associated with non transmural infarction and patency of infarct related coronary artery. In this study we assess the frequency of scintigraphic patterns characteristic of infarction 7-9 days after the onset of symptoms in 35 control patients (Group A) and in 27 patients treated with intravenous STK (Group B). Scintigraphic abnormalities compatible with AMI were observed in 98% of patients. RRD is associated with AMI in 23% of control and in 22% of STK treated patients. The RRD pattern results more frequently associated with inferior than with anterior AMI (93% in inferior vs. 7% in anterior AMI; p=0.0018). A significant reduction of the severity of the myocardial perfusion defect observed in the scan performed immediatly after the admission to Coronary Care Unit was observed in the 8th day scan, in both groups. While the degree of perfusion improvement observed in Group A was not significantly higher than that observed in Group B, the CK-MB time to peak in Group A is reached significantly later than in Group B. According, it can be supposed that mechanisms other than STK induced recanalization reestablish coronary blood flow in the jeopardized myocardium