[Pre-hospital and hospital thrombolytic therapy of acute myocardial infarction. Evaluation of initial myocardial ischemia and its reversibility by methoxy isobutyl isonitrile computed tomographic scintigraphy].

In order to assess initial myocardial perfusion, 20 mCi of Tc 99m MIBI were administered to 39 patients with suspected myocardial infarction less than 6 hours old. The injection was given on admission to the coronary care unit (n = 19) or by the emergency ambulance service at the patient's house (n = 20). For immediate availability, this myocardial tracer was labelled throughout the 24 hour period for 1 month and distributed to 4 emergency ambulance teams. The diagnosis of acute myocardial infarction was confirmed in 30 cases and 19 thrombolytic therapies were started either at home or on hospital admission. Myocardial scintigraphy was abnormal in all cases with confirmed infarction, in some cases before the ECG changes, and the results correlated perfectly with those of early angiography (36 hours). Repeat myocardial scintigraphy performed at 72 hours was used to assess response to therapy. The fixation of MIBI increased significantly after thrombolysis (p less than 0.001) but also after heparin alone (p less than 0.05). The scintigraphic improvement demonstrated the presence of viable myocardium at an earlier stage than analysis of wall notion but the presence of a stable defect at 72 hours did not indicate absence of viability. MIBI tomoscintigraphy is a non-invasive method for evaluating the benefits of thrombolytic therapy. It could be used to compare the efficacy of different thrombolytic agents or to appreciate the value of pre-hospital thrombolytic therapy with respect to thrombolysis started on hospital admission.