ASSESSMENT OF RESIDUAL TISSUE VIABILITY BY EXERCISE TESTING IN RECENTMYOCARDIAL-INFARCTION - COMPARISON OF THE ELECTROCARDIOGRAM AND MYOCARDIAL PERFUSION SCINTIGRAPHY

The assessment of residual myocardial viability in infarcted areas is relevant for subsequent management and prognosis but requires expensiv e technology. To evaluate the possibility that simple, easily obtainab le clinical markers may detect the presence of within-infarct viable t issue, the significance of exercise-induced ST elevation occurring in leads exploring the area of a recent Q wave myocardial infarction was assessed. Twenty-five patients with recent (< 6 months) myocardial inf arction were studied. All had angiographically documented coronary art ery disease, diagnostic Q waves (n = 24) or negative T waves (n = 25) on the rest 12-lead electrocardiogram and exhibited during exercise gr eater-than-or-equal-to 1.5 mm ST segment elevation (n = 17) or isolate d T wave pseudonormalization (n = 8) in the infarct-related leads. ST- T wave changes were reproduced in all patients during thallium-201 exe rcise myocardial scintigraphy. A fixed perfusion defect was observed i n 24 of the 25 patients. A reversible defect was seen in 16 (94%) of 1 7 patients who exhibited transient ST elevation during exercise but in only 4 (50%) of the 8 patients who had only T wave pseudonormalizatio n. In conclusion, in patients with recent myocardial infarction, analy sis of simple ST segment variables obtained during exercise testing ma y allow a first-line discrimination of those who may potentially benef it from a revascularization procedure.