[Mechanism of exercise-induced ST segment deviation in myocardial infarction: a 201T1-myocardial scintigraphic study]

Exercise-induced ST segment deviation was investigated using thallium-201 myocardial scintigraphy and correlated with coronary artery lesions in 25 patients with old myocardial infarction. Seven of eight patients without ST deviation showed no reversible perfusion defect by near maximal exercise, and six had no significant stenosis in the coronary arteries perfusing the non-infarcted area. During exercise, ST segment depression was induced in 12 patients and six of them developed a reversible perfusion defect in the non-infarcted area, associated with significant stenosis of the corresponding coronary arteries. Remaining six patients, however, did not show a reversible perfusion defect and four of them had no significant stenosis of the coronary arteries perfusing the non-infarcted area. In nine patients with exercise-induced ST segment elevation in leads with Q waves, a reversible perfusion defect was not detected in seven (78%) and five (71%) of them had no significant coronary artery stenosis as well. Four patients developed both ST segment elevation in leads with Q waves and ST segment depression in other leads. One patient who had significant coronary artery stenosis in the non-infarcted area and showed a reversible perfusion defect developed 1.5 mm ST elevation in II, III, a VF leads and 4 mm ST depression in precordial leads. In the remaining three patients who did not show a reversible perfusion defect and significant coronary artery stenosis in the non-infarcted area, ST depressions were less than 2 mm.(ABSTRACT TRUNCATED AT 250 WORDS)