[Indium III monoclonal antimyosin antibody scintigraphy for the detection of chronic myocardial infarction apart from the acute phase].

Fab antimyosin scintigraphy has been shown to be sensitive and specific in detecting acute myocardial necrosis. This study was designed to evaluate the preoperative frequency of Indium-111 (In-111) antimyosin myocardial uptake in patients scheduled for coronary artery bypass surgery. The scintigraphic results were compared with other criteria of myocardial infarction (MI). Sixteen consecutive patients were included. Recent MI (1 to 3 months) were detected in four patients, with an accurate localization in three cases when compared to the classic criteria for MI. Two more patients had old Q wave MI: one did not show any uptake in the territory of MI whereas the second patient with a 21 year old infarct without recent acute coronary events showed an intense uptake consistent with the ECG and angiographic localization. Four other patients with stable angina showed limited uptakes that were unexpected, since there were no acute coronary events in their medical history, and ECG. Their left ventricle angiography were considered as normal. In these four cases, the scintigraphic location corresponded to a territory supplied by an occluded coronary artery (n = 2) or by a coronary artery with a tight stenosis requiring a bypass graft (n = 2). These antimyosin uptakes are probably related to small necroses which did not modify the ECG and did not alter the ventricular segmental wall motion. We conclude: 1) recent MI are detected by In-111 antimyosin scintigraphy; 2) In-111 antimyosin uptake may occur in patients without a diagnosis of recent myocardial infarction and correspond to older MI or limited necroses without detectable changes of the ECG and left ventricle angiography.