Formation of coronary arterial thrombi in relation to onset of necrosis in acute myocardial infarction in man. A clinical and autoradiographic study.

The presence of radioactivity in coronary arterial thrombi was studied at necropsy by autoradiography in 12 patients with acute myocardial infarction. Seven patients had been given 125I-and five patients 131I-labeled fibrinogen. With a short interval (less than 10 hours) between onset of symptoms and injection of fibrinogen the entire thrombus was radioactive in four of five patients, whereas with longer time intervals only parts or none of the thrombus contained detectable radioactivity. The findings give further evidence that thrombus formation in acute myocardial infarction probably is a slow process and that the major part of the thrombus may form after the onset of necrosis.