[Myocardial infarct--morphology and development]

Exact pathological investigations revealed 90% of transmural infarctions to be caused by thrombotic occlusion of "Infarction branch". This is the reason for and not the consequence of the myocardial infarction. The myogenic theory could be disproved for the overwhelming majority of cases. The subendocardial infarction is caused by stenosed three-vessel-disease occasionally combined with severe anemia or attacks of tachycardia. In about 30% of cases fibrinous pericarditis could be found over the infarction area. Mural thromboses were detected in about one third of the transmural infarctions, a myocardial rupture was found in 10 to 15% of autopsies. A ventricular aneurysm developed in 5 to 10% of those cases, who survived more than 3 months. In cases of sudden death a severe stenosis or occlusion of one or more coronary vessels were found in more than 80%. A fresh thrombotic occlusion was also found due to rupture of arteriosclerotic plaques. An infarction is in this condition often not detectable, because the time between the onset of the attack and death was too short to develop a myocardial necrosis.