Details
Section of myocardium from a 59 year old male.
Myocardial infarction refers to irreversible damage to the heart due to ischemia. Complications include rupture of the myocardium, ischemic dilated cardiomyopathy and ventricular aneurysm.
The macroscopic appearance of myocardial infarction varies with time following the ischemic event and correlates with the degree of tissue injury repair. Up to 24 hours following injury there may be no macroscopic evidence or minor dark mottling of the myocardium. Between 7-10 days the area of injury becomes depressed, softened, and hyperemic around its edges. Between 3 and 8 weeks a grossly evident gray-white scar forms, as is present in this case.
Myocardial rupture can be divided into three types: type I is an abrupt slit like tear associated with early infarction while type II demonstrates erosion of the infarcted myocardium and typically occurs between 7-10 days following ischemic injury. Type III involves aneurysmal dilatation with rupture at a point in the thinned myocardium and is typically associated with old infarcts; the depicted myocardial rupture is type III and involves the posterior myocardium in a heart with apparent left ventricular hypertrophy and increased pericardial adipose tissue.
See related content for references:
1) Bones, BM, et al. Eur Heart J. 2014 Aug 14;35(31):2060-8.