Histology and Explanation of Acute myocardial infarct

Myocardial infarct - circumscribed area of ischemic necrosis - coagulative necrosis. In the first 12 - 24 hours, myocardial fibers are still well delineated, with intense eosinophilic (pink) cytoplasm, but lost their transversal striations and the nucleus (left side of the picture). Notice a few myocardial fibers showing hypertrophy (increased size of the fiber, irregular shape of the nuclei).


Recent myocardial infarct (in the first 12 - 24 hours): myocardial fibers are still well delineated, with intense eosinophilic (pink) cytoplasm, but lost their transversal striations and the nucleus. The interstitial space may be infiltrated with red blood cells. Make the distinction between interstitial leucocytes (small, outside the myocardial fibers) and the myocardial nucleus (should be central and unique, but is absent here).



Recent myocardial infarct (first 24 hours) (detail).