Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Case 3: Healed Myocardial Infarction
A 37-year-old female with a 22 year history of insulin-dependent diabetes mellitus was admitted to the hospital 10 hours prior to death complaining of chest pain and shortness of breath.
Three months before, she had begun to experience progressive weakness and for the previous 3 weeks she noticed increasing dyspnea on exertion and worsening of a chronic cough.
Autopsy showed a 340-gram heart with extensive transmural reddish discoloration of the anterolateral portion of the myocardium of the left ventricle.
There was severe atherosclerotic narrowing of all coronary arteries especially the left anterior descending artery.
The lungs showed pulmonary edema and early bronchopneumonia.
Images courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology
This is a gross photograph of a heart with areas of old healed myocardial infarction (scars) outlined by arrows.
This is a low-power photomicrograph of a healed myocardial infarction with a fibrous scar. Remaining normal tissue is on the left (1) and the fibrous connective tissue scar is on the right (2).
This is a higher-power photomicrograph of a healed myocardial infarction with a fibrous scar. Remaining normal tissue is at the top (1) and the fibrous connective tissue scar is at the bottom (2). Note the presence of occasional hypereosinophilic myocytes indicating recent acute ischemic injury to this region of old scar tissue (arrows).
This is another high-power photomicrograph of a healed myocardial infarction. Note the remaining normal myocytes (1), the fibrous connective tissue (2), and occasional hypereosinophilic myocytes indicating recent acute ischemic injury (arrow).
This is a high-power photomicrograph of a different region of this healed MI. Note the chronic inflammatory reaction (arrows) in this region suggesting that there had been ischemic injury to this area within the last several weeks to months.
This is a low-power photomicrograph of two sections of myocardial tissue stained with a trichrome stain to demonstrate fibrous connective tissue (blue). The section on the left is from a heart with a recent myocardial infarction. Notice the absence of fibrous connective tissue. The section on the right is from a heart with an old healed infarct and it contains extensive fibrous connective tissue scars.
This is a photomicrograph of a trichrome-stained section from a heart with an acute myocardial infarction. Note that there is little fibrous connective tissue. It is too early for scar formation to have taken place in this acute lesion.
This is a photomicrograph of a trichrome-stained section of heart containing an old healed myocardial infarction. The scar is composed of mature fibrous connective tissue (arrows).
This is a higher-power photomicrograph of a trichrome-stained section of heart containing an old healed MI. The scar tissue (mature fibrous connective tissue) is stained blue.