This sqadia.com short video clip is the brief explanation of Pathology of Myocardial infarction.
Within 0–12 hours there is no visible macroscopic change. Infarcted muscle appears uncoloured on staining due to loss of oxidative enzymes. Non-infarcted muscles stains blue.
After 12-24 hours infarcted muscles appear pale with blotchy discoloration, highly eosinophilic with intercellular oedema.
After 24-72 hours dead area appears. Infarcted area excites an acute inflammatory response neutrophils infiltrate between dead cardiac muscle fibers.
After 3-10 days hyperaemic border develops around the yellow dead muscle. Organization of infarcted area replacement with vascular granulation tissue. Weeks to months late, white scar is formed. Due to progressive collagen deposition infarct is replaced by a collagenous scar.