A 63-year-old woman develops free wall rupture 4 days after an anterior STEMI treated with thrombolysis. Post-mortem reveals coagulation necrosis with prominent neutrophilic infiltration, early macrophage ingestion, and beginning of granulation tissue. This temporal morphological pattern corresponds to which stage of myocardial infarction?
- A 1–3 days post-infarction
- B 7–10 days post-infarction
- C 3–7 days post-infarction ✓
- D 10–14 days post-infarction
Explanation
At 3–7 days post-infarction, the infarcted myocardium shows a heavy neutrophilic infiltrate that is at peak intensity around day 3–4, with early monocyte-macrophage ingestion of necrotic debris beginning around day 5–7. Granulation tissue with neovascularization starts forming at the margins of the infarct by day 7. This is the period of maximum softening of the myocardial wall (due to enzymatic degradation by neutrophils) and the highest risk of mechanical complications: free wall rupture, papillary muscle rupture, and ventricular septal defect. The coagulation necrosis is established but the necrotic cardiomyocytes are being digested.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.