| Time after event |
Histopathologic findings |
| 4-6 hours |
Margination of polymorphonuclear leukocytes |
| 8-12 hours |
Diapedesis of polymorphonuclear leukocytes into the myocardial interstitial space |
| 1 day |
Hypereosinophilic fibers, nuclear pyknosis, coagulation necrosis, colliquative myocytolysis, edema, interstitial hemorrhage, contraction band necrosis, increase in neutrophilic infiltration |
| 2-3 days |
Marked polymorphonuclear infiltrate with extensive karyorrhexis, loss of myocyte nuclei |
| 4 days to 1 week |
Macrophage infiltration, early granulation tissue with fibroblast response and capillary proliferation at the edges |
| 7-14 days |
Granulation tissue with hemosiderin-laden macrophages; variable amount of lymphocytes, rare plasma cells and eosinophils; polymorphonuclear leukocytes have disappeared |
| 2-8 weeks |
Granulation tissue matures with increased collagen deposition, which becomes prominent and more dense |
| 2 Months |
Healed scar |
