Table 4.

Histologic parameters of tissue damage and repair overtime in myocardial infarction (without reperfusion); see text for references

Myocardial histologic parameters (HE staining)	Earliest manifestation	Full development	Decrease/disappearance
Streched/wavy fibres	1–2 h
Coagulative necrosis: ‘hypereosinophilia’	1–3 h	1–3 days; hyper-eosinophilia and loss of striations	> 3 days: disintegration
Interstitial oedema	4–12 h
Coagulative necrosis: ‘nuclear changes’	12–24 (pyknosis, karyorrhexis)	1–3 days (loss of nuclei)	Depends on size of infarction
PMN infiltration	12–24 h	1–3 days	5–7 days
PMN karyorrhexis	1.5–2 days	3–5 days
Macrophages and lymphocytes	3–5 days	5–10 days (including ‘siderophages’)	10 days to 2 months
Vessel/endothelial sprouts*	5–10 days	10 days–4 weeks	4 weeks: disappearance of capillaries; some large dilated vessels persist
Fibroblast and young collagen*	5–10 days	2–4 weeks	After 4 weeks; depends on size of infarction;
Dense fibrosis	4 weeks	2–3 months	No

*Some authors summarize the vascular and early fibrotic changes as ‘granulation tissue’, which is maximal at 2–3 weeks