Evolution of MI Flashcards
0-4 hours
Gross: none
Light microscopy: none
Risk: arrhythmia, CHF exacerbation, cardiogenic shock
4-12 hours
Gross: occluded artery, infarct, dark mottling; pale with tetrazolium stain
Light microscopy: early coagulation necrosis, edema, hemorrhage, wavy fibers
Risks: arrhythmia
12-24 hours
Gross: occluded artery, infarct, dark mottling; pale with tetrazolium staining
Light microscopy: contraction bands from reperfusion injury; release of necrotic cell content into blood; beginning of neutrophil migration
Risk: arrthymia
1-3 days
Gross: hyperemia
Light microscope: extensive coagulative necrosis; tissue surrounding infarct shows acute inflammation, neutrophil migration
Risk: fibrinous prericarditis
3-14 days
Gross: hyperemic border; central yellow-brown softening–maximally yellow and soft by 10 days
Light microscope: macrophage infiltration followed by granulation tissue
Risk: free wall rupture to tamponade, papillary muscle rupture, ventricular aneurysm, inter ventricular septal rupture due to Macrophages that have degraded important structural components
2 weeks to several months
Gross: recanalized artery, gray-white
Light microscope: contracted scar complete
Risk: Dressler’s syndrome
