Morphological changes in myocardial infarction Flashcards
When will you see Reversible injury with no change in gross features or Little/no microscopic features?
0-1hr
Relaxation myofibrils, glycogen loss, mitochondrial swelling
When will you see Waviness fibers at border In sarcolemma disruption with mitochondrial amorphous densities
.5 to 4 hours, will have no gross features differences
When will you see early coagulation necrosis, Edema, and hemorrage? There will be gross dark modeling.
4 - 12 hours
When will you see ongoing coagulation necrosis,pyknosis of nuclei, hypereosinophilia, marginal contraction band necrosis, early neutrophilic infiltrate with dark modeling
12 to 24 hours
When will you see coagulation necrosis with the loss of nuclei and striations, brisk interstitial infiltrates of neutrophils, and modeling with yellow tan infarct centers
One to three days
When will you see the beginning disintegration of dead myofibers would dying neutrophils, early Phagocytosis of dead cells by macrophages, a hyperemic a border with central yellow tan softening
3 to 7 days
When would you see a well developed phagocytosis of dead cells, granulation tissue at margins and maxillary yellow tan and soft with depressed red tan margins
7 to 10 days
When would you see well-established granulation tissue with the new blood vessels, and COLLAGEN deposition, with red great depressed infarct borders
10 to 14 days
When would you see increase collagen deposition in a gray white scar
2 to 8 weeks
When is the dense collagenous scar complete
Greater than two months
When is injury irreversible
.5 to 4 hours with wavy fibers
What can occur 24 hours post acute MI aka early complications
Life-threatening arrhythmias with contracttile dysfunction, shock
Number one cause of death sometimes occur within one hour of onset
It’s contractile dysfunction that leads to the cardiogenic shock
What do you need to be worried about three days post ami
Rupture to the Septal, wall, papillary (mr) - Macrophages spill out
Acute Pericarditis - blood in sac restrains heart and can cause tamponade/hemodynamics collapse
Myocardial rupture typically occurs 2 to 4 days post from a transmutation infarct
Rf: Increased age, first mi, abs of LVH
What do you need to worry about two weeks post myocardial infarction
Chronic Pericarditis a.k.a. dressler syndrome
Ventricular aneurysm from thin wall remodeling from large trans mural infarct w expansion
continued risk of heart failure, life-threatening arrhythmias fibrillation
Progressive CHF
What are the risk factors for a myocardial rupture
Age, personally, absence of left ventricular hypertrophy
