ACS Flashcards
ACS triggers
physical activity, emotional stress, SNS activation
endogenous anti thromotics
antithrombin III (enhanced w/ heparin), protein C and S (degrade Va and VIIIa), tissue factor inhib, tPA, prostacyclin (ups platelet cAMP and inhibits activation), NO
how much ischemia can cause infarct
20-30 min
how long to dissolve thrombus
12-24 hours
transmural infarct vs subendocardial
spans entire thickness of myocardium vs only innermost layers (more susceptible to ischemia)
factors determining amount of tissue death
mass perfused, magnitude/duration of ischemia, oxygen demand, collateral coronary flow, amount of reperfusion, inflammatory response
LAD occlusion
anterior LV, anterior 2/3 septum, apical LV
LCx occlusion
lateral LV, poserolateral LV
RCA occlusion
posterior LV, posterior 1/3 septum, posterior pap muscle, inferior
when does irreversible injury occur
in 20 mins
describe early changes during MI
shift to anaerobic, lactic acid accumulates, ATP drops, high Na causes cellular edema, abnormal electrolytes causes risk for arrhythmia (VT and V fib)
when does dark mottling of myocardium begin
4-12 hours
tan necrotic center forms?
1-3 days
when is injury maximally yellow tan, depressed red tan borders
3-14 days
when gray white scar forming
2-8 weeks
mature scar from MI?
more than 2 months
micro of MI less than 4 hours
no change, some wavy fibers
micro MI 4-12 hrs
early coag necrosis, edema, wavy fibers
micro MI 12-24 hrs
coag necrosis, pyknosis, contraction bands, early PMNs
micro MI 1-3 days
extensive coag necrosis, loss of nuclei, interstitial PMNs
micro MI 3-14 days
dying PMNs, disintegrating dead myocytes, macros and granulation tissue at border
micro MI 2-8 weeks
loss of cells, more collagen
micro MI over 2 months
dense collagenous scar
contrast hypokinesis, akinesis, dyskinesis
in order: reduced contraction, no contraction, local region bulging outward
