Ischemic Heart Disease Flashcards
4 causes of decreased blood flow
- Fixed atherosclerotic narrowing (stable plaque)
- acute plaque change
- thrombosis overlying ruptured plaque
- vasospasm
__% narrowing causes ischemia with exercise
___% narrowing causes ischemia with rest
70%
90%
most dangerous acute plaque change lesions
moderately stenoic (lipid rich atheromas with soft lipid cores)
4 syndromes of IHD
Angina pectoris
MI
Chronic ischemic HD
Sudden cardiac death
3 patterns of angina pectoris
stable - physical activity or excitement (chronic stenoising of CAs)
Prinzmetal - CA spasm at rest
Unstable - via disruption of plaque with superimposed partial thrombosis, progressive
___% MI due to aacute plaque change > thrombosis
___% due to vasospasm, emboli, or unexplained
90%
10%
Transmural MI
full thickness of ventricular wall
one vessel’s distribution
fixed coronary obstruction AND acute plaqye change > complete obstructive thrombosis
Subendocardial MI
necrosis limited to inner 1/3
may extend beyond distribution of 1 vessel
Fixed CA obstruction w/acute plaque change
**but **nonocculisive thrombus **or **lysis of thrombus or HTN
loss of contractility occurs at ___% ischemia
60%
irreversible damage occurs at ___min
20-40 minutes
order of commonly occluded CA
LAD
RCA
LCA
progression of MI gross morphology
<12 hour not apparent (tertazolium stain at 3hr)
12-24hr - dark redblue mottling
1-14d - yellow tan area > yellow centrally with hyperemic periph
>2wks scar formation
histo progression MI
4-12hr - wavy fibers
12hr-7d - coagulative necrosis (acute inflam > phagocytosis)
7-14d granulation tissue and collagen depo
>14d - scar > dense fibrous scar
reperfusion injury micro
necrosis with contraction bands due to influx of Ca
MI clinical presentation
Chest Pain
Rapid weak pulse
diaphoresis
dysnea (due to pul edema)
