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)
Sudden cardiac death due to
lethal arythmia
