Ischemic Heart Disease
Terms
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- ischemic hrt disease
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imbalance of tissue perfusion and oxygen requirement
decreased coronary blood flow - exercise induced ischemia
- 50-75% narrowing of coronary cross section, adequate at rest
- critical stenosis
- >75% narrowing of coronary flow, problem at rest
- 4 ischemic syndromes
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MI
Angina Pectoris
Sudden Cardiac Death
Chronic ischemic Heart Disease - 12 hrs after MI
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Gross: no change
micro: wavy fibers, coagulation necrosis, edema - 24-48 hrs after MI
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gross: yellow
micro: hypereosinophilic, PMNs at border - 3-5 days after MI
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gross: tan yellow soft center, hyperemic borders
micro:lots of PMS, coag necr, loss of nuclei - Changes of serum in MI
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increased creatine kinase MB CK2
lactic acid dehydrogenase (LDH-1)
cardiac troponin contractile proteins released from injured muscle - What are the major coronary events leading to MI
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1)abrupt change or rupture in a stenosing atheroma (already more than 75% reduction)
2) platelets aggregate, activate, release ADP which further builds up aggreg
3) tissue thromboplastin is released activating extrinsic coag
4) platelets relase TXA2, serotonin, PF 3 and 4 causing coag and vasospasm
5) thrombus may become occlusive causing transmural AMI - 6-10 days after MI
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gross: yellow, depressed central, tan red margins
micro: GRANULATION TISSUE AT BORDER, mummified in center, MO at border - 10-14 days after MI
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gross: grey red borders, central tan yellow
micro: GRANULATION EVERYWHERE, collagen dep - What are the factors that determine the location and size of MI,
- CA involvement (LAD, RCA, LCCA), existance of vascular collaterals, underlying coronary disease
- Complications
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Arrhythmias, within first few hours,
heart block, AV nodal PostMI, BBB LAS
LV Failure
Progressive infarct
Pericarditis within 2-3 days, pain, rub
Embolism from mural thrombis when endocardium is involved
Rupture (5%)
ventricular Aneurysm - Why is a primary right ventricular infarct rare
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because it is thin walled and can be perfused directly from cahmber
when it happens is part of massive LV infarct - Difference between mural and subendocardial infarct
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Mural full thickness is most common, wave front phen
subendocardial most vulnerable least well perfuse, inner third of LV wall, multifocal or circumferential depending on coronary involvement - LAD infarct
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50%
anterior wall LV; anterior 2/3 septum - RCA infarct
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30%
posterior wall LV; post 1/3 of septum - LCCA
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20%
lateral wall LV - coronary abnormalities
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>75% reduction of cross sectional area of one major
typically wihin first 2-4 cm of LAD and LCCA, and proximal distal thirds of RCA - Systemic Changes after Mi
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fever
PMN up
fibrinogen and hepoglobin up (Acute phase reactants) - Electrocardial Changes after Mi
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inverted T
elevated ST segment
abnormal Q - When does pericarditis occur
- after 2-3 days
- when can you rupture
- 5-7 day is the weakest
- when is ventricular aneurysm risk high
- 2weeks to several months
- Hemopericardium
- cardiac tamponade
- interventrculare septal rupture
- L to R shunt, Acute RV failure
- rupture of papillary muscles
- acute mitral incompetence
- what is prinztmetals angina
- angina at rest, due to coronary spasm often ST elevated
- Sudden cardiac death
- dfined as unexpected death within an hour of onset of acute symptoms