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41 Cards in this Set
- Front
- Back
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What is compromised blood supply or increased oxygen demand (supply-demand mismatch)?
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ISCHEMIA
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What is cell death due to ischemia?
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INFARCTION
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What is chronic ischemia +/- infarction?
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ISCHEMIC HEART DISEASE
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What is the main cause of Ischemic Heart Disease?
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Coronary atherosclerosis
(anything that decreases oxygen delivery or increases oxygen demand) |
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What is the pathophysiology of Ischemic Heart Disease?
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- supply demand mismatch
- myocardial ischemia in affected region - myocardial infarction - other complications |
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Coronary arteries
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- RIGHT CORONARY ARTERY ( RV, Posterior LV / Septum {75%}, posterior papillary muscle, AV & SA nodes)
- LEFT ANTERIOR DESCENDING (anterior septum) - LEFT CIRCUMFLEX (lateral LV, posterior LV / Septum {25%}) |
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Pathophysiology of Acute MI
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- acute change in coronary artery plaque
- thrombosis - ischemic damage to myocardium - myocyte necrosis - other complications |
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PIC OF?
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RUPTURE OF VULNERABLE PLAQUE
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PIC OF?
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RUPTURE AND THROMBOSIS OF VULNERABLE PLAQUE
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PIC OF?
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THROMBOSIS OF CORONARY ARTERY
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PIC OF?
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THROMBOSIS OF CORONARY ARTERY
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PIC OF?
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THROMBOSIS OF CORONARY ARTERY
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Cells involved in MI
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- neutrophils
- macrophages - fibroblasts |
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Early changes in MI Histology (<24hrs)
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- initially no visible histology
- coagulative necrosis ("Contraction Band Necrosis") - Neutrophil response |
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PIC OF?
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CONTRACTION BAND NECROSIS
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Middle changes in MI Histology (1-3 days)
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- neutrophils
- cellular debris - macrophages |
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Later changes in MI Histology (3-7days)
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- macrophages
- phagocytosis - fibroblasts |
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When is the the greatest risk of myocardial rupture?
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4-7 days
- weak tissue and blood can leak out into the pericardium |
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Healing changes in MI histology (>7days)
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- fibroblasts
- neovascularization - collagen / fibrin * result is myocardial scar |
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PIC OF?
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MI 1-3 DAYS
- Pale, soft myocardium |
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Coronary Atherosclerosis Timeline
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- Nothing ~ 0 days
- Neutrophils ~ 1-3 days - Macrophages ~ 3-7 days - Fibroblasts ~ >7days - Scar ~ weeks |
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Complications of MI
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- arrhythmia
- myocardial rupture - pericarditis - mural thrombus - ventricular aneurysm - ventricular remodelling |
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Arrhythmias from MI
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- MYOCARDIAL IRRITABILITY
- Heart Block (depending on location) - Bradycardia, ventricular tachycardia, premature ventricular contractions |
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PIC OF?
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VENTRICULAR FREE WALL RUPTURE
- Hemopericardium |
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PIC OF?
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SEPTUM RUPTURE
- causes acute VSD with left to right shunt |
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PIC OF?
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PAPILLARY MUSCLE RUPTURE
- leads to acute mitral valve insufficiency |
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What is Dressler's Syndrome?
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FIBRINOUS PERICARDITIS
* after acute MI ~ 1-7 days later (acute inflammatory exudate) ~ 6-8 weeks later ("autoimmune") - after bypass graft surgery ~ POST - PERICARDOTOMY SYNDROME |
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PIC OF?
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MURAL THROMBUS
- Akinesis / hypokinesis of infarcted myocardium ~ blood pools on endocardial surface ~ thrombus forms * Complication : embolization of thrombus leading to stroke or gangrene |
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PIC OF?
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VENTRICULAR ANEURYSM
- infarcted myocardium is thinned and balloons outward with forceful contractions of adjacent myocardium - thrombus can form in aneurysm |
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What is ventricular remodeling?
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- infarcted myocardium dies (SCAR TISSUE)
- surrounding myocardium HYPERTROPHIES * Result = zones of fibrosis with surrounding hypertrophy ~ myocardium can become thick and stiffened |
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What it the pathophysiology of sudden cardiac death?
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- patient has severe coronary artery sclerosis
* NO OCCLUSIVE THROMBUS and / or NO MI - death is due to arrhythimia and not infarction ~ typically V-Fib |
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Coronary artery bypass graph treatment
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- Saphenous vein or synthetic vein used
- INTERNAL MAMMARY ARTERY (aka internal thoracic artery) grafted to LAD is best result |
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Percutaneous coronary intervention treatment
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- aka percutaneous transluminal coronary angioplasty (PTCA) or angioplasty
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STABLE ANGINA
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- imbalance in coronary perfusion and oxygen demand
- exercise induced - chronic atherosclerosis * stable angina, stable plaque |
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UNSTABLE ANGINA
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- myocardial ischemia
- thrombosis of coronary artery from plaque pathology - "preinfarction angina" - at rest or minimal exertion |
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What is Prinzmetal Angina?
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- Episodic ischemia from coronary vasospasm
- occurs at rest |
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Reperfusion injury
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- blood flow restored by PTCA, thrombolysis
- usually ~30mins to 3-4 hrs after ischemic event - damaged myocardium is susceptible to hemorrhage, arrhythmia, further ischemia |
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Myocardial Stunning
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- myocytes not lethally damaged can recover function in a few days with reperfusion
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Myocardial Hibernating
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- myocytes that have chronic sublethal ischemia may hibernate for days to weeks then recover function later
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SERUM BIOMARKERS FOR MI
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- TROPONIN T & I
~ sensitive and specific (bc not normally found in circulation) - CK-MB ~sensitive but not as specific ~ MB can also be found in skeletal muscle * best diagnosis is combo of both |
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SERUM BIOMARKERS TIMELINE
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- MYOGLOBIN: out 1st, gone 1st; (-)sens/(-)spec
- CK-MB: out 2nd, gone 2nd; (+)sens/(-)spec - TROPONINS: out last, gone last; (+)sens/(+)spec |
