3.2a CVS Pathology 1 Flashcards
This can help predict if there is cardiomegaly or atrophy
Weight of the heart
Normal weight of the heart for males and females
Female: 250-300 gm
Male: 300-350 gm
Normal thickness of the free wall do the heart for RV and LV
RV: 0.3-0.5 cm
LV: 1.3-1.5 cm
This is important in recognizing hypertrophy and dilatation
Thickness of the free wall
This can mean the ff:
- Increase in organ size
- Greater heart weight
- Greater ventricular thickness
Hypertrophy
This mean refers to an enlarged chamber size accompanied by thinning of the left ventricle
Dilatation
This refers to an increase in cardiac weight or size (owing to hypertrophy or dilatation)
Cardiomegaly
Enumerate the layers of the heart (4)
- Endocardium
- Myocardium
- Pericardium
- Epicardium
Which layer of the heart is being described?
- Lines the chambers and valves
- Cardiac conduction system can be found here
Epicardium
It is a collection of specialized striate muscle cells
Cardiac myocytes
It is the functional intracellular contractile unit of cardiac muscle
Sarcomere
What are the regulatory proteins of the sarcomere? (2)
- Troponin
2. Tropomyosin
What is the importance of regulatory proteins (Troponin, tropomyosin)?
Important diagnostically: they are released to indicate myocardial injury
- It is the sac that encloses the heart
2. The outermost layer of the heart
Pericardium
It is the visceral pericardium
Epicardium
What area the specialized excitatory and conducting myocytes? (4)
- SA node
- AV node
- Bundle of His
- Right and left bundle branches
Cardiac myocytes relies almost entirely on this process for its energy needs
Ox phos
Differentiat epicardial coronary arteries from intramural arteries
Epicardial: run along external surface of the heart
Intramural: penetrate myocardium
What are the major epicardial coronary arteries? (3)
- Left anterior descending a. (LAD)
- Left circumflex a. (LCX)
- Right coronary artery
What does the LAD supply? (3)
- Anterior wall
- Anterior 2/3 of septum
- Entire apex
Circumferentially
What does LCX supply? (1)
Left posterolateral aspect of the heart
What does the right coronary artery supply? (2)
- Posterior 1/3 of septum
2. Inferior and posterior wall of the heart
These maintain unidirectional flow of blood through the heart
Cardiac valves
The function of _____ depends on the mobility, pliability, structural integrity of the leaflets (tricuspid, mitral) or cusps (aortic, pulmonic)
Heart valves
What are semilunar valves? (2)
- Aortic
2. Pulmonary
What are the atrioventricular valves? (2)
- Mitral
2. Tricuspid
These valves depend on the integrity and coordination of movement of the cuspal attachment
Semilunar valves (aortic, pulmonic)
These valves depend on:
- Leaflets and their attachments
- Tendinous connections to papillary muscle of ventricular wall
Atrioventricular valves (mitral, tricuspid)
What can cause regurgitation in the semilunar valves? (1)
Dilatation of aortic root
What can causes regurgitation in atrioventricular valves? (3)
- Left ventricular dilatation
- Ruptured tendon
- Papillary muscle dysfunction
What are the (3) pathological changes of valves?
- Damage to collagen (weakens leaflets; ie. mitral valve prolapse)
- Nodular calcification (ie. calcific aortic stenosis)
- Fibrotic thickening (ie. RHD)
Which cardiac pathology is being described:
1. Results from impaired cardiac function that renders heart muscle unable to maintain an output sufficient for the metabolic requirements of tissues and organs
- It is the final common pathway of many heart diseases
- Most often develop due to cumulative effects of chronic work overload or ischemic heart disease
CHF
Simply, it is defined as a state that develops when the heart fails to maintain adequate cardiac output to meet the demand of the body
CHF
Normal CO = ?
4200 mL/min
4-8 L/min
It is the volume of blood ejected
Cardiac output
Heart failure is characterized by? (3)
- Forward failure: diminished CO
- Backward failure: damming of blood in venous system
- Both
Compensatory mechanisms in CHF (3)
- Frank-Starling mechanism
- Myocardial hypertrophy
- Activation of neuronumoral systems
In this compensatory mechanism:
Greater volume of blood entering the heart during diastole (end diastolic volume) = greater volume of blood ejected during systole (stroke volume)
Frank-Starling mechanism
Compensatory mechanism:
- With or without cardiac chamber dilatation
- LVH –> increased contractility
- Left ventricular “remodeling” –> increased stroke volume
Myocardial hypertrophy
What happens in left ventricular remodeling? (3)
- Deposition of new sarcomeres
- Increased length and width of muscle fibers
- Increased weight of heart
It is an important indication of heart failure
Left ventricular remodeling
It is a compensatory response of the myocardium to increased mechanical work.
Myocardial hypertrophy
-the pattern of hypertrophy reflects the nature of the stimulus:
- In aortic or mitral valve regurgitation = volume overload
- In systemic HPN or aortic stenosis = pressure overload
Characterized by:
- Dilation with increased ventricular diameter
- Muscle mass and wall thickness (not necessarily be increased; may be normal or less than normal) are increased in proportion to diameter of chamber
- Deposition of sarcomeres (cell length and width area increased)
Volume overload
Characterized by:
- Concentric hypertrophy of LV
- Reduced cavity diameter
- Predominant deposition of sarcomeres is parallel to long axes of cells (cross-sectional area of myocytes is expanded but cell length is not)
Pressure overload
Increased mass + normal wall thickness
Volume overload
Increased mass + thickened left ventricular wall
Pressure overload
What are the neuro hormonal systems activated in CHF (3)
- NE/Epi
- RAAS activation
- Atrial natriuretic peptide release
Effects of NE/Epi (compensatory mechanism of CHF) (3)
Increased:
- HR
- Contraction
- Vascular resistance
Effects of RAAS activation (compensatory mechanism of CHF)
In chronological order: increased
- Tubular reabsorption of sodium and water
- Blood volume
- Venous return
- Preload
- Force of contraction
–> augments CO
Effects of atrial natriuretic peptide release (compensatory mechanism of CHF)
Increased tubular reabsorption of sodium and water
Basis for myocardial contractile failure (4)
- Death of myocytes, loss of vital elements
- Overworked and fatigued cardiac muscles
- Altered gene expression (due to prolonged hemodynamics overload)
- Re-expression of protein synthesis analogous to that in fetal cardiac development
What are huge early mediators of hypertrophy? (4)
- c-fos
- c-myc
- c-jun
- EGR1
Describe pathologic hypertrophy (4)
- Increased protein synthesis
- Induction of fetal gene program
- Synthesis of abnormal contractile protein isoforms that reduce excitation-coupling
- Fibrosis, reduced vasculature
Cardiac dysfunction is characterized by (3)
- Heart failure
- Arrhythmias
- Neurohumoral stimulation
What are the FUNCTIONAL modifications that follow neurohumoral stimulation in heart failure (4)
- Increased inotropy
- Increased HR
- Vasoconstriction
- Salt and water retention
What are the STRUCTURAL modifications that follow neurohumoral stimulation in heart failure (3)
- Hypertrophy
- Increased nonmuscular tissue
- Increased expression of adult cardiac genes
Mechanisms of Cardiac Dysfunction (5)
- Pump failure
- Obstruction to flow
- Regurgitant flow
- Disorders of cardiac conduction
- Shunt anomalies (Disruption of normal circulatory continuity)
Pump failure is exemplified by?
Acute MI
Obstruction to flow is exemplified by?
Aortic valve stenosis
Regurgitant flow is exemplified by?
Aortic regurgitation
Disorders of cardiac conduction is exemplified by?
Arrhythmias
Shunt anomalies are exemplified by? (2)
Infarct
Ischemia
In this mechanism of a cardiac dysfunction:
(+) necrosis/death of heart muscle –> cannot pump blood/failure to contract –> affect stroke volume
Pump blood
In this mechanism of a cardiac dysfunction:
- Aortic valve is calcified and stenosic, (+) LV Outflow
- Size and aperture of aortic valve is significantly reduced –> reduced blood flow
Obstruction to flow
In this mechanism of a cardiac dysfunction:
- There is increased back flow of blood into LV chamber –> greater volume of blood retaine in LV chamber
- Problem is volume overload
- It is seen in valvular dilatation or insufficiency
Regurgitant flow
In this mechanism of a cardiac dysfunction:
1. (+) opening between ventricular chambers –> free communication between chambers –> disruption of normal circulatory function –> CHF
Disruption of normal circulatory continuity/Shunt Anomalies
Etiology of CHF (8)
- Myocardial dysfunction
- Ventricular overload
- Restrictive disease
- Electrical disorders
- Iatrogenic
- Conduction system failure
- Valvular failure
- Cardiac malformations
What is the most common final pathway of many cardiac diseases?
CHF
What is the mechanism behind myocardial dysfunction?
Direct impairment of myocardial contractility
What is the mechanism behind ventricular overload?
Excessive pressure or volume, or high output states
What is the mechanism behind restrictive disease?
Reduced myocardial expansion
What is the mechanism behind electrical disorders?
Disrupted electrical function
What is the mechanism behind conduction system failure?
Electrical conduction dysfunction
What is the mechanism behind valvular failure? (3)
Inflammation
Degenerative
Congenital
What is the mechanism behind cardiac malformations?
Congenital
The ff are examples of which etiology of CHF?
- Ischemic heart disease
- Dilated cardiomyopathy
Myocardial dysfunction
The ff are examples of which etiology of CHF? (Pressure) 1. HPN 2. Aortic stenosis 3. Pulmonary embolism 4. Cor pulmonale
(Volume)
- Aortic regurgitation
- Mitral regurgitation
(High output states)
- Pregnancy
- Anemia
- Thyrotoxicosis
Ventricular overload
The ff are examples of which etiology of CHF? (Myocardial) 1. Restrictive/Ischemic cardiomyopathy 2. Amyloidosis 3. Myocarditis
(Pericardial)
- Pericarditis
- Tamponade
Restrictive disease
The ff are examples of which etiology of CHF?
- Pathological tachycardia
- Heart block
Electrical disorders
The ff are examples of which etiology of CHF?
1. Radiation
(Drugs)
- Doxyrubucin
- Cocaine
Iatrogenic
The ff are examples of which etiology of CHF?
- Acute MI
- Arrhythmia
Conduction system failure
The ff are examples of which etiology of CHF?
- Endocarditis
- RHD
- Calcific aortic stenosis
- Pulmonary stenosis
- Tricuspid atresia
Valvular failure
The ff are examples of which etiology of CHF?
- VSD
- ASD
- PDA
- TOF
- Coarctation of aorta
Cardiac malformations
What are the most frequent clinical conditions associated with CHF? (2)
- MI
2. Valvular disease
Types of CHF is categorized as to what? (3)
- Systolic or diastolic dysfunction
- Anatomic location
- High output failure or low output failure
What is the main pathology in systolic dysfunction?
Problem during contraction
The ff are examples of which type of CHF?
- IHD
- Hypertensive Heart Disease (HHD)
- Dilated Cardiomyopathy (D-CMP)
Systolic dysfunction
Most systolic dysfunction affects which chamber of the heart?
Left ventricle
It is the most common cause of heart failure
Systolic dysfunction
This type of CHF produces a forward type of failure
Systolic dysfunction
This type has the s/sx of pulmonary congestion and edema
Explanation:
- Blood dammed into lungs d/t love force of contraction –> pulmonary edema and congestion
- Blood tends to be dammed into left ventricle –> volume overload reflected in left atrium and pulmonary vasculature
Systolic dysfunction
What is the Pathophysiology of systolic dysfunction?
Progressive degeneration of myocardial contractile function
Main pathology in diastolic dysfunction
Inability of heart muscle to relax/reduced ventricular compliance
Explanation:
Blood volume contributes to preload, which enhances myocardial contractility. Since heart ms cannot relax, heart becomes stiff thereby decreasing preload –> affects:
1. Ejection fraction
2. CO (relatively preserved at rest but LV is stiff so heart is unable to increase its output in response to metabolic demands of peripheral tissues)
3. SV
This type of CHF is seen in:
- Massive LVH
- Amyloidosis
- Constrictive pericarditis
- Myocardial fibrosis
Diastolic dysfunction
Explanation:
Heart is stiff + reduced diameter –> reduced. Look volume in ventricular cavity
Which organ is immediately affected in left sided heart failure due to its proximity?
Lungs
Explanation:
Because LV a cannot expand, any increase in filling pressure is immediately referred back to pulmonary circulation –> rapid onset of pulmonary edema (“flash pulmonary edema”)
Aside from the lungs, left sided heart failure affects (2) other organs
- Kidneys (reduced renal blood flow)
Explanation: decreased CO –> reduced renal perfusion –> activation of RAAS –> induces salt and water retention! expansion of interstitial and intra vascular fluid volumes (increased blood volume, edema) - Brain (hypoxic encephalopathy)
This can progress to stupor and coma
Clinical features of left sided heart failure (5)
- Pulmonary symptoms (dyspnea, blood tinged sputum, elevated pulmonary wedge pressure, rales, cough)
- Increased HR, cardiomegaly
- Cyanosis
- Hypoxic encephalopathy
- Edema
This type of CHF is characterized by RV hypertrophy/dilatation with associated RA dilatation
Right sided heart failure
What are the causes right sided heart failure? (5)
- Pulmonary embolism
- Intrinsic lung disease (COPD, cystic fibrosis)
- Kyphoscoliosis
- Pneumoconiosis
- Schistosomiasis
Mechanism behind right sided heart failure
Increased pulmonary vascular resistance (d/t increased pulmonary vascular resistance and/or hypoxic vascular response)
What is the classical feature of right sided heart failure?
Nutmeg liver (due to chronic passive congestion)
The ff morphological characteristics can be seen in which type of CHF?
- Congestive hepatomegaly, centrilobular necrosis, sclerosis, NUTMEG LIVER
- Congestive splenomegaly
- Right ventricular dilatation/hypertrophy
- Congestion (kidneys)
- Hypoxic encephalopathy
Right sided heart failure
The ff are clinical features of which type of CHF?
- Splanchnic congestion (hepatosplenomegaly)
- Increased hepatojugular reflex or jugular venous distention (d/t increased pressure in RV and RA)
- Dependent edema (d/t increased venous hydrostatic pressure)
- Transudative effusions (ascitis, pleural effusion)
- Cyanosis
Right sided heart failure
Type of CHF:
- Heart failure secondary to pumping excessive volume of blood
- Causes anemia, hyperthyroidism, high fever, shunts between an artery and a vein
High output failure
Type of CHF:
- Secondary to ischemic heart disease, HPN, dilated cardiomyopathy, vulvar/pericardial disease
- The more common type of heart failure
Low output heart failure
A group of related heart disorders resulting from an imbalance between the blood supply to the heart (perfusion) and it’s demand for oxygen –> myocardial ischemia
IHD
- This brings about an insufficiency of oxygen
2. Reduces the availability of nutrients and removal of metabolites
Ischemia
(4) syndromes of IHD
- Acute myocardial infarction
- Angina pectoris
- Chronic IHD with heart failure
- Sudden cardiac death
IHD is also known as (2)
- CAD
2. CHD
This condition is the most important form of IHD wherein ischemia causes the death of heart muscle
Acute myocardial infarction
In this condition, ischemia is of insufficient severity to cause infarction but may be a precursor of MI
Angina pectoris
The central unifying problem of the 4 syndromes of IHD
Reduction/insufficient coronary blood flow
Non-modifiable risk factors in IHD (3)
- Age
- Gender (males > females)
- Familial disposition
Modifiable risk factors in IHD (4)
- Diet/Hyperlipidemia
Lipids deposited in coronary arteries - HPN
Associated with LVH - DM
Alteration in lipids, carbs, Peripheral vascular disease, Hyperlipidemia - Cigarette smoking
Carcinogenic; byproducts toxic to endothelium which could lead to development of atheroma or thrombus
Folic acid and other B vitamins break down what?
Homocysteine:
Increased levels may promote atherosclerosis by damaging inner lining of arteries and promoting blood clots
Inflammatory mediators in IHD (3) that cause endothelial injury
Increased
- C-reactive protein
- Ferritin
- Leukocyte count
Thrombotic mediators in IHD (2) that increase risk for thrombus formation
- Increased fibrinogen
2. Inherited polymorphism
Other lipids that are risk factors in IHD (2) (abnormal lipid metabolism)
- Genetic variation in Lipoprotein (LPA) gene region
2. ApoE polymorphism
A risk factor in IHD that inhibits LDL oxidation
Antioxidants
A risk factor in IHD that is a drug with antioxidant properties
Resveratrol
Pathogenesis of IHD
Decreased/Insufficient coronary perfusion relative to myocardial demand
In the Pathogenesis of IHD, there is decreased/Insufficient coronary perfusion relative to myocardial demand due to (4)
- Fixed stenosing atherosclerosis
- Fissure, break, rupture, ulceration, hemorrhage
- Coronary artery thrombosis
- Coronary artery vasoconstriction/vasospasm
What is the critical level of stenosis in fixed stenosing atherosclerosis?
70% - at this fixed level of obstruction, compensatory coronary artery vasodilation is insufficient to my moderate increases in myocardial oxygen demand leading to ischemia
What is Fixed Coronary Atherosclerosis?
Coronary artery with stable atheroma, no acute plaque change
It is the underlying cause of angina pectoris
Fixed Coronary Atherosclerosis
Most involved vessels in Fixed Coronary Atherosclerosis (3)
- LAD
- LCX
- RCS
Acute plaque change is associated with acute coronary syndromes (3)
- Unstable angina
- Acute MI
- Sudden cardiac death
What follows acute plaque change in IHD?
Thrombosis leading to complete obstruction
Occlusive thrombus is associated with?
Acute transmural myocardial infarction
Partial occlusive thrombus is subendocardial infarction is associated with? (2)
- Unstable angina
2. Sudden cardiac death
Non-atheromatous coronary arterial occlusive happen in <10% of cases (6)
- Embolism
- Dissecting aneurysm
- Vasospasm
- Congenital anomaly
- Trauma
Inflammation causes coronary obstruction (minority of cases wherein preexisting coronary artery vasculitis causes IHD), what is the initial lesion?
Interaction between endothelial cells and circulating leukocytes
What is the role of vasoconstriciton in IHD?
Reduction in lumen size –> increase in local mechanical forces —> increase risk of plaque rupture
- Paroxysmal, recurrent substernal/precordial chest pains
2. Caused by transient (15s-15min) myocardial ischemia that falls short in inducing an infarction
Angina pectoris
It is increased myocardial demand and decreased myocardial perfusion secondary to:
- Chronic stenosing coronary atherosclerosis
- Disrupted atherosclerotic plaque
- Vasospasm
- Thrombosis
- Coronary artery embolism
Angina pectoris
What are the (3) types of angina pectoris?
- Stable/Typical AP
- Prinzmetal/Variant AP
- Unstable/Crescendo AP
- Most common form of AP
- Caused by reduction of perfusion (in chronic stenosing coronary artery atherosclerosis)
- Transient, precipitated by exertion or emotion
- Relieved by rest and vasodilators
Stable/Typical AP
Type of AP with:
- Uncommon pattern of episodic angina occurring at rest (unrelated to activity, HR, BP)
- Caused by coronary VASOSPASM
- ECG changes suggestive of transmural ischemia (ST segment elevation)
- Responded promptly to vasodilators (nitroglycerin) and CCB
Prinzmetal/Variant AP
Type of AP:
- Occurs in 90% vessel block
- Caused by disruption of atherosclerotic plaque with superimposed partial/mural thrombosis, embolization, vasospasm
- Often occurs at rest
- Precursor to subsequent acute MI (hence called pre-infarction/Q-wave angina)
Unstable/Crescendo AP
This type of AP has a localized area of cardiac muscle necrosis due to ischemia
Acute MI
The ff are risk factors of which syndrome of IHD? (Major) 1. HPN 2. Cigarette smoking 3. DM 4. Hyperlipidemia
(Minor)
- Obesity
- Sex
- Age
- Stress
- Physical activity
Acute MI
Pathogenesis of acute MI (6)
- Coronary artery occlusion
- Increased myocardial demand (hypertrophy, tachycardia)
- Hemodynamic compromise (Hypotension)
- Vasospasm
- Emboli
- Unexplained (vasculitis, hematologist abnormalities, cardiac surgery)
Sequence of coronary artery thrombosis (4)
- Disruption of atheromatous plaque
- Subendothelial collagen exposed
- Extrinsic coagulation pathway activation
- Occlusive thrombus forms
Biochemical changes in AMI (3)
- Anaerobic glycolysis
(aerobic mechanisms cease in ischemia) - Decreased in high energy phosphates
(ATP, creatinine phosphates) - Lactic acidosis
(accumulation of break down products)
Reversible ultrastructural changes in AMI (4)
- Mitochondrial swelling
- Myofibrillar relaxation
- Glycogen depletion
- Sarcolemmal membrane damage
The predominant mechanism in myocardial function damage (1)
Coagulation necrosis
Region first affected by myocardial function damage
Subendocardial region with wavefront progression –> transmural (wall) thickness of ischemic zone
Pathologic forms of AMI (2)
- Transmural infarction
2. Subendocardial infarction
Type of AMI:
- Its necrosis involves full/nearly full thickness of the myocardium
- Aka ST elevation infarcts
- It’s associated with: chronic atherosclerotic obstruction, acute opaque change, superimposed complete thrombosis
- Heart appears dark and mottled in its early stages
Transmural infarction
Type of AMI:
- Necrosis is limited to inner 1/3 or 1/2 of ventricle
- Aka Non-ST elevation infarct
- Associated with: diffuse stenosing coronary artery atherosclerosis WITHOUT thrombosis and acute plaque change, partially obstructing coronary artery
Subendocardial infarction
What stain is suede for early recognition of AMI?
Triphenyl tetra-zolium chloride
- Normal: stains magenta red
- Infarcted: unstained/pale area
What is the hallmark of AMI (gross)?
Coagulation necrosis of myocardium
Gross features of AMI that happen in the indicated time:
- 30mins aft infarct
- 4-12hours after
- 18-24hours after
- 6weeks after
- No manifestation at gross level
- Gross changes are evident
- Pale to cyanotic
- Pale, fibrous scar
Microscopic features of AMI in the indicated times:
- Within 1 hour
- At 12-17 hours
- 3-7 days
- 7-10 days
- Intracellular edema, wavy fibers at periphery
- Neutrophilic infiltration, myocyte coagulation necrosis, dead myocytes are hypereosinophilic with loss of nuclei
- Disintegration of dead myofibers
- Fibrous scar
Factors affecting severity of AMI (6)
- Location
- Severity of obstruction
- Rate of development of occlusion
- Duration of occlusion
- Extent of collateral vessels
- Metabolic demands of myocardium
Sequence of changes in AMI (gross, prominent findings) (5)
- No gross change
- Vague pallor, softening
- Yellow pallor
- Central pallor with red border
- White firm scar
Sequence of changes in AMI (microscopic, prominent findings) (5)
- Waxy myocyte fibers
- Coagulation necrosis
- Neutrophilic infiltrate, then macrophages
- Granulation tissue
- Fibrotic scar
Gross features of AMI 1-10 days post infarct:
- Day 1-3
- Day 3-7
- Day 7-10
- Day 1-3: mottling with yellow-tan infarct center
- Day 3-7: hyperemic border, central yellow-tan softening
- Day 7-10: maximally yellow-tan and soft, depressed
red-tan margins
Light microscopic features of AMI 1-10 days post infarct:
- Day 1-3
- Day 3-7
- Day 7-10
- Day 1-3: coagulation necrosis, loss of nuclei and striations, interstitial neutrophilic infiltrates
- Day 3-7: start of disintegration of dead myofibers, dying neutrophils, early phagocytosis of dead cells by macrophages at infarct border
- Day 7-10: well developed phagocytosis of dead cells, early formation of fibrovascular granulation tissue at margin
Gross features of AMI day 10 onwards post infarct:
- 10-14 days
- 2-8 weeks
- > 2 months
- 10-14 days: red-gray depressed infarct borders
- 2-8 weeks: gray-whit scar
- > 2 months: complete scarring
Microscopic features of AMI day 10 onwards post infarct:
- 10-14 days
- 2-8 weeks
- > 2 months
- 10-14 days: well established granulation tissue with new blood vessels and collagen deposition
- 2-8 weeks: increased collagen deposition, decreased cellularity
- > 2 months: dense collagenous scar
- The best way to rescue myocardial ischemic myocardium
2. It may completely prevent necrosis
Reperfusion
How is AMI diagnosed (using what)? (3)
- Clinical symptoms
- Presence of myocardial proteins (tropomyosin, Troponin) in plasma
- ECG changes
S/Sx of AMI (3)
- Rapid, weak pulse
- Diaphoresis
- Dyspnea –> pulmonary congestion and edema
ECG feature in AMI
New Q waves
Serum markers of AMI (3)
- CK-MB (creatinine kinase enzymes)
- Troponin I and T
- LDH
Complications of MI (9)
- Contractile dysfunction
- Arrhythmias
- Right ventricular infarction
- Mural thrombus, embolism
- Ventricular aneurysms
- Pericarditis
- Rupture
- Infarct extension
- Infarct expansion
The complications and prognosis of MI is dependent on (3) things:
- Infarct size
- Location
- Factional thickness of damaged myocardial wall
This type of infarct has a higher probability of cardiogenic shock, arrhythmias, late CHF
Large transmural infarcts
This type of infarct has greater risk of free wall rupture, expansion, mural thrombi, aneurysm
Anterior transmural infarct
This type of infarct is more likely to be complicated by conduction blocks, right ventricular involvement, or both
Posterior transmural infarct
Which has a worse clinical course, anterior or posterior/inferior infarcts?
Anterior
Treatment of AMI (5)
- Thrombolysis
- Angioplasty
- Stent
- Coronary bypass surgery
- Altered morphology
- It is also known as ischemic cardiomyopathy
- Constitutes post-infarction cardiac decompensation (owing to exhaustion of compensatory hypertrophy of noninfarcted viable myocardium)
Chronic IHD
The ff are gross features of which syndrome of IHD?
- Hypertrophy (enlarged and heavy) secondary to LVH and dilatation
- Moderate to severe stenosing atherosclerosis, sometimes total occlusion
- Mural endocardium have patchy fibrous thickening
- Mural thrombi may be present
Chronic IHD
The ff are microscopic features of which syndrome of IHD?
- Interstitial fibrosis (Discrete gray-white scars) of healed infarcts
- Myocardial hypertrophy
- Diffuse subendocardial vacuolization
- Mural endocardium: patchy fibrous thickening, mural thrombi may be present
Chronic IHD
- Unexpected death in asymptomatic patients
- IHD –> fatal arrhythmia/massive pump failure –> cardiogenic shock –> ____
- It’s most common trigger is ACUTE MYOCARDIAL ISHEMIA
Sudden cardiac death
Th ff are a causes of which syndrome of IHD?
1. Atherosclerosis (major)
The ff occur in 10-20% of cases only)
- Congenital structure or coronary arterial abnormalities
- Aortic valve stenosis
- Mitral valve prolapse
- Dilated or hypertrophic cardiomyopathy
- Myocarditis
- Pulmonary HPN
- Hereditary or acquired abnormality of a cardiac conduction system
- Isolated hypertrophy
Sudden cardiac death
What is ultimate mechanism of SCD?
Lethal arrhythmia
The ff are consistent morphological findings in which syndrome of IHD?
- 80-90% of cases: marked coronary atherosclerosis
- 50%: acute plaque disruption
- 40%: healed or old MI
- 25%: acute MI changes
SCD
Most SCD is not associated with AMI but is a result of?
Myocardial ischemia (induced irritability that initiates mal If ant ventricular arrhythmias)
What gross and microscopic findings are indicative of severe chronic ischemia? (2)
- Scars of previous infarcts
2. Subendocardial myocyte vacuolization
What markedly improves the prognosis of patients vulnerable to SCD?
Implantation of pacemaker or automated cardioverter defibrillator (senses and electrically counteracts an episode of ventricular fibrillation)