Cardiac Pathology 1 Flashcards
What are the major branches that feed the heart?
Left anterior descending artery
Left circumflex artery
Right coronary artery
What artery does the left descending artery and left circumflex artery arise from?
Left coronary artery
Which artery is the most common site of critical stenosis?
Left anterior descending artery
What is the most common dominant heart?
Right dominant
Right coronary artery supplies posterior aspect of the heart
What supplies a codominant heart?
Left circumflex artery
Right coronary artery
What happens to compliance and elasticity as we age?
Decreased compliance Decreased elasticity (due to increased collagen)
Fibrosis of the mitral valve causes what?
Buckling into left atrium -> atrial dilation -> atrial fibrillation
Calcification of the aortic valve leads to what?
Aortic stenosis -> increased left ventricular pressure -> hypertrophy -> heart failure
What is lambl’s excrescences?
Filiform fronds that occur at sites of valvular closure
How do Lambl’s excrescences form?
Small thrombi which form from minor endothelial damage due to wear and tear
What cavity decreases size in the aging heart?
Left ventricle (usually due to HTN)
What cavity increases in size with the aging heart?
Atrial dilation (due to fibrous mitral valve)
Atherosclerosis affecting the vasa vasorum causes what?
Predisposition to dissection
What are epicardial and myocardial changes seen in the aging heart?
Increased epicardial fat Lipofuscin accumulates Basophilic degeneration Myocyte loss Amyloid deposition
What is the function of epicardial fat?
Mechanically cushion cardiac vessels during myocardial contraction
What is lipofuscin?
Yellow-brown pigment which is a product of intracellular catabolism and oxidant stress
Where does lipofuscin accumulate?
Liver
Kidney
Ganglion cells
Heart
What is transthyretin?
Normal serum protein that binds and transports thyroxine
What is senile cardiac amyloidosis?
Amyloid deposition that causes stiffness and thickening of the walls leading to SOB, exercise intolerance, and heart failure
What is pump failure?
Insufficient contraction during systole to push blood into circulation
OR
Insufficient filling of blood into the heart during diastole
What does flow obstruction cause?
Increase the resistance pressure that the heart has to push against (valve stenosis, HTN)
Ischemic myocyte loss (atherosclerosis, cardiac ischemia)
What is valvular regurgitation?
Valve is incompetent
What can valvular regurgitation cause?
Volume overload of previous heart chamber
Dilating the heart
Decreasing its ability to adequately pump
What is shunted blood flow?
Blood flows between two structures which are not commonly connected
When is shunting of blood seen?
VSD
PDA
After MI
What is the most common cause of death in the first 24 hours after infarction?
Arrhythmias
How does ischemic injury cause arrhythmias?
Ischemic injury -> cardiac remodeling -> increased fibrosis -> dilated cardiac dysfunction -> arrhythmias
When does traumatic aortic dissection frequently occur?
MVC
What happens with aortic dissection due to MVC?
Rapid deceleration forces causes blow to the chest as the steering wheel impacts the driver -> traumatic separation of ligmentum arteriosum from aorta
When does abnormal dilation of a heart chamber occur?
Volume overload
When does hypertrophy occur?
Increase in pressure
Increased pressure causes what type of hypertrophy?
Concentric
Increased volume causes what type of hypertrophy?
Eccentric
In dilated hearts how is hypertrophy measured?
Heart weight
What happens to myocytes in concentric hypertrophy?
Increase in size or diameter of myocytes
What happens to myocytes in eccentric hypertrophy?
Increase in length
What causes left ventricular hypertrophy?
Chronic HTN
Aortic valvular stenosis
Overload of what causes cardiac dysfunction and heart failure?
Pressure
Volume
Is there an increase in capillary number with pathologic hypertrophy?
No
Is there an increase in capillary number in exercise induced hypertrophy?
Yes
Why does hypertrophy lead to ischemic decompensation
No additional capillaries but increased oxygen required
What happens with increased activity of the neurohumoral system?
Norepinephrine increases contractility in an attempt to maintain systemic perfusion but ultimately the increase in heart rate and contractility can’t keep up with peripheral demand
What is the most common endpoint for cardiovascular disease?
Congestive heart failure
What is diastolic congestive heart failure?
Blood does not adequately fill the ventricle causing less blood to pump into circulation
When does diastolic congestive heart failure occur?
Ventricles are too thick or stiff
What is systolic congestive heart failure?
Inadequate contractile strength to pump an adequate amount of blood out of the heart
When does systolic congestive heart failure occur?
Dilated cardiac dysfunction
Which heart failure has decreased ejection fraction?
Systolic
What is ejection fraction?
Total amount of blood ejected from the heart
Why doesn’t the heart pump well in systolic congestive heart failure?
Ischemic injury removes cardiomyocytes
Ventricles are too dilated to pump well (dilated cardiac dysfunction)
Valve regurgitation distends the pump causes it to be ineffective
Which heart failure has normal ejection fraction?
Diastolic
What leads to diastolic dysfunction?
HTN Aortic stenosis Hypertrophic cardiomyopathy Fibrosis Restrictive cardiomyopathy
What can causes myocardial fibrosis?
Radiation therapy
Amyloid deposition
What is the pathophysiology of left heart failure?
Heart unable to pump blood from the left ventricle to the systemic circulation results in backup of fluid into the pulmonary circulation and lungs
Decreased cardiac output and tissue perfusion (forward failure)
Pooling of blood backward (backward failure)
What are the main causes of left heart failure?
Myocardial ischemia
HTN
Left-sided valve disease
Myocardial disease
What are the symptoms of left sided heart failure?
Pulmonary congestion/edema Cough Dyspnea SOB Wheezing Crackles in lungs Cough Orthopnea (dyspnea when laying flat)
What is paroxysmal nocturnal dyspnea?
Dyspnea at night awaking them from sleep
Why does paroxysmal nocturnal dyspnea occur?
Respiratory and cough center response is blunted during sleep (feels like they are suffocating)
Impaired left ventricular function in left heart failure can cause what?
Atrial dilation leads to atrial fibrillation
Loss of atrial function in atrial dilation and atrial fibrillation leads to what?
Pump failure
Lack of perfusion to the brain in left heart failure leads to what?
Restlessness
Confusion
Ischemic cerebral injury
Coma
Lack of perfusion to the kidneys in left heart failure leads to what?
Azotemia
Increased creatinine
Increased BUN
What edema is seen with left heart failure?
Perivascular
Interstital edema
What is seen on CXR with left heart failure?
Kerley B lines
What are Kerley B lines?
Short parallel lines that reach the lung periphery
Manifestation of interstitial pulmonary edema (specifically interlobular septa)
What other conditions are Kerley B lines seen in?
Lymphangitis carcinomatosis
Lymphoma
Pneumonia
What do RBCs do in left heart failure?
Extravasate into edema within alveolar spaces
What are the histologic signs of heart failure?
Hermosiderin-laden macrophages (due to extravasated RBCs)
What is the most common cause of right heart failure?
Left heart failure
Why does left heart failure cause right heart failure?
Backpooling of blood from the left heart into the pulmonary vasculature which increases the pressure gradient that the right ventricle has to pump against
Where does the blood pool up in right heart failure?
Right atrium
Venous system
What happens to the liver in right heart failure?
Impaired hepatic venous draining leading to stasis of blood in the hepatic parenchyma and hepatomegaly
What happens to the spleen in right heart failure?
Impaired splenic vein draining
Peritoneal, pleural, and pericardial effusions develop in what type of heart failure?
Right heart failure
Why does peritoneal, pleural, and pericardial effusions develop in right heart failure?
Intravascular pressure is high, displacing fluid into mesothelial lined body cavities
Marked weight gain is seen in which type of heart failure?
Right heart failure
What is the pathophysiology of isolated right sided heart failure?
With pulmonary HTN the right ventricle pushes against an increased pressure gradient, when the pressure is more than the pump can counter the right heart fails and fluid backs up into venous circulation
What is cor pulmonale?
Isolated right-sided heart failure
What are three causes of pulmonary HTN that can leads to isolated right heart failure?
1) Parenchymal lung disease
2) Lung thromboemboli
3) Primary pulmonary hypertension
Liver and splenic congestion leads to what in right heart failure?
Hepatosplenomegaly
What are the symptoms of right heart failure?
Distended jugular veins Effusions Edema (gravity dependent) Weight gain Ascites Fatigue Exertional dyspnsea
Nutmeg liver is common what type of heart failure?
Right sided heart failure
What liver hemorrhage is seen with right sided heart failure?
Centrilobular hemorrhage and necrosis
What is emphysema?
Chronic pulmonary parenchymal disease
Emphysema causes what cardiac conditions?
Pulmonary HTN
Right heart failure
What does the heart look like with cor pulmonale?
Hypertrophy of right ventricle
Normal left ventricle
Thromboemboli from DVTs can also cause what type of heart failure?
Right heart failure
What is acute cor pulmonale typically attributable to?
Large thromboembolus
Multiple thromboemboli in the pulmonary trunk
Thromboemboli in addition to right heart failure causes what?
Concomitant decreased systemic and coronary perfusion
What does the majority of congenital heart diseases arise from?
Faulty embryogenesis due to sporadic genetic abnormalities
Fetal alcohol syndrome causes what heart defect?
Septal defects
What is the most common cardiac abnormality?
VSD
What is the most common genetic cause of congenital heart disease?
Trisomy 21 (Down Syndrome)
What symptoms do patients with Down Syndrome have?
Epicanthic folds Flat facial profile Simian crease Mental retardation Abundant neck skin Intestinal stenosis Umbilical hernia Predisposition to leukemia Hypotonia
What is the most common heart defect with trisomy 21?
VSD
What heart defects are common with Marfan syndrome?
Aortic aneurysm
Aortic dissection
Mitral valve prolapse
Aortic valve prolapse
DiGeorge syndrome is caused by a deletion in which chromosome?
22
What is the CATCH-22 acronym?
Cardiac abnormality Abnormal facies Thymic aplasia Cleft palate Hypocalcemia
What cardiac abnormality is associated with DiGeorge syndrome?
Conotruncal abnormalities
Conotruncal abnormalities occur in which heart field?
2nd
What are the conotruncal abnormalities?
Tetralogy of fallot
Transposition of great arteries
Turner syndrome is associated with which cardiac abnormality?
Coarctation of the aorta
Trisomy 13 (Patau syndrome) is associated with which cardiac abnormalities?
PDA
Septal defects
Trisomy 18 (Edward’s syndrome) is associated with which cardiac abnormalities?
PDA
Septal defects
What are the two categories of shunts?
Left-to-right shunts
Right-to-left shunts
Which side of the heart has higher pressure?
Left side
What are the symptoms of left to right shunts?
Asymptomatic
What are the symptoms of right to left shunts?
Hypoxemia
Cyanosis
What does chronic hypoxemia cause?
Polycythemia
What is hypertrophic osteoarthropathy?
Inflammation of the periosteum of the connective tissue surrounding bone
What causes hypertrophic osteoarthropathy?
Long standing cyanosis
What shunt causing clubbing of tips of finger and toes?
Right-to-left
What are the left-to-right shunts?
ASD
VSD
PDA
What are the right-to-left shunts?
Tetrology of Fallot Transposition of the Great Arteries Tricuspid atresia Truncus arteriosus Coarctation of the aorta with PDA
What is the pathophysiology behind hypertrophic osteoarthropathy?
Megakaryocyte fragments bypass the lungs and release bradykinin, TGF-Beta1, VEGF, and PDGF causing clubbing, periostitis
All left-to-right shunts cause what?
Pulmonary HTN as increased blood increases the pressure in the pulmonary trunk
ASD and VSD causes increase in which volumes?
Right ventricles
Pulmonary outflow
PDA causes increase in what volume?
Increase pulmonary blood flow
What happens in a paradoxical embolism?
Venous embolus crosses to the arterial side (need a defect in the heart or major vessels)
What are the types of emboli?
Thromboemboli
Septic emboli
Traumatic bone marrow emboli
Iatrogenic air emboli
What is the most common ASD?
Secundum (found in the center of the atrial septum)
What are the symptoms of ASD?
Usually asymptomatic (sometimes pulmonary HTN)
How are ASDs fixed?
Noninvasive endovascular approach
What are the two other common ASDs?
Primum anomaly (adjacent to AV valves) Sinus venosa (near entrance to SVC)
What is primum anomaly associated with?
AV valve abnormalities
VSD
What is sinus venosa defects associated with?
Anomalous pulmonary venous return
What murmur can be seen with ASDs?
Ejection systolic murmur
What is the most common congenital cardiac malformation?
VSD
Majority of VSDs involve what?
Membraneous interventricular septum
What are the other types of VSDs?
Subpulmonary (infundibular)
AV canal
Muscular
What are the symptoms of VSDs?
Asymptomatic except those associated with tetralogy of fallot
What murmur is seen with VSDs?
Holosystolic murmur
Do VSDs close spontaneously?
Yes
What are the symptoms of large VSDs?
Right ventricular hypertrophy
Pulmonary HTN
Shunt reversal -> cyanosis -> death
What is the Eisenmenger Syndrome?
Shunt reversal in a VSD
What pathway for Eisenmenger syndrome?
Long standing left to right shunt -> increased pulmonary blood flow -> endothelial dysfunction and pulmonary vascular remodeling -> increased in pulmonary vascular resistance -> inverted (right-to-left) shunt
Eisenmenger is associated with what?
Large VSDs
What is the endothelial damage done in Eisenmenger syndrome?
Arteriolar intimal proliferation
Medial hypertrophy
Capillary and arteriolar occlusion
Is endothelial damage in Eisenmenger syndrome reversible or irreversible?
Irreversible
What are the two natural shunts in the fetal circulation that bypass the lungs?
Foramen ovale
Ductus arteriosus
What does the foramen ovale connect?
Atria of the heart
What keeps the foramen ovale shut after birth?
Increased left sided heart pressure
What causes the patent foramen ovale to open?
Increased right heart pressure
Valsalva
Bowel movement
Coughing/sneezing
Opening of a patent foramen ovale causes what?
Right-to-left shunting
What is clinically significant about a patent foramen ovale?
Possible paradoxical embolus
What does the ductus arteriosus connect?
Pulmonary artery and aorta
When does the ductus arteriosus typically close?
2-3 days after birth
What causes the ductus arteriosus not to close?
Hypoxia
Increased vascular pressure
What murmur is heard with patent ductus arteriosus?
Harsh, continuous medium pitched murmur with machine-like quality
What is used to close a patent ductus arteriosus?
Indomethacin
What shunt occurs with patent ductus arteriosus?
Left-to-Right
What can happen with a large patent ductus arteriosus?
Increased pulmonary pressure
Shunt reversal -> Cyanosis
What is used to preserve the patency of ductus arteriosus in certain congenital malformation?
Prostaglandin E
What are the four features of tetralogy of fallot?
1) VSD
2) Right ventricular hypertrophy
3) Pulmonary valve stenosis
4) Overriding aorta
What is an overriding aorta?
Entrance to the aorta is centered at the VSD instead of the main part of the left ventricle
What causes the right ventricular hypertrophy in tetralogy of fallot?
Pressure overload induced by pulmonary stenosis
What dictates the clinical severity of Tetralogy of Fallot?
Degree of pulmonary stenosis
What is the most common cyanotic congenital heart disease?
Tetralogy of Fallot
What murmur is heard with tetralogy of fallot?
Holosystolic murmur and/or systolic ejection murmur
What does the holosystolic murmur depend on in tetralogy of fallot?
Degree of VSD
What does the systolic ejection murmur depend on in tetralogy of fallot?
Degree of pulmonary stenosis
Infants with what in tetralogy of fallot require immediate intervention?
Severe pulmonary stenosis
Is right ventricular outflow tract or pulmonic valve stenosis progressive in tetralogy of fallot?
Yes
What are “tet” spells
Significant obstruction of the pulmonary outflow tract triggered by increased demand such as during period of excitement, crying, feeding, or increased activity
What are the symptoms of “tet” spells?
Cyanosis
Syncope
Why do children squat during “tet” spells?
Increases peripheral vascular resistance which decreases the degree of right to left shunting (allows them to oxygenate better)
Does clubbing of the fingers occur with tetralogy of fallot?
Yes
What is seen on x-ray in a patient with tetralogy of fallot?
Boot shaped heart
What causes the boot shaped heart seen with tetralogy of fallot?
Upturned cardiac apex caused by right ventricular hypertrophy and a concave pulmonary arterial segment
What happens in the classic form of transposition of the great arteries?
Right ventricle is connected to the aorta
Left ventricle is connected to the pulmonary trunk
Is transposition of the great arteries compatible with life?
No
What is often kept open if a baby is born with transposition of the great arteries?
Ductus arteriosus with prostaglandin E1
Transposition of the great vessels results in what type of shunt?
Right-to-left
Which ventricle hypertrophies in the transposition of the great arteries?
Right ventricle
What are the symptoms associated with transposition of the great vessels?
Cyanosis
Trouble breathing
What is tricuspid atresia?
Absence of the tricuspid valve
Is tricuspid atresia compatible with life?
No (not without ASD or VSD)
What is the left ventricle responsible for in transposition of the great vessels?
Pumping blood to both the right ventricle, lungs, and systemic circulation
What is needed immediately after birth for tricuspid atresia?
Surgical correction
What is coarctation of the aorta?
Obstructive defect which manifests as focal narrowing of the aorta
Which gender is coarctation of the aorta most common in?
Males
If females are seen with coarctation of the aorta what syndrome should be suspected?
Turner’s syndrome
What is associated with half of the cases of coarctation of the aorta?
Bicuspid aortic valve
Patients with coarctation of the aorta have an increased risk of what?
Berry aneurysm which predisposes them to intracerebral hemorrhage
Infantile coarctation of the aorta is characterized by what?
Preductal coarctation (located before the ductus arteriosus) -> significantly less blood flow to the lower half of the body
Adult coarctation of the aorta is characterized by what?
Coarctation at the ductal arteriosus or in a postductal location
Diminished pulses is seen in which form of coarctation of the aorta?
Adult
Is there cyanosis with coarctation of the aorta?
Yes
What is seen on CXR with adult coarctation of the aorta?
Tortuous collateral intercostal vessels which cause pressure erosion of the inferior rib margins causing rib notching
What is the difference between the infantile and adult form of coarctation of the aorta?
Infantile form has a PDA
Adult for does NOT have a PDA
What does the clinical presentation of coarctation of the aorta depend on?
Severity of stenosis
What are the symptoms of the infantile form of coarctation of the aorta?
Cyanosis in lower extremities Absent lower extremity pulses Heart failure Shock Pale, irritable, diaphoretic, SOB
What are the symptoms of coarctation of the aorta without PDA?
Hypertension in upper extremities Hypotension in lower extremities Cold lower extremities Femoral artery pulse delay Pain in extremities with exercise
What hypertrophy is seen with coarctation of the aorta?
Concentric left ventricular hypertrophy (also heart failure)
Which valve dysfunctions can be see with aortic stenosis?
Hypoplastic (small)
Dysplastic (nodular thickened)
Abnormal cusp number
What hypertrophy is seen with aortic stenosis?
Concentric left ventricular hypertrophy (due to pressure overload)
What is hypoplastic left heart syndrome?
Aorta is stenotic or atretic and oxygenated blood flow is only possible through an atrial septal defect with a PDA
What is the blood flow in hypoplastic left heart syndrome?
Right ventricle -> lungs -> left atrium -> right heart (through ASD) -> right ventricle pumps blood to systemic (through PDA)
What hypertrophy is seen with pulmonary stenosis?
Right ventricular hypertrophy
What two complexes is pulmonary stenosis associated with?
Tetralogy of Fallot
Transposition of the Great Arteries
What are the causes of ischemic heart disease?
Atherosclerosis
Coronary artery emboli
Myocardial vessel inflammation (vasculitis)
Vessel spasm
What are the classic clinical features of myocardial infarction?
Prolonged (>30 minutes) Substernal chest pain "Crushing, stabbing, squeezing" Radiate to neck, shoulder or jaw Rapid, weak pulse Profuse sweating Nausea, vomiting Dyspnea and discomfort
Nausea and vomiting are related to what specific MI location?
Posterior-inferior (due to vagal stimulation)
Diabetic neuropathy may hide symptoms of what?
Myocardial infarction
How is myocardial infarction diagnosed?
Symptoms EKG changes Cardiac markers (troponin)
Myocardial ischemia leads to loss of function after how many minutes?
1-2 minutes
Necrosis occurs how long after myocardial infarction?
20-40 minutes
How long after a MI is neurologic recovery unlikely?
5-7 minutes
How long after a MI is severe irreversible brain damage probable?
10 minutes
What is cardioplegia?
Heart is cooled significantly lowering the myocytes metabolic rate and preventing ischemic death
Oxygen consumption of myocytes drops 50% for every how much reduction in temperature?
10 degrees celsius
After MI how long before onset fo ATP depletion?
Seconds
After MI how long before loss of contractility?
Less than 2 minutes
After MI how long before ATP reduced to 50% of normal?
10 minutes
After MI how long before ATP is reduced to 10% of normal?
40 minutes
After MI how long before irreversible cell injury?
20-40 minutes
After MI how long before microvascular injury?
1 hour
What are the most specific and sensitive markers we have for acute myocardial infarction?
Troponin T
Troponin I
What are the function of troponin T and I?
Regulate calcium mediated contraction of cardiac muscle
Which troponin is currently used by most labs?
Troponin I
Which creatine kinase isoform is present in cardiac muscle?
MB heterodimer
Which creatine kinase isoform is present in muscle?
MM
What creatine kinase isoform is present in the brain and lung?
BB
Is CK-MB sensitive?
Yes
Is CK-MB specific?
No
What is released by cardiac muscle with injury but is nonspecific?
Myoblobin
Are troponin I and T normally detected in circulation?
No
What releases troponin I and T
Dead and dying cardiomyocytes
When does dying cardiomyocytes start releasing troponin?
3 hours
Why are serial troponin draws necessary?
Patient could have a heart attack prior to an increase in troponin levels
When does CK-MB go back to baseline?
48-72 hours after infarction
How long is troponin elevated for?
5 days
CK-MB is specifically utilized to assess for what?
Reinfarction of the heart after initial heart attack
When does CK-MB and troponin I peak?
24 hours
What arteries are most commonly occluded in MI?
LAD > right coronary artery > left circumflex artery
Occlusion of the LAD causes infarction of what?
Apex
LV anterior wall
Posterior 2/3 of septum
Occlusion of the left circumflex artery causes infarction of what?
LV lateral wall
Occlusion of the right coronary artery causes infarction of what?
RV free wall
LV posterior wall
Posterior 1/2 of septum
When does a subendothelial infarct occur?
Reperfusion of transmural infarct (regional) Global hypotension (circumferential)
What happens with a reperfusion of transmural infarct?
Blocking thrombus is dislodge either spontaneously or through thrombolytic therapy -> regional subendocardial infarct
When does global hypotension occur?
Shock/significant coronary artery stenosis -> circumferential subendocardial infarct
What is a multifocal microinfarction?
Numerous small infarcts occur within the smaller intramural vessels of the myocardium
What causes a multifocal microinfarction?
Cocaine use
Embolic disease
How do coronary artery perfuse the heart muscle?
Epicardium -> endocardium
What is the last portion of the heart to get perfused?
Myocardium near the endocardial surface
How do infarctions spread?
Inside of the heart out (necrotic core expands into the overlying tissue)
What perfuses the endocardium?
Blood in the heart chamber (this portion of the heart still viable despite the infarction)
What does the rate of necrosis throughout the heart depend on with a MI?
Degrees of collateral circulation with areas being fed by a single vessel taking a shorter time to become a transmural infarct
What is seen on the electron microscope at 0 hours?
Relaxation of myofibrils
Glycogen loss
Mitochondrial swelling
What is seen on light microscope from 0.5-4 hours?
Waviness of fibers at border (due to sarcolemmal disruption)
What is seen on electron microscope from 0.5-4 hours?
Sarcolemmal disruption
Mitochondrial amorphous densities
What is seen grossly from 4-12 hours
Dark mottling
What is seen on light microscope from 4-12 hours?
Early coagulation necrosis
Edema
Hemorrhage
What is seen grossly from 12-24 hours?
Dark mottling
What is seen on light microscope from 12-24 hours
Ongoing coagulative necrosis Pyknosis of nuclei Myocyte hypereosinophila Marginal contraction band necrosis Early neurtrophilic infiltrate
What is pyknosis?
Condensation of the chromatin in the nucleus
What is seen grossly from 1-3 days?
Mottling with yellow-tan infarct center
What is seen on light microscope from 1-3 days?
Coagulation necrosis
Loss of nuclei and striations
Brisk interstital infiltrate of neutrophils
What is seen grossly from 3-7 days?
Hyperemic border
Central yellow-tan softening
What is seen on light microscope from 3-7 days?
Beginning disintegration of dead myofibers with dying neutrophils
Early phagocytosis of dead cells by macrophages at infarct border
What is seen grossly from 7-10 days?
Maximally yellow tan, and soft, with depressed red-tan margins
What is seen on light microscope from 7-10 days?
Well-developed phagocytosis of dead cells
Granulation tissue at margins
What is seen grossly from 10-14 days?
Red-gray depressed infarct borders
What is seen on light microscope from 10-14 days?
Well-established granulation tissue with new blood vessels and collagen deposition
What is seen grossly from 2-8 weeks?
Gray-white scar, progressive from border towards core of infarct
What is seen on light microscope from 2-8 weeks?
Increased collagen deposition
Decreased cellularity
What is seen grossly from 2 months?
Scarring complete
What is seen on light microscope from 2 months?
Dense collagenous scar
What is the first sign of irreversible injury in myocardial infarction?
Wavy fiber change
What causes the wavy fiber change after MI?
Mechanical pulling by viable fibers on dead fibers resulting in folding and twisting
What leaks out of dead myoctyes after 2-3 hours
Lactate dehydrogenase
What stain is used to identify lactate dehydrogenase after MI?
Triphenyltetrazolium chloride
Do areas of infarction hemorrhage or scar turn bright red with the triphenyltetrazolium choloride?
No
What happens cellularly with irreversible injury to myocytes?
Cell membrane disrupted with reperfusion
Influx of calcium causing sarcomeres to contract
Contraction bands on light microscopy (contraction band necrosis)
What replaces normal myocytes after MI?
Fibroblasts with increased collagen
What are early complications of MI?
Life threatening arrhythmia (v tach, v fib) Contractile dysfunction (shock)
What are intermediate complications of MI?
Rupture: septal, wall, papillary
Acute pericarditis
What are the late complications of MI?
Chronic pericarditis (Dressler syndrome) Ventricular aneurysm (remodeling) Continued risk of heart failure, life threatening arrhythmia
What causes mitral regurgitation after MI?
Ischemic papillary muscles
What is the most common mechanical complication of MI?
Papillary muscle rupture
Which infarct causes papillary muscle rupture?
Right circumflex artery
Which infarct causes ventricular septal rupture?
Anterior infarcts
What is the most common cause of death due to MI?
Fatal arrhythmias (v fib)
What is the second most common cause of death after MI?
Cardiogenic shock (pump failure due to contractile dysfunction due to the death of heart muscle)
When does myocaridal rupture typically occur after MI?
2-4 days
Myocardial rupture after MI requires what?
Transmural infarct
Rupture of the free wall can lead to what?
Blood accumulating in the pericardial space
What is blood accumulating in the pericardial space called?
Acute pericardial tamponade
What happens to the heart during acute pericardial tamponade?
Heart is unable to adequately fill during diastole because of the pressure of the blood in the pericardial sac
Septal rupture can lead to what?
VSD with left to right shunting
Papillary muscle rupture can lead to what?
Valve incompetence
Post infarct regurgitation
Why does myocardial rupture occur more often in the elderly?
Lower muscle mass
What is pericarditis?
Inflammation of the pericardium
What is present with acute pericarditis?
Pericardial friction rub
When does myocardial rupture and acute pericarditis occur post MI?
2-4 days
What are the risk factors for myocardial rupture?
Increased age
First MI
Absence of LV hypertrophy
Acute pericardial tamponade leads to what?
Hemodynamic collapse
When do late complications of MI occur?
After 2 weeks
What is Dressler syndrome?
Fibrinous pericarditis
What causes Dressler syndrome?
Immune response against myocardial proteins which are encountered by the immune system in the blood after a previous infarct
Anti-heart antibodies which create an inflammatory reaction involving the pericardium
What is the end result of Dressler syndrome?
Febrile pericarditis
Pericardial effusion
Pleuritic pain
What causes the late complication of ventricular aneurysm post MI?
Thin scarred ventricular wall
What causes progressive heart failure after MI?
Inadequate compensatory response
What is seen grossly with Dressler syndrome?
Dark, roughened epicardial surface
What is the definition of angina pectoris?
Transient, often recurrent chest pain induced by myocardial ischemia insufficient to induce myocardial infarction
What are the three types of angina pectoris?
1) Stable angina
2) Prinzmetal variant angina
3) Unstable angina
What is released due to lack of oxygen in the heart muscle?
Adenosine
Bradykinin
Which patients often have silent angina?
Elderly
Previous MI
Diabetic neuropathy
What is stable angina?
Demand type of ischemia in that with increased physical activity or stress the heart becomes ischemic but when the patient is at rest there is an adequate supply of oxygen
What causes stable angina?
Stenotic occlusion of coronary artery
What are the symptoms of stable angina?
Substernal pressure, squeezing, burning
What relieves stable angina?
Rest
Vasodilators
What induces stable angina?
Physical activity
Stress
What is prinzmetal variant angina?
Episodic coronary artery spasm
What makes prinzmetal variant angina worse?
Aterosclerotic disease
When does prinzmetal variant angina occur?
At rest
Is prinzmetal variant angina associated with physical activity?
No
What is the pattern of prinzmetal variant angina?
3-6 month clusters of recurrent attacks separated by asymptomatic periods
What is given to to alleviate the symptoms of prinzmetal variant angina?
Vasodilators (nitrate)
What is unstable angina?
Angina which is present at rest or angina that increases in frequency or duration
What is the most common cause of unstable angina with acute chest pain with activity and rest?
Rupture of atherosclerotic plaque which results in a non-occlusive thrombus
What causes unstable progresive angina?
Progressive obstruction
What type of pattern is there with unstable angina?
Crescendo patern
When is table angina symptomatic?
Only with increased demand for oxygen during exercise or activity
Unstable angina is due to what?
Problem with overall supply of oxygen even at rest
ST elevation on EKG corresponds with what?
Transmural infarction
When there isn’t a ST elevation on EKG what is on the differential?
NSTEMI
Unstable angina
What can be used to tell the difference between NSTEMI and unstable angina?
Presence of troponin
Is troponin elevated in NSTEMI?
Yes
Is troponin elevated in unstable angina?
No
Does unstable angina or NSTEMI show ST elevations?
No
