Lecture 2: Cardiac Pathology Part 1 (Hillard) Flashcards
How is Right vs Left dominance of the heart determined?
- whichever side the posterior descending artery originates from is the dominant side
Right Dominant: supplied by Right Coronary Artery (RCA in 70%)
Left Dominant: supplied by Left Circumflex Artery (LCX in 10%)
What are some common changes seen in the aging heart? (EF/LA/BD/ML/SA)
- inc. epicardial fat, lipofuscin accumulation (tan-brown), basophilic degeneration, myocyte loss
amyloid deposit of transthyretin –> senile amyloidosis (HEART FAILURE)
Cardiovascular Dysfunction
What are common reasons for Pump Failure, Flow Obstruction, and Regurgitant Flow?
PF: inadequate contraction (systole) or filling (diastole)
FO: inc. resistance (valve stenosis/HTN) or dec. blood flow (atherosclerosis –> cardiac ischemia)
RF: incompetent valves (vascular disease)
Cardiovascular Dysfunction
What are common reasons for Shunted Flow, Conduction Abnormalities, and Vessel Rupture?
How do motor vehicle collisions damage the aorta?
SF: congenital disease (VSD/PDA), after myocardial infarct –> ventricular septal rupture
CA: ischemic injury (infarct/nodal injury/dilated) or heritable arrhythmias
VR: aortic dissection or trauma (motor vehicle trauma)
- ligamentum arteriosum gets torn from aorta
- causes rapid, life-threatening hemorrhage
- 2nd most common cause of death in MVC
What is the best measure of heart hypertrophy?
WEIGHT
- hypertrophy = inc. muscle mass of thickened heart due to inc. cardiomyocyte size/length
- cardiomegaly = abnormal enlargement, which can have an increased weight/size; dilated hearts will appear larger but will not weight more simply because they are expanded
How do myocytes of the heart change when exposed to pressure overload vs volume overload?
Pressure Overload:
- concentric hypertrophy of ventricle
- sarcomeres added in parallel (thicken)
Volume Overload:
- dilation of ventricles
- sarcomeres added in series (lengthen)
What is Congestive Heart Failure and what are two common causes of disease?
- common, progressive condition caused by pump failure –> inadequate blood delivery (common end stage of many heart diseases)
- loss of ability to FILL the VENTRICLES during diastole (ventricle too stiff/thick) OR loss of myocardial CONTRACTILE function during systole (dilated/enlarged heart)
What are common causes of Systolic (3) and Diastolic (3) Dysfunction?
S: ischemic injury, dilated cardiomyopathy, valve regurg.
- DECREASED ejection fraction
D: HTN, aortic stenosis, hypertrophic/restrictive cardiomyopathy
- NORMAL ejection fraction, lower total volume
- also caused by fibrosis (radiation/amyloid)
What are 3 main causes of Left-sided Heart Failure and what does it cause clinically (Forward vs Backward Failure)?
causes: myocardial ischemia, HTN, left-sided valve disease
clinical:
- pulmonary congestion/edema (cough, crackles, wheezes = “backwards failure”)
- dec. tissue perfusion (cerebral, renal = azotemia: inc. creatinine and blood/urea nitrogen lvls = “forward failure”)
What is seen on chest x-ray of pts. with Left Heart Failure and what is a histological hallmark of heart failure?
X-Ray –> Kerley B lines
- not specific
- short, parallel lines that reach lung periphery
Histo: hemosiderin-laden macrophages
- “Heart Failure Cells”
- see brown macrophages in alveolar space of lungs
What is the most common cause of Right Heart Failure?
Left Heart Failure
- causes inc. pulmonary pressure
What is Cor Pulmonale and what is it commonly caused by?
How do pts. present clinically? (4 major)
CP = isolated right-sided failure (pulmonary HTN)
- parenchymal lung disease (MOST COMMON)
- also lung thromboemboli, primary pulm. HTN (rare)
clinical: hepatosplenomegaly (congestion), distended jugular veins, effusions (peritoneal, pleural, pericardial), edema (gravity dependent), weight gain (fluid accum.)
What does the liver of a pt. with Congestive Heart Failure look like on biopsy?
What emboli can cause Saddle Embolism/Pulmonary Thrombus formation?
- centriolobular hemorrhage and necrosis due to central vein congestion
- “Nutmeg Liver” due to passive congestion
Saddle Embolism/Pulmonary Thrombus:
- DVT, fat emboli from bone fracture, air emboli
What is Congenital Heart Disease and what is it most commonly caused by?
- abnormality of the Heart or Great Vessels due to sporadic genetic mutations or environmental toxins (fetal alcohol syndrome)
- MOST COMMON structural birth defect with VSD (42%) and ASD (10%) being the most common forms
What does a child with Down’s Syndrome look like and what is the most common heart defect associated with them?
child: epicanthic folds and flat facial profile, simian crease of palm, umbilical hernia, gap between 1st/2nd toe
- MOST COMMON genetic cause of congenital heart disease
heart defect: atrioventricular defects or VSD
What heart defects would you see in pts. with:
- Marfan Syndrome (2)
- DiGeorge Syndrome (3)
- Turner Syndrome
- Patau (13) or Edwards (18) Syndromes (3)
- aortic aneurysm or dissection (Fibrillin-1 mutation)
- also see mitral or aortic valve prolapse
- Conotruncal heart abnormalities, ASD, VSD
- “CATCH 22” –> deletion of 22q11 (C = cardiac)
- abnormal face, thymic aplasia, cleft palate, hypocal.
- coarctation of the aorta (45 XO female)
- PDA, VSD, ASD
What is the difference between a Left-Right Shunt and a Right-Left Shunt?
L–>R: high pressure left heart with low pressure right heart
- presents asymptomatically, no cyanosis
R–>L: blood bypasses pulmonary circulation
- cyanosis, hypertrophic osteoarthropathy, “clubbing”
- chronic hypoxia
What are 3 examples of Left to Right Shunts and what are 4 examples of Right to Left Shunts?
L–>R: VSD, ASD, PDA
R–>L: Tetralogy of Fallot, Transposition of the Great Arteries, Tricuspid Atresia, Truncus Arteriosus
What clinical increases are seen in VSD, ASD, and PDA?
What is a serious complication that can occur because of these conditions?
ASD/VSD = inc. right ventricle and pulmonary outflow volumes
PDA = inc. pulmonary blood flow, pulmonary pressure and hypertension
transient increases in right-sided pressure (cough) can cause paradoxical embolus to form do to connections to left heart
Atrial Septal Defects
Where are Secundum, Primum, and Sinus Venosa defects located?
How does ASD typically present?
Secundum: center of atrial septum (90%)
Primum: adjacent to AV valves (5%)
Sinus Venosa: near entrance of Sup. Vena Cava
- anomalous pulmonary venous return
clinical: usually asymptomatic till after > 30 yo –> ejection systolic murmur (can be repaired)
Ventricular Septal Defect
What is its most common form and how does it present clinically?
- MOST COMMON congenital heart disease (90% are membranous VSD)
clinical: HOLOSYSTOLIC murmur, large VSD = right ventricular hypertrophy, pulmonary HTN, SHUNT REVERSAL (cyanosis/death)
What is Eisenmenger Syndrome (Shunt Reversal)?
- occurs when a large Left-Right Shunt (VSD typically) causes increased Pulmonary Blood Flow, leading to endothelial dysfunction and irreversible vascular remodeling (THICKENED WALLS)
- as pulmonary vessel walls thicken, pulmonary vascular resistance increases causing an INVERSION of the shunt (now RIGHT –> LEFT) preventing blood oxygenation from taking place
- leads to CYANOSIS and DEATH
What is a Patent Foramen Ovale?
What is a potential problem of disease?
- open connection between Right and Left atrium that never closed (80% normally by 2 yrs)
- flap can open if right side pressure increases, such as in bowel movements or coughing/sneezing
- potential for paradoxical embolus to form, similar to ASD/VSD/PDA (embolus travels through open flap to left heart)
What is Patent Ductus Arterious caused by (2) and what does it sound like on auscultation?
What does it cause clinically and what are two molecules that can keep it open or close it?
- connection between pulmonary artery and aorta that fails to close due to HYPOXIA or inc. pulmonary vascular pressure (VSD)
- initially left –> right and asymptomatic
- produce harsh, MACHINE-LIKE MURMUR
clinical: large = inc. pulmonary pressure with shunt reversal –> CYANOSIS
- isolated: close with INDOMETHACIN
- preserve: keep open with PROSTAGLANDIN E