Lab 1+2 Cardiac Flashcards
Describe the normal morphology and attributes of the chambers of the heart
- RV = crescent shaped; <0.5cm thick
- LV = concentric; 1.3-1.5cm thick
- M = 280-340g / F = 230-280g
The ____ side of the heart ‘drives’ the ____. Why is this so?
- Right; Left
- Right side pre-loads the left side
Where does blood originate from in the right atrium?
from the body
Where does blood originate from in the left atrium?
from the lungs
With concentric hypertrophy, chamber thickness is ____, and chamber volume is ____
increased; decreased
(sarcomeres added in parallel)
Concentric hypertrophy occurs due to a ____ overload
pressure
Name 3 examples of conditions that predispose one to having concentric hypertrophy?
- chronic hypertension
- valvular stenosis
- congenital anomalies (eg. coartcation of aorta)
What term describes the enlarged, hyperchromatic, and rectangular nuclei of thickened hypertrophic myocardial cells?
boxcar nuclei
Describe the histological appearance of boxcar nuclei
- cytoplasmic hypertrophy
- enlarged, hyperchromatic, rectangular nucleus
With eccentric hypertrophy, chamber volume____, chamber size ____, and chamber wall thickness ____.
increases; increases; increases
(sarcomeres added in series)
Eccentric hypertrophy is due to a ____ overload
volume
Name 3 examples of eccentric hypertrophy
- “athlete’s heart” (vol overload during exercise)
- increased blood vol during pregnancy
- dilated cardiomyopathy
How does concentric hypertrophy affect perfusion of heart muscle by coronary arteries?
arteries have further to travel and run out of O2, leading to ischemia
What is the most common cause of left sided heart failure?
ischemic heart disease
What is pulmonary edema?
accumulation of exudate or transudate within alveoli of the lungs
Pulmonary edema often accompanies ____
left ventricular failure
Where are heart failure cells found?
in the lungs
(hemosiderin-laden macrophages)
What are the clinical features of left-sided heart failure?
- dyspnea
- orthopnea (difficulty breathing lying down)
- paroxysmal nocturnal dyspnea (when sleeping for hrs)
- cough (thin, watery)
- hemoptysis (cough up blood)
Dilated jugular veins is termed ____
neck vein distension
Neck vein distension is a result of ____
right-sided heart failure (decreased systemic venous return)
What other signs and symptoms would accompany neck vein distension?
- dependent pitting edema
- chronic passive congestion of liver (nutmeg liver)
- ascites
- hepato/splenomegaly
With right-sided heart failure, where is pitting edema found?
bilateral lower extremity
How is pitting edema severity assessed?
- depth
- time of resorption of pit
What is the most common cause of right-sided heart failure?
LSHF
What is the most common congenital anomaly of the heart?
ventricular septal defect (VSD)
What are the possible consequences of VSD?
- heart failure (vol overload)
- endocarditis (murmur = prone)
- emboli
What are the clinical features of VSD?
- hollow systolic murmur
- appear blue when shunt changes from L->R to R->L (cyanose tardive)
What is the Eisenmenger complex? What is the mechanism?
- shunt initially left to right, later becomes right to left
- progressive increases in pulmonary vascular resistance cause RV pressure to increase, eventually exceeding the LV pressure
What is the most common type of atrial septal defect (ASD)?
ostium secundum
What is Lutembacher syndrome?
combines mitral valve stenosis and ostium secundum septal defect
Patients with Lutembacher syndrome have a much greater risk for ____
RSHF (^^vol overload)
What abnormal communication occurs with a patent ductus arteriosus?
pulmonary trunk communicates with aorta
What are the consequences of patent ductus arteriosus?
- compromised gas exchange
- pulmonic area murmur on auscultation (Machine-like hum)
- cardiomegaly
(under normal conditions should obliterate into ligamentum arteriosum)
Describe the caliber of the aortic valve seen with a congenital bicuspid aortic valve
smaller than normal lumen
What are the consequences of a congenital bicuspid aortic valve?
- LV works harder to overcome smaller lumen -> pressure overload
- LV hypertrophy & calcification
- may lead to endocarditis or sudden death; ^LSHF
What is the classic triad of symptoms seen with congenital bicuspid aortic valve?
- exertional dyspnea
- angina pectoris
- syncope
What cluster of abnormalities encompasses Tetrology of Fallot?
- pulmonary valve stenosis
- RV hypertrophy
- VSD
- over-riding aorta (dextroposition of aorta)
How does a patient with Tetrology of Fallot present at birth? What direction of shunt does this condition produce?
- cyanotic at birth
- right to left shunt
What is the characteristic term given to Tetrology of Fallot visualized on a radiograph?
Boot-shaped heart
(right-sided heart shadow, apex rotated up)
What congenital heart disease is most predictive of clubbing of the fingers?
Tetrology of Fallot
How do patients with left-to-right shunting diseases present at birth?
normal at birth (cyanose tardive)
What congenital disease is characterized by localized narrowing of the lumen of the aorta?
coarctation of aorta
What are the outward signs of an individual with coarctation of the aorta?
- upper limb hypertension (headache, nosebleeds)
- lower limb hypotension (pale, weak, vascular claudication)
What radiographic features would you expect in an individual with coarctation of the aorta?
rib-notching (dilated intercostal aa before/above narrowing)
What are the areas of pale appearance in a heart with acute myocardial infarction?
ischemia/hypoperfusion
What are the darker areas surrounding the pale areas in a heart with acute myocardial infarction?
hyperemia indicating inflammatory response
A histological view of heart tissue after acute myocardial infarction would show ____ necrosis of the heart muscle as evidenced by ____
coagulative
eosinophilia
Within 24 hours post-myocardial infarction, what type of cells would be found in the region?
neutrophils
In healed tissue after myocardial infarct, what is the pale grey material that the necrotic area is replaced by?
collagen-rich connective tissue
What is found at 1 day post-myocardial infarct?
deeply eosinophilic cells (PMNs) with characteristic changes of coagulative necrosis
What is found at 1 week post-myocardial infarct?
- PMNs replaced by macrophages
- ^granulation tissue (pre-scar formation)
What is found at 1 month post-myocardial infarct?
progressive collagenization -> dense fibrous tissue present
Why is each time period in the healing of myocardial infarct important?
each has its own potential complication
In a biopsy of heart tissue taken after an MI, describe the appearance of the myocardium
coagulative necrosis:
- eosinophilic due to lack of nuclei in muscle cells
- neutrophils occupy spaces between dead myocytes
In a biopsy of heart tissue, how long after an MI would there be a distinct lack of nuclei in the myocytes?
1 day (coagulative necrosis)
What is the term given to the apparent colour change in a micrograph of heart tissue 1 day post-MI?
eosinophilic (pink)
At 1 week post-MI, what is a potentially serious complication?
increased risk of myocardial rupture (granulation tissue)
Describe the appearance of healed MI tissue
- ample CT = relatively acellular
- resident fibroblasts within dense scar tissue
What is the causative organism of rheumatic heart disease?
Untreated streptococcal infection
What layers of the heart are affected acutely by rheumatic heart disease?
all layers (pancarditis)
What are Aschoff bodies?
granulomas within the heart during acute rheumatic heart disease
How do Aschoff bodies present?
matrix of chronic inflammatory cells, necrotic debris, and giant cells
What are Anitchkow cells?
Giant cells with caterpillar-shaped nuclei within Aschoff bodies
What valves of the heart are most commonly affected by chronic rheumatic fever?
- mitral valve
- aortic valve
What are the complications of chronic rheumatic fever?
myo & pericarditis heal w/out complications;
endocarditis may lead to chronic complications:
- bacterial endocarditis
- mural thrombi (cardiac vegetations) in atrial or ventricular chambers
- congestive heart failure
- stenosis of valves -> stiff, non-compliant
What is the term for the characteristic appearance of thickened orifice of mitral valve leaflets? What is this a long-term consequence of?
- fish-mouth resemblance
- chronic rheumatic heart disease (endocarditis)
Mitral valve leaflets which protrude superiorly into the atria is termed ____
mitral valve prolapse
What predisposes an individual to mitral valve prolapse?
- familial distribution
- inherited collagen diseases (Marfan syn, Ehlers-Danlos syn, osteogenisis imperfecta)
Auscultation of mitral valve prolapse reveals a characteristic ____
midsystolic click
Why does mitral valve prolapse predispose the patient to endocarditis?
- murmur = turbulence
- damage & inflammation of endocardium in area of turbulence
How does MVP predispose valves to vegetations?
- endocarditis -> damage to valves (Virchow’s triad)
- generate adhesion molecules -> thrombi
What are septic emboli?
thrombo-emboli + bacteria
Where might septic emboli deposit if originating in the LV/mitral valve/aortic valve?
- soles/palms/distal extremities (Janeway lesion/Osler’s node)
-nail beds
-retina (Roth’s spots) - cerebral bleeds?
What are Roth’s spots?
retinal hemorrhages associated with septic emboli originating in the left side of the heart
What are Janeway lesions?
septic emboli to the skin of distal extremities without pain
What are Osler’s nodes?
septic emboli to the skin of distal extremities with pain
Name the 3 types of cardiomyopathy
- dilated (MC)
- hypertrophic
- restrictive
Describe the appearance of dilated cardiomyopathy
enlargement of all chambers, with both ventricles more severely affected (eccentric hypertrophy)
-flabby, pale myocardium
What are the predisposing factors to dilated cardiomyopathy?
- alcohol use
- family predisposition
- CAD, MI, HTN
Describe the organization of myocardial fibers of hypertrophic cardiomyopathy?
myocardial fiber disarray
What are the consequences of myocardial fiber disarray?
- myocardium undergoes significant hypertrophy to compensate
- leads to subaortic stenosis
- compressed branches of coronary aa due to surrounding hypertrophic tissue
What occurs to heart tissue with restrictive cardiomyopathy?
- CT or other protein (amyloid) deposited between cardiac myocytes
- decreased compliance -> resistance to passive filling of heart -> decreased SV and Q
What conditions predispose an individual to restrictive cardiomyopathy?
- amyloidosis, metastatic carcinoma, sarcoid granulomas
- endomyocardial disease
- genetic & storage disease (eg. hemochromatosis)
What is the most common neoplasm of the heart, characterized as a “gelatinous mass?”
cardiac myxoma
What is the age of onset of a cardiac myxoma?
adulthood
What is the cell of origin of a cardiac myxoma?
loose, myxoid stroma (CT eg. fibroblast)
What is the preferential location of a cardiac myxoma?
left atrium
What is the most common pediatric tumor of the heart?
rhabdomyoma
What is the age of onset of a rhabdomyoma?
childhood (pediatric)
What is the cell of origin of a rhabdomyoma?
cardiac myocytes
What is the preferential location of a rhabdomyoma?
ventricles (MC: LV)
Name a proposed mechanism of a “water bottle” appearance (enlarged cardiac shadow) on a radiograph?
Cardiac tamponade:
rapid accumulation of large fluid volume in pericardial cavity due to ruptured MI, dissection, or hemopericardium (blood/exudate filled pericardial sac)
How does a “water bottle” appearance differ from a “boot-shaped” heart?
- boot-shaped: apex angulated upward
- water bottle: enlarged, globular, pericardium ‘sags’
How is cardiomegaly assessed?
Cardiothoracic ratio >0.5
(lat diameter of <3 shadow / lat diameter of thoracic cage)
