All cardiomyopathies are characterized by______dysfunction.
Ventricular
Cardiomyopathies are ________ diseases of the myocardium characterized as ________ cardiac dysfunction, as opposed to dysfunction secondary to ischemia, valvular, or hypertensive diseases.
intrinsic diseases of myocardium characterized by principal cardiac dysfunction
What are the two general types of causes of cardiomyopathies?
Genetic, and acquired.
What is the difference between primary and secondary cardiomyopathies?
Primary cardiomyopathies are diseases solely or predominantly confined to the heart muscle, where as secondary cardiomyopathies or when the heart is part of a generalized multi organ disorder.
What are the three categories of the cardiomyopathies?
Dilated (most common), hypertrophic, restrictive
What is the most common form of cardiomyopathy?
Dilated
Describe dilated cardiomyopathy.
Progressive hypertrophy and dilation of all four chambers leading to systolic failure.
Name seven potential causes of dilated cardiomyopathy.
Infection/myocarditis, drugs like anthracyclines such as doxorubicin, toxins, metabolic disorders, neuromuscular disorders, childbirth, genetics.
______% of cases of dilated cardiomyopathy are familial, mostly autosomal dominant, affecting genes that encode cytoskeletal/sarcomere/microtubule proteins like titin/connectin, TNN.
25-35%
In what age range is dilated cardiomyopathy most often seen?
25-50 year olds
In end-stage dilated cardiomyopathy, the ejection fraction is typically less than _____% of normal.
less than 25% of normal
Only ____% of patients with dilated cardiomyopathy survive for two years and only ____% survive for five years or longer.
50, 25
What is the definitive treatment for dilated cardiomyopathy?
Cardiac transplantation.
Describe the morphological changes associated with dilated cardiomyopathy.
Enlarged heart 3 to 4 times the normal size, flabby, with dilation of all four chambers.
Are mural thrombi common and dilated cardiomyopathy? What is the biggest complication from the mural thrombus?
Yeah common, thromboemboli is the complication.
Is coronary artery occlusion common in dilated cardiomyopathy?
Nope
What microscopic morphological changes are common in cardiomyopathy?
Hypertrophied myocytes with enlarged nuclei, other myocytes show signs of degeneration; variable interstitial and endocardial fibrosis.
In hypertrophic cardiomyopathy, the hypertrophy is out of _______ compared to the hemodynamic load.
proportion
In hypertrophic cardiomyopathy there is disproportionate thickening of the left part of ventricular septum, causing the chamber to be ________ shaped. This is also known as ____ _____ ______.
banana. aka assymetrical septal hypertrophy
In hypertrophic cardiomyopathy, concentric hypertrophy is seen in ____% of cases.
10
What causes hypertrophic cardiomyopathy?
Autosomal dominant missense gene mutations in one or more genes encoding sarcomeric proteins such as in the Beta myosin heavy chain.
Describe the myofiber orientation in hypertrophic cardiomyopathy.
Disarray; not parallel, branches running in all directions
What is the main cause of death in young athletes with hypertrophic cardiomyopathy?
Arrhythmias
Restrictive cardiomyopathy is characterized by a primary decrease in ventricular ________, resulting in impaired ______.
compliance resulting in impaired filling
What is the least common type of cardiomyopathy?
Restrictive
What is the only histologic abnormality in restrictive cardiomyopathy?
Interstitial fibrosis
What disease does restrictive cardiomyopathy invariably progress to?
Congestive heart failure
Name four causes of restrictive cardiomyopathy.
- Interstitial infiltration of amyloid.
- Endomyocardial diseases.
- Storage diseases like hemochromatosis
- Markedly increased interstitial tissue
How does amyloid stain with Congo red stain?
It stains apple-green in cross-polarizing light.
Describe the gross morphological changes of restrictive cardiomyopathy.
Ventricles are normal size, maybe slightly enlarged, cavities are not dilated, myocardium is firm.
What is myocarditis?
Inflammation of the myocardium with myocyte necrosis and degeneration. Inflammation is the primary cause of the disease.
In what population has myocarditis most common?
Children 1-10 years old
What are the two major complications of myocarditis?
- acute biventricular heart failure in previously healthy children/young adults.
- Arrhythmias –> sudden cardiac death (SCD)
What are the three causes of myocarditis?
- Viral
- Non-viral infections
- Hypersensitivity/immunological.
What are the major causes of myocarditis?
- Viral infections, mostly coxsackieviruses (injury is due to immune response agaist virally-infected myocardial cells).
- Non-viral organisms such as Trypanosoma cruzi (causative agent for Chagas disease), Trichinosis, Borrelia burgdorferi (Lyme disease).
What are the four types of myocarditis?
- Lymphocytic myocarditis
- Hypersensitivity myocarditis
- Giant cell myocarditis
- Chagas disease
What morphological changes are characteristic of Lymphocytic myocarditis?
Infiltrate of mononuclear inflammatory cells with diffuse myocardial degeneration and necrosis.
What morphological changes are characteristic of Hypersensitivity myocarditis?
Interstitial inflammatory infiltrate of eosinophils and monocytes with diffuse myocardial degeneration and necrosis.
What morphological changes are characteristic of Giant cell myocarditis?
Mononuclear inflammatory cells with lymphocytes and macrophages, extensive muscle loss, and multinucleated giant cells.
Where is Chagas disease most common? What is the treatment?
South America, no Tx
What is a myxoma?
A benign primary neoplasm of the heart.
Myxomas are often associated with clonal abnormalities of chromosomes 12 and 17 and are thought to arise from primitive multipotent _________ cells.
mesenchymal
_____% of myxomas arise in the left atrium as a glistening, gelatinous, polypoid mass 5-6cm in diameter with a short stalk.
75
Myxomas have a loose myxoid stroma (clear jelly-type crap) of stellate or globular myxoma cells embedded within a background of abundant ________.
proteoglycans.
Do myxomas often form peculiar vessel-like or gland-like structures?
Yeah!
How can a myxoma cause death?
Embolus –> stroke
The normal amount of fluid in the pericardium is 30-50 ml but in pericardial disease there can be up to ______ ______ ml in the pericardium.
several hundred ml
Pericardial disease can cause cardiac tamponade. What is that?
It is when the effusion restricts the heart from filling.
Name five possible causes of pericardial effusion. Which one is most likely after a MI?
- Trauma
- Dissecting aorta
- Vessel infiltration by a tumor
- Cardiac wall rupture (after MI)
- Bleeding diathesis (hypocoagulability)
What is hemopericardium? After what type of event can this occur?
Bleeding into the pericardium - can happen after a MI
Describe the three general types of pericarditis.
- Fibrinous: Exudate effusion rich in monocytic inflammatory cells and collagen. Seen in acute MI, uremia, chest radiation, rheumatic fever, and trauma.
- Purulent/supperlative pericarditis: From invasion of the pericardial space by microbes. Acute inflammation often leads to organization and scarring.
- Constrictive - a potential result of purulent pericarditis.
When during embryonic development do the major cardiovascular structures form?
3-8 weeks.
Congenital heart diseases are seen in approximately ___% of live births.
1
What type of congenital heart disease is most common?
Left-to-right shunt
Name three types of left-to-right shunts. Which one is most common?
- Ventricular septal defect (VSD) - 40%
- Atrial septal defect - 10%
- Patent ductus arteriosus (PDA) - 7%
Which type of left-to-right shunt is associated with increased pulmonary blood volumes?
Atrial septal defect
Which type of left-to-right shunt is associated with increased pulmonary blood pressure and flow?
VSD
Cyanosis is characteristic of what type of heart shunting?
Right-to-left only.
What are the two most common congenital heart diseases that are right-to-left shunts?
Tetralogy of Fallot and transposition of the great arteries.
Clubbing of the fingertips and polycythemia (increased RBCs/blood volume) is characteristic of which congenital heart disease?
Tetralogy of Fallot
What is a paradoxical embolism?
A venous embolism that passes through a right-to-left shunt and causes a stroke.
What are the four anatomical abnormalities seen in Tetralogy of Fallot?
- VSD
- Pulmonary valve (subpulmonic) stenosis
- Overriding aorta
- RV hypertrophy
What causes cyanosis in patients with Tetralogy of Fallot?
The pulmonary stenosis forces blood from the RV to pass into the LV and mix with oxygenated blood, causing O2 desaturation
What two other diseases are patients with Tetralogy of Fallot at risk for?
Bacterial endocarditis and brain abscesses.
What is transposition of the great arteries?
When the aorta arises from the RV and the pulmonary artery arises from the LV
What compensatory anatomical abnormalities usually co-exist with transposition of the great arteries?
Atrial or ventricular septal defect or patent ductus arteriosus.
What is aortic coarctation? How common is it?
A constriction of the aorta at the ductus arteriosus. Makes up 7% of congenital heart diseases.
In which gender is aortic coarctation 2-5 times more common?
Males
Describe the blood pressure discrepancy seen in aortic coarctation.
- Upper body is hypertensive, results in LV hypertrophy
2. Lower body is hypotensive, leads to weakness, pallor, and lower extremity coldness.
What causes notching of the inner surfaces of the ribs in patients with aortic coarctation?
Intercostal arteries, which branch off the aorta proximal to the coarctation become dilated due to the increased pressure and flow. These dilated arteries pulse with the heartbeats and notch the ribs.
