B4.069 Cardiomyopathies Flashcards
definition of cardiomyopathy
heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually exhibit inappropriate ventricular hypertrophy or dilatation and are due to a variety of causes that are frequently genetic
can be confined to heart or part of a generalized systemic disorder
often lead to cardiovascular death or progressive heart failure related disability
normal heart weight
female: 250-300 g
male: 300-350 g
RV wall thickness
0.3 to 0.5 cm
LV wall thickness
1.3 to 1.5 cm
hypertrophy
grater heart weight or ventricular thickness
dilation
enlarged chamber size
cardiomegaly
increase in cardiac weight or size
5 classes of cardiomyopathy
- dilated (congestive)
- hypertrophic
- restrictive (infiltrative)
- arrhythmogenic
- unclassified
most common cardiomyopathy
dilated
definition of dilated cardiomyopathy
LV or biventricular dilation, impaired contractility, eventual congestive heart failure
pathogenesis of dilated cardiomyopathy
genetic factors most common viral myocarditis alcohol, chemo, cobalt, cocaine, vasopressors iron overload immunologic abnormailities
how do genetic factors cause dilated cardiomyopathy?
defects in force transmission lead to dilatation, poor contractility
gross pathology of dilated cardiomyopathies
cardiomegaly (>500-900 g) globoid appearance hypertrophy and dilatation flabby myocardium, wall collapses subendocardial scars mural thrombi, apex of LV, emboli
non specific gross pathology of cardiomyopathies
atrophy and hypertrophy of myocardial fibers
interstitial and perivascular fibrosis, subendocardial fibrosis
electron microscopy findings in cardiomyopathy
increased mitochondria and loss of sarcomeres
what are some causes of secondary dilated cardiomyopathies
toxic (ethanol, cobalt, catecholamines, etc)
pregnancy (last trimester, 1st 6 mo after delivery)
viral cardiomyopathy
clinical features of dilated cardiomyopathies
asymptomatic LV dilatation progressive exercise intolerance CHF 75% die within 5 yrs transplantation
definition of hypertrophic cardiomyopathies
L or L/RV hypertrophy and structural derangement asymmetric hypertrophy hypertrophic subaortic stenosis obstructive cardiomyopathy 1:500, genetic factors
genetic factors which can contribute to hypertrophic cardiomyopathies
100 mutations in at least 9 genes encoding proteins of the sarcomere
defects in force generation lead to HCM
most common mutations in hypertrophic cardiomyopathies
- beta-myosin heavy chain 25%
- myosin binding protein C 25%
- cardiac troponin I 3-5%
- cardiac troponin T 3-5%
- alpha-tropomyosin 1%
- myozenin 2 0.04%
gross pathology of hypertrophic cardiomyopathies
cardiomegaly asymmetric myocardial hypertrophy septum/free wall > 1.5 cm obstructive hemodynamic pattern LV thick wall, small cavity, myocardial fibrosis mitral valve floppy and dysplastic
genetic disorders associated with hypertrophic cardiomyopathy
Noonan syndrome
Lentiginosis
Costello syndrome
Mitochondrial hypertrophies
exaggerated hypertrophies (not cardiomyopathy but on differential)
hypertensive LVH
athletes heart
neonatal cardiomegaly
clinical features of hypertrophic cardiomyopathies
asymptomatic screening of family sudden death dyspnea, angina, syncope unsuspected HCM at autopsy of sudden death in a young competitive athlete
treatment of hypertrophic cardiomyopathy
B blockers
Ca channel blockers
surgery
definition of restrictive cardiomyopathies
a group of diseases in which myocardial or endocardial abnormalities limit diastolic filling, while allowing contractile function to remain relatively normal
least common form
2 groups of restrictive cardiomyopathies
endocardial
myocardial
3 conditions with endomyocardial involvement
endomyocardial fibrosis
loeffler endocarditis
endocardial fibroelastosis
endomyocardial fibrosis
equatorial Africa
CHF
death
children and young adults
loeffler endocarditis
temperate zones CHF death men in 5th decade hypereosinophelia, myeloproliferative disorder
endocardial fibroelastosis
focal or diffuse thickening, LV
first 2 years of life
pathology of endomyocardial diseases
grayish white thickened endocardium
mural thrombi
fibrotic endocardium
conditions with predominant myocardial involvement
amyloidosis
sarcoidosis
storage disease
idiopathic
amyloidosis pathology
cardiomegaly
amyloid infiltrate
clinical presentation of amyloidosis
common cause of death in patients with MM
R sided heart failure
arrhythmias
senile cardiac amyloidosis
elderly patients
transthyretin deposition-better prognosis
staining for cardiac amyloidosis
congo red
apple green birefringences
sarcoidosis
generalized granulomatous disease
non-caseating granulomas, fibrosis
clinical presentation of sarcoidosis
mixed pattern of dilated or restrictive cardiomegaly
CHF
arrhythmias
sudden death
examples of storage diseases
glycogen storage diseases (pompe, cori, Anderson) mucopolysaccharidoses sphingolipidoses (fabry, gaucher) iron storage (hemochromatosis)
what happens in storage diseases
protein cannot be degraded and gets stored in muscle
results of hemochromatosis
Fe deposition
primary or secondary
CHF
dilated heart, brown color, LVH, fibrosis
imaging of hemochromatosis
dilated brown heart
blue dots on Perl’s iron stain
definition of arrhythmogenic cardiomyopathy
primary myocardial disease characterizes by progressive adipose of fibroadipose replacement of ventricular myocardium
“RV arrhythmogenic dysplasia”
gross pathology of arrhythmogenic cardiomyopathy
cardiomegaly fatty infiltration of RV myocardium partial or transmural occasionally biventricular involvement mural thrombi
histopath findings of arrhythmogenic cardiomyopathy
fatty or fibrofatty infiltration of myocardium
pathogenesis of arrhythmogenic cardiomyopathy
congenital defect (aplasia of myocardium) genetic factors (20-30% family inheritance, mitochondrial DNA mutations) acquired factors (chronic myocarditis, immune, viral)
clinical features of arrhythmogenic cardiomyopathy
concealed form
overt electrical heart disorder, typical presentation
RV failure
biventricular failure, late
myocarditis
diverse group of pathologic entities
infections
immune related (postviral, poststreptococcal, SLE)
unknown (sarcoid, giant cell myocarditis)
viral myocarditis
lymph myocarditis + myocyte injury
Chagas disease
trypanosoma cruzi
hypersensitivity myocarditis
inflame infiltrate + eosinophilia
giant cell myocarditis
inflame infiltrate + giant cells + myocyte injury
clinical features of myocarditis
heart failure arrhythmias, dyspnea, palpitations dilated cardiomyopathy sudden death symptoms related to primary disease
specific caridomyopathies
muscular dystrophies can have cardiac manifestations
neuromuscular disorders
histiocytoid cardiomyopathy
ischemic cardiomyopathy (common)
