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Robbins Chpt 12 cardiomyopathies
Terms in this set (49)
disease whose cause is intrinsic to myocardium. diagnosis by endomyocardial biopsy. can be associated with infections or toxins.
cardiomyopathy associated with pheochromocytomas. causes foci of myocardial necrosis with contraction bands due to excess stimulation by catecholamines.
impairment of compliance (diastolic dysfunction) with myocardial hypertrophy and intermittent ventricular outflow obstruciton.
causes of HCM
genetic (mutation in sarcomere proteins), friederich ataxia, diabetic mothers.
beta myosin in heavy chain
mutations in this gene are the msot common genetic cause of HCM.
major categories of cardiomyopathy
dilated, hypertrophic, restrictive and (rare) left ventricular noncompaction
Left ventricular noncompaction
rare form of cardiomyopathy where myocardium takes on spongy appearance. congenital disorder associated with failure and arrythmias.
cardiomyopathy characterized by progressive cardiac dilation and contractile (systolic) dysfunction usually with concomitant hypertrophy.
enlarged and flabby heart with dilation of all chambers. causes functional regurgitation in mitral/tricuspid valves. hypertrophied myocytes with enlarged nuclei, some of them attenuated or irregular.
genetic causes of DCM
usually autosomal dominant. usually encoding sarcomere or lamina proteins i.e. dystrophin, cardiac alpha actin and lamin A and C or mitochondrial proteins.
infectious causes of DCM
coxackievirus B and other enteroviruses.
toxic causes of DCM
ETOH (thiamene deficiency aka beriveri), chemotherapy drugs (doxorubicin aka adriamycin)
arrythmogenic right ventricular cardiomyopathy. inherited disease of cardiac muscle that causes right ventricular failure and various rhythm distrubances. (v-tach, v-fib). characterized by thinned RV wall and loss of myocytes. AD inheritance pattern
defective cell adhesion proteins in desmosomes that link adjacent cardiac myocytes that are inherited in AD pattern, cause ARVC.
cardiomyopathy characterized by myocardial hypertrophy, poorly compliant left ventricle myocardium leading to abnormal diastolic filling. possible flow obstruction.
morphology of HCM
hypertrophy without dilation. inproportionate thickening of ventricular septum as compared with free wall of left ventricle.
histology of HCM
extensive myocyte hypertrophy to degree unusual. transverse myocyte diameters greater than 40 mm. haphazard dissarray bundles of myocytes. as well as interstitial and replacement fibrosis.
mutations present in genetic forms of HCM. AD inheritance pattern
manifestations of HCM
reduced SV (reduced diastolilc filling) --> exertional dyspnea, harsh systolic ejection murmur, ischemia and anginal pain. mural thrombus and ventricular arrythmias.
Tx of HCM
beta blockers and surgical reduction of ventricular septum to relieve obstruction.
cardiomyopathy characterized by primary decrease in ventricular compliance resulting in impaired ventricular filling during diastole.
causes of RCM
radiation fibrosis, amyloidsos, sarcoidosis, metastatic tumors or deposition of metabolites, idiopathic
morphology of RCM
firm myocardium that is noncompliant. biatrial dilation with pathcy fibrosis
disease of children and young adults in africa. fibrosis of ventricular endocardium and subendocardium that extends from apex upward and involving tricuspid mitral valves
endomyocardial fibrosis with large mural thrombi. similar to endomyocardial fibrosis but involves peripheral eosinophilia and eosinophilic infiltrates to other organs. release of MBP initiates myocardial necrosis.
genetic cause of Loeffler
chromosomal rearrangements involving PDGFRalpha and PDGFRbeta genes. produce fusion genes that encode PDGFR tyrosine kinase. Tx with imatinib has good outcome.
uncommon disease with diffuse fibroelastic thickening usually involving mural left ventricular endocardium. usually in 1st two years of life. -- accompanied by aortic valve obstruction or other anomalies.
damage to endocardium by infectious or inflammatory process.
most common cause of myocarditis. incluldes coxackieviruses A and B as well as other enteroviruses. others are CMV, HIV...
nonviral causes of myocarditis
Protozoans: trypanosoma cruzi, trichinosis (helminth), corynebacterium diptheriae, Lyme disease. Toxoplasmosis.
caused by Trypanosoma cruzi. endemic to south america. organisms infect myocytes and cause 10% of pts to die of acute attack.
most common helminthic disease associated with myocarditis
gram + rod bacterium that secretes diptheria toxin -- direct toxic effects causing myocardial injury.
causes Lyme disease, lyme myocarditis (gram neg bacteria), requires temporary pacemaker.
inflammation and myocyte damage without clear cause or myocarditis caused by HIV directly or by opportunistic pathogen.
morphology of myocardtitis
interstitial inflammatory infiltrate with focal necrosis. endocardial biopsy for diagnosis.
noninfective myocarditis characterized by inflammatory infiltrate and gianty cell formation, eosinophils, plasma cells and macrophages. caused by drug rxns to antibiotics or diuretics, antihypertensives.
tyrosine kinase inhibitors, anthracyclines doxorubicin and daunorubicin. --> DCM. also lithium, phenothiazines, chloroquine and cocaine.
histological change with cardiotoxic drugs
myofiber swelling, cytoplasmic vacuolization, fatty change. resolves with discontinuance of toxic agent.
Catecholamines and the heart
excess stimulation like with pheochromocytoma -- foci of myocardial necrosis with contraction bands and sparse mononuclear infiltrate.
sudden intesne emotional or physical stress (catecholamine release) induces acute left ventricular dysfunction due to myocardial stunning
deposition of abnormal proteinacieous substance in the heart. insoluble beta pleated sheet protein fragments. produces restrictive cardiomypathy. can also be dilation or arrythmia.
senile cardiac amyloidisis
amyloid deposits of transthyretin serum proteins in the ventricles/atria.
who is more likely to have amyloidosis, whites or blacks?
Morphology of cardiac amyloidisis
firm and rubbery myocardial texture. small semitranslucent nodules resembling wax drips on endocardial surface (left heart), distinguished from other deposits by congo red stain.
caused by hereditary hemochromatosis or blood transfusion. iron deposition prominent in vetnricles, cayses sytolic dysfunction by interfering with metal dependent enzyme systems, inducing oxygen free radical injury. "rust brown" color from accumulation of hemosiderin. (prussian blue stain)
tachycardia, palpitations, cardiomegaly. failure is uncommon. nonspecific cardiac hypertrophy with ischemic foci.
decreased cardiac output due to reduced stroke volume and HR. increased peripheral vascular resistance and decreased volume. prolonged circulation time, decreased flow to peripheral tissues. characterized by myxedema of large flabby heart. loss of striations and basophilic degeneration.
when the heart is enlarged and dilated secondary to mucopolysaccharide rich edema fluid accumulation (sometimes in pericardial sac).
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