Flashcards in Cardiac Path Robbins Part 4 Deck (48)
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1
what are cardiomyopathies?
-diseases of the myocardium assoc with mechanical and/or electrical dysfxn that usually exhibit inappropriate ventricular hypertrophy or dilation
-due to variety of causes, often genetic
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cardiomyopathies- types
-dilated (systolic dysfxn)- most common!! (90%)
-hypertrophic (diastolic dysfxn)
-restrictive (diastolic dysfxn)
3
dilated cardiomyopathy
-progressive cardiac dilation and systolic dysfxn
-usually assoc with dilated hypertrophy
4
dilated cardiomyopathy- pathogenesis
-familial (30-50% of cases)- TTN (titin) mutations (20%)- most autosomal dominant
-X-linked- dystrophic protein
-alcohol!!
-myocarditis!!
-cardiotoxic drugs/substances: doxorubicin, cobalt, iron overload
-childbirth (peripartum cardiomyopathy)
-supraphysiologic stress (excess catecholamines)
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dilated cardiomyopathy- morphology
-dilation of all chambers
-mural thrombi are common
-fxnal regurgitation of valves
-interstitial fibrosis
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dilated cardiomyopathy- presentation
-ages 20-50
-progressive CHF- dyspnea, exertional fatigue, dec EF
-arrhythmias
-embolism
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Takotsubo cardiomyopathy
"broken heart syndrome"
-excess catecholamines after emotional/psychological stress
->90% women, ages 58-75
-symptoms- similar to acute MI
-apical ballooning of left ventricle with abnormal wall motion and contractile dysfxn
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Arrhythmogenic right ventricular cardiomyopathy
-right ventricular failure and arrhythmias!!!
-myocardiu1m of right ventricular wall replaced by adipose and fibrosis
-causes ventricular tachycardia and fibrillation, sudden death
-familial (usually autosomal dominant)- defective cell adhesion proteins in desmosomes that link adj cardiac myocytes
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Naxos syndrome
-Arrhythmogenic right ventricular cardiomyopathy
-hyperkeratosis of plantar palmar skin surfaces (mutations in gene encoding the desmosome-assoc protein- plakoglobin)
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hypertrophic cardiomyopathy- caused by?
-genetic disorder- myocardial hypertrophy and diastolic dysfxn- reduced SV
-ventricular outflow obstruction (25%)
-mutations involving sarcomeric proteins (most common- B-myosin heavy chain)
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must be distinguished clinically for hypertrophic cardiomyopathy (HCM)
-deposition diseases
-HTN heart disease
12
hypertrophic cardiomyopathy- morphology
-massive myocardial hypertrophy
-often with marked septal hypertrophy!
-microscopically- myocyte disarray
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hypertrophic cardiomyopathy- central abnormality/clinical featuer
-reduced SV due to impaired diastolic filling!
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hypertrophic cardiomyopathy- consequences of extensive hypertrophy
-foci of MI may occur
-left atrial dilation and mural thrombus
-diminished CO and inc pulm congestion- leads to exertional dyspnea
-arrhythmias
-sudden death
15
most common cause of sudden, unexplained death in young athletes
HCM (hypertrophic cardiomyopathy_
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restrictive cardiomyopathy- due to?
-dec ventricular compliance (inc stiffness)- leads to diastolic dysfxn
-may be secondary to deposition of material within the wall (amyloid) or inc fibrosis (radiation)
-ventricles usually normal size, but both atria can be enlarged
17
Amyloid
-extracellular deposition of proteins which form an insoluble B-pleated sheet
-may be systemic (myeloma) or restricted to the heart (usually transthyretin)
-certain mutated versions of transthyretin are more amyloidogenic
-when amyloid deposits are in the interstitium of the myocardium- restrictive cardiomyopathy results
-Congo red stain- apple-green bifringence ! amyloid!
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other restrictive conditions
-endomyocardial fibrosis
-loeffler endomyocarditis
-endocardial fibroelastosis
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endomyocardial fibrosis
-children/young adults in africa
-fibrosis of ventricular endo and subendo- extends from apex upward- involves tricuspid and mitral valves
-fibrous tissue- diminishes the volume and compliance of chambers- restrictive fxnal defect!!
20
loeffler endomyocarditis
-endomyocardial fibrosis with large mural thrombi
-peripheral eosinophilia and eosinophilic infiltrates in mult organs
-toxic products of eosinophils (major basic protein)- initiate endomyocardial necrosis and then scarring
-many have a myeloproliferative disorder assoc with chromosomal rearrangements involving PDGFR alpha or B genes
21
endocardial fibroelastosis
-uncommon
-fibroelastic thickening involving the left ventricular endocardium
-1st 2 yrs of life
-1/3 of cases- aortic valve obstruction or other anomalies
22
myocarditis- due to?
infl of the myocardium
-most commonly due to a virus- Coxsackie A and B most common!
-other viruses- CMV, HIV, influenza
23
myocarditis- nonviral causes
-Trypanosomes (chagas disease)
-Trichinosis (Trichinella spiralis)- most common helminthic
-Lyme disease (Borrelia Burgdorferi)
-diphtheria (Corynebacterium diphtheriae)
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myocarditis- noninfectious causes
-hypersensitivity myocarditis- immune mediated rxns (RF, SLE, drug hypersensitivity)
-giant cell myocarditis- idiopathic
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myocarditis- morphology
-interstitial infl infiltrate with focal myocyte necrosis
-lymphocytes!!
-hypersensitivity myocarditis
-giant cell myocarditis
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acute pericarditis- types
-serous
-fibrinous and serofibrinous
-purulent or suppurative
-hemorrhagic
-caseous
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serous pericarditis
-produced by noninfectious infl diseases (rheumatic fever, SLE, scleroderma)
-sterile serous effusion
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fibrinous and serofibrinous pericarditis- caused by? symptoms?
-most frequent types of pericarditis!
-serous fluid with fibrinous exudate
-acute MI, postinfarction (dressler) syndrome, uremia, chest radiation, rheumatic fever, SLE, trauma
-pain- sharp, pleuritic, position dependent
-pericardial friction rub- most striking finding!
29
purulent or suppurative pericarditis- caused by?
-active infection caused by microbial invasion of pericardial space
-serosal surfaces- reddened, granular, coated with exudate
-acute infl rxn- produce mediastinopericarditis
-outcome- scarring!- produce constrictive pericarditis
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