Cardiac Path Robbins Part 4 Flashcards
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
cardiomyopathies- types
- dilated (systolic dysfxn)- most common!! (90%)
- hypertrophic (diastolic dysfxn)
- restrictive (diastolic dysfxn)
dilated cardiomyopathy
- progressive cardiac dilation and systolic dysfxn
- usually assoc with dilated hypertrophy
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)
dilated cardiomyopathy- morphology
- dilation of all chambers
- mural thrombi are common
- fxnal regurgitation of valves
- interstitial fibrosis
dilated cardiomyopathy- presentation
- ages 20-50
- progressive CHF- dyspnea, exertional fatigue, dec EF
- arrhythmias
- embolism
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
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
Naxos syndrome
- Arrhythmogenic right ventricular cardiomyopathy
- hyperkeratosis of plantar palmar skin surfaces (mutations in gene encoding the desmosome-assoc protein- plakoglobin)
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)
must be distinguished clinically for hypertrophic cardiomyopathy (HCM)
- deposition diseases
- HTN heart disease
hypertrophic cardiomyopathy- morphology
- massive myocardial hypertrophy
- often with marked septal hypertrophy!
- microscopically- myocyte disarray
hypertrophic cardiomyopathy- central abnormality/clinical featuer
-reduced SV due to impaired diastolic filling!
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
most common cause of sudden, unexplained death in young athletes
HCM (hypertrophic cardiomyopathy_
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
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!
other restrictive conditions
- endomyocardial fibrosis
- loeffler endomyocarditis
- endocardial fibroelastosis
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!!
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
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
myocarditis- due to?
infl of the myocardium
- most commonly due to a virus- Coxsackie A and B most common!
- other viruses- CMV, HIV, influenza
myocarditis- nonviral causes
- Trypanosomes (chagas disease)
- Trichinosis (Trichinella spiralis)- most common helminthic
- Lyme disease (Borrelia Burgdorferi)
- diphtheria (Corynebacterium diphtheriae)
myocarditis- noninfectious causes
- hypersensitivity myocarditis- immune mediated rxns (RF, SLE, drug hypersensitivity)
- giant cell myocarditis- idiopathic
myocarditis- morphology
- interstitial infl infiltrate with focal myocyte necrosis
- lymphocytes!!
- hypersensitivity myocarditis
- giant cell myocarditis
acute pericarditis- types
- serous
- fibrinous and serofibrinous
- purulent or suppurative
- hemorrhagic
- caseous
serous pericarditis
- produced by noninfectious infl diseases (rheumatic fever, SLE, scleroderma)
- sterile serous effusion
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!
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
hemorrhagic pericarditis
- exudate composed of blood with fibrinous or suppurative effusion
- most commonly caused by malignant neoplasm spread to pericardial space
- also seen in bacterial infections in those with bleeding diathesis and tb
caseous pericarditis
- tb! (fungal infections- less common)
- antecedent of disabling, fibrocalcific, chronic constrictive pericarditis!
adhesive mediastinopericarditis
- may follow infectious pericarditis, cardiac surgery, or mediastinal irradiation
- pericardial sac is obliterated
- adherence to external aspect of parietal layer to surrounding structures- strains cardiac fxn
- heart pulls against parietal pericardium and surrounding structures- rib cage and diaphragm (pulsus paradoxus)
constrictive pericarditis
- dense, fibrous or fibrocalcific scar- limits diastolic expansion and CO
- cardiac hypertrophy and dilation cannot occur
- muffled heart sounds, elevated jugular venous pressure, peripheral eema
rheumatic arthritis
- joint disorder
- subcutaneous rheumatoid nodules
- vasculitis
- neutropenia
- heart involved in 20-40% of cases
rheumatic arthritis- heart involvement
- most common- fibrinous pericarditis- may progress to fibrous thickening of visceral and parietal pericardium
- granulomatous rheumatoid nodules
- rheumatoid valvulitis- marked fibrous thickening and secondary calcification of aortic valve cusps
primary tumors of heart
rare!
- most common- myxoma, lipoma, papillary fibroelastoma, rhabdomyoma, angiosarcoma
- benign!- 80-90% of primary tumors of herat
metastatic tumors of heart
5% of ppl dying of cancer
myxomas
- most common primary tumor of adult heart!
- benign
- arise from primitive multipotent mesenchymal cells
- familial- act mutations in GNAS1 gene or null mutations in PRKAR1A
- 90% arise in atria; 4:1 left:right ratio!
myxoma- morphology
- usually single
- fossa ovalis in atrial septum- favorited site!- can extend into mitral valve orifice
- sessile or pedunculated lesions
- clinical manifestations due to valvular “ball-valve” obstruction, embolization
lipoma
- localized, well-circumscribed, benign tumors
- composed of mature fat cells that can occur in subendocardium, subepicardium, or myocardium
- asymptomatic or can produce ball-valve obstructions or arrhythmias
- most often in left ventricle, right atrium or atrial septum
- in atrial septum- depositions of fat- “lipomatous hypertrophy”
papillary fibroelastoma
- incidental, sea-anemone-like lesions- most ID’ed at autopsy
- may embolize!
- resemble Lambl excrescences
- usually on valves
- distinctive cluster of hairlike projections
rhabdomyoma
- most frequent primary tumor of pediatric heart!
- commonly found in 1st year- obstruction of valvular orifice or cardiac chamber
- 1/2 sporadic
- 1/2 assoc with tuberous sclerosis (TSC1/2 mutations- hamartin and tuberin)
- regress spontaneously
angiosarcoma
-not clinically or morphologically distinctive from their counterparts
most frequent metastatic tumors involving the herart
- carcinomas of lung and breast, melanomas, leukemias, lymphomas
- retrograde lymphatic extension, hematogenous seeding, direct contiguous extension, venous extension
noncardiac neoplasms- clinical syptoms
-pericardial spread- pericardial effusions or mass-effect that is sufficient to restrict cardiac filling
major complication of cardiac transplantation
- allograft rejection
- endomyocardial biopsy- only reliable means of diagnosing acute cardiac rejection before substantial myocardial damage has occured
cellular rejection- characterized by
-interstitial lymphocytic infl with assoc myocyte damage
single most important long-term limitation for cardiac transplantation?
allograft arteriopathy
- late, progressive, diffusely stenosing intimal proliferation in the coronary a’s- leading to ischemia
- 5 yrs of transplantation- 50% of pts develop allograft arteriopathy; all pts by 10 yrs!\
- can lead to a silent MI (pts have denervated hearts)
