Cardiomyopathies Flashcards
What is the most common cardiomyopathy? What is the least common?
Most = Dilated Cardiomyopathy
Least = Restrictive cardiomyopathy
Describe Dilated cardiomyopathy. What is the ejection fraction? Mechanism of heart failure? Causes of phenotype? Indirect myocardial dysfunction (mimicking cardiomyopathy)?
EF < 40%
Mechanism = impairment of contractility (systolic dysfunction)
Causes of phenotype: genetic, alcohol, hemochromatosis, etc.
Mimicking = IHD, VHD, HHD, congenital HD
Describe Hypertrophic cardiomyopathy. What is the ejection fraction? Mechanism of heart failure? Causes of phenotype? Indirect myocardial dysfunction (mimicking cardiomyopathy)?
EF = 50-80%
Mechanism = Impairment of compliance (diastolic dysfunction)
Causes of phenotype: genetic, infants of diabetics, storage DO
Mimicking = HHD, aortic stenosis
Describe Restrictive cardiomyopathy. What is the ejection fraction? Mechanism of heart failure? Causes of phenotype? Indirect myocardial dysfunction (mimicking cardiomyopathy)?
EF = 45-90%
Mechanism = Impairment of compliance (diastolic dys)
Causes of phenotype: Amyloidosis, radiation induced fibrosis, idiopathic
Mimicking = pericardial constriction
What is Dilated cardiomyopathy (DCM)?
Progressive cardiac dilation and systolic dysfunction, usually with dilated hypertrophy
What is the genetic basis behind DCM?
Thought to be familial in 30-50% of cases
TTN mutations may account for 20% of all cases
Usually autosomal dominant
What cause is strongly linked to DCM? What else is related?
Alcohol
Myocarditis
Cardiotoxic drugs/substances = doxorubicin, cobalt, iron overload
Why does iron overload occur leading to DCM?
Iron overload from hereditary hemochromatosis (HFE mutation) or multiple transfusions
Use the prussian blue iron stain
What is the morphology of dilated cardiomyopathy?
Dilation of all chambers
Mural thrombi
Functional regurgitation of valves
What is the presentation of DCM?
Usually manifests b/w ages 20-50 yo
Progressive CHF –> dyspnea, exertional fatigue, decreased EF
Arrhythmias (sudden death)
Embolism
What is Takotsubo cardiomyopathy?
A dilated cardiomyopathy
“Broken heart syndrome”
Excess catecholamines following extreme emotional or psychological stress
How does takotsubo cardiomyopathy present?
> 90% in women
Ages 58-75
Sx and sign similar to acute MI
Apical ballooning of the left ventricle with abnormal wall motion and contractile dysfunction
Histologically, what can you observe with DCMs?
Dilation
Myocyte hypertrophy
Interstitial fibrosis
What is arrhythmogenic right ventricular cardiomyopathy (ARVC)? What can it lead to?
Right ventricular failure & arrhythmias
Myocardium of right ventricle wall replaced by adipose & fibrosis
Causes ventricular tachycardia or fibrillation –> sudden death
What is the genetics behind ARVC? What is the pathogenesis?
Familial, Autosomal dominant
Defective cell adhesion proteins in desmosomes that link adjacent cardiac myocytes
What is Naxos syndrome?
ARVC w/ hyperkeratosis of plantar palmar skin surfaces
Mutations in gene encoding the desmosome-associated protein Plakoglobin
What is hypertrophic cardiomyopathy? Describe the genetic changes seen with the dz?
Genetic DO leading to myocardial hypertrophy & diastolic dysfunction, leading to decreased SV & often ventricular outflow obstruction
Numerous mutations known, involving sarcomeric proteins
-most commonly B-myosin heavy chain (B-MHC)
What is the morphology of hypertrophic cardiomyopathy?
Massive myocardial hypertrophy, often with marked septal hypertrophy
Microscopically, myocyte disarray
What are Sx of hypertrophic cardiomyopathy?
Harsh systolic ejection murmur, caused by ventricular outflow obstruction as the anterior mitral leaflet moves toward the ventricular septum during systole
What are the consequences of extensive hypertrophy in hypertrophic cardiomyopathy?
Foci of myocardial ischemia may occur
Left atrial dilation and mural thrombus
Diminished cardiac output and increased pulmonary congestion leads to exertional dyspnea
Arrhythmias
Sudden death (sudden, otherwise unexplained death in young athletes)
What is Restrictive Cardiomyopathy?
Decreased ventricular compliance (increased stiffness), leading to diastolic dysfunction (impaired filling), while systolic function of the LV remains normal
What may restrictive cardiomyopathy be secondary to? What changes to the heart will you see?
May be secondary to deposition of material within the wall (amyloid), or increased fibrosis (radiation)
Ventricles normal size, but BOTH atria can be enlarged
What is amyloid and how does it relate to restrictive cardiomyopathy?
Extracellular deposition of proteins which form an insoluble B-pleated
It is a common cause of RC
May be systemic (myeloma) or restricted to the heart (usually transthyretin)
-certain mutated versions of transthyretin are more amyloidogenic
Amyloid can involve different parts of heart, but when deposits are in interstitium of myocardium = restrictive cardiomyopathy
What is the classic stain associated with amyloid?
Congo red stain = apple green birefringence
What is myocarditis?
Inflammation of the myocardium, most commonly due to virus in US
Coxsackie A/B viruses most common
What other infection is associated with myocarditis?
Trypansoma cruzi (Chagas dz)
- 10% dies during acute attack
- may progress to cardiac insufficiency in 10-20 yrs
- parasitization of scattered myofibers
Will see mixed inflammatory cell infiltrate (PMS, lymphs, macrophages, and occ eosinophils)
What are noninfectious causes of myocarditis?
Immune mediated Rxns:
- RF
- SLE
- Drug hypersensitivity
Histologically, what will you see with Chagas Dz?
Amastigotes
What type of fluid is seen with pericardial dz?
Normal = <50 mL clear, straw colored fluid
What is pericardial dz?
Slow accumulation of fluid,
<500 ml - asymptomatic if slow enough
Globular enlargement of heart shadow on CXR
Acute = 200-300 mL rapid accumulation –> cardiac tamponade
What is most common type of pericardial dz? When will you see it?
Fibrinous and serofibrinous
AMI, postinfarction (Dressler’s), uremia, chest irradiation, RF, SLE, trauma
Describe what fibrinous and serofibrinous pericardial dz look like. What are the Sx seen with them?
Fibrinous = dry, finely granular
Serofibrinous = yellow-brown, turbid fluid with WBC, RBC, and fibrin
Sx: pain (sharp, pleuritic & position dependent), fever, +/- CHF
Loud pericardial friction rub = most striking feature
What is serous pericarditis?
Characteristically produced by non infectious inflamm dz (RF, SLE, Scleroderma, tumors, and uremia)
What is purulent or suppurative pericarditis?
Active infection caused by microbial invasion of pericardial space (direct extension, seeding form blood, lymphatic extension, direct introduction)
What is hemorrhagic pericarditis?
Exudate composed of blood mixed with fibrinous or suppurative effusion
Most commonly caused by spread of a malignant neoplasm to pericardial space
What is caseous pericarditis?
Tuberculous in origin; infrequently, fungal infections evoke a similar reaction
What is constrictive pericarditis?
Heart is encased in dense, fibrinous or fibrocalcific scar that limits diastolic expansion and CO
Features that mimic restrictive cardiomyopathy
What are primary cardiac tumors?
Rare, top 5 = benign
Myxoma, fibromas, lipomas, papillary fibroelastomas, rhabdomyomas,
Angiosarcomas
Metastatic tumors occur in 5% of people dying from CA
What is a myxoma?
Most common primary, predunculated, usually in region of fossa ovalis
Familial syndrome - GNAS1 mutation (McCune-Albright syndrome)
PRKAR1A mutation (Carney complex)
What is the appearance of a myxoma? What are the Sx?
Globular hard mass, mottled with hemorrhage to soft, translucent, papillary, or villous with a gelatinous appearance
Sx = Ball-valve obstruction, embolization or constitutional sx (fever and malaise)
Pedunculated form cause intermittent obstruction during systole of AV valve or wrecking ball causing damage to valve leaflets
Constitutional sx = elaboration of some myxomas of the IL-6, major mediator of the acute phase response
Auscultation = tumor “plop”
What is a lipoma?
Localized, well-circumscribed, benign tumors composed of mature fat cells; subendocardium, subepicardium, or myocardium
What is a papillary fibroelastoma?
Usually incidental, sea-anemone-like lesions, most often identifies at autopsy; usually (>80%) located on valves
Resemble smaller, trivial, labl excresences that may represent remotely organized thrombus on the aortic valves of older indivs
What is a rhabdomyoma?
Most frequent primary tumor of the pediatric heart
- 50% sporadic mutations
- 50% assoc with tuberous sclerosis (TSC1/Hamartin or TSC2/tuberin mutations - TS genes)
What is an angiosarcoma?
Malignant endothelial neoplasm that primarily affects older adults
What are some direct consequences of tumors to the heart?
Pericardial and myocardial metastases
Large vessel obstruction
Pulmonary tumor emboli
What are some indirect consequences of tumors to the heart?
Non-bacterial thrombotic endocarditis
Carcinoid heart dz
Pheochromocytoma-assoc heart dz
Myeloma-assoc amyloidosis
How may cardiac transplants occur? Due to what?
~3000/yr worldwide due to DCM and IHD (most common)
What is a major complication to cardiac transplantation?
What is the survival rate? Histologically, what changes to the heart are seen?
Allograft rejection
-routine endomyocardial bx to monitor
Overall survival = 90% at 1 yr, >60% at 5 yr
Histo = lymphocytic infiltrate, intimal thickening
What is allograft arteriopathy?
Most impt long term limitation
Late, progressive, diffuse stenosing intimal proliferation
50% dev in 5 yr, virtually all pt within 10 yr
Silent MI = denervated transplanted heart = no angina
What can develop in transplant pts due to chronic T-cell immunosuppression?
EBV assoc B-cell lymphoma
