Cardiomyopathy Flashcards
What is cardiomyopathy?
primary/intrinsic disease of the cardiac muscle tissue resulting in a structurally and functionally abnormal heart with mechanical and/or electrical dysfunction
not caused by ischemia, HTN, valve defect, congenital deformities, etc.
What are the main types of cardiomyopathy?
(most common)
- dilated (90%, most common)
- hypertrophic
- restrictive
What is dilated cardiomyopathy?
(dysfunction and causes)
progressive dilation of all chambers of the heart resulting in systolic dysfunction
Causes:
- familial (TTN gene -> titin); autosomal dominant
- peripartum
- alcohol (direct toxicity); also, thiamine deficiency (wet beri-beri)
- myocarditis
- doxorubicin (chemotherapeutic)
- iron overload/hereditary hemochromatosis
What morphologic changes are seen in dilated cardiomyopathy?
- eccentric hypertrophy -> chamber dilation
- regurgitation
What are diagnostic features of dilated cardiomyopathy?
Echocardiogram:
- dilation of chambers
- decreased ejection fraction<40%
- normal wall thickness
What is the clinical presentation and exam findings of dilated cardiomyopathy?
Presentation:
- progressive CHF -> edema, dyspnea/fatigue
- systolic dysfunction
- palpitations (arrhythmia)
Exam:
- systolic murmur (regurgitation)
- S3 gallop
- JVD
- rales
- peripheral edema
What are complications of dilated cardiomyopathy?
- A-fib -> thromboembolism (PE or CVA)
- V-fib
- sudden cardiac death
What is takotsubo caridomyopathy?
“broken heart syndrome”
subtype of dilated cardiomyopathy, enlarged left ventricle
-90% women, >60
results in potentially lethal ischemia with emotional distress or catecholamine release
What is arrhytmogenic right ventricular cardiomyopathy (ARVC)?
subtype of dilated cardiomyopathy, right ventricle replaced with adipose and fibrosis -> dilation
-autosomal dominant defect in cell adhesion proteins
causes:
- right heart failure
- V-tach/fib -> sudden cardiac death
What is Naxos syndrome?
autosomal recessive syndrome due to a defect in plakoglobin (as opposed to dominant in isolated ASVD) with arrhytmogenic right ventricular cardiomyopathy
presents as:
- ARVC
- plantar/palmar hyperkeratosis
- wooly hair
- presents in adolescents
V-tach/fib -> sudden cardiac death
What conditions may appear similar to dilated cardiomyopathy?
- ischemic heart disease
- valvular disease
- hypertensive heart disease
What is hypertrophic cardiomyopathy?
genetic disorder due to defect in sarcomeric proteins (most commonly β-myosin) causing cardiac hypertrophy resulting in diastolic dysfunction
What is the epidemiology of hypertrophic cardiomyopathy?
- relatively common 1:500
- male predominance
What morphologic changes are seen in hypertrophic cardiomyopathy?
- concentric hypertrophy favoring the septum (as opposed to physiologic hypertrophy which favors the free wall)
- “banana-shaped” LV due to septal hypertrophy
Microscopic:
-myocyte disarray w/ hypertrophy
What are diagnostic features of hypertrophic cardiomyopathy?
Echocardiogram:
-increased wall thickness
-left ventricular outflow tract obstruction
- systolic anterior motion of mitral valve
- decreased LV size, decreased diastolic filling (preload)/decreased stroke volume -> decreased cardiac output
What is the clinical presentation and exam findings of hypertrophic cardiomyopathy?
typically asymptomatic
Presentation:
- sudden cardiac death in a young athelete
- possible signs of left sided heart failure (dyspnea, syncope)
Exam:
- harsh systolic ejection murmur (LVOT obstruction/SAM)
- S4 gallop
- holosystoic murmur (mitral regurgitation)
- biphasic pulse
What are complications of hypertrophic cardiomyopathy?
- A-fib -> thromboembolism (PE or CVA)
- V-fib
- sudden cardiac death (**classically seen in young athletes**)
What conditions may appear similar to hypertrophic cardiomyopathy?
- hypertensive heart disease -> hypertrophy
- aortic stenosis
What is restrictive cardiomyopathy?
(causes)
decreased ventricular compliance due to proliferation of connective tissue resulting in diastolic dysfunction
most commonly caused by:
- amyloidosis
- radiation
What are diagnostic features of restrictive cardiomyopathy?
Echocardiogram:
- reduced diastolic filling (diastolic dysfunction)
- decreased ventricular volume
- normal ejection fraction (normal systolic function)
What morphologic changes are seen in restrictive cardiomyopathy?
- atrial enlargement
- normal/decreased ventricular volume
*neither change is very specific and not be present in all cases
What is the clinical presentation and exam findings of dilated cardiomyopathy?
diastolic heart failure:
- dyspnea
- peripheral edema
- weakness
- JVD
- ascites
What is the etiology of amyloidosis causing restrictive cardiomyopathy?
- myeloma -> light chain
- inflammation -> serum amyloid A (SAA)
- familial amyloid -> mutated transthyretin
- senile amyloid -> normal transthyretin
How is amyloid restrictive cardiomyopathy diagnosed?
amyloid deposits show apple green birefringence with congo red stain when exposed to polarized light
What is Löeffler endocarditis?
restrictive cardiomyopathy due to eosinophil infiltration
-occurs in diseases associated with eosinophilia
What is endocardial fibroelastosis?
proliferation of fibrous and elastic tissue
-occurs in first two years of life
What conditions may appear similar to restrictive cardiomyopathy?
-restrictive pericarditis
