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
