Cardiomyopathy Flashcards
What can cardiomyopathies cause?
Heart failure, arrhythmia, or maybe asymptomatic
What are some forms of cardiomyopathies?
- Dilated
- Hypertrophic
- Restrictive
- Arrythmogenic RV
5 LV non-compaction
T or F: Arrhythmogenic right ventricular cardiomyopathy is genetically distinct from other myopathies
T: Arrhythmogenic right ventricular cardiomyopathy appears to be a genetically distinct category, although its clinical phenotype cannot always be easily distinguished from that of dilated cardiomyopathy.
What is impaired in dilated cardiomyopathy?
Impaired contraction of one or both ventricles
LV ejection fraction < 40%
What is dilated cardiomyopathy a result of?
Results from myocyte death and replacement fibrosis from mutations that reduces heart contractility
T or F: coronary arteries are implicated in DC?
F
What are some causes of DC?
- Idiopathic: most common, often genetic (>40 disease genes–abnormalities of cytoskeletal/contractile proteins)
Peripartum cardiomyopathy - Inflammatory/infectious
Viral myocarditis, HIV, Chagas’ disease, Lyme disease
Rheumatic heart disease
Connective tissue diseases (systemic lupus erythematosus) - Toxic/metabolic
Alcohol, cocaine, anabolic steroids
Adriamycin (and other chemotherapy)
Diabetes, thyroid disorders - Neuromuscular disorders
- Tachycardia-induced
- Infiltrative
Hemochromatosis—iron deposition
Sarcoidosis
What are some symptoms of DC?
- Shortness of breath because of high LV diastolic pressure
- Fatigue because of decreased cardiac output
- Peripheral edema because of increased RA pressure
- Occasionally angina because of increased LV wall tension which results in increased myocardial oxygen demand
- Syncope and palpitations because of arrhythmias
What are some physical exam findings of DC?
Tachycardia, BP may be low
Enlarged apical impulse
JVP may be elevated
Third heart sound (volume overload)
Murmur of mitral regurgitation may be present
Dilated LV with lack of coaptation of mitral leaflets results in functional (secondary) mitral regurgitation
What is the most accurate diagnostic tool for DC and what does it show?
Cardiac MRI
Tissue characterization: edema, fibrosis, infarction
What can an electrocardiogram show for DC?
Dilated, spherical left ventricle with ejection fraction < 40%
What does an ECG tell about DC?
Left ventricular hypertrophy
Conduction abnormalities
What are some complications of DC?
Arrhythmias:
- Atrial fibrillation/flutter (distension of left atrium because of increased LA pressure)
- Ventricular (ventricular fibrillation and ventricular tachycardia)
Mitral regurgitation (secondary to increased LV sphericity)
LV thrombus and stroke
Progressive heart failure
What is the therapy for DC?
Life prolonging therapies:
- ACE inhibitors or ARBs
- Beta-blockers
- Spironolactone
- Valsartan/sacubitril (Entresto)
Diuretics as necessary for fluid retention
Cardiac resynchronization if left bundle branch block, EF <35% and NYHA class II-IV
LV assist device or cardiac transplant if NYHA class III-I
What happens to the heart in hypertrophic cardiomyopathy?
Left ventricular hypertrophy with myocardial fiber disarray (wall thickness > 15 mm) and interstitial fibrosis:
- Asymmetric septal hypertrophy most common (septal/posterior wall thickness > 1.5)
- Concentric hypertrophy
- Apical hypertrophy