Lecture 6: Cardiomyopathy Flashcards
Cardiomyopathy (Def)
Geterogenous group of disease of mycardium w/ mechanical/electrical dysfunction w/ ventricular hypertropy or dilation
Are cardiomyopathies ever genetic?
Yes, typically.
To diagnose cardiomyopathy, you must exclude…
Coronary, valvular, and HT diseases
Mechanical dysfunction can lead to…(and 4 symptoms)
Progressive heart failure (dyspnea, fatigue, edema, syncope)
Electrical dysfunction can lead to…
Arrhythmias and sudden death
Two classifications of cardiomyopathy
Primary (confined to heart) or secondary (part of generalized systemic disorder)
Morphological and functional classifications of cardiomyopathy (3)
Dilated (progressive dilation and systolic dysfunction); Hypertrophic (decreased compliance –> diastolic dysfunction); Restrictive (stiff mycoardium, decreased compliance –> diastolic dysfunction)
What is the most common cardiomyopathy? Which is associated with decreased ejection fraction?
Dilated; dilated again!
100% of which morphological cardiomyopathy is related to genetics?
Hypertrophic
Dilated cardiomyopathy is generally concomitant with…
Hypertrophy of ventricle
What do we see in the heart w/ hypertrophic cardiomyopathy? (3)
Thickened ventricle wall, reduced LV volume, enlarged LA
In all 3 morphological cardiomyopathies, what is enlarged?
LA
Describe patients with dilated cardiomyopathy (age, onset)
Typically 40-50 years of age, insidious onset
The causes of dilated cardiomyopathy are…given examples
Diverse! Idiopathic, familial (~30%), infectious (viral = coxsackie B), inflammatory, toxic (alcohol), metabolic, muscular dystrophy
What gene is associated with dilated cardiomyopathy?
TTN, encodes for titin, the largest protein expressed in humans
Describe common features of dilated heart
Large, globular, flabby heart; dilation of AV valves, fibrous thickening, mural thrombosis (stasis)
Histologic features of dilate cardiomyopathy are…Name a few findings
Non-specific; myocytes w/ box-car nuclei, some myocytes are attenuated/irregular; interstitial and endocardial fibrosis
What are some disease-related causes of dilated cardiomyopathy? What do we find with viral cardiomyopathy?
Viral: Coxsackie, adenovirus (white spots, congested vessels, lymphocyte aggregates); Parasitic: Chagas (amastigoes within cytoplasm)
Three causes of noninfective cardiomyopathy
Granulomatous inflammatory disease; Hypersensitivity myocarditis; Collagen vascular disease
What is diagnostic of granulomatous inflammatory diseae?
Multinucleated giant cells
What do we see with sarcoidosis?
White patchy discoloration and non caseating granulomas
What do we see with hypersensitivity myocarditis?
Eosinophil-rich infiltrate
What drugs/toxins can lead to dilated cardiomyopathy?
Alcohol, cocaine, chemotherapeutic agents
T/F: Alcohol is a major cause of dilated cardiomyopathy
True
What is a cause of dilated cardiomyopathy that only women get?
Peripartum
What is a metabolic cause of dilated cardiomyopathy?
Hemochromatosis (iron storage disorder)
Hypertrophic cardiomyopathy is an important cause of sudden cardiac death in…
Young males
What is the most common gene related to hypertrophic cardiomyopathy? What kind of heredity?
Genes encoding beta-myosin heavy chain; AD w/ complete penetrance
The hypertrophy is…
Asymmetric: proportionately greater hypertrophy of the interventricular septum (IVS) than the free LV wall
What causes fatal arrhythmias in hypertrophic cardiomyopathy?
Aberrant myofibers in conduction system
How can you tell HT and HCM apart grossly?
HT = concentric, symmetric; HCM = asymetric septal hypertrophy
What is a characteristic gross feature of hypertrophic cardiomyopathy in the mitral valve?
White-ish mitral valve impact lesion
Histologically, what do we see in hypertrophic cardiomyopathy? Why is this important?
Myocardial fiber disarray; regular conduction is not possible –> arrhythmia
Restrictive cardiomyopathy is the ________ common
Least
Primary and secondary etiology of restrictive…
Primary: tropical endomyocardial fibrosis; Secondary: amyloidosis (most common), sarcoidosis, storage/metabolic disorders (hemochromatosis)
Describe Loefflers endomyocarditis
Males, temperate climates, death w/in months, hypereosinophilic states
What do we see in amyloidosis? What stains? What is most common?
Gross: englarged atrium w/ waxy appearance; histologically: pale pink inflitrate; CongoRed (apple green) and immunoflourescent tests; AL
What is Arhythmogenic Right Ventricular Cardiomyopathy (ARVC)? What happens grossly?
Rare, inherited disease with mutations in desmosomal proteins that primarily affects RIGHT ventricle; fatty tissue replaces heart muscle
What is Left Ventricular Noncompaction (LVNC)? What happens grossly?
Arrest in endomycoardial morphogenesis in embryonic development; sponge-like appearance of left ventricular wall
