MHD: Cardiomyopathy Flashcards
What is a cardiomyopathy?
A primary abnormality of the myocardium not attributable to pressure or volume overload. It involves a progressive impairment of the structure and function of the muscular walls of the heart chambers.
What are the 3 main types of cardiomyopathy?
Dilated
Hypertrophic
Restrictive
Which type of cardiomyopathy is most common?
Dilated cardiomyopathy
Describe the morphological changes seen in dilated cardiomyopathy
Biventricular dilatation causes contractile dysfunction
The myocardium compensates for the dilation with hypertrophy. Interstitial fibrosis can also develop.
Proteins of the ________ are involved with genetic forms of dilated cardiomyopathy
Proteins of the CYTOSKELETON are involved with genetic forms of dilated cardiomyopathy
What are the non-genetic causes of dilated cardiomyopathy?
Myocarditis
Peripartum (due to elevated PRL)
Toxic
Idiopathic
What are the clinical consequences of cardiomyopathy?
Heart failure
Sudden death
Atrial fibrilation
Stroke
What is hypertrophic cardiomyopathy?
Marked LV hypertrophy (septum>free wall)
AKA: IHSS, hypertrophic obstructive cardiomyopathy
How are diastole and systole affected by dilated cardiomyopathy compared to hypertrophic cardiomyopathy?
Systole is affected by dilated cardiomyopathy
Diastole is affected by hypertrophic cardiomyopathy
What is the classical shape of the ventricle in hypertrophic cardiomyopathy?
Banana shaped due to an enlarged intraventricular septum
Describe the histology of hypertrophic cardiomyopathy
Myocytes are hypertrophied and appear haphazardly organized. Interstitial fibrosis can also be seen.
What is the major cause of hypertrophic cardiomyopathy?
Most cases are familial
Autosomal dominant mutation in gene encoding sarcomeric proteins
Mechanically, dilated cardiomyopathy is a defect in ________ whereas hypertrophic cardiomyopathy is a defect in _________
Mechanically, dilated cardiomyopathy is a defect in FORCE GENERATION whereas hypertrophic cardiomyopathy is a defect in ENERGY TRANSFER
Clinical outcome of hypertrophic cardiomyopathy
Diastolic heart failure Exertional dyspnea Harsh systolic ejection murmur Anginal pain Intractable heart failure Arrhythmias
What is the most common cause of sudden death in young athletes?
Hypertrophic cardiomyopathy
What is the treatment for hypertrophic cardiomyopathy?
Medications to enhance ventricular contraction (beta blockers, calcium channel blockers)
Surgical excision of muscle
What is restrictive cardiomyopathy?
A primary decrease in ventricular compliance prevents ventricular filling (expansion) during diastole (systolic function is preserved)
Describe the morphological changes seen in restrictive cardiomyopathy
Enlarged left atrium with are normal LV cavity size, slightly thickened LV wall
What are the causes of restrictive cardiomyopathy?
Radiation fibrosis Amyloidosis Sarcoidosis Inborn errors of Metabolism Endocardial fibroelastosis Loeffler endomyocarditis
What is an amyloid?
A misfolded protein that desposits in the extracellular space causing tissue damage
What are the common features of amyloid deposits?
Beta pleated sheet configuration
Stain congo red in tissue that appears apple-green under polarized light
What is myocarditis?
Inflammation of the myocardium that causes myocardial injury
What are the causes of myocarditis?
Viral (Coxsakie A and B, cytomegalovirus, HIV)
Bacterial (Diptheria, Lyme disease)
Parasitic (Chaga’s disease, trichinosis, toxoplasmosis)
Noninfectious (Immune hypersensitivity, rheumatic fever, giant cell myocarditis, sarcoidosis)
What is the clinical manifestation of the myocarditis?
Wide spectrum
Can cause acute congestive heart failure, arrhythmias and can progress to dilated cardiomyopathy
