Cardiomyopathies

Question 1

Dilated Cardiomyopathy (what is it associated with? what are the complications?)

Answer 1

Associated w/

• Alcohol - cardiotoxic
  - Adriamycin - chemo - cardiotoxic
  - Obesity
  - Most viral infection
  - Chagas
  - Cardiotoxic drugs
  - Thiamine def
  - Sleep apnea
  - Genetic - mutant cardiac proteins; usually more surface proteins (cytoskeleton - desmin, dystrophin)
• Complications
  • Heart failure b/c dec pumping ability
  • Cardiac arrhythmias b/c altered myocyte structure messes w electrical impulses
  • Pulmonary edema
  • Valve insufficiency/regurgitation - annulus inc in size and valve no longer covers it
  • Stroke - stasis
  • Sudden cardiac death

*** Can be peripartum - end of pregnancy to 6 mo after giving birth; mom presents w/ sudden death or sudden heart failure

Question 2

Histology of dilated cardiomyopathy v hypertrophic cardiomyopathy

Answer 2

Dilated = large myoctes themselves but spaced out w/ “lacy” fibers inbetween (can see lacy blue w/ trichrome stain)

Hypertrophic = HUGE myocytes; disoriented and tangled; larger patches of fiber not lacy (b/c infarct)

Question 3

Hypertrophic Cardiomyopathy (causes and complications)

Answer 3

Cause = 100% genetic - usually mutations in proteins deeper in myocyte (myosin heavy or light chains, actin, troponins)

Complications

• Can cause functional aortic stenosis b/c mass of LV impinges on aortic valve and outflow tract (dec CO)
• Cardiac arrhythmias
• Sudden cardiac death esp in young athletes

Question 4

What is Restrictive Cardiomyopathy?

Answer 4

Stiffening of myocardium or endocardium that prevents efficient contraction of heart

Causes - amyloidosis, endocardial fibroelastosis, sarcoidosis, pos-radiation therapy, myocarditis

Question 5

2 Common Causes of Restrictive Cardiomyopathy (plus histo/appearance of ea)

Answer 5

1- Cardiac amyloidosis - abnormal fibrils build up; often associated w/ multiple myelomas, other tumors or senile amyloid due to old age

- Looks waxy on gross appearance
- Histo = amorphous acellular material; use congo red stain then polarize --> amyloid turns apple green (apple green birefringence)
- Poor prognosis (senile better prognosis)

2- Endocardial Fibroelastosis

- Rare; usually seen in kids and young adults
- Can be part of HEC - hydrocephalus/endo fib/cataracts
- Thickened and fibrotic endocardium
- Tx - heart transplant

Question 6

Arrhythmogenic Right Ventricular Cardiomyopathy

Answer 6

• RV does not form - all adipose tissue instead (genetic/congenital)
• Hallmark - fatty infiltration and fibrosis of RV myocardium
• Complications
  
  • Sudden death due to arrhythmia
  • Young patients present w/ right heart failure