Cardiology: 8.2: CHF Flashcards
Name 5 causes of L-sided heart failure.
- ischemia
- HTN
- dilated cardiomyopathy
- MI
- restrictive cardiomyopathy
What is congestive heart failure?
failure of the heart to pump appropriately
Why does HTN cause CHF?
HTN –> LV hypertrophy = more muscle = harder to oxygenate –> ischemic damage –> pump failure
What is dilated cardiomyopathy?
dilation of all 4 chambers of the heart
Why does dilated cardiomyopathy cause CHF?
systolic dysfunction (ventricles cannot pump) –> biventricular CHF
What are the causes of dilated cardiomyopathy?
- most common = idiopathic
- others:
- Genetic mutation (usually autosomal dominant- ex: Duchenne muscular dystrophy, hemochromatosis, sarcoidosis)
- Myocarditis- usually due to Coxsackie A or B
- Alcohol abuse –> Wet Beriberi (vitamin B1/thiamine deficiency)
- Drugs (e.g., Doxorubicin, Cocaine)
- Pregnancy—seen during late pregnancy or soon (weeks to months) afterchildbirth
- Chagas disease
- *** ABCCCD
What is the tx for dilated cardiomyopathy?
- Na+ restriction
- ACE inhibitors
- β-blockers
- diuretics
- digoxin
- implantable cardioverter defibrillator (ICD)
- heart transplant
What are the complications of dilated cardiomyopathy?
- mitral and tricuspid valve regurgitation
- arrhythmia
What is the inheritance of Duchenne muscular dystrophy?
X linked auto dominant
What causes Duchenne muscular dystrophy?
- frameshift or nonsense mutations —> truncated dystrophin protein –> inhibited muscle regeneration
- “Duchenne = Deleted Dystrophin”
- Loss of dystrophin = myonecrosis
Name the largest protein-encoding human gene.
Dystrophin gene (DMD)
Why do the calf muscles hypertrophy in Duchenne muscular dystrophy?
fibrofatty replacement of muscle
What is the most common cause of death in Duchenne muscular dystrophy?
Dilated cardiomyopathy
What lab findings are seen in Duchenne muscular dystrophy?
- increased CK
- increased aldolase (part of glycolysis)
What does dystrophin do?
- helps anchor skeletal and cardiac muscle fibers
- connects the actin to the transmembrane proteins α- and β-dystroglycan, which are connected to the extracellular matrix (ECM)
Does hypertrophic cardiomyopathy result in increased, normal, or decreased force of contraction?
decreased
If ventricular end diastolic volume (preload) is on the x-axis and stroke volume (or CO) is on the y-axis, how will a Starling curve change in heart failure?
- very increased ventricular end diastolic volume (preload)
- very decreased stroke volume (CO)
- –> curve is shifted down and to the right
What is the most common cardiomyopathy?
dilated
What are the s/s of dilated cardiomyopathy?
- HF
- S3
- systolic regurgitant murmur
- dilated heart on echocardiogram
- balloon appearance of heart on CXR
Why does restrictive cardiomyopathy cause HF?
can’t fill heart appropriately –> can’t pump blood –> LV HF
What are the s/s of L-sided HF?
- pulmonary congestion –> increased hydrostatic pressure in pulmonary vessels –> pulmonary edema (dyspnea, paroxysmal nocturnal dyspnea, orthopnea, crackles)
- heart-failure cells
What are heart-failure cells?
- macs that ingest blood and iron from ruptured pulmonary vessels in heart failure
- iron accumulates –> hemosiderin-laden macs
What do heart failure cells look like? Where are they found?
- they’re brown macs (hemosiderin-laden)
- in the alveolar air spaces
Left-sided heart failure also causes decreased forward perfusion. What does this cause? What is the tx?
- decreased blood flow to the kidneys –> activation of RAAS
- tx = ACE-inhibitors (end in ‘-pril’)
