Cardio I

Question 1

describe hypertrophy

Answer 1

• increase in size of the cardiac myocytes
• induction of genes coding for proteins:
  
  • actin, myosin (fetal isoforms of proteins) → increased sarcomers
• usually not accompanied by increase in vascularization → relative decrease in capillary density → ischemia → fibrosis → reduced diastolic relaxation
• coupled with increased metabolic and O2 need → cardiac decompensation

Question 2

describe concentric hypertrophy

Answer 2

• occurs in pressure overload on ventricles
  
  • e.g. HTN, aortic stenosis → new sarcomeres are added in parallel to existing sarcomeres → increased wall thickness and decreased diameter of cavity

Question 3

describe eccentric hypertrophy

Answer 3

• occurs in volume overload on ventricles
  
  • e.g. aortic regurgitation → new sarcomeres are added in series with existing sarcomeres → muscle mass increases proportional to chamber dilatation; there can be significant hypertrophy without any increase in thickness of the walls

Question 4

Answer 4

Question 5

Answer 5

Question 6

describe systolic dysfunction and examples of when it occurs

Answer 6

systolic dysfunction = inability to contract properly

• myocyte loss, e.g. MI
• pressure overload, e.g. hypertension
• volume overload, e.g. valvular regurgitation
• decreased contractility e.g. myocarditis, DCM

Question 7

describe diastolic dysfunction

Answer 7

diastolic dysfunction = inability of the heart to relax and fill

• massive ventricular hypertrophy
• myocardial fibrosis
• amyloidosis
• constrictive pericarditis

Question 8

describe high output failure vs. low output failure

Answer 8

• high output failure:
  
  • occurs due to increased tissue demands e.g. anemia, hyperthyroidism, pregnancy
  • symptoms of heart failure occur in spite of well-functioning heart (high cardiac output)
  • is a systolic dysfunction
• low output failure:
  
  • heart failure with decreased cardiac output
  • majority of cardiac disease causes low output HF

Question 9

describe forward vs. backward heart failure

Answer 9

• forward failure:
  
  • decreased output to the systemic circulation
  • leads to renal hypoperfusion → activation of renin-angiotensin system → sodium and water retention → edema
  • patient would have low BP, fatigue, syncope, shock
• backward failure:
  
  • pulm. congestion → pulm. edema → pulm. HT → RHF → systemic venous congestion → edema, ascites, raised JVP, congested liver

Question 10

describe compensatory mechanisms found in heart failure

Answer 10

Question 11

describe how LHF affects the brain, kidney and lungs

Answer 11

• brain: hypoxic encephalopathy
• kidney: acute tubular necrosis
• lungs:
  
  • gross:
    
    • heavy & wet lungs, cut surface → exudes a frothy mixture of surfactant-rich fluid and blood
  • histo:
    
    • congestion of pulm. alveolar capillaries
    • edema fluid in alveolar spaces
    • persistent cases → brown induration of lungs

Question 12

describe how RHF affects the liver and spleen

Answer 12

• liver:
  
  • chronic passive congestion
  • nutmeg liver
• spleen:
  
  • enlargement and congestion of spleen
• soft tissue edema