heart failure

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heart failure
2013-12-09 16:05:07
3220 final exam fall
3220 final exam fall
Show Answers:

  1. preload
    volume and pressure generated in the ventricle at the end of diastole
  2. preload is determined by what two factors
    • 1.  amount of venous return entering the ventricle during diastole 
    • 2. blood left in the ventricle after systole [what's left over]
  3. Afterload
    • resistance to ejection of blood from the left ventricle
    • pressure in the left must exceed aortic pressure before blood can be pumped out during systole 
    • another definition: the amount of resistance your heart has to work against to or overcome to eject blood
  4. systole
    is the pumping aspect of the heart. known as S1
  5. diastole
    the filling aspect of the heart. known as S2
  6. causes of increase afterload
    • HTN
    • CAD
  7. contractility
    • change in tension at a given resting fiber length
    • ability of the heart muscle to shorten
  8. stroke volume
    • volume of blood ejected per beat during systole
    • depends on force of contraction which depend on myocardial contractility 
    • note that anything that afftect contractiility, preload, and afterloaf load can cause heart failure
  9. frank-starling mechanism
    the more the myocardial fibers are stretched, the greater the force of contraction
  10. what happens to contractility in heart failure?
    it decreases thus resulting in less CO
  11. book definition for Heart Failure?
    "complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood."
  12. heart failure may be cause by?
    any interference with normal mechanisms regulating the cardiac output
  13. what mechanism regulate CO?
    • preload: too much or too little
    • afterload: HTN or CAD = more resistance 
    • myocardial contractility: contraction force
    • heart rate: HR = CO x SV
    • alterations in any of these factors can lead to decrease ventricular function
  14. primary causes of Heart failure
    • CAD
    • HTN: due to inc. resistance
    • rheumatic heart Dx: due to rheumatoid fever
    • congenital heart defect: born with bad valves
    • pulmonary HTN: right ventricle affected 
    • cadriomyopathy
    • hyperthyroidism: can become tachy, inc. O2 demand, heart has to work harder
    • valvular Dx
    • note that injure to the heart can cause low CO
  15. precipitating causes of heart failure
    • anemia: inc. O2 demand
    • infection: increase workload on the heart
    • thyrotoxicosis: hyperthyroidism 
    • hypothyroidsm: assoc with high cholesterol which is assoc with heart Dx which can lead to MI 
    • Bacterial endocarditis: from poor oral hygiene and IV pts. 
    • pulmonary Dx: COPD, pulmonary HTN 
    • Hypervolemia: will cause to much preload
  16. what is left heart failure categorized as?
    either diastolic or systolic
  17. out of systolic and diastolic heart failure, which is more common?
  18. left heart failure: systolic failure
    • inability to pump blood effectively and perfuse vital organs
    • increased workload enlarges left ventricle leading to decreased function
    • prevents forward flow of blood
    • blood backs up into the left atrium and pulmonary veins 
    • can lead to pulmonary edema
    • can lead to stress on the right ventricle
  19. most common causes of left heart systolic failure
    • CAD
    • Dilated cardiomyopathy
    • HTN
    • valvular Dx
  20. end result of left heart systolic failure
    left ventricle dilated and hypertrophied [becomes enlarged]
  21. ejection fraction
    • amount of blood ejected per beat
    • estimated by doing an echocardiogram
    • normal ejection fraction is 60-75%
    • decrease is hallmark of ventricular failure
  22. left heart systolic failure symptoms
    • pulmonary vascular congestion
    • dyspnea
    • orthopnea [positional SOB]
    • cough/frothy sputum
    • fatigue [b/c CO dec. causing SOB ]
    • decreased urine output [de. CO leads to dec. blood flow to kidneys]
    • edema
  23. systolic failure exam
    • cyanosis [fingertips]
    • rales [bases of the lungs]
    • pleural effusions [fluid in pleura space]
    • hypotension/hypertension
    • S3 gallop - a third heart sound
    • evidence of underlying CAD Or HTN
  24. sympathetic nervous system activity
    • a compensatory mechanism 
    • triggered by low CO state
    • inc. catecholamine release
    • inc. HR
    • inc. myocardial contractility 
    • peripheral vascoconstriction = inc. BP
  25. neurohormonal response
    • a compensatory mechanism 
    • dec. CO causes dec. blood flow to kidneys
    • kidneys release renin, which converts to antiotensinogen  to angiotensin l 
    • angiotensin l, converted by angiotensin convertin enzyme in lung, to angiotensin ll
    • adrenal cortex release aldosterone
    • retain Na and H2O
    • peripheral constriction
    • dec. in cerebral perfusion pressure
    • posterior pituitary secretes antidiuretic hormone
    • water reabsorbtion in renal tubules
    • porinflammatory cytokines also released
    • endothelin released [vasoconstrictor]
  26. dilation compensatory mechanism
    • a compensatory mechanism 
    • enlargement of the chambers of the heart
    • muscle fibers of the heart stretch 
    • inc. contraction initially leads to increased CO
    • eventually mechanism fails
  27. hypertrophy compensatory mechanism
    • a compensatory mechanism 
    • inc. in muscle mas and cardiac wall thickness
    • will lead to an increase CO but poor contractility and inc. O2 consumption
  28. myocardial hypertrophy
    • myocyte growth
    • up to 6x inc. left ventricle
    • ventricular stiffness
    • dec. contractility
  29. left heart diastolic failure
    • heart failure with preserved systolic function or ejection fraction 
    • can occur alone or with systolic failure
    • more common in women 
    • results from dec. compliance of left ventricle
  30. left heart diastolic failure symptoms
    • dyspnea [SOB] on exertion 
    • fatigue 
    • crackles
  31. left heart diastolic failure diagnosis is based on what three factors
    • sign/symptoms of heart failure 
    • normal ejection function 
    • evidence of diastolic dysfunction
  32. pulmonary edema/acute decompensated heart failure symptoms
    • dyspnea
    • inc. work of breathing
    • pink, frothy sputum
  33. pulmonary edema/acute decompensated heart failure exam
    VQ mismatch
  34. right heart failure
    • inability of the right ventricle to provide adequate blood flow into the pulmonary circulation 
    • can result from left heart failure, COPD, cystic fibrosis 
    • pressure rises in the systemic circulation, casuing edema and hepatosplenomegaly [enlarged liver and spleen]
  35. cor pulmonale
    or right sided heart failure, is an enlargement of the right ventricle due to high blood pressure in the ling usually caused by chronic lung disease
  36. right heart failure symptoms
    • fatigue 
    • dependent edema
    • distention jugular veins
    • liver engorgement
    • ascities
    • anorexia, GI distress
    • cyanosis
    • inc. peripheral venous pressure
  37. diagnostic test
    • CBC - ^ WBC = infection, dec. HNH = anemia
    • chemistris 
    • LFTs - liver function test 
    • TFTs - thyroid function test
    • BNP level - signs of heart failure if elevated
    • ABG - shows hypoxia
    • Echo - meaure ejection fraction, looks @ valve
    • EKG - change in 12 lead may indicate LT ventricular hypertrophy 
    • CXR
    • angiogram - measures CO, EF
    • stress test
    • genetic testing - cardiomyopathy is genetic
  38. BNP levels
    • known as brain natriuretic peptide 
    • secreted from the left ventricle in response to stretch 
    • normal BNP is less then 100
  39. BNP levels can be elevated in patients with
    • falsely elevated in renal dysfunction
    • large pulmonary embolism [due to atrial stretch] 
    • severe sepsis
  40. severity of heart failure is graded on what scale?
    the New York Heart Association's Functional classification scale
  41. the New York Heart Association's Functional classification scale
    scale indicated how little or much activity it takes to make patient symptomatic
  42. the New York Heart Association's Functional classification scale: describe the classes
    • class l: no symptoms with activity [go about normal routine]
    • class ll: symptoms with ordinary exertion 
    • class lll: symptoms with minimal exertion 
    • class lV: symptoms at rest
    • pts. in class three or four who do not respond to treatment may need to be put on the transplant list
  43. stages of heart failure
    A. at risk for heart failure but without structural heart Dx or symptoms [at risk for heart failure]

    B. structural heart Dx but without signs or symptoms of heart failure 

    C. structural heart Dx. with prior or current symptoms of HF

    D. refractory [no responding to meds] HF requiring specialized interventions
  44. Cardiomyopathies
    • diverse group of disease that primarily affects myocardium 
    • most result of remodeling [changing the shape of the ventricle] cause by MI/neurohormonal reponse to ischemic heart Dx and HTN
    • can be secondary to toxic exposure, connective tissue disorders, inflitrative and proliferative disorders, nutritional deficiencies 
    • many cases are idopathic
  45. types of cardiomyopathies
    • dilated cardiomyopathy
    • hypertrophic cardiomyopathy
    • restrictive cardiomyopathy
  46. dilated cardiomyopathy
    • most common form
    • left ventricle becomes enlarged and dilated. can't pump as efficiently 
    • contractility dec. in left ventricle [CO is dec.]
    • sinus tachy, atrial and ventricular dysrhythmias 
    • systemic or pulmonary thrombeombolism 
    • eventually leads to left heart failure
  47. dilated cardiomyopathy associated conditions
    • ischemic heart Dx
    • alcoholism 
    • pregnancy
    • infection
    • nutritional deficiencies 
    • exposure to toxins
  48. hypertrophic cardiomyopathy
    • chamber volume dec. [left ventricle]
    • compliance dec., particularly left ventricle 
    • heart walls thickens, less space for blood
    • ledd blood fills from chamber and is pumped out
    • can develop atrial and ventricular dysrhythmias
  49. hypertrophic cardiomyopahthy associated conditions
    • HTN
    • aortic stenosis 
    • inherited defect of muscle growth 
    • ex: where you will see young athletes drop dead w/o Sx
  50. restrictive cardiomyopathy
    • portions of heart wall becomes rigid and lose flexibility 
    • compliance dec. 
    • eventually leads to right heart failure
    • least common
  51. restrictive myocardiomyophathy associated conditions
    • amyloidosis
    • sarcoidosis
    • hemochromatosis
  52. takotsubo cardiomyopathy
    • "broken heart syndrome"
    • stress weakening of the heart 
    • "octopus pot" in Japanese
    • can cause lethal heart rhythms 
    • lab screening may look normal