Heart Failure

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Heart Failure
Emily Crump, Mitchell Luce, Harrison Meyer,
Debbra Muthike
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• African Americans are more likely to develop
  heart failure, earlier in life, more often due to
  hypertension (rather than cardiovascular
  disease), and are more likely to die at a younger
  age due to their disease than are white patients.
  Pharmacological therapy often involves taking an
  ACE inhibitor or angiotensin-receptor blocker
  (ARB), a beta-blocker, and a diuretic. More
  recently, a new type of drug was approved
  specifically for self-identified blacks by the
  FDA a nitric oxide enhancing (NOE) drug, BiDil.

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Hypertension

• Chronically elevated blood pressure
• Many possible causes
• Heredity, lifestyle, diet, other diseases, etc.
• Increases risk of hemorrhagic stroke, heart
  failure, and kidney failure (among others)

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Hypertension in African Americans

• Appears to be linked to
• Social Economic factors
• Education, medical access, etc.
• Geographic lifestyle differences
• e.g. SE has greater hypertension prevalence
• Heritable factors
• Dietary sodium sensitivity, cardiovascular
  reactivity, insulin resistance

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Angiotensin-II

• Angiotensin-II is a neurohormone in the body that
  helps control the cardiovascular system. It is
  not a good thing for people with heart failure.
• It causes BV to constrict which raises BP.
• Also causes the body to release aldosterone which
  causes kidneys to retain sodium and fluid
  resulting in edema.
• Causes the body to release ADH which causes fluid
  retention

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ACE Inhibitors

• ACE (Angiotensin Converting Enzyme) converts
  angiotensin-I to angiotensin-II.
• ACE inhibitors block this enzyme from working.
• This allows for the BV to relax and expand
  (vasodilatation) and thus lowering BP.
• ACE also helps control the volume of blood in the
  body.
• It is then easier for the heart to pump.
• It can take several months for the full effect of
  ACE inhibitors to show.
• Can reduce the risk of death by 20 40.

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ARBsAngiotensin-II Receptor Blockers

• When on ACE inhibitors the action of ACE almost
  stops completely for a while.
• Angiotnesin-II is made in other parts of the body
  too
• ACE inhibitors cant stop it totally and ACE
  levels rise after a period of time.
• ARBs block angiotensin-II receptor sites on the
  cell membrane so angiotensin-II cant effect the
  cell.
• This dilates BVs and lowers blood pressure.

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Diuretics

• Stimulate the kidneys to remove excess sodium and
  water from bloodstream through urination.
• Relieves heart workload, since less fluid to pump
  throughout body.
• If problems with left ventricles, diuretics will
  help remove excess fluid from lungs which can
  improve shortness of breath
• If problems with right ventricle, diuretics will
  reduce extra fluid in tissues that have
  accumulated in legs and abdominal organs.
• Potassium supplement should be taken with
  diuretics.

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Beta Blockers

• Beta-blockers prevent the normal ligand
  (norepinephrine or epinephrine) from binding to
  beta-adrenergic receptors by competing for the
  binding site.
• This inhibits normal sympathetic responses.
• As a result, slows down heart rate and cardiac
  output and dilates blood vessels, which decreases
  blood pressure.
• Can reduce risk of death by 29

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• Bidil is the first drug approved by the FDA for a
  specific racial group.
• Bidil is a combination of 2 older drugs, neither
  approved for heart failure hydralazine and
  isosorbide dinitrate.

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• Hydralazine hydrochloride is an anti-hypertensive
  agent that relaxes the arteries and reduces the
  workload of the heart (decreases resistance).
• Isosorbide dinitrate is a class of drugs called
  nitrates. It dilates blood vessels, also making
  it easier for the heart to pump .
• Isosorbide works by releasing nitric oxide at the
  blood vessel wall, but its effect wears off after
  half a day. Hydralazine may prevent the loss of
  this effect.

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Role of NO at the Heart

• The heart releases a significant amount of NO,
  during systolic as well as diastolic period.
• Under normal conditions NO is produced by
  endothelial cells which are located in close
  proximity with the cardiac muscle cells
  (myoctes).
• Myocyte NO is not stimulated by mechanical forces
  of the heart, but by adrenaline.
• The heart is more sensitive to low supply of NO
  than to low supply of oxygen.
• Cutting of production/supply of NO in the heart
  will terminate a human life in 10-15 seconds,
  much faster than cutting off of oxygen
  supply(5-7min).

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Hypertension is like an overloaded Culvert!
Analogy

• When used in drainage ditches, culverts allow
  water to pass under roadways
• If it rains a lot (as it did last Fall Winter)
  and a culvert is too small or blocked, the ditch
  overflows
• The solution is to either reduce the volume of
  water going through the culvert, or replace it
  with a larger culvert

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References

• http//www.chfpatients.com/ace.htm
• American Heart Association. Medications commonly
  used to treat heart failure. May 29, 2007.
  http//www.americanheart.org/presenter.jhtml?ident
  ifier118
• http//www.fda.gov/news/2005
• www.pubmed.gov
• http//www.postgradmed.com/issues/2002/10_02/sower
  s1.htm