Myocardial Ischemia

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Myocardial Ischemia

• Present the moment there is a decrease of
  complete absence of blood supply to myocardial
  tissue
• Mild or moderate anoxia can be tolerated for a
  short time by the cardiac cells without greatly
  affecting their function.
• Upon return of adequate blood flow and
  reoxygenation, these cells usually return to a
  normal or near normal condition

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Myocardial Injury

• If ischemia is severe or prolonged, the anoxic
  cardiac cells sustain damage and stop functioning
  normally, unable to contract or generate or
  conduct electrical impulses properly.
• Damage cells still remains reversible so that the
  injured cells remain viable, and salvageable for
  some time.
• Cells may return to normal or near normal after
  the return of adequate blood flow and
  reoxygenation.

3
Myocardial Infarction

• Severe myocardial ischemia continues because of
  continued complete absence of blood supply, the
  anoxic cardiac cell will sustain irreversible
  injury and die
• Necrosis is present
• After occlusion of a CA the myocardium evolves
  through various stages and degrees of severity of
  impairment.

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Acute Coronary Syndromes

• Silent Ischemia
• ST depression with or without pain
• Stable Angina
• Exertion induced angina that remains unchanged
• Unstable Angina
• New onset of angina, increase of existing angina,
  angina at rest gt 20 minutes
• Acute MI
• Plaque rupture with thrombus formation
• Sudden Cardiac Death
• V-Tach or V-fib is the most common cause of 80
  of population
• Asystole or EMD is the cause of the other 20

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Acute Myocardial Infarction

• After occlusion of a CA, the myocardium evolves
  through various stages and degrees of severity of
  impairment
• Myocardial Ischemia-zone of ischemia
• Myocardial Injury-zone of injury
• Myocardial Infarction-zone of infarction (dead
  tissue)

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