Resp 180 Exam 3: Myocardial Infarction

  1. Define myocardial infarction
    A medical emergency in which some of the heart's blood supply is suddenly and severely reduced or cut off, causing myocardium to die because of deprevation of O2 supply. 
  2. Etiology of myocardial infarction
    • acute thrombus from plaque rupture occluding the artery
    • arterial embolization rare
    • coronary artery spasm from drugs
  3. What area of the heart is affected?
    • The left ventrical but damage could extend to right ventricle or atria.
    • In pts. that die, LV less than or equal to 50% mass damage
  4. Anterior Infarcts
    • Larger
    • Worse prognosis than inferior-posterior infarts
  5. Transmural Infarcts
    Involve the whole thickness of mycoardium
  6. Signs and Symptoms of Myocardial Infarction
    • 2/3 pts. symptoms days to weeks before MI
    • Increasing angina-SOB-Fatigue
    • 1st symptom: deep, substernal, visceral pain. radiates to jaw, back and arm. Isn't cured with rest or nitroglycerin
  7. What's the % of acute MIs that are silent or unrcognized?
    20% because it's a mild chest discomfort
  8. Signs of Myocardial Infarction
    • anxious
    • sense of impending doom
    • nausea/vomiting
  9. Other signs of Myocardial Infarction
    • Severe pain
    • restless and apprehensive
    • pale, cool, diaphoretic skin
    • peripheral or central cyanosis
    • thready pulse
    • variable BP
    • distant heart sounds
  10. Complications of Myocardial Infartion
    • *Arrhythmia: in less than 90%. Bradycardia.
    • *Sinus node disturbaces: brady- no biggy unless above 50. tach- bad
    • *Atrial arrhythmia: in 10% 
    • *AV block: Mobitz II-bad
    • *Ventricular arrhythmias: common. Primary VFib1st few hrs. 
    • *Heart Failure
    • *RV infarction
    • *Hypoxemia: abNL V/Q matching, edema, atelectasis, shunting
    • *Hypotenstion: decrease ventricular filling
    • *Cardiogenic shock: mortality less or equal to 65%
    • *Recurring ischemia: pericarditis or pulmonary embolus
  11. Diagnosis and Lab Finding of Myocardial Infarction
    • Diagnosed by history
    • Confirmed by ECG
    • Supported by serial cardiac enzyme changes
  12. Blood Tests of Myocardial Infarction
    • *Creatine Kinase: rises in 4-8 hr, peaks in 24 hrs, and is NL in 3-4 days
    • *Troponin T & I: not in healthy, cardiac injury. Rises 4-6 hr, peaks 12-48 hr, elevated for 10 days.
    • *Lactate dehydrogenase: rise in hr, peaks 2-3 days, NL 8-10 days
  13. Prognosis of Myocardial Infarction
    • of those who die, 60% die of primary VFib before reaching the hospital
    • surviving the initial hospitalization, mortality 8-10% 
    • death in first 3-4 months
  14. Treatment GOALS of Myocardial Infarction
    • Relieve distress
    • Reverse ischemia
    • Limit infarct size
    • Reduce cardiac work
    • Prevent/treat complications
  15. Treatment of Myocardial Infarction
    • Quiet, calm, resful room in CCU
    • Mild tranquilizer
    • Don't smoke
    • Diet-low Na, cholesterol and sat fats
  16. Initial Treatment of Myocardial Infarction
    • Don't deny symptoms
    • Rapid dx, alleviate & stabilize with thrombolytic
    • Establish I.V. & draw blood for enzymes, do ECG
    • Give aspirin
    • Oxygen
    • Morphine IV PRN
  17. Thrombolytic Therapy of Myocardial Infarction
    • Most effective
    • Greatest risk is hemmorrage
  18. Drugs to Reduce Cardiac Work in Myocardial Infarction
    • B-Blockers
    • ACE inhibitors
    • Vasodilators
  19. Rehab for Myocardial Infarction
    • Bed rest 1-3 days
    • Chair rest, passive exercises
    • NL activity after 6 weeks
    • Regular exercise
Card Set
Resp 180 Exam 3: Myocardial Infarction
A medical emergency in which some of the heart's blood supply is suddenly and severely reduced or cut off, causing the myocardium to die because of deprivation of its O2 supply.