Myocardial Infarction (MI)

  1. General information
    1. The death of myocardial cells from inadequate oxygenation, often caused by a sudden complete blockage of a coronary artery; characterized by localized formation of necrosis (tissue destruction) with subsequent healing by scar formation and fibrosis.
    2. Risk factors: atherosclerotic CAD, thrombus formation, hypertension, diabetes mellitus
  2. Assessment findings (see also Angina Pectoris)
    1. Pain usually substernal with radiation to the neck, arm, jaw, or back; severe, crushing, viselike with sudden onset; unrelieved by rest or nitrates
    2. Nausea and vomiting
    3. Dyspnea
    4. Skin: cool, clammy, ashen
    5. Elevated temperature
    6. Initial increase in blood pressure and pulse, with gradual drop in blood pressure
    7. Restlessness
    8. Occasional findings: rales or crackles; presence of S4; pericardial friction rub; split S1, S2
    9. Diagnostic tests
      1. Elevated WBC
      2. Elevated CPK and CPK-MB
      3. Elevated SGOT or AST
      4. Elevated LDH, LDH1, and LDH2
      5. ECG changes (specific changes dependent on location of myocardial damage and phase of the MI; inverted T wave and ST segment changes seen with myocardial ischemia
      6. Increased ESR, elevated serum cholesterol
  3. Nursing interventions
    1. Establish a patent IV line
    2. Provide pain relief; morphine sulfate IV (given IV because after an infarction there is poor peripheral perfusion and because serum enzymes would be affected by IM injections) as ordered.
    3. Administer oxygen as ordered to relieve dyspnea and prevent arrhythmias.
    4. Provide bed rest with semi-Fowler's position to decrease cardiac workload.
    5. Monitor ECG and hemodynamic procedures.
    6. Administer antiarrhythmias as ordered.
    7. Perform complete lung/cardiovascular assessment.
    8. Monitor urinary output and report output of less than 30 ml/hour; indicates decreased cardiac output.
    9. Maintain full liquid diet with gradual increase to soft; low sodium.
    10. Maintain quiet environment.
    11. Administer stool softeners as ordered to facilitate bowel evacuation and prevent straining.
    12. Relieve anxiety associated with coronary care unit (CCU) environment.
    13. Administer anticoagulants, as ordered.
    14. Administer thrombolytics (tissue-type plasminogen activator or t-pa and streptokinase) and monitor for side effects; bleeding.
    15. Provide client teaching and discharge planning concerning
      1. Effects of MI, healing process, and treatment regimen
      2. Medication regimen including name, purpose, schedule, dosage, side effects
      3. Risk factors, with necessary lifestyle modifications
      4. Dietary restrictions: low sodium, low cholesterol, avoidance of caffeine
      5. Importance of participation in a progressive activity program
      6. Resumption of sexual activity according to physician's orders (usually 4-6 weeks)
      7. Need to report the following symptoms: increased persistent chest pain, dyspnea, weakness, fatigue, persistent palpitations, light-headedness
      8. Enrollment of client in a cardiac rehabilitation program