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Arrhythmia Following Myocardial Infarction

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Arrhythmia Following Myocardial Infarction, Post-MI Dysrhythmia, Dysrhythmia Associated With Acute Coronary Syndrome

  • See Also
  1. Acute Coronary Syndrome
  2. Electrocardiogram in Myocardial Infarction
  • Causes
  1. Ventricular Dysrhythmias (common post-MI)
    1. Ventricular Tachycardia
    2. Ventricular Fibrillation
    3. Accelerated Idioventricular Rhythm (AIVR)
  2. Bradyarrhythmia
  3. Atrioventricular Block
  1. Non-Sustained Monomorphic Ventricular Tachycardia (duration <30 seconds)
    1. Avoid Antiarrhythmic medications
      1. Suppression of Non-Sustained Ventricular Tachycardia does not decrease morbidity or mortality
      2. Risk of adverse effects
    2. Evaluate for underlying causes
      1. Electrolyte abnormalities
      2. Ongoing coronary ischemia
  2. Sustained Monomorphic Ventricular Tachycardia (duration >30 seconds) or causing hemodynamic instability
    1. Typically caused by Myocardial Infarction scar
    2. Cardioversion for Unstable Patients
    3. Start Antiarrhythmic (choose one)
      1. Amiodarone (preferred, beta blocking activity)
      2. Lidocaine
      3. Procainamide
  3. Polymorphic Ventricular Tachycardia (Normal QTc, non-Torsades)
    1. Typically caused by ongoing coronary ischemia
    2. Cardioversion for Unstable Patients
    3. Start Antiarrhythmic if persists and not cardioverted (choose one)
      1. Amiodarone (preferred, beta blocking activity)
      2. Lidocaine
    4. Prevention following resolution
      1. Consider Beta Blocker
  1. Defibrillate immediately
  2. Following Return of Spontaneous Circulation (ROSC)
    1. Antiarrhythmic medications are not typically recommended for prophylaxis
    2. Consider Beta Blockers to dampen adrenergic surge
  1. Similar appearance to Ventricular Tachycardia, but slower (<130 bpm)
  2. May be associated with reperfusion (e.g. following Thrombolytics, but inconsistent association)
  3. Avoid Antiarrhythmic medications
  4. Evaluate for ongoing Myocardial Ischemia
    1. Consult Cath Lab for possible activation
  • References
  1. Mattu and Swaminathan in Swadron (2022) EM:Rap 22(1): 9-10