Asystole

Basics

Description

  • Absence of ventricular electrical activity
  • Nonshockable rhythm
  • 35% of all cardiac arrests
  • Survival to discharge
    • 11% for in-hospital cardiac arrest
    • 1% for out-of-hospital cardiac arrest

Etiology

  • An end-stage rhythm, sometimes degrading from:
    • Prolonged bradycardia
    • Prolonged ventricular fibrillation (VF)
    • Prolonged pulseless electrical activity
  • Patient is extremely unlikely to survive when asystole occurs outside the hospital:
    • ∼40% will have return of spontaneous circulation and survive to hospital admission, but <15% survive to hospital discharge
  • Prognosis is similarly poor for those patients who develop asystole after countershock for ventricular tachycardia/VF; <10% survive to hospital discharge
  • Potentially reversible causes include:
    • Hypoxia
    • Hypovolemia (blood loss)
    • Acidosis
    • Hyperkalemia
    • Hypokalemia
    • Drug overdose
    • Hypothermia
    • Pulmonary embolism
    • Myocardial infarction
    • Tension pneumothorax
    • Cardiac tamponade

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