- Absence of cardiac electrical activity
- End-stage cardiac rhythm
- May occur after progressive dysrhythmia:
- Prolonged ventricular fibrillation
- 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/ventricular fibrillation (VF); <10% survive to hospital discharge.
- Potentially reversible causes include:
- Drug overdose
- Pulmonary embolism
- Myocardial infarction
Signs and Symptoms
- Unresponsive patient
- No spontaneous respirations
Lightheadedness or Syncope may precede
- Confirm asystole in two limb leads to exclude ventricular fibrillation.
- Confirm lead and cable connections.
- Confirm monitor power is on.
- Confirm monitor gain is up.
- Identify reversible causes.
Diagnostic Tests and Interpretation
Arterial blood gas (potassium)
- Confirm cardiac standstill
- No intervention should be made for patient with valid Do Not Resuscitate document.
- No intervention if patient can be verified as dead:
- Rigor mortis
- Dependent livedo
- Injury incompatible with life (eg, decapitation)
- Initiate basic CPR.
- Confirm asystole with defibrillator.
- Place airway device and confirm placement.
- Establish IV access.
- Confirm asystole in two limb leads with monitor.
- Consider early transcutaneous pacing (within 3–5 min of onset of asystole).
- Epinephrine and atropine every 3–5 min.
- Vasopressin as a one-time dose (optional)
- Treat potentially reversible causes.
- Sodium bicarbonate if hyperkalemia or drug overdose suspected
- No proven benefit to an empiric single countershock.
- Consider induced hypothermia in comatose patients with return of spontaneous circulation
- Target temperature 32–34°C for 12–24 hr
- Consider termination of resuscitation efforts if the following conditions are met:
- Adequate CPR
- Tracheal intubation
- Effective ventilation
- IV access
- VF excluded
- Epinephrine and atropine given:
- Discuss indications of vasopressin versus epinephrine
- Reversible causes corrected
- Documented asystole despite 10 min of above interventions
- Atropine: 1 mg IV q3–5min:
- Epinephrine: 1 mg (peds: 0.01 mg/kg) IV q3–5 min
- Vasopressin: 40 U IV (single dose)
- Sodium bicarbonate: 1 mEq/kg IV only if:
- Pre-existing acidosis
- Tricyclic antidepressant overdose is suspected.
All patients with return of spontaneous circulation
None—all patients with return of spontaneous circulation need at least a period of monitored observation in the hospital.
Appropriate use of a permanent pacemaker may prevent primary asystole:
- High-grade heart block
- Sinus arrest
ICU for cardiac monitoring and induced hypothermia as appropriate
Pearls and Pitfalls
- Confirm asystole in 2 limb leads to exclude ventricular fibrillation
- Resuscitation is likely to be successful only if reversible causes corrected immediately
- Olasveengen TM, Sunde K, Brunborg C, et al. Intravenous drug adminisration during out-of hospital cardiac arrest: a randomized trial. JAMA. 2009;302(20):2222–2229.
- 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cadiovascular Care. Part 7.2: Management of Cardiac Arrest: 7.4: Monitoring and Medications: 7.5: Postresusciation Support. ECC Committee, Subcommittees and Task Forces of the American Heart Association. Circulation. 2005;112:(Suppl. 24):IV58–88.
- Cummins RO, Graves JR, Larsen MP, et al. Out-of-hospital transcutaneous pacing by emergency medical technicians in patients with asystolic cardiac arrest. N Engl J Med. 1993;328:1377–1382.
- Wenzel V, Krismer AC, Arntz HR, et al. A comparison of vasopressin and epinephrine for out-of-hospital cardiopulmonary resuscitation. N Engl J Med. 2004;350(2):105–113.
- Bernard SA, Gray TW, Buist MD, Jones BM, et al. Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. N Engl J Med. 2002;346(8):557–563.
427.5 Cardiac arrest
397829000 asystole (disorder)
David F. M. Brown
© Wolters Kluwer Health Lippincott Williams & Wilkins