Asystole resident survival guide

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mahmoud Sakr, M.D. [2]


Asystole is a state of no cardiac electrical activity, hence no contractions of the myocardium and no cardiac output or blood flow. Asystole is also known as a cardiac arrest rhythm in which there is no distinct electrical activity on ECG. A (flat line) is another acronym for asystole. In asystole, the heart will not respond to defibrillation because it is already depolarized.


Life Threatening Causes

Asystole is a life-threatening condition and must be treated as such irrespective of the causes. Life-threatening conditions can result in death or permanent disability within 24 hours if left untreated.

Common Causes


Below is an algorithm summarizing the approach to a patient with asystole. Based on the 2010 American heart association ACLS algorithm for asystole[1]

Lead II rhythm generated asystole.JPG
Start CPR for 2 minutes
Give oxygen
Attach monitor and defibrillator
IV/IO access
Epinephrine Q3-5 min
Consider advanced airway, capnography
See VF/VT algorithm
CPR for 2 minutes
Treat Hs&Ts
Epinephrine Q3-5min
ROSC(return of spontaneous circulation
Post–Cardiac Arrest Care


  • Efficiency of CPR can be determined by
    • Monitoring of chest compression rate and depth
    • Adequacy of chest wall relaxation
    • Length and duration of pauses in compression and number and depth of ventilations delivered
    • Physiologic parameters; partial pressure of end-tidal CO2 [PETCO2], arterial pressure during the relaxation phase of chest compressions, central venous oxygen saturation [ScvO2]
  • Remember that the foundation of successful ACLS is good BLS , represented in prompt high-quality CPR with minimal interruptions.[2][3]
  • A new class I recommendation is the use of quantitative waveform capnography for confirmation and monitoring of endotracheal tube placement.
  • Supraglottic advanced airways continues to be an alternative to endotracheal intubation for airway management during CPR.


  • Don't routinely use cricoid pressure during airway management of patients in cardiac arrest.
  • Don't routinely administer atropine in the management of pulseless asystole.


  1. Field JM, Hazinski MF, Sayre MR, Chameides L, Schexnayder SM, Hemphill R; et al. (2010). "Part 1: executive summary: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care". Circulation. 122 (18 Suppl 3): S640–56. doi:10.1161/CIRCULATIONAHA.110.970889. PMID 20956217.
  2. Edelson DP, Abella BS, Kramer-Johansen J, Wik L, Myklebust H, Barry AM; et al. (2006). "Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest". Resuscitation. 71 (2): 137–45. doi:10.1016/j.resuscitation.2006.04.008. PMID 16982127.
  3. Eftestøl T, Sunde K, Steen PA (2002). "Effects of interrupting precordial compressions on the calculated probability of defibrillation success during out-of-hospital cardiac arrest". Circulation. 105 (19): 2270–3. PMID 12010909.