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Chapter 12 : Asystole

Video Demonstration


Asystole is associated with the absence of cardiac electrical activity, contraction of the heart muscle, and cardiac output. “Flatline” is a term used for no electrical activity seen on the ECG. However, “flatline” can result from other causes such as:

  • Leads are properly connected
  • Power unit is on
  • Signal gain/amplitude/strength is not turned down or too low
  • The rhythm doesn’t look like another pattern

Asystole can be caused by many factors and are represented as H’s and T’s:

Hypovolemia – Decreased blood volumeTension pneumothorax – air in the pleural space around the lung (lung collapses)
Hypoxia- decreased partial pressure of oxygen in bloodTamponade – compression of the heart produced by excess fluid surrounding the heart
Hydrogen ion (acidosis) – Increase in the concentration of H ions in bloodToxins – poisonous substances
Hyper-/hypokalemia –abnormally high or low potassium concentration in the bloodThromobosis (pulmonary) – formation of a blood clot which blocks a blood vessel in lungs
Hypothermia – body temperature less than 30 degrees C (86 degrees F)Thrombosis (coronary) –formation of a blood clot which blocks a blood vessel in heart

Scenario: You are a paramedic and arrive on the scene.  A man is lying on the floor unconscious and the neighbor tells you that she saw the man collapse as he was unlocking his front door.


  1. Check for responsiveness – Tap and shout “Are you alright?” and look at chest for movement.
  2. Check carotid pulse and note no pulse is present


  1. If no pulse, immediately start compressions at a rate of 100 compressions per minute and allow chest to recoil. 30 compressions to 2 breaths.
  2. Prepare to transport patient to the nearest hospital, while continuing effective CPR
  3. Attach monitor and check for shockable rhythm, if no shockable rhythm present, the patient is in asystole or PEA, start CPR for 2 mins and obtain IV/IO access

Management:  AT the hospital initiate the cardiac arrest algorithm on the right if the patient still has no pulse and does not respond to BLS. Get a code team in place.

  1. Once IV/IO access is obtained give the following drugs:

    1. Epinephrine 1 mg IV/IO and repeat every 3 to 5 minutes
  2. Maintain advanced airway and capnography if needed.
  3. Pause and check for shockable rhythm.  If not shockable , continue CPR for 2 minutes and try to treat the reversible causes

The following is an algorithm shows management of cardiac arrest due to asystole/PEA (left side of chart)


Note: When conducting the BLS and ACLS survey on a patient with asystole, there may be times when you should hold resuscitative efforts; those include:

  • Signs of irreversible death like rigor mortis
  • DNAR – Do Not Attempt Resuscitation
  • Threat to safety of the providers
  • Living Will/Family Wishes

Learning Outcomes:
You have completed Chapter VIII. Now you should be able to:

  1. Apply the Cardiac Arrest Algorithm to Asystole
  2. Recognize asystole in a patient
  3. Understand the H’s & T’s in relation to Asystole/PEA
  4. Understand when it is necessary to hold resuscitation
  5. Understand the treatments used in Asystole

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