What are the Two Non-Shockable Rhythms in Cardiac Arrest?
There are four main heart rhythms that can occur during a cardiac arrest. In this blog post, we will take a closer look at the two non-shockable rhythms.
‘Non-shockable’ means that defibrillation is not an effective treatment for these heart rhythms. If an Automated External Defibrillator (AED) detects a non-shockable rhythm, it won’t allow the rescuer to deliver an electrical shock to the victim.
The only treatment of non-shockable rhythms is high-quality CPR and Advanced Cardiac Life Support (ACLS) including drug treatments and identifying any reversible causes of the cardiac arrest.
The two non-shockable cardiac arrest rhythms are:
- Pulseless Electrical Activity (PEA)
Asystole occurs when all electrical activity in the heart stops. This is sometimes referred to as “flat-lining” by the media and medical television shows.
Unfortunately, asystole does not respond to defibrillation and the survival chances for the patient are incredibly low. The only treatment for asystole is high-quality cardiopulmonary resuscitation (CPR) and drugs.
Pulseless Electrical Activity (PEA)
Pulseless Electrical Activity (PEA) occurs when there is a rhythm (normally associated with a pulse) but the patient is in cardiac arrest.
Causes of a PEA cardiac arrest include:
- Severe blood loss
- Low oxygen levels (hypoxia)
- Low body temperature (hypothermia)
- Traumatic injuries
As with asystole, PEA is not treated with defibrillation. Treatment should focus on performing high-quality CPR and identifying the underlying cause of the PEA cardiac arrest.
Once again, unless there is a clearly reversible cause, the survival chances for a patient in PEA are small.