Defibrillation means giving an electric shock to try to correct a dangerous heart rhythm during cardiac arrest. In first aid, it is usually done with an Automated External Defibrillator or AED.
Defibrillation is used together with CPR, not instead of it.
What does defibrillation mean?
Defibrillation is the process of delivering a shock when the heart is in a rhythm that may respond to one.
An AED distinguishes rhythms that can respond to a shock from those that cannot. Applying the pads does not mean a shock will be delivered: follow the device prompts, including instructions to continue CPR.
When is defibrillation used?
Apply an AED when a person has both of these signs:
- is Unresponsive
- is not breathing normally
In practical first aid, it fits inside the same early emergency pathway as Primary Survey, DRSABCD, and Basic Life Support.
How does defibrillation fit with CPR?
CPR and defibrillation work together.
CPR helps keep blood moving while an AED is brought to the person and its pads are attached. Pause when the AED directs you to stand clear for rhythm analysis or a shock, and make sure nobody is touching the person during shock delivery. Resume CPR promptly when the device instructs you to.
That means the sequence is usually:
- Call
000. - Start CPR.
- Use an Automated External Defibrillator as soon as one is available.
- Follow the AED prompts and continue CPR when instructed.
Is defibrillation the same as using an AED?
Not exactly.
Defibrillation is the action or process.
An Automated External Defibrillator is the public-use device that checks the rhythm and may deliver the shock.
Why is early defibrillation important?
Some dangerous cardiac arrest rhythms respond best when a shock is delivered early.
That is why early CPR and early AED use are both so important. The sooner the person gets effective first aid, the better the chance of survival.
Quick answer
Defibrillation means giving a shock to treat a dangerous heart rhythm during cardiac arrest. In first aid, it is usually done with an Automated External Defibrillator and used together with CPR when a person is Unresponsive and not breathing normally.
How this page is checked
Publisher: First Aid Glossary Editorial Team
Last reviewed: 28 April 2026
Reviewed against: ANZCOR Guideline 7 – Automated External Defibrillation in Basic Life Support, Healthdirect Australia defibrillator guidance, and Triple Zero emergency-call guidance.
This page is educational and explains first aid language in plain English. It is not personal medical advice, diagnosis, or a replacement for accredited first aid training. In an emergency in Australia, call Triple Zero (000).
