Information Sheet
February 2023
Defibrillators (AED's) - Some Facts
This page is put together from questions asked generally and during First Aid courses.
There's still a lot of misunderstanding regarding AED’s.
Did you know?
  • An AED can do nothing for a heart attack
  • A heart attack can develop into something that an AED could help
  • A person having a sudden cardiac arrest can just collapse on the spot, looking as though they are having a fit/seizure
  • That person must be diagnosed immediately
  • If it is a cardiac arrest there will be NO pulse and NO breathing
  • An AED should be used within 2-3mins of casualty collapse, for the best chance for the casualty
  • Without breathing or CPR the person will deteriorate at about 10% per min.
  • An AED must be sought and attached as soon as possible but it will NOT go to “shock advised” if there is still “NO pulse”. The AED will continue to monitor the casualty
  • An AED can not find “NO pulse” it is not in its programme
  • If there is  “NO pulse”, (VT or VF) an AED will probably say “no shock advised”, start CPR or “no shock advised start CPR if required/appropriate”
  • AN AED can not start (shock) a stopped heart. There is no electrical signal
  • If CPR starts activity in the heart (VF or VT) the AED will recognise this and go to “shock advised”
 
VF is Ventricular Fibrillation. This is activity in the heart but it is a chaotic activity and will not pump blood.
​VT is Ventricular Tachycardia. This is activity in the heart and it is too fast to pump blood. 
An AED defibrillates. It does not know if a person has no pulse or a normal pulse, it is not in its programme. It has to have something that it can match to its programme. VF or VT (see above). This is why is says start CPR if it cannot find anything, it is the only way to keep oxygenated blood circulating and going to the brain.

Fewer than 1 in 10 people who have a cardiac arrest outside hospital in the UK survive.

Simon Gillespie, former Chief Executive of the British Heart Foundation said:-
"There are 30,000 out-of-hospital cardiac arrests every year. Each day people needlessly die because bystanders don’t have the confidence or knowledge to perform CPR and Defibrillation." 
Put yourself in a position to be able to save a life.
Gain knowledge and confidence through one of our training courses.