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Automated External Defibrillator (AED)

An automated external defibrillator (AED) is a lightweight, portable device. It delivers an electric shock through the chest to the heart when it detects an abnormal rhythm and changes the rhythm back to normal.

AEDs help people who have a sudden cardiac arrest, which occurs when the heart suddenly stops beating regularly. This happens when the heart’s natural electrical system doesn’t work correctly. If not treated within minutes, cardiac arrest quickly leads to death.

Frequently Asked Questions

AEDs save lives. They are an important part of responding to a cardiac arrest. A person’s chance of surviving drops by 7% to 10% every minute a normal heartbeat isn’t restored. So, immediate cardiopulmonary resuscitation, also known as CPR, and AED use can double, or even triple, the person’s chance of survival.

CPR combined with using an AED provides the best chance of saving a life. If possible, use an AED every time you provide CPR.


A person’s chance of survival drops by 7% to 10% every minute a normal heartbeat isn’t restored.

CPR and AED use can double, or even triple, the person’s chance of survivial. 


AEDs are intended for use by the general public (or lay responders). They are portable, safe, accurate, and easy to use.

Although formal AED training isn’t required, it’s recommended to help you increase your level of confidence using it.

AEDs are accurate in detecting when (or when not) to deliver a shock. But even if an AED is used on a nonshockable rhythm, some research shows it may not lower the victim’s chances of survival.

The AED uses voice prompts, lights, and text to tell the rescuer the steps to take.

AEDs may have 2 sets of pads: adult pads and child pads. For CPR, anyone 1 year or older who hasn’t gone through puberty is considered a child. However, for defibrillation, make sure you use the adult pads for anyone 8 years or older.

Follow these steps when using the AED:
  1. Turn on the AED and follow the voice prompts.
  2. Remove all clothing covering the chest. If necessary, wipe the chest dry.
  3. Peel away the backing from the pads and attach the pads to the person’s bare chest following the illustration on the pads.
  4. Plug the pads connector into the AED, if necessary.
  5. The AED will check to see if the person needs a shock and tell you when to give one. While the AED is analyzing, make sure no one is touching the person.
  6. Resume CPR if no shock is needed. If a shock is needed, make sure no one is touching the person and press the Shock button, and then immediately resume CPR.
  7. Continue CPR until emergency medical personnel arrive.

Ambulances, law enforcement vehicles, many fire engines, and other first-response vehicles should have an AED.

The American Heart Association offers CPR and AED training through Training Centers. To locate a Training Center near you, call your nearest AHA office or 1-877-AHA-4CPR (1-877-242-4277). You may also visit heart.org/CPR

Contact for Missing or Alarming AED