Automated external defibrillators: Do you need an AED?

An AED may save your life during cardiac arrest. Weigh the pros and cons to see if you should get one.

By Mayo Clinic Staff

If you've watched a TV medical drama, you've probably seen someone whose heart stops beating and then is suddenly shocked back to life by a doctor who yells "clear" before delivering a jolt of electricity to the person's chest.

This type of procedure isn't limited to the hospital. It can be done at home if you have an automated external defibrillator (AED), a lightweight, portable device available without a prescription. If you have severe heart disease, you're at risk of sudden cardiac arrest.

AEDs can resuscitate you only if you have a specific type of heart rhythm problem. Talk to your doctor about whether owning an AED could help save your life.

When is an AED needed?

AEDs are used to revive someone from sudden cardiac arrest, which usually occurs with a disruption in the heart's electrical activity that causes the heart to beat dangerously fast (ventricular tachycardia) or irregularly (ventricular fibrillation). Because of this altered heart rhythm (arrhythmia), your heart can't pump effectively.

The arrhythmia stops blood flow to your brain and other vital organs, usually resulting in death if not treated within minutes. If you survive, you can have permanent damage to your brain and other organs, so the sooner your heart's rhythm is restored the better.

If you're having ventricular fibrillation or ventricular tachycardia and an AED is nearby, a bystander in a public place or a family member at home can attach the self-sticking pads to your chest. The AED then reads your heart rhythm and sends an electrical current to your heart if an electric shock can correct the rhythm. If used within minutes, the jolt can restore your heart to a normal rhythm and possibly save your life.

Cardiopulmonary resuscitation (CPR) after cardiac arrest can keep blood flowing to your heart and brain for a time. But often only defibrillation can restore the heart's normal rhythm. Together they can improve your chances of survival.

How to use an AED

If you need to use an AED on someone, first call 911 or your local emergency services to get help on the way. Then begin CPR before you turn on the AED, and start CPR again after the shock is delivered if CPR is still needed.

The home AED comes with an instructional training video that shows how to use and maintain the device. If you buy an AED, everyone in your home should watch the video and review it periodically.

In an emergency, the automated external defibrillator will give you step-by-step voice instructions. It explains how to check for breathing and a pulse and how to position electrode pads on the person's chest.

Once the pads are in place, the AED automatically measures the person's heart rhythm and determines if a shock is needed. If it is, the machine tells the user to stand back and to push a button to deliver the shock. The AED is programmed not to deliver a shock if a shock isn't needed.

The AED will also guide users through CPR. The process can be repeated as needed until emergency crews take over.

April 19, 2017 See more In-depth