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.

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.

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.

Police and ambulance crews carry AEDs, and they're commonly available in many public places, including malls, office buildings, sports arenas and airplanes. However, many cardiac arrests occur at home, so having a home AED can save precious minutes in reviving a person with ventricular fibrillation.

Proponents of home AEDs say putting them where they're needed most will save thousands of lives each year. But critics argue there's no reliable evidence that home defibrillators save more lives. Critics also fear that people won't call for emergency medical services at all or quickly enough, that they won't maintain their AED properly, or that they'll forget where it is.

For some people who have a high risk of cardiac arrest, having an AED can provide peace of mind and might help save their lives. Here are some things to keep in mind as you consider whether to buy an automated external defibrillator:

  • Your risk of sudden cardiac death. If you're at high risk of sudden cardiac death due to a specific heart rhythm problem, your doctor will likely recommend an implantable cardioverter-defibrillator (ICD) rather than an AED.
  • Your living arrangements. You need someone with you to use the AED if you have cardiac arrest. And the person needs to be agile enough to get on the floor to use the device and get back up. If you live alone or if the person you live with can't get up and down, a home AED might not make sense.
  • Your costs. Home AEDs can be expensive and aren't usually covered by insurance.
  • Your overall health and philosophy. If you have numerous medical problems, a terminal illness or a very weak heart that hasn't responded to treatment, you might choose not to be resuscitated from sudden cardiac death.

If you get an AED for your home, make sure that family, friends and visitors know where it is and how to use it. And you need to maintain it properly. Here are some tips for maintaining your home AED:

  • Register your AED with the manufacturer. That way you'll receive safety alerts and recall notices. Also, check the manufacturer's website periodically to keep current on information about your device.
  • Learn what you need to know. Consider enrolling yourself and whoever might need to use your home AED in a community education class, such as classes offered by the American Red Cross, to learn how to use your automated external defibrillator properly and to perform CPR.

    This will also enable you to come to the rescue if someone has cardiac arrest in a public place and there's an AED nearby.

  • Have a practice run using the AED as you would in an actual emergency. Because the AED works only on certain types of cardiac arrest, the people who might need to use the device should know what steps to take if the AED indicates a shock isn't needed, but the person remains unresponsive.
  • Store your AED in an easily accessible place. Make sure family, friends and visitors know where it is.
  • Keep the AED maintained properly, including installation of new batteries as needed, typically every four years, and replacement of electrode pads as needed.
  • Heed alarms. Home AEDs are designed to test themselves to make sure they're working properly. Be sure you can hear the alarm. If your machine starts beeping or you see a light flashing, call the device manufacturer. Have the number handy.
  • Buy the right AED for you. Some AEDs aren't intended for home use, but rather for emergency crews or for installation in public places. Don't be lured by websites or other sellers offering AEDs not intended for home use.

AEDs offer a way to save a life. Before buying one, talk to your doctor and do research. And don't forget to learn the basics, such as CPR.

April 19, 2017