An Automated External Defibrillator or AED is a medical device that analyzes the heart’s rhythm. If necessary, it delivers an electrical shock, known as defibrillation1, to stop an irregular heart rhythm and allows a normal rhythm to resume following Sudden Cardiac Arrest (SCA).

SCA is an abrupt loss of heart function. Not treated within minutes, SCA can quickly lead to death. Most SCAs result from ventricular fibrillation, a rapid and unsynchronized heart rhythm starting in the ventricles, or the heart’s lower pumping chambers. The heart must be “defibrillated” quickly; for every minute a normal heartbeat isn’t restored, a victim’s chance of survival drops 7-10% percent.2

Lightweight and portable, an AED is a device that delivers an electric shock through the chest to the heart. An AED is the only effective treatment for restoring a regular heart rhythm during SCA and is an easy tool to operate, even for someone with no medical background. The Red Cross believes that all Americans should be within four minutes of an AED and someone trained to use it, and supports the position that improved training and access to AEDs could save 50,000 lives each year.1

AED Frequently Asked Questions (FAQs)2
Q: Why is an AED important?

A: AEDs make it possible for more people to respond to a medical emergency where
defibrillation is required. Because AEDs are portable, they can be used by nonmedical people. They can be made part of emergency response programs that also include rapid use of 911 and prompt delivery of Cardio Pulmonary Resuscitation (CPR). All three of these activities are vital to improving survival from cardiac arrest.

Q: How does an AED work?

A: A built-in computer checks a victim’s heart rhythm through adhesive electrodes. The computer calculates whether defibrillation is needed. If it is, a recorded voice tells the rescuer to press the shock button on the AED. This shock momentarily stuns the heart and stops all activity. It gives the heart the chance to resume beating effectively. Instructions guide the user through the process. AEDs advise a shock only for ventricular fibrillation or another life-threatening condition called pulseless ventricular tachycardia.

Q: Who can use an AED?

A: Non-medical personnel such as police, fire service personnel, flight attendants, security guards and other lay rescuers who have been properly trained can use AEDs.

Q: Is an AED safe to use?

A: AEDs are safe to use by anyone who’s been trained to operate them. Studies have shown that 90% of the time, AEDs are able to detect a rhythm that should be defibrillated. And 95% percent of the time they are able to recommend NOT shocking when the computer shows defibrillation is not indicated.

Q: Where should an AED be placed?

A: All first-response vehicles, including ambulances, law enforcement vehicles and many fire engines should have an AED. AEDs also should be placed in public areas such as sports arenas, gated communities, airports, office complexes, and doctors’ offices. They should also be in any other public or private place where large numbers of people gather or where people at high risk for heart attacks live.

1 American Red Cross
2 heart.org