Automated External Defibrillator
When someone’s heart stops working, it is known as sudden cardiac arrest. Sudden cardiac
arrest happens to many thousands of people each year. It causes blood to stop flowing
to the brain and other organs. Sudden cardiac arrest can cause a person to die within
minutes. In some cases, an automated external defibrillator (AED) may save a person’s
What is an automated external defibrillator?
An AED is a small, portable, battery-powered machine with a computer in it. The machine
detects heart activity. It can give an electric shock to someone if needed. It uses
small sticky electrodes that are put on a person’s body. The electrodes are attached
to wires. The wires send information from the body to the AED machine. The machine
checks the heart’s electrical system. If certain kinds of abnormal heart rhythms (arrhythmias)
are found, the machine can give the person an electric shock. This shock can reset
the heart’s electrical activity and cause it to beat normally again.
How does an AED work?
The heart has its own electrical system. It controls how the heart contracts and pumps
blood—or “beats.” Heartbeats are known as the heart rhythm. But sometimes a person
can get abnormal heartbeats. These are known as arrhythmias. Some kinds of dangerous
arrhythmias can cause sudden cardiac arrest. One dangerous arrhythmia is ventricular
fibrillation. This causes the heart’s lower chambers to flutter instead of pump. They
can’t move blood when this happens. Another dangerous arrhythmia is called ventricular
tachycardia. This causes the heart’s lower chambers to pump too fast. It can also
cause the heart to not pump blood.
An AED can detect these arrhythmias. It can then give an electric shock to the heart.
This can help it stop an abnormal rhythm and restart a normal heart rhythm that pumps
Using an AED
Anyone can use an AED. Many people—such as first responders, flight attendants, and
people who work in large public facilities—are trained to use an AED. But AEDs are
also made to be used by people with no training. This is because it can save a person’s
life in minutes. There may not be time to find someone who has training. All AEDs
come with instructions. Many AEDs tell the user what to do with voice commands and
make the use as simple as possible. Whenever you are in a public place, look for an
AED station. It could save someone's life.
AEDs are found in many public places where a person may have sudden cardiac arrest:
Airports and airplanes
Trains and buses
You can also buy and learn to use an AED at home. You can find an AED training class
in your area by contacting the American Heart Association at 800-242-8721 or www.heart.org.