Who uses them?

When a person is in cardiac arrest, time is of the essence. Mere minutes can be the difference between full recovery, and death or permanent damage. For this reason, a portable defibulator (also called an external heart defibulator) is a key piece of equipment in any emergency response kit. Most if not all ambulances, and many police cars, have an external defibulator. However, because it can take several minutes for an emergency responder to get on the scene and treat somebody in cardiac arrest with their heart defibulator, many communities are setting up public access defibulation centers, or PAD's. These consist of external defibulators as well as other first aid equipment, and allow volunteers to treat heart attack victims in the crucial minutes before emergency medical services can arrive. 

What do they do?

An Automated External Defibulator (AED) serves the same purpose as an internal defibulator, but it is not implanted. They can only be used when a patient is suffering from cardiac arrest or severe heart fibulation, since the electrical shock they produce can damage a beating heart. An external defibulator used to be found only in hospitals and ambulances, but in recent years the reduced size and cost of these units has brought them into wider use. External heart defibulators have saved countless lives that would have been lost had it not been for the portability and affordability of this new breed of external defibulators.

Defibulators

A heart defibulator will help restore the natural rhythm of the heart when a person is experiencing cardiac arrest. The heart has a natural defibulator built in that acts much the way a pacemaker does, but as we age it can stop functioning properly (hence the cardiac arrest).