What is an AED (automated external defibrillator) analyzer?

What is an automated external defibrillator?

An automated external defibrillator (AED) is a portable automatic device used to restore normal heart rhythm to patients in cardiac arrest.

An AED is applied outside the body. It automatically analyzes the patient’s heart rhythm and advises the rescuer whether or not a shock is needed to restore a normal heart beat. If the patient’s heart resumes beating normally, the heart has been defibrillated.

When isit used?

An AED is used to treat cardiac arrest. It is a life-saving device because cardiac arrest is a sudden condition that is fatal if not treated within a few minutes.

Heart attacks and other conditions can cause ventricular fibrillation. In ventricular fibrillation, the electrical signals in the lower part of the heart are uncoordinated and ineffective. Very little blood is pumped from the heart to the body or the lungs. If ventricular fibrillation is not treated, it will result in Cardiac Arrest.

You can find AEDs in public places, such as airports and office buildings (public access AEDs). Doctors sometimes recommend home defibrillators for patients with heart disease.

How does it work?

An AED consists of a small computer (microprocessor), electrodes, and electrical circuitry. The electrodes collect information about the heart’s rhythm. The microprocessor interprets the rhythm.

If the heart is in ventricular fibrillation, the microprocessor recommends a defibrillating shock. The shock is delivered by adhesive electrode pads, through the victim’s chest wall, and into the heart.

There are special low-power electrode pads for use on children.

What will it accomplish? The AED delivers an electric shock that stuns the heart momentarily; stopping all activity. This gives the heart a chance to restart normal electrical activity and resume beating effectively.

When should it not be used?

The device should not be used in a patient who has a pulse. It should also be avoided under conditions where the patient cannot be isolated from other people (for example, in the standing water of a rowboat that is filled with passengers who are either touching the patient or the water).

Recently approved AEDs:

Find information about specific automated external defibrillators from FDA's Recently Approved Devices listings.

A bulge that weakens a part of the aorta, the main artery of the body. If untreated, it can burst. This results in death in nearly 80% of cases.

Angioplasty

A tiny balloon is passed into a blocked area of an artery. When the balloon is inflated, it presses the plaque that is causing the blockage against the blood vessel wall, freeing blood flow.

Arrhythmia

When the rhythm of the heartbeat is abnormal. Types include tachycardias (fast heart rhythms) and bradycardias (slow heart rhythms).

Arteries

Blood vessels that carry oxygen-rich blood to the different tissues of the body.

Atherosclerosis

A build-up of fat (cholesterol) within the artery wall. This build-up is sometimes referred to as "plaque." Plaque can block the artery and reduce blood flow.

Bradycardia (bradyarrhythmia)

An abnormally slow heartbeat, usually less than 60 beats per minute.

Coronary artery bypass graft (CABG)

An operation performed to get past blocked arteries of the heart and deliver blood to areas that aren't receiving enough.

Coronary artery disease (CAD)

A disease usually caused by atherosclerosis. CAD can cause less blood to be supplied to the heart.

Defibrillation

When a high-energy electrical impulse is used to stop fast, abnormal heartbeats. The shock restores the heart's normal rhythm.

Defibrillator

A device that monitors the heartbeat. It gives out a high-energy electrical impulse to stop very fast and abnormal heartbeats and returns the heart to a normal rhythm. It can be external (placed on the chest) or internal (surgically placed in the chest).

Fibrillation

When a heart chamber "quivers" due to an abnormally fast rhythm and can no longer pump blood well. Fibrillation of the atrium is called atrial fibrillation (AF); in the ventricle it is called ventricular fibrillation (VF). Ventricular fibrillation usually leads to death.

Heart attack

When a part of the heart muscle dies because blood flow is interrupted. Symptoms may include nausea, shortness of breath, and pain in the chest, arm, or neck. Also called "myocardial infarction."

Implantable cardioverter defibrillator (ICD)

A device placed in the chest that monitors the heartbeat (also known as an automatic implantable cardioverter defibrillator—AICD). When the heart beats too fast, the ICD delivers a high-energy electrical impulse to restore a regular heart rhythm. The ICD system usually consists of a pulse generator and one or more leads.

Leads

The wires that connect the pulse generator to the heart. They carry information on how the heart is beating to the pulse generator and carry electrical impulses from the generator to the heart. Leads are attached to the surface of the heart or passed into the heart through the veins.

Pacemaker/pacing system

A device that monitors the heartbeat. When it senses that the heart is beating too slowly, it sends an electrical impulse that stimulates the heart to beat faster. It includes a pulse generator (pacemaker) and one or two leads.

Pulse generator

The part of the pacemaker or defibrillator system where the electrical impulses are created.

Stent

A tiny metal tube that is put into an artery during an angioplasty. The stent holds the artery open and makes sure blood flows through the artery.

Sudden cardiac death (SCD)

When untreated electrical problems in the heart cause death. Sudden cardiac death is usually caused by heart rhythms that are too fast. This condition is also called "cardiac arrest." Sudden cardiac death is different from a heart attack, which is caused when blood flow is interrupted and the heart is damaged.

Tachycardia

An abnormally fast heartbeat, usually more than 100 beats per minute.

Ventricle

One of the two lower chambers of the heart. The right ventricle sends blood without oxygen to the lungs, and the left ventricle sends oxygen-rich blood to the rest of the body. The ventricles are the main pumping chambers of the heart and they contract at the same time.