Why Do We Need a Defibrillator How Does It Work

Automated external defibrillators: Do you need an AED? An AED may save your life during cardiac arrest. Weigh the pros and cons to see if you should get one.

Defibrillation is a common treatment for life-threatening cardiac dysrhythmias and ventricular fibrillation. Defibrillation consists of delivering a therapeutic dose of electrical current to the heart with a device called a defibrillator. This depolarizes a critical mass of the heart muscle, terminates the dysrhythmia and allows normal sinus rhythm to be reestablished by the body's natural pacemaker, in the sinoatrial node of the heart.

Cardiac arrest usually occurs when your heart's electrical activity becomes disrupted and the heartbeat gets dangerously fast (ventricular tachycardia) or chaotic (ventricular fibrillation). Because of this chaotic, often irregular heart rhythm (arrhythmia), your heart stops beating effectively and can't adequately pump blood.

During cardiac arrest, your brain and other vital organs quickly become starved of blood and the life-sustaining oxygen and nutrients it carries. If you survive, you may have permanent damage to your brain and other organs. The sooner your heart's rhythm is restored the better.

Cardiopulmonary resuscitation (CPR) is a vital step in the lifesaving process. CPR can keep some blood flowing to your heart and brain for a short time.

But often only defibrillation can restore the heart's normal rhythm and ultimately save your life. This is especially true if you experience a type of abnormal heart rhythm known as ventricular fibrillation.