How Does a Defibrillator Work?

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Defibrillators are medical devices used to restore the heart’s regular rhythm. They work by delivering an electrical current or shock close to the heart to help the heart regain its normal beating pattern. There are different types of defibrillators that are either used in emergency settings or as a treatment to a chronic heart condition.

A common type of defibrillator is the Automated External Defibrillator or AED. This is a portable battery-powered device commonly found in public areas to be used in case of a medical emergency. In fact, many states have laws in place about the existence of AEDs in places such as schools, gyms, government buildings, etc. When someone shows signs of cardiac arrest, use of a defibrillator can help save the person’s life until medical personnel arrive. It has been estimated that quick use of an AED can increase chances of survival after cardiac arrest by 5-40%. AEDs come with detailed instructions so that even untrained individuals can assist with defibrillation. An AED will automatically analyze the person’s heartbeat pattern through sticky electrode pads applied on the chest and deliver a shock if deemed helpful.

Another type of defibrillator is the Implantable Cardioverter Defibrillator or ICD. ICDs are implanted under a person’s skin and track the heart rate. If an abnormality is detected, the ICD will deliver a shock at the right time, similarly to an AED. ICDs are used in patients with certain heart conditions who are at risk for dangerous heart rhythm abnormalities. Examples of such conditions are certain previous heart attacks, cardiomyopathies, and others.

More sources on defibrillators

  1. National Heart, Lung and Blood Institute. https://www.nhlbi.nih.gov/health-topics/defibrillators

  2. U.S. National Library of Medicine, MedlinePlus. https://medlineplus.gov/pacemakersandimplantabledefibrillators.html

  3. American Heart Association. https://www.heart.org/en/health-topics/arrhythmia/prevention–treatment-of-arrhythmia/living-with-your-implantable-cardioverter-defibrillator-icd

  4. American Red Cross. https://www.redcross.org/take-a-class/aed/using-an-aed

— Vicky Kanta