Medical Specialties: Cardiology, Emergency medicine, Internal medicine

Clinical Definition

A defibrillator is a medical device that can administer a therapeutic, electrical impulse to the myocardium of the heart. It is used to eradicate life-threatening arrhythmias and re-establish a normal contraction rhythm of the heart. 

In Our Own Words

A defibrillator is a device used to deliver an electrical shock to the heart in order to stop an abnormal heartbeat and restore a productive heart rhythm. A defibrillator may be used to treat situations where the heart is beating chaotically, or dangerously fast. It’s important to stop certain abnormal heart rhythms immediately because if the heart does not pump blood efficiently, brain damage or death can result.


Today, defibrillators come in many different forms. Some defibrillators are used externally, such as automated external defibrillators (AED), meaning the defibrillator is placed on the outside of the body on the chest. Others are sophisticated devices that are surgically implanted in the chest, can detect arrhythmias, and deliver shocks if needed. Such devices are an option for some people who have a history of certain heart problems.  

Relevant Conditions
Common Types
  • Automated external defibrillator (AED)
  • Implantable cardioverter defibrillator (ICD)
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  • American Heart Association. Defibrillation. Accessed July 2013
  • The Cleveland Clinic. Implantable Cardioverter Defibrillator. Accessed July 2013
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