Defibrillation can be a lifesaver for someone in cardiac arrest by using an electrical charge to stop your heart’s abnormal rhythm. This allows your heart to start a normal rhythm again. Defibrillation isn’t a guarantee of survival. Cardiac arrest is still fatal for many and survivors often need different types of therapy to recover.


Use of a defibrillator to restore a normal heart rhythm.
Getting your heart back to a normal rhythm with defibrillation.

What is defibrillation?

Defibrillation is the use of an electrical current to help your heart return to a normal rhythm when a potentially fatal arrhythmia (abnormal heart rhythm) is happening in your heart’s lower chambers (ventricles). Also known as electrical cardioversion, defibrillation is most effective when a healthcare provider delivers the shock as soon as possible after an arrhythmia starts.

Defibrillation can help with:


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Who needs to have defibrillation?

Someone with the specific types of arrhythmias named above may need defibrillation. If they’re in a hospital or a place that has an automated external defibrillator, someone can help them. But those who are at a high risk of a potentially fatal heart rhythm need to have a defibrillator on their person at all times.

Personal defibrillators

Shocks from personal defibrillators can range from painless to pain that feels like someone kicked your chest.

People at risk for a dangerous arrhythmia may use:

  • A vest-like wearable cardioverter defibrillator. You put this on under your clothes so the sensors touch your skin. They can detect an abnormal rhythm and send a shock when you need one.
  • An implantable cardioverter defibrillator (ICD) watches for arrhythmias and corrects them with the right amount of shock you need. While it’s similar to a pacemaker in its ability to keep your heart beating, a defibrillator has the added ability to provide a shock to the heart when a fatal rhythm is detected.

Why is defibrillation used?

Defibrillation gives you a chance to survive sudden cardiac arrest. You can give cardiopulmonary resuscitation (CPR) until someone can provide defibrillation. You can perform defibrillation even if the person has a pacemaker or an implantable cardioverter defibrillator (ICD).


How common is defibrillation?

Each year, more than 184,000 people outside of hospitals and about 200,000 people in hospitals experience cardiac arrest in the United States and may receive defibrillation.

Procedure Details

What happens before defibrillation?

Your first responder or healthcare provider will keep doing CPR until a defibrillator is ready and charged.

When they’re about to deliver the shock, they’ll make sure no one is touching the person receiving the shock (or their bed).

An automated external defibrillator (AED) — found in airports and other public places — can examine your heart’s rhythm to figure out if it’s the type of arrhythmia that needs a shock. It charges itself and then gives verbal instructions for using it.


What happens during defibrillation?

Your healthcare provider will follow these steps for a cardiac defibrillation procedure:

  • Place two defibrillator paddles or sticky pads (attached to the defibrillator) on your chest. One paddle or pad will go below your right shoulder and the other one below your left nipple. The pads have conducting material in them to prevent burns, but your provider will need to put conducting material on your chest before using the paddles.
  • For sticky pads, press a button on the defibrillator to release the charge. When using paddles, press the button on each paddle at the same time.

Defibrillation briefly stops your moving heart muscle to allow your heart to generate an electrical impulse and start a normal rhythm. In essence, defibrillation restarts the heart.

What happens after defibrillation?

Your provider will do CPR again for two minutes, check to see if you have a pulse and look to see if your heart rhythm is normal. If necessary, they’ll do more CPR and give you another shock. They’ll also give you medicines (epinephrine or amiodarone) if defibrillation didn’t work.

If you’re still unresponsive after your blood is moving again, you may need to have your body temperature cooled to 89.6 to 96.8 degrees Fahrenheit (32 to 36 degrees Celsius). Once you’re stable, you may need cardiac catheterization.

Risks / Benefits

What are the advantages of defibrillation?

Defibrillation can save your life if you receive it within the first 10 minutes of having ventricular fibrillation.

What are the risks or complications of defibrillation?

If you perform defibrillation on someone who doesn’t have ventricular tachycardia (with no pulse) or ventricular fibrillation, you may cause ventricular fibrillation and cardiac arrest.

Recovery and Outlook

What is the recovery time?

Recovering from cardiac arrest and defibrillation is a long-term effort of months or years for many survivors. After cardiac arrest, up to 40% of survivors have some level of impairment that keeps them from going back to work or doing regular daily activities when released from a hospital. Many survivors deal with fatigue. You also may need time to recover from a rib fracture from CPR and deal with other issues, like seizures or trouble walking. You may need occupational, physical and/or speech therapy.

When To Call the Doctor

When should I see my healthcare provider?

If you see someone collapse, call 911.

People who survive ventricular fibrillation are very likely to have it happen again. This is why your healthcare provider will treat the cause of your ventricular fibrillation and/or give you an ICD. You’ll need regular checkups to be sure your ICD is doing its job. It also needs a battery replacement after five years or so.

A note from Cleveland Clinic

If you’ve received defibrillation or have an ICD, keep taking medicines your healthcare provider prescribed for you. You’ll also need to visit your provider regularly to make sure your ICD is working right. If your defibrillation happened in an emergency situation, you may need months or years to get your body back to how it was. Getting physical therapy and other types of therapy can help you improve, but they take time and patience.

Medically Reviewed

Last reviewed on 05/10/2022.

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