Having Electrical Cardioversion

Cardioversion is a procedure that is done to return your heartbeat to a normal rhythm. It’s done when the heart is beating very fast or irregular. This is called an arrhythmia. During the procedure, an energy shock is sent to the heart to reset it to a normal rhythm. This is done with a small machine that sends electric shocks to electrode pads on your chest. 

Cardioversion is most often a scheduled procedure. But in some cases, it may be done as an emergency treatment. This is done if symptoms are severe. You will be given medicine to let you sleep through the procedure.

What to tell your healthcare provider

Tell your healthcare provider about all the medicines you take. This includes over-the-counter medicines such as ibuprofen. It also includes vitamins, herbs, and other supplements, and any recreational drug use.

Tests before your procedure

You may need blood tests before the procedure. This is to make sure the procedure is safe for you. Blood tests can also help identify causes for irregular heart rhythms such as abnormal levels of electrolytes and thyroid hormone levels. A cardioversion may not be successful if there are conditions that cause abnormal test results.


And you may have a transesophageal echocardiography test before the procedure. This test is a special kind of ultrasound. A thin, flexible tube is put down your throat and into your esophagus. There, the tube is close to your heart. It lets your healthcare provider see if you have any blood clots. Your cardioversion will be delayed if a clot is found.

Getting ready for your procedure

Talk with your healthcare provider about how to get ready for your procedure. Follow his or her instructions about what medicines to take before the procedure. This includes medicines that may prevent arrhythmias. Don’t stop taking any medicine unless your healthcare provider tells you to.

You’ll be at a higher risk for blood clots, so your healthcare provider may want you to take blood-thinner medicine. You may take this several weeks before and after the procedure.

Make sure to:

  • Ask a family member or friend to take you home from the hospital. You cannot drive yourself.

  • Don’t eat or drink after midnight the night before your surgery, unless your healthcare provider says it’s OK.

  • Remove any jewelry that goes around your neck or is on your chest.

  • Follow all other instructions from your healthcare provider.

You will be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully. Ask questions if something is not clear.

On the day of your procedure

Ask your healthcare provider about the details of your procedure. The procedure only takes a few minutes. It may be different when done as an emergency treatment. In general, you can expect the following:

  • The healthcare provider will stick soft electrode pads to your chest. He or she may also put them on your back. These areas of skin may be shaved. This is to help the electrode pads stick.

  • The healthcare provider will attach wires to the electrodes. The wires connect to a cardioversion machine.

  • You will get medicine through a vein in your arm. This is to make you fall asleep.

  • The cardioversion machine sends an energy shock to your heart. This should convert your heart back to a normal rhythm. You won’t feel any pain.

  • Your healthcare team will closely watch your heart rhythm. They will watch for any signs of problems.

  • When the procedure is done, you will wake up.

After your procedure

You will wake up 5 to 10 minutes after the procedure. You’ll be closely watched for signs of problems for several hours. You will likely go home the same day. You may feel sleepy for several hours because of the sedation. Your healthcare team will make sure it is safe for you to eat and drink and stand before you are able to go home. You will need to have a family member or friend drive you home. Your chest may be red or sore for a few days.

You may need to take blood-thinner medicine, such as warfarin, for several weeks after the procedure. Take this exactly as directed. You may also need to take a medicine to prevent arrhythmias. Take all your medicines exactly as directed.

Follow-up care

Follow up with your healthcare provider, or as advised. 

When to call your healthcare provider

Call your healthcare provider right away if you have any of these:

  • Trouble breathing or chest pain (call 911)

  • Skipped heartbeats

  • Rapid heartbeat

  • Dizziness

  • Fainting

  • If you have uncontrolled bleeding while taking blood thinner medicines