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Cardioversion is a procedure to correct arrhythmias, which is when your heart beats too fast or irregularly. Arrhythmias may prevent your body from getting the blood and oxygen it needs. Cardioversion delivers a shock of electricity to your heart to help it return to its normal rhythm.


Before your procedure:

  • Informed consent is a legal document that explains the tests, treatments, or procedures that you may need. Informed consent means you understand what will be done and can make decisions about what you want. You give your permission when you sign the consent form. You can have someone sign this form for you if you are not able to sign it. You have the right to understand your medical care in words you know. Before you sign the consent form, understand the risks and benefits of what will be done. Make sure all your questions are answered.
  • An IV is a small tube placed in your vein that is used to give you medicine or liquids.
  • Heart monitor: This is also called an ECG or EKG. Sticky pads placed on your skin record your heart's electrical activity.
  • A pulse oximeter is a device that measures the amount of oxygen in your blood. A cord with a clip or sticky strip is placed on your finger, ear, or toe. The other end of the cord is hooked to a machine.
  • Oxygen: This may be given through a plastic mask or nasal cannula to help you breathe better. A nasal cannula is a pair of short, thin tubes that rest just inside your nose.
  • Medicines:
    • Blood thinners: This medicine helps prevent clots from forming in the blood. Blood thinners may be given before, during, and after a surgery or procedure. Blood thinners make it more likely for you to bleed or bruise. Use an electric razor and soft toothbrush to help prevent bleeding.
    • Heart medicine: This medicine is used to help make your heart more sensitive to the electrical charge so it responds to cardioversion.
  • Tests:
    • Blood tests: A sample of your blood may be sent to the lab for tests to find the cause of your symptoms. Blood tests may also be used to make sure organs, such as your liver and kidneys, are working correctly.
    • Transesophageal echocardiogram (TEE): This is a type of ultrasound that shows pictures of how your heart moves when it beats. It may also show blood clots in your heart. You will be given medicine to relax you during a TEE. Caregivers put a tube in your mouth that is moved down into your esophagus. The tube has a small ultrasound sensor on the end that lets caregivers check your heart.
  • General anesthesia will keep you asleep and free from pain during surgery. Anesthesia may be given through your IV. You may instead breathe it in through a mask or a tube placed down your throat. The tube may cause you to have a sore throat when you wake up.

During your procedure:

During cardioversion, your caregiver will send an electrical shock to your heart muscle. The shock is given at a certain time during your heartbeat that will best help it return to normal. You may need one of the following:

  • External cardioversion: This procedure uses paddles or gel pads to shock your heart. Two pads will be placed on your chest, or one will be on your chest and one on your back. Your caregiver will watch your heart beat on a monitor for the right time to deliver the shock. After the shock is given, your heartbeat will be checked. If your heart continues to beat abnormally, another shock will be given.
  • Internal cardioversion: This procedure uses catheters (thin, flexible tubes) that are put into your heart. Your caregiver inserts the catheters through a vein (blood vessel) and into your heart. Fluoroscopy (a type of x-ray) may be used to check the location of the catheter. The electric shock is then given through the catheters.

After your procedure:

You will be taken to a room where you can rest until you are fully awake. Do not get out of bed until your caregiver says it is okay. Caregivers will monitor your heart rhythm and watch you closely for any problems. When caregivers see that you are okay, you may be able to go home. If you are staying in the hospital, you will be taken back to your room.


  • The electric shock used may cause burns on your skin. If you have internal cardioversion, you may bleed or get an infection. Treatment may cause a blood clot to travel to your heart or brain and cause life-threatening problems, such as a heart attack or stroke. Even with cardioversion, your heart may not return to or stay in a normal heart rhythm. You may develop other arrhythmias that need treatment.
  • Without treatment, your arrhythmia and symptoms, such as chest pain and tightness, may get worse. You may have worsening weakness, dizziness, and trouble breathing. Arrhythmias that are not treated can increase your risk of heart failure or a heart attack. Arrhythmias also increase your risk for blood clots and a stroke. These conditions may be life-threatening.


You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Learn more about Cardioversion (Inpatient Care)

Micromedex® Care Notes