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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:

  • Bring your medicine bottles or a list of your medicines when you see your caregiver. Tell your caregiver if you are allergic to any medicine. Tell your caregiver if you use any herbs, food supplements, or over-the-counter medicine.
  • Ask your caregiver if you need to stop using aspirin or any other prescribed or over-the-counter medicine before your procedure or surgery.
  • Blood thinners help 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.
  • You may need to have blood tests done before your procedure. You also may need a transesophageal echocardiogram (TEE) to check for blood clots in your heart. Ask your caregiver for more information about these and other tests that you may need. Write down the date, time, and location of each test.
  • Write down the correct date, time, and location of your procedure.

The night before your procedure:

  • Ask caregivers about directions for eating and drinking.

The day of your procedure:

  • Ask your caregiver before taking any medicine on the day of your procedure. These medicines include insulin, diabetic pills, high blood pressure pills, or heart pills. Bring a list of all the medicines you take, or your pill bottles, with you to the hospital.
  • You or a close family member will be asked to sign a legal document called a consent form. It gives caregivers permission to do the procedure or surgery. It also explains the problems that may happen, and your choices. Make sure all your questions are answered before you sign this form.
  • Caregivers may insert an intravenous tube (IV) into your vein. A vein in the arm is usually chosen. Through the IV tube, you may be given liquids and medicine.
  • Heart medicine may be used to help make your heart more sensitive to the electrical charge so it responds to the cardioversion.
  • An anesthesiologist will talk to you before your surgery. You may need medicine to keep you asleep or numb an area of your body during surgery. Tell caregivers if you or anyone in your family has had a problem with anesthesia in the past.


What will happen:

You may be given anesthesia medicine to help you stay asleep during the 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.


  • You cannot make it to your procedure.
  • You have a fever.

Seek Care Immediately if

  • You feel like your heart is fluttering or jumping in your chest.
  • You have discomfort in your chest that feels like squeezing, pressure, fullness, or pain.
  • You have pain or discomfort in your back, neck, jaw, stomach, or arm.
  • You have weakness or numbness in part of your body.
  • You have sudden trouble breathing.
  • You become confused or have difficulty speaking.
  • You have dizziness, a severe headache, or vision loss.


  • 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.

Care Agreement

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 (Precare)

Micromedex® Care Notes