Skip to content

Synchronized Cardioversion for an Abnormal Heart Rhythm

Make an Appointment

This information was reviewed and approved by Raphael Sung, MD, FACC, FHRS (4/1/2018).

What is synchronized cardioversion?

Your doctor has suggested you have a procedure called synchronized cardioversion because of an abnormal heart rhythm. Synchronized cardioversion is a procedure where an electrical shock is used to reset the rhythm of your heart. The electrical shock is synchronized so it happens at the appropriate time during the heart beating cycle.

Sometimes a procedure called transesophageal echocardiogram (TEE) is done before synchronized cardioversion. Your doctor may recommend you have TEE before synchronized cardioversion as part of your evaluation at National Jewish Health. If this is done you will receive the Test Facts on TEE also.


How do you get ready for the procedure?

Before the procedure, your doctor will explain the procedure in detail, including possible complications and side effects. They will be available to answer any questions you may have.

  • Do not eat food or drink liquids for at least 6 to 8 hours before the test.

  • Avoid caffeine sources for 24 hours prior to this test. This includes coffee, decaffeinated coffee, tea, decaffeinated tea, herbal tea, soda pop and chocolate.

  • Take your oral medicines with a small sip of water. You may be asked to hold certain medication.

  • Bring your blood glucose monitor, test strips and medication if you have diabetes.

  • Please arrive 60 minutes before your test is scheduled.

  • Wear clothing you can remove from the waist up. You will be given a gown to wear.

  • Ask a companion (family member or friend) to pick you up after your procedure and take you home. You will not be able to drive or take a taxi home after the procedure because of the medicine you will be given to make you drowsy.


Where do I go to get this test done?

Check in at the main desk and they will direct you to the Minimally Invasive Diagnostic Center (MIDC) waiting area.


What is done during the synchronized cardioversion?

When you arrive the nurse will explain what will be done before, during and after the procedure. If you have any questions, please ask. An intravenous (IV) line will be inserted into a vein in your arm or hand so medicine can be delivered when needed.

The nurse will connect you to several monitors:

  • Electrocardiogram (ECG): Electrodes (small, flat, sticky patches) will be placed on your chest. The electrodes are attached to an electrocardiograph monitor (ECG) that charts your heart’s electrical activity. Hair on your chest may be shaved before the electrodes are applies to improve the contact between the skin and electrode.

  • Blood pressure monitor: A blood pressure cuff will be placed on your arm to monitor your blood pressure often throughout the test.

  • Oximeter: A small clip is placed on your finger. The device monitors the oxygen level of your blood. You will be given oxygen during the procedure.

You will be given medicine in your IV to help you relax and feel comfortable as possible during the procedure. You will also feel drowsy.

The doctor or nurse will apply electrodes to your chest. An electrical shock will be delivered to reset the rhythm of your heart. The electrical shock is synchronized so that it happens at the appropriate time during the heart beating cycle. It may take more than one shock to reset the rhythm of your heart. You will be monitored at all times by trained medical staff before, during and after the procedure.


What should you do after the test?

The medication you receive during the synchronized cardioversion makes you sleepy so plan to have someone drive you home when you are done. Do not drive or resume normal activities until 24 hours after the procedure.

A nurse from National Jewish Health will call you to see how you are doing about 24 hours after your procedure.


How long will the synchronized cardioversion take?

Plan on being at National Jewish Health for at least 4 to 6 hours, although sometimes people stay longer. The preparation will take about 1 hour. The synchronized cardioversion is often a very rapid procedure, and is often complete within 15 to 45 minutes. The recovery may take from 1 to 3 hours.  Rarely, an overnight stay at a nearby facility is required.