(Also known as electrical cardioversion)


A cardioversion is a procedure that involves the delivery of a shock to your heart much like a defibrillator would. This procedure aims to restore your heart’s normal rhythm from an abnormal one.

Atrial fibrillation and atrial flutter are common rhythm disorders that may require cardioversion. Cardioversions may be used for patients who have supraventricular tachycardia or stable ventricular tachycardia.  Cardioversions are done at the Heart Institute in the Day Unit and are scheduled ahead of time by your doctor.


Electrical cardioversions are performed with anesthetic. An intravenous catheter will be inserted in your arm to deliver fluids and medication. Pads are placed on your chest and back and hooked up to an external defibrillator.

When the patient is asleep the physician delivers a shock. Usually, one shock is required. If the first shock does not work, the physician can try two to three more times with higher energy.  The cardioversion is over within a few minutes and the recovery time is quick.

Patient instructions

A week or so before your cardioversion, you will:

  • Have blood work and an electrocardiogram (ECG)
  • A transesophageal echocardiogram (TEE) may be advised to exclude blood clots in the atria. This is only necessary if you have not been stable on your blood thinner for more than four weeks.
  • If you are on an anticoagulant (blood thinner):
    • Coumadin : You will be required to have weekly INRs until the cardioversion to ensure your INR levels are within therapeutic range.
    • Apixaban, Rivaroxaban, Dabigatran, Edoxaban: You must be on treatment for at least four weeks. It is extremely important that you do not miss a dose.   

The night before the procedure, the Day Unit will call you to confirm that you are to arrive at the Heart Institute for 6:30 a.m. the morning of your cardioversion.

  • You should have nothing to eat or drink after midnight.
  • Unless otherwise specified by your physician, take your regularly scheduled medications the morning of the procedure with a sip of water.
  • Do not apply any lotion or ointments on your chest or back as this may interact with the stickiness of the cardioversion pads.

Before the procedure starts:

  • The physician will explain the risks and benefits and you will be asked to sign a consent form.
  • Please inform the doctor of any allergies you may have.
  • Ensure that body piercings on your chest or abdomen are removed prior to the cardioversion.

Inform the doctor if you are or think you may be pregnant.

Additional info

  • Minor skin irritation can occur at the site of the cardioversion pads.
  • After the procedure you should not operate a car, drink alcohol, operate heavy machinery or make any important decisions for 24 hours.  
  • We will not let you drive yourself home. You should arrange for a relative or friend to drive you home that day.
  • If you have sleep apnea, you will be monitored for four hours after your procedure.
  • Discuss your medications with your doctor or nurse as adjustments may have been made.

Patient Resources