Exams and Treatments



Electrophysiology study


An electrophysiology study is an electrocardiogram conducted directly inside the heart using electrode-tipped catheters that are inserted through a vein in the groin. The heart's electrical circuit is analyzed through programmed stimulation. Medical staff can then record and perform a detailed analysis of the heart beat.

This exam determines whether a patient has arrhythmia, which is an abnormal or irregular heart beat. The test lets the electrophysiologist make the correct diagnosis, provides information on the location of the arrhythmia site, and guides the doctor in choosing an appropriate therapy:

  • Medication
  • Catheter ablation of the arrhythmia's site of origin 
  • Implantation of a pacemaker
  • Implantation of a cardioverter defibrillator

The entire procedure takes approximately one hour. However, patients may be hospitalized for a few days.


Note that some tests may be done during pre-admission

  • ECG
  • Blood tests
  • Urinalysis
  • Chest X-ray
  • Pregnancy tests in fertile women
  • Follow-up by a nurse
  • Follow-up by a doctor (explanations, risks and benefits and signature of consent form)
  • Take your usual medication according to your prescription
  • Be fasting from midnight the night before the exam, but note that this does not apply to medication (follow your doctor's instructions)
  • Shaving of the chest and groin area (to create a sterile area and better adherence for electrodes and dressings)
  • Shower with an antiseptic soap

Recommendations for your hospital stay:

Bring your:

  • Health insurance card.
  • Montreal Heart Institute (MHI) card.
  • An updated list of medications provided by your pharmacy.
  • Your medication (not all medications are available at the MHI).
  • Comfortable clothing: dressing gown, slippers, tissues, books, etc. However, do not bring jewellery, extra cash, credit cards or valuable objects.
  • If you have sleep apnea, bring a continuous positive airway pressure (CPAP) machine.

On the day of the procedure:

  • Remain fasting; however, this does not apply to certain medications.
  • An IV line is inserted into the arm. 
  • Take the time to go to the bathroom and put on a hospital gown. Remove your underwear.
  • You will be taken to the EPS room on a stretcher or in a wheelchair.

The procedure is conducted in the EPS room in an aseptic environment:

  • Patients lie down on their backs on the exam table.
  • Electrodes are placed on the chest for the external ECG.
  • A blood pressure cuff is placed around the arm.
  • Splints are placed around the arms and knees to remind the patient not to move. Do not hesitate to advise staff of any discomfort.
  • You may be given medication to help you relax.
  • The groin area is disinfected with a liquid antiseptic and then covered with a large sterile field.
  • The doctor applies a local anesthetic to the groin area.
  • Through an incision in either a vein or an artery, the doctor will insert a wire that will guide the insertion of the catheter. The doctor uses fluoroscopy (X-rays) to move the catheters to specific areas.
  • When everything is in place, the programmed stimulation begins and the heart's electrical activity is recorded. If the stimulation triggers an arrhythmia, the patient may feel the normal symptoms of this condition. If this happens, the doctor can re-establish a normal rhythm right away.
  • At the end of the study, the doctor will inform the patient of the results. If they are positive, the doctor will discuss appropriate treatment: medication, ablation, a pacemaker or an implantable cardioverter defibrillator. The doctor will most likely suggest proceeding immediately if the patient requires catheter ablation or the implantation of a pacemaker or cardioverter defibrillator. 
  • When the procedure is finished, the catheters are removed. The doctor applies pressure to the groin area to prevent bleeding. A compression dressing is applied. 
Follow-up and side effects 

When you go back to your room:

  • Remain lying down for approximately 4 to 24 hours, depending on your doctor's orders and keep your leg(s) still to avoid any bleeding or hematoma at the puncture site(s).
  • A heart monitor is set up.
  • The nurse regularly checks your vital signs (blood pressure, heart rate, breathing, temperature), your dressings, and your foot temperature and pulses to ensure that there is good circulation.
  • Eat a light meal shortly after you return to your room.
  • Each dressing is changed the night of or day after the procedure.
Adult Congenital Heart Disease Center

Recommendations for discharge:

  • Remove any adhesive bandages the day after the procedure.
  • Take a shower instead of a bath for the first 3 days following the procedure.
  • Avoid intense physical exercise or exertion during the first week.
  • You can go back to work or school according to your doctor's orders.
  • Driving a vehicle: 2 to 3 days after the procedure or according to your doctor's orders.
  • If you have pain, take 1 to 2 tablets of acetaminophen (Tylenol®) every 4 hours.
  • It is normal to have some bruising in the groin area.
  • Contact your doctor if:

-          The pain in your groin area gets worse and is not relieved by Tylenol® (acetaminophen).

-          You have a hematoma (edema or swelling) or if bleeding develops at the puncture site(s).

-          You have difficulty walking.

-          You experience shortness of breath, chest pain, dizziness or vertigo.

-          You have a temperature of 38 °C (100.4 °F) with chills.


Appointment: If required by the electrophysiologist, you will receive an outpatient appointment by mail.