Electrophysiology Study (EPS)

An electrophysiology study (EPS) is a detailed evaluation of the electrical activity in your heart.  Cardiac catheters and computers are used to create electrocardiogram (ECG) tracings and electrical measurements from inside your heart.

During the test, your cardiologist may safely reproduce your abnormal heart rhythm, then give you medications to see which one best controls the rhythm.

Your cardiologist uses the EP study to:

• Find out what is causing your abnormal heart rhythm (also called arrhythmia)
• Determine where in your heart the abnormal heart rhythm begins
• Decide which treatment is best for your abnormal heart rhythm

Your doctor may recommend an EP study when other tests, such as a standard ECG, Holter monitor, event recorder, stress test, echo or angiogram cannot provide enough information to thoroughly evaluate your abnormal heart rhythm.

The procedure is performed in an electrophysiology laboratory under controlled clinical circumstances. The procedure is performed by cardiologists and nurses who specialise in electrophysiology.

An EP study is generally a very safe procedure. However, as with any invasive procedure, there are risks. Special precautions are taken to decrease these risks. Please talk to your doctor about any concerns you may have about the risks and benefits of the procedure.

Ask your doctor which medications you should take. You may need to stop taking certain medications one to five days before your test. Do not stop taking any medication without consulting with your doctor. If you are diabetic, check with your doctor about how to adjust your diabetes medication(s).

Eat a normal meal the evening before your procedure. But, DO NOT eat, drink or chew anything after midnight before your procedure. This includes gum, mints, water, etc. If you must take medications, only take them with small sips of water. When brushing your teeth, do not swallow any water.

Wear comfortable clothes.

Remove all makeup and nail polish. Please leave all jewelry (including wedding rings), watches and valuables at home. The clothing you are wearing that morning will be returned to the person who accompanies you.

Your study will take place in a special room, called the EP laboratory.

Several monitors are used to check your heart rhythm and blood pressure throughout the procedure.

Monitors Used During the Procedure

1. Fluoroscopy: A large X-ray machine will be positioned above you to help the doctors see the catheters on an X-ray screen during the procedure.
2. Defibrillator/pacemaker/cardioverter: Attached to one sticky patch placed on the center of your back and one on your chest. This allows the doctor and nurse to pace your heart rate if it is too slow, or deliver energy to your heart if the rate is too fast.
3. Electrocardiogram (ECG): Attached to several sticky electrode patches placed on your chest, as well as inside your heart. Provides a picture on the monitors of the electrical impulses traveling through the heart.
4. Blood pressure monitor: Connected to a blood pressure cuff on your arm. Checks your blood pressure throughout the procedure.
5. Oximeter monitor: Attached to a small clip placed on your finger. Checks the oxygen level of your blood.

You’ll receive a medication through an IV (intravenous line) to help you relax and make you feel drowsy. Rarely the procedure will be performed under a general anaesthetic.

Preparing for the procedure

You will lie in a bed and your nurse will put a cannula in a vein in your arm or hand. The cannula is used to deliver medications and fluids during the procedure.

Your groin will be shaved and cleansed with an antiseptic solution. Sterile drapes are used to cover you, from your neck to your feet. A strap will be placed across your waist and arms to prevent your hands from coming in contact with the sterile field.

The cardiologist will numb your groin with a special medication and then insert several catheters into the vein in your groin. A fluoroscopy machine is used to guide the catheters to your heart.

The catheters sense the electrical activity in your heart and are used to evaluate your heart’s conduction system. The doctor will use a pacemaker to give the heart electrical impulses through one of the catheters to increase your heart rate. Medications may also be given which help to bring on your arrhythmia. You may feel your heart beating faster or stronger. Please tell your nurses and doctor about any symptoms you feel during the procedure.

If your arrhythmia occurs, your doctor may give you medications through your IV to test their effectiveness in controlling it. If needed, a small amount of energy may be delivered through the patches on your chest to bring your heart back into a normal rhythm.

The EP study usually takes around 1 hour. If a rhythm disturbance is found then ablation may be performed which will take a further 1 to 2 hours.

After the procedure, your doctor will remove the catheters from your groin and apply pressure to the site to prevent bleeding. You will need to stay in bed and keep your leg as still as possible for one to two hours.

You will not need stitches. The incision will be covered with a small sterile dressing that can be removed the next day. Keep the area clean and dry.

Contact your doctor if you have any redness, swelling or drainage near your incision. Your doctor will talk to you about resuming normal activities.

If an EPS is performed without ablation you can be discharged on the day of the procedure. If ablation is performed then you may be advised to stay in hospital overnight.