Electrophysiology Study


What is an electrophysiology study?

An electrophysiology study (EP study) is a detailed evaluation of the electrical activity in your heart. We use cardiac catheters and computers to create electrocardiogram (EKG) 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 doctor uses the EP study to:

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

Why do I need this test?

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

What are the risks?

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

Test Details

Should I take my medications?

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 have diabetes, check with your doctor about how to adjust your diabetes medication(s).

Can I eat?

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.

What should I wear?

  • 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.

What should I bring?

Bring a one-day supply of your prescription medications. Do not take these medications without first talking with the doctor or nurse. You may bring guided imagery tapes or music and the appropriate player.

Where is the procedure performed?

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

Will I be monitored?

Several monitors are used so your healthcare team can 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 (EKG): 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.

Will I be awake?

You’ll receive a medication through an IV (intravenous line) to help you relax and make you feel drowsy, but you will not be asleep during the test.

Preparing for the procedure

You will lie in a bed and your nurse will start an IV in a vein in your arm or hand. The IV 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.

What happens during the procedure?

The doctor will numb your groin with a special medication and then insert several catheters into the vein in your groin. The doctor uses the fluoroscopy machine, 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. 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.

How long does the procedure last?

The EP study takes two to four hours.

How do I care for the incision?

  • 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.

Will I need to stay in the hospital?

You will receive preliminary test results after the procedure. Based on these results, your doctor will determine if you are able to go home or will need to stay in the hospital.


  • Check with your doctor about which medications, if any, you should stop taking before the procedure.
  • Do not eat or drink anything after midnight before your test.
  • Wear comfortable clothes.
  • Do not bring valuables.
  • Bring a one-day supply of your medications.
  • Talk to your doctor or nurse if you have any questions or concerns about the procedure.


  • You will be closely monitored during the procedure.
  • Tell your doctor or nurse about any symptoms you have during the procedure.


  • You may need to stay in the hospital, depending on the preliminary test results.
  • Stay in bed for one to two hours after the procedure and keep your leg still.
  • Keep the incision area clean and dry.
  • Call your doctor if you have redness, swelling or drainage at the incision site.

Last reviewed by a Cleveland Clinic medical professional on 02/14/2019.

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