Electrophysiology (EP) Study

Photo of EP Study

How to Prepare
What to Expect
What Happens Next


The electrophysiology (EP) study is a test used to evaluate heart rhythms from inside your heart. The EP study can do the following:

  • It tests your heart to see if you have a problem in the heart’s electrical system.
  • If you do have an electrical problem, it helps your healthcare provider choose the best treatment.

Arrhythmias may be difficult to diagnose. Symptoms may come and go. There may be no symptoms at all. Or, there may be symptoms that seem unrelated to the heart. An EP study focuses on problems of the electrical system of the heart that may cause symptoms.

The EP study is performed by a cardiac specialist called an electrophysiologist or EP. A family doctor or cardiologist may refer a patient with an arrhythmia for an EP study.


Learn More About Arrhythmias >>

How to Prepare

Your healthcare provider will give you specific instructions about preparing for your EP study. Follow the instructions carefully.

Your healthcare provider determines whether you should continue or stop certain medications, if you should avoid eating or drinking in the hours before the procedure and what to expect when you check into the hospital.

You may be admitted to the hospital the same day of the EP study and you may undergo preliminary blood tests, an X-ray, and ECG. You may go home that night or stay at the hospital overnight.

Tell your doctor if you:

  • Are allergic to seafood
  • Have had a bad reaction to contrast material or iodine in the past
  • Are taking Viagra
  • Might be pregnant

It is important for you to let the healthcare provider know all the medications you are taking. It is also important for your healthcare provider to know if you have allergies to any medications or to X-ray dye.

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What to Expect

Specially trained EP nurses and technicians work with your EP doctor as a team to provide care. On the day of the EP study you will be brought to the electrophysiology (EP) laboratory, a special room in the hospital with testing equipment and staff.

An intravenous (IV) line will be started in your arm and you will be given medicine to help you relax and get sleepy. This is called conscious sedation, which means you remain aware of your surroundings and are able to talk to the staff, but you should not feel any pain.

Your healthcare provider will clean, shave and numb the site where catheters will be inserted into your veins. This is typically done on the inside of one or both legs or your neck in order to access the heart.

Several thin tubes (catheters) are inserted into a vein in your leg, usually in your groin area (on the inside of your legs). Your doctor will gently push the catheters all the way into your heart.

An X-ray machine (fluoroscope) provides images of your heart during the procedure to help the doctor accurately position each catheter.

During the EP study, the doctor will use the catheters to create an electrical "map" of the heart. This is done by recording the electrical activity of the heart when the catheters are inside the heart.

If the EP study finds an arrhythmia, you may experience symptoms during this time, but otherwise you should be resting comfortably.

Remember that your doctor is trying to determine if a heart rhythm caused your symptoms. If the cause was an arrhythmia, and he creates it, you may experience some of the same symptoms that you felt before. These could include palpitations, light-headedness, or chest pain.

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What Happens Next

Your doctor will discuss the results of the EP study with you and your family. The electrophysiologist may wish to monitor your progress on medication, or conduct additional tests.

If the EP study produced an arrhythmia that caused the same symptoms you had before the study, the doctor will talk to you about treatment options, including medicine, cardiac ablation or implanted device therapies.

Most people are able to leave the hospital the same day though in some cases an overnight stay may be necessary. You must have someone available to drive you home and stay with you that evening.

Recovery from an EP study is usually quick. Many people are able to resume most of their normal activities 24 hours after the procedure. As the insertion site heals, some people experience bruising and feel a small, hard lump. This is normal and will go away in a few days.

If any of the following are experienced, it is very important to call the healthcare provider.

  • Bleeding at the insertion site
  • Increased pain
  • Any complaint of chest pain
  • Shortness of breath
  • Feeling cold, have swelling, or numbness on the arm or leg of the insertion site
  • The bruising or lump at the insertion site gets larger
  • Fever over 100° F
  • Return of arrhythmia symptoms


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