An electrophysiology study (EP study) is a procedure that examines the heart’s electrical activity and pathways. An EP study can provide information about problems with your heart’s rhythm.

The Heart

© 2008 Nucleus Medical Art, Inc.

During an EP study, the heart’s electrical activity is studied from inside the heart. The study can help determine specifically what the rhythm problem is and what can be done to treat it.

EP studies are performed by an electrophysiologist, a specially trained cardiologist.

Reasons for Electrophysiology Study

An electrophysiology study is performed for the following reasons:

  • Diagnose the source of abnormally slow heart rhythms
  • Diagnose the source of abnormally fast heart rhythms
  • Provoke and diagnose heart arrhythmias that occur infrequently
  • Reveal suspected arrhythmias
  • Evaluate a person’s risk for sudden death
  • Assess a person’s response to anti-arrhythmic therapy or the need for a pacemaker or implantable cardioverter defibrillator
  • Assess symptoms of unknown cause, including:
    • Chest pain
    • Shortness of breath
    • Fatigue
    • Dizziness/fainting

Risk Factors and Possible Complications

The risk of complications during the procedure is low. A person’s risk is very individual and may relate to the specific arrhythmia suspected along with the underlying medical condition. Once you understand the risks, you will be asked to sign a consent form giving the electrophysiologist permission to perform the procedure.

Risks include:

  • Bleeding
  • Blood clots
  • Collapsed lung
  • Perforation of heart muscle or blood vessel
  • Stroke or heart attack (very rare)
  • Death (extremely rare)

Prior to Procedure

Follow your doctor’s instructions. Talk to your doctor about what medicines you’re taking. You may have to stop taking certain medications before the procedure. You will probably have blood tests, an electrocardiogram and a chest x-ray taken before the procedure. If your procedure will be done as an outpatient, make arrangements for a ride home.

During Procedure

You will be asked to lie down on the procedure table. Electrodes will be placed on your chest. The electrodes have wires that are hooked up to an electrocardiogram machine, which monitors your heart rhythm during the test. You will be shaved and cleansed around the area (usually the groin, neck, or just below the collarbone) where the thin tubes (catheter) will be inserted. You will receive a mild sedative through an intravenous line (IV) in your arm, which will help you to relax during the test.


A local anesthetic will be given by needle to numb the area around where the catheters will be inserted in the groin. If your study requires general anesthesia, your physician will discuss this with you prior to the procedure.

Description of the Procedure

Catheters will be gently threaded through the artery and into your heart with the help of x-rays on a television screen. Electrodes located at the end of the catheters send electrical signals to your heart to make it beat at different speeds. These electrodes also receive electrical signals from your heart, so that your heart rhythm can be recorded to assess the presence of abnormalities.

After Procedure

After the procedure, you will need to rest in bed until the sedative has worn off. Your heart rate and blood pressure will be monitored, and you will be checked for swelling or infections. You may be given pain medications, if necessary. After resting for at least 4-6 hours, your doctor will let you know if you can go home that day or if you need to be admitted for more treatment or observation. If you are discharged on the same day as the test, you should have someone drive you home.

How Long Will It Take?

The length of the test will vary based on what arrhythmia your doctor is investigating, and whether he or she needs to test your response to several medications. In general, the test may take two, four, or even more hours to complete.

Will It Hurt?

You may feel some mild discomfort with the initial injection. Also, as the doctors induce an arrhythmia, you may feel palpitations, shortness of breath, chest discomfort, or you may even lose consciousness. The medical team can usually control arrhythmias with medications, but they may need to administer an external shock to stop some rhythms. If they need to do this, you will receive more sedation.


The results of the study may be available before you leave the hospital, or in the next few days. Your doctor will notify you if you need any treatment.

Treating Abnormal Heart Rhythm

An EP study can help determine specifically what the rhythm problem is and what can be done to treat it. Depending on your particular rhythm problem, treatment options may include medications, catheter ablation or implantation of a device. Your physician will discuss the best treatment options with you.

Catheter Ablation

Catheter ablation destroys the abnormal electrical pathway or group of electrical cells that may be causing an arrhythmia. The procedure is often done during an electrophysiology study.

The catheter ablation procedure uses thin flexible wires called electrode catheters. These are inserted into the blood vessel in your groin or neck and passed to the heart. Once the problem area is identified using an electrophysiology study, the electrode catheter is moved to that area. Energy is sent to the catheter to destroy the problem cells.

Areas frequently treated with ablation:

  • An extra pathway of electrical cells
  • Abnormal tissue triggering a fast rhythm
  • Part of the AV node
  • All of the AV node with pacemaker implantation

After catheter ablation, the heart’s rhythm is tested again. One procedure is often successful in treating the arrhythmia.

Call Your Doctor If Any of the Following Occurs

  • Increased bleeding, bruising or pain at the insertion site
  • Shortness of breath or chest pain
  • Bruise or lump at the insertion site larger than a walnut
  • Fever over 100 degrees Fahrenheit
  • Symptoms of your arrhythmia

For more information, call (907) 264-2332