Electrophysiology Study

An electrophysiology (EP) study is an invasive heart test done through catheters placed in a large vein in your groin, arm, neck, or chest. It is done to evaluate the electrical conduction system of your heart. An EP study is done if other heart tests have not found or fully explained the cause of symptoms such as:

  • Dizziness or fainting.

  • A fast heart beat (tachycardia).

  • A slow heart beat (bradycardia).

If the cause of your symptoms is found during the EP study, your health care provider will discuss treatment options. Some treatment options that may be done to correct your symptoms can include:

  • Cardiac ablation. Cardiac ablation destroys a small area of heart tissue that may be causing a fast heart rate (tachycardia).

  • Implantable cardioverter defibrillator (ICD). An ICD can detect a fast or abnormal heart rate. When an abnormal rhythm is detected, the ICD shocks the heart to restore it to a normal heart rhythm.


  • Any allergies you have.

  • All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.

  • Previous problems you or members of your family have had with the use of anesthetics.

  • Any blood disorders you have.

  • Previous surgeries you have had.

  • Medical conditions you have.


Generally, this is a safe procedure. However, as with any procedure, complications can occur. Possible complications include:

  • A fast heart rate (tachycardia) that does not go away. This may require shocking your heart (cardioversion).

  • Bleeding or bruising from the catheter insertion sites.

  • Infection at the catheter insertion sites.

  • Temporary or permanent heart rhythm abnormalities.

  • Temporary changes in blood pressure.

  • Puncture (perforation) of the heart wall. This can cause bleeding between the heart and the sac that surrounds it (cardiac tamponade). This is a life-threatening condition which may require heart surgery.

  • Possible cardiac arrest or fatal heart arrhythmia.


  • Do not eat or drink before the EP study as instructed by your health care provider.

  • Be sure to urinate before the EP study.

  • If you are going home after the EP study, someone will need to drive you home and stay with you for 24 hours.


The EP study is performed in a catheterization laboratory. This is a room set up to do heart procedures.

  • You will be given medicine through an intravenous (IV) access to reduce discomfort and help you relax.

  • The area where the catheter will be inserted will be shaved as needed and cleansed. Sterile drapes will cover you. This will keep the area sterile.

  • Thin, flexible tubes (catheters) with an electrode tip will be inserted into a large vein. From there, the catheters are guided to the heart using a type of X-ray machine (fluoroscopy). Once in the heart, the catheters evaluate the electrical activity of your heart.

  • If you are awake during the EP study, you may feel dizzy or lightheaded. Your heart rate may temporarily increase or you may feel your heart beating hard. Tell your health care provider if you feel dizzy, nauseated, or have chest pain or pressure during the EP study.

  • When the EP study is done, the catheters are removed.

  • Firm pressure is applied to the insertion sites. This is done to prevent bleeding.


  • You will need to lie flat for a few hours or as told by your health care provider. You will need to keep your legs straight. Do not bend or cross your legs. This is done so the clot at the insertion does not break loose and cause bleeding.

  • If you took blood thinners before the EP study, ask your health care provider when you can start taking them again.