Electrophysiology Study

What's it for?

An electrophysiology study (EP study) is an invasive test that uses 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 dysrhythmia)
  • Determine where in your heart the abnormal heart rhythm begins
  • Decide which treatment is best for your abnormal heart rhythm

What's it for?

Every beat of your heart is triggered by an electrical impulse. This impulse normally starts in a group of cells within your heart's right atrium (upper chamber), then travels through the rest of your heart in an organized fashion. A disruption anywhere along this electrical pathway causes an arrhythmia, or heart rhythm problem.

An electrophysiology (EP) study can be recommended to find out what is causing a heart rhythm problem. It is usually indicated when other types of testing or monitoring have not revealed the cause of your symptoms (palpitations, lightheadedness or fainting spells).

It can also be performed in situations to find out if one's heart may have the potential to develop risky or life-threatening heart rhythm problems. Although it is invasive and involves trying to trigger arrhythmias, the EP study provides information that makes it possible to:

  • Diagnose the source of arrhythmia symptoms
  • Predict the risk of a future cardiac event, such as sudden cardiac death
  • Assess the need for an implantable device (a pacemaker or a defibrillator) or treatment procedure (catheter ablation)
  • Evaluate the effectiveness of certain medications in controlling heart rhythm disorders

How it's done

At Lee Health, the EP study is performed at one of our two electrophysiology lab (EP labs). Typically, a patient comes to the electrophysiology lab the day the procedure is done. A nurse reviews the procedure with the patient, and that person is prepared for the procedure.

Patients are kept as comfortable as possible for an EP study. The procedure is performed with the assistance of sedation (either conscious, or short-acting, sedation administered through an IV, or less commonly, with general anesthesia). Some patients are awake enough to answer questions and watch the procedure on the monitors, but others may fall asleep. After the groin is numbed with local anesthetic, two or three catheters (narrow, flexible tubes) are inserted into the vein and then advanced to the heart.

Fluoroscopy (similar to x-ray) is used to guide the physician in advancing the catheters and provides real-time pictures of the catheters and heart. Once the catheters are in the heart, electrodes at the tips gather data, and numerous electrical measurements are made. Electrical signals may also be delivered through the catheters to trigger or induce a fast rhythm. Sometimes, medications are given to trigger a fast rhythm as well.

An EP study typically takes about a half to one hour. If further procedures are not indicated, the catheters are removed from the groin site, pressure is applied, and a band-aid is placed on the site. Patients are asked to lie flat for two hours following the procedure. Depending on the results of the EP study, patients may be able to go home the same day.


An electrophysiology study is considered a minimally invasive procedure. Even so, there are several risks that patients should know about:

  • Bleeding from the incision site
  • Damage to blood vessels by catheter
  • Blood clots
  • Worsened arrhythmia symptoms
  • Injury to the heart

Technology and expertise at Lee Health

Lee Health offers the most advanced and effective heart rhythm treatments to our patients. In 2011, Lee Health performed hundreds of electrophysiology procedures. We have two fully equipped electrophysiology labs and one dedicated implant room. They are staffed by nurses and technicians who work exclusively on heart rhythm disorders.

Who to contact

For questions related to cardiovascular care or services, email us at Hearts@leememorial.org