Electrophysiology Study

Cardiac Electrophysiologic Studies (EPS)

An electrophysiology study (EPS) is one of the most accurate and reliable methods of evaluating heart rhythms. The procedure is performed by an electrophysiologist who will atttempt to reproduce your arrhythmia in a controlled environment and, through careful examination, determine its type and location in your heart. Most importantly, the EPS will help your physician determine the most effective treatment of your particular arrhythmia.

Prior to your EPS, you will undergo a series of tests, including blood tests and an electrocardiogram (ECG). These procedures may be performed on an inpatient or outpatient basis, depending on your particular circumstances. In some cases, you may be instructed not to take certain medications for two to three days before the EPS. Please consult with us a few days before the test to determine whether or not you should discontinue any of your usual medications. Your physician will discuss specific risks of the EPS and answer any questions you may have about the procedure.

Preparing You for the EPS Once You Arrive

The procedure is performed in a room with specialized diagnostic equipment and heart monitoring devices. In addition ot the electrophysiologist, a highly trained team of doctors and nurses will be present. You will be lying flat on a table during the procedure, which can last from two to six hours. You will remain conscious during the study, but the nurse will be giving your medication to help you relax.

Initially, the nurse wiil apply several ECG electrodes to your chest and then cover you with sterile sheets. It is important to keep your arms and hands under the sheets and remain on your back throughout the procedure because the area where the catheters are placed must remain sterile. After the sterile sheets are in place, the electrophysiologist will inject a local anesthetic (numbing medication) into your groin and/or neck where the electrode catheters (flexible wires) will be inserted. Some people will only have the catheters placed into the vein near the groin.

The anesthetic may cause a burning sensation, but it will soon numb the entire area. You should feel little discomfort while the catheters are being inserted. The electrophysiologist will use a fluoroscope which allows the physician to watch the catheters as they are guided through your veins/arteries into your heart.

During the Procedure

The catheters deliver tiny electrical impulses to "pace" your heart, triggering the same type of arrhythmia that you have been experiencing outside the hospital. During the pacing, you may feel your heart skip a beat or beat quickly. The catheters also record your heart's normal/abnormal electrical conduction. Thus, by placing the catheters in different areas of your heart, your physician can determine the location and type of the arrhythmia that your experience.

If the arrhythmia is produced during the study, you may feel the same symptoms you have experienced in the past. It is helpful to the medical team if you can describe your symptoms during the arrhythmia. It is important that you tell the physician or nurse immediately if you feel any palpitations, dizziness, shortness of breath or pain. Remember that you will be in an extremely controlled environment and a trained medical team is standing by to relieve your symptoms immediately, if necessary.

The arrhythmia may stop by itself, but if it persists, the electrophysiologist may try to "pace" your heart out of it by delivering electrical impulses to your heart. If a very fast arrhythmia is produced, patients my need to be "shocked" out of the abnormal heartbeat with a defibrillator--a machine that delivers an elecctrical shock through patches placed on the chest to restore the normal rhythm. Most patients do not feel discomfort from the "shock" because they often lose consciousness before the electrical shock is delivered as a result of inadequate pumping of blood to the brain during the fast heart rate.

If an arrhythmia can be triggered during your EPS, the electropysiologist my want to test a medication. After the medication is given to you intravenously, the electrophysiologist will try to reproduce your arrhythmia again. If the arrhythmia cannot be reproduced, the medication is deemed likely to be effective in controlling your arrhythmia. The procedure usually takes 1-2 hours.

After the Test

The cathethers will be removed after the EPS is completed and pressure will be applied to the insertion site for 15 minutes. You will be returned to your room, where you need to remain flat in bed for four hours following the procedure so that a clot can form at the catheter insertion site.

During this time, your blood pressure, pulse and groin site will be checked frequently by the nurse. You should keep your legs straight, as bending them can loosen the clot and cause bleeding. If you experience any numbness or tingling in your arms or legs, bleeding from the catheter insertion areas, chills, fever or chest pain, notify your nurse immediately. Patients are usually allowed to eat and drink following the procedure when lying flat in bed, but please check with your nurse.

When You Go Home

If you are able to go home after the procedure, please remember the following to ensure a quick recovery:

Stanford Medicine Resources:

Footer Links: