What is an Electrophysiology Study?

An electrophysiology study (also known as an EP test)is a special study of your heart’s conduction system. The purpose of this test is to be sure that your electrical system is functioning properly. This test also helps us determine if there is an abnormality in your heart’s electrical system, which may possibly cause your heart to beat very rapidly. In some patients who have experienced heart attacks, this test may help to assess whether or not an implantable defibrillator may be needed to prevent death due to cardiac arrest.

During an EP study, special wires, called catheters are placed into your veins (usually from the groin) and positioned into the heart. The wires are placed into your veins through special intravenous lines known as sheaths. You are given some local anesthetic so that this part of the procedure is more comfortable. In addition, you are given medications through your vein to make you sleepy. In fact, many patients sleep through their EP test. It is important to let your Electrophysiologist know if you have had any reactions or allergies to medications used for sedation or anesthesia.

In general, up to three catheters are used for a routine EP test. Sometimes it is necessary to place more than three catheters, and sometimes it is necessary to use a vein in your neck in order to accommodate all of the catheters.

What to Expect During an EP Test

Prior to your EP test, you will be asked to fast from midnight until after the test. When you arrive, you will be admitted to a hospital room. You will also return to this room after your test. When it is time to go for your test, you will be taken on a stretcher to the EP lab. You will meet several of the nurses and technicians at that time. You will be positioned on an X-ray table. The area where the catheters will be placed (usually the right groin) is thoroughly cleaned and shaved if necessary. You will be covered with sterile sheets. Your Electrophysiologist and the EP nurse will be wearing masks, sterile gowns and gloves in order to prevent infections. At that time, you will be given some medications to relax you and help you sleep. Your doctor will also inject a local anesthetic in order to numb the areas where the catheters will be inserted.

Once the catheters are positioned in the heart, the Electrophysiologist will spend the rest of the time recording your heart’s electrical activity and making measurements. You may feel your heart skipping beats and racing at times, since part of the test involves pacing your heart and causing extra beats. This part of the test is not painful. If a rapid heart rhythm is started, the Electrophysiologist can stop it either by using the catheters in your heart or by delivering an electric shock to your chest. In most cases, you won’t feel this because of the sedatives given during the test.

After the test is completed, the catheters are removed from your heart and the intravenous sheaths are taken out. It is necessary to hold some pressure on the insertion sites in order to stop the bleeding at these sites. You will be instructed not to move your leg for about 4 hours in order to let the area heal. This prevents bleeding.

Are There Risks Involved?

An EP study is an invasive heart test, and does carry some risk. In general, the risks are low compared to the benefits derived from performing the test. Your Electrophysiologist will discuss the risks with you in detail. One of the most common risks is mild bleeding or bruising where the catheters were inserted. In order to prevent this, we ask that you try not to move your legs for 4 hours after the study.