Electrophysiology Study of the Heart

What is an electrophysiology study?

An electrophysiology (EP) study is a test that may be done to find what is causing an abnormal heart rhythm.

Some abnormal rhythms are caused by problems in the heart's conduction system. The conduction system is made up of special cells linked together in pathways. These pathways carry the electrical impulse that causes the heart to beat and pump.

An EP study checks the heart's electrical function in several ways. It measures the speed of an electrical impulse traveling through the conduction system. It locates pathways that are in the wrong place. EPS also helps to identify many types of abnormal heart rhythms by trying to reproduce them. The test will help your healthcare provider understand if medicine, a pacemaker, or an implantable defibrillator will help your symptoms or reduce your risk of sudden cardiac death.

When is it used?

An EP study may be done if:

• You faint suddenly and your healthcare provider thinks it was caused by a problem with your heart.
• Your heart stops beating (cardiac arrest) when there is no evidence of heart damage.
• You have conduction pathways that are abnormal and cause very fast heart rates.

An EP study is also used to test the effectiveness of different treatments for an abnormal heart rhythm problem. Because the abnormal rhythm often can be reproduced by the test, different medicines can be tried during the test to see which medicines are most helpful.

How do I prepare for this test?

• If you are going home after the procedure, find someone to give you a ride.
• Some medicines (like aspirin) may increase your risk of bleeding during or after the procedure. Ask your healthcare provider if you need to avoid taking any medicine or supplements before the procedure.
• You may or may not need to take your regular medicines the day of the procedure, depending on what they are and when you need to take them. Tell your healthcare provider about all medicines and supplements that you take.
• Tell your provider if you have had any kidney problems or reactions to iodine-containing foods or chemicals, such as seafood or X-ray contrast dye.
• Follow the instructions your healthcare provider gives you. You may need to stop eating and drinking for several hours before the procedure to keep you from vomiting during the procedure.

What happens during the test?

This test is usually done at the hospital.

Before the test you will be given medicine to help you relax, but you will be awake during the test. You will also be given a shot of anesthetic to numb the area where the catheter will be inserted.

Your healthcare provider will put 1 or more catheters through your skin and into a blood vessel in your groin, arm, or neck. Catheters are very thin tubes) into one of the large veins in your body, usually in the groin. The catheters are passed through the blood vessels toward the heart. X-rays are used to follow the position of the catheters.

The catheters are attached to a device that measures the speed of electrical impulses inside your heart. With the measurements, your provider can find your heart's conduction pathways and check their condition. Your provider may try to reproduce the abnormal heart rhythm by sending an electrical charge through a catheter and then see which medicines help prevent abnormal rhythms.

At the end of the test, your healthcare provider will remove the catheter and put pressure on the area where the catheter was inserted (the puncture site) to control any bleeding.

The test may last an hour or more.

What happens after the procedure?

After the test you may stay in an observation area for at least a few hours to make sure the puncture site is not bleeding. Depending on your condition, you may need to stay in the hospital for 1 or more days.

Avoid any strenuous activity for the rest of the day to prevent bleeding. You may have a bruise near the puncture site and be uncomfortable for a few days.

Ask your healthcare provider:

• how and when you will hear your test results
• how long it will take to recover
• what activities you should avoid
• how to take care of yourself at home and when you can return to your normal activities
• what kind of symptoms or problems you should watch for and what to do if you have them

Make sure you know when you should come back for a checkup.

What are the risks of this test?

Your healthcare provider will explain the procedure and any risks. Some possible risks include:

• You may have bleeding where the catheter was put into your blood vessel.
• A heart rhythm problem sometimes starts during EPS that needs treatment with an electric shock across the chest. This treatment, called defibrillation, brings the heart rhythm back to normal. You will not feel any discomfort from the shock.
• If the catheter is placed in an artery, a blood clot could form around the catheter. A clot could block the artery.
• The catheter may damage an artery, for example, the vessel in the groin or arm where the catheter was inserted.
• In rare cases, you may have an allergic reaction to the drug used in the anesthesia.
• While not common, a heart attack or stroke might be triggered by the test.

There is risk with every treatment or procedure. Ask your healthcare provider how these risks apply to you. Be sure to discuss any other questions or concerns that you may have.