Electrophysiology Study

You may recently have been told that you have an arrhythmia, or abnormal heart rhythm. In some people, certain conditions can cause the heart to beat too slow, too fast, or in an unorganized fashion. These arrhythmias often produce symptoms such as palpitations, lightheadedness, or even loss of consciousness. Some can be life-threatening, and result in cardiac arrest. Your doctor can better assess your arrhythmia through the use of a specialized test called an electrophysiology study. Your doctor can then determine medications or treatments appropriate for you.

The electrophysiology (EP) study allows your doctor to measure the electrical activity of your heart, and in some cases, reproduce the arrhythmia in a safe, controlled environment.

The heart, which is a muscle, has an electrical system which is responsible for causing it to contract and relax. Each heartbeat is initially stimulated by a network of cells called the SA node, located in the upper right chamber of the heart. This is the natural pacemaker of the heart. The impulse then travels through the AV node, which separates the top and bottom chambers of the heart, and acts as a gate-keeper. From here, the impulse travels to a bundle of His, where it divides and travels down the right and left branches to stimulate the bottom chambers, or ventricles, to contract. This is responsible for the major pumping action of the heart, supplying blood to all the cells of the body. An arrhythmia results from a disturbance in one or more of these areas, and can therefore impair delivery of blood to the tissues of the body.

Preparation
The EP study is performed in the EP lab, which is staffed by skilled nurses and technicians.

Your doctor may require that you have some laboratory tests, an ECG (electrocardiogram) and a chest x-ray performed prior to the test. You can usually have these done as an outpatient. You should not have anything to eat or drink for at least six hours prior to the EP test. You may, however, take any medication you need with small sips of water. If you are currently taking any medications for arrhythmia, your doctor may require that you not take these drugs for approximately 72 hours before the test. Please discuss this with your doctor.

During the Procedure
Once in the EP lab, you will be placed on a heart monitor, and connected to an automatic blood pressure cuff. You may have a small device attached to your finger which allows the staff to continuously measure the oxygen level in your blood. You will be given some medication in your IV to help you to relax. It may also dull your memory of some events during the test. This is common and should not be a cause for concern.

Your groin area will be scrubbed with a special antiseptic solution, and draped with sterile towels. The doctor will then numb the groin area with a local anesthetic and small tubes called sheaths will be inserted, similar to starting an IV. Pacing wires are then guided through these sheaths, and positioned in various areas in the heart with the help of x-ray equipment. These wires are then connected to a large computer, which allows the doctor to make specific measurements of all parts of your heartÕs electrical system. This test takes approximately 1 to 3 hours to complete.

As previously mentioned, the doctor may be able to reproduce your arrhythmia. If this happens, the arrhythmia may terminate itself, or the doctor may have to restore a normal rhythm by using the wires to pace the heart. In some cases, an electrical shock, delivered through adhesive patches on your chest and back may be required to return the rhythm to normal. Your doctor will remain at your side throughout the entire procedure, and can answer any questions you may have at the time.

After the Procedure
After the procedure, the pacing wires and sheaths are removed from your groin, and a member of the staff will apply pressure to the site in order to allow the vessel to begin healing. You will return to your room, and must remain flat in bed for approx imately 4 to 6 hours. Your doctor will discuss your test results with you and your family sometime during this period. Your nurse will check your heart rate and blood pressure as well as assess your groin area frequently during this time. Please report any discomfort, swelling, or bleeding from the site immediately to your nurse.

Please do not hesitate to discuss any questions or concerns you have with your nurse or doctor.