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An electrophysiology study (EPS or EP study) is a test used to better understand the electrical system of the heart. Patients undergo an EPS for many reasons; they can have either fast or slow heart rhythm abnormalities (arrhythmias), have extra beats from either the upper chambers (atria) or lower chambers (ventricles) of the heart, have passing out episodes (syncope), or have episodes when they almost pass out (near-syncope).
The EP study is performed by a board certified physician trained in all aspects of arrhythmia recognition and management (electrophysiologist). This physician has performed hundreds of these tests on patients just like you.
You will be told not to eat or drink anything after midnight on the night before the procedure. Follow your physicians’ instructions for taking medications the morning of the EP study. You will also be required to have certain blood tests drawn at least a few days prior to the procedure. If you are of childbearing age a pregnancy test will also be performed to ensure that you are not pregnant.
After arriving at the electrophysiology laboratory, one of the nurses will assist you in changing into a hospital gown and will place an intravenous to assist us in administering sedation and medications during the procedure. Electrocardiogram electrodes and pads will be placed on your chest and back to monitor your heart rhythm throughout the study. You will be placed onto the procedure table lying flat on your back. You will notice a large camera and video monitors nearby. The x-ray camera will be used to view the location of the catheters that will be placed in your heart. The video monitors will also display the electrical signals recorded from within your heart. The area around both of your groins will be cleaned by the nurse. Your body will be covered with sterile sheets to prevent any infection during the procedure. The nurse will also administer some sedation through the intravenous to make you comfortable throughout the procedure.
The physician will inject a small amount of anesthetic into the skin in the groin area on both sides where the catheters will be placed to numb those regions. You might feel a pinch and some burning during this part of the case but otherwise you shouldn’t feel any other discomfort during the procedure. A small needle is then inserted into the vein and a wire is placed through the needle into the vein. The needle is removed and a small plastic tube (sheath) is placed into the vein over the wire. The wire is then removed and the sheath stays in place in the vein throughout the remainder of the procedure. This process is usually repeated for the vein on both sides. Small thin wires coated with plastic (catheters) that contain metal rings (electrodes) on them are then placed through the sheaths into the veins. Click here to see an image of an electrophysiology catheter. The physician then moves these catheters into the heart using x-ray guidance. These catheters allow electrical measurements to be made from inside the heart and stimulate the heart muscle.
The entire procedure can last anywhere from 1 hour to 4 hours depending on each particular case. You will be kept comfortable throughout the procedure. You may be awake during the procedure although many patients tend to sleep off and on throughout the procedure. The staff will constantly be monitoring your vital signs throughout the procedure. If you feel palpitations, chest discomfort, or dizzy at any point during the procedure you should tell the staff immediately. There is a good chance that an arrhythmia will be induced during the EP study. If this should occur and the arrhythmia does not stop on its own, the electrophysiologist can stop the arrhythmia and restore a normal rhythm with either rapid pacing via the catheters that are in your heart or with a shock to the heart.
After the procedure is completed, the catheters and sheaths will be removed from the veins and gentle pressure will be held over the veins for a few minutes to prevent any bleeding. You will be asked to lie almost flat for 3 to 4 hours after the procedure is finished to allow for the veins to heal.
The results of the procedure will be known immediately and will be discussed with you and your family soon after the procedure is finished. You might need to stay overnight in the hospital for a day or two and/or have other procedures depending on the results of the EP study.
You shouldn’t perform any heavy lifting or heavy physical exertion (including sexual intercourse, jogging, weight lifting) for at least 2-3 weeks after the EPS. Your physician can recommend which specific forms of exercise you will be allowed to perform. A small bruise (black and blue mark) or small lump can sometimes appear at the catheter insertion sites, which typically resolves over 2-3 weeks. A large lump or worsening pain at the catheter insertion site, swelling in the legs or fever should be reported to your doctor at once.
As with any invasive procedure, there are some risks involved in having an EP study. A small amount of bleeding or a localized infection at the catheter insertion sites is possible. Very serious side effects such as damage to the heart muscle wall or blood vessels, blood clots, stroke, and heart attack are rare. Death is very rare. The vast majority of patients undergoing an EP study do very well and do not experience any complications. You should speak with your physician regarding these risks and understand them prior to undergoing the study.