Electrophysiology (EP) Study: Before Your Procedure

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Location of catheter insertion sites on the body, with detail of catheter entering heart.

What is an EP study?

An electrophysiology (EP) study is a test to see if there is a problem with your heartbeat (heart rhythm). This test can also find out how to fix the problem. A procedure called catheter ablation is sometimes done at the same time to try to correct the problem.

The doctor puts thin tubes called catheters into blood vessels in your groin, arm, or neck. The tubes are guided to your heart. There is an electrode at the tip of each tube. The electrode helps the doctor find the problem areas.

If a problem can be fixed with ablation, then the doctor uses the electrode to send energy to destroy (ablate) the areas of heart tissue that are causing the problem. The areas that are destroyed are very tiny. They should not affect the heart's ability to do its job.

You may get medicine that relaxes you or puts you in a light sleep. Or you might be asleep during the procedure. The places where the catheters go in will be numb.

If you have an EP study only and you don't need more treatment, you may go home the same day. If you also have ablation, you may stay overnight in the hospital.

How do you prepare for the procedure?

Procedures can be stressful. This information will help you understand what you can expect. And it will help you safely prepare for your procedure.

Preparing for the procedure

  • Be sure you have someone to take you home. Anesthesia and pain medicine will make it unsafe for you to drive or get home on your own.
  • Understand exactly what procedure is planned, along with the risks, benefits, and other options.
  • Tell your doctor ALL the medicines, vitamins, supplements, and herbal remedies you take. Some may increase the risk of problems during your procedure. Your doctor will tell you if you should stop taking any of them before the procedure and how soon to do it.
  • If you take a medicine that prevents blood clots, your doctor may tell you to stop taking it before your procedure. Or your doctor may tell you to keep taking it. (These medicines include aspirin and other blood thinners.) Make sure that you understand exactly what your doctor wants you to do.
  • Make sure your doctor and the hospital have a copy of your advance directive. If you don't have one, you may want to prepare one. It lets others know your health care wishes. It's a good thing to have before any type of surgery or procedure.

What happens on the day of the procedure?

  • Follow the instructions exactly about when to stop eating and drinking. If you don't, your surgery may be canceled. If your doctor told you to take your medicines on the day of surgery, take them with only a sip of water.
  • Follow your doctor's instructions about when to bathe or shower before your surgery. Do not apply lotions, perfumes, deodorants, or nail polish.
  • Take off all jewelry and piercings. And take out contact lenses, if you wear them.

At the hospital or surgery center

  • Bring a picture ID.
  • You will be kept comfortable and safe by your anesthesia provider. The anesthesia may make you sleep. Or it may just numb the area being worked on.
  • This procedure can take 2 to 6 hours. In rare cases, it can take longer.
  • After the procedure, pressure may be applied to the areas where a catheter was put in a blood vessel. This will help prevent bleeding. A small device may also be used to close the blood vessel. You may have a bandage or a compression device on each catheter site.
  • Nurses will check your heart rate and blood pressure. The nurse will also check the catheter site for bleeding.
  • If the catheter was put in your groin, you will need to lie still and keep your leg straight for up to a few hours. The nurse may put a weighted bag on your leg to help you keep it still.
  • If the catheter was put in your neck or arm, you may be able to sit up right away. If it was in your arm, you will need to keep your arm still for at least 1 hour.
  • You may have a bruise or a small lump where the catheter was put in your blood vessel. This is normal and will go away.

When should you call your doctor?

  • You have questions or concerns.
  • You don't understand how to prepare for your procedure.
  • You become ill before the procedure (such as fever, flu, or a cold).
  • You need to reschedule or have changed your mind about having the procedure.

Where can you learn more?

Go to https://www.healthwise.net/patientEd

Enter C658 in the search box to learn more about "Electrophysiology (EP) Study: Before Your Procedure".

The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.