Electrophysiology Study and Catheter Ablation

An electrophysiology study and catheter ablation are procedures used to evaluate and treat children with cardiac arrhythmias, or abnormal heart rhythms. They involve the use of X-rays and are performed in a special hospital laboratory. An overnight stay in the hospital may be necessary.

Before the Procedure

The doctor will review your child's medical history and will explain the procedure in detail, including its benefits and potential risks. He or she also will discuss with you the kind of sedation that is likely needed for your child. On occasion, our doctors use general anesthesia. If anesthesia is used, you and your child will meet with an anesthesiologist before the procedure.

Be sure to ask any questions you may have. You will be asked to sign a written consent. It's standard hospital policy to perform a pregnancy test on all females over the age of 12 before exposing them to X-rays.

Aspirin and Medications

Please give your child aspirin every day, beginning three days before the ablation. Aspirin prevents blood from clotting too easily, making the ablation a safer procedure. Tylenol does not have this effect and can't be used in place of aspirin.

The dosage varies depending on your child's weight:

  • Children weighing less than 20 pounds should be given half of a baby aspirin tablet daily. Each whole tablet contains 80 milligrams. Give half of that, or 40 milligrams. Any brand is fine, including the flavored, chewable type.
  • Children weighing 20 to 40 pounds should be given one baby aspirin per day, or 80 milligrams.
  • Childen weighing more than 40 pounds but less than 80 pounds should be given two baby aspirins, each 80 milligrams, daily for a total daily dose of 160 milligrams.
  • Children weighing 80 pounds or more should be given one adult aspirin, 325 milligrams, per day. It's OK to crush the pill and mix it with food. Some brands are coated to make them easier to swallow.

If your child is allergic to aspirin or appears to have a cold, the flu or chicken pox, do not give your child aspirin. Instead, please call your child's doctor.

If your child is currently on medications for an abnormal heart rhythm, we will ask you to stop giving your child these medications three to five days before the procedure. Your doctor will discuss this with you.


Your child should not eat or drink anything for six to eight hours before the procedure. This usually means that your child should not eat or drink anything after midnight the night before the procedure.

During the Procedure

The procedure is performed in a room called an electrophysiology (EP) lab or catheterization (cath) lab. The lab is equipped with computers and monitors to record heart rate, blood pressure and oxygen levels. We use X-ray equipment to help us guide the catheters, which are thin flexible tubes, into the heart. The amount of X-ray exposure is usually very small.

Typically, the team includes one or two doctors, one or two nurses and a technician.

The day of the procedure, you and your child will either be sent to a hospital room or a waiting area before coming to the lab. During the procedure, we will provide you with a pager, in case we have any questions or we need to reach you.

At the start of the test, we may give your child sedation orally, to help your child relax. In addition, the doctor or nurse will insert a small tube, an intravenous or IV line, into your child's arm. We will use this IV to give sedation before and throughout the procedure to make sure your child is comfortable.

Once the monitors are applied and the sedation has taken effect, your child will lie comfortably on his or her back. The nurse will clean and, if necessary, shave the area where the catheters will be inserted. Catheters are most commonly inserted in the veins in the groin area and the neck. Catheters are the thin tubes that record electrical signals and help us to study the heart's electrical system and the abnormal heart rhythm.

Your child will be covered with a sterile sheet from chin to toe.

During the test, we will stimulate your child's heart to create the abnormal heart rhythm. With the use of catheters, we will locate the extra pathway or focus. This is called mapping. After a map has been completed, we are ready to perform an ablation.

During the ablation, we deliver radiofrequency (RF) energy through a catheter that is in contact with the extra pathway or focus. The tip of the catheter heats up and destroys the small area of extra electrical tissue.

After the Procedure

The EP study and ablation will take several hours. We will page you when we are finished and your child's doctor will meet with you to discuss the results of the procedure.

Your child will be transported to a room for four to six hours to allow the groin area to heal.

Many children are hungry after the procedure. When they are fully awake, they may drink liquids if they aren't nauseated. If liquid is tolerated, they may then eat.

Your child may notice some tenderness in his or her groin or neck once the local anesthetic has worn off. This can be treated with Tylenol or Motrin. There may be some bruising in the area, which will fade over the next few weeks.

Returning Home

Typically, your child will leave the hospital within 24 hours. Once home, most children return to full activity, including school, three to four days following the procedure.

Please call your child's doctor or nurse if you notice anything unusual after you return home. Please call immediately if your child experiences any of the following:

  • Dizziness or near-fainting
  • Rapid heartbeat. If this occurs, help your child to a relaxed lying position
  • Blood leaking from the groin or neck where catheters were placed. Apply very firm, steady pressure with the heel of your hand to the groin or with your fingertips to the neck

We don't expect problems. But if they do occur, please contact the UCSF Pediatric Heart Center.

Contact Us

If you have any questions, contact the UCSF Pediatric Heart Center at (415) 353-2008.


Reviewed by health care specialists at UCSF Benioff Children's Hospital.

Related Information

UCSF Clinics & Centers

Heart Center

Arrhythmia Center
1825 Fourth St., Sixth Floor
San Francisco, CA 94158
Phone: (415) 353-2008
Fax: (415) 353-2334

Interventional Cardiology Program
1975 Fourth St., Second Floor
San Francisco, CA 94158
Phone: (415) 353-4704
Fax: (415) 353-4144

Condition Information