Catheter Ablation in the Heart Catheterization Lab

What is catheter ablation?

Catheter ablation is done in the cardiac (heart) catheterization laboratory to correct tachyarrhythmias.

Catheter Ablation
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Energy is delivered through a catheter inserted in the heart to eliminate an abnormal electrical pathway.

What are tachyarrhythmias?

Tachyarrhythmias (say: tack-ee-a-RITH-me-uz) are fast (racing) heartbeats that are abnormal. These rapid heart rates are caused by abnormal electrical circuits in the heart. Sometimes these arrhythmias are treated with medication, and sometimes they need to be treated with catheter ablation.

What is heart catheterization?

During heart catheterization, the doctor carefully puts a long, thin tube called a catheter into a vein or artery in your child’s neck or groin. The groin is the area at the top of the leg. Then, the catheter is threaded through the vein or artery to your child’s heart.

The doctor who does the procedure is a cardiologist, which means a doctor who works on the heart and blood vessels. This may not be your child's regular cardiologist.

To learn about heart catheterization, please see "Heart Catheterization: Getting Ready for the Procedure."

What happens during the procedure

The procedure is performed while your child is under a general anaesthetic. This means that your child will be asleep during the procedure. 

Finding the abnormal circuit

The doctor threads a special catheter through your child’s blood vessels to the heart. A special type of X-ray called fluoroscopy lets the doctor see where the catheter is located.

Electrical signals sent by the heart travel through the catheters. These signals give information about the heart’s electrical system. The doctor also uses the catheters to trigger the rapid heart rate. This helps the doctor find the abnormal area in the heart.

Destroying the abnormal circuit

After the cardiologist finds the circuit that causes your child’s heart to beat fast, he or she uses hot or cold temperature to get rid of the circuit. When the circuit is destroyed, the rapid heart rate should not happen any more.

There are small risks of complications from the procedure

Generally, heart catheterization is a fairly low-risk procedure, but it is not risk-free. The doctor will explain the risks of heart catheterization to you in more detail before you give your consent for the procedure. The most common risks with catheter ablation are as follows:

The catheter may break through a blood vessel

There is a very small risk that the catheter may break through a blood vessel or the heart wall. To reduce this risk, we use a type of X-ray called fluoroscopy to see where the catheter is at all times.

There is a small risk of new heart rhythm problems

Sometimes the procedure can interfere with the heart's electrical system and cause new problems with the heartbeat. If this occurs, your child's cardiologist will discuss it with you in more detail.

For general information about the risks of heart catheterization, please see "Heart Catheterization: Getting Ready for the Procedure."

The procedure will take 3 to 6 hours

The procedure lasts 3 to 6 hours. After the procedure, your child will go to the recovery room to wake up from the anaesthetic. Then your child will go back to the inpatient unit.

After the procedure

The cardiologist will let you know when your child can go home. Your child will probably need to stay in the hospital overnight after the procedure. Your child may have an echocardiogram or a Holter monitor test before he or she can go home.

For information on what to do after your child goes home, please see "Heart Catheterization: Caring for Your Child After the Procedure."

If your child has a racing heartbeat after the procedure, call the cardiologist

After the ablation, children often feel that their heart is about to race. This feeling is normal. It is caused by single early beats that may have started the heart racing before the procedure. However, these events should no longer cause the heart to race. If your child does have a racing heartbeat, call the cardiologist.

Coming back for a check-up

Your child will be given an appointment to see your regular cardiologist in the cardiac clinic 2 to 3 months after the procedure. At this time, your child will have an electrocardiogram (ECG).

Write the date and time of the appointment here:


Acetylsalicylic acid (ASA or Aspirin) to prevent blood clots

Your child may need to take ASA for 2 to 3 months after the procedure. This will help to prevent blood clots from forming in the area where the pathway was interrupted. The doctor or nurse will tell you how much ASA to give your child before your child goes home.

Write the instructions and dose here:


Stop giving the ASA​ and call your family doctor or paediatrician if:

  • your child has a cold or fever
  • your child is exposed to chickenpox

In general, you should give your child acetaminophen (Tylenol) for fever and colds, as directed by your doctor. The doctor will tell you when you can start the ASA again.

If your child starts bruising easily, call your family doctor or paediatrician.

Key points

  • Catheter ablation is a treatment for children with certain types of rapid heart rate. Hot or cold temperature is used to destroy abnormal electrical circuits in the heart and correct the problem.
  • There is a small risk that your child will have complications from the procedure. Your child’s doctor will explain the risks to you before the procedure.
  • Your child will need to have an anaesthetic. Your child will need to stay overnight in the hospital after the procedure.
  • Your child will need to take ASA to prevent blood clots after the procedure.

Robert Hamilton, MD, FRCPC

Susan Johnston,  RN, BScN

Carrie Morgan, RN, MN

Jennifer Kilburn, RN, MN

Cindy Wasyliw, RN, BNSc