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Learning About Arrhythmias in Children

Electrical system of the heart

What is an arrhythmia?

An arrhythmia, or abnormal heartbeat, is a change in the normal rhythm of the heart. Your child's heart may beat too fast or too slow. Or it may beat with an irregular or skipping rhythm.

The heart has an electrical system that creates signals to make the heart pump. When something affects those signals, an abnormal heartbeat can occur. Some types of arrhythmias aren't a problem. But others are more serious and may need treatment.

What causes it?

Several things can cause an abnormal heartbeat. They include illness, a heart problem a child is born with, medicines, and heart surgery. Some arrhythmias may run in families. Sometimes the cause isn't known.

What are the symptoms?

Some children don't have symptoms from an abnormal heartbeat.

But an arrhythmia can cause many symptoms. Your child may:

  • Feel weak or tired.
  • Feel light-headed or dizzy.
  • Feel their heart beat fast or skip a beat.
  • Act cranky (in babies).
  • Have chest pain.
  • Pass out.

How is it diagnosed?

To diagnose an arrhythmia, the doctor will listen to your child's heart and ask about your child's symptoms. The doctor will also ask about any heart problems in your family. You may be asked to keep a diary of your child's symptoms.

Your child may have tests at the doctor's office. Or the doctor may want you to go to a specialist (pediatric cardiologist) for tests.

Tests that your child may have include:

An electrocardiogram (EKG or ECG).

This test measures the electrical signals that control the heart's rhythm. The EKG shows the heart's activity as line tracings.

An at-home heart monitor.

Your child might use a heart monitor at home. It may be worn or carried. The monitor records EKGs of your child's heart.

An electrophysiology study.

A doctor puts thin tubes called catheters into blood vessels and moves them to the heart. The catheters have electrodes at the tips. They give the doctor details about the heart's electrical activity.

How is it treated?

Some heart rhythm problems don't need treatment. Your doctor may watch your child over time to make sure that your child is doing well.

For more serious rhythm problems, treatment may include:


Certain medicines can slow down the heart if it's beating too fast. Other medicines can prevent an abnormal heartbeat from happening.

A pacemaker.

A pacemaker is a device that's placed under the skin and connected to the heart. It sends painless signals to help the heart beat normally.

An implantable cardioverter-defibrillator (ICD).

Like a pacemaker, an ICD is a device that's placed under the skin and connected to the heart. It uses electrical signals or a shock to stop a deadly heart rhythm.


This procedure uses a shock to help return the heart to a normal rhythm.

Catheter ablation.

A doctor puts thin tubes called catheters through a blood vessel and into the heart. Wires in the catheters use energy to destroy tiny areas of the heart that cause the abnormal heartbeat.


Sometimes surgery may be done. Heart tissue might be cut to try to stop the signals that cause the abnormal heartbeat.

Follow-up care is a key part of your child's treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if your child is having problems. It's also a good idea to know your child's test results and keep a list of the medicines your child takes.

Where can you learn more?

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