Arrhythmia in Children | Pediatrics


Arrhythmia in Children

An irregular heart rhythm isn’t always cause for concern. But for children who need treatment for arrhythmia, our pediatric cardiologists are here to help.

Medically reviewed by Jonathan Gil Dayan, M.D. on March 08, 2024.

Female health care provider listening to young boy’s heart with a stethoscope.

What Are Arrhythmias in Children?

An arrhythmia describes any type of irregular heart rate. It could be that your child’s heart is beating too fast, too slow, skipping beats or having extra beats.

Most arrhythmias are harmless, and many require no treatment. Yet an irregular heart rate can sometimes make it harder for the heart to effectively pump blood. In rare cases, arrhythmias can be dangerous.

If your child does need treatment for arrhythmia, the UC Davis Pediatric Heart Center offers a variety of therapies. Our pediatric cardiologists use the latest arrhythmia treatment methods to keep your child safe.  

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Types of Arrhythmias in Children

An arrhythmia can affect different areas of the heart. There are several types of arrhythmias that can happen in children, including:


With tachycardia, your child’s heart rate is too fast. There are several types of tachycardias, defined by where or how the irregularity starts.

Wolff-Parkinson-White Syndrome

This malfunction (usually present at birth) causes electrical signals between the heart’s upper and lower chambers to short-circuit. The result is a too-fast heart rate.

Long QT Syndrome

This results from the lower chamber of the heart not relaxing quickly enough after a contraction.

Sick Sinus Syndrome

In sick sinus syndrome, electrical misfires in the heart’s sinus node can lead to a too-fast or too-slow heart rate.

Heart Block

Blocked or delayed electrical signals in the heart’s chambers can slow your child’s heart rate.

Atrial Flutter

When the upper chambers (atria) of the heart contract too quickly, it causes a very fast heartbeat, called atrial flutter.


Symptoms of Arrhythmias in Children

In some cases, pediatric arrhythmias do not cause any symptoms. If your child does experience symptoms, they may vary depending on the type and severity of the arrhythmia.

Common Symptoms

Talk to your pediatrician if you or your child notice any of these possible signs of an arrhythmia:

  • Dizziness
  • Fatigue
  • Fluttery feeling in the chest
  • Irritability (especially in very young children)

Emergency Symptoms

In rare cases, an arrhythmia can be life-threatening. Seek immediate medical care if your child experiences: 

  • Chest pain
  • Fainting
  • Shortness of breath

Causes of Arrhythmias in Children

There are many factors that can lead to an irregular heart rate in children. Causes of arrhythmias may include:

Congenital Heart Defect

A congenital heart defect is a change to the heart’s structure present at birth. These changes can sometimes disrupt the heart’s function and cause an arrhythmia.

Electrical Signaling Problems

The heart’s electrical system is a complex circuit designed to keep the heart beating regularly. A problem with the electrical signals in the heart can cause it to beat too slowly, too quickly or erratically.

Electrolyte Imbalances

The body needs to maintain a balance of certain minerals called electrolytes. When electrolytes are out of balance, it can affect how the heart beats.

Inherited Conditions

Certain heart conditions can be passed to a child from their parents. These inherited conditions may increase the child’s risk of developing an arrhythmia.


Diagnosis of Arrhythmias in Children

Your child’s provider may notice an arrhythmia while listening to their heart during a routine exam. To help diagnose the type and severity of the arrhythmia, they may do other tests, including:

  • Blood tests to check for any electrolyte imbalances.
  • Echocardiogram to look for structural defects in the heart.
  • Electrocardiogram (ECG) to test the heart’s electrical activity.
  • Longer electrocardiographic monitoring can range from 24 hours to 30 days (or up to 3 years with implantable devices).

Treatments for Arrhythmias in Children

If your child’s arrhythmia doesn’t cause noticeable symptoms, it may not require treatment. For children whose symptoms interfere with everyday life and activities, the right treatment can help. Our pediatric cardiologists use advanced methods to treat arrhythmias safely and effectively.


Certain drugs can help regulate a too-fast, too-slow or erratic heart rate.


Our pediatric cardiac surgeons thread a small tube (catheter) into the heart muscle. They use that access to treat the area of the heart that is causing the arrhythmia.


This procedure treats children with a too-fast heartbeat. We use an electric current to help restore a normal heart rhythm.

Implantable Device

We can place a pacemaker or implantable defibrillator under your child’s skin to regulate their heart rate.

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