Arrhythmias in Children

What are arrhythmias in children?

An arrhythmia is an abnormal rhythm of the heart. In an arrhythmia, abnormal electrical signals through the heart muscle may cause the heart to beat too fast (tachycardia), too slow (bradycardia), or irregularly. When the heart doesn't beat normally, it isn't able to pump blood to the body as well. That means the brain, lungs, and other organs may not get enough blood. And the organs can't work as well and may become damaged.

Arrhythmias in children include:

  • Long-Q-T syndrome (LQTS). This is a condition passed from parents to children (inherited). It usually affects children and young adults. Many children have no symptoms, but fainting is common in those who do. It may also cause cardiac arrest

  • Premature atrial contraction (PAC) and premature ventricular contraction (PVC). PACs or PVCs are abnormal beats that start in the upper chambers of the heart (atria) or the lower chambers of the heart (ventricles). They are common in children and teens. Often, they are considered completely normal and harmless.

  • Sinus tachycardia. A fast heart rate that occurs with fever, excitement, and exercise. It is normal.

  • Supraventricular tachycardia (SVT), paroxysmal atrial tachycardia (PAT), or paroxysmal supraventricular tachycardia (PSVT). This is the most common tachycardia in children. An abnormal electric circuit or focal site in the atria can cause rapid heart rates. Treatment may be needed if it happens often or lasts long.

  • Wolff-Parkinson-White (WPW) syndrome. This is an abnormal electrical signal that gets to the ventricle over an extra electrical pathway. It's present since birth. A fast heart rate is a common symptom. Or a child may not have symptoms. Sudden cardiac death may rarely occur.

  • Ventricular tachycardia (VT). This is a potentially life-threatening arrhythmia. It may be from serious heart disease. It is caused by a very fast electrical signal from the ventricles. A child may feel weak, tired, dizzy, or may faint (syncope). He or she may also feel his or her heart beat (palpitations).

  • Sick sinus syndrome. The heart's natural pacemaker (sinus node) doesn't work as it should. This causes slow heart rates. . It may occur in children who have had open heart surgery. A child may not have symptoms. A child with symptoms may be tired or dizzy, or may faint.

  • Complete heart block. The electrical signal from the upper to lower chambers is blocked. The heart usually beats considerably more slowly. This problem may happen after heart surgery or be caused by heart disease. It may cause a child to faint.

What causes arrhythmias in a child?

The cause of an arrhythmia may be unknown. Some known causes in children include:

  • Heart problem that is present at birth (congenital)

  • Heart problem that is inherited

  • Infection

  • Abnormal levels of certain chemicals in the blood

  • Normal reaction to exercise, fever, or emotions

  • Changes in the structure of the heart

  • Electrical conduction abnormality

What are the symptoms of an arrhythmia in a child?

A child with an arrhythmia may not have any symptoms. For those who do, these are the most common symptoms:

  • Feeling weak

  • Feeling tired

  • Feeling like the heart is fluttering (heart palpitations)

  • Low blood pressure

  • Feeling dizzy

  • Fainting (syncope)

  • Not feeding or eating well

The symptoms of an arrhythmia may look like other health conditions or heart problems. Make sure your child sees his or her healthcare provider for a diagnosis.

How is an arrhythmia diagnosed in a child?

Your child's healthcare provider will ask about your child's health history and family history. He or she look for signs and symptoms of an arrhythmia. The provider will give your child an exam focusing on the heart. Your child may need to see a pediatric cardiologist. This is a doctor with special training to treat children with heart problems. Your child may need tests, including:

  • Electrocardiogram (ECG). This simple test measures the electrical activity of the heart. An ECG may show an arrhythmia. The test may be a:

    • Resting ECG. Your child will lie down while electrodes are connected to the ECG machine by wires. The ECG records the heart's electrical activity for a minute or so.

    • Stress test (exercise ECG). Your child is attached to the ECG machine as described above. He or she will walk on a treadmill or pedal a stationary bike while the ECG is recorded. This test is done to check the heart during exercise.


  • Holter monitoring. Your child will have his or her heart rhythm checked over 24 to 48 hours. A small portable monitor is worn while your child goes about his or her usual activities.

  • Electrophysiologic study (EPS). For this test, the doctor puts a small, thin tube (catheter) into a large blood vessel in an leg or arm. The doctor moves the catheter to your child's heart. This test can find out the type electrical signal causing the problem, and where the signal is.

  • Tilt table test. This test may be done if your child faints often. The test checks your child's heart rate and blood pressure as he or she changes position.

  • Echocardiography (echo). This test uses sound waves to make detailed pictures of your child's heart structure and function.

  • Implanted loop recorder. This heart monitoring device may be used when the doctor thinks your child is at high risk for arrhythmia and other testing has not given a straight-forward result. This test may only be used in children who are high risk. The device is put under the skin. Itis used for long-term monitoring

How is an arrhythmia treated in a child?

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is. Some children don't need treatment. If your child needs treatment, he or she will likely be cared for by a pediatric cardiologist. Treatment may include:

  • Medicines. Medicines can ease symptoms.

  • Radiofrequency ablation. This procedure uses a special catheter to destroy the tissue causing the abnormal electrical signals. 

  • Surgery. Surgery can stop an abnormal heart rhythm.

  • Pacemaker. An artificial pacemaker may be needed with some arrhythmias. The pacemaker is a small device that is put inside the abdomen or chest. It gives a small amount of electricity to the heart to keep it beating regularly. Your child may need this if he or she has a slow heart rate.

  • Implantable cardioverter defibrillator (ICD). This a device is put in the chest or abdomen. It automatically sends a shock to stop an abnormal and dangerous rhythm. Some ICDs also work as pacemakers.

  • Electrical cardioversion.  An electric shock is given. This briefly stops the abnormal electrical action in the heart. It "resets" the heart's normal pacemaker. The heart can then restart in a normal rhythm.

What are the possible complications of an arrhythmia in a child?

Complications can happen, depending on the type of arrhythmia and how serious it is. Complications may include:

  • Damage to the brain, kidneys, lungs, liver, or other organs

  • Heart failure

  • Blood clots. A blood clot in the brain may cause a stroke.

  • Sudden cardiac death

How can I help my child live with an arrhythmia?

Some arrhythmias don't cause any problems. Some are more serious. A child with a serious arrhythmia will need frequent checkups.

Talk with your child's healthcare provider about managing your child's arrhythmia. Your child may need regular tests. Or your child may not be able to take part in some sports or activities.

When should I call my child's healthcare provider?

Call your child's healthcare provider if your child has symptoms of an arrhythmia. These include:

  • Feeling weak or tired

  • Having heart palpitations

  • Feeling dizzy

  • Fainting (syncope)

  • Not feeding or eating well

Key points about arrhythmias in children

  • An arrhythmia is an abnormal heart rhythm. It may be a heart rate that is too fast, too slow, or irregular.

  • An arrhythmia may not cause any symptoms. Or an arrhythmia may cause moderate to very serious symptoms.

  • An arrhythmia may not need treatment. If treatment is given, your child may need medicine, radiofrequency ablation, a device, or surgery.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

  • Know the reason for the visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.

  • Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.

  • Ask if your child’s condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if your child does not take the medicine or have the test or procedure.

  • If your child has a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.