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Arrhythmias in Children

When the heart beats, electrical impulses travel through it. If these electrical impulses don’t work as they should, the heartbeat may be irregular. An irregular heartbeat is known as an arrhythmia. Arrhythmias can cause a heartbeat that is:

  • Too fast
  • Too slow
  • Unsteady or erratic

Pediatric Arrhythmia Causes and Risk Factors

Causes and risk factors for irregular heartbeats in children include:

  • Genetics: Some arrhythmias are inherited, or passed down through families. Children have a higher risk of an arrhythmia if the condition runs in their family.
  • Congenital heart defects: Certain congenital heart defects (present at birth) can disrupt the heart’s normal electrical pathways, leading to an arrhythmia.
  • Electrolyte imbalance: Electrolytes are minerals your body needs to keep a regular heart rate. If these minerals are out of balance, an arrhythmia can occur.

Arrhythmia Symptoms

Arrhythmia symptoms are different for each child. Some children don’t notice symptoms. Children and adolescents who have symptoms may experience:

  • Chest discomfort
  • Dizziness
  • Feeling like the heart “skipped a beat”
  • Feeling very tired after exercise
  • Heart fluttering
  • Palpitations (rapid, strong or irregular heartbeat)
  • Syncope (fainting)
  • Trouble breathing
  • Weakness

In newborns and infants, signs of an arrhythmia include:

  • Blue or gray skin color
  • Irritability
  • Rapid breathing
  • Feeding difficulties

Types of Pediatric Arrhythmias

Several types of arrhythmias may affect children. The types describe the specific rhythm abnormality or the part of the heart the arrhythmia affects.

Atrial fibrillation (AFib)

Atrial fibrillation is a quivery heartbeat. With AFib, electrical impulses fire from different parts of the heart. This causes the atria (top part of the heart) to shake, and it can’t pump blood as well.

AFib may affect children who have congenital heart defects or had previous heart surgery. Doctors can usually treat AFib with medications.

Atrial flutter

Atrial flutter is a type of tachycardia (fast heart rate). It happens when an electrical circuit in the atria is too fast. Atrial flutter is rare, but it can affect children who had previous heart surgery on the atria.

Children who have atrial flutter may have episodes of dizziness or fainting. It is generally not life-threatening, but severe cases may require treatment with medications or procedures.


Bradycardia is a heart rate that is too slow. It can range from mild to severe. Some children do not need treatment for bradycardia, but others benefit from an implanted pacemaker. This device can speed up the heart rate.

Complete heart block

Complete heart block happens when the heart’s electrical impulses cannot pass through the heart. Without these signals, the heart will still beat, but it will be slower than normal.

Some children are born with a type of heart block called congenital heart block. Others may develop complete heart block after cardiothoracic surgery or because of existing heart disease. Doctors may use a pacemaker to correct it.

Long QT syndrome (LQTS)

Long QT syndrome is a heart rhythm disorder that can cause a fast, erratic heart rate. The “QT” refers to an interval, or measurement, that doctors see on an electrocardiogram (EKG or ECG).

Some types of LQTS can cause serious complications without treatment. But doctors can use medications, a pacemaker or an implantable cardioverter defibrillator (ICD) to prevent these problems.

Sick sinus syndrome

The heart has its own pacemaker, which is known as a sinus node. The sinus node regulates the heartbeat with electrical impulses. Sick sinus syndrome happens when the heart’s sinus node doesn’t produce electrical impulses properly and is too slow (bradycardia).

Sick sinus syndrome can happen after open-heart surgery. Some children may need treatment with a pacemaker.

Supraventricular tachycardia (SVT)

Supraventricular tachycardia is a fast heart rate that occurs in the upper part of the heart. SVT can occur in newborns, children and adults. In some cases, fetal cardiology doctors can diagnose SVT before birth.

SVT is usually not life-threatening. It often disappears on its own in infants. Children and adolescents who have SVT may need medications or other treatment if symptoms are bothersome.

Ventricular tachycardia (VT)

Ventricular tachycardia is a fast heart rate in the lower chambers of the heart. With VT, the heart may not properly fill with blood. It can be life-threatening and may need immediate medical care. VT treatments include medications, ablation procedures (use heat or cold energy to eliminate the source of the arrythmia), implantation of an ICD, or surgery.

Wolff-Parkinson-White syndrome (WPW)

Children who have Wolff-Parkinson-White syndrome are born with an extra electrical pathway in the heart. This extra pathway can cause the electrical signals to misfire, making the heart rate too fast.

WPW can be life-threatening, and some children need treatment to avoid heart complications.

Arrhythmia Diagnosis

A pediatric electrophysiologist (heart rhythm specialist) may diagnose an arrhythmia with an electrocardiogram (EKG or ECG). This noninvasive, painless test measures the heart’s electrical activity.

In some cases, your child may need an exercise (stress) test. This test uses an EKG to show how your child’s heart responds to activity. If doctors need to see your child’s heart rate over several hours, your child may wear a Holter monitor, which is a small, portable EKG device.

Children who have inherited arrhythmias may benefit from a cardiogenomics expert. These specialists can diagnose inherited heart conditions and provide genetic counseling.

Arrhythmia Treatment

Doctors treat arrhythmias in many ways. Treatment depends on the type and severity of the arrhythmia. Common treatments include:

  • Medications: Some options include beta blockers or intravenous (IV) medications.
  • Cardioversion: Doctors use electricity to restore a normal heart rhythm.
  • Electrophysiology (EP) studies and ablation: EP studies can diagnose and correct arrhythmias without open surgery. Doctors use tiny instruments to treat the area of the heart that is causing the arrhythmia.
  • Implantable cardioverter defibrillator (ICD): An ICD is an implanted device that can correct a very fast or erratic heart rate.
  • Pacemaker: Pacemakers regulate a slow heart rate by prompting the heart to beat.

Arrhythmia Treatment at Children’s Hospital Los Angeles

Learn more about the arrhythmia treatment options we offer in our Electrophysiology Program.