Supraventricular Tachycardia in Children

Supraventricular tachycardia (SVT) is a type of abnormal heart rhythm in which the heart beats very quickly and then returns to normal. This can be frightening, but it is rarely dangerous. Episodes of SVT start suddenly and usually go away on their own.

This is the most common type of abnormal heart rhythm in children. Children with SVT usually do not have other heart problems. Most babies who have SVT outgrow it by the time they are one year old. Older children may need treatment if the episodes are frequent and cause symptoms.

What are the causes?

This condition is caused by abnormal electrical activity in the heart. The cause of this abnormal electrical activity is not known.

What increases the risk?

This condition is most likely to develop in:

• Children who drink sodas that contain caffeine.
• Children who take over-the-counter cough or cold medicines that contain a stimulant.

What are the signs or symptoms?

In some cases, there are no symptoms of this condition. If symptoms are present, they may be different in babies than in older children.

Symptoms of SVT in babies include:

• Poor feeding.
• Irritability.
• Rapid breathing.
• Full and throbbing veins in the neck.
• Being pale and sweaty.

Symptoms of SVT in older children include:

• Chest pain or a feeling of tightness in the chest.
• Feeling that the heart is skipping beats (palpitations) or beating very fast.
• Feeling dizzy, light-headed, or nauseous.
• Feeling tired and short of breath.
• Feeling anxious or frightened.
• Appearing pale and sweaty.
• Fainting.

How is this diagnosed?

This condition may be diagnosed based on:

• Your child’s symptoms. Your child’s health care provider may suspect SVT if your child has symptoms that start suddenly and then go away.
• A physical exam and medical history.
• An electrocardiogram (ECG). This is a test that records the electrical impulses of the heart.
• A Holter monitor or event monitor test. This test involves wearing a portable device that monitors the heart rate over time.
• An echocardiogram. This test uses sound waves (ultrasound) to produce images of the heart. This test can help to rule out other causes of a fast heart rate.

How is this treated?

Treatment for SVT depends on how severe your child’s condition is. Your child may need to see a heart specialist (cardiologist). If SVT episodes are infrequent or do not cause symptoms, your child may not need treatment.

If the episodes cause symptoms, your child’s health care provider may recommend vagus nerve stimulation. The vagus nerve runs from the chest, through the neck, to the lower part of the brain. The nerve controls some body functions, such as heart rate. Stimulating this nerve can slow down the heart. Your child’s health care provider can teach you and your child how to do this. Vagus nerve stimulation techniques include:

• Having your child blow against a sucked thumb without letting any air escape.
• Massaging one side of the neck just below the jaw.
• Massaging the eyes with eyes closed.
• Having your child bend over and cough.
• Splashing ice water on your child’s face.

If vagus nerve stimulation does not work, other treatments may be used, such as:

• Medicines to prevent the abnormal heart rhythm.
• Being treated in the hospital with medicines or electric shock to stop an attack (cardioversion). Treatment at the hospital may include:
  • Getting medicine through an IV.
  • Having a small electric shock delivered to the heart. Your child will be given medicine to sleep through this procedure.
• If your child is having frequent episodes with symptoms, he or she may need a long-term treatment to get rid of the faulty areas of the heart (radiofrequency ablation) and end episodes of SVT. In this procedure:
  • A thin tube (catheter) is passed through one of your child’s veins into his or her heart.
  • Energy is directed through the catheter to destroy (ablate) the areas of the heart that are causing problems.

Follow these instructions at home:

Medicines

• Give your child over-the-counter and prescription medicines only as told by your health care provider.
• If your child is taking medicines for SVT, ask your child’s health care provider what side effects to watch for.
• Check with your child’s health care provider before giving your child any new medicines, including supplements and over-the-counter cough or cold medicines.
• Do not give your child aspirin because it has been associated with Reye syndrome.

General instructions

• Do not let your child eat or drink anything that contains caffeine.
• Perform vagus nerve stimulation as directed by your child’s health care provider.
• Make sure that your child gets enough sleep and does not become overtired.
• Work closely with all of your child’s health care providers, including your child’s cardiologist.
• Keep all follow-up visits as told by your child’s health care providers. This is important.

Contact a health care provider if:

• Your child has side effects from medicines.
• Your child has symptoms of SVT that are lasting longer and becoming more frequent.
• Your child develops new symptoms along with other symptoms of SVT.
• Your child’s vagus nerve stimulation techniques no longer work or do not work as well as before.

Get help right away if:

• Your child has symptoms of SVT that do not go away after 20 minutes.
• Your child has trouble breathing.
• Your child has chest pain.
• Your child faints during an SVT attack.
• Your child’s skin, lips, or fingertips turn blue.

These symptoms may represent a serious problem that is an emergency. Do not wait to see if the symptoms will go away. Get medical help right away. Call your local emergency services (911 in the U.S.).

Summary

• Supraventricular tachycardia (SVT) is the most common type of abnormal heart rhythm in children. It can make a child’s heart beat very fast.
• Episodes of SVT start suddenly and usually go away on their own.
• SVT is caused by abnormal electrical activity in the heart.
• In some cases, there are no symptoms of this condition. If symptoms are present, they may be different in babies and in older children.