Heart and Blood Conditions

Supraventricular Tachycardia

What Is Supraventricular Tachycardia?

Tachycardia is a fast heart rate. Supraventricular tachycardia (pronounced sue-prah-ven-TRIK-yu-lar tack-ih-CAR-dee-ah) (SVT) is one type of tachycardia.

There are four chambers in the heart - the top two are the  atria , and the lower two are the  ventricles . The heart uses a complex electrical system to make the muscle walls of the atria and ventricles pump blood.

The heartbeat is the squeezing and relaxing of the muscle walls at the right times in the right order. Normally, the heartbeat starts in the right atrium when a group of cells called the sinus node sends an electrical signal. This is the heart's pacemaker.

In SVT, the heartbeat comes from either an electrically overactive area of the atria or a "short circuit" of electricity involving the atria. Each of these causes an abnormally rapid heartbeat. SVT typically occurs in distinct episodes. How often these episodes occur and how long they last are different from one person to another.

Supraventricular Tachycardia in Children

SVT is the most common heart rhythm problem in children. It occurs in as many as one in 250 otherwise healthy children.

Sometimes SVT goes away on its own early in life. If SVT is active after the first year of life, the chance that it will go away on its own is low.

Brief episodes are generally well tolerated, meaning they don't bother the person much. But if the fast heartbeat continues too long, the heart can become fatigued, which can be dangerous.

Evaluation for a heart rhythm problem usually happens after the patient (or caregiver) notices a racing heart beat. There are many different causes of racing heartbeat. So it is important to have a heart doctor confirm the diagnosis of SVT and discuss treatment options.

Children with SVT don't always need treatment. In general, those with infrequent, well-tolerated SVT may simply be monitored. Those with more symptoms may take medications that can decrease the frequency of episodes. There are also procedures that, in most cases, can cure the rhythm problem.

Supraventricular Tachycardia at Seattle Children's

Our heart team has treated many children with SVT. We have extensive experience providing the treatment these patients require through our Arrhythmia Program .

When you come to Children's, a team of people will take care of your child. Along with your child's cardiologist, you are connected with pediatric electrophysiologists (heart rhythm specialists), child life specialists, social workers and others, if their expertise is needed. We work together to meet all of your child's health needs and help your family through this experience.

Since 1907, Children's has been treating children only. Our team members are trained in their fields and also in meeting the unique needs of children. For example, the doctors who give your child anesthesia are board certified in pediatric anesthesiology. This means they have extra years of training in how to take care of kids. Our child life specialists know how to help children understand their illnesses and treatments in ways that make sense for their age. Our expertise in pediatrics truly makes a difference for our patients and families.