Heart and Blood Conditions

Supraventricular Tachycardia

What is supraventricular tachycardia?

Supraventricular tachycardia (pronounced sue-prah-ven-TRIK-yu-lar tack-ih-CAR-dee-ah) is a problem with the heart’s electrical activity causing an irregular heart rhythm. Tachycardia is a broad term used to describe fast heart rates and rhythms. ( “Tachy” means fast and “cardia” means heart.)

There are four chambers in the heart — the top two are the atria, and the lower two are the ventricles. The heart uses an electrical system to make the muscle walls of the atria and ventricles pump blood, which you notice as your heartbeat.

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 rhythm monitor (pacemaker).

There are many different types of tachycardia. Sinus tachycardia is a normal increase in heart rate in response to activity (running or playing), fear or excitement. Supraventricular tachycardia (SVT) is one type of tachycardia.

In SVT, the heartbeat comes from either a faster beating (electrically overactive) area of the atria or a “short circuit” of electricity involving the atria. Each of these causes an overly fast heartbeat. SVT typically happens 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 1 in 250 otherwise healthy children.

Sometimes, SVT goes away on its own early in life. If your child has SVT after age 1, the chance that it will go away on its own is low.

Short episodes usually don’t bother the person much. But if the fast heartbeat continues too long, the heart can become fatigued, which can be dangerous.

Tests for a heart rhythm problem usually happen after your child (or a caregiver) notices a fast heartbeat. There are many different causes of a fast heartbeat. It is important to have a heart doctor (cardiologist) confirm the diagnosis of SVT and discuss treatment options.

Children with SVT don’t always need treatment. In general, those with SVT that doesn’t happen often and is well tolerated may simply need to be monitored. Those with more symptoms may take medicines 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 Seattle Children’s, a team of people will take care of your child. Along with your child’s heart doctor (cardiologist), you are connected with heart rhythm specialists (pediatric electrophysiologist), 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.

Seattle Children’s has been treating children since 1907. Our team members are trained in their fields and in meeting the unique needs of children. For example, the doctors who give your child anesthesia (sedation) are board certified in pediatric anesthesiology. This means they have extra years of training in how to help kids deal with their medical conditions. Our child life specialists know how to help children understand their illnesses and treatments in ways that make sense for their age.

Contact Us

Contact the Heart Center at 206-987-2015 for a cardiac referral, a second opinion or more information.