Heart and Blood Conditions

Wolff-Parkinson-White Syndrome

What Is Wolff-Parkinson-White Syndrome?

Wolff-Parkinson-White (WPW) is a condition in which the heart has an extra electrical pathway, also called an accessory pathway. Because of this extra pathway, electrical signals in the heart bypass the normal route of electricity.

The heart has four chambers that work like a pump. The  atria  are the two top chambers. They receive blood from the lungs and the rest of the body. The  ventricles  are the two bottom chambers. They pump blood out to the lungs and the rest of the body. It is important for all four chambers of the heart to work in sequence with one another to create an effective pump.

The sinus node is located at the top of the right atrium. This node is known as the "pacemaker" of the heart. It works to control the normal heart rate. It makes the heart beat slower during times of rest or sleep and beat faster with exercise or when you are scared or excited.

Each heartbeat begins with an electrical wave (signal) that passes from the sinus node through the atria. This signal travels through the atria much like the ripples created in water when a pebble is thrown in. This electrical signal makes the atria contract, or squeeze, making them beat.

Next, the electrical signal moves from the atria into the junction between the atria and ventricles. This junction is known as the atrioventricular node (AV node). The AV node delays the signal slightly, and then passes it on to the ventricles, making them beat.

After the ventricles beat, the heartbeat cycle is complete. The next heartbeat starts in the sinus node and follows the same path.

In children with WPW, electrical signals in the heart do not travel along the normal route because they have an accessory pathway.

Wolff-Parkinson-White Syndrome in Children

WPW may lead to two kinds of heart rhythm problems:

  • Supraventricular tachycardia (SVT) . Tachycardia (pronounced tack-ih-CARD-ee-ah) means the heart is beating too fast. SVT may require treatment. It is not usually life threatening.
  • Atrial fibrillation leading to ventricular fibrillation . Fibrillation (pronounced fib-rill-AY-shun) means very fast, irregular twitching of a muscle. Atrial fibrillation is rare in children. When it happens to someone without WPW, the normal route of electricity in the heart slows signals from the atria to the ventricles. This limits how quickly the ventricles beat. When it happens to someone with WPW, the accessory pathway can transfer fast, irregular signals from the atria directly to the ventricles. This can cause ventricular fibrillation, which is life threatening. This heart rhythm problem may need to be reset using a  defibrillator .

In WPW, the accessory pathway is typically present at birth. Some children with WPW begin having symptoms shortly after birth or in early childhood. Others may never have symptoms or develop them later in childhood or early adolescence.

About 10 to 20 percent of infants with WPW also have  congenital  heart disease, usually Ebstein's anomaly .

Wolff-Parkinson-White Syndrome at Seattle Children's

Our heart team has treated many children with WPW syndrome. We have extensive experience providing the treatment these patients may require through our Arrhythmia Program , including  radiofrequency ablationpacemaker  or  defibrillator  implantation, and  surgery . We also have a pediatric cardiac anesthesia team and a cardiac intensive care unit  to help care for children who undergo heart surgery.

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 nurses, 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.