Heart and Blood Conditions
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 electrical pathway.
The heart has 4 chambers that work like a pump. The atria are the 2 top chambers. They receive blood from the lungs and the rest of the body. The ventricles are the 2 bottom chambers. They pump blood out to the lungs and the rest of the body. It is important for all 4 chambers of the heart to work together with one another to create an effective pump.
A group of cells called the sinus node is located at the top of the right atrium. This 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, fear or excitement.
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. Normally, the only way for signals to pass from atria to the ventricles is through the AV node.
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 extra (accessory) pathway.
Wolff-Parkinson-White Syndrome in Children
WPW may lead to 2 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 move 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 extra (accessory) pathway is typically present at birth. Some children with WPW begin having symptoms shortly after birth or in early childhood. Other children with WPW may never have symptoms or develop them later in childhood or even as adults.
About 10% to 20% 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 years of experience providing the treatment these children may require through our Arrhythmia Program. Some children do not require any treatment, but many will have treatment to cure their WPW syndrome. The Arrhythmia Program provides a full range of services for treating heart rhythm problems, including radiofrequency ablation and cryoablation, pacemaker or defibrillator implantation and surgery. In many cases, we can provide treatment for WPW with minimal or zero-radiation ablation. 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 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 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.
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 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.
Contact the Heart Center at 206-987-2015 for a cardiac referral, a second opinion or more information.