What is Wolff-Parkinson-White Syndrome?

Wolff-Parkinson-White (WPW) syndrome is a heart rhythm problem that causes a very fast heart rate. WPW is one type of supraventricular tachycardia called atrioventricular reciprocating tachycardia (AVRT).

With WPW, an extra electrical pathway links the upper chambers (atria) and lower chambers (ventricles) of the heart. In normal hearts, the only electrical connection between the atria and ventricles is through the AV node. The AV node helps control the heart beat. In WPW, the extra electrical pathway is called a bypass tract because it bypasses the AV node. So the AV node cannot control the heart beat, and so it beats very fast.

People with WPW can have a heart rate of 160 to 220 beats per minute. Also, they are more likely to have atrial fibrillation or atrial flutter. When they do, the electrical impulses can travel down the bypass tract and cause the heart to beat at rates of more than 250 to 300 times per minute. This may result in fainting (syncope) or cause sudden death.

What causes WPW?

Many experts believe that Wolff-Parkinson-White syndrome may in some cases be inherited.

If you have a first degree relative, which is a parent, brother, or sister, with this disorder and he or she has symptoms, talk with your doctor about your risk for this abnormal heart rhythm.

What are the symptoms?

Symptoms include the sense of feeling the heart beat rapidly (palpitations), lightheadedness, fainting, and dizziness.

Symptoms may start during the teen or young adult years.

How often a person has an episode of rapid heart rate varies. A person may have episodes of rapid heart rate once or twice a week, have rare episodes, or never have symptoms.

Episodes of WPW can trigger a life-threatening heart rhythm called ventricular fibrillation, although this is extremely rare. Your doctor may recommend that you wear a medical bracelet to alert medical professionals of your condition if you are at risk for ventricular fibrillation.

How is WPW diagnosed?

Doctors can often diagnose Wolff-Parkinson-White syndrome by using an electrocardiogram (EKG or ECG). On EKG in WPW, the electrical preexcitation of the ventricles can be seen as an abnormality on the EKG known as a delta wave. In some people who have WPW, the accessory pathway is "concealed" and cannot be seen on an EKG.

How is it treated?

Treatment for Wolff-Parkinson-White syndrome includes medicine to control or prevent rapid or irregular heart rates.

Catheter ablation, a nonsurgical procedure, might be used to stop the rhythm problem. This procedure can successfully eliminate WPW most of the time. There is a small risk of the arrhythmia recurring even after successful ablation of WPW. But a second session of catheter ablation is usually successful.