Wolff-Parkinson-White (WPW) syndrome

Overview

In Wolff-Parkinson-White (WPW) syndrome, an extra electrical pathway between your heart's upper and lower chambers causes a rapid heartbeat. The condition, which is present at birth, is fairly rare.

The episodes of fast heartbeats usually aren't life-threatening, but serious heart problems can occur. Treatment can stop or prevent episodes of fast heartbeats. A catheter-based procedure (ablation) can permanently correct the heart rhythm problems.

Most people with an extra electrical pathway have no fast heartbeat. This condition, called Wolff-Parkinson-White pattern, is discovered by chance during a heart exam.

Symptoms

Anyone, even babies, can have the symptoms of WPW syndrome, which result from changes in heart rhythm.

Common symptoms of WPW syndrome include:

• A rapid, fluttering or pounding heartbeat (palpitations)
• Dizziness or lightheadedness
• Shortness of breath
• Fatigue
• Anxiety
• Chest pain
• Difficulty breathing
• Fainting

An episode of a fast heartbeat can begin suddenly and last a few seconds or several hours. Episodes can occur during exercise or while at rest. Caffeine or other stimulants and alcohol trigger symptoms for some people.

Symptoms in infants

Signs and symptoms in infants with WPW syndrome can include:

• Grayish or blueish (ashen) skin color
• Restlessness or irritability
• Rapid breathing
• Poor eating

When to see a doctor

A number of conditions can cause irregular heartbeat (arrhythmia). It's important to get a prompt diagnosis and care. See your doctor if you or your child has symptoms of WPW syndrome.

Call 911 or your local emergency number if you have any of the following symptoms for more than a few minutes:

• Rapid or irregular heartbeat
• Difficulty breathing
• Chest pain

Causes

The extra electrical pathway that causes a rapid heartbeat is present at birth. An abnormal gene is the cause in a small percentage of people with WPW. The syndrome also is associated with some forms of congenital heart disease, such as Ebstein anomaly.

Otherwise, little is known about why the extra pathway develops.

Normal heart electrical system

Your heart is made up of four chambers — two upper chambers (atria) and two lower chambers (ventricles). The rhythm of your heart is normally controlled by a mass of tissue in the right atrium (sinus node). The sinus node produces electrical impulses, or signals, that cause each heartbeat.

These electrical signals travel across the atria, causing muscle contractions that pump blood into the ventricles. The signals then arrive at a cluster of cells called the atrioventricular (AV) node — usually the only pathway for signals to travel from the atria to the ventricles. The AV node slows the electrical signal before sending it to the ventricles.

This slight delay allows the ventricles to fill with blood. When the electrical signals reach the ventricles, muscle contractions pump blood to the lungs and the rest of the body.

Abnormal electrical system in WPW

In WPW syndrome, an extra electrical pathway connects the atria and ventricles, allowing electrical impulses to bypass the AV node. This detour activates the ventricles too early.

The extra pathway can also transmit electrical impulses from the ventricles back to the atria, disrupting the coordinated movement of the electrical signals through the heart, leading to changes in the heart rhythm.

The most common arrhythmia associated with WPW syndrome is called paroxysmal supraventricular tachycardia. Some people with WPW syndrome have a type of irregular heartbeat known as atrial fibrillation.

Complications

For many people, WPW syndrome doesn't cause serious problems. But complications can occur. It's not always possible to know your risk of serious heart-related events. If WPW syndrome is untreated — particularly if you have other heart conditions — you might have:

• Fainting spells
• Fast heartbeats
• Rarely, sudden cardiac arrest