Wolff-Parkinson-White syndrome (WPW) is a rare condition that can cause an arrhythmia, or irregular heartbeat, due to a heart abnormality that is present from birth. WPW frequently causes no symptoms, so many people with the syndrome never know they have it. However, WPW can cause serious, and potentially deadly, heart problems.

What Is Wolff-Parkinson-White Syndrome?

Wolff-Parkinson-White syndrome affects the way electricity runs through the heart. To understand WPW, it’s important to know a little about the different parts of the heart, including its electrical system.

The heart has four main chambers, or areas, where blood moves in and out. The two smaller chambers, called the left and right atria, are located in the upper part of the heart. The two biggest chambers, called the left and right ventricles, are directly below the atria in the bottom half of the heart. The ventricles are responsible for most of the heart’s pumping action. The heart beats, or contracts, in response to electrical impulses that originate in the heart’s natural pacemaker, the sinoatrial node. This node is located in the right atrium.

From there, in a normal heart, the electrical signals are carried to the atrioventricular node, which is between the atria and ventricles. Finally, electrical impulses follow nerves from the atrioventricular node to the ventricles. As these electrical impulses travel through the heart, they cause the atria and ventricles to contract in an organized and coordinated way that allows the heart to pump properly.

WPW occurs when the heart has abnormal electrical connections, called accessory pathways, that allow some electrical impulses to take a shortcut from the atria to the ventricles. This is called ventricular preexcitation or preexcitation syndrome. This abnormal conduction can cause the ventricles to contract too early and even carry the impulses backward to the atria.

This abnormal flow of electrical current can result in a very fast heart rate (tachycardia) called supraventricular tachycardia (SVT) because it originates in the atria. WPW can cause paroxysmal SVT — sudden, brief episodes of SVT. When the heart beats too fast or in a disorganized way, it does not pump blood as effectively, leading to a variety of symptoms.

What Causes Wolff-Parkinson-White Syndrome?

In most people with Wolff-Parkinson-White syndrome, it is not clear why these extra electrical pathways develop.

WPW occurs more often in men than women. Men are also more likely to have more than one accessory pathway. In some cases, WPW occurs along with congenital heart defects — heart abnormalities present from birth — such as Ebstein’s anomaly.

Very rarely, WPW is linked to specific genetic mutations. This type of WPW can run in families, being passed from parents to children.

Symptoms of Wolff-Parkinson-White Syndrome

Many people with WPW never develop an arrhythmia and never experience symptoms. In many cases, WPW is discovered during a routine electrocardiogram (ECG or EKG).

Symptoms of WPW can occur at any time from infancy to adulthood and can last from a few seconds to hours. Symptoms occur when the heart is experiencing an arrhythmia. WPW shares many symptoms commonly seen with other arrhythmias, including:

• Shortness of breath (dyspnea)
• Dizziness or lightheadedness
• Fainting (syncope)
• Heart palpitations (feeling your heart racing or pounding in your chest)
• Chest pain
• Anxiety

WPW can occur along with atrial fibrillation (very fast and disorganized atrial contractions) or atrial flutter (very fast but regular atrial contractions). The combination of SVT with atrial fibrillation or atrial flutter is dangerous, raising the risk of a deadly arrhythmia — ventricular fibrillation — which, rarely, can cause cardiac arrest.

WPW in Infants

Wolff-Parkinson-White syndrome is present at birth but usually does not cause symptoms in infants and young children. When it does appear in infants, WPW can cause different symptoms, including:

• A bluish or grayish tint to the skin
• Restlessness and irritability
• Fast breathing
• Poor feeding

WPW in children is associated with other congenital heart defects about 15 percent of the time.

How Is Wolff-Parkinson-White Syndrome Diagnosed?

WPW is primarily diagnosed using an electrocardiogram, which shows electrical activity in the heart. An ECG can be used to detect abnormal heart rhythms and abnormal conduction of electrical impulses, such as preexcitation.

Because WPW does not typically cause long-lasting arrhythmias, doctors sometimes use a Holter monitor to diagnose WPW and other arrhythmias. A Holter monitor is a wearable ECG device that continuously records electrical activity in the heart for 24 hours or more.

Alternatively, a cardiac event monitor may be used. This device is similar to a Holter monitor but records an ECG only when you turn it on — while experiencing symptoms like a fast heartbeat, for example.

In addition to ECG, doctors can use cardiac catheterization or electrical physiologic testing to diagnose WPW. During a cardiac catheterization, a long, thin tube is inserted through a vein in the groin or arm and placed in different locations of the heart, and a special instrument measures electrical activity. This procedure can identify the exact location of any abnormal electrical conduction pathways and can also be used to treat WPW.

Treatment of Wolff-Parkinson-White Syndrome

People with WPW have several treatment options, including observation, certain maneuvers, medication, cardioversion, and ablation.

Observation

WPW is sometimes discovered as an incidental finding in an otherwise healthy individual who has never had any symptoms. In this case, a person may not need treatment. Regular follow-up may be recommended to watch for symptoms and ECG changes.

Vagal Maneuvers

One of the initial treatments for supraventricular tachycardia from WPW requires performing vagal maneuvers. These actions can stimulate the vagus nerve, which is involved in controlling your heart rate, and help your heart return to a normal rhythm. Vagal maneuvers include:

• Coughing forcefully
• Holding your breath
• Performing the Valsalva maneuver — Pinching your nose, closing your mouth, and exhaling while bearing down
• Applying an ice pack or cold water to the face (especially for infants and young children)

If you have SVT, it is important to discuss these maneuvers with your doctor or another health care provider. Vagal maneuvers are not appropriate for everyone, depending on what other medical conditions are present.

Medication

Antiarrhythmic drugs can be used to treat WPW arrhythmias while they are happening. These episodes of SVT can be treated with injected drugs, such as adenosine. If that is not successful, other drugs such as verapamil (Calan) and metoprolol (Lopressor) may be given by a health care professional to slow the heart rate. Infants with symptomatic WPW are typically treated with medication until they are 1 year old, when most infants outgrow the disease.

Cardioversion

Cardioversion is the use of medication (chemical cardioversion) or an electric shock (electrical cardioversion) to correct an abnormal heart rhythm. Electrical cardioversion (under sedation) is typically used to treat SVT due to WPW when vagal maneuvers and antiarrhythmic medications fail to stop the arrhythmia.

Catheter Ablation

Ablation is the destruction of the abnormal electrical pathway causing WPW. A doctor uses a cardiac catheter to kill the cells with heat or cold at the precise location of the conduction abnormality. Sometimes surgical ablation may be performed. Ablation can be a permanent cure for WPW.

The Outlook for Wolff-Parkinson-White Syndrome

Wolff-Parkinson-White syndrome is relatively uncommon and often does not cause symptoms. Rarely, the syndrome can result in dangerous arrhythmias; sudden death from WPW complications is even rarer.

Many people will go their entire lives never knowing that they have WPW, because it does not always cause a rapid heartbeat or any other health problems. For people who develop symptomatic WPW, the condition can usually be treated or controlled using common medications and medical procedures.

WPW can become more complicated when other, more serious conditions are present but is still very treatable. Talking with a cardiologist (heart specialist) can help you better understand the likely course of the disease, but the general outlook for WPW is positive.

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