Wolff-Parkinson-White Syndrome

Overview

Wolff-Parkinson-White (WPW) syndrome is a heart rhythm disorder caused by an extra electrical pathway in the heart that has been present since birth. Normally, electrical signals between the upper chambers of the heart (atria) and the lower chambers (ventricles) travel through a single pathway. In WPW, there is an additional side pathway alongside this normal route.

This extra electrical pathway can cause the heart to beat very rapidly. Electrical signals create a loop between the normal pathway and the side pathway, suddenly accelerating the heart rate. This is called supraventricular tachycardia. When the heart beats very fast, palpitations, dizziness, shortness of breath, and sometimes fainting can occur.

WPW syndrome can appear at any age. In some people it causes no symptoms at all and is discovered only by chance on a routine electrocardiogram (ECG). In others, episodes of palpitations begin during childhood or young adulthood.

WPW syndrome is usually not dangerous. Rarely, however, it can lead to serious rhythm disturbances. With modern treatment methods, the condition can be permanently corrected and most people live normal lives.

Symptoms

The symptoms of WPW syndrome vary greatly from person to person. Some people have no symptoms at all, while in others the symptoms are very noticeable.

The most common symptoms are:

• Heart palpitations. The most noticeable symptom is the heart suddenly beginning to beat very rapidly and regularly. An episode of palpitations can last minutes or hours. The person feels their heart racing or fluttering in the chest.
• Dizziness or lightheadedness. When the heart beats very fast, the brain may not receive enough blood. This leads to dizziness and a sense of unsteadiness.
• Shortness of breath. During a rapid heartbeat, breathing can become difficult.
• Chest discomfort or pressure. During palpitations, a feeling of tightness or pressure in the chest may be felt.
• Fatigue and weakness. When the heart beats rapidly, the body becomes tired and a sense of weakness is felt.
• Fainting. When the heart rate rises very high, blood flow to the brain can drop significantly and the person may faint.
• Feeling of anxiety. During episodes of palpitations, feelings of worry and panic can develop.

Symptoms usually begin suddenly and stop suddenly. Episodes can last anywhere from a few seconds to several hours. In some people episodes are very rare, while in others they recur frequently.

When to See a Doctor

See a doctor in the following situations:

• If you regularly experience episodes of heart palpitations, having an evaluation is important.
• If chest pain, severe shortness of breath, or fainting develops during an episode of palpitations, go to the emergency room immediately.
• If you notice sudden episodes of palpitations in your child, difficulty feeding, rapid breathing, or pallor, see a pediatric cardiologist.
• If there is a family history of sudden cardiac death and you also experience palpitations, be sure to have an evaluation.

Causes

WPW syndrome is a structural difference that has been present since birth. During the development of the heart, an extra electrical pathway forms between the atria and ventricles. This side pathway conducts electrical signals in a way that differs from normal.

Why this extra pathway forms in some people is not fully understood. In most cases there is no hereditary cause and similar cases are not seen in the family. Rarely, however, WPW can show familial inheritance.

Some heart abnormalities can occur together with WPW. Ebstein's anomaly (a congenital heart valve problem) is particularly associated with WPW.

Complications

WPW syndrome does not cause serious problems in most people. In some cases, however, dangerous complications can develop.

• Atrial fibrillation. People with WPW have a higher than normal risk of developing atrial fibrillation (irregular and rapid electrical activity in the upper chambers of the heart). Atrial fibrillation on its own is usually not an emergency. When it occurs together with WPW syndrome, however, it can be very dangerous. The extra electrical pathway can conduct the rapid signals from atrial fibrillation directly to the ventricles. This can lead to a lethal rhythm disturbance called ventricular fibrillation.
• Ventricular fibrillation. Chaotic and ineffective electrical activity develops in the lower chambers of the heart. The heart stops pumping and sudden death can result. This risk is very low in WPW but is not zero. The risk increases when it occurs together with atrial fibrillation.
• Sudden cardiac arrest. Very rare but the most serious complication of WPW. The heart stops suddenly and unexpectedly. Without emergency intervention it can be fatal.
• Heart failure. Long-lasting and frequently recurring rapid heartbeat can rarely weaken the heart muscle and lead to heart failure.

The risk of these complications is not the same in every WPW patient. Risk factors include onset of symptoms at a young age, very rapid heart rate, and a family history of sudden death. Your doctor will assess your specific situation to determine whether you are in a risk group.

Diagnosis

WPW syndrome is usually diagnosed with an electrocardiogram (ECG). The ECG records electrical signals from the heart and shows the presence of the extra electrical pathway.

The diagnostic process typically includes:

• Electrocardiogram (ECG). This is the most important diagnostic tool. A characteristic finding called a delta wave is seen on the ECG. This finding indicates the presence of the extra electrical pathway. An ECG taken during an episode of palpitations directly shows the rhythm disturbance.
• Holter monitor. This is a portable ECG device worn for twenty-four hours or longer. If episodes are rare, it records heart rhythm during daily life and can capture episodes.
• Event recorder. This is a small device worn for weeks or months. When you feel palpitations, you activate the device and the heart rhythm at that moment is recorded.
• Electrophysiology study. This is an advanced test performed via cardiac catheterization. Special electrodes are placed inside the heart to map the electrical pathways. The exact location of the extra electrical pathway is determined and the rhythm disturbance is deliberately triggered for evaluation. This test can also be used for treatment purposes.
• Echocardiography. This images the structure of the heart using ultrasound. It is performed to investigate any accompanying heart abnormalities.

Treatment

The decision about treatment for WPW syndrome depends on the frequency and severity of symptoms and the person's age. If there are no symptoms, treatment may not be necessary. If symptoms are present or there is high risk, treatment is recommended.

Treatment options include:

• Observation. If there are no symptoms and the WPW finding on ECG was discovered by chance, monitoring alone may be appropriate in some cases. This decision, however, must be carefully evaluated by a cardiologist. If risk factors are present, treatment may be considered even if there are no symptoms.
• Vagal maneuvers. These are simple methods that can be applied during an episode of palpitations. Immersing your face in cold water, coughing, or bearing down while holding your breath stimulates the vagus nerve and can slow the heart rate. These methods can stop an episode but do not treat the condition.
• Medication. Medications can be used to control heart rhythm. Adenosine given intravenously can rapidly stop an episode. Medications such as beta blockers or calcium channel blockers can be used regularly to prevent episodes. Medication does not permanently correct the condition, however, and may require lifelong use. Important warning: If atrial fibrillation develops in WPW syndrome, some medications can be dangerous. Medications such as digoxin and verapamil should not be used in this situation.
• Catheter ablation. This is the most effective method for permanently treating WPW syndrome. A thin catheter is advanced to the heart through a blood vessel in the groin. A special energy source at the tip of the catheter (radiofrequency or cryoablation) destroys the extra electrical pathway. The procedure usually takes one to two hours and has a success rate above 95 percent. An overnight stay in the hospital may be required or discharge can happen the same day. After the procedure, most people recover completely and no longer need medication.
• Open heart surgery. In very rare cases, when catheter ablation is not possible or has been unsuccessful, the extra pathway is cut through open heart surgery. This method is rarely used today.

What to Do in an Emergency

During an episode of palpitations you can try the following:

• Perform vagal maneuvers. Bearing down while holding a deep breath, coughing, or splashing cold water on your face can stop the episode.
• Sit or lie down. Remaining standing increases the risk of fainting. Sit or lie down right away.
• Try to stay calm. Panic can increase the heart rate even further. Try to breathe slowly and deeply.
• Go to the emergency room. If the episode is prolonged, if there is chest pain, or if you are fainting, go to the emergency room immediately.

Living with WPW Syndrome

After catheter ablation, most people recover completely and continue their lives without any restrictions. If ablation has not been performed or if medication is being taken, certain points should be kept in mind.

If you have WPW syndrome, pay attention to the following:

• Have regular follow-up. Do not miss your cardiology appointments. The frequency and duration of episodes should be monitored.
• Use your medications regularly. If you are taking medication, use it regularly as your doctor recommends.
• Avoid triggers. Caffeine, alcohol, stimulant medications, and some cold medications can trigger palpitations. Learn which factors start episodes and avoid them.
• Consult about exercise. Most people can exercise safely. Before engaging in high-level competitive sports, however, consult your cardiologist.
• Inform if you are planning pregnancy. WPW syndrome usually does not cause problems during pregnancy. The medications you are using should be reviewed, however.
• Inform those close to you. Tell the people around you that you have WPW syndrome and what they should do during an episode.

Preparing for Your Appointment

What you can do:

• Note when episodes of palpitations started and how often they occur.
• How long did episodes last and how did they resolve?
• Did you notice any triggering factors?
• List all medications and supplements you are taking.
• Mention if there is a family history of heart disease or sudden death.
• Write your questions down in advance.

Questions you can ask your doctor:

• Is the diagnosis of WPW syndrome certain?
• What is the most appropriate treatment for me?
• How successful and risky is catheter ablation?
• What is my risk of developing atrial fibrillation?
• How long should I use medication?
• Can I exercise? Which sports are safe?
• I am planning pregnancy, what should I do?
• Should screening be done in my family?

Your doctor may ask you:

• When did episodes of palpitations begin?
• How long did episodes last?
• What triggers the episodes?
• Are there other symptoms during episodes?
• Have you fainted?
• Is there a family history of heart disease or sudden death?
• What medications are you taking?