Wolff-Parkinson-White syndrome

Wolff-Parkinson-White syndrome (WPW) is most common in children who are born with a heart condition (congenital heart disease), but it can also occur in those without.

In the UK, between 1 and 3 people in every 1,000 are thought to have WPW syndrome

Most people experience symptoms between the ages of 30 and 40.

What happens?

WPW syndrome is a condition that makes the heart suddenly beat abnormally fast, in an abnormal heart rhythm called supraventricular tachycardia (SVT).

Episodes can last for seconds, minutes, hours or, in rare cases, days.

The frequency with which episodes occur can vary from person to person. Some people might have episodes on a daily basis, whereas others may only experience them occasionally.

Children with the syndrome will often report having symptoms such as:

• chest pain
• palpitations
• difficulty breathing

Adults often experience symptoms such as a:

• pounding heartbeat that occurs suddenly
• pulse that's too fast to count
• reduced ability to tolerate activity

In rare cases of WPW syndrome, a person's heart rate can increase significantly when a heart rhythm called atrial fibrillation occurs. The combination of the syndrome and atrial fibrillation can be life threatening and requires emergency assessment.

When the heart beats normally, its muscular walls contract (tighten and squeeze) to force blood out and around the body. They then relax, allowing the heart to fill with blood again.

In WPW syndrome, electrical signals in the heart can travel round and round in a loop, causing the heart to beat very fast. The heart muscle contracts at such a fast rate that it has very little time to relax and fill with blood inbetween contractions.

This reduces the amount of blood being pumped around the body, which can give the symptoms of dizzy or light-headedness, shortness of breath, and faintness or fainting.

If a person known to have WPW syndrome collapses or faints then this is an emergency, which requires a 999 ambulance call.

Someone with the syndrome may have heart palpitations, where the heart feels like it's pounding, fluttering or beating irregularly for a few seconds or minutes. They may not experience heart palpitations, and the syndrome may only be picked up if they have an electrocardiogram (ECG) for another reason.

The fast heart rate of Wolff-Parkinson-White (WPW) syndrome is caused by an extra electrical pathway in the heart.

This allows electrical signals to bypass the usual electrical system route and form a short circuit, resulting in an abnormally fast heart rhythm.

The extra electrical circuit is caused by a strand of muscle that grows from the atria to the ventricle when a foetus develops in the womb.

The syndrome rarely runs in families and usually occurs randomly in some babies.

If your GP thinks you might have Wolff-Parkinson-White (WPW) syndrome after assessing your symptoms, they'll probably recommend that you have an ECG and refer you to a cardiologist (heart specialist).

An ECG is a test that records your heart's rhythm and electrical activity. Small discs called electrodes are stuck on your arms, legs and chest and connected by wires to an ECG machine. The machine records the tiny electrical signals produced by your heart each time it beats.

If you have WPW syndrome, the ECG will record a "delta wave", which is an unusual wave pattern not usually present in people who don't have the condition.

Capturing an episode of a racing heart and palpitations using a normal ECG can often be difficult. This means that you might be asked to wear a small portable ECG recorder that will trace your heart rate continuously over 24 hours or when you switch it on at the start of an episode.

More about having an ECG

In many cases, episodes of abnormal heart activity associated with Wolff-Parkinson-White (WPW) syndrome are harmless, don't last long and settle down on their own without treatment.

You should go to your nearest hospital's accident and emergency (A&E) department if your heart beats abnormally fast for 20 minutes.

You'll be given an intravenous (through your vein) ‘drip’ to slow your heart rate down.

Medication

Anti-arrhythmic medicine or medication can often be used to prevent or manage a rapid heartbeat.

If medication proves ineffective, sometimes rebooting of the hearts electrical circuit is required and this is called electrical cardioversion.

Catheter ablation

The normal treatment for WPW is a catheter ablation. This is a procedure where the abnormal pathway is ablated (destroyed) using radio-frequency waves.