Wolff-Parkinson-White syndrome is a heart abnormality which can cause sudden death in rare cases.
The condition is present at birth, causing episodes of a racing heartbeat in children and infants called supraventricular tachycardia, or SVT.
However, Wolff-Parkinson-White syndrome may not cause any symptoms, known as being 'silent'. In these cases, it may not be detected until later in life during a routine ECG heart test.
The British Heart Foundation says most people with Wolff-Parkinson-White syndrome don't experience symptoms until their 30s or 40s.
What causes Wolff-Parkinson-White syndrome?
People with Wolff-Parkinson-White syndrome have an additional electrical connection between the upper and lower chambers of the heart (atria and ventricles).
In some people, this can short-circuit the heart's normal signals causing periods of rapid heart rates. These can last for a matter of seconds to several days in rare cases.
The charity CRY, Cardiac Risk in the Young, says this heart defect is found in around 15 people in every 10,000. Although it is present at birth, rather than developing later, it runs in families in fewer than 1% of cases.
Some people with Wolff-Parkinson-White syndrome also have structural heart defect, including problems with their heart valves known as Epstein anomaly.
Symptoms of Wolff-Parkinson-White syndrome
As well as the rapid heart rate, pulse or palpitations, a person may feel tightness in the chest, be short of breath, feel light-headed, sweat, feel dizzy or may faint. If a person with Wolff-Parkinson-White syndrome faints or collapses, this is a medical emergency and 999 should be called for an ambulance.
Diagnosing Wolff-Parkinson-White syndrome
If the symptoms a person experiences lead a doctor to suspect Wolff-Parkinson-White syndrome, they are likely to be referred to a heart specialist or cardiologist and for diagnostic tests.
An ECG test may be recommended where sensors on the skin record and trace electrical signals from the heart and any abnormal delta waves from the brain.
Because episodes of the racing heart beat may not happen during a visit to a heart clinic, a person may be asked to wear a portable version of the equipment. This can either be set to take measurements across a 24-hour period, or it can be switched on when the patient experiences the Wolff-Parkinson-White syndrome symptoms.
Treatment for Wolff-Parkinson-White syndrome
Most people with Wolff-Parkinson-White syndrome do not need treatment if the abnormal heart rate episodes are relatively short and the pulse goes back to normal on its own.
However, if the heart races non-stop for 20 minutes, the person should be taken to a hospital's A&E department. Here, a special injection can be given to stop the heart racing.
A GP and cardiologist will work together on a treatment plan.
A permanent treatment for Wolff-Parkinson-White syndrome is an operation called catheter ablation. A plastic coated wire is inserted into an artery or vein in the thigh and fed up to the heart. Once the tip of this probe is guided to the right place in the heart, radiofrequency energy is applied to the heart muscle. This breaks up the part of the heart muscle causing the short circuit and in most cases is a cure for Wolff-Parkinson-White syndrome.