Wolff-Parkinson-White syndrome
Wolff-Parkinson-White syndrome
About Wolff-Parkinson-White syndrome
Wolff-Parkinson-White syndrome is characterised by attacks of rapid
heart
rate (tachycardia), which is shown in an
electrocardiogram (ECG)
. In some people the ECG abnormality may be present without any symptoms such as tachycardia.
The heartbeat is regulated by electrical impulses that travel through the atria (upper chambers of the heart) to a knot of tissue known as the atrioventricular node, and then to the ventricles (lower chambers of the heart). Usually electrical impulses pause at the atrioventricular node before prompting the ventricles to contract.
In Wolff-Parkinson-White syndrome, an extra pathway conducts the electrical impulses to the ventricles without the normal delay. This extra pathway does not usually have serious consequences. However sometimes the extra (“accessory”) pathway may “bounce” the electrical impulses back to the atria after each beat. This creates a circuit in which each atrial (upper chamber) beat is followed by a ventricular (lower chamber) beat, which is then followed by another atrial beat and so on. The heart rate can reach over 200 beats per minute, when the normal resting heart rate is around 70 to 80 beats per minute.
Between 1-2 people per 1000 are thought to have Wolff-Parkinson-White syndrome. The condition can be managed with medications and a procedure to get rid of the extra pathway, which usually does not require surgery.
Symptoms of Wolff-Parkinson-White syndrome
The symptoms of Wolff-Parkinson-White syndrome include:
episodes of markedly accelerated heart rate (usually faster than 200 beats per minute)
heart palpitations
tightness in the chest
shortness of breath
drop in
blood pressure
light-headedness
dizziness
fainting spells.
Complications of Wolff-Parkinson-White syndrome
In most cases the episodes of tachycardia are short-lived and the person recovers quickly. However some of the complications of Wolff-Parkinson-White syndrome can include:
low blood pressure
loss of consciousness
heart failure
death.
The cause is unknown
Wolff-Parkinson-White syndrome is one of the leading causes of fast heart rate disorder in newborns and young children. It is not clear what causes the additional pathway to develop inside the heart.
The condition is present at birth, but genetic factors usually do not play a major role. However some families may have more than one affected individual and there does appear to be a weak hereditary tendency, with an increased incidence in the children of affected individuals (4-5 per 1000). Since the cause is unknown, prevention is not possible.
Diagnosis methods
Wolff-Parkinson-White syndrome is investigated using a number of tests, including:
physical examination
medical history
electrocardiogram (ECG) to measure the heart’s electrical activity
echocardiogram to rule out associated structural heart defects
exercise testing to assess whether the ECG abnormality persists with exercise
holter (24 hour) ECG to monitor the heart rate over a longer period
electrophysiology study, which measures the heart’s electrical activity by threading a number of catheters through the blood vessels, from the groin to the heart, to map the heart’s electrical activity.
Treatment options
for Wolff-Parkinson-White syndrome
The treatment options for Wolff-Parkinson-White syndrome depend on the severity, but can include:
Vagal manoeuvres
– use of various ’tricks’ that may cause a nerve reflex to slow the heart rate. These tricks could include blowing hard against resistance (such as with mouth and nose closed) or a facial ice pack. A cardiologist will provide advice.
Anti-arrhythmic drugs
– to slow the heart rate or to prevent attacks.
Electric cardioversion (shock)
– to stop a tachycardia attack.
An electrophysiology study
– to locate the site of the extra pathway and eliminate it, using a short treatment with radio frequency energy, applied through a catheter.
An artificial pacemaker
– to help regulate the heart rate.
Open-heart surgery
– to eliminate the extra pathway.
Long term outlook
In some children the problem may resolve on its own, usually within the first few years of life. If it persists then most individuals will require treatment.
Medications
to control the heart rate don’t always work, or may cause unwanted side effects.
Removing the extra pathway, via catheterisation, usually cures the disorder. This can be done effectively in most patients after the age of about 7 years. In many cases, the extra pathway is easily found, but sometimes it’s difficult to locate. If it cannot be found or eliminated safely then long-term medication may be necessary or surgery might be recommended.
A person with Wolff-Parkinson-White syndrome will need ongoing monitoring, such as regular ECGs, to make sure their heart is functioning normally.
Where to get help
Your
GP (doctor)
HeartKids
Victoria
External Link
Tel.
1800 432 785
Genetic Alliance
Australia
External Link