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. The heartbeat is regulated by electrical impulses that travel through the atria to a knot of tissue known as the atrioventricular node and then to the lower chambers of the heart. The 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 a normal delay. This extra pathway does not usually have any serious complications, however, sometimes the extra pathway may ‘bounce’ the electrical impulses back to the atria after each beat. This creates a circuit in which in which each atrial beat is followed by a ventricular beat (lower chamber), which is then followed by another atrial beat and so on. The heart rate can reach over 200 beats per minutes. The normal resting heart rate is around 70-80 beats per minute.
Between one and two per 1000 are thought to have this condition which can be managed with medications or a simple procedure to remove the extra pathway.
As one of the leading causes of a fast heart rate disorder in newborns and young children the causes are currently unknown. It remains unclear what causes the additional pathway to develop inside the heart. The condition is present at birth, but genetic factors have been ruled out, 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. Since the cause is not known, prevention is not possible.
Brief History of Discoverers:
In 1915, Frank Norman Wilson (1890 – 1952) became the first to describe the condition later called Wolff–Parkinson–White syndrome. Alfred M. Wedd (1887 – 1967) was the next to describe the condition in 1921. Cardiologists Louis Wolff (1898 – 1972), John Parkinson (1885 – 1976) and Paul Dudley White (1886 – 1973) are credited with the definitive description of the disorder in 1930.
The various symptoms of Wolff-Parkinson-White Syndrome include:
Drops in blood pressure
tightness in the chest
episodes of markedly accelerated heart rate
shortness of breath
In most cases the episodes of tachycardia are short-lived and the person can recover easily. However, as with any illness, some complication can arise including low blood pressure, loss of conciousness, heart failure, heart attack and even death.
If a person experiences any of the following symptoms Wolff-Pakinson-White syndrome is investigated using a number of different tests including:
Electrocardiogram (ECG) to measure the heart’s electrical activity
Echocardiogram to rule out associated structural heart defects
Exercise stress test to assess whether the ECG abnormality persists with vigorous exercise
Holter ECG (24hrs) to monitor the ECG and heart rate over a longer period of time
Electrophysiology Study. This 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 depend on the severity of the disease but can include anti-arrhythmic drugs an artificial pacemaker, electric cardioversion (shock) and an electrophysiology study. These treatment options aim to either slow the heart rate or prevent future attacks. One way to eliminate the extra pathway is open-heart surgery, which would be an option for chronic disease with other options already been utilised.
What’s the long-term outlook?
In some children the problem may resolve on its own as the heart matures and develops over the first few years of life. If it does persist treatment may be required.
Medications to control the heart rate don’t always work and there are unwanted side-effects to be aware of. Even the when medications are most effective, it is not desirable for patients to continue such treatment over many years.
Removing the extra pathway usually ‘cures’ the disorder; this can be done effectively in most patients after the age of around seven years old. In many cases, the extra pathway can be easily found, but if it is difficult to locate or cannot be eliminated safely than long-term medication may be necessary or surgery may be recommended.
A patient with Wolff-Parkinson-White syndrome will need ongoing monitoring, such as regular ECG’s to make sure their heart is functioning normally.
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