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What
is Wolff (Wolfe)-Parkinson-White Syndrome?
Wolff (Wolfe)-Parkinson-White (WPW) is a very rare cause of sudden
death. It results from an additional electrical connection between the
atria (upper chambers of the heart) and the ventricles (lower chambers
of the heart). This extra or accessory electrical pathway is present in
approximately 1.5 people per 1,000 people. It runs in families in less than 1%
of cases. In the majority it is completely silent and only detected on a
routine ECG. In a small proportion of patients the extra electrical
pathway allows conduction of the electrical pathway generating an
electrical circuit which produces a very rapid heart rate. Most patients
tolerate this well but some experience very troublesome palpitations,
light-headedness and blackouts. A very small minority of patients may
die suddenly from ventricular fibrillation(<0.1%
of patients).
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Symptoms
Palpitations are the main symptoms. They can occur at any time and
some patients learn to control them by holding their breath for
prolonged periods. In many instances the palpitations remain until they
are terminated by medical therapy in the accident and emergency
department.
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Signs
When the patient is experiencing palpitations the heart rate is
usually in excess of 150 beats per minute. When the patient has no
symptoms there is nothing to find on examination.
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How is Wolff (Wolfe)-Parkinson-White diagnosed?
WPW is diagnosed by performing an ECG. The ECG usually shows two
abnormalities when the patient is free of symptoms – a short PR
interval and a delta wave. It is often an incidental finding during a
routine ECG check as part of a medical insurance or detected by a
cardiologist when a patient is referred with palpitations.
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Treatment
The ideal treatment in patients with symptoms is to destroy the extra
electrical pathway, a procedure termed radio frequency
catheter ablation. This is
done by passing a wire into the heart, often via the large artery (femoral
artery) in the leg. The abnormal pathway is located by electrical
stimulation and destroyed by passing a high current through it. This
takes approximately 2-3 hours and requires one night in hospital. For
patients above 25 years without any symptoms there is no need for
further tests. Younger patients (under 25 years) are most at risk of
sudden death and require further tests to assess their risk of
developing life threatening electrical disturbances. This is best done
by performing an exercise test under the supervision of a cardiologist.
The abrupt disappearance of the delta wave on the ECG as the heart rate
increases is a good sign, obviating any further
investigation. However, if this does not happen then further electrophysical testing is recommended before one can be reassured.
The pathways can also
disappear or degenerate as patients get older.
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With special thanks for the Medical Information
that has been
provided by our team
of experts
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