SVT | Wolff Parkinson White

Key points:

  • The Wolff-Parkinson-White syndrome (WPW) is a condition in which patients are born with an extra electrical connection within the heart which causes palpitations
  • The presence of this abnormal pathway can often be detected on a routine ECG
  • Rarely dangerous disturbances of heart rhythm occur, and very rarely patients with this condition may die suddenly
  • A cauterising procedure (ablation) is highly effective in curing most patients with this condition


Normal heart activity and heart activity in patients with WPW.

Waves of electricity flow across and down the heart in an ordered fashion, and are responsible for beating of the heart. The top chambers of the heart, the atria, serve as priming chambers for the main pumping chambers, the ventricles. Patients with WPW are born with an additional electrical connection (accessory pathway) between the atria and ventricles. This connection, which in fact is a very small muscle fibre, may lie on either the left or right side of the heart. Sometimes it lies close to the normal electrical pathways of the heart.

Figure 1 shows an ECG from a patient with Wolff Parkinson White (WPW).

Figure 2 shows a typical electrical circuit that cause palpitations in patients with Wolff Parkinson White (WPW).

figure 3

Figure 1

Figure 2


The commonest symptom is palpitations (an awareness of a rapid heartbeat). Sometimes patients experience shortness of breath, dizziness or mild chest discomfort during attacks. In a very small number of patients very fast palpitations may occur, resulting in severe dizziness or even a blackout. Sudden death is a tragic but well-recognised complication of this condition that occurs very rarely.


It is important to perform an ECG in all patients with palpitations, and in patients with WPW, the ECG usually gives the diagnosis. Occasionally the diagnosis is not certain, and further investigations are required. 

Although 24 hour or longer periods of monitoring may be carried out, this is generally not required in patients with WPW. Most arrhythmia doctors agree that ablation is the best treatment, even if the heart rhythm at the time of symptoms has not been documented.

It is often desirable to perform an ultrasound scan of the heart (echocardiogram) to confirm that there are no abnormalities of the pumping chambers or heart valves.

The ultimate diagnostic test, if the ECG findings are not clear-cut, is to perform an electrophysiologic study (EPS) by inserting thin wires into the heart through a vein at the top of the leg. This is usually performed immediately prior to undertaking a radiofrequency ablation.


As very rarely dangerous heart rhythms may occur in patients with WPW, most electrophysiologists recommend treatment. Whilst drugs may often control palpitations, ablation provides a cure for the majority of patients and is the generally recommended treatment. Please see the section on catheter ablation see catheter ablation section.




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