Wolff-Parkinson-White syndrome (WPW) results from an additional electrical connection between the upper chambers of the heart (atria) and the lower chambers of the heart (ventricles). This extra or accessory electrical pathway is present in approximately 1 in every 300-500 people. WPW is rarely inherited through the DNA. 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 individuals (1%) the extra electrical pathway allows conduction of the electrical pulse at high speed generating an electrical circuit, which produces a rapid heart rate. Most patients tolerate this well but some experience very troublesome palpitations, associated chest pain, light-headedness and blackouts.
CRY Consultant Cardiologist Professor Sanjay Sharma talks about Wolff-Parkinson-White syndrome (WPW) below. Please note, at 3:03 Professor Sharma meant to say that deaths due to WPW are rare in people above the age of 21, not below.
What are the symptoms?
Palpitations are the main symptom. 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.
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.
How is it diagnosed?
WPW is diagnosed by performing an ECG. It is often an incidental finding during a routine ECG check as part of medical insurance, cardiovascular screening or detected by a cardiologist when a patient is referred with palpitations. Other investigations include an ultrasound scan of the heart to exclude structural abnormalities, an exercise treadmill test and a 24-hour Holter monitor (tape) to assess the presence of fast and irregular heart rhythm.
In competitive athletes and patients with troublesome symptoms or documented arrhythmias, further invasive tests would be recommended to assess the electrical properties of the accessory pathway and therefore the risk of significant arrhythmias (electrophysiological studies).
Watch CRY’s myheart cardiologist, Dr Michael Papadakis, talk about the next stage after being diagnosed with WPW below.
Treatment and advice
The ideal treatment in patients with symptoms is to destroy the extra electrical pathway, a procedure termed radio frequency ablation (RF ablation). This is done by passing a wire into the heart 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.
In some cases, with no evidence of dangerous arrhythmias, drug therapy may be preferred by the patient who is not keen to undergo an invasive procedure or when detection and/or ablation of the accessory pathway is technically difficult.
The pathways can also degenerate or even disappear as patients get older.