Wolff-Parkinson-White Syndrome (WPW) is an arrhythmia that may be characterised by abnormal electrical pathways that lead to very rapid heart rates. Patients with WPW may have an accessory electrical pathway (circuit) that allows normal electrical signals from the atrium to bypass the bridge (Atrioventricular node AV node) between the upper and lower chambers. This creates a “loop circuit” which results in rapid heart rates.
The AV nodes’ role is to limit the heart rate, by slowing down the stimulation from the atria. Therefore, the aberrant pathway allows these abnormal electrical pulses to bypass the AV node, stimulating ventricular contraction, and ensuring rapid heart rates. WPW forms a class of arrhythmias known as Paroxysmal supraventricular tachycardia (SVT).
WPW may also occur in patients who may have other structural heart abnormalities such as Epstein anomaly that can affect the tricuspid valve, which in turn, affects blood flow from the Right atrium to the Right Ventricle.1
In the below video, Cardiologist Electrophysiologist Dr Tchou, explains a heart arrhythmia, Wolff-Parkinson-White Syndrome.
WPW can occur at any age and is thought to affect approximately 1-3 per 1000 patients. The cause of WPW is unknown in the majority of cases, however, it is thought that a small percentage of these patients may have a genetic mutation. Many cases of WPW are not inherited with little to no family history. In patients who have familial WPW syndrome, the patient will have inherited the condition from an affected parent.3
Patients with WPW may present with the following signs or symptoms:
A formal diagnosis of WPW can only be made after an Electrocardiogram (ECG) that demonstrates changes on a surface ECG and indicates the potential for a “pre-excitation” syndrome. It is not uncommon for patients who have no symptoms of the condition to be diagnosed with WPW after a routine ECG that may highlight specific changes on the ECG. The presence of a “delta wave” on an ECG may indicate WPW as a clinical diagnosis.5
A Delta wave may also be described as a “slurring” of the QRS complex on ECG as highlighted with red arrows below:
More commonly, patients will present with symptoms and the condition is diagnosed after a review of their ECG. A more formal medical history might ask more detailed questions to elicit if the patient has had any previous symptoms of the condition such as:
Treatment for WPW may depend on the presence of other structural heart conditions, frequency of symptoms such as syncope (dizziness) and other familial histories, if relevant.
There are three main treatment options: