6th March 2024

Wolff-Parkinson-White (WPW)

The existence of an anterograde pathway between the atria and ventricles called the bundle of Kent, allows conduction to travel faster via the accessory pathway and normal speed through the AV node and normal conductive pathway. This causes a slurred upstroke to the QRS complex known as a delta wave and shortened PR interval. When this conduction abnormality results in tachyarrhythmia, it is termed Wolff-Parkinson-White Syndrome. 

There is a small familial link with WPW, however the condition is also associated with congenital structural cardiomyopathies such as hypertrophic cardiomyopathy or Ebstein’s anomaly (apical displacement of tricuspid valve resulting in tricuspid regurgitation and atrialisation of the basal right ventricle). It is estimated that the majority of patients with WPW pattern ECG are asymptomatic.

Treatment of haemodynamically stable WPW supraventricular tachycardias includes vagal manoeuvres and medications such as Amiodarone or Procainamide. Often, pre-excited AF in the context of WPW is poorly tolerated; however, where there is haemodynamic compromise, DCCV with sedation is appropriate. Radiofrequency ablation of the accessory pathway is the treatment of choice for patients with WPW. AV nodal blocking agents such as verapamil, diltiazem, adenosine, and digoxin should be avoided in WPW as they can increase conduction via the accessory pathway leading to a ventricular arrhythmia.