Wolff-Parkinson-White (WPW) syndrome

Overview:

• This is a congenital condition caused by an abnormal myocardial connection between atrium and ventricle (via the bundle of Kent)
• During sinus rhythm, the electrical impulse can conduct quickly over this abnormal connection to depolarise part of the ventricles abnormally

The ECG:

There is a characteristic ECG pattern of WPW syndrome:

• Short PR interval
• Wide QRS complex
• Slurred upstroke (δ wave) to the QRS complex

About 50% of those with WPW pattern on the ECG have tachycardias. The tachycardias are of 2 sorts:

• Atrioventricular re-entry:
• This is a circus movement tachycardia in which a depolarisation wave travels from the atrium to the ventricle (usually through the AV node) and from the ventricle to the atrium through the abnormal pathway
• IV adenosine will terminate most of these tachycardias
• Atrial fibrillation