Overview

• Wolff-Parkinson White (WPW) syndrome is caused by a congenital accessory conducting pathway between the atria and ventricles leading to a atrioventricular re-entry tachycardia (AVRT).
• As the accessory pathway does not slow conduction AF can degenerate rapidly to VF

Possible ECG features include

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• Short P-R interval - (< 0.12 seconds) <3 boxes
• Wide QRS complex with a slurred upstroke - delta wave > 3 boxes
• Left axis deviation - if right-sided accessory pathway*
• Right axis deviation if left-sided accessory pathway*

Differentiating between type A and type B**

• Type A (left-sided pathway): dominant R wave in V1
  • This is usually always the case
• Type B (right-sided pathway): no dominant R wave in V1

Associations of WPW

• HOCM
• Mitral Valve Prolapse
• Ebstein's anomaly