Wolff-Parkinson White

Question 1

Pathophysiology?

Answer 1

There is a congenital accessory conducting pathway between the atria and ventricles leading to a atrioventricular re-entry tachycardia (AVRT).

Question 2

What is the risk with this condition?

Answer 2

As the accessory pathway does not slow conduction AF can degenerate rapidly to VF.

Question 3

Possible ECG features?

Answer 3

• short PR interval
• wide QRS complexes with a slurred upstroke - ‘delta wave’
• left axis deviation if right-sided accessory pathway*
• right axis deviation if left-sided accessory pathway*

*in the majority of cases, or in a question without qualification, Wolff-Parkinson-White syndrome is associated with left axis deviation

Differentiating between type A and type B

• type A (left-sided pathway): dominant R wave in V1
• type B (right-sided pathway): no dominant R wave in V1

Question 4

Associations of WPW?

Answer 4

• HOCM
• mitral valve prolapse
• Ebstein’s anomaly
• thyrotoxicosis
• secundum ASD

Question 5

What medical therapy can be given?

Answer 5

Sotalol, amiodarone, flecainide

Question 6

Definitive treatment?

Answer 6

Radiofrequency ablation of the accessory pathway