A.fib and VT in WPW

 Q: Which arrhythmia is more common in Wolff-Parkinson-White (WPW) syndrome? (select one) 

A) Atrial fibrillation (AF)

B) Ventricular tachycardia (VT)

Answer: A

About one-third of patients with WPWmay have AF. Although AF can originate independently from atria or pulmonary veins, the hallmark pathology is via an accessory pathway due to retrograde conduction. If AF occurs via an accessory pathway, EKG shows the characteristic change of QRS morphology from beat to beat. AF in WPW at the rapid ventricular rate (RVR) of 180-200 beats/minute appears as "pseudo-regularized" and above 300 beats/minute degenerate into V.fib. 

Primary VT is very uncommon in WPW.

#cardiology

References:

1. Josephson ME. Preexcitation syndromes. In: Clinical Cardiac Electrophysiology, 4th, Lippincot Williams & Wilkins, Philadelphia 2008. p.339.

2. Campbell RW, Smith RA, Gallagher JJ, et al. Atrial fibrillation in the preexcitation syndrome. Am J Cardiol 1977; 40:514. 

3. Sharma AD, Klein GJ, Guiraudon GM, Milstein S. Atrial fibrillation in patients with Wolff-Parkinson-White syndrome: incidence after surgical ablation of the accessory pathway. Circulation 1985; 72:161.