**Core Concept:** Wolff-Parkinson-White (WPW) syndrome is a congenital pre-excitation syndrome characterized by the presence of an accessory pathway between the atria and ventricles. Atrial fibrillation is a common arrhythmia in these patients.

**Why the Correct Answer is Right:** In patients with Wolff-Parkinson-White syndrome, the presence of the accessory pathway can lead to the development of atrial fibrillation due to re-entry circuits. Atrial fibrillation management is focused on rate control and rhythm control. The drug of choice for rhythm control is class Ic antiarrhythmic agents like flecainide and propafenone, which target the fast sodium channels in the accessory pathway and prevent re-entry.

**Why Each Wrong Option is Incorrect:** A) Beta-blockers are used for rate control, not rhythm control. B) Calcium channel blockers like verapamil are rate control agents, not rhythm control agents. C) Disopyramide is a class III antiarrhythmic drug, which is not the most effective option for rhythm control in WPW syndrome.

**Clinical Pearl/High-Yield Fact:** In patients with WPW syndrome and atrial fibrillation, rhythm control is essential to prevent complications like stroke, heart failure, and embolism. Flecainide or propafenone should be the drug of choice, while beta-blockers, calcium channel blockers, and class III antiarrhythmics are not as effective for rhythm control in this population.

**Correct Answer:** D) Flecainide or Propafenone.