What is the first line treatment for Wolff-Parkinson-White (WPW) syndrome?

First-Line Treatment for Wolff-Parkinson-White Syndrome

Catheter ablation of the accessory pathway is the first-line treatment for symptomatic patients with Wolff-Parkinson-White syndrome. 1, 2

Acute Management Based on Presentation

For Hemodynamically Unstable Patients:

• Immediate direct-current cardioversion is recommended for patients with WPW who develop atrial fibrillation with rapid ventricular response causing hemodynamic instability 1, 2
• Start with 100 J and increase in a stepwise fashion if needed 2

For Hemodynamically Stable Patients:

1. For orthodromic AVRT (narrow complex tachycardia):

   • Vagal maneuvers (success rate up to 27.7%) 2
   • If unsuccessful, IV procainamide or ibutilide to restore sinus rhythm 1
   • Adenosine can be effective in 90-95% of cases but should be used with caution as it may precipitate atrial fibrillation 2

2. For pre-excited atrial fibrillation (wide complex tachycardia):

   • IV procainamide or ibutilide to restore sinus rhythm 1, 2
   • AVOID AV nodal blocking agents (digoxin, calcium channel blockers, beta-blockers, adenosine) as they can accelerate ventricular rate by preferential conduction through the accessory pathway 1, 2

Definitive Management

Catheter Ablation:

• Success rates >95% with low complication rates 2, 3
• Class I recommendation for symptomatic patients with WPW syndrome 1
• Particularly indicated for:
  • Patients with pre-excited atrial fibrillation
  • Patients with syncope due to rapid heart rate
  • Patients with accessory pathways with short refractory periods (<250 ms) 1, 2

Antiarrhythmic Medications (if ablation is not immediately available):

• Class Ia (quinidine, procainamide) or Ic (flecainide, propafenone) antiarrhythmic agents 2, 4, 5
• These medications prolong the refractory period of the accessory pathway and prevent rapid conduction 4, 5
• Amiodarone may be considered as an alternative 2

Risk Stratification for Asymptomatic Patients

High-risk features warranting consideration of prophylactic ablation:

• Shortest pre-excited R-R interval <250 ms during atrial fibrillation
• Multiple accessory pathways
• Septal pathway location (higher complication risk, 9.1% vs 2.0% for left-sided pathways) 2, 3
• Professional considerations (pilots, athletes, heavy machinery operators) 1, 6

Follow-up After Ablation

• ECG assessment at 3 months post-procedure and annually for the first few years 2
• Overall recurrence rate is approximately 9.7% 3
• Prior use of antiarrhythmic medications is associated with higher recurrence rates (12.2% vs 7.6%) 3

Important Caveats and Pitfalls

1. Never administer AV nodal blocking agents (digoxin, diltiazem, verapamil, adenosine) in patients with WPW and atrial fibrillation, as these can accelerate conduction through the accessory pathway and potentially cause ventricular fibrillation 1, 2

2. Catheter ablation should not be reserved as a last resort but considered first-line therapy for symptomatic WPW patients 1, 2

3. Septal accessory pathways carry higher procedural risks due to proximity to the AV node 2, 3

4. Ablation may not prevent future atrial fibrillation, especially in older patients, and additional pharmacological therapy may be required 2