What is the initial management and treatment for Wolf Parkinson White (WPW) syndrome?

Management of Wolff-Parkinson-White (WPW) Syndrome

Catheter ablation of the accessory pathway is the recommended first-line treatment for symptomatic patients with WPW syndrome, particularly those with syncope due to rapid heart rate or those with a short bypass tract refractory period. 1

Initial Assessment and Management

Acute Management of WPW with Atrial Fibrillation

When a patient with WPW presents with atrial fibrillation (AF), management depends on hemodynamic stability:

1. Hemodynamically unstable patients:

   • Immediate direct-current cardioversion to prevent ventricular fibrillation 1
   • This is critical as patients with WPW who develop AF with rapid ventricular response are at high risk of deteriorating to ventricular fibrillation

2. Hemodynamically stable patients with AF and wide QRS complex:

   • Intravenous procainamide or ibutilide to restore sinus rhythm 1
   • IV flecainide is reasonable when very rapid ventricular rates occur 1
   • Other options include IV quinidine, disopyramide, or amiodarone 1

Critical Medication Contraindications

• AVOID these medications in WPW patients with pre-excited AF 1:
  • Beta-blockers
  • Digitalis glycosides
  • Non-dihydropyridine calcium channel antagonists (diltiazem, verapamil)
  • Adenosine
  • Amiodarone (IV)

These medications block the AV node, which can encourage preferential conduction over the accessory pathway, potentially accelerating ventricular rate and precipitating ventricular fibrillation 1.

Definitive Management

Catheter Ablation

• First-line therapy for symptomatic WPW patients 1
• Particularly indicated for:
  • Patients with documented AF or syncope
  • Those with short bypass tract refractory periods (<250 ms)
  • Patients with multiple accessory pathways (higher risk of ventricular fibrillation) 1

Catheter ablation has become the treatment of choice due to:

• High success rates (90-95%)
• Low complication rates
• Cost-effectiveness compared to long-term medical therapy 2, 3

Pharmacological Management

For patients awaiting ablation or when ablation is not feasible:

• For prevention of recurrent tachyarrhythmias:

  • Class IA (quinidine, procainamide) or IC (flecainide, propafenone) antiarrhythmic agents that prolong AP refractory periods 2, 4
  • Amiodarone may be effective for long-term management in selected cases

• For acute termination of regular supraventricular tachycardia (narrow QRS):

  • Adenosine can be used only when the QRS is narrow (<120 ms), indicating antegrade conduction through the AV node 1

Risk Assessment

Patients at highest risk of sudden cardiac death include:

• Those with short antegrade bypass tract refractory periods (<250 ms)
• Patients with short R-R intervals during pre-excited AF
• Those with multiple accessory pathways 1

Follow-up Considerations

• Ablation of the bypass tract may not prevent AF, especially in older patients
• Additional pharmacological therapy may be required even after successful ablation 1
• Regular follow-up with ECG monitoring is recommended to ensure absence of pre-excitation

Special Populations

For pregnant patients with WPW who develop AF:

• Direct-current cardioversion is recommended if hemodynamically unstable 1
• Pharmacological options are limited due to fetal considerations

In pediatric patients with WPW:

• Careful risk assessment is essential
• Catheter ablation is generally deferred until older age unless high-risk features or significant symptoms are present