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

Treatment of Symptomatic Wolff-Parkinson-White Syndrome

Catheter ablation of the accessory pathway is the recommended first-line treatment for symptomatic patients with Wolff-Parkinson-White syndrome, especially those with pre-excited atrial fibrillation or a short bypass tract refractory period. 1

Acute Management of Symptomatic WPW

For hemodynamically unstable patients:

• Immediate direct-current cardioversion is recommended for patients with AF, WPW syndrome, and rapid ventricular response who are hemodynamically compromised 1

For hemodynamically stable patients with pre-excited AF:

1. IV procainamide or ibutilide to restore sinus rhythm or slow ventricular rate 1
2. Avoid medications that block the AV node as they can accelerate ventricular rate by preferential conduction through the accessory pathway:
   • Do NOT use: amiodarone, adenosine, digoxin, verapamil, diltiazem, or other non-dihydropyridine calcium channel blockers 1
   • These medications are classified as Class III: Harm (potentially dangerous) 1

Definitive Treatment

First-line therapy:

• Catheter ablation of the accessory pathway is the treatment of choice for symptomatic patients 1
  • Particularly indicated for:
    • Patients with documented pre-excited AF
    • Patients with syncope suggesting rapid heart rate
    • Patients with accessory pathways having short refractory periods (<250 ms) 1
  • Success rates are high with low complication rates 2

Pharmacological options (if ablation is not immediately available or declined):

For regular supraventricular (reciprocating) tachycardia:

• Class IC antiarrhythmic drugs (flecainide, propafenone) to prolong accessory pathway refractory periods 2, 3
• Caution with beta-blockers in WPW with pre-excitation, as they may be ineffective and potentially harmful if given intravenously 1

For pre-excited atrial fibrillation while awaiting ablation:

• Class IC antiarrhythmic drugs are preferred by most centers (80%) 3

Risk Assessment

Approximately 25% of WPW patients have accessory pathways with short anterograde refractory periods (<250 ms), which are associated with higher risk of rapid ventricular rates and ventricular fibrillation 1

Risk factors for sudden cardiac death:

• Short refractory period of accessory pathway
• Multiple accessory pathways
• History of pre-excited atrial fibrillation 1

Important Considerations

• Ablation of the accessory pathway does not always prevent AF, especially in older patients, and additional pharmacological therapy may be required 1
• The risk of developing AF over 10 years in patients with WPW syndrome is estimated at 15% 1
• Propafenone has electrophysiologic effects that can slow conduction in accessory pathways 4
• Verapamil and other calcium channel blockers are contraindicated in WPW with pre-excitation due to risk of accelerating ventricular rate 5
• Beta-blockers like propranolol have been associated with severe bradycardia in WPW patients 6

Follow-up Management

• Most patients who undergo successful ablation require no further antiarrhythmic therapy 7
• For patients who cannot undergo ablation, long-term pharmacological therapy with Class IC antiarrhythmic drugs may be necessary 2, 3

Remember that WPW syndrome with symptomatic arrhythmias, especially pre-excited AF, can be life-threatening due to the risk of degeneration to ventricular fibrillation. Prompt and appropriate treatment is essential to prevent sudden cardiac death.