What is the appropriate acute and long‑term treatment for Wolff‑Parkinson‑White syndrome?

Treatment for Wolff-Parkinson-White Syndrome

Radiofrequency catheter ablation is the first-line definitive treatment for symptomatic WPW syndrome, with success rates of 93-98.5%, and should be performed in experienced centers for any patient who has experienced symptomatic arrhythmias. 1

Acute Management Algorithm

Hemodynamically Unstable Patients

• Immediate direct-current cardioversion is mandatory when tachyarrhythmias cause hemodynamic compromise, hypotension, or ventricular fibrillation 1, 2
• This is a Class I intervention to prevent ventricular fibrillation and should be performed without delay 2

Hemodynamically Stable Patients with Pre-excited Atrial Fibrillation

• Ibutilide, procainamide, or flecainide are the preferred first-line agents for stable antidromic AVRT or atrial fibrillation with pre-excitation (wide QRS ≥120 ms) 1, 2
• These agents work by slowing conduction through the accessory pathway rather than the AV node 1
• Intravenous procainamide or ibutilide carry Class I recommendations for restoring sinus rhythm 2

Critical Contraindications in Acute Pre-excited Tachycardia

Never administer the following medications in WPW patients with tachycardia and ventricular pre-excitation, as they can precipitate ventricular fibrillation: 1, 2

• Intravenous beta-blockers (including metoprolol) 1, 2
• Digitalis/digoxin 1, 2
• Adenosine (when QRS is wide) 1, 2
• Nondihydropyridine calcium channel antagonists (verapamil, diltiazem) 1, 2
• Lidocaine 1

These agents slow AV nodal conduction but do not affect the accessory pathway, which can facilitate rapid antegrade conduction along the accessory pathway and trigger ventricular fibrillation 1, 2

Definitive Treatment: Catheter Ablation

Indications for Ablation

Catheter ablation should be performed for: 1, 2

• All symptomatic patients with documented arrhythmias 2
• Patients with syncope due to rapid heart rate 2
• Patients with short bypass tract refractory period (<250 ms between pre-excited beats during AF) 2
• Patients with documented atrial fibrillation and WPW 2

Success Rates and Complications

• Primary success rate: 88-95%, with final success reaching 93-98.5% after repeat procedures if needed 1, 2
• Permanent AV block occurs in <1-2% of cases in experienced centers 2
• Other complications include right bundle-branch block (0.9%), left bundle-branch block (0.3%), pericardial effusion (0.2%), and femoral hematomas (1%) 2
• After successful ablation, no patients developed malignant atrial fibrillation or ventricular fibrillation over 8 years of follow-up 2

Post-Ablation Considerations

• Previous medication restrictions no longer apply after successful ablation, as the anatomic substrate has been eliminated 1
• Verify ablation success through documentation showing absence of pre-excitation on ECG and no inducible arrhythmias during post-procedure testing 3
• Approximately 5-8% of patients may experience recurrence of accessory pathway conduction after ablation, requiring repeat evaluation 3
• Ablation does not always prevent atrial fibrillation, especially in older patients, so continued monitoring may be necessary 2

Chronic Oral Maintenance Therapy (Bridge to Ablation)

For Patients Without Active Pre-excited Arrhythmias

• Beta-blockers and calcium channel blockers are reasonable for oral chronic maintenance therapy 1
• These are only appropriate when there is no active pre-excitation during arrhythmias 1

For Prevention of Recurrent Paroxysmal Atrial Fibrillation

• When using antiarrhythmic agents like propafenone or flecainide, AV nodal blocking drugs should be routinely coadministered 1
• Class IA or IC antiarrhythmic agents can be used to slow accessory pathway conduction 4

Risk Stratification in Adolescents and Young Adults

The annual risk of sudden cardiac death is 0.15-0.2% in general WPW patients but increases to 2.2% in symptomatic patients. 2

High-Risk Features Include:

• History of symptomatic tachycardia 2
• Short RR intervals (<250 ms) between pre-excited beats during atrial fibrillation 2
• Multiple accessory pathways 2
• Posteroseptally located pathways 2
• Documented atrial fibrillation (occurs in up to one-third of WPW patients) 2, 5

Common Pitfalls to Avoid

• The most dangerous error is administering AV nodal blocking agents during acute pre-excited tachycardia, which can precipitate ventricular fibrillation and sudden cardiac death 1, 2
• Do not confuse pre-excited atrial fibrillation with ventricular tachycardia—pre-excited AF is irregular with rates >200 bpm, while VT is typically regular 6
• Recognize that approximately one-third of WPW patients develop atrial fibrillation, which can degenerate into ventricular fibrillation if the accessory pathway has a short refractory period 5, 7
• After ablation, continue monitoring as the procedure eliminates the accessory pathway risk but does not guarantee prevention of future atrial fibrillation 2