What is the recommended acute and long‑term management for a patient with Wolff‑Parkinson‑White (WPW) syndrome presenting with tachyarrhythmia?

Wolff-Parkinson-White Syndrome Treatment Plan

Acute Management Algorithm

For hemodynamically unstable patients with WPW presenting with tachyarrhythmia, perform immediate direct-current cardioversion to prevent ventricular fibrillation. 1, 2, 3

Hemodynamically Unstable Patients

• Immediate electrical cardioversion is the Class I recommendation for any patient showing signs of hemodynamic compromise (hypotension, altered mental status, chest pain, or pulmonary edema) 1, 2, 3
• Have resuscitation equipment immediately available, as pre-excited atrial fibrillation carries high risk for degenerating into ventricular fibrillation 3

Hemodynamically Stable Patients with Pre-excited Atrial Fibrillation (Wide QRS ≥120 ms)

Administer intravenous procainamide or ibutilide as first-line pharmacological therapy (Class I recommendation). 1, 2, 3

• IV procainamide is the preferred agent, as it blocks conduction through the accessory pathway and restores sinus rhythm 1, 2, 4
• IV ibutilide is an equally effective alternative with Class I recommendation 1, 2
• IV flecainide represents a Class IIa alternative option 2, 5
• Class IIb alternatives include IV quinidine, disopyramide, or amiodarone if first-line agents are unavailable 2, 3

Critical Medication Contraindications

Never administer AV nodal blocking agents in WPW patients with pre-excited atrial fibrillation, as they can precipitate ventricular fibrillation and sudden cardiac death. 1, 2, 3

Absolutely contraindicated medications include:

• Beta-blockers (including metoprolol, esmolol) - accelerate conduction through the accessory pathway 1, 2, 3
• Non-dihydropyridine calcium channel blockers (verapamil, diltiazem) - same mechanism of harm 1, 2, 3
• Digoxin - enhances accessory pathway conduction 1, 2, 3
• Adenosine when QRS is wide (≥120 ms) - can trigger atrial fibrillation with rapid ventricular response 1, 3

The mechanism of harm: these agents slow AV nodal conduction but leave the accessory pathway unaffected, resulting in preferential conduction through the bypass tract with potentially fatal ventricular rates exceeding 300 bpm 1, 4

Long-Term Definitive Management

Catheter ablation of the accessory pathway is the first-line definitive treatment for all symptomatic WPW patients and should be performed in experienced centers. 1, 2, 6

Indications for Catheter Ablation (Class I)

• Any patient with documented symptomatic arrhythmias 1
• Patients with atrial fibrillation and WPW 1, 2
• Syncope due to rapid heart rate 1
• Short bypass tract refractory period (<250 ms during atrial fibrillation) 1, 3
• First episode of pre-excited atrial fibrillation (80% of centers refer immediately for ablation within weeks) 7
• Second episode of orthodromic atrioventricular reentry tachycardia (79-91% of centers refer for immediate ablation) 7

Ablation Success Rates and Complications

• Primary success rate: 88-95%, with final success reaching 93-98.5% after repeat procedures 1
• Success rate exceeds 95% in experienced centers 1, 2
• Permanent AV block risk: <1-2% in experienced centers 1
• Other complications include right bundle branch block (0.9%), left bundle branch block (0.3%), third-degree AV block (0.1%), pericardial effusion (0.2%), and femoral complications (1%) 1

Post-Ablation Monitoring

• Ablation eliminates the accessory pathway but does not always prevent atrial fibrillation recurrence, particularly in older patients 1, 2
• Over 8 years of follow-up after successful ablation, no patients developed malignant atrial fibrillation or ventricular fibrillation 1

Risk Stratification for Sudden Cardiac Death

High-risk features requiring urgent ablation consideration:

• Short RR intervals (<250 ms) between pre-excited beats during atrial fibrillation - strongest predictor of sudden cardiac death risk 1, 3
• History of symptomatic tachycardia (increases annual SCD risk from 0.15-0.2% to 2.2%) 1
• Multiple accessory pathways 1
• Posteroseptally located pathways 1
• Documented pre-excited atrial fibrillation 1, 2

Special Considerations

Asymptomatic WPW Pattern

• Invasive electrophysiological study with possible ablation may be offered to well-informed asymptomatic individuals, particularly those in high-risk professions (pilots, athletes, commercial drivers) 6, 7
• Younger asymptomatic patients are more likely to receive risk stratification or ablation compared to older patients, despite older patients having higher atrial fibrillation risk 7
• Inducibility of arrhythmias during electrophysiology study predicts future symptomatic arrhythmias 6

Pediatric Patients

• Catheter ablation is preferred in adolescents to avoid lifelong antiarrhythmic therapy 1
• Most centers perform 0-9 pediatric ablations per year in children under 12 years old 7

Common Pitfalls

• Do not use adenosine if QRS is wide during tachycardia - only safe when QRS <120 ms, indicating anterograde conduction through AV node 3
• Approximately one-third of WPW patients develop atrial fibrillation, which can degenerate into ventricular fibrillation 1
• Discontinuation of scheduled ablation due to close proximity to AV node is rare in experienced centers 7
• 50.9% of centers use electrical cardioversion for pre-excited atrial fibrillation, while 80% choose Class IC antiarrhythmics as bridge therapy to ablation 7