How should Wolff‑Parkinson‑White (WPW) syndrome be treated acutely and long‑term?

Treatment of Wolff-Parkinson-White (WPW) Syndrome

Catheter ablation of the accessory pathway is the first-line definitive treatment for all symptomatic WPW patients, with a success rate exceeding 95% and should be performed in experienced centers. 1

Acute Management Algorithm

Hemodynamically Unstable Patients

• Immediate direct-current cardioversion is mandatory for patients presenting with pre-excited atrial fibrillation and hemodynamic compromise (hypotension, altered mental status, chest pain, or pulmonary edema) to prevent progression to ventricular fibrillation. 1, 2

Hemodynamically Stable Patients with Pre-excited AF

• Intravenous procainamide is the first-line pharmacological therapy (Class I recommendation) to restore sinus rhythm in stable patients with wide QRS complexes (≥120 ms). 1, 3
• Intravenous ibutilide serves as an alternative first-line option if procainamide is unavailable. 1

Critical Medication Contraindications in Pre-excited AF

Never administer the following medications in WPW with atrial fibrillation, as they can precipitate ventricular fibrillation and sudden death: 1, 2

• Beta-blockers (metoprolol, atenolol, propranolol)
• Non-dihydropyridine calcium channel blockers (diltiazem, verapamil)
• Digoxin
• Adenosine (when QRS is wide)
• IV amiodarone during acute pre-excited AF

The mechanism of harm: these agents slow AV nodal conduction but do not affect the accessory pathway, leading to preferential rapid conduction through the bypass tract with potentially fatal ventricular rates. 2, 3

Definitive Long-Term Management

Indications for Catheter Ablation (Class I)

Ablation is mandatory for: 1

• All symptomatic patients with documented arrhythmias (palpitations, syncope, presyncope)
• Patients with documented atrial fibrillation and WPW
• Syncope due to rapid heart rate
• Short bypass tract refractory period (<240 ms)

Ablation Success Rates and Complications

• Primary success rate: 88-95%, with final success reaching 93-98.5% after repeat procedures if needed. 1
• Major complication rate: <1-2% in experienced centers, including permanent AV block (0.1%), bundle branch blocks (0.9-1.2%), and pericardial effusion (0.2%). 1
• After successful ablation, no patients developed malignant arrhythmias over 8 years of follow-up. 1

Asymptomatic Patients: Risk Stratification Approach

For truly asymptomatic patients with WPW pattern on ECG, two reasonable approaches exist: 3

Option 1: Observation without intervention (Class IIa) - acceptable for most asymptomatic adults with benign course. 3

Option 2: Electrophysiological study for risk stratification (Class IIa) - particularly recommended for: 1, 3

• Young patients (highest sudden death risk in first two decades of life)
• Competitive athletes
• Individuals with high-risk occupations (pilots, commercial drivers)
• Family history of sudden cardiac death
• Patient preference after informed discussion

High-Risk Features Requiring Immediate Ablation

Even in asymptomatic patients, ablation should be strongly considered if EP study reveals: 1, 3

• Shortest pre-excited RR interval <250 ms during atrial fibrillation (strong predictor of sudden death)
• Accessory pathway refractory period <240 ms
• Multiple accessory pathways
• Posteroseptal pathway location
• Inducible sustained AVRT

Low-Risk Features (Observation Acceptable)

• Intermittent loss of pre-excitation on ambulatory monitoring (90% positive predictive value for low risk). 3
• Abrupt loss of pre-excitation during exercise testing. 3

Special Clinical Scenarios

Patients with Symptomatic Tachycardia History

• Annual sudden death risk increases from 0.15-0.2% in general WPW patients to 2.2% in symptomatic patients. 1
• Approximately one-third of WPW patients develop atrial fibrillation, which can degenerate into ventricular fibrillation. 1, 2

Adolescents and Young Adults

• Catheter ablation is particularly preferred in this population to avoid lifelong antiarrhythmic drug therapy while maintaining excellent outcomes. 1
• The highest risk of sudden cardiac death occurs in the first two decades of life. 3

Patients Requiring Repeat Ablation

• Recurrence rates: approximately 9.7% overall, with higher rates (12.2%) in patients previously on antiarrhythmic medications. 4
• Septal pathway locations carry higher complication risk (9.1% vs 2.0% for left-sided pathways). 4

Important Clinical Pitfalls

Post-Ablation Monitoring

• Ablation of the accessory pathway does not always prevent atrial fibrillation, especially in older patients—additional therapy may be required. 1
• Continue monitoring for palpitations, syncope, dizziness, chest pain, or shortness of breath. 3

Driving Safety Considerations

• 57% of patients with supraventricular tachycardia experience episodes while driving—counsel patients accordingly before definitive treatment. 3

Pregnancy Considerations

• Women with WPW require special monitoring during pregnancy due to hemodynamic changes that may precipitate arrhythmias. 3

Associated Structural Heart Disease

• Always perform echocardiography to exclude Ebstein's anomaly, hypertrophic cardiomyopathy, or PRKAG2-related familial WPW before proceeding with treatment. 3