What is the initial approach to managing Wolff-Parkinson-White (WPW) syndrome in a child?

Initial Management of Wolff-Parkinson-White Syndrome in Children

The initial approach to managing Wolff-Parkinson-White syndrome in a child should include risk stratification followed by referral for catheter ablation of the accessory pathway for symptomatic patients, as this is the therapy of choice to prevent potentially life-threatening arrhythmias. 1, 2

Diagnosis and Initial Assessment

• Diagnosis is based on ECG findings including PR interval <100 ms, QRS complex duration <80 ms, lack of Q wave in V6, and left axis deviation 1
• Complete 2-dimensional echocardiography is recommended for all children with WPW to rule out associated congenital heart defects, which have a prevalence as high as 45% in infants with right-sided accessory pathways 1
• Risk stratification should be performed to identify children at higher risk for sudden cardiac death, which occurs at a rate of approximately 0.5% in pediatric WPW patients 1

Risk Stratification

High-risk features that warrant more aggressive management include:

• Shortest pre-excited R-R interval less than 250 ms during spontaneous or induced atrial fibrillation 1, 2
• History of symptomatic tachycardia or syncope 2
• Multiple accessory pathways 1
• Associated Ebstein's anomaly or other structural heart disease 1

Acute Management of Tachyarrhythmias

For children presenting with tachyarrhythmias:

• Hemodynamically unstable patients: Immediate electrical cardioversion is the first-line therapy to prevent ventricular fibrillation 2
• Hemodynamically stable patients with narrow QRS complex: IV adenosine may be used as it indicates anterograde conduction through the AV node 2
• Hemodynamically stable patients with wide QRS complex (≥120 ms): IV procainamide or ibutilide are preferred to restore sinus rhythm 2

Critical Medication Considerations

• AVOID AV nodal blocking agents including digoxin, diltiazem, verapamil, and beta-blockers in patients with pre-excited atrial fibrillation as they can increase the ventricular response rate and potentially precipitate ventricular fibrillation 1, 2
• Two documented cases of sudden death in infants with WPW syndrome were associated with digoxin treatment 1
• Adenosine should be used with caution as it may produce atrial fibrillation with a rapid ventricular rate in pre-excited tachycardias 1

Definitive Management

• Catheter ablation of the accessory pathway is the therapy of choice for symptomatic children with WPW syndrome 1, 2
• For asymptomatic children with incidental WPW pattern on ECG, risk stratification through transesophageal programmed stimulation may be useful to determine management approach 1
• If medication is needed before definitive treatment:
  • Propafenone has shown efficacy in 69% of children with AVRT, though side effects occurred in 25% 1
  • Beta-blocker therapy may be used if the accessory pathway has been demonstrated to be incapable of rapid anterograde conduction 1

Special Considerations in Children

• The prevalence of WPW syndrome in the pediatric population is estimated at 0.15-0.3% 1
• Children with WPW have an increased risk of developing atrial fibrillation and a small but significant risk of sudden cardiac death 3
• Intermittent pre-excitation (characterized by abrupt loss of the delta wave) is not uncommon in newborns and infants and suggests a lower risk of sudden death 1

Follow-up Recommendations

• Regular cardiology follow-up for children managed medically to assess for symptom recurrence and development of new arrhythmias 4
• Post-ablation follow-up should include ECG to confirm elimination of pre-excitation 5
• Long-term surveillance may still be needed as ablation will not necessarily prevent the occurrence of atrial fibrillation, especially in older patients 1

By following this structured approach to managing WPW syndrome in children, clinicians can effectively reduce the risk of sudden cardiac death and improve quality of life by preventing recurrent symptomatic arrhythmias.