Wolff-Parkinson White Syndrome

Key points

• Congenital accessory conducting pathway between atria and ventricles → atrioventricular re-entry tachycardia (AVRT) · the pathway does not slow conduction so AF can degenerate rapidly to VF
• ECG: short PR interval · wide QRS with slurred upstroke (delta wave) · left axis deviation if right-sided pathway, right axis deviation if left-sided (unqualified WPW = left axis deviation)
• Type A (left-sided pathway): dominant R wave in V1 · type B (right-sided pathway): no dominant R wave in V1 · rare type C: delta waves upright V1-V4, negative V5-V6
• Associations: HOCM · mitral valve prolapse · Ebstein's anomaly · thyrotoxicosis · secundum ASD
• Management: definitive = radiofrequency ablation · medical = sotalol, amiodarone, flecainide · in AF avoid AV nodal blockers (verapamil most contraindicated; also adenosine, beta-blockers, digoxin) — use flecainide; avoid sotalol with coexistent AF

Decision points in this pathway

• Coexistent atrial fibrillation (pre-excited AF)?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.