WPW and preexcitation syndromes.

Wolff-Parkinson-White syndrome is a disorder characterized by presence of an accessory pathway which predisposes patients to tachyarrhythmias and sudden death. Among patients with WPW syndrome, atrioventricular reentrant tachycardia (AVRT) is the most common arrhythmia, accounting for 95% of re-entrant tachycardias. It has been estimated that one-third of patients with WPW syndrome have atrial fibrillation (AF). AF is a potentially life-threatening arrhythmia. If an accessory pathway has a short anterograde refractory period, then rapid repetitive conduction to the ventricles during AF can result in a rapid ventricular response with subsequent degeneration to ventricular fibrillation (VF). The accessory pathway may be located anywhere along the atrioventricular valve Most of the patients are young and do not have structural heart disease hence it is important to risk stratify these patients so as to prevent the sudden death. Management of asymptomatic patients with WPW syndrome has always remained controversial Catheter ablation of accessory pathways has become an established mode of therapy for symptomatic patients and asymptomatic patients employed in high-risk professions.