Variability of Accessory Pathway Refractory Periods: What Should be the Criteria for Ablation in Asymptomatic WPW

What then are the criteria to select patients of Asymptomatic WPW who may be predisposed to SCD? The markers identified for SCD include: 1. Anterograde effective refractory period of accessory pathway (APERP) 240250ms; (on isoproternol APERP <200ms?) 2. Shortest Preexcited RR interval (SPERRI) less than 250ms during or induced AF. 3. Multiple accessory pathways 4. Ebsteins anomaly 5. Familial WPW syndrome. The Non invasive parameters of a presumed long refractory period of bypass tract (>250ms) include: 1. Intermittent pre-excitation. 2. Disappearance of pre-excitation during exercise and 3. Disappearance of pre-excitation with procainamide. The predictive value of the non invasive parameters is low and when combined with the low risk of RF ablation, most electrophysiologists rely on invasive testing to risk stratify asymptomatic patients. In a European survey 44% of EP centers perform invasive approach as the first line approach [3] in asymptomatic WPW.