B-po03-197 atrial fibrillation in wolff-parkinson-white syndrome during electrophysiology study in children: revisiting risk stratification

Wolff-Parkinson-White syndrome (WPW) has been associated with sudden cardiac death (SCD) due to rapid conduction through the accessory pathway (AP) in atrial fibrillation (AF). Adult patients (pts) are considered higher risk for SCD if the shortest preexcited RR interval (SPERRI) in AF is ≤250 milliseconds (ms) during electrophysiologic study (EPS). Patients with exclusive conduction through the atrioventricular node (AVN) in AF are presumed to have a lower risk of SCD. Additionally, the shortest preexcited paced cycle length with atrial pacing (SPPCL) has also served as a marker for risk stratification. These markers of risk in adult pts with WPW may be different in children during EPS under anesthesia. To identify pediatric WPW pts with antegrade conduction exclusively through the AVN in AF during EPS and determine the pathway characteristics in this selected patient population. This is a single center retrospective chart review. Patients with WPW ≤21 years of age that underwent EPS between 2010 to 2019 were included. All EPS were conducted under anesthesia. SPPCL was determined at baseline and on isoproterenol (ISO). Pts routinely underwent attempted induction of AF with ISO and SPERRI was measured if AF was induced. SPPCL and SPERRI measurements are reported on ISO. There were 321 pts identified. The average age was 14.3 years (IQR 11.2-16.9), 43% female. Isoproterenol was used in 286 pts (89%) and ablation was performed in 301 pts (94%). Atrial fibrillation was induced in 233/321 (73%) patients. Of those, 104 (45%) patients conducted exclusively through the AVN during AF (group 1) and the remainder (129/233, 55%) conducted through the AP (group 2). In group 1, SPPCL was 260ms (IQR 240-300) with 48/104 pts (46%) conducting through the AP at ≤250ms. In group 2, SPPCL was 240ms (IQR 220-250) with 92 pts (71%) conducting through the AP at ≤250ms (p<0.05). In group 2, SPERRI was 250ms (IQR 220-270ms) and had a minimal correlation with SPPCL (r=0.28). Almost half (46%) of WPW patients with conduction only through the AV node in AF had rapid accessory pathway conduction with atrial pacing. Therefore, conduction in AF should be used cautiously for risk stratification in children.