Loss of Ventricular Pre-excitation During Non-invasive Testing Does Not Exclude High-Risk Accessory Pathways: A Multicenter Study of WPW in Children

Abstract Background Abrupt loss of ventricular pre-excitation on non-invasive evaluation, or non-persistent pre-excitation, in Wolff-Parkinson-White syndrome (WPW) is thought to indicate a low risk of life-threatening events. Objective To compare accessory pathway (AP) characteristics and occurrences of sudden cardiac arrest (SCA) and rapidly conducted pre-excited atrial fibrillation (RC-AF) in patients with non-persistent and persistent pre-excitation. Methods Patients ≤21 years with WPW and invasive electrophysiology study (EPS) data, SCA, or RC-AF were identified from multicenter databases. Non-persistent pre-excitation was defined as absence/sudden loss of pre-excitation on ECG, Holter, or exercise test. RC-AF was defined as clinical pre-excited atrial fibrillation with shortest pre-excited R-R interval (SPERRI) ≤250ms. AP effective refractory period (APERP), SPERRI at EPS (EPS-SPERRI), and shortest pre-excited paced cycle length (SPPCL) were collected. High-risk APs were defined as APERP, SPERRI, or SPPCL ≤250ms. Results Of 1589 patients, 244 (15%) had non-persistent pre-excitation and 1345 (85%) had persistent pre-excitation. There were no differences in sex (58 vs 60% male, p=0.49) or age (13.3±3.6 vs 13.1±3.9 years, p=0.43) between groups. Though APERP (344±76 vs 312±61ms, p Conclusion Non-persistent pre-excitation was associated with fewer high-risk APs, though it did not exclude risk of SCA or RC-AF in children with WPW.