804 WOLF PARKINSON WHITE SYNDROME OR ASYMPTOMATIC VENTRICULAR PRE-EXITATION IN CHILDREN: EVALUATION OF ELECTROPHYSIOLOGICAL PROPERTIES CHANGES IN TWO DIFFERENT TIMING


 
 
 In patients with Wolf Parkinson White (WPW) syndrome or asymptomatic ventricular pre-excitation (VP), electrophysiologic study (EPS) is recommended to assess and to stratify the risk of life - threatening arrhythmias and SCD. However, little information exist on the timing of EPS study. In particular, the electrophysiological properties variations of accessory pathway (AP) in patients with asymptomatic or symptomatic VP remain to be defined. Recently, the evolution of electrophysiological data was observed in a cohort of patients by including children and adults, although a transcatheter ablation (TCA) was performed during the evaluation among the two EPS. According to our knowledge, no study exists related to the changes over time in the conductive properties of an atrioventricular accessory pathway (AP) and arrhythmic vulnerability in the pediatric - young adult population.
 
 
 
 The aim of our study was to investigate the evolution of clinical and electrophysiological datas of the manifest PV (intermittent or persistent), the arrhythmic vulnerability and any modifications in the features of AP anterograde conduction in symptomatic or asymptomatic children, examined on two separate timing, at least 2 years apart from one EPS to the next.
 
 
 
 This is a retrospective monocentric observational study performed at Bambino Gesu` Children's Hospital, Rome, Italy.
 Between January 2011 and July 2022, we enrolled forty-four children and young adults (32 male, mean age 10 years± 2,42) with manifest ventricular preexcitation underwent, as our standard management, at two electrophysiolgical studies (EPS, transesophageal and/or endocavitary), both at rest and during adrenergic stress (exercise testing or isoproterenol infusion) in two different timing (T0 and T1) within a minimal interval of 2 year. No transchateter ablation was performed between two EPS. Clinical and electrophysiological data were collected and compared.
 
 
 
 We observed a significant modification in atrioventricular accessory pathway conductive properties from T0 to T1 in basal study. In particular, at the baseline, preAVA value and 1/1 conduction VA time were respectively 306,59±43 and 292,61±61,7 and significatively decreased on occasion of second EPS evalutation (T1) (respectively to 279,51±41 with p 0,004 and 267,13±51,6, with p 0,003). Furthermore, an ARVT were induced in 14 patients in T1 respect 9 patient in T0 (p<0,03) and AF in 16 patients in T1 respect 7 patients in T0 (p 0,24). This results were not confirmed on adrenergic test during EPS evaluation.
 We also reported a clinically but not statistically relevant reduction of SPERRI time evaluated during EPS with stress test from T0 to T1 (from 251,44±47,9 to 206,9±36,7; p= 0,18).
 
 
 
 There were significant and clinically rilevant changes of electrophysiological datas in young patients with symptomatic and asymptomatic VP underwent two EPS in two different timing. Therefore, in our opinion, a systematic evaluation with repeated EPS should be considered in this population.
