Ventricular pre-excitation in young patients: long term follow-up and natural history in a contemporary cohort
Authors: Seganti A , Sanzo A , Codazzi A C , Raso I , Bongiorno A , Fino R , Munafo' A R , Apicella A , Loiacono F , Frassica R , Santacesaria S , Petracci B , Mannarino S , Rordorf R 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
Ventricular preexcitation (VPE) due to atrio-ventricular accessory pathways (AP) has been associated to a higher incidence of sudden cardiac death (1,2). The incidence of major arrhythmic events (MAE) may be higher in children (1,3), but most of the past studies recruited a high proportion of patients with congenital heart disease (CHD), treated with outdated pharmacological therapy (1). Transcatheter ablation (TCA) of the AP is a safe and effective therapy and it is nowadays the standard of care (1,2). However, it may be less effective and more dangerous in smaller and younger children (1,3). It is described that patients may spontaneously lose VPE during childhood (1), but the natural history of VPE is not well understood yet.

Purpose
To study the natural history of VPE. We focused especially on the likelihood of spontaneous resolution of VPE during growth, the possible associated factors, and the incidence of MAE during a long follow up in a contemporary paediatric cohort.

Methods
We retrospectively recruited patients diagnosed with VPE at age 0 to 12, referred from 1993 to 2021 to two tertiary care hospitals. Significant CHD and double AP were excluded. The primary outcome was the spontaneous resolution of VPE, defined by the loss of short PR and delta wave seen in at least two consecutive ECG and/or on 24-hour Holter monitoring. The follow up stopped when the patients reached 16 years of age, met the primary outcome or effective TCA was performed. Given the time-to-event dependency of the condition, the survival analysis of VPE considered the left truncation resulted from the recruitment of patients after the first days of life.

Results
We recruited 153 patients with a median age of diagnosis of 4.9 (0.2 – 8.4). The median follow-up time was 4.9 (1.6 – 8) years. During follow-up, 42 (28%) patients spontaneously loss VPE. The left truncated Kaplan-Meier survival curve of VPE is shown in Picture 1. It estimates that VPE would persist in 53% (40.1-70.2) and 33.8% (23.7-48.4) of patients at the age of 1 and 16, respectively. Symptoms and intermittent preexcitation were the only variables significantly associated with lower (OR 0.2) and higher probability (OR 3.45) of SR of VPE. The vast majority of patients with symptoms was treated with drug therapy before the age of 8, and TCA was safely delayed thereafter. None of the patients experienced a MAE during follow up.

Conclusion
According to our data, a large proportion of paediatric patients are likely to spontaneously lose VPE within the first year of life, and a spontaneous resolution may occur later during childhood in a non-negligible number of cases. The absence of symptoms and/or intermittent preexcitation are significant predictors of loss of VPE. The results of our study are of the utmost clinical relevance, since they support a wait-and-see strategy, especially in very young children with VPE.