CONGRESS ABSTRACT

Background. Ventricular pre-excitation, affecting 0.1-0.3% of the general population. This condition can lead to re-entrant tachyarrhythmias and, in rare cases, sudden cardiac death, even in asymptomatic individuals. Catheter ablation of accessory patway is often the resolutive treatment, however, in the pediatric population, it must be performed at highly experienced centers. Long-term outcome data of zero-fluoroscopy catheter ablation of accessory patway in children is less robust due to fewer systematic studies compared to the adult population. Methods. This retrospective study evaluates the long-term efficacy of zero-fluoroscopy catheter ablation for ventricular pre-excitation in 143 patients with an average age of 12+/-3 years who underwent radiofrequency ablation at a single tertiary center. Before the procedure, all patients underwent a comprehensive echocardiographic assessment. Results. The acute success rate was 83% (119/143) for the first ablation attempts reaching 88% (127/143) after the second procedure. Right-sided pathways were associated with higher acute failure hazard (HR 3.41, 95% CI 1.41–8.22; p=0.006), particularly right antero-midseptal sites carried a large increment of acute failure (HR 9.55, 4.22–21.60; p<0.001). The left-sided pathways were associated with lower acute failure hazard (HR 0.29, 0.12–0.71; p=0.006). Congenital heart disease was also associated with increased acute failure risk (HR 4.01, 1.20–13.47; p=0.025). No major mid- or long-term complications were reported. After a successful ablation, during a median follow-up of 52 months, 15 patients out of 127 (12%) experienced a relapse of AP conduction. Recurrences were more frequent within the first month post-procedure and showed a border-line association with right-sided pathways (HR 2.73, 0.97–7.69; p=0.057) and a significative association with multiple accessory pathways (HR 4.45, 1.41–13.98; p=0.011). Late recurrences (beyond one year) were rare and located on the left side. All fifteen patients underwent a re-do ablation procedure with a 50% success rate. Conclusions. Long-term freedom from accessory pathway conduction was achieved in 88% of cases. Zero-fluoroscopy catheter ablation of accessory pathways is a safe and effective in pediatric patients. While the rigth location of the accessory pathway and the presence of congenital heart diseases can affect the success of the initial ablation, long-term outcomes are generally favorable.