Key result
Low-power RF ablation successfully eliminates pediatric concealed para-Hisian pathway without AV block.
Why the study?
Catheter ablation of concealed para-Hisian accessory pathways in very young children is technically demanding and carries a substantial risk of atrioventricular block because of small cardiac dimensions and inability to use pre-excitation mapping.
Does low-power, temperature-controlled radiofrequency catheter ablation safely and effectively eliminate a concealed para-Hisian accessory pathway in a 3-year-old child?
Case Report (n=1)
No
Does low-power, temperature-controlled radiofrequency catheter ablation safely and effectively eliminate a concealed para-Hisian accessory pathway in a 3-year-old child?
This case report demonstrates that low-power, temperature-titrated radiofrequency catheter ablation guided by precise activation mapping can safely and effectively eliminate a high-risk concealed para-Hisian accessory pathway in a 3-year-old toddler without causing atrioventricular block.
May support low-power RF ablation for concealed para-Hisian pathways in young children; leaves open durability and generalizability.
Background: Catheter ablation of para-Hisian accessory pathways (PHAP) in children is technically demanding and carries a substantial risk of atrioventricular (AV) block. This risk is magnified in very young patients, in whom small cardiac dimensions place the AV node and His bundle in close anatomical proximity to the ablation target. Concealed PHAP cannot be localized by pre-excitation mapping, further increasing procedural difficulty. We report a 3-year-old girl with a concealed para-Hisian accessory pathway, representing two high-risk features: very young age and an ablation target immediately adjacent to the His bundle. Case summary: A 3-year-old girl presented with recurrent paroxysmal tachycardia. Electrophysiological study confirmed orthodromic atrioventricular reentrant tachycardia mediated by a concealed para-Hisian accessory pathway. Activation mapping during tachycardia identified the earliest retrograde atrial activation adjacent to the His bundle at the 12 o’clock position of the tricuspid annulus. Radiofrequency energy was delivered in temperature-controlled mode at 25 W with a maximal target temperature of 45°C; tachycardia terminated within 3 seconds, followed by 60 seconds of consolidation ablation at identical parameters. No accelerated junctional rhythm or AV conduction deterioration was observed during energy delivery. Post-ablation, ventriculoatrial dissociation was documented, and no permanent AV conduction disturbance occurred. The patient remained free of arrhythmia-related symptoms at 2-week and 1-month follow-up. Conclusions: : This case demonstrates that radiofrequency catheter ablation can be performed safely and effectively in selected very young children with concealed septal accessory pathways. Success depends on meticulous activation mapping, stable catheter-tissue contact, and individualized low-power, temperature-titrated energy delivery. Additional multicenter experience is required to validate long-term safety and efficacy in this population.
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Li et al. (2026) conducted a case report in Orthodromic atrioventricular reentrant tachycardia mediated by a concealed para-Hisian accessory pathway (n=1). Low-power temperature-controlled radiofrequency catheter ablation was evaluated on Acute elimination of accessory pathway conduction and freedom from arrhythmia recurrence without AV block. Low-power (25 W, 45°C) radiofrequency catheter ablation terminated tachycardia within 3 seconds in a 3-year-old with a concealed para-Hisian pathway, achieving 1-month arrhythmia freedom without AV block.
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