Dear Editor,

Von Bergen and colleagues report a valuable multicentre randomised evaluation of voltage-propagation versus anatomical mapping for paediatric atrioventricular nodal re-entry tachycardia ablation. Their study addresses a clinically relevant question in a field where comparative prospective data are limited, and its multicentre design, intention-to-treat framing, and follow-up beyond the index procedure are notable strengths. ^{Reference Von Bergen, Zhang, Kilinc, Kean, Johnsrude and Law1}

Several methodological features, however, warrant a more cautious interpretation. First, although the trial was randomised, the interventions were only partially standardised. In the voltage-propagation arm, mapping thresholds, point density, catheter type, and final lesion choice were left largely to operator discretion; in the anatomical arm, electrogram features could also influence targeting. This makes the comparison closer to two pragmatic operator-dependent strategies than to two tightly defined interventions. CONSORT 2025 emphasises transparent reporting of allocation methods, intervention details, protocol deviations, and analysis populations precisely because such factors materially affect interpretability. ^{Reference Hopewell, Chan and Collins2}

Second, the study population was heterogeneous. Patients with typical atrioventricular nodal reentrant tachycardia (AVNRT), atypical AVNRT, and jump/echo physiology without inducible AVNRT were analysed within the same randomised framework, even though the manuscript itself suggests these substrates differ in lesion burden and recurrence. In addition, ablation energy source was not randomised, and crossover between mapping strategies occurred in 9 of 70 cases. Under such conditions, an intention-to-treat analysis remains appropriate, but crossover-related dilution of between-group differences should be acknowledged more explicitly, and interpretation benefits from distinguishing assignment effects from adherence-sensitive effects. ^{Reference Molero-Calafell, Burón, Castells and Porta3}

Third, the conclusion that both techniques produced similar outcomes may overreach the available evidence. A small trial without a clearly reported power calculation or a predefined noninferiority/equivalence framework cannot establish comparability merely on the basis of non-significant P values. Methodological guidance on noninferiority trials has stressed that absence of statistical significance is not evidence of therapeutic equivalence and that the trial objective must be specified and matched to design and analysis. ^{Reference Tweed, Quartagno and Clements4}

These issues do not negate the study’s contribution. Rather, they suggest that the findings are best viewed as hypothesis-generating evidence that both approaches are feasible in experienced hands, while a more definitive comparison would require stricter intervention standardisation, clearer reporting of randomisation and crossover handling, and design features aligned with an explicit superiority or noninferiority question.