Ablation outcomes in children with Mahaim tachycardia using the TactiCath contact force catheter

Abstract Introduction: Mahaim ablation poses a significant challenge among accessory pathway ablations. This study aims to present our findings on Mahaim ablation performed using a contact force catheter, emphasizing both the effectiveness and safety of this technique. Materials and methods: This is a single-centre retrospective cohort study. Twenty-two consecutive patients who underwent Mahaim pathway ablation procedures between January 2017 and January 2025 were included in the study. The EnSite Precision System (Abbott, St. Paul, MN, USA) was used to facilitate mapping and to reduce or eliminate the need for fluoroscopy. Ablation was performed using the TactiCath catheter. Results: The median age was 11 years (range: 7–18). Antidromic tachycardia was induced in all patients with the left bundle block. All patients underwent successful ablation with the TactiCath catheter. Ablation was performed via the jugular approach in 11 patients and via the femoral region in another 11 patients. Ablation procedures were performed under atrial pacing in four patients regarding catheter stabilization. Locations of the Mahaim signals were at the right anterolateral ( n = 6), right lateral ( n = 7), and right posterolateral ( n = 9) tricuspid annulus. The acute success rate was 100% (22/22). Fluoroscopy was not used on any patient. The median procedure time was 132 minutes (range: 72–411). No major complications were observed. One recurrent patient who presented with a tachycardia attack one month later had Ebstein’s anomaly. An ablation procedure was successfully performed from the right lateral region. Conclusion: In paediatric Mahaim tachycardia ablations, the use of a contact force catheter can be safe and successful.