Nonfluoroscopic Versus Fluoroscopic Radiofrequency Catheter Ablation for Pediatric Atrioventricular Nodal Reentrant Tachycardia: A Comparative Study of Procedural Characteristics and Ablation Site

Chieh-Mao Chuang^1,2Pi-Chang Lee^1*I Hsin Tai^1,3,4Peng Ying Hsuan^1,5Wen-Po Fan^1,6YU-SHIN LEE⁷Ming-Chih Lin^1,8Sheng-Lin Jan^1,8Yun-Ching Fu^1,8Shih-ann Chen^10,11,9

• ¹Division of Pediatric Cardiology, Children's Medical Center, Taichung Veterans General Hospital, Taichung City, Taiwan
• ²Division of Cardiology, Department of Internal Medicine, Asia University Hospital, Taichung, Taiwan
• ³Department of Cardiology, China Medical University Children’s Hospital, Taichung, Taiwan
• ⁴Department of Pediatrics, College of Medicine, China Medical University, Taichung, Taiwan
• ⁵Division of Pediatric Cardiology, Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan
• ⁶Division of Pediatric Cardiology, Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
• ⁷Division of Pediatric Cardiology, Department of Pediatrics, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan, Taiwan
• ⁸Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung, Taiwan
• ⁹Cardiovascular Center, Taichung Veterans General Hospital, Taichung, Taiwan
• ¹⁰Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming Chiao-Tung University, Taichung, Taiwan
• ¹¹Division of Cardiovascular Medicine, Department of Medicine, China Medical University Hospital, China Medical University, Taichung, Taiwan

Nonfluoroscopic cryoablation is considered safe for pediatric atrioventricular nodal reentrant tachycardia (AVNRT), but concerns about prolonged procedures and recurrence persist, requiring continued use of radiofrequency ablation (RFA). Nonfluoroscopic RFA, guided by three-dimensional mapping, offers enhanced precision. This study compares its safety and effectiveness with fluoroscopic RFA in pediatric AVNRT.We retrospectively analyzed children undergoing RFA without (X-group) or with (X+ group) fluoroscopy at multiple centers (2011-2024). Patients who received fluoroscopic and threedimensional mapping guidance were excluded. Baseline characteristics, electrophysiological data, and ablation outcomes were compared.Among 119 patients (X+: 57, X-: 62), there was a significantly higher rate of successful ablation site in the lower triangle of Koch on 3D electroanatomical mapping (3D-EAM). However, the procedure time, the acute success rate, the recurrence-free survival of AVNRT, and the injury to the conduction system were similar between the groups. No permanent complete atrioventricular block was observed in either group. The longer procedure time was independently correlated with ablation location outside of the low Koch triangle, lower common pathway block, and slow pathway modification. Dual AV nodes without inducible tachycardia had lower AVNRT-free survival than typical and atypical AVNRT (80% vs. 96.5% vs. 100%, p=0.025). Younger children can achieve successful ablation with fewer ablation pulses and a smaller ablation catheter profile, with similar recurrence and conduction system injury.Nonfluoroscopic RFA, guided by 3D-EAM, achieves comparable acute and mid-term outcomes to fluoroscopic RFA in pediatric AVNRT. The successful site of slow pathway ablation was significantly lower when using 3D-EAM compared with fluoroscopy.