Efficacy of three-dimensional electroanatomic mapping-guided minimally invasive transaxillary atrial appendage resection for focal atrial tachycardia originating from the atrial appendage in children.

Objectives: To investigate the clinical characteristics and short-to-medium-term outcomes of minimally invasive transaxillary atrial appendage resection guided by the Carto3 three-dimensional electroanatomic mapping system for focal atrial tachycardia originating from the atrial appendage (atrial appendage tachycardia, AAT) in children. Methods: This single-center retrospective study consecutively enrolled 27 children with atrial tachycardia (AT) who underwent Carto3-guided electrophysiologic study between January 2023 and April 2026; 6 (22.2%) were confirmed to have AAT. Treatment was individualized according to anatomical origin: minimally invasive transaxillary appendage resection for appendage tip origin or aneurysm ( Results: All six patients (four male, 66.7%; mean age 10.28 ± 3.49 years) showed Carto3 activation patterns suggestive of focal origin. The earliest activation was at the appendage tip in 5 (83.3%) and at the base in 1 (16.7%); 5 (83.3%) had incessant AT; and 3 (50%) had tachycardia-induced cardiomyopathy (TIC). Appendage resection group ( Conclusions: In this small preliminary series, one-stop minimally invasive transaxillary appendage resection showed initial feasibility and favorable short-term outcomes in pediatric AAT with Carto3-confirmed appendage tip origin or associated aneurysm refractory to medical therapy. TIC secondary to AAT may be reversible after arrhythmia elimination. These preliminary findings require validation in larger, multicenter, prospective studies. The role of PFA in pediatric AAT warrants further investigation.