Objective:

To evaluate 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 in children.

Approach:

• Study Design: Single-center retrospective study enrolling pediatric patients with atrial tachycardia who underwent Carto3-guided electrophysiologic study.
• Patient Enrollment: 27 children were enrolled, with 6 confirmed cases of atrial appendage tachycardia.
• Treatment Methods: Minimally invasive transaxillary appendage resection for 5 patients and pulsed field ablation for 1 patient.

Key Findings:

• All 6 patients (4 male, mean age 10.28±3.49 years) showed Carto3 activation mapping patterns suggestive of focal origin.
• Immediate atrial tachycardia termination and sinus rhythm restoration were achieved in all 5 patients who underwent appendage resection.
• No recurrence or procedure-related complications were observed in the appendage resection group at a median follow-up of 13 months.
• The single patient in the pulsed field ablation group experienced recurrence of atrial tachycardia at 1 month.
• In patients with tachycardia-induced cardiomyopathy who underwent appendage resection, left ventricular ejection fraction improved from 46.3% to 62.0%.

Interpretation:

Minimally invasive transaxillary appendage resection appears feasible with favorable short-term outcomes for children with atrial appendage tachycardia.

Limitations:

• Small sample size of only 6 patients.
• Lack of intergroup comparison between surgical and pulsed field ablation groups.
• Preliminary findings require validation in larger, multicenter, prospective studies.

Conclusion:

These preliminary findings suggest that minimally invasive transaxillary appendage resection may be effective for children with atrial appendage tachycardia.