Ablation of Accessory Pathways in the Coronary Venous System in Patients ≤18 Years

Background: An accessory atrioventricular pathway (AP) is the most common tachycardia substrate for supraventricular tachycardia (SVT) in the young. Endocardial catheter ablation of posterior septal AP is unsuccessful in 5% of cases due to an epicardial location. Ablation to these pathways may be accomplished within the coronary venous system (CVS). Data of AP ablation within the CVS in the young is sparse. We analyzed feasibility, outcome, and safety in all patients ≤18 years of age with epicardial AP and ablation via CVS in our tertiary pediatric referral center. Results were compared with patients who had endocardial AP ablation from the European Multicenter Pediatric Ablation Registry “EUROPA.”

Method: Data of all patients ≤18 years of age who had AP ablation within the CVS (RF and Cryo) in our center between May 2003 and December 2021 were analyzed. The control group was generated and adjusted for age, weight, and pathway location from the “EUROPA” Registry.

Results: A total of 24 individuals (female: 12; 50%) had ablation of an AP within the CVS. Median age was 12.3 (range: 2.7–17.3) years, median weight was 43.8 (range: 15.0–72.0) kg. 22 of 24 patients (92%) had a structurally normal heart. The control group consisted of 50 individuals (female: 21; 42%) at a median age of 10.0 (range: 0–17) years and a median weight of 36.4 (range: 6.2–73.0) kg. Age and weight were not different between the groups. In all cases, electroanatomical 3D mapping systems were used. In 2 of 24 study patients (8%), the AP was not ablated due to close proximity to a coronary artery (CA). Success was achieved in 20 of 22 individuals (91%). In the control group, success of AP ablation was 98% (49/50). A total of two major complications were noted (2/22, 9%) in the CVS group. Both individuals had evidence of CA injury after RF ablation (temporary = 1, permanent = 1). During median follow-up of 8.5 (range: 0.1–17.2) years, 5/22 (23%) patients had repeat SVT after a median of 3.3 (range: 0.1–12.4) years. 5 of 4 patients had successful repeat ablation. All five patients with SVT recurrence had posteroseptal AP. According to the protocol of EUROPA, controls had a follow-up of 12 months. Tachycardia recurrence was reported in 1 of 50 (2%).

Conclusion: In our study group, the success of epicardial AP ablation was lower when compared to endocardial AP ablation. There was a substantial risk of CA injury. To avoid CA injury when ablating within the CVS near CA, the distance between the ablation site and CA should be clarified before ablation. Data should be taken into account when epicardial AP ablation is performed in the young.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
28 January 2023