Background

Catheter ablation (CA) is a safe and effective treatment option for atrial tachycardias (ATs). Patients with a d-transposition of the great arteries (d-TGA), that underwent an atrial switch operation by Mustard, are often predisposed to ATs. Data on the successful treatment of ATs in this specific cohort of patients are scarce.

Objective

The objective of this observational clinical trial was to assess the efficacy and safety of a novel, first-in-human approach for manuel-guided catheter ablation (CA) in comparison to an established method using remote magnetic navigation (RMN) in post-Mustard procedure patients with ATs.  Additionally, the study aimed to evaluate patients’ long-term arrhythmia-free survival.

Methods

This study analyzed data from consecutive patients who had undergone Mustard’s operations and subsequently received either RMN- or manual-guided ablations for symptomatic ATs between 2016 and 2023. The novel CA approach consists of trans-baffle access and the creation of an ablation line connecting the tricuspid valve (TV) to the right inferior pulmonary vein (RIPV) (Figure 1 and 2). The primary endpoint was defined as recurrence of ATs lasting longer than 30 seconds beyond a 3-month blanking period.

Results

A total of 15 consecutive patients (34.52 ± 09.58 years, 80% male) were included. Nine patients (60%, 87% male) underwent RMN-guided ablation without trans-baffle puncture, while six patients (40%) were treated with the new approach involving a trans-baffle puncture (TBP). Acute procedural success was achieved in all patients (n=15, 100%). No major complications were observed. Regarding procedural characteristics, the novel approach resulted in a significantly shorter procedure duration (TBP, 150.50 ± 18.48 min vs. RMN, 253.11 ± 46.24 min, p < 0.01), but significantly longer fluoroscopy times (TBP, 9.63 ± 3.70 min vs. RMN, 3.93 ± 2.05 min, p=0.01). AT-free survival was 56% in the RMN-cohort of patients (n=5) compared to 83% in the TBP- group (n=5) (p=0.580). Consistent with these findings, Kaplan-Meier plot analyses demonstrated a higher estimated 2.5-year arrhythmia-free survival in the TBP-cohort of patients compared to the RMN-group (log-rank p = 0.258).

Conclusion

The novel approach for ATs seems to be safe and effective. Beyond that, it resulted in significantly shorter procedure times and a trend towards improved long-term arrhythmia-free survival in the specific cohort of d-TGA patients with ATs following Mustard’s operation. Further studies are needed to validate these initial observations.

Figure 1: Fluoroscopy images of trans-baffle puncture and loop maneuver
Figure 2: The novel ablation line from the tricuspid valve (TV) to the right pulmonary vein (RIPV)