Pulsed-Field Ablation of Atrial Tachycardia Originating From Bachmann's Bundle Via Epicardial Approach

BACKGROUND: Pulsed-field ablation (PFA) may be effective for atrial tachycardia (AT) originating from Bachmann's bundle via epicardial mapping, but no such cases have been reported. CASE SUMMARY: A 40-year-old man with recurrent AT postatrial fibrillation ablation underwent repeat ablation with a focal PFA catheter. Activation mapping identified the earliest activation site at the Bachmann's bundle insertion in the left atrium, but PFA there was ineffective. Following pericardial puncture, the earliest activation point was mapped on the epicardial side at the corresponding endocardial Bachmann's bundle insertion site, 5.5 mm from the endocardial point. A single epicardial PFA application (1800V, 5 trains) immediately terminated the AT. However, AT recurred the next day, requiring radiofrequency ablation, after which it recurred again. DISCUSSION: This case demonstrates that PFA can successfully ablate refractory AT originating from epicardial Bachmann's bundle, but lesion depth may be limited by tissue thickness and epicardial fat, affecting long-term durability. TAKE-HOME MESSAGES: PFA could terminate epicardial Bachmann's bundle-mediated AT when endocardial ablation fails, but recurrence may occur due to limited lesion depth influenced by epicardial fat and tissue thickness. This suggests that the efficacy of PFA in thick-walled tissues remains somewhat constrained.