DISCUSSION
Centrifugal activation with widespread breakthrough suggested that the activation originated from epicardial structures.2,3Considering the location of the breakthrough site, it was likely that the PACs originated from the Bachmann bundle or its branches.3 Extensive ablation was deemed necessary to eliminate these PACs if we targeted the widespread breakthrough. Therefore, despite the local potentials in the right PV being later than those in the anterior wall, we performed wide antral circumferential ablation (WACA) for the right PV to disconnect the PAC origin from the anterior wall (Fig. 3A). Following the completion of right PV isolation, PACs were eliminated, and frequent ectopic beats were observed in the right PV (Fig. 3B). These ectopic beats originated from the antrum of the right superior PV. Additional ablation targeting these ectopic beats was performed; however, they were not completely eliminated. To prevent PV stenosis, further ablation was avoided. The patient was discharged two days post-procedure without any complications, and no recurrence of PACs has been observed over a 28-month follow-up period.
In our retrospective analysis of the baseline left atrial map, we identified a small, blunt prepotential localized to the area associated with the proximal Bachmann bundle (Fig. 3A). We considered this prepotential to represent the far-field sensing of the PAC origin within the proximal Bachmann bundle. In this case, PACs were eliminated during right PV isolation. This phenomenon can likely be attributed to the disruption of the electrical connection between the PAC origin and the distal Bachmann bundle. Additionally, we observed ectopic beats originating from the antrum of the right superior PV after WACA. The disruption of the preferential conduction pathway toward the distal segment of the Bachmann bundle may have unveiled electrical connections between the proximal segment of the Bachmann bundle and the antrum of the right superior PV.
It remains uncertain whether our strategy of isolating the PAC origin in the Bachmann bundle through WACA is applicable to all similar cases, as ablating epicardial structures such as the Bachmann bundle via endocardial ablation poses challenges. However, this case provides critical insights into ablation strategies for PACs originating from epicardial structures like the Bachmann bundle.