Catheter ablation approach targeting epicardial connections to the right pulmonary vein antrum detected before pulmonary vein isolation

Background

Epicardial connections from surrounding structures to the right pulmonary vein (PV) antrum impede PV isolation.

Objective

This study aimed to evaluate the efficacy of an ablation approach targeting epicardial connections for right PV isolation.

Methods

We prospectively enrolled 124 patients with atrial fibrillation undergoing initial PV isolation. We identified the activation breakthrough into the right PV antrum (BT-RPV) on the activation map created during high right atrial pacing before PV isolation. BT-RPV sites were targeted when right PV isolation was not achieved by wide antral circumferential ablation (WACA).

Results

BT-RPV was observed in 83 patients (67%). PV isolation was achieved by WACA in all 41 patients without BT-RPV. Among patients with BT-RPV, PV isolation was achieved by WACA in 48 patients when all BT-RPV sites were covered by the PV isolation line. Conversely, PV isolation was completed by WACA in only 5 of 35 patients when not all BT-RPV sites were covered. In patients where WACA failed, 35 sites were targeted for BT-RPV ablation. Initial BT-RPV ablation led to PV isolation at 20 sites, while the remaining 15 BT-RPV sites required repeat BT-RPV ablation. The ablated area of successful BT-RPV ablation was 0.9 (0.6–1.2) cm², corresponding to the area activated within 15 (14–16) ms after BT-RPV emergence. Ablating the area activated within 14 ms of BT-RPV emergence was associated with successful PV isolation (sensitivity 91%; specificity 100%).

Conclusion

Ablation targeting BT-RPV sites is effective for right PV isolation. Extensive ablation is required to eliminate BT-RPV.