Impact of contact-pressure based Hotballoon ablation of atrial fibrillation

Effective pulmonary vein isolation (PVI) using HotBalloon ablation requires adequate tissue contact, but no objective index currently exists to assess contact quality. We assessed balloon contact pressure (BCP) by measuring the difference in intra-balloon pressure before and after PV contact, using a pressure transducer connected to the balloon catheter shaft. In Phase 1, we retrospectively analyzed BCP in 25 patients (95 PVs) and compared the values between successful and unsuccessful single-shot PVI cases. Receiver operating characteristic analysis determined optimal cutoff values. In Phase 2, ablation was performed only when BCP exceeded the optimal threshold identified in Phase 1. BCP was significantly higher in successful PVI cases for both left superior pulmonary veins (LSPVs) (86.0 ± 27.0 mmHg vs. 24.3 ± 16.1 mmHg, P < 0.001) and non-LSPVs (61.1 ± 22.3 mmHg vs. 24.8 ± 18.6 mmHg, P < 0.001). ROC analysis identified an optimal cutoff value of 40 mmHg for LSPVs and 35 mmHg for non-LSPVs. In Phase 2, the single-shot PVI success rate was 89.3% (25/28 PVs) for LSPVs and 97.6% (82/84 PVs) for non-LSPVs. In addition to sufficient BCP, contact width > 4.2 mm at the carina was also associated with successful PVI. During follow-up, atrial fibrillation recurrence was observed in a subset of patients; however, PV reconnection was infrequently observed among those undergoing repeat ablation. No cases of severe PV stenosis were observed. Intra-balloon pressure measurement can be a practical surrogate for balloon-tissue contact and may support a safe, effective, and potentially durable single-shot HotBalloon PVI.