Visual Balloon-Guided Point-by-Point Ablation: Reliable, Reproducible, and Persistent Pulmonary Vein Isolation

Background—While conceptually straightforward, placing point-to-point contiguous radiofrequency lesions to achieve pulmonary vein isolation (PVI) is technically challenging in patients with paroxysmal atrial fibrillation. Furthermore, chronic efficacy is limited by late PV reconnections. A novel compliant balloon ablation catheter able to deliver visually guided short arcs/spots of laser energy was tested in initial preclinical and clinical cases to determine if visual guidance could predict reliable and persistent PVI. Methods and Results—This study consisted of (1) an experimental porcine phase with both acute (n=15 pigs) and 4-week chronic (n=10) data and (2) a single-center clinical feasibility phase (n=27 patients with paroxysmal atrial fibrillation), again with acute and 3-month chronic data. Under endoscopic guidance, point-by-point perivenous ablation was performed in a contiguous and overlapping manner. Each porcine PV was longitudinally sectioned for detailed histological analysis. At 3 months after ablation, patients underwent a prespecified remapping procedure regardless of symptomotology. In the acute and chronic animals, 29 of 30 (97%) PVs were electrically isolated after placing the initial circumferential lesion set. For the 4-week chronic animals, 80% of PVs remained isolated; lesions were histologically circumferential in 120 of 120 (100%) PV sections and transmural in 116 of 120 (96.7%) PV sections (average transmurality=99.0±5.5%). In patients, 100% of the PVs were isolated after 1.3 attempts per PV—84% of them (85 of 101) isolated after the initial visually guided lesion set. At 3 months, 61 of 68 (90%) PVs continued to be electrically isolated. Conclusions—Using a visually guided, compliant balloon ablation catheter with point-by-point ablative capability, PV isolation can be achieved in a reliable, reproducible, and persistent manner.