Electrophysiological Findings Following Surgical Thoracoscopic Atrial Fibrillation Ablation

Background Hybrid ablation (a combination of thoracoscopic epicardial ablation followed by catheter ablation) has become a new technique for AF treatment. Objective To evaluate the success and electrophysiological follow-up after using the COBRA Fusion device to deliver a circumferential lesion set anterior to the pulmonary veins in attempt to isolate the posterior LA (box isolation). Methods Surgical ablation was carried out via thoracoscopic approach using COBRA Fusion radiofrequency catheter. An EP study was done 2 – 3 months later to verify box isolation (and to complete it, if needed) and to perform right sided isthmus ablation. Fat thickness along the presumed box lesion line was measured using pre-procedural CT. Results Thirty patients (age 60.0 ± 11.6 years, 22 males, 8 with long-standing and 22 with persistent AF) were enrolled. The duration of the EP study was 216.3 ± 64.2 min. Box isolation, based on the EP study, was complete in 12 (40%), and incomplete in 18(60%) patients. Successful box isolation was achieved with a catheter ablation in 16 of 18 patients (89%). A total of 39 gaps in these 16 patients were identified. Typical gap locations were the anterior-superior part of the superior pulmonary veins and the roof line. The fat thickness along the roof line was substantially higher compared to the inferior line. (4.58±1.61 mm vs. 2.37±0.76 mm, p < 0.001). Conclusion There is a relatively low rate of complete isolation using the COBRA catheter ablation system. The superior line and anterior parts of superior PVs have most conduction gaps.