Endoscopic Pulmonary Vein Ablation for Atrial Fibrillation: A Giant Step Forward

Denise W Gee, MD, Alex Escalona, MD, Katherine H Briggs, Brian G Turner, MD, Patricia Sylla, MD, William R Brugge, MD, David W Rattner, MD. Harvard Medical School, Massachusetts General Hospital

INTRODUCTION: Endovascular pulmonary vein (PV) ablation is time-consuming and can require significant fluoroscopic exposure. Current surgical methods of treating atrial fibrillation are more effective, but invasive and painful. A subxiphoid flexible endoscopic approach to PV ablation through a small incision could offer more direct access to the mediastinum resulting in shorter procedure times and less pain. The first step to proving feasibility of this technique is the successful circumferential dissection of all PVs using endoscopic instruments.
METHODS AND PROCEDURES: A feasibility study was performed in 6 cadavers. In each cadaver, a small subxiphoid incision was created and a double-lumen gastroscope was inserted into the mediastinum. The pericardium was incised to access the posterior wall of the heart. Identification of the inferior vena cava (IVC), superior/inferior right PVs, and superior/inferior left PVs was attempted. Next, circumferential dissection of all identified PVs was performed using flexible endoscopic instruments. Upon completion of the procedure, a median sternotomy was performed and the accuracy and completeness of the endoscopic dissection assessed.
RESULTS: A significant learning curve was present. The IVC was easily identified in all cadavers. As experience increased, the number of circumferentially dissected PVs increased and the total operative time decreased. Postprocedure median sternotomy confirmed the accuracy of all identified structures and the completeness of all vessel dissection.

CONCLUSIONS: Endoscopic circumferential dissection of all four pulmonary veins is feasible in the cadaver model. Identifying the optimal approach is an important step in testing the feasibility of flexible endoscopic PV ablation. Further studies are underway to evaluate endoscopic ablative devices on live animal models.