Pilot study of transesophageal endoscopic epicardial coagulation by submucosal endoscopy with the mucosal flap safety valve technique (with videos)

Background: We previously demonstrated that the thoracic cavity could be safely accessed by submucosal endoscopy with the mucosal flap safety valve (SEMF) technique. Objectives: To evaluate the technical feasibility of transesophageal access to the heart and epicardial ablation. Design: One-week survival study with 5 porcine models. Settings: Animal laboratory with general anesthesia. Interventions: High-pressure carbon dioxide injection and balloon dissection created a large submucosal working space for insertion of a cap-fitted endoscope. A myotomy was performed inside the submucosal space. The thoracic cavity was endoscopically accessed through the myotomy site. A pericardial window was created with a needle-knife. A spot coagulation of the epicardium was performed with a heat probe and a hook-knife. The myotomy site was sealed with the overlying mucosal flap, and the mucosal entry site was closed with clips. Main Outcome Measurements: An endoscopy and a necropsy were performed to study the esophagus, mediastinum, pericardial space, and cautery locations on the epicardium one week after the procedure. Results: Epicardial coagulation was successfully performed within 30 minutes in 4 of the 5 pigs. Follow-up endoscopy demonstrated completely sealed myotomy sites by the overlying mucosal flap. There was no gross contamination or signs of contamination in the thoracic cavity. The pericardial space was normal in appearance. The epicardial coagulation sites were healing, without exudative ulceration. Conclusions: The SEMF technique allowed endoscopic access to the upper mediastinum, the pericardium, and the epicardium via the esophagus, along with a minimal intervention on the epicardium.