title: Feasibility of endoscopic guidance for nonsurgical transthoracic atrial and ventricular epicardial ablation.
abstract: BACKGROUND
  Epicardial catheter ablation via subxiphoid percutaneous access currently is used upon failure of endocardial catheter ablation. The safety, efficacy, and applicability of epicardial catheter ablation likely will improve with direct visualization of the pericardial space.
  
  
  OBJECTIVE
  The purpose of this study was to assess the feasibility of percutaneous endoscopic guidance for identification of epicardial anatomic landmarks and epicardial catheter ablation.
  
  
  METHODS
  Dual subxiphoid epicardial access and femoral venous and arterial access were obtained in six healthy swine. The endoscope and electrophysiology catheter were advanced to the pericardial space. Anatomic landmarks were identified via endoscopy and confirmed by multiview fluoroscopic assessment of proximity to endocardial catheters in the area of interest. Radiofrequency ablation of selected anatomic targets was performed under endoscopic guidance. Targeting of lesions was assessed by pathologic examination of the target and surrounding structures.
  
  
  RESULTS
  Dual large-bore subxiphoid epicardial access was obtained without complications in all animals. The coronary sinus, left anterior descending coronary artery, left atrial appendage, and pulmonary veins were easily visualized in all animals. Catheter ablation of anatomic targets, including the right ventricular outflow tract, left atrial appendage, and pulmonary veins, was performed successfully under direct endoscopic observation. Endoscopic guidance of point and linear lesions near coronary vessels also was assessed. Pathology revealed successful targeting of lesions.
  
  
  CONCLUSIONS
  Endoscopic guidance of percutaneous epicardial electrophysiologic procedures is feasible. Direct visualization of epicardial structures, catheters, and lesions may improve the safety and efficacy of epicardial catheter ablation and reduce staff and patient radiation exposure.
authors.affiliation: Department of Medicine, Division of Cardiology, Johns Hopkins Hospital, Baltimore, Maryland 21287, USA. snazarian@jhmi.edu
authors.forename: Saman
authors.initials: S
authors.lastname: Nazarian
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Kantsevoy
authors.forename: Menekhem M
authors.initials: MM
authors.lastname: Zviman
authors.forename: Fredrick A
authors.initials: FA
authors.lastname: Matsen
authors.forename: Hugh
authors.initials: H
authors.lastname: Calkins
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Berger
authors.forename: Henry R
authors.initials: HR
authors.lastname: Halperin
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D004452:Echocardiography / Q000295:instrumentation*; D005240:Feasibility Studies; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000601:surgery*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000601:surgery*; D010496:Pericardium / Q000000981:diagnostic imaging / Q000601:surgery*; D013552:Swine; D013906:Thoracoscopy / Q000379:methods