title: Intrapericardial balloon placement for prevention of collateral injury during catheter ablation of the left atrium in a porcine model.
abstract: BACKGROUND
  Catheter ablation of the left atrium (LA) is associated with potential collateral injury to surrounding structures, especially the esophagus and the right phrenic nerve (PN).
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the efficacy and feasibility of intrapericardial balloon placement (IPBP) for the protection of collateral structures adjacent to the LA.
  
  
  METHODS
  Electroanatomic mapping was performed in porcine hearts using a transseptal endocardial approach in eight swine weighing 40-50 kg. An intrapericardial balloon was inflated in the oblique sinus, via percutaneous epicardial access, to displace the esophagus. Similarly, with the balloon positioned in the transverse sinus, IPBP was used to displace the right PN. Esophageal temperature was monitored while endocardial radiofrequency (RF) energy was delivered to the distal inferior PV.
  
  
  RESULTS
  In all cases, balloon placement was successful with no significant effects on hemodynamic function. Balloon inflation increased the distance between the esophagus and posterior LA by 12.3 +/- 4.0 mm. IPBP significantly attenuated increases in luminal esophageal temperature during endocardial RF application (6.1 +/- 2.4 degrees C vs. 1.2 +/- 1.1 degrees C; P<.0001). High-output endocardial pacing from the right superior pulmonary vein ostium stimulated PN activity. After displacement of the right PN with IPBP, PN capture was abolished in 30 (91%) of 33 sites.
  
  
  CONCLUSIONS
  These findings demonstrate that in an animal model, IPBP is feasible in the setting of catheter ablation procedures and has the potential to decrease the risk of collateral damage to the esophagus and PN during LA ablation.
authors.affiliation: David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.
authors.forename: Shiro
authors.initials: S
authors.lastname: Nakahara
authors.forename: Rafael J
authors.initials: RJ
authors.lastname: Ramirez
authors.forename: Eric
authors.initials: E
authors.lastname: Buch
authors.forename: Yoav
authors.initials: Y
authors.lastname: Michowitz
authors.forename: Marmar
authors.initials: M
authors.lastname: Vaseghi
authors.forename: Carlos
authors.initials: C
authors.lastname: de Diego
authors.forename: Noel G
authors.initials: NG
authors.lastname: Boyle
authors.forename: Aman
authors.initials: A
authors.lastname: Mahajan
authors.forename: Kalyanam
authors.initials: K
authors.lastname: Shivkumar
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017115:Catheter Ablation / Q000009:adverse effects*; D002404:Catheterization; D004947:Esophagus / Q000293:injuries*; D005240:Feasibility Studies; D006325:Heart Atria / Q000601:surgery*; D006439:Hemodynamics; D010496:Pericardium; D010791:Phrenic Nerve / Q000293:injuries*; D013552:Swine; D014947:Wounds and Injuries / Q000517:prevention & control