Intrapericardial balloon placement for prevention of collateral injury during catheter ablation of the left atrium in a porcine model

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). OBJECTIVES 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