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°C vs. 1.2 ± 1.1°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.

Keywords: Catheter ablation, Esophageal injury, Phrenic nerve injury

Abbreviations: AF, atrial fibrillation, CIPV, common inferior pulmonary vein, EA, electroanatomic, ECG, electrocardiogram, IPBP, intrapericardial balloon placement, LA, left atrium, PN, phrenic nerve, PV, pulmonary vein, RF, radiofrequency, RSPV, right superior pulmonary vein, VT, ventricular tachycardia