Cryo balloon ablation in the left atria and esophageal injury

Abstract

Esophagus to LA fistula formation is a devastating complication of LA RF circumferential ablation. It is proposed that cryo balloon ablation is a safer and more effective technology for the ablation of AF. In four dogs (35 2 Kg) we have examined the impact of cryo balloon ablation of both PVs and posterior LA tissues on the integrity of the esophagus. Total of 42 lesions were placed, at the average body temperature of 99 0.8 F, and average maximal catheter temperatures of -77 2 C that were applied for 2 min. The lowest average intra-esophageal temperatures of 94 1 F at the time of ablation were recorded by esophageal thermometer that was placed at the location of lowest temperature and closest proximity to the cryo balloon assessed by steep LAO and RAO fluoroscopy. Cryo ablations were applied above the mitral ring where the LA and the esophagus are in closest proximity. The lowest temperature was recorded during left inferior pulmonary veins and posterior LA wall ablation. Pathological evaluation of the external esophagus examined acutely and 1 week after ablation revealed circular hemorrhagic lesions in close proximity to each other with maximum diameter of 18.7 mm, with an elevated erythematous rim surrounding each lesion. Morphologically most lesions were in the serosa and the external muscular coat of the esophagus. All lesions were sectioned. Histologic evaluation documented loss of nuclei, loss of architecture and pyknosis of myocytes. In the 3-7 days old lesions, there was mild lymphocytic infiltration with damage involving the serosa, the external muscle layer and with mild focal damage to the inner muscle layer. Sub-mucosal glands and the mucosa were normal. Conclusion: Cryo balloon ablation of the inferior PVs and the posterior wall of the LA in this model does penetrate to the outer layers of the esophagus, however no transmural lesions were noted and esophagus structural integrity remained intact.