Pericardial-esophageal fistula complicating cryoballoon ablation for refractory atrial fibrillation

Atrial fibrillation affects an estimated 2.7–6.1 million people in the United States and accounts for more than 750,000 hospitalizations per year. Pulmonary vein isolation (PVI) has been well established as the most effective ablation treatment available for patients with symptomatic and medication-refractory atrial fibrillation. Previously, radiofrequency (RF) ablation was the mainstay for PVI. However, this was not without complications, which have been well documented, the most feared complication being atrioesophageal fistula formation, which carries an estimated 0.01%–0.25% risk and an estimated mortality of 60%– 75%. The introduction of cryoballoon (CB) ablation therapy changed the landscape of treatment as it made PVI easier, faster, and, presumably, safer compared with RF. The first generation of cryoballoons showed an improved safety profile with regard to esophageal damage; in fact, the first case report of an atrioesophageal fistula with the firstgeneration CB was not reported until 2012 and Medtronic, Inc reportedly has only noted 3 atrioesophageal fistulas in 35,000 cases with the first-generation balloon. A secondgeneration CB has been developed to improve PVI by creating larger and more homogenous areas of freezing with more uniform cooling and provide better pulmonary vein isolation. This second-generation CB carries a similar esophageal risk profile, and studies have shown healing of these esophageal thermal lesions (ETLs) without fistula formation. Nonetheless, there have been 5 reported cases of atrioesophageal fistula formation with the use of CB ablation to date. However, there have not been any known reported cases of pericardial-esophageal fistula