Esophagus Imaging for Radiofrequency Ablation of Atrial Fibrillation

Percutaneous catheter ablation with circumferential pulmonary vein isolation using radiofrequency energy has become an important therapeutic option to treat atrial fibrillation over the last years. Importing images from pre-acquired 3-D CT or MRI scans into the 3-D mapping system with superimposition of the electro-anatomical map is increasingly used. Despite these advances, the interventional electrophysiologist must be aware of potential complications that are associated with this procedure. As the left atrium is in close vicinity to the esophagus, radiofrequency ablation in the left atrium may damage the esophagus and create esophageal perforations and esophageal left atrial fistula. To prevent this lethal complication integration of an esophagus tag into the electroanatomic left atrium map visualizing the anatomic relationship has been studied und reported. Another possibility of visualization of the esophagus is to perform the CT after placing a conventional radio-opaque gastric tube, which provides information about the course of the esophagus in relation to the LA and may be scanned by CT . It has been shown that under normal conditions, if no barium is administered, there is little change in the anatomical relationship between the posterior left atrium and the esophagus during the entire cardiac cycle. However it is not clear whether the position of the esophagus in relation to the left atrium is changing over days.

The aim of the present study is to evaluate whether visualization of the esophagus by placing a conventional gastric tube before performing the CT scan and visualization and integration of the esophagus into the 3-D electro-anatomical map the day before ablation is accurate compared with integration of an esophagus tag into the electroanatomic left atrium map visualizing the anatomic relationship during the radiofrequency ablation.