The Extent of Mechanical Esophageal Deviation to Avoid Esophageal Heating During Catheter Ablation of Atrial Fibrillation.

OBJECTIVES: This study sought to determine the extent of lateral esophageal displacement required during mechanical esophageal deviation (MED) and to eliminate luminal esophageal temperature elevation (LETElev ) during pulmonary vein (PV) isolation.

BACKGROUND: MED is a conceptually attractive strategy of minimizing esophageal injury while allowing uninterrupted energy delivery along the posterior left atrium during PV isolation.

METHODS: MED was performed using a malleable metal stylet within a plastic tube placed within the esophagus. Barium was instilled to characterize the trailing esophageal edge. For each MED attempt, the MEDEffective , defined as the distance from the trailing esophageal edge-to-ablation line, was correlated to occurrences of LETElev .

RESULTS: In 114 consecutive patients/221 PV pairs undergoing MED (age 62.1 ± 11 years, 75% men, 62%/38% paroxysmal/persistent AF), esophageal stretching invariably occurred such that the esophageal edge trailed behind the plastic tube. MEDEffective distances of 0 mm to 10 mm, 10 mm to 15 mm, 15 mm to 20 mm or >20 mm were achieved in 60 (27.1%), 64 (29%), 48 (21.7%), and 49 (22.2%) attempts, respectively. Overall, LET elevation >38°C occurred in 81 of 221 (36.7%) PV pairs. The incidence of LETElev among the 4 groups was 73.3%, 35.9%, 25%, and 4.1%, respectively. MEDEffective distances were 9.1 ± 6.5 mm and 18 ± 7.6 mm in patients with and without LETElev , respectively (p < 0.0001). Three patients (2.6%) experienced clinically significant MED-related trauma, albeit only with a stiffer stylet.

CONCLUSIONS: Mechanical esophageal deviation >20 mm from the PV ablation line prevents significant esophageal heating during PV isolation, but this level of displacement was difficult to safely achieve with this off-the-shelf mechanical stylet approach.