Intracardiac Ultrasound During Left Atrial Ablation for Atrial Fibrillation. Background: Esophageal injury during left atrial ablation is associated with a significant risk of mortality and morbidity. There are no validated approaches to reduce injury outside of avoidance, a strategy critically dependent on a precise understanding of the esophageal anatomy and location. Intracardiac ultrasound (ICE) can provide a real-time assessment of the esophagus during ablation. We hypothesized that ICE can accurately define esophageal anatomy and location to enhance avoidance strategies during ablation.
Methods: Fifty patients underwent atrial fibrillation (AF) ablation. The left atrium and pulmonary vein anatomies were rendered by traditional electroanatomic mapping (CARTO). A Navistar catheter within the esophagus was used to create a traditional electroanatomic esophageal anatomy. ICE imaging was used to create a second geometry of the esophagus. The traditional and ICE anatomies of the esophagus were compared and the greatest border dimensions used to avoid injury.
Results: The average age was 66 ± 10 years, 45% had persistent/longstanding persistent AF, and 18% had a prior AF ablation. The esophagus location was leftward in 17 (34%), midline in 22 (44%), and rightward in 11 (22%). Traditional esophagus and ICE imaging correlated within 1 cm in the greatest distance in 26 (52%) patients. Traditional imaging underestimated the esophageal location by >1–1.5 cm in 9 (18%) and >1.5 cm in 15 (30%). In those with poor correlation (>1.5 cm), the most common cause was the presence of a hiatal hernia. Ablation energy delivery was performed outside the greatest esophagus anatomy borders. Of those with 12-month follow-up, 75% were AF/atrial flutter free without antiarrhythmic drugs. No esophageal injuries were observed. One patient experienced a TIA greater than 6 months postablation.
Conclusion: These data demonstrate that traditional means of mapping the esophagus using a catheter within the esophagus are insufficient and often grossly underestimate the actual anatomy. Imaging techniques that define the complete esophageal lumen should be considered to truly minimize esophageal injury risk. (J Cardiovasc Electrophysiol, Vol. 24, pp. 33-39, January 2013)