Abstract 12563: Anatomical Situation Surrounding the Esophagus Affects the Prevalence of Transmural Thermal Injury After Pulmonary Vein Isolation

Introduction: Transmural thermal injury (TTI), such as esophageal erythema and periesophageal nerve injury leading to gastric hypomotility, is an important complication associated with pulmonary vein isolation (PVI). Esophagus is surrounded with a small distance by left atrium (LA) posterior wall, descending aorta and left inferior PV (LIPV) in infero-posterior portion of LA. However, the predictor of this complication associated with anatomical situation among these structures has not been fully established. Methods: The consecutive 133 patients (61±9 years, 111 men) who underwent PVI for drug refractory atrial fibrillation and gastrointestinal endoscopy on the day following PVI were investigated. With echocardiography data, LA dimension and LA volume index in each patient were measured. We measured the angle of LA posterior wall to descending aorta (LA-Ao angle), the branching angle of LIPV to coronal plane (LIPV angle), and the minimum distance between descending aorta and LA posterior wall sandwiching esophagus with computed tomography. The relationships of TTI with clinical and anatomical parameters were examined. Results: All patients had left-sided or central location of esophagus, which overlay the posterior ablation line of left PV. Radiofrequency energy was delivered with a maximum output of 20 watts, and contact force was maintained between 10-20 g in left posterior ablation line. TTIs were occurred in 24 patients after PVI (erythema in 5 and gastric hypomotility in 19). The parameters including age, gender, body mass index, LA diameter and LA volume index in echocardiography were not associated with the prevalence of TTI. However, LIPV angle was larger (33.2±13.6 ° vs. 20.7±10.2 °, P< 0.0001) and LA-Ao distance was shorter (4.3±1.4 mm vs. 6.2±2.4 mm, P= 0.0002) in TTI (+) group compared to TTI (-) group. LA-Ao angle tended to be smaller in TTI (+) group (25±10 degrees vs. 29±10 degrees, P= 0.08), and was significantly correlated with LA-Ao distance (R= 0.321, P= 0.0002). Conclusion: The anatomical proximity of LA posterior wall, LIPV and descending aorta surrounding esophagus is strongly associated with the prevalence of TTI.