Background: Thermal injury to the esophagus during cryoablation for pulmonary vein isolation is a concern despite pre- and intraoperative assessment using conventional techniques. Navik 3D (APN Health, Waukesha, WI) is a novel 3D mapping system that can measure cryoballoon orientation and distance from the esophagus, both factors that correlate with esophageal injury. Purpose: This study assessed Navik 3D for cryoballoon localization and tried to assess the factors determining esophageal injury. Methods: Fifty consecutive patients undergoing cryoballoon ablation for pulmonary vein isolation, roof ablation, and posterior wall debulking were studied retrospectively. Results: Navik 3D was able to accurately compute the distance between the cryoballoon and the esophageal temperature probe in all cases, and also determine its orientation. Since the front half of the cryoballoon is the freezing surface, orientation toward (TOW) the esophagus as well as the actual distance were independent factors determining a decrease in esophageal temperature. Orientation TOW was associated with a lower esophageal temperature by 5.88°C (95% CI -7.20, -4.56; p<0.01) and a decrease in distance by 1 mm was associated with an esophageal temperature lowering of 0.05°C (95% CI 0.03, 0.06; p<0.01). Conclusion: Navik 3D allows accurate, real-time assessment of cryoballoon location and orientation in relation to the esophagus during ablation procedures; this may help prevent thermal injury. [ABSTRACT FROM AUTHOR]