2.3. Merge the Voltage Map and the Enhanced Cardiac CT

In order to clarify the cause of LAAW scar formation, we merged the 3D electroanatomic voltage maps and enhanced cardiac CT images to observe the anatomical relationship between LAAW scar and aorta and pulmonary artery, respectively, for 7 patients. One patient's mapping data of tachycardia was lost. The anatomical distance between the LA and those structures was measured, and any anterior external structures of <3 mm in distance from the LA anterior wall were defined as having contact. Subsequently, we traced the contact areas inside the LA on each 2-3 mm CT slice, and 4 areas were created on the 3D maps.