Abstract 15821: Demonstration of the Anatomical Tachycardia Circuit in Sinoatrial Node Reentrant Tachycardia: Analysis Using the Entrainment Method

Background: The anatomical tachycardia circuit in the sinoatrial node reentrant tachycardia (SANRT) is not well clarified. Objective: The purpose of this study was to define the reentry circuit of SANRT using the entrainment method. Methods: In 12 patients with SANRT, the earliest atrial activation site (EAAS) was identified by the three-dimensional mapping system (EnSite). While recording the atrial electrogram at the EAAS during tachycardia, rapid atrial pacing at a rate 5 beats/minute faster than the tachycardia rate was delivered from multiple sites of right atrium (RA) and coronary sinus (CS) to demonstrate manifest entrainment with orthodromic capture of EAAS, and defined the direction of proximity of slow conduction area (SCA) of reentry circuit. When EAAS was orthodromically captured with manifest entrainment, radiofrequency energy was delivered starting at a site 2 cm away from the EAAS in the direction of entrainment pacing site. Then application site was gradually advanced toward EAAS until SAN...