Utility of omnipolar mapping-guided cavotricuspid isthmus block.

Background: Omnipolar mapping is an emerging technology with the potential to identify the critical conduction site in the cavotricuspid isthmus (CTI). Objective: This study aimed to elucidate the efficacy of omnipolar mapping-guided targeted ablation to create a CTI block. Methods: Patients who underwent a CTI block using radiofrequency applications (RFAs) were included. Omnipolar mapping was performed during CTI-dependent atrial flutter or pacing from the coronary sinus with a drive train (S1) and a single extra stimulus (S2), and 2 omnipolar maps were created: one with annotation of local potentials after S1 pacing (S1 map) and the other after S2 pacing (S2 map). RFAs were preferentially attempted at the atrial activation focusing sites (AAFSs) where atrial electrical excitation conducts centripetally toward those sites and centrifugally away from them in the omnipolar map. Results: 50 patients were included. AAFSs were identified in 33 of 38 patients in whom an omnipolar map was created during sustained atrial flutter and in the S2 map in 11 of 12 patients in whom an omnipolar map was created during programmed pacing from the coronary sinus. No AAFS was identified in the S1 map. In the 44 patients in whom AAFSs were identified, a block line in the CTI was completed only by RFAs at the AAFSs, and a continuous linear ablation in the CTI was not necessary. Conclusion: An omnipolar mapping system can identify critical sites for a CTI block by visualizing AAFSs. The AAFSs might be preferable ablation targets in a targeted CTI block.