Optimal local impedance drops for an effective radiofrequency ablation during cavo-tricuspid isthmus ablation

Abstract

Purpose: A novel ablation catheter capable of local impedance (LI) monitoring (IntellaNav MiFi OI, Boston Scientific) has been recently introduced to clinical practice. We aimed to determine the optimal LI drops for an effective radiofrequency ablation during cavo-tricuspid isthmus (CTI) ablation. Methods: This retrospective observational study enrolled 50 consecutive patients (68 ± 9 years; 34 males) who underwent a CTI ablation using the IntellaNav MiFi OI catheter, guided by Rhythmia. The LI at the start of radiofrequency applications (initial LI) and minimum LI during radiofrequency applications were evaluated. The absolute and percentage LI drops were defined as the difference between the initial and minimum LIs and 100× absolute LI drop/initial LI, respectively. Results: A total of 518 radiofrequency applications were analyzed. The absolute and percentage LI drops were significantly greater at effective ablation sites than ineffective sites (median, 15 ohms vs 8 ohms, P