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

ABSTRACT: 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 < .0001; median, 14.7% vs 8.3%, P < .0001). A receiver?operating characteristic analysis demonstrated that at optimal cutoffs of 12 ohms and 11.6% for the absolute and percentage LI drops, the sensitivity and specificity for predicting the effectiveness of the ablation were 66.5% and 88.2%, and 65.1% and 88.2%, respectively. Finally, bidirectional conduction block along the CTI was achieved in all patients. Conclusions During the LI?guided CTI ablation, the effective RF ablation sites exhibited significantly greater absolute and percentage LI drops than the ineffective RF ablation sites. Absolute and percentage LI drops of 12 ohms and 11.6% may be suitable targets for effective ablation. During the local impedance (LI)?guided linear ablation along the cavo?tricuspid isthmus (CTI), the effective radiofrequency (RF) ablation sites exhibited significantly greater absolute and percentage LI drops than the ineffective RF ablation sites. The receiver operating characteristics analysis suggested that an absolute LI drop of 12 ohms and percentage LI drop of 11.6% may be suitable targets for an effective RF ablation during a CTI linear ablation.

SUBMITTER: Sasaki T 

PROVIDER: S-EPMC7532274 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature