AUTHOR=Amorós-Figueras Gerard , Moreno-Weidmann Zoraida , Méndez-Zurita Francisco , Soriano-Amores Marc , Bragós Ramon , Rosell-Ferrer Javier , Guerra Jose M. 

TITLE=Local multifrequency impedance changes after radiofrequency ablation in human atria: potential use for tissue characterization

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 12 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2025.1668533

DOI=10.3389/fcvm.2025.1668533

ISSN=2297-055X

ABSTRACT=BackgroundLocal impedance (LI) mapping provides additional tissue characterization of the atria substrate. Measuring LI at different current frequencies has the advantage of exploring intra- and extra-cellular compartments and may add useful information about tissue integrity. The objective of this study was to characterize the changes in local multifrequency impedance (LMI) after radiofrequency ablation in human atrial tissue.MethodsIn fifteen patients undergoing catheter ablation of atrial arrhythmias, we constructed a baseline high-density electroanatomical map (EAM) and measured the LMI (1–1,000 kHz) at fifty sites around the cava veins using the QDOT or Smarttouch electrocatheter. Then a point-by-point pulmonary vein isolation procedure was performed using radiofrequency energy in a temperature controlled mode (90W for 4 s for QDOT/30W for 30 s for Smarttouch). After confirming the PVI fifty additional LMI recordings per patient were performed around the initial sites. We performed an offline analysis to compare the values of bipolar voltage and LMI of blood, pre- and post-ablated tissue. We also analyzed the cardiac cycle changes of LMI and the effects of catheter orientation to the LMI, contact force and bipolar voltage.ResultsA total of 641 pre-ablated and 190 post-ablated sites were studied from all patients. Blood pool, healthy and post-ablated myocardium presented distinctive LMI signatures (ZPRE = 110 ± 15 Ω vs. ZPOST = 90 ± 10 Ω vs. ZBLOOD = 90 ± 8 Ω; p < 0.001). LMI cyclic changes showed an inverse relationship with the contact force, and these were more attenuated in the post-ablated tissue (p < 0.001).ConclusionsLMI can differentiate pre- from post-ablated tissue in a cohort of patients submitted to RF ablations. This new tool could be of potential clinical applicability for the characterization of the atrial substrate and to monitor lesion quality to perform durable ablation lesions.Clinical Trial RegistrationNCT05159180 (https://www.clinicaltrials.gov); Unique Protocol ID: IIBSP-IMS-2021-74.