Characteristics and optimal ablation settings of a novel, contact-force sensing and local impedance-enabled catheter in an ex vivo perfused swine ventricle model.

Background Local impedance (LI) has emerged as a new technology that informs on electrical catheter-tissue coupling during radiofrequency (RF) ablation. Recently, IntellaNav StablePoint, a novel LI-enabled catheter that equips contact force (CF) sensing, has been introduced. Although StablePoint and its predecessor IntellaNav MiFi OI share the common technology that reports LI, distinct mechanics for LI sensing between the 2 products raise a concern that the LI-RF lesion formation relationship may differ. Methods In an ex vivo swine cardiac tissue model, we investigated the initial level and range of a reduction in LI during a 60-second RF ablation and the resultant lesion characteristics at 9 combinations of 3 energy power (30, 40, and 50W) and CF (10, 30, and 50g) steps. Correlations and interactions between CF, LI, wattage, and formed lesions were analyzed. Incidence of achieving LI drop plateau and that of a steam pop were also determined. Results Positive correlations existed between CF and initial LI, CF and absolute/relative LI drop, CF and lesion volume, and LI drop and lesion volume. At the same LI drop, wattage-dependent gain in lesion volume was observed. Steam pops occurred in all CF steps and the prevalence was highest at 50W. LI drop predicted a steam pop with a cutoff value at 89Ω. Conclusion In StablePoint, wattage crucially affects LI drop and lesion volume. Because 30W ablation may by underpowered for intramural lesion formation and 50W often resulted in a steam pop, 40W appears to achieve the balance between the safety and efficacy. This article is protected by copyright. All rights reserved.