Catheter contact angle influences local impedance drop during radiofrequency catheter ablation: Insight from a porcine experimental study with 2 different LI-sensing catheters

Background Local impedance (LI) can indirectly measure catheter contact and tissue temperature during radiofrequency catheter ablation (RFCA). However, data on the effects of catheter contact angle on LI parameters are scarce. This study aimed to evaluate the influence of catheter contact angle on LI changes and lesion size with two different LI-sensing catheters in a porcine experimental study. Methods Lesions were created by the INTELLANAV MiFi (TM) OI (MiFi) and the INTELLANAV STABLEPOINT (TM) (STABLEPOINT). RFCA was performed with 30 W and a duration of 30 s. The contact force (CF) (0, 5, 10, 20, and 30 g) and catheter contact angle (30 degrees, 45 degrees, and 90 degrees) were changed in each set (n = 8 each). The LI rise, LI drop, and lesion size were evaluated. Results The LI rise increased as CF increased. There was no angular dependence with the LI rise under all CFs in the MiFi. On the other hand, the LI rise at 90 degrees was lower than at 30 degrees under 5 and 10 g of CF in STABLEPOINT. The LI drop increased as CF increased. Regarding the difference in catheter contact angles, the LI drop at 90 degrees was lower than that at 30 degrees for both catheters. The maximum lesion widths and surface widths were smaller at 90 degrees than at 30 degrees, whereas there were no differences in lesion depths. Conclusion The LI drop and lesion widths at 90 degrees were significantly smaller than those at 30 degrees, although the lesion depths were not different among the 3 angles for the MiFi and STABLEPOINT.