부산대학교 도서관

Ablation catheter contact with tissue fundamentally influences ablation efficacy. Tip-to-tissue impedance reflects electrical contact and EnSite Contact System measures this impedance and quantifies electrical contact through an Electrical Coupling Index (ECI). As introduction of saline impacts system impedance, it was of interest to understand if catheters with the same size tip but varying saline flow profiles registered equal ECI values at the same level of contact.A bench study was performed using 6-hole and a 12-hole 4 mm irrigated St. Jude Medical ablation catheters (3 samples of each). In the study, the catheter tip was incrementally lowered (0.1mm per step for 50 steps) into bovine myocardial tissue. At each step, force and ECI were measured. Measurements were collected with the saline irrigation pump set to no flow, 2 ml/min, or 13 ml/min in parallel and in perpendicular orientations (n=180). The change in ECI (ΔECI) from a noncontact location to a contact location with 10 grams of force was calculated and compared.A paired two-tailed t-test revealed that there was no significant difference (p>0.05) between ΔECI measurements collected with the different catheter types at the three saline flow rates (see table below).Results show that statistically equivalent ΔECI measurements are collected with two different 4mm catheter types with varying saline flow rates. Further testing in an in vivo model is warranted to confirm these results as the bench model does not account for blood flow. For this reason, it may represent a worst case scenario for any changes in ECI with saline infusion. (Table is included in full-text article.)