Abstract 2239: The Relationship Between Impedance Change And Catheter Contact Force During Radiofrequency Ablation: Evaluation In A Porcine Ex Vivo Cardiac Model Using A Novel Force-Sensing Irrigated Tip Ablation Catheter
Introduction: Irrigation of the ablation electrode decreases thrombus formation during RF ablation, but the optimal power titration strategy to avoid tissue pops/perforation is unknown. The effect of catheter contact force on the safety and efficacy of irrigated RF ablation of cardiac tissue was examined using a novel externally-irrigated catheter with an integrated contact force sensor (TactiCath, Endosense Inc).
Methods: Freshly-excised hearts from 8 swine were placed in a chamber filled with autologous heparinized blood. Irrigated ablation (17 ml/min) was performed on the LV endocardial surface during superfusion with 3 L/min oxygenated blood (37°C). The coronary arteries were perfused at 125 ml/min. Ablations were performed for 60 sec at 3 contact forces (2, 20 & 60 gm) and 3 power titration strategies –
power titration to achieve an ~15 Ω drop, or fixed power at
Results: Pops were predicted by large impedance falls and high maximal power (Table⇓ & Figure⇓). The impedance change correlated with contact force: 20.6 ± 14.3Ω for 2 gm, 40.7 ± 15.2Ω for 20 gm, and 52 ± 18.6Ω for 60 gm (p<0.001).
Conclusions: In this model of irrigated-tip myocardial tissue ablation, high catheter contact force correlates well with popping phenemona. The impedance fall was also a robust indicator of catheter contact force.