Catheter Ablation -> SVT/AVNRT/WPW/AT: -> Ablation Techniques D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-166 - How Important Is Impedance? Insights On Its Influence On Rf Ablation Lesions And Clinical Rf Application (ID 946)


Background: For RF ablation, power is the mainly considered parameter. However, lesion creation is caused by RF current, resulting from RF power and electric impedance.
Objective: The aim of this study was to analyze the influence of electric impedance on lesion creation and clinical RF application.
Methods: RF current was calculated for different values of RF power and circuit impedance. T
RF ablation lesions were created in a porcine ex-vivo animal model. Lesions volumes were analyzed using a digital precision caliper.
Clinical data of n=100 consecutive RF ablation procedures were collected, which included n=3613 RF applications.
Results: In ablation lesions, RF current showed highest correlation with lesion volumes (R²=0.98), RF power showed significantly less correlation with lesion volumes (R²=0.79), p>0.05. Lesion volumes were significantly different when applied with the same RF power but different electric impedances (p<0.01). The figure shows the relation between RF current, RF power and impedance (A) as well as RF power corrected for 100 Ohm impedance (B). The relation between RF current and RF power in a clinical setting is shown in C). In n=3613 RF applications, mean power was 39±7 W, mean impedance was 124±18 [78 - 214] Ohm, and mean current was 614±78 [105 - 866] mA.
Conclusion: RF lesion creation is rather determined by RF current than by RF power. In a clinical setting, electric impedance has a significant influence on RF current delivery and shows a large variation between patients. 20W/80Ohm, 30W/120Ohm, 40W/160 Ohm, 50W/200Ohm ablations result in the same RF current (500mA) and lesions. Thus, impedance should become a well-considered parameter in clinical RF application.