LAUSR

Ablation lesions represent a complex interaction between the ablation catheter configuration and tissue anatomy. An understanding of each variable can assist in determination of the optimal lesion set. One such variable is the catheter orientation. With an irrigated radiofrequency ablation catheter with 6 pores (6P) near the distal tip, lesion surface area and volumes are smaller in the horizontal catheter orientation compared to the vertical catheter orientation. This finding is explained by the 6P irrigation catheter design, where irrigation fluid is discharged from six ports around the circumference of the electrode. Introduced in 2015, the ThermoCool SmartTouch® SF catheter has a 56-pore (56P) distribution to provide high density low volume irrigation settings. Irrigation catheters create smaller lesions in horizontal orientation compared to vertical orientation, however this has not been studied for the 56P irrigated catheter. Evaluate the impact of catheter orientation with sequential application of 56P catheter. Ablation lesions were created on additive-free chicken model in a saline bath heated to 37°C using the 56P catheter under standard flow rate (8cc/min) conditions. Ablation energy of 20W and 30W was delivered twice for 30 seconds with 3 minutes interval between applications. Contact force (CF) of 5, 10, 15, and 20g was applied with the following conditions: horizontal catheter orientation followed by horizontal (HH), vertical by vertical (VV), horizontal by vertical (HV), and vertical by horizontal catheter orientation (VH). Measurements were obtained by lesion dissection through the midpoint by 3 independent operators. Kruskal-Wallis test was used for comparison of lesion depth, surface area and volume. Ninety-six lesions were analyzed. No coagulum or steam pops were included in the analysis. The minimum and maximum lesion depth, surface area and volume were 1.5 & 6.0 mm, 14.1 & 117.7mm2, 47.1 & 471.0 mm3 respectively. There was no significant difference in the lesion depth, surface area or volume in HH, VV, HV or VH orientation at different CF with 20W and 30W. (Fig 1) Figure 1 Unlike other irrigated catheters, catheter orientation with sequential application with different CF and power did not impact lesion depth, surface area and volume with 56P catheter. This finding could be considered useful in situations where the catheter orientation could be challenging owing to tissue anatomy to achieve adequate lesion size. UVA Health System