Lesion Size and Safety Comparison Between the Novel Flex Tip on the FlexAbility Ablation Catheter and the Solid Tips on the ThermoCool and ThermoCool SF Ablation Catheters

Abstract

The FlexAbility™ tip is safe and effective with no significant difference in lesion sizes compared to both standard ThermoCool and ThermoCool SF. FlexAbility™ has a significantly lower risk of steam pops compared to ThermoCool SF in a beating heart as defined predominantly by an abrupt rise of impedance.

Computational Model for Prediction the Occurrence of Steam Pops during Irrigated Radiofrequency Catheter Ablation

“…This is in agreement with a previous experimental report of Nakagawa [9], comparing the incidence of steam pops with the 12-and 56-holes electrode using power settings from 30 to 50 W. Steam pops occurred at power settings higher than 30 W, except for the case of electrode in perpendicular position (no pops occurred up to 35 W). These results support the findings of a recent experimental study [8], where steam pops are obtained for powers from 35 W on, for both 6-holes and 56-holes electrode, but where 30 W was not tested power (only 20, 35 and 50 W) and where the electrode position on the tissue is not reported.…”

“…The feasibility of the model was firstly assessed against previous experimental studies [2,8] using a 6-holes electrode in perpendicular position with respect to the tissue as in the existing experiments for steam pop occurrence [2]. We obtained similar results to the existing experimental ones [2,8]: 1) the calculated rate of volumetric temperature change was always larger than 1.5ºC/s when a steam pop occurred in the tissue, 2) the ablation time, stopped after the pop occurrence, was ≈30 s for a power of 35 W, and 3) the maximum temperature at the catheter tip registered with the model reproduced the experimentally measured for each power setting.…”

“…In the experiments, steam pops occurred at 29.2 ± 15.7 s for a power delivered of 32.7 ± 8.8 W. The model is in close agreement with the experiments, since we obtained steam pops for powers ≥35 W, specifically with power pops at 28 s. As in the experiments, the volumetric temperature of the tissue change was higher than 1.5ºC/s when pops occurred at the tissue, specifically we obtained 1.9, 3.1 and 5.5 ºC/s with 35, 40 and 50 W at the instant of pop occurrence. We also measured the maximum temperature at the catheter tip and we obtained similar temperatures as in the experiments for the 6-holes electrode [8]. In particular, the maximum temperature at the electrode tip in the model was 38.9, 40.4 and 41ºC for 20, 35 and 50 W, whereas in the experiments was 37 ± 3, 40 ± 4 and 42 ± 3ºC for the same powers settings.…”

“…We first assessed the accuracy of the computational model by comparing the computational results with available data from experiments [2,8]. These simulations were conducted using the same conditions as in the experiments [2]: 6-holes electrode in perpendicular position over the tissue, saline irrigation flow rate of 30 mL/min, power settings from 20 to 50 W and ablation time determined by the occurrence of a steam pop.…”

Impact of number of co-existing rotors and inter-electrode distance on accuracy of rotor localization

“…6) is just under the size of the ablation lesion. For example, the diameter of an open-irrigated radiofrequency ablation lesion ranges from 6.1–8.0 mm (35 W × 30 s) to 6.9–8.7 mm (35 W × 60 s) [41,42]. However, the error using the Shannon entropy method (11.8 mm, Fig.…”