Comparison of lesion characteristics using temperature‐flow‐controlled versus conventional power‐controlled ablation with fixed ablation index

Abstract

Introduction The QDOT‐MicroTM catheter is a novel irrigated contact force (CF) sensing catheter which benefits from thermocouples for temperature monitoring, allowing temperature‐flow‐controlled (TFC) ablation. We compared lesion metrics at fixed ablation index (AI) value during TFC‐ablation and conventional power‐controlled (PC)‐ablation. Methods A total of 480 RF‐applications were performed on ex‐vivo swine myocardium with predefined AI targets (400/550) or until steam‐pop occurred, using the QDOT‐MicroTM (TFC‐ablation) and Thermocool SmartTouch SFTM (PC‐ablation). Results Both TFC‐ablation and PC‐ablation produced similar lesions in volume (218 ± 116 vs. 212 ± 107 mm3, p = .65); however, lesions using TFC‐ablation were larger in surface area (41.3 ± 8.8 vs. 34.8 ± 8.0 mm2, p < .001) and shallower in depth (4.0 ± 1.0 vs. 4.2 ± 1.1 mm, p = .044). Average power tended to be lower in TFC‐alation (34.2 ± 8.6 vs. 36.9 ± 9.2, p = .005) compared to PC‐ablation due to automatic regulation of temperature and irrigation‐flow. Although steam‐pops were less frequent in TFC‐ablation (24% vs. 15%, p = .021), they were particularly observed in low‐CF (10 g) and high‐power ablation (50 W) in both PC‐ablation (n = 24/240, 10.0%) and TFC‐ablation (n = 23/240, 9.6%). Multivariate analysis revealed that high‐power, low‐CF, long application time, perpendicular catheter orientation, and PC‐ablation were risk factors for steam‐pops. Furthermore, activation of automatic regulation of temperature and irrigation‐flow was independently associated with high‐CF and long application time while ablation power had no significant relationship. Conclusions With a fixed target AI, TFC‐ablation reduced the risk of steam‐pops, producing similar lesions in volume, but with different metrics in this ex‐vivo study. However, lower CF and higher power in fixed‐AI ablation may increase the risk of steam‐pops.

An optimized approach for increasing lesion size in temperature‐controled setting using a catheter with a surface thermocouple and efficient irrigation

“…As demonstrated in previous clinical studies, 9,10,21,28 the safety and efficacy of HNS irrigation may vary depending on the catheter platform, including factors such as electrode size and material, location and the number of thermocouples, volume, and method of irrigation, and the ablation mode (e.g., power‐controlled vs. temperature control). It is conceivable that the use of HNS‐irrigation may be safer and more effective than increasing the power of duration with one catheter platform, while the opposite may be true for another catheter platform.…”

Impact of contact force on the lesion characteristics of very high‐power short‐duration ablation using a QDOT‐MICRO catheter

“…Leshem et al reported that temperature‐ and irrigation flow‐controlled RF ablation using the QDOT‐MICRO™ catheter produced similar lesion depth with fewer steam‐pops than power‐controlled ablation at 40–50 W settings 15 . vHPSD ablation using a QDOT‐MICRO™ catheter may safely produce more homogenous lesions in both the atrium and ventricle 16 …”

“…15 vHPSD ablation using a QDOT-MICRO™ catheter may safely produce more homogenous lesions in both the atrium and ventricle. 16 The safety of vHPSD ablation using the QDOT-MICRO™ catheter has also been reported in clinical studies. Halbfass et al reported a two-center trial where none of the 90 patients who underwent pulmonary vein isolation (PVI) with vHPSD ablation using QDOT-MICRO™ demonstrated steam-pops, cardiac tamponades, fistulas, esophageal ulcerations, or strokes.…”