Relationship between the ablation index, lesion formation, and incidence of steam pops

Mori, Hitoshi; Kato, Ryuichi; Sumitomo, Naokata; Ikeda, Yoshifumi; Goto, Koji; Tanaka, Sayaka; Asano, So; Tahara, Mai; Nagase, Takahiko; Iwanaga, Shiro; Muramatsu, Toshihiro; Matsumoto, Kazuo

doi:10.1002/joa3.12195

Cited by 33 publications

(55 citation statements)

References 18 publications

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“…The results are consistent with those of previous studies. [ 5 , 6 , 8 , 14 ] In addition, we found when the CF was 10 g or greater; a trans-mural lesion might appear on the free wall of the RVOT. If the lesion became a trans-mural lesion, the maximum depth, and volume of the lesion stopped increasing as the CF increased.…”

Section: Discussionmentioning

confidence: 65%

“…The factors that influence lesion size during ablation include the distal diameter of the ablation catheter, local blood flow velocity, irrigation rate of saline, and the CF between the tip of the ablation catheter and myocardial tissue; among these factors, the CF plays the most important role. [ 5 , 6 , 8 , 11 ] However, ablations were performed on the atrial endocardium or epicardium in most previous studies, and ablations were performed on animal skeletal muscle or ventricular muscle in a few in vitro studies. [ 11 – 14 ] So we performed this in vivo experimental study to evaluate the effect of CF on the size of ablation lesions when using CF-sensing catheters to perform an ablation procedure in the RVOT.…”

Section: Discussionmentioning

confidence: 99%

“…Radiofrequency lesions that formed over the myocardium were measured macroscopically with a high-precision digital caliper (Shanghai Minnet Industrial Co., Ltd., Shanghai, China). The maximum depth, maximum diameter, depth at the maximum diameter, and surface diameter were measured and recorded, and the lesion dimensions and lesion volume were determined using a previously reported formula, [ 6 ] as shown in Figure 1 . Sections from the lesions were obtained and fixed in 10% neutral-buffered formalin (Nanchang Yulu Experimental Equipment Co., Ltd., Nanchang, China).…”

Section: Methodsmentioning

confidence: 99%

“…The contact force (CF) between the catheter tip and myocardial tissue has been shown to be one of the major determinants of lesion size in experimental studies and thus has a significant impact on the effectiveness of VAs ablation procedures. [ 5 , 6 ] On the contrary, excessive CF may lead to an increased risk of severe procedural complications, such as cardiac tamponade and steam pops. [ 6 – 8 ] Unfortunately, the range of effective and safe CF values that need to be maintained during ablation in RVOT remains unclear.…”

Section: Introductionmentioning

confidence: 99%

“…[ 5 , 6 ] On the contrary, excessive CF may lead to an increased risk of severe procedural complications, such as cardiac tamponade and steam pops. [ 6 – 8 ] Unfortunately, the range of effective and safe CF values that need to be maintained during ablation in RVOT remains unclear. Our study aimed to evaluate the impact of the catheter-tissue CF on the lesion size during RVOT ablation in an experimental swine model using a novel CF-sensing ablation catheter.…”

Section: Introductionmentioning

confidence: 99%

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Impact of catheter-tissue contact force on lesion size during right ventricular outflow tract ablation in a swine model

Jiang

et al. 2020

Chinese Medical Journal

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Background The catheter-tissue contact force (CF) is one of the significant determinants of lesion size and thus has a considerable impact on the effectiveness of ablation procedures. This study aimed to evaluate the impact of CF on the lesion size during right ventricular outflow tract (RVOT) ablation in a swine model. Methods Twelve Guangxi Bama miniature male pigs weighing 40 to 50 kg were studied. After general anesthesia, a ThermoCool SmartTouch contact-sensing ablation catheter was introduced to the RVOT via the femoral vein under the guidance of the CARTO 3 system. The local ventricular voltage amplitude and impedance were measured using different CF levels. We randomly divided the animals into the following four groups according to the different CF levels: group A (3–9 g); group B (10–19 g); group C (20–29 g); and group D (30–39 g). Radiofrequency ablations were performed at three points in the free wall and septum of the RVOT in power control mode at 30 W for 30 s while maintaining the saline irrigation rate at 17 mL/min. At the end of the procedures, the maximum depth, surface diameter, and lesion volume were measured and recorded. A linear regression analysis was performed to determine the relationship between continuous variables. Results A total of 72 ablation lesions were created in the RVOT of the 12 Bama pigs. The maximum depth, surface diameter, and volume of the lesions measured were well correlated with the CF (free wall: β = 0.105, β = 0.162, β = 3.355, respectively, P < 0.001; septum: β = 0.093, β = 0.150, β = 3.712, respectively, P < 0.001). The regional ventricular bipolar voltage amplitude, unipolar voltage amplitude, and impedance were weakly positively associated with the CF ( β = 0.065, β = 0.125, and β = 1.054, respectively, P < 0.001). There was a significant difference in the incidence of steam pops among groups A, B, C, and D (free wall: F = 7.3, P = 0.032; septum: F = 10.5, P = 0.009); and steam pops occurred only when the CF exceeded 20 g. Trans-mural lesions were observed when the CF exceeded 10 g in the free wall, while the lesions in the septum were non-trans-mural even though the CF reached 30 g. Conclusions CF seems to be a leading predictive factor for the size of formed lesions in RVOT ablation. Maintaining the CF value between 3 and 10 g may be reasonable and effective for creating the necessary lesion size and reducing the risk of complications, such as steam pops and perforations.

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Section: Discussionmentioning

confidence: 65%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of catheter-tissue contact force on lesion size during right ventricular outflow tract ablation in a swine model

Jiang

et al. 2020

Chinese Medical Journal

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Real‐Time Internal Steam Pop Detection during Radiofrequency Ablation with a Radiofrequency Ablation Needle Integrated with a Temperature and Pressure Sensor: Preclinical and Clinical Pilot Tests

Park

Jeong

et al. 2021

Advanced Science

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A radiofrequency ablation (RFA) needle integrated with a temperature sensor (T-sensor) and pressure sensor (P-sensor) is designed and utilized for real-time internal steam pop monitoring during RFA. The characteristics of the sensor-integrated RFA needle (sRFA-needle) are investigated quantitatively using a pressure chamber system, and the feasibility and usability of the needle in preclinical and clinical trials is demonstrated. The sharp changes in the temperature and normalized pressure sensor signals induced by the abrupt release of hot and high-pressure steam can be clearly monitored during the steam pop phenomena. The basic mechanism of the preliminary steam pop is hypothesized and verified using in situ ultrasound imaging data and computational analysis data of the RFA procedure. Moreover, the usability of the system in clinical trials is investigated, and the steam pop phenomena during the RFA procedure are detected using T-sensor and P-sensor. The results confirm that the sensor integration on the medical needle can provide critical data for safer and more effective medical practices.

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Time dependency in the radiofrequency lesion formation for a local impedance guided catheter in an ex vivo experimental model

Kawano

Mori

Tsutsui

et al. 2022

Journal of Arrhythmia

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Background The local impedance (LI) is an emerging technology that monitors tissue‐catheter coupling during radiofrequency (RF) ablation. The relationships between the LI, RF delivery time, and lesion formation remain unclear. Methods Using an LI‐enabled RF catheter in an ex vivo experimental model, RF lesions were created combined with various steps in the power (40 and 50 W), CF (10 g, 30 g, and 50 g), and time (10s, 20s, 30s, 40s, 50s, and 60s at 40 W and 5 s, 10s, 20s, 30s, 40s, 50s, and 60s at 50 W). The correlations between the LI drop, lesion size, and RF delivery time were evaluated. The rate of change in the time‐dependent gain in the LI, depth, and diameter and the time to reach 90% decay of the peak dY/dT (time to 90% decay) were assessed. Results The correlation between the LI drop and ablation time revealed non‐linear changes. The time to a 90% decay in the LI drop differed depending on the RF ablation setting and was always shorter with the 50 W setting than 40 W setting. The LI drop always correlated with the lesion formation under all ablation power settings. Deeper or wider lesions were predominantly created within the time to 90% decay of the LI drop. Conclusion The LI drop was useful for predicting lesion sizes. Deeper or wider lesions cannot be obtained with a longer ablation than the 90% decay time of the LI drop. A shorter ablation than the 90% decay time of the LI drop would be preferable for an effective ablation.

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Relationship between the ablation index, lesion formation, and incidence of steam pops

Cited by 33 publications

References 18 publications

Impact of catheter-tissue contact force on lesion size during right ventricular outflow tract ablation in a swine model

Impact of catheter-tissue contact force on lesion size during right ventricular outflow tract ablation in a swine model

Real‐Time Internal Steam Pop Detection during Radiofrequency Ablation with a Radiofrequency Ablation Needle Integrated with a Temperature and Pressure Sensor: Preclinical and Clinical Pilot Tests

Time dependency in the radiofrequency lesion formation for a local impedance guided catheter in an ex vivo experimental model

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