Relationship Between Ablation Lesion Size Estimated by Ablation Index and Different Ablation Settings—an Ex Vivo Porcine Heart Study

Huang, Shu-Tao; Dong, Jianzeng; Wu, Jiahui; Yu, Rong‐Hui; Ning, Man; Sang, Caihua; Jiang, Chen‐Xi; Bai, Rong; Wen, Shaojun; Liu, Nian; Li, Songnan; Wang, Wei; Guo, Xueyuan; Chen, Xuan; Cui, Yi‐Kai; Tang, Ri‐Bo; Ma, Changsheng

doi:10.1007/s12265-020-10037-0

Cited by 10 publications

(11 citation statements)

References 9 publications

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“…In the experiments, the 8 levels of contact force within the clinically used range (2,4,6,10,15,20,30, and 40 gf) were applied to the heart tissue surface in line with the typical clinical contact force ranges [14][15][16]. Using this process, the RF catheter ablation test was repeated 6 times each for the 5 contact angles and 8 contact forces to ensure equal distribution of contact force.…”

Section: Ablation Parametersmentioning

confidence: 99%

“…Conventionally, ablation lesion dimensions are measured using a digital vernier caliper and the lesion area and lesion volume are calculated under the assumption that the ablation lesion is a perfectly symmetrical shape [18][19][20]. However, in reality, the ablation lesion morphology is never perfectly symmetrical.…”

Section: Evaluation Of Ablation Lesion Dimensions and Comparison Of Catheter Contact Area With Ablation Lesion Areamentioning

confidence: 99%

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Catheter contact area strongly correlates with lesion area in radiofrequency cardiac ablation: an ex vivo porcine heart study

Masnok

Watanabe

2021

J Interv Card Electrophysiol

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Purpose Our previous study confirmed that not only force but also the catheter contact angle substantially impacted the contact area and its morphology. Therefore, in this study, we aimed to further investigate the relationship between the catheter contact area and the dimensions of the ablation lesion area as a function of catheter contact angle and force in radiofrequency catheter ablation. Methods The radiofrequency catheter ablation test was performed for 5 contact angles and 8 contact forces at a fixed ablation time of 30 s. The initial impedance was 92.5 ± 2.5 Ω, the temperature during ablation was 30 °C, and the power was 30 W. The irrigation rate during ablation was set to 17 mL/min. Each experiment was repeated 6 times. Results The catheter contact area showed a strong correlation with the ablation lesion area (r = 0.8507). When the contact area was increased, the lesion area also increased linearly in a monotonic manner. The relationships between catheter contact force and ablation lesion area and between catheter contact force and ablation lesion depth are logarithmic functions in which increased contact force was associated with increased lesion area and depth. The catheter contact angle is also an important determinant of the lesion area. The lesion area progressively increased when the contact angle was decreased. In contrast, the lesion depth progressively increased when the contact angle was increased. Conclusions The catheter contact area was strongly correlated with the ablation lesion area. Additionally, catheter contact force and contact angle significantly impacted the dimensions of the lesion in radiofrequency catheter ablation procedures.

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Section: Ablation Parametersmentioning

confidence: 99%

Section: Evaluation Of Ablation Lesion Dimensions and Comparison Of Catheter Contact Area With Ablation Lesion Areamentioning

confidence: 99%

Catheter contact area strongly correlates with lesion area in radiofrequency cardiac ablation: an ex vivo porcine heart study

Masnok

Watanabe

2021

J Interv Card Electrophysiol

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“…4 In a recently published multicenter study, AI-guided RFCA of PVCs was demonstrated to be effective and safe with shorter procedure time and higher freedom recurrence of clinical VAs in comparison to a group of propensity-matched controls who underwent non-AI guided RFCA. 5 While AI has been tested as a lesion quality marker under different parameters in in vitro experiments, 6,7 there are no preclinical studies thus far that have directly compared an AI-guided strategy to a conventional time-guided ablation approach under similar experimental conditions or validated the comparative reliability of AI dosing with RFCA using lower osmolality irrigation, which has been demonstrated to deliver deeper and larger ventricular lesions. Given the potential application of AI as a lesion quality marker for RFCA of VAs, we sought to comparatively examine lesion characteristics and safety of AI-guided and time-guided approaches for RFCA in a porcine left ventricular (LV) ex vivo model.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, AI-guided procedures were associated with shorter RF delivery time than matched control procedures 5. While several other in vitro studies have examined the utility of AI targets for predicting lesion size in ventricular animal models F I G U R E 3 Interdependency analysis between ablation index (AI) and ablation time using normal saline (NS) irrigation using different ablation parameters settings,6,7,11 the reliability of AI-guided approach has not been directly assessed versus a non-AI guided approach for RFCA. Given its potential clinical role, we conducted in vitro experiments to comparatively test AI-guided (stratified AI targets between 350 and 750) and non-AI guided protocols (prespecified time durations of RF delivery: 10-90 s) in an ex vivo LV model.…”

mentioning

confidence: 99%

Comparison of ablation index versus time‐guided radiofrequency energy dosing using normal and half‐normal saline irrigation in a porcine left ventricular model

Larsen

Du-Fay-de-Lavallaz²,

Winterfield

et al. 2022

Cardiovasc electrophysiol

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Background Ablation Index (AI) is a multiparametric quality marker to assess the durability of radiofrequency (RF) lesions. The comparative effectiveness and safety of AI versus time‐based energy dosing for ablation of ventricular arrhythmias are unknown. Objective We compared AI and time‐based RF dosing strategies in the left ventricles (LVs) of freshly harvested porcine hearts. Methods Ablation was performed in vitro with an open‐irrigated ablation catheter (Thermocool ST/SF), 40 W, contact force 10–15 g. Tissue samples were stained in triphenyltetrazolium chloride for the measurement of lesion dimensions. Results A total of 560 lesions were performed (AI‐group: [n = 360]; time‐group: [n = 200]). Using normal saline (NS) (n = 280), growth in lesion depth slowed after 30 s and AI > 550 in comparison to width, volume, and magnitude of impedance drops which continued to increase with longer RF duration. Risk of steam pop (SP) was higher for RF > 30 s (RF < 30 s:1 SP [2.5%] vs. RF > 30 s: 15 SP [25%]; p = .002) or AI targets >550 (AI: 350–550: 2 SP [2%] vs. AI 600–750: 15 SP [19%]; p = .001). Using half‐normal saline (HNS) (n = 280), lesion dimension and impedance drops were larger and growth in lesion depth slowed earlier (AI: 500). Risk of SPs was higher above AI 550 (AI: 350–550: 7 [7%] SPs vs. AI 600–750: 28 [35%] SPs; p < .00001). While codependent variables, correlation between AI and time was modest‐to‐strong but decreased with longer RF duration. Conclusion In this ex vivo study, AI was a better predictor of lesion dimensions than ablation time and magnitude of impedance drop in the LV using NS and HNS irrigation. AI targets above 550 led to a higher risk of SPs. Future trials are required to verify these findings.

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“…Each diameter was measured three times. The lesion volume was calculated ( 10 ) as follows: volume = [1.33 × π × d × ( a /2) × ( c /2)]/2. All the lesion measurements were collected independently by an investigator who was blinded to the ablation parameters ( Figure 2 ).…”

Section: Methodsmentioning

confidence: 99%

Effect of Baseline Impedance in Radiofrequency Delivery on Lesion Characteristics and the Relationship Between Impedance and Steam Pops

Guo

Sun

et al. 2022

Front. Cardiovasc. Med.

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ObjectiveTo explore the effects of baseline impedance (R) and power (P) on radiofrequency ablation (RFA) lesion characteristics and their correlation with steam pops using ThermoCool SmartTouch-SF (STSF) catheters in the porcine heart.MethodA porcine left ventricle was submerged in 37°C saline ex vivo, and the experiment was performed with various P (P = 30, 40, 50, and 60 W) and multiple R loads (R = 80–100, 100–140, 140–180, and 180–220 Ω) to reach the target ablation index (AI; AI = 350, 450, and 500) or reach the target ablation time using a fixed contact force (CF; CF = 10–15 g) and the same saline irrigation (30 W/8 ml/min or 40–60 W/15 ml/min), repeated five times under each condition.ResultsThe surface diameter, maximum diameter, depth, and volume of the lesions were strongly correlated with the AI (P = 40 W, R = 100–140 Ω, CF = 10–15 g) (r = 0.5412; r = 0.7889; r = 0.9366; and r = 0.913, respectively; all p < 0.05). As the value of R increased, the maximum diameter, depth, and volume of the lesions significantly increased (AI = 350, P = 30 W). Moreover, the higher the baseline value of R, the greater the absolute value of the R decrease (r = 0.9035, p < 0.05, Y = 0.2759 × X – 18.33). Under high power and high impedance, the occurrence rate of steam pops was high (P = 60 W, R = 180–220 Ω, AI when a steam pop occurred: 480 ± 26.5, ablation time: 11.29 ± 1.04 s).ConclusionRadiofrequency catheter ablation (RFCA) in power-controlled mode resulted in various lesion characteristics that were related to diverse baseline Rs. In addition, the incidence of steam pops was strongly correlated with high baseline R and high P.

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Relationship Between Ablation Lesion Size Estimated by Ablation Index and Different Ablation Settings—an Ex Vivo Porcine Heart Study

Cited by 10 publications

References 9 publications

Catheter contact area strongly correlates with lesion area in radiofrequency cardiac ablation: an ex vivo porcine heart study

Catheter contact area strongly correlates with lesion area in radiofrequency cardiac ablation: an ex vivo porcine heart study

Comparison of ablation index versus time‐guided radiofrequency energy dosing using normal and half‐normal saline irrigation in a porcine left ventricular model

Effect of Baseline Impedance in Radiofrequency Delivery on Lesion Characteristics and the Relationship Between Impedance and Steam Pops

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