Theoretical and experimental analysis of amplitude control ablation and bipolar ablation in creating linear lesion and discrete lesions for treating atrial fibrillation

Yan, Shengjie; Wang, Xiaomei; Wang, Weiqi

doi:10.1080/02656736.2017.1286390

Cited by 12 publications

(14 citation statements)

References 35 publications

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“…Additionally, adequate spatial and temporal resolution was estimated using similar convergence tests. The difference of maximal temperature in cardiac tissue less than 0.5% between consecutive simulations was used as the control parameter in the convergence tests [20]. The values determined were as follows: X ¼ 260 mm, Y ¼ 130 mm, and time step ¼ 0.02 s. In this study, we used COMSOL Multiphysics 5.3a to build a finite element model and find a solution.…”

Section: Construction Of the Computer Modelmentioning

confidence: 99%

Computer simulation study on the effect of electrode–tissue contact force on thermal lesion size in cardiac radiofrequency ablation

Yan

Wang

et al. 2020

International Journal of Hyperthermia

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Purpose: In cardiac radiofrequency (RF) ablation, RF energy is often used to create a series of transmural lesions for blocking accessory conduction pathways. Electrode-tissue contact force (CF) is one of the key determinants of lesion formation during RF ablation. Low electrode-tissue CF is associated with ineffective RF lesion formation, whereas excessive CF may increase the risk of steam pop and perforation. By using finite element analysis, we studied lesion size and features at different values of electrode-tissue CF in cardiac RF ablation. Materials and methods: A computer-model-coupled electrode-tissue CF field, RF electric field, and thermal field were developed to study temperature distribution and lesion dimensions in cardiac tissue subjected to CF of 2, 5, 10, 20, 30, and 40 g with identical RF voltage and duration. Results: Increasing CF was associated with an increase in lesion depth, width, and cross-section area. The lesion cross-section area exhibited a linear increase, and the lesion width was significantly greater than lesion depth under the identical ablation condition. The relationship between CF value and lesion size is a power function: Lesion Size ¼ a Â CF b (Lesion Depth ¼ 3.17 Â CF 0.14 and Lesion Width ¼ 5.17 Â CF 0.14). Conclusions: This study confirmed that CF is a major determinant of RF lesion size and that electrode-tissue CF affects the amount of power dissipated in tissue. At a constant RF voltage and application time, RF lesion size increases as CF increases.

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Section: Construction Of the Computer Modelmentioning

confidence: 99%

Computer simulation study on the effect of electrode–tissue contact force on thermal lesion size in cardiac radiofrequency ablation

Yan

Wang

et al. 2020

International Journal of Hyperthermia

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“…The values of the electrical and thermal conductivities of the myocardium shown in Table 1 were assessed at an ambient temperature of 37 °C. These two parameters are temperature-dependent and follow unique piecewise relations [19,20]. The electrical conductivity increased exponentially at a rate of 1.5% °C −1 below 100 °C and then dropped by four orders of magnitude between 100 °C and 105 .…”

Section: Materials Properties and Boundary Conditionsmentioning

confidence: 99%

“…The catheter penetrated the myocardium at a depth of 0.1 mm. The thicknesses of blood, myocardium, connective tissue, and muscle were configured to 9 mm, 5 mm [19,20], 2 mm [22], and 18 mm [23], respectively. The thickness of the lung region (Z), length (X), and width (Y) of the entire model were obtained from a convergence test to avoid boundary effects.…”

Section: Construction Of Ablation Modelmentioning

confidence: 99%

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Modeling Analysis of Thermal Lesion Characteristics of Unipolar/Bipolar Ablation Using Circumferential Multipolar Catheter

Wang

Yan

et al. 2020

Applied Sciences

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The circumferential multipolar catheter (CMC) facilitates pulmonary vein isolation (PVI) for the treatment of atrial fibrillation by catheter ablation. However, the ablation characteristics of CMC are not well understood. This study uses the finite element method to conduct a comprehensive analysis of the ablation characteristics of multielectrode unipolar/bipolar (MEU/MEB) modes of the CMC. A three-dimensional computational model of the CMC, including blood, myocardium, connective tissue, lung, and muscle, was constructed. The method was validated by comparing the results of an in vitro experiment with the simulation. Both ablation modes could create contiguous effective lesions, but the MEU mode created a deeper and broader lesion volume than the MEB mode. The MEB mode had an overall higher average temperature field and allowed faster formation of the effective contiguous lesion. The lesion shape tended to be symmetric and spread downward and superficially in the MEU mode and MEB mode, respectively. Results from the simulation for validation agreed with the in vitro experiment. Different ablation trends of the MEU and MEB modes provide different solutions for specific ablation requirements in clinical applications. The MEU mode suits transmural lesion in thick tissue around pulmonary veins (PVs). The MEB mode profits fast and durable creation of circumferential PVI. This study provides a detailed performance analysis of CMC, thereby contributing to the theoretical knowledge base of application of PVI with this emerging technology.

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“…These studies are used to characterize everything from catheter performance [13], temperature distributions, procedural factors influencing lesion formation [14], device quality, lesion geometry, control algorithms [15], [16], different electrode configurations [17] and much more. As expected, there is a lot of inherent variability in this testing procedure due to tissue inhomogeneity and visual assessment; therefore, to produce any statistically meaningful results, the sample size of studies needs to be large.…”

Section: Current Methods Of Ablation Catheter Lesion Evaluationmentioning

confidence: 99%

A 3-Dimensional In Silico Test Bed for Radiofrequency Ablation Catheter Design Evaluation and Optimization

Teng¹

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A 3-Dimensional in Silico Test Bed for Radiofrequency Ablation Catheter Design Evaluation and Optimization Carolyn Teng Atrial fibrillation (AF) is the disordered activation of the atrial myocardium, a major cause of thrombogenesis and stroke. Currently, the most effective minimally traumatic treatment for AF is percutaneous catheter ablation to isolate arrhythmogenic areas from the rest of the atrium. The standard in vitro evaluation of ablation catheters through lesion studies is a resource intensive effort due to ablation substrate tissue variability and visual measurement methods, necessitating large sample sizes and multiple prototype builds. To address this, a computational test bed for ablation catheter evaluation was built in SolidWorks® using morphology and dimensions of the left atrium and adjacent structures. From this geometry, the physical model was built in COMSOL Multiphysics®, where a combination of laminar fluid flow, electrical currents, and bioheat transfer were used to simulate irrigated radiofrequency (RF) tissue ablation. Simulations in simplified 3D geometries led to lesion sizes within reported ranges from an in-vivo ablation study; however, while the ellipsoid morphologies in the full atrial model were consistent with past lesion studies, there were sizeable differences in lesion sizes. Perpendicularly oriented catheter tips were associated with decreases of-91.3% and-70.0% in lesion depth and max diameter, while tangentially oriented catheter tips produced lesions that were off by-28.4% and +7.9% off for max depth and diameter. Preliminary investigation into the causes of the discrepancy were performed for fluid velocity, contact area, and other factors. Guided by the findings of these studies, suggestions for further investigation are provided to aid in root cause determination of this lesion discrepancy, such that the test bed may be verified for use for other ablation catheter evaluations.

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Theoretical and experimental analysis of amplitude control ablation and bipolar ablation in creating linear lesion and discrete lesions for treating atrial fibrillation

Abstract: Amplitude control ablation technology and bipolar ablation technology are feasible methods to create continuous lesion or discrete for pulmonary veins isolation.

Cited by 12 publications

References 35 publications

Computer simulation study on the effect of electrode–tissue contact force on thermal lesion size in cardiac radiofrequency ablation

Computer simulation study on the effect of electrode–tissue contact force on thermal lesion size in cardiac radiofrequency ablation

Modeling Analysis of Thermal Lesion Characteristics of Unipolar/Bipolar Ablation Using Circumferential Multipolar Catheter

A 3-Dimensional In Silico Test Bed for Radiofrequency Ablation Catheter Design Evaluation and Optimization

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