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Xing X, Song C. A novel electrode for reducing tissue thermal damage in radiofrequency-induced intestinal anastomosis. MINIM INVASIV THER 2024; 33:80-89. [PMID: 38147884 DOI: 10.1080/13645706.2023.2297774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 11/28/2023] [Indexed: 12/28/2023]
Abstract
PURPOSE This study aimed to design a novel electrode for reducing tissue thermal damage in radiofrequency-induced intestinal anastomosis. MATERIAL AND METHODS We developed and compared two electrodes (Ring electrode, and Plum electrode with reduced section of the middle fusion area by nearly 80% arising from novel structural design) by performing ex-vivo experiments and finite element analysis. RESULTS In contrast to the Ring electrode group, slightly higher mean strength is acquired with the tensile force and burst pressure results increasing from 9.7 ± 1.47 N, 84.0 ± 5.99 mmHg to 11.1 ± 1.71 N, 89.4 ± 6.60 mmHg, respectively, as well as a significant reduction in tissue thermal damage for the Plum electrode group, with compression pressure of 20 kPa, RF energy of 120 W and welding duration of 8 s applied to the target regions to achieve anastomosis. Besides, the novel structural design of the Plum electrode can counteract the tension generated by intestinal peristalsis and enhance the biomechanical strength of the anastomotic area. The histological observation showed that the fusion area of the two-layer intestinal tissue is tightly connected with decreased thickness. CONCLUSION The novel electrode (Plum electrode) could reduce tissue thermal damage in radiofrequency-induced intestinal anastomosis.
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Affiliation(s)
- Xupo Xing
- Shanghai Institute for Minimally Invasive Therapy, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Chengli Song
- Shanghai Institute for Minimally Invasive Therapy, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
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Tu L, Zhou YU, Wang P, Wang H, Mao LIN, Hou J, Liu Z, Song C. Minimizing thermal damage using self-cooling jaws for radiofrequency intestinal tissue fusion. MINIM INVASIV THER 2023; 32:33-41. [PMID: 36519801 DOI: 10.1080/13645706.2022.2155064] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Radiofrequency (RF)-induced tissue fusion shows great potential in sealing intestinal tissue without foreign materials. To improve the performance of RF-induced tissue fusion, a novel self-cooling jaw has been designed to minimize thermal damage during the fusion. MATERIAL AND METHODS The prototype of self-cooling jaws was developed and manufactured. A total number of 60 mucosa-to-mucosa fusions were conducted using ex-vivo porcine intestinal segments with the proposed design and conventional bipolar jaws. The effects of intestinal fusion were evaluated based on temperature curves, burst pressure, thermal damage, and histological appearances. RESULTS The self-cooling jaws showed significant decrease in temperature during the fusion process. An optimal burst pressure (5.7 ± 0.5 kPa) and thermal damage range (0.9 ± 0.1 mm) were observed when the applied RF power was 100 W. The thermal damage range of the prototype has almost decreased 36% in comparison with the conventional bipolar jaws (1.4 ± 0.1 mm). The histological observation revealed that a decrease of thermal damage was achieved through the application of self-cooling jaws. CONCLUSIONS The self-cooling jaws were proved to be effective for reducing the thermal damage during RF-induced tissue fusion, which could potentially promote the clinical application of tissue fusion techniques in the future.
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Affiliation(s)
- Liangyong Tu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Y U Zhou
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Peiyao Wang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Haochen Wang
- School of Mechanical Engineering, Suzhou University of Science and Technology, Suzhou, China
| | - L I N Mao
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Jian Hou
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Ziyue Liu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Chengli Song
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
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Gómez-Barea M, García-Sánchez T, Ivorra A. A computational comparison of radiofrequency and pulsed field ablation in terms of lesion morphology in the cardiac chamber. Sci Rep 2022; 12:16144. [PMID: 36167959 PMCID: PMC9515184 DOI: 10.1038/s41598-022-20212-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 09/09/2022] [Indexed: 11/15/2022] Open
Abstract
Pulsed Field Ablation (PFA) has been developed over the last years as a novel electrical ablation technique for treating cardiac arrhythmias. It is based on irreversible electroporation which is a non-thermal phenomenon innocuous to the extracellular matrix and, because of that, PFA is considered to be safer than the reference technique, Radiofrequency Ablation (RFA). However, possible differences in lesion morphology between both techniques have been poorly studied. Simulations including electric, thermal and fluid physics were performed in a simplified model of the cardiac chamber which, in essence, consisted of a slab of myocardium with blood in motion on the top. Monopolar and bipolar catheter configurations were studied. Different blood velocities and catheter orientations were assayed. RFA was simulated assuming a conventional temperature-controlled approach. The PFA treatment was assumed to consist in a sequence of 20 biphasic bursts (100 µs duration). Simulations indicate that, for equivalent lesion depths, PFA lesions are wider, larger and more symmetrical than RFA lesions for both catheter configurations. RFA lesions display a great dependence on blood velocity while PFA lesions dependence is negligible on it. For the monopolar configuration, catheter angle with respect to the cardiac surface impacted both ablation techniques but in opposite sense. The orientation of the catheter with respect to blood flow direction only affected RFA lesions. In this study, substantial morphological differences between RFA and PFA lesions were predicted numerically. Negligible dependence of PFA on blood flow velocity and direction is a potential important advantage of this technique over RFA.
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Affiliation(s)
- Mario Gómez-Barea
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain.
| | - Tomás García-Sánchez
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
| | - Antoni Ivorra
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
- Serra Húnter Fellow Programme, Universitat Pompeu Fabra, 08018, Barcelona, Spain
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Gu K, Yan S, Wu X. Influence of pulsating intracardiac blood flow on radiofrequency catheter ablation outcomes in an anatomy-based atrium model. Int J Hyperthermia 2022; 39:1064-1077. [PMID: 35993225 DOI: 10.1080/02656736.2022.2108149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
Abstract
BACKGROUND Highly consistent cardiac ablation outcomes through radiofrequency catheter ablation (RFCA) under pulsatile and constant flow profiles (PP&CP) of intracardiac blood were previously indicated by computer modeling, with simplified geometry and lossless receipt of inflow for ablation catheters. This study aimed to further investigate the effects of intracardiac blood pulsatility in an anatomy-based atrium model. METHODS Four pulmonary veins were blood inflows at 10 mm Hg. The mitral valve was the outflow, with PP based on pulsatile velocity curve from clinical measurements, and CP was obtained by averaging the velocity curve under PP over an ablation time of 30 s. A numerical comparison between ablation results under PP and CP, without experimental validation, was performed. RESULTS Temperature fluctuations persisted in mid-myocardium, and most clearly in blood and endocardium under PP. At a constant power of 20 W, marked differences in ablation outcome between PP and CP occurred in the middle of unilateral pulmonary veins and the posterior wall of the left atrium (LA) where the blood velocities were significantly decreased under CP. The mid-myocardial, blood and endocardial temperatures, as well as the effective lesion volume at the former position, were decreased by 4.1%, 15%, 13.6%, and 13.8%, respectively under PP. The extents for the latter position were 11%, 22%, 22.5%, and 55.6%, respectively. CONCLUSION Intracardiac flow pulsatility causes a greater reduction in blood and endocardial temperatures at ablation sites away from the main bloodstream, effective cooling of which is more likely to rely on blood velocities approaching peak PP values.
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Affiliation(s)
- Kaihao Gu
- Centre for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China
| | - Shengjie Yan
- Centre for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China
| | - Xiaomei Wu
- Centre for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China.,Academy for Engineering and Technology, Fudan University, Shanghai, China.,Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Fudan University, Shanghai, China.,Shanghai Engineering Research Centre of Assistive Devices, Shanghai, China.,Yiwu Research Institute of Fudan University, Yiwu, China
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González-Suárez A, Pérez JJ, Irastorza RM, D'Avila A, Berjano E. Computer modeling of radiofrequency cardiac ablation: 30 years of bioengineering research. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 214:106546. [PMID: 34844766 DOI: 10.1016/j.cmpb.2021.106546] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/08/2021] [Accepted: 11/15/2021] [Indexed: 06/13/2023]
Abstract
This review begins with a rationale of the importance of theoretical, mathematical and computational models for radiofrequency (RF) catheter ablation (RFCA). We then describe the historical context in which each model was developed, its contribution to the knowledge of the physics of RFCA and its implications for clinical practice. Next, we review the computer modeling studies intended to improve our knowledge of the biophysics of RFCA and those intended to explore new technologies. We describe the most important technical details of the implementation of mathematical models, including governing equations, tissue properties, boundary conditions, etc. We discuss the utility of lumped element models, which despite their simplicity are widely used by clinical researchers to provide a physical explanation of how RF power is absorbed in different tissues. Computer model verification and validation are also discussed in the context of RFCA. The article ends with a section on the current limitations, i.e. aspects not yet included in state-of-the-art RFCA computer modeling and on future work aimed at covering the current gaps.
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Affiliation(s)
- Ana González-Suárez
- Electrical and Electronic Engineering, National University of Ireland Galway, Ireland; Translational Medical Device Lab, National University of Ireland Galway, Ireland
| | - Juan J Pérez
- Department of Electronic Engineering, BioMIT, Universitat Politècnica de València, Valencia, Spain
| | - Ramiro M Irastorza
- Instituto de Física de Líquidos y Sistemas Biológicos (CONICET), La Plata, Argentina; Instituto de Ingeniería y Agronomía, Universidad Nacional Arturo Jauretche, Florencio Varela, Argentina
| | - Andre D'Avila
- Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Enrique Berjano
- Department of Electronic Engineering, BioMIT, Universitat Politècnica de València, Valencia, Spain.
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Gu K, Yan S, Wu X. Effect of anisotropy in myocardial electrical conductivity on lesion characteristics during radiofrequency cardiac ablation: a numerical study. Int J Hyperthermia 2022; 39:120-133. [PMID: 35000495 DOI: 10.1080/02656736.2021.2022220] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
BACKGROUND Traditional computer simulation studies of radiofrequency catheter ablation (RFCA) usually neglect the anisotropy in myocardial electrical conductivity (MEC), which is likely an essential factor in governing the ablation outcome. Here, a numerical study of lesion characteristics during RFCA based on an anatomy-based model incorporating fiber orientation was performed to investigate the anisotropy in MEC. METHODS A three-dimensional thorax model including atria, blood, connective tissue, muscle, fat, and skin was constructed. The myocardial fiber was established through a rule-based method (RBM) based on the anatomical structure of the heart. The anisotropic MEC were 0.40 and 0.28 S m-1 in longitudinal and transverse directions, respectively. The ablation result was compared with the isotropic scenario where the isotropic MEC was the average of the anisotropic conductivities as 0.34 S m-1. RESULTS The complexity of fiber architecture varied with that of the local anatomical structure. At RF power of 20 W for 30 s, the tissue temperature and lesion volume were reduced by 2.8 ± 0.1% and 6.9 ± 0.5%, respectively, under anisotropic MEC around the ostium of the pulmonary vein and left atrial appendage. Those for the posterior wall and roof of the left atrium, and the inside of the superior vena cava were 1.9 ± 0.3% and 5.6 ± 1.2%, respectively. CONCLUSIONS Anisotropy in MEC has a greater reduction effect on lesion volume than on tissue temperature during RFCA; this effect tends to be restrained at positions with more uniform fiber distributions and can be enhanced where significant variation in fiber architecture occurred.
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Affiliation(s)
- Kaihao Gu
- Centre for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China
| | - Shengjie Yan
- Centre for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China
| | - Xiaomei Wu
- Centre for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China.,Academy for Engineering and Technology, Fudan University, Shanghai, China.,Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Fudan University, Shanghai, China.,Shanghai Engineering Research Centre of Assistive Devices, Shanghai, China.,Yiwu Research Institute, Fudan University, Yiwu, China
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The AF-FICIENT magnetic resonance imaging and endoscopy safety substudy: A visually guided radiofrequency balloon ablation catheter for pulmonary vein isolation. Heart Rhythm O2 2021; 3:15-22. [PMID: 35243431 PMCID: PMC8859808 DOI: 10.1016/j.hroo.2021.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background Early experience with a novel multielectrode saline-irrigated radiofrequency balloon (RFB) catheter with an integrated camera system found that it was safe and effective in performing single-shot pulmonary vein isolation (PVI) for atrial fibrillation. Objective The purpose of this study was to further assess potential treatment risks by looking for subclinical events. Methods The study was performed at 2 sites. Patients underwent PVI by RFB. A control group underwent conventional point-by-point radiofrequency ablation. Stroke scale questionnaire and brain magnetic resonance imaging (MRI) were performed before and after the ablation procedure, and esophageal endoscopy was performed after the procedure in RFB patients only. Results We enrolled 27 patients in the RFB group and 15 patients in the control group. The RFB and control groups were well matched [predominantly male: 62% vs 53%; CHA2DS2-VASc score: 1.9 ± 1.3 vs 1.5 ± 1.6; mean age 60 years in both groups]. All patients underwent successful ablation and completed study assessments. Clinically silent, new MRI diffusion weighted imaging cerebral lesions were observed in 8 patients (30%) in the RFB group and 1 patient (7%) in the control group, and 11 susceptibility weighted imaging lesions in the RFB group and 1 in the control group. Endoscopy showed a minor thermal injury in 1 patient in the RFB group. Conclusion An increased rate of clinically silent cerebral events was seen in the RFB group. A low rate of esophageal thermal injury was observed.
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He M, Qiu J, Bai Y, Wang Y, Hu M, Chen G. Non-pharmaceutical Interventions for Hypertrophic Cardiomyopathy: A Mini Review. Front Cardiovasc Med 2021; 8:695247. [PMID: 34722651 PMCID: PMC8553933 DOI: 10.3389/fcvm.2021.695247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/20/2021] [Indexed: 11/13/2022] Open
Abstract
Hypertrophic cardiomyopathy is an inherited cardiovascular disease, and 70% of patients have left ventricular outflow tract obstruction. Ventricular septal myectomy has been the gold standard treatment for most patients with refractory symptoms. Due to higher mortality associated with medical facilities with less experience, alcohol septal ablation has been accepted as an alternative to conventional surgical myectomy. It offers lower all-cause in-hospital complications and mortality, which could be potentially more preferable for patients with serious comorbidities. In recent years, radiofrequency ablation, providing another option with reproducibility and a low risk of permanent atrioventricular block, has become an effective invasive treatment to relieve left ventricular outflow tract obstruction. Moreover, substantial progress has been made in gene therapy for hypertrophic cardiomyopathy. The principal objective of this review is to present recent advances in non-pharmaceutical interventions in hypertrophic cardiomyopathy.
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Affiliation(s)
- Miaomiao He
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jie Qiu
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yang Bai
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Wang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mei Hu
- Health Management Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guangzhi Chen
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Yan S, Gu K, Wu X, Wang W. Computer simulation study on the effect of electrode-tissue contact force on thermal lesion size in cardiac radiofrequency ablation. Int J Hyperthermia 2020; 37:37-48. [PMID: 31918588 DOI: 10.1080/02656736.2019.1708482] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
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 = a × CFb (Lesion Depth = 3.17 × CF0.14 and Lesion Width = 5.17 × CF0.14).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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Affiliation(s)
- Shengjie Yan
- Electronic Engineering Department, Fudan University, Shanghai, China
| | - Kaihao Gu
- Electronic Engineering Department, Fudan University, Shanghai, China
| | - Xiaomei Wu
- Electronic Engineering Department, Fudan University, Shanghai, China.,Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Fudan University, Shanghai, China.,Shanghai Engineering Research Center of Assistive Devices, Shanghai, China
| | - Weiqi Wang
- Electronic Engineering Department, Fudan University, Shanghai, China
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