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Ijima Y, Masnok K, Perez JJ, González-Suárez A, Berjano E, Watanabe N. Ablation catheter-induced mechanical deformation in myocardium: computer modeling and ex vivo experiments. Med Biol Eng Comput 2024:10.1007/s11517-024-03135-7. [PMID: 38822997 DOI: 10.1007/s11517-024-03135-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 05/18/2024] [Indexed: 06/03/2024]
Abstract
Cardiac catheter ablation requires an adequate contact between myocardium and catheter tip. Our aim was to quantify the relationship between the contact force (CF) and the resulting mechanical deformation induced by the catheter tip using an ex vivo model and computational modeling. The catheter tip was inserted perpendicularly into porcine heart samples. CF values ranged from 10 to 80 g. The computer model was built to simulate the same experimental conditions, and it considered a 3-parameter Mooney-Rivlin model based on hyper-elastic material. We found a strong correlation between the CF and insertion depth (ID) (R2 = 0.96, P < 0.001), from 0.7 ± 0.3 mm at 10 g to 6.9 ± 0.1 mm at 80 g. Since the surface deformation was asymmetrical, two transversal diameters (minor and major) were identified. Both diameters were strongly correlated with CF (R2 ≥ 0.95), from 4.0 ± 0.4 mm at 20 g to 10.3 ± 0.0 mm at 80 g (minor), and from 6.4 ± 0.7 mm at 20 g to 16.7 ± 0.1 mm at 80 g (major). An optimal fit between computer and experimental results was achieved, with a prediction error of 0.74 and 0.86 mm for insertion depth and mean surface diameter, respectively.
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Affiliation(s)
- Yukako Ijima
- Biofluid Science and Engineering Laboratory, Global Course of Engineering and Science, Graduate School of Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minuma-Ku, Saitama-City, Saitama, 337-8570, Japan
| | - Kriengsak Masnok
- Biofluid Science and Engineering Laboratory, Global Course of Engineering and Science, Graduate School of Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minuma-Ku, Saitama-City, Saitama, 337-8570, Japan
- Department of Industrial Engineering, Faculty of Engineering, Srinakharinwirot University, Ongkharak, Nakhon Nayok, Thailand
| | - Juan J Perez
- BioMIT, Department of Electronic Engineering, Universitat Politecnica de Valencia, Camino de Vera, 46022, Valencia, Spain
| | - Ana González-Suárez
- Translational Medical Device Lab, School of Medicine, University of Galway, Galway, Ireland
- Universidad Internacional de Valencia, Valencia, Spain
| | - Enrique Berjano
- BioMIT, Department of Electronic Engineering, Universitat Politecnica de Valencia, Camino de Vera, 46022, Valencia, Spain.
| | - Nobuo Watanabe
- Biofluid Science and Engineering Laboratory, Global Course of Engineering and Science, Graduate School of Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minuma-Ku, Saitama-City, Saitama, 337-8570, Japan.
- Biomedical Engineering Course, Dept. of Bio-Science and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minuma-Ku, Saitama-City, Saitama, 337-8570, Japan.
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Hossain SMC, Zakaria JB, Ferdows M, Bangalee MZI, Alam MS, Zhao G. Computer simulation-based nanothermal field and tissue damage analysis for cardiac tumor ablation. Med Biol Eng Comput 2024; 62:1549-1567. [PMID: 38308669 DOI: 10.1007/s11517-024-03017-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 01/05/2024] [Indexed: 02/05/2024]
Abstract
Radiofrequency ablation is a nominally invasive technique to eradicate cancerous or non-cancerous cells by heating. However, it is still hampered to acquire a successful cell destruction process due to inappropriate RF intensities that will not entirely obliterate tumorous tissues, causing in treatment failure. In this study, we are acquainted with a nanoassisted RF ablation procedure of cardiac tumor to provide better outcomes for long-term survival rate without any recurrences. A three-dimensional thermo-electric energy model is employed to investigate nanothermal field and ablation efficiency into the left atrium tumor. The cell death model is adopted to quantify the degree of tissue injury while injecting the Fe3O4 nanoparticles concentrations up to 20% into the target tissue. The results reveal that when nanothermal field extents as a function of tissue depth (10 mm) from the electrode tip, the increasing thermal rates were approximately 0.54362%, 3.17039%, and 7.27397% for the particle concentration levels of 7%, 10%, and 15% compared with no-particle case. In the 7% Fe3O4 nanoparticles, 100% fractional damage index is achieved after ablation time of 18 s whereas tissue annihilation approach proceeds longer to complete for no-particle case. The outcomes indicate that injecting nanoparticles may lessen ablation time in surgeries and prevent damage to adjacent healthy tissue.
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Affiliation(s)
- S M C Hossain
- Department of Applied Mathematics, University of Dhaka, Dhaka, 1000, Bangladesh.
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei, 230027, China.
| | - J B Zakaria
- Department of Applied Mathematics, University of Dhaka, Dhaka, 1000, Bangladesh
| | - M Ferdows
- Department of Applied Mathematics, University of Dhaka, Dhaka, 1000, Bangladesh
| | - M Z I Bangalee
- Department of Applied Mathematics, University of Dhaka, Dhaka, 1000, Bangladesh
| | - M S Alam
- Department of Mathematics, Jagannath University, Dhaka, 1100, Bangladesh
| | - G Zhao
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei, 230027, China.
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3
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Gomez Bustamante T, Mercado Montoya M, Berjano E, González-Suárez A, Kulstad E. Proactive esophageal cooling during laser cardiac ablation: A computer modeling study. Lasers Surg Med 2024; 56:392-403. [PMID: 38436122 DOI: 10.1002/lsm.23774] [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: 08/28/2023] [Revised: 02/09/2024] [Accepted: 02/17/2024] [Indexed: 03/05/2024]
Abstract
BACKGROUND AND OBJECTIVES Laser ablation is increasingly used to treat atrial fibrillation (AF). However, atrioesophageal injury remains a potentially serious complication. While proactive esophageal cooling (PEC) reduces esophageal injury during radiofrequency ablation, the effects of PEC during laser ablation have not previously been determined. We aimed to evaluate the protective effects of PEC during laser ablation of AF by means of a theoretical study based on computer modeling. METHODS Three-dimensional mathematical models were built for 20 different cases including a fragment of atrial wall (myocardium), epicardial fat (adipose tissue), connective tissue, and esophageal wall. The esophagus was considered with and without PEC. Laser-tissue interaction was modeled using Beer-Lambert's law, Pennes' Bioheat equation was used to compute the resultant heating, and the Arrhenius equation was used to estimate the fraction of tissue damage (FOD), assuming a threshold of 63% to assess induced necrosis. We modeled laser irradiation power of 8.5 W over 20 s. Thermal simulations extended up to 250 s to account for thermal latency. RESULTS PEC significantly altered the temperature distribution around the cooling device, resulting in lower temperatures (around 22°C less in the esophagus and 9°C in the atrial wall) compared to the case without PEC. This thermal reduction translated into the absence of transmural lesions in the esophagus. The esophagus was thermally damaged only in the cases without PEC and with a distance equal to or shorter than 3.5 mm between the esophagus and endocardium (inner boundary of the atrial wall). Furthermore, PEC demonstrated minimal impact on the lesion created across the atrial wall, either in terms of maximum temperature or FOD. CONCLUSIONS PEC reduces the potential for esophageal injury without degrading the intended cardiac lesions for a variety of different tissue thicknesses. Thermal latency may influence lesion formation during laser ablation and may play a part in any collateral damage.
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Affiliation(s)
| | | | - Enrique Berjano
- Department of Electronic Engineering, BioMIT, Universitat Politècnica de València, Spain
| | - Ana González-Suárez
- Translational Medical Device Lab, School of Medicine, Lambe Institute for Translational Research, University of Galway, Ireland
- Valencian International University, Valencia, Spain
| | - Erik Kulstad
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
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4
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Sun Y, Zhu X, Nakamura K, Wang S. Evaluation of lesion characteristics and baseline impedance on high-power short-duration radiofrequency catheter ablation using computer simulation. Heart Vessels 2023; 38:1459-1467. [PMID: 37650926 DOI: 10.1007/s00380-023-02300-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 08/02/2023] [Indexed: 09/01/2023]
Abstract
Myocardium baseline impedance (BI) is an important factor in ablation effectiveness. This study examined the performance of low-power and long-duration (LPLD), high-power and short-duration (HPSD) ablation at different BIs by computer simulation. A 3D model of the ablation region was constructed for simulation, and in vitro experiments were performed to validate the simulation. Three ablation power and duration configurations of 30 W/30 s, 50 W/10 s, and 90 W/5 s were used for simulation with BI values of 90, 100, 110, 120, 130, and 140 Ω. Roll-off time and ablation volume were measured to evaluate ablation results. The simulation is consistent with the in vitro experiments. When BI is changed from 90 [Formula: see text] to 140 [Formula: see text], the lesion volume over 50 °C with BI of 140 [Formula: see text] was reduced by 6.3%, 6.7%, and 7.3% for 30 W/30 s, 50 W/10 s, and 90 W/5 s configurations, respectively, and the lesion volume over 100 °C was reduced by 62.8%, 49.7%, and 22.5% under 30 W/30 s, 50 W/10 s, and 90 W/5 s, respectively. Simulation results revealed that HPSD (vHPSD) and LPLD ablation were more affected by changes in BI in the lesion volumes over 50 °C and 100 °C, respectively, and demonstrated that resistive and conductive heating were the main heating effects in HPSD (vHPSD) and LPLD, respectively.
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Affiliation(s)
- Yao Sun
- Graduate School of Computer Science and Engineering, The University of Aizu, Aizuwakamatsu, Japan
| | - Xin Zhu
- Graduate School of Computer Science and Engineering, The University of Aizu, Aizuwakamatsu, Japan
| | - Keijiro Nakamura
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Meguro, Tokyo, 153-8515, Japan.
| | - Shuyu Wang
- Graduate School of Computer Science and Engineering, The University of Aizu, Aizuwakamatsu, Japan
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Dunne E, Baena-Montes JM, Donaghey K, Clarke C, Kraśny MJ, Amin B, O’Halloran T, Quinlan LR, Elahi A, O’Halloran M. A Predictive and an Optimization Mathematical Model for Device Design in Cardiac Pulsed Field Ablation Using Design of Experiments. J Cardiovasc Dev Dis 2023; 10:423. [PMID: 37887870 PMCID: PMC10607717 DOI: 10.3390/jcdd10100423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/19/2023] [Accepted: 09/26/2023] [Indexed: 10/28/2023] Open
Abstract
Cardiac catheter ablation (CCA) is a common method used to correct cardiac arrhythmia. Pulsed Field Ablation (PFA) is a recently-adapted CCA technology whose ablation is dependent on electrode and waveform parameters (factors). In this work, the use of the Design of Experiments (DoE) methodology is investigated for the design and optimization of a PFA device. The effects of the four factors (input voltage, electrode spacing, electrode width, and on-time) and their interactions are analyzed. An empirical model is formed to predict and optimize the ablation size responses. Based on the ranges tested, the significant factors were the input voltage, the electrode spacing, and the on time, which is in line with the literature. Two-factor interactions were found to be significant and need to be considered in the model. The resulting empirical model was found to predict ablation sizes with less than 2.1% error in the measured area and was used for optimization. The findings and the strong predictive model developed highlight that the DoE approach can be used to help determine PFA device design, to optimize for certain ablation zone sizes, and to help inform device design to tackle specific cardiac arrhythmias.
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Affiliation(s)
- Eoghan Dunne
- Translational Medical Device Lab (TMD Lab), Lambe Institute for Translational Research, School of Medicine, University of Galway, H91 TK33 Galway, Ireland
| | - Jara M. Baena-Montes
- Physiology and Cellular Physiology Research Laboratory, CÚRAM SFI Centre for Research in Medical Devices, School of Medicine, Human Biology Building, University of Galway, H91 TK33 Galway, Ireland
| | - Kevin Donaghey
- AuriGen Medical, GMIT Innovation Hubs, H91 DCH9 Galway, Ireland
| | - Cormac Clarke
- AuriGen Medical, GMIT Innovation Hubs, H91 DCH9 Galway, Ireland
| | - Marcin J. Kraśny
- Translational Medical Device Lab (TMD Lab), Lambe Institute for Translational Research, School of Medicine, University of Galway, H91 TK33 Galway, Ireland
- Smart Sensors Lab, Lambe Institute for Translational Research, School of Medicine, University of Galway, H91 TK33 Galway, Ireland
| | - Bilal Amin
- Translational Medical Device Lab (TMD Lab), Lambe Institute for Translational Research, School of Medicine, University of Galway, H91 TK33 Galway, Ireland
- Smart Sensors Lab, Lambe Institute for Translational Research, School of Medicine, University of Galway, H91 TK33 Galway, Ireland
- Electrical & Electronic Engineering, College of Science and Engineering, University of Galway, H91 TK33 Galway, Ireland
| | - Tony O’Halloran
- AuriGen Medical, GMIT Innovation Hubs, H91 DCH9 Galway, Ireland
| | - Leo R. Quinlan
- Physiology and Cellular Physiology Research Laboratory, CÚRAM SFI Centre for Research in Medical Devices, School of Medicine, Human Biology Building, University of Galway, H91 TK33 Galway, Ireland
| | - Adnan Elahi
- Translational Medical Device Lab (TMD Lab), Lambe Institute for Translational Research, School of Medicine, University of Galway, H91 TK33 Galway, Ireland
- Smart Sensors Lab, Lambe Institute for Translational Research, School of Medicine, University of Galway, H91 TK33 Galway, Ireland
- Electrical & Electronic Engineering, College of Science and Engineering, University of Galway, H91 TK33 Galway, Ireland
| | - Martin O’Halloran
- Translational Medical Device Lab (TMD Lab), Lambe Institute for Translational Research, School of Medicine, University of Galway, H91 TK33 Galway, Ireland
- Electrical & Electronic Engineering, College of Science and Engineering, University of Galway, H91 TK33 Galway, Ireland
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Pérez JJ, Berjano E, González-Suárez A. How far the zone of heat-induced transient block extends beyond the lesion during RF catheter cardiac ablation. Int J Hyperthermia 2023; 40:2163310. [PMID: 36592987 DOI: 10.1080/02656736.2022.2163310] [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: 01/04/2023] Open
Abstract
PURPOSE While radiofrequency catheter ablation (RFCA) creates a lesion consisting of the tissue points subjected to lethal heating, the sublethal heating (SH) undergone by the surrounding tissue can cause transient electrophysiological block. The size of the zone of heat-induced transient block (HiTB) has not been quantified to date. Our objective was to use computer modeling to provide an initial estimate. METHODS AND MATERIALS We used previous experimental data together with the Arrhenius damage index (Ω) to fix the Ω values that delineate this zone: a lower limit of 0.1-0.4 and upper limit of 1.0 (lesion boundary). An RFCA computer model was used with different power-duration settings, catheter positions and electrode insertion depths, together with dispersion of the tissue's electrical and thermal characteristics. RESULTS The HiTB zone extends in depth to a minimum and maximum distance of 0.5 mm and 2 mm beyond the lesion limit, respectively, while its maximum width varies with the energy delivered, extending to a minimum of 0.6 mm and a maximum of 2.5 mm beyond the lesion, reaching 3.5 mm when high energy settings are used (25 W-20s, 500 J). The dispersion of the tissue's thermal and electrical characteristics affects the size of the HiTB zone by ±0.3 mm in depth and ±0.5 mm in maximum width. CONCLUSIONS Our results suggest that the size of the zone of heat-induced transient block during RFCA could extend beyond the lesion limit by a maximum of 2 mm in depth and approximately 2.5 mm in width.
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Affiliation(s)
- Juan J Pérez
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, Valencia, Spain
| | - Enrique Berjano
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, Valencia, Spain
| | - Ana González-Suárez
- School of Engineering, University of Galway, Galway, Ireland.,Translational Medical Device Lab, University of Galway, Galway, Ireland
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Berjano E, González-Suárez A. How lesion size grows after applying a second RF pulse on the same site. J Cardiovasc Electrophysiol 2022; 33:2673. [PMID: 36251266 DOI: 10.1111/jce.15707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 09/17/2022] [Indexed: 12/15/2022]
Affiliation(s)
- Enrique Berjano
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, Valencia, Spain
| | - Ana González-Suárez
- School of Engineering, University of Galway, Galway, Ireland.,Translational Medical Device Lab, University of Galway, Galway, Ireland
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Limitations of Baseline Impedance, Impedance Drop and Current for Radiofrequency Catheter Ablation Monitoring: Insights from In silico Modeling. J Cardiovasc Dev Dis 2022; 9:jcdd9100336. [PMID: 36286288 PMCID: PMC9604830 DOI: 10.3390/jcdd9100336] [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: 08/25/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 11/06/2022] Open
Abstract
Background: Baseline impedance, radiofrequency current, and impedance drop during radiofrequency catheter ablation are thought to predict effective lesion formation. However, quantifying the contributions of local versus remote impedances provides insights into the limitations of indices using those parameters. Methods: An in silico model of left atrial radiofrequency catheter ablation was used based on human thoracic measurements and solved for (1) initial impedance (Z), (2) percentage of radiofrequency power delivered to the myocardium and blood (3) total radiofrequency current, (4) impedance drop during heating, and (5) lesion size after a 25 W−30 s ablation. Remote impedance was modeled by varying the mixing ratio between skeletal muscle and fat. Local impedance was modeled by varying insertion depth of the electrode (ID). Results: Increasing the remote impedance led to increased baseline impedance, lower system current delivery, and reduced lesion size. For ID = 0.5 mm, Z ranged from 115 to 132 Ω when fat percentage varied from 20 to 80%, resulting in a decrease in the RF current from 472 to 347 mA and a slight decrease in lesion size from 5.6 to 5.1 mm in depth, and from 9.2 to 8.0 mm in maximum width. In contrast, increasing the local impedance led to lower system current but larger lesions. For a 50% fat−muscle mixture, Z ranged from 118 to 138 Ω when ID varied from 0.3 to 1.9 mm, resulting in a decrease in the RF current from 463 to 443 mA and an increase in lesion size, from 5.2 up to 7.5 mm in depth, and from 8.4 up to 11.6 mm in maximum width. In cases of nearly identical Z but different contributions of local and remote impedance, markedly different lesions sizes were observed despite only small differences in RF current. Impedance drop better predicted lesion size (R2 > 0.93) than RF current (R2 < 0.1). Conclusions: Identical baseline impedances and observed RF currents can lead to markedly different lesion sizes with different relative contributions of local and remote impedances to the electrical circuit. These results provide mechanistic insights into the advantage of measuring local impedance and identifies potential limitations of indices incorporating baseline impedance or current to predict lesion quality.
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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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10
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Petras A, Moreno Weidmann Z, Echeverría Ferrero M, Leoni M, Guerra JM, Gerardo-Giorda L. Impact of electrode tip shape on catheter performance in cardiac radiofrequency ablation. Heart Rhythm O2 2022; 3:699-705. [PMID: 36589920 PMCID: PMC9795254 DOI: 10.1016/j.hroo.2022.07.014] [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] [Indexed: 01/04/2023] Open
Abstract
Background The role of catheter tip shape on the safety and efficacy of radiofrequency (RF) ablation has been overlooked, although differences have been observed in clinical and research fields. Objective The purpose of this study was to analyze the role of electrode tip shape in RF ablation using a computational model. Methods We simulated 108 RF ablations through a realistic 3-dimensional computational model considering 2 clinically used, open-irrigated catheters (spherical and cylindrical tip), varying contact force (CF), blood flow, and irrigation. Lesions are defined by the 50°C isotherm contour and evaluated by means of width, depth, depth at maximum width, and volume. Ablations are deemed as safe, critical (tissue temperature >90°C), and pop (tissue temperature >100°C). Results Tissue-electrode contact is less for the spherical tip at low CF but the relationship is inverted at high CF. At low CF, the cylindrical tip generates deeper and wider lesions and a 4-fold larger volume. With increasing CF, the lesions generated by the spherical tip become comparable to those generated by the cylindrical tip. The 2 tips feature different safety profiles: CF and power are the main determinants of pops for the spherical tip; power is the main factor for the cylindrical tip; and CF has a marginal effect. The cylindrical tip is more prone to pop generation at higher powers. Saline irrigation and blood flow effect do not depend on tip shape. Conclusion Tip shape determines the performance of ablation catheters and has a major impact on their safety profile. The cylindrical tip shows more predictable behavior in a wide range of CF values.
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Affiliation(s)
| | - Zoraida Moreno Weidmann
- Department of Cardiology, Hospital de la Santa Creu i Sant Pau, IIB SANT PAU, Universitat Autònoma de Barcelona, CIBERCV, Barcelona, Spain
| | | | | | - Jose M. Guerra
- Department of Cardiology, Hospital de la Santa Creu i Sant Pau, IIB SANT PAU, Universitat Autònoma de Barcelona, CIBERCV, Barcelona, Spain,Address reprint requests and correspondence: Dr Jose M. Guerra, Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Sant Antoni M. Claret 167, 08025 Barcelona, Spain.
| | - Luca Gerardo-Giorda
- RICAM, Austrian Academy of Sciences, Linz, Austria,Institute for Mathematical Methods in Medicine and Data-Based Modelling, Johannes Kepler University, Linz, Austria
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Vicentini M, Vassallo M, Ferrero R, Androulakis I, Manzin A. In silico evaluation of adverse eddy current effects in preclinical tests of magnetic hyperthermia. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 223:106975. [PMID: 35792363 DOI: 10.1016/j.cmpb.2022.106975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/17/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE Magnetic hyperthermia is an oncological therapy that employs magnetic nanoparticles activated by alternating current (AC) magnetic fields with frequencies between 50 kHz and 1 MHz, to release heat in a diseased tissue and produce a local temperature increase of about 5 °C. To assess the treatment efficacy, in vivo tests on murine models (mice and rats) are typically performed. However, these are often carried out without satisfying the biophysical constraints on the electromagnetic (EM) field exposure, with consequent generation of hot spots and undesirable heating of healthy tissues. Here, we investigate possible adverse eddy current effects, to estimate AC magnetic field parameters (frequency and amplitude) that can potentially guarantee safe animal tests of magnetic hyperthermia. METHODS The analysis is performed through in silico modelling by means of finite element simulation tools, specifically developed to study eddy current effects in computational animal models, during magnetic hyperthermia treatments. The numerical tools enable us to locally evaluate the specific absorption rate (SAR) and the produced temperature increase, under different field exposure conditions. RESULTS The simulation outcomes demonstrate that in mice with weight lower than 30 g the thermal effects induced by AC magnetic fields are very weak, also when slightly overcoming the Hergt-Dutz limit, that is the product of the magnetic field amplitude and frequency should be lower than 5·109 A/(m·s). Conversely, we observe significant temperature increases in 500 g rats, amplified when the field is applied transversally to the body longitudinal axis. A strong mitigation of side-effects can be achieved by introducing water boluses or by applying focused fields. CONCLUSIONS The developed physics-based modelling approach has proved to be a useful predictive tool for the optimization of preclinical tests of magnetic hyperthermia, allowing the identification of proper EM field conditions and the design of setups that guarantee safe levels of field exposure during animal treatments. In such contest, the obtained results can be considered as valid indicators to assess reference levels for animal testing of biomedical techniques that involve EM fields, like magnetic hyperthermia, thus complying with the Directive 2010/63/EU on the protection of animals used for scientific purposes.
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Affiliation(s)
- Marta Vicentini
- Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135 Torino, Italy; Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
| | - Marta Vassallo
- Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135 Torino, Italy; Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
| | - Riccardo Ferrero
- Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135 Torino, Italy
| | - Ioannis Androulakis
- Erasmus MC Cancer Institute, University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Alessandra Manzin
- Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135 Torino, Italy.
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Pérez JJ, Berjano E, González-Suárez A. In-Silico Modeling to Compare Radiofrequency-Induced Thermal Lesions Created on Myocardium and Thigh Muscle. Bioengineering (Basel) 2022; 9:bioengineering9070329. [PMID: 35877380 PMCID: PMC9312255 DOI: 10.3390/bioengineering9070329] [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] [Received: 05/26/2022] [Revised: 07/11/2022] [Accepted: 07/18/2022] [Indexed: 11/16/2022] Open
Abstract
Beating heart (BH) and thigh muscle (TM) are two pre-clinical models aimed at studying the lesion sizes created by radiofrequency (RF) catheters in cardiac ablation. Previous experimental results have shown that thermal lesions created in the TM are slightly bigger than in the BH. Our objective was to use in-silico modeling to elucidate some of the causes of this difference. In-silico RF ablation models were created using the Arrhenius function to estimate lesion size under different energy settings (25 W/20 s, 50 W/6 s and 90 W/4 s) and parallel, 45° and perpendicular catheter positions. The models consisted of homogeneous tissue: myocardium in the BH model and striated muscle in the TM model. The computer results showed that the lesion sizes were generally bigger in the TM model and the differences depended on the energy setting, with hardly any differences at 90 W/4 s but with differences of 1 mm in depth and 1.5 m in width at 25 W/20 s. The higher electrical conductivity of striated muscle (0.446 S/m) than that of the myocardium (0.281 S/m) is possibly one of the causes of the higher percentage of RF energy delivered to the tissue in the TM model, with differences between models of 2–5% at 90 W/4 s, ~9% at 50 W/6 s and ~10% at 25 W/20 s. Proximity to the air–blood interface (just 2 cm from the tissue surface) artificially created in the TM model to emulate the cardiac cavity had little effect on lesion size. In conclusion, the TM-based experimental model creates fairly similar-sized lesions to the BH model, especially in high-power short-duration ablations (50 W/6 s and 90 W/4 s). Our computer results suggest that the higher electrical conductivity of striated muscle could be one of the causes of the slightly larger lesions in the TM model.
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Affiliation(s)
- Juan J. Pérez
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, 46022 Valencia, Spain; (J.J.P.); (E.B.)
| | - Enrique Berjano
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, 46022 Valencia, Spain; (J.J.P.); (E.B.)
| | - Ana González-Suárez
- Electrical and Electronic Engineering, Translational Medical Device Lab, National University of Ireland Galway, H91 TK33 Galway, Ireland
- Correspondence:
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Low-energy (360 J) radiofrequency catheter ablation using moderate power - short duration: proof of concept based on in silico modeling. J Interv Card Electrophysiol 2022:10.1007/s10840-022-01292-z. [PMID: 35796934 DOI: 10.1007/s10840-022-01292-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/27/2022] [Indexed: 10/17/2022]
Abstract
BACKGROUND Pilot clinical studies suggest that very high power-very short duration (vHPvSD, 90 W/4 s, 360 J energy) is a feasible and safe technique for ablation of atrial fibrillation (AF), compared with standard applications using moderate power-moderate duration (30 W/30 s, 900 J energy). However, it is unclear whether alternate power and duration settings for the delivery of the same total energy would result in similar lesion formation. This study compares temperature dynamics and lesion size at different power-duration settings for the delivery of equivalent total energy (360 J). METHODS An in silico model of radiofrequency (RF) ablation was created using the Arrhenius function to estimate lesion size under different power-duration settings with energy balanced at 360 J: 30 W/12 s (MPSD), 50 W/7.2 s (HPSD), and 90 W/4 s (vHPvSD). Three catheter orientations were considered: parallel, 45°, and perpendicular. RESULTS In homogenous tissue, vHPvSD and HPSD produced similar size lesions independent of catheter orientation, both of which were slightly larger than MPSD (lesion size 0.1 mm deeper, ~ 0.7 mm wider, and ~ 25 mm3 larger volume). When considering heterogeneous tissue, these differences were smaller. Tissue reached higher absolute temperature with vHPvSD and HPSD (5-8 °C higher), which might increase risk of collateral tissue injury or steam pops. CONCLUSION Ablation for AF using MPSD or HPSD may be a feasible alternative to vHPvSD ablation given similar size lesions with similar total energy delivery (360 J). Lower absolute tissue temperature and slower heating may reduce risk of collateral tissue injury and steam pops associated with vHPvSD and longer applications using moderate power.
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Abstract
Significant research efforts have been devoted in the past decades to accurately modelling the complex heat transfer phenomena within biological tissues. These modeling efforts and analysis have assisted in a better understanding of the intricacies of associated biological phenomena and factors that affect the treatment outcomes of hyperthermic therapeutic procedures. In this contribution, we report a three-dimensional non-Fourier bio-heat transfer model of cardiac ablation that accounts for the three-phase-lags (TPL) in the heat propagation, viz., lags due to heat flux, temperature gradient, and thermal displacement gradient. Finite element-based COMSOL Multiphysics software has been utilized to predict the temperature distributions and ablation volumes. A comparative analysis has been conducted to report the variation in the treatment outcomes of cardiac ablation considering different bio-heat transfer models. The effect of variations in the magnitude of different phase lags has been systematically investigated. The fidelity and integrity of the developed model have been evaluated by comparing the results of the developed model with the analytical results of the recent studies available in the literature. This study demonstrates the importance of considering non-Fourier lags within biological tissue for predicting more accurately the characteristics important for the efficient application of thermal therapies.
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Pérez JJ, Nadal E, Berjano E, González-Suárez A. Computer modeling of radiofrequency cardiac ablation including heartbeat-induced electrode displacement. Comput Biol Med 2022; 144:105346. [DOI: 10.1016/j.compbiomed.2022.105346] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/13/2022] [Accepted: 02/21/2022] [Indexed: 12/12/2022]
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Montoya MM, Bustamante TG, Berjano E, Mickelsen SR, Daniels JD, Arango PH, Schieber J, Kulstad E. Proactive esophageal cooling protects against thermal insults during high-power short-duration radiofrequency cardiac ablation. Int J Hyperthermia 2022; 39:1202-1212. [PMID: 36104029 PMCID: PMC9771690 DOI: 10.1080/02656736.2022.2121860] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Proactive cooling with a novel cooling device has been shown to reduce endoscopically identified thermal injury during radiofrequency (RF) ablation for the treatment of atrial fibrillation using medium power settings. We aimed to evaluate the effects of proactive cooling during high-power short-duration (HPSD) ablation. METHODS A computer model accounting for the left atrium (1.5 mm thickness) and esophagus including the active cooling device was created. We used the Arrhenius equation to estimate the esophageal thermal damage during 50 W/ 10 s and 90 W/ 4 s RF ablations. RESULTS With proactive esophageal cooling in place, temperatures in the esophageal tissue were significantly reduced from control conditions without cooling, and the resulting percentage of damage to the esophageal wall was reduced around 50%, restricting damage to the epi-esophageal region and consequently sparing the remainder of the esophageal tissue, including the mucosal surface. Lesions in the atrial wall remained transmural despite cooling, and maximum width barely changed (<0.8 mm). CONCLUSIONS Proactive esophageal cooling significantly reduces temperatures and the resulting fraction of damage in the esophagus during HPSD ablation. These findings offer a mechanistic rationale explaining the high degree of safety encountered to date using proactive esophageal cooling, and further underscore the fact that temperature monitoring is inadequate to avoid thermal damage to the esophagus.
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Affiliation(s)
| | | | - Enrique Berjano
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, Spain
| | | | - James D. Daniels
- University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Jay Schieber
- Illinois Institute of Technology, Chicago, IL, USA
| | - Erik Kulstad
- University of Texas Southwestern Medical Center, Dallas, TX, USA
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