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Bayer JD, Sobota V, Bear LR, Haïssaguerre M, Vigmond EJ. A His bundle pacing protocol for suppressing ventricular arrhythmia maintenance and improving defibrillation efficacy. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 253:108239. [PMID: 38823116 DOI: 10.1016/j.cmpb.2024.108239] [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: 01/08/2024] [Revised: 05/18/2024] [Accepted: 05/21/2024] [Indexed: 06/03/2024]
Abstract
BACKGROUND The excitable gap (EG), defined as the excitable tissue between two subsequent wavefronts of depolarization, is critical for maintaining reentry that underlies deadly ventricular arrhythmias. EG in the His-Purkinje Network (HPN) plays an important role in the maintenance of electrical wave reentry that underlies these arrhythmias. OBJECTIVE To determine if rapid His bundle pacing (HBP) during reentry reduces the amount of EG in the HPN and ventricular myocardium to suppress reentry maintenance and/or improve defibrillation efficacy. METHODS In a virtual human biventricular model, reentry was initiated with rapid line pacing followed by HBP delivered for 3, 6, or 9 s at pacing cycle lengths (PCLs) ranging from 10 to 300 ms (n=30). EG was calculated independently for the HPN and myocardium over each PCL. Defibrillation efficacy was assessed for each PCL by stimulating myocardial surface EG with delays ranging from 0.25 to 9 s (increments of 0.25 s, n=36) after the start of HBP. Defibrillation was successful if reentry terminated within 1 s after EG stimulation. This defibrillation protocol was repeated without HBP. To test the approach under different pathological conditions, all protocols were repeated in the model with right (RBBB) or left (LBBB) bundle branch block. RESULTS Compared to without pacing, HBP for >3 seconds reduced average EG in the HPN and myocardium across a broad range of PCLs for the default, RBBB, and LBBB models. HBP >6 seconds terminated reentrant arrhythmia by converting HPN activation to a sinus rhythm behavior in the default (6/30 PCLs) and RBBB (7/30 PCLs) models. Myocardial EG stimulation during HBP increased the number of successful defibrillation attempts by 3%-19% for 30/30 PCLs in the default model, 3%-6% for 14/30 PCLs in the RBBB model, and 3%-11% for 27/30 PCLs in the LBBB model. CONCLUSION HBP can reduce the amount of excitable gap and suppress reentry maintenance in the HPN and myocardium. HBP can also improve the efficacy of low-energy defibrillation approaches targeting excitable myocardium. HBP during reentrant arrhythmias is a promising anti-arrhythmic and defibrillation strategy.
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Affiliation(s)
- Jason D Bayer
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France; University of Bordeaux, Institut de Mathématiques de Bordeaux, UMR 5251, 33400, Talence, France.
| | - Vladimír Sobota
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France; University of Bordeaux, Institut de Mathématiques de Bordeaux, UMR 5251, 33400, Talence, France
| | - Laura R Bear
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France
| | - Michel Haïssaguerre
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France; Haut-Lévêque Cardiology Hospital, University Hospital Center (CHU) of Bordeaux, Pessac, France
| | - Edward J Vigmond
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France; University of Bordeaux, Institut de Mathématiques de Bordeaux, UMR 5251, 33400, Talence, France
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Rodriguez-Rivera GJ, Post A, John M, Buchan S, Bernard D, Razavi M, Cosgriff-Hernandez E. Injectable hydrogel electrodes as conduction highways to restore native pacing. Nat Commun 2024; 15:64. [PMID: 38167848 PMCID: PMC10762156 DOI: 10.1038/s41467-023-44419-0] [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: 08/21/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
There is an urgent clinical need for a treatment regimen that addresses the underlying pathophysiology of ventricular arrhythmias, the leading cause of sudden cardiac death. The current report describes the design of an injectable hydrogel electrode and successful deployment in a pig model with access far more refined than any current pacing modalities allow. In addition to successful cardiac capture and pacing, analysis of surface ECG tracings and three-dimensional electroanatomic mapping revealed a QRS morphology comparable to native sinus rhythm, strongly suggesting the hydrogel electrode captures the deep septal bundle branches and Purkinje fibers. In an ablation model, electroanatomic mapping data demonstrated that the activation wavefront from the hydrogel reaches the mid-myocardium and endocardium much earlier than current single-point pacing modalities. Such uniform activation of broad swaths of tissue enables an opportunity to minimize the delayed myocardial conduction of heterogeneous tissue that underpins re-entry. Collectively, these studies demonstrate the feasibility of a new pacing modality that most closely resembles native conduction with the potential to eliminate lethal re-entrant arrhythmias and provide painless defibrillation.
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Affiliation(s)
| | - Allison Post
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, Houston, TX, 77030, USA
| | - Mathews John
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, Houston, TX, 77030, USA
| | - Skylar Buchan
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, Houston, TX, 77030, USA
| | - Drew Bernard
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, Houston, TX, 77030, USA
| | - Mehdi Razavi
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, Houston, TX, 77030, USA.
- Division of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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Ramlugun GS, Kulkarni K, Pallares-Lupon N, Boukens BJ, Efimov IR, Vigmond EJ, Bernus O, Walton RD. A comprehensive framework for evaluation of high pacing frequency and arrhythmic optical mapping signals. Front Physiol 2023; 14:734356. [PMID: 36755791 PMCID: PMC9901579 DOI: 10.3389/fphys.2023.734356] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 01/09/2023] [Indexed: 01/24/2023] Open
Abstract
Introduction: High pacing frequency or irregular activity due to arrhythmia produces complex optical mapping signals and challenges for processing. The objective is to establish an automated activation time-based analytical framework applicable to optical mapping images of complex electrical behavior. Methods: Optical mapping signals with varying complexity from sheep (N = 7) ventricular preparations were examined. Windows of activation centered on each action potential upstroke were derived using Hilbert transform phase. Upstroke morphology was evaluated for potential multiple activation components and peaks of upstroke signal derivatives defined activation time. Spatially and temporally clustered activation time points were grouped in to wave fronts for individual processing. Each activation time point was evaluated for corresponding repolarization times. Each wave front was subsequently classified based on repetitive or non-repetitive events. Wave fronts were evaluated for activation time minima defining sites of wave front origin. A visualization tool was further developed to probe dynamically the ensemble activation sequence. Results: Our framework facilitated activation time mapping during complex dynamic events including transitions to rotor-like reentry and ventricular fibrillation. We showed that using fixed AT windows to extract AT maps can impair interpretation of the activation sequence. However, the phase windowing of action potential upstrokes enabled accurate recapitulation of repetitive behavior, providing spatially coherent activation patterns. We further demonstrate that grouping the spatio-temporal distribution of AT points in to coherent wave fronts, facilitated interpretation of isolated conduction events, such as conduction slowing, and to derive dynamic changes in repolarization properties. Focal origins precisely detected sites of stimulation origin and breakthrough for individual wave fronts. Furthermore, a visualization tool to dynamically probe activation time windows during reentry revealed a critical single static line of conduction slowing associated with the rotation core. Conclusion: This comprehensive analytical framework enables detailed quantitative assessment and visualization of complex electrical behavior.
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Affiliation(s)
- Girish S. Ramlugun
- IHU-Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France,Univ. Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique, Bordeaux, France
| | - Kanchan Kulkarni
- IHU-Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France,Univ. Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique, Bordeaux, France
| | - Nestor Pallares-Lupon
- IHU-Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France,Univ. Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique, Bordeaux, France
| | - Bastiaan J. Boukens
- Department of Physiology, Cardiovascular Research Institute Maastricht, University Maastricht, Maastricht, Netherlands,Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Igor R. Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States,Department of Biomedical Engineering, Northwestern University, Chicago, IL, United States,Department of Medicine, Northwestern University, Chicago, IL, United States
| | - Edward J. Vigmond
- IHU-Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France,Univ. Bordeaux, Centre National de la Recherche Scientifique (CNRS), Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France
| | - Olivier Bernus
- IHU-Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France,Univ. Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique, Bordeaux, France
| | - Richard D. Walton
- IHU-Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France,Univ. Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique, Bordeaux, France,*Correspondence: Richard D. Walton,
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Kulangareth NV, Magtibay K, Massé S, Krishnakumar Nair, Dorian P, Nanthakumar K, Umapathy K. An In-Silico model for evaluating the directional shock vectors in terminating and modulating rotors. Comput Biol Med 2022; 146:105665. [DOI: 10.1016/j.compbiomed.2022.105665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/03/2022] [Accepted: 05/19/2022] [Indexed: 11/27/2022]
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The Purkinje network plays a major role in low-energy ventricular defibrillation. Comput Biol Med 2021; 141:105133. [PMID: 34954609 DOI: 10.1016/j.compbiomed.2021.105133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/10/2021] [Accepted: 12/10/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND During ventricular fibrillation (VF), targeting the excitable gap (EG) of reentry throughout the myocardium with low-energy surface stimulation shows promise for painless defibrillation. However, the Purkinje network may provide alternative pathways for reentry to evade termination. This study investigates the role of the Purkinje network in painless defibrillation. METHODS In a computational human biventricular model featuring a Purkinje network, VF was initiated with 4 Hz epicardial pacing. Defibrillation was attempted by stimulating myocardial surface EG with a low-energy 2 ms duration pulse at 2x stimulus capture, which was administered at coupling intervals incremented by 0.25 s between 0.25 and 5 s after VF initiation. Defibrillation was accomplished if reentry ceased ≤ 1 s after the defibrillation pulse. The protocol was repeated with the Purkinje network and myocardial surface EG stimulated simultaneously, and again after uncoupling the Purkinje network from the myocardium. RESULTS VF with the Purkinje network coupled and uncoupled had comparable dominant frequency in the left (3.81 ± 0.44 versus 3.77 ± 0.53 Hz) and right (3.80 ± 0.37 versus 3.76 ± 0.48 Hz) ventricles. When uncoupling the Purkinje network, myocardial surface EG stimulation terminated VF for all defibrillation pulses. When coupled, myocardial EG surface stimulation terminated VF for only 55% of the defibrillation pulses, but improved to 100% when stimulated simultaneously with Purkinje network EG. Defibrillation failures were attributed to EG evading stimulation in the Purkinje network. CONCLUSIONS Defibrillation that exclusively targets myocardium can fail due to accessory pathways in the Purkinje network that allow for reentrant activity to evade termination and maintain VF. Painless defibrillation strategies should be adapted to include the Purkinje network.
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Moreno A, Walton RD, Bernus O, Vigmond EJ, Bayer JD. Low-energy, single-pulse surface stimulation defibrillates large mammalian ventricles. Heart Rhythm 2021; 19:308-317. [PMID: 34648972 DOI: 10.1016/j.hrthm.2021.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/27/2021] [Accepted: 10/06/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Strong electric shocks are the gold standard for ventricular defibrillation but are associated with pain and tissue damage. We hypothesized that targeting the excitable gap (EG) of reentry with low-energy surface stimulation is a less damaging and painless alternative for ventricular defibrillation. OBJECTIVE The purpose of this study was to determine the conditions under which low-energy surface stimulation defibrillates large mammalian ventricles. METHODS Low-energy surface stimulation was delivered with five electrodes that were 7 cm long and placed 1-2 cm apart on the endocardial and epicardial surfaces of perfused pig left ventricle (LV). Rapid pacing (>4 Hz) was used to induce reentry from a single electrode. A 2 ms defibrillation pulse ≤0.5 A was delivered from all electrodes with a varied time delay from the end of the induction protocol (0.1-5 seconds). Optical mapping was performed and arrhythmia dynamics analyzed. For mechanistic insight, simulations of the VF induction and defibrillation protocols were performed in silico with an LV model emulating the experimental conditions and electrodes placed 0.25-2 cm apart. RESULTS In living LV, reentry was induced with varying complexity and dominant frequencies ranging between 3.5 to 6.2 Hz over 8 seconds postinitiation. Low-energy defibrillation was achieved with energy <60 mJ and electrode separations up to 2 cm for less complex arrhythmia. In simulations, defibrillation consistently occurred when stimulation captured >75% of the EG, which blocked reentry <2.9 mm in front of the leading reentrant wavefront. CONCLUSION Defibrillation with low-energy, single-pulse surface stimulation is feasible with energies below the human pain threshold (100 mJ). Optimal defibrillation occurs when arrhythmia complexity is minimal and electrodes capture >75% of the EG.
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Affiliation(s)
- Angel Moreno
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France
| | - Richard D Walton
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, U1045, Bordeaux, France; INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Olivier Bernus
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, U1045, Bordeaux, France; INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Edward J Vigmond
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France
| | - Jason D Bayer
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France.
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Morrissey J, Mesquita FCP, Hochman-Mendez C, Taylor DA. Whole Heart Engineering: Advances and Challenges. Cells Tissues Organs 2021; 211:395-405. [PMID: 33640893 DOI: 10.1159/000511382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/26/2020] [Indexed: 11/19/2022] Open
Abstract
Bioengineering a solid organ for organ replacement is a growing endeavor in regenerative medicine. Our approach - recellularization of a decellularized cadaveric organ scaffold with human cells - is currently the most promising approach to building a complex solid vascularized organ to be utilized in vivo, which remains the major unmet need and a key challenge. The 2008 publication of perfusion-based decellularization and partial recellularization of a rat heart revolutionized the tissue engineering field by showing that it was feasible to rebuild an organ using a decellularized extracellular matrix scaffold. Toward the goal of clinical translation of bioengineered tissues and organs, there is increasing recognition of the underlying need to better integrate basic science domains and industry. From the perspective of a research group focusing on whole heart engineering, we discuss the current approaches and advances in whole organ engineering research as they relate to this multidisciplinary field's 3 major pillars: organ scaffolds, large numbers of cells, and biomimetic bioreactor systems. The success of whole organ engineering will require optimization of protocols to produce biologically-active scaffolds for multiple organ systems, and further technological innovation both to produce the massive quantities of high-quality cells needed for recellularization and to engineer a bioreactor with physiologic stimuli to recapitulate organ function. Also discussed are the challenges to building an implantable vascularized solid organ.
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Affiliation(s)
- Jacquelynn Morrissey
- Regenerative Medicine Research Department, Texas Heart Institute, Houston, Texas, USA
| | - Fernanda C P Mesquita
- Regenerative Medicine Research Department, Texas Heart Institute, Houston, Texas, USA
| | - Camila Hochman-Mendez
- Regenerative Medicine Research Department, Texas Heart Institute, Houston, Texas, USA
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Abstract
Stretchable conductive fabric (SCF) is a durable nontoxic textile material coated or blended with conductive metals. Unlike solid metal, SCF effectively conducts electricity with low resistance and maintains conductance when stretched. Thus, we hypothesized that SCF electrodes are more suitable for cardiac electrophysiology applications in beating hearts than traditional solid metal electrodes. Accordingly, we developed a straightforward protocol for fabricating customized SCF electrodes and then assessed their ability to electrically stimulate and record electrical signals from beating hearts. Compared to flexible copper electrodes, SCF electrodes had similar electrical resistance (112.50 ± 25.81 vs 157.85 ± 17.06 Ω, p = 0.09), activated cardiac tissue with lower stimulus strength (27.25 ± 3.52 vs 15.35 ± 2.15 mA, p = 0.0001), recorded stable electrograms with a higher signal-to-noise ratio (20.54 ± 1.09 vs 13.35 ± 1.46 dB, p = 0.04), and were noncorrosive and harmless to cardiac tissue or vasculature. These results support the use of SCF over metal electrodes for a wide range of cardiac electrophysiology applications in the beating heart.
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Holden AV, Begg GA, Bounford K, Stegemann B, Tayebjee MH. Phase Entrainment of Induced Ventricular Fibrillation: A Human Feasibility and Proof of Concept Study. J Atr Fibrillation 2019; 12:2217. [PMID: 32435345 DOI: 10.4022/jafib.2217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/19/2019] [Accepted: 09/21/2019] [Indexed: 11/10/2022]
Abstract
Cardioversion and defibrillation by a single high energy shock applied by myocardial or body surface electrodes is painful, causes long term tissue damage, and is associated with worsening long term outcomes, but is almost always required for treatment of ventricular fibrillation . As a initial step towards developing methods that can terminate ventricular arrhythmias painlessly, we aim to determine if pacing stimuli at a rate of 5/s applied via an implantable cardiac defibrillator (ICD) can modify human ventricular fibrillation. In 8 patients undergoing defibrillation testing of a new/exchanged intracardiac defibrillator, five seconds of pacing at five stimuli per second was applied during the 10-20 seconds of induced ventricular fibrillation before the defibrillation shock was automatically applied, and the cardiac electrograms recorded and analyzed. The high frequency pacing did not entrain the ventricular fibrillation, but altered the dominant frequency in all 8 patients, and modulated the phase computed via the Hilbert Transform, in four of the patients. In this pilot study we demonstrate that high frequency pacing applied via ICD electrodes during VF can alter the dominant frequency and modulate the probability density of the phase of the electrogram of the ventricular fibrillation.
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Affiliation(s)
- Arun V Holden
- School of Biomedical Sciences, University of Leeds, Leeds, LS2 9JT; UK
| | - Gordon A Begg
- West Yorkshire Arrhythmia Service, Leeds General Infirmary, Great George Street, Leeds, LS1 3EX, UK
| | - Katrina Bounford
- West Yorkshire Arrhythmia Service, Leeds General Infirmary, Great George Street, Leeds, LS1 3EX, UK
| | - Berthold Stegemann
- Medtronic Plc, Bakken Research Center, Endepolsdomein 5, 6229 GW Maastricht, The Netherlands
| | - Muzahir H Tayebjee
- West Yorkshire Arrhythmia Service, Leeds General Infirmary, Great George Street, Leeds, LS1 3EX, UK
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