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Clayton RH, Sridhar S. Re-entry in models of cardiac ventricular tissue with scar represented as a Gaussian random field. Front Physiol 2024; 15:1403545. [PMID: 39005500 PMCID: PMC11239552 DOI: 10.3389/fphys.2024.1403545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 06/10/2024] [Indexed: 07/16/2024] Open
Abstract
Introduction: Fibrotic scar in the heart is known to act as a substrate for arrhythmias. Regions of fibrotic scar are associated with slowed or blocked conduction of the action potential, but the detailed mechanisms of arrhythmia formation are not well characterised and this can limit the effective diagnosis and treatment of scar in patients. The aim of this computational study was to evaluate different representations of fibrotic scar in models of 2D 10 × 10 cm ventricular tissue, where the region of scar was defined by sampling a Gaussian random field with an adjustable length scale of between 1.25 and 10.0 mm. Methods: Cellular electrophysiology was represented by the Ten Tusscher 2006 model for human ventricular cells. Fibrotic scar was represented as a spatially varying diffusion, with different models of the boundary between normal and fibrotic tissue. Dispersion of activation time and action potential duration (APD) dispersion was assessed in each sample by pacing at an S1 cycle length of 400 ms followed by a premature S2 beat with a coupling interval of 323 ms. Vulnerability to reentry was assessed with an aggressive pacing protocol. In all models, simulated fibrosis acted to delay activation, to increase the dispersion of APD, and to generate re-entry. Results: A higher incidence of re-entry was observed in models with simulated fibrotic scar at shorter length scale, but the type of model used to represent fibrotic scar had a much bigger influence on the incidence of reentry. Discussion: This study shows that in computational models of fibrotic scar the effects that lead to either block or propagation of the action potential are strongly influenced by the way that fibrotic scar is represented in the model, and so the results of computational studies involving fibrotic scar should be interpreted carefully.
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Affiliation(s)
- Richard H Clayton
- Insigneo Institute for in-silico Medicine and Department of Computer Science, University of Sheffield, Sheffield, United Kingdom
| | - S Sridhar
- Insigneo Institute for in-silico Medicine and Department of Computer Science, University of Sheffield, Sheffield, United Kingdom
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2
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Masè M, Cristoforetti A, Pelloni S, Ravelli F. Systematic in-silico evaluation of fibrosis effects on re-entrant wave dynamics in atrial tissue. Sci Rep 2024; 14:11427. [PMID: 38763959 DOI: 10.1038/s41598-024-62002-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 05/13/2024] [Indexed: 05/21/2024] Open
Abstract
Despite the key role of fibrosis in atrial fibrillation (AF), the effects of different spatial distributions and textures of fibrosis on wave propagation mechanisms in AF are not fully understood. To clarify these aspects, we performed a systematic computational study to assess fibrosis effects on the characteristics and stability of re-entrant waves in electrically-remodelled atrial tissues. A stochastic algorithm, which generated fibrotic distributions with controlled overall amount, average size, and orientation of fibrosis elements, was implemented on a monolayer spheric atrial model. 245 simulations were run at changing fibrosis parameters. The emerging propagation patterns were quantified in terms of rate, regularity, and coupling by frequency-domain analysis of correspondent synthetic bipolar electrograms. At the increase of fibrosis amount, the rate of reentrant waves significantly decreased and higher levels of regularity and coupling were observed (p < 0.0001). Higher spatial variability and pattern stochasticity over repetitions was observed for larger amount of fibrosis, especially in the presence of patchy and compact fibrosis. Overall, propagation slowing and organization led to higher stability of re-entrant waves. These results strengthen the evidence that the amount and spatial distribution of fibrosis concur in dictating re-entry dynamics in remodeled tissue and represent key factors in AF maintenance.
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Affiliation(s)
- Michela Masè
- Laboratory of Biophysics and Translational Cardiology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, Via Sommarive 18, 38123, Povo, Trento, Italy.
| | - Alessandro Cristoforetti
- Laboratory of Biophysics and Translational Cardiology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, Via Sommarive 18, 38123, Povo, Trento, Italy
| | - Samuele Pelloni
- Laboratory of Biophysics and Translational Cardiology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, Via Sommarive 18, 38123, Povo, Trento, Italy
| | - Flavia Ravelli
- Laboratory of Biophysics and Translational Cardiology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, Via Sommarive 18, 38123, Povo, Trento, Italy
- CISMed-Centre for Medical Sciences, University of Trento, 38122, Trento, Italy
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3
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Okenov A, Nezlobinsky T, Zeppenfeld K, Vandersickel N, Panfilov AV. Computer based method for identification of fibrotic scars from electrograms and local activation times on the epi- and endocardial surfaces of the ventricles. PLoS One 2024; 19:e0300978. [PMID: 38625849 PMCID: PMC11020530 DOI: 10.1371/journal.pone.0300978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 03/07/2024] [Indexed: 04/18/2024] Open
Abstract
Cardiac fibrosis stands as one of the most critical conditions leading to lethal cardiac arrhythmias. Identifying the precise location of cardiac fibrosis is crucial for planning clinical interventions in patients with various forms of ventricular and atrial arrhythmias. As fibrosis impedes and alters the path of electrical waves, detecting fibrosis in the heart can be achieved through analyzing electrical signals recorded from its surface. In current clinical practices, it has become feasible to record electrical activity from both the endocardial and epicardial surfaces of the heart. This paper presents a computational method for reconstructing 3D fibrosis using unipolar electrograms obtained from both surfaces of the ventricles. The proposed method calculates the percentage of fibrosis in various ventricular segments by analyzing the local activation times and peak-to-peak amplitudes of the electrograms. Initially, the method was tested using simulated data representing idealized fibrosis in a heart segment; subsequently, it was validated in the left ventricle with fibrosis obtained from a patient with nonischemic cardiomyopathy. The method successfully determined the location and extent of fibrosis in 204 segments of the left ventricle model with an average error of 0.0±4.3% (N = 204). Moreover, the method effectively detected fibrotic scars in the mid-myocardial region, a region known to present challenges in accurate detection using electrogram amplitude as the primary criterion.
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Affiliation(s)
- Arstanbek Okenov
- Department of Physics and Astronomy, Ghent University, Gent, Belgium
| | - Timur Nezlobinsky
- Department of Physics and Astronomy, Ghent University, Gent, Belgium
| | - Katja Zeppenfeld
- Department of Cardiology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Nele Vandersickel
- Department of Physics and Astronomy, Ghent University, Gent, Belgium
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4
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Lootens S, Janssens I, Van Den Abeele R, Wülfers EM, Bezerra AS, Verstraeten B, Hendrickx S, Okenov A, Nezlobinsky T, Panfilov AV, Vandersickel N. Directed Graph Mapping exceeds Phase Mapping for the detection of simulated 2D meandering rotors in fibrotic tissue with added noise. Comput Biol Med 2024; 171:108138. [PMID: 38401451 DOI: 10.1016/j.compbiomed.2024.108138] [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: 10/27/2023] [Revised: 02/09/2024] [Accepted: 02/12/2024] [Indexed: 02/26/2024]
Abstract
Cardiac arrhythmias such as atrial fibrillation (AF) are recognised to be associated with re-entry or rotors. A rotor is a wave of excitation in the cardiac tissue that wraps around its refractory tail, causing faster-than-normal periodic excitation. The detection of rotor centres is of crucial importance in guiding ablation strategies for the treatment of arrhythmia. The most popular technique for detecting rotor centres is Phase Mapping (PM), which detects phase singularities derived from the phase of a signal. This method has been proven to be prone to errors, especially in regimes of fibrotic tissue and temporal noise. Recently, a novel technique called Directed Graph Mapping (DGM) was developed to detect rotational activity such as rotors by creating a network of excitation. This research aims to compare the performance of advanced PM techniques versus DGM for the detection of rotors using 64 simulated 2D meandering rotors in the presence of various levels of fibrotic tissue and temporal noise. Four strategies were employed to compare the performances of PM and DGM. These included a visual analysis, a comparison of F2-scores and distance distributions, and calculating p-values using the mid-p McNemar test. Results indicate that in the case of low meandering, fibrosis and noise, PM and DGM yield excellent results and are comparable. However, in the case of high meandering, fibrosis and noise, PM is undeniably prone to errors, mainly in the form of an excess of false positives, resulting in low precision. In contrast, DGM is more robust against these factors as F2-scores remain high, yielding F2≥0.931 as opposed to the best PM F2≥0.635 across all 64 simulations.
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Affiliation(s)
| | - Iris Janssens
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | | | - Eike M Wülfers
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | | | - Bjorn Verstraeten
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Sander Hendrickx
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Arstanbek Okenov
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Timur Nezlobinsky
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Alexander V Panfilov
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium; World-Class Research Center "Digital Biodesign and personalised healthcare", Sechenov University, Moscow 119991, Russia; Laboratory of Computational Biology and Medicine, Ural Federal University, Ekaterinburg 620002, Russia
| | - Nele Vandersickel
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
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5
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Sridhar S, Clayton RH. Fibroblast mediated dynamics in diffusively uncoupled myocytes: a simulation study using 2-cell motifs. Sci Rep 2024; 14:4493. [PMID: 38396245 PMCID: PMC10891142 DOI: 10.1038/s41598-024-54564-1] [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: 10/23/2023] [Accepted: 02/14/2024] [Indexed: 02/25/2024] Open
Abstract
In healthy hearts myocytes are typically coupled to nearest neighbours through gap junctions. Under pathological conditions such as fibrosis, or in scar tissue, or across ablation lines myocytes can uncouple from their neighbours. Electrical conduction may still occur via fibroblasts that not only couple proximal myocytes but can also couple otherwise unconnected regions. We hypothesise that such coupling can alter conduction between myocytes via introduction of delays or by initiation of premature stimuli that can potentially result in reentry or conduction blocks. To test this hypothesis we have developed several 2-cell motifs and investigated the effect of fibroblast mediated electrical coupling between uncoupled myocytes. We have identified various regimes of myocyte behaviour that depend on the strength of gap-junctional conductance, connection topology, and parameters of the myocyte and fibroblast models. These motifs are useful in developing a mechanistic understanding of long-distance coupling on myocyte dynamics and enable the characterisation of interaction between different features such as myocyte and fibroblast properties, coupling strengths and pacing period. They are computationally inexpensive and allow for incorporation of spatial effects such as conduction velocity. They provide a framework for constructing scar tissue boundaries and enable linking of cellular level interactions with scar induced arrhythmia.
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Affiliation(s)
- S Sridhar
- Department of Computer Science, University of Sheffield, Sheffield, UK.
| | - Richard H Clayton
- Department of Computer Science, University of Sheffield, Sheffield, UK
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6
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Reisqs JB, Moreau A, Sleiman Y, Boutjdir M, Richard S, Chevalier P. Arrhythmogenic cardiomyopathy as a myogenic disease: highlights from cardiomyocytes derived from human induced pluripotent stem cells. Front Physiol 2023; 14:1191965. [PMID: 37250123 PMCID: PMC10210147 DOI: 10.3389/fphys.2023.1191965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/02/2023] [Indexed: 05/31/2023] Open
Abstract
Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiomyopathy characterized by the replacement of myocardium by fibro-fatty infiltration and cardiomyocyte loss. ACM predisposes to a high risk for ventricular arrhythmias. ACM has initially been defined as a desmosomal disease because most of the known variants causing the disease concern genes encoding desmosomal proteins. Studying this pathology is complex, in particular because human samples are rare and, when available, reflect the most advanced stages of the disease. Usual cellular and animal models cannot reproduce all the hallmarks of human pathology. In the last decade, human-induced pluripotent stem cells (hiPSC) have been proposed as an innovative human cellular model. The differentiation of hiPSCs into cardiomyocytes (hiPSC-CM) is now well-controlled and widely used in many laboratories. This hiPSC-CM model recapitulates critical features of the pathology and enables a cardiomyocyte-centered comprehensive approach to the disease and the screening of anti-arrhythmic drugs (AAD) prescribed sometimes empirically to the patient. In this regard, this model provides unique opportunities to explore and develop new therapeutic approaches. The use of hiPSC-CMs will undoubtedly help the development of precision medicine to better cure patients suffering from ACM. This review aims to summarize the recent advances allowing the use of hiPSCs in the ACM context.
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Affiliation(s)
- J. B. Reisqs
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States
| | - A. Moreau
- Université de Montpellier, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, PhyMedExp, Montpellier, France
| | - Y. Sleiman
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States
| | - M. Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States
- Department of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Health Sciences University, NY, United States
- Department of Medicine, New York University School of Medicine, NY, United States
| | - S. Richard
- Université de Montpellier, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, PhyMedExp, Montpellier, France
| | - P. Chevalier
- Neuromyogene Institute, Claude Bernard University, Lyon 1, Villeurbanne, France
- Service de Rythmologie, Hospices Civils de Lyon, Lyon, France
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7
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Lawson BA, dos Santos RW, Turner IW, Bueno-Orovio A, Burrage P, Burrage K. Homogenisation for the monodomain model in the presence of microscopic fibrotic structures. COMMUNICATIONS IN NONLINEAR SCIENCE & NUMERICAL SIMULATION 2023; 116:None. [PMID: 37113591 PMCID: PMC10124103 DOI: 10.1016/j.cnsns.2022.106794] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 05/06/2022] [Accepted: 08/04/2022] [Indexed: 06/08/2023]
Abstract
Computational models in cardiac electrophysiology are notorious for long runtimes, restricting the numbers of nodes and mesh elements in the numerical discretisations used for their solution. This makes it particularly challenging to incorporate structural heterogeneities on small spatial scales, preventing a full understanding of the critical arrhythmogenic effects of conditions such as cardiac fibrosis. In this work, we explore the technique of homogenisation by volume averaging for the inclusion of non-conductive micro-structures into larger-scale cardiac meshes with minor computational overhead. Importantly, our approach is not restricted to periodic patterns, enabling homogenised models to represent, for example, the intricate patterns of collagen deposition present in different types of fibrosis. We first highlight the importance of appropriate boundary condition choice for the closure problems that define the parameters of homogenised models. Then, we demonstrate the technique's ability to correctly upscale the effects of fibrotic patterns with a spatial resolution of 10 µm into much larger numerical mesh sizes of 100- 250 µm . The homogenised models using these coarser meshes correctly predict critical pro-arrhythmic effects of fibrosis, including slowed conduction, source/sink mismatch, and stabilisation of re-entrant activation patterns. As such, this approach to homogenisation represents a significant step towards whole organ simulations that unravel the effects of microscopic cardiac tissue heterogeneities.
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Affiliation(s)
- Brodie A.J. Lawson
- Centre for Data Science, Queensland University of Technology, 2 George Street, Brisbane, 4000, Queensland, Australia
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, Queensland University of Technology, 2 George Street, Brisbane, 4000, Queensland, Australia
- School of Mathematical Sciences, Queensland University of Technology, 2 George Street, Brisbane, 4000, Queensland, Australia
| | - Rodrigo Weber dos Santos
- Graduate Program on Computational Modelling, Universidade de Federal de Juiz de Fora, Rua Jose Lourenco Kelmer s/n, Juiz de Fora, 36036-900, Minas Gerais, Brazil
| | - Ian W. Turner
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, Queensland University of Technology, 2 George Street, Brisbane, 4000, Queensland, Australia
- School of Mathematical Sciences, Queensland University of Technology, 2 George Street, Brisbane, 4000, Queensland, Australia
| | - Alfonso Bueno-Orovio
- Department of Computer Science, University of Oxford, Parks Rd, Oxford, OX1 3QD, Oxfordshire, United Kingdom
| | - Pamela Burrage
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, Queensland University of Technology, 2 George Street, Brisbane, 4000, Queensland, Australia
- School of Mathematical Sciences, Queensland University of Technology, 2 George Street, Brisbane, 4000, Queensland, Australia
| | - Kevin Burrage
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, Queensland University of Technology, 2 George Street, Brisbane, 4000, Queensland, Australia
- School of Mathematical Sciences, Queensland University of Technology, 2 George Street, Brisbane, 4000, Queensland, Australia
- Department of Computer Science, University of Oxford, Parks Rd, Oxford, OX1 3QD, Oxfordshire, United Kingdom
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8
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Young WJ, Lahrouchi N, Isaacs A, Duong T, Foco L, Ahmed F, Brody JA, Salman R, Noordam R, Benjamins JW, Haessler J, Lyytikäinen LP, Repetto L, Concas MP, van den Berg ME, Weiss S, Baldassari AR, Bartz TM, Cook JP, Evans DS, Freudling R, Hines O, Isaksen JL, Lin H, Mei H, Moscati A, Müller-Nurasyid M, Nursyifa C, Qian Y, Richmond A, Roselli C, Ryan KA, Tarazona-Santos E, Thériault S, van Duijvenboden S, Warren HR, Yao J, Raza D, Aeschbacher S, Ahlberg G, Alonso A, Andreasen L, Bis JC, Boerwinkle E, Campbell A, Catamo E, Cocca M, Cutler MJ, Darbar D, De Grandi A, De Luca A, Ding J, Ellervik C, Ellinor PT, Felix SB, Froguel P, Fuchsberger C, Gögele M, Graff C, Graff M, Guo X, Hansen T, Heckbert SR, Huang PL, Huikuri HV, Hutri-Kähönen N, Ikram MA, Jackson RD, Junttila J, Kavousi M, Kors JA, Leal TP, Lemaitre RN, Lin HJ, Lind L, Linneberg A, Liu S, MacFarlane PW, Mangino M, Meitinger T, Mezzavilla M, Mishra PP, Mitchell RN, Mononen N, Montasser ME, Morrison AC, Nauck M, Nauffal V, Navarro P, Nikus K, Pare G, Patton KK, Pelliccione G, Pittman A, Porteous DJ, Pramstaller PP, Preuss MH, Raitakari OT, Reiner AP, Ribeiro ALP, Rice KM, Risch L, Schlessinger D, Schotten U, Schurmann C, Shen X, Shoemaker MB, Sinagra G, Sinner MF, Soliman EZ, Stoll M, Strauch K, Tarasov K, Taylor KD, Tinker A, Trompet S, Uitterlinden A, Völker U, Völzke H, Waldenberger M, Weng LC, Whitsel EA, Wilson JG, Avery CL, Conen D, Correa A, Cucca F, Dörr M, Gharib SA, Girotto G, Grarup N, Hayward C, Jamshidi Y, Järvelin MR, Jukema JW, Kääb S, Kähönen M, Kanters JK, Kooperberg C, Lehtimäki T, Lima-Costa MF, Liu Y, Loos RJF, Lubitz SA, Mook-Kanamori DO, Morris AP, O'Connell JR, Olesen MS, Orini M, Padmanabhan S, Pattaro C, Peters A, Psaty BM, Rotter JI, Stricker B, van der Harst P, van Duijn CM, Verweij N, Wilson JF, Arking DE, Ramirez J, Lambiase PD, Sotoodehnia N, Mifsud B, Newton-Cheh C, Munroe PB. Genetic analyses of the electrocardiographic QT interval and its components identify additional loci and pathways. Nat Commun 2022; 13:5144. [PMID: 36050321 PMCID: PMC9436946 DOI: 10.1038/s41467-022-32821-z] [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: 11/19/2021] [Accepted: 08/17/2022] [Indexed: 11/10/2022] Open
Abstract
The QT interval is an electrocardiographic measure representing the sum of ventricular depolarization and repolarization, estimated by QRS duration and JT interval, respectively. QT interval abnormalities are associated with potentially fatal ventricular arrhythmia. Using genome-wide multi-ancestry analyses (>250,000 individuals) we identify 177, 156 and 121 independent loci for QT, JT and QRS, respectively, including a male-specific X-chromosome locus. Using gene-based rare-variant methods, we identify associations with Mendelian disease genes. Enrichments are observed in established pathways for QT and JT, and previously unreported genes indicated in insulin-receptor signalling and cardiac energy metabolism. In contrast for QRS, connective tissue components and processes for cell growth and extracellular matrix interactions are significantly enriched. We demonstrate polygenic risk score associations with atrial fibrillation, conduction disease and sudden cardiac death. Prioritization of druggable genes highlight potential therapeutic targets for arrhythmia. Together, these results substantially advance our understanding of the genetic architecture of ventricular depolarization and repolarization.
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Affiliation(s)
- William J Young
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK
- Barts Heart Centre, St Bartholomew's Hospital, Barts Health NHS trust, London, UK
| | - Najim Lahrouchi
- Amsterdam UMC, University of Amsterdam, Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Cardiovascular Research Center, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Aaron Isaacs
- Deptartment of Physiology, Cardiovascular Research Institute Maastricht CARIM, Maastricht University, Maastricht, The Netherlands
- Maastricht Center for Systems Biology MaCSBio, Maastricht University, Maastricht, The Netherlands
| | - ThuyVy Duong
- McKusick-Nathans Institute, Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Luisa Foco
- Eurac Research, Institute for Biomedicine affiliated with the University of Lübeck, Bolzano, Italy
| | - Farah Ahmed
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK
| | - Jennifer A Brody
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Reem Salman
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK
| | - Raymond Noordam
- Department of Internal Medicine, section of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Jan-Walter Benjamins
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
| | - Jeffrey Haessler
- Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Leo-Pekka Lyytikäinen
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere, Finland
- Department of Clinical Chemistry, Finnish Cardiovascular Research Center - Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Linda Repetto
- Centre for Global Health Research, Usher Institute, University of Edinburgh, Edinburgh, Scotland
| | - Maria Pina Concas
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Marten E van den Berg
- Department of Epidemiology, Erasmus MC - University Medical Center, Rotterdam, The Netherlands
| | - Stefan Weiss
- DZHK German Centre for Cardiovascular Research; partner site Greifswald, Greifswald, Germany
- Interfaculty Institute for Genetics and Functional Genomics; Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Antoine R Baldassari
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Traci M Bartz
- Cardiovascular Health Research Unit, Departments of Biostatistics and Medicine, University of Washington, Seattle, WA, USA
| | - James P Cook
- Department of Health Data Science, University of Liverpool, Liverpool, UK
| | - Daniel S Evans
- California Pacific Medical Center, Research Institute, San Francisco, CA, USA
| | - Rebecca Freudling
- Department of Cardiology, University Hospital, LMU Munich, Munich, Germany
- Institute of Genetic Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
| | - Oliver Hines
- Genetics Research Centre, St George's University of London, London, UK
- Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK
| | - Jonas L Isaksen
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Honghuang Lin
- National Heart Lung and Blood Institute's and Boston University's Framingham Heart Study, Framingham, MA, USA
- Section of Computational Biomedicine, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Hao Mei
- Department of Data Science, University of Mississippi Medical Center, Jackson, USA
| | - Arden Moscati
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Martina Müller-Nurasyid
- Institute of Genetic Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- IBE, Faculty of Medicine, LMU Munich, Munich, Germany
- Institute of Medical Biostatistics, Epidemiology and Informatics IMBEI, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Casia Nursyifa
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yong Qian
- Translational Gerontology Branch, National Institute on Aging, National Institute of Health, Baltimore, US
| | - Anne Richmond
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Carolina Roselli
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
- Cardiovascular Disease Initiative, Broad Institute, Cambridge, MA, USA
| | - Kathleen A Ryan
- Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, Baltimore, MD, USA
- Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Eduardo Tarazona-Santos
- Department of Genetics, Ecology and Evolution, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte/Minas Gerais, Brazil
| | - Sébastien Thériault
- Population Health Research Institute, McMaster University, Hamilton, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Université Laval, Quebec, Canada
| | - Stefan van Duijvenboden
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK
- Institute of Cardiovascular Sciences, University of College London, London, UK
| | - Helen R Warren
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK
- NIHR Barts Cardiovascular Biomedical Research Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Jie Yao
- Institute for Translational Genomics and Population Sciences/The Lundquist Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Dania Raza
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK
- Brighton and Sussex Medical School, Brighton, UK
| | - Stefanie Aeschbacher
- Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Gustav Ahlberg
- Laboratory for Molecular Cardiology, The Heart Centre, Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Alvaro Alonso
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Laura Andreasen
- Laboratory for Molecular Cardiology, The Heart Centre, Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Joshua C Bis
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Eric Boerwinkle
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Archie Campbell
- Usher Institute, University of Edinburgh, Nine, Edinburgh Bioquarter, 9 Little France Road, Edinburgh, UK
- Health Data Research UK, University of Edinburgh, Nine, Edinburgh Bioquarter, 9 Little France Road, Edinburgh, UK
- Centre for Genomic and Experimental Medicine, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Eulalia Catamo
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Massimiliano Cocca
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Michael J Cutler
- Intermountain Heart Institute, Intermountain Medical Center, Murray, UT, USA
| | - Dawood Darbar
- Department of Medicine, University of Illinois at Chicago, Chicago, USA
| | - Alessandro De Grandi
- Eurac Research, Institute for Biomedicine affiliated with the University of Lübeck, Bolzano, Italy
| | - Antonio De Luca
- Cardiothoracovascular Department, ASUGI, University of Trieste, Trieste, Italy
| | - Jun Ding
- Translational Gerontology Branch, National Institute on Aging, National Institute of Health, Baltimore, US
| | - Christina Ellervik
- Department of Data and Data Support, Region Zealand, 4180, Sorø, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
- Department of Laboratory Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Patrick T Ellinor
- Cardiovascular Disease Initiative, Broad Institute, Cambridge, MA, USA
- Demoulas Center for Cardiac Arrhythmias and Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Stephan B Felix
- DZHK German Centre for Cardiovascular Research; partner site Greifswald, Greifswald, Germany
- Department of Internal Medicine B - Cardiology, Pneumology, Infectious Diseases, Intensive Care Medicine; University Medicine Greifswald, Greifswald, Germany
| | - Philippe Froguel
- Department of Epidemiology and Biostatistics, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK
- University of Lille Nord de France, Lille, France
- CNRS UMR8199, Institut Pasteur de Lille, Lille, France
| | - Christian Fuchsberger
- Eurac Research, Institute for Biomedicine affiliated with the University of Lübeck, Bolzano, Italy
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, USA
- Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, USA
| | - Martin Gögele
- Eurac Research, Institute for Biomedicine affiliated with the University of Lübeck, Bolzano, Italy
| | - Claus Graff
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Mariaelisa Graff
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Xiuqing Guo
- Institute for Translational Genomics and Population Sciences/The Lundquist Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Pediatrics/Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Pediatrics/David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Torben Hansen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Susan R Heckbert
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Epidemiology/University of Washington, Seattle, WA, USA
| | - Paul L Huang
- Cardiology Division and Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Heikki V Huikuri
- Research Unit of Internal Medicine, Medical Research Center Oulu, University of Oulu and University Hospital of Oulu, Oulu, Finland
| | - Nina Hutri-Kähönen
- Department of Pediatrics, Tampere University Hospital, Tampere, Finland
- Department of Pediatrics, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Tampere Centre for Skills Training and Simulation, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - M Arfan Ikram
- Department of Epidemiology, Erasmus MC - University Medical Center, Rotterdam, The Netherlands
| | - Rebecca D Jackson
- Center for Clinical and Translational Science, Ohio State Medical Center, Columbus, OH, USA
| | - Juhani Junttila
- Research Unit of Internal Medicine, Medical Research Center Oulu, University of Oulu and University Hospital of Oulu, Oulu, Finland
| | - Maryam Kavousi
- Department of Epidemiology, Erasmus MC - University Medical Center, Rotterdam, The Netherlands
| | - Jan A Kors
- Department of Medical Informatics, Erasmus University Medical Center, Rotterdam, NL, The Netherlands
| | - Thiago P Leal
- Department of Genetics, Ecology and Evolution, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte/Minas Gerais, Brazil
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Rozenn N Lemaitre
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Henry J Lin
- Institute for Translational Genomics and Population Sciences/The Lundquist Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Pediatrics/Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Pediatrics/David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Lars Lind
- Deptartment of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Allan Linneberg
- Center for Clinical Research and Prevention, Bispebjerg and Frederiksberg Hospital, Frederiksberg, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Simin Liu
- Center for Global Cardiometabolic Health, Departments of Epidemiology, Medicine and Surgery, Brown University, Providence, USA
| | - Peter W MacFarlane
- Institute of Health and Wellbeing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Massimo Mangino
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
- NIHR Biomedical Research Centre at Guy's and St Thomas' Foundation Trust, London, UK
| | - Thomas Meitinger
- Institute of Genetic Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- DZHK (German Centre for Cardiovascular Research, partner site: Munich Heart Alliance, Munich, Germany
| | - Massimo Mezzavilla
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Pashupati P Mishra
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere, Finland
- Department of Clinical Chemistry, Finnish Cardiovascular Research Center - Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Rebecca N Mitchell
- McKusick-Nathans Institute, Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nina Mononen
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere, Finland
- Department of Clinical Chemistry, Finnish Cardiovascular Research Center - Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - May E Montasser
- Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, Baltimore, MD, USA
- Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alanna C Morrison
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Matthias Nauck
- DZHK German Centre for Cardiovascular Research; partner site Greifswald, Greifswald, Germany
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Victor Nauffal
- Cardiovascular Disease Initiative, Broad Institute, Cambridge, MA, USA
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Pau Navarro
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | - Kjell Nikus
- Department of Cardiology, Heart Center, Tampere University Hospital, Tampere, Finland
- Department of Cardiology, Finnish Cardiovascular Research Center - Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Guillaume Pare
- Population Health Research Institute, McMaster University, Hamilton, Canada
| | - Kristen K Patton
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Giulia Pelliccione
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Alan Pittman
- Genetics Research Centre, St George's University of London, London, UK
| | - David J Porteous
- Centre for Genomic and Experimental Medicine, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
- Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK
| | - Peter P Pramstaller
- Eurac Research, Institute for Biomedicine affiliated with the University of Lübeck, Bolzano, Italy
- Department of Neurology, University of Lübeck, Lübeck, Germany
| | - Michael H Preuss
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Olli T Raitakari
- Centre for Population Health Research, University of Turku and Turku University Hospital, Turku, Finland
- Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku, Finland
- Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Turku, Finland
| | - Alexander P Reiner
- Department of Epidemiology/University of Washington, Seattle, WA, USA
- Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
| | - Antonio Luiz P Ribeiro
- Department of Internal Medicine, Faculdade de Medicina, Universidade Federal de Minas Gerais, Brazil, Belo Horizonte, Minas Gerais, Brazil
- Cardiology Service and Telehealth Center, Hospital das Clínicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil, Belo Horizonte, Minas Gerais, Brazil
| | - Kenneth M Rice
- Department of Biostatistics, University of Washington, Seattle, WA, USA
| | - Lorenz Risch
- Labormedizinisches zentrum Dr. Risch, Vaduz, Liechtenstein
- Faculty of Medical Sciences, Private University in the Principality of Liechtenstein, Triesen, Liechtenstein
- Center of Laboratory Medicine, University Institute of Clinical Chemistry, University of Bern, Inselspital, Bern, Switzerland
| | - David Schlessinger
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institute of Health, Baltimore, US
| | - Ulrich Schotten
- Deptartment of Physiology, Cardiovascular Research Institute Maastricht CARIM, Maastricht University, Maastricht, The Netherlands
| | - Claudia Schurmann
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Digital Health Center, Hasso Plattner Institute, University of Potsdam, Potsdam, Germany
- Hasso Plattner Institute for Digital Health at Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Xia Shen
- Centre for Global Health Research, Usher Institute, University of Edinburgh, Edinburgh, Scotland
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Greater Bay Area Institute of Precision Medicine Guangzhou, Fudan University, Nansha District, Guangzhou, China
| | - M Benjamin Shoemaker
- Department of Medicine, Division of Cardiovascular Medicine, Arrhythmia Section, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Gianfranco Sinagra
- Cardiothoracovascular Department, ASUGI, University of Trieste, Trieste, Italy
| | - Moritz F Sinner
- Department of Cardiology, University Hospital, LMU Munich, Munich, Germany
- DZHK (German Centre for Cardiovascular Research, partner site: Munich Heart Alliance, Munich, Germany
| | - Elsayed Z Soliman
- Epidemiological Cardiology Research Center EPICARE, Wake Forest School of Medicine, Winston Salem, USA
| | - Monika Stoll
- Maastricht Center for Systems Biology MaCSBio, Maastricht University, Maastricht, The Netherlands
- Dept. of Biochemistry, Cardiovascular Research Institute Maastricht CARIM, Maastricht University, Maastricht, NL, The Netherlands
- Institute of Human Genetics, Genetic Epidemiology, University of Muenster, Muenster, Germany
| | - Konstantin Strauch
- Institute of Genetic Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- IBE, Faculty of Medicine, LMU Munich, Munich, Germany
- Institute of Medical Biostatistics, Epidemiology and Informatics IMBEI, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Kirill Tarasov
- Laboratory of Cardiovascular Sciences, National Institute on Aging, National Institute of Health, Baltimore, US
| | - Kent D Taylor
- Institute for Translational Genomics and Population Sciences/The Lundquist Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Pediatrics/Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Pediatrics/David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Andrew Tinker
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK
- NIHR Barts Cardiovascular Biomedical Research Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Stella Trompet
- Department of Internal Medicine, section of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Uwe Völker
- DZHK German Centre for Cardiovascular Research; partner site Greifswald, Greifswald, Germany
- Interfaculty Institute for Genetics and Functional Genomics; Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Henry Völzke
- DZHK German Centre for Cardiovascular Research; partner site Greifswald, Greifswald, Germany
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Melanie Waldenberger
- DZHK (German Centre for Cardiovascular Research, partner site: Munich Heart Alliance, Munich, Germany
- Research Unit Molecular Epidemiology, Institute of Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
| | - Lu-Chen Weng
- Cardiovascular Disease Initiative, Broad Institute, Cambridge, MA, USA
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Eric A Whitsel
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, USA
- Department of Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - James G Wilson
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, USA
- Department of Cardiology, Beth Israel Deaconess Medical Center, Boston, USA
| | - Christy L Avery
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - David Conen
- Population Health Research Institute, McMaster University, Hamilton, Canada
| | - Adolfo Correa
- Departments of Medicine, Pediatrics and Population Health Science, University of Mississippi Medical Center, Jackson, USA
| | - Francesco Cucca
- Institute of Genetic and Biomedical Rsearch, Italian National Research Council, Monserrato, Italy
| | - Marcus Dörr
- DZHK German Centre for Cardiovascular Research; partner site Greifswald, Greifswald, Germany
- Department of Internal Medicine B - Cardiology, Pneumology, Infectious Diseases, Intensive Care Medicine; University Medicine Greifswald, Greifswald, Germany
| | - Sina A Gharib
- Center for Lung Biology, Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, WA, USA
| | - Giorgia Girotto
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
- Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Niels Grarup
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Caroline Hayward
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Yalda Jamshidi
- Genetics Research Centre, St George's University of London, London, UK
| | - Marjo-Riitta Järvelin
- Center for Life Course Health Research, Faculty of Medicine, University of Oulu, Oulu, Finland
- Unit of Primary Health Care, Oulu University Hospital, Oulu, Finland
- Department of Epidemiology and Biostatistics, MRC PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK
- Department of Life Sciences, College of Health and Life Sciences, Brunel University London, London, UK
| | - J Wouter Jukema
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
- Netherlands Heart Institute, Utrecht, The Netherlands
| | - Stefan Kääb
- Department of Cardiology, University Hospital, LMU Munich, Munich, Germany
- DZHK (German Centre for Cardiovascular Research, partner site: Munich Heart Alliance, Munich, Germany
| | - Mika Kähönen
- Department of Clinical Physiology, Tampere University Hospital, Tampere, Finland
- Department of Clinical Physiology, Finnish Cardiovascular Research Center - Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Jørgen K Kanters
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charles Kooperberg
- Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Terho Lehtimäki
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere, Finland
- Department of Clinical Chemistry, Finnish Cardiovascular Research Center - Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | | | - Yongmei Liu
- Department of Medicine, Duke University, Durham, NC, USA
| | - Ruth J F Loos
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Steven A Lubitz
- Cardiovascular Disease Initiative, Broad Institute, Cambridge, MA, USA
- Demoulas Center for Cardiac Arrhythmias and Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Dennis O Mook-Kanamori
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, The Netherlands
| | - Andrew P Morris
- Department of Health Data Science, University of Liverpool, Liverpool, UK
- Centre for Genetics and Genomics Versus Arthritis, Centre for Musculoskeletal Research, The University of Manchester, Manchester, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Jeffrey R O'Connell
- Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, Baltimore, MD, USA
- Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Michele Orini
- Barts Heart Centre, St Bartholomew's Hospital, Barts Health NHS trust, London, UK
- Institute of Cardiovascular Sciences, University of College London, London, UK
| | - Sandosh Padmanabhan
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Cristian Pattaro
- Eurac Research, Institute for Biomedicine affiliated with the University of Lübeck, Bolzano, Italy
| | - Annette Peters
- Institute of Genetic Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- DZHK (German Centre for Cardiovascular Research, partner site: Munich Heart Alliance, Munich, Germany
| | - Bruce M Psaty
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Epidemiology/University of Washington, Seattle, WA, USA
- Health Systems and Population Health, University of Washington, Seattle, WA, USA
| | - Jerome I Rotter
- Institute for Translational Genomics and Population Sciences/The Lundquist Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Pediatrics/Harbor-UCLA Medical Center, Torrance, CA, USA
- Departments of Pediatrics and Human Genetics/David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Bruno Stricker
- Department of Epidemiology, Erasmus MC - University Medical Center, Rotterdam, The Netherlands
| | - Pim van der Harst
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
- Department of Cardiology, Heart and Lung Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Cornelia M van Duijn
- Nuffield Department of Population Health, University of Oxford, Oxford, UK
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Niek Verweij
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
| | - James F Wilson
- Centre for Global Health Research, Usher Institute, University of Edinburgh, Edinburgh, Scotland
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | - Dan E Arking
- McKusick-Nathans Institute, Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Julia Ramirez
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK
- Institute of Cardiovascular Sciences, University of College London, London, UK
| | - Pier D Lambiase
- Barts Heart Centre, St Bartholomew's Hospital, Barts Health NHS trust, London, UK
- Institute of Cardiovascular Sciences, University of College London, London, UK
| | - Nona Sotoodehnia
- Cardiovascular Health Research Unit, Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Borbala Mifsud
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK
- Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Christopher Newton-Cheh
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA, USA.
- Cardiovascular Research Center, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.
| | - Patricia B Munroe
- William Harvey Research Institute, Clinical Pharmacology, Queen Mary University of London, London, UK.
- NIHR Barts Cardiovascular Biomedical Research Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
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9
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Balaban G, Halliday BP, Hammersley D, Rinaldi CA, Prasad SK, Bishop MJ, Lamata P. Left ventricular shape predicts arrhythmic risk in fibrotic dilated cardiomyopathy. Europace 2022; 24:1137-1147. [PMID: 34907426 PMCID: PMC9301973 DOI: 10.1093/europace/euab306] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 11/16/2021] [Indexed: 02/07/2023] Open
Abstract
AIMS Remodelling of the left ventricular (LV) shape is one of the hallmarks of non-ischaemic dilated cardiomyopathy (DCM) and may contribute to ventricular arrhythmias and sudden cardiac death. We sought to investigate a novel three dimensional (3D) shape analysis approach to quantify LV remodelling for arrhythmia prediction in DCM. METHODS AND RESULTS We created 3D LV shape models from end-diastolic cardiac magnetic resonance images of 156 patients with DCM and late gadolinium enhancement (LGE). Using the shape models, principle component analysis, and Cox-Lasso regression, we derived a prognostic LV arrhythmic shape (LVAS) score which identified patients who reached a composite arrhythmic endpoint of sudden cardiac death, aborted sudden cardiac death, and sustained ventricular tachycardia. We also extracted geometrical metrics to look for potential prognostic markers. During a follow-up period of up to 16 years (median 7.7, interquartile range: 3.9), 25 patients met the arrhythmic endpoint. The optimally prognostic LV shape for predicting the time-to arrhythmic event was a paraboloidal longitudinal profile, with a relatively wide base. The corresponding LVAS was associated with arrhythmic events in univariate Cox regression (hazard ratio = 2.0 per quartile; 95% confidence interval: 1.3-2.9), in univariate Cox regression with propensity score adjustment, and in three multivariate models; with LV ejection fraction, New York Heart Association Class III/IV (Model 1), implantable cardioverter-defibrillator receipt (Model 2), and cardiac resynchronization therapy (Model 3). CONCLUSION Biomarkers of LV shape remodelling in DCM can help to identify the patients at greatest risk of lethal ventricular arrhythmias.
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Affiliation(s)
- Gabriel Balaban
- Department of Biomedical Engineering, School of Biomedical & Imaging Sciences, King’s College London, 249 Westminster Bridge Road, SE1 7EH London, UK
- Biomedical Informatics Group, Department of Informatics, University of Oslo, Oslo, Norway
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
- PharmaTox Strategic Research Initiative, Deparment of Pharmacy, University of Oslo, 0373 Oslo, Norway
| | - Brian P Halliday
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK
| | - Daniel Hammersley
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK
| | - Christopher A Rinaldi
- Department of Biomedical Engineering, School of Biomedical & Imaging Sciences, King’s College London, 249 Westminster Bridge Road, SE1 7EH London, UK
- Department of Cardiology, St Thomas’ Hospital, London, UK
| | - Sanjay K Prasad
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK
| | - Martin J Bishop
- Department of Biomedical Engineering, School of Biomedical & Imaging Sciences, King’s College London, 249 Westminster Bridge Road, SE1 7EH London, UK
| | - Pablo Lamata
- Department of Biomedical Engineering, School of Biomedical & Imaging Sciences, King’s College London, 249 Westminster Bridge Road, SE1 7EH London, UK
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10
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Farquhar ME, Burrage K, Weber Dos Santos R, Bueno-Orovio A, Lawson BA. Graph-based homogenisation for modelling cardiac fibrosis. JOURNAL OF COMPUTATIONAL PHYSICS 2022; 459:None. [PMID: 35959500 PMCID: PMC9352598 DOI: 10.1016/j.jcp.2022.111126] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/15/2022] [Accepted: 03/02/2022] [Indexed: 05/02/2023]
Abstract
Fibrosis, the excess of extracellular matrix, can affect, and even block, propagation of action potential in cardiac tissue. This can result in deleterious effects on heart function, but the nature and severity of these effects depend strongly on the localisation of fibrosis and its by-products in cardiac tissue, such as collagen scar formation. Computer simulation is an important means of understanding the complex effects of fibrosis on activation patterns in the heart, but concerns of computational cost place restrictions on the spatial resolution of these simulations. In this work, we present a novel numerical homogenisation technique that uses both Eikonal and graph approaches to allow fine-scale heterogeneities in conductivity to be incorporated into a coarser mesh. Homogenisation achieves this by deriving effective conductivity tensors so that a coarser mesh can then be used for numerical simulation. By taking a graph-based approach, our homogenisation technique functions naturally on irregular grids and does not rely upon any assumptions of periodicity, even implicitly. We present results of action potential propagation through fibrotic tissue in two dimensions that show the graph-based homogenisation technique is an accurate and effective way to capture fine-scale domain information on coarser meshes in the context of sharp-fronted travelling waves of activation. As test problems, we consider excitation propagation in tissue with diffuse fibrosis and through a tunnel-like structure designed to test homogenisation, interaction of an excitation wave with a scar region, and functional re-entry.
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Affiliation(s)
- Megan E. Farquhar
- Australian Research Council Centre of Excellence for Mathematical and Statistical Frontiers, School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia
| | - Kevin Burrage
- Australian Research Council Centre of Excellence for Mathematical and Statistical Frontiers, School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia
- Department of Computer Science, Oxford University, Oxford, United Kingdom
| | - Rodrigo Weber Dos Santos
- Department of Computer Science and Program on Computational Modeling, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
| | | | - Brodie A.J. Lawson
- Australian Research Council Centre of Excellence for Mathematical and Statistical Frontiers, School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia
- Centre for Data Science, Queensland University of Technology, Brisbane, Australia
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11
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Biasi N, Seghetti P, Tognetti A. Diffuse fibrosis and repolarization disorders explain ventricular arrhythmias in Brugada syndrome: a computational study. Sci Rep 2022; 12:8530. [PMID: 35595775 PMCID: PMC9123016 DOI: 10.1038/s41598-022-12239-9] [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: 12/15/2021] [Accepted: 05/06/2022] [Indexed: 11/20/2022] Open
Abstract
In this work, we reported a computational study to quantitatively determine the individual contributions of three candidate arrhythmic factors associated with Brugada Syndrome. In particular, we focused our analysis on the role of structural abnormalities, dispersion of repolarization, and size of the diseased region. We developed a human phenomenological model capable of replicating the action potential characteristics both in Brugada Syndrome and in healthy conditions. Inspired by physiological observations, we employed the phenomenological model in a 2D geometry resembling the pathological RVOT coupled with healthy epicardial tissue. We assessed the insurgence of sustained reentry as a function of electrophysiological and structural abnormalities. Our computational study indicates that both structural and repolarization abnormalities are essential to induce sustained reentry. Furthermore, our results suggest that neither dispersion of repolarization nor structural abnormalities are sufficient on their own to induce sustained reentry. It should be noted how our study seems to explain an arrhythmic mechanism that unifies the classic repolarization and depolarization hypotheses of the pathophysiology of the Brugada Syndrome. Finally, we believe that this work may offer a new perspective on the computational and clinical investigation of Brugada Syndrome and its arrhythmic behaviour.
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Affiliation(s)
- Niccoló Biasi
- Department of Information Engineering, University of Pisa, Pisa, Italy.
| | - Paolo Seghetti
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.,National Research Council, Institute of Clinical Physiology, Pisa, Italy
| | - Alessandro Tognetti
- Department of Information Engineering, University of Pisa, Pisa, Italy.,Research Centre "E. Piaggio", University of Pisa, Pisa, Italy
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12
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Sánchez J, Loewe A. A Review of Healthy and Fibrotic Myocardium Microstructure Modeling and Corresponding Intracardiac Electrograms. Front Physiol 2022; 13:908069. [PMID: 35620600 PMCID: PMC9127661 DOI: 10.3389/fphys.2022.908069] [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: 03/30/2022] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
Computational simulations of cardiac electrophysiology provide detailed information on the depolarization phenomena at different spatial and temporal scales. With the development of new hardware and software, in silico experiments have gained more importance in cardiac electrophysiology research. For plane waves in healthy tissue, in vivo and in silico electrograms at the surface of the tissue demonstrate symmetric morphology and high peak-to-peak amplitude. Simulations provided insight into the factors that alter the morphology and amplitude of the electrograms. The situation is more complex in remodeled tissue with fibrotic infiltrations. Clinically, different changes including fractionation of the signal, extended duration and reduced amplitude have been described. In silico, numerous approaches have been proposed to represent the pathological changes on different spatial and functional scales. Different modeling approaches can reproduce distinct subsets of the clinically observed electrogram phenomena. This review provides an overview of how different modeling approaches to incorporate fibrotic and structural remodeling affect the electrogram and highlights open challenges to be addressed in future research.
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Affiliation(s)
- Jorge Sánchez
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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13
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García-Mendívil L, Pérez-Zabalza M, Mountris K, Duwé S, Smisdom N, Pérez M, Luján L, Wolfs E, Driesen RB, Vallejo-Gil JM, Fresneda-Roldán PC, Fañanás-Mastral J, Vázquez-Sancho M, Matamala-Adell M, Sorribas-Berjón JF, Bellido-Morales JA, Mancebón-Sierra FJ, Vaca-Núñez AS, Ballester-Cuenca C, Oliván-Viguera A, Diez E, Ordovás L, Pueyo E. Analysis of age-related left ventricular collagen remodeling in living donors: Implications in arrhythmogenesis. iScience 2022; 25:103822. [PMID: 35198884 PMCID: PMC8850748 DOI: 10.1016/j.isci.2022.103822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 12/14/2021] [Accepted: 01/25/2022] [Indexed: 12/18/2022] Open
Abstract
Age-related fibrosis in the left ventricle (LV) has been mainly studied in animals by assessing collagen content. Using second-harmonic generation microscopy and image processing, we evaluated amount, aggregation and spatial distribution of LV collagen in young to old pigs, and middle-age and elder living donors. All collagen features increased when comparing adult and old pigs with young ones, but not when comparing adult with old pigs or middle-age with elder individuals. Remarkably, all collagen parameters strongly correlated with lipofuscin, a biological age marker, in humans. By building patient-specific models of human ventricular tissue electrophysiology, we confirmed that amount and organization of fibrosis modulated arrhythmia vulnerability, and that distribution should be accounted for arrhythmia risk assessment. In conclusion, we characterize the age-associated changes in LV collagen and its potential implications for ventricular arrhythmia development. Consistency between pig and human results substantiate the pig as a relevant model of age-related LV collagen dynamics. Collagen remodeling traits change from youth to adulthood, not from midlife onwards In humans, collagen remodeling traits relate with the biological age-pigment lipofuscin Beyond collagen amount, its distribution also influences ventricular arrhythmogenesis Consistent age-related remodeling was observed amid healthy farm pigs and living donors
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Affiliation(s)
- Laura García-Mendívil
- Biomedical Signal Interpretation and Computational Simulation Group (BSICoS), Aragón Institute of Engineering Research, University of Zaragoza, Zaragoza 50018, Spain.,BSICoS, IIS Aragón, Zaragoza 50018, Spain
| | - María Pérez-Zabalza
- Biomedical Signal Interpretation and Computational Simulation Group (BSICoS), Aragón Institute of Engineering Research, University of Zaragoza, Zaragoza 50018, Spain.,BSICoS, IIS Aragón, Zaragoza 50018, Spain
| | - Konstantinos Mountris
- Biomedical Signal Interpretation and Computational Simulation Group (BSICoS), Aragón Institute of Engineering Research, University of Zaragoza, Zaragoza 50018, Spain.,BSICoS, IIS Aragón, Zaragoza 50018, Spain
| | - Sam Duwé
- Advanced Optical Microscopy Centre, Biomedical Research Institute, Hasselt University, Diepenbeek 3500, Belgium
| | - Nick Smisdom
- Biomedical Research Institute, Hasselt University, Diepenbeek 3500, Belgium
| | - Marta Pérez
- Department of Anatomy, Embryology and Animal Genetics, University of Zaragoza, Zaragoza 50013, Spain.,Instituto Universitario de Investigación Mixto Agroalimentario de Aragón (IA2), University of Zaragoza, Zaragoza 50013, Spain
| | - Lluís Luján
- Instituto Universitario de Investigación Mixto Agroalimentario de Aragón (IA2), University of Zaragoza, Zaragoza 50013, Spain.,Department of Animal Pathology, University of Zaragoza, Zaragoza 50013, Spain
| | - Esther Wolfs
- Biomedical Research Institute, Hasselt University, Diepenbeek 3500, Belgium
| | - Ronald B Driesen
- Biomedical Research Institute, Hasselt University, Diepenbeek 3500, Belgium
| | - José María Vallejo-Gil
- Department of Cardiovascular Surgery, University Hospital Miguel Servet, Zaragoza 50009, Spain
| | | | - Javier Fañanás-Mastral
- Department of Cardiovascular Surgery, University Hospital Miguel Servet, Zaragoza 50009, Spain
| | - Manuel Vázquez-Sancho
- Department of Cardiovascular Surgery, University Hospital Miguel Servet, Zaragoza 50009, Spain
| | - Marta Matamala-Adell
- Department of Cardiovascular Surgery, University Hospital Miguel Servet, Zaragoza 50009, Spain
| | | | | | | | | | - Carlos Ballester-Cuenca
- Department of Cardiovascular Surgery, University Hospital Miguel Servet, Zaragoza 50009, Spain
| | - Aida Oliván-Viguera
- Biomedical Signal Interpretation and Computational Simulation Group (BSICoS), Aragón Institute of Engineering Research, University of Zaragoza, Zaragoza 50018, Spain.,BSICoS, IIS Aragón, Zaragoza 50018, Spain.,Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Zaragoza 50018, Spain
| | - Emiliano Diez
- Institute of Experimental Medicine and Biology of Cuyo (IMBECU), CONICET, Mendoza 5500, Argentina
| | - Laura Ordovás
- Biomedical Signal Interpretation and Computational Simulation Group (BSICoS), Aragón Institute of Engineering Research, University of Zaragoza, Zaragoza 50018, Spain.,BSICoS, IIS Aragón, Zaragoza 50018, Spain.,ARAID Foundation, Zaragoza 50018, Spain
| | - Esther Pueyo
- Biomedical Signal Interpretation and Computational Simulation Group (BSICoS), Aragón Institute of Engineering Research, University of Zaragoza, Zaragoza 50018, Spain.,BSICoS, IIS Aragón, Zaragoza 50018, Spain.,Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Zaragoza 50018, Spain
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14
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Cho JH. Sudden Death and Ventricular Arrhythmias in Heart Failure With Preserved Ejection Fraction. Korean Circ J 2022; 52:251-264. [PMID: 35388994 PMCID: PMC8989786 DOI: 10.4070/kcj.2021.0420] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 01/27/2022] [Accepted: 02/22/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Jae Hyung Cho
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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15
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Nezlobinsky T, Okenov A, Panfilov AV. Multiparametric analysis of geometric features of fibrotic textures leading to cardiac arrhythmias. Sci Rep 2021; 11:21111. [PMID: 34702936 PMCID: PMC8548304 DOI: 10.1038/s41598-021-00606-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 09/28/2021] [Indexed: 01/25/2023] Open
Abstract
One of the important questions in cardiac electrophysiology is to characterise the arrhythmogenic substrate; for example, from the texture of the cardiac fibrosis, which is considered one of the major arrhythmogenic conditions. In this paper, we perform an extensive in silico study of the relationships between various local geometric characteristics of fibrosis on the onset of cardiac arrhythmias. In order to define which texture characteristics have better predictive value, we induce arrhythmias by external stimulation, selecting 4363 textures in which arrhythmia can be induced and also selecting 4363 non-arrhythmogenic textures. For each texture, we determine such characteristics as cluster area, solidity, mean distance, local density and zig-zag propagation path, and compare them in arrhythmogenic and non-arrhythmogenic cases. Our study shows that geometrical characteristics, such as cluster area or solidity, turn out to be the most important for prediction of the arrhythmogenic textures. Overall, we were able to achieve an accuracy of 67% for the arrhythmogenic texture-classification problem. However, the accuracy of predictions depends on the size of the region chosen for the analysis. The optimal size for the local areas of the tissue was of the order of 0.28 of the wavelength of the arrhythmia. We discuss further developments and possible applications of this method for characterising the substrate of arrhythmias in fibrotic textures.
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Affiliation(s)
- T Nezlobinsky
- Department of Physics and Astronomy, Ghent University, Krijgslaan 281, 9000, Gent, Belgium.,Ural Federal University, Ekaterinburg, Russia
| | - A Okenov
- Department of Physics and Astronomy, Ghent University, Krijgslaan 281, 9000, Gent, Belgium
| | - A V Panfilov
- Department of Physics and Astronomy, Ghent University, Krijgslaan 281, 9000, Gent, Belgium. .,Ural Federal University, Ekaterinburg, Russia.
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16
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Sankarankutty AC, Greiner J, Bragard J, Visker JR, Shankar TS, Kyriakopoulos CP, Drakos SG, Sachse FB. Etiology-Specific Remodeling in Ventricular Tissue of Heart Failure Patients and Its Implications for Computational Modeling of Electrical Conduction. Front Physiol 2021; 12:730933. [PMID: 34675817 PMCID: PMC8523803 DOI: 10.3389/fphys.2021.730933] [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: 06/25/2021] [Accepted: 09/07/2021] [Indexed: 11/13/2022] Open
Abstract
With an estimated 64.3 million cases worldwide, heart failure (HF) imposes an enormous burden on healthcare systems. Sudden death from arrhythmia is the major cause of mortality in HF patients. Computational modeling of the failing heart provides insights into mechanisms of arrhythmogenesis, risk stratification of patients, and clinical treatment. However, the lack of a clinically informed approach to model cardiac tissues in HF hinders progress in developing patient-specific strategies. Here, we provide a microscopy-based foundation for modeling conduction in HF tissues. We acquired 2D images of left ventricular tissues from HF patients (n = 16) and donors (n = 5). The composition and heterogeneity of fibrosis were quantified at a sub-micrometer resolution over an area of 1 mm2. From the images, we constructed computational bidomain models of tissue electrophysiology. We computed local upstroke velocities of the membrane voltage and anisotropic conduction velocities (CV). The non-myocyte volume fraction was higher in HF than donors (39.68 ± 14.23 vs. 22.09 ± 2.72%, p < 0.01), and higher in ischemic (IC) than nonischemic (NIC) cardiomyopathy (47.2 ± 16.18 vs. 32.16 ± 6.55%, p < 0.05). The heterogeneity of fibrosis within each subject was highest for IC (27.1 ± 6.03%) and lowest for donors (7.47 ± 1.37%) with NIC (15.69 ± 5.76%) in between. K-means clustering of this heterogeneity discriminated IC and NIC with an accuracy of 81.25%. The heterogeneity in CV increased from donor to NIC to IC tissues. CV decreased with increasing fibrosis for longitudinal (R 2 = 0.28, p < 0.05) and transverse conduction (R 2 = 0.46, p < 0.01). The tilt angle of the CV vectors increased 2.1° for longitudinal and 0.91° for transverse conduction per 1% increase in fibrosis. Our study suggests that conduction fundamentally differs in the two etiologies due to the characteristics of fibrosis. Our study highlights the importance of the etiology-specific modeling of HF tissues and integration of medical history into electrophysiology models for personalized risk stratification and treatment planning.
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Affiliation(s)
- Aparna C Sankarankutty
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States.,Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Joachim Greiner
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg⋅Bad Krozingen, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jean Bragard
- Department of Physics and Applied Mathematics, School of Sciences, University of Navarra, Pamplona, Spain
| | - Joseph R Visker
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States.,Division of Cardiovascular Medicine, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Thirupura S Shankar
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States.,Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Christos P Kyriakopoulos
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States.,Division of Cardiovascular Medicine, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Stavros G Drakos
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States.,Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,Division of Cardiovascular Medicine, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Frank B Sachse
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States.,Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
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17
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Palacio LC, Ugarte JP, Saiz J, Tobón C. The Effects of Fibrotic Cell Type and Its Density on Atrial Fibrillation Dynamics: An In Silico Study. Cells 2021; 10:cells10102769. [PMID: 34685750 PMCID: PMC8534881 DOI: 10.3390/cells10102769] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/03/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022] Open
Abstract
Remodeling in atrial fibrillation (AF) underlines the electrical and structural changes in the atria, where fibrosis is a hallmark of arrhythmogenic structural alterations. Fibrosis is an important feature of the AF substrate and can lead to abnormal conduction and, consequently, mechanical dysfunction. The fibrotic process comprises the presence of fibrotic cells, including fibroblasts, myofibroblasts and fibrocytes, which play an important role during fibrillatory dynamics. This work assesses the effect of the diffuse fibrosis density and the intermingled presence of the three types of fibrotic cells on the dynamics of persistent AF. For this purpose, the three fibrotic cells were electrically coupled to cardiomyocytes in a 3D realistic model of human atria. Low (6.25%) and high (25%) fibrosis densities were implemented in the left atrium according to a diffuse fibrosis representation. We analyze the action potential duration, conduction velocity and fibrillatory conduction patterns. Additionally, frequency analysis was performed in 50 virtual electrograms. The tested fibrosis configurations generated a significant conduction velocity reduction, where the larger effect was observed at high fibrosis density (up to 82% reduction in the fibrocytes configuration). Increasing the fibrosis density intensifies the vulnerability to multiple re-entries, zigzag propagation, and chaotic activity in the fibrillatory conduction. The most complex propagation patterns were observed at high fibrosis densities and the fibrocytes are the cells with the largest proarrhythmic effect. Left-to-right dominant frequency gradients can be observed for all fibrosis configurations, where the fibrocytes configuration at high density generates the most significant gradients (up to 4.5 Hz). These results suggest the important role of different fibrotic cell types and their density in diffuse fibrosis on the chaotic propagation patterns during persistent AF.
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Affiliation(s)
- Laura C. Palacio
- Materiales Nanoestructurados y Biomodelación (MATBIOM), Universidad de Medellín, Medellín 050032, Colombia;
| | - Juan P. Ugarte
- Grupo de Investigación en Modelamiento y Simulación Computacional (GIMSC), Universidad de San Buenaventura, Medellín 050010, Colombia;
| | - Javier Saiz
- Centro de Investigación e Innovación en Bioingeniería (CIB), Universitat Politècnica de València, 46022 Valencia, Spain;
| | - Catalina Tobón
- Materiales Nanoestructurados y Biomodelación (MATBIOM), Universidad de Medellín, Medellín 050032, Colombia;
- Correspondence:
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18
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Irakoze É, Jacquemet V. Multiparameter optimization of nonuniform passive diffusion properties for creating coarse-grained equivalent models of cardiac propagation. Comput Biol Med 2021; 138:104863. [PMID: 34562679 DOI: 10.1016/j.compbiomed.2021.104863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 11/30/2022]
Abstract
The arrhythmogenic role of discrete cardiac propagation may be assessed by comparing discrete (fine-grained) and equivalent continuous (coarse-grained) models. We aim to develop an optimization algorithm for estimating the smooth conductivity field that best reproduces the diffusion properties of a given discrete model. Our algorithm iteratively adjusts local conductivity of the coarse-grained continuous model by simulating passive diffusion from white noise initial conditions during 3-10 ms and computing the root mean square error with respect to the discrete model. The coarse-grained conductivity field was interpolated from up to 300 evenly spaced control points. We derived an approximate formula for the gradient of the cost function that required (in two dimensions) only two additional simulations per iteration regardless of the number of estimated parameters. Conjugate gradient solver facilitated simultaneous optimization of multiple conductivity parameters. The method was tested in rectangular anisotropic tissues with uniform and nonuniform conductivity (slow regions with sinusoidal profile) and random diffuse fibrosis, as well as in a monolayer interconnected cable model of the left atrium with spatially-varying fibrosis density. Comparison of activation maps served as validation. The results showed that after convergence the errors in activation time were < 1 ms for rectangular geometries and 1-3 ms in the atrial model. Our approach based on the comparison of passive properties (<10 ms simulation) avoids performing active propagation simulations (>100 ms) at each iteration while reproducing activation maps, with possible applications to investigating the impact of microstructure on arrhythmias.
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Affiliation(s)
- Éric Irakoze
- Pharmacology and Physiology Department, Institute of Biomedical Engineering, Université de Montréal, Montreal, QC, H3T 1J4, Canada; Hôpital Du Sacré-Cœur de Montréal, Research Center, 5400 Boul. Gouin Ouest, Montreal, QC, H4J 1C5, Canada
| | - Vincent Jacquemet
- Pharmacology and Physiology Department, Institute of Biomedical Engineering, Université de Montréal, Montreal, QC, H3T 1J4, Canada; Hôpital Du Sacré-Cœur de Montréal, Research Center, 5400 Boul. Gouin Ouest, Montreal, QC, H4J 1C5, Canada.
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19
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Halfar R, Lawson BAJ, dos Santos RW, Burrage K. Machine Learning Identification of Pro-arrhythmic Structures in Cardiac Fibrosis. Front Physiol 2021; 12:709485. [PMID: 34483962 PMCID: PMC8415115 DOI: 10.3389/fphys.2021.709485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/30/2021] [Indexed: 12/17/2022] Open
Abstract
Cardiac fibrosis and other scarring of the heart, arising from conditions ranging from myocardial infarction to ageing, promotes dangerous arrhythmias by blocking the healthy propagation of cardiac excitation. Owing to the complexity of the dynamics of electrical signalling in the heart, however, the connection between different arrangements of blockage and various arrhythmic consequences remains poorly understood. Where a mechanism defies traditional understanding, machine learning can be invaluable for enabling accurate prediction of quantities of interest (measures of arrhythmic risk) in terms of predictor variables (such as the arrangement or pattern of obstructive scarring). In this study, we simulate the propagation of the action potential (AP) in tissue affected by fibrotic changes and hence detect sites that initiate re-entrant activation patterns. By separately considering multiple different stimulus regimes, we directly observe and quantify the sensitivity of re-entry formation to activation sequence in the fibrotic region. Then, by extracting the fibrotic structures around locations that both do and do not initiate re-entries, we use neural networks to determine to what extent re-entry initiation is predictable, and over what spatial scale conduction heterogeneities appear to act to produce this effect. We find that structural information within about 0.5 mm of a given point is sufficient to predict structures that initiate re-entry with more than 90% accuracy.
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Affiliation(s)
- Radek Halfar
- IT4Innovations, VSB-Technical University of Ostrava, Ostrava, Czechia
| | - Brodie A. J. Lawson
- Centre for Data Science, School of Mathematical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, School of Mathematical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Rodrigo Weber dos Santos
- Graduate Program in Computational Modeling, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
| | - Kevin Burrage
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, School of Mathematical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
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20
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Imaging Techniques for the Study of Fibrosis in Atrial Fibrillation Ablation: From Molecular Mechanisms to Therapeutical Perspectives. J Clin Med 2021; 10:jcm10112277. [PMID: 34073969 PMCID: PMC8197293 DOI: 10.3390/jcm10112277] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/05/2021] [Accepted: 05/20/2021] [Indexed: 12/24/2022] Open
Abstract
Atrial fibrillation (AF) is the most prevalent form of cardiac arrhythmia. It is often related to diverse pathological conditions affecting the atria and leading to remodeling processes including collagen accumulation, fatty infiltration, and amyloid deposition. All these events generate atrial fibrosis, which contribute to beget AF. In this scenario, cardiac imaging appears as a promising noninvasive tool for monitoring the presence and degree of LA fibrosis and remodeling. The aim of this review is to comprehensively examine the bench mechanisms of atrial fibrosis moving, then to describe the principal imaging techniques that characterize it, such as cardiac magnetic resonance (CMR) and multidetector cardiac computed tomography (MDCT), in order to tailor atrial fibrillation ablation to each individual.
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21
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Hall C, Gehmlich K, Denning C, Pavlovic D. Complex Relationship Between Cardiac Fibroblasts and Cardiomyocytes in Health and Disease. J Am Heart Assoc 2021; 10:e019338. [PMID: 33586463 PMCID: PMC8174279 DOI: 10.1161/jaha.120.019338] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cardiac fibroblasts are the primary cell type responsible for deposition of extracellular matrix in the heart, providing support to the contracting myocardium and contributing to a myriad of physiological signaling processes. Despite the importance of fibrosis in processes of wound healing, excessive fibroblast proliferation and activation can lead to pathological remodeling, driving heart failure and the onset of arrhythmias. Our understanding of the mechanisms driving the cardiac fibroblast activation and proliferation is expanding, and evidence for their direct and indirect effects on cardiac myocyte function is accumulating. In this review, we focus on the importance of the fibroblast-to-myofibroblast transition and the cross talk of cardiac fibroblasts with cardiac myocytes. We also consider the current use of models used to explore these questions.
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Affiliation(s)
- Caitlin Hall
- Institute of Cardiovascular Sciences University of Birmingham United Kingdom
| | - Katja Gehmlich
- Institute of Cardiovascular Sciences University of Birmingham United Kingdom.,Division of Cardiovascular Medicine Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford University of Oxford United Kingdom
| | - Chris Denning
- Biodiscovery Institute University of Nottingham United Kingdom
| | - Davor Pavlovic
- Institute of Cardiovascular Sciences University of Birmingham United Kingdom
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22
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de Lucia C, Wallner M, Corradi D, Pironti G. Editorial: Cardiac Fibrosis, From Lineage Tracing to Therapeutic Application. Front Physiol 2021; 11:641771. [PMID: 33551854 PMCID: PMC7855971 DOI: 10.3389/fphys.2020.641771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 12/22/2020] [Indexed: 11/24/2022] Open
Affiliation(s)
- Claudio de Lucia
- Center for Translational Medicine, Temple University, Philadelphia, PA, United States
| | - Markus Wallner
- Division of Cardiology, Medical University of Graz, Graz, Austria.,Cardiovascular Research Center, Temple University, Philadelphia, PA, United States.,Center for Biomarker Research in Medicine, CBmed GmbH, Graz, Austria
| | - Domenico Corradi
- Unit of Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Gianluigi Pironti
- Cardiology Research Unit, Department of Medicine, Karolinska Institute Stockholm, Solna, Sweden
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23
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Gräni C, Benz DC, Gupta S, Windecker S, Kwong RY. Sudden Cardiac Death in Ischemic Heart Disease. JACC Cardiovasc Imaging 2020; 13:2223-2238. [DOI: 10.1016/j.jcmg.2019.10.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 12/16/2022]
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24
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Abstract
Non-linear electrical waves propagate through the heart and control cardiac contraction. Abnormal wave propagation causes various forms of the heart disease and can be lethal. One of the main causes of abnormality is a condition of cardiac fibrosis, which, from mathematical point of view, is the presence of multiple non-conducting obstacles for wave propagation. The fibrosis can have different texture which varies from diffuse (e.g., small randomly distributed obstacles), patchy (e.g., elongated interstitional stria), and focal (e.g., post-infarct scars) forms. Recently, Nezlobinsky et al. (2020) used 2D biophysical models to quantify the effects of elongation of obstacles (fibrosis texture) and showed that longitudinal and transversal propagation differently depends on the obstacle length resulting in anisotropy for wave propagation. In this paper, we extend these studies to 3D tissue models. We show that 3D consideration brings essential new effects; for the same obstacle length in 3D systems, anisotropy is about two times smaller compared to 2D, however, wave propagation is more stable with percolation threshold of about 60% (compared to 35% in 2D). The percolation threshold increases with the obstacle length for the longitudinal propagation, while it decreases for the transversal propagation. Further, in 3D, the dependency of velocity on the obstacle length for the transversal propagation disappears.
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Singh Y, Shakyawar D, Hu W. Non-ischemic endocardial scar geometric remodeling toward topological machine learning. Proc Inst Mech Eng H 2020; 234:1029-1035. [DOI: 10.1177/0954411920937221] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Scar tissues have been important factors in determining the progression of myocardial diseases and the development of adverse cardiac failure outcomes. Accurate segmentation of the scar tissues can be helpful to the clinicians for risk prediction and better evaluation of cardiovascular diseases. Our goal is to apply topology data analysis toward machine learning algorithms to confirm the geometry of scar tissue, in addition to gaining better visualization and quantification of the scar tissue present. We have introduced architecture for integrating geometry in the form of topology toward machine learning. Morphological image processing was carried out to define the regions of the endocardial wall. We implemented convolutional neural networks on delayed enhancement cardiac computed tomography images for the recognition of scar tissue. Segmented two-dimensional images were stacked up to build the geometry of the scar area for visualization purposes. Mathematical calculations were executed for the validation of the scar tissue in addition to performing morphological image processing and marking the scar tissue present on the endocardial wall of the left ventricular. We applied convolutional neural network over convolution and pooling the layers with small sizes; we achieved 89.23% accuracy, 91.11% sensitivity, and 87.75% specificity, and found the dissimilarity distance between the normal endocardial tissue distances to be 9.37. This new concept in this study contributes toward a better understanding of scar structure and transmural variation of the endocardial wall of the left ventricular.
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Affiliation(s)
- Yashbir Singh
- Biomedical Engineering, Chung Yuan Christian University, Taoyuan
| | - Deepa Shakyawar
- Biomedical Engineering, Chung Yuan Christian University, Taoyuan
| | - Weichih Hu
- Biomedical Engineering, Chung Yuan Christian University, Taoyuan
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26
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Callegari S, Macchi E, Monaco R, Magnani L, Tafuni A, Croci S, Nicastro M, Garrapa V, Banchini A, Becchi G, Corradini E, Goldoni M, Rocchio F, Sala R, Benussi S, Ferrara D, Alfieri O, Corradi D. Clinicopathological Bird's-Eye View of Left Atrial Myocardial Fibrosis in 121 Patients With Persistent Atrial Fibrillation: Developing Architecture and Main Cellular Players. Circ Arrhythm Electrophysiol 2020; 13:e007588. [PMID: 32538131 DOI: 10.1161/circep.119.007588] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Scientific research on atrial fibrosis in atrial fibrillation (AF) has mainly focused on quantitative or molecular features. The purpose of this study was to perform a clinicoarchitectural/structural investigation of fibrosis to provide one key to understanding the electrophysiological/clinical aspects of AF. METHODS We characterized the fibrosis (amount, architecture, cellular components, and ultrastructure) in left atrial biopsies from 121 patients with persistent/long-lasting persistent AF (group 1; 59 males; 60±11 years; 91 mitral disease-related AF, 30 nonmitral disease-related AF) and from 39 patients in sinus rhythm with mitral valve regurgitation (group 2; 32 males; 59±12 years). Ten autopsy hearts served as controls. RESULTS Qualitatively, the fibrosis exhibited the same characteristics in all cases and displayed particular architectural scenarios (which we arbitrarily subdivided into 4 stages) ranging from isolated foci to confluent sclerotic areas. The percentage of fibrosis was larger and at a more advanced stage in group 1 versus group 2 and, within group 1, in patients with rheumatic disease versus nonrheumatic cases. In patients with AF with mitral disease and no rheumatic disease, the percentage of fibrosis and the fibrosis stages correlated with both left atrial volume index and AF duration. The fibrotic areas mainly consisted of type I collagen with only a minor cellular component (especially fibroblasts/myofibroblasts; average value range 69-150 cells/mm2, depending on the areas in AF biopsies). A few fibrocytes-circulating and bone marrow-derived mesenchymal cells-were also detectable. The fibrosis-entrapped cardiomyocytes showed sarcolemmal damage and connexin 43 redistribution/internalization. CONCLUSIONS Atrial fibrosis is an evolving and inhomogeneous histological/architectural change that progresses through different stages ranging from isolated foci to confluent sclerotic zones which-seemingly-constrain impulse conduction across restricted regions of electrotonically coupled cardiomyocytes. The fibrotic areas mainly consist of type I collagen extracellular matrix and, only to a lesser extent, mesenchymal cells.
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Affiliation(s)
- Sergio Callegari
- Center of Excellence for Toxicological Research (CERT) (S.C.), University of Parma, Italy
| | - Emilio Macchi
- Department of Chemistry, Life Sciences and Environmental Sustainability (E.M., L.M., V.G.), University of Parma, Italy
| | - Rodolfo Monaco
- Pathology Unit (R.M., A.T., G.B., E.C., D.C.), Department of Medicine and Surgery, University of Parma, Italy
| | - Luca Magnani
- Department of Chemistry, Life Sciences and Environmental Sustainability (E.M., L.M., V.G.), University of Parma, Italy
| | - Alessandro Tafuni
- Pathology Unit (R.M., A.T., G.B., E.C., D.C.), Department of Medicine and Surgery, University of Parma, Italy
| | - Stefania Croci
- Clinical Immunology, Allergy & Advanced Biotechnologies Unit, Azienda Unità, Sanitaria Locale-IRCCS, Reggio Emilia, Italy (S.C., M.N.)
| | - Maria Nicastro
- Clinical Immunology, Allergy & Advanced Biotechnologies Unit, Azienda Unità, Sanitaria Locale-IRCCS, Reggio Emilia, Italy (S.C., M.N.)
| | - Valentina Garrapa
- Department of Chemistry, Life Sciences and Environmental Sustainability (E.M., L.M., V.G.), University of Parma, Italy
| | - Antonio Banchini
- Forensic Medicine Unit (A.B.), Department of Medicine and Surgery, University of Parma, Italy
| | - Gabriella Becchi
- Pathology Unit (R.M., A.T., G.B., E.C., D.C.), Department of Medicine and Surgery, University of Parma, Italy
| | - Emilia Corradini
- Pathology Unit (R.M., A.T., G.B., E.C., D.C.), Department of Medicine and Surgery, University of Parma, Italy
| | - Matteo Goldoni
- Laboratory of Industrial Toxicology (M.G.), Department of Medicine and Surgery, University of Parma, Italy
| | - Francesca Rocchio
- International Centre for T1D, Paediatric Clinical Research Center Fondazione "Romeo ed Enrica Invernizzi", Department of Biomedical & Clinical Science, Hospital "L. Sacco", University of Milan, Italy (F.R.)
| | - Roberto Sala
- General Pathology Unit (R.S.), Department of Medicine and Surgery, University of Parma, Italy
| | | | - David Ferrara
- Cardiothoracic Surgery Unit, Department of Cardiology, San Raffaele University Hospital, Milan, Italy (D.F., O.A.)
| | - Ottavio Alfieri
- Cardiothoracic Surgery Unit, Department of Cardiology, San Raffaele University Hospital, Milan, Italy (D.F., O.A.)
| | - Domenico Corradi
- Pathology Unit (R.M., A.T., G.B., E.C., D.C.), Department of Medicine and Surgery, University of Parma, Italy
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27
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Majumder R, De Coster T, Kudryashova N, Verkerk AO, Kazbanov IV, Ördög B, Harlaar N, Wilders R, de Vries AA, Ypey DL, Panfilov AV, Pijnappels DA. Self-restoration of cardiac excitation rhythm by anti-arrhythmic ion channel gating. eLife 2020; 9:55921. [PMID: 32510321 PMCID: PMC7316504 DOI: 10.7554/elife.55921] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 06/02/2020] [Indexed: 12/21/2022] Open
Abstract
Homeostatic regulation protects organisms against hazardous physiological changes. However, such regulation is limited in certain organs and associated biological processes. For example, the heart fails to self-restore its normal electrical activity once disturbed, as with sustained arrhythmias. Here we present proof-of-concept of a biological self-restoring system that allows automatic detection and correction of such abnormal excitation rhythms. For the heart, its realization involves the integration of ion channels with newly designed gating properties into cardiomyocytes. This allows cardiac tissue to i) discriminate between normal rhythm and arrhythmia based on frequency-dependent gating and ii) generate an ionic current for termination of the detected arrhythmia. We show in silico, that for both human atrial and ventricular arrhythmias, activation of these channels leads to rapid and repeated restoration of normal excitation rhythm. Experimental validation is provided by injecting the designed channel current for arrhythmia termination in human atrial myocytes using dynamic clamp.
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Affiliation(s)
- Rupamanjari Majumder
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands
| | - Tim De Coster
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands.,Department of Physics and Astronomy, Ghent University, Ghent, Belgium.,Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Nina Kudryashova
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands.,Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Arie O Verkerk
- Department of Medical Biology, Amsterdam UMC, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam UMC, Amsterdam, Netherlands
| | - Ivan V Kazbanov
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Balázs Ördög
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands
| | - Niels Harlaar
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam UMC, Amsterdam, Netherlands
| | - Antoine Af de Vries
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands
| | - Dirk L Ypey
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands
| | - Alexander V Panfilov
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands.,Department of Physics and Astronomy, Ghent University, Ghent, Belgium.,Laboratory of Computational Biology and Medicine, Ural Federal University, Ekaterinburg, Russian Federation
| | - Daniël A Pijnappels
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands
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Leonard-Duke J, Evans S, Hannan RT, Barker TH, Bates JHT, Bonham CA, Moore BB, Kirschner DE, Peirce SM. Multi-scale models of lung fibrosis. Matrix Biol 2020; 91-92:35-50. [PMID: 32438056 DOI: 10.1016/j.matbio.2020.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/13/2020] [Accepted: 04/15/2020] [Indexed: 02/08/2023]
Abstract
The architectural complexity of the lung is crucial to its ability to function as an organ of gas exchange; the branching tree structure of the airways transforms the tracheal cross-section of only a few square centimeters to a blood-gas barrier with a surface area of tens of square meters and a thickness on the order of a micron or less. Connective tissue comprised largely of collagen and elastic fibers provides structural integrity for this intricate and delicate system. Homeostatic maintenance of this connective tissue, via a balance between catabolic and anabolic enzyme-driven processes, is crucial to life. Accordingly, when homeostasis is disrupted by the excessive production of connective tissue, lung function deteriorates rapidly with grave consequences leading to chronic lung conditions such as pulmonary fibrosis. Understanding how pulmonary fibrosis develops and alters the link between lung structure and function is crucial for diagnosis, prognosis, and therapy. Further information gained could help elaborate how the healing process breaks down leading to chronic disease. Our understanding of fibrotic disease is greatly aided by the intersection of wet lab studies and mathematical and computational modeling. In the present review we will discuss how multi-scale modeling has facilitated our understanding of pulmonary fibrotic disease as well as identified opportunities that remain open and have produced techniques that can be incorporated into this field by borrowing approaches from multi-scale models of fibrosis beyond the lung.
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Affiliation(s)
- Julie Leonard-Duke
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Stephanie Evans
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Riley T Hannan
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Thomas H Barker
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Jason H T Bates
- Department of Medicine, Vermont Lung Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Catherine A Bonham
- Division of Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville VA 22908, USA
| | - Bethany B Moore
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, and Department of Microbiology and Immunology, University of Michigan Medical Center, Ann Arbor, MI, 48109, USA
| | - Denise E Kirschner
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Shayn M Peirce
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA; Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA.
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29
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Anisotropic conduction in the myocardium due to fibrosis: the effect of texture on wave propagation. Sci Rep 2020; 10:764. [PMID: 31964904 PMCID: PMC6972912 DOI: 10.1038/s41598-020-57449-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 12/16/2019] [Indexed: 11/22/2022] Open
Abstract
Cardiac fibrosis occurs in many forms of heart disease. It is well established that the spatial pattern of fibrosis, its texture, substantially affects the onset of arrhythmia. However, in most modelling studies fibrosis is represented by multiple randomly distributed short obstacles that mimic only one possible texture, diffuse fibrosis. An important characteristic feature of other fibrosis textures, such as interstitial and patchy textures, is that fibrotic inclusions have substantial length, which is suggested to have a pronounced effect on wave propagation. In this paper, we study the effect of the elongation of inexcitable inclusions (obstacles) on wave propagation in a 2D model of cardiac tissue described by the TP06 model for human ventricular cells. We study in detail how the elongation of obstacles affects various characteristics of the waves. We quantify the anisotropy induced by the textures, its dependency on the obstacle length and the effects of the texture on the shape of the propagating wave. Because such anisotropy is a result of zig-zag propagation we show, for the first time, quantification of the effects of geometry and source-sink relationship, on the zig-zag nature of the pathway of electrical conduction. We also study the effect of fibrosis in the case of pre-existing anisotropy and introduce a procedure for scaling of the fibrosis texture. We show that fibrosis can decrease or increase the preexisting anisotropy depending on its scaled texture.
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30
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Liang C, Wang K, Li Q, Bai J, Zhang H. Influence of the distribution of fibrosis within an area of myocardial infarction on wave propagation in ventricular tissue. Sci Rep 2019; 9:14151. [PMID: 31578428 PMCID: PMC6775234 DOI: 10.1038/s41598-019-50478-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 09/13/2019] [Indexed: 12/22/2022] Open
Abstract
The presence of fibrosis in heart tissue is strongly correlated with an incidence of arrhythmia, which is a leading cause of sudden cardiac death (SCD). However, it remains incompletely understood how different distributions, sizes and positions of fibrotic tissues contribute to arrhythmogenesis. In this study, we designed 4 different ventricular models mimicking wave propagation in cardiac tissues under normal, myocardial infarction (MI), MI with random fibrosis and MI with gradient fibrosis conditions. Simulation results of ideal square tissues indicate that vulnerable windows (VWs) of random and gradient fibrosis distributions are similar with low levels of fibrosis. However, with a high level of fibrosis, the VWs significantly increase in random fibrosis tissue but not in gradient fibrosis tissue. In addition, we systematically analyzed the effects of the size and position of fibrosis tissues on VWs. Simulation results show that it is more likely for a reentry wave to appear when the length of the infarcted area is greater than 25% of the perimeter of the ventricle, when the width is approximately half that of the ventricular wall, or when the infarcted area is attached to the inside or outside of the ventricular wall.
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Affiliation(s)
- Cuiping Liang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang, China
| | - Kuanquan Wang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang, China.
| | - Qince Li
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang, China.
| | - Jieyun Bai
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang, China
| | - Henggui Zhang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang, China.,School of Physics and Astronomy, The University of Manchester, Manchester, UK.,Space Institute of Southern China, Shenzhen, China.,Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease/Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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31
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Pattar SS, Fatehi Hassanabad A, Fedak PWM. Acellular Extracellular Matrix Bioscaffolds for Cardiac Repair and Regeneration. Front Cell Dev Biol 2019; 7:63. [PMID: 31080800 PMCID: PMC6497812 DOI: 10.3389/fcell.2019.00063] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 04/08/2019] [Indexed: 12/19/2022] Open
Abstract
Heart failure is a progressive deterioration of cardiac pump function over time and is often a manifestation of ischemic injury caused by myocardial infarction (MI). Post-MI, structural remodeling of the infarcted myocardium ensues. Dysregulation of extracellular matrix (ECM) homeostasis is a hallmark of structural cardiac remodeling and is largely driven by cardiac fibroblast activation. While initially adaptive, structural cardiac remodeling leads to irreversible heart failure due to the progressive loss of cardiac function. Loss of pump function is associated with myocardial fibrosis, wall thinning, and left ventricular (LV) dilatation. Surgical revascularization of the damaged myocardium via coronary artery bypass graft (CABG) surgery and/or percutaneous coronary intervention (PCI) can enhance myocardial perfusion and is beneficial. However, these interventions alone are unable to prevent progressive fibrotic remodeling and loss of heart function that leads to clinical end-stage heart failure. Acellular biologic ECM scaffolds can be surgically implanted onto injured myocardial regions during open-heart surgery as an adjunct therapy to surgical revascularization. This presents a novel therapeutic approach to alter maladaptive remodeling and promote functional recovery. Acellular ECM bioscaffolds have been shown to provide passive structural support to the damaged myocardium and also to act as a dynamic bioactive reservoir capable of promoting endogenous mechanisms of tissue repair, such as vasculogenesis. The composition and structure of xenogenic acellular ECM bioscaffolds are determined by the physiological requirements of the tissue from which they are derived. The capacity of different tissue-derived acellular bioscaffolds to attenuate cardiac remodeling and restore ECM homeostasis after injury may depend on such properties. Accordingly, the search and discovery of an optimal ECM bioscaffold for use in cardiac repair is warranted and may be facilitated by comparing bioscaffolds. This review will provide a summary of the acellular ECM bioscaffolds currently available for use in cardiac surgery with a focus on how they attenuate cardiac remodeling by providing the necessary environmental cues to promote endogenous mechanisms of tissue repair.
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Affiliation(s)
- Simranjit S Pattar
- Section of Cardiac Surgery, Department of Cardiac Science, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Ali Fatehi Hassanabad
- Section of Cardiac Surgery, Department of Cardiac Science, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Paul W M Fedak
- Section of Cardiac Surgery, Department of Cardiac Science, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
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32
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Kudryashova N, Nizamieva A, Tsvelaya V, Panfilov AV, Agladze KI. Self-organization of conducting pathways explains electrical wave propagation in cardiac tissues with high fraction of non-conducting cells. PLoS Comput Biol 2019; 15:e1006597. [PMID: 30883540 PMCID: PMC6438583 DOI: 10.1371/journal.pcbi.1006597] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 03/28/2019] [Accepted: 02/04/2019] [Indexed: 02/04/2023] Open
Abstract
Cardiac fibrosis occurs in many forms of heart disease and is considered to be one of the main arrhythmogenic factors. Regions with a high density of fibroblasts are likely to cause blocks of wave propagation that give rise to dangerous cardiac arrhythmias. Therefore, studies of the wave propagation through these regions are very important, yet the precise mechanisms leading to arrhythmia formation in fibrotic cardiac tissue remain poorly understood. Particularly, it is not clear how wave propagation is organized at the cellular level, as experiments show that the regions with a high percentage of fibroblasts (65-75%) are still conducting electrical signals, whereas geometric analysis of randomly distributed conducting and non-conducting cells predicts connectivity loss at 40% at the most (percolation threshold). To address this question, we used a joint in vitro-in silico approach, which combined experiments in neonatal rat cardiac monolayers with morphological and electrophysiological computer simulations. We have shown that the main reason for sustainable wave propagation in highly fibrotic samples is the formation of a branching network of cardiomyocytes. We have successfully reproduced the morphology of conductive pathways in computer modelling, assuming that cardiomyocytes align their cytoskeletons to fuse into cardiac syncytium. The electrophysiological properties of the monolayers, such as conduction velocity, conduction blocks and wave fractionation, were reproduced as well. In a virtual cardiac tissue, we have also examined the wave propagation at the subcellular level, detected wavebreaks formation and its relation to the structure of fibrosis and, thus, analysed the processes leading to the onset of arrhythmias. Cardiac arrhythmias are one of the major causes of death in the industrialized world. The most dangerous ones are often caused by the blocks of propagation of electrical signals. One of the common factors that contribute to the likelihood of these blocks, is a condition called cardiac fibrosis. In fibrosis, excitable cardiac tissue is partially replaced with the inexcitable and non-conducting connective tissue. The precise mechanisms leading to arrhythmia formation in fibrotic cardiac tissue remain poorly understood. Therefore, it is important to study wave propagation in fibrosis from cellular to tissue level. In this paper, we study tissues with high densities of non-conducting cells in experiments and computer simulations. We have observed a paradoxical ability of the tissue with extremely high portion of non-conducting cells (up to 75%) to conduct electrical signals and contract synchronously, whereas geometric analysis of randomly distributed cells predicted connectivity loss at 40% at the most. To explain this phenomenon, we have studied the patterns that cardiac cells form in the tissue and reproduced their self-organisation in a computer model. Our virtual model also took into account the polygonal shapes of the spreading cells and explained high arrhythmogenicity of fibrotic tissue.
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Affiliation(s)
- Nina Kudryashova
- Laboratory of Biophysics of Excitable Systems, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Aygul Nizamieva
- Laboratory of Biophysics of Excitable Systems, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Valeriya Tsvelaya
- Laboratory of Biophysics of Excitable Systems, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Alexander V. Panfilov
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
- Laboratory of Computational Biology and Medicine, Ural Federal University, Ekaterinburg, Russia
| | - Konstantin I. Agladze
- Laboratory of Biophysics of Excitable Systems, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- * E-mail:
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33
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Vandersickel N, Watanabe M, Tao Q, Fostier J, Zeppenfeld K, Panfilov AV. Dynamical anchoring of distant arrhythmia sources by fibrotic regions via restructuring of the activation pattern. PLoS Comput Biol 2018; 14:e1006637. [PMID: 30571689 PMCID: PMC6319787 DOI: 10.1371/journal.pcbi.1006637] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 01/04/2019] [Accepted: 11/09/2018] [Indexed: 11/27/2022] Open
Abstract
Rotors are functional reentry sources identified in clinically relevant cardiac arrhythmias, such as ventricular and atrial fibrillation. Ablation targeting rotor sites has resulted in arrhythmia termination. Recent clinical, experimental and modelling studies demonstrate that rotors are often anchored around fibrotic scars or regions with increased fibrosis. However, the mechanisms leading to abundance of rotors at these locations are not clear. The current study explores the hypothesis whether fibrotic scars just serve as anchoring sites for the rotors or whether there are other active processes which drive the rotors to these fibrotic regions. Rotors were induced at different distances from fibrotic scars of various sizes and degree of fibrosis. Simulations were performed in a 2D model of human ventricular tissue and in a patient-specific model of the left ventricle of a patient with remote myocardial infarction. In both the 2D and the patient-specific model we found that without fibrotic scars, the rotors were stable at the site of their initiation. However, in the presence of a scar, rotors were eventually dynamically anchored from large distances by the fibrotic scar via a process of dynamical reorganization of the excitation pattern. This process coalesces with a change from polymorphic to monomorphic ventricular tachycardia. Rotors are waves of cardiac excitation like a tornado causing cardiac arrhythmia. Recent research shows that they are found in ventricular and atrial fibrillation. Burning (via ablation) the site of a rotor can result in the termination of the arrhythmia. Recent studies showed that rotors are often anchored to regions surrounding scar tissue, where part of the tissue still survived called fibrotic tissue. However, it is unclear why these rotors anchor to these locations. Therefore, in this work, we investigated why rotors are so abundant in fibrotic tissue with the help of computer simulations. We performed simulations in a 2D model of human ventricular tissue and in a patient-specific model of a patient with an infarction. We found that even when rotors are initially at large distances from the fibrotic region, they are attracted by this region, to finally end up at the fibrotic tissue. We called this process dynamical anchoring and explained how the process works.
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Affiliation(s)
- Nele Vandersickel
- Department of Physics and Astronomy, Ghent University, Belgium
- * E-mail: (NV); (AVP)
| | - Masaya Watanabe
- Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Qian Tao
- Department of Radiology, Division of Image Processing, Leiden University Medical Centre, Leiden, the Netherlands
| | - Jan Fostier
- Department of Information Technology (INTEC), IDLab, Ghent University — imec, Ghent, Belgium
| | - Katja Zeppenfeld
- Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Alexander V. Panfilov
- Department of Physics and Astronomy, Ghent University, Belgium
- Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
- Laboratory of Computational Biology and Medicine, Ural Federal University, Ekaterinburg, Russia
- * E-mail: (NV); (AVP)
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34
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Grisanti LA. Diabetes and Arrhythmias: Pathophysiology, Mechanisms and Therapeutic Outcomes. Front Physiol 2018; 9:1669. [PMID: 30534081 PMCID: PMC6275303 DOI: 10.3389/fphys.2018.01669] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/06/2018] [Indexed: 12/17/2022] Open
Abstract
The prevalence of diabetes is rapidly increasing and closely associated with cardiovascular morbidity and mortality. While the major cardiovascular complication associated with diabetes is coronary artery disease, it is becoming increasingly apparent that diabetes impacts the electrical conduction system in the heart, resulting in atrial fibrillation, and ventricular arrhythmias. The relationship between diabetes and arrhythmias is complex and multifactorial including autonomic dysfunction, atrial and ventricular remodeling and molecular alterations. This review will provide a comprehensive overview of the link between diabetes and arrhythmias with insight into the common molecular mechanisms, structural alterations and therapeutic outcomes.
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Affiliation(s)
- Laurel A Grisanti
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, United States
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Ectopic beats arise from micro-reentries near infarct regions in simulations of a patient-specific heart model. Sci Rep 2018; 8:16392. [PMID: 30401912 PMCID: PMC6219578 DOI: 10.1038/s41598-018-34304-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 10/12/2018] [Indexed: 02/05/2023] Open
Abstract
Ectopic beats are known to be involved in the initiation of a variety of cardiac arrhythmias. Although their location may vary, ectopic excitations have been found to originate from infarct areas, regions of micro-fibrosis and other heterogeneous tissues. However, the underlying mechanisms that link ectopic foci to heterogeneous tissues have yet to be fully understood. In this work, we investigate the mechanism of micro-reentry that leads to the generation of ectopic beats near infarct areas using a patient-specific heart model. The patient-specific geometrical model of the heart, including scar and peri-infarct zones, is obtained through magnetic resonance imaging (MRI). The infarct region is composed of ischemic myocytes and non-conducting cells (fibrosis, for instance). Electrophysiology is captured using an established cardiac myocyte model of the human ventricle modified to describe ischemia. The simulation results clearly reveal that ectopic beats emerge from micro-reentries that are sustained by the heterogeneous structure of the infarct regions. Because microscopic information about the heterogeneous structure of the infarct regions is not available, Monte-Carlo simulations are used to identify the probabilities of an infarct region to behave as an ectopic focus for different levels of ischemia and different percentages of non-conducting cells. From the proposed model, it is observed that ectopic beats are generated when a percentage of non-conducting cells is near a topological metric known as the percolation threshold. Although the mechanism for micro-reentries was proposed half a century ago to be a source of ectopic beats or premature ventricular contractions during myocardial infarction, the present study is the first to reproduce this mechanism in-silico using patient-specific data.
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36
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Clayton RH. Dispersion of Recovery and Vulnerability to Re-entry in a Model of Human Atrial Tissue With Simulated Diffuse and Focal Patterns of Fibrosis. Front Physiol 2018; 9:1052. [PMID: 30131713 PMCID: PMC6090998 DOI: 10.3389/fphys.2018.01052] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/16/2018] [Indexed: 12/03/2022] Open
Abstract
Fibrosis in atrial tissue can act as a substrate for persistent atrial fibrillation, and can be focal or diffuse. Regions of fibrosis are associated with slowed or blocked conduction, and several approaches have been used to model these effects. In this study a computational model of 2D atrial tissue was used to investigate how the spatial scale of regions of simulated fibrosis influenced the dispersion of action potential duration (APD) and vulnerability to re-entry in simulated normal human atrial tissue, and human tissue that has undergone remodeling as a result of persistent atrial fibrillation. Electrical activity was simulated in a 10 × 10 cm square 2D domain, with a spatially varying diffusion coefficient as described below. Cellular electrophysiology was represented by the Courtemanche model for human atrial cells, with the model parameters set for normal and remodeled cells. The effect of fibrosis was modeled with a smoothly varying diffusion coefficient, obtained from sampling a Gaussian random field (GRF) with length scales of between 1.25 and 10.0 mm. Twenty samples were drawn from each field, and used to allocate a value of diffusion coefficient between 0.05 and 0.2 mm2/ms. Dispersion of APD was assessed in each sample by pacing at a cycle length of 1,000 ms, followed by a premature beat with a coupling interval of 400 ms. Vulnerability to re-entry was assessed with an aggressive pacing protocol with pacing cycle lengths decreasing from 450 to 250 ms in 25 ms intervals for normal tissue and 300–150 ms for remodeled tissue. Simulated fibrosis at smaller spatial scales tended to lengthen APD, increase APD dispersion, and increase vulnerability to sustained re-entry relative to fibrosis at larger spatial scales. This study shows that when fibrosis is represented by smoothly varying tissue diffusion, the spatial scale of fibrosis has important effects on both dispersion of recovery and vulnerability to re-entry.
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Affiliation(s)
- Richard H Clayton
- Department of Computer Science, Insigneo Institute for in-silico Medicine, University of Sheffield, Sheffield, United Kingdom
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37
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Gokhale TA, Asfour H, Verma S, Bursac N, Henriquez CS. Microheterogeneity-induced conduction slowing and wavefront collisions govern macroscopic conduction behavior: A computational and experimental study. PLoS Comput Biol 2018; 14:e1006276. [PMID: 30011279 PMCID: PMC6062105 DOI: 10.1371/journal.pcbi.1006276] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 07/26/2018] [Accepted: 06/04/2018] [Indexed: 11/23/2022] Open
Abstract
The incidence of cardiac arrhythmias is known to be associated with tissue heterogeneities including fibrosis. However, the impact of microscopic structural heterogeneities on conduction in excitable tissues remains poorly understood. In this study, we investigated how acellular microheterogeneities affect macroscopic conduction under conditions of normal and reduced excitability by utilizing a novel platform of paired in vitro and in silico studies to examine the mechanisms of conduction. Regular patterns of nonconductive micro-obstacles were created in confluent monolayers of the previously described engineered-excitable Ex293 cell line. Increasing the relative ratio of obstacle size to intra-obstacle strand width resulted in significant conduction slowing up to 23.6% and a significant increase in wavefront curvature anisotropy, a measure of spatial variation in wavefront shape. Changes in bulk electrical conductivity and in path tortuosity were insufficient to explain these observed macroscopic changes. Rather, microscale behaviors including local conduction slowing due to microscale branching, and conduction acceleration due to wavefront merging were shown to contribute to macroscopic phenomena. Conditions of reduced excitability led to further conduction slowing and a reversal of wavefront curvature anisotropy due to spatially non-uniform effects on microscopic slowing and acceleration. This unique experimental and computation platform provided critical mechanistic insights in the impact of microscopic heterogeneities on macroscopic conduction, pertinent to settings of fibrotic heart disease. It is well known that perturbations in the heart structure are associated with the initiation and maintenance of clinically significant cardiac arrhythmia. While previous studies have examined how single structural perturbations affect local electrical conduction, our understanding of how numerous microscopic heterogeneities act in aggregate to alter macroscopic electrical behavior is limited. In this study, we utilized simplified engineered excitable cells that contain the minimal machinery of excitability and can be directly computationally modeled. By pairing experimental and computational studies, we showed that the microscopic branching and collisions of electrical waves slow and speed conduction, respectively, resulting in macroscopic changes in the speed and pattern of electrical activation. These microscale behaviors are significantly altered under reduced excitability, resulting in exaggerated collision effects. Overall, this study helps improve our understanding of how microscopic structural heterogeneities in excitable tissue lead to abnormal action potential propagation, conducive to arrhythmias.
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Affiliation(s)
- Tanmay A. Gokhale
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Huda Asfour
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Shravan Verma
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
- * E-mail: (NB); (CSH)
| | - Craig S. Henriquez
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
- * E-mail: (NB); (CSH)
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38
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Sachetto R, Alonso S, Dos Santos RW. Killing Many Birds With Two Stones: Hypoxia and Fibrosis Can Generate Ectopic Beats in a Human Ventricular Model. Front Physiol 2018; 9:764. [PMID: 29988469 PMCID: PMC6024351 DOI: 10.3389/fphys.2018.00764] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 05/31/2018] [Indexed: 01/19/2023] Open
Abstract
During cardiac diseases many types of anatomical and functional remodeling of cardiac tissue can occur. In this work, we focus on two conditions: hypoxia and fibrosis, which are part of complex pathological modifications that take place in many cardiac diseases (hypertrophic cardiomyopathy, hypertensive heart disease, and recurrent myocardial infarction) and respiratory diseases (obstructive pulmonary disease, obstructive sleep apnea, and cystic fibrosis). Using computational models of cardiac electrophysiology, we evaluate if the interplay between hypoxia and fibrosis is sufficient to trigger cardiac arrhythmia. We study the mechanisms behind the generation of ectopic beats, an arrhythmic trigger also known as premature ventricular contractions (PVCs), in regions with high hypoxia and fibrosis. First, we modify an electrophysiological model of myocytes of the human left ventricle to include the effects of hypoxia. Second, diffuse fibrosis is modeled by randomly replacing cardiac myocytes by non-excitable and non-conducting cells. The Monte Carlo method is used to evaluate the probability of a region to generate ectopic beats with respect to different levels of hypoxia and fibrosis. In addition, we evaluate the minimum size of three-dimensional slabs needed to sustain reentries for different stimulation protocols. The observed mechanism behind the initiation of ectopic beats is unidirectional block, giving rise to sustained micro-reentries inside the region with diffuse fibrosis and hypoxia. In summary, our results suggest that hypoxia and fibrosis are sufficient for the creation of a focal region in the heart that generates PVCs.
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Affiliation(s)
- Rafael Sachetto
- Department of Computer Science, Universidade Federal de São João del-Rei, São João del-Rei, Brazil.,Graduate Program in Computational Modeling, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
| | - Sergio Alonso
- Graduate Program in Computational Modeling, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil.,Department of Physics, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Rodrigo Weber Dos Santos
- Graduate Program in Computational Modeling, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
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39
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De Coster T, Claus P, Kazbanov IV, Haemers P, Willems R, Sipido KR, Panfilov AV. Arrhythmogenicity of fibro-fatty infiltrations. Sci Rep 2018; 8:2050. [PMID: 29391548 PMCID: PMC5795000 DOI: 10.1038/s41598-018-20450-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 01/18/2018] [Indexed: 12/14/2022] Open
Abstract
The onset of cardiac arrhythmias depends on electrophysiological and structural properties of cardiac tissue. One of the most important changes leading to arrhythmias is characterised by the presence of a large number of non-excitable cells in the heart, of which the most well-known example is fibrosis. Recently, adipose tissue was put forward as another similar factor contributing to cardiac arrhythmias. Adipocytes infiltrate into cardiac tissue and produce in-excitable obstacles that interfere with myocardial conduction. However, adipose infiltrates have a different spatial texture than fibrosis. Over the course of time, adipose tissue also remodels into fibrotic tissue. In this paper we investigate the arrhythmogenic mechanisms resulting from the presence of adipose tissue in the heart using computer modelling. We use the TP06 model for human ventricular cells and study how the size and percentage of adipose infiltrates affects basic properties of wave propagation and the onset of arrhythmias under high frequency pacing in a 2D model for cardiac tissue. We show that although presence of adipose infiltrates can result in the onset of cardiac arrhythmias, its impact is less than that of fibrosis. We quantify this process and discuss how the remodelling of adipose infiltrates affects arrhythmia onset.
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Affiliation(s)
- Tim De Coster
- Department of Physics and Astronomy, Ghent University, Gent, 9000, Belgium. .,Department of Cardiovascular Sciences, KU Leuven, Leuven, 3000, Belgium.
| | - Piet Claus
- Department of Cardiovascular Sciences, KU Leuven, Leuven, 3000, Belgium
| | - Ivan V Kazbanov
- Department of Physics and Astronomy, Ghent University, Gent, 9000, Belgium
| | - Peter Haemers
- Department of Cardiovascular Sciences, KU Leuven, Leuven, 3000, Belgium
| | - Rik Willems
- Department of Cardiovascular Sciences, KU Leuven, Leuven, 3000, Belgium
| | - Karin R Sipido
- Department of Cardiovascular Sciences, KU Leuven, Leuven, 3000, Belgium
| | - Alexander V Panfilov
- Department of Physics and Astronomy, Ghent University, Gent, 9000, Belgium. .,Moscow Institute of Physics and Technology, (State University), Dolgoprudny, Moscow Region, 141701, Russia. .,Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Centre Leiden, Leiden University Medical Center, Leiden, 2333ZA, The Netherlands.
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40
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Reentry via high-frequency pacing in a mathematical model for human-ventricular cardiac tissue with a localized fibrotic region. Sci Rep 2017; 7:15350. [PMID: 29127361 PMCID: PMC5681702 DOI: 10.1038/s41598-017-15735-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 10/02/2017] [Indexed: 11/08/2022] Open
Abstract
Localized heterogeneities, caused by the regional proliferation of fibroblasts, occur in mammalian hearts because of diseases like myocardial infarction. Such fibroblast clumps can become sources of pathological reentrant activities, e.g., spiral or scroll waves of electrical activation in cardiac tissue. The occurrence of reentry in cardiac tissue with heterogeneities, such as fibroblast clumps, can depend on the frequency at which the medium is paced. Therefore, it is important to study the reentry-initiating potential of such fibroblast clumps at different frequencies of pacing. We investigate the arrhythmogenic effects of fibroblast clumps at high- and low-frequency pacing. We find that reentrant waves are induced in the medium more prominently at high-frequency pacing than with low-frequency pacing. We also study the other factors that affect the potential of fibroblast clumps to induce reentry in cardiac tissue. In particular, we show that the ability of a fibroblast clump to induce reentry depends on the size of the clump, the distribution and percentage of fibroblasts in the clump, and the excitability of the medium. We study the process of reentry in two-dimensional and a three-dimensional mathematical models for cardiac tissue.
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41
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Kawatou M, Masumoto H, Fukushima H, Morinaga G, Sakata R, Ashihara T, Yamashita JK. Modelling Torsade de Pointes arrhythmias in vitro in 3D human iPS cell-engineered heart tissue. Nat Commun 2017; 8:1078. [PMID: 29057872 PMCID: PMC5715012 DOI: 10.1038/s41467-017-01125-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 08/21/2017] [Indexed: 12/31/2022] Open
Abstract
Torsade de Pointes (TdP) is a lethal arrhythmia that is often drug-induced, thus there is an urgent need for development of models to test or predict the drug sensitivity of human cardiac tissue. Here, we present an in vitro TdP model using 3D cardiac tissue sheets (CTSs) that contain a mixture of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes and non-myocytes. We simultaneously monitor the extracellular field potential (EFP) and the contractile movement of the CTSs. Upon treatment with IKr channel blockers, CTSs exhibit tachyarrhythmias with characteristics of TdP, including both a typical polymorphic EFP and meandering spiral wave re-entry. The TdP-like waveform is predominantly observed in CTSs with the cell mixture, indicating that cellular heterogeneity and the multi-layered 3D structure are both essential factors for reproducing TdP-like arrhythmias in vitro. This 3D model could provide the mechanistic detail underlying TdP generation and means for drug discovery and safety tests. Torsade de Pointes (TdP) is a life-threatening ventricular arrhythmia often caused by drugs. In response to an urgent need for human tissue TdP models, here the authors describe a 3D human iPS cell-engineered heart tissue that generates TdP in response to drugs, providing a suitable model for studies of TdP mechanism and drug toxicity.
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Affiliation(s)
- Masahide Kawatou
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.,Department of Cardiovascular Surgery, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Hidetoshi Masumoto
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.,Department of Cardiovascular Surgery, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Hiroyuki Fukushima
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Gaku Morinaga
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.,Nippon Boehringer Ingelheim Co., Ltd. Kobe Pharma Research Institute, 6-7-5 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan
| | - Ryuzo Sakata
- Department of Cardiovascular Surgery, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Takashi Ashihara
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, 520-2192, Japan
| | - Jun K Yamashita
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.
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42
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Derangeon M, Montnach J, Cerpa CO, Jagu B, Patin J, Toumaniantz G, Girardeau A, Huang CLH, Colledge WH, Grace AA, Baró I, Charpentier F. Transforming growth factor β receptor inhibition prevents ventricular fibrosis in a mouse model of progressive cardiac conduction disease. Cardiovasc Res 2017; 113:464-474. [PMID: 28339646 DOI: 10.1093/cvr/cvx026] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 02/16/2017] [Indexed: 01/12/2023] Open
Abstract
Aims Loss-of-function mutations in SCN5A, the gene encoding NaV1.5 channel, have been associated with inherited progressive cardiac conduction disease (PCCD). We have proposed that Scn5a heterozygous knock-out (Scn5a+/-) mice, which are characterized by ventricular fibrotic remodelling with ageing, represent a model for PCCD. Our objectives were to identify the molecular pathway involved in fibrosis development and prevent its activation. Methods and results Our study shows that myocardial interstitial fibrosis occurred in Scn5a+/- mice only after 45 weeks of age. Fibrosis was triggered by transforming growth factor β (TGF-β) pathway activation. Younger Scn5a+/- mice were characterized by a higher connexin 43 expression than wild-type (WT) mice. After the age of 45 weeks, connexin 43 expression decreased in both WT and Scn5a+/- mice, although the decrease was larger in Scn5a+/- mice. Chronic inhibition of cardiac sodium current with flecainide (50 mg/kg/day p.o) in WT mice from the age of 6 weeks to the age of 60 weeks did not lead to TGF-β pathway activation and fibrosis. Chronic inhibition of TGF-β receptors with GW788388 (5 mg/kg/day p.o.) in Scn5a+/- mice from the age of 45 weeks to the age of 60 weeks prevented the occurrence of fibrosis. However, current data could not detect reduction in QRS duration with GW788388. Conclusion Myocardial fibrosis secondary to a loss of NaV1.5 is triggered by TGF-β signalling pathway. Those events are more likely secondary to the decreased NaV1.5 sarcolemmal expression rather than the decreased Na+ current per se. TGF-β receptor inhibition prevents age-dependent development of ventricular fibrosis in Scn5a+/- mouse.
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Affiliation(s)
- Mickael Derangeon
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Jérôme Montnach
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Cynthia Ore Cerpa
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Benoit Jagu
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Justine Patin
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Gilles Toumaniantz
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Aurore Girardeau
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Christopher L H Huang
- The Section of Cardiovascular Biology, Departments of Biochemistry and Physiology, University of Cambridge, Downing street, Cambridge CB23EG, UK
| | - William H Colledge
- The Section of Cardiovascular Biology, Departments of Biochemistry and Physiology, University of Cambridge, Downing street, Cambridge CB23EG, UK
| | - Andrew A Grace
- The Section of Cardiovascular Biology, Departments of Biochemistry and Physiology, University of Cambridge, Downing street, Cambridge CB23EG, UK
| | - Isabelle Baró
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France
| | - Flavien Charpentier
- INSERM, UMR1087, l'institut du thorax, quai Moncousu, Nantes F-44000, France.,CNRS, UMR6291, quai Moncousu, Nantes F-44000, France.,Université de Nantes, quai Moncousu, Nantes F-44000, France.,CHU Nantes, Alexis Ricordeau, Nantes F-44000, France
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43
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Kharche SR, Vigmond E, Efimov IR, Dobrzynski H. Computational assessment of the functional role of sinoatrial node exit pathways in the human heart. PLoS One 2017; 12:e0183727. [PMID: 28873427 PMCID: PMC5584965 DOI: 10.1371/journal.pone.0183727] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 08/09/2017] [Indexed: 11/19/2022] Open
Abstract
AIM The human right atrium and sinoatrial node (SAN) anatomy is complex. Optical mapping experiments suggest that the SAN is functionally insulated from atrial tissue except at discrete SAN-atrial electrical junctions called SAN exit pathways, SEPs. Additionally, histological imaging suggests the presence of a secondary pacemaker close to the SAN. We hypothesise that a) an insulating border-SEP anatomical configuration is related to SAN arrhythmia; and b) a secondary pacemaker, the paranodal area, is an alternate pacemaker but accentuates tachycardia. A 3D electro-anatomical computational model was used to test these hypotheses. METHODS A detailed 3D human SAN electro-anatomical mathematical model was developed based on our previous anatomical reconstruction. Electrical activity was simulated using tissue specific variants of the Fenton-Karma action potential equations. Simulation experiments were designed to deploy this complex electro-anatomical system to assess the roles of border-SEPs and paranodal area by mimicking experimentally observed SAN arrhythmia. Robust and accurate numerical algorithms were implemented for solving the mono domain reaction-diffusion equation implicitly, calculating 3D filament traces, and computing dominant frequency among other quantitative measurements. RESULTS A centre to periphery gradient of increasing diffusion was sufficient to permit initiation of pacemaking at the centre of the 3D SAN. Re-entry within the SAN, micro re-entry, was possible by imposing significant SAN fibrosis in the presence of the insulating border. SEPs promoted the micro re-entry to generate more complex SAN-atrial tachycardia. Simulation of macro re-entry, i.e. re-entry around the SAN, was possible by inclusion of atrial fibrosis in the presence of the insulating border. The border shielded the SAN from atrial tachycardia. However, SAN micro-structure intercellular gap junctional coupling and the paranodal area contributed to prolonged atrial fibrillation. Finally, the micro-structure was found to be sufficient to explain shifts of leading pacemaker site location. CONCLUSIONS The simulations establish a relationship between anatomy and SAN electrical function. Microstructure, in the form of intercellular gap junction coupling, was found to regulate SAN function and arrhythmia.
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Affiliation(s)
- Sanjay R. Kharche
- Institute of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - Edward Vigmond
- University of Bordeaux, IMB, UMR 5251, Talence, France
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac- Bordeaux, France
| | - Igor R. Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States of America
| | - Halina Dobrzynski
- Institute of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
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44
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Gokhale TA, Medvescek E, Henriquez CS. Modeling dynamics in diseased cardiac tissue: Impact of model choice. CHAOS (WOODBURY, N.Y.) 2017; 27:093909. [PMID: 28964161 PMCID: PMC5568867 DOI: 10.1063/1.4999605] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/13/2017] [Indexed: 06/07/2023]
Abstract
Cardiac arrhythmias have been traditionally simulated using continuous models that assume tissue homogeneity and use a relatively large spatial discretization. However, it is believed that the tissue fibrosis and collagen deposition, which occur on a micron-level, are critical factors in arrhythmogenesis in diseased tissues. Consequently, it remains unclear how well continuous models, which use averaged electrical properties, are able to accurately capture complex conduction behaviors such as re-entry in fibrotic tissues. The objective of this study was to compare re-entrant behavior in discrete microstructural models of fibrosis and in two types of equivalent continuous models, a homogenous continuous model and a hybrid continuous model with distinct heterogeneities. In the discrete model, increasing levels of tissue fibrosis lead to a substantial increase in the re-entrant cycle length which is inadequately reflected in the homogenous continuous models. These cycle length increases appear to be primarily due to increases in the tip path length and to altered restitution behavior, and suggest that it is critical to consider the discrete effects of fibrosis on conduction when studying arrhythmogenesis in fibrotic myocardium. Hybrid models are able to accurately capture some aspects of re-entry and, if carefully tuned, may provide a framework for simulating conduction in diseased tissues with both accuracy and efficiency.
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Affiliation(s)
- Tanmay A Gokhale
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708-0281, USA
| | - Eli Medvescek
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708-0281, USA
| | - Craig S Henriquez
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708-0281, USA
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45
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Okada A, Kashima Y, Tomita T, Takeuchi T, Oguchi Y, Yoshie K, Shoin W, Shoda M, Nitta K, Kuwahara K, Imamura H. Cardiac hyaluronan may be associated with the persistence of atrial fibrillation. Heart Vessels 2017; 32:1144-1150. [PMID: 28378212 DOI: 10.1007/s00380-017-0972-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 03/24/2017] [Indexed: 11/26/2022]
Abstract
Hyaluronan (HA), a primary component of the extracellular matrix, is associated with several cardiovascular diseases. However, its precise cardiac origin and role in atrial fibrillation (AF) remain unclear. We investigated chamber-specific HA levels in patients with paroxysmal AF (PAF) or persistent AF (PSAF). The levels of HA, a diacron-reactive oxygen metabolite (dROM) as a marker for oxidative stress, at different cardiac sites, and peripheral brain natriuretic peptide (BNP) levels were measured in patients with PAF (n = 50) or PSAF (n = 35). HA levels in the coronary sinus (CS-HA) were significantly higher than those other sites, in both PAF and PSAF patients, and CS-HA levels were significantly higher in PSAF patients than in PAF patients [37.1 (interquartile range, 31.2-48.3) vs. 30.6 (23.7-40.2) pg/mL, P < 0.01]. CS-HA levels were correlated with CS-dROM levels and peripheral BNP levels in PSAF patients (r = 0.417, P = 0.03 and r = 0.579, P < 0.001, respectively), but not in PAF patients (r = -0.115, P = 0.421 and r = 0.048, P = 0.740, respectively). CS-HA levels were elevated in both PAF and PSAF patients and were correlated with cardiac oxidative stress and BNP levels in PSAF patients. Cardiac HA may be associated with the persistence of AF.
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Affiliation(s)
- Ayako Okada
- Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Yuichiro Kashima
- Department of Emergency and Critical Care Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan.
| | - Takeshi Tomita
- Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Takahiro Takeuchi
- Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Yasutaka Oguchi
- Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Koji Yoshie
- Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Wataru Shoin
- Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Morio Shoda
- Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Kenichi Nitta
- Department of Emergency and Critical Care Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
| | - Koichiro Kuwahara
- Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Hiroshi Imamura
- Department of Emergency and Critical Care Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
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Imaging of Myocardial Fibrosis in Patients with End-Stage Renal Disease: Current Limitations and Future Possibilities. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5453606. [PMID: 28349062 PMCID: PMC5352874 DOI: 10.1155/2017/5453606] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 01/30/2017] [Accepted: 02/12/2017] [Indexed: 12/16/2022]
Abstract
Cardiovascular disease in patients with end-stage renal disease (ESRD) is driven by a different set of processes than in the general population. These processes lead to pathological changes in cardiac structure and function that include the development of left ventricular hypertrophy and left ventricular dilatation and the development of myocardial fibrosis. Reduction in left ventricular hypertrophy has been the established goal of many interventional trials in patients with chronic kidney disease, but a recent systematic review has questioned whether reduction of left ventricular hypertrophy improves cardiovascular mortality as previously thought. The development of novel imaging biomarkers that link to cardiovascular outcomes and that are specific to the disease processes in ESRD is therefore required. Postmortem studies of patients with ESRD on hemodialysis have shown that the extent of myocardial fibrosis is strongly linked to cardiovascular death and accurate imaging of myocardial fibrosis would be an attractive target as an imaging biomarker. In this article we will discuss the current imaging methods available to measure myocardial fibrosis in patients with ESRD, the reliability of the techniques, specific challenges and important limitations in patients with ESRD, and how to further develop the techniques we have so they are sufficiently robust for use in future clinical trials.
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Sridhar S, Vandersickel N, Panfilov AV. Effect of myocyte-fibroblast coupling on the onset of pathological dynamics in a model of ventricular tissue. Sci Rep 2017; 7:40985. [PMID: 28106124 PMCID: PMC5247688 DOI: 10.1038/srep40985] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/13/2016] [Indexed: 12/23/2022] Open
Abstract
Managing lethal cardiac arrhythmias is one of the biggest challenges in modern cardiology, and hence it is very important to understand the factors underlying such arrhythmias. While early afterdepolarizations (EAD) of cardiac cells is known to be one such arrhythmogenic factor, the mechanisms underlying the emergence of tissue level arrhythmias from cellular level EADs is not fully understood. Another known arrhythmogenic condition is fibrosis of cardiac tissue that occurs both due to aging and in many types of heart diseases. In this paper we describe the results of a systematic in-silico study, using the TNNP model of human cardiac cells and MacCannell model for (myo)fibroblasts, on the possible effects of diffuse fibrosis on arrhythmias occurring via EADs. We find that depending on the resting potential of fibroblasts (VFR), M-F coupling can either increase or decrease the region of parameters showing EADs. Fibrosis increases the probability of occurrence of arrhythmias after a single focal stimulation and this effect increases with the strength of the M-F coupling. While in our simulations, arrhythmias occur due to fibrosis induced ectopic activity, we do not observe any specific fibrotic pattern that promotes the occurrence of these ectopic sources.
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Affiliation(s)
- S. Sridhar
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Nele Vandersickel
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Alexander V. Panfilov
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, Russia
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Reentry and Ectopic Pacemakers Emerge in a Three-Dimensional Model for a Slab of Cardiac Tissue with Diffuse Microfibrosis near the Percolation Threshold. PLoS One 2016; 11:e0166972. [PMID: 27875591 PMCID: PMC5119821 DOI: 10.1371/journal.pone.0166972] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 11/07/2016] [Indexed: 02/07/2023] Open
Abstract
Arrhythmias in cardiac tissue are generally associated with irregular electrical wave propagation in the heart. Cardiac tissue is formed by a discrete cell network, which is often heterogeneous. Recently, it was shown in simulations of two-dimensional (2D) discrete models of cardiac tissue that a wave crossing a fibrotic, heterogeneous region may produce reentry and transient or persistent ectopic activity provided the fraction of conducting connections is just above the percolation threshold. Here, we investigate the occurrence of these phenomena in three-dimensions by simulations of a discrete model representing a thin slab of cardiac tissue. This is motivated (i) by the necessity to study the relevance and properties of the percolation-related mechanism for the emergence of microreentries in three dimensions and (ii) by the fact that atrial tissue is quite thin in comparison with ventricular tissue. Here, we simplify the model by neglecting details of tissue anatomy, e. g. geometries of atria or ventricles and the anisotropy in the conductivity. Hence, our modeling study is confined to the investigation of the effect of the tissue thickness as well as to the comparison of the dynamics of electrical excitation in a 2D layer with the one in a 3D slab. Our results indicate a strong and non-trivial effect of the thickness even for thin tissue slabs on the probability of microreentries and ectopic beat generation. The strong correlation of the occurrence of microreentry with the percolation threshold reported earlier in 2D layers persists in 3D slabs. Finally, a qualitative agreement of 3D simulated electrograms in the fibrotic region with the experimentally observed complex fractional atrial electrograms (CFAE) as well as strong difference between simulated electrograms in 2D and 3D were found for the cases where reentry and ectopic activity were triggered by the micro-fibrotic region.
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Alonso S, Bär M, Echebarria B. Nonlinear physics of electrical wave propagation in the heart: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:096601. [PMID: 27517161 DOI: 10.1088/0034-4885/79/9/096601] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The beating of the heart is a synchronized contraction of muscle cells (myocytes) that is triggered by a periodic sequence of electrical waves (action potentials) originating in the sino-atrial node and propagating over the atria and the ventricles. Cardiac arrhythmias like atrial and ventricular fibrillation (AF,VF) or ventricular tachycardia (VT) are caused by disruptions and instabilities of these electrical excitations, that lead to the emergence of rotating waves (VT) and turbulent wave patterns (AF,VF). Numerous simulation and experimental studies during the last 20 years have addressed these topics. In this review we focus on the nonlinear dynamics of wave propagation in the heart with an emphasis on the theory of pulses, spirals and scroll waves and their instabilities in excitable media with applications to cardiac modeling. After an introduction into electrophysiological models for action potential propagation, the modeling and analysis of spatiotemporal alternans, spiral and scroll meandering, spiral breakup and scroll wave instabilities like negative line tension and sproing are reviewed in depth and discussed with emphasis on their impact for cardiac arrhythmias.
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Affiliation(s)
- Sergio Alonso
- Physikalisch-Technische Bundesanstalt, Abbestr. 2-12 10587, Berlin, Germany. Department of Physics, Universitat Politècnica de Catalunya, Av. Dr. Marañón 44, E-08028 Barcelona, Spain
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Mayourian J, Savizky RM, Sobie EA, Costa KD. Modeling Electrophysiological Coupling and Fusion between Human Mesenchymal Stem Cells and Cardiomyocytes. PLoS Comput Biol 2016; 12:e1005014. [PMID: 27454812 PMCID: PMC4959759 DOI: 10.1371/journal.pcbi.1005014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 06/08/2016] [Indexed: 01/16/2023] Open
Abstract
Human mesenchymal stem cell (hMSC) delivery has demonstrated promise in preclinical and clinical trials for myocardial infarction therapy; however, broad acceptance is hindered by limited understanding of hMSC-human cardiomyocyte (hCM) interactions. To better understand the electrophysiological consequences of direct heterocellular connections between hMSCs and hCMs, three original mathematical models were developed, representing an experimentally verified triad of hMSC families with distinct functional ion channel currents. The arrhythmogenic risk of such direct electrical interactions in the setting of healthy adult myocardium was predicted by coupling and fusing these hMSC models to the published ten Tusscher midcardial hCM model. Substantial variations in action potential waveform—such as decreased action potential duration (APD) and plateau height—were found when hCMs were coupled to the two hMSC models expressing functional delayed rectifier-like human ether à-go-go K+ channel 1 (hEAG1); the effects were exacerbated for fused hMSC-hCM hybrid cells. The third family of hMSCs (Type C), absent of hEAG1 activity, led to smaller single-cell action potential alterations during coupling and fusion, translating to longer tissue-level mean action potential wavelength. In a simulated 2-D monolayer of cardiac tissue, re-entry vulnerability with low (5%) hMSC insertion was approximately eight-fold lower with Type C hMSCs compared to hEAG1-functional hMSCs. A 20% decrease in APD dispersion by Type C hMSCs compared to hEAG1-active hMSCs supports the claim of reduced arrhythmogenic potential of this cell type with low hMSC insertion. However, at moderate (15%) and high (25%) hMSC insertion, the vulnerable window increased independent of hMSC type. In summary, this study provides novel electrophysiological models of hMSCs, predicts possible arrhythmogenic effects of hMSCs when directly coupled to healthy hCMs, and proposes that isolating a subset of hMSCs absent of hEAG1 activity may offer increased safety as a cell delivery cardiotherapy at low levels of hMSC-hCM coupling. Myocardial infarction—better known as a heart attack—strikes on average every 43 seconds in America. An emerging approach to treat myocardial infarction patients involves the delivery of human mesenchymal stem cells (hMSCs) to the damaged heart. While clinical trials of this therapeutic approach have yet to report adverse effects on heart electrical rhythm, such consequences have been implicated in simpler experimental systems and thus remain a concern. In this study, we utilized mathematical modeling to simulate electrical interactions arising from direct coupling between hMSCs and human heart cells to develop insight into the possible adverse effects of this therapeutic approach on human heart electrical activity, and to assess a novel strategy for reducing some potential risks of this therapy. We developed the first mathematical models of electrical activity of three families of hMSCs based on published experimental data, and integrated these with previously established mathematical models of human heart cell electrical activity. Our computer simulations demonstrated that one particular family of hMSCs minimized the disturbances in cardiac electrical activity both at the single-cell and tissue levels, suggesting that isolating this specific sub-population of hMSCs for myocardial delivery could potentially increase the safety of future hMSC-based heart therapies.
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Affiliation(s)
- Joshua Mayourian
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Ruben M. Savizky
- Department of Chemistry, The Cooper Union, New York, New York, United States of America
| | - Eric A. Sobie
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Kevin D. Costa
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- * E-mail:
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