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Trayanova NA, Lyon A, Shade J, Heijman J. Computational modeling of cardiac electrophysiology and arrhythmogenesis: toward clinical translation. Physiol Rev 2024; 104:1265-1333. [PMID: 38153307 DOI: 10.1152/physrev.00017.2023] [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: 04/05/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 12/29/2023] Open
Abstract
The complexity of cardiac electrophysiology, involving dynamic changes in numerous components across multiple spatial (from ion channel to organ) and temporal (from milliseconds to days) scales, makes an intuitive or empirical analysis of cardiac arrhythmogenesis challenging. Multiscale mechanistic computational models of cardiac electrophysiology provide precise control over individual parameters, and their reproducibility enables a thorough assessment of arrhythmia mechanisms. This review provides a comprehensive analysis of models of cardiac electrophysiology and arrhythmias, from the single cell to the organ level, and how they can be leveraged to better understand rhythm disorders in cardiac disease and to improve heart patient care. Key issues related to model development based on experimental data are discussed, and major families of human cardiomyocyte models and their applications are highlighted. An overview of organ-level computational modeling of cardiac electrophysiology and its clinical applications in personalized arrhythmia risk assessment and patient-specific therapy of atrial and ventricular arrhythmias is provided. The advancements presented here highlight how patient-specific computational models of the heart reconstructed from patient data have achieved success in predicting risk of sudden cardiac death and guiding optimal treatments of heart rhythm disorders. Finally, an outlook toward potential future advances, including the combination of mechanistic modeling and machine learning/artificial intelligence, is provided. As the field of cardiology is embarking on a journey toward precision medicine, personalized modeling of the heart is expected to become a key technology to guide pharmaceutical therapy, deployment of devices, and surgical interventions.
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Affiliation(s)
- Natalia A Trayanova
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
- Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, Maryland, United States
| | - Aurore Lyon
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Julie Shade
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
- Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, Maryland, United States
| | - Jordi Heijman
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
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Hu W, Zhang W, Zhang K, Al-Moubarak E, Zhang Y, Harmer SC, Hancox JC, Zhang H. Evaluating pro-arrhythmogenic effects of the T634S-hERG mutation: insights from a simulation study. Interface Focus 2023; 13:20230035. [PMID: 38106919 PMCID: PMC10722218 DOI: 10.1098/rsfs.2023.0035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 11/06/2023] [Indexed: 12/19/2023] Open
Abstract
A mutation to serine of a conserved threonine (T634S) in the hERG K+ channel S6 pore region has been identified as a variant of uncertain significance, showing a loss-of-function effect. However, its potential consequences for ventricular excitation and arrhythmogenesis have not been reported. This study evaluated possible functional effects of the T634S-hERG mutation on ventricular excitation and arrhythmogenesis by using multi-scale computer models of the human ventricle. A Markov chain model of the rapid delayed rectifier potassium current (IKr) was reconstructed for wild-type and T634S-hERG mutant conditions and incorporated into the ten Tusscher et al. models of human ventricles at cell and tissue (1D, 2D and 3D) levels. Possible functional impacts of the T634S-hERG mutation were evaluated by its effects on action potential durations (APDs) and their rate-dependence (APDr) at the cell level; and on the QT interval of pseudo-ECGs, tissue vulnerability to unidirectional conduction block (VW), spiral wave dynamics and repolarization dispersion at the tissue level. It was found that the T634S-hERG mutation prolonged cellular APDs, steepened APDr, prolonged the QT interval, increased VW, destablized re-entry and augmented repolarization dispersion across the ventricle. Collectively, these results imply potential pro-arrhythmic effects of the T634S-hERG mutation, consistent with LQT2.
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Affiliation(s)
- Wei Hu
- Biological Physics Group, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - Wenfeng Zhang
- College of Computer and Information Science, Chongqing Normal University, Chongqing, People's Republic of China
| | - Kevin Zhang
- Southmead Hospital, North Bristol Trust, Bristol, UK
| | - Ehab Al-Moubarak
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Yihong Zhang
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Stephen C. Harmer
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Jules C. Hancox
- Biological Physics Group, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Henggui Zhang
- Biological Physics Group, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou 646000, People's Republic of China
- Beijing Academy of Artificial Intelligence, Beijing 100084, People's Republic of China
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Li Y, Wan R, Liu J, Liu W, Ma L, Zhang H. In silico mechanisms of arsenic trioxide-induced cardiotoxicity. Front Physiol 2022; 13:1004605. [PMID: 36589437 PMCID: PMC9798418 DOI: 10.3389/fphys.2022.1004605] [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: 07/27/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
It has been found that arsenic trioxide (ATO) is effective in treating acute promyelocytic leukemia (APL). However, long QT syndrome was reported in patients receiving therapy using ATO, which even led to sudden cardiac death. The underlying mechanisms of ATO-induced cardiotoxicity have been investigated in some biological experiments, showing that ATO affects human ether-à-go-go-related gene (hERG) channels, coding rapid delayed rectifier potassium current (I Kr ), as well as L-type calcium (I CaL ) channels. Nevertheless, the mechanism by which these channel reconstitutions induced the arrhythmia in ventricular tissue remains unsolved. In this study, a mathematical model was developed to simulate the effect of ATO on ventricular electrical excitation at cellular and tissue levels by considering ATO's effects on I Kr and I CaL . The ATO-dose-dependent pore block model was incorporated into the I Kr model, and the enhanced degree of ATO to I CaL was based on experimental data. Simulation results indicated that ATO extended the action potential duration of three types of ventricular myocytes (VMs), including endocardial cells (ENDO), midmyocardial cells (MCELL), and epicardial cells (EPI), and exacerbated the heterogeneity among them. ATO could also induce alternans in all three kinds of VMs. In a cable model of the intramural ventricular strand, the effects of ATO are reflected in a prolonged QT interval of simulated pseudo-ECG and a wide vulnerable window, thus increasing the possibility of spiral wave formation in ventricular tissue. In addition to showing that ATO prolonged QT, we revealed that the heterogeneity caused by ATO is also an essential hazard factor. Based on this, a pharmacological intervention of ATO toxicity by resveratrol was undertaken. This study provides a further understanding of ATO-induced cardiotoxicity, which may help to improve the treatment for APL patients.
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Affiliation(s)
- Yacong Li
- Beijing Academy of Artificial Intelligence, Beijing, China
| | - Runlan Wan
- Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Jun Liu
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China,Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China,*Correspondence: Jun Liu, ; Weichao Liu, ; Henggui Zhang,
| | - Weichao Liu
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China,*Correspondence: Jun Liu, ; Weichao Liu, ; Henggui Zhang,
| | - Lei Ma
- Beijing Academy of Artificial Intelligence, Beijing, China,National Biomedical Imaging Center, Peking University, Beijing, China
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom,*Correspondence: Jun Liu, ; Weichao Liu, ; Henggui Zhang,
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Computational analysis of arrhythmogenesis in KCNH2 T618I mutation-associated short QT syndrome and the pharmacological effects of quinidine and sotalol. NPJ Syst Biol Appl 2022; 8:43. [PMCID: PMC9636227 DOI: 10.1038/s41540-022-00254-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
Abstract
Short QT syndrome (SQTS) is a rare but dangerous genetic disease. In this research, we conducted a comprehensive in silico investigation into the arrhythmogenesis in KCNH2 T618I-associated SQTS using a multi-scale human ventricle model. A Markov chain model of IKr was developed firstly to reproduce the experimental observations. It was then incorporated into cell, tissue, and organ models to explore how the mutation provided substrates for ventricular arrhythmias. Using this T618I Markov model, we explicitly revealed the subcellular level functional alterations by T618I mutation, particularly the changes of ion channel states that are difficult to demonstrate in wet experiments. The following tissue and organ models also successfully reproduced the changed dynamics of reentrant spiral waves and impaired rate adaptions in hearts of T618I mutation. In terms of pharmacotherapy, we replicated the different effects of a drug under various conditions using identical mathematical descriptions for drugs. This study not only simulated the actions of an effective drug (quinidine) at various physiological levels, but also elucidated why the IKr inhibitor sotalol failed in SQT1 patients through profoundly analyzing its mutation-dependent actions.
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Krahn AD, Tfelt-Hansen J, Tadros R, Steinberg C, Semsarian C, Han HC. Latent Causes of Sudden Cardiac Arrest. JACC Clin Electrophysiol 2022; 8:806-821. [PMID: 35738861 DOI: 10.1016/j.jacep.2021.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/09/2021] [Accepted: 12/29/2021] [Indexed: 11/30/2022]
Abstract
Inherited arrhythmia syndromes are a common cause of apparently unexplained cardiac arrest or sudden cardiac death. These include long QT syndrome and Brugada syndrome, with a well-recognized phenotype in most patients with sufficiently severe disease to lead to cardiac arrest. Less common and typically less apparent conditions that may not be readily evident include catecholaminergic polymorphic ventricular tachycardia, short QT syndrome and early repolarization syndrome. In cardiac arrest patients whose extensive testing does not reveal an underlying etiology, a diagnosis of idiopathic ventricular fibrillation or short-coupled ventricular fibrillation is assigned. This review summarizes our current understanding of the less common inherited arrhythmia syndromes and provides clinicians with a practical approach to diagnosis and management.
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Affiliation(s)
- Andrew D Krahn
- Center for Cardiovascular Innovation, Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Jacob Tfelt-Hansen
- The Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Department of Forensic Medicine, Faculty of Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rafik Tadros
- Cardiovascular Genetics Center, Montreal Heart Institute, Department of Medicine, Université de Montréal, Montreal, Québec, Canada
| | - Christian Steinberg
- Institut universitaire de cardiologie et pneumologie de Québec (IUCPQ-UL), Laval University, Inherited Arrhythmia Services, Départment of Cardiology and Cardiac Surgery, Québec, Canada
| | - Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology at Centenary Institute, The University of Sydney, Sydney, New South Wales, Australia
| | - Hui-Chen Han
- Center for Cardiovascular Innovation, Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada; Victorian Heart Institute, Monash University, Clayton, Victoria, Australia
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Jiang H, Zhang S, Bi X, Ma W, Wei Z. Proarrhythmic effects of carbon monoxide in human ventricular tissue: insights from computational modeling. Comput Biol Med 2022; 140:105066. [PMID: 34839185 DOI: 10.1016/j.compbiomed.2021.105066] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/20/2021] [Accepted: 11/21/2021] [Indexed: 11/03/2022]
Abstract
Epidemiological studies have demonstrated that ambient air pollution has been closely associated with cardiovascular diseases. Carbon monoxide (CO) is a common ambient air pollutant that can cause adverse effects on the heart. CO is known to cause tissue ischemia, resulting in ventricular arrhythmias. However, accumulating biological studies showed that CO could exert effects on multiple cardiac ionic channels under normoxic conditions, which might indicate new proarrhythmic mechanisms other than ischemia-mediated electrophysiology changes. In this work, we evaluated the functional impacts of CO on human ventricles using a multi-scale model of human ventricular tissue. Experimental data regarding the effects of CO on different ion channels were incorporated into the cell model to explore the alterations of ventricular electrophysiology. Simulation results suggested that CO significantly prolonged the duration of ventricular action potentials, enhanced the transmural dispersion of repolarization, and reduced the adaptability of ventricular tissue to fast heart rates. In addition, simulated pseudo-ECGs showed consistent manifestations with the clinical observation that CO caused an apparent QT interval prolongation and T-wave widening, indicating that CO affected the heart's abnormal ventricular repolarization.
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Affiliation(s)
- Huasen Jiang
- College of Computer Science and Technology, Ocean University of China, Qingdao, 266100, China
| | - Shugang Zhang
- College of Computer Science and Technology, Ocean University of China, Qingdao, 266100, China.
| | - Xiangpeng Bi
- College of Computer Science and Technology, Ocean University of China, Qingdao, 266100, China
| | - Wenjian Ma
- College of Computer Science and Technology, Ocean University of China, Qingdao, 266100, China
| | - Zhiqiang Wei
- College of Computer Science and Technology, Ocean University of China, Qingdao, 266100, China
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Bi X, Zhang S, Jiang H, Wei Z. A Multi-Scale Computational Model for the Rat Ventricle: Construction, Parallelization, and Applications. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 208:106289. [PMID: 34303152 DOI: 10.1016/j.cmpb.2021.106289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/10/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Cardiovascular diseases are the top killer of human beings. The ventricular arrhythmia, as a type of malignant cardiac arrhythmias, typically leads to death if not treated within minutes. The multi-scale virtual heart provides an idealized tool for exploring the underlying mechanisms, by means of incorporating abundant experimental data at the level of ion channels and analyzing the subsequent pathological changes at organ levels. However, there are few studies on building a virtual heart model for rats-a species most widely used in experiments. OBJECTIVE To build a multi-scale computational model for rats, with detailed methodology for the model construction, computational optimization, and its applications. METHODS First, approaches for building multi-scale models ranging from cellular to 3-D organ levels are introduced, with detailed descriptions of handling the ventricular myocardium heterogeneity, geometry processing, and boundary conditions, etc. Next, for dealing with the expensive computational costs of 3-D models, optimization approaches including an optimized representation and a GPU-based parallelization method are introduced. Finally, methods for reproducing of some key phenomenon (e.g., electrocardiograph, spiral/scroll waves) are demonstrated. RESULTS Three types of heterogeneity, including the transmural heterogeneity, the interventricular heterogeneity, and the base-apex heterogeneity are incorporated into the model. The normal and reentrant excitation waves, as well as the corresponding pseudo-ECGs are reproduced by the constructed ventricle model. In addition, the temporal and spatial vulnerability to reentry arrhythmias are quantified based on the evaluation experiments of vulnerable window and the critical length. CONCLUSIONS The constructed multi-scale rat ventricle model is able to reproduce both the physiological and the pathological phenomenon in different scales. Evaluation experiments suggest that the apex is the most susceptible area to arrhythmias. The model can be a promising tool for the investigation of arrhythmogenesis and the screening of anti-arrhythmic drugs.
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Affiliation(s)
- Xiangpeng Bi
- College of Computer Science and Technology, Ocean University of China, Qingdao 266100, China
| | - Shugang Zhang
- College of Computer Science and Technology, Ocean University of China, Qingdao 266100, China; High Performance Computing Center, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China.
| | - Huasen Jiang
- College of Computer Science and Technology, Ocean University of China, Qingdao 266100, China
| | - Zhiqiang Wei
- College of Computer Science and Technology, Ocean University of China, Qingdao 266100, China; High Performance Computing Center, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
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Liu Y, Zhang R, Hancox JC, Zhang H. In silico investigation of pro-arrhythmic effects of azithromycin on the human ventricle. Biochem Biophys Rep 2021; 27:101043. [PMID: 34179514 PMCID: PMC8213892 DOI: 10.1016/j.bbrep.2021.101043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 04/08/2021] [Accepted: 06/01/2021] [Indexed: 11/16/2022] Open
Abstract
The macrolide antibiotic azithromycin (AZM) is widely used for respiratory infections and has been suggested to be a possible treatment for the Coronavirus Disease of 2019 (COVID-19). However, AZM-associated QT interval prolongation and arrhythmias have been reported. Integrated mechanistic information on AZM actions on human ventricular excitation and conduction is lacking. Therefore, this study was undertaken to investigate the actions of AZM on ventricular cell and tissue electrical activity. The O'Hara- Virag-Varro-Rudy dynamic (ORd) model of human ventricular cells was modified to incorporate experimental data on the concentration-dependent actions of AZM on multiple ion channels, including INa, ICaL, IKr, IKs, IK1 and INaL in both acute and chronic exposure conditions. In the single cell model, AZM prolonged the action potential duration (APD) in a concentration-dependent manner, which was predominantly attributable to IKr reduction in the acute condition and potentiated INaL in the chronic condition. High concentrations of AZM also increased action potential (AP) triangulation (determined as an increased difference between APD30 and APD90) which is a marker of arrhythmia risk. In the chronic condition, the potentiated INaL caused a modest intracellular Na + concentration accumulation at fast pacing rates. At the 1D tissue level, the AZM-prolonged APD at the cellular level was reflected by an increased QT interval in the simulated pseudo-ECG, consistent with clinical observations. Additionally, AZM reduced the conduction velocity (CV) of APs in the acute condition due to a reduced INa, and it augmented the transmural APD dispersion of the ventricular tissue, which is also pro-arrhythmic. Such actions were markedly augmented when the effects of chronic exposure of AZM were also considered, or with additional IKr block, as may occur with concurrent use of other medications. This study provides insights into the ionic mechanisms by which high concentrations of AZM may modulate ventricular electrophysiology and susceptibility to arrhythmia.
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Affiliation(s)
- Yizhou Liu
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Rai Zhang
- School of Civil, Aerospace and Mechanical Engineering, University of Bristol, United Kingdom
| | - Jules C. Hancox
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
- School of Physiology, Pharmacology and Neuroscience, Cardiovascular Research Laboratories, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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Baracaldo-Santamaría D, Llinás-Caballero K, Corso-Ramirez JM, Restrepo CM, Dominguez-Dominguez CA, Fonseca-Mendoza DJ, Calderon-Ospina CA. Genetic and Molecular Aspects of Drug-Induced QT Interval Prolongation. Int J Mol Sci 2021; 22:8090. [PMID: 34360853 PMCID: PMC8347245 DOI: 10.3390/ijms22158090] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/04/2021] [Accepted: 07/06/2021] [Indexed: 12/22/2022] Open
Abstract
Long QT syndromes can be either acquired or congenital. Drugs are one of the many etiologies that may induce acquired long QT syndrome. In fact, many drugs frequently used in the clinical setting are a known risk factor for a prolonged QT interval, thus increasing the chances of developing torsade de pointes. The molecular mechanisms involved in the prolongation of the QT interval are common to most medications. However, there is considerable inter-individual variability in drug response, thus making the application of personalized medicine a relevant aspect in long QT syndrome, in order to evaluate the risk of every individual from a pharmacogenetic standpoint.
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Affiliation(s)
- Daniela Baracaldo-Santamaría
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia; (D.B.-S.); (J.M.C.-R.); (C.A.D.-D.)
| | - Kevin Llinás-Caballero
- GENIUROS Research Group, Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia; (K.L.-C.); (C.M.R.); (D.J.F.-M.)
- Institute for Immunological Research, University of Cartagena, Cartagena 130014, Colombia
| | - Julián Miguel Corso-Ramirez
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia; (D.B.-S.); (J.M.C.-R.); (C.A.D.-D.)
| | - Carlos Martín Restrepo
- GENIUROS Research Group, Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia; (K.L.-C.); (C.M.R.); (D.J.F.-M.)
| | | | - Dora Janeth Fonseca-Mendoza
- GENIUROS Research Group, Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia; (K.L.-C.); (C.M.R.); (D.J.F.-M.)
| | - Carlos Alberto Calderon-Ospina
- GENIUROS Research Group, Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia; (K.L.-C.); (C.M.R.); (D.J.F.-M.)
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Montnach J, Baró I, Charpentier F, De Waard M, Loussouarn G. Modelling sudden cardiac death risks factors in patients with coronavirus disease of 2019: the hydroxychloroquine and azithromycin case. Europace 2021; 23:1124-1133. [PMID: 34009333 PMCID: PMC8135857 DOI: 10.1093/europace/euab043] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 02/16/2021] [Indexed: 12/23/2022] Open
Abstract
AIMS Coronavirus disease of 2019 (COVID-19) has rapidly become a worldwide pandemic. Many clinical trials have been initiated to fight the disease. Among those, hydroxychloroquine and azithromycin had initially been suggested to improve clinical outcomes. Despite any demonstrated beneficial effects, they are still in use in some countries but have been reported to prolong the QT interval and induce life-threatening arrhythmia. Since a significant proportion of the world population may be treated with such COVID-19 therapies, evaluation of the arrhythmogenic risk of any candidate drug is needed. METHODS AND RESULTS Using the O'Hara-Rudy computer model of human ventricular wedge, we evaluate the arrhythmogenic potential of clinical factors that can further alter repolarization in COVID-19 patients in addition to hydroxychloroquine (HCQ) and azithromycin (AZM) such as tachycardia, hypokalaemia, and subclinical to mild long QT syndrome. Hydroxychloroquine and AZM drugs have little impact on QT duration and do not induce any substrate prone to arrhythmia in COVID-19 patients with normal cardiac repolarization reserve. Nevertheless, in every tested condition in which this reserve is reduced, the model predicts larger electrocardiogram impairments, as with dofetilide. In subclinical conditions, the model suggests that mexiletine limits the deleterious effects of AZM and HCQ. CONCLUSION By studying the HCQ and AZM co-administration case, we show that the easy-to-use O'Hara-Rudy model can be applied to assess the QT-prolongation potential of off-label drugs, beyond HCQ and AZM, in different conditions representative of COVID-19 patients and to evaluate the potential impact of additional drug used to limit the arrhythmogenic risk.
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Affiliation(s)
- Jérôme Montnach
- Université de Nantes, CNRS, INSERM, l’institut du thorax, Nantes F-44000, France
| | - Isabelle Baró
- Université de Nantes, CNRS, INSERM, l’institut du thorax, Nantes F-44000, France
| | - Flavien Charpentier
- Université de Nantes, CNRS, INSERM, l’institut du thorax, Nantes F-44000, France
| | - Michel De Waard
- Université de Nantes, CNRS, INSERM, l’institut du thorax, Nantes F-44000, France
- Laboratory of Excellence, Ion Channels, Science & Therapeutics, Valbonne F-06560, France
| | - Gildas Loussouarn
- Université de Nantes, CNRS, INSERM, l’institut du thorax, Nantes F-44000, France
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Al-Owais MM, Steele DS, Holden AV, Benson AP. Deterministic and Stochastic Cellular Mechanisms Contributing to Carbon Monoxide Induced Ventricular Arrhythmias. Front Pharmacol 2021; 12:651050. [PMID: 33995065 PMCID: PMC8113948 DOI: 10.3389/fphar.2021.651050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 04/12/2021] [Indexed: 11/26/2022] Open
Abstract
Chronic exposure to low levels of Carbon Monoxide is associated with an increased risk of cardiac arrhythmia. Microelectrode recordings from rat and guinea pig single isolated ventricular myocytes exposed to CO releasing molecule CORM-2 and excited at 0.2/s show repolarisation changes that develop over hundreds of seconds: action potential prolongation by delayed repolarisation, EADs, multiple EADs and oscillations around the plateau, leading to irreversible repolarisation failure. The measured direct effects of CO on currents in these cells, and ion channels expressed in mammalian systems showed an increase in prolonged late Na+, and a decrease in the maximal T- and L-type Ca++. peak and late Na+, ultra-rapid delayed, delayed rectifier, and the inward rectifier K+ currents. Incorporation of these CO induced changes in maximal currents in ventricular cell models; (Gattoni et al., J. Physiol., 2016, 594, 4193-4224) (rat) and (Luo and Rudy, Circ. Res., 1994, 74, 1071-1096) (guinea-pig) and human endo-, mid-myo- and epi-cardial (O'Hara et al., PLoS Comput. Biol., 2011, 7, e1002061) models, by changes in maximal ionic conductance reproduces these repolarisation abnormalities. Simulations of cell populations with Gaussian distributions of maximal conductance parameters predict a CO induced increase in APD and its variability. Incorporation of these predicted CO induced conductance changes in human ventricular cell electrophysiology into ventricular tissue and wall models give changes in indices for the probability of the initiation of re-entrant arrhythmia.
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Affiliation(s)
- Moza M. Al-Owais
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
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12
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Li Y, Wang K, Li Q, Hancox JC, Zhang H. Reciprocal interaction between IK1 and If in biological pacemakers: A simulation study. PLoS Comput Biol 2021; 17:e1008177. [PMID: 33690622 PMCID: PMC7984617 DOI: 10.1371/journal.pcbi.1008177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 03/22/2021] [Accepted: 02/17/2021] [Indexed: 11/19/2022] Open
Abstract
Pacemaking dysfunction (PD) may result in heart rhythm disorders, syncope or even death. Current treatment of PD using implanted electronic pacemakers has some limitations, such as finite battery life and the risk of repeated surgery. As such, the biological pacemaker has been proposed as a potential alternative to the electronic pacemaker for PD treatment. Experimentally and computationally, it has been shown that bio-engineered pacemaker cells can be generated from non-rhythmic ventricular myocytes (VMs) by knocking out genes related to the inward rectifier potassium channel current (IK1) or by overexpressing hyperpolarization-activated cyclic nucleotide gated channel genes responsible for the "funny" current (If). However, it is unclear if a bio-engineered pacemaker based on the modification of IK1- and If-related channels simultaneously would enhance the ability and stability of bio-engineered pacemaking action potentials. In this study, the possible mechanism(s) responsible for VMs to generate spontaneous pacemaking activity by regulating IK1 and If density were investigated by a computational approach. Our results showed that there was a reciprocal interaction between IK1 and If in ventricular pacemaker model. The effect of IK1 depression on generating ventricular pacemaker was mono-phasic while that of If augmentation was bi-phasic. A moderate increase of If promoted pacemaking activity but excessive increase of If resulted in a slowdown in the pacemaking rate and even an unstable pacemaking state. The dedicated interplay between IK1 and If in generating stable pacemaking and dysrhythmias was evaluated. Finally, a theoretical analysis in the IK1/If parameter space for generating pacemaking action potentials in different states was provided. In conclusion, to the best of our knowledge, this study provides a wide theoretical insight into understandings for generating stable and robust pacemaker cells from non-pacemaking VMs by the interplay of IK1 and If, which may be helpful in designing engineered biological pacemakers for application purposes.
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Affiliation(s)
- Yacong Li
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Kuanquan Wang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
- * E-mail: (KW); (HZ)
| | - Qince Li
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
- Peng Cheng Laboratory, Shenzhen, China
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, United Kingdom
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Henggui Zhang
- Peng Cheng Laboratory, Shenzhen, China
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
- * E-mail: (KW); (HZ)
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13
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Jæger KH, Wall S, Tveito A. Computational prediction of drug response in short QT syndrome type 1 based on measurements of compound effect in stem cell-derived cardiomyocytes. PLoS Comput Biol 2021; 17:e1008089. [PMID: 33591962 PMCID: PMC7909705 DOI: 10.1371/journal.pcbi.1008089] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 02/26/2021] [Accepted: 12/20/2020] [Indexed: 12/20/2022] Open
Abstract
Short QT (SQT) syndrome is a genetic cardiac disorder characterized by an abbreviated QT interval of the patient's electrocardiogram. The syndrome is associated with increased risk of arrhythmia and sudden cardiac death and can arise from a number of ion channel mutations. Cardiomyocytes derived from induced pluripotent stem cells generated from SQT patients (SQT hiPSC-CMs) provide promising platforms for testing pharmacological treatments directly in human cardiac cells exhibiting mutations specific for the syndrome. However, a difficulty is posed by the relative immaturity of hiPSC-CMs, with the possibility that drug effects observed in SQT hiPSC-CMs could be very different from the corresponding drug effect in vivo. In this paper, we apply a multistep computational procedure for translating measured drug effects from these cells to human QT response. This process first detects drug effects on individual ion channels based on measurements of SQT hiPSC-CMs and then uses these results to estimate the drug effects on ventricular action potentials and QT intervals of adult SQT patients. We find that the procedure is able to identify IC50 values in line with measured values for the four drugs quinidine, ivabradine, ajmaline and mexiletine. In addition, the predicted effect of quinidine on the adult QT interval is in good agreement with measured effects of quinidine for adult patients. Consequently, the computational procedure appears to be a useful tool for helping predicting adult drug responses from pure in vitro measurements of patient derived cell lines.
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MESH Headings
- Action Potentials/drug effects
- Adult
- Ajmaline/pharmacology
- Algorithms
- Anti-Arrhythmia Agents/pharmacology
- Arrhythmias, Cardiac/drug therapy
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/physiopathology
- Cell Line
- Computational Biology
- Drug Evaluation, Preclinical/methods
- Drug Evaluation, Preclinical/statistics & numerical data
- ERG1 Potassium Channel/genetics
- Electrocardiography
- Heart Conduction System/abnormalities
- Heart Conduction System/physiopathology
- Heart Defects, Congenital/drug therapy
- Heart Defects, Congenital/genetics
- Heart Defects, Congenital/physiopathology
- Humans
- In Vitro Techniques
- Induced Pluripotent Stem Cells/drug effects
- Induced Pluripotent Stem Cells/physiology
- Ivabradine/pharmacology
- Mexiletine/pharmacology
- Models, Cardiovascular
- Mutation
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/physiology
- Quinidine/pharmacology
- Translational Research, Biomedical
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Affiliation(s)
| | | | - Aslak Tveito
- Simula Research Laboratory, Oslo, Norway
- Department of Informatics, University of Oslo, Oslo, Norway
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14
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Bai J, Zhu Y, Lo A, Gao M, Lu Y, Zhao J, Zhang H. In Silico Assessment of Class I Antiarrhythmic Drug Effects on Pitx2-Induced Atrial Fibrillation: Insights from Populations of Electrophysiological Models of Human Atrial Cells and Tissues. Int J Mol Sci 2021; 22:1265. [PMID: 33514068 PMCID: PMC7866025 DOI: 10.3390/ijms22031265] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/17/2021] [Accepted: 01/18/2021] [Indexed: 02/07/2023] Open
Abstract
Electrical remodelling as a result of homeodomain transcription factor 2 (Pitx2)-dependent gene regulation was linked to atrial fibrillation (AF) and AF patients with single nucleotide polymorphisms at chromosome 4q25 responded favorably to class I antiarrhythmic drugs (AADs). The possible reasons behind this remain elusive. The purpose of this study was to assess the efficacy of the AADs disopyramide, quinidine, and propafenone on human atrial arrhythmias mediated by Pitx2-induced remodelling, from a single cell to the tissue level, using drug binding models with multi-channel pharmacology. Experimentally calibrated populations of human atrial action po-tential (AP) models in both sinus rhythm (SR) and Pitx2-induced AF conditions were constructed by using two distinct models to represent morphological subtypes of AP. Multi-channel pharmaco-logical effects of disopyramide, quinidine, and propafenone on ionic currents were considered. Simulated results showed that Pitx2-induced remodelling increased maximum upstroke velocity (dVdtmax), and decreased AP duration (APD), conduction velocity (CV), and wavelength (WL). At the concentrations tested in this study, these AADs decreased dVdtmax and CV and prolonged APD in the setting of Pitx2-induced AF. Our findings of alterations in WL indicated that disopyramide may be more effective against Pitx2-induced AF than propafenone and quinidine by prolonging WL.
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Affiliation(s)
- Jieyun Bai
- Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China;
| | - Yijie Zhu
- Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China;
| | - Andy Lo
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand; (A.L.); (J.Z.)
| | - Meng Gao
- Department of Computer Science and Technology, College of Electrical Engineering and Information, Northeast Agricultural University, Harbin 150030, China
| | - Yaosheng Lu
- Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China;
| | - Jichao Zhao
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand; (A.L.); (J.Z.)
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK;
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15
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Benson AP, Stevenson-Cocks HJ, Whittaker DG, White E, Colman MA. Multi-scale approaches for the simulation of cardiac electrophysiology: II - Tissue-level structure and function. Methods 2020; 185:60-81. [PMID: 31988002 DOI: 10.1016/j.ymeth.2020.01.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/15/2019] [Accepted: 01/14/2020] [Indexed: 02/06/2023] Open
Abstract
Computational models of the heart, from cell-level models, through one-, two- and three-dimensional tissue-level simplifications, to biophysically-detailed three-dimensional models of the ventricles, atria or whole heart, allow the simulation of excitation and propagation of this excitation, and have provided remarkable insight into the normal and pathological functioning of the heart. In this article we present equations for modelling cellular excitation (i.e. the cell action potential) from both a phenomenological and a biophysical perspective. Hodgkin-Huxley formalism is discussed, along with the current generation of biophysically-detailed cardiac cell models. Alternative Markovian formulations for modelling ionic currents are also presented. Equations describing propagation of this cellular excitation, through one-, two- and three-dimensional idealised or realistic tissues, are then presented. For all types of model, from cell to tissue, methods for discretisation and integration of the underlying equations are discussed. The article finishes with a discussion of two tissue-level experimental imaging techniques - diffusion tensor magnetic resonance imaging and optical imaging - that can be used to provide data for parameterisation and validation of cell- and tissue-level cardiac models.
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Affiliation(s)
- Alan P Benson
- School of Biomedical Sciences University of Leeds, Leeds LS2 9JT, UK.
| | | | - Dominic G Whittaker
- School of Biomedical Sciences University of Leeds, Leeds LS2 9JT, UK; School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Ed White
- School of Biomedical Sciences University of Leeds, Leeds LS2 9JT, UK
| | - Michael A Colman
- School of Biomedical Sciences University of Leeds, Leeds LS2 9JT, UK
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16
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Luo C, Whittaker DG, Liu T, Wang K, Li Y, He Y, Zhang H. Pharmacotherapeutic Effects of Quinidine on Short QT Syndrome by Using Purkinje-Ventricle Model: A Simulation Study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:2856-2859. [PMID: 31946488 DOI: 10.1109/embc.2019.8857134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AIMS Short QT syndrome (SQTS) arises due to gene mutations leading to accelerated ventricular repolarization, and increased risk of cardiac arrhythmias and sudden cardiac death (SCD). The SQT1, SQT2 and SQT3 variants of the SQTS result from inherited gain-of-function mutations (e.g. N588K, V307L and D172N, respectively) to potassium channels. However, the effective management of SQTS remains a challenge, and is incompletely understood. In this study, computational modelling was used to investigate pharmacotherapeutic effects of selected class I drug quinidine on SQT1, SQT2 and SQT3 variants. METHODS AND RESULTS The biophysically-detailed Stewart et al. model of Purkinje fibre cell action potentials and the ten Tusscher et al. model of ventricular cell action potentials were coupled together into a heterogeneous two-dimensional (2D) tissue model. Previously validated IKr, IKs and IK1 channel formulations for SQT1, SQT2 and SQT3 were incorporated in ventricular cell and tissue models. The channel-blocking effects of quinidine on ionic currents were modelled by using Hill coefficient and IC50 values from the literature. At the 10 μM concentration tested in this study, quinidine effectively prolonged the action potential duration (APD) under all the SQT1, SQT2 and SQT3 conditions. In 2D simulations, quinidine prolonged the ventricular repolarization process and prolonged the QT intervals under all SQTS variants conditions. CONCLUSIONS Our findings provide a rational basis for the pursuit of pharmacotherapeutic agent quinidine in the treatment of all SQTS variants.
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17
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Investigation of the Role of Myocyte Orientations in Cardiac Arrhythmia Using Image-Based Models. Biophys J 2019; 117:2396-2408. [PMID: 31679763 PMCID: PMC6990390 DOI: 10.1016/j.bpj.2019.09.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 09/13/2019] [Accepted: 09/23/2019] [Indexed: 11/24/2022] Open
Abstract
Cardiac electrical excitation-propagation is influenced by myocyte orientations (cellular organization). Quantitatively understanding this relationship presents a significant research challenge, especially during arrhythmias in which excitation patterns become complex. Tissue-scale simulations of cardiac electrophysiology, incorporating both dynamic action potential behavior and image-based myocardial architecture, provide an approach to investigate three-dimensional (3D) propagation of excitation waves in the heart. In this study, we aimed to assess the importance of natural variation in myocyte orientations on cardiac arrhythmogenesis using 3D tissue electrophysiology simulations. Three anatomical models (i.e., describing myocyte orientations) of healthy rat ventricles—obtained using diffusion tensor imaging at 100 μm resolution—were registered to a single biventricular geometry (i.e., a single cardiac shape), in which the myocyte orientations could be represented by each of the diffusion tensor imaging data sets or by an idealized rule-based description. The Fenton-Karma cellular excitation model was modified to reproduce rat ventricular action potential duration restitution to create reaction-diffusion cardiac electrophysiology models. Over 250 3D simulations were performed to investigate the effects of myocyte orientations on the following: 1) ventricular activation, 2) location-dependent arrhythmia induction via rapid pacing, and 3) dynamics of re-entry averaged over multiple episodes. It was shown that 1) myocyte orientation differences manifested themselves in local activation times, but the influence on total activation time was small; 2) differences in myocyte orientations could critically affect the inducibility and persistence of arrhythmias for specific stimulus-location/cycle-length combinations; and 3) myocyte orientations alone could be an important determinant of scroll wave break, although no significant differences were observed in averaged arrhythmia dynamics between the four myocyte orientation scenarios considered. Our results show that myocyte orientations are an important determinant of arrhythmia inducibility, persistence, and scroll wave break. These findings suggest that where specificity is desired (for example, when predicting location-dependent, patient-specific arrhythmia inducibility), subject-specific myocyte orientations may be important.
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18
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Butler A, Zhang Y, Stuart AG, Dempsey CE, Hancox JC. Functional and pharmacological characterization of an S5 domain hERG mutation associated with short QT syndrome. Heliyon 2019; 5:e01429. [PMID: 31049424 PMCID: PMC6479114 DOI: 10.1016/j.heliyon.2019.e01429] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/21/2019] [Accepted: 03/22/2019] [Indexed: 11/18/2022] Open
Abstract
Congenital short QT syndrome (SQTS) is a repolarization disorder characterized by abbreviated QT intervals, atrial and ventricular arrhythmias and a risk of sudden death. This study characterized a missense mutation (I560T) in the S5 domain of the hERG K+ channel that has been associated with variant 1 of the SQTS. Whole cell patch clamp recordings of wild-type (WT) and I560T hERG current (IhERG) were made at 37 °C from hERG expressing HEK 293 cells, and the structural context of the mutation was investigated using a recently reported cryo-EM structure of hERG. Under conventional voltage clamp, the I560T mutation increased IhERG amplitude without altering the voltage-dependence of activation, although it accelerated activation time-course and also slowed deactivation time-course at some voltages. The voltage dependence of IhERG inactivation was positively shifted (by ∼24 mV) and the time-course of inactivation was slowed by the I560T mutation. There was also a modest decrease in K+ over Na+ ion selectivity with the I560T mutation. Under action potential (AP) voltage clamp, the net charge carried by hERG was significantly increased during ventricular, Purkinje fibre and atrial APs, with maximal IhERG also occurring earlier during the plateau phase of ventricular and Purkinje fibre APs. The I560T mutation exerted only a modest effect on quinidine sensitivity of IhERG: the IC50 for mutant IhERG was 2.3 fold that for WT IhERG under conventional voltage clamp. Under AP voltage clamp the inhibitory effect of 1 μM quinidine was largely retained for I560T hERG and the timing of peak I560T IhERG was altered towards that of the WT channel. In both the open channel structure and a closed hERG channel model based on the closely-related EAG structure, I560T side-chains were oriented towards membrane lipid and away from adjacent domains of the channel, contrasting with previous predictions based on homology modelling. In summary, the I560T mutation produces multiple effects on hERG channel operation that result in a gain-of-function that is expected to abbreviate ventricular, atrial and Purkinje fibre repolarization. Quinidine is likely to be of value in offsetting the increase in IhERG and altered IhERG timing during ventricular APs in SQTS with this mutation.
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Affiliation(s)
- Andrew Butler
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
| | - Yihong Zhang
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
- Corresponding author.
| | - A. Graham Stuart
- Bristol Heart Institute, University of Bristol, Bristol, BS2 8HW, United Kingdom
| | - Christopher E. Dempsey
- School of Biochemistry, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
- Bristol Heart Institute, University of Bristol, Bristol, BS2 8HW, United Kingdom
- Corresponding author.
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19
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Hancox JC, Whittaker DG, Zhang H, Stuart AG. Learning from studying very rare cardiac conditions: the example of short QT syndrome. JOURNAL OF CONGENITAL CARDIOLOGY 2019. [DOI: 10.1186/s40949-019-0024-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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20
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Perez Alday EA, Whittaker DG, Benson AP, Colman MA. Effects of Heart Rate and Ventricular Wall Thickness on Non-invasive Mapping: An in silico Study. Front Physiol 2019; 10:308. [PMID: 31024330 PMCID: PMC6460935 DOI: 10.3389/fphys.2019.00308] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 03/07/2019] [Indexed: 01/08/2023] Open
Abstract
Background: Non-invasive cardiac mapping—also known as Electrocardiographic imaging (ECGi)—is a novel, painless and relatively economic method to map the electrical activation and repolarization patterns of the heart, providing a valuable tool for early identification and diagnosis of conduction abnormalities and arrhythmias. Moreover, the ability to obtain information on cardiac electrical activity non-invasively using ECGi provides the potential for a priori information to guide invasive surgical procedures, improving success rates, and reducing procedure time. Previous studies have shown the influence of clinical variables, such as heart rate, heart size, endocardial wall, and body composition on surface electrocardiogram (ECG) measurements. The influence of clinical variables on the ECG variability has provided information on cardiovascular control and its abnormalities in various pathologies. However, the effects of such clinical variables on the Body Surface Potential (BSP) and ECGi maps have yet to be systematically investigated. Methods: In this study we investigated the effects of heart size, intracardiac thickness, and heart rate on BSP and ECGi maps using a previously-developed 3D electrophysiologically-detailed ventricles-torso model. The inverse solution was solved using the three different Tikhonov regularization methods. Results: Through comparison of multiple measures of error/accuracy on the ECGi reconstructions, our results showed that using different heart geometries to solve the forward and inverse problems produced a larger estimated focal excitation location. An increase of ~2 mm in the Euclidean distance error was observed for an increase in the heart size. However, the estimation of the location of focal activity was still able to be obtained. Similarly, a Euclidean distance increase was observed when the order of regularization was reduced. For the case of activation maps reconstructed at the same ectopic focus location but different heart rates, an increase in the errors and Euclidean distance was observed when the heart rate was increased. Conclusions: Non-invasive cardiac mapping can still provide useful information about cardiac activation patterns for the cases when a different geometry is used for the inverse problem compared to the one used for the forward solution; rapid pacing rates can induce order-dependent errors in the accuracy of reconstruction.
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Affiliation(s)
- Erick Andres Perez Alday
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Dominic G Whittaker
- School of Biomedical Science and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Alan P Benson
- School of Biomedical Science and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Michael A Colman
- School of Biomedical Science and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
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21
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Whittaker DG, Hancox JC, Zhang H. In silico Assessment of Pharmacotherapy for Human Atrial Patho-Electrophysiology Associated With hERG-Linked Short QT Syndrome. Front Physiol 2019; 9:1888. [PMID: 30687112 PMCID: PMC6336736 DOI: 10.3389/fphys.2018.01888] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 12/12/2018] [Indexed: 12/19/2022] Open
Abstract
Short QT syndrome variant 1 (SQT1) arises due to gain-of-function mutations to the human Ether-à-go-go-Related Gene (hERG), which encodes the α subunit of channels carrying rapid delayed rectifier potassium current, IKr. In addition to QT interval shortening and ventricular arrhythmias, SQT1 is associated with increased risk of atrial fibrillation (AF), which is often the only clinical presentation. However, the underlying basis of AF and its pharmacological treatment remain incompletely understood in the context of SQT1. In this study, computational modeling was used to investigate mechanisms of human atrial arrhythmogenesis consequent to a SQT1 mutation, as well as pharmacotherapeutic effects of selected class I drugs–disopyramide, quinidine, and propafenone. A Markov chain formulation describing wild type (WT) and N588K-hERG mutant IKr was incorporated into a contemporary human atrial action potential (AP) model, which was integrated into one-dimensional (1D) tissue strands, idealized 2D sheets, and a 3D heterogeneous, anatomical human atria model. Multi-channel pharmacological effects of disopyramide, quinidine, and propafenone, including binding kinetics for IKr/hERG and sodium current, INa, were considered. Heterozygous and homozygous formulations of the N588K-hERG mutation shortened the AP duration (APD) by 53 and 86 ms, respectively, which abbreviated the effective refractory period (ERP) and excitation wavelength in tissue, increasing the lifespan and dominant frequency (DF) of scroll waves in the 3D anatomical human atria. At the concentrations tested in this study, quinidine most effectively prolonged the APD and ERP in the setting of SQT1, followed by disopyramide and propafenone. In 2D simulations, disopyramide and quinidine promoted re-entry termination by increasing the re-entry wavelength, whereas propafenone induced secondary waves which destabilized the re-entrant circuit. In 3D simulations, the DF of re-entry was reduced in a dose-dependent manner for disopyramide and quinidine, and propafenone to a lesser extent. All of the anti-arrhythmic agents promoted pharmacological conversion, most frequently terminating re-entry in the order quinidine > propafenone = disopyramide. Our findings provide further insight into mechanisms of SQT1-related AF and a rational basis for the pursuit of combined IKr and INa block based pharmacological strategies in the treatment of SQT1-linked AF.
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Affiliation(s)
- Dominic G Whittaker
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom.,Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Jules C Hancox
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,Cardiovascular Research Laboratories, Department of Physiology, Pharmacology and Neuroscience, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.,Space Institute of Southern China, Shenzhen, China.,Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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22
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Whittaker DG, Colman MA, Ni H, Hancox JC, Zhang H. Human Atrial Arrhythmogenesis and Sinus Bradycardia in KCNQ1-Linked Short QT Syndrome: Insights From Computational Modelling. Front Physiol 2018; 9:1402. [PMID: 30337886 PMCID: PMC6180159 DOI: 10.3389/fphys.2018.01402] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/14/2018] [Indexed: 11/25/2022] Open
Abstract
Atrial fibrillation (AF) and sinus bradycardia have been reported in patients with short QT syndrome variant 2 (SQT2), which is underlain by gain-of-function mutations in KCNQ1 encoding the α subunit of channels carrying slow delayed rectifier potassium current, IKs. However, the mechanism(s) underlying the increased atrial arrhythmogenesis and impaired cardiac pacemaking activity arising from increased IKs remain unclear. Possible pharmacological interventions of AF in the SQT2 condition also remain to be elucidated. Using computational modelling, we assessed the functional impact of SQT2 mutations on human sinoatrial node (SAN) pacemaking, atrial repolarisation and arrhythmogenesis, and efficacy of the anti-arrhythmic drug quinidine. Markov chain formulations of IKs describing two KCNQ1 mutations – V141M and V307L – were developed from voltage-clamp experimental data and then incorporated into contemporary action potential (AP) models of human atrial and SAN cells, the former of which were integrated into idealised and anatomically detailed tissue models. Both mutations shortened atrial AP duration (APD) through distinct IKs ‘gain-of-function’ mechanisms, whereas SAN pacemaking rate was slowed markedly only by the V141M mutation. Differences in APD restitution steepness influenced re-entry dynamics in tissue – the V141M mutation promoted stationary and stable spiral waves whereas the V307L mutation promoted non-stationary and unstable re-entrant waves. Both mutations shortened tissue excitation wavelength through reduced effective refractory period but not conduction velocity, which served to increase the lifespan of re-entrant excitation in a 3D anatomical human atria model, as well as the dominant frequency (DF), which was higher for the V141M mutation. Quinidine was effective at terminating arrhythmic excitation waves associated with the V307L but not V141M mutation, and reduced the DF in a dose-dependent manner under both mutation conditions. This study provides mechanistic insights into different AF/bradycardia phenotypes in SQT2 and the efficacy of quinidine pharmacotherapy.
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Affiliation(s)
- Dominic G Whittaker
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.,Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Michael A Colman
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Haibo Ni
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Jules C Hancox
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,School of Physiology, Pharmacology and Neuroscience, and Cardiovascular Research Laboratories, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.,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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Butler A, Zhang Y, Stuart AG, Dempsey CE, Hancox JC. Action potential clamp characterization of the S631A hERG mutation associated with short QT syndrome. Physiol Rep 2018; 6:e13845. [PMID: 30175559 PMCID: PMC6119704 DOI: 10.14814/phy2.13845] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/30/2018] [Accepted: 08/02/2018] [Indexed: 11/27/2022] Open
Abstract
The hERG potassium channel is critical to normal repolarization of cardiac action potentials (APs) and loss- and gain-of-function hERG mutations are associated, respectively, with long and short QT syndromes, pathological conditions that can lead to arrhythmias and sudden death. hERG current (IhERG ) exhibits uniquely fast inactivation involving conformational changes to the channel pore. The S631A hERG pore mutation was originally engineered to interrogate hERG channel inactivation, but has very recently been found in a family with short QT syndrome (SQTS). Accordingly, this study characterized the effects of the S631A mutation on IhERG profile during ventricular, atrial, and Purkinje fiber (PF) AP waveforms, using patch clamp recording from hERG expressing HEK 293 cells at 37°C. Under conventional voltage clamp, the current-voltage (I-V) relation for IhERG exhibited a marked right-ward shift in the region of negative slope at positive membrane potentials. Under ventricular AP clamp, the S631A mutation resulted in augmented IhERG , which also peaked much earlier during the AP plateau than did wild-type (WT) IhERG . Instantaneous I-V relations showed a marked positive shift in peak repolarizing current during the ventricular AP in the S631A setting, while the instantaneous conductance-voltage relation showed an earlier and more sustained rise in S631A compared to WT IhERG conductance during ventricular repolarization. Experiments with atrial and PF APs in each case also showed augmented and positively shifted IhERG in the S631A setting, indicating that the S631A mutation is likely to accelerate repolarization in all three cardiac regions. Ventricular AP clamp experiments showed retained effectiveness of the class Ia antiarrhythmic drug quinidine (1 μmol/L) against S631A IhERG . Quinidine is thus likely to be effective in reducing excessively fast repolarization in SQTS resulting from the S631A hERG mutation.
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Affiliation(s)
- Andrew Butler
- School of PhysiologyPharmacology and NeuroscienceMedical Sciences BuildingUniversity WalkBristolUnited Kingdom
| | - Yihong Zhang
- School of PhysiologyPharmacology and NeuroscienceMedical Sciences BuildingUniversity WalkBristolUnited Kingdom
| | - Alan G. Stuart
- Bristol Heart InstituteUniversity of BristolBristolUnited Kingdom
| | | | - Jules C. Hancox
- School of PhysiologyPharmacology and NeuroscienceMedical Sciences BuildingUniversity WalkBristolUnited Kingdom
- Bristol Heart InstituteUniversity of BristolBristolUnited Kingdom
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Hancox JC, Whittaker DG, Du C, Stuart AG, Zhang H. Emerging therapeutic targets in the short QT syndrome. Expert Opin Ther Targets 2018; 22:439-451. [DOI: 10.1080/14728222.2018.1470621] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jules C Hancox
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, United Kingdom
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Dominic G Whittaker
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Chunyun Du
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, United Kingdom
| | - A. Graham Stuart
- Cardiology, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
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