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Mangileva D, Kursanov A, Katsnelson L, Solovyova O. Unsupervised deep network for image texture transformation: Improving the quality of cross-correlation analysis and mechanical vortex visualisation during cardiac fibrillation. Heliyon 2023; 9:e22207. [PMID: 38053873 PMCID: PMC10694166 DOI: 10.1016/j.heliyon.2023.e22207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 10/26/2023] [Accepted: 11/06/2023] [Indexed: 12/07/2023] Open
Abstract
Visualisation of cardiac fibrillation plays a very considerable role in cardiophysiological study and clinical applications. One of the ways to obtain the image of these phenomena is the registration of mechanical displacement fields reflecting the track from electrical activity. In this work, we read these fields using cross-correlation analysis from the video of open pig's epicardium at the start of fibrillation recorded with electrocardiogram. However, the quality of obtained displacement fields remains low due to the weak pixels heterogeneity of the frames. It disables to see more clearly such interesting phenomena as mechanical vortexes that underline the mechanical dysfunction of fibrillation. The applying of chemical or mechanical markers to solve this problem can affect the course of natural processes and falsify the results. Therefore, we developed a novel scheme of an unsupervised deep neural network that is based on the state-of-art positional coding technology for a multilayer perceptron. This network enables to generate a couple of frames with a more heterogeneous pixel texture, that is more suitable for cross-correlation analysis methods, from two consecutive frames. The novel network scheme was tested on synthetic pairs of images with different texture heterogeneity and frequency of displacement fields and also it was compared with different filters on our cardiac tissue image dataset. The testing showed that the displacement fields obtained with our method are closer to the ground truth than those which were computed only with the cross-correlation analysis in low contrast images case where filtering is impossible. Moreover, our model showed the best results comparing with the one of the popular filter CLAHE on our dataset. As a result, using our approach, it was possible to register more clearly a mechanical vortex on the epicardium at the start of fibrillation continuously for several milliseconds for the first time.
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Affiliation(s)
- Daria Mangileva
- Department of Computational Mathematics and Computer Science, Ural Federal University, Ekaterinburg, 620002, Russia
| | - Alexander Kursanov
- Department of Computational Mathematics and Computer Science, Ural Federal University, Ekaterinburg, 620002, Russia
- Institute of Immunology and Physiology, Ural Branch of Russian Sciences Academy, Ekaterinburg, 620049, Russia
| | - Leonid Katsnelson
- Department of Computational Mathematics and Computer Science, Ural Federal University, Ekaterinburg, 620002, Russia
- Institute of Immunology and Physiology, Ural Branch of Russian Sciences Academy, Ekaterinburg, 620049, Russia
| | - Olga Solovyova
- Department of Computational Mathematics and Computer Science, Ural Federal University, Ekaterinburg, 620002, Russia
- Institute of Immunology and Physiology, Ural Branch of Russian Sciences Academy, Ekaterinburg, 620049, Russia
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Kursanov A, Balakina-Vikulova NA, Solovyova O, Panfilov A, Katsnelson LB. In silico analysis of the contribution of cardiomyocyte-fibroblast electromechanical interaction to the arrhythmia. Front Physiol 2023; 14:1123609. [PMID: 36969594 PMCID: PMC10036780 DOI: 10.3389/fphys.2023.1123609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/27/2023] [Indexed: 03/12/2023] Open
Abstract
Although fibroblasts are about 5–10 times smaller than cardiomyocytes, their number in the ventricle is about twice that of cardiomyocytes. The high density of fibroblasts in myocardial tissue leads to a noticeable effect of their electromechanical interaction with cardiomyocytes on the electrical and mechanical functions of the latter. Our work focuses on the analysis of the mechanisms of spontaneous electrical and mechanical activity of the fibroblast-coupled cardiomyocyte during its calcium overload, which occurs in a variety of pathologies, including acute ischemia. For this study, we developed a mathematical model of the electromechanical interaction between cardiomyocyte and fibroblasts and used it to simulate the impact of overloading cardiomyocytes. In contrast to modeling only the electrical interaction between cardiomyocyte and fibroblasts, the following new features emerge in simulations with the model that accounts for both electrical and mechanical coupling and mechano-electrical feedback loops in the interacting cells. First, the activity of mechanosensitive ion channels in the coupled fibroblasts depolarizes their resting potential. Second, this additional depolarization increases the resting potential of the coupled myocyte, thus augmenting its susceptibility to triggered activity. The triggered activity associated with the cardiomyocyte calcium overload manifests itself in the model either as early afterdepolarizations or as extrasystoles, i.e., extra action potentials and extra contractions. Analysis of the model simulations showed that mechanics contribute significantly to the proarrhythmic effects in the cardiomyocyte overloaded with calcium and coupled with fibroblasts, and that mechano-electrical feedback loops in both the cardiomyocyte and fibroblasts play a key role in this phenomenon.
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Affiliation(s)
- Alexander Kursanov
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia
- Laboratory of Mathematical Modeling in Physiology and Medicine Based on Supercomputers, Ural Federal University, Ekaterinburg, Russia
| | - Nathalie A. Balakina-Vikulova
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia
- Laboratory of Mathematical Modeling in Physiology and Medicine Based on Supercomputers, Ural Federal University, Ekaterinburg, Russia
| | - Olga Solovyova
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia
- Laboratory of Mathematical Modeling in Physiology and Medicine Based on Supercomputers, Ural Federal University, Ekaterinburg, Russia
| | - Alexander Panfilov
- Laboratory of Mathematical Modeling in Physiology and Medicine Based on Supercomputers, Ural Federal University, Ekaterinburg, Russia
| | - Leonid B. Katsnelson
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia
- Laboratory of Mathematical Modeling in Physiology and Medicine Based on Supercomputers, Ural Federal University, Ekaterinburg, Russia
- *Correspondence: Leonid B. Katsnelson,
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Mora MT, Zaza A, Trenor B. Insights from an electro-mechanical heart failure cell model: Role of SERCA enhancement on arrhythmogenesis and myocyte contraction. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107350. [PMID: 36689807 DOI: 10.1016/j.cmpb.2023.107350] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/27/2022] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVE Structural and electrical remodeling in heart failure predisposes the heart to ventricular arrhythmias. Computer modeling approaches, used to complement experimental results, can provide a more mechanistic knowledge of the biophysical phenomena underlying cardiac pathologies. Indeed, previous in-silico studies have improved the understanding of the electrical correlates of heart failure involved in arrhythmogenesis; however, information on the crosstalk between electrical activity, intracellular Ca2+ and contraction is still incomplete. This study aims to investigate the electro-mechanical behavior of virtual failing human ventricular myocytes to help in the development of therapies, which should ideally target pump failure and arrhythmias at the same time. METHODS We implemented characteristic remodeling of heart failure with reduced ejection fraction by including reported changes in ionic conductances, sarcomere function and cell structure (e.g. T-tubules disarray). Model parametrization was based on published experimental data and the outcome of simulations was validated against experimentally observed patterns. We focused on two aspects of myocardial dysfunction central in heart failure: altered force-frequency relationship and susceptibility to arrhythmogenic early afterdepolarizations. Because biological variability is a major problem in the generalization of in-silico findings based on a unique set of model parameters, we generated and evaluated a population of models. RESULTS The population-based approach is crucial in robust identification of parameters at the core of abnormalities and in generalizing the outcome of their correction. As compared to non-failing ones, failing myocytes had prolonged repolarization, a higher incidence of early afterdepolarizations, reduced contraction and a shallower force-frequency relationship, all features peculiar of heart failure. Component analysis applied to the model population identified reduced SERCA function as a relevant contributor to most of these derangements, which were largely reverted or diminished by restoration of SERCA function alone. CONCLUSIONS These simulated results encourage the development of strategies comprising SERCA stimulation and highlight the need to evaluate both electrical and mechanical outcomes.
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Affiliation(s)
- Maria Teresa Mora
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Antonio Zaza
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi Milano-Bicocca, Italy; Unità di Fisiologia Cardiovascolare, IRCCs Istituto Auxologico Italiano, Italy
| | - Beatriz Trenor
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain.
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Hurley M, Kaur S, Walton R, Power A, Haïssaguerre M, Bernus O, Ward ML, White E. Endocardial role in arrhythmias induced by acute ventricular stretch and the involvement of Purkinje fibres, in isolated rat hearts. Curr Res Physiol 2023; 6:100098. [PMID: 36814643 PMCID: PMC9939534 DOI: 10.1016/j.crphys.2023.100098] [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: 10/21/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 02/04/2023] Open
Abstract
Purkinje fibres (PFs) play an important role in some ventricular arrhythmias and acute ventricular stretch can evoke mechanically-induced arrhythmias. We tested whether PFs and specifically TRPM4 channels, play a role in these mechanically-induced arrhythmias. Pseudo-ECGs and left ventricular (LV) activation, measured by optical mapping, were recorded in isolated, Langendorff-perfused, rat hearts. The LV endocardial surface was irrigated with experimental agents, via an indwelling catheter. The number and period of ectopic activations was measured during LV lumen inflation via an indwelling fluid-filled balloon (100 μL added over 2 s, maintained for 38 s). Mechanically-induced arrhythmias occurred during balloon inflation: they were multifocal, maximal in the first 5 s and ceased within 20 s. Optical mapping revealed activation patterns indicating PF-mediated and ectopic focal sources. Irrigation of the LV lumen with Lugol solution (IK/I2) for 10s reduced ectopics by 93% (n = 16, P < 0.001); with ablation of endocardial PFs confirmed by histology. Five min irrigation of the LV lumen with 50 μM 9-Phenanthrol, a blocker of TRPM4 channels, reduced ectopics by 39% (n = 15, P < 0.01). Immunohistochemistry confirmed that TRPM4 was more abundant in PFs than myocardium. Our results show that the endocardial surface plays an important role in these mechanically-induced ectopic activations. Ectopic activation patterns indicate a participation of PFs in these arrhythmias, with a potential involvement of TRPM4 channels, shown by the reduction of arrhythmias by 9-Phenanthrol.
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Affiliation(s)
- Miriam Hurley
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Sarbjot Kaur
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Richard Walton
- Université Bordeaux, INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Pessac, Bordeaux, France,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac, Bordeaux, France
| | - Amelia Power
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Michel Haïssaguerre
- Université Bordeaux, INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Pessac, Bordeaux, France,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac, Bordeaux, France,Bordeaux University Hospital (CHU), Electrophysiology and Ablation Unit, Pessac, France
| | - Olivier Bernus
- Université Bordeaux, INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Pessac, Bordeaux, France,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac, Bordeaux, France
| | - Marie-Louise Ward
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Ed White
- School of Biomedical Sciences, University of Leeds, Leeds, UK,Corresponding author. Garstang Building, School of Biomedical Sciences, University of Leeds, LS29JT, Leeds, UK.
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Balakina-Vikulova NA, Katsnelson LB. Integrative Mathematical Model of Electrical, Metabolic and Mechanical Processes in Human Cardiomyocytes. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022070122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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An Investigation of Left Ventricular Valve Disorders and the Mechano-Electric Feedback Using a Synergistic Lumped Parameter Cardiovascular Numerical Model. Bioengineering (Basel) 2022; 9:bioengineering9090454. [PMID: 36135000 PMCID: PMC9495401 DOI: 10.3390/bioengineering9090454] [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: 06/05/2022] [Revised: 08/17/2022] [Accepted: 09/05/2022] [Indexed: 11/17/2022] Open
Abstract
Cardiac diseases and failure make up one of largest contributions to global mortality and significantly detriment the quality of life for millions of others. Disorders in the valves of the left ventricle are a prominent example of heart disease, with prolapse, regurgitation, and stenoses—the three main valve disorders. It is widely known that mitral valve prolapse increases the susceptibility to cardiac arrhythmia. Here, we investigate stenoses and regurgitation of the mitral and aortic valves in the left ventricle using a synergistic low-order numerical model. The model synergy derives from the incorporation of the mechanical, chemical, and electrical elements. As an alternative framework to the time-varying elastance (TVE) method, it allows feedback mechanisms at work in the heart to be considered. The TVE model imposes the ventricular pressure–volume relationship using a periodic function rather than calculating it consistently. Using our synergistic approach, the effects of valve disorders on the mechano-electric-feedback (MEF) are investigated. The MEF is the influence of cellular mechanics on the electrical activity, and significantly contributes to the generation of arrhythmia. We further investigate stenoses and regurgitation of the mitral and aortic valves and their relationship with the MEF and generation of arrhythmia. Mitral valve stenosis is found to increase the sensitivity to arrhythmia-stimulating systolic stretch, and reduces the sensitivity to diastolic stretch. Aortic valve stenosis does not change the sensitivity to arrhythmia-stimulating stretch, and regurgitation reduces it. A key result is found when valve regurgitation is accompanied by diastolic stretch. In the presence of MEF disorder, ectopic beats become far more frequent when accompanied by valve regurgitation. Therefore, arrhythmia resulting from a disorder in the MEF will be more severe when valve regurgitation is present.
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Li Y, Lu W, Hu Q, Cheng C, Lin J, Zhou Y, Chen R, Dai Y, Chen K, Zhang S. Changes of repolarization parameters after left bundle branch area pacing and the association with echocardiographic response in heart failure patients. Front Physiol 2022; 13:912126. [PMID: 35991167 PMCID: PMC9386224 DOI: 10.3389/fphys.2022.912126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 07/04/2022] [Indexed: 12/01/2022] Open
Abstract
Background: Left bundle branch area pacing (LBBAP) has become a safe and effective option for heart failure (HF) patients indicated for cardiac resynchronization therapy (CRT) and/or ventricular pacing, yet the response rate was only 70%. Repolarization parameters were demonstrated to be associated with cardiac mechanics and systolic function. This study aimed to investigate the effects of LBBAP on repolarization parameters and the potential association between those parameters and echocardiographic response. Methods and results: A total of 59 HF patients undergoing successful LBBAP were consecutively included. QTc, Tpeak-Tend (TpTe), and TpTe/QTc were measured before and after the implantation. The results turned out that the dispersion of ventricular repolarization (DVR) improved after LBBAP among the total population. Although trends of repolarization parameters varied according to different QRS configurations at baseline, the post-implant parameters showed no significant difference between groups. The association between repolarization parameters and LBBAP response was then evaluated among patients with wide QRS. Multivariate analysis demonstrated that post-implant TpTe was the independent predictor of LBBAP response (p < 0.05). Receiver operating characteristic analysis indicated an area under the curve of 0.77 (95% CI, 0.60–0.93) with a cutoff value of 81.2 ms (p < 0.01). Patients with post-implant TpTe<81.2 ms had a significantly higher rate of echocardiographic response (93.3 vs. 44.4%, p < 0.01). Further subgroup analysis indicated that the predictive value of post-implant TpTe for LBBAP response was more significant in non-left bundle branch block (LBBB) patients than in LBBB patients. Conclusion: LBBAP improved DVR significantly in HF patients. Post-implant TpTe was associated with the echocardiographic response after LBBAP among patients with wide QRS, especially for non-LBBB patients.
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Affiliation(s)
| | | | | | | | | | | | | | - Yan Dai
- *Correspondence: Yan Dai, ; Keping Chen,
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Kamkin AG, Kamkina OV, Shim AL, Bilichenko A, Mitrokhin VM, Kazansky VE, Filatova TS, Abramochkin D, Mladenov MI. The role of activation of two different sGC binding sites by NO-dependent and NO-independent mechanisms in the regulation of SACs in rat ventricular cardiomyocytes. Physiol Rep 2022; 10:e15246. [PMID: 35384354 PMCID: PMC8981922 DOI: 10.14814/phy2.15246] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 03/09/2022] [Accepted: 03/09/2022] [Indexed: 04/18/2023] Open
Abstract
The mechanoelectrical feedback (MEF) mechanism in the heart that plays a significant role in the occurrence of arrhythmias, involves cation flux through cation nonselective stretch-activated channels (SACs). It is well known that nitric oxide (NO) can act as a regulator of MEF. Here we addressed the possibility of SAC's regulation along NO-dependent and NO-independent pathways, as well as the possibility of S-nitrosylation of SACs. In freshly isolated rat ventricular cardiomyocytes, using the patch-clamp method in whole-cell configuration, inward nonselective stretch-activated cation current ISAC was recorded through SACs, which occurs during dosed cell stretching. NO donor SNAP, α1-subunit of sGC activator BAY41-2272, sGC blocker ODQ, PKG blocker KT5823, PKG activator 8Br-cGMP, and S-nitrosylation blocker ascorbic acid, were employed. We concluded that the physiological concentration of NO in the cell is a necessary condition for the functioning of SACs. An increase in NO due to SNAP in an unstretched cell causes the appearance of a Gd3+ -sensitive nonselective cation current, an analog of ISAC , while in a stretched cell it eliminates ISAC . The NO-independent pathway of sGC activation of α subunit, triggered by BAY41-2272, is also important for the regulation of SACs. Since S-nitrosylation inhibitor completely abolishes ISAC , this mechanism occurs. The application of BAY41-2272 cannot induce ISAC in a nonstretched cell; however, the addition of SNAP on its background activates SACs, rather due to S-nitrosylation. ODQ eliminates ISAC , but SNAP added on the background of stretch increases ISAC in addition to ODQ. This may be a result of the lack of NO as a result of inhibition of NOS by metabolically modified ODQ. KT5823 reduces PKG activity and reduces SACs phosphorylation, leading to an increase in ISAC . 8Br-cGMP reduces ISAC by activating PKG and its phosphorylation. These results demonstrate a significant contribution of S-nitrosylation to the regulation of SACs.
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Affiliation(s)
- Andre G. Kamkin
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Olga V. Kamkina
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Andrey L. Shim
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Andrey Bilichenko
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Vadim M. Mitrokhin
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Viktor E. Kazansky
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Tatiana S. Filatova
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
- Department of Human and Animal PhysiologyLomonosov Moscow State UniversityMoscowRussia
| | - Denis V. Abramochkin
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
- Department of Human and Animal PhysiologyLomonosov Moscow State UniversityMoscowRussia
| | - Mitko I. Mladenov
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
- Faculty of Natural Sciences and MathematicsInstitute of Biology, “Ss. Cyril and Methodius” UniversitySkopjeMacedonia
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Odening KE, van der Linde HJ, Ackerman MJ, Volders PGA, ter Bekke RMA. OUP accepted manuscript. Eur Heart J 2022; 43:3018-3028. [PMID: 35445703 PMCID: PMC9443984 DOI: 10.1093/eurheartj/ehac135] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 02/23/2022] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
An abundance of literature describes physiological and pathological determinants of cardiac performance, building on the principles of excitation–contraction coupling. However, the mutual influencing of excitation–contraction and mechano-electrical feedback in the beating heart, here designated ‘electromechanical reciprocity’, remains poorly recognized clinically, despite the awareness that external and cardiac-internal mechanical stimuli can trigger electrical responses and arrhythmia. This review focuses on electromechanical reciprocity in the long-QT syndrome (LQTS), historically considered a purely electrical disease, but now appreciated as paradigmatic for the understanding of mechano-electrical contributions to arrhythmogenesis in this and other cardiac conditions. Electromechanical dispersion in LQTS is characterized by heterogeneously prolonged ventricular repolarization, besides altered contraction duration and relaxation. Mechanical alterations may deviate from what would be expected from global and regional repolarization abnormalities. Pathological repolarization prolongation outlasts mechanical systole in patients with LQTS, yielding a negative electromechanical window (EMW), which is most pronounced in symptomatic patients. The electromechanical window is a superior and independent arrhythmia-risk predictor compared with the heart rate-corrected QT. A negative EMW implies that the ventricle is deformed—by volume loading during the rapid filling phase—when repolarization is still ongoing. This creates a ‘sensitized’ electromechanical substrate, in which inadvertent electrical or mechanical stimuli such as local after-depolarizations, after-contractions, or dyssynchrony can trigger abnormal impulses. Increased sympathetic-nerve activity and pause-dependent potentiation further exaggerate electromechanical heterogeneities, promoting arrhythmogenesis. Unraveling electromechanical reciprocity advances the understanding of arrhythmia formation in various conditions. Real-time image integration of cardiac electrophysiology and mechanics offers new opportunities to address challenges in arrhythmia management.
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Affiliation(s)
| | - Henk J van der Linde
- Janssen Research & Development, Division of Janssen Pharmaceutica N.V., Beerse, Belgium
| | - Michael J Ackerman
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services (Windland Smith Rice Genetic Heart Rhythm Clinic), Mayo Clinic, Rochester, MN, USA
- Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA
- Department of Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN, USA
| | - Paul G A Volders
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center+, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
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Orini M, Taggart P, Bhuva A, Roberts N, Di Salvo C, Yates M, Badiani S, Van Duijvenboden S, Lloyd G, Smith A, Lambiase PD. Direct in vivo assessment of global and regional mechanoelectric feedback in the intact human heart. Heart Rhythm 2021; 18:1406-1413. [PMID: 33932588 PMCID: PMC8353585 DOI: 10.1016/j.hrthm.2021.04.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023]
Abstract
Background Inhomogeneity of ventricular contraction is associated with sudden cardiac death, but the underlying mechanisms are unclear. Alterations in cardiac contraction impact electrophysiological parameters through mechanoelectric feedback. This has been shown to promote arrhythmias in experimental studies, but its effect in the in vivo human heart is unclear. Objective The purpose of this study was to quantify the impact of regional myocardial deformation provoked by a sudden increase in ventricular loading (aortic occlusion) on human cardiac electrophysiology. Methods In 10 patients undergoing open heart cardiac surgery, left ventricular (LV) afterload was modified by transient aortic occlusion. Simultaneous assessment of whole-heart electrophysiology and LV deformation was performed using an epicardial sock (240 electrodes) and speckle-tracking transesophageal echocardiography. Parameters were matched to 6 American Heart Association LV model segments. The association between changes in regional myocardial segment length and activation-recovery interval (ARI; a conventional surrogate for action potential duration) was studied using mixed-effect models. Results Increased ventricular loading reduced longitudinal shortening (P = .01) and shortened ARI (P = .02), but changes were heterogeneous between cardiac segments. Increased regional longitudinal shortening was associated with ARI shortening (effect size 0.20 [0.01–0.38] ms/%; P = .04) and increased local ARI dispersion (effect size –0.13 [–0.23 to –0.03] ms/%; P = .04). At the whole organ level, increased mechanical dispersion translated into increased dispersion of repolarization (correlation coefficient r = 0.81; P = .01). Conclusion Mechanoelectric feedback can establish a potentially proarrhythmic substrate in the human heart and should be considered to advance our understanding and prevention of cardiac arrhythmias.
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Affiliation(s)
- Michele Orini
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Peter Taggart
- Institute of Cardiovascular Science, University College London, London, United Kingdom.
| | - Anish Bhuva
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Neil Roberts
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Carmelo Di Salvo
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Martin Yates
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Sveeta Badiani
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | | | - Guy Lloyd
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Andrew Smith
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Pier D Lambiase
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
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11
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Korantzopoulos P, Manolis G. Atrial fibrillation induced by appropriate ventricular antitachycardia pacing in an ICD recipient. J Cardiol Cases 2020; 22:94-96. [DOI: 10.1016/j.jccase.2020.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/02/2020] [Accepted: 04/29/2020] [Indexed: 10/24/2022] Open
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Huang HC, Chien KL, Chang YC, Lin LY, Wang J, Liu YB. Increases in repolarization heterogeneity predict left ventricular systolic dysfunction and response to cardiac resynchronization therapy in patients with left bundle branch block. J Cardiovasc Electrophysiol 2020; 31:1770-1778. [PMID: 32275338 DOI: 10.1111/jce.14488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/30/2020] [Accepted: 04/07/2020] [Indexed: 12/23/2022]
Abstract
INTRODUCTION This study aimed to investigate the association between T-wave morphology and impaired left ventricular ejection fraction (LVEF) in patients with complete left bundle branch block (cLBBB), and the predictive value of T-wave morphology for response to cardiac resynchronization therapy (CRT). METHODS AND RESULTS We enrolled 189 patients with cLBBB on electrocardiogram performed between January 2007 and December 2011 who underwent standard echocardiography. Repolarization parameters, including the QRS-to-T angle (TCRT), T-wave morphology dispersion (TMD), T-wave loop area (PL), and T-wave residuum (TWR), were reconstructed from digital standard 12-lead electrocardiograms by T-wave morphology analysis. CRT response was defined as ≥15% reduction in left ventricular end-systolic volume at 12 months after CRT implantation. The clinical outcome endpoint was a composite of heart failure hospitalization, heart transplantation, or death during follow up (mean, 5.8 years). On logistic regression, a higher heart rate, longer QRS duration, increased TMD, and larger TWR were all independently associated with LVEF < 40%. Among 40 patients who underwent CRT, those with a larger TMD (P = .007), larger PL (P = .025), and more negative TCRT (P = .015) had better response to CRT. A large TMD (P = .018) and large PL (P = .003) were also independent predictors of the clinical outcome endpoint. CONCLUSIONS Increases in repolarization heterogeneity in patients with cLBBB are associated with impaired LVEF. A large TMD and large PL may be useful as additional predictors of response to CRT, improving patient selection for CRT.
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Affiliation(s)
- Hui-Chun Huang
- Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Kuo-Liong Chien
- Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.,Institute of Epidemiology, College of Public Health, Taipei, Taiwan
| | - Yi-Chung Chang
- Institute of Communication Engineering, National Taiwan University, Taipei, Taiwan
| | - Lian-Yu Lin
- Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Jui Wang
- Institute of Epidemiology, College of Public Health, Taipei, Taiwan
| | - Yen-Bin Liu
- Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
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13
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Ramírez J, van Duijvenboden S, Young WJ, Orini M, Lambiase PD, Munroe PB, Tinker A. Common Genetic Variants Modulate the Electrocardiographic Tpeak-to-Tend Interval. Am J Hum Genet 2020; 106:764-778. [PMID: 32386560 PMCID: PMC7273524 DOI: 10.1016/j.ajhg.2020.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 04/08/2020] [Indexed: 02/06/2023] Open
Abstract
Sudden cardiac death is responsible for half of all deaths from cardiovascular disease. The analysis of the electrophysiological substrate for arrhythmias is crucial for optimal risk stratification. A prolonged T-peak-to-Tend (Tpe) interval on the electrocardiogram is an independent predictor of increased arrhythmic risk, and Tpe changes with heart rate are even stronger predictors. However, our understanding of the electrophysiological mechanisms supporting these risk factors is limited. We conducted genome-wide association studies (GWASs) for resting Tpe and Tpe response to exercise and recovery in ∼30,000 individuals, followed by replication in independent samples (∼42,000 for resting Tpe and ∼22,000 for Tpe response to exercise and recovery), all from UK Biobank. Fifteen and one single-nucleotide variants for resting Tpe and Tpe response to exercise, respectively, were formally replicated. In a full dataset GWAS, 13 further loci for resting Tpe, 1 for Tpe response to exercise and 1 for Tpe response to exercise were genome-wide significant (p ≤ 5 × 10-8). Sex-specific analyses indicated seven additional loci. In total, we identify 32 loci for resting Tpe, 3 for Tpe response to exercise and 3 for Tpe response to recovery modulating ventricular repolarization, as well as cardiac conduction and contraction. Our findings shed light on the genetic basis of resting Tpe and Tpe response to exercise and recovery, unveiling plausible candidate genes and biological mechanisms underlying ventricular excitability.
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Affiliation(s)
- Julia Ramírez
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK,Institute of Cardiovascular Science, University College London, London WC1E 6BT, UK
| | - Stefan van Duijvenboden
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK,Institute of Cardiovascular Science, University College London, London WC1E 6BT, UK
| | - William J. Young
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK,Barts Heart Centre, St Bartholomew’s Hospital, London EC1A 7BE, UK
| | - Michele Orini
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK,Institute of Cardiovascular Science, University College London, London WC1E 6BT, UK,Barts Heart Centre, St Bartholomew’s Hospital, London EC1A 7BE, UK
| | - Pier D. Lambiase
- Institute of Cardiovascular Science, University College London, London WC1E 6BT, UK,Barts Heart Centre, St Bartholomew’s Hospital, London EC1A 7BE, UK
| | - Patricia B. Munroe
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK,NIHR Barts Cardiovascular Biomedical Research Unit, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK,Corresponding author
| | - Andrew Tinker
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK,NIHR Barts Cardiovascular Biomedical Research Unit, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK,Corresponding author
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14
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Quinn TA, Kohl P. Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm. Physiol Rev 2020; 101:37-92. [PMID: 32380895 DOI: 10.1152/physrev.00036.2019] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.
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Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Peter Kohl
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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15
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Cardiomyocyte calcium handling in health and disease: Insights from in vitro and in silico studies. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 157:54-75. [PMID: 32188566 DOI: 10.1016/j.pbiomolbio.2020.02.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/31/2019] [Accepted: 02/29/2020] [Indexed: 02/07/2023]
Abstract
Calcium (Ca2+) plays a central role in cardiomyocyte excitation-contraction coupling. To ensure an optimal electrical impulse propagation and cardiac contraction, Ca2+ levels are regulated by a variety of Ca2+-handling proteins. In turn, Ca2+ modulates numerous electrophysiological processes. Accordingly, Ca2+-handling abnormalities can promote cardiac arrhythmias via various mechanisms, including the promotion of afterdepolarizations, ion-channel modulation and structural remodeling. In the last 30 years, significant improvements have been made in the computational modeling of cardiomyocyte Ca2+ handling under physiological and pathological conditions. However, numerous questions involving the Ca2+-dependent regulation of different macromolecular complexes, cross-talk between Ca2+-dependent regulatory pathways operating over a wide range of time scales, and bidirectional interactions between electrophysiology and mechanics remain to be addressed by in vitro and in silico studies. A better understanding of disease-specific Ca2+-dependent proarrhythmic mechanisms may facilitate the development of improved therapeutic strategies. In this review, we describe the fundamental mechanisms of cardiomyocyte Ca2+ handling in health and disease, and provide an overview of currently available computational models for cardiomyocyte Ca2+ handling. Finally, we discuss important uncertainties and open questions about cardiomyocyte Ca2+ handling and highlight how synergy between in vitro and in silico studies may help to answer several of these issues.
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16
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Balakina-Vikulova NA, Panfilov A, Solovyova O, Katsnelson LB. Mechano-calcium and mechano-electric feedbacks in the human cardiomyocyte analyzed in a mathematical model. J Physiol Sci 2020; 70:12. [PMID: 32070290 PMCID: PMC7028825 DOI: 10.1186/s12576-020-00741-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/04/2020] [Indexed: 12/11/2022]
Abstract
Experiments on animal hearts (rat, rabbit, guinea pig, etc.) have demonstrated that mechano-calcium feedback (MCF) and mechano-electric feedback (MEF) are very important for myocardial self-regulation because they adjust the cardiomyocyte contractile function to various mechanical loads and to mechanical interactions between heterogeneous myocardial segments in the ventricle walls. In in vitro experiments on these animals, MCF and MEF manifested themselves in several basic classical phenomena (e.g., load dependence, length dependence of isometric twitches, etc.), and in the respective responses of calcium transients and action potentials. However, it is extremely difficult to study simultaneously the electrical, calcium, and mechanical activities of the human heart muscle in vitro. Mathematical modeling is a useful tool for exploring these phenomena. We have developed a novel model to describe electromechanical coupling and mechano-electric feedbacks in the human cardiomyocyte. It combines the ‘ten Tusscher–Panfilov’ electrophysiological model of the human cardiomyocyte with our module of myocardium mechanical activity taken from the ‘Ekaterinburg–Oxford’ model and adjusted to human data. Using it, we simulated isometric and afterloaded twitches and effects of MCF and MEF on excitation–contraction coupling. MCF and MEF were found to affect significantly the duration of the calcium transient and action potential in the human cardiomyocyte model in response to both smaller afterloads as compared to bigger ones and various mechanical interventions applied during isometric and afterloaded twitches.
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Affiliation(s)
- Nathalie A Balakina-Vikulova
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia. .,Ural Federal University, Ekaterinburg, Russia.
| | - Alexander Panfilov
- Ural Federal University, Ekaterinburg, Russia.,Ghent University, Ghent, Belgium
| | - Olga Solovyova
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia.,Ural Federal University, Ekaterinburg, Russia
| | - Leonid B Katsnelson
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia.,Ural Federal University, Ekaterinburg, Russia
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17
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Orini M, Al-Amodi F, Koelsch S, Bailón R. The Effect of Emotional Valence on Ventricular Repolarization Dynamics Is Mediated by Heart Rate Variability: A Study of QT Variability and Music-Induced Emotions. Front Physiol 2019; 10:1465. [PMID: 31849711 PMCID: PMC6895139 DOI: 10.3389/fphys.2019.01465] [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: 09/19/2019] [Accepted: 11/14/2019] [Indexed: 12/20/2022] Open
Abstract
Background Emotions can affect cardiac activity, but their impact on ventricular repolarization variability, an important parameter providing information about cardiac risk and autonomic nervous system activity, is unknown. The beat-to-beat variability of the QT interval (QTV) from the body surface ECG is a non-invasive marker of repolarization variability, which can be decomposed into QTV related to RR variability (QTVrRRV) and QTV unrelated to RRV (QTVuRRV), with the latter thought to be a marker of intrinsic repolarization variability. Aim To determine the effect of emotional valence (pleasant and unpleasant) on repolarization variability in healthy volunteers by means of QTV analysis. Methods 75 individuals (24.5 ± 3.2 years, 36 females) without a history of cardiovascular disease listened to music-excerpts that were either felt as pleasant (n = 6) or unpleasant (n = 6). Excerpts lasted about 90 s and were presented in a random order along with silent intervals (n = 6). QTV and RRV were derived from the ECG and the time-frequency spectrum of RRV, QTV, QTVuRRV and QTVrRRV as well as time-frequency coherence between QTV and RRV were estimated. Analysis was performed in low-frequency (LF), high frequency (HF) and total spectral bands. Results The heart rate-corrected QTV showed a small but significant increase from silence (median 347/interquartile range 31 ms) to listening to music felt as unpleasant (351/30 ms) and pleasant (355/32 ms). The dynamic response of QTV to emotional valence showed a transient phase lasting about 20 s after the onset of each musical excerpt. QTV and RRV were highly correlated in both HF and LF (mean coherence ranging 0.76–0.85). QTV and QTVrRRV decreased during listening to music felt as pleasant and unpleasant with respect to silence and further decreased during listening to music felt as pleasant. QTVuRRV was small and not affected by emotional valence. Conclusion Emotional valence, as evoked by music, has a small but significant effect on QTV and QTVrRRV, but not on QTVuRRV. This suggests that the interaction between emotional valence and ventricular repolarization variability is mediated by cycle length dynamics and not due to intrinsic repolarization variability.
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Affiliation(s)
- Michele Orini
- Institute of Cardiovascular Sciences, University College London, London, United Kingdom.,The William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Faez Al-Amodi
- Institute of Cardiovascular Sciences, University College London, London, United Kingdom
| | - Stefan Koelsch
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
| | - Raquel Bailón
- Aragon Institute for Engineering Research, University of Zaragoza, Zaragoza, Spain.,Center for Biomedical Research in the Network in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
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18
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Elimination of arrhythmogenesis after subtotal resection of congenital cardiac fibroma: a case report. Cardiol Young 2019; 29:701-703. [PMID: 31097046 DOI: 10.1017/s1047951119000180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Subtotal tumour resection is used to treat infants with congenital cardiac fibroma and medication-resistant ventricular arrhythmias; however, complete elimination of arrhythmogenic substrates has been unclear. A 4-month-old male infant with congenital cardiac fibroma and ventricular fibrillation underwent subtotal tumour resection and implantable cardioverter-defibrillator implantation. Five years later, angiography revealed impending compression of the left coronary artery. Elimination of the arrhythmogenic substrate was confirmed and the device was removed successfully.
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19
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Imboden M, de Coulon E, Poulin A, Dellenbach C, Rosset S, Shea H, Rohr S. High-speed mechano-active multielectrode array for investigating rapid stretch effects on cardiac tissue. Nat Commun 2019; 10:834. [PMID: 30783104 PMCID: PMC6381132 DOI: 10.1038/s41467-019-08757-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 01/24/2019] [Indexed: 11/25/2022] Open
Abstract
Systematic investigations of the effects of mechano-electric coupling (MEC) on cellular cardiac electrophysiology lack experimental systems suitable to subject tissues to in-vivo like strain patterns while simultaneously reporting changes in electrical activation. Here, we describe a self-contained motor-less device (mechano-active multielectrode-array, MaMEA) that permits the assessment of impulse conduction along bioengineered strands of cardiac tissue in response to dynamic strain cycles. The device is based on polydimethylsiloxane (PDMS) cell culture substrates patterned with dielectric actuators (DEAs) and compliant gold ion-implanted extracellular electrodes. The DEAs induce uniaxial stretch and compression in defined regions of the PDMS substrate at selectable amplitudes and with rates up to 18 s−1. Conduction along cardiomyocyte strands was found to depend linearly on static strain according to cable theory while, unexpectedly, being completely independent on strain rates. Parallel operation of multiple MaMEAs provides for systematic high-throughput investigations of MEC during spatially patterned mechanical perturbations mimicking in-vivo conditions. While strain is known to affect cardiac electrophysiology, experimental systems to interrogate the effect of rapid strain cycles on cardiac tissue are lacking. Here the authors introduce a multielectrode array that can induce rapid dynamic strain cycles on cardiomyocyte strands and see effects of strain amplitude but not strain rate on impulse conduction.
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Affiliation(s)
- Matthias Imboden
- Soft Transducers Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 2002, Neuchâtel, Switzerland. .,Department of Physiology, University of Bern, Bühlplatz 5, 3012, Bern, Switzerland.
| | - Etienne de Coulon
- Department of Physiology, University of Bern, Bühlplatz 5, 3012, Bern, Switzerland
| | - Alexandre Poulin
- Soft Transducers Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 2002, Neuchâtel, Switzerland
| | - Christian Dellenbach
- Department of Physiology, University of Bern, Bühlplatz 5, 3012, Bern, Switzerland
| | - Samuel Rosset
- Soft Transducers Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 2002, Neuchâtel, Switzerland
| | - Herbert Shea
- Soft Transducers Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 2002, Neuchâtel, Switzerland
| | - Stephan Rohr
- Department of Physiology, University of Bern, Bühlplatz 5, 3012, Bern, Switzerland.
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20
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Abstract
Subtotal tumour resection is used to treat infants with congenital cardiac fibroma and medication-resistant ventricular arrhythmias; however, complete elimination of arrhythmogenic substrates has been unclear. A 4-month-old male infant with congenital cardiac fibroma and ventricular fibrillation underwent subtotal tumour resection and implantable cardioverter-defibrillator implantation. Five years later, angiography revealed impending compression of the left coronary artery. Elimination of the arrhythmogenic substrate was confirmed and the device was removed successfully.
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21
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Loppini A, Gizzi A, Ruiz-Baier R, Cherubini C, Fenton FH, Filippi S. Competing Mechanisms of Stress-Assisted Diffusivity and Stretch-Activated Currents in Cardiac Electromechanics. Front Physiol 2018; 9:1714. [PMID: 30559677 PMCID: PMC6287028 DOI: 10.3389/fphys.2018.01714] [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: 12/18/2017] [Accepted: 11/14/2018] [Indexed: 12/13/2022] Open
Abstract
We numerically investigate the role of mechanical stress in modifying the conductivity properties of cardiac tissue, and also assess the impact of these effects in the solutions generated by computational models for cardiac electromechanics. We follow the recent theoretical framework from Cherubini et al. (2017), proposed in the context of general reaction-diffusion-mechanics systems emerging from multiphysics continuum mechanics and finite elasticity. In the present study, the adapted models are compared against preliminary experimental data of pig right ventricle fluorescence optical mapping. These data contribute to the characterization of the observed inhomogeneity and anisotropy properties that result from mechanical deformation. Our novel approach simultaneously incorporates two mechanisms for mechano-electric feedback (MEF): stretch-activated currents (SAC) and stress-assisted diffusion (SAD); and we also identify their influence into the nonlinear spatiotemporal dynamics. It is found that (i) only specific combinations of the two MEF effects allow proper conduction velocity measurement; (ii) expected heterogeneities and anisotropies are obtained via the novel stress-assisted diffusion mechanisms; (iii) spiral wave meandering and drifting is highly mediated by the applied mechanical loading. We provide an analysis of the intrinsic structure of the nonlinear coupling mechanisms using computational tests conducted with finite element methods. In particular, we compare static and dynamic deformation regimes in the onset of cardiac arrhythmias and address other potential biomedical applications.
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Affiliation(s)
- Alessandro Loppini
- Unit of Nonlinear Physics and Mathematical Modeling, Department of Engineering, University Campus Bio-Medico of Rome, Rome, Italy
| | - Alessio Gizzi
- Unit of Nonlinear Physics and Mathematical Modeling, Department of Engineering, University Campus Bio-Medico of Rome, Rome, Italy
| | - Ricardo Ruiz-Baier
- Mathematical Institute, University of Oxford, Oxford, United Kingdom.,Laboratory of Mathematical Modelling, Institute of Personalized Medicine, Sechenov University, Moscow, Russia
| | - Christian Cherubini
- Unit of Nonlinear Physics and Mathematical Modeling, Department of Engineering, University Campus Bio-Medico of Rome, Rome, Italy.,ICRANet, Pescara, Italy
| | - Flavio H Fenton
- Georgia Institute of Technology, School of Physics, Atlanta, GA, United States
| | - Simonetta Filippi
- Unit of Nonlinear Physics and Mathematical Modeling, Department of Engineering, University Campus Bio-Medico of Rome, Rome, Italy.,ICRANet, Pescara, Italy
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22
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Johnson DM, Antoons G. Arrhythmogenic Mechanisms in Heart Failure: Linking β-Adrenergic Stimulation, Stretch, and Calcium. Front Physiol 2018; 9:1453. [PMID: 30374311 PMCID: PMC6196916 DOI: 10.3389/fphys.2018.01453] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/25/2018] [Indexed: 12/22/2022] Open
Abstract
Heart failure (HF) is associated with elevated sympathetic tone and mechanical load. Both systems activate signaling transduction pathways that increase cardiac output, but eventually become part of the disease process itself leading to further worsening of cardiac function. These alterations can adversely contribute to electrical instability, at least in part due to the modulation of Ca2+ handling at the level of the single cardiac myocyte. The major aim of this review is to provide a definitive overview of the links and cross talk between β-adrenergic stimulation, mechanical load, and arrhythmogenesis in the setting of HF. We will initially review the role of Ca2+ in the induction of both early and delayed afterdepolarizations, the role that β-adrenergic stimulation plays in the initiation of these and how the propensity for these may be altered in HF. We will then go onto reviewing the current data with regards to the link between mechanical load and afterdepolarizations, the associated mechano-sensitivity of the ryanodine receptor and other stretch activated channels that may be associated with HF-associated arrhythmias. Furthermore, we will discuss how alterations in local Ca2+ microdomains during the remodeling process associated the HF may contribute to the increased disposition for β-adrenergic or stretch induced arrhythmogenic triggers. Finally, the potential mechanisms linking β-adrenergic stimulation and mechanical stretch will be clarified, with the aim of finding common modalities of arrhythmogenesis that could be targeted by novel therapeutic agents in the setting of HF.
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Affiliation(s)
- Daniel M Johnson
- Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Gudrun Antoons
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
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23
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Fatkin D, Cox CD, Huttner IG, Martinac B. Is There a Role for Genes in Exercise-Induced Atrial Cardiomyopathy? Heart Lung Circ 2018; 27:1093-1098. [PMID: 29706494 DOI: 10.1016/j.hlc.2018.03.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/21/2018] [Indexed: 02/08/2023]
Abstract
In endurance athletes, prolonged high intensity exercise participation can have deleterious effects on the myocardium with subsequent structural and electrical remodelling. In a subset of athletes, there is a predilection for atrial involvement and the risk of atrial fibrillation (AF) is increased. The mechanisms underpinning exercise-induced atrial cardiomyopathy have yet to be fully elucidated and the contribution of an individual's genetic makeup is unknown. Some athletes may have rare genetic variants that are sufficient to cause AF irrespective of exercise exposure. In AF-causing variant carriers, the additional haemodynamic stress of exercise on atrial structure and function might accelerate or increase the severity of disease. Variants in genes that lack known links to AF may indirectly promote an arrhythmogenic substrate by affecting threshold levels for exercise-induced myocardial damage and remodelling responses, or by effects on AF-associated co-morbidities, sinus node function, and autonomic nervous system tone. Given the exquisite stress-sensitivity of the atria, mechanosensitive ion channels could plausibly have a key role in mediating exercise effects on atrial structure and function. Knowing an athlete's profile of genetic variants may be useful for AF risk stratification and have implications for clinical management. Pre-participation genetic testing may influence sports choices and facilitate AF prevention.
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Affiliation(s)
- Diane Fatkin
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia; Cardiology Department, St. Vincent's Hospital, Sydney, NSW, Australia.
| | - Charles D Cox
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
| | - Inken G Huttner
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Boris Martinac
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
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24
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Rog-Zielinska EA, Peyronnet R. Cardiac mechanics and electrics: It takes two to tango. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:121-123. [PMID: 28962935 DOI: 10.1016/j.pbiomolbio.2017.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Eva A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg-Bad Krozingen, Medical School of the University of Freiburg, Germany; Imperial College London, National Heart and Lung Institute, Heart Science Centre, UK
| | - Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg-Bad Krozingen, Medical School of the University of Freiburg, Germany.
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25
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Orini M, Tinker A, Munroe PB, Lambiase PD. Long-term intra-individual reproducibility of heart rate dynamics during exercise and recovery in the UK Biobank cohort. PLoS One 2017; 12:e0183732. [PMID: 28873397 PMCID: PMC5584807 DOI: 10.1371/journal.pone.0183732] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 08/09/2017] [Indexed: 12/26/2022] Open
Abstract
Background The heart rate (HR) response to exercise provides useful information about the autonomic function and has prognostic value, but its reproducibility over a long period of time, a critical requirement for using it as a clinical biomarker, is undetermined. Aim To determine the intra-individual reproducibility of HR dynamics during sub-maximum exercise and one minute recovery. Methods 1187 individuals from the Cardio physical fitness assessment test of the UK Biobank repeated a standard exercise stress test twice (recall time 34.2 ± 2.8 months) and were prospectively studied. Results 821 individuals complied with inclusion criteria for reproducibility analysis, including peak workload differences between assessments ≤10 W. Intra-individual correlation between HR profile during the first and the second assessment was very high and higher than inter-individual correlation (0.92±0.08 vs 0.87±0.11, p<0.01). Intra-individual correlation of indices describing HR dynamics was: ρ = 0.81 for maximum HR during exercise; ρ = 0.71 for minimum HR during recovery; ρ = 0.70 for HR changes during both exercise and recovery; Intra-individual correlation was higher for these indices of HR dynamics than for resting HR (ρ = 0.64). Bland-Altman plots demonstrated good agreement between HR indices estimated during the first and second assessment. A small but consistent bias was registered for all repeated measurements. The intra-individual consistency of abnormal values was about 60–70%. Conclusions The HR dynamics during exercise and recovery are reproducible over a period of 3 years, with moderate to strong intra-individual reproducibility of abnormal values.
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Affiliation(s)
- Michele Orini
- Institute of Cardiovascular Science, University College London, London, United Kingdom
- Barts Heart Centre, St Bartholomew’s Hospital, London, United Kingdom
- * E-mail:
| | - Andrew Tinker
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Patricia B. Munroe
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Pier D. Lambiase
- Institute of Cardiovascular Science, University College London, London, United Kingdom
- Barts Heart Centre, St Bartholomew’s Hospital, London, United Kingdom
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