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Yamaguchi T. Atrial structural remodeling and atrial fibrillation substrate: A histopathological perspective. J Cardiol 2024:S0914-5087(24)00096-0. [PMID: 38810728 DOI: 10.1016/j.jjcc.2024.05.007] [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] [Received: 04/10/2024] [Revised: 05/16/2024] [Accepted: 05/21/2024] [Indexed: 05/31/2024]
Abstract
Atrial fibrillation (AF) substrate progresses with the advancement of atrial structural remodeling, resulting in AF perpetuation and recurrence. Although fibrosis is considered a hallmark of atrial structural remodeling, the histological background has not been fully elucidated because obtaining atrial specimens is difficult, especially in patients not undergoing open-heart surgery. Bipolar voltage reduction evaluated using electroanatomic mapping during AF ablation is considered a surrogate marker for the progression of structural remodeling; however, histological validation is lacking. We developed an intracardiac echocardiography-guided endomyocardial atrial biopsy technique to evaluate atrial structural remodeling in patients undergoing catheter ablation for nonvalvular AF. The histological factors associated with a decrease in bipolar voltage were interstitial fibrosis, as well as an increase in myocardial intercellular space preceding fibrosis, myofibrillar loss, and a decrease in cardiomyocyte nuclear density, which is a surrogate marker for cardiomyocyte density. Cardiomyocyte hypertrophy is closely associated with a decrease in cardiomyocyte nuclear density, suggesting that hypertrophic changes compensate for cardiomyocyte loss. Electron microscopy also revealed that increased intercellular spaces indicated the leakage of plasma components owing to increased vascular permeability. Additionally, amyloid deposition was observed in 4 % of biopsy cases. Only increased intercellular space and interstitial fibrosis were significantly higher for long-standing persistent AF than for paroxysmal AF and associated with recurrence after AF ablation, suggesting that this interstitial remodeling is the AF substrate. An increase in intercellular space that occurs early in AF formation is a therapeutic target for the AF substrate, which prevents irreversible interstitial degeneration due to collagen accumulation. This endomyocardial atrial biopsy technique will allow the collection of atrial tissue from a wide variety of patients and significantly facilitate the elucidation of the mechanisms of atrial cardiomyopathy, structural remodeling, and AF substrates.
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Perike S, Gonzalez-Gonzalez FJ, Abu-Taha I, Damen FW, Hanft LM, Lizama KS, Aboonabi A, Capote AE, Aguilar-Sanchez Y, Levin B, Han Z, Sridhar A, Grand J, Martin J, Akar JG, Warren CM, Solaro RJ, Sang-Ging O, Darbar D, McDonald KS, Goergen CJ, Wolska BM, Dobrev D, Wehrens XH, McCauley MD. PPP1R12C Promotes Atrial Hypocontractility in Atrial Fibrillation. Circ Res 2023; 133:758-771. [PMID: 37737016 PMCID: PMC10616980 DOI: 10.1161/circresaha.123.322516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023]
Abstract
BACKGROUND Atrial fibrillation (AF)-the most common sustained cardiac arrhythmia-increases thromboembolic stroke risk 5-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function remain unknown. We tested the hypothesis that increased expression of PPP1R12C (protein phosphatase 1 regulatory subunit 12C)-the PP1 (protein phosphatase 1) regulatory subunit targeting MLC2a (atrial myosin light chain 2)-causes hypophosphorylation of MLC2a and results in atrial hypocontractility. METHODS Right atrial appendage tissues were isolated from human patients with AF versus sinus rhythm controls. Western blots, coimmunoprecipitation, and phosphorylation studies were performed to examine how the PP1c (PP1 catalytic subunit)-PPP1R12C interaction causes MLC2a dephosphorylation. In vitro studies of pharmacological MRCK (myotonic dystrophy kinase-related Cdc42-binding kinase) inhibitor (BDP5290) in atrial HL-1 cells were performed to evaluate PP1 holoenzyme activity on MLC2a. Cardiac-specific lentiviral PPP1R12C overexpression was performed in mice to evaluate atrial remodeling with atrial cell shortening assays, echocardiography, and AF inducibility with electrophysiology studies. RESULTS In human patients with AF, PPP1R12C expression was increased 2-fold versus sinus rhythm controls (P=2.0×10-2; n=12 and 12 in each group) with >40% reduction in MLC2a phosphorylation (P=1.4×10-6; n=12 and 12 in each group). PPP1R12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF (P=2.9×10-2 and 6.7×10-3, respectively; n=8 and 8 in each group). In vitro studies utilizing drug BDP5290, which inhibits T560-PPP1R12C phosphorylation, demonstrated increased PPP1R12C binding with both PP1c and MLC2a and dephosphorylation of MLC2a. Mice treated with lentiviral PPP1R12C vector demonstrated a 150% increase in left atrial size versus controls (P=5.0×10-6; n=12, 8, and 12), with reduced atrial strain and atrial ejection fraction. Pacing-induced AF in mice treated with lentiviral PPP1R12C vector was significantly higher than in controls (P=1.8×10-2 and 4.1×10-2, respectively; n=6, 6, and 5). CONCLUSIONS Patients with AF exhibit increased levels of PPP1R12C protein compared with controls. PPP1R12C overexpression in mice increases PP1c targeting to MLC2a and causes MLC2a dephosphorylation, which reduces atrial contractility and increases AF inducibility. These findings suggest that PP1 regulation of sarcomere function at MLC2a is a key determinant of atrial contractility in AF.
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Affiliation(s)
- Srikanth Perike
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
| | - Francisco J. Gonzalez-Gonzalez
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
| | - Issam Abu-Taha
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Germany
| | - Frederick W. Damen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN
| | - Laurin M. Hanft
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia
| | - Ken S. Lizama
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
| | - Anahita Aboonabi
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - Andrielle E. Capote
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - Yuriana Aguilar-Sanchez
- Department of Integrative Physiology and The Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX
| | | | - Zhenbo Han
- Department of Pharmacology and Regenerative Medicine, College of Medicine,University of Illinois at Chicago
| | - Arvind Sridhar
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
| | - Jacob Grand
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
| | | | | | - Chad M. Warren
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - R. John Solaro
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - Ong Sang-Ging
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Pharmacology and Regenerative Medicine, College of Medicine,University of Illinois at Chicago
| | - Dawood Darbar
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
| | - Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia
| | - Craig J. Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN
| | - Beata M. Wolska
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Germany
- Department of Integrative Physiology and The Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX
- Department of Medicine, Montréal Heart Institute and Université de Montréal, Montréal, Canada
| | - Xander H.T. Wehrens
- Department of Integrative Physiology and The Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX
| | - Mark D. McCauley
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL
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Kahle AK, Alken FA, Scherschel K, Meyer C. Prognostic implications of baseline rhythm during catheter ablation for atrial tachycardia. Clin Res Cardiol 2023:10.1007/s00392-023-02292-3. [PMID: 37710016 DOI: 10.1007/s00392-023-02292-3] [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] [Received: 03/13/2023] [Accepted: 08/21/2023] [Indexed: 09/16/2023]
Abstract
BACKGROUND Atrial tachycardias (AT) occurring in patients after previous atrial fibrillation (AF) ablation are increasingly observed in clinical practice. Catheter ablation is the treatment of choice but an optimal workflow to improve patient outcome has not been defined. The purpose of this study was to assess procedural and clinical outcome depending on baseline rhythm at the beginning of AT ablation. METHODS A total of 380 patients (69 (61-75) years, 56.6% male) who underwent catheter ablation for consecutive AT after previous AF ablation were studied. RESULTS At the beginning of the procedure, 140 patients (36.8%) presented in sinus rhythm (SR), 208 (54.7%) with AT and 32 (8.4%) with AF. Patients in SR or with AT underwent shorter procedures (173 (132-213) minutes vs. 161 (120-203) minutes vs. 226 (154-249) minutes; p = 0.002) with more frequent termination to SR (87.9% vs. 81.3% vs. 56.3%; p < 0.001) than patients with AF. Acute procedural success did not differ between patients in SR or with AT but was higher compared to those with AF (96.4% vs. 97.1% vs. 87.5%; p = 0.033). During a follow-up of 290 (181-680) days, patients in baseline SR experienced arrhythmia recurrences less often (36.4% vs. 49.5% vs. 68.8%; p = 0.002) than patients with AT or AF. CONCLUSION Baseline rhythm during AT ablation predicts procedural and clinical outcome. Whereas acute procedural success does not differ between patients in SR or with AT, patients presenting in SR have a more favorable mid-term success rate.
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Affiliation(s)
- Ann-Kathrin Kahle
- Division of Cardiology, Angiology, Intensive Care Medicine, EVK Düsseldorf, cNEP, cardiac Neuro- and Electrophysiology Research Consortium, Kirchfeldstrasse 40, 40217, Düsseldorf, Germany
- Department of Cardiology, Pulmonology, and Vascular Medicine, University Hospital Düsseldorf, Medical Faculty of the Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Fares-Alexander Alken
- Division of Cardiology, Angiology, Intensive Care Medicine, EVK Düsseldorf, cNEP, cardiac Neuro- and Electrophysiology Research Consortium, Kirchfeldstrasse 40, 40217, Düsseldorf, Germany
| | - Katharina Scherschel
- Division of Cardiology, Angiology, Intensive Care Medicine, EVK Düsseldorf, cNEP, cardiac Neuro- and Electrophysiology Research Consortium, Kirchfeldstrasse 40, 40217, Düsseldorf, Germany
- Institute of Neural and Sensory Physiology, cNEP, cardiac Neuro- and Electrophysiology Research Consortium, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Christian Meyer
- Division of Cardiology, Angiology, Intensive Care Medicine, EVK Düsseldorf, cNEP, cardiac Neuro- and Electrophysiology Research Consortium, Kirchfeldstrasse 40, 40217, Düsseldorf, Germany.
- Institute of Neural and Sensory Physiology, cNEP, cardiac Neuro- and Electrophysiology Research Consortium, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany.
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Butova X, Myachina T, Simonova R, Kochurova A, Mukhlynina E, Kopylova G, Shchepkin D, Khokhlova A. The inter-chamber differences in the contractile function between left and right atrial cardiomyocytes in atrial fibrillation in rats. Front Cardiovasc Med 2023; 10:1203093. [PMID: 37608813 PMCID: PMC10440706 DOI: 10.3389/fcvm.2023.1203093] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 07/24/2023] [Indexed: 08/24/2023] Open
Abstract
Introduction The left and right atria (LA, RA) work under different mechanical and metabolic environments that may cause an intrinsic inter-chamber diversity in structure and functional properties between atrial cardiomyocytes (CM) in norm and provoke their different responsiveness to pathological conditions. In this study, we assessed a LA vs. RA difference in CM contractility in paroxysmal atrial fibrillation (AF) and underlying mechanisms. Methods We investigated the contractile function of single isolated CM from LA and RA using a 7-day acetylcholine (ACh)-CaCl2 AF model in rats. We compared auxotonic force, sarcomere length dynamics, cytosolic calcium ([Ca2+]i) transients, intracellular ROS and NO production in LA and RA CM, and analyzed the phosphorylation levels of contractile proteins and actin-myosin interaction using an in vitro motility assay. Results AF resulted in more prominent structural and functional changes in LA myocardium, reducing sarcomere shortening amplitude, and velocity of sarcomere relengthening in mechanically non-loaded LA CM, which was associated with the increased ROS production, decreased NO production, reduced myofibrillar content, and decreased phosphorylation of cardiac myosin binding protein C and troponin I. However, in mechanically loaded CM, AF depressed the auxotonic force amplitude and kinetics in RA CM, while force characteristics were preserved in LA CM. Discussion Thus, inter-atrial differences are increased in paroxysmal AF and affected by the mechanical load that may contribute to the maintenance and progression of AF.
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Affiliation(s)
- Xenia Butova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Tatiana Myachina
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Raisa Simonova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Anastasia Kochurova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Elena Mukhlynina
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
- Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russian Federation
| | - Galina Kopylova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Daniil Shchepkin
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
- Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russian Federation
| | - Anastasia Khokhlova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
- Institute of Physics and Technology, Ural Federal University, Yekaterinburg, Russian Federation
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5
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Perike S, Gonzalez-Gonzalez FJ, Abu-Taha I, Damen FW, Lizama KS, Aboonabi A, Capote AE, Aguilar-Sanchez Y, Levin B, Han Z, Sridhar A, Grand J, Martin J, Akar JG, Warren CM, Solaro RJ, Ong SG, Darbar D, Goergen CJ, Wolska BM, Dobrev D, Wehrens XHT, McCauley MD. Myosin Light Chain Dephosphorylation by PPP1R12C Promotes Atrial Hypocontractility in Atrial Fibrillation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537590. [PMID: 37131731 PMCID: PMC10153354 DOI: 10.1101/2023.04.19.537590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Background Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, increases thromboembolic stroke risk five-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function remain unknown. We tested the hypothesis that increased expression of PPP1R12C, the PP1 regulatory subunit targeting atrial myosin light chain 2 (MLC2a), causes hypophosphorylation of MLC2a and results in atrial hypocontractility. Methods Right atrial appendage tissues were isolated from human AF patients versus sinus rhythm (SR) controls. Western blots, co-immunoprecipitation, and phosphorylation studies were performed to examine how the PP1c-PPP1R12C interaction causes MLC2a de-phosphorylation. In vitro studies of pharmacologic MRCK inhibitor (BDP5290) in atrial HL-1 cells were performed to evaluate PP1 holoenzyme activity on MLC2a. Cardiac-specific lentiviral PPP1R12C overexpression was performed in mice to evaluate atrial remodeling with atrial cell shortening assays, echocardiography, and AF inducibility with EP studies. Results In human patients with AF, PPP1R12C expression was increased two-fold versus SR controls ( P =2.0×10 -2 , n=12,12 in each group) with > 40% reduction in MLC2a phosphorylation ( P =1.4×10 -6 , n=12,12 in each group). PPP1R12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF ( P =2.9×10 -2 and 6.7×10 -3 respectively, n=8,8 in each group). In vitro studies utilizing drug BDP5290, which inhibits T560-PPP1R12C phosphorylation, demonstrated increased PPP1R12C binding with both PP1c and MLC2a, and dephosphorylation of MLC2a. Lenti-12C mice demonstrated a 150% increase in LA size versus controls ( P =5.0×10 -6 , n=12,8,12), with reduced atrial strain and atrial ejection fraction. Pacing-induced AF in Lenti-12C mice was significantly higher than controls ( P =1.8×10 -2 and 4.1×10 -2 respectively, n= 6,6,5). Conclusions AF patients exhibit increased levels of PPP1R12C protein compared to controls. PPP1R12C overexpression in mice increases PP1c targeting to MLC2a and causes MLC2a dephosphorylation, which reduces atrial contractility and increases AF inducibility. These findings suggest that PP1 regulation of sarcomere function at MLC2a is a key determinant of atrial contractility in AF.
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Tarifa C, Vallmitjana A, Jiménez-Sábado V, Marchena M, Llach A, Herraiz-Martínez A, Godoy-Marín H, Nolla-Colomer C, Ginel A, Viñolas X, Montiel J, Ciruela F, Echebarria B, Benítez R, Cinca J, Hove-Madsen L. Spatial Distribution of Calcium Sparks Determines Their Ability to Induce Afterdepolarizations in Human Atrial Myocytes. JACC. BASIC TO TRANSLATIONAL SCIENCE 2022; 8:1-15. [PMID: 36777175 PMCID: PMC9911326 DOI: 10.1016/j.jacbts.2022.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 07/18/2022] [Accepted: 07/18/2022] [Indexed: 11/25/2022]
Abstract
Analysis of the spatio-temporal distribution of calcium sparks showed a preferential increase in sparks near the sarcolemma in atrial myocytes from patients with atrial fibrillation (AF), linked to higher ryanodine receptor (RyR2) phosphorylation at s2808 and lower calsequestrin-2 levels. Mathematical modeling, incorporating modulation of RyR2 gating, showed that only the observed combinations of RyR2 phosphorylation and calsequestrin-2 levels can account for the spatio-temporal distribution of sparks in patients with and without AF. Furthermore, we demonstrate that preferential calcium release near the sarcolemma is key to a higher incidence and amplitude of afterdepolarizations in atrial myocytes from patients with AF.
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Affiliation(s)
- Carmen Tarifa
- Instituto de Investigaciones Biomédicas de Barcelona, IIBB-CSIC, Barcelona, Spain,IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Alexander Vallmitjana
- Department d’Enginyeria de Sistemes, Automàtica i Informàtica Industrial, Universitat Politècnica de Catalunya, Spain
| | - Verónica Jiménez-Sábado
- Instituto de Investigaciones Biomédicas de Barcelona, IIBB-CSIC, Barcelona, Spain,IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares, Madrid, Spain
| | - Miquel Marchena
- Department Physics, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Anna Llach
- IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Adela Herraiz-Martínez
- Instituto de Investigaciones Biomédicas de Barcelona, IIBB-CSIC, Barcelona, Spain,IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Héctor Godoy-Marín
- Department Pathology and Experimental Therapeutics, IDIBELL, University of Barcelona, Barcelona, Spain,Neuroscience Institute, University of Barcelona, Barcelona, Spain
| | - Carme Nolla-Colomer
- Department d’Enginyeria de Sistemes, Automàtica i Informàtica Industrial, Universitat Politècnica de Catalunya, Spain
| | - Antonino Ginel
- Servicio de Cirugía Cardiaca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Xavier Viñolas
- Servicio de Cardiología, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - José Montiel
- Servicio de Cirugía Cardiaca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Francisco Ciruela
- Department Pathology and Experimental Therapeutics, IDIBELL, University of Barcelona, Barcelona, Spain,Neuroscience Institute, University of Barcelona, Barcelona, Spain
| | - Blas Echebarria
- Department Physics, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Raúl Benítez
- Department d’Enginyeria de Sistemes, Automàtica i Informàtica Industrial, Universitat Politècnica de Catalunya, Spain
| | - Juan Cinca
- IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares, Madrid, Spain,Servicio de Cardiología, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Leif Hove-Madsen
- Instituto de Investigaciones Biomédicas de Barcelona, IIBB-CSIC, Barcelona, Spain,IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares, Madrid, Spain,Address for correspondence: Dr Leif Hove-Madsen, Cardiac Rhythm and Contraction Group, Biomedical Research Institute Barcelona, Hospital de la Santa Creu i Sant Pau, St Antoni Ma Claret 167, 08025 Barcelona, Spain.
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Distress-Mediated Remodeling of Cardiac Connexin-43 in a Novel Cell Model for Arrhythmogenic Heart Diseases. Int J Mol Sci 2022; 23:ijms231710174. [PMID: 36077591 PMCID: PMC9456330 DOI: 10.3390/ijms231710174] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
Gap junctions and their expression pattern are essential to robust function of intercellular communication and electrical propagation in cardiomyocytes. In healthy myocytes, the main cardiac gap junction protein connexin-43 (Cx43) is located at the intercalated disc providing a clear direction of signal spreading across the cardiac tissue. Dislocation of Cx43 to lateral membranes has been detected in numerous cardiac diseases leading to slowed conduction and high propensity for the development of arrhythmias. At the cellular level, arrhythmogenic diseases are associated with elevated levels of oxidative distress and gap junction remodeling affecting especially the amount and sarcolemmal distribution of Cx43 expression. So far, a mechanistic link between sustained oxidative distress and altered Cx43 expression has not yet been identified. Here, we propose a novel cell model based on murine induced-pluripotent stem cell-derived cardiomyocytes to investigate subcellular signaling pathways linking cardiomyocyte distress with gap junction remodeling. We tested the new hypothesis that chronic distress, induced by rapid pacing, leads to increased reactive oxygen species, which promotes expression of a micro-RNA, miR-1, specific for the control of Cx43. Our data demonstrate that Cx43 expression is highly sensitive to oxidative distress, leading to reduced expression. This effect can be efficiently prevented by the glutathione peroxidase mimetic ebselen. Moreover, Cx43 expression is tightly regulated by miR-1, which is activated by tachypacing-induced oxidative distress. In light of the high arrhythmogenic potential of altered Cx43 expression, we propose miR-1 as a novel target for pharmacological interventions to prevent the maladaptive remodeling processes during chronic distress in the heart.
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8
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Moral S, Abulí M, Vilardell P, Trucco E, Ballesteros E, Brugada R. Multimodality Imaging in the Study of the Left Atrium. J Clin Med 2022; 11:jcm11102854. [PMID: 35628980 PMCID: PMC9147196 DOI: 10.3390/jcm11102854] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 05/03/2022] [Accepted: 05/16/2022] [Indexed: 02/04/2023] Open
Abstract
The left atrium (LA) plays a vital role in maintaining normal cardiac function. Many cardiac diseases involve the functioning of the LA directly or indirectly. For this reason, the study of the LA has become a priority for today's imaging techniques. Assessment of LA size, function and wall characteristics is routinely performed in cardiac imaging laboratories when a patient undergoes transthoracic echocardiography. However, in cases when the LA is the focus of disease management, such as in atrial fibrillation or left atrial appendage closure, the use of multimodality is critical. Knowledge of the usefulness of each cardiac imaging technique for the study of LA in these patients is crucial in order to choose the most appropriate treatment. While echocardiography is the most widely performed technique for its evaluation and the study of wall deformation analysis is increasingly becoming more reliable, multidetector computed tomography allows a detailed analysis of its anatomy to be carried out in 3D reconstructions that help in the approach to interventional treatments. In addition, the evaluation of the wall by cardiac magnetic resonance imaging or the generation of electroanatomical maps in the electrophysiology room have become essential tools in the treatment of multiple atrial pathologies. For this reason, the goal of this review article is to describe the basic anatomical and functional information of the LA as well as their study employing the main imaging techniques currently available, so that practitioners specializing in cardiac imaging techniques can use these tools in an accurate and clinically useful manner.
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Affiliation(s)
- Sergio Moral
- Cardiology Department, Hospital Universitari Doctor Josep Trueta, 17007 Girona, Spain; (M.A.); (P.V.); (E.T.); (R.B.)
- Correspondence: ; Tel.: +34-972-940-200; Fax: +34-972-940-270
| | - Marc Abulí
- Cardiology Department, Hospital Universitari Doctor Josep Trueta, 17007 Girona, Spain; (M.A.); (P.V.); (E.T.); (R.B.)
| | - Pau Vilardell
- Cardiology Department, Hospital Universitari Doctor Josep Trueta, 17007 Girona, Spain; (M.A.); (P.V.); (E.T.); (R.B.)
| | - Emilce Trucco
- Cardiology Department, Hospital Universitari Doctor Josep Trueta, 17007 Girona, Spain; (M.A.); (P.V.); (E.T.); (R.B.)
| | - Esther Ballesteros
- Dirección Territorial de Radiologia i Medicina Nuclear de Girona, Insititut de Diagnòstic per la Imatge (IDI), Institut D’Investigació Biomèdica de Girona (IDIBGI), 17007 Girona, Spain;
| | - Ramon Brugada
- Cardiology Department, Hospital Universitari Doctor Josep Trueta, 17007 Girona, Spain; (M.A.); (P.V.); (E.T.); (R.B.)
- Cardiovascular Genetics Centre, University of Girona-IDIBGI, 17190 Girona, Spain
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
- Centro Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
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9
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Kaplan AD, Joca HC, Boyman L, Greiser M. Calcium Signaling Silencing in Atrial Fibrillation: Implications for Atrial Sodium Homeostasis. Int J Mol Sci 2021; 22:10513. [PMID: 34638854 PMCID: PMC8508839 DOI: 10.3390/ijms221910513] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/14/2021] [Accepted: 09/14/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia, affecting more than 33 million people worldwide. Despite important advances in therapy, AF's incidence remains high, and treatment often results in recurrence of the arrhythmia. A better understanding of the cellular and molecular changes that (1) trigger AF and (2) occur after the onset of AF will help to identify novel therapeutic targets. Over the past 20 years, a large body of research has shown that intracellular Ca2+ handling is dramatically altered in AF. While some of these changes are arrhythmogenic, other changes counteract cellular arrhythmogenic mechanisms (Calcium Signaling Silencing). The intracellular Na+ concentration ([Na+])i is a key regulator of intracellular Ca2+ handling in cardiac myocytes. Despite its importance in the regulation of intracellular Ca2+ handling, little is known about [Na+]i, its regulation, and how it might be changed in AF. Previous work suggests that there might be increases in the late component of the atrial Na+ current (INa,L) in AF, suggesting that [Na+]i levels might be high in AF. Indeed, a pharmacological blockade of INa,L has been suggested as a treatment for AF. Here, we review calcium signaling silencing and changes in intracellular Na+ homeostasis during AF. We summarize the proposed arrhythmogenic mechanisms associated with increases in INa,L during AF and discuss the evidence from clinical trials that have tested the pharmacological INa,L blocker ranolazine in the treatment of AF.
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Affiliation(s)
- Aaron D. Kaplan
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Humberto C. Joca
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
| | - Maura Greiser
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
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10
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Jost N, Christ T, Magyar J. New Strategies for the Treatment of Atrial Fibrillation. Pharmaceuticals (Basel) 2021; 14:ph14090926. [PMID: 34577626 PMCID: PMC8466466 DOI: 10.3390/ph14090926] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in the clinical practice. It significantly contributes to the morbidity and mortality of the elderly population. Over the past 25-30 years intense effort in basic research has advanced the understanding of the relationship between the pathophysiology of AF and atrial remodelling. Nowadays it is clear that the various forms of atrial remodelling (electrical, contractile and structural) play crucial role in initiating and maintaining the persistent and permanent types of AF. Unlike in ventricular fibrillation, in AF rapid ectopic firing originating from pulmonary veins and re-entry mechanism may induce and maintain (due to atrial remodelling) this complex cardiac arrhythmia. The present review presents and discusses in detail the latest knowledge on the role of remodelling in AF. Special attention is paid to novel concepts and pharmacological targets presumably relevant to the drug treatment of atrial fibrillation.
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Affiliation(s)
- Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, 6725 Szeged, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6725 Szeged, Hungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research Network, 6725 Szeged, Hungary
- Correspondence:
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany;
- DZHK (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
- Department of Sport Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
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11
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Alfuhied A, Kanagala P, McCann GP, Singh A. Multi-modality assessment and role of left atrial function as an imaging biomarker in cardiovascular disease. Int J Cardiovasc Imaging 2021; 37:3355-3369. [PMID: 34169399 PMCID: PMC8557157 DOI: 10.1007/s10554-021-02316-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 06/14/2021] [Indexed: 01/20/2023]
Abstract
The left atrium (LA) plays a vital role in maintaining normal cardiac function. LA volume and function have been utilised as important imaging biomarkers, with their prognostic value demonstrated in multiple cardiac conditions. More recently, there has been a sharp increase in the number of publications utilising LA strain by echocardiography and cardiac magnetic resonance (CMR) imaging. However, little is known about its prognostic value or reproducibility as a technique. In this review, we aim to highlight the conventional and novel imaging techniques available for LA assessment, using echocardiography and CMR, their role as an imaging biomarker in cardiovascular disease, the reproducibility of the techniques and the current limitations to their clinical application. We identify a need for further standardisation of techniques, with establishment of ‘normal’ cut-offs before routine clinical application can be made.
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Affiliation(s)
- Aseel Alfuhied
- Department of Cardiovascular Sciences, University of Leicester, National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, Leicester, UK.,King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Prathap Kanagala
- Department of Cardiovascular Sciences, University of Leicester, National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, Leicester, UK.,Aintree University Hospital, Liverpool, UK
| | - Gerry P McCann
- Department of Cardiovascular Sciences, University of Leicester, National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, Leicester, UK
| | - Anvesha Singh
- Department of Cardiovascular Sciences, University of Leicester, National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, Leicester, UK.
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12
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Comprehensive assessment of left atrial and ventricular remodeling in paroxysmal atrial fibrillation by the cardiovascular magnetic resonance myocardial extracellular volume fraction and feature tracking strain. Sci Rep 2021; 11:10941. [PMID: 34035345 PMCID: PMC8149643 DOI: 10.1038/s41598-021-90117-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/28/2021] [Indexed: 01/18/2023] Open
Abstract
Atrial fibrillation (AF) is a progressive disease that starts with structural or functional changes in the left atrium and left ventricle, and evolves from paroxysmal toward sustained forms. Early detection of structural or functional changes in the left atrium and left ventricle in the paroxysmal stage could be useful for identifying a higher risk of progression to persistent AF and future cardio-cerebrovascular events. The aim of this study was to test the hypothesis that the feature tracking (FT) left atrial (LA) strain and left ventricular (LV) extracellular volume fraction (ECV) derived from cardiovascular magnetic resonance (CMR) could detect early changes in remodeling of the left atrium and ventricle in the paroxysmal AF (PAF) stage. The participants were comprised of 106 PAF patients (age, 66.1 ± 10.7 years; 66% male) who underwent clinical CMR before pulmonary vein isolation and 20 control subjects (age, 68.3 ± 8.6 years; 55% male). The CMR-FT LA strain/phasic function and LV-ECV were compared between the PAF and control groups. The total and passive LA empty fraction (LAEF) and LA strain (corresponding to LA reservoir and conduit function) were decreased in the PAF group as compared to the control group. However, active LAEF (corresponding to the LA booster pump function) did not differ significantly between the PAF group (33.9 ± 10.9%) and control group (37.9 ± 13.3%, p = 0.15), while the active LA strain (corresponding to the LA booster pump function) was significantly decreased in the PAF group (11.4 ± 4.3 vs. 15.2 ± 5.6%, p = 0.002). The LV-ECV was significantly greater in the PAF group (28.7 ± 2.8%) than control group (26.6 ± 2.0%, p = 0.002). In the PAF group, the LV-ECV correlated significantly with the E/e′ and LA volume index. Regarding the LA strain, correlations were seen between the LV-ECV and both the reservoir function and conduit function. CMR-FT LA strain in combination with the LV-ECV in a single clinical study offers a potential imaging marker that identifies LA/LV remodeling including subtle LA booster pump dysfunction undetectable by the conventional booster pump LAEF in the PAF stage.
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13
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Bedford JP, Gerry S, Hatch RA, Rechner I, Young JD, Watkinson PJ. Hospital outcomes associated with new-onset atrial fibrillation during ICU admission: A multicentre competing risks analysis. J Crit Care 2020; 60:72-78. [PMID: 32763777 DOI: 10.1016/j.jcrc.2020.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 05/23/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022]
Abstract
PURPOSE New onset atrial fibrillation (NOAF) in critically ill patients has been associated with increased short-term mortality. Analyses that do not take into account the time-varying nature of NOAF can underestimate its association with hospital outcomes. We investigated the prognostic association of NOAF with hospital outcomes using competing risks methods. MATERIALS AND METHODS We undertook a retrospective cohort study in three general adult intensive care units (ICUs) in the UK from June 2008 to December 2015. We excluded patients with known prior atrial fibrillation or an arrhythmia within four hours of ICU admission. To account for the effect of NOAF on the rate of death per unit time and the rate of discharge alive per unit time we calculated subdistribution hazard ratios (SDHRs). RESULTS Of 7541 patients that fulfilled our inclusion criteria, 831 (11.0%) developed NOAF during their ICU admission. NOAF was associated with an increased duration of hospital stay (CSHR 0.68 (95% CI 0.63-0.73)) and an increased rate of in-hospital death per unit time (CSHR 1.57 (95% CI 1.37-1.1.81)). This resulted in a strong prognostic association with dying in hospital (adjusted SDHR 2.04 (1.79-2.32)). NOAF lasting over 30 min was associated with increased hospital mortality. CONCLUSIONS Using robust methods we demonstrate a stronger prognostic association between NOAF and hospital outcomes than previously reported.
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Affiliation(s)
- Jonathan P Bedford
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
| | - Stephen Gerry
- Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK.
| | - Robert A Hatch
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
| | - Ian Rechner
- Department of Intensive Care Medicine, Royal Berkshire Hospital, Reading, UK.
| | - J Duncan Young
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
| | - Peter J Watkinson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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14
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Liu T, Xiong F, Qi XY, Xiao J, Villeneuve L, Abu-Taha I, Dobrev D, Huang C, Nattel S. Altered calcium handling produces reentry-promoting action potential alternans in atrial fibrillation-remodeled hearts. JCI Insight 2020; 5:133754. [PMID: 32255765 DOI: 10.1172/jci.insight.133754] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 03/25/2020] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) alters atrial cardiomyocyte (ACM) Ca2+ handling, promoting ectopic beat formation. We examined the effects of AF-associated remodeling on Ca2+-related action potential dynamics and consequences for AF susceptibility. AF was maintained electrically in dogs by right atrial (RA) tachypacing. ACMs isolated from AF dogs showed increased Ca2+ release refractoriness, spontaneous Ca2+ spark frequency, and cycle length (CL) threshold for Ca2+ and action potential duration (APD) alternans versus controls. AF increased the in situ CL threshold for Ca2+/APD alternans and spatial dispersion in Ca2+ release recovery kinetics, leading to spatially discordant alternans associated with reentrant rotor formation and susceptibility to AF induction/maintenance. The clinically available agent dantrolene reduced Ca2+ leak and CL threshold for Ca2+/APD alternans in ACMs and AF dog right atrium, while suppressing AF susceptibility; caffeine increased Ca2+ leak and CL threshold for Ca2+/APD alternans in control dog ACMs and RA tissues. In vivo, the atrial repolarization alternans CL threshold was increased in AF versus control, as was AF vulnerability. Intravenous dantrolene restored repolarization alternans threshold and reduced AF vulnerability. Immunoblots showed reduced expression of total and phosphorylated ryanodine receptors and calsequestrin in AF and unchanged phospholamban/SERCA expression. Thus, along with promoting spontaneous ectopy, AF-induced Ca2+ handling abnormalities favor AF by enhancing vulnerability to repolarization alternans, promoting initiation and maintenance of reentrant activity; dantrolene provides a lead molecule to target this mechanism.
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Affiliation(s)
- Tao Liu
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada.,Department of Cardiology, Renmin Hospital of Wuhan University, China.,Cardiovascular Research Institute, Wuhan University, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Feng Xiong
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Xiao-Yan Qi
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Jiening Xiao
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Louis Villeneuve
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Issam Abu-Taha
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Germany
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, China.,Cardiovascular Research Institute, Wuhan University, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Stanley Nattel
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada.,Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Germany.,IHU LIRYC Institute, Fondation Bordeaux Université, Bordeaux, France
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15
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Darlington A, McCauley MD. Atrial Cardiomyopathy: An Unexplored Limb of Virchow's Triad for AF Stroke Prophylaxis. Front Cardiovasc Med 2020; 7:11. [PMID: 32133372 PMCID: PMC7039862 DOI: 10.3389/fcvm.2020.00011] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/27/2020] [Indexed: 01/14/2023] Open
Abstract
The most dreaded complication of atrial fibrillation is stroke, and 70–80% of patients with AF-related stroke die or become disabled. The mechanisms of thromboembolism in AF are multifactorial, with evidence demonstrating that all three criteria of Virchow's triad are satisfied in AF: abnormal stasis of blood, endothelial damage, and hypercoagulability. Mechanistic insights into the latter two limbs have resulted in effective stroke prophylactic therapies (left atrial appendage occlusion and oral anticoagulants); however, despite these advances, there remains an excess of stroke in the AF population that may be due, in part, to a lack of mechanistic understanding of atrial hypocontractility resulting in abnormal stasis of blood within the atrium. These observations support the emerging concept of atrial cardiomyopathy as a cause of stroke. In this Review, we evaluate molecular, translational, and clinical evidence for atrial cardiomyopathy as a cause for stroke from AF, and present a rationale for further investigation of this largely unaddressed limb of Virchow's triad in AF.
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Affiliation(s)
- Ashley Darlington
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States.,Jesse Brown VA Medical Center, Chicago, IL, United States
| | - Mark D McCauley
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States.,Jesse Brown VA Medical Center, Chicago, IL, United States.,Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, United States
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16
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Hsieh CS, Huang PS, Chang SN, Wu CK, Hwang JJ, Chuang EY, Tsai CT. Genome-Wide Copy Number Variation Association Study of Atrial Fibrillation Related Thromboembolic Stroke. J Clin Med 2019; 8:jcm8030332. [PMID: 30857284 PMCID: PMC6463198 DOI: 10.3390/jcm8030332] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/02/2019] [Accepted: 03/05/2019] [Indexed: 12/12/2022] Open
Abstract
Atrial fibrillation (AF) is a common cardiac arrhythmia and is one of the major causes of ischemic stroke. In addition to the clinical factors such as CHADS2 or CHADS2-VASC score, the impact of genetic factors on the risk of thromboembolic stroke in patients with AF has been largely unknown. Single-nucleotide polymorphisms in several genomic regions have been found to be associated with AF. However, these loci do not contribute to all the genetic risks of AF or AF related thromboembolic risks, suggesting that there are other genetic factors or variants not yet discovered. In the human genome, copy number variations (CNVs) could also contribute to disease susceptibility. In the present study, we sought to identify CNVs determining the AF-related thromboembolic risk. Using a genome-wide approach in 109 patients with AF and thromboembolic stroke and 14,666 controls from the Taiwanese general population (Taiwan Biobank), we first identified deletions in chromosomal regions 1p36.32-1p36.33, 5p15.33, 8q24.3 and 19p13.3 and amplifications in 14q11.2 that were significantly associated with AF-related stroke in the Taiwanese population. In these regions, 148 genes were involved, including several microRNAs and long non-recoding RNAs. Using a pathway analysis, we found deletions in GNB1, PRKCZ, and GNG7 genes related to the alpha-adrenergic receptor signaling pathway that play a major role in determining the risk of an AF-related stroke. In conclusion, CNVs may be genetic predictors of a risk of a thromboembolic stroke for patients with AF, possibly pointing to an impaired alpha-adrenergic signaling pathway in the mechanism of AF-related thromboembolism.
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Affiliation(s)
- Chia-Shan Hsieh
- Department of Life Science, Genome and Systems Biology Degree Program, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 106, Taiwan.
- Bioinformatics and Biostatistics Core, Center of Genomic Medicine, National Taiwan University, Taipei 100, Taiwan.
| | - Pang-Shuo Huang
- Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin 640, Taiwan.
| | - Sheng-Nan Chang
- Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin 640, Taiwan.
| | - Cho-Kai Wu
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, No. 1, Section 1, Jen-Ai Road, Taipei 100, Taiwan.
| | - Juey-Jen Hwang
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, No. 1, Section 1, Jen-Ai Road, Taipei 100, Taiwan.
| | - Eric Y Chuang
- Department of Life Science, Genome and Systems Biology Degree Program, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 106, Taiwan.
- Bioinformatics and Biostatistics Core, Center of Genomic Medicine, National Taiwan University, Taipei 100, Taiwan.
| | - Chia-Ti Tsai
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, No. 1, Section 1, Jen-Ai Road, Taipei 100, Taiwan.
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan.
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17
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Westphal S, Stoppe C, Gruenewald M, Bein B, Renner J, Cremer J, Coburn M, Schaelte G, Boening A, Niemann B, Kletzin F, Roesner J, Strouhal U, Reyher C, Laufenberg-Feldmann R, Ferner M, Brandes IF, Bauer M, Kortgen A, Stehr SN, Wittmann M, Baumgarten G, Struck R, Meyer-Treschan T, Kienbaum P, Heringlake M, Schoen J, Sander M, Treskatsch S, Smul T, Wolwender E, Schilling T, Degenhardt F, Franke A, Mucha S, Tittmann L, Kohlhaas M, Fuernau G, Brosteanu O, Hasenclever D, Zacharowski K, Meybohm P. Genome-wide association study of myocardial infarction, atrial fibrillation, acute stroke, acute kidney injury and delirium after cardiac surgery - a sub-analysis of the RIPHeart-Study. BMC Cardiovasc Disord 2019; 19:26. [PMID: 30678657 PMCID: PMC6345037 DOI: 10.1186/s12872-019-1002-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 01/14/2019] [Indexed: 01/01/2023] Open
Abstract
Background The aim of our study was the identification of genetic variants associated with postoperative complications after cardiac surgery. Methods We conducted a prospective, double-blind, multicenter, randomized trial (RIPHeart). We performed a genome-wide association study (GWAS) in 1170 patients of both genders (871 males, 299 females) from the RIPHeart-Study cohort. Patients undergoing non-emergent cardiac surgery were included. Primary endpoint comprises a binary composite complication rate covering atrial fibrillation, delirium, non-fatal myocardial infarction, acute renal failure and/or any new stroke until hospital discharge with a maximum of fourteen days after surgery. Results A total of 547,644 genotyped markers were available for analysis. Following quality control and adjustment for clinical covariate, one SNP reached genome-wide significance (PHLPP2, rs78064607, p = 3.77 × 10− 8) and 139 (adjusted for all other outcomes) SNPs showed promising association with p < 1 × 10− 5 from the GWAS. Conclusions We identified several potential loci, in particular PHLPP2, BBS9, RyR2, DUSP4 and HSPA8, associated with new-onset of atrial fibrillation, delirium, myocardial infarction, acute kidney injury and stroke after cardiac surgery. Trial registration The study was registered with ClinicalTrials.gov NCT01067703, prospectively registered on 11 Feb 2010. Electronic supplementary material The online version of this article (10.1186/s12872-019-1002-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sabine Westphal
- Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt, Germany
| | - Christian Stoppe
- Department of Anaesthesiology, Medical Faculty, RWTH Aachen, University Aachen, Aachen, Germany
| | - Matthias Gruenewald
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Berthold Bein
- Department of Anaesthesiology, Intensive Care Medicine, Emergency Medicine and Pain Therapy, Asklepios Klinik St. Georg, Hamburg, Germany.,Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Jochen Renner
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Jochen Cremer
- Department of Cardiovascular Surgery, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Mark Coburn
- Department of Anaesthesiology, Medical Faculty, RWTH Aachen, University Aachen, Aachen, Germany
| | - Gereon Schaelte
- Department of Anaesthesiology, Medical Faculty, RWTH Aachen, University Aachen, Aachen, Germany
| | - Andreas Boening
- Department of Cardiovascular Surgery, University of Giessen, Giessen, Germany
| | - Bernd Niemann
- Department of Cardiovascular Surgery, University of Giessen, Giessen, Germany
| | - Frank Kletzin
- Clinic of Anaesthesiology and Intensive Care Medicine, University Hospital Rostock, Rostock, Germany
| | - Jan Roesner
- Department of Anaesthesiology and Intensive Care, Suedstadt Hospital Rostock, Rostock, Germany
| | - Ulrich Strouhal
- Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt, Germany
| | - Christian Reyher
- Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt, Germany
| | | | - Marion Ferner
- Department of Anesthesiology, Medical Center of Johannes Gutenberg-University, Mainz, Germany
| | - Ivo F Brandes
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Goettingen, Goettingen, Germany
| | - Martin Bauer
- Department of Anaesthesiology and Intensive Care, Klinikum Region Hannover, Hannover, Germany
| | - Andreas Kortgen
- Department of Anaesthesiology and Intensive Care Medicine and Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Sebastian N Stehr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Maria Wittmann
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| | - Georg Baumgarten
- Department of Anaesthesiology and Intensive Care Medicine, Johanniter Hospital Bonn, Bonn, Germany
| | - Rafael Struck
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| | - Tanja Meyer-Treschan
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Peter Kienbaum
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Matthias Heringlake
- Department of Anaesthesiology and Intensive Care Medicine, University Luebeck, Luebeck, Germany
| | - Julika Schoen
- Department of Anaesthesiology and Intensive Care Medicine, Hospital Neuruppin, Neuruppin, Germany
| | - Michael Sander
- Department of Anaesthesiology and Intensive Care, University of Giessen, Giessen, Germany
| | - Sascha Treskatsch
- Department of Anaesthesiology and Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Campus Charité Mitte, Berlin, Germany
| | - Thorsten Smul
- Department of Anaesthesiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Ewa Wolwender
- Department of Anaesthesiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Thomas Schilling
- Department of Anaesthesiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Frauke Degenhardt
- Institute of Clinical Molecular Biology, Kiel University, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Andre Franke
- Institute of Clinical Molecular Biology, Kiel University, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Soeren Mucha
- Institute of Clinical Molecular Biology, Kiel University, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Lukas Tittmann
- Institute of Clinical Molecular Biology, Kiel University, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Madeline Kohlhaas
- Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt, Germany
| | - Georg Fuernau
- University Heart Center Luebeck, Medical Clinic II (Cardiology/Angiology/Intensive Care Medicine), University Hospital Schleswig-Holstein, Luebeck, Luebeck, Germany
| | - Oana Brosteanu
- Clinical Trial Centre, University Leipzig, Leipzig, Germany
| | - Dirk Hasenclever
- Institute for Medical Informatics, Statistics and Epidemiology, University Leipzig, Leipzig, Germany
| | - Kai Zacharowski
- Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt, Germany
| | - Patrick Meybohm
- Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt, Germany.
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18
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Nakatani Y, Sakamoto T, Yamaguchi Y, Tsujino Y, Kataoka N, Nishida K, Mizumaki K, Kinugawa K. Improvement of Hemodynamic Parameters in Patients With Preserved Left Ventricular Systolic Function by Catheter Ablation of Atrial Fibrillation - A Prospective Study Using Impedance Cardiography. Circ J 2018; 83:75-83. [PMID: 30381696 DOI: 10.1253/circj.cj-18-0911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The effects of catheter ablation for atrial fibrillation (AF) on hemodynamic parameters in patients with preserved left ventricular (LV) systolic function are unclear. Methods and Results: We enrolled 178 patients with AF (paroxysmal, 108; persistent, 70) with preserved LV systolic function who underwent AF ablation. The stroke volume index (SVI) was repeatedly measured using impedance cardiography. Reduced SVI (SVI, <33 mL/m2) was observed in 55% of patients before ablation. In patients with paroxysmal AF, the SVI did not change immediately after ablation (from 35±6 mL/m2to 35±5 mL/m2; P=0.652); however, it increased 1 month after ablation and further increased 6 months after ablation (1 month, 37±6 mL/m2, P<0.001; 6 months, 38±6 mL/m2, P<0.001). In patients with persistent AF, the SVI increased immediately after ablation (from 30±5 mL/m2to 36±6 mL/m2; P<0.001) and further increased until 6 months after ablation (1 month, 37±6 mL, P<0.001; 6 months, 38±5 mL/m2, P<0.001). The baseline SVI was the strongest predictor of the cardiac function improvement with an area under the curve of 0.828. CONCLUSIONS The restoration and maintenance of sinus rhythm using catheter ablation increased the SVI in patients with preserved LV systolic function.
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Affiliation(s)
- Yosuke Nakatani
- Second Department of Internal Medicine, University of Toyama
| | | | | | - Yasushi Tsujino
- Second Department of Internal Medicine, University of Toyama
| | - Naoya Kataoka
- Second Department of Internal Medicine, University of Toyama
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19
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Cheniti G, Vlachos K, Pambrun T, Hooks D, Frontera A, Takigawa M, Bourier F, Kitamura T, Lam A, Martin C, Dumas-Pommier C, Puyo S, Pillois X, Duchateau J, Klotz N, Denis A, Derval N, Jais P, Cochet H, Hocini M, Haissaguerre M, Sacher F. Atrial Fibrillation Mechanisms and Implications for Catheter Ablation. Front Physiol 2018; 9:1458. [PMID: 30459630 PMCID: PMC6232922 DOI: 10.3389/fphys.2018.01458] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 09/26/2018] [Indexed: 01/14/2023] Open
Abstract
AF is a heterogeneous rhythm disorder that is related to a wide spectrum of etiologies and has broad clinical presentations. Mechanisms underlying AF are complex and remain incompletely understood despite extensive research. They associate interactions between triggers, substrate and modulators including ionic and anatomic remodeling, genetic predisposition and neuro-humoral contributors. The pulmonary veins play a key role in the pathogenesis of AF and their isolation is associated to high rates of AF freedom in patients with paroxysmal AF. However, ablation of persistent AF remains less effective, mainly limited by the difficulty to identify the sources sustaining AF. Many theories were advanced to explain the perpetuation of this form of AF, ranging from a single localized focal and reentrant source to diffuse bi-atrial multiple wavelets. Translating these mechanisms to the clinical practice remains challenging and limited by the spatio-temporal resolution of the mapping techniques. AF is driven by focal or reentrant activities that are initially clustered in a relatively limited atrial surface then disseminate everywhere in both atria. Evidence for structural remodeling, mainly represented by atrial fibrosis suggests that reentrant activities using anatomical substrate are the key mechanism sustaining AF. These reentries can be endocardial, epicardial, and intramural which makes them less accessible for mapping and for ablation. Subsequently, early interventions before irreversible remodeling are of major importance. Circumferential pulmonary vein isolation remains the cornerstone of the treatment of AF, regardless of the AF form and of the AF duration. No ablation strategy consistently demonstrated superiority to pulmonary vein isolation in preventing long term recurrences of atrial arrhythmias. Further research that allows accurate identification of the mechanisms underlying AF and efficient ablation should improve the results of PsAF ablation.
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Affiliation(s)
- Ghassen Cheniti
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France.,Cardiology Department, Hopital Sahloul, Universite de Sousse, Sousse, Tunisia
| | - Konstantinos Vlachos
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Thomas Pambrun
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Darren Hooks
- Cardiology Department, Wellington Hospital, Wellington, New Zealand
| | - Antonio Frontera
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Masateru Takigawa
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Felix Bourier
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Takeshi Kitamura
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Anna Lam
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Claire Martin
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | | | - Stephane Puyo
- Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Xavier Pillois
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France
| | - Josselin Duchateau
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Nicolas Klotz
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Arnaud Denis
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Nicolas Derval
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Pierre Jais
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Hubert Cochet
- Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France.,Department of Cardiovascular Imaging, Hopital Haut Leveque, Bordeaux, France
| | - Meleze Hocini
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Michel Haissaguerre
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Frederic Sacher
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
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20
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Denham NC, Pearman CM, Caldwell JL, Madders GWP, Eisner DA, Trafford AW, Dibb KM. Calcium in the Pathophysiology of Atrial Fibrillation and Heart Failure. Front Physiol 2018; 9:1380. [PMID: 30337881 PMCID: PMC6180171 DOI: 10.3389/fphys.2018.01380] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 09/11/2018] [Indexed: 12/20/2022] Open
Abstract
Atrial fibrillation (AF) is commonly associated with heart failure. A bidirectional relationship exists between the two-AF exacerbates heart failure causing a significant increase in heart failure symptoms, admissions to hospital and cardiovascular death, while pathological remodeling of the atria as a result of heart failure increases the risk of AF. A comprehensive understanding of the pathophysiology of AF is essential if we are to break this vicious circle. In this review, the latest evidence will be presented showing a fundamental role for calcium in both the induction and maintenance of AF. After outlining atrial electrophysiology and calcium handling, the role of calcium-dependent afterdepolarizations and atrial repolarization alternans in triggering AF will be considered. The atrial response to rapid stimulation will be discussed, including the short-term protection from calcium overload in the form of calcium signaling silencing and the eventual progression to diastolic calcium leak causing afterdepolarizations and the development of an electrical substrate that perpetuates AF. The role of calcium in the bidirectional relationship between heart failure and AF will then be covered. The effects of heart failure on atrial calcium handling that promote AF will be reviewed, including effects on both atrial myocytes and the pulmonary veins, before the aspects of AF which exacerbate heart failure are discussed. Finally, the limitations of human and animal studies will be explored allowing contextualization of what are sometimes discordant results.
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Affiliation(s)
- Nathan C. Denham
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | | | | | | | | | | | - Katharine M. Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
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21
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22
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Avula UMR, Noonavath M, Wan E. Gender Differences in Atrial Fibrillation. GENDER AND THE GENOME 2017. [DOI: 10.1089/gg.2016.0002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Uma Mahesh R. Avula
- Department of Medicine, Division of Cardiology, Columbia University, New York, New York
| | - Meghana Noonavath
- Department of Medicine, Division of Cardiology, Columbia University, New York, New York
| | - Elaine Wan
- Department of Medicine, Division of Cardiology, Columbia University, New York, New York
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23
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Avula U, Noonavath M, Wan E. Review Article: Gender Differences in Atrial Fibrillation. GENDER AND THE GENOME 2017. [DOI: 10.1177/247028971700100101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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24
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Left Atrial Reverse Remodeling. JACC Cardiovasc Imaging 2017; 10:65-77. [DOI: 10.1016/j.jcmg.2016.11.003] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/31/2016] [Accepted: 11/03/2016] [Indexed: 12/12/2022]
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25
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Cañón S, Caballero R, Herraiz-Martínez A, Pérez-Hernández M, López B, Atienza F, Jalife J, Hove-Madsen L, Delpón E, Bernad A. miR-208b upregulation interferes with calcium handling in HL-1 atrial myocytes: Implications in human chronic atrial fibrillation. J Mol Cell Cardiol 2016; 99:162-173. [PMID: 27545043 DOI: 10.1016/j.yjmcc.2016.08.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 07/29/2016] [Accepted: 08/17/2016] [Indexed: 01/14/2023]
Abstract
MicroRNAs (miR) have considerable potential as therapeutic tools in cardiac diseases. Alterations in atrial miR are involved in the development of atrial fibrillation (AF), but the molecular mechanism underlying their contribution to atrial remodeling in chronic atrial fibrillation (CAF) is only partially understood. Here we used miR array to analyze the miR profile of atrial biopsies from sinus rhythm (SR) and CAF patients. qRT-PCR identified a distinctive CAF-miR signature and described conserved miR-208b upregulation in human and ovine AF atrial tissue. We used bioinformatics analysis to predict genes and signaling pathways as putative miR-208b targets, which highlighted genes from the cardiac muscle gene program and from canonical WNT, gap-junction and Ca2+ signaling networks. Results from analysis of miR-208b-overexpressing HL-1 atrial myocytes and from myocytes isolated from CAF patients showed that aberrant miR-208b levels reduced the expression and function of L-type Ca2+ channel subunits (CACNA1C and CACNB2) as well as the sarcoplasmic reticulum-Ca2+ pump SERCA2. These findings clearly pointed to CAF-specific upregulated miR-208b as an important mediator in Ca2+ handling impairment during atrial remodeling.
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Affiliation(s)
- Susana Cañón
- Cardiovascular Development and Repair Department, Spanish National Cardiovascular Research Center (CNIC), Madrid, Spain; Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology, School of Medicine, Universidad Complutense, 28040 Madrid, Spain
| | - Adela Herraiz-Martínez
- Cardiovascular Research Centre, CSIC-ICCC, Barcelona, Spain; Instituto de Investigación Biomédica Sant Pau, Hospital de la Santa Creu y Sant Pau, Barcelona, Spain
| | - Marta Pérez-Hernández
- Department of Pharmacology, School of Medicine, Universidad Complutense, 28040 Madrid, Spain
| | - Begoña López
- Program for Cardiovascular Diseases, Centre for Applied Medical Research, University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Felipe Atienza
- Cardiology Department, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - José Jalife
- Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA; Area of Myocardial Pathophysiology, Spanish National Cardiovascular Research Center (CNIC), Madrid, Spain
| | - Leif Hove-Madsen
- Cardiovascular Research Centre, CSIC-ICCC, Barcelona, Spain; Instituto de Investigación Biomédica Sant Pau, Hospital de la Santa Creu y Sant Pau, Barcelona, Spain
| | - Eva Delpón
- Department of Pharmacology, School of Medicine, Universidad Complutense, 28040 Madrid, Spain
| | - Antonio Bernad
- Cardiovascular Development and Repair Department, Spanish National Cardiovascular Research Center (CNIC), Madrid, Spain; Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.
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26
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Wasson S, Reddy HK, Dohrmann ML. Current Perspectives of Electrical Remodeling and Its Therapeutic Implications. J Cardiovasc Pharmacol Ther 2016; 9:129-44. [PMID: 15309249 DOI: 10.1177/107424840400900208] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Electrical remodeling involves alterations in the electrophysiologic milieu of myocardium in various disease states, such as ventricular hypertrophy, heart failure, atrial tachyarrhythmias, myocardial ischemia, and infarction that are associated with cardiac arrhythmias. Although research in this area dates back to early part of the 19th century, we still lack the exact knowledge of ionic remodeling, the role of various genes and channel proteins, and their relevance for the newer antiarrhythmic therapies. Structural remodeling may also have an impact on the electrical remodeling process, although differences in both structural and electrical remodeling are associated with different disease states. Various electrophysiologic, cellular, and structural alterations, including anisotropic conduction, increased intracellular calcium levels, and gap junction remodeling predispose to increased dispersion of action potential duration and refractoriness. This constitutes a favorable substrate for early and late afterdepolarizations and reentrant arrhythmias. Studying the role of ionic remodeling in the initiation and propagation of cardiac arrhythmias has significant relevance for developing newer antiarrhythmic therapies, for identifying patients at risk of developing fatal arrhythmias, and for implementing effective preventive measures. Further research is required to understand the specific effects of individual ion channel remodeling, to understand the signal transduction mechanisms, and to address whether detrimental effects of electrical remodeling can be altered.
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Affiliation(s)
- Sanjeev Wasson
- Division of Cardiology, University of Missouri Hospital, Columbia, Missouri 65212, USA
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27
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Ali S, Ugwu J, Kanjwal Y. A Stunning Left Atrial Appendage Thrombus. Cardiology 2016; 134:394-7. [PMID: 27111448 DOI: 10.1159/000444166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 01/20/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Left atrial appendage thrombus formation is a known major complication of atrial fibrillation and atrial flutter which increases the risk of embolism and stroke. This risk of thrombosis is greatly increased with a lack of anticoagulation. After conversion to a normal sinus rhythm in these arrhythmias, the risk of thrombus formation in the left atrium persists through a phenomenon termed atrial myocardial stunning. CASE We present the case of a patient who previously underwent successful pulmonary vein isolation and was found to be in typical isthmus-dependent atrial flutter with a questionable recurrence of atrial fibrillation. The decision was made to return for atrial flutter ablation and for evaluation of prior pulmonary vein isolation. Initially, a transesophageal echocardiogram showed a normal ejection fraction, biatrial enlargement and no left atrial appendage thrombus. Ablation of the cavotricuspid isthmus was successfully accomplished with documented bidirectional block. A transesophageal echocardiogram probe was still in place prior to planned transseptal puncture for the evaluation of pulmonary veins. A large thrombus was now observed filling the left atrial appendage. Conclusion and Objective: Atrial stunning is a transient atrial contractile dysfunction that occurs whether sinus rhythm is restored spontaneously, electrically, pharmacologically or by ablation. We know after conversion that there is higher propensity to increased spontaneous echogenic contrast and decreased velocities; however, we do not have documented knowledge of exactly how soon after the conversion to a sinus rhythm a thrombus may be seen. We demonstrate a case of acute left atrial appendage thrombus formation immediately following the successful ablation of isthmus-dependent atrial flutter. Our report validates the belief that strategies of not interrupting anticoagulation prior to the conversion of these arrhythmias should be implemented.
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Affiliation(s)
- Sajid Ali
- Mercy St. Vincent Hospital and Medical Center, Toledo, Ohio, USA
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28
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Mesubi OO, Anderson ME. Atrial remodelling in atrial fibrillation: CaMKII as a nodal proarrhythmic signal. Cardiovasc Res 2016; 109:542-57. [PMID: 26762270 DOI: 10.1093/cvr/cvw002] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/05/2016] [Indexed: 01/10/2023] Open
Abstract
CaMKII is a serine-threonine protein kinase that is abundant in myocardium. Emergent evidence suggests that CaMKII may play an important role in promoting atrial fibrillation (AF) by targeting a diverse array of proteins involved in membrane excitability, cell survival, calcium homeostasis, matrix remodelling, inflammation, and metabolism. Furthermore, CaMKII inhibition appears to protect against AF in animal models and correct proarrhythmic, defective intracellular Ca(2+) homeostasis in fibrillating human atrial cells. This review considers current concepts and evidence from animal and human studies on the role of CaMKII in AF.
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Affiliation(s)
- Olurotimi O Mesubi
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Medicine, The Johns Hopkins University School of Medicine, 1830 E. Monument Street, Suite 9026, Baltimore, MD 21287, USA
| | - Mark E Anderson
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Medicine, The Johns Hopkins University School of Medicine, 1830 E. Monument Street, Suite 9026, Baltimore, MD 21287, USA Department of Physiology and the Program in Cellular and Molecular Medicine, The Johns Hopkins School of Medicine, Baltimore, MD, USA
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29
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Müller P, Maier J, Dietrich JW, Barth S, Griese DP, Schiedat F, Szöllösi A, Halbfass P, Nentwich K, Roos M, Krug J, Schade A, Schmitt R, Mügge A, Deneke T. Association between left atrial low-voltage area, serum apoptosis, and fibrosis biomarkers and incidence of silent cerebral events after catheter ablation of atrial fibrillation. J Interv Card Electrophysiol 2015; 44:55-62. [DOI: 10.1007/s10840-015-0020-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 05/25/2015] [Indexed: 10/23/2022]
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30
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Wolke C, Bukowska A, Goette A, Lendeckel U. Redox control of cardiac remodeling in atrial fibrillation. Biochim Biophys Acta Gen Subj 2014; 1850:1555-65. [PMID: 25513966 DOI: 10.1016/j.bbagen.2014.12.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/04/2014] [Accepted: 12/09/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is a potential cause of thromboembolic events. AF induces significant changes in the electrophysiological properties of atrial myocytes and causes alterations in the structure, metabolism, and function of the atrial tissue. The molecular basis for the development of structural atrial remodeling of fibrillating human atria is still not fully understood. However, increased production of reactive oxygen or nitrogen species (ROS/RNS) and the activation of specific redox-sensitive signaling pathways observed both in patients with and animal models of AF are supposed to contribute to development, progression and self-perpetuation of AF. SCOPE OF REVIEW The present review summarizes the sources and targets of ROS/RNS in the setting of AF and focuses on key redox-sensitive signaling pathways that are implicated in the pathogenesis of AF and function either to aggravate or protect from disease. MAJOR CONCLUSIONS NADPH oxidases and various mitochondrial monooxygenases are major sources of ROS during AF. Besides direct oxidative modification of e.g. ion channels and ion handling proteins that are crucially involved in action potential generation and duration, AF leads to the reversible activation of redox-sensitive signaling pathways mediated by activation of redox-regulated proteins including Nrf2, NF-κB, and CaMKII. Both processes are recognized to contribute to the formation of a substrate for AF and, thus, to increase AF inducibility and duration. GENERAL SIGNIFICANCE AF is a prevalent disease and due to the current demographic developments its socio-economic relevance will further increase. Improving our understanding of the role that ROS and redox-related (patho)-mechanisms play in the development and progression of AF may allow the development of a targeted therapy for AF that surpasses the efficacy of previous general anti-oxidative strategies. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.
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Affiliation(s)
- Carmen Wolke
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany
| | - Alicja Bukowska
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany
| | - Andreas Goette
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany; Department of Cardiology and Intensive Care Medicine, St. Vincenz-Hospital, D-33098 Paderborn, Germany
| | - Uwe Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany.
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31
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Mamchur S, Mamchur I, Khomenko E, Kokov A, Bokhan N, Sherbinina D. Mechanical function of left atrium and pulmonary vein sleeves before and after their antrum isolation. MEDICINA-LITHUANIA 2014; 50:353-9. [PMID: 25541269 DOI: 10.1016/j.medici.2014.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND AND OBJECTIVE Pulmonary vein (PV) sleeves are established as the main substrate taking part in the mechanisms of atrial fibrillation (AF) initiation. However, we have extremely few data concerning their physiological role in the heart contractility. The aim of the study was to estimate the mechanical function of the left atrium (LA) and PV sleeves before and early after their isolation. MATERIALS AND METHODS A total of 17 patients with a mean age of 57.4±8.3 years who underwent PVs isolation due to AF were enrolled in the study. A day before the procedure a computed tomography (CT) of the LA and PVs and dopplerography of transmitral flow were performed. During the procedure the mechanical function of the LA and PV sleeves were estimated by transesophageal echocardiography and manometry in the left heart chambers. RESULTS During the invasive study the patterns of the heart chambers and PV sleeves pressure were identified. These patterns confirmed the active role of the PV sleeves in LA filling and active LA relaxation during left ventricular systole. After PV isolation an alteration of transmitral blood flow and increase of LA pressure were registered. However, diastolic dysfunction was ruled out by LV manometry, thereby testifying LA mechanical function disturbance. The change in PV hemodynamics also occurred as a result of the decrease in PV sleeves contractility, revealed by manometry and paired CT scans. CONCLUSIONS The PVs take an active part in left atrial filling by contraction of their sleeves. Antrum isolation of the PVs leads to the deterioration of their contractility and LA reservoir function.
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Affiliation(s)
- Sergey Mamchur
- Department of Arrhythmology and Pacing, Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, Russian Federation.
| | - Irina Mamchur
- Department of Arrhythmology and Pacing, Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, Russian Federation
| | - Egor Khomenko
- Department of Arrhythmology and Pacing, Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, Russian Federation
| | - Alexander Kokov
- Department of Arrhythmology and Pacing, Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, Russian Federation
| | - Nikita Bokhan
- Department of Arrhythmology and Pacing, Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, Russian Federation
| | - Diana Sherbinina
- Department of Arrhythmology and Pacing, Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, Russian Federation
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32
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Duration of electrically induced atrial fibrillation is augmented by high voltage of stimulus with higher blood pressure in hypertensive rats. Int J Hypertens 2014; 2014:980505. [PMID: 25328683 PMCID: PMC4195393 DOI: 10.1155/2014/980505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 09/15/2014] [Indexed: 11/29/2022] Open
Abstract
Objective. Many previous clinical studies have suggested that atrial fibrillation (AF) is closely associated with hypertension. However, the benefits of antihypertensive therapy on AF are still inconsistent, and it is necessary to explore the factors augmenting AF in hypertensive rats. The aim of the present study was to investigate the correlation between arterial pressure or voltage stimulus and to the duration of electrically induced AF in normotensive or hypertensive rats. Methods. AF was reproducibly induced by transesophageal atrial burst pacing in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). We did the burst pacing at high (20 V) or low (5 V) voltage. Results. Duration of AF did not correlate with systolic blood pressure (SBP) and stimulus voltage in WKY. However, only in SHR, duration of AF with high stimulus voltage significantly correlated with SBP and was significantly longer in high than in low voltage stimulus. Discussion and Conclusion. Duration of AF is augmented by high voltage stimulus with higher blood pressure in SHR.
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Factors Associated with Proximal Carotid Axis Occlusion in Patients with Acute Stroke and Atrial Fibrillation. J Stroke Cerebrovasc Dis 2014; 23:799-804. [DOI: 10.1016/j.jstrokecerebrovasdis.2013.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 06/30/2013] [Accepted: 07/05/2013] [Indexed: 11/20/2022] Open
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Bukowska A, Lendeckel U, Goette A. Atrial Calpains: Mediators of Atrialmyopathies in Atrial Fibrillation. J Atr Fibrillation 2014; 6:1021. [PMID: 27957058 DOI: 10.4022/jafib.1021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 02/21/2014] [Accepted: 03/04/2014] [Indexed: 01/24/2023]
Abstract
Atrial fibrillation (AF) is associated with substantial structural changes at cell and tissue level. Cellular hypertrophy, disintegration of sarcomeres, mitochondrial swelling and apoptosis have been described as typical histo-morphologic alterations in AF. Main initiators for cellular alterations in fibrillating atrial myocytes are cytosolic calcium overload and oxidative stress. Calpains are intracellular Ca2+- activated proteases and important mediators of calcium overload. Activation of calpains and down-regulation of the calpain inhibitor, calpastatin, contribute to myocardial damage in fibrillating atria. Thus, deregulations of the expression, activity, or subcellular localization of calpain within atrial myocytes have been established as important mediators of atrial myopathy during AF.
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Affiliation(s)
- Alicja Bukowska
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, Germany
| | - Uwe Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, Ernst-Moritz-Arndt University,Greifswald, Germany
| | - Andreas Goette
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, Germany; Department of Cardiology and Intensive Care Medicine, St. Vincenz-Hospital, Paderborn,Germany
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Gupta S, Figueredo VM. Tachycardia mediated cardiomyopathy: Pathophysiology, mechanisms, clinical features and management. Int J Cardiol 2014; 172:40-6. [DOI: 10.1016/j.ijcard.2013.12.180] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 12/23/2013] [Accepted: 12/30/2013] [Indexed: 11/25/2022]
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Johnsen AB, Høydal M, Røsbjørgen R, Stølen T, Wisløff U. Aerobic interval training partly reverse contractile dysfunction and impaired Ca2+ handling in atrial myocytes from rats with post infarction heart failure. PLoS One 2013; 8:e66288. [PMID: 23799089 PMCID: PMC3682943 DOI: 10.1371/journal.pone.0066288] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 05/05/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND There is limited knowledge about atrial myocyte Ca(2+) handling in the failing hearts. The aim of this study was to examine atrial myocyte contractile function and Ca(2+) handling in rats with post-infarction heart failure (HF) and to examine whether aerobic interval training could reverse a potential dysfunction. METHODS AND RESULTS Post-infarction HF was induced in Sprague Dawley rats by ligation of the left descending coronary artery. Atrial myocyte shortening was depressed (p<0.01) and time to relaxation was prolonged (p<0.01) in sedentary HF-rats compared to healthy controls. This was associated with decreased Ca(2+) amplitude, decreased SR Ca(2+) content, and slower Ca(2+) transient decay. Atrial myocytes from HF-rats had reduced sarcoplasmic reticulum Ca(2+) ATPase activity, increased Na(+)/Ca(2+)-exchanger activity and increased diastolic Ca(2+) leak through ryanodine receptors. High intensity aerobic interval training in HF-rats restored atrial myocyte contractile function and reversed changes in atrial Ca(2+) handling in HF. CONCLUSION Post infarction HF in rats causes profound impairment in atrial myocyte contractile function and Ca(2+) handling. The observed dysfunction in atrial myocytes was partly reversed after aerobic interval training.
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Affiliation(s)
- Anne Berit Johnsen
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Morten Høydal
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ragnhild Røsbjørgen
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tomas Stølen
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ulrik Wisløff
- K.G. Jebsen Center of Exercise in Medicine, Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
- * E-mail:
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Colman MA, Aslanidi OV, Kharche S, Boyett MR, Garratt C, Hancox JC, Zhang H. Pro-arrhythmogenic effects of atrial fibrillation-induced electrical remodelling: insights from the three-dimensional virtual human atria. J Physiol 2013; 591:4249-72. [PMID: 23732649 PMCID: PMC3779115 DOI: 10.1113/jphysiol.2013.254987] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Chronic atrial fibrillation (AF) is associated with structural and electrical remodelling in the atria, which are associated with a high recurrence of AF. Through biophysically detailed computer modelling, this study investigated mechanisms by which AF-induced electrical remodelling promotes and perpetuates AF. A family of Courtemanche–Ramirez–Nattel variant models of human atrial cell action potentials (APs), taking into account of intrinsic atrial electrophysiological properties, was modified to incorporate various experimental data sets on AF-induced changes of major ionic channel currents (ICaL, IKur, Ito, IK1, IKs, INaCa) and on intracellular Ca2+ handling. The single cell models for control and AF-remodelled conditions were incorporated into multicellular three-dimensional (3D) atrial tissue models. Effects of the AF-induced electrical remodelling were quantified as the changes of AP profile, AP duration (APD) and its dispersion across the atria, and the vulnerability of atrial tissue to the initiation of re-entry. The dynamic behaviour of re-entrant excitation waves in the 3D models was characterised. In our simulations, AF-induced electrical remodelling abbreviated atrial APD non-uniformly across the atria; this resulted in relatively short APDs co-existing with marked regional differences in the APD at junctions of the crista terminalis/pectinate muscle, pulmonary veins/left atrium. As a result, the measured tissue vulnerability to re-entry initiation at these tissue junctions was increased. The AF-induced electrical remodelling also stabilized and accelerated re-entrant excitation waves, leading to rapid and sustained re-entry. Under the AF-remodelled condition, re-entrant scroll waves in the 3D model degenerated into persistent and erratic wavelets, leading to fibrillation. In conclusion, realistic 3D atrial tissue models indicate that AF-induced electrical remodelling produces regionally heterogeneous and shortened APD; these respectively facilitate initiation and maintenance of re-entrant excitation waves.
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Affiliation(s)
- Michael A Colman
- Professor H. Zhang: School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK.
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38
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Greiser M, Schotten U. Dynamic remodeling of intracellular Ca2+ signaling during atrial fibrillation. J Mol Cell Cardiol 2013; 58:134-42. [DOI: 10.1016/j.yjmcc.2012.12.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/14/2012] [Accepted: 12/17/2012] [Indexed: 12/23/2022]
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Marx SO, Marks AR. Dysfunctional ryanodine receptors in the heart: new insights into complex cardiovascular diseases. J Mol Cell Cardiol 2013; 58:225-31. [PMID: 23507255 DOI: 10.1016/j.yjmcc.2013.03.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/26/2013] [Accepted: 03/02/2013] [Indexed: 01/07/2023]
Abstract
Calcium dependent signaling is highly regulated in cardiomyocytes and determines the force of cardiac muscle contraction. The cardiac ryanodine receptors (RyR2) play important roles in health and disease. Modulation of RyR2 by phosphorylation is required for sympathetic regulation of cardiac function. Abnormal regulation of RyR2 contributes to heart failure, and atrial and ventricular arrhythmias. RyR2 channels are oxidized, nitrosylated, and hyperphosphorylated by protein kinase A (PKA) in heart failure, resulting in "leaky" channels. These leaky RyR2 channels contribute to depletion of calcium from the sarcoplasmic reticulum, resulting in defective cardiac excitation-contraction coupling. In this review, we discuss both the importance of PKA and calcium/calmodulin-dependent kinase II (CaMKII) regulation of RyR2 in health, and how altered phosphorylation, nitrosylation and oxidation of RyR2 channels lead to cardiac disease. Correcting these defects using either genetic manipulation (knock-in) in mice, or specific and novel small molecules ameliorates the RyR2 dysfunction, reducing the progression to heart failure and the incidence of arrhythmias.
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Affiliation(s)
- Steven O Marx
- Division of Cardiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
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40
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Atrial remodeling: New pathophysiological mechanism of atrial fibrillation. Med Hypotheses 2013; 80:53-6. [DOI: 10.1016/j.mehy.2012.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 10/18/2012] [Indexed: 11/17/2022]
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41
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Lakkireddy D, Di Biase L, Ryschon K, Biria M, Swarup V, Reddy YM, Verma A, Bommana S, Burkhardt D, Dendi R, Dello Russo A, Casella M, Carbucicchio C, Tondo C, Dawn B, Natale A. Radiofrequency Ablation of Premature Ventricular Ectopy Improves the Efficacy of Cardiac Resynchronization Therapy in Nonresponders. J Am Coll Cardiol 2012; 60:1531-9. [DOI: 10.1016/j.jacc.2012.06.035] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 06/13/2012] [Accepted: 06/26/2012] [Indexed: 10/27/2022]
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Xie LH, Shanmugam M, Park JY, Zhao Z, Wen H, Tian B, Periasamy M, Babu GJ. Ablation of sarcolipin results in atrial remodeling. Am J Physiol Cell Physiol 2012; 302:C1762-71. [PMID: 22496245 DOI: 10.1152/ajpcell.00425.2011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Sarcolipin (SLN) is a key regulator of sarco(endo)plasmic reticulum (SR) Ca(2+)-ATPase (SERCA), and its expression is altered in diseased atrial myocardium. To determine the precise role of SLN in atrial Ca(2+) homeostasis, we developed a SLN knockout (sln-/-) mouse model and demonstrated that ablation of SLN enhances atrial SERCA pump activity. The present study is designed to determine the long-term effects of enhanced SERCA activity on atrial remodeling in the sln-/- mice. Calcium transient measurements show an increase in atrial SR Ca(2+) load and twitch Ca(2+) transients. Patch-clamping experiments demonstrate activation of the forward mode of sodium/calcium exchanger, increased L-type Ca(2+) channel activity, and prolongation of action potential duration at 90% repolarization in the atrial myocytes of sln-/- mice. Spontaneous Ca(2+) waves, delayed afterdepolarization, and triggered activities are frequent in the atrial myocytes of sln-/- mice. Furthermore, loss of SLN in atria is associated with increased interstitial fibrosis and altered expression of genes encoding collagen and other extracellular matrix proteins. Our results also show that the sln-/- mice are susceptible to atrial arrhythmias upon aging. Together, these findings indicate that ablation of SLN results in increased SERCA activity and SR Ca(2+) load, which, in turn, could cause abnormal intracellular Ca(2+) handling and atrial remodeling.
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Affiliation(s)
- Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, 07103, USA
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Collins TP, Terrar DA. Ca(2+)-stimulated adenylyl cyclases regulate the L-type Ca(2+) current in guinea-pig atrial myocytes. J Physiol 2012; 590:1881-93. [PMID: 22351635 DOI: 10.1113/jphysiol.2011.227066] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Ca(2+)-stimulated adenylyl cyclases (ACs) have recently been shown to play important roles in pacemaking in the sino-atrial node. Here we present evidence that Ca(2+)-stimulated ACs are functionally active in guinea-pig atrial myocytes. Basal activity of an AC in isolated atrial myocytes was demonstrated by the observations that MDL 12,330A (10 μm), an AC inhibitor, reduced L-type Ca(2+) current (I(CaL)) amplitude, while inhibition of phosphodiesterases with IBMX (100 μm) increased I(CaL) amplitude. Buffering of cytosolic Ca(2+) by exposure of myocytes to BAPTA-AM (5 μm) reduced I(CaL) amplitude, as did inhibition of Ca(2+) release from the sarcoplasmic reticulum with ryanodine (2 μm) and thapsigargin (1 μm). [Ca(2+)]i-activated calmodulin kinase II (CaMKII) inhibition with KN-93 (1 μm) reduced I(CaL), but subsequent application of BAPTA-AM further reduced I(CaL). This effect of BAPTA-AM, in the presence of CaMKII inhibition, demonstrates that there is an additional Ca(2+)-modulated pathway (not dependent on CaMKII) that regulates I(CaL) in atrial myocytes. The effects of BAPTA could be reversed by forskolin (10 μm), a direct stimulator of all AC isoforms, which would restore cAMP levels. In the presence of BAPTA-AM, the actions of IBMX were reduced. In addition, inclusion of cAMP in the patch electrode in the whole-cell configuration prevented the effects of BAPTA. These effects are all consistent with a role for Ca(2+)-stimulated AC in the regulation of atrial myocyte I(CaL).
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Affiliation(s)
- Thomas P Collins
- National Heart and Lung Institute, Imperial College, Guy Scadding Building, Dovehouse Street, London SW3 6LY, UK.
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Kalogeropoulos AS, Tsiodras S, Rigopoulos AG, Sakadakis EA, Triantafyllis A, Kremastinos DTH, Rizos I. Novel association patterns of cardiac remodeling markers in patients with essential hypertension and atrial fibrillation. BMC Cardiovasc Disord 2011; 11:77. [PMID: 22204652 PMCID: PMC3276440 DOI: 10.1186/1471-2261-11-77] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 12/28/2011] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are essential for the cardiac extracellular matrix (ECM) remodeling. We investigated differences in serum levels of these markers between patients with atrial fibrillation (AF) and sinus rhythm (SR). METHODS Serum levels of MMP-2, MMP-3, MMP-9 and TIMP-1 were measured in 86 patients: 27 on SR without any AF history, 33 with paroxysmal and 26 with permanent AF. All subjects had essential hypertension, normal systolic function and no coronary artery disease. RESULTS Patients with AF had higher MMP-2, MMP-3 and MMP-9 and lower TIMP-1 compared to SR subjects (all p < 0.001). Paroxysmal AF was associated with higher MMP-2 levels compared to permanent AF (p < 0.001). Matrix metalloproteinase-9 but not MMP-3 was higher in permanent compared to paroxysmal AF group (p < 0.001). Patients with AF had lower levels of TIMP-1 compared to those with SR while permanent AF subjects had lower TIMP-1 levels than those with paroxysmal AF (p < 0.001 for both comparisons). Lower TIMP-1 was the only independent factor associated with AF (OR: 0.259, 95%CI: 0.104-0.645, p = 0.004). CONCLUSIONS In hypertensives, paroxysmal AF and permanent AF differ with respect to serum MMPs. Increased MMP-2 is associated with paroxysmal, whereas increased MMP-9 with permanent AF. Additionally, lower levels of TIMP-1 had a strong association with AF incidence.
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Affiliation(s)
- Andreas S Kalogeropoulos
- Department of Cardiology, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Sotirios Tsiodras
- 4th Academic Department of Internal Medicine and Infectious Diseases, University of Athens Medical School, Attikon University Hospital, Athens, Greece
| | - Angelos G Rigopoulos
- 2nd Department of Cardiology, University of Athens Medical School, Attikon University Hospital, Athens, Greece
| | - Eleftherios A Sakadakis
- 2nd Department of Cardiology, University of Athens Medical School, Attikon University Hospital, Athens, Greece
| | - Andreas Triantafyllis
- 2nd Department of Cardiology, University of Athens Medical School, Attikon University Hospital, Athens, Greece
| | - Dimitrios TH Kremastinos
- 2nd Department of Cardiology, University of Athens Medical School, Attikon University Hospital, Athens, Greece
| | - Ioannis Rizos
- 2nd Department of Cardiology, University of Athens Medical School, Attikon University Hospital, Athens, Greece
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Sharma D, Li G, Xu G, Liu Y, Xu Y. Atrial remodeling in atrial fibrillation and some related microRNAs. Cardiology 2011; 120:111-21. [PMID: 22179059 DOI: 10.1159/000334434] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 10/12/2011] [Indexed: 01/17/2023]
Abstract
Atrial fibrillation is the most common sustained arrhythmia associated with substantial cardiovascular morbidity and mortality, with stroke being the most critical complication. The role of atrial remodeling has emerged as the new pathophysiological mechanism of atrial fibrillation. Electrical remodeling and structural remodeling will increase the probability of generating multiple atrial wavelets by enabling rapid atrial activation and dispersion of refractoriness. MicroRNAs (miRNAs) are small non-coding RNAs of 20-25 nucleotides in length that regulate expression of target genes through sequence-specific hybridization to the 3' untranslated region of messenger RNAs and either block translation or direct degradation of their target messenger RNA. They have also been implicated in a variety of pathological conditions, such as arrhythmogenesis and atrial fibrillation. Target genes of miRNAs have the potential to affect atrial fibrillation vulnerability.
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Affiliation(s)
- Deepak Sharma
- International College of Tianjin Medical University, Tianjin, China
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Decreased sarcolipin protein expression and enhanced sarco(endo)plasmic reticulum Ca2+ uptake in human atrial fibrillation. Biochem Biophys Res Commun 2011; 410:97-101. [PMID: 21640081 DOI: 10.1016/j.bbrc.2011.05.113] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 05/19/2011] [Indexed: 11/24/2022]
Abstract
Sarcolipin (SLN), a key regulator of cardiac sarco(endo)plasmic reticulum (SR) Ca(2+) ATPase, is predominantly expressed in atria and mediates β-adrenergic responses. Studies have shown that SLN mRNA expression is decreased in human chronic atrial fibrillation (AF) and in aortic banded mouse atria; however, SLN protein expression in human atrial pathology and its role in atrial SR Ca(2+) uptake are not yet elucidated. In the present study, we determined the expression of major SR Ca(2+) handling proteins in atria of human AF patients and in human and in a mouse model of heart failure (HF). We found that the expression of SR Ca(2+) uptake and Ca(2+) release channel proteins are significantly decreased in atria but not in the ventricles of pressure-overload induced HF in mice. In human AF and HF, the expression of SLN protein was significantly decreased; whereas the expressions of other major SR Ca(2+) handling proteins were not altered. Further, we found that the SR Ca(2+) uptake was significantly increased in human AF. The selective downregulation of SLN and enhanced SR Ca(2+) uptake in human AF suggest that SLN downregulation could play an important role in abnormal intracellular Ca(2+) cycling in atrial pathology.
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47
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Greiser M, Lederer WJ, Schotten U. Alterations of atrial Ca(2+) handling as cause and consequence of atrial fibrillation. Cardiovasc Res 2010; 89:722-33. [PMID: 21159669 DOI: 10.1093/cvr/cvq389] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Atrial fibrillation (AF) is the most prevalent sustained arrhythmia. As the most important risk factor for embolic stroke, AF is associated with a high morbidity and mortality. Despite decades of research, successful (pharmacological and interventional) 'ablation' of the arrhythmia remains challenging. AF is characterized by a diverse aetiology, including heart failure, hypertension, and valvular disease. Based on this understanding, new treatment strategies that are specifically tailored to the underlying pathophysiology of a certain 'type' of AF are being developed. One important aspect of AF pathophysiology is altered intracellular Ca(2+) handling. Due to the increase in the atrial activation rate and the subsequent initial [Ca(2+)](i) overload, AF induces 'remodelling' of intracellular Ca(2+) handling. Current research focuses on unravelling the contribution of altered intracellular Ca(2+) handling to different types of AF. More specifically, changes in intracellular Ca(2+) homeostasis preceding the onset of AF, in conditions which predispose to AF (e.g. heart failure), appear to be different from changes in Ca(2+) handling developing after the onset of AF. Here we review and critique altered intracellular Ca(2+) handling and its contribution to three specific aspects of AF pathophysiology, (i) excitation-transcription coupling and Ca(2+)-dependent signalling pathways, (ii) atrial contractile dysfunction, and (iii) arrhythmogenicity.
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Affiliation(s)
- Maura Greiser
- Department of Physiology, Maastricht University, Maastricht, The Netherlands
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48
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Bukowska A, Lendeckel U, Bode-Böger SM, Goette A. Physiologic and Pathophysiologic Role of Calpain: Implications for the Occurrence of Atrial Fibrillation. Cardiovasc Ther 2010; 30:e115-27. [DOI: 10.1111/j.1755-5922.2010.00245.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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49
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Kushnir A, Marks AR. The ryanodine receptor in cardiac physiology and disease. ADVANCES IN PHARMACOLOGY 2010; 59:1-30. [PMID: 20933197 DOI: 10.1016/s1054-3589(10)59001-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
According to the American Heart Association it is estimated that the United States will spend close to $39 billion in 2010 to treat over five million Americans suffering from heart failure. Patients with heart failure suffer from dyspnea and decreased exercised tolerance and are at increased risk for fatal ventricular arrhythmias. Food and Drug Administration -approved pharmacologic therapies for heart failure include diuretics, inhibitors of the renin-angiotensin system, and β-adrenergic receptor antagonists. Over the past 20 years advances in the field of ryanodine receptor (RyR2)/calcium release channel research have greatly advanced our understanding of cardiac physiology and the pathogenesis of heart failure and arrhythmias. Here we review the key observations, controversies, and discoveries that have led to the development of novel compounds targeting the RyR2/calcium release channel for treating heart failure and for preventing lethal arrhythmias.
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Affiliation(s)
- Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, College of Physicians and Surgeons of Columbia University, New York, NY, USA
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50
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Dobrev D, Voigt N, Wehrens XHT. The ryanodine receptor channel as a molecular motif in atrial fibrillation: pathophysiological and therapeutic implications. Cardiovasc Res 2010; 89:734-43. [PMID: 20943673 DOI: 10.1093/cvr/cvq324] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with substantial morbidity and mortality. It causes profound changes in sarcoplasmic reticulum (SR) Ca(2+) homeostasis, including ryanodine receptor channel dysfunction and diastolic SR Ca(2+) leak, which might contribute to both decreased contractile function and increased propensity to atrial arrhythmias. In this review, we will focus on the molecular basis of ryanodine receptor channel dysfunction and enhanced diastolic SR Ca(2+) leak in AF. The potential relevance of increased incidence of spontaneous SR Ca(2+) release for both AF induction and/or maintenance and the development of novel mechanism-based therapeutic approaches will be discussed.
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Affiliation(s)
- Dobromir Dobrev
- Division of Experimental Cardiology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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