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Gong Y, Kong B, Shuai W, Chen T, Zhang JJ, Huang H. USP38 regulates inflammatory cardiac remodeling after myocardial infarction. Clin Sci (Lond) 2023; 137:1665-1681. [PMID: 37903290 DOI: 10.1042/cs20230728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/01/2023]
Abstract
BACKGROUND The inflammatory response and subsequent ventricular remodeling are key factors contributing to ventricular arrhythmias (VAs) after myocardial infarction (MI). Ubiquitin-specific protease 38 (USP38) is a member of the USP family, but the impact of USP38 in arrhythmia substrate generation after MI remains unclear. This study aimed to determine the role of USP38 in post-MI VAs and its underlying mechanisms. METHODS AND RESULTS Surgical left descending coronary artery ligation was used to construct MI models. Morphological, biochemical, histological, and electrophysiological studies and molecular analyses were performed after MI on days 3 and 28. We found that the USP38 expression was remarkably increased after MI. Cardiac-conditional USP38 knockout (USP38-CKO) reduces the expression of the inflammatory marker CD68 as well as the inflammatory factors TNF-α and IL-1β after MI, thereby alleviating advanced cardiac fibrosis, electrical remodeling, ion channel remodeling, and susceptibility to VAs. In contrast, cardiac-specific USP38 overexpression (USP38-TG) showed a significant opposite effect, exacerbating the early inflammatory response and cardiac remodeling after MI. Mechanistically, USP38 knockout inhibited activation of the TAK1/NF-κB signaling pathway after MI, whereas USP38 overexpression enhanced activation of the TAK1/NF-κB signaling pathway after MI. CONCLUSIONS Our study confirms that USP38-CKO attenuates the inflammatory response, improves ventricular remodeling after myocardial infarction, and reduces susceptibility to malignant VA by inhibiting the activation of the TAK1/NF-κB pathway, with USP38-TG playing an opposing role. These results suggest that USP38 may be an important target for the treatment of cardiac remodeling and arrhythmias after MI.
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Affiliation(s)
- Yang Gong
- Department of Cardiology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei 430060, China
- Cardiovascular Research Institute of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Bin Kong
- Department of Cardiology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei 430060, China
- Cardiovascular Research Institute of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Wei Shuai
- Department of Cardiology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei 430060, China
- Cardiovascular Research Institute of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Tao Chen
- Department of Cardiology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei 430060, China
- Cardiovascular Research Institute of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Jing Jing Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei 430060, China
- Cardiovascular Research Institute of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, China
| | - He Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, Hubei 430060, China
- Cardiovascular Research Institute of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, China
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Chakraborty P, Azam MA, Massé S, Lai PF, Rose RA, Ibarra Moreno CA, Riazi S, Nanthakumar K. Uncoupling cytosolic calcium from membrane voltage by transient receptor potential melastatin 4 channel (TRPM4) modulation: A novel strategy to treat ventricular arrhythmias. Heart Rhythm O2 2023; 4:725-732. [PMID: 38034891 PMCID: PMC10685170 DOI: 10.1016/j.hroo.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023] Open
Abstract
The current antiarrhythmic paradigm is mainly centered around modulating membrane voltage. However, abnormal cytosolic calcium (Ca2+) signaling, which plays an important role in driving membrane voltage, has not been targeted for therapeutic purposes in arrhythmogenesis. There is clear evidence for bidirectional coupling between membrane voltage and intracellular Ca2+. Cytosolic Ca2+ regulates membrane voltage through Ca2+-sensitive membrane currents. As a component of Ca2+-sensitive currents, Ca2+-activated nonspecific cationic current through the TRPM4 (transient receptor potential melastatin 4) channel plays a significant role in Ca2+-driven changes in membrane electrophysiology. In myopathic and ischemic ventricles, upregulation and/or enhanced activity of this current is associated with the generation of afterdepolarization (both early and delayed), reduction of repolarization reserve, and increased propensity to ventricular arrhythmias. In this review, we describe a novel concept for the management of ventricular arrhythmias in the remodeled ventricle based on mechanistic concepts from experimental studies, by uncoupling the Ca2+-induced changes in membrane voltage by inhibition of this TRPM4-mediated current.
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Affiliation(s)
- Praloy Chakraborty
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Mohammed Ali Azam
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Stéphane Massé
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Patrick F.H. Lai
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Robert A. Rose
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Carlos A. Ibarra Moreno
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology and Pain Medicine, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Sheila Riazi
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology and Pain Medicine, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Kumaraswamy Nanthakumar
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
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3
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Grandi E, Navedo MF, Saucerman JJ, Bers DM, Chiamvimonvat N, Dixon RE, Dobrev D, Gomez AM, Harraz OF, Hegyi B, Jones DK, Krogh-Madsen T, Murfee WL, Nystoriak MA, Posnack NG, Ripplinger CM, Veeraraghavan R, Weinberg S. Diversity of cells and signals in the cardiovascular system. J Physiol 2023; 601:2547-2592. [PMID: 36744541 PMCID: PMC10313794 DOI: 10.1113/jp284011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/19/2023] [Indexed: 02/07/2023] Open
Abstract
This white paper is the outcome of the seventh UC Davis Cardiovascular Research Symposium on Systems Approach to Understanding Cardiovascular Disease and Arrhythmia. This biannual meeting aims to bring together leading experts in subfields of cardiovascular biomedicine to focus on topics of importance to the field. The theme of the 2022 Symposium was 'Cell Diversity in the Cardiovascular System, cell-autonomous and cell-cell signalling'. Experts in the field contributed their experimental and mathematical modelling perspectives and discussed emerging questions, controversies, and challenges in examining cell and signal diversity, co-ordination and interrelationships involved in cardiovascular function. This paper originates from the topics of formal presentations and informal discussions from the Symposium, which aimed to develop a holistic view of how the multiple cell types in the cardiovascular system integrate to influence cardiovascular function, disease progression and therapeutic strategies. The first section describes the major cell types (e.g. cardiomyocytes, vascular smooth muscle and endothelial cells, fibroblasts, neurons, immune cells, etc.) and the signals involved in cardiovascular function. The second section emphasizes the complexity at the subcellular, cellular and system levels in the context of cardiovascular development, ageing and disease. Finally, the third section surveys the technological innovations that allow the interrogation of this diversity and advancing our understanding of the integrated cardiovascular function and dysfunction.
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Affiliation(s)
- Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Manuel F. Navedo
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Jeffrey J. Saucerman
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Nipavan Chiamvimonvat
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- Department of Internal Medicine, University of California Davis, Davis, CA, USA
| | - Rose E. Dixon
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montréal, Canada
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Ana M. Gomez
- Signaling and Cardiovascular Pathophysiology-UMR-S 1180, INSERM, Université Paris-Saclay, Orsay, France
| | - Osama F. Harraz
- Department of Pharmacology, Larner College of Medicine, and Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, VT, USA
| | - Bence Hegyi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - David K. Jones
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Trine Krogh-Madsen
- Department of Physiology & Biophysics, Weill Cornell Medicine, New York, New York, USA
| | - Walter Lee Murfee
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Matthew A. Nystoriak
- Department of Medicine, Division of Environmental Medicine, Center for Cardiometabolic Science, University of Louisville, Louisville, KY, 40202, USA
| | - Nikki G. Posnack
- Department of Pediatrics, Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
- Sheikh Zayed Institute for Pediatric and Surgical Innovation, Children’s National Heart Institute, Children’s National Hospital, Washington, DC, USA
| | | | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
- Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University – Wexner Medical Center, Columbus, OH, USA
| | - Seth Weinberg
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
- Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University – Wexner Medical Center, Columbus, OH, USA
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Liu T, Li T, Xu D, Wang Y, Zhou Y, Wan J, Huang CLH, Tan X. Small-conductance calcium-activated potassium channels in the heart: expression, regulation and pathological implications. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220171. [PMID: 37122223 PMCID: PMC10150224 DOI: 10.1098/rstb.2022.0171] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/25/2022] [Indexed: 05/02/2023] Open
Abstract
Ca2+-activated K+ channels are critical to cellular Ca2+ homeostasis and excitability; they couple intracellular Ca2+ and membrane voltage change. Of these, the small, 4-14 pS, conductance SK channels include three, KCNN1-3 encoded, SK1/KCa2.1, SK2/KCa2.2 and SK3/KCa2.3, channel subtypes with characteristic, EC50 ∼ 10 nM, 40 pM, 1 nM, apamin sensitivities. All SK channels, particularly SK2 channels, are expressed in atrial, ventricular and conducting system cardiomyocytes. Pharmacological and genetic modification results have suggested that SK channel block or knockout prolonged action potential durations (APDs) and effective refractory periods (ERPs) particularly in atrial, but also in ventricular, and sinoatrial, atrioventricular node and Purkinje myocytes, correspondingly affect arrhythmic tendency. Additionally, mitochondrial SK channels may decrease mitochondrial Ca2+ overload and reactive oxygen species generation. SK channels show low voltage but marked Ca2+ dependences (EC50 ∼ 300-500 nM) reflecting their α-subunit calmodulin (CaM) binding domains, through which they may be activated by voltage-gated or ryanodine-receptor Ca2+ channel activity. SK function also depends upon complex trafficking and expression processes and associations with other ion channels or subunits from different SK subtypes. Atrial and ventricular clinical arrhythmogenesis may follow both increased or decreased SK expression through decreased or increased APD correspondingly accelerating and stabilizing re-entrant rotors or increasing incidences of triggered activity. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- Ting Liu
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Tao Li
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Cardiology, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Dandi Xu
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Yan Wang
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Yafei Zhou
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Juyi Wan
- Department of Cardiovascular Surgery, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Christopher L.-H. Huang
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Physiological Laboratory and Department of Biochemistry, University of Cambridge, Cambridge CB2 3EG, UK
| | - Xiaoqiu Tan
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Cardiology, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Physiology, School of Basic Medical Sciences, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
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Xia R, Tomsits P, Loy S, Zhang Z, Pauly V, Schüttler D, Clauss S. Cardiac Macrophages and Their Effects on Arrhythmogenesis. Front Physiol 2022; 13:900094. [PMID: 35812333 PMCID: PMC9257039 DOI: 10.3389/fphys.2022.900094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 05/30/2022] [Indexed: 12/24/2022] Open
Abstract
Cardiac electrophysiology is a complex system established by a plethora of inward and outward ion currents in cardiomyocytes generating and conducting electrical signals in the heart. However, not only cardiomyocytes but also other cell types can modulate the heart rhythm. Recently, cardiac macrophages were demonstrated as important players in both electrophysiology and arrhythmogenesis. Cardiac macrophages are a heterogeneous group of immune cells including resident macrophages derived from embryonic and fetal precursors and recruited macrophages derived from circulating monocytes from the bone marrow. Recent studies suggest antiarrhythmic as well as proarrhythmic effects of cardiac macrophages. The proposed mechanisms of how cardiac macrophages affect electrophysiology vary and include both direct and indirect interactions with other cardiac cells. In this review, we provide an overview of the different subsets of macrophages in the heart and their possible interactions with cardiomyocytes under both physiologic conditions and heart disease. Furthermore, we elucidate similarities and differences between human, murine and porcine cardiac macrophages, thus providing detailed information for researchers investigating cardiac macrophages in important animal species for electrophysiologic research. Finally, we discuss the pros and cons of mice and pigs to investigate the role of cardiac macrophages in arrhythmogenesis from a translational perspective.
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Affiliation(s)
- Ruibing Xia
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Philipp Tomsits
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Simone Loy
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Zhihao Zhang
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Valerie Pauly
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Dominik Schüttler
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Sebastian Clauss
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
- *Correspondence: Sebastian Clauss,
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Chang JH, Cheng CC, Lu YY, Chung CC, Yeh YH, Chen YC, Higa S, Chen SA, Chen YJ. Vascular endothelial growth factor modulates pulmonary vein arrhythmogenesis via vascular endothelial growth factor receptor 1/NOS pathway. Eur J Pharmacol 2021; 911:174547. [PMID: 34624234 DOI: 10.1016/j.ejphar.2021.174547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/22/2021] [Accepted: 09/29/2021] [Indexed: 11/26/2022]
Abstract
Atrial fibrillation (AF) is a common form of arrhythmia with serious public health impacts, but its underlying mechanisms are not yet fully understood. Vascular endothelial growth factor (VEGF) is highly expressed in the atrium of patients with AF, but whether VEGF affects AF pathogenesis remains unclear. Pulmonary veins (PVs) are important sources for the genesis of atrial tachycardia or AF. Therefore, this study assessed the effects of VEGF on PV electrophysiological properties and evaluated its underlying mechanisms. Conventional microelectrodes and whole-cell patch clamps were performed using isolated rabbit PV preparations or single isolated PV cardiomyocytes before and after VEGF or VEGF receptor (VEGFR), Akt, NOS inhibitor administration. We found that VEGF (0.1, 1, and 10 ng/mL) reduced the PV beating rate in a dose-dependent manner. Furthermore, VEGF (10 ng/mL) reduced late diastolic depolarization and diastolic tension. Isoproterenol increased PV beating and burst firing, which was attenuated by VEGF (1 ng/mL). In the presence of VEGFR-1 inhibition (ZM306416 at 10 μM) and L-NAME (100 μM), VEGF (1 ng/mL) did not alter PV spontaneous activity. In isolated PV cardiomyocytes, VEGF (1 ng/mL) decreased L-type calcium, sodium/calcium exchanger, and late sodium currents. In conclusion, we found that VEGF reduces PV arrhythmogenesis by modulating sodium/calcium homeostasis through VEGFR-1/NOS signaling pathway.
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Affiliation(s)
- Jun-Hei Chang
- Department of Medicine, Country Hospital, Taipei, Taiwan; Department of Biomedical Engineering, National Defense Medical Center, Taipei, Taiwan
| | - Chen-Chuan Cheng
- Department of Cardiology, Chi-Mei Medical Center, Tainan, Taiwan
| | - Yen-Yu Lu
- Division of Cardiology, Department of Internal Medicine, Sijhih Cathay General Hospital, New Taipei City, Taiwan; School of Medicine, College of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan
| | - Cheng-Chih Chung
- Division of Cardiology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yung-Hsin Yeh
- Cardiovascular Department, Chang Gung Memorial Hospital, Linkou, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yao-Chang Chen
- Department of Biomedical Engineering, National Defense Medical Center, Taipei, Taiwan
| | - Satoshi Higa
- Cardiac Electrophysiology and Pacing Laboratory, Division of Cardiovascular Medicine, Makiminato Central Hospital, Okinawa, Japan
| | - Shih-Ann Chen
- Heart Rhythm Center and Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Cardiovascular Center, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Yi-Jen Chen
- Cardiovascular Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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7
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Effect of liver transplantation on QT-interval prolongation and impact on mortality. Int J Cardiol 2020; 326:158-163. [PMID: 33186663 DOI: 10.1016/j.ijcard.2020.11.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/19/2020] [Accepted: 11/04/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND QT-interval prolongation is considered the electrophysiological hallmark of cirrhotic cardiomyopathy. However, the significance of QT-interval prolongation and how it is affected by liver transplantation (LT) remains unclear. METHODS Consecutive inpatients undergoing LT between 2010 and 2017 at a state-wide liver transplant center in Australia were included. Preoperative, early postoperative and long-term follow-up corrected QT-intervals (QTc) were manually measured by a cardiologist. QTc was calculated using the Bazett formula and QTc ≥440 milliseconds (ms) was considered prolonged. RESULTS Overall, 1111 ECG tracings among 408 patients (mean age 57 ± 12 years) were assessed. Pre-LT, 265 patients (65.0%) had QTc ≥440 ms and 24 patients (5.9%) had QTc ≥500 ms. In the early postoperative period, there was a significant increase in QTc compared to pre-LT (471 ± 39 vs. 452 ± 31 ms, p < 0.001) and 80 patients (20.3%) had QTc ≥500 ms. At a median of six months post-LT, there was significant reduction in mean QTc compared to pre-LT (430 ± 32 vs. 452 ± 31 ms; p < 0.001) with the QTc shortening in 73% of patients. QT-interval prolongation was not associated with postoperative complications or mortality at any time-point. CONCLUSION QT-interval prolongation is common in patients with liver cirrhosis and this metric normalized in the majority within six months post-LT. A significant increase in QTc was noted early post-LT, with over 20% demonstrating QTc ≥500 ms. QT-interval prolongation was not associated with post-transplant complications or mortality. Resolution of QT-interval prolongation suggests that this feature of cirrhotic cardiomyopathy may reverse post-transplantation.
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8
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Genetics and Epigenetics of Atrial Fibrillation. Int J Mol Sci 2020; 21:ijms21165717. [PMID: 32784971 PMCID: PMC7460853 DOI: 10.3390/ijms21165717] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/22/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022] Open
Abstract
Atrial fibrillation (AF) is known to be the most common supraventricular arrhythmia affecting up to 1% of the general population. Its prevalence exponentially increases with age and could reach up to 8% in the elderly population. The management of AF is a complex issue that is addressed by extensive ongoing basic and clinical research. AF centers around different types of disturbances, including ion channel dysfunction, Ca2+-handling abnormalities, and structural remodeling. Genome-wide association studies (GWAS) have uncovered over 100 genetic loci associated with AF. Most of these loci point to ion channels, distinct cardiac-enriched transcription factors, as well as to other regulatory genes. Recently, the discovery of post-transcriptional regulatory mechanisms, involving non-coding RNAs (especially microRNAs), DNA methylation, and histone modification, has allowed to decipher how a normal heart develops and which modifications are involved in reshaping the processes leading to arrhythmias. This review aims to provide a current state of the field regarding the identification and functional characterization of AF-related epigenetic regulatory networks
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9
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Chakraborty P, Rose RA, Nair K, Downar E, Nanthakumar K. The rationale for repurposing funny current inhibition for management of ventricular arrhythmia. Heart Rhythm 2020; 18:130-137. [PMID: 32738405 DOI: 10.1016/j.hrthm.2020.07.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/14/2020] [Accepted: 07/25/2020] [Indexed: 11/26/2022]
Abstract
Management of ventricular arrhythmia in structural heart disease is complicated by the toxicity of the limited antiarrhythmic options available. In others, proarrhythmia and deleterious hemodynamic and noncardiac effects prevent practical use. This necessitates new thinking in therapeutic agents for ventricular arrhythmia in structural heart disease. Ivabradine, a funny current (If) inhibitor, has proven safety in heart failure, angina, and inappropriate sinus tachycardia. Although it is commonly known that funny channels are primarily expressed in the sinoatrial node, atrioventricular node, and conducting system of the ventricle, ivabradine is known to exert effects on metabolism, ion homeostasis, and membrane electrophysiology of remodeled ventricular myocardium. This review considers novel concepts and evidence from clinical and experimental studies regarding this paradigm, with a potential role of ivabradine in ventricular arrhythmia.
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Affiliation(s)
- Praloy Chakraborty
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, An entity of the University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
| | - Krishnakumar Nair
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada
| | - Eugene Downar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada
| | - Kumaraswamy Nanthakumar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada.
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10
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Maj R, Iacopino S, Ströker E, Paparella G, Coutiño HE, Terasawa M, Varnavas V, Salghetti F, Osório T, Abugattas JP, Sieira J, Capulzini L, Brugada P, de Asmundis C, Chierchia GB. Mid-term outcome following second-generation cryoballoon ablation for atrial fibrillation in heart failure patients. J Cardiovasc Med (Hagerstown) 2019; 20:667-675. [DOI: 10.2459/jcm.0000000000000845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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11
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Martinez-Mateu L, Saiz J, Aromolaran AS. Differential Modulation of IK and ICa,L Channels in High-Fat Diet-Induced Obese Guinea Pig Atria. Front Physiol 2019; 10:1212. [PMID: 31607952 PMCID: PMC6773813 DOI: 10.3389/fphys.2019.01212] [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: 06/04/2019] [Accepted: 09/05/2019] [Indexed: 12/31/2022] Open
Abstract
Obesity mechanisms that make atrial tissue vulnerable to arrhythmia are poorly understood. Voltage-dependent potassium (IK, IKur, and IK1) and L-type calcium currents (ICa,L) are electrically relevant and represent key substrates for modulation in obesity. We investigated whether electrical remodeling produced by high-fat diet (HFD) alone or in concert with acute atrial stimulation were different. Electrophysiology was used to assess atrial electrical function after short-term HFD-feeding in guinea pigs. HFD atria displayed spontaneous beats, increased IK (IKr + IKs) and decreased ICa,L densities. Only with pacing did a reduction in IKur and increased IK1 phenotype emerge, leading to a further shortening of action potential duration. Computer modeling studies further indicate that the measured changes in potassium and calcium current densities contribute prominently to shortened atrial action potential duration in human heart. Our data are the first to show that multiple mechanisms (shortened action potential duration, early afterdepolarizations and increased incidence of spontaneous beats) may underlie initiation of supraventricular arrhythmias in obese guinea pig hearts. These results offer different mechanistic insights with implications for obese patients harboring supraventricular arrhythmias.
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Affiliation(s)
- Laura Martinez-Mateu
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Javier Saiz
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Ademuyiwa S Aromolaran
- Cardiac Electrophysiology and Metabolism Research Group, VA New York Harbor Healthcare System, Brooklyn, NY, United States.,Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, United States
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12
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Assessment of the relationship between reperfusion success and T-peak to T-end interval in patients with ST elevation myocardial infarction treated with percutaneous coronary intervention. Anatol J Cardiol 2019; 19:50-57. [PMID: 29339700 PMCID: PMC5864790 DOI: 10.14744/anatoljcardiol.2017.7949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Objective: T-peak–T-end (TPE) interval, which represents the dispersion of repolarization, is defined as the interval between the peak and end of the T-wave, and is associated with increased malignant ventricular arrhythmia and sudden cardiac death (SCD) in patients with ST elevation myocardial infarction (STEMI). Although prolonged TPE interval is associated with poor short- and long-term outcomes, even in patients with STEMI treated with successful primary percutaneous coronary intervention (pPCI), clinical, angiographic, and laboratory parameters that affect TPE remain to be elucidated. The aim of our study was to evaluate the potential relationship between prolonged TPE interval and reperfusion success using ST segment resolution (STR) in patients with STEMI undergoing pPCI. Methods: In the current study, 218 consecutive patients with STEMI who underwent pPCI were enrolled; after exclusion, 164 patients were included in the study population. Results: Patients were divided into two groups according to the presence of complete (STR%≥70) or incomplete (STR%<70) STR. Preprocedural corrected TPE (cTPEPRE;116±21 ms vs. 108±21 ms; p=0.027), postprocedural TPE (TPEPOST; 107±16 ms vs. 92±21 ms; p<0.001), and postprocedural cTPE (cTPEPOST; 119±19 ms vs. 102±17 ms; p<0.001) intervals were significantly longer in patients with incomplete STR than in patients with complete STR, whereas there was no statistically significant difference between the two groups in terms of pre- and postprocedural and corrected QT intervals. cTPEPRE and cTPEPOST were found to be independent predictors for incomplete STR. Conclusion: To our knowledge, this is the first study that evaluated the relationship between TPE interval and no-reflow defined by STR in patients with STEMI who were treated with pPCI.
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13
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Kulik Y, Jones R, Moughamian AJ, Whippen J, Davis GW. Dual separable feedback systems govern firing rate homeostasis. eLife 2019; 8:45717. [PMID: 30973325 PMCID: PMC6491091 DOI: 10.7554/elife.45717] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 04/10/2019] [Indexed: 12/02/2022] Open
Abstract
Firing rate homeostasis (FRH) stabilizes neural activity. A pervasive and intuitive theory argues that a single variable, calcium, is detected and stabilized through regulatory feedback. A prediction is that ion channel gene mutations with equivalent effects on neuronal excitability should invoke the same homeostatic response. In agreement, we demonstrate robust FRH following either elimination of Kv4/Shal protein or elimination of the Kv4/Shal conductance. However, the underlying homeostatic signaling mechanisms are distinct. Eliminating Shal protein invokes Krüppel-dependent rebalancing of ion channel gene expression including enhanced slo, Shab, and Shaker. By contrast, expression of these genes remains unchanged in animals harboring a CRISPR-engineered, Shal pore-blocking mutation where compensation is achieved by enhanced IKDR. These different homeostatic processes have distinct effects on homeostatic synaptic plasticity and animal behavior. We propose that FRH includes mechanisms of proteostatic feedback that act in parallel with activity-driven feedback, with implications for the pathophysiology of human channelopathies.
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Affiliation(s)
- Yelena Kulik
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Ryan Jones
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Armen J Moughamian
- Department of Neurology, University of California, San Francisco, San Francisco, United States
| | - Jenna Whippen
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
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14
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Fan X, Yu Y, Lan H, Ou X, Yang L, Li T, Cao J, Zeng X, Li M. Ca2+/Calmodulin-Dependent Protein Kinase II (CaMKII) Increases Small-Conductance Ca2+-Activated K+ Current in Patients with Chronic Atrial Fibrillation. Med Sci Monit 2018; 24:3011-3023. [PMID: 29737974 PMCID: PMC5963316 DOI: 10.12659/msm.909684] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background Increased small-conductance Ca2+-activated K+ current (SK), abnormal intracellular Ca2+ handling, and enhanced expression and activity of Ca2+/calmodulin-dependent protein kinase II (CaMKII) have been found in clinical and/or experimental models of atrial fibrillation (AF), but the cumulative effect of these phenomena and their mechanisms in AF are still unclear. This study aimed to test the hypothesis that CaMKII increases SK current in human chronic AF. Material/Methods Right atrial appendage tissues from patients with either sinus rhythm (SR) or AF and neonatal rat atrial myocytes were used. Patch clamp, qRT-PCR, and Western blotting techniques were used to perform the study. Results Compared to SR, the apamin-sensitive SK current (IKAS) was significantly increased, but the mRNA and protein levels of SK1, SK2, and SK3 were significantly decreased. In AF, the steady-state Ca2+ response curve of IKAS was shifted leftward and the [Ca2+]i level was significantly increased. CaMKII inhibitors (KN-93 or autocamtide-2-related inhibitory peptide (AIP)) reduced the IKAS in both AF and SR. The inhibitory effect of KN-93 or AIP on IKAS was greater in AF than in SR. The expression levels of calmodulin, CaMKII, and autophosphorylated CaMKII at Thr287 (but not at Thr286) were significantly increased in AF. Furthermore, KN-93 inhibited the expression of (Thr287)p-CaMKII and SK2 in neonatal rat atrial myocytes. Conclusions SK current is increased via the enhanced activation of CaMKII in patients with AF. This finding may explain the difference between SK current and channels expression in AF, and thus may provide a therapeutic target for AF.
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Affiliation(s)
- Xuehui Fan
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Yiyan Yu
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Huan Lan
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Xianhong Ou
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Lijie Yang
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Tao Li
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Jiming Cao
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Xiaorong Zeng
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
| | - Miaoling Li
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China (mainland)
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15
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Chowdhury RA, Tzortzis KN, Dupont E, Selvadurai S, Perbellini F, Cantwell CD, Ng FS, Simon AR, Terracciano CM, Peters NS. Concurrent micro- to macro-cardiac electrophysiology in myocyte cultures and human heart slices. Sci Rep 2018; 8:6947. [PMID: 29720607 PMCID: PMC5932023 DOI: 10.1038/s41598-018-25170-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/17/2018] [Indexed: 11/25/2022] Open
Abstract
The contact cardiac electrogram is derived from the extracellular manifestation of cellular action potentials and cell-to-cell communication. It is used to guide catheter based clinical procedures. Theoretically, the contact electrogram and the cellular action potential are directly related, and should change in conjunction with each other during arrhythmogenesis, however there is currently no methodology by which to concurrently record both electrograms and action potentials in the same preparation for direct validation of their relationships and their direct mechanistic links. We report a novel dual modality apparatus for concurrent electrogram and cellular action potential recording at a single cell level within multicellular preparations. We further demonstrate the capabilities of this system to validate the direct link between these two modalities of voltage recordings.
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Affiliation(s)
- Rasheda A Chowdhury
- Myocardial Function Section, National Heart and Lung Institute, Imperial College London, 4th floor Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK. .,ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK.
| | - Konstantinos N Tzortzis
- Myocardial Function Section, National Heart and Lung Institute, Imperial College London, 4th floor Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.,ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Emmanuel Dupont
- Myocardial Function Section, National Heart and Lung Institute, Imperial College London, 4th floor Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.,ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Shaun Selvadurai
- Myocardial Function Section, National Heart and Lung Institute, Imperial College London, 4th floor Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.,ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Filippo Perbellini
- Myocardial Function Section, National Heart and Lung Institute, Imperial College London, 4th floor Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Chris D Cantwell
- Department of Aeronautics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK. .,ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK.
| | - Fu Siong Ng
- Myocardial Function Section, National Heart and Lung Institute, Imperial College London, 4th floor Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.,ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Andre R Simon
- Department of Cardiothoracic Transplantation & Mechanical Circulatory Support, Royal Brompton and Harefield NHS Foundation Trust, London, UB9 6JH, UK
| | - Cesare M Terracciano
- Myocardial Function Section, National Heart and Lung Institute, Imperial College London, 4th floor Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Nicholas S Peters
- Myocardial Function Section, National Heart and Lung Institute, Imperial College London, 4th floor Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.,ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
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16
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Hu W, Xin Y, Zhang L, Hu J, Sun Y, Zhao Y. Iroquois Homeodomain transcription factors in ventricular conduction system and arrhythmia. Int J Med Sci 2018; 15:808-815. [PMID: 30008591 PMCID: PMC6036080 DOI: 10.7150/ijms.25140] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 04/29/2018] [Indexed: 02/05/2023] Open
Abstract
Iroquois homeobox genes, Irx, encode cardiac transcription factors, Irx1-6 in most mammals. These six transcription factors are expressed in different patterns mainly in the ventricular part of the heart. Existing researches show that Irx genes play key roles in the differentiation and development of ventricular conduction system and the establishment and maintenance of gradient expression of potassium channels, Kv4.2. Our main focus of this review is on the recent advances in the discovery of above-mentioned genes and the function of the encoding products, how Irx genes establish ventricular conduction system and regulate ventricular repolarization, how the individual and complementary functions can be verified to complement our cognition and leads to novel therapeutic approaches.
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Affiliation(s)
- Wenyu Hu
- Department of Cardiology, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Yanguo Xin
- Department of Cardiology, West China Hospital of Sichuan University, Chengdu, Sichuan 610041, China
| | - Lin Zhang
- Department of Cardiology, Jinqiu Hosipital Of Liaoning Province, Shenyang, Liaoning110001, China
| | - Jian Hu
- Department of Cardiology, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Yingxian Sun
- Department of Cardiology, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Yinan Zhao
- Department of Neurology, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
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17
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Zaza A, Ronchi C, Malfatto G. Arrhythmias and Heart Rate: Mechanisms and Significance of a Relationship. Arrhythm Electrophysiol Rev 2018; 7:232-237. [PMID: 30588310 DOI: 10.15420/aer.2018.12.3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 05/17/2018] [Indexed: 11/04/2022] Open
Abstract
The occurrence of arrhythmia is often related to basic heart rate. Prognostic significance is associated with such a relationship; furthermore, heart rate modulation may result as an ancillary effect of therapy, or be considered as a therapeutic tool. This review discusses the cellular mechanisms underlying arrhythmia occurrence during tachycardia or bradycardia, considering rate changes per se or as a mirror of autonomic modulation. Besides the influence of steady-state heart rate, dynamic aspects of changes in rate and autonomic balance are considered. The discussion leads to the conclusion that the prognostic significance of arrhythmia relationship with heart rate, and the consequence of heart rate on arrhythmogenesis, may vary according to the substrate present in the specific case and should be considered accordingly.
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Affiliation(s)
- Antonio Zaza
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi Milano-Bicocca Milan, Italy.,CARIM, Maastricht University Maastricht, the Netherlands
| | - Carlotta Ronchi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi Milano-Bicocca Milan, Italy
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18
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Long QQ, Wang H, Gao W, Fan Y, Li YF, Ma Y, Yang Y, Shi HJ, Chen BR, Meng HY, Wang QM, Wang F, Wang ZM, Wang LS. Long Noncoding RNA Kcna2 Antisense RNA Contributes to Ventricular Arrhythmias via Silencing Kcna2 in Rats With Congestive Heart Failure. J Am Heart Assoc 2017; 6:JAHA.117.005965. [PMID: 29263036 PMCID: PMC5778995 DOI: 10.1161/jaha.117.005965] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Congestive heart failure (CHF) is a common cardiovascular disease that is often accompanied by ventricular arrhythmias. The decrease of the slow component of the delayed rectifier potassium current (IKs) in CHF leads to action potential (AP) prolongation, and the IKs is an important contributor to the development of ventricular arrhythmias. However, the molecular mechanisms underlying ventricular arrhythmias are still unknown. METHODS AND RESULTS Kcna2 and Kcna2 antisense RNA (Kcna2 AS) transcript expression was measured in rat cardiac tissues using quantitative real-time reverse transcription-polymerase chain reaction and Western blotting. There was a 43% reduction in Kcna2 mRNA in the left ventricular myocardium of rats with CHF. Kcna2 knockdown in the heart decreased the IKs and prolonged APs in cardiomyocytes, consistent with the changes observed in heart failure. Conversely, Kcna2 overexpression in the heart significantly attenuated the CHF-induced decreases in the IKs, AP prolongation, and ventricular arrhythmias. Kcna2 AS was upregulated ≈1.7-fold in rats with CHF and with phenylephrine-induced cardiomyocyte hypertrophy. Kcna2 AS inhibition increased the CHF-induced downregulation of Kcna2. Consequently, Kcna2 AS mitigated the decrease in the IKs and the prolongation of APs in vivo and in vitro and reduced ventricular arrhythmias, as detected using electrocardiography. CONCLUSIONS Ventricular Kcna2 AS expression increases in rats with CHF and contributes to reduced IKs, prolonged APs, and the occurrence of ventricular arrhythmias by silencing Kcna2. Thus, Kcna2 AS may be a new target for the prevention and treatment of ventricular arrhythmias in patients with CHF.
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Affiliation(s)
- Qing-Qing Long
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hao Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Wei Gao
- Department of Geriatrics, Sir Run Run Hospital of Nanjing Medical University, Nanjing, China
| | - Yi Fan
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ya-Fei Li
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yao Ma
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yang Yang
- Department of Emergency and Intensive Care, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hao-Jie Shi
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Bing-Rui Chen
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hao-Yu Meng
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Qi-Ming Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Fang Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ze-Mu Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Lian-Sheng Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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19
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Zhao X, Gu T. Dysfunctional Hyperpolarization-Activated Cyclic Nucleotide-gated Ion Channels in Cardiac Diseases. Braz J Cardiovasc Surg 2017; 31:203-6. [PMID: 27556324 PMCID: PMC5062718 DOI: 10.5935/1678-9741.20160030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are reverse
voltage-dependent, and their activation depends on the hyperpolarization of the
membrane and may be directly or indirectly regulated by the cyclic adenosine
monophosphate (cAMP) or other signal-transduction cascades. The distribution,
quantity and activation states of HCN channels differ in tissues throughout the
body. Evidence exhibits that HCN channels play critical roles in the generation
and conduction of the electrical impulse and the physiopathological process of
some cardiac diseases. They may constitute promising drug targets in the
treatment of these cardiac diseases. Pharmacological treatment targeting HCN
channels is of benefit to these cardiac conditions.
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Affiliation(s)
- Xiaoqi Zhao
- Department of Cardiac Surgery ICU, First Affiliated Hospital, China Medical University, Shenyang, China
| | - Tianxiang Gu
- Department of Cardiac Surgery ICU, First Affiliated Hospital, China Medical University, Shenyang, China
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20
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Osadchii OE. Role of abnormal repolarization in the mechanism of cardiac arrhythmia. Acta Physiol (Oxf) 2017; 220 Suppl 712:1-71. [PMID: 28707396 DOI: 10.1111/apha.12902] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In cardiac patients, life-threatening tachyarrhythmia is often precipitated by abnormal changes in ventricular repolarization and refractoriness. Repolarization abnormalities typically evolve as a consequence of impaired function of outward K+ currents in cardiac myocytes, which may be caused by genetic defects or result from various acquired pathophysiological conditions, including electrical remodelling in cardiac disease, ion channel modulation by clinically used pharmacological agents, and systemic electrolyte disorders seen in heart failure, such as hypokalaemia. Cardiac electrical instability attributed to abnormal repolarization relies on the complex interplay between a provocative arrhythmic trigger and vulnerable arrhythmic substrate, with a central role played by the excessive prolongation of ventricular action potential duration, impaired intracellular Ca2+ handling, and slowed impulse conduction. This review outlines the electrical activity of ventricular myocytes in normal conditions and cardiac disease, describes classical electrophysiological mechanisms of cardiac arrhythmia, and provides an update on repolarization-related surrogates currently used to assess arrhythmic propensity, including spatial dispersion of repolarization, activation-repolarization coupling, electrical restitution, TRIaD (triangulation, reverse use dependence, instability, and dispersion), and the electromechanical window. This is followed by a discussion of the mechanisms that account for the dependence of arrhythmic vulnerability on the location of the ventricular pacing site. Finally, the review clarifies the electrophysiological basis for cardiac arrhythmia produced by hypokalaemia, and gives insight into the clinical importance and pathophysiology of drug-induced arrhythmia, with particular focus on class Ia (quinidine, procainamide) and Ic (flecainide) Na+ channel blockers, and class III antiarrhythmic agents that block the delayed rectifier K+ channel (dofetilide).
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Affiliation(s)
- O. E. Osadchii
- Department of Health Science and Technology; University of Aalborg; Aalborg Denmark
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21
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Luo L, Hu P, Miao C, Ma A, Wang T. Clenbuterol Attenuates hERG Channel by Promoting the Mature Channel Degradation. Int J Toxicol 2017; 36:314-324. [PMID: 28535735 DOI: 10.1177/1091581817710786] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Clenbuterol, a β2-selective adrenergic receptor agonist, is illicitly used in weight loss and performance enhancement and animal production. Increasing evidence demonstrates that clenbuterol induces various kinds of arrhythmias and QTc interval prolongation. However, little is known about the underlying mechanism. Most drugs are associated with QTc prolongation through interfering with human ether-a-go-go-related gene (hERG) K+ channels. The present study aims to investigate the effects and underlying mechanisms of clenbuterol on the hERG channel. HEK 293 cells were transfected with wild type and Y652A or F656A mutants of the hERG channel and treated with clenbuterol. The hERG current was recorded using whole-cell patch-clamp technique, and protein level was evaluated by Western blot. We found that clenbuterol decreases the mature form of the hERG protein at the cell membrane in a concentration- and time-dependent manner, without affecting the immature form. Correspondingly, clenbuterol chronic treatment reduced hERG current to a greater extent compared to acute treatment. In the presence of Brefeldin A (BFA), which was used to block hERG channel trafficking to cell membrane, clenbuterol reduced hERG on plasma membrane to a greater extent than BFA alone. In addition, the hERG channel's drug binding sites mutant Y652A and F656A abolished clenbuterol-mediated hERG reduction and current blockade. In conclusion, clenbuterol reduces hERG channel expression and current by promoting the channel degradation. The effect of clenbuterol on the hERG channel is related to the drug-binding sites, Tyr-652 and Phe-656, located on the S6 domain. This biophysical mechanism may underlie clenbuterol-induced QTc prolongation or arrhythmia.
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Affiliation(s)
- Ling Luo
- 1 Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Peijing Hu
- 1 Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Changqing Miao
- 1 Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Aiqun Ma
- 1 Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China.,2 Key Laboratory of Molecular Cardiology, Shaanxi, China.,3 Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, Shaanxi, China
| | - Tingzhong Wang
- 1 Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China.,2 Key Laboratory of Molecular Cardiology, Shaanxi, China.,3 Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, Shaanxi, China
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22
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Britton OJ, Bueno-Orovio A, Virág L, Varró A, Rodriguez B. The Electrogenic Na +/K + Pump Is a Key Determinant of Repolarization Abnormality Susceptibility in Human Ventricular Cardiomyocytes: A Population-Based Simulation Study. Front Physiol 2017; 8:278. [PMID: 28529489 PMCID: PMC5418229 DOI: 10.3389/fphys.2017.00278] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/18/2017] [Indexed: 11/23/2022] Open
Abstract
Background: Cellular repolarization abnormalities occur unpredictably due to disease and drug effects, and can occur even in cardiomyocytes that exhibit normal action potentials (AP) under control conditions. Variability in ion channel densities may explain differences in this susceptibility to repolarization abnormalities. Here, we quantify the importance of key ionic mechanisms determining repolarization abnormalities following ionic block in human cardiomyocytes yielding normal APs under control conditions. Methods and Results: Sixty two AP recordings from non-diseased human heart preparations were used to construct a population of human ventricular models with normal APs and a wide range of ion channel densities. Multichannel ionic block was applied to investigate susceptibility to repolarization abnormalities. IKr block was necessary for the development of repolarization abnormalities. Models that developed repolarization abnormalities over the widest range of blocks possessed low Na+/K+ pump conductance below 50% of baseline, and ICaL conductance above 70% of baseline. Furthermore, INaK made the second largest contribution to repolarizing current in control simulations and the largest contribution under 75% IKr block. Reversing intracellular Na+ overload caused by reduced INaK was not sufficient to prevent abnormalities in models with low Na+/K+ pump conductance, while returning Na+/K+ pump conductance to normal substantially reduced abnormality occurrence, indicating INaK is an important repolarization current. Conclusions: INaK is an important determinant of repolarization abnormality susceptibility in human ventricular cardiomyocytes, through its contribution to repolarization current rather than homeostasis. While we found IKr block to be necessary for repolarization abnormalities to occur, INaK decrease, as in disease, may amplify the pro-arrhythmic risk of drug-induced IKr block in humans.
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Affiliation(s)
| | | | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of SzegedSzeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of SzegedSzeged, Hungary
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Epigallocatechin-3-gallate modulates arrhythmogenic activity and calcium homeostasis of left atrium. Int J Cardiol 2017; 236:174-180. [PMID: 28117139 DOI: 10.1016/j.ijcard.2017.01.090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is the commonest sustained arrhythmia, and increases the risk of stroke, heart failure, and mortality. Calcium (Ca2+) overload and oxidative stress are thought to participate in the pathogenesis of AF. Epigallocatechin-3-gallate (EGCG) has an antioxidative effect and been shown to be beneficial in promoting cardiovascular health. However, it is not clear if EGCG directly modulates the electrophysiological characteristics and Ca2+ homeostasis of the left atrium (LA). METHODS AND RESULTS Conventional microelectrodes, whole-cell patch-clamp, and Fluo-3 fluorometric ratio technique were performed using the isolated rabbit LA preparations or isolated single LA cardiomyocytes before and after EGCG treatment. EGCG (0.01, 0.1, 1, and 10μM) which concentration-dependently decreased the APD20 by 13±8%, 25±5%, 31±6%, and 37±5%, APD50 by 9±8%, 22±6%, 32±7%, and 40±4%, and APD90 by 2±12%, 9±8%, 24±10%, and 34±5% in LA preparations. EGCG (0.1μM) decreased the late sodium (Na+) current, L-type Ca2+ current, nickel-sensitive Na+-Ca2+ exchanger current, and transient outward current, but did not change the Na+ current and ultra-rapid delayed rectifier potassium current in LA cardiomyocytes. EGCG decreased intracellular Ca2+ transient and sarcoplasmic reticulum Ca2+ content in LA cardiomyocytes. Furthermore, EGCG decreased isoproterenol (ISO, 1μM)-induced burst firing. KT5823 (1μM) or KN93 (1μM) decreased the incidences of ISO-induced LA burst firing, which became lower with EGCG treatment. H89 (10μM) and KN92 (1μM) did not suppress the incidence of ISO-induced LA burst firing. However, EGCG decreased the incidences of ISO-induced LA burst firing in the presence of H89 or KN92. CONCLUSION EGCG directly regulates LA electrophysiological characteristics and Ca2+ homeostasis, and suppresses ISO-induced atrial arrhythmogenesis through inhibiting Ca2+/calmodulin or cGMP-dependent protein kinases.
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Chahal AA, Somers VK. Ion Channel Remodeling-A Potential Mechanism Linking Sleep Apnea and Sudden Cardiac Death. J Am Heart Assoc 2016; 5:JAHA.116.004195. [PMID: 27543309 PMCID: PMC5015316 DOI: 10.1161/jaha.116.004195] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Anwar Ahmed Chahal
- Cardiovascular Diseases, Mayo Clinic, Rochester, MN Mayo Graduate School, Rochester, MN Specialty Registrar, Cardiology and Internal Medicine, London Deanery, University College London Partners, London, UK
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Molina CE, Heijman J, Dobrev D. Differences in Left Versus Right Ventricular Electrophysiological Properties in Cardiac Dysfunction and Arrhythmogenesis. Arrhythm Electrophysiol Rev 2016; 5:14-9. [PMID: 27403288 DOI: 10.15420/aer.2016.8.2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A wide range of ion channels, transporters, signaling pathways and tissue structure at a microscopic and macroscopic scale regulate the electrophysiological activity of the heart. Each region of the heart has optimised these properties based on its specific role during the cardiac cycle, leading to well-established differences in electrophysiology, Ca(2+) handling and tissue structure between atria and ventricles and between different layers of the ventricular wall. Similarly, the right ventricle (RV) and left ventricle (LV) have different embryological, structural, metabolic and electrophysiological features, but whether interventricular differences promote differential remodeling leading to arrhythmias is not well understood. In this article, we will summarise the available data on intrinsic differences between LV and RV electrophysiology and indicate how these differences affect cardiac function. Furthermore, we will discuss the differential remodeling of both chambers in pathological conditions and its potential impact on arrhythmogenesis.
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Affiliation(s)
- Cristina E Molina
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Jordi Heijman
- Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
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Ad N, Holmes SD, Shuman DJ, Pritchard G. Impact of Atrial Fibrillation Duration on the Success of First-Time Concomitant Cox Maze Procedures. Ann Thorac Surg 2015. [DOI: 10.1016/j.athoracsur.2015.04.105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Yang D, Wang T, Ni Y, Song B, Ning F, Hu P, Luo L, Wang Y, Ma A. Apamin-Sensitive K+ Current Upregulation in Volume-Overload Heart Failure is Associated with the Decreased Interaction of CK2 with SK2. J Membr Biol 2015; 248:1181-9. [PMID: 26362340 DOI: 10.1007/s00232-015-9839-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 09/04/2015] [Indexed: 12/20/2022]
Abstract
Recent studies have shown that the sensitivity of apamin-sensitive K(+) current (I KAS, mediated by apamin-sensitive small conductance calcium-activated potassium channels subunits) to intracellular Ca(2+) is increased in heart failure (HF), leading to I KAS upregulation, action potential duration shortening, early after depolarization, and recurrent spontaneous ventricular fibrillation. We hypothesized that casein kinase 2 (CK2) interacted with small conductance calcium-activated potassium channels (SK) is decreased in HF, and protein phosphatase 2A (PP2A) is increased on the opposite, upregulating the sensitivity of I KAS to intracellular Ca(2+) in HF. Rat model of volume-overload HF was established by an abdominal arteriovenous fistula procedure. The expression of SK channels, PP2A and CK2 was detected by Western blot analysis. Interaction and colocalization of CK2 with SK channel were detected by co-immunoprecipitation analysis and double immunofluorescence staining. In HF rat left ventricle, SK3 was increased by 100 % (P < 0.05), and SK2 was not significantly changed. PP2A protein was increased by 94.7 % in HF rats (P < 0.05), whereas the level of CK2 was almost unchanged. We found that CK2 colocalized with SK2 and SK3 in rat left ventricle. With anti-CK2α antibody, SK2 and SK3 were immunoprecipitated, the level of precipitated SK2 decreased by half, whereas precipitated SK3 was almost unchanged. In conclusion, the increased expression of total PP2A and decreased interaction of CK2 with SK2 may underlie enhanced sensitivity of I KAS to intracellular Ca(2+) in volume-overload HF rat.
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Affiliation(s)
- Dandan Yang
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shaanxi, China
| | - Tingzhong Wang
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shaanxi, China.,Shaanxi Key Laboratory of Molecular Cardiology (Xi'an Jiaotong University), Xi'an, 710061, Shaanxi, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, China
| | - Yajuan Ni
- Department of Cardiovascular Medicine, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Bingxue Song
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shaanxi, China
| | - Feifei Ning
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shaanxi, China
| | - Peijing Hu
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shaanxi, China
| | - Ling Luo
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shaanxi, China
| | - Ya Wang
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shaanxi, China
| | - Aiqun Ma
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shaanxi, China. .,Shaanxi Key Laboratory of Molecular Cardiology (Xi'an Jiaotong University), Xi'an, 710061, Shaanxi, China. .,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, China.
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Orosz A, Baczkó I, Nagy V, Gavallér H, Csanády M, Forster T, Papp JG, Varró A, Lengyel C, Sepp R. Short-term beat-to-beat variability of the QT interval is increased and correlates with parameters of left ventricular hypertrophy in patients with hypertrophic cardiomyopathy. Can J Physiol Pharmacol 2015; 93:765-72. [DOI: 10.1139/cjpp-2014-0526] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Stratification models for the prediction of sudden cardiac death (SCD) are inappropriate in patients with hypertrophic cardiomyopathy (HCM). We investigated conventional electrocardiogram (ECG) repolarization parameters and the beat-to-beat short-term QT interval variability (QT-STV), a new parameter of proarrhythmic risk, in 37 patients with HCM (21 males, average age 48 ± 15 years). Resting ECGs were recorded for 5 min and the frequency corrected QT interval (QTc), QT dispersion (QTd), beat-to-beat short-term variability of QT interval (QT-STV), and the duration of terminal part of T waves (Tpeak–Tend) were calculated. While all repolarization parameters were significantly increased in patients with HCM compared with the controls (QTc, 488 ± 61 vs. 434 ± 23 ms, p < 0.0001; QT-STV, 4.5 ± 2 vs. 3.2 ± 1 ms, p = 0.0002; Tpeak–Tend duration, 107 ± 27 vs. 91 ± 10 ms, p = 0.0015; QTd, 47 ± 17 vs. 34 ± 9 ms, p = 0.0002), QT-STV had the highest relative increase (+41%). QT-STV also showed the best correlation with indices of left ventricular (LV) hypertrophy, i.e., maximal LV wall thickness normalized for body surface area (BSA; r = 0.461, p = 0.004) or LV mass (determined by cardiac magnetic resonance imaging) normalized for BSA (r = 0.455, p = 0.015). In summary, beat-to-beat QT-STV showed the most marked increase in patients with HCM and may represent a novel marker that merits further testing for increased SCD risk in HCM.
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Affiliation(s)
- Andrea Orosz
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary
| | - Viktória Nagy
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
| | - Henriette Gavallér
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
- Diagnoscan Hungary Ltd., Semmelweis utca 6, 6725 Szeged, Hungary
| | - Miklós Csanády
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
| | - Tamás Forster
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
| | - Julius Gy. Papp
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - Csaba Lengyel
- First Department of Internal Medicine, University of Szeged, Hungary
| | - Róbert Sepp
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
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Atrial overexpression of angiotensin-converting enzyme 2 improves the canine rapid atrial pacing-induced structural and electrical remodeling. Fan, ACE2 improves atrial substrate remodeling. Basic Res Cardiol 2015; 110:45. [PMID: 26143546 PMCID: PMC7101981 DOI: 10.1007/s00395-015-0499-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 05/17/2015] [Accepted: 05/26/2015] [Indexed: 01/30/2023]
Abstract
The purpose of this study was to investigate whether atrial overexpression of angiotensin-converting enzyme 2 (ACE2) by homogeneous transmural atrial gene transfer can reverse atrial remodeling and its mechanisms in a canine atrial-pacing model. Twenty-eight mongrel dogs were randomly divided into four groups: Sham-operated, AF-control, gene therapy with adenovirus-enhanced green fluorescent protein (Ad-EGFP) and gene therapy with Ad-ACE2 (Ad-ACE2) (n = 7 per subgroup). AF was induced in all dogs except the Sham-operated group by rapid atrial pacing at 450 beats/min for 2 weeks. Ad-EGFP and Ad-ACE2 group then received epicardial gene painting. Three weeks after gene transfer, all animals except the Sham group underwent rapid atrial pacing for another 3 weeks and then invasive electrophysiological, histological and molecular studies. The Ad-ACE2 group showed an increased ACE2 and Angiotensin-(1–7) expression, and decreased Angiotensin II expression in comparison with Ad-EGFP and AF-control group. ACE2 overexpression attenuated rapid atrial pacing-induced increase in activated extracellular signal-regulated kinases and mitogen-activated protein kinases (MAPKs) levels, and decrease in MAPK phosphatase 1(MKP-1) level, resulting in attenuation of atrial fibrosis collagen protein markers and transforming growth factor-β1. Additionally, ACE2 overexpression also modulated the tachypacing-induced up-regulation of connexin 40, down-regulation of connexin 43 and Kv4.2, and significantly decreased the inducibility and duration of AF. ACE2 overexpression could shift the renin–angiotensin system balance towards the protective axis, attenuate cardiac fibrosis remodeling associated with up-regulation of MKP-1 and reduction of MAPKs activities, modulate tachypacing-induced ion channels and connexin remodeling, and subsequently reduce the inducibility and duration of AF.
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Stimers JR, Song L, Rusch NJ, Rhee SW. Overexpression of the Large-Conductance, Ca2+-Activated K+ (BK) Channel Shortens Action Potential Duration in HL-1 Cardiomyocytes. PLoS One 2015; 10:e0130588. [PMID: 26091273 PMCID: PMC4474436 DOI: 10.1371/journal.pone.0130588] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 05/22/2015] [Indexed: 12/29/2022] Open
Abstract
Long QT syndrome is characterized by a prolongation of the interval between the Q wave and the T wave on the electrocardiogram. This abnormality reflects a prolongation of the ventricular action potential caused by a number of genetic mutations or a variety of drugs. Since effective treatments are unavailable, we explored the possibility of using cardiac expression of the large-conductance, Ca2+-activated K+ (BK) channel to shorten action potential duration (APD). We hypothesized that expression of the pore-forming α subunit of human BK channels (hBKα) in HL-1 cells would shorten action potential duration in this mouse atrial cell line. Expression of hBKα had minimal effects on expression levels of other ion channels with the exception of a small but significant reduction in Kv11.1. Patch-clamped hBKα expressing HL-1 cells exhibited an outward voltage- and Ca2+-sensitive K+ current, which was inhibited by the BK channel blocker iberiotoxin (100 nM). This BK current phenotype was not detected in untransfected HL-1 cells or in HL-1 null cells sham-transfected with an empty vector. Importantly, APD in hBKα-expressing HL-1 cells averaged 14.3 ± 2.8 ms (n = 10), which represented a 53% reduction in APD compared to HL-1 null cells lacking BKα expression. APD in the latter cells averaged 31.0 ± 5.1 ms (n = 13). The shortened APD in hBKα-expressing cells was restored to normal duration by 100 nM iberiotoxin, suggesting that a repolarizing K+ current attributed to BK channels accounted for action potential shortening. These findings provide initial proof-of-concept that the introduction of hBKα channels into a cardiac cell line can shorten APD, and raise the possibility that gene-based interventions to increase hBKα channels in cardiac cells may hold promise as a therapeutic strategy for long QT syndrome.
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Affiliation(s)
- Joseph R. Stimers
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- * E-mail:
| | - Li Song
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Nancy J. Rusch
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Sung W. Rhee
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
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Herrmann S, Schnorr S, Ludwig A. HCN channels--modulators of cardiac and neuronal excitability. Int J Mol Sci 2015; 16:1429-47. [PMID: 25580535 PMCID: PMC4307311 DOI: 10.3390/ijms16011429] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 12/31/2014] [Indexed: 01/06/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels comprise a family of cation channels activated by hyperpolarized membrane potentials and stimulated by intracellular cyclic nucleotides. The four members of this family, HCN1-4, show distinct biophysical properties which are most evident in the kinetics of activation and deactivation, the sensitivity towards cyclic nucleotides and the modulation by tyrosine phosphorylation. The four isoforms are differentially expressed in various excitable tissues. This review will mainly focus on recent insights into the functional role of the channels apart from their classic role as pacemakers. The importance of HCN channels in the cardiac ventricle and ventricular hypertrophy will be discussed. In addition, their functional significance in the peripheral nervous system and nociception will be examined. The data, which are mainly derived from studies using transgenic mice, suggest that HCN channels contribute significantly to cellular excitability in these tissues. Remarkably, the impact of the channels is clearly more pronounced in pathophysiological states including ventricular hypertrophy as well as neural inflammation and neuropathy suggesting that HCN channels may constitute promising drug targets in the treatment of these conditions. This perspective as well as the current therapeutic use of HCN blockers will also be addressed.
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Affiliation(s)
- Stefan Herrmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Sabine Schnorr
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Andreas Ludwig
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
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Ovechkin AO, Vaykshnorayte MA, Sedova K, Shumikhin KV, Arteyeva NV, Azarov JE. Functional role of myocardial electrical remodeling in diabetic rabbits. Can J Physiol Pharmacol 2014; 93:245-52. [PMID: 25666101 DOI: 10.1139/cjpp-2014-0293] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The objective of the study was to investigate the role of electrical remodeling of the ventricular myocardium in hemodynamic impairment and the development of arrhythmogenic substrate. Experiments were conducted with 11 healthy and 12 diabetic (alloxan model, 4 weeks) rabbits. Left ventricular pressure was monitored and unipolar electrograms were recorded from 64 epicardial leads. Aortic banding was used to provoke arrhythmia. The diabetic rabbits had prolonged QTc, with activation-recovery intervals (surrogates for repolarization durations) being relatively short on the left ventricular base and long on the anterior apical portions of both ventricles (P < 0.05). In the diabetic rabbits, a negative correlation (-0.726 to -0.817) was observed between dP/dt(max), dP/dt(min), and repolarization dispersions. Under conditions of systolic overload (5 min), tachyarrhythmias were equally rare and the QTc and activation-recovery intervals were shortened in both groups (P < 0.05), whereas QRS was prolonged in the diabetic rabbits only. The repolarization shortening was more pronounced on the apex, which led to the development of apicobasal and interventricular end of repolarization gradients in the healthy animals, and to the flattening of the repolarization profile in the diabetic group. Thus, the diabetes-related pattern of ventricular repolarization was associated with inotropic and lusitropic impairment of the cardiac pump function.
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Affiliation(s)
- Alexey O Ovechkin
- Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 50 Pervomayskaya Street, 167982 Syktyvkar, Russia., First Department of Internal Diseases of Komi Branch of Kirov State Medical Academy, 11 Babushkin Street, Syktyvkar 167000, Russia., Department of Physiology, Medical Institute of Syktyvkar State University, 11 Babushkin Street, Syktyvkar 167000, Russia
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Coronel R, Wilders R, Verkerk AO, Wiegerinck RF, Benoist D, Bernus O. Electrophysiological changes in heart failure and their implications for arrhythmogenesis. Biochim Biophys Acta Mol Basis Dis 2013; 1832:2432-41. [DOI: 10.1016/j.bbadis.2013.04.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 04/01/2013] [Indexed: 01/07/2023]
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Zafalon N, Oshiyama NF, Bassani JWM, Bassani RA. Muscarinic stimulation and pinacidil produce similar facilitation of tachyarrhythmia induction in rat isolated atria. J Mol Cell Cardiol 2013; 65:120-6. [PMID: 24140800 DOI: 10.1016/j.yjmcc.2013.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 10/09/2013] [Indexed: 10/26/2022]
Abstract
Atrial tachyarrhythmias, the most common type of cardiac arrhythmias, are associated with greater stroke risk. Muscarinic cholinergic agonists have been shown to facilitate atrial tachyarrhythmia maintenance in the absence of cardiac disease. This has been attributed to action potential shortening, which enhances myocardial electrical anisotropy, and thus creates a substrate for reentrant excitation. In this study, we describe a similar effect of the ATP-sensitive K(+) channel (KATP) opener pinacidil on tachyarrhythmia induction in isolated rat atria. Pinacidil, which activates a weakly inwardly-rectifying current in isolated atrial myocytes, enhanced arrhythmia induction in the right and left atria. This effect was abolished by the KATP blocker glibenclamide, but not by atropine, which rules out a possible indirect effect due to stimulation of acetylcholine release. However, pinacidil attenuated carbachol-induced tachyarrhythmia facilitation, which may indicate that the action of these agonists converges to a common cellular mechanism. Both agonists caused marked action potential shortening in isolated atrial myocytes. Moreover, during arrhythmia in the presence of pinacidil and carbachol, the atrial vectorelectrographic patterns were similar and consistent with reentrant propagation of the electrical activity. From these results, we conclude that the KATP channel opening is pro-arrhythmic in atrial tissue, which may pose as an additional risk in the scenario of myocardial hypoxia. Moreover, the similarity of the electrophysiological effects of pinacidil and carbachol is suggestive that the sole increase in background K(+) conductance is sufficient for atrial tachyarrhythmia facilitation.
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Affiliation(s)
- Nivaldo Zafalon
- Department of Biomedical Engineering/FEEC, University of Campinas, Caixa Postal 6040, 13084-971 Campinas, SP, Brazil.
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Xi Y, Wu G, Ai T, Cheng N, Kalisnik JM, Sun J, Abbasi S, Yang D, Fan C, Yuan X, Wang S, Elayda M, Gregoric ID, Kantharia BK, Lin SF, Cheng J. Ionic Mechanisms Underlying the Effects of Vasoactive Intestinal Polypeptide on Canine Atrial Myocardium. Circ Arrhythm Electrophysiol 2013; 6:976-83. [DOI: 10.1161/circep.113.000518] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yutao Xi
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Geru Wu
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Tomohiko Ai
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Nancy Cheng
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Jurij Matija Kalisnik
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Junping Sun
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Shahrzad Abbasi
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Donghui Yang
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Christopher Fan
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Xiaojing Yuan
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Suwei Wang
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - MacArthur Elayda
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Igor D. Gregoric
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Bharat K. Kantharia
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Shien-Fong Lin
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
| | - Jie Cheng
- From the Texas Heart Institute/St. Luke’s Episcopal Hospital, Houston (Y.X., G.W., N.C., J.M.K., J.S., S.A., D.Y., C.F., S.W., M.E., J.C.); Krannert Institute of Cardiology, Indiana University, Indianapolis (T.A., S.-F.L.); Engineering Technology Department, University of Houston, TX (X.Y.); and Center for Advanced Heart Failure (I.D.G.) and Section of Cardiology (Y.X., B.K.K., J.C.), University of Texas Health Science Center at Houston
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Li X, Wang T, Han K, Zhuo X, Lu Q, Ma A. Bisoprolol reverses down-regulation of potassium channel proteins in ventricular tissues of rabbits with heart failure. J Biomed Res 2013; 25:274-9. [PMID: 23554701 PMCID: PMC3597065 DOI: 10.1016/s1674-8301(11)60037-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 04/28/2011] [Accepted: 05/14/2011] [Indexed: 11/24/2022] Open
Abstract
Remodeling of ion channels is an important mechanism of arrhythmia induced by heart failure (HF). We investigated the expression of potassium channel encoding genes in the ventricles of rabbit established by volume-overload operation followed with pressure-overload. The reversible effect of these changes with bisoprolol was also evaluated. The HF group exhibited left ventricular enlargement, systolic dysfunction, prolongation of corrected QT interval (QTc), and increased plasma brain natriuretic peptide levels in the HF rabbits. Several potassium channel subunit encoding genes were consistently down-regulated in the HF rabbits. After bisoprolol treatment, heart function was improved significantly and QTc was shortened. Additionally, the mRNA expression of potassium channel subunit genes could be partially reversed. The down-regulated expression of potassium channel subunits Kv4.3, Kv1.4, KvLQT1, minK and Kir 2.1 may contribute to the prolongation of action potential duration in the heart of rabbits induced by volume combined with pressure overload HF. Bisoprolol could partially reverse these down-regulations and improve heart function.
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Affiliation(s)
- Xi Li
- Department of Cardiovascular Medicine, the First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
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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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De Jong AM, Maass AH, Oberdorf-Maass SU, De Boer RA, Van Gilst WH, Van Gelder IC. Cyclical stretch induces structural changes in atrial myocytes. J Cell Mol Med 2013; 17:743-53. [PMID: 23617620 PMCID: PMC3823178 DOI: 10.1111/jcmm.12064] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 03/19/2013] [Indexed: 01/15/2023] Open
Abstract
Atrial fibrillation (AF) often occurs in the presence of an underlying disease. These underlying diseases cause atrial remodelling, which make the atria more susceptible to AF. Stretch is an important mediator in the remodelling process. The aim of this study was to develop an atrial cell culture model mimicking remodelling due to atrial pressure overload. Neonatal rat atrial cardiomyocytes (NRAM) were cultured and subjected to cyclical stretch on elastic membranes. Stretching with 1 Hz and 15% elongation for 30 min. resulted in increased expression of immediate early genes and phosphorylation of Erk and p38. A 24-hr stretch period resulted in hypertrophy-related changes including increased cell diameter, reinduction of the foetal gene program and cell death. No evidence of apoptosis was observed. Expression of atrial natriuretic peptide, brain natriuretic peptide and growth differentiation factor-15 was increased, and calcineurin signalling was activated. Expression of several potassium channels was decreased, suggesting electrical remodelling. Atrial stretch-induced change in skeletal α-actin expression was inhibited by pravastatin, but not by eplerenone or losartan. Stretch of NRAM results in elevation of stress markers, changes related to hypertrophy and dedifferentiation, electrical remodelling and cell death. This model can contribute to investigating the mechanisms involved in the remodelling process caused by stretch and to the testing of pharmaceutical agents.
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Affiliation(s)
- Anne Margreet De Jong
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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40
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Holzem KM, Efimov IR. Arrhythmogenic remodelling of activation and repolarization in the failing human heart. Europace 2013; 14 Suppl 5:v50-v57. [PMID: 23104915 DOI: 10.1093/europace/eus275] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Heart failure is a major cause of disability and death worldwide, and approximately half of heart failure-related deaths are sudden and presumably due to ventricular arrhythmias. Patients with heart failure have been shown to be at 6- to 9-fold increased risk of sudden cardiac death compared to the general population. (AHA. Heart Disease and Stroke Statistics-2003 Update. Heart and Stroke Facts. Dallas, TX: American Heart Association; 2002) Thus, electrophysiological remodelling associated with heart failure is a leading cause of disease mortality and has been a major investigational focus examined using many animal models of heart failure. While these studies have provided an important foundation for understanding the arrhythmogenic pathophysiology of heart failure, the need for corroborating studies conducted on human heart tissue has been increasingly recognized. Many human heart studies of conduction and repolarization remodelling have now been published and shed some light on important, potentially arrhythmogenic, changes in human heart failure. These studies are being conducted at multiple experimental scales from isolated cells to whole-tissue preparations and have provided insight into regulatory mechanisms such as decreased protein expression, alternative mRNA splicing of ion channel genes, and defective cellular trafficking. Further investigations of heart failure in the human myocardium will be essential for determining possible therapeutic targets to prevent arrhythmia in heart failure and for facilitating the translation of basic research findings to the clinical realm.
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Affiliation(s)
- Katherine M Holzem
- Department of Biomedical Engineering, Washington University in St Louis, One Brookings Drive, St Louis, MO 63130, USA
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Electrical storm: recent pathophysiological insights and therapeutic consequences. Basic Res Cardiol 2013; 108:336. [DOI: 10.1007/s00395-013-0336-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 01/29/2013] [Accepted: 02/04/2013] [Indexed: 01/01/2023]
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Franco D. Wiring the developing heart: a serious matter for adulthood. Cardiovasc Res 2013; 97:4-5. [PMID: 23175775 DOI: 10.1093/cvr/cvs341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Store-dependent deactivation: cooling the chain-reaction of myocardial calcium signaling. J Mol Cell Cardiol 2012; 58:77-83. [PMID: 23108187 DOI: 10.1016/j.yjmcc.2012.10.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/11/2012] [Accepted: 10/21/2012] [Indexed: 01/08/2023]
Abstract
In heart cells, Ca(2+) released from the internal storage unit, the sarcoplasmic reticulum (SR) through ryanodine receptor (RyR2) channels is the predominant determinant of cardiac contractility. Evidence obtained in recent years suggests that SR Ca(2+) release is tightly regulated not only by cytosolic Ca(2+) but also by intra-store Ca(2+) concentration. Specifically, Ca(2+)-induced Ca(2+) release (CICR) that relies on auto-catalytic action of Ca(2+) at the cytosolic side of RyR2s is precisely balanced and counteracted by RyR2 deactivation dependent on a reciprocal decrease of Ca(2+) at the luminal side of RyR2s. Dysregulation of this inherently unstable Ca(2+) signaling is considered to be an underlying cause of triggered arrhythmias, and is associated with genetic and acquired forms of sudden cardiac death. In this article, we present an overview of recent advances in our understanding of the regulatory role luminal Ca(2+) plays in Ca(2+) handling, with a particular emphasis on the role of Ca(2+)release refractoriness in aberrant Ca(2+) release.
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González de la Fuente M, Barana A, Gómez R, Amorós I, Dolz-Gaitón P, Sacristán S, Atienza F, Pita A, Pinto Á, Fernández-Avilés F, Caballero R, Tamargo J, Delpón E. Chronic atrial fibrillation up-regulates β1-Adrenoceptors affecting repolarizing currents and action potential duration. Cardiovasc Res 2012; 97:379-88. [DOI: 10.1093/cvr/cvs313] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Partemi S, Batlle M, Berne P, Berruezo A, Campos B, Mont L, Riuró H, Roig E, Pérez-Villa F, Ortiz J, Pascali VL, Oliva A, Brugada R, Brugada J. Analysis of the arrhythmogenic substrate in human heart failure. Cardiovasc Pathol 2012; 22:133-40. [PMID: 23036686 DOI: 10.1016/j.carpath.2012.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 07/26/2012] [Accepted: 07/26/2012] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The mechanism of sudden cardiac death in patients with heart failure (HF) is uncertain. Both electrical instability and structural remodelling could be factors that lead to fatal arrhythmias. We sought to analyse the expression of the sodium (SCN5A) and potassium (KCND3) channels as well as the fibrosis content in the ventricles of human HF and of non-diseased hearts under different post-mortem intervals. METHODS AND RESULTS We analysed normal human hearts as controls [n=20 for the right ventricle (RV) and n=13 for the left ventricle (LV)] and human hearts from HF patients, which were obtained at the time of cardiac transplantation, as cases (n=48 for RV and n=34 for LV). Transcription of the SCN5A (probes SCN5A E4-5, E11-12, and E28) and KCND3 channels and of COLLAGEN I and III were assayed by real-time polymerase chain reaction. In addition, paraffin sections were used to analyse the percentage of collagen deposition in both cases and controls. KCND3 mRNA expression in the LV was lower in the cases than in controls (P<.001). Higher levels of SCN5A mRNA were found in the HF samples when analysed with probe SCN5A E4-5 (P<.05). SCN5A expression was lower in the controls with longer post-mortem interval (n=4) than in the controls with a shorter post- mortem interval (n=16, P<.01). KCND3 mRNA levels were also different between the two control groups (P<.05). Collagen deposition was higher in the LV tissues of the cases when compared to controls (P<.001), and it was higher in the LV from HF patients than in the RV (P<.05). Furthermore, collagen deposition was higher in the LV samples from patients with implanted cardiac defibrillator (ICD) therapy than in the LV of patients with no ICD therapy (P<.05). CONCLUSIONS These data indicate that ionic and structural remodelling could be pathophysiological mechanisms of cardiac arrhythmias in HF patients.
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Affiliation(s)
- Sara Partemi
- Thorax Institute-Hospital Clínic, University of Barcelona (Cardiology Department) Institute of Biomedical Research August Pi iSunyer (IDIBAPS), Spain.
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Osadchii OE. Impact of Na+ channel blockers on transmural dispersion of refractoriness and arrhythmic susceptibility in guinea-pig left ventricle. Eur J Pharmacol 2012; 691:173-81. [DOI: 10.1016/j.ejphar.2012.07.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 06/27/2012] [Accepted: 07/02/2012] [Indexed: 02/03/2023]
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Erikssen G, Liestøl K, Gullestad L, Haugaa KH, Bendz B, Amlie JP. The terminal part of the QT interval (T peak to T end): a predictor of mortality after acute myocardial infarction. Ann Noninvasive Electrocardiol 2012; 17:85-94. [PMID: 22537325 DOI: 10.1111/j.1542-474x.2012.00493.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The terminal part of the QT interval (T peak to T end; Tp-e)-an index for dispersion of cardiac repolarization-is often prolonged in patients experiencing malignant ventricular arrhythmias after acute myocardial infarction (AMI). We wanted to explore whether high Tp-e might predict mortality or fatal arrhythmia post-AMI. METHODS Tp-e was measured prospectively in 1359/1384 (98.2%) consecutive patients with ST elevation (n = 525) or non-ST elevation (n = 859) myocardial infarction (STEMI or NSTEMI) admitted for coronary angiography. RESULTS Tp-e was significantly correlated with age, heart rate (HR), heart failure, LVEF, creatinine, three-vessel disease, previous AMI and QRS and QT duration. During a mean follow-up of 1.3 years (range 0.4-2.3),109 patients (7.9%) died; 25, 45, and 39 from cardiac arrhythmia, nonarrhythmic cardiac causes and other causes, respectively. Long Tp-e was strongly associated with increased risk of death, and Tp-e remained a significant predictor of death in multivariable Cox analyses (RR 1.5, 95% CI[1.3-1.7]). HR-corrected Tp-e (cTp-e) was the strongest predictor of death (RR 1.6 [1.4-1.9]). Tp-e and cTp-e were particularly strong predictors of fatal cardiac arrhythmia (RR 1.6 [1.2-2.1] and RR 1.8 [1.4-2.4]). Findings were similar in STEMI and NSTEMI. When comparing two methods for measuring Tp-e, one including the tail of the T wave and one not, the former had markedly higher predictive power (P < 0.001). CONCLUSION Tp-e, and in particular cTp-e, were strong predictors of mortality during the first year post-AMI, and should be further evaluated as prognostic factors additional to established post-AMI risk factors.
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Affiliation(s)
- Gunnar Erikssen
- Department of Cardiology, Oslo University Hospital, Rikshospitalet, Norway.
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Lin YK, Chen YC, Chen JH, Chen SA, Chen YJ. Adipocytes modulate the electrophysiology of atrial myocytes: implications in obesity-induced atrial fibrillation. Basic Res Cardiol 2012; 107:293. [DOI: 10.1007/s00395-012-0293-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 07/17/2012] [Accepted: 07/31/2012] [Indexed: 01/19/2023]
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George CH, Parthimos D, Silvester NC. A network-oriented perspective on cardiac calcium signaling. Am J Physiol Cell Physiol 2012; 303:C897-910. [PMID: 22843795 DOI: 10.1152/ajpcell.00388.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The normal contractile, electrical, and energetic function of the heart depends on the synchronization of biological oscillators and signal integrators that make up cellular signaling networks. In this review we interpret experimental data from molecular, cellular, and transgenic models of cardiac signaling behavior in the context of established concepts in cell network architecture and organization. Focusing on the cellular Ca(2+) handling machinery, we describe how the plasticity and adaptability of normal Ca(2+) signaling is dependent on dynamic network configurations that operate across a wide range of functional states. We consider how (mal)adaptive changes in signaling pathways restrict the dynamic range of the network such that it cannot respond appropriately to physiologic stimuli or perturbation. Based on these concepts, a model is proposed in which pathologic abnormalities in cardiac rhythm and contractility (e.g., arrhythmias and heart failure) arise as a consequence of progressive desynchronization and reduction in the dynamic range of the Ca(2+) signaling network. We discuss how a systems-level understanding of the network organization, cellular noise, and chaotic behavior may inform the design of new therapeutic modalities that prevent or reverse the disease-linked unraveling of the Ca(2+) signaling network.
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Affiliation(s)
- Christopher H George
- Wales Heart Research Institute and Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff Univ., Heath Park, Cardiff, Wales, UK CF14 4XN.
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Dynamics of early afterdepolarization-mediated triggered activity in cardiac monolayers. Biophys J 2012; 102:2706-14. [PMID: 22735520 DOI: 10.1016/j.bpj.2012.05.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 04/22/2012] [Accepted: 05/08/2012] [Indexed: 11/20/2022] Open
Abstract
Early afterdepolarizations (EADs) are voltage oscillations that occur during the repolarizing phase of the cardiac action potential and cause cardiac arrhythmias in a variety of clinical settings. EADs occur in the setting of reduced repolarization reserve and increased inward-over-outward currents, which intuitively explains the repolarization delay but does not mechanistically explain the time-dependent voltage oscillations that are characteristic of EADs. In a recent theoretical study, we identified a dual Hopf-homoclinic bifurcation as a dynamical mechanism that causes voltage oscillations during EADs, depending on the amplitude and kinetics of the L-type Ca(2+) channel (LTCC) current relative to the repolarizing K(+) currents. Here we demonstrate this mechanism experimentally. We show that cardiac monolayers exposed to the LTCC agonists BayK8644 and isoproterenol produce EAD bursts that are suppressed by the LTCC blocker nitrendipine but not by the Na(+) current blocker tetrodoxin, depletion of intracellular Ca(2+) stores with thapsigargin and caffeine, or buffering of intracellular Ca(2+) with BAPTA-AM. These EAD bursts exhibited a key dynamical signature of the dual Hopf-homoclinic bifurcation mechanism, namely, a gradual slowing in the frequency of oscillations before burst termination. A detailed cardiac action potential model reproduced the experimental observations, and identified intracellular Na(+) accumulation as the likely mechanism for terminating EAD bursts. Our findings in cardiac monolayers provide direct support for the Hopf-homoclinic bifurcation mechanism of EAD-mediated triggered activity, and raise the possibility that this mechanism may also contribute to EAD formation in clinical settings such as long QT syndromes, heart failure, and increased sympathetic output.
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