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Liang D, Zhou L, Zhou H, Zhang F, Fang G, Leng J, Wu Y, Zhang Y, Yang A, Liu Y, Chen YH. A GABAergic system in atrioventricular node pacemaker cells controls electrical conduction between the atria and ventricles. Cell Res 2024; 34:556-571. [PMID: 38849501 PMCID: PMC11291642 DOI: 10.1038/s41422-024-00980-x] [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: 12/28/2023] [Accepted: 05/13/2024] [Indexed: 06/09/2024] Open
Abstract
Physiologically, the atria contract first, followed by the ventricles, which is the prerequisite for normal blood circulation. The above phenomenon of atrioventricular sequential contraction results from the characteristically slow conduction of electrical excitation of the atrioventricular node (AVN) between the atria and the ventricles. However, it is not clear what controls the conduction of electrical excitation within AVNs. Here, we find that AVN pacemaker cells (AVNPCs) possess an intact intrinsic GABAergic system, which plays a key role in electrical conduction from the atria to the ventricles. First, along with the discovery of abundant GABA-containing vesicles under the surface membranes of AVNPCs, key elements of the GABAergic system, including GABA metabolic enzymes, GABA receptors, and GABA transporters, were identified in AVNPCs. Second, GABA synchronously elicited GABA-gated currents in AVNPCs, which significantly weakened the excitability of AVNPCs. Third, the key molecular elements of the GABAergic system markedly modulated the conductivity of electrical excitation in the AVN. Fourth, GABAA receptor deficiency in AVNPCs accelerated atrioventricular conduction, which impaired the AVN's protective potential against rapid ventricular frequency responses, increased susceptibility to lethal ventricular arrhythmias, and decreased the cardiac contractile function. Finally, interventions targeting the GABAergic system effectively prevented the occurrence and development of atrioventricular block. In summary, the endogenous GABAergic system in AVNPCs determines the slow conduction of electrical excitation within AVNs, thereby ensuring sequential atrioventricular contraction. The endogenous GABAergic system shows promise as a novel intervention target for cardiac arrhythmias.
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Affiliation(s)
- Dandan Liang
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Research Units of Origin and Regulation of Heart Rhythm, Chinese Academy of Medical Sciences, Shanghai, China
- Clinical Center for Heart Disease Research, Tongji University, Shanghai, China
| | - Liping Zhou
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Huixing Zhou
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Fulei Zhang
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Guojian Fang
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Junwei Leng
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yahan Wu
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yuemei Zhang
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Anqi Yang
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yi Liu
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yi-Han Chen
- State Key Laboratory of Cardiovascular Diseases, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China.
- Shanghai Arrhythmia Research Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China.
- Department of Cardiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China.
- Research Units of Origin and Regulation of Heart Rhythm, Chinese Academy of Medical Sciences, Shanghai, China.
- Clinical Center for Heart Disease Research, Tongji University, Shanghai, China.
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Georgescu T. The role of maternal hormones in regulating autonomic functions during pregnancy. J Neuroendocrinol 2023; 35:e13348. [PMID: 37936545 DOI: 10.1111/jne.13348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 11/09/2023]
Abstract
Offspring development relies on numerous physiological changes that occur in a mother's body, with hormones driving many of these adaptations. Amongst these, the physiological functions controlled by the autonomic nervous system are required for the mother to survive and are adjusted to meet the demands of the growing foetus and to ensure a successful birth. The hormones oestrogen, progesterone, and lactogenic hormones rise significantly during pregnancy, suggesting they may also play a role in regulating the maternal adaptations linked to autonomic nervous system functions, including respiratory, cardiovascular, and thermoregulatory functions. Indeed, expression of pregnancy hormone receptors spans multiple brain regions known to regulate these physiological functions. This review examines how respiratory, cardiovascular, and thermoregulatory functions are controlled by these pregnancy hormones by focusing on their action on central nervous system circuits. Inadequate adaptations in these systems during pregnancy can give rise to several pregnancy complications, highlighting the importance in understanding the mechanistic underpinnings of these changes and potentially identifying ways to treat pregnancy-associated afflictions using hormones.
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Affiliation(s)
- T Georgescu
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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3
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Fan W, Sun X, Yang C, Wan J, Luo H, Liao B. Pacemaker activity and ion channels in the sinoatrial node cells: MicroRNAs and arrhythmia. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 177:151-167. [PMID: 36450332 DOI: 10.1016/j.pbiomolbio.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/13/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022]
Abstract
The primary pacemaking activity of the heart is determined by a spontaneous action potential (AP) within sinoatrial node (SAN) cells. This unique AP generation relies on two mechanisms: membrane clocks and calcium clocks. Nonhomologous arrhythmias are caused by several functional and structural changes in the myocardium. MicroRNAs (miRNAs) are essential regulators of gene expression in cardiomyocytes. These miRNAs play a vital role in regulating the stability of cardiac conduction and in the remodeling process that leads to arrhythmias. Although it remains unclear how miRNAs regulate the expression and function of ion channels in the heart, these regulatory mechanisms may support the development of emerging therapies. This study discusses the spread and generation of AP in the SAN as well as the regulation of miRNAs and individual ion channels. Arrhythmogenicity studies on ion channels will provide a research basis for miRNA modulation as a new therapeutic target.
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Affiliation(s)
- Wei Fan
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China
| | - Xuemei Sun
- Department of Pharmacy, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China
| | - Chao Yang
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China
| | - Juyi Wan
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China.
| | - Hongli Luo
- Department of Pharmacy, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China.
| | - Bin Liao
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China.
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Mayuga KA, Fedorowski A, Ricci F, Gopinathannair R, Dukes JW, Gibbons C, Hanna P, Sorajja D, Chung M, Benditt D, Sheldon R, Ayache MB, AbouAssi H, Shivkumar K, Grubb BP, Hamdan MH, Stavrakis S, Singh T, Goldberger JJ, Muldowney JAS, Belham M, Kem DC, Akin C, Bruce BK, Zahka NE, Fu Q, Van Iterson EH, Raj SR, Fouad-Tarazi F, Goldstein DS, Stewart J, Olshansky B. Sinus Tachycardia: a Multidisciplinary Expert Focused Review. Circ Arrhythm Electrophysiol 2022; 15:e007960. [PMID: 36074973 PMCID: PMC9523592 DOI: 10.1161/circep.121.007960] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Sinus tachycardia (ST) is ubiquitous, but its presence outside of normal physiological triggers in otherwise healthy individuals remains a commonly encountered phenomenon in medical practice. In many cases, ST can be readily explained by a current medical condition that precipitates an increase in the sinus rate, but ST at rest without physiological triggers may also represent a spectrum of normal. In other cases, ST may not have an easily explainable cause but may represent serious underlying pathology and can be associated with intolerable symptoms. The classification of ST, consideration of possible etiologies, as well as the decisions of when and how to intervene can be difficult. ST can be classified as secondary to a specific, usually treatable, medical condition (eg, pulmonary embolism, anemia, infection, or hyperthyroidism) or be related to several incompletely defined conditions (eg, inappropriate ST, postural tachycardia syndrome, mast cell disorder, or post-COVID syndrome). While cardiologists and cardiac electrophysiologists often evaluate patients with symptoms associated with persistent or paroxysmal ST, an optimal approach remains uncertain. Due to the many possible conditions associated with ST, and an overlap in medical specialists who see these patients, the inclusion of experts in different fields is essential for a more comprehensive understanding. This article is unique in that it was composed by international experts in Neurology, Psychology, Autonomic Medicine, Allergy and Immunology, Exercise Physiology, Pulmonology and Critical Care Medicine, Endocrinology, Cardiology, and Cardiac Electrophysiology in the hope that it will facilitate a more complete understanding and thereby result in the better care of patients with ST.
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Affiliation(s)
- Kenneth A. Mayuga
- Section of Cardiac Electrophysiology and Pacing, Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, OH
| | - Artur Fedorowski
- Karolinska Institutet & Karolinska University Hospital, Stockholm, Sweden
| | - Fabrizio Ricci
- Department of Neuroscience, Imaging and Clinical Sciences, “G.d’Annunzio” University of Chieti-Pescara, Chieti Scalo, Italy
| | | | | | | | | | | | - Mina Chung
- Section of Cardiac Electrophysiology and Pacing, Department of Cardiovascular Medicine, Cleveland Clinic, Phoenix, AZ
| | - David Benditt
- University of Minnesota Medical School, Minneapolis, MN
| | | | - Mirna B. Ayache
- MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH
| | - Hiba AbouAssi
- Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC
| | | | | | | | | | - Tamanna Singh
- Department of Cardiovascular Medicine, Cleveland Clinic, OH
| | | | - James A. S. Muldowney
- Vanderbilt University Medical Center &Tennessee Valley Healthcare System, Nashville Campus, Department of Veterans Affairs, Nashville, TN
| | - Mark Belham
- Cambridge University Hospitals NHS FT, Cambridge, UK
| | - David C. Kem
- University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Cem Akin
- University of Michigan, Ann Arbor, MI
| | | | - Nicole E. Zahka
- Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Qi Fu
- Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital Dallas & University of Texas Southwestern Medical Center, Dallas, TX
| | - Erik H. Van Iterson
- Section of Preventive Cardiology & Rehabilitation, Robert and Suzanne Tomsich Department of Cardiovascular Medicine, Miller Family Heart, Vascular & Thoracic Institute, Cleveland Clinic Cleveland, OH
| | - Satish R Raj
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
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Gajda R, Knechtle B, Gębska-Kuczerowska A, Gajda J, Stec S, Krych M, Kwaśniewska M, Drygas W. Amateur Athlete with Sinus Arrest and Severe Bradycardia Diagnosed through a Heart Rate Monitor: A Six-Year Observation-The Necessity of Shared Decision-Making in Heart Rhythm Therapy Management. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph191610367. [PMID: 36012002 PMCID: PMC9408438 DOI: 10.3390/ijerph191610367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 08/11/2022] [Accepted: 08/17/2022] [Indexed: 05/14/2023]
Abstract
Heart rate monitors (HRMs) are used by millions of athletes worldwide to monitor exercise intensity and heart rate (HR) during training. This case report presents a 34-year-old male amateur soccer player with severe bradycardia who accidentally identified numerous pauses of over 4 s (maximum length: 7.3 s) during sleep on his own HRM with a heart rate variability (HRV) function. Simultaneous HRM and Holter ECG recordings were performed in an outpatient clinic, finding consistent 6.3 s sinus arrests (SA) with bradycardia of 33 beats/min. During the patient's hospitalization for a transient ischemic attack, the longest pauses on the Holter ECG were recorded, and he was suggested to undergo pacemaker implantation. He then reduced the volume/intensity of exercise for 4 years. Afterward, he spent 2 years without any regular training due to depression. After these 6 years, another Holter ECG test was performed in our center, not confirming the aforementioned disturbances and showing a tendency to tachycardia. The significant SA was resolved after a period of detraining. The case indicates that considering invasive therapy was unreasonable, and patient-centered care and shared decision-making play a key role in cardiac pacing therapy. In addition, some sports HRM with an HRV function can help diagnose bradyarrhythmia, both in professional and amateur athletes.
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Affiliation(s)
- Robert Gajda
- Center for Sports Cardiology, Gajda-Med Medical Center, ul. Piotra Skargi 23/29, 06-100 Pułtusk, Poland
- Department of Kinesiology and Health Prevention, Jan Dlugosz University, 42-200 Czestochowa, Poland
- Correspondence: ; Tel.: +48-604286030
| | - Beat Knechtle
- Institute of Primary Care, University of Zurich, 8091 Zurich, Switzerland
- Medbase St. Gallen Am Vadianplatz, 9000 St. Gallen, Switzerland
| | - Anita Gębska-Kuczerowska
- Faculty of Medicine, Collegium Medicum, Cardinal Stefan Wyszyński University, Kazimierza Wóycickiego 1/3, 01-938 Warsaw, Poland
| | - Jacek Gajda
- Center for Sports Cardiology, Gajda-Med Medical Center, ul. Piotra Skargi 23/29, 06-100 Pułtusk, Poland
| | - Sebastian Stec
- Division of Electrophysiology, Cardioneuroablation, Catheter Ablation and Cardiac Stimulation, Subcarpathian Center for Cardiovascular Intervention, 38-500 Sanok, Poland
| | - Michalina Krych
- Department of Congenital Heart Diseases, The Cardinal Stefan Wyszyński National Institute of Cardiology, ul. Alpejska 42, 04-628 Warsaw, Poland
| | - Magdalena Kwaśniewska
- Department of Preventive Medicine, Faculty of Health, Medical University of Lodz, ul. Lucjana Żeligowskiego 7/9, 90-752 Łódź, Poland
| | - Wojciech Drygas
- Department of Congenital Heart Diseases, The Cardinal Stefan Wyszyński National Institute of Cardiology, ul. Alpejska 42, 04-628 Warsaw, Poland
- Department of Preventive Medicine, Faculty of Health, Medical University of Lodz, ul. Lucjana Żeligowskiego 7/9, 90-752 Łódź, Poland
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Abstract
Cardiovascular complications of pregnancy have risen substantially over the past decades, and now account for the majority of pregnancy-induced maternal deaths, as well as having substantial long-term consequences on maternal cardiovascular health. The causes and pathophysiology of these complications remain poorly understood, and therapeutic options are limited. Preclinical models represent a crucial tool for understanding human disease. We review here advances made in preclinical models of cardiovascular complications of pregnancy, including preeclampsia and peripartum cardiomyopathy, with a focus on pathological mechanisms elicited by the models and on relevance to human disease.
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Affiliation(s)
- Zolt Arany
- Department of Medicine and Cardiovascular Institute, University of Pennsylvania, Philadelphia (Z.A.)
| | - Denise Hilfiker-Kleiner
- Institute of Cardiovascular Complications in Pregnancy and in Oncologic Therapies, Philipps University Marburg, Germany (D.H.-K.)
| | - S Ananth Karumanchi
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (S.A.K.)
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7
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Frequency-Dependent Properties of the Hyperpolarization-Activated Cation Current, I f, in Adult Mouse Heart Primary Pacemaker Myocytes. Int J Mol Sci 2022; 23:ijms23084299. [PMID: 35457119 PMCID: PMC9024942 DOI: 10.3390/ijms23084299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/05/2022] [Accepted: 04/11/2022] [Indexed: 02/04/2023] Open
Abstract
A number of distinct electrophysiological mechanisms that modulate the myogenic spontaneous pacemaker activity in the sinoatrial node (SAN) of the mammalian heart have been investigated extensively. There is agreement that several (3 or 4) different transmembrane ionic current changes (referred to as the voltage clock) are involved; and that the resulting net current interacts with direct and indirect effects of changes in intracellular Ca2+ (the calcium clock). However, significant uncertainties, and important knowledge gaps, remain concerning the functional roles in SAN spontaneous pacing of many of the individual ion channel- or exchanger-mediated transmembrane current changes. We report results from patch clamp studies and mathematical modeling of the hyperpolarization-activated current, If, in the generation/modulation of the diastolic depolarization, or pacemaker potential, produced by individual myocytes that were enzymatically isolated from the adult mouse sinoatrial node (SAN). Amphotericin-mediated patch microelectrode recordings at 35 °C were made under control conditions and in the presence of 5 or 10 nM isoproterenol (ISO). These sets of results were complemented and integrated with mathematical modeling of the current changes that take place in the range of membrane potentials (−70 to −50 mV), which corresponds to the ‘pacemaker depolarization’ in the adult mouse SAN. Our results reveal a very small, but functionally important, approximately steady-state or time-independent current generated by residual activation of If channels that are expressed in these pacemaker myocytes. Recordings of the pacemaker depolarization and action potential, combined with measurements of changes in If, and the well-known increases in the L-type Ca2+ current, ICaL, demonstrated that ICaL activation, is essential for myogenic pacing. Moreover, after being enhanced (approximately 3-fold) by 5 or 10 nM ISO, ICaL contributes significantly to the positive chronotropic effect. Our mathematical model has been developed in an attempt to better understand the underlying mechanisms for the pacemaker depolarization and action potential in adult mouse SAN myocytes. After being updated with our new experimental data describing If, our simulations reveal a novel functional component of If in adult mouse SAN. Computational work carried out with this model also confirms that in the presence of ISO the residual activation of If and opening of ICaL channels combine to generate a net current change during the slow diastolic depolarization phase that is essential for the observed accelerated pacemaking rate of these SAN myocytes.
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Sharp A, Patient C, Pickett J, Belham M. Pregnancy-related inappropriate sinus tachycardia: A cohort analysis of maternal and fetal outcomes. Obstet Med 2021; 14:230-234. [PMID: 34880936 DOI: 10.1177/1753495x21990196] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/30/2020] [Indexed: 11/15/2022] Open
Abstract
Background Little literature exists regarding the syndrome of inappropriate sinus tachycardia during pregnancy. We aimed to further understand the natural history of inappropriate sinus tachycardia in pregnancy, and to explore maternal and fetal outcomes. Methods A retrospective, observational cohort analysis of 19 pregnant women who presented with inappropriate sinus tachycardia. Results 42% attended the emergency department on more than one occasion with symptoms of inappropriate sinus tachycardia; 32% required hospital admission and 26% required pharmacological therapy. There were no maternal deaths, instances of heart failure or acute coronary syndrome, and no thromboembolic or haemorrhagic complications during pregnancy. Rates of caesarean section were similar to the background rate of our unit (32% and 27%, respectively). Rates of induction were notably elevated (58% vs 25%). Conclusion Inappropriate sinus tachycardia in pregnancy is associated with high rates of hospitalization and induction of labour, which may not be mandatory given the clinical findings in this group of women.
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Affiliation(s)
- Alexander Sharp
- Department of Cardiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Charlotte Patient
- Department of Obstetrics, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Janet Pickett
- Department of Anaesthesia, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Mark Belham
- Department of Cardiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
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Tonko JB, Douglas H, Wright MJ. Ivabradine-sensitive incessant atrial tachycardia during pregnancy: a case report. Eur Heart J Case Rep 2021; 5:ytab367. [PMID: 34632265 PMCID: PMC8497877 DOI: 10.1093/ehjcr/ytab367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/07/2021] [Accepted: 08/27/2021] [Indexed: 11/13/2022]
Abstract
Background Automaticity is the dominant mechanism in maternal focal atrial tachycardia (FAT) during pregnancy and if incessant, can cause tachycardia-induced cardiomyopathy. Medication failure for FATs is common, however, for the subgroup due to increased automaticity ivabradine sensitivity has been described and may represent a valuable treatment option. Little data are available regarding the safety profile of ivabradine during pregnancy. Case Summary We report the case of a 38-year-old woman with background of peripartum cardiomyopathy and incessant atrial tachycardia with deteriorating ventricular function during her second pregnancy unresponsive to betablockade and demonstrating the immediate successful rate-controlling effect of ivabradine. Discussion Early recognition of persistent maternal FAT is essential due to its frequent association with tachycardia-mediated cardiomyopathy. Our case report highlights the challenges of providing an equally safe and effective treatment of these notoriously difficult to treat arrhythmias during pregnancy. Ivabradine in combination with a betablocker can be effective for abnormal automaticity but its safety profile during pregnancy remains uncertain.
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Affiliation(s)
- Johanna B Tonko
- Department of Cardiology, St Thomas' Hospital, Westminster Bridge Rd, London SE1 7EH, UK
- Faculty of Life Sciences and Medicine, King's College London, Strand, London WC2R 2LS, UK
| | - Hannah Douglas
- Department of Cardiology, St Thomas' Hospital, Westminster Bridge Rd, London SE1 7EH, UK
- Faculty of Life Sciences and Medicine, King's College London, Strand, London WC2R 2LS, UK
| | - Matthew J Wright
- Department of Cardiology, St Thomas' Hospital, Westminster Bridge Rd, London SE1 7EH, UK
- Faculty of Life Sciences and Medicine, King's College London, Strand, London WC2R 2LS, UK
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Regulation of sinus node pacemaking and atrioventricular node conduction by HCN channels in health and disease. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:61-85. [PMID: 34197836 DOI: 10.1016/j.pbiomolbio.2021.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 06/02/2021] [Accepted: 06/14/2021] [Indexed: 12/19/2022]
Abstract
The funny current, If, was first recorded in the heart 40 or more years ago by Dario DiFrancesco and others. Since then, we have learnt that If plays an important role in pacemaking in the sinus node, the innate pacemaker of the heart, and more recently evidence has accumulated to show that If may play an important role in action potential conduction through the atrioventricular (AV) node. Evidence has also accumulated to show that regulation of the transcription and translation of the underlying Hcn genes plays an important role in the regulation of sinus node pacemaking and AV node conduction under normal physiological conditions - in athletes, during the circadian rhythm, in pregnancy, and during postnatal development - as well as pathological states - ageing, heart failure, pulmonary hypertension, diabetes and atrial fibrillation. There may be yet more pathological conditions involving changes in the expression of the Hcn genes. Here, we review the role of If and the underlying HCN channels in physiological and pathological changes of the sinus and AV nodes and we begin to explore the signalling pathways (microRNAs, transcription factors, GIRK4, the autonomic nervous system and inflammation) involved in this regulation. This review is dedicated to Dario DiFrancesco on his retirement.
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11
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Fürniss HE, Stiller B. Arrhythmic risk during pregnancy in patients with congenital heart disease. Herzschrittmacherther Elektrophysiol 2021; 32:174-179. [PMID: 33796929 DOI: 10.1007/s00399-021-00754-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/16/2021] [Indexed: 11/30/2022]
Abstract
Arrhythmias play a significant role in the morbidity and mortality of patients with adult congenital heart disease (CHD). Pregnancy-associated physiological changes in hormonal status, hemodynamics, and myocardial structure further enhance arrhythmic risk in CHD patients, leading to increased adverse maternal and foetal events and making arrhythmias one of the most common complications during pregnancy. Nearly all CHD patients are affected by asymptomatic rhythm disturbances during the ante-, peri-, or post-partum periods, and almost one tenth of patients develop sustained, symptomatic arrhythmias requiring treatment. The majority of arrhythmias originate from the atrium, mostly in the form of supraventricular tachycardia or atrial fibrillation. Patients with CHD often tolerate these even more poorly during pregnancy than before pregnancy. Sustained ventricular tachycardia or ventricular fibrillation are rare, but potentially life-threatening for mother and foetus. Risk stratification models developed specifically for arrhythmias during pregnancy in CHD patients are lacking, but direct or indirect signs of heart failure, previous history of arrhythmia, and complex CHD may be associated with higher arrhythmic risk in these patients. Rigorous individual assessment before, and careful monitoring during pregnancy in a multidisciplinary team is crucial to ensure the best possible pregnancy outcome for patients with CHD.
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Affiliation(s)
- Hannah E Fürniss
- Department of Congenital Heart Disease and Pediatric Cardiology, University Heart Center Freiburg-Bad Krozingen, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany.
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany.
| | - Brigitte Stiller
- Department of Congenital Heart Disease and Pediatric Cardiology, University Heart Center Freiburg-Bad Krozingen, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany
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12
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Long V, Mathieu S, Fiset C. Pregnancy-induced increased heart rate is independent of thyroid hormones. Heart Rhythm O2 2021; 2:168-173. [PMID: 34113919 PMCID: PMC8183852 DOI: 10.1016/j.hroo.2021.03.001] [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: 11/29/2022] Open
Abstract
Background The heart rate increases by 10–20 beats per minute (bpm) throughout pregnancy in women, reaching maximum heart rate in the third trimester. During pregnancy, important changes in thyroid hormones also occur, with increases of up to 50% in the levels of triiodothyronine (T3), the biological active thyroid hormone. In addition, T3 has been shown to regulate cardiac electrophysiology. Objective Thus, in the present study the potential contribution of T3 in pregnancy-induced increased heart rate was explored. Methods We compared the heart rate between nonpregnant and pregnant mice under control conditions and after altering thyroid hormone levels with T3 and propylthiouracil (PTU, an antithyroid drug) treatments. Results Consistent with the clinical data, we found a 58% rise in T3 levels during pregnancy in mice. Although pregnant mice had a higher baseline heart rate (607 ± 8 bpm, P = .004) and higher T3 levels (1.9 ± 0.4 nM, P = .0005) than nonpregnant mice (heart rate: 546 ± 16 bpm; T3 levels: 1.2 ± 0.1 nM), their heart rate responded similarly to T3 treatment as nonpregnant mice (nonpregnant: Δ130 ± 22 bpm; pregnant: Δ126 ± 17 bpm, P = .858). Additionally, the heart rate remained significantly elevated (607 ± 11 bpm, P = .038) and comparable to untreated pregnant mice, after the use of the antithyroid drug PTU, although T3 levels (1.3 ± 0.2 nM, P = .559) returned to nonpregnant values. Conclusion Based on these results, it is unlikely that T3 contributes significantly to the pregnancy-induced increased heart rate.
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Affiliation(s)
- Valérie Long
- Research Center, Montreal Heart Institute, Montreal, Canada.,Faculty of Pharmacy, Université de Montréal, Montreal, Canada
| | - Sophie Mathieu
- Research Center, Montreal Heart Institute, Montreal, Canada.,Faculty of Pharmacy, Université de Montréal, Montreal, Canada
| | - Céline Fiset
- Research Center, Montreal Heart Institute, Montreal, Canada.,Faculty of Pharmacy, Université de Montréal, Montreal, Canada
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13
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RNAseq shows an all-pervasive day-night rhythm in the transcriptome of the pacemaker of the heart. Sci Rep 2021; 11:3565. [PMID: 33574422 PMCID: PMC7878777 DOI: 10.1038/s41598-021-82202-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 01/01/2021] [Indexed: 12/12/2022] Open
Abstract
Physiological systems vary in a day-night manner anticipating increased demand at a particular time. Heart is no exception. Cardiac output is primarily determined by heart rate and unsurprisingly this varies in a day-night manner and is higher during the day in the human (anticipating increased day-time demand). Although this is attributed to a day-night rhythm in post-translational ion channel regulation in the heart's pacemaker, the sinus node, by the autonomic nervous system, we investigated whether there is a day-night rhythm in transcription. RNAseq revealed that ~ 44% of the sinus node transcriptome (7134 of 16,387 transcripts) has a significant day-night rhythm. The data revealed the oscillating components of an intrinsic circadian clock. Presumably this clock (or perhaps the master circadian clock in the suprachiasmatic nucleus) is responsible for the rhythm observed in the transcriptional machinery, which in turn is responsible for the rhythm observed in the transcriptome. For example, there is a rhythm in transcripts responsible for the two principal pacemaker mechanisms (membrane and Ca2+ clocks), transcripts responsible for receptors and signalling pathways known to control pacemaking, transcripts from genes identified by GWAS as determinants of resting heart rate, and transcripts from genes responsible for familial and acquired sick sinus syndrome.
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14
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Ruiz M, Khairallah M, Dingar D, Vaniotis G, Khairallah RJ, Lauzier B, Thibault S, Trépanier J, Shi Y, Douillette A, Hussein B, Nawaito SA, Sahadevan P, Nguyen A, Sahmi F, Gillis MA, Sirois MG, Gaestel M, Stanley WC, Fiset C, Tardif JC, Allen BG. MK2-Deficient Mice Are Bradycardic and Display Delayed Hypertrophic Remodeling in Response to a Chronic Increase in Afterload. J Am Heart Assoc 2021; 10:e017791. [PMID: 33533257 PMCID: PMC7955338 DOI: 10.1161/jaha.120.017791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Background Mitogen‐activated protein kinase–activated protein kinase‐2 (MK2) is a protein serine/threonine kinase activated by p38α/β. Herein, we examine the cardiac phenotype of pan MK2‐null (MK2−/−) mice. Methods and Results Survival curves for male MK2+/+ and MK2−/− mice did not differ (Mantel‐Cox test, P=0.580). At 12 weeks of age, MK2−/− mice exhibited normal systolic function along with signs of possible early diastolic dysfunction; however, aging was not associated with an abnormal reduction in diastolic function. Both R‐R interval and P‐R segment durations were prolonged in MK2‐deficient mice. However, heart rates normalized when isolated hearts were perfused ex vivo in working mode. Ca2+ transients evoked by field stimulation or caffeine were similar in ventricular myocytes from MK2+/+ and MK2−/− mice. MK2−/− mice had lower body temperature and an age‐dependent reduction in body weight. mRNA levels of key metabolic genes, including Ppargc1a, Acadm, Lipe, and Ucp3, were increased in hearts from MK2−/− mice. For equivalent respiration rates, mitochondria from MK2−/− hearts showed a significant decrease in Ca2+ sensitivity to mitochondrial permeability transition pore opening. Eight weeks of pressure overload increased left ventricular mass in MK2+/+ and MK2−/− mice; however, after 2 weeks the increase was significant in MK2+/+ but not MK2−/− mice. Finally, the pressure overload–induced decrease in systolic function was attenuated in MK2−/− mice 2 weeks, but not 8 weeks, after constriction of the transverse aorta. Conclusions Collectively, these results implicate MK2 in (1) autonomic regulation of heart rate, (2) cardiac mitochondrial function, and (3) the early stages of myocardial remodeling in response to chronic pressure overload.
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Affiliation(s)
- Matthieu Ruiz
- Department of Medicine Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | - Maya Khairallah
- Department of Biochemistry and Molecular Medicine Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | - Dharmendra Dingar
- Department of Biochemistry and Molecular Medicine Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | - George Vaniotis
- Department of Biochemistry and Molecular Medicine Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | | | | | - Simon Thibault
- Faculté de Pharmacie Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | - Joëlle Trépanier
- Department of Biochemistry and Molecular Medicine Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | - Yanfen Shi
- Montreal Heart Institute Montréal Québec Canada
| | | | | | - Sherin Ali Nawaito
- Department of Pharmacology and Physiology Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada.,Department of Physiology Faculty of Medicine Suez Canal University Ismailia Egypt
| | - Pramod Sahadevan
- Department of Biochemistry and Molecular Medicine Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | - Albert Nguyen
- Department of Pharmacology and Physiology Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | | | | | - Martin G Sirois
- Department of Pharmacology and Physiology Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | - Matthias Gaestel
- Institute of Cell BiochemistryHannover Medical School Hannover Germany
| | | | - Céline Fiset
- Faculté de Pharmacie Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | - Jean-Claude Tardif
- Department of Medicine Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
| | - Bruce G Allen
- Department of Medicine Université de Montréal Québec Canada.,Department of Biochemistry and Molecular Medicine Université de Montréal Québec Canada.,Department of Pharmacology and Physiology Université de Montréal Québec Canada.,Montreal Heart Institute Montréal Québec Canada
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15
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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16
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Wang NC, Shen C, McLaughlin TJ, Li JZ, Hauspurg A, Berlacher KL, Bhonsale A, Jain SK, Kancharla K, Saba S. Maternal focal atrial tachycardia during pregnancy: A systematic review. J Cardiovasc Electrophysiol 2020; 31:2982-2997. [PMID: 32897619 DOI: 10.1111/jce.14738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/19/2020] [Accepted: 08/25/2020] [Indexed: 01/08/2023]
Abstract
INTRODUCTION The presentation and optimal management of maternal focal atrial tachycardia (AT) during pregnancy are unknown. The objective of this study is to conduct a comprehensive summary of the existing evidence. METHODS AND RESULTS A systematic review of all reported cases of maternal focal AT during pregnancy was performed. The primary search queried PubMed using the MeSH terms "supraventricular tachycardia" and "pregnancy." A stepwise ancillary search included article bibliographies, citations listed by the Google internet search engine, and PubMed using the MeSH terms "atrial tachycardia" and "pregnancy." In total, 28 citations that described 32 patients were retrieved. A case from our institution was added. Detailed information was available for 30 patients. Clinical characteristics at presentation included a mean ± standard deviation of 28.3 ± 5.7 years for maternal age and 24.6 ± 7.7 weeks for gestation age. Suspected tachycardia-induced cardiomyopathy was present in 20 of 30 (67%) patients and left ventricular ejection fraction improved in 15 of 15 (100%) patients with follow-up measurements. Medication failure was common. Focal AT resolved spontaneously after delivery in eight of nine (89%) patients treated with only medications. Automaticity was suggested by discrete electrograms at sites of origin and lack of reported inducibility and termination with programmed stimulation in all patients who underwent electrophysiology studies. There were nine cases of successful catheter ablation with zero fluoroscopy since 2010. CONCLUSIONS Automaticity is the dominant mechanism for patients with maternal focal AT during pregnancy. Catheter ablation with zero fluoroscopy is an emerging therapy for medically refractory cases.
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Affiliation(s)
- Norman C Wang
- Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Carlita Shen
- Department of Internal Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Terence J McLaughlin
- Department of Internal Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jack Z Li
- Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Alisse Hauspurg
- Department of Obstetrics, Gynecology, and Reproductive Services, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Kathryn L Berlacher
- Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Aditya Bhonsale
- Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Sandeep K Jain
- Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Krishna Kancharla
- Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Samir Saba
- Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
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17
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Long V, Fiset C. Contribution of estrogen to the pregnancy-induced increase in cardiac automaticity. J Mol Cell Cardiol 2020; 147:27-34. [PMID: 32798536 DOI: 10.1016/j.yjmcc.2020.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/21/2020] [Accepted: 08/06/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND The heart rate progressively increases throughout pregnancy, reaching a maximum in the third trimester. This elevated heart rate is also present in pregnant mice and is associated with accelerated automaticity, higher density of the pacemaker current If and changes in Ca2+ homeostasis in sinoatrial node (SAN) cells. Strong evidence has also been provided showing that 17β-estradiol (E2) and estrogen receptor α (ERα) regulate heart rate. Accordingly, we sought to determine whether E2 levels found in late pregnancy cause the increased cardiac automaticity associated with pregnancy. METHODS AND RESULTS Voltage- and current-clamp experiments were carried out on SAN cells isolated from female mice lacking estrogen receptor alpha (ERKOα) or beta (ERKOβ) receiving chronic E2 treatment mimicking late pregnancy concentrations. E2 treatment significantly increased the action potential rate (284 ± 24 bpm, +E2 354 ± 23 bpm, p = 0.040) and the density of If (+52%) in SAN cells from ERKOβ mice. However, If density remains unchanged in SAN cells from E2-treated ERKOα mice. Additionally, E2 also increased If density (+67%) in nodal-like human-induced pluripotent stem cell-derived cardiomyocytes (N-hiPSC-CM), recapitulating in a human SAN cell model the effect produced in mice. However, the L-type calcium current (ICaL) and Ca2+ transients, examined using N-hiPSC-CM and SAN cells respectively, were not affected by E2, indicating that other mechanisms contribute to changes observed in these parameters during pregnancy. CONCLUSION The accelerated SAN automaticity observed in E2-treated ERKOβ mice is explained by an increased If density mediated by ERα, demonstrating that E2 plays a major role in regulating SAN function during pregnancy.
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Affiliation(s)
- Valérie Long
- Research Center, Montreal Heart Institute, 5000 Bélanger, Montréal H1T 1C8, Québec, Canada; Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada.
| | - Céline Fiset
- Research Center, Montreal Heart Institute, 5000 Bélanger, Montréal H1T 1C8, Québec, Canada; Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada.
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18
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Liang W, Han P, Kim EH, Mak J, Zhang R, Torrente AG, Goldhaber JI, Marbán E, Cho HC. Canonical Wnt signaling promotes pacemaker cell specification of cardiac mesodermal cells derived from mouse and human embryonic stem cells. Stem Cells 2019; 38:352-368. [PMID: 31648393 DOI: 10.1002/stem.3106] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 08/30/2019] [Indexed: 01/03/2023]
Abstract
Cardiac differentiation of embryonic stem cells (ESCs) can give rise to de novo chamber cardiomyocytes and nodal pacemaker cells. Compared with our understanding of direct differentiation toward atrial and ventricular myocytes, the mechanisms for nodal pacemaker cell commitment are not well understood. Taking a cue from the prominence of canonical Wnt signaling during cardiac pacemaker tissue development in chick embryos, we asked if modulations of Wnt signaling influence cardiac progenitors to bifurcate to either chamber cardiomyocytes or pacemaker cells. Omitting an exogenous Wnt inhibitor, which is routinely added to maximize cardiac myocyte yield during differentiation of mouse and human ESCs, led to increased yield of spontaneously beating cardiomyocytes with action potential properties similar to those of native sinoatrial node pacemaker cells. The pacemaker phenotype was accompanied by enhanced expression of genes and gene products that mark nodal pacemaker cells such as Hcn4, Tbx18, Tbx3, and Shox2. Addition of exogenous Wnt3a ligand, which activates canonical Wnt/β-catenin signaling, increased the yield of pacemaker-like myocytes while reducing cTNT-positive pan-cardiac differentiation. Conversely, addition of inhibitors of Wnt/β-catenin signaling led to increased chamber myocyte lineage development at the expense of pacemaker cell specification. The positive impact of canonical Wnt signaling on nodal pacemaker cell differentiation was evidenced in direct differentiation of two human ESC lines and human induced pluripotent stem cells. Our data identify the Wnt/β-catenin pathway as a critical determinant of cardiac myocyte subtype commitment during ESC differentiation: endogenous Wnt signaling favors the pacemaker lineage, whereas its suppression promotes the chamber cardiomyocyte lineage.
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Affiliation(s)
- Wenbin Liang
- University of Ottawa Heart Institute and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Pengcheng Han
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Elizabeth H Kim
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Jordan Mak
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Rui Zhang
- Cedars-Sinai Heart Institute, Los Angeles, California
| | | | | | | | - Hee Cheol Cho
- Department of Pediatrics, Emory University, Atlanta, Georgia.,Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
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19
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El Khoury N, Ross JL, Long V, Thibault S, Ethier N, Fiset C. Pregnancy and oestrogen regulate sinoatrial node calcium homeostasis and accelerate pacemaking. Cardiovasc Res 2019; 114:1605-1616. [PMID: 29800268 PMCID: PMC6148331 DOI: 10.1093/cvr/cvy129] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 05/17/2018] [Indexed: 12/24/2022] Open
Abstract
Aims During pregnancy, there is a significant increase in heart rate (HR) potentially associated with an increased risk of arrhythmias or exacerbation of pre-existing cardiac conditions endangering both mother and foetus. Calcium homeostasis plays an important role in regulating automaticity of the sinoatrial node (SAN); however, its contribution to the accelerated HR during pregnancy remains unknown. Methods and results Using murine SAN cells, we showed that pregnancy increased L-type Ca2+ current (ICaL) and CaV1.3 mRNA expression, whereas T-type Ca2+ current (ICaT) and its underlying channel were unchanged. Analysis of SAN intra-cellular Ca2+ oscillations showed that the rate of spontaneous Ca2+ transients was significantly higher in pregnant mice along with a higher mRNA expression of ryanodine receptor. Assessment of supra-ventricular arrhythmias using programmed electrical stimulation protocols on anaesthetized mice revealed higher susceptibility in pregnancy. Of note, the modifications associated with pregnancy were reversible following delivery. Furthermore, chronic administration of 17β-estradiol (E2) to nodal-like human-induced pluripotent stem cell-derived cardiomyocytes (N-hiPSC-CM), control mice, oestrogen-receptor-β knockout (ERKOβ) but not ERKOα mice, accelerated cardiac automaticity, recapitulating the pregnancy phenotype in both mouse and human SAN cell models. Conclusion Together, these results indicate that pregnancy considerably alters intra-cellular Ca2+ homeostasis sustaining faster HR during pregnancy. Importantly, these changes were dependent on an oestrogen receptor α (ERα) mechanism that resulted in increased ICaL and spontaneous Ca2+ release from the sarcoplasmic reticulum, highlighting a novel role for oestrogen in regulating HR.
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Affiliation(s)
- Nabil El Khoury
- Montreal Heart Institute, Research Center, 5000 Bélanger, Montréal, Québec, Canada.,Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Jenna L Ross
- Montreal Heart Institute, Research Center, 5000 Bélanger, Montréal, Québec, Canada.,Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
| | - Valérie Long
- Montreal Heart Institute, Research Center, 5000 Bélanger, Montréal, Québec, Canada.,Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
| | - Simon Thibault
- Montreal Heart Institute, Research Center, 5000 Bélanger, Montréal, Québec, Canada.,Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
| | - Nathalie Ethier
- Montreal Heart Institute, Research Center, 5000 Bélanger, Montréal, Québec, Canada
| | - Céline Fiset
- Montreal Heart Institute, Research Center, 5000 Bélanger, Montréal, Québec, Canada.,Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
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20
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Abstract
It is established that an intensive training results in a lower average resting heart rate. Management of bradycardia in an athlete can be difficult given the underlying mechanisms are not clearly understood. The authors reviewed the different mechanisms described in the literature, including recent advances in physiology regarding remodeling of ion channels, which may partially explain bradycardia in athletes. Sinus bradycardia amongst athletes, especially endurance focused athletes, is common but difficult to apprehend. The underlying mechanisms are observably of multifactorial origin and likely incompletely elucidated by the current body of knowledge.
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Affiliation(s)
- Benoit Doyen
- Department of Cardiology, CHU UCL Namur , Yvoir , Belgium
| | - David Matelot
- Department of Cardiology, Hopital Pontchaillou , Rennes , France
| | - François Carré
- Department of Cardiology, Hopital Pontchaillou Service de medecine du sport , Rennes , France
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21
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Natriuretic Peptide Receptor-C Protects Against Angiotensin II-Mediated Sinoatrial Node Disease in Mice. JACC Basic Transl Sci 2018; 3:824-843. [PMID: 30623142 PMCID: PMC6314975 DOI: 10.1016/j.jacbts.2018.08.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 12/19/2022]
Abstract
SAN disease is prevalent in hypertension and heart failure and can be induced by chronic Ang II treatment in mice. Ang II caused SAN disease in mice in association with impaired electrical conduction, reduction in the hyperpolarization-activated current (If) in SAN myocytes, and increased SAN fibrosis. Ang II-induced SAN disease was worsened in mice lacking NPR-C in association with enhanced SAN fibrosis. Mice co-treated with Ang II and an NPR-C agonist (cANF) were protected from SAN disease. NPR-C may represent a new target to protect against Ang II-induced SAN disease.
Sinoatrial node (SAN) disease mechanisms are poorly understood, and therapeutic options are limited. Natriuretic peptide(s) (NP) are cardioprotective hormones whose effects can be mediated partly by the NP receptor C (NPR-C). We investigated the role of NPR-C in angiotensin II (Ang II)-mediated SAN disease in mice. Ang II caused SAN disease due to impaired electrical activity in SAN myocytes and increased SAN fibrosis. Strikingly, Ang II treatment in NPR-C−/− mice worsened SAN disease, whereas co-treatment of wild-type mice with Ang II and a selective NPR-C agonist (cANF) prevented SAN dysfunction. NPR-C may represent a new target to protect against the development of Ang II-induced SAN disease.
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Key Words
- AP, action potential
- Ang II, angiotensin II
- CV, conduction velocity
- DD, diastolic depolarization
- Gmax, maximum conductance
- HR, heart rate
- ICa,L, L-type calcium current
- ICa,T, T-type calcium current
- INCX, sodium–calcium exchanger current
- IV, current voltage relationship
- If, hyperpolarization-activated current
- NP, natriuretic peptide
- NPR, natriuretic peptide receptor
- NPR-C, natriuretic peptide receptor C
- SAN, sinoatrial node
- SBP, systolic blood pressure
- V1/2(act), voltage for 50% channel activation
- cSNRT, corrected sinoatrial node recovery time
- fibrosis
- hypertension
- ion currents
- natriuretic peptide
- sinoatrial node
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Choudhury M, Black N, Alghamdi A, D'Souza A, Wang R, Yanni J, Dobrzynski H, Kingston PA, Zhang H, Boyett MR, Morris GM. TBX18 overexpression enhances pacemaker function in a rat subsidiary atrial pacemaker model of sick sinus syndrome. J Physiol 2018; 596:6141-6155. [PMID: 30259525 PMCID: PMC6292813 DOI: 10.1113/jp276508] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 09/14/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The sinoatrial node (SAN) is the primary pacemaker of the heart. SAN dysfunction, or 'sick sinus syndrome', can cause excessively slow heart rates and pauses, leading to exercise limitation and syncope, currently treated by implantation of an electronic pacemaker. 'Biopacemaking' utilises gene therapy to restore pacemaker activity by manipulating gene expression. Overexpressing the HCN pacemaker ion channel has been widely used with limited success. We utilised bradycardic rat subsidiary atrial pacemaker tissue to evaluate alternative gene targets: the Na+ /Ca2+ exchanger NCX1, and the transcription factors TBX3 and TBX18 known to be involved in SAN embryonic development. TBX18 overexpression restored normal SAN function, as assessed by increased rate, improved heart rate stability and restoration of isoprenaline response. TBX3 and NCX1 were not effective in accelerating the rate of subsidiary atrial pacemaker tissue. Gene therapy targeting TBX18 could therefore have the potential to restore pacemaker function in human sick sinus syndrome obviating electronic pacemakers. ABSTRACT The sinoatrial node (SAN) is the primary pacemaker of the heart. Disease of the SAN, sick sinus syndrome, causes heart rate instability in the form of bradycardia and pauses, leading to exercise limitation and syncope. Biopacemaking aims to restore pacemaker activity by manipulating gene expression, and approaches utilising HCN channel overexpression have been widely used. We evaluated alternative gene targets for biopacemaking to restore normal SAN pacemaker physiology within bradycardic subsidiary atrial pacemaker (SAP) tissue, using the Na+ /Ca2+ exchanger NCX1, and the transcription factors TBX3 and TBX18. TBX18 expression in SAP tissue restored normal SAN function, as assessed by increased rate (SAN 267.5 ± 13.6 bpm, SAP 144.1 ± 8.6 bpm, SAP-TBX18 214.4 ± 14.4 bpm; P < 0.001), improved heart rate stability (standard deviation of RR intervals fell from 39.3 ± 7.2 ms to 6.9 ± 0.8 ms, P < 0.01; root mean square of successive differences of RR intervals fell from 41.7 ± 8.2 ms to 6.1 ± 1.2 ms, P < 0.01; standard deviation of points perpendicular to the line of identity of Poincaré plots (SD1) fell from 29.5 ± 5.8 ms to 7.9 ± 2.0 ms, P < 0.05) and restoration of isoprenaline response (increases in rates of SAN 65.5 ± 1.3%, SAP 28.4 ± 3.4% and SAP-TBX18 103.3 ± 10.2%; P < 0.001). These changes were driven by a TBX18-induced switch in the dominant HCN isoform in SAP tissue, with a significant upregulation of HCN2 (from 1.01 × 10-5 ± 2.2 × 10-6 to 2.8 × 10-5 ± 4.3 × 10-6 arbitrary units, P < 0.001). Biophysically detailed computer modelling incorporating isoform-specific HCN channel electrophysiology confirmed that the measured changes in HCN abundance could account for the observed changes in beating rates. TBX3 and NCX1 were not effective in accelerating the rate of SAP tissue.
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Affiliation(s)
- M. Choudhury
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - N. Black
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - A. Alghamdi
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - A. D'Souza
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - R. Wang
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - J. Yanni
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - H. Dobrzynski
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - P. A. Kingston
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - H. Zhang
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - M. R. Boyett
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
| | - G. M. Morris
- Institute of Cardiovascular SciencesUniversity of ManchesterManchesterUK
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Odening KE, Deiß S, Dilling-Boer D, Didenko M, Eriksson U, Nedios S, Ng FS, Roca Luque I, Sanchez Borque P, Vernooy K, Wijnmaalen AP, Yorgun H. Mechanisms of sex differences in atrial fibrillation: role of hormones and differences in electrophysiology, structure, function, and remodelling. Europace 2018; 21:366-376. [DOI: 10.1093/europace/euy215] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 09/03/2018] [Indexed: 12/28/2022] Open
Affiliation(s)
- Katja E Odening
- Department of Cardiology and Angiology I, Heart Center, University of Freiburg, Hugstetter Str. 55, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, HX Maastricht, The Netherlands
| | - Sebastian Deiß
- Asklepios Medical Center Altona, Department of Cardiology, Arrhythmia Unit, Hamburg, Germany
| | | | - Maxim Didenko
- Department of Surgical and Interventional Arrhythmology, Kuprianov's Cardiovascular Surgery Clinic, Military Medical Academy, St. Petersburg, Russia
| | - Urs Eriksson
- Rhythmology Division, Department of Medicine, GZO Regional Health Center, Wetzikon, Switzerland
- Cardioimmunology, Center for Molecular Cardiology, University of Zurich, Zurich-Schlieren, Switzerland
| | - Sotirios Nedios
- Heart Center, University of Leipzig, Leipzig, Germany
- Massachusetts General Hospital, Harvard University, Boston, MA, USA
| | - Fu Siong Ng
- National Heart & Lung Institute, Imperial College London, London, UK
| | - Ivo Roca Luque
- Arrhythmia Unit, Cardiology Department, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | | | - Kevin Vernooy
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, HX Maastricht, The Netherlands
- Department of Cardiology, Radboud University Medical Center, GA Nijmegen, The Netherlands
| | - Adrianus P Wijnmaalen
- Department of Cardiology, Leiden University Medical Center, ZA Leiden, The Netherlands
| | - Hikmet Yorgun
- Department of Cardiology, Electrophysiology Unit, Hacettepe University, Ankara, Turkey
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Kozasa Y, Nakashima N, Ito M, Ishikawa T, Kimoto H, Ushijima K, Makita N, Takano M. HCN4 pacemaker channels attenuate the parasympathetic response and stabilize the spontaneous firing of the sinoatrial node. J Physiol 2018; 596:809-825. [PMID: 29315578 PMCID: PMC5830425 DOI: 10.1113/jp275303] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 01/02/2018] [Indexed: 01/01/2023] Open
Abstract
Key points The contribution of HCN4 pacemaker channels in the autonomic regulation of the sino‐atrial node (SAN) has been a matter of debate. The transgenic overexpression of HCN4 did not induce tachycardia, but reduced heart rate variability, while the conditional knockdown of HCN4 gave rise to sinus arrhythmia. The response of the SAN to β‐adrenergic stimulation was not affected by overexpression or knockdown of HCN4 channels. When HCN4 channels were knocked down, the parasympathetic response examined by cervical vagus nerve stimulation (CVNS) was enhanced; the CVNS induced complete sinus pause. The overexpression of HCN4 attenuated bradycardia induced by CVNS only during β‐adrenergic stimulation. We concluded that HCN4 pacemaker channels stabilize the spontaneous firing by attenuating the parasympathetic response of the SAN.
Abstract The heart rate is dynamically controlled by the sympathetic and parasympathetic nervous systems that regulate the sinoatrial node (SAN). HCN4 pacemaker channels are the well‐known causative molecule of congenital sick sinus syndrome. Although HCN4 channels are activated by cAMP, the sympathetic response of the SAN was preserved in patients carrying loss‐of‐function mutations of the HCN4 gene. In order to clarify the contribution of HCN4 channels in the autonomic regulation of the SAN, we developed novel gain‐of‐function mutant mice in which the expression level of HCN4 channels could be reversibly changed from zero to ∼3 times that in wild‐type mice, using tetracycline transactivator and the tetracycline responsive element. We recorded telemetric ECGs in freely moving conscious mice and analysed the heart rate variability. We also evaluated the response of the SAN to cervical vagus nerve stimulation (CVNS). The conditional overexpression of HCN4 did not induce tachycardia, but reduced heart rate variability. The HCN4 overexpression also attenuated bradycardia induced by the CVNS only during the β‐adrenergic stimulation. In contrast, the knockdown of HCN4 gave rise to sinus arrhythmia, and enhanced the parasympathetic response; complete sinus pause was induced by the CVNS. In vitro, we compared the effects of acetylcholine on the spontaneous action potentials of single pacemaker cells, and found that similar phenotypic changes were induced by genetic manipulation of HCN4 expression both in the presence and absence of β‐adrenergic stimulation. Our study suggests that HCN4 channels attenuate the vagal response of the SAN, and thereby stabilize the spontaneous firing of the SAN. The contribution of HCN4 pacemaker channels in the autonomic regulation of the sino‐atrial node (SAN) has been a matter of debate. The transgenic overexpression of HCN4 did not induce tachycardia, but reduced heart rate variability, while the conditional knockdown of HCN4 gave rise to sinus arrhythmia. The response of the SAN to β‐adrenergic stimulation was not affected by overexpression or knockdown of HCN4 channels. When HCN4 channels were knocked down, the parasympathetic response examined by cervical vagus nerve stimulation (CVNS) was enhanced; the CVNS induced complete sinus pause. The overexpression of HCN4 attenuated bradycardia induced by CVNS only during β‐adrenergic stimulation. We concluded that HCN4 pacemaker channels stabilize the spontaneous firing by attenuating the parasympathetic response of the SAN.
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Affiliation(s)
- Yuko Kozasa
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan.,Department of Anesthesiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan
| | - Noriyuki Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan
| | - Masayuki Ito
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
| | - Taisuke Ishikawa
- Department of Molecular Physiology, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan
| | - Hiroki Kimoto
- Department of Molecular Physiology, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan
| | - Kazuo Ushijima
- Department of Anesthesiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan
| | - Naomasa Makita
- Department of Molecular Physiology, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan
| | - Makoto Takano
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan
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Hemodynamic and Electrocardiographic Aspects of Uncomplicated Singleton Pregnancy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1065:413-431. [PMID: 30051399 DOI: 10.1007/978-3-319-77932-4_26] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pregnancy is associated with significant changes in maternal hemodynamics, which are triggered by profound systemic vasodilation and mediated through the autonomic nervous system as well as the renin-angiotensin-aldosterone system. Vascular function changes to help accommodate an increase in intravascular volume due to blood volume expansion associated with pregnancy while maintaining the efficiency of ventricular-arterial coupling and diastolic perfusion pressure. The heart undergoes physiological (eccentric) hypertrophy due to increased volume load and cardiac stroke work, whereas the functional change of the left ventricle remains controversial. There are changes in cardiac electrical activity during pregnancy which can be detected in the electrocardiogram that are not related to disease. Sympathetic activation is a common phenomenon during uncomplicated pregnancy and may be a compensatory mechanism induced by profound systemic vasodilation and a decrease in mean arterial pressure. Despite marked sympathetic activation, vasoconstrictor responsiveness is blunted during uncomplicated pregnancy. There are race and ethnic differences in maternal hemodynamic adaptations to uncomplicated pregnancy, which may be attributed to differences in socioeconomic status or in prevalence rates of cardiovascular risk factors.
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26
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Semmler J, Kormann J, Srinivasan SP, Köster A, Sälzer D, Reppel M, Hescheler J, Plomann M, Nguemo F. Pacsin 2 is required for the maintenance of a normal cardiac function in the developing mouse heart. Pharmacol Res 2017; 128:200-210. [PMID: 29107716 DOI: 10.1016/j.phrs.2017.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 06/26/2017] [Accepted: 10/15/2017] [Indexed: 11/27/2022]
Abstract
The Pacsin proteins (Pacsin 1, 2 and 3) play an important role in intracellular trafficking and thereby signal transduction in many cells types. This study was designed to examine the role of Pacsin 2 in cardiac development and function. We investigated the development and electrophysiological properties of Pacsin 2 knockout (P2KO) hearts and single cardiomyocytes isolated from 11.5 and 15.5days old fetal mice. Immunofluorescence experiments confirmed the lack of Pacsin 2 protein expression in P2KO cardiac myocytes in comparison to wildtype (WT). Western blotting demonstrates low expression levels of connexin 43 and T-box 3 proteins in P2KO compared to wildtype (WT). Electrophysiology measurements including online Multi-Electrode Array (MEA) based field potential (FP) recordings on isolated whole heart of P2KO mice showed a prolonged AV-conduction time. Patch clamp measurements of P2KO cardiomyocytes revealed differences in action potential (AP) parameters and decreased pacemaker funny channel (If), as well as L-type Ca2+ channel (ICaL), and sodium channel (INa). These findings demonstrate that Pacsin 2 is necessary for cardiac development and function in mouse embryos, which will enhance our knowledge to better understand the genesis of cardiovascular diseases.
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Affiliation(s)
- Judith Semmler
- Institute of Neurophysiology, University of Cologne, 50931 Cologne, Germany
| | - Jan Kormann
- Institute of Biochemistry, University of Cologne, 50931 Cologne, Germany
| | | | - Annette Köster
- Institute of Neurophysiology, University of Cologne, 50931 Cologne, Germany
| | - Daniel Sälzer
- Institute of Biochemistry, University of Cologne, 50931 Cologne, Germany
| | - Michael Reppel
- Institute of Neurophysiology, University of Cologne, 50931 Cologne, Germany; Department of Cardiology, University of Lübeck, Lübeck, Germany
| | - Jürgen Hescheler
- Institute of Neurophysiology, University of Cologne, 50931 Cologne, Germany
| | - Markus Plomann
- Institute of Biochemistry, University of Cologne, 50931 Cologne, Germany
| | - Filomain Nguemo
- Institute of Neurophysiology, University of Cologne, 50931 Cologne, Germany.
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27
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Katsi V, Georgiopoulos G, Marketou M, Oikonomou D, Parthenakis F, Makris T, Nihoyannopoulos P, Vardas P, Tousoulis D. Atrial fibrillation in pregnancy: a growing challenge. Curr Med Res Opin 2017; 33:1497-1504. [PMID: 28498066 DOI: 10.1080/03007995.2017.1330257] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) constitutes a relatively infrequent pregnancy complication, which may be a therapeutic Gordian knot. Indeed, sparse data exist regarding the prevalence, prognosis, and management of AF during pregnancy. In general, AF occurs as a benign, self-limited arrhythmia, but occasionally may have severe hemodynamic consequences in pregnant patients suffering from heart failure, congenital heart disease, or other comorbidities. Extra-cardiac causes of AF should always be meticulously excluded. REVIEW Treatment decisions are difficult, since medications may cross the placental barrier and potentially affect fetal growth and organogenesis, or even result in fetal bradyarrhythmias. Treatment goals are not differentiated in comparison to those regarding AF occurring in the general population. Still, while maternal treatment is prioritized, issues regarding fetal health must deliberately be considered. Consequently, hemodynamic instability is to be promptly treated with synchronized electrical cardioversion. In contrast, in stable patients, pharmacologic cardioversion, under appropriate antithrombotic regimen, should be attempted. Selection of appropriate antithrombotic therapy, including novel oral anticoagulants, imposes further difficulties on therapeutic decision-making. Further clinical trials are warranted in order to assess the pathophysiology and prognosis of AF in pregnancy and ameliorate the evidence-based therapeutic strategy in this specific group of the population.
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Affiliation(s)
- Vasiliki Katsi
- a First Department of Cardiology , Hippokration Hospital, University of Athens , Athens , Greece
| | - Georgios Georgiopoulos
- a First Department of Cardiology , Hippokration Hospital, University of Athens , Athens , Greece
| | - Maria Marketou
- b Cardiology Department , Heraklion University Hospital , Crete , Greece
| | - Dimitrios Oikonomou
- a First Department of Cardiology , Hippokration Hospital, University of Athens , Athens , Greece
| | | | - Thomas Makris
- c Cardiology Department , Helena Venizelou Hospital , Athens , Greece
| | - Petros Nihoyannopoulos
- a First Department of Cardiology , Hippokration Hospital, University of Athens , Athens , Greece
| | - P Vardas
- b Cardiology Department , Heraklion University Hospital , Crete , Greece
| | - Dimitris Tousoulis
- a First Department of Cardiology , Hippokration Hospital, University of Athens , Athens , Greece
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28
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Hormones and sex differences: changes in cardiac electrophysiology with pregnancy. Clin Sci (Lond) 2017; 130:747-59. [PMID: 27128800 DOI: 10.1042/cs20150710] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 02/01/2016] [Indexed: 11/17/2022]
Abstract
Disruption of cardiac electrical activity resulting in palpitations and syncope is often an early symptom of pregnancy. Pregnancy is a time of dramatic and dynamic physiological and hormonal changes during which numerous demands are placed on the heart. These changes result in electrical remodelling which can be detected as changes in the electrocardiogram (ECG). This gestational remodelling is a very under-researched area. There are no systematic large studies powered to determine changes in the ECG from pre-pregnancy, through gestation, and into the postpartum period. The large variability between patients and the dynamic nature of pregnancy hampers interpretation of smaller studies, but some facts are consistent. Gestational cardiac hypertrophy and a physical shift of the heart contribute to changes in the ECG. There are also electrical changes such as an increased heart rate and lengthening of the QT interval. There is an increased susceptibility to arrhythmias during pregnancy and the postpartum period. Some changes in the ECG are clearly the result of changes in ion channel expression and behaviour, but little is known about the ionic basis for this electrical remodelling. Most information comes from animal models, and implicates changes in the delayed-rectifier channels. However, it is likely that there are additional roles for sodium channels as well as changes in calcium homoeostasis. The changes in the electrical profile of the heart during pregnancy and the postpartum period have clear implications for the safety of pregnant women, but the field remains relatively undeveloped.
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Vedantham V, Scheinman MM. Familial inappropriate sinus tachycardia: a new chapter in the story of HCN4 channelopathies. Eur Heart J 2017; 38:289-291. [PMID: 28182236 DOI: 10.1093/eurheartj/ehv635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Vasanth Vedantham
- Department of Medicine, Cardiac Electrophysiology Section, University of California-San Francisco, San Francisco, CA, USA
| | - Melvin M Scheinman
- Department of Medicine, Cardiac Electrophysiology Section, University of California-San Francisco, San Francisco, CA, USA
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30
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D'Souza A, Sharma S, Boyett MR. CrossTalk opposing view: bradycardia in the trained athlete is attributable to a downregulation of a pacemaker channel in the sinus node. J Physiol 2016; 593:1749-51. [PMID: 25871551 PMCID: PMC4405729 DOI: 10.1113/jphysiol.2014.284356] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Alicia D'Souza
- Institute of Cardiovascular Sciences, University of Manchester, 46 Grafton Street, Manchester, M13 9NT, UK
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31
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El Gebeily G, El Khoury N, Mathieu S, Brouillette J, Fiset C. Estrogen regulation of the transient outward K(+) current involves estrogen receptor α in mouse heart. J Mol Cell Cardiol 2015. [PMID: 26205295 DOI: 10.1016/j.yjmcc.2015.07.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND AND OBJECTIVE We have previously shown that androgens upregulate cardiac K(+) channels and shorten repolarization. However, the effects that estrogens (E2) and estrogen receptors (ER) might have on the various repolarizing K(+) currents and underlying ion channels remain incompletely understood. Accordingly, our objective was to verify whether and how E2 and its ERs subtypes influence these K(+) currents. METHODS AND RESULTS In order to examine the influence of E2 and ERs on K(+) currents we drastically lowered the E2 level through ovariectomy (OVX; 74% reduction vs CTL) and in parallel, we used female mice lacking either ERα (ERαKO) or ERβ (ERβKO). In OVX mice, results showed a specific increase of 35% in the density of the Ca(2+)-independent transient outward K(+) current (Ito) compared to CTL. Western blots showed increase in Kv4.2 and Kv4.3 sarcolemmal protein expression while qPCR revealed higher mRNA expression of only Kv4.3 in OVX mice. This upregulation of Ito was correlated with a shorter ventricular action potential duration and QTc interval. In ERαKO but not ERβKO mice, the mRNA of Kv4.3 was selectively increased. Furthermore, when ventricular myocytes obtained from ERαKO and ERβKO were cultured in the presence of E2, results showed that E2 reduced Ito density only in ERβKO myocytes confirming the repressive role of E2-ERα in regulating Ito. CONCLUSION Altogether, these results suggest that E2 negatively regulates the density of Ito through ERα, this highlights a potential role for this female hormone and its α-subtype receptor in modulating cardiac electrical activity.
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Affiliation(s)
- Gracia El Gebeily
- Research Center, Montreal Heart Institute, 5000 Bélanger, Montréal, Québec H1T 1C8, Canada; Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada.
| | - Nabil El Khoury
- Research Center, Montreal Heart Institute, 5000 Bélanger, Montréal, Québec H1T 1C8, Canada; Department of Physiology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada.
| | - Sophie Mathieu
- Research Center, Montreal Heart Institute, 5000 Bélanger, Montréal, Québec H1T 1C8, Canada; Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada.
| | - Judith Brouillette
- Research Center, Montreal Heart Institute, 5000 Bélanger, Montréal, Québec H1T 1C8, Canada; Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada.
| | - Céline Fiset
- Research Center, Montreal Heart Institute, 5000 Bélanger, Montréal, Québec H1T 1C8, Canada; Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada.
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32
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Spatiotemporal stability of neonatal rat cardiomyocyte monolayers spontaneous activity is dependent on the culture substrate. PLoS One 2015; 10:e0127977. [PMID: 26035822 PMCID: PMC4452796 DOI: 10.1371/journal.pone.0127977] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 04/21/2015] [Indexed: 11/27/2022] Open
Abstract
In native conditions, cardiac cells must continuously comply with diverse stimuli necessitating a perpetual adaptation. Polydimethylsiloxane (PDMS) is commonly used in cell culture to study cellular response to changes in the mechanical environment. The aim of this study was to evaluate the impact of using PDMS substrates on the properties of spontaneous activity of cardiomyocyte monolayer cultures. We compared PDMS to the gold standard normally used in culture: a glass substrate. Although mean frequency of spontaneous activity remained unaltered, incidence of reentrant activity was significantly higher in samples cultured on glass compared to PDMS substrates. Higher spatial and temporal instability of the spontaneous rate activation was found when cardiomyocytes were cultured on PDMS, and correlated with decreased connexin-43 and increased CaV3.1 and HCN2 mRNA levels. Compared to cultures on glass, cultures on PDMS were associated with the strongest response to isoproterenol and acetylcholine. These results reveal the importance of carefully selecting the culture substrate for studies involving mechanical stimulation, especially for tissue engineering or pharmacological high-throughput screening of cardiac tissue analog.
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33
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Park H, Oh CM, Park J, Park H, Cui S, Kim HS, Namkung J, Park SK, Pak HN, Lee MH, Kim H, Joung B. Deletion of the Serotonin Receptor Type 3A in Mice Leads to Sudden Cardiac Death During Pregnancy. Circ J 2015; 79:1807-15. [PMID: 25986676 DOI: 10.1253/circj.cj-14-1074] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The serotonin receptor type 3 (Htr3) blocker is associated with QT prolongation and torsades de pointes. However, little is known about effects of Htr3 on the heart arrhythmia. METHODS AND RESULTS An electrophysiological study Involving knock-out (KO) female mice lacking functional Htr3a (Htr3a(-/-)) and their wild-type littermates during non-pregancy (NP) and late pregnancy (LP) was performed. Htr3a mRNA was present in the wild-type, but not in the Htr3a(-/-)mouse hearts. Serotonin and tryptophan hydroxylase 1 (Tph1), a rate-limiting enzyme of serotonin synthesis in hearts, is increased during pregnancy. The heart weight and size were increased in the pregnant mice regardless of a mutation. The QTc intervals were prolonged after pregnancy in both the wild (NP: 171.2±16.8 vs. LP: 247.7±14.3 ms; P<0.001) and Htr3a(-/-)mice (NP: 187.9±18.7 vs. LP: 275.6±11.0 ms, P<0.001). Compared with wild-type LP mice, Htr3a(-/-)LP mice had increased spontaneous ventricle tarchycardia (VT; 56% vs. 0%, P=0.002), VT inducibility (66% vs. 25%, P=0.002) and mortality (56% vs. 0%, P=0.002). Pharmacologic administration of serotonin and Htr3 agonists (m-CPBG) decreased the QT interval in wild mice, but not in Htr3a(-/-)mice. CONCLUSIONS Htr3a is present in mouse hearts. Serotonin and Tph1 were increased during pregnancy. The deletion of Htr3a was related to fatal arrhythmias and sudden cardiac death during pregnancy, and its activation reversed the QT prolongation.
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Affiliation(s)
- Hyewon Park
- Division of Cardiology, Yonsei University College of Medicine
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Sex Differences in Cardiac Electrophysiology and Clinical Arrhythmias: Epidemiology, Therapeutics, and Mechanisms. Can J Cardiol 2014; 30:783-92. [DOI: 10.1016/j.cjca.2014.03.032] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 03/23/2014] [Indexed: 11/30/2022] Open
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35
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Affiliation(s)
- Gwilym M Morris
- Institute of Cardiovascular Sciences, University of Manchester, Core Technology Facility
- Department of Cardiology, The Royal Melbourne Hospital
| | - Jonathan M Kalman
- Department of Cardiology, The Royal Melbourne Hospital
- Department of Medicine, Melbourne University
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36
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Ih tunes theta/gamma oscillations and cross-frequency coupling in an in silico CA3 model. PLoS One 2013; 8:e76285. [PMID: 24204609 PMCID: PMC3799898 DOI: 10.1371/journal.pone.0076285] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/22/2013] [Indexed: 11/30/2022] Open
Abstract
channels are uniquely positioned to act as neuromodulatory control points for tuning hippocampal theta (4–12 Hz) and gamma (25 Hz) oscillations, oscillations which are thought to have importance for organization of information flow. contributes to neuronal membrane resonance and resting membrane potential, and is modulated by second messengers. We investigated oscillatory control using a multiscale computer model of hippocampal CA3, where each cell class (pyramidal, basket, and oriens-lacunosum moleculare cells), contained type-appropriate isoforms of . Our model demonstrated that modulation of pyramidal and basket allows tuning theta and gamma oscillation frequency and amplitude. Pyramidal also controlled cross-frequency coupling (CFC) and allowed shifting gamma generation towards particular phases of the theta cycle, effected via 's ability to set pyramidal excitability. Our model predicts that in vivo neuromodulatory control of allows flexibly controlling CFC and the timing of gamma discharges at particular theta phases.
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Wilson CM, Stecyk JAW, Couturier CS, Nilsson GE, Farrell AP. Phylogeny and effects of anoxia on hyperpolarization-activated cyclic nucleotide-gated channel gene expression in the heart of a primitive chordate, the Pacific hagfish (Eptatretus stoutii). ACTA ACUST UNITED AC 2013; 216:4462-72. [PMID: 23997200 DOI: 10.1242/jeb.094912] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aneural heart of the Pacific hagfish, Eptatretus stoutii, varies heart rate fourfold during recovery from anoxia. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which play an important role in establishing the pacemaker rate of vertebrate hearts, were postulated to be present in this ancestral vertebrate heart, and it was also theorized that changes in hagfish heart rate with oxygen availability involved altered HCN expression. Partial gene cloning revealed six HCN isoforms in the hagfish heart. Hagfish representatives of HCN2, HCN3 and HCN4 were discovered, with HCN2 and HCN3 existing as isoforms designated as HCN2a, HCN2b, HCN3a, two paralogs of HCN3b, and HCN3c. Phylogenetic analysis revealed HCN3b and HCN3c to be ancestral, followed by HCN3a, HCN4 and HCN2. Moreover, HCN3a expression was dominant in both the atrial and ventricular chambers, suggesting that the HCN4 dominance in adult mammalian hearts appeared after hagfish divergence. HCN expression was higher in the atrium than in the ventricle, as might be expected given that atrial beating rate is known to be faster than the ventricular rate. In addition, mRNA expression under normoxic conditions was compared with that following 24 h of anoxia, and either a 2-h or 36-h recovery in normoxic water. In the ventricle, anoxia decreased HCN3a but not HCN4 expression. In contrast, atrial HCN3a expression significantly increased following 2 h of recovery, before returning to control levels following 36 h of recovery, possibly contributing to heart rate changes previously observed under these conditions.
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Affiliation(s)
- Christopher M Wilson
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
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Campos FO, Davenport MH, dos Santos RW, Nygren A, Giles WR. High heart rate in pregnancy is modulated by augmented expression of an ion channel, HCN-2, in pacemaker tissue. Circulation 2013; 127:2003-5. [PMID: 23609808 DOI: 10.1161/circulationaha.113.002760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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