1
|
Lubberding AF, Veedfald S, Achter JS, Nissen SD, Soattin L, Sorrentino A, Vega ET, Linz B, Eggertsen CHE, Mulvey J, Toräng S, Larsen SA, Nissen A, Petersen LG, Bilir SE, Bentzen BH, Rosenkilde MM, Hartmann B, Lilleør TNB, Qazi S, Møller CH, Tfelt-Hansen J, Sattler SM, Jespersen T, Holst JJ, Lundby A. GLP-1 increases heart rate by a direct action on the sinus node. Cardiovasc Res 2024:cvae120. [PMID: 38832935 DOI: 10.1093/cvr/cvae120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 04/03/2024] [Accepted: 04/18/2024] [Indexed: 06/06/2024] Open
Abstract
AIMS Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are increasingly used to treat type 2 diabetes and obesity. Albeit cardiovascular outcomes generally improve, treatment with GLP-1 RAs is associated with increased heart rate, the mechanism of which is unclear. METHODS AND RESULTS We employed a large animal model, the female landrace pig, and used multiple in-vivo and ex-vivo approaches including pharmacological challenges, electrophysiology and high-resolution mass spectrometry to explore how GLP-1 elicits an increase in heart rate. In anaesthetized pigs, neither cervical vagotomy, adrenergic blockers (alpha, beta or combined alpha-beta blockade), ganglionic blockade (hexamethonium) nor inhibition of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels (ivabradine) abolished the marked chronotropic effect of GLP-1. GLP-1 administration to isolated perfused pig hearts also increased heart rate, which was abolished by GLP-1 receptor blockade. Electrophysiological characterization of GLP-1 effects in vivo and in isolated perfused hearts localized electrical modulation to the atria and conduction system. In isolated sinus nodes, GLP-1 administration shortened action potential cycle length of pacemaker cells and shifted the site of earliest activation. The effect was independent of HCN blockade. Collectively, these data support a direct effect of GLP-1 on GLP-1 receptors within the heart. Consistently, single nucleus RNA sequencing (snRNAseq) showed GLP-1 receptor expression in porcine pacemaker cells. Quantitative phosphoproteomics analyses of sinus node samples revealed that GLP-1 administration leads to phosphorylation changes of calcium cycling proteins of the sarcoplasmic reticulum, known to regulate heart rate. CONCLUSION GLP-1 has direct chronotropic effects on the heart mediated by GLP-1 receptors in pacemaker cells of the sinus node, inducing changes in action potential morphology and the leading pacemaker site through a calcium signaling response characterized by PKA-dependent phosphorylation of Ca2+ cycling proteins involved in pace making. Targeting the pacemaker calcium clock may be a strategy to lower heart rate in GLP-1 RA recipients.
Collapse
Affiliation(s)
- Anniek Frederike Lubberding
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Simon Veedfald
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonathan Samuel Achter
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sarah Dalgas Nissen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Luca Soattin
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andrea Sorrentino
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Estefania Torres Vega
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Benedikt Linz
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - John Mulvey
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Signe Toräng
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sara Agnete Larsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anne Nissen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lonnie Grove Petersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Secil Erbil Bilir
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bo Hjorth Bentzen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bolette Hartmann
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Nikolaj Bang Lilleør
- Department of Cardiology, Heart Centre, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Saddiq Qazi
- Department of Cardiothoracic Surgery, Rigshospitalet, Denmark
| | | | - Jacob Tfelt-Hansen
- Department of Cardiology, Heart Centre, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
- Department of Forensic Medicine, Faculty of Medical Sciences, University of Copenhagen, Frederik V's Vej, 2100 Copenhagen, Denmark
| | - Stefan Michael Sattler
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Cardiology, Herlev and Gentofte University Hospital, Hellerup, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Alicia Lundby
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
2
|
Hennis K, Piantoni C, Biel M, Fenske S, Wahl-Schott C. Pacemaker Channels and the Chronotropic Response in Health and Disease. Circ Res 2024; 134:1348-1378. [PMID: 38723033 PMCID: PMC11081487 DOI: 10.1161/circresaha.123.323250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/13/2024]
Abstract
Loss or dysregulation of the normally precise control of heart rate via the autonomic nervous system plays a critical role during the development and progression of cardiovascular disease-including ischemic heart disease, heart failure, and arrhythmias. While the clinical significance of regulating changes in heart rate, known as the chronotropic effect, is undeniable, the mechanisms controlling these changes remain not fully understood. Heart rate acceleration and deceleration are mediated by increasing or decreasing the spontaneous firing rate of pacemaker cells in the sinoatrial node. During the transition from rest to activity, sympathetic neurons stimulate these cells by activating β-adrenergic receptors and increasing intracellular cyclic adenosine monophosphate. The same signal transduction pathway is targeted by positive chronotropic drugs such as norepinephrine and dobutamine, which are used in the treatment of cardiogenic shock and severe heart failure. The cyclic adenosine monophosphate-sensitive hyperpolarization-activated current (If) in pacemaker cells is passed by hyperpolarization-activated cyclic nucleotide-gated cation channels and is critical for generating the autonomous heartbeat. In addition, this current has been suggested to play a central role in the chronotropic effect. Recent studies demonstrate that cyclic adenosine monophosphate-dependent regulation of HCN4 (hyperpolarization-activated cyclic nucleotide-gated cation channel isoform 4) acts to stabilize the heart rate, particularly during rapid rate transitions induced by the autonomic nervous system. The mechanism is based on creating a balance between firing and recently discovered nonfiring pacemaker cells in the sinoatrial node. In this way, hyperpolarization-activated cyclic nucleotide-gated cation channels may protect the heart from sinoatrial node dysfunction, secondary arrhythmia of the atria, and potentially fatal tachyarrhythmia of the ventricles. Here, we review the latest findings on sinoatrial node automaticity and discuss the physiological and pathophysiological role of HCN pacemaker channels in the chronotropic response and beyond.
Collapse
Affiliation(s)
- Konstantin Hennis
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
| | - Chiara Piantoni
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
| | - Martin Biel
- Department of Pharmacy, Center for Drug Research (M.B., S.F.), Ludwig-Maximilians-Universität München, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Germany (M.B., S.F.)
| | - Stefanie Fenske
- Department of Pharmacy, Center for Drug Research (M.B., S.F.), Ludwig-Maximilians-Universität München, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Germany (M.B., S.F.)
| | - Christian Wahl-Schott
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
| |
Collapse
|
3
|
Zaytseva AK, Kulichik OE, Kostareva AA, Zhorov BS. Biophysical mechanisms of myocardium sodium channelopathies. Pflugers Arch 2024; 476:735-753. [PMID: 38424322 DOI: 10.1007/s00424-024-02930-3] [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: 09/28/2023] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 03/02/2024]
Abstract
Genetic variants of gene SCN5A encoding the alpha-subunit of cardiac voltage-gated sodium channel Nav1.5 are associated with various diseases, including long QT syndrome (LQT3), Brugada syndrome (BrS1), and progressive cardiac conduction disease (PCCD). In the last decades, the great progress in understanding molecular and biophysical mechanisms of these diseases has been achieved. The LQT3 syndrome is associated with gain-of-function of sodium channels Nav1.5 due to impaired inactivation, enhanced activation, accelerated recovery from inactivation or the late current appearance. In contrast, BrS1 and PCCD are associated with the Nav1.5 loss-of-function, which in electrophysiological experiments can be manifested as reduced current density, enhanced fast or slow inactivation, impaired activation, or decelerated recovery from inactivation. Genetic variants associated with congenital arrhythmias can also disturb interactions of the Nav1.5 channel with different proteins or drugs and cause unexpected reactions to drug administration. Furthermore, mutations can affect post-translational modifications of the channels and their sensitivity to pH and temperature. Here we briefly review the current knowledge on biophysical mechanisms of LQT3, BrS1 and PCCD. We focus on limitations of studies that use heterologous expression systems and induced pluripotent stem cells (iPSC) derived cardiac myocytes and summarize our understanding of genotype-phenotype relations of SCN5A mutations.
Collapse
Affiliation(s)
- Anastasia K Zaytseva
- Almazov National Medical Research Centre, St. Petersburg, Russia.
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
| | - Olga E Kulichik
- Almazov National Medical Research Centre, St. Petersburg, Russia
| | | | - Boris S Zhorov
- Almazov National Medical Research Centre, St. Petersburg, Russia
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
- McMaster University, Hamilton, Canada
| |
Collapse
|
4
|
Wei N, Lee C, Duan L, Galdos FX, Samad T, Raissadati A, Goodyer WR, Wu SM. Cardiac Development at a Single-Cell Resolution. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1441:253-268. [PMID: 38884716 DOI: 10.1007/978-3-031-44087-8_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Mammalian cardiac development is a complex, multistage process. Though traditional lineage tracing studies have characterized the broad trajectories of cardiac progenitors, the advent and rapid optimization of single-cell RNA sequencing methods have yielded an ever-expanding toolkit for characterizing heterogeneous cell populations in the developing heart. Importantly, they have allowed for a robust profiling of the spatiotemporal transcriptomic landscape of the human and mouse heart, revealing the diversity of cardiac cells-myocyte and non-myocyte-over the course of development. These studies have yielded insights into novel cardiac progenitor populations, chamber-specific developmental signatures, the gene regulatory networks governing cardiac development, and, thus, the etiologies of congenital heart diseases. Furthermore, single-cell RNA sequencing has allowed for the exquisite characterization of distinct cardiac populations such as the hard-to-capture cardiac conduction system and the intracardiac immune population. Therefore, single-cell profiling has also resulted in new insights into the regulation of cardiac regeneration and injury repair. Single-cell multiomics approaches combining transcriptomics, genomics, and epigenomics may uncover an even more comprehensive atlas of human cardiac biology. Single-cell analyses of the developing and adult mammalian heart offer an unprecedented look into the fundamental mechanisms of cardiac development and the complex diseases that may arise from it.
Collapse
Affiliation(s)
- Nicholas Wei
- Stanford University, Cardiovascular Institute, Stanford, CA, USA
| | - Carissa Lee
- Stanford University, Cardiovascular Institute, Stanford, CA, USA
| | - Lauren Duan
- Stanford University, Cardiovascular Institute, Stanford, CA, USA
| | | | - Tahmina Samad
- Stanford University, Cardiovascular Institute, Stanford, CA, USA
| | | | | | - Sean M Wu
- Stanford University, Cardiovascular Institute, Stanford, CA, USA.
| |
Collapse
|
5
|
Asjad E, Dobrzynski H. MicroRNAs: Midfielders of Cardiac Health, Disease and Treatment. Int J Mol Sci 2023; 24:16207. [PMID: 38003397 PMCID: PMC10671258 DOI: 10.3390/ijms242216207] [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: 09/22/2023] [Revised: 11/05/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that play a role in post-transcriptional gene regulation. It is generally accepted that their main mechanism of action is the negative regulation of gene expression, through binding to specific regions in messenger RNA (mRNA) and repressing protein translation. By interrupting protein synthesis, miRNAs can effectively turn genes off and influence many basic processes in the body, such as developmental and apoptotic behaviours of cells and cardiac organogenesis. Their importance is highlighted by inhibiting or overexpressing certain miRNAs, which will be discussed in the context of coronary artery disease, atrial fibrillation, bradycardia, and heart failure. Dysregulated levels of miRNAs in the body can exacerbate or alleviate existing disease, and their omnipresence in the body makes them reliable as quantifiable markers of disease. This review aims to provide a summary of miRNAs as biomarkers and their interactions with targets that affect cardiac health, and intersperse it with current therapeutic knowledge. It intends to succinctly inform on these topics and guide readers toward more comprehensive works if they wish to explore further through a wide-ranging citation list.
Collapse
Affiliation(s)
- Emman Asjad
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK;
| | - Halina Dobrzynski
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK;
- Department of Anatomy, Jagiellonian University Medical College, 31-034 Krakow, Poland
| |
Collapse
|
6
|
Kim D, Kim N, Lee Y, Kim S, Kwon J. Sound stimulation using the individual's heart rate to improve the stability and homeostasis of the autonomic nervous system. Physiol Rep 2023; 11:e15816. [PMID: 37726255 PMCID: PMC10509153 DOI: 10.14814/phy2.15816] [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: 06/16/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/21/2023] Open
Abstract
OBJECTIVES In this study, we explain the role of enhancing the stability and homeostasis of the autonomic nervous system (ANS) by proposing the average heart rate sound resonance (aHRSR), a sound stimulation to prevent imbalance of ANS due to dynamic movement. The effect of aHRSR on ANS was analyzed through the time and frequency domain of heart rate variability (HRV) using the photoplethysmogram data (PPG) of 22 participants (DUIRB-202109-12). METHOD When the subjects performed dynamic movements that could cause changes in the ANS, HRV indicators using PPG data for 5 min before and after the movements were analyzed according to the presence or absence of aHRSR. The standard deviation of the NN intervals (SDNN), the square root of the mean squared differences of the NN intervals (RMSSD), low-frequency band (LF), and high-frequency band (HF), which represent sympathetic and parasympathetic nerve activity, were used as indicators, where SNDD and LF represent total ANS and sympathetic activity, while RMSSD and HF represent parasympathetic activity. RESULTS As the effects of aHRSR on dynamic movement, the recovery time of RR interval was advanced by about 15 s, SDNN increased from ([44.16 ± 13.11] to [47.85 ± 15.16]) ms, and RMSSD increased from ([23.73 ± 9.95] to [31.89 ± 12.48]) ms (p < 0.05), increasing the stability of the ANS and reducing instability. The effect of homeostasis of the ANS according to aHRSR is also shown in reducing the change rate of LF from (-13.83 to -8.83) %, and the rate of change of HF from (10.59 to 3.27) %. CONCLUSIONS These results suggest that aHRSR can affect the cardiovascular system by assisting physiological movements that occur during dynamic movement.
Collapse
Affiliation(s)
- Daechang Kim
- Department of Medical BiotechnologyDongguk UniversityGyeonggi‐doKorea
| | - Nahyeon Kim
- Department of Medical BiotechnologyDongguk UniversityGyeonggi‐doKorea
| | - Younju Lee
- Department of Medical BiotechnologyDongguk UniversityGyeonggi‐doKorea
| | - Sungmin Kim
- Department of Medical BiotechnologyDongguk UniversityGyeonggi‐doKorea
| | - Jiyean Kwon
- Department of Medical Device and HealthcareDongguk UniversitySeoulKorea
| |
Collapse
|
7
|
Aldughayfiq B, Ashfaq F, Jhanjhi NZ, Humayun M. A Deep Learning Approach for Atrial Fibrillation Classification Using Multi-Feature Time Series Data from ECG and PPG. Diagnostics (Basel) 2023; 13:2442. [PMID: 37510187 PMCID: PMC10377944 DOI: 10.3390/diagnostics13142442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/08/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Atrial fibrillation is a prevalent cardiac arrhythmia that poses significant health risks to patients. The use of non-invasive methods for AF detection, such as Electrocardiogram and Photoplethysmogram, has gained attention due to their accessibility and ease of use. However, there are challenges associated with ECG-based AF detection, and the significance of PPG signals in this context has been increasingly recognized. The limitations of ECG and the untapped potential of PPG are taken into account as this work attempts to classify AF and non-AF using PPG time series data and deep learning. In this work, we emploted a hybrid deep neural network comprising of 1D CNN and BiLSTM for the task of AF classification. We addressed the under-researched area of applying deep learning methods to transmissive PPG signals by proposing a novel approach. Our approach involved integrating ECG and PPG signals as multi-featured time series data and training deep learning models for AF classification. Our hybrid 1D CNN and BiLSTM model achieved an accuracy of 95% on test data in identifying atrial fibrillation, showcasing its strong performance and reliable predictive capabilities. Furthermore, we evaluated the performance of our model using additional metrics. The precision of our classification model was measured at 0.88, indicating its ability to accurately identify true positive cases of AF. The recall, or sensitivity, was measured at 0.85, illustrating the model's capacity to detect a high proportion of actual AF cases. Additionally, the F1 score, which combines both precision and recall, was calculated at 0.84, highlighting the overall effectiveness of our model in classifying AF and non-AF cases.
Collapse
Affiliation(s)
- Bader Aldughayfiq
- Department of Information Systems, College of Computer and Information Sciences, Jouf University, Sakaka 72388, Saudi Arabia
| | - Farzeen Ashfaq
- School of Computer Science, SCS, Taylor's University, Subang Jaya 47500, Malaysia
| | - N Z Jhanjhi
- School of Computer Science, SCS, Taylor's University, Subang Jaya 47500, Malaysia
| | - Mamoona Humayun
- Department of Information Systems, College of Computer and Information Sciences, Jouf University, Sakaka 72388, Saudi Arabia
| |
Collapse
|
8
|
Liu T, Li T, Xu D, Wang Y, Zhou Y, Wan J, Huang CLH, Tan X. Small-conductance calcium-activated potassium channels in the heart: expression, regulation and pathological implications. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220171. [PMID: 37122223 PMCID: PMC10150224 DOI: 10.1098/rstb.2022.0171] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/25/2022] [Indexed: 05/02/2023] Open
Abstract
Ca2+-activated K+ channels are critical to cellular Ca2+ homeostasis and excitability; they couple intracellular Ca2+ and membrane voltage change. Of these, the small, 4-14 pS, conductance SK channels include three, KCNN1-3 encoded, SK1/KCa2.1, SK2/KCa2.2 and SK3/KCa2.3, channel subtypes with characteristic, EC50 ∼ 10 nM, 40 pM, 1 nM, apamin sensitivities. All SK channels, particularly SK2 channels, are expressed in atrial, ventricular and conducting system cardiomyocytes. Pharmacological and genetic modification results have suggested that SK channel block or knockout prolonged action potential durations (APDs) and effective refractory periods (ERPs) particularly in atrial, but also in ventricular, and sinoatrial, atrioventricular node and Purkinje myocytes, correspondingly affect arrhythmic tendency. Additionally, mitochondrial SK channels may decrease mitochondrial Ca2+ overload and reactive oxygen species generation. SK channels show low voltage but marked Ca2+ dependences (EC50 ∼ 300-500 nM) reflecting their α-subunit calmodulin (CaM) binding domains, through which they may be activated by voltage-gated or ryanodine-receptor Ca2+ channel activity. SK function also depends upon complex trafficking and expression processes and associations with other ion channels or subunits from different SK subtypes. Atrial and ventricular clinical arrhythmogenesis may follow both increased or decreased SK expression through decreased or increased APD correspondingly accelerating and stabilizing re-entrant rotors or increasing incidences of triggered activity. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
Collapse
Affiliation(s)
- Ting Liu
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Tao Li
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Cardiology, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Dandi Xu
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Yan Wang
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Yafei Zhou
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Juyi Wan
- Department of Cardiovascular Surgery, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Christopher L.-H. Huang
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Physiological Laboratory and Department of Biochemistry, University of Cambridge, Cambridge CB2 3EG, UK
| | - Xiaoqiu Tan
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Cardiology, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Physiology, School of Basic Medical Sciences, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| |
Collapse
|
9
|
Henley T, Goudy J, Easterling M, Donley C, Wirka R, Bressan M. Local tissue mechanics control cardiac pacemaker cell embryonic patterning. Life Sci Alliance 2023; 6:e202201799. [PMID: 36973005 PMCID: PMC10043993 DOI: 10.26508/lsa.202201799] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 03/13/2023] [Accepted: 03/15/2023] [Indexed: 03/29/2023] Open
Abstract
Cardiac pacemaker cells (CPCs) initiate the electric impulses that drive the rhythmic beating of the heart. CPCs reside in a heterogeneous, ECM-rich microenvironment termed the sinoatrial node (SAN). Surprisingly, little is known regarding the biochemical composition or mechanical properties of the SAN, and how the unique structural characteristics present in this region of the heart influence CPC function remains poorly understood. Here, we have identified that SAN development involves the construction of a "soft" macromolecular ECM that specifically encapsulates CPCs. In addition, we demonstrate that subjecting embryonic CPCs to substrate stiffnesses higher than those measured in vivo results in loss of coherent electrical oscillation and dysregulation of the HCN4 and NCX1 ion channels required for CPC automaticity. Collectively, these data indicate that local mechanics play a critical role in maintaining the embryonic CPC function while also quantitatively defining the range of material properties that are optimal for embryonic CPC maturation.
Collapse
Affiliation(s)
- Trevor Henley
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Julie Goudy
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Marietta Easterling
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Carrie Donley
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Robert Wirka
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Michael Bressan
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| |
Collapse
|
10
|
Zheng H, Peri L, Ward GK, Sanders KM, Ward SM. Cardiac PDGFRα + interstitial cells generate spontaneous inward currents that contribute to excitability in the heart. FASEB J 2023; 37:e22929. [PMID: 37086093 PMCID: PMC10402933 DOI: 10.1096/fj.202201712r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 03/06/2023] [Accepted: 04/05/2023] [Indexed: 04/23/2023]
Abstract
The cell types and conductance that contribute to normal cardiac functions remain under investigation. We used mice that express an enhanced green fluorescent protein (eGFP)-histone 2B fusion protein driven off the cell-specific endogenous promoter for Pdgfra to investigate the distribution and functional role of PDGFRα+ cells in the heart. Cardiac PDGFRα+ cells were widely distributed within the endomysium of atria, ventricle, and sino-atrial node (SAN) tissues. PDGFRα+ cells formed a discrete network of cells, lying in close apposition to neighboring cardiac myocytes in mouse and Cynomolgus monkey (Macaca fascicularis) hearts. Expression of eGFP in nuclei allowed unequivocal identification of these cells following enzymatic dispersion of muscle tissues. FACS purification of PDGFRα+ cells from the SAN and analysis of gene transcripts by qPCR revealed that they were a distinct population of cells that expressed gap junction transcripts, Gja1 and Gjc1. Cardiac PDGFRα+ cells generated spontaneous transient inward currents (STICs) and spontaneous transient depolarizations (STDs) that reversed at 0 mV. Reversal potential was maintained when ECl = -40 mV. [Na+ ]o replacement and FTY720 abolished STICs, suggesting they were due to a non-selective cation conductance (NSCC) carried by TRPM7. PDGFRα+ cells also express β2 -adrenoceptor gene transcripts, Adrb2. Zinterol, a selective β2 -receptor agonist, increased the amplitude and frequency of STICs, suggesting these cells could contribute to adrenergic regulation of cardiac excitability. PDGFRα+ cells in cardiac muscles generate inward currents via an NSCC. STICs generated by these cells may contribute to the integrated membrane potentials of cardiac muscles, possibly affecting the frequency of pacemaker activity.
Collapse
Affiliation(s)
- Haifeng Zheng
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Lauren Peri
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Grace K. Ward
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Kenton M. Sanders
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Sean M. Ward
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| |
Collapse
|
11
|
Hatthakone T, Oundavong S, Soejima Y, Sawabe M. Development of a new histological identification method of human sinoatrial node suitable for immunohistochemical study. Anat Sci Int 2023; 98:293-305. [PMID: 36422826 DOI: 10.1007/s12565-022-00697-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/07/2022] [Indexed: 11/27/2022]
Abstract
Histological identification of the human sinoatrial node (SAN) remains a challenge. Conventional identification methods, such as Lev's method, have certain limitations. The aim of our study was to develop a new histological identification method that could properly identify the sinoatrial node, applicable to the immunohistochemical study of intra-nodal structures. Thirty-nine human autopsied hearts were included in this study. The cases included 23 men and 16 women ranging in age from 20 to 99 years. The sinoatrial area from eight control samples was cut in the vertical section using the conventional Lev's method. In our new method, called the "En face one-block method," the sinoatrial node was cut in "En face" at the junction of the right border of the right appendage and superior vena cava, placed in one long cassette, and serially cut using a microtome. Immunostaining was performed using primary antibodies against CD31, podoplanin (D2-40), S-100, and other proteins. The average area of the SAN on the slide glass in our new method was 32.2 mm2, which was significantly larger than that (3.59 mm2) of the control samples by Lev's method. The SAN area was positively correlated with age (r = 0.357; p = 0.026), especially in women (r = 0.626; p = 0.0095). The SAN group had significantly lower percentage of CD31-positive blood capillaries, higher percentage of podoplanin-positive lymphatic channels, and S-100-positive peripheral nerves. We successfully developed a novel cutting method applicable to immunohistochemical studies, with which we could provide a bird's-eye view of the sinoatrial nodes.
Collapse
Affiliation(s)
- Thavisouk Hatthakone
- Department of Molecular Pathology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8510, Japan
| | - Sunti Oundavong
- Department of Molecular Pathology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8510, Japan
| | - Yurie Soejima
- Department of Molecular Pathology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8510, Japan
| | - Motoji Sawabe
- Department of Molecular Pathology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8510, Japan.
- Department of Molecular Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan.
- Department of Diagnostic Pathology, Hitachi General Hospital, 2-1-1 Jonancho, Hitachi, Ibaraki, 317-0077, Japan.
| |
Collapse
|
12
|
Nashiro K, Min J, Yoo HJ, Cho C, Bachman SL, Dutt S, Thayer JF, Lehrer PM, Feng T, Mercer N, Nasseri P, Wang D, Chang C, Marmarelis VZ, Narayanan S, Nation DA, Mather M. Increasing coordination and responsivity of emotion-related brain regions with a heart rate variability biofeedback randomized trial. COGNITIVE, AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2023; 23:66-83. [PMID: 36109422 PMCID: PMC9931635 DOI: 10.3758/s13415-022-01032-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/25/2022] [Indexed: 12/15/2022]
Abstract
Heart rate variability is a robust biomarker of emotional well-being, consistent with the shared brain networks regulating emotion regulation and heart rate. While high heart rate oscillatory activity clearly indicates healthy regulatory brain systems, can increasing this oscillatory activity also enhance brain function? To test this possibility, we randomly assigned 106 young adult participants to one of two 5-week interventions involving daily biofeedback that either increased heart rate oscillations (Osc+ condition) or had little effect on heart rate oscillations (Osc- condition) and examined effects on brain activity during rest and during regulating emotion. While there were no significant changes in the right amygdala-medial prefrontal cortex (MPFC) functional connectivity (our primary outcome), the Osc+ intervention increased left amygdala-MPFC functional connectivity and functional connectivity in emotion-related resting-state networks during rest. It also increased down-regulation of activity in somatosensory brain regions during an emotion regulation task. The Osc- intervention did not have these effects. In this healthy cohort, the two conditions did not differentially affect anxiety, depression, or mood. These findings indicate that modulating heart rate oscillatory activity changes emotion network coordination in the brain.
Collapse
Affiliation(s)
- Kaoru Nashiro
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | - Jungwon Min
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | - Hyun Joo Yoo
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | - Christine Cho
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | - Shelby L Bachman
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | - Shubir Dutt
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | | | | | - Tiantian Feng
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | - Noah Mercer
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | - Padideh Nasseri
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | - Diana Wang
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | | | - Vasilis Z Marmarelis
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | - Shri Narayanan
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA
| | | | - Mara Mather
- University of Southern California, 3715 McClintock Avenue, Los Angeles, CA, 90089, USA.
| |
Collapse
|
13
|
Ricci E, Bartolucci C, Severi S. The virtual sinoatrial node: What did computational models tell us about cardiac pacemaking? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 177:55-79. [PMID: 36374743 DOI: 10.1016/j.pbiomolbio.2022.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 10/17/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022]
Abstract
Since its discovery, the sinoatrial node (SAN) has represented a fascinating and complex matter of research. Despite over a century of discoveries, a full comprehension of pacemaking has still to be achieved. Experiments often produced conflicting evidence that was used either in support or against alternative theories, originating intense debates. In this context, mathematical descriptions of the phenomena underlying the heartbeat have grown in importance in the last decades since they helped in gaining insights where experimental evaluation could not reach. This review presents the most updated SAN computational models and discusses their contribution to our understanding of cardiac pacemaking. Electrophysiological, structural and pathological aspects - as well as the autonomic control over the SAN - are taken into consideration to reach a holistic view of SAN activity.
Collapse
Affiliation(s)
- Eugenio Ricci
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena (FC), Italy
| | - Chiara Bartolucci
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena (FC), Italy
| | - Stefano Severi
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena (FC), Italy.
| |
Collapse
|
14
|
The Effect of the Tongyang Huoxue Recipe (TYHX) on the I to/ I Kur in Ischemia/Reperfusion Sinoatrial Node Cells. Cardiovasc Ther 2022; 2022:4114817. [PMID: 36605374 PMCID: PMC9794430 DOI: 10.1155/2022/4114817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/26/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022] Open
Abstract
Background The transient outward potassium current (I to) and the ultrarapid delayed rectifier potassium current (I Kur) are major potassium currents involved in the repolarization process of sinoatrial node cells (SNCs). Methods and Results The SNCs of neonatal rats were divided into control, ischemia/reperfusion (I/R), I/R+blank serum, and Tongyang Huoxue recipe (TYHX) serum groups. I to and I Kur were recorded using the whole cell patch-clamp technique, and the current-voltage (I-V), steady-state activation (SSA), steady-state inactivation (SSI), and recovery from inactivation (RFI) curves were plotted, respectively. Compared to the control group, both the peak current density and the current density at the voltage of I to and I Kur decreased obviously in SNCs after simulated I/R, the SSA curves moved right, and the SSI curves moved left. After TYHX was added to the extracellular solution of SNCs, both the peak current density and the current density at the voltage of I to and I Kur increased significantly, the SSA curves moved left, and the SSI curves moved right with a significant difference of V 1/2. The recovery from the I Kur RFI curves was slightly restored, and the I to curves did not change. Conclusions TYHX increases the peak current density, accelerates the activation, and decreases the inactivation of the I to and I Kur. This may be the mechanism of TYHX in shortening the action potential duration of repolarization, which accelerates spontaneous pulsation.
Collapse
|
15
|
Amsaleg A, Sánchez J, Mikut R, Loewe A. Characterization of the pace-and-drive capacity of the human sinoatrial node: A 3D in silico study. Biophys J 2022; 121:4247-4259. [PMID: 36262044 PMCID: PMC9703096 DOI: 10.1016/j.bpj.2022.10.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 09/20/2022] [Accepted: 10/13/2022] [Indexed: 12/14/2022] Open
Abstract
The sinoatrial node (SAN) is a complex structure that spontaneously depolarizes rhythmically ("pacing") and excites the surrounding non-automatic cardiac cells ("drive") to initiate each heart beat. However, the mechanisms by which the SAN cells can activate the large and hyperpolarized surrounding cardiac tissue are incompletely understood. Experimental studies demonstrated the presence of an insulating border that separates the SAN from the hyperpolarizing influence of the surrounding myocardium, except at a discrete number of sinoatrial exit pathways (SEPs). We propose a highly detailed 3D model of the human SAN, including 3D SEPs to study the requirements for successful electrical activation of the primary pacemaking structure of the human heart. A total of 788 simulations investigate the ability of the SAN to pace and drive with different heterogeneous characteristics of the nodal tissue (gradient and mosaic models) and myocyte orientation. A sigmoidal distribution of the tissue conductivity combined with a mosaic model of SAN and atrial cells in the SEP was able to drive the right atrium (RA) at varying rates induced by gradual If block. Additionally, we investigated the influence of the SEPs by varying their number, length, and width. SEPs created a transition zone of transmembrane voltage and ionic currents to enable successful pace and drive. Unsuccessful simulations showed a hyperpolarized transmembrane voltage (-66 mV), which blocked the L-type channels and attenuated the sodium-calcium exchanger. The fiber direction influenced the SEPs that preferentially activated the crista terminalis (CT). The location of the leading pacemaker site (LPS) shifted toward the SEP-free areas. LPSs were located closer to the SEP-free areas (3.46 ± 1.42 mm), where the hyperpolarizing influence of the CT was reduced, compared with a larger distance from the LPS to the areas where SEPs were located (7.17± 0.98 mm). This study identified the geometrical and electrophysiological aspects of the 3D SAN-SEP-CT structure required for successful pace and drive in silico.
Collapse
Affiliation(s)
- Antoine Amsaleg
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Jorge Sánchez
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Ralf Mikut
- Institute for Automation and Applied Informatics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Axel Loewe
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
| |
Collapse
|
16
|
Grainger N, Santana LF. The Inferior Sinoatrial Node Suffers the Most During Heart Failure. JACC Clin Electrophysiol 2022; 8:1354-1356. [PMID: 36424001 PMCID: PMC10031657 DOI: 10.1016/j.jacep.2022.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 09/03/2022] [Indexed: 11/22/2022]
Affiliation(s)
- Nathan Grainger
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA.
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California, USA.
| |
Collapse
|
17
|
Campana C, Ricci E, Bartolucci C, Severi S, Sobie EA. Coupling and heterogeneity modulate pacemaking capability in healthy and diseased two-dimensional sinoatrial node tissue models. PLoS Comput Biol 2022; 18:e1010098. [PMID: 36409762 DOI: 10.1371/journal.pcbi.1010098] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 12/14/2022] [Accepted: 11/04/2022] [Indexed: 11/22/2022] Open
Abstract
Both experimental and modeling studies have attempted to determine mechanisms by which a small anatomical region, such as the sinoatrial node (SAN), can robustly drive electrical activity in the human heart. However, despite many advances from prior research, important questions remain unanswered. This study aimed to investigate, through mathematical modeling, the roles of intercellular coupling and cellular heterogeneity in synchronization and pacemaking within the healthy and diseased SAN. In a multicellular computational model of a monolayer of either human or rabbit SAN cells, simulations revealed that heterogenous cells synchronize their discharge frequency into a unique beating rhythm across a wide range of heterogeneity and intercellular coupling values. However, an unanticipated behavior appeared under pathological conditions where perturbation of ionic currents led to reduced excitability. Under these conditions, an intermediate range of intercellular coupling (900-4000 MΩ) was beneficial to SAN automaticity, enabling a very small portion of tissue (3.4%) to drive propagation, with propagation failure occurring at both lower and higher resistances. This protective effect of intercellular coupling and heterogeneity, seen in both human and rabbit tissues, highlights the remarkable resilience of the SAN. Overall, the model presented in this work allowed insight into how spontaneous beating of the SAN tissue may be preserved in the face of perturbations that can cause individual cells to lose automaticity. The simulations suggest that certain degrees of gap junctional coupling protect the SAN from ionic perturbations that can be caused by drugs or mutations.
Collapse
Affiliation(s)
- Chiara Campana
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Eugenio Ricci
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy
| | - Chiara Bartolucci
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy
| | - Stefano Severi
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy
| | - Eric A Sobie
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| |
Collapse
|
18
|
Kuzmin VS, Malykhina IA, Pustovit KB, Ivanova AD, Kuniewicz M, Walocha J, Atkinson A, Aminu AJ, Dobrzynski H. Inflammatory degranulation of the cardiac resident mast cells suppresses the pacemaking and affects activation pattern in the sinoatrial node. TRANSLATIONAL RESEARCH IN ANATOMY 2022. [DOI: 10.1016/j.tria.2022.100170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|
19
|
Al Kury LT, Chacar S, Alefishat E, Khraibi AA, Nader M. Structural and Electrical Remodeling of the Sinoatrial Node in Diabetes: New Dimensions and Perspectives. Front Endocrinol (Lausanne) 2022; 13:946313. [PMID: 35872997 PMCID: PMC9302195 DOI: 10.3389/fendo.2022.946313] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/14/2022] [Indexed: 11/14/2022] Open
Abstract
The sinoatrial node (SAN) is composed of highly specialized cells that mandate the spontaneous beating of the heart through self-generation of an action potential (AP). Despite this automaticity, the SAN is under the modulation of the autonomic nervous system (ANS). In diabetes mellitus (DM), heart rate variability (HRV) manifests as a hallmark of diabetic cardiomyopathy. This is paralleled by an impaired regulation of the ANS, and by a pathological remodeling of the pacemaker structure and function. The direct effect of diabetes on the molecular signatures underscoring this pathology remains ill-defined. The recent focus on the electrical currents of the SAN in diabetes revealed a repressed firing rate of the AP and an elongation of its tracing, along with conduction abnormalities and contractile failure. These changes are blamed on the decreased expression of ion transporters and cell-cell communication ports at the SAN (i.e., HCN4, calcium and potassium channels, connexins 40, 45, and 46) which further promotes arrhythmias. Molecular analysis crystallized the RGS4 (regulator of potassium currents), mitochondrial thioredoxin-2 (reactive oxygen species; ROS scavenger), and the calcium-dependent calmodulin kinase II (CaMKII) as metabolic culprits of relaying the pathological remodeling of the SAN cells (SANCs) structure and function. A special attention is given to the oxidation of CaMKII and the generation of ROS that induce cell damage and apoptosis of diabetic SANCs. Consequently, the diabetic SAN contains a reduced number of cells with significant infiltration of fibrotic tissues that further delay the conduction of the AP between the SANCs. Failure of a genuine generation of AP and conduction of their derivative waves to the neighboring atrial myocardium may also occur as a result of the anti-diabetic regiment (both acute and/or chronic treatments). All together, these changes pose a challenge in the field of cardiology and call for further investigations to understand the etiology of the structural/functional remodeling of the SANCs in diabetes. Such an understanding may lead to more adequate therapies that can optimize glycemic control and improve health-related outcomes in patients with diabetes.
Collapse
Affiliation(s)
- Lina T. Al Kury
- Department of Health Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi, United Arab Emirates
- *Correspondence: Lina T. Al Kury, ; Moni Nader,
| | - Stephanie Chacar
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Eman Alefishat
- Department of Pharmacology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- Department of Biopharmaceutics and Clinical Pharmacy, School of Pharmacy, The University of Jordan, Amman, Jordan
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Ali A. Khraibi
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Moni Nader
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- *Correspondence: Lina T. Al Kury, ; Moni Nader,
| |
Collapse
|
20
|
Seo J, Spalla I, Porteiro Vázquez DM, Luis Fuentes V, Tinson E, Connolly DJ. Rhythm disturbances associated with lidocaine administration in four dogs with supraventricular tachyarrhythmias. J Vet Emerg Crit Care (San Antonio) 2021; 32:106-112. [PMID: 34699678 DOI: 10.1111/vec.13151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/28/2020] [Accepted: 08/23/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To describe arrhythmias associated with administration of lidocaine in dogs treated for supraventricular tachyarrhythmias. CASE SUMMARIES Four dogs with recent-onset supraventricular tachyarrhythmias: 3 dogs had atrial fibrillation (AF), and 1 had focal atrial tachycardia (FAT), which was thought to be AF at the time of assessment. The substrate of the supraventricular tachyarrhythmia was considered to be due to primary cardiomyopathy in 1 dog, high vagal tone in 2 dogs, and the change in hemodynamics from heavy sedation in 1 dog. Pharmacological cardioversion using lidocaine was only successful in the 2 dogs with vagally mediated AF. In these 2 cases, lidocaine administration resulted in a paroxysmal atrial flutter that was self-limiting and quickly led to sinus rhythm within 10 seconds in 1 dog but did not change over a 5-minute interval and required additional boluses in another dog. In the latter case, the dog showed severe bradycardia for 17.5 seconds prior to achieving sinus rhythm. The 2 unsuccessful cases both developed ventricular arrhythmias shortly after the lidocaine administration, with 1 case degenerating into ventricular fibrillation and cardiac arrest. NEW OR UNIQUE INFORMATION PROVIDED Arrhythmias associated with lidocaine should be considered when treating dogs with supraventricular tachyarrhythmia.
Collapse
Affiliation(s)
- Joonbum Seo
- Animal Referral Centre, Auckland, New Zealand.,School of Veterinary Science, Massey University, Palmerston North, New Zealand.,Department of Clinical Science and Services, Royal Veterinary College, Hatfield, UK
| | | | | | | | - Erica Tinson
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield, UK
| | - David J Connolly
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield, UK
| |
Collapse
|
21
|
Kay AR, Eberl DF, Wang JW. Myogenic contraction of a somatic muscle powers rhythmic flow of hemolymph through Drosophila antennae and generates brain pulsations. J Exp Biol 2021; 224:jeb242699. [PMID: 34585241 PMCID: PMC8545754 DOI: 10.1242/jeb.242699] [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: 04/23/2021] [Accepted: 09/22/2021] [Indexed: 11/20/2022]
Abstract
Hemolymph is driven through the antennae of Drosophila melanogaster by the rhythmic contraction of muscle 16 (m16), which runs through the brain. Contraction of m16 results in the expansion of an elastic ampulla, opening ostia and filling the ampulla. Relaxation of the ampullary membrane forces hemolymph through vessels into the antennae. We show that m16 is an auto-active rhythmic somatic muscle. The activity of m16 leads to the rapid perfusion of the antenna by hemolymph. In addition, it leads to the rhythmic agitation of the brain, which could be important for clearing the interstitial space.
Collapse
Affiliation(s)
- Alan R. Kay
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Daniel F. Eberl
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Jing W. Wang
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, CA 92093, USA
| |
Collapse
|
22
|
Wolf V, Kühnel A, Teckentrup V, Koenig J, Kroemer NB. Does transcutaneous auricular vagus nerve stimulation affect vagally mediated heart rate variability? A living and interactive Bayesian meta-analysis. Psychophysiology 2021; 58:e13933. [PMID: 34473846 DOI: 10.1111/psyp.13933] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 12/29/2022]
Abstract
Non-invasive brain stimulation techniques, such as transcutaneous auricular vagus nerve stimulation (taVNS), have considerable potential for clinical use. Beneficial effects of taVNS have been demonstrated on symptoms in patients with mental or neurological disorders as well as transdiagnostic dimensions, including mood and motivation. However, since taVNS research is still an emerging field, the underlying neurophysiological processes are not yet fully understood, and the replicability of findings on biomarkers of taVNS effects has been questioned. The objective of this analysis was to synthesize the current evidence concerning the effects of taVNS on vagally mediated heart rate variability (vmHRV), a candidate biomarker that has, so far, received most attention in the field. We performed a living Bayesian random effects meta-analysis. To keep the synthesis of evidence transparent and up to date as new studies are being published, we developed a Shiny web app that regularly incorporates new results and enables users to modify study selection criteria to evaluate the robustness of the inference across potential confounds. Our analysis focuses on 16 single-blind studies comparing taVNS versus sham in healthy participants. The meta-analysis provides strong evidence for the null hypothesis (g = 0.014, CIshortest = [-0.103, 0.132], BF01 = 24.678), indicating that acute taVNS does not alter vmHRV compared to sham. To conclude, there is no support for the hypothesis that vmHRV is a robust biomarker for acute taVNS. By increasing transparency and timeliness, the concept of living meta-analyses can lead to transformational benefits in emerging fields such as non-invasive brain stimulation.
Collapse
Affiliation(s)
- Vinzent Wolf
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health (TüCMH), University of Tübingen, Tübingen, Germany.,Department of Psychology, University of Salzburg, Salzburg, Austria
| | - Anne Kühnel
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health (TüCMH), University of Tübingen, Tübingen, Germany.,Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry and International Max Planck Research School for Translational Psychiatry (IMPRS-TP), Munich, Germany
| | - Vanessa Teckentrup
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health (TüCMH), University of Tübingen, Tübingen, Germany
| | - Julian Koenig
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Nils B Kroemer
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health (TüCMH), University of Tübingen, Tübingen, Germany
| |
Collapse
|
23
|
Iwasaki YK. Simple LA Surgical Ablation or Perfect Biatrial Surgical Ablation: Eternal Theme? JACC. ASIA 2021; 1:215-217. [PMID: 36338155 PMCID: PMC9627903 DOI: 10.1016/j.jacasi.2021.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Affiliation(s)
- Yu-ki Iwasaki
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| |
Collapse
|
24
|
Scalco A, Moro N, Mongillo M, Zaglia T. Neurohumoral Cardiac Regulation: Optogenetics Gets Into the Groove. Front Physiol 2021; 12:726895. [PMID: 34531763 PMCID: PMC8438220 DOI: 10.3389/fphys.2021.726895] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/27/2021] [Indexed: 12/25/2022] Open
Abstract
The cardiac autonomic nervous system (ANS) is the main modulator of heart function, adapting contraction force, and rate to the continuous variations of intrinsic and extrinsic environmental conditions. While the parasympathetic branch dominates during rest-and-digest sympathetic neuron (SN) activation ensures the rapid, efficient, and repeatable increase of heart performance, e.g., during the "fight-or-flight response." Although the key role of the nervous system in cardiac homeostasis was evident to the eyes of physiologists and cardiologists, the degree of cardiac innervation, and the complexity of its circuits has remained underestimated for too long. In addition, the mechanisms allowing elevated efficiency and precision of neurogenic control of heart function have somehow lingered in the dark. This can be ascribed to the absence of methods adequate to study complex cardiac electric circuits in the unceasingly moving heart. An increasing number of studies adds to the scenario the evidence of an intracardiac neuron system, which, together with the autonomic components, define a little brain inside the heart, in fervent dialogue with the central nervous system (CNS). The advent of optogenetics, allowing control the activity of excitable cells with cell specificity, spatial selectivity, and temporal resolution, has allowed to shed light on basic neuro-cardiology. This review describes how optogenetics, which has extensively been used to interrogate the circuits of the CNS, has been applied to untangle the knots of heart innervation, unveiling the cellular mechanisms of neurogenic control of heart function, in physiology and pathology, as well as those participating to brain-heart communication, back and forth. We discuss existing literature, providing a comprehensive view of the advancement in the understanding of the mechanisms of neurogenic heart control. In addition, we weigh the limits and potential of optogenetics in basic and applied research in neuro-cardiology.
Collapse
Affiliation(s)
- Arianna Scalco
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | - Nicola Moro
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | - Marco Mongillo
- Veneto Institute of Molecular Medicine, Padova, Italy
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Tania Zaglia
- Veneto Institute of Molecular Medicine, Padova, Italy
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| |
Collapse
|
25
|
Abramochkin DV, Kuzmin VS, Matchkov V, Kamensky AA, Wang T. The snake heart pacemaker is localized near the sinoatrial valve. J Exp Biol 2021; 224:271070. [PMID: 34318309 DOI: 10.1242/jeb.242778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/23/2021] [Indexed: 11/20/2022]
Abstract
To provide the first description of the exact location of primary pacemaker of the squamate heart, we used sharp microelectrode impalements and optical mapping of isolated sinus venosus preparations from Burmese pythons. We located the dominant pacemaker site at the base of the right leaflet of the sinoatrial valve (SAV), but latent pacemakers were also identified in a circular region around the SAV. Acetylcholine (10-5 mol l-1) or noradrenaline (10-6 mol l-1) induced shifts of the leading pacemaker site to other points near the SAV. The ionic currents of most of the cardiomyocytes isolated enzymatically from the SAV region resembled those of typical working myocytes from the sinus venosus. However, seven cells lacked the background inward rectifier current (IK1) and had a time-dependent hyperpolarization-induced inward current identified as the 'funny' pacemaker current (If). Therefore, the region proximal to SAV demonstrates pacemaking activity and contains cells that resemble the electrophysiological properties of mammalian pacemaker myocytes.
Collapse
Affiliation(s)
- Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, 119234 Moscow, Russia.,Laboratory of Cardiac Electrophysiology, National Medical Research Center for Cardiology, 3rd Cherepkovskaya, 15a, 121552 Moscow, Russia.,Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova, 1a, 117997 Moscow, Russia
| | - Vladislav S Kuzmin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, 119234 Moscow, Russia.,Laboratory of Cardiac Electrophysiology, National Medical Research Center for Cardiology, 3rd Cherepkovskaya, 15a, 121552 Moscow, Russia.,Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova, 1a, 117997 Moscow, Russia
| | - Vladimir Matchkov
- MEMBRANES, Department of Biomedicine, Faculty of Health, University of Aarhus, 8000 Aarhus, Denmark
| | - Andrey A Kamensky
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, 119234 Moscow, Russia
| | - Tobias Wang
- Section of Zoophysiology, Institute of Biology, University of Aarhus, 8000C Aarhus, Denmark
| |
Collapse
|
26
|
Choi S, Baudot M, Vivas O, Moreno CM. Slowing down as we age: aging of the cardiac pacemaker's neural control. GeroScience 2021; 44:1-17. [PMID: 34292477 PMCID: PMC8811107 DOI: 10.1007/s11357-021-00420-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 07/07/2021] [Indexed: 12/19/2022] Open
Abstract
The cardiac pacemaker ignites and coordinates the contraction of the whole heart, uninterruptedly, throughout our entire life. Pacemaker rate is constantly tuned by the autonomous nervous system to maintain body homeostasis. Sympathetic and parasympathetic terminals act over the pacemaker cells as the accelerator and the brake pedals, increasing or reducing the firing rate of pacemaker cells to match physiological demands. Despite the remarkable reliability of this tissue, the pacemaker is not exempt from the detrimental effects of aging. Mammals experience a natural and continuous decrease in the pacemaker rate throughout the entire lifespan. Why the pacemaker rhythm slows with age is poorly understood. Neural control of the pacemaker is remodeled from birth to adulthood, with strong evidence of age-related dysfunction that leads to a downshift of the pacemaker. Such evidence includes remodeling of pacemaker tissue architecture, alterations in the innervation, changes in the sympathetic acceleration and the parasympathetic deceleration, and alterations in the responsiveness of pacemaker cells to adrenergic and cholinergic modulation. In this review, we revisit the main evidence on the neural control of the pacemaker at the tissue and cellular level and the effects of aging on shaping this neural control.
Collapse
Affiliation(s)
- Sabrina Choi
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, 98195, USA
| | - Matthias Baudot
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, 98195, USA
| | - Oscar Vivas
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, 98195, USA
| | - Claudia M Moreno
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, 98195, USA.
| |
Collapse
|
27
|
Mantri S, Wu SM, Goodyer WR. Molecular Profiling of the Cardiac Conduction System: the Dawn of a New Era. Curr Cardiol Rep 2021; 23:103. [PMID: 34196831 DOI: 10.1007/s11886-021-01536-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/17/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE OF REVIEW Recent technological advances have led to an increased ability to define the gene expression profile of the cardiac conduction system (CCS). Here, we review the most salient studies to emerge in recent years and discuss existing gaps in our knowledge as well as future areas of investigation. RECENT FINDINGS Molecular profiling of the CCS spans several decades. However, the advent of high-throughput sequencing strategies has allowed for the discovery of unique transcriptional programs of the many diverse CCS cell types. The CCS, a diverse structure with significant inter- and intra-component cellular heterogeneity, is essential to the normal function of the heart. Progress in transcriptomic profiling has improved the resolution and depth of characterization of these unique and clinically relevant CCS cell types. Future studies leveraging this big data will play a crucial role in improving our understanding of CCS development and function as well as translating these findings into tangible translational tools for the improved detection, prevention, and treatment of cardiac arrhythmias.
Collapse
Affiliation(s)
- Sruthi Mantri
- Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Sean M Wu
- Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, 94305, USA.,Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Stanford, CA, 94305, USA.,Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - William R Goodyer
- Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, 94305, USA. .,Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Stanford, CA, 94305, USA. .,Division of Pediatric Cardiology, Electrophysiology, Department of Pediatrics, Lucile Packard Children's Hospital, Stanford University School of Medicine, Room G1105 Lokey Stem Cell Research Building, 265 Campus Drive, Stanford, CA, 94305, USA.
| |
Collapse
|
28
|
Chang W, Li G. Clinical review of sick sinus syndrome and atrial fibrillation. Herz 2021; 47:244-250. [PMID: 34156514 DOI: 10.1007/s00059-021-05046-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 04/29/2021] [Accepted: 05/06/2021] [Indexed: 12/25/2022]
Abstract
Sick sinus syndrome (SSS) is a set of diseases with abnormal cardiac pacing, which manifests as diverse cardiac arrhythmias, especially bradycardia. The clinical presentation is inconspicuous in the early stage, but with the progression of this disease, patients may present with symptoms and signs of end-organ hypoperfusion. As a common result in the natural history of the disease, SSS coexisting with atrial fibrillation (AF) forms the basis of bradycardia-tachycardia syndrome. Age-related interstitial fibrosis is considered to be the common pathophysiological mechanism between SSS and AF. The combination of these diseases will adversely affect the condition of patients and the efficiency of subsequent treatment. Although the exact mechanism is not clear to date, the extensive structural and electrical remodeling of the atrium are considered to be the important mechanism for the occurrence of AF in patients with SSS. Pacemaker implantation is the first-line treatment for symptomatic patients with SSS and documented bradycardia history. In view of the adverse effects of AF on the treatment of SSS, researchers have focused on evaluating different pacing modes and algorithms to reduce the risk of AF during pacing. Catheter ablation may also be used as an alternative second-line therapy for some patients with SSS and AF.
Collapse
Affiliation(s)
- Wenxing Chang
- Department of Ultrasound, the Second Affiliated Hospital of Dalian Medical University, 116027, Dalian, China
| | - Guangsen Li
- Department of Ultrasound, the Second Affiliated Hospital of Dalian Medical University, 116027, Dalian, China.
| |
Collapse
|
29
|
Hennis K, Rötzer RD, Piantoni C, Biel M, Wahl-Schott C, Fenske S. Speeding Up the Heart? Traditional and New Perspectives on HCN4 Function. Front Physiol 2021; 12:669029. [PMID: 34122140 PMCID: PMC8191466 DOI: 10.3389/fphys.2021.669029] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/19/2021] [Indexed: 01/20/2023] Open
Abstract
The sinoatrial node (SAN) is the primary pacemaker of the heart and is responsible for generating the intrinsic heartbeat. Within the SAN, spontaneously active pacemaker cells initiate the electrical activity that causes the contraction of all cardiomyocytes. The firing rate of pacemaker cells depends on the slow diastolic depolarization (SDD) and determines the intrinsic heart rate (HR). To adapt cardiac output to varying physical demands, HR is regulated by the autonomic nervous system (ANS). The sympathetic and parasympathetic branches of the ANS innervate the SAN and regulate the firing rate of pacemaker cells by accelerating or decelerating SDD-a process well-known as the chronotropic effect. Although this process is of fundamental physiological relevance, it is still incompletely understood how it is mediated at the subcellular level. Over the past 20 years, most of the work to resolve the underlying cellular mechanisms has made use of genetically engineered mouse models. In this review, we focus on the findings from these mouse studies regarding the cellular mechanisms involved in the generation and regulation of the heartbeat, with particular focus on the highly debated role of the hyperpolarization-activated cyclic nucleotide-gated cation channel HCN4 in mediating the chronotropic effect. By focusing on experimental data obtained in mice and humans, but not in other species, we outline how findings obtained in mice relate to human physiology and pathophysiology and provide specific information on how dysfunction or loss of HCN4 channels leads to human SAN disease.
Collapse
Affiliation(s)
- Konstantin Hennis
- Center for Drug Research, Department of Pharmacy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - René D. Rötzer
- Center for Drug Research, Department of Pharmacy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Chiara Piantoni
- Institute for Neurophysiology, Hannover Medical School, Hanover, Germany
| | - Martin Biel
- Center for Drug Research, Department of Pharmacy, Ludwig-Maximilians-Universität München, Munich, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| | - Christian Wahl-Schott
- Institute for Neurophysiology, Hannover Medical School, Hanover, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| | - Stefanie Fenske
- Center for Drug Research, Department of Pharmacy, Ludwig-Maximilians-Universität München, Munich, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| |
Collapse
|
30
|
Morotti S, Ni H, Peters CH, Rickert C, Asgari-Targhi A, Sato D, Glukhov AV, Proenza C, Grandi E. Intracellular Na + Modulates Pacemaking Activity in Murine Sinoatrial Node Myocytes: An In Silico Analysis. Int J Mol Sci 2021; 22:5645. [PMID: 34073281 PMCID: PMC8198068 DOI: 10.3390/ijms22115645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 12/19/2022] Open
Abstract
Background: The mechanisms underlying dysfunction in the sinoatrial node (SAN), the heart's primary pacemaker, are incompletely understood. Electrical and Ca2+-handling remodeling have been implicated in SAN dysfunction associated with heart failure, aging, and diabetes. Cardiomyocyte [Na+]i is also elevated in these diseases, where it contributes to arrhythmogenesis. Here, we sought to investigate the largely unexplored role of Na+ homeostasis in SAN pacemaking and test whether [Na+]i dysregulation may contribute to SAN dysfunction. Methods: We developed a dataset-specific computational model of the murine SAN myocyte and simulated alterations in the major processes of Na+ entry (Na+/Ca2+ exchanger, NCX) and removal (Na+/K+ ATPase, NKA). Results: We found that changes in intracellular Na+ homeostatic processes dynamically regulate SAN electrophysiology. Mild reductions in NKA and NCX function increase myocyte firing rate, whereas a stronger reduction causes bursting activity and loss of automaticity. These pathologic phenotypes mimic those observed experimentally in NCX- and ankyrin-B-deficient mice due to altered feedback between the Ca2+ and membrane potential clocks underlying SAN firing. Conclusions: Our study generates new testable predictions and insight linking Na+ homeostasis to Ca2+ handling and membrane potential dynamics in SAN myocytes that may advance our understanding of SAN (dys)function.
Collapse
Affiliation(s)
- Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
| | - Colin H. Peters
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (C.H.P.); (C.R.); (C.P.)
| | - Christian Rickert
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (C.H.P.); (C.R.); (C.P.)
| | - Ameneh Asgari-Targhi
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
| | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
| | - Alexey V. Glukhov
- Department of Medicine, Cardiovascular Medicine, University of Wisconsin Madison School of Medicine and Public Health, Madison, WI 53705, USA;
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (C.H.P.); (C.R.); (C.P.)
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA; (H.N.); (A.A.-T.); (D.S.)
| |
Collapse
|
31
|
Assembly of the Cardiac Pacemaking Complex: Electrogenic Principles of Sinoatrial Node Morphogenesis. J Cardiovasc Dev Dis 2021; 8:jcdd8040040. [PMID: 33917972 PMCID: PMC8068396 DOI: 10.3390/jcdd8040040] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/31/2021] [Accepted: 04/05/2021] [Indexed: 11/24/2022] Open
Abstract
Cardiac pacemaker cells located in the sinoatrial node initiate the electrical impulses that drive rhythmic contraction of the heart. The sinoatrial node accounts for only a small proportion of the total mass of the heart yet must produce a stimulus of sufficient strength to stimulate the entire volume of downstream cardiac tissue. This requires balancing a delicate set of electrical interactions both within the sinoatrial node and with the downstream working myocardium. Understanding the fundamental features of these interactions is critical for defining vulnerabilities that arise in human arrhythmic disease and may provide insight towards the design and implementation of the next generation of potential cellular-based cardiac therapeutics. Here, we discuss physiological conditions that influence electrical impulse generation and propagation in the sinoatrial node and describe developmental events that construct the tissue-level architecture that appears necessary for sinoatrial node function.
Collapse
|
32
|
Prokhorov MD, Karavaev AS, Ishbulatov YM, Ponomarenko VI, Kiselev AR, Kurths J. Interbeat interval variability versus frequency modulation of heart rate. Phys Rev E 2021; 103:042404. [PMID: 34005986 DOI: 10.1103/physreve.103.042404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/23/2021] [Indexed: 01/15/2023]
Abstract
The heart rate in humans is regulated by the autonomic nervous system, which modulates the frequency of heart contractions, resulting in heart rate variability (HRV). Therefore, to assess the activity of the autonomic nervous system, which contains important information for medical diagnostics, methods based on the analysis of interbeat interval variability are often used. This approach does not require the use of invasive methods for measuring the signals of the autonomic nervous system, but its accuracy is an open question. Using mathematical modeling, we investigate the possibility of extracting the signal of frequency modulation of the heartbeats from the electrocardiogram (ECG) signal and conduct a detailed comparison of the extracted signal with the real modulating signal. Since the quality of extraction of the signal of frequency modulation from the ECG depends on the method of demodulation, we compare two different approaches. One is based on the detection of the main oscillation rhythm and its bandpass filtering, and the other on the heterodyning technique. It is shown that low-frequency (LF) and high-frequency (HF) oscillations in HRV associated, respectively, with sympathetic and parasympathetic modulation by the autonomic nervous system, in the general case, significantly differ from the signals of frequency modulation of the heart rate in shape, but have close similarity with them in the frequency domain. We find that in model systems, the similarity of the LF component of HRV with sympathetic modulation of the heart rate is higher than the similarity of the HF component of HRV with parasympathetic modulation.
Collapse
Affiliation(s)
- M D Prokhorov
- Saratov Branch of Kotelnikov Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Zelyonaya Street 38, Saratov 410019, Russia
| | - A S Karavaev
- Saratov Branch of Kotelnikov Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Zelyonaya Street 38, Saratov 410019, Russia
- Saratov State University, Astrakhanskaya Street 83, Saratov 410012, Russia
- Institute of Cardiological Research, Saratov State Medical University, Saratov, B. Kazachaya Street, 112, Saratov 410012, Russia
| | - Y M Ishbulatov
- Saratov Branch of Kotelnikov Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Zelyonaya Street 38, Saratov 410019, Russia
- Saratov State University, Astrakhanskaya Street 83, Saratov 410012, Russia
- Institute of Cardiological Research, Saratov State Medical University, Saratov, B. Kazachaya Street, 112, Saratov 410012, Russia
| | - V I Ponomarenko
- Saratov Branch of Kotelnikov Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Zelyonaya Street 38, Saratov 410019, Russia
- Saratov State University, Astrakhanskaya Street 83, Saratov 410012, Russia
| | - A R Kiselev
- Saratov State University, Astrakhanskaya Street 83, Saratov 410012, Russia
- Institute of Cardiological Research, Saratov State Medical University, Saratov, B. Kazachaya Street, 112, Saratov 410012, Russia
| | - J Kurths
- Saratov State University, Astrakhanskaya Street 83, Saratov 410012, Russia
- Physics Department, Humboldt University, Newtonstrasse 15, 12489 Berlin, Germany
- Potsdam Institute for Climate Impact Research, Telegrafenberg A31, 14473 Potsdam, Germany
| |
Collapse
|
33
|
Soattin L, Borbas Z, Caldwell J, Prendergast B, Vohra A, Saeed Y, Hoschtitzky A, Yanni J, Atkinson A, Logantha SJ, Borbas B, Garratt C, Morris GM, Dobrzynski H. Structural and Functional Properties of Subsidiary Atrial Pacemakers in a Goat Model of Sinus Node Disease. Front Physiol 2021; 12:592229. [PMID: 33746765 PMCID: PMC7969524 DOI: 10.3389/fphys.2021.592229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 01/18/2021] [Indexed: 12/19/2022] Open
Abstract
Background The sinoatrial/sinus node (SAN) is the primary pacemaker of the heart. In humans, SAN is surrounded by the paranodal area (PNA). Although the PNA function remains debated, it is thought to act as a subsidiary atrial pacemaker (SAP) tissue and become the dominant pacemaker in the setting of sinus node disease (SND). Large animal models of SND allow characterization of SAP, which might be a target for novel treatment strategies for SAN diseases. Methods A goat model of SND was developed (n = 10) by epicardially ablating the SAN and validated by mapping of emergent SAP locations through an ablation catheter and surface electrocardiogram (ECG). Structural characterization of the goat SAN and SAP was assessed by histology and immunofluorescence techniques. Results When the SAN was ablated, SAPs featured a shortened atrioventricular conduction, consistent with the location in proximity of atrioventricular junction. SAP recovery time showed significant prolongation compared to the SAN recovery time, followed by a decrease over a follow-up of 4 weeks. Like the SAN tissue, the SAP expressed the main isoform of pacemaker hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) and Na+/Ca2+ exchanger 1 (NCX1) and no high conductance connexin 43 (Cx43). Structural characterization of the right atrium (RA) revealed that the SAN was located at the earliest activation [i.e., at the junction of the superior vena cava (SVC) with the RA] and was surrounded by the paranodal-like tissue, extending down to the inferior vena cava (IVC). Emerged SAPs were localized close to the IVC and within the thick band of the atrial muscle known as the crista terminalis (CT). Conclusions SAN ablation resulted in the generation of chronic SAP activity in 60% of treated animals. SAP displayed development over time and was located within the previously discovered PNA in humans, suggesting its role as dominant pacemaker in SND. Therefore, SAP in goat constitutes a promising stable target for electrophysiological modification to construct a fully functioning pacemaker.
Collapse
Affiliation(s)
- Luca Soattin
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Zoltan Borbas
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
| | - Jane Caldwell
- Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Hull University Teaching Hospitals, Hull, United Kingdom.,Hull York Medical School, Hull, United Kingdom
| | - Brian Prendergast
- Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Akbar Vohra
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Yawer Saeed
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Department of Medicine, Aga Khan University, Karachi, Pakistan
| | - Andreas Hoschtitzky
- Adult Congenital Heart Disease Unit, Manchester Royal Infirmary, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Royal Brompton Hospital, London, United Kingdom.,Imperial College London, London, United Kingdom
| | - Joseph Yanni
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Andrew Atkinson
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Sunil Jit Logantha
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Liverpool Centre for Cardiovascular Sciences, Department of Cardiovascular and Metabolic Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Balint Borbas
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Clifford Garratt
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Gwilym Matthew Morris
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Halina Dobrzynski
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Department of Anatomy, Jagiellonian University, Krakow, Poland
| |
Collapse
|
34
|
Liang D, Xue J, Geng L, Zhou L, Lv B, Zeng Q, Xiong K, Zhou H, Xie D, Zhang F, Liu J, Liu Y, Li L, Yang J, Xue Z, Chen YH. Cellular and molecular landscape of mammalian sinoatrial node revealed by single-cell RNA sequencing. Nat Commun 2021; 12:287. [PMID: 33436583 PMCID: PMC7804277 DOI: 10.1038/s41467-020-20448-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/03/2020] [Indexed: 02/07/2023] Open
Abstract
Bioelectrical impulses intrinsically generated within the sinoatrial node (SAN) trigger the contraction of the heart in mammals. Though discovered over a century ago, the molecular and cellular features of the SAN that underpin its critical function in the heart are uncharted territory. Here, we identify four distinct transcriptional clusters by single-cell RNA sequencing in the mouse SAN. Functional analysis of differentially expressed genes identifies a core cell cluster enriched in the electrogenic genes. The similar cellular features are also observed in the SAN from both rabbit and cynomolgus monkey. Notably, Vsnl1, a core cell cluster marker in mouse, is abundantly expressed in SAN, but is barely detectable in atrium or ventricle, suggesting that Vsnl1 is a potential SAN marker. Importantly, deficiency of Vsnl1 not only reduces the beating rate of human induced pluripotent stem cell - derived cardiomyocytes (hiPSC-CMs) but also the heart rate of mice. Furthermore, weighted gene co-expression network analysis (WGCNA) unveiled the core gene regulation network governing the function of the SAN in mice. Overall, these findings reveal the whole transcriptome profiling of the SAN at single-cell resolution, representing an advance toward understanding of both the biology and the pathology of SAN. The spontaneous bioelectrical activity of pacemaker cells in sinoatrial node (SAN) triggers the heartbeats. Here, the authors perform single-cell RNA sequencing in the mouse SAN and identify molecular and cellular features of the SAN conserved in rabbit and cynomolgus monkey, identifying a new potential SAN marker.
Collapse
Affiliation(s)
- Dandan Liang
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China
| | - Jinfeng Xue
- Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, 200092, China
| | - Li Geng
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China
| | - Liping Zhou
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China
| | - Bo Lv
- Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, 200092, China
| | - Qiao Zeng
- Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, 200092, China
| | - Ke Xiong
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China
| | - Huixing Zhou
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China
| | - Duanyang Xie
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China
| | - Fulei Zhang
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China
| | - Jie Liu
- Translational Center of Stem Cell Research, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China
| | - Yi Liu
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China
| | - Li Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, 200092, China
| | - Jian Yang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, 200092, China
| | - Zhigang Xue
- Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, 200092, China. .,Reproductive Medicine Center, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China.
| | - Yi-Han Chen
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China. .,Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China. .,Institute of Medical Genetics, Tongji University, Shanghai, 200092, China. .,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, 200092, China.
| |
Collapse
|
35
|
Mesirca P, Fedorov VV, Hund TJ, Torrente AG, Bidaud I, Mohler PJ, Mangoni ME. Pharmacologic Approach to Sinoatrial Node Dysfunction. Annu Rev Pharmacol Toxicol 2021; 61:757-778. [PMID: 33017571 PMCID: PMC7790915 DOI: 10.1146/annurev-pharmtox-031120-115815] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The spontaneous activity of the sinoatrial node initiates the heartbeat. Sino-atrial node dysfunction (SND) and sick sinoatrial (sick sinus) syndrome are caused by the heart's inability to generate a normal sinoatrial node action potential. In clinical practice, SND is generally considered an age-related pathology, secondary to degenerative fibrosis of the heart pacemaker tissue. However, other forms of SND exist, including idiopathic primary SND, which is genetic, and forms that are secondary to cardiovascular or systemic disease. The incidence of SND in the general population is expected to increase over the next half century, boosting the need to implant electronic pacemakers. During the last two decades, our knowledge of sino-atrial node physiology and of the pathophysiological mechanisms underlying SND has advanced considerably. This review summarizes the current knowledge about SND mechanisms and discusses the possibility of introducing new pharmacologic therapies for treating SND.
Collapse
Affiliation(s)
- Pietro Mesirca
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France;
- LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| | - Vadim V Fedorov
- Frick Center for Heart Failure and Arrhythmia at the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Wexner Medical Center, Columbus, Ohio 43210, USA
| | - Thomas J Hund
- Frick Center for Heart Failure and Arrhythmia at the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210, USA
| | - Angelo G Torrente
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France;
- LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| | - Isabelle Bidaud
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France;
- LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| | - Peter J Mohler
- Frick Center for Heart Failure and Arrhythmia at the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Wexner Medical Center, Columbus, Ohio 43210, USA
- Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Matteo E Mangoni
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France;
- LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| |
Collapse
|
36
|
Çinier G, Haseeb S, Bazoukis G, Yeung C, Gül EE. Evaluation and Management of Asymptomatic Bradyarrhythmias. Curr Cardiol Rev 2021; 17:60-67. [PMID: 32693770 PMCID: PMC8142361 DOI: 10.2174/1573403x16666200721154143] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/30/2020] [Accepted: 06/15/2020] [Indexed: 12/26/2022] Open
Abstract
Asymptomatic bradyarrhythmias involving sinus node dysfunction and atrioventicular blocks are frequently noted in clinical practice. Its prevalence is expected to rise as devices that are developed for monitoring cardiac rhythm for longer duration become more widely available. Episodes of bradyarrhythmia that are asymptomatic are considered to have a benign course compared with those that cause symptoms and do not necessitate further treatment. However, in certain cases, they can be a harbinger of future symptoms or cardiac manifestations of systemic diseases. The evaluation and risk stratification of individuals presenting with asymptomatic bradyarrhythmias is important not only for preventing implantation of unnecessary permanent pacing devices but also for reducing significant morbidity by implementing proper treatment as required. In this article, we will review the current evidence on the pathophysiology, diagnosis, evaluation and management of patients with asymptomatic bradyarrhythmias.
Collapse
Affiliation(s)
- Göksel Çinier
- Department of Cardiology, Kaçkar State Hospital, Rize, Turkey
| | - Sohaib Haseeb
- Department of Cardiology, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Giorgos Bazoukis
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Cynthia Yeung
- Department of Cardiology, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - E. Elvin Gül
- Division of Cardiac Electrophysiology, Madinah Cardiac Centre, Medina, Saudi Arabia
| |
Collapse
|
37
|
da Silva RM, de Souza Maciel A. Conduction Disorders: The Value of Surface ECG. Curr Cardiol Rev 2021; 17:173-181. [PMID: 32392118 PMCID: PMC8226204 DOI: 10.2174/1573403x16666200511090151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/03/2020] [Accepted: 04/09/2020] [Indexed: 02/08/2023] Open
Abstract
PURPOSE OF REVIEW The purpose of the current mini-review is to describe the importance of surface ECG for the diagnosis of conduction disorder. METHODS The MEDLINE/PubMed database was used, with the keywords "ECG" and "conduction disorders"; over the past 10 years. Other documents were included because of their relevance. MAIN FINDINGS Data on the anatomy and function of the cardiac electrical system have been described. Conduction disorders including sinus node dysfunction, atrioventricular blocks, intraventricular conduction disorders are exposed as to their epidemiology, etiology, presentation, anatomical site of impaired conduction of the electrical stimulus. The importance of ECG in patients with a cardiac implantable electronic device was also discussed, in addition to future perspectives. CONCLUSION Surface ECG allows the diagnosis of atrioventricular and intraventricular conduction disorder and its anatomical block site most of the time, without the need for invasive tests such as electrophysiological study. Dysfunctions of cardiac implantable electronic devices can be diagnosed by ECG, as well as the prediction of response to cardiac resynchronization therapy.
Collapse
Affiliation(s)
- Rose M.F.L. da Silva
- Department of Internal Medicine, Faculty of Medicine, University of Minas Gerais, Hospital das Clínicas, Federal, Belo Horizonte/Minas Gerais, Brazil
| | - Alessandra de Souza Maciel
- Department of Internal Medicine, Faculty of Medicine, University of Minas Gerais, Hospital das Clínicas, Federal, Belo Horizonte/Minas Gerais, Brazil
| |
Collapse
|
38
|
Brennan JA, Chen Q, Gams A, Dyavanapalli J, Mendelowitz D, Peng W, Efimov IR. Evidence of Superior and Inferior Sinoatrial Nodes in the Mammalian Heart. JACC Clin Electrophysiol 2020; 6:1827-1840. [PMID: 33357580 PMCID: PMC7770336 DOI: 10.1016/j.jacep.2020.09.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 12/25/2022]
Abstract
OBJECTIVES This study sought to investigate the shift of leading pacemaker locations in healthy and failing mammalian hearts over the entire range of physiological heart rates (HRs), and to molecularly characterize spatial regions of spontaneous activity. BACKGROUND A normal heartbeat originates as an action potential in a group of pacemaker cells known as the sinoatrial node (SAN), located near the superior vena cava. HRs and the anatomical site of origin of pacemaker activity in the adult heart are known to dynamically change in response to various physiological inputs, yet the mechanism of this pacemaker shift is not well understood. METHODS Optical mapping was applied to ex vivo rat and human isolated right atrial tissues, and HRs were modulated with acetylcholine and isoproterenol. RNA sequencing was performed on tissue areas that elicited spontaneous activity, and comparisons were made to neighboring myocardial tissues. RESULTS Functional and molecular evidence identified and confirmed the presence of 2 competing right atrial pacemakers localized near the superior vena cava and the inferior vena cava—the superior SAN (sSAN) and inferior SAN (iSAN), respectively—which preferentially control the fast and slow HRs. Both of these regions were evident in non-failing rat and human hearts and maintained spontaneous activity in the rat heart when physically separated from one another. Molecular analysis of these 2 pacemaker regions revealed unique but similar transcriptional profiles, suggesting iSAN dominance when the sSAN is silent. CONCLUSIONS The presence of 2 spatially distinct dominant pacemakers, sSAN and iSAN, in the mammalian heart clarifies previous identification of migrating pacemakers and corresponding changes in P-wave morphology in mammalian species.
Collapse
Affiliation(s)
- Jaclyn A Brennan
- Department of Biomedical Engineering, George Washington University School of Engineering and Applied Sciences, Washington, DC, USA
| | - Qing Chen
- Department of Physics, George Washington University Columbian College of Art and Sciences, Washington, DC, USA
| | - Anna Gams
- Department of Biomedical Engineering, George Washington University School of Engineering and Applied Sciences, Washington, DC, USA
| | - Jhansi Dyavanapalli
- Department of Pharmacology and Physiology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - David Mendelowitz
- Department of Pharmacology and Physiology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Weiqun Peng
- Department of Physics, George Washington University Columbian College of Art and Sciences, Washington, DC, USA
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University School of Engineering and Applied Sciences, Washington, DC, USA.
| |
Collapse
|
39
|
Hayashi K, Teramoto R, Nomura A, Asano Y, Beerens M, Kurata Y, Kobayashi I, Fujino N, Furusho H, Sakata K, Onoue K, Chiang DY, Kiviniemi TO, Buys E, Sips P, Burch ML, Zhao Y, Kelly AE, Namura M, Kita Y, Tsuchiya T, Kaku B, Oe K, Takeda Y, Konno T, Inoue M, Fujita T, Kato T, Funada A, Tada H, Hodatsu A, Nakanishi C, Sakamoto Y, Tsuda T, Nagata Y, Tanaka Y, Okada H, Usuda K, Cui S, Saito Y, MacRae CA, Takashima S, Yamagishi M, Kawashiri MA, Takamura M. Impact of functional studies on exome sequence variant interpretation in early-onset cardiac conduction system diseases. Cardiovasc Res 2020; 116:2116-2130. [PMID: 31977013 DOI: 10.1093/cvr/cvaa010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 10/02/2019] [Accepted: 01/17/2020] [Indexed: 12/20/2022] Open
Abstract
AIMS The genetic cause of cardiac conduction system disease (CCSD) has not been fully elucidated. Whole-exome sequencing (WES) can detect various genetic variants; however, the identification of pathogenic variants remains a challenge. We aimed to identify pathogenic or likely pathogenic variants in CCSD patients by using WES and 2015 American College of Medical Genetics and Genomics (ACMG) standards and guidelines as well as evaluating the usefulness of functional studies for determining them. METHODS AND RESULTS We performed WES of 23 probands diagnosed with early-onset (<65 years) CCSD and analysed 117 genes linked to arrhythmogenic diseases or cardiomyopathies. We focused on rare variants (minor allele frequency < 0.1%) that were absent from population databases. Five probands had protein truncating variants in EMD and LMNA which were classified as 'pathogenic' by 2015 ACMG standards and guidelines. To evaluate the functional changes brought about by these variants, we generated a knock-out zebrafish with CRISPR-mediated insertions or deletions of the EMD or LMNA homologs in zebrafish. The mean heart rate and conduction velocities in the CRISPR/Cas9-injected embryos and F2 generation embryos with homozygous deletions were significantly decreased. Twenty-one variants of uncertain significance were identified in 11 probands. Cellular electrophysiological study and in vivo zebrafish cardiac assay showed that two variants in KCNH2 and SCN5A, four variants in SCN10A, and one variant in MYH6 damaged each gene, which resulted in the change of the clinical significance of them from 'Uncertain significance' to 'Likely pathogenic' in six probands. CONCLUSION Of 23 CCSD probands, we successfully identified pathogenic or likely pathogenic variants in 11 probands (48%). Functional analyses of a cellular electrophysiological study and in vivo zebrafish cardiac assay might be useful for determining the pathogenicity of rare variants in patients with CCSD. SCN10A may be one of the major genes responsible for CCSD.
Collapse
Affiliation(s)
- Kenshi Hayashi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Ryota Teramoto
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.,Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Akihiro Nomura
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Yoshihiro Asano
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Manu Beerens
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Yasutaka Kurata
- Department of Physiology, Kanazawa Medical University, Uchinada, Japan
| | - Isao Kobayashi
- Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Noboru Fujino
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Hiroshi Furusho
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Kenji Sakata
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Kenji Onoue
- Cardiovascular Medicine, Nara Medical University, Kashihara, Japan
| | - David Y Chiang
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Tuomas O Kiviniemi
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Eva Buys
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Patrick Sips
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.,Center for Medical Genetics Ghent, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Micah L Burch
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Yanbin Zhao
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Amy E Kelly
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Masanobu Namura
- Department of Cardiology, Kanazawa Cardiovascular Hospital, Kanazawa, Japan
| | - Yoshihito Kita
- Department of Internal Medicine, Wajima Municipal Hospital, Wajima, Japan
| | - Taketsugu Tsuchiya
- Trans-catheter Cardiovascular Therapeutics, Kanazawa Medical University, Uchinada, Japan
| | - Bunji Kaku
- Division of Cardiovascular Medicine, Toyama Red Cross Hospital, Toyama, Japan
| | - Kotaro Oe
- Division of Internal Medicine, Saiseikai Kanazawa Hospital, Kanazawa, Japan
| | - Yuko Takeda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Tetsuo Konno
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Masaru Inoue
- Department of Cardiology, Ishikawa Prefectural Central Hospital, Kanazawa, Japan
| | - Takashi Fujita
- Division of Cardiology, Kouseiren Takaoka Hospital, Takaoka, Japan
| | - Takeshi Kato
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Akira Funada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Hayato Tada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Akihiko Hodatsu
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Chiaki Nakanishi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | | | - Toyonobu Tsuda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Yoji Nagata
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Yoshihiro Tanaka
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Hirofumi Okada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Keisuke Usuda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Shihe Cui
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Yoshihiko Saito
- Cardiovascular Medicine, Nara Medical University, Kashihara, Japan
| | - Calum A MacRae
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Seiji Takashima
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masakazu Yamagishi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.,Osaka University of Human Sciences, Settu, Japan
| | - Masa-Aki Kawashiri
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Masayuki Takamura
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| |
Collapse
|
40
|
Lensen IS, Monfredi OJ, Andris RT, Lake DE, Moorman JR. Heart rate fragmentation gives novel insights into non-autonomic mechanisms governing beat-to-beat control of the heart's rhythm. JRSM Cardiovasc Dis 2020; 9:2048004020948732. [PMID: 32922768 PMCID: PMC7457638 DOI: 10.1177/2048004020948732] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 12/17/2022] Open
Abstract
To demonstrate how heart rate fragmentation gives novel insights into
non-autonomic mechanisms of beat-to-beat variability in cycle length, and
predicts survival of cardiology clinic patients, over and above traditional
clinical risk factors and measures of heart rate variability. Approach: We studied 2893 patients seen by cardiologists with
clinical data including 24-hour Holter monitoring. Novel measures of heart
rate fragmentation alongside canonical time and frequency domain measures of
heart rate variability, as well as an existing local dynamics score were
calculated. A proportional hazards model was utilized to relate the results
to survival. Main results: The novel heart rate fragmentation measures were
validated and characterized with respect to the effects of age, ectopy and
atrial fibrillation. Correlations between parameters were determined.
Critically, heart rate fragmentation results could not be accounted for by
undersampling respiratory sinus arrhythmia. Increased heart rate
fragmentation was associated with poorer survival (p ≪ 0.01 in the
univariate model). In multivariable analyses, increased heart rate
fragmentation and more abnormal local dynamics (p 0.045), along with
increased clinical risk factors (age (p ≪ 0.01), tobacco use (p ≪ 0.01) and
history of heart failure (p 0.019)) and lower low- to high-frequency ratio
(p 0.022) were all independent predictors of 2-year mortality. Significance: Analysis of continuous ECG data with heart rate
fragmentation indices yields information regarding non-autonomic control of
beat-to-beat variability in cycle length that is independent of and additive
to established parameters for investigating heart rate variability, and
predicts mortality in concert with measures of local dynamics, frequency
content of heart rate, and clinical risk factors.
Collapse
Affiliation(s)
- Irene S Lensen
- University of Technology Eindhoven, Noord-Brabant, Netherlands
| | | | | | | | | |
Collapse
|
41
|
Njegic A, Wilson C, Cartwright EJ. Targeting Ca 2 + Handling Proteins for the Treatment of Heart Failure and Arrhythmias. Front Physiol 2020; 11:1068. [PMID: 33013458 PMCID: PMC7498719 DOI: 10.3389/fphys.2020.01068] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/04/2020] [Indexed: 12/18/2022] Open
Abstract
Diseases of the heart, such as heart failure and cardiac arrhythmias, are a growing socio-economic burden. Calcium (Ca2+) dysregulation is key hallmark of the failing myocardium and has long been touted as a potential therapeutic target in the treatment of a variety of cardiovascular diseases (CVD). In the heart, Ca2+ is essential for maintaining normal cardiac function through the generation of the cardiac action potential and its involvement in excitation contraction coupling. As such, the proteins which regulate Ca2+ cycling and signaling play a vital role in maintaining Ca2+ homeostasis. Changes to the expression levels and function of Ca2+-channels, pumps and associated intracellular handling proteins contribute to altered Ca2+ homeostasis in CVD. The remodeling of Ca2+-handling proteins therefore results in impaired Ca2+ cycling, Ca2+ leak from the sarcoplasmic reticulum and reduced Ca2+ clearance, all of which contributes to increased intracellular Ca2+. Currently, approved treatments for targeting Ca2+ handling dysfunction in CVD are focused on Ca2+ channel blockers. However, whilst Ca2+ channel blockers have been successful in the treatment of some arrhythmic disorders, they are not universally prescribed to heart failure patients owing to their ability to depress cardiac function. Despite the progress in CVD treatments, there remains a clear need for novel therapeutic approaches which are able to reverse pathophysiology associated with heart failure and arrhythmias. Given that heart failure and cardiac arrhythmias are closely associated with altered Ca2+ homeostasis, this review will address the molecular changes to proteins associated with both Ca2+-handling and -signaling; their potential as novel therapeutic targets will be discussed in the context of pre-clinical and, where available, clinical data.
Collapse
Affiliation(s)
- Alexandra Njegic
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom.,Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Claire Wilson
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom.,Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Elizabeth J Cartwright
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom
| |
Collapse
|
42
|
Vornanen M. Feeling the heat: source–sink mismatch as a mechanism underlying the failure of thermal tolerance. J Exp Biol 2020; 223:223/16/jeb225680. [DOI: 10.1242/jeb.225680] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
ABSTRACT
A mechanistic explanation for the tolerance limits of animals at high temperatures is still missing, but one potential target for thermal failure is the electrical signaling off cells and tissues. With this in mind, here I review the effects of high temperature on the electrical excitability of heart, muscle and nerves, and refine a hypothesis regarding high temperature-induced failure of electrical excitation and signal transfer [the temperature-dependent deterioration of electrical excitability (TDEE) hypothesis]. A central tenet of the hypothesis is temperature-dependent mismatch between the depolarizing ion current (i.e. source) of the signaling cell and the repolarizing ion current (i.e. sink) of the receiving cell, which prevents the generation of action potentials (APs) in the latter. A source–sink mismatch can develop in heart, muscles and nerves at high temperatures owing to opposite effects of temperature on source and sink currents. AP propagation is more likely to fail at the sites of structural discontinuities, including electrically coupled cells, synapses and branching points of nerves and muscle, which impose an increased demand of inward current. At these sites, temperature-induced source–sink mismatch can reduce AP frequency, resulting in low-pass filtering or a complete block of signal transmission. In principle, this hypothesis can explain a number of heat-induced effects, including reduced heart rate, reduced synaptic transmission between neurons and reduced impulse transfer from neurons to muscles. The hypothesis is equally valid for ectothermic and endothermic animals, and for both aquatic and terrestrial species. Importantly, the hypothesis is strictly mechanistic and lends itself to experimental falsification.
Collapse
Affiliation(s)
- Matti Vornanen
- Department of Environmental and Biological Sciences , University of Eastern Finland, 80101 Joensuu, Finland
| |
Collapse
|
43
|
MacDonald EA, Madl J, Greiner J, Ramadan AF, Wells SM, Torrente AG, Kohl P, Rog-Zielinska EA, Quinn TA. Sinoatrial Node Structure, Mechanics, Electrophysiology and the Chronotropic Response to Stretch in Rabbit and Mouse. Front Physiol 2020; 11:809. [PMID: 32774307 PMCID: PMC7388775 DOI: 10.3389/fphys.2020.00809] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 06/18/2020] [Indexed: 12/12/2022] Open
Abstract
The rhythmic electrical activity of the heart's natural pacemaker, the sinoatrial node (SAN), determines cardiac beating rate (BR). SAN electrical activity is tightly controlled by multiple factors, including tissue stretch, which may contribute to adaptation of BR to changes in venous return. In most animals, including human, there is a robust increase in BR when the SAN is stretched. However, the chronotropic response to sustained stretch differs in mouse SAN, where it causes variable responses, including decreased BR. The reasons for this species difference are unclear. They are thought to relate to dissimilarities in SAN electrophysiology (particularly action potential morphology) between mouse and other species and to how these interact with subcellular stretch-activated mechanisms. Furthermore, species-related differences in structural and mechanical properties of the SAN may influence the chronotropic response to SAN stretch. Here we assess (i) how the BR response to sustained stretch of rabbit and mouse isolated SAN relates to tissue stiffness, (ii) whether structural differences could account for observed differences in BR responsiveness to stretch, and (iii) whether pharmacological modification of mouse SAN electrophysiology alters stretch-induced chronotropy. We found disparities in the relationship between SAN stiffness and the magnitude of the chronotropic response to stretch between rabbit and mouse along with differences in SAN collagen structure, alignment, and changes with stretch. We further observed that pharmacological modification to prolong mouse SAN action potential plateau duration rectified the direction of BR changes during sustained stretch, resulting in a positive chronotropic response akin to that of other species. Overall, our results suggest that structural, mechanical, and background electrophysiological properties of the SAN influence the chronotropic response to stretch. Improved insight into the biophysical determinants of stretch effects on SAN pacemaking is essential for a comprehensive understanding of SAN regulation with important implications for studies of SAN physiology and its dysfunction, such as in the aging and fibrotic heart.
Collapse
Affiliation(s)
- Eilidh A MacDonald
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Josef Madl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Joachim Greiner
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ahmed F Ramadan
- Department of Electrical and Computer Engineering, Dalhousie University, Halifax, NS, Canada
| | - Sarah M Wells
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - Angelo G Torrente
- Department of Physiology, Institut de Génomique Fonctionnelle, Montpellier, France
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Eva A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada.,Department of Electrical and Computer Engineering, Dalhousie University, Halifax, NS, Canada
| |
Collapse
|
44
|
Mavroidis M, Athanasiadis NC, Rigas P, Kostavasili I, Kloukina I, Te Rijdt WP, Kavantzas N, Chaniotis D, van Tintelen JP, Skaliora I, Davos CH. Desmin is essential for the structure and function of the sinoatrial node: implications for increased arrhythmogenesis. Am J Physiol Heart Circ Physiol 2020; 319:H557-H570. [PMID: 32678709 DOI: 10.1152/ajpheart.00594.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Our objective was to investigate the effect of desmin depletion on the structure and function of the sinoatrial pacemaker complex (SANcl) and its implication in arrhythmogenesis. Analysis of mice and humans (SANcl) indicated that the sinoatrial node exhibits high amounts of desmin, desmoplakin, N-cadherin, and β-catenin in structures we call "lateral intercalated disks" connecting myocytes side by side. Examination of the SANcl from an arrhythmogenic cardiomyopathy model, desmin-deficient (Des-/-) mouse, by immunofluorescence, ultrastructural, and Western blot analysis showed that the number of these lateral intercalated disks was diminished. Also, electrophysiological recordings of the isolated compact sinoatrial node revealed increased pacemaker systolic potential and higher diastolic depolarization rate compared with wild-type mice. Prolonged interatrial conduction expressed as a longer P wave duration was also observed in Des-/- mice. Upregulation of mRNA levels of both T-type Ca2+ current channels, Cav3.1 and Cav3.2, in the Des-/- myocardium (1.8- and 2.3-fold, respectively) and a 1.9-fold reduction of funny hyperpolarization-activated cyclic nucleotide-gated K+ channel 1 could underlie these functional differences. To investigate arrhythmogenicity, electrocardiographic analysis of Des-deficient mice revealed a major increase in supraventricular and ventricular ectopic beats compared with wild-type mice. Heart rate variability analysis indicated a sympathetic predominance in Des-/- mice, which may further contribute to arrhythmogenicity. In conclusion, our results indicate that desmin elimination leads to structural and functional abnormalities of the SANcl. These alterations may be enhanced by the sympathetic component of the cardiac autonomic nervous system, which is predominant in the desmin-deficient heart, thus leading to increased arrhythmogenesis.NEW & NOTEWORTHY The sinoatrial node exhibits high amounts of desmin and desmoplakin in structures we call "lateral intercalated disks," connecting side-by-side adjacent cardiomyocytes. These structures are diminished in desmin-deficient mouse models. Misregulation of T-type Ca2+ current and hyperpolarization-activated cyclic nucleotide-gated K+ channel 1 was proved along with prolonged interatrial conduction and cardiac autonomic nervous system dysfunction.
Collapse
Affiliation(s)
- Manolis Mavroidis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Nikolaos C Athanasiadis
- Center of Clinical Research and Experimental Surgery, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Pavlos Rigas
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Ioanna Kostavasili
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Ismini Kloukina
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Wouter P Te Rijdt
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Experimental Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nikolaos Kavantzas
- First Department of Pathology, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitris Chaniotis
- Center of Clinical Research and Experimental Surgery, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - J Peter van Tintelen
- Department of Genetics, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Irini Skaliora
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Constantinos H Davos
- Center of Clinical Research and Experimental Surgery, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| |
Collapse
|
45
|
Domingues M, Brookes VJ, Oliveira P, Mavropoulou A, Willis R. Heart rhythm during episodes of collapse in boxers with frequent or complex ventricular ectopy. J Small Anim Pract 2020; 61:127-136. [PMID: 32017114 DOI: 10.1111/jsap.13105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 11/15/2019] [Accepted: 11/18/2019] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To describe heart rhythm during collapse events in boxer dogs using ambulatory electrocardiogram and determine the predictive value of frequent or complex ventricular ectopy for collapse associated with ventricular tachycardia. MATERIALS AND METHODS A total of 659 ambulatory electrocardiogram recordings from 429 boxer dogs were identified from a database in the UK. Summary statistics described the frequency and complexity of ventricular ectopy during all recordings, recordings in which collapse occurred and associated boxer demographics. Positive predictive values were calculated to investigate whether frequent ventricular ectopy was useful to predict heart rhythm during episodes of collapse. RESULTS Of the 659 ambulatory electrocardiogram recordings, 250 recordings showed <50 single ventricular beats (Group 1), and frequent (≥50) or complex ventricular ectopy were observed in 409 recordings (Group 2). A total of 90 collapse events were observed in 72 ambulatory electrocardiograms from 68 dogs, comprising 30 dogs in Group 1 and 38 dogs in Group 2. In both groups, sinus rhythm was the most frequent collapse rhythm, followed by neurally mediated collapse and then ventricular tachycardia. The proportion of dogs that displayed ventricular tachycardia-associated episodic collapse given that they had frequent (≥50) or complex ventricular ectopy in the study population was 0.11 [95% confidence interval = 0.01 to 0.21]. CLINICAL SIGNIFICANCE These results challenge the preconception that UK boxer dogs with collapse will have ventricular tachycardia and, consequently, the authors recommend definitive diagnosis of the cause of episodic collapse to guide selection of therapeutic drugs.
Collapse
Affiliation(s)
- M Domingues
- Dick White Referrals, Cambridge, CB8 0UH, UK
| | - V J Brookes
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga, Wagga, 2650, Australia
| | - P Oliveira
- Davies Veterinary Speclialists, Manor Farm Business Park, Hitchin, UK
| | - A Mavropoulou
- Davies Veterinary Speclialists, Manor Farm Business Park, Hitchin, UK
| | - R Willis
- Dick White Referrals, Cambridge, CB8 0UH, UK
| |
Collapse
|
46
|
Shah RL, Badhwar N. Approach to narrow complex tachycardia: non-invasive guide to interpretation and management. BRITISH HEART JOURNAL 2020; 106:772-783. [DOI: 10.1136/heartjnl-2019-315304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
47
|
Kirschner Peretz N, Segal S, Yaniv Y. May the Force Not Be With You During Culture: Eliminating Mechano-Associated Feedback During Culture Preserves Cultured Atrial and Pacemaker Cell Functions. Front Physiol 2020; 11:163. [PMID: 32265724 PMCID: PMC7100534 DOI: 10.3389/fphys.2020.00163] [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] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/12/2020] [Indexed: 01/24/2023] Open
Abstract
Cultured cardiomyocytes have been shown to possess significant potential as a model for characterization of mechano-Ca2+, mechano-electric, and mechano-metabolic feedbacks in the heart. However, the majority of cultured cardiomyocytes exhibit impaired electrical, mechanical, biochemical, and metabolic functions. More specifically, the cells do not beat spontaneously (pacemaker cells) or beat at a rate far lower than their physiological counterparts and self-oscillate (atrial and ventricular cells) in culture. Thus, efforts are being invested in ensuring that cultured cardiomyocytes maintain the shape and function of freshly isolated cells. Elimination of contraction during culture has been shown to preserve the mechano-Ca2+, mechano-electric, and mechano-metabolic feedback loops of cultured cells. This review focuses on pacemaker cells, which reside in the sinoatrial node (SAN) and generate regular heartbeat through the initiation of the heart’s electrical, metabolic, and biochemical activities. In parallel, it places emphasis on atrial cells, which are responsible for bridging the electrical conductance from the SAN to the ventricle. The review provides a summary of the main mechanisms responsible for mechano-electrical, Ca2+, and metabolic feedback in pacemaker and atrial cells and of culture methods existing for both cell types. The work concludes with an explanation of how the elimination of mechano-electrical, mechano-Ca2+, and mechano-metabolic feedbacks during culture results in sustained cultured cell function.
Collapse
Affiliation(s)
- Noa Kirschner Peretz
- Biomedical Engineering Faculty, Technion Israel Institute of Technology, Haifa, Israel
| | - Sofia Segal
- Biomedical Engineering Faculty, Technion Israel Institute of Technology, Haifa, Israel
| | - Yael Yaniv
- Biomedical Engineering Faculty, Technion Israel Institute of Technology, Haifa, Israel
| |
Collapse
|
48
|
He Z. The control mechanisms of heart rate dynamics in a new heart rate nonlinear time series model. Sci Rep 2020; 10:4814. [PMID: 32179768 PMCID: PMC7075874 DOI: 10.1038/s41598-020-61562-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/21/2020] [Indexed: 12/19/2022] Open
Abstract
The control mechanisms and implications of heart rate variability (HRV) under the sympathetic (SNS) and parasympathetic nervous system (PNS) modulation remain poorly understood. Here, we establish the HR model/HRV responder using a nonlinear process derived from Newton's second law in stochastic self-restoring systems through dynamic analysis of physiological properties. We conduct model validation by testing, predictions, simulations, and sensitivity and time-scale analysis. We confirm that the outputs of the HRV responder can be accepted as the real data-generating process. Empirical studies show that the dynamic control mechanism of heart rate is a stable fixed point, rather than a strange attractor or transitions between a fixed point and a limit cycle; HR slope (amplitude) may depend on the ratio of cardiac disturbance or metabolic demand mean (standard deviation) to myocardial electrical resistance (PNS-SNS activity). For example, when metabolic demands remain unchanged, HR amplitude depends on PNS to SNS activity; when autonomic activity remains unchanged, HR amplitude during resting reflects basal metabolism. HR parameter alterations suggest that age-related decreased HRV, ultrareduced HRV in heart failure, and ultraelevated HRV in ST segment alterations refer to age-related decreased basal metabolism, impaired myocardial metabolism, and SNS hyperactivity triggered by myocardial ischemia, respectively.
Collapse
Affiliation(s)
- Zonglu He
- Faculty of Management and Economics, Kaetsu University, 2-8-4 Minami-cho, Hanakoganei, Kodaira-shi, Tokyo, 187-8578, Japan.
| |
Collapse
|
49
|
Abstract
A progressive decline in maximum heart rate (mHR) is a fundamental aspect of aging in humans and other mammals. This decrease in mHR is independent of gender, fitness, and lifestyle, affecting in equal measure women and men, athletes and couch potatoes, spinach eaters and fast food enthusiasts. Importantly, the decline in mHR is the major determinant of the age-dependent decline in aerobic capacity that ultimately limits functional independence for many older individuals. The gradual reduction in mHR with age reflects a slowing of the intrinsic pacemaker activity of the sinoatrial node of the heart, which results from electrical remodeling of individual pacemaker cells along with structural remodeling and a blunted β-adrenergic response. In this review, we summarize current evidence about the tissue, cellular, and molecular mechanisms that underlie the reduction in pacemaker activity with age and highlight key areas for future work.
Collapse
Affiliation(s)
- Colin H Peters
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA; , ,
| | - Emily J Sharpe
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA; , ,
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA; , ,
- Department of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| |
Collapse
|
50
|
Pérez-Riera AR, Barbosa-Barros R, Daminello-Raimundo R, de Abreu LC, Nikus K. Current aspects of the basic concepts of the electrophysiology of the sinoatrial node. J Electrocardiol 2019; 57:112-118. [DOI: 10.1016/j.jelectrocard.2019.08.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/16/2019] [Accepted: 08/19/2019] [Indexed: 12/14/2022]
|