1
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Li T, Marashly Q, Kim JA, Li N, Chelu MG. Cardiac conduction diseases: understanding the molecular mechanisms to uncover targets for future treatments. Expert Opin Ther Targets 2024; 28:385-400. [PMID: 38700451 DOI: 10.1080/14728222.2024.2351501] [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: 11/18/2023] [Accepted: 05/01/2024] [Indexed: 05/05/2024]
Abstract
INTRODUCTION The cardiac conduction system (CCS) is crucial for maintaining adequate cardiac frequency at rest and modulation during exercise. Furthermore, the atrioventricular node and His-Purkinje system are essential for maintaining atrioventricular and interventricular synchrony and consequently maintaining an adequate cardiac output. AREAS COVERED In this review article, we examine the anatomy, physiology, and pathophysiology of the CCS. We then discuss in detail the most common genetic mutations and the molecular mechanisms of cardiac conduction disease (CCD) and provide our perspectives on future research and therapeutic opportunities in this field. EXPERT OPINION Significant advancement has been made in understanding the molecular mechanisms of CCD, including the recognition of the heterogeneous signaling at the subcellular levels of sinoatrial node, the involvement of inflammatory and autoimmune mechanisms, and the potential impact of epigenetic regulations on CCD. However, the current treatment of CCD manifested as bradycardia still relies primarily on cardiovascular implantable electronic devices (CIEDs). On the other hand, an If specific inhibitor was developed to treat inappropriate sinus tachycardia and sinus tachycardia in heart failure patients with reduced ejection fraction. More work is needed to translate current knowledge into pharmacologic or genetic interventions for the management of CCDs.
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Affiliation(s)
- Tingting Li
- Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX, USA
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Qussay Marashly
- Department of Cardiology, Montefiore Medical Center, New York, NY, USA
| | - Jitae A Kim
- Division of CardiovasculMedicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Na Li
- Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX, USA
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Mihail G Chelu
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
- Department of Medicine (Division of Cardiology), Baylor College of Medicine, Houston, TX, USA
- Division of Cardiology, Baylor St. Luke's Medical Center, Houston, TX, USA
- Division of Cardiology, Texas Heart Institute, Houston, TX, USA
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2
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Owusu-Mensah A, Treat J, Bernardi J, Pfeiffer R, Goodrow R, Tsevi B, Lam V, Audette M, Cordeiro JM, Deo M. Identification and characterization of two novel KCNH2 mutations contributing to long QT syndrome. PLoS One 2024; 19:e0287206. [PMID: 38181028 PMCID: PMC10769013 DOI: 10.1371/journal.pone.0287206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 05/31/2023] [Indexed: 01/07/2024] Open
Abstract
We identified two different inherited mutations in KCNH2 gene, or human ether-a-go-go related gene (hERG), which are linked to Long QT Syndrome. The first mutation was in a 1-day-old infant, whereas the second was in a 14-year-old girl. The two KCNH2 mutations were transiently transfected into either human embryonic kidney (HEK) cells or human induced pluripotent stem-cell derived cardiomyocytes. We performed associated multiscale computer simulations to elucidate the arrhythmogenic potentials of the KCNH2 mutations. Genetic screening of the first and second index patients revealed a heterozygous missense mutation in KCNH2, resulting in an amino acid change (P632L) in the outer loop of the channel and substitution at position 428 from serine to proline (S428P), respectively. Heterologous expression of P632L and S428P into HEK cells produced no hERG current compared to the wild type (WT). Moreover, the co-transfection of WT and P632L yielded no hERG current; however, the co-transfection of WT and S428P yielded partial hERG current. Action potentials were prolonged in a complete or partial blockade of hERG current from computer simulations which was more severe in Purkinje than ventricular myocytes. Three dimensional simulations revealed a higher susceptibility to reentry in the presence of hERG current blockade. Our experimental findings suggest that both P632L and S428P mutations may impair the KCNH2 gene. The Purkinje cells exhibit a more severe phenotype than ventricular myocytes, and the hERG current blockade renders the ventricles an arrhythmogenic substrate from computer modeling.
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Affiliation(s)
- Anthony Owusu-Mensah
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia, United States of America
| | - Jacqueline Treat
- Masonic Medical Research Laboratory, Utica, New York, United States of America
| | - Joyce Bernardi
- Masonic Medical Research Laboratory, Utica, New York, United States of America
| | - Ryan Pfeiffer
- Masonic Medical Research Laboratory, Utica, New York, United States of America
| | - Robert Goodrow
- Masonic Medical Research Laboratory, Utica, New York, United States of America
| | - Bright Tsevi
- Department of Engineering, Norfolk State University, Norfolk, Virginia, United States of America
| | - Victoria Lam
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia, United States of America
| | - Michel Audette
- Department of Computational Modeling and Simulation Engineering, Old Dominion University, Norfolk, Virginia, United States of America
| | - Jonathan M. Cordeiro
- Masonic Medical Research Laboratory, Utica, New York, United States of America
- ICON Laboratory Services Incorporation, Whitesboro, New York, United States of America
| | - Makarand Deo
- Department of Engineering, Norfolk State University, Norfolk, Virginia, United States of America
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3
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Chakraborty P, Azam MA, Massé S, Lai PF, Rose RA, Ibarra Moreno CA, Riazi S, Nanthakumar K. Uncoupling cytosolic calcium from membrane voltage by transient receptor potential melastatin 4 channel (TRPM4) modulation: A novel strategy to treat ventricular arrhythmias. Heart Rhythm O2 2023; 4:725-732. [PMID: 38034891 PMCID: PMC10685170 DOI: 10.1016/j.hroo.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023] Open
Abstract
The current antiarrhythmic paradigm is mainly centered around modulating membrane voltage. However, abnormal cytosolic calcium (Ca2+) signaling, which plays an important role in driving membrane voltage, has not been targeted for therapeutic purposes in arrhythmogenesis. There is clear evidence for bidirectional coupling between membrane voltage and intracellular Ca2+. Cytosolic Ca2+ regulates membrane voltage through Ca2+-sensitive membrane currents. As a component of Ca2+-sensitive currents, Ca2+-activated nonspecific cationic current through the TRPM4 (transient receptor potential melastatin 4) channel plays a significant role in Ca2+-driven changes in membrane electrophysiology. In myopathic and ischemic ventricles, upregulation and/or enhanced activity of this current is associated with the generation of afterdepolarization (both early and delayed), reduction of repolarization reserve, and increased propensity to ventricular arrhythmias. In this review, we describe a novel concept for the management of ventricular arrhythmias in the remodeled ventricle based on mechanistic concepts from experimental studies, by uncoupling the Ca2+-induced changes in membrane voltage by inhibition of this TRPM4-mediated current.
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Affiliation(s)
- Praloy Chakraborty
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Mohammed Ali Azam
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Stéphane Massé
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Patrick F.H. Lai
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Robert A. Rose
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Carlos A. Ibarra Moreno
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology and Pain Medicine, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Sheila Riazi
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology and Pain Medicine, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Kumaraswamy Nanthakumar
- Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
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4
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Burunkaya DK, Ozeke O, Korkmaz A, Ozcan F, Kara M, Ozcan Cetin EH, Yaman M, Demirhan C, Tuncez A, Dogan U, Yontar OC, Cay S, Aras D, Topaloglu S. The Initial Part of Polymorphic Ventricular Tachycardia as a Clue for the Sustainability of Tachycardia and Ablation Success: A Varying Degree of Purkinje-Myocardial Complicity? J Innov Card Rhythm Manag 2023; 14:5472-5480. [PMID: 37388422 PMCID: PMC10306249 DOI: 10.19102/icrm.2023.14066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 09/26/2022] [Indexed: 07/01/2023] Open
Abstract
The cardiac Purkinje system is capable of very rapid burst activity suggestive of its potential role in being a driver of polymorphic ventricular tachycardia (VT) (PMVT) or ventricular fibrillation (VF). It plays a pivotal role, however, not only in the triggering of but also the perpetuation of ventricular arrhythmias. A varying degree of Purkinje-myocardial complicity has been blamed in determining not only the sustained or non-sustained nature of PMVT but also the pleomorphism of the non-sustained runs. The initial part of PMVT before cascading to the whole ventricle to establish disorganized VF can give important clues for ablation of PMVT and VF. We present a case of an electrical storm after acute myocardial infarction that was successfully ablated after identifying Purkinje potentials that triggered polymorphic, monomorphic, and pleiomorphic VTs and VF.
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Affiliation(s)
| | - Ozcan Ozeke
- Department of Cardiology, University of Health Sciences, Ankara City Hospital, Ankara, Turkey
| | - Ahmet Korkmaz
- Department of Cardiology, University of Health Sciences, Ankara City Hospital, Ankara, Turkey
| | - Firat Ozcan
- Department of Cardiology, University of Health Sciences, Ankara City Hospital, Ankara, Turkey
| | - Meryem Kara
- Department of Cardiology, University of Health Sciences, Ankara City Hospital, Ankara, Turkey
| | - Elif Hande Ozcan Cetin
- Department of Cardiology, University of Health Sciences, Ankara City Hospital, Ankara, Turkey
| | - Mehmet Yaman
- Department of Cardiology, Eregli Echomar Hospital, Zonguldak, Turkey
| | - Can Demirhan
- Department of Cardiology, University of Health Sciences, Ankara City Hospital, Ankara, Turkey
| | | | - Umuttan Dogan
- Department of Cardiology, Akdeniz University, Antalya, Turkey
| | - Osman Can Yontar
- Department of Cardiology, University of Health Sciences, Samsun Education and Research Hospital, Samsun, Turkey
| | - Serkan Cay
- Department of Cardiology, University of Health Sciences, Ankara City Hospital, Ankara, Turkey
| | - Dursun Aras
- Department of Cardiology, Istanbul Medipol University, Istanbul, Turkey
| | - Serkan Topaloglu
- Department of Cardiology, University of Health Sciences, Ankara City Hospital, Ankara, Turkey
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5
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John RM, Willner J. Proarrhythmic effect of radiofrequency catheter ablation on the right ventricular moderator band. J Arrhythm 2022; 38:813-816. [PMID: 36237867 PMCID: PMC9535760 DOI: 10.1002/joa3.12752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/17/2022] [Accepted: 06/29/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Roy M. John
- Stanford School of Medicine Stanford University Palo Alto California USA
| | - Jonathan Willner
- Department of Cardiology Northshore University Hospital Manhasset New York USA
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6
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Ullah A, Hoang-Trong MT, Lederer WJ, Winslow RL, Jafri MS. Critical Requirements for the Initiation of a Cardiac Arrhythmia in Rat Ventricle: How Many Myocytes? Cells 2022; 11:cells11121878. [PMID: 35741007 PMCID: PMC9221049 DOI: 10.3390/cells11121878] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
Cardiovascular disease is the leading cause of death worldwide due in a large part to arrhythmia. In order to understand how calcium dynamics play a role in arrhythmogenesis, normal and dysfunctional Ca2+ signaling in a subcellular, cellular, and tissued level is examined using cardiac ventricular myocytes at a high temporal and spatial resolution using multiscale computational modeling. Ca2+ sparks underlie normal excitation-contraction coupling. However, under pathological conditions, Ca2+ sparks can combine to form Ca2+ waves. These propagating elevations of (Ca2+)i can activate an inward Na+-Ca2+ exchanger current (INCX) that contributes to early after-depolarization (EADs) and delayed after-depolarizations (DADs). However, how cellular currents lead to full depolarization of the myocardium and how they initiate extra systoles is still not fully understood. This study explores how many myocytes must be entrained to initiate arrhythmogenic depolarizations in biophysically detailed computational models. The model presented here suggests that only a small number of myocytes must activate in order to trigger an arrhythmogenic propagating action potential. These conditions were examined in 1-D, 2-D, and 3-D considering heart geometry. The depolarization of only a few hundred ventricular myocytes is required to trigger an ectopic depolarization. The number decreases under disease conditions such as heart failure. Furthermore, in geometrically restricted parts of the heart such as the thin muscle strands found in the trabeculae and papillary muscle, the number of cells needed to trigger a propagating depolarization falls even further to less than ten myocytes.
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Affiliation(s)
- Aman Ullah
- School of Systems Biology, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA; (A.U.); (M.T.H.-T.)
| | - Minh Tuan Hoang-Trong
- School of Systems Biology, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA; (A.U.); (M.T.H.-T.)
| | - William Jonathan Lederer
- Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Raimond L. Winslow
- Institute for Computational Medicine and Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD 20218, USA;
- The Roux Institute, Northeastern University, Portland, ME 04102, USA
| | - Mohsin Saleet Jafri
- School of Systems Biology, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA; (A.U.); (M.T.H.-T.)
- Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
- Institute for Computational Medicine and Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD 20218, USA;
- Correspondence: ; Tel.: +1-703-993-8420
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7
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The Purkinje network plays a major role in low-energy ventricular defibrillation. Comput Biol Med 2021; 141:105133. [PMID: 34954609 DOI: 10.1016/j.compbiomed.2021.105133] [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: 10/15/2021] [Revised: 12/10/2021] [Accepted: 12/10/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND During ventricular fibrillation (VF), targeting the excitable gap (EG) of reentry throughout the myocardium with low-energy surface stimulation shows promise for painless defibrillation. However, the Purkinje network may provide alternative pathways for reentry to evade termination. This study investigates the role of the Purkinje network in painless defibrillation. METHODS In a computational human biventricular model featuring a Purkinje network, VF was initiated with 4 Hz epicardial pacing. Defibrillation was attempted by stimulating myocardial surface EG with a low-energy 2 ms duration pulse at 2x stimulus capture, which was administered at coupling intervals incremented by 0.25 s between 0.25 and 5 s after VF initiation. Defibrillation was accomplished if reentry ceased ≤ 1 s after the defibrillation pulse. The protocol was repeated with the Purkinje network and myocardial surface EG stimulated simultaneously, and again after uncoupling the Purkinje network from the myocardium. RESULTS VF with the Purkinje network coupled and uncoupled had comparable dominant frequency in the left (3.81 ± 0.44 versus 3.77 ± 0.53 Hz) and right (3.80 ± 0.37 versus 3.76 ± 0.48 Hz) ventricles. When uncoupling the Purkinje network, myocardial surface EG stimulation terminated VF for all defibrillation pulses. When coupled, myocardial EG surface stimulation terminated VF for only 55% of the defibrillation pulses, but improved to 100% when stimulated simultaneously with Purkinje network EG. Defibrillation failures were attributed to EG evading stimulation in the Purkinje network. CONCLUSIONS Defibrillation that exclusively targets myocardium can fail due to accessory pathways in the Purkinje network that allow for reentrant activity to evade termination and maintain VF. Painless defibrillation strategies should be adapted to include the Purkinje network.
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8
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Zhang LY, Dong SJ, Yu HJ, Chu YJ. Ventricular tachycardia originating from the His bundle: A case report. World J Clin Cases 2021; 9:10040-10045. [PMID: 34877348 PMCID: PMC8610906 DOI: 10.12998/wjcc.v9.i32.10040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/16/2021] [Accepted: 09/19/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Ventricular tachycardia (VT) commonly occurs among patients with heart failure and can even cause sudden cardiac death. VT originating from the His bundle branch has been rarely reported. We present the case of a patient with VT from the His bundle branch.
CASE SUMMARY A 58-year-old female complained of paroxysmal palpitations and dizziness for approximately 6 mo. She had a history of fatty liver and cholecystitis, and carotid atherosclerosis could not be excluded from the ultrasound results. An evaluation of the electrocardiogram obtained after admission showed spontaneous conversion between two different morphologies. The possible electrophysiologic mechanism suggested that the dual-source VT originated from the same source, the His bundle branch. Finally, the His bundle branch was ablated, and a dual-chamber pacemaker was inserted into the patient’s heart. No further VT occurred during the 3-year follow-up after hospital discharge.
CONCLUSION The diagnosis of VT originating from the His bundle is rare and difficult to establish. The results of this study showed VT originating from the His bundle based on a careful evaluation of the electrocardiogram, and the diagnosis was confirmed by an intracardiac electrophysiologic examination.
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Affiliation(s)
- Lu-Yao Zhang
- Department of Cardiology, Zhengzhou University People’s Hospital, Zhengzhou 450003, Henan Province, China
| | - Shu-Juan Dong
- Department of Cardiology, Zhengzhou University People’s Hospital, Zhengzhou 450003, Henan Province, China
| | - Hai-Jia Yu
- Department of Emergency, Zhengzhou University People’s Hospital, Zhengzhou 450003, Henan Province, China
| | - Ying-Jie Chu
- Department of Cardiology, Zhengzhou University People’s Hospital, Zhengzhou 450003, Henan Province, China
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9
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Wang J, Xia Y, Lu A, Wang H, Davis DR, Liu P, Beanlands RS, Liang W. Cardiomyocyte-specific deletion of β-catenin protects mouse hearts from ventricular arrhythmias after myocardial infarction. Sci Rep 2021; 11:17722. [PMID: 34489488 PMCID: PMC8421412 DOI: 10.1038/s41598-021-97176-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 08/23/2021] [Indexed: 11/09/2022] Open
Abstract
Wnt/β-catenin signaling is activated in the heart after myocardial infarction (MI). This study aims to investigate if β-catenin deletion affects post-MI ion channel gene alterations and ventricular tachycardias (VT). MI was induced by permanent ligation of left anterior descending artery in wild-type (WT) and cardiomyocyte-specific β-catenin knockout (KO) mice. KO mice showed reduced susceptibility to VT (18% vs. 77% in WT) at 8 weeks after MI, associated with reduced scar size and attenuated chamber dilation. qPCR analyses of both myocardial tissues and purified cardiomyocytes demonstrated upregulation of Wnt pathway genes in border and infarct regions after MI, including Wnt ligands (such as Wnt4) and receptors (such as Fzd1 and Fzd2). At 1 week after MI, cardiac sodium channel gene (Scn5a) transcript was reduced in WT but not in KO hearts, consistent with previous studies showing Scn5a inhibition by Wnt/β-catenin signaling. At 8 weeks after MI when Wnt genes have declined, Scn5a returned to near sham levels and K+ channel gene downregulations were not different between WT and KO mice. This study demonstrated that VT susceptibility in the chronic phase after MI is reduced in mice with cardiomyocyte-specific β-catenin deletion primarily through attenuated structural remodeling, but not ion channel gene alterations.
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Affiliation(s)
- Jerry Wang
- University of Ottawa Heart Institute, 40 Ruskin St, Ottawa, ON, K1Y 4W7, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Ying Xia
- University of Ottawa Heart Institute, 40 Ruskin St, Ottawa, ON, K1Y 4W7, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Aizhu Lu
- University of Ottawa Heart Institute, 40 Ruskin St, Ottawa, ON, K1Y 4W7, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Hongwei Wang
- University of Ottawa Heart Institute, 40 Ruskin St, Ottawa, ON, K1Y 4W7, Canada
| | - Darryl R Davis
- University of Ottawa Heart Institute, 40 Ruskin St, Ottawa, ON, K1Y 4W7, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Peter Liu
- University of Ottawa Heart Institute, 40 Ruskin St, Ottawa, ON, K1Y 4W7, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Rob S Beanlands
- University of Ottawa Heart Institute, 40 Ruskin St, Ottawa, ON, K1Y 4W7, Canada
| | - Wenbin Liang
- University of Ottawa Heart Institute, 40 Ruskin St, Ottawa, ON, K1Y 4W7, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.
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10
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Logantha SJRJ, Cai XJ, Yanni J, Jones CB, Stephenson RS, Stuart L, Quigley G, Monfredi O, Nakao S, Oh IY, Starborg T, Kitmitto A, Vohra A, Hutcheon RC, Corno AF, Jarvis JC, Dobrzynski H, Boyett MR, Hart G. Remodeling of the Purkinje Network in Congestive Heart Failure in the Rabbit. Circ Heart Fail 2021; 14:e007505. [PMID: 34190577 PMCID: PMC8288482 DOI: 10.1161/circheartfailure.120.007505] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Supplemental Digital Content is available in the text. Background: Purkinje fibers (PFs) control timing of ventricular conduction and play a key role in arrhythmogenesis in heart failure (HF) patients. We investigated the effects of HF on PFs. Methods: Echocardiography, electrocardiography, micro-computed tomography, quantitative polymerase chain reaction, immunohistochemistry, volume electron microscopy, and sharp microelectrode electrophysiology were used. Results: Congestive HF was induced in rabbits by left ventricular volume- and pressure-overload producing left ventricular hypertrophy, diminished fractional shortening and ejection fraction, and increased left ventricular dimensions. HF baseline QRS and corrected QT interval were prolonged by 17% and 21% (mean±SEMs: 303±6 ms HF, 249±11 ms control; n=8/7; P=0.0002), suggesting PF dysfunction and impaired ventricular repolarization. Micro-computed tomography imaging showed increased free-running left PF network volume and length in HF. mRNA levels for 40 ion channels, Ca2+-handling proteins, connexins, and proinflammatory and fibrosis markers were assessed: 50% and 35% were dysregulated in left and right PFs respectively, whereas only 12.5% and 7.5% changed in left and right ventricular muscle. Funny channels, Ca2+-channels, and K+-channels were significantly reduced in left PFs. Microelectrode recordings from left PFs revealed more negative resting membrane potential, reduced action potential upstroke velocity, prolonged duration (action potential duration at 90% repolarization: 378±24 ms HF, 249±5 ms control; n=23/38; P<0.0001), and arrhythmic events in HF. Similar electrical remodeling was seen at the left PF-ventricular junction. In the failing left ventricle, upstroke velocity and amplitude were increased, but action potential duration at 90% repolarization was unaffected. Conclusions: Severe volume- followed by pressure-overload causes rapidly progressing HF with extensive remodeling of PFs. The PF network is central to both arrhythmogenesis and contractile dysfunction and the pathological remodeling may increase the risk of fatal arrhythmias in HF patients.
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Affiliation(s)
- Sunil Jit R J Logantha
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Liverpool Centre for Cardiovascular Science and Department of Cardiovascular and Metabolic Medicine (S.J.R.J.L.), University of Liverpool, United Kingdom
| | - Xue J Cai
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Joseph Yanni
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Caroline B Jones
- Alder Hey Children's National Health Service Foundation Trust, Liverpool, United Kingdom (C.B.J.)
| | - Robert S Stephenson
- School of Sport and Exercise Sciences, Liverpool John Moores University, United Kingdom (R.S.S., J.C.J.).,Institute of Clinical Sciences, University of Birmingham, United Kingdom (R.S.S.)
| | - Luke Stuart
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Manchester University NHS Foundation Trust, United Kingdom (L.S.)
| | - Gillian Quigley
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Oliver Monfredi
- Division of Cardiovascular Medicine, University of Virginia, Charlottesville (O.M.).,Laboratory of Cardiovascular Medicine, National Institute on Aging, NIH Biomedical Research Center, Baltimore, MD (O.M.)
| | - Shu Nakao
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Kyoto, Japan (S.N.)
| | - Il-Young Oh
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Department of Internal Medicine, Seoul National University Bundang Hospital, Republic of Korea (I.-Y.O.)
| | - Tobias Starborg
- Wellcome Centre for Cell Matrix Research (T.S.), University of Manchester, United Kingdom
| | - Ashraf Kitmitto
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Akbar Vohra
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Robert C Hutcheon
- Division of Clinical Sciences (R.C.H.), University of Liverpool, United Kingdom
| | - Antonio F Corno
- Memorial Hermann Children's Hospital, University of Texas Health, Houston (A.F.C.)
| | - Jonathan C Jarvis
- School of Sport and Exercise Sciences, Liverpool John Moores University, United Kingdom (R.S.S., J.C.J.)
| | - Halina Dobrzynski
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Department of Anatomy, Jagiellonian University, Medical College, Cracow, Poland (H.D.)
| | - Mark R Boyett
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - George Hart
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
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11
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Gómez-Torres F, Estupiñán HY, Ruíz-Sauri A. Identification to cardiac conduction cells in humans and pigs according to their zonal distribution, using histological, immunohistochemical and morphometric study. Res Vet Sci 2021; 138:137-147. [PMID: 34144281 DOI: 10.1016/j.rvsc.2021.06.008] [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: 01/21/2021] [Revised: 05/23/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
Abstract
Histologically, the cardiac conduction network is formed of electrically isolated subendocardial fibers that comprise specialized cells with fewer myofibrils and mitochondria than cardiomyocytes. Our aim is to uncover regional variations of cardiac conduction fibers through histological and morphometric study in a porcine and human model. We analyzed five male adult human hearts and five male pig hearts. The left ventricles were dissected and sectioned in the axial plane into three parts: basal, middle third and apex regions. Cardiac conduction fibers study was carried out using hematoxylin-eosin and Masson's trichrome staining, and cardiac conduction cells and their junctions were identified using desmin, and a PAS method. Cardiac conduction fibers were difficult to pinpoint in humans, mostly showing a darker color or equal to cardiomyocytes. Cardiac conduction fibers in humans were in the subendocardium and in pigs in the myocardium and subendocardium. Cardiac conduction fibers were located mainly in the septal region in both humans and pigs. In our morphometric analysis, we were able to determine that cardiac conduction cells in humans (18.52 +/- 5.41 μm) and pigs (21.32 +/- 6.45 μm) were large, compared to cardiomyocytes. Conduction fiber-myocardial junctions were present in 10% in humans and 24.2% in pigs. The performance of immunohistochemical methods made it possible to improve the identification of cardiac conduction cells in the species studied. Study of cardiac conduction fibers and cells and their myocardial junctions is vital to gain insight into their normal distribution in the species analyzed, and thus advance the use of pigs in experimental models of the cardiac conduction system in humans.
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Affiliation(s)
- Fabián Gómez-Torres
- Department of Pathology, Faculty of Medicine, Universitat de Valencia, Av. de Blasco Ibáñez, 15, 46010 Valencia, Spain; Department of Basic Sciences, Medicine School, Universidad Industrial de Santander, Cra 32 # 29-31, 68002 Bucaramanga, Colombia.
| | - H Yesid Estupiñán
- Department of Basic Sciences, Medicine School, Universidad Industrial de Santander, Cra 32 # 29-31, 68002 Bucaramanga, Colombia; Department of Laboratory Medicine, Clinical Research Center, Karolinska Institute, Karolinska University Hospital Huddinge, SE-141 86 Huddinge, Sweden.
| | - Amparo Ruíz-Sauri
- Department of Pathology, Faculty of Medicine, Universitat de Valencia, Av. de Blasco Ibáñez, 15, 46010 Valencia, Spain; INCLIVA Biomedical Research Institute, Av. de Blasco Ibáñez, 17, 46010 Valencia, Spain.
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12
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Singleton MJ, Bhave PD, Beaty EH, Bradford NS, Whalen SP. The Storm Before the Calm: Ablation of Premature Ventricular Complex Trigger for Incessant Ventricular Fibrillation. J Innov Card Rhythm Manag 2021; 12:4501-4505. [PMID: 34035982 PMCID: PMC8139305 DOI: 10.19102/icrm.2021.120501] [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: 06/11/2020] [Accepted: 10/07/2020] [Indexed: 11/25/2022] Open
Abstract
Ventricular tachycardia storm is associated with high mortality rates and is often refractory to treatment. Historically, few options for treatment have existed in cases when antiarrhythmic drugs fail. We report the case of a patient with incessant ventricular fibrillation (VF) in the postinfarction period that was triggered by premature ventricular contractions (PVCs) that persisted despite normal electrolytes, exclusion of ongoing ischemia, infusions of antiarrhythmic drugs, general anesthesia, full circulatory support with extracorporeal membranous oxygenation, and cardiac sympathetic denervation. Given that the VF appeared to be triggered consistently by a unifocal, short-coupled PVC (consistent with Purkinje fiber–mediated VF), we performed catheter ablation, after which point, the patient experienced no further PVCs or ventricular arrhythmia. This case serves as a reminder of three key teaching points. First, not all VF is created equal, with some cases being chiefly the result of a vulnerable substrate and others being best accounted for by frequent triggers. Second, examining the available electrocardiographic data and appropriately interpreting them can guide the selection of therapies up to and including catheter ablation for treatment-refractory VF. Third, full circulatory support greatly facilitates successful electroanatomic mapping and catheter ablation of unstable ventricular arrhythmias.
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Affiliation(s)
- Matthew J Singleton
- Section of Cardiology, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Prashant D Bhave
- Section of Cardiology, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Elijah H Beaty
- Section of Cardiology, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Natalie S Bradford
- Section of Cardiology, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - S Patrick Whalen
- Section of Cardiology, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
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13
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Regulation of Cardiac Conduction and Arrhythmias by Ankyrin/Spectrin-Based Macromolecular Complexes. J Cardiovasc Dev Dis 2021; 8:jcdd8050048. [PMID: 33946725 PMCID: PMC8146975 DOI: 10.3390/jcdd8050048] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
The cardiac conduction system is an extended network of excitable tissue tasked with generation and propagation of electrical impulses to signal coordinated contraction of the heart. The fidelity of this system depends on the proper spatio-temporal regulation of ion channels in myocytes throughout the conduction system. Importantly, inherited or acquired defects in a wide class of ion channels has been linked to dysfunction at various stages of the conduction system resulting in life-threatening cardiac arrhythmia. There is growing appreciation of the role that adapter and cytoskeletal proteins play in organizing ion channel macromolecular complexes critical for proper function of the cardiac conduction system. In particular, members of the ankyrin and spectrin families have emerged as important nodes for normal expression and regulation of ion channels in myocytes throughout the conduction system. Human variants impacting ankyrin/spectrin function give rise to a broad constellation of cardiac arrhythmias. Furthermore, chronic neurohumoral and biomechanical stress promotes ankyrin/spectrin loss of function that likely contributes to conduction disturbances in the setting of acquired cardiac disease. Collectively, this review seeks to bring attention to the significance of these cytoskeletal players and emphasize the potential therapeutic role they represent in a myriad of cardiac disease states.
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Morris GM, Ariyaratnam JP. Embryology of the Cardiac Conduction System Relevant to Arrhythmias. Card Electrophysiol Clin 2019; 11:409-420. [PMID: 31400866 DOI: 10.1016/j.ccep.2019.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Embryogenesis of the heart involves the complex cellular differentiation of slow-conducting primary myocardium into the rapidly conducting chamber myocardium of the adult. However, small areas of relatively undifferentiated cells remain to form components of the adult cardiac conduction system (CCS) and nodal tissues. Further investigation has revealed additional areas of nodal-like tissues outside of the established CCS. The embryologic origins of these areas are similar to those of the adult CCS. Under pathologic conditions, these areas can give rise to important clinical arrhythmias. Here, we review the embryologic basis for these proarrhythmic structures within the heart.
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Affiliation(s)
- Gwilym M Morris
- Cardiovascular Sciences, University of Manchester, Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, UK.
| | - Jonathan P Ariyaratnam
- Cardiovascular Sciences, University of Manchester, Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, UK
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