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Tsumoto K, Shimamoto T, Aoji Y, Himeno Y, Kuda Y, Tanida M, Amano A, Kurata Y. Theoretical prediction of early afterdepolarization-evoked triggered activity formation initiating ventricular reentrant arrhythmias. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 240:107722. [PMID: 37515880 DOI: 10.1016/j.cmpb.2023.107722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 07/02/2023] [Accepted: 07/14/2023] [Indexed: 07/31/2023]
Abstract
BACKGROUND AND OBJECTIVE Excessive prolongation of QT interval on ECGs in patients with congenital/acquired long QT syndrome and heart failure is a sign suggesting the development of early afterdepolarization (EAD), an abnormal repolarization in the action potential of ventricular cardiomyocytes. The development of EAD has been believed to be a trigger for fatal tachyarrhythmia, which can be a risk for sudden cardiac death. The role of EAD in triggering ventricular tachycardia (VT) remains unclear. The aim of this study was to elucidate the mechanism of EAD-induced triggered activity formation that leads to the VT such as Torsades de Pointes. METHODS We investigated the relationship between EAD and tachyarrhythmia initiation by constructing homogeneous myocardial sheet models consisting of the mid-myocardial cell version of a human ventricular myocyte model and performing simulations of excitation propagation. RESULTS A solitary island-like (clustering) occurrence of EADs in the homogeneous myocardial sheet could induce a focal excitation wave. However, reentrant excitation, an entity of tachyarrhythmia, was not able to be triggered regardless of the EAD cluster size when the focal excitation wave formed a repolarization potential difference boundary consisting of only a convex surface. The discontinuous distribution of multiple EAD clusters in the ventricular tissue formed a specific repolarization heterogeneity due to the repolarization potential difference, the shape of which depended on EAD cluster size and placed intervals. We found that the triggered activity was formed in such a manner that the repolarization potential difference boundary included a concave surface. CONCLUSIONS The formation of triggered activity that led to tachyarrhythmia required not only the occurrence of EAD onset-mediated focal excitation wave but also a repolarization heterogeneity-based specific repolarization potential difference boundary shape formed within the tissue.
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Affiliation(s)
- Kunichika Tsumoto
- Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan.
| | - Takao Shimamoto
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Kusatsu 525-8577, Japan
| | - Yuma Aoji
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Kusatsu 525-8577, Japan
| | - Yukiko Himeno
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Kusatsu 525-8577, Japan
| | - Yuhichi Kuda
- Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan
| | - Mamoru Tanida
- Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan
| | - Akira Amano
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Kusatsu 525-8577, Japan
| | - Yasutaka Kurata
- Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan.
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Van Den Abeele R, Hendrickx S, Van Nieuwenhuyse E, Dunnink A, Panfilov AV, Vos MA, Wülfers EM, Vandersickel N. Directed graph mapping shows rotors maintain non-terminating and focal sources maintain self-terminating Torsade de Pointes in canine model. Front Physiol 2023; 14:1201260. [PMID: 37565147 PMCID: PMC10411729 DOI: 10.3389/fphys.2023.1201260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/28/2023] [Indexed: 08/12/2023] Open
Abstract
Torsade de Pointes is a polymorphic ventricular tachycardia which is as yet incompletely understood. While the onset of a TdP episode is generally accepted to be caused by triggered activity, the mechanisms for the perpetuation is still under debate. In this study, we analysed data from 54 TdP episodes divided over 5 dogs (4 female, 1 male) with chronic atrioventricular block. Previous research on this dataset showed both reentry and triggered activity to perpetuate the arrhythmia. 13 of those TdP episodes showed reentry as part of the driving mechanism of perpetuating the episode. The remaining 41 episodes were purely ectopic. Reentry was the main mechanism in long-lasting episodes (>14 beats), while focal sources were responsible for maintaining shorter episodes. Building on these results, we re-analysed the data using directed graph mapping This program uses principles from network theory and a combination of positional data and local activation times to identify reentry loops and focal sources within the data. The results of this study are twofold. First, concerning reentry loops, we found that on average non-terminating (NT) episodes (≥10 s) show significantly more simultaneous reentry loops than self-terminating (ST) TdP (<10 s). Non-terminating episodes have on average 2.72 ± 1.48 simultaneous loops, compared to an average of 1.33 ± 0.66 for self-terminating episodes. In addition, each NT episode showed a presence of (bi-)ventricular loops between 10.10% and 69.62% of their total reentry duration. Compared to the ST episodes, only 1 in 4 episodes (25%) showed (bi-)ventricular reentry, lasting only 7.12% of its total reentry duration. This suggests that while focal beats trigger TdP, macro-reentry and multiple simultaneous localized reentries are the major drivers of long-lasting episodes. Second, using heatmaps, we found focal sources to occur in preferred locations, instead of being distributed randomly. This may have implications on treatment if such focal origins can be disabled reliably.
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Affiliation(s)
- Robin Van Den Abeele
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Sander Hendrickx
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Enid Van Nieuwenhuyse
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Albert Dunnink
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Alexander V. Panfilov
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
- Laboratory of Computational Biology and Medicine, Ural Federal University, Yekaterinburg, Russia
- World-Class Research Center “Digital Biodesign and Personalized Healthcare”, Sechenov University, Moscow, Russia
| | - Marc A. Vos
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Eike M. Wülfers
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Nele Vandersickel
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
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Verkerk AO, Wilders R. Human Sinoatrial Node Pacemaker Activity: Role of the Slow Component of the Delayed Rectifier K + Current, I Ks. Int J Mol Sci 2023; 24:7264. [PMID: 37108427 PMCID: PMC10138838 DOI: 10.3390/ijms24087264] [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: 03/22/2023] [Revised: 04/07/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
The pacemaker activity of the sinoatrial node (SAN) has been studied extensively in animal species but is virtually unexplored in humans. Here we assess the role of the slowly activating component of the delayed rectifier K+ current (IKs) in human SAN pacemaker activity and its dependence on heart rate and β-adrenergic stimulation. HEK-293 cells were transiently transfected with wild-type KCNQ1 and KCNE1 cDNA, encoding the α- and β-subunits of the IKs channel, respectively. KCNQ1/KCNE1 currents were recorded both during a traditional voltage clamp and during an action potential (AP) clamp with human SAN-like APs. Forskolin (10 µmol/L) was used to increase the intracellular cAMP level, thus mimicking β-adrenergic stimulation. The experimentally observed effects were evaluated in the Fabbri-Severi computer model of an isolated human SAN cell. Transfected HEK-293 cells displayed large IKs-like outward currents in response to depolarizing voltage clamp steps. Forskolin significantly increased the current density and significantly shifted the half-maximal activation voltage towards more negative potentials. Furthermore, forskolin significantly accelerated activation without affecting the rate of deactivation. During an AP clamp, the KCNQ1/KCNE1 current was substantial during the AP phase, but relatively small during diastolic depolarization. In the presence of forskolin, the KCNQ1/KCNE1 current during both the AP phase and diastolic depolarization increased, resulting in a clearly active KCNQ1/KCNE1 current during diastolic depolarization, particularly at shorter cycle lengths. Computer simulations demonstrated that IKs reduces the intrinsic beating rate through its slowing effect on diastolic depolarization at all levels of autonomic tone and that gain-of-function mutations in KCNQ1 may exert a marked bradycardic effect during vagal tone. In conclusion, IKs is active during human SAN pacemaker activity and has a strong dependence on heart rate and cAMP level, with a prominent role at all levels of autonomic tone.
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Affiliation(s)
- Arie O. Verkerk
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands;
- Department of Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands;
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Wang H, Wu T, Huang Z, Huang J, Geng Z, Cui B, Yan Y, Zhang Y, Wang Y. Channel HCN4 mutation R666Q associated with sporadic arrhythmia decreases channel electrophysiological function and increases protein degradation. J Biol Chem 2022; 298:102599. [PMID: 36244448 PMCID: PMC9663530 DOI: 10.1016/j.jbc.2022.102599] [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: 07/17/2022] [Revised: 10/06/2022] [Accepted: 10/10/2022] [Indexed: 11/07/2022] Open
Abstract
Mutations in the hyperpolarization-activated nucleotide-gated channel 4 (HCN4) are known to be associated with arrhythmias in which QT prolongation (delayed ventricular repolarization) is rare. Here, we identified a HCN4 mutation, HCN4-R666Q, in two sporadic arrhythmia patients with sinus bradycardia, QT prolongation, and short bursts of ventricular tachycardia. To determine the functional effect of the mutation, we conducted clinical, genetic, and functional analyses using whole-cell voltage-clamp, qPCR, Western blot, confocal microscopy, and co-immunoprecipitation. The mean current density of HEK293T cells transfected with HCN4-R666Q was lower in 24 to 36 h after transfection and was much lower in 36 to 48 h after transfection relative to cells transfected with wildtype HCN4. Additionally, we determined that the HCN4-R666Q mutant was more susceptible to ubiquitin-proteasome system–mediated protein degradation than wildtype HCN4. This decreased current density for HCN4-R666Q could be partly rescued by treatment with a proteasome inhibitor. Therefore, we conclude that HCN4-R666Q had an effect on HCN4 function in two aspects, including decreasing the current density of the channel as a biophysical effect and weakening its protein stability. Our findings provide new insights into the pathogenesis of the HCN4-R666Q mutation.
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Tsumoto K, Kurata Y. Bifurcations and Proarrhythmic Behaviors in Cardiac Electrical Excitations. Biomolecules 2022; 12:biom12030459. [PMID: 35327651 PMCID: PMC8946197 DOI: 10.3390/biom12030459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/09/2022] [Accepted: 03/14/2022] [Indexed: 12/23/2022] Open
Abstract
The heart is a hierarchical dynamic system consisting of molecules, cells, and tissues, and acts as a pump for blood circulation. The pumping function depends critically on the preceding electrical activity, and disturbances in the pattern of excitation propagation lead to cardiac arrhythmia and pump failure. Excitation phenomena in cardiomyocytes have been modeled as a nonlinear dynamical system. Because of the nonlinearity of excitation phenomena, the system dynamics could be complex, and various analyses have been performed to understand the complex dynamics. Understanding the mechanisms underlying proarrhythmic responses in the heart is crucial for developing new ways to prevent and control cardiac arrhythmias and resulting contractile dysfunction. When the heart changes to a pathological state over time, the action potential (AP) in cardiomyocytes may also change to a different state in shape and duration, often undergoing a qualitative change in behavior. Such a dynamic change is called bifurcation. In this review, we first summarize the contribution of ion channels and transporters to AP formation and our knowledge of ion-transport molecules, then briefly describe bifurcation theory for nonlinear dynamical systems, and finally detail its recent progress, focusing on the research that attempts to understand the developing mechanisms of abnormal excitations in cardiomyocytes from the perspective of bifurcation phenomena.
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Zahedivash A, Hanisch D, Dubin AM, Trela A, Chubb H, Motonaga KS, Goodyer WR, Maeda K, Reinhartz O, Ma M, Martin E, Ceresnak SR. Implantable Cardioverter Defibrillators in Infants and Toddlers: Indications, Placement, Programming, and Outcomes. Circ Arrhythm Electrophysiol 2022; 15:e010557. [PMID: 35089800 DOI: 10.1161/circep.121.010557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Limited data exist regarding implantable cardioverter defibrillator (ICD) usage in infants and toddlers. This study evaluates ICD placement indications, procedural techniques, programming strategies, and outcomes of ICDs in infants and toddlers. METHODS This is a single-center retrospective review of all patients ≤3 years old who received an ICD from 2009 to 2021. RESULTS Fifteen patients received an ICD at an age of 1.2 years (interquartile range [IQR], 0.1-2.4; 12 [80%] women; weight, 8.2 kg [IQR, 4.2-12.6]) and were followed for a median of 4.28 years (IQR, 1.40-5.53) or 64.2 patient-years. ICDs were placed for secondary prevention in 12 patients (80%). Diagnoses included 8 long-QT syndromes (53%), 4 idiopathic ventricular tachycardias/ventricular fibrillations (VFs; 27%), 1 recurrent ventricular tachycardia with cardiomyopathy (7%), 1 VF with left ventricular noncompaction (7%), and 1 catecholaminergic polymorphic ventricular tachycardia (7%). All implants were epicardial, with a coil in the pericardial space. Intraoperative defibrillation safety testing was attempted in 11 patients (73%), with VF induced in 8 (53%). Successful restoration of sinus rhythm was achieved in all tested patients with a median of 9 (IQR, 7.3-11.3) J or 0.90 (IQR, 0.68-1.04) J/kg. Complications consisted of 1 postoperative chylothorax and 3 episodes of feeding intolerance. VF detection was programmed to 250 (IQR, 240-250) ms with first shock delivering 10 (IQR, 5-15) J or 1.1 (IQR, 0.8-1.4) J/kg. Three patients (20%) received appropriate shocks for ventricular tachycardia/VF. No patient received an inappropriate shock. There were 2 (13%) ventricular lead fractures (at 2.6 and 4.2 years post-implant), 1 (7%) pocket-site infection, and 2 (13%) generator exchanges. All patients were alive, and 1 patient (7%) received a heart transplant. CONCLUSIONS ICDs can be safely and effectively placed for sudden death prevention in infants and toddlers with good midterm outcomes.
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Affiliation(s)
- Aydin Zahedivash
- Department of Pediatrics, Pediatric Cardiology (A.Z., A.M.D., H.C., K.S.M., W.R.G., S.R.C., D.H., A.T.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
| | - Debra Hanisch
- Department of Pediatrics, Pediatric Cardiology (A.Z., A.M.D., H.C., K.S.M., W.R.G., S.R.C., D.H., A.T.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
| | - Anne M Dubin
- Department of Pediatrics, Pediatric Cardiology (A.Z., A.M.D., H.C., K.S.M., W.R.G., S.R.C., D.H., A.T.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
| | - Anthony Trela
- Department of Pediatrics, Pediatric Cardiology (A.Z., A.M.D., H.C., K.S.M., W.R.G., S.R.C., D.H., A.T.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
| | - Henry Chubb
- Department of Pediatrics, Pediatric Cardiology (A.Z., A.M.D., H.C., K.S.M., W.R.G., S.R.C., D.H., A.T.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
| | - Kara S Motonaga
- Department of Pediatrics, Pediatric Cardiology (A.Z., A.M.D., H.C., K.S.M., W.R.G., S.R.C., D.H., A.T.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA.,Department of Cardiothoracic Surgery, Children's Hospital of Philadelphia, University of Pennsylvania (K.S.M.)
| | - William Rowland Goodyer
- Department of Pediatrics, Pediatric Cardiology (A.Z., A.M.D., H.C., K.S.M., W.R.G., S.R.C., D.H., A.T.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
| | | | - Olaf Reinhartz
- Department of Cardiothoracic Surgery (O.R., M.M., E.M.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
| | - Michael Ma
- Department of Cardiothoracic Surgery (O.R., M.M., E.M.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
| | - Elisabeth Martin
- Department of Cardiothoracic Surgery (O.R., M.M., E.M.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
| | - Scott R Ceresnak
- Department of Pediatrics, Pediatric Cardiology (A.Z., A.M.D., H.C., K.S.M., W.R.G., S.R.C., D.H., A.T.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, CA
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Sasai H, Goto H, Kawashiri M, Kuwahara T. Long QT as a first sign for propionic acidemia in a 10-year-old girl. Pediatr Int 2022; 64:e14752. [PMID: 34747083 DOI: 10.1111/ped.14752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 03/09/2021] [Accepted: 04/16/2021] [Indexed: 10/19/2022]
Affiliation(s)
- Hideo Sasai
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan.,Clinical Genetics Center, Gifu University Hospital, Gifu, Japan
| | - Hiroko Goto
- Department of Pediatric Cardiology, Gifu Prefectural General Medical Center, Gifu, Japan
| | - Miwa Kawashiri
- Department of Pediatrics, Japanese Red Cross Takayama Hospital, Takayama, Japan
| | - Takashi Kuwahara
- Department of Pediatric Cardiology, Gifu Prefectural General Medical Center, Gifu, Japan
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Kamga MVK, Reppel M, Hescheler J, Nguemo F. Modeling genetic cardiac channelopathies using induced pluripotent stem cells - Status quo from an electrophysiological perspective. Biochem Pharmacol 2021; 192:114746. [PMID: 34461117 DOI: 10.1016/j.bcp.2021.114746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 12/15/2022]
Abstract
Long QT syndrome (LQTS), Brugada syndrome (BrS), and catecholaminergic polymorphic ventricular tachycardia (CPVT) are genetic diseases of the heart caused by mutations in specific cardiac ion channels and are characterized by paroxysmal arrhythmias, which can deteriorate into ventricular fibrillation. In LQTS3 and BrS different mutations in the SCN5A gene lead to a gain-or a loss-of-function of the voltage-gated sodium channel Nav1.5, respectively. Although sharing the same gene mutation, these syndromes are characterized by different clinical manifestations and functional perturbations and in some cases even present an overlapping clinical phenotype. Several studies have shown that Na+ current abnormalities in LQTS3 and BrS can also cause Ca2+-signaling aberrancies in cardiomyocytes (CMs). Abnormal Ca2+ homeostasis is also the main feature of CPVT which is mostly caused by heterozygous mutations in the RyR2 gene. Large numbers of disease-causing mutations were identified in RyR2 and SCN5A but it is not clear how different variants in the SCN5A gene produce different clinical syndromes and if in CPVT Ca2+ abnormalities and drug sensitivities vary depending on the mutation site in the RyR2. These questions can now be addressed by using patient-specific in vitro models of these diseases based on induced pluripotent stem cells (iPSCs). In this review, we summarize different insights gained from these models with a focus on electrophysiological perturbations caused by different ion channel mutations and discuss how will this knowledge help develop better stratification and more efficient personalized therapies for these patients.
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Affiliation(s)
- Michelle Vanessa Kapchoup Kamga
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Michael Reppel
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany; Praxis für Kardiologie und Angiologie, Landsberg am Lech, Germany
| | - Jürgen Hescheler
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Filomain Nguemo
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
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Warda AEA, Tammam M, El-Gazar RA, Sarhan RM, Gaber S. Hydroxychloroquine and Azithromycin Combination in The Management of COVID-19 Infection: Safety and Effectiveness Challenges. Curr Drug Saf 2021; 17:143-151. [PMID: 34315385 DOI: 10.2174/1574886316666210727152609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 04/15/2021] [Accepted: 04/27/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND The treatment of COVID-19 disease remains a dilemma so far because there is no approved therapy for it. This study aimed to evaluate the use of hydroxychloroquine and azithromycin combination in treatment. OBJECTIVE This study was carried out to determine the safety and effectiveness of hydroxychloroquine and azithromycin combination in COVID 19 patients. METHODS This study included 90 adult COVID 19 patients. Treatment of all patients followed Egyptian Ministry of Health COVID-19 protocols, receiving a combination of hydroxychloroquine 400mg twice on day 1, then 200 mg twice daily in addition to azithromycin 500mg/day for 5 days. ECG findings especially the QTc interval was assessed before and after 5 days from the administration. RESULTS All patients showed a statistically significant higher post-treatment QTc readings (433.6 ± 37.2) compared to baseline QTc (402.4 ± 31.3) at p<0.005 with a median QTc prolongation by 26 mSec and IQR (17.8-41.3), but without serious clinical complications. Only 5.6% of patients showed QTc more than 500 mSec and no torsade de points or cardiac arrest. Geriatric patients were at higher risk for QTc prolongation compared to patients aged less than 65 years but without a significant difference as regards the median max QTc difference p˂0.65. The expected therapeutic effectiveness was 82.5% for moderate patients compared to 26% in severe patients (P<0.005). CONCLUSION In a modest safety profile, we support the evidence that HQ/AZ therapy can be used to treat Covid-19 infection with more effectiveness in moderate rather than severe cases, which might be a reflection to the time of administration in the disease course.
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Affiliation(s)
| | | | - Rabab Ahmed El-Gazar
- Clinical Pharmacy Department, Faculty of Pharmacy, October 6 University, Giza, Egypt
| | - Rania Mohammad Sarhan
- Clinical Pharmacy Department, Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt
| | - Sayed Gaber
- Critical Care Medicine Department, Faculty of Medicine, Cairo University, Giza, Egypt
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Abstract
The physiological heart function is controlled by a well-orchestrated interplay of different ion channels conducting Na+, Ca2+ and K+. Cardiac K+ channels are key players of cardiac repolarization counteracting depolarizating Na+ and Ca2+ currents. In contrast to Na+ and Ca2+, K+ is conducted by many different channels that differ in activation/deactivation kinetics as well as in their contribution to different phases of the action potential. Together with modulatory subunits these K+ channel α-subunits provide a wide range of repolarizing currents with specific characteristics. Moreover, due to expression differences, K+ channels strongly influence the time course of the action potentials in different heart regions. On the other hand, the variety of different K+ channels increase the number of possible disease-causing mutations. Up to now, a plethora of gain- as well as loss-of-function mutations in K+ channel forming or modulating proteins are known that cause severe congenital cardiac diseases like the long-QT-syndrome, the short-QT-syndrome, the Brugada syndrome and/or different types of atrial tachyarrhythmias. In this chapter we provide a comprehensive overview of different K+ channels in cardiac physiology and pathophysiology.
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11
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Maury P, Delasnerie H, Beneyto M, Rollin A. Autonomic cardiac innervation: impact on the evolution of arrhythmias in inherited cardiac arrhythmia syndromes. Herzschrittmacherther Elektrophysiol 2021; 32:308-314. [PMID: 34185133 DOI: 10.1007/s00399-021-00774-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 05/17/2021] [Indexed: 11/28/2022]
Abstract
The autonomic nervous system (ANS) is an essential component of arrhythmogenicity, especially in the absence of structural heart disease and channelopathy. In this article, the authors review the role and characteristics of ANS in various channelopathies. Some of these, such as most long QT syndromes and catecholaminergic polymorphic ventricular tachycardia, are highly dependent on sympathetic activation, while parasympathetic tone is an important factor for arrhythmias in other channelopathies such as Brugada syndrome or early repolarisation syndrome. Recent advances highlighting the subtle role of ANS in channelopathies are presented here, demonstrating that all is far from being so simple and straightforward and revealing some paradoxical behaviours of channelopathies in relation to discrete ANS imbalance.
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Affiliation(s)
- Philippe Maury
- Department of Cardiology, University Hospital Rangueil, Toulouse, France. .,I2MC, INSERM UMR 1297, Toulouse, France.
| | - Hubert Delasnerie
- Department of Cardiology, University Hospital Rangueil, Toulouse, France
| | - Maxime Beneyto
- Department of Cardiology, University Hospital Rangueil, Toulouse, France
| | - Anne Rollin
- Department of Cardiology, University Hospital Rangueil, Toulouse, France
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12
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Menahem S, Sehgal A, Meagher S. Early detection of significant congenital heart disease: The contribution of fetal cardiac ultrasound and newborn pulse oximetry screening. J Paediatr Child Health 2021; 57:323-327. [PMID: 33529483 DOI: 10.1111/jpc.15355] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/19/2022]
Abstract
Fetal cardiac and newborn pulse oximetry screening has greatly facilitated the detection of cardiac abnormalities, which may be serious with potentially dire neonatal consequences. The prenatal diagnosis of a serious cardiac abnormality allows the attending obstetrician to organise the much safer in-utero transfer of the fetus for delivery at a tertiary centre, particularly if there is evidence of a duct-dependent lesion that may require the infusion of Prostaglandin E1 to maintain duct patency pending surgical intervention. Newborn pulse oximetry alerts the paediatrician that the baby may have a significant cardiac abnormality, which warrants further elucidation prior to discharge, rather than for the baby to represent unwell a few days later. Despite these advances, serious cardiac abnormalities may be missed on screening. Their detection then falls back onto the clinical acumen of the attending paediatrician/family physician to review the history, carefully elicit and evaluate the clinical signs further aided by whatever investigations that may be available at the birthing hospital, frequently less resourced than the tertiary centres. At the outset, a brief synopsis is provided of the clinical findings that may point to a cardiac abnormality. That is followed by a critical review of the accuracy of prenatal and newborn pulse oximetry screening with emphasis on the lesions that may be missed. Suggestions are made as to how to improve the diagnostic accuracy.
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Affiliation(s)
- Samuel Menahem
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,School of Clinical Services, Monash University, Melbourne, Victoria, Australia
| | - Arvind Sehgal
- Monash Newborn, Monash Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
| | - Simon Meagher
- Department of Perinatal Medicine, University of Melbourne, Melbourne, Victoria, Australia.,Monash Ultrasound for Women, Melbourne, Victoria, Australia
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Alnajim FA, Alkhidhr MAS, Alanazi MAA, Bawazeer AAJ, Shahar AI, Alsharif BM, Alanazi OQK, Darraj OQI, Mohamed NM, Alawi AAM, Alsoghayer ABS. An overview of diagnosis and management of bradycardia. ARCHIVES OF PHARMACY PRACTICE 2021. [DOI: 10.51847/vpusknw32w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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14
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Wang M, Gao M, Fang S, Zheng R, Peng D, Luo Q, Yu B. L51P, a novel mutation in the PAS domain of hERG channel, confers long QT syndrome by impairing channel activation. Am J Transl Res 2020; 12:8040-8049. [PMID: 33437379 PMCID: PMC7791479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/28/2020] [Indexed: 06/12/2023]
Abstract
The human ether-à-go-go-related gene (hERG) potassium channel mediates the repolarization of ventricular action potentials. Mutations in the KCNH2 cause long QT syndrome (LQTS) and are associated with cardiac arrhythmias and sudden death. Here, we functionally analyzed a mutation of hERG potassium channel (p.L51P), gaining novel insights into clinical genotype-phenotype relationships. Potassium currents were recorded by whole-cell patch clamping in HEK293 cells transiently transfected with wild-type and/or mutant hERG potassium channel. Immunofluorescence assay and confocal imaging were undertaken to study the effects of L51P mutation on channel trafficking. The models of the protein structure of hERG and its mutations are predicted by Amber16 software. Molecular dynamics (MD) of individual protein were performed with Particle Mesh Ewald (PME). The production of MD simulations of hERG-WT and hERG-Mut at constant pressure and temperature were carried out with SHAKE. L51 was a conservative amino acid, located in the Per-Arnt-Sim (PAS) domain of the amino terminus. L51P caused loss of function via impairing channel activation. L51P was predicted to destroy hydrophobic structure in the PAS domain, thus causing the failure of channel opening. In summary, the present study identifies L51P as a novel mutation of hERG potassium channel. L51P mutation mechanistically impairs channel activation, reducing channel functionality.
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Affiliation(s)
- Mi Wang
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South UniversityChangsha, Hunan, China
- Research Institute of Blood Lipid and Atherosclerosis, Central South UniversityChangsha, Hunan, China
| | - Min Gao
- Department of Pharmacy, The Sixth Affiliated Hospital, Sun Yat-sen UniversityGuangzhou, Guangdong, China
| | - Senbiao Fang
- School of Computer Science and Engineering, Central South UniversityChangsha, Hunan, China
| | - Ruoqian Zheng
- School of Computer Science and Engineering, Central South UniversityChangsha, Hunan, China
| | - Daoquan Peng
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South UniversityChangsha, Hunan, China
- Research Institute of Blood Lipid and Atherosclerosis, Central South UniversityChangsha, Hunan, China
| | - Qin Luo
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South UniversityChangsha, Hunan, China
- Research Institute of Blood Lipid and Atherosclerosis, Central South UniversityChangsha, Hunan, China
| | - Bilian Yu
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South UniversityChangsha, Hunan, China
- Research Institute of Blood Lipid and Atherosclerosis, Central South UniversityChangsha, Hunan, China
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15
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Abstract
Congenital Long QT Syndrome (LQTS) is a dangerous arrhythmic disorder that can be diagnosed in children with bradycardia. It is characterised by a prolonged QT interval and torsades de pointes that may cause sudden death. Long QT syndrome is an ion channelopathy with complex molecular and physiological infrastructure. Unlike the acquired type, congenital LQTS has a genetic inheritance and it may be diagnosed by syncope, stress in activity, cardiac dysfunction, sudden death or sometimes incidentally. Permanent pacemaker implantation is required for LQTS with resistant bradycardia even in children to resolve symptoms and avoid sudden death.
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Oscanoa TJ, Vidal X, Kanters JK, Romero-Ortuno R. Frequency of Long QT in Patients with SARS-CoV-2 Infection Treated with Hydroxychloroquine: A Meta-analysis. Int J Antimicrob Agents 2020; 56:106212. [PMID: 33164789 PMCID: PMC7584880 DOI: 10.1016/j.ijantimicag.2020.106212] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 09/28/2020] [Accepted: 10/17/2020] [Indexed: 02/07/2023]
Abstract
Introduction Hydroxychloroquine (HCQ) has been proposed as a SARS-CoV-2 treatment but the frequency of long QT (LQT) during use is unknown. Objective To conduct a meta-analysis of the frequency of LQT in patients with SARS-CoV-2 infection treated with HCQ. Data Sources PubMed, EMBASE, Google Scholar, the Cochrane Database of Systematic Reviews and preprint servers (medRxiv, Research Square) were searched for studies published between December 2019 and June 30, 2020. Methods Effect statistics were pooled using random effects. The quality of observational studies and randomized controlled trials was appraised with STROBE and the Cochrane Risk of Bias Assessment tools, respectively. Outcomes Critical LQT was defined as: (1) maximum QT corrected (QTc)≥500 ms (if QRS<120 ms) or QTc≥550 ms (if QRS≥120 ms), and (2) QTc increase ≥60 ms. Results In the 28 studies included (n=9124), the frequency of LQT during HCQ treatment was 6.7% (95% confidence interval [CI]: 3.7-10.2). In 20 studies (n=7825), patients were also taking other QT-prolonging drugs. The frequency of LQT in the other 8 studies (n=1299) was 1.7% (95% CI: 0.3-3.9). Twenty studies (n=6869) reported HCQ discontinuation due to LQT, with a frequency of 3.7% (95% CI: 1.5-6.6). The frequency of ventricular arrhythmias during HCQ treatment was 1.68% (127/7539) and that of arrhythmogenic death was 0.69% (39/5648). Torsades de Pointes occurred in 0.06% (3/5066). Patients aged >60 years were at highest risk of HCQ-associated LQT (P<0.001). Conclusions HCQ-associated cardiotoxicity in SARS-CoV-2 patients is uncommon but requires ECG monitoring, particularly in those aged >60 years and/or taking other QT-prolonging drugs.
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Affiliation(s)
- Teodoro J Oscanoa
- Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Drug Safety Research Center, Facultad de Medicina Humana, Universidad de San Martín de Porres. Hospital Almenara, ESSALUD, Lima, Perú.
| | - Xavier Vidal
- Clinical Pharmacology Department, Vall d'Hebron Hospital, Barcelona, Spain
| | - Jørgen K Kanters
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Roman Romero-Ortuno
- Discipline of Medical Gerontology, Mercer's Institute for Successful Ageing, St James's Hospital, Dublin, Ireland; Global Brain Health Institute, Trinity College Dublin, Ireland
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Chou Y, Zhang A, Gu J, Liu J, Gu Y. A recognition method for extreme bradycardia by arterial blood pressure signal modeling with curve fitting. Physiol Meas 2020; 41:074002. [DOI: 10.1088/1361-6579/ab998d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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19
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Huang Y, Alsabbagh MW. Comparative risk of cardiac arrhythmias associated with acetylcholinesterase inhibitors used in treatment of dementias - A narrative review. Pharmacol Res Perspect 2020; 8:e00622. [PMID: 32691984 PMCID: PMC7372915 DOI: 10.1002/prp2.622] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/08/2020] [Accepted: 06/09/2020] [Indexed: 12/15/2022] Open
Abstract
Donepezil, galantamine, and rivastigmine are the three acetylcholinesterase inhibitors (AChEIs), out of a total of only four medications prescribed in the treatment of Alzheimer's Disease (AD) and related dementias. These medications are known to be associated with bradycardia given their mechanism of action of increasing acetylcholine (ACh). However, in March 2015, donepezil was added to the CredibleMeds "known-risk" category, a list where medications have a documented risk for acquired long-QT syndrome (ALQTS) and torsades de pointes (TdP) - a malignant ventricular arrhythmia that is a different adverse event than bradycardia (and is not necessarily associated with ACh action). The purpose of this article is to review the three AChEIs, especially with regards to mechanistic differences that may explain why only donepezil poses this risk; several pharmacological mechanisms may explain why. However, from an empirical point-of-view, aside from some case-reports, only a limited number of studies have generated relevant information regarding AChEIs' and electrocardiogram findings; none have specifically compared donepezil against galantamine or rivastigmine for malignant arrhythmias such as TdP. Currently, the choice of one of the three AChEIs for treatment of AD symptoms is primarily dependent upon clinician and patient preference. However, clinicians should be aware of the potential increased risk associated with donepezil. There is a need to examine the comparative risk of malignant arrhythmias among AChEIs users in real-world practice; this may have important implications with regards to changes in AChEI prescribing patterns.
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Affiliation(s)
- Yichang Huang
- School of PharmacyFaculty of ScienceUniversity of WaterlooKitchenerCanada
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20
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Saleh M, Gabriels J, Chang D, Soo Kim B, Mansoor A, Mahmood E, Makker P, Ismail H, Goldner B, Willner J, Beldner S, Mitra R, John R, Chinitz J, Skipitaris N, Mountantonakis S, Epstein LM. Effect of Chloroquine, Hydroxychloroquine, and Azithromycin on the Corrected QT Interval in Patients With SARS-CoV-2 Infection. Circ Arrhythm Electrophysiol 2020; 13:e008662. [PMID: 32347743 PMCID: PMC7299095 DOI: 10.1161/circep.120.008662] [Citation(s) in RCA: 220] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 04/28/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND The novel SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is responsible for the global coronavirus disease 2019 pandemic. Small studies have shown a potential benefit of chloroquine/hydroxychloroquine±azithromycin for the treatment of coronavirus disease 2019. Use of these medications alone, or in combination, can lead to a prolongation of the QT interval, possibly increasing the risk of Torsade de pointes and sudden cardiac death. METHODS Hospitalized patients treated with chloroquine/hydroxychloroquine±azithromycin from March 1 to the 23 at 3 hospitals within the Northwell Health system were included in this prospective, observational study. Serial assessments of the QT interval were performed. The primary outcome was QT prolongation resulting in Torsade de pointes. Secondary outcomes included QT prolongation, the need to prematurely discontinue any of the medications due to QT prolongation, and arrhythmogenic death. RESULTS Two hundred one patients were treated for coronavirus disease 2019 with chloroquine/hydroxychloroquine. Ten patients (5.0%) received chloroquine, 191 (95.0%) received hydroxychloroquine, and 119 (59.2%) also received azithromycin. The primary outcome of torsade de pointes was not observed in the entire population. Baseline corrected QT interval intervals did not differ between patients treated with chloroquine/hydroxychloroquine (monotherapy group) versus those treated with combination group (chloroquine/hydroxychloroquine and azithromycin; 440.6±24.9 versus 439.9±24.7 ms, P=0.834). The maximum corrected QT interval during treatment was significantly longer in the combination group versus the monotherapy group (470.4±45.0 ms versus 453.3±37.0 ms, P=0.004). Seven patients (3.5%) required discontinuation of these medications due to corrected QT interval prolongation. No arrhythmogenic deaths were reported. CONCLUSIONS In the largest reported cohort of coronavirus disease 2019 patients to date treated with chloroquine/hydroxychloroquine±azithromycin, no instances of Torsade de pointes, or arrhythmogenic death were reported. Although use of these medications resulted in QT prolongation, clinicians seldomly needed to discontinue therapy. Further study of the need for QT interval monitoring is needed before final recommendations can be made.
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Affiliation(s)
- Moussa Saleh
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
- Division of Electrophysiology, Department of Cardiology, Lenox Hill Hospital, Northwell Health, New York, NY (M.S., P.M., N.S., S.M.)
| | - James Gabriels
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
| | - David Chang
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
| | - Beom Soo Kim
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
| | - Amtul Mansoor
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
| | - Eitezaz Mahmood
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
| | - Parth Makker
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
- Division of Electrophysiology, Department of Cardiology, Lenox Hill Hospital, Northwell Health, New York, NY (M.S., P.M., N.S., S.M.)
| | - Haisam Ismail
- Division of Electrophysiology, Department of Cardiology, Long Island Jewish Medical Center, Northwell Health, New Hyde Park (H.I., B.G.)
| | - Bruce Goldner
- Division of Electrophysiology, Department of Cardiology, Long Island Jewish Medical Center, Northwell Health, New Hyde Park (H.I., B.G.)
| | - Jonathan Willner
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
| | - Stuart Beldner
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
| | - Raman Mitra
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
| | - Roy John
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
| | - Jason Chinitz
- Division of Electrophysiology, Department of Cardiology, Southside Hospital, Northwell Health, Bay Shore (J.C.)
| | - Nicholas Skipitaris
- Division of Electrophysiology, Department of Cardiology, Lenox Hill Hospital, Northwell Health, New York, NY (M.S., P.M., N.S., S.M.)
| | - Stavros Mountantonakis
- Division of Electrophysiology, Department of Cardiology, Lenox Hill Hospital, Northwell Health, New York, NY (M.S., P.M., N.S., S.M.)
| | - Laurence M. Epstein
- Division of Electrophysiology, Department of Cardiology, North Shore University Hospital, Northwell Health, Manhasset, NY (M.S., J.G., D.C., B.S.K., A.M., E.M., P.M., J.W., S.B., R.M., R.J., L.M.E.)
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Widatalla N, Kasahara Y, Kimura Y, Khandoker A. Model based estimation of QT intervals in non-invasive fetal ECG signals. PLoS One 2020; 15:e0232769. [PMID: 32392232 PMCID: PMC7213701 DOI: 10.1371/journal.pone.0232769] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/21/2020] [Indexed: 11/18/2022] Open
Abstract
The end timing of T waves in fetal electrocardiogram (fECG) is important for the evaluation of ST and QT intervals which are vital markers to assess cardiac repolarization patterns. Monitoring malignant fetal arrhythmias in utero is fundamental to care in congenital heart anomalies preventing perinatal death. Currently, reliable detection of end of T waves is possible only by using fetal scalp ECG (fsECG) and fetal magnetocardiography (fMCG). fMCG is expensive and less accessible and fsECG is an invasive technique available only during intrapartum period. Another safer and affordable alternative is the non-invasive fECG (nfECG) which can provide similar assessment provided by fsECG and fMECG but with less accuracy (not beat by beat). Detection of T waves using nfECG is challenging because of their low amplitudes and high noise. In this study, a novel model-based method that estimates the end of T waves in nfECG signals is proposed. The repolarization phase has been modeled as the discharging phase of a capacitor. To test the model, fECG signals were collected from 58 pregnant women (age: (34 ± 6) years old) bearing normal and abnormal fetuses with gestational age (GA) 20-41 weeks. QT and QTc intervals have been calculated to test the level of agreement between the model-based and reference values (fsECG and Doppler Ultrasound (DUS) signals) in normal subjects. The results of the test showed high agreement between model-based and reference values (difference < 5%), which implies that the proposed model could be an alternative method to detect the end of T waves in nfECG signals.
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Affiliation(s)
- Namareq Widatalla
- Next Generation Biological Information Technology, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
- * E-mail:
| | - Yoshiyuki Kasahara
- Next Generation Biological Information Technology, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
- Advanced Interdisciplinary Biomedical Engineering, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yoshitaka Kimura
- Next Generation Biological Information Technology, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
- Advanced Interdisciplinary Biomedical Engineering, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ahsan Khandoker
- Healthcare Engineering Innovation Center (HEIC), Department of Biomedical Engineering, Khalifa University, Abu Dhabi, UAE
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22
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Kistamás K, Veress R, Horváth B, Bányász T, Nánási PP, Eisner DA. Calcium Handling Defects and Cardiac Arrhythmia Syndromes. Front Pharmacol 2020; 11:72. [PMID: 32161540 PMCID: PMC7052815 DOI: 10.3389/fphar.2020.00072] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Calcium ions (Ca2+) play a major role in the cardiac excitation-contraction coupling. Intracellular Ca2+ concentration increases during systole and falls in diastole thereby determining cardiac contraction and relaxation. Normal cardiac function also requires perfect organization of the ion currents at the cellular level to drive action potentials and to maintain action potential propagation and electrical homogeneity at the tissue level. Any imbalance in Ca2+ homeostasis of a cardiac myocyte can lead to electrical disturbances. This review aims to discuss cardiac physiology and pathophysiology from the elementary membrane processes that can cause the electrical instability of the ventricular myocytes through intracellular Ca2+ handling maladies to inherited and acquired arrhythmias. Finally, the paper will discuss the current therapeutic approaches targeting cardiac arrhythmias.
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Affiliation(s)
- Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - Roland Veress
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - David A Eisner
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
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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.
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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
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24
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Wilders R. Cellular Mechanisms of Sinus Node Dysfunction in Carriers of the SCN5A-E161K Mutation and Role of the H558R Polymorphism. Front Physiol 2018; 9:1795. [PMID: 30618807 PMCID: PMC6305593 DOI: 10.3389/fphys.2018.01795] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/29/2018] [Indexed: 12/16/2022] Open
Abstract
Background: Carriers of the E161K mutation in the SCN5A gene, encoding the NaV1.5 pore-forming α-subunit of the ion channel carrying the fast sodium current (INa), show sinus bradycardia and occasional exit block. Voltage clamp experiments in mammalian expression systems revealed a mutation-induced 2.5- to 4-fold reduction in INa peak current density as well as a +19 mV shift and reduced steepness of the steady-state activation curve. The highly common H558R polymorphism in NaV1.5 limits this shift to +13 mV, but also introduces a -10 mV shift in steady-state inactivation. Aim: We assessed the cellular mechanism by which the E161K mutation causes sinus node dysfunction in heterozygous mutation carriers as well as the potential role of the H558R polymorphism. Methods: We incorporated the mutation-induced changes in INa into the Fabbri-Severi model of a single human sinoatrial node cell and the Maleckar et al. human atrial cell model, and carried out simulations under control conditions and over a wide range of acetylcholine levels. Results: In absence of the H558R polymorphism, the E161K mutation increased the basic cycle length of the sinoatrial node cell from 813 to 866 ms. In the simulated presence of 10 and 25 nM acetylcholine, basic cycle length increased from 1027 to 1131 and from 1448 to 1795 ms, respectively. The increase in cycle length was the result of a significant slowing of diastolic depolarization. The mutation-induced reduction in INa window current had reduced the contribution of the mutant component of INa to the net membrane current during diastolic depolarization to effectively zero. Highly similar results were obtained in presence of the H558R polymorphism. Atrial excitability was reduced, both in absence and presence of the H558R polymorphism, as reflected by an increase in threshold stimulus current and a concomitant decrease in capacitive current of the atrial cell. Conclusion: We conclude that the experimentally identified mutation-induced changes in INa can explain the clinically observed sinus bradycardia and potentially the occasional exit block. Furthermore, we conclude that the common H558R polymorphism does not significantly alter the effects of the E161K mutation and can thus not explain the reduced penetrance of the E161K mutation.
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Affiliation(s)
- Ronald Wilders
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, Netherlands
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25
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Verkerk AO, Amin AS, Remme CA. Disease Modifiers of Inherited SCN5A Channelopathy. Front Cardiovasc Med 2018; 5:137. [PMID: 30327767 PMCID: PMC6174200 DOI: 10.3389/fcvm.2018.00137] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/10/2018] [Indexed: 12/19/2022] Open
Abstract
To date, a large number of mutations in SCN5A, the gene encoding the pore-forming α-subunit of the primary cardiac Na+ channel (NaV1.5), have been found in patients presenting with a wide range of ECG abnormalities and cardiac syndromes. Although these mutations all affect the same NaV1.5 channel, the associated cardiac syndromes each display distinct phenotypical and biophysical characteristics. Variable disease expressivity has also been reported, where one particular mutation in SCN5A may lead to either one particular symptom, a range of various clinical signs, or no symptoms at all, even within one single family. Additionally, disease severity may vary considerably between patients carrying the same mutation. The exact reasons are unknown, but evidence is increasing that various cardiac and non-cardiac conditions can influence the expressivity and severity of inherited SCN5A channelopathies. In this review, we provide a summary of identified disease entities caused by SCN5A mutations, and give an overview of co-morbidities and other (non)-genetic factors which may modify SCN5A channelopathies. A comprehensive knowledge of these modulatory factors is not only essential for a complete understanding of the diverse clinical phenotypes associated with SCN5A mutations, but also for successful development of effective risk stratification and (alternative) treatment paradigms.
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Affiliation(s)
- Arie O Verkerk
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands.,Department of Medical Biology, Academic Medical Center, Amsterdam, Netherlands
| | - Ahmad S Amin
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands
| | - Carol Ann Remme
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands
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