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Markman TM, Marchlinski FE, Callans DJ, Frankel DS. Programmed Ventricular Stimulation: Risk Stratification and Guiding Antiarrhythmic Therapies. JACC Clin Electrophysiol 2024; 10:1489-1507. [PMID: 38661601 DOI: 10.1016/j.jacep.2024.02.034] [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: 01/16/2024] [Accepted: 02/13/2024] [Indexed: 04/26/2024]
Abstract
Electrophysiologic testing with programmed ventricular stimulation (PVS) has been utilized to induce ventricular tachycardia (VT), thereby improving risk stratification for patients with ischemic and nonischemic cardiomyopathies and determining the effectiveness of antiarrhythmic therapies, especially catheter ablation. A variety of procedural aspects can be modified during PVS in order to alter the sensitivity and specificity of the test including the addition of multiple baseline pacing cycle lengths, extrastimuli, and pacing locations. The definition of a positive result is also critically important, which has varied from exclusively sustained monomorphic VT (>30 seconds) to any ventricular arrhythmia regardless of morphology. In this review, we discuss the history of PVS and evaluate its role in sudden cardiac death risk stratification in a variety of patient populations. We propose an approach to future investigations that will capitalize on the unique ability to vary the sensitivity and specificity of this test. We then discuss the application of PVS during and following catheter ablation. The strategies that have been utilized to improve the efficacy of intraprocedural PVS are highlighted during a discussion of the limitations of this probabilistic strategy. The role of noninvasive programmed stimulation is also reviewed in predicting recurrent VT and informing management decisions including repeat ablations, modifications in antiarrhythmic drugs, and implantable cardioverter-defibrillator programming. Based on the available evidence and guidelines, we propose an approach to future investigations that will allow clinicians to optimize the use of PVS for risk stratification and assessment of therapeutic efficacy.
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Affiliation(s)
- Timothy M Markman
- Cardiovascular Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Francis E Marchlinski
- Cardiovascular Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David J Callans
- Cardiovascular Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David S Frankel
- Cardiovascular Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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2
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Ma JF, Zhou Y, Fu HX. Ventricular fibrillation induced by fever in structurally normal hearts. Front Cardiovasc Med 2023; 10:1230295. [PMID: 37817866 PMCID: PMC10561293 DOI: 10.3389/fcvm.2023.1230295] [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: 07/24/2023] [Accepted: 08/25/2023] [Indexed: 10/12/2023] Open
Abstract
Ventricular fibrillation (VF) is a life-threatening arrhythmia that usually happens in patients with structural heart diseases. However, fever-induced ventricular fibrillation in structurally normal hearts was reported, and the four main diseases associated with these cases were Brugada syndrome, long QT syndrome, idiopathic ventricular fibrillation, and non-cardiovascular diseases. In this review, we analyzed this phenomenon and its clinical characteristics.
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Affiliation(s)
- Ji-Fang Ma
- Department of Cardiology, Fuwai Central China Cardiovascular Hospital, Zhengzhou, China
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3
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Yılmaz E, Özdemir F. Brugada Phenocopy Induced by Hypovolemic Hyponatremia. Cureus 2023; 15:e45667. [PMID: 37868457 PMCID: PMC10589819 DOI: 10.7759/cureus.45667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2023] [Indexed: 10/24/2023] Open
Abstract
Brugada syndrome (BrS) is a hereditary channelopathy caused by an autosomal dominant mutation in the cardiac sodium channel gene SCN5A alpha subunit. In individuals without structural heart disease, the risk of sudden cardiac death (SCD) increases in this channelopathy with ST-segment elevation in V1-3 precordials. Brugada phenocopy (BrP) is a condition in which transient ST-segment elevations are observed, mimicking BrS electrocardiographic changes, which can occur with electrolyte and metabolic disorder scenarios. In this study, we share a case of BrP that occurred due to hypovolemic hyponatremia and recovered spontaneously with the correction of electrolyte disturbance.
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Affiliation(s)
- Emre Yılmaz
- Cardiology, Giresun University, Faculty of Medicine, Giresun, TUR
| | - Fatih Özdemir
- Cardiology, Giresun University, Faculty of Medicine, Giresun, TUR
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4
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Di Diego JM, Barajas-Martinez H, Cox R, Robinson VM, Jung J, Fouda M, Patocskai B, Abdelsayed M, Ruben PC, Antzelevitch C. Mechanisms underlying the antiarrhythmic effect of ARumenamide-787 in experimental models of the J wave syndromes and hypothermia. PLoS One 2023; 18:e0281977. [PMID: 37159454 PMCID: PMC10168548 DOI: 10.1371/journal.pone.0281977] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 02/05/2023] [Indexed: 05/11/2023] Open
Abstract
BACKGROUND Brugada (BrS) and early repolarization syndromes (ERS), the so-called J wave syndromes (JWS), are associated with life-threatening ventricular arrhythmias. Pharmacologic approaches to therapy are currently limited. In this study, we examine the effects of ARumenamide-787 (AR-787) to suppress the electrocardiographic and arrhythmic manifestations of JWS and hypothermia. METHODS We studied the effects of AR-787 on INa and IKr in HEK-293 cells stably expressing the α- and β1-subunits of the cardiac (NaV1.5) sodium channel and hERG channel, respectively. In addition, we studied its effect on Ito, INa and ICa in dissociated canine ventricular myocytes along with action potentials and ECG from coronary-perfused right (RV) and left (LV) ventricular wedge preparations. The Ito agonist, NS5806 (5-10 μM), ICa blocker, verapamil (2.5 μM), and INa blocker, ajmaline (2.5 μM), were used to mimic the genetic defects associated with JWS and to induce the electrocardiographic and arrhythmic manifestations of JWS (prominent J waves/ST segment elevation, phase 2 reentry and polymorphic VT/VF) in canine ventricular wedge preparations. RESULTS AR-787 (1, 10 and 50 μM) exerted pleiotropic effects on cardiac ion channels. The predominant effect was inhibition of the transient outward current (Ito) and enhancement of the sodium channel current (INa), with lesser effects to inhibit IKr and augment calcium channel current (ICa). AR-787 diminished the electrocardiographic J wave and prevented and/or suppressed all arrhythmic activity in canine RV and LV experimental models of BrS, ERS and hypothermia. CONCLUSIONS Our findings point to AR-787 as promising candidate for the pharmacologic treatment of JWS and hypothermia.
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Affiliation(s)
- José M. Di Diego
- Lankenau Institute for Medical Research, Wynnewood, PA, United States of America
| | - Hector Barajas-Martinez
- Lankenau Institute for Medical Research, Wynnewood, PA, United States of America
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States of America
| | - Robert Cox
- Lankenau Institute for Medical Research, Wynnewood, PA, United States of America
| | - Victoria M. Robinson
- Lankenau Institute for Medical Research, Wynnewood, PA, United States of America
| | - Joseph Jung
- Lankenau Institute for Medical Research, Wynnewood, PA, United States of America
| | | | - Bence Patocskai
- Lankenau Institute for Medical Research, Wynnewood, PA, United States of America
| | | | | | - Charles Antzelevitch
- Lankenau Institute for Medical Research, Wynnewood, PA, United States of America
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States of America
- Lankenau Heart Institute, Wynnewood, PA, United States of America
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5
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Penttinen K, Prajapati C, Shah D, Rajan DK, Cherian RM, Swan H, Aalto-Setälä K. HiPSC-derived cardiomyocyte to model Brugada syndrome: both asymptomatic and symptomatic mutation carriers reveal increased arrhythmogenicity. BMC Cardiovasc Disord 2023; 23:208. [PMID: 37098502 PMCID: PMC10131315 DOI: 10.1186/s12872-023-03234-7] [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: 11/14/2022] [Accepted: 04/11/2023] [Indexed: 04/27/2023] Open
Abstract
Brugada syndrome is an inherited cardiac arrhythmia disorder that is mainly associated with mutations of the cardiac voltage-gated sodium channel alpha subunit 5 (SCN5A) gene. The clinical symptoms include ventricular fibrillation and an increased risk of sudden cardiac death. Human-induced pluripotent stem cell (hiPSC) lines were derived from symptomatic and asymptomatic individuals carrying the R1913C mutation in the SCN5A gene. The present work aimed to observe the phenotype-specific differences in hiPSC-derived cardiomyocytes (CMs) obtained from symptomatic and asymptomatic mutation carriers. In this study, CM electrophysiological properties, beating abilities and calcium parameters were measured. Mutant CMs exhibited higher average sodium current densities than healthy CMs, but the differences were not statistically significant. Action potential durations were significantly shorter in CMs from the symptomatic individual, and a spike-and-dome morphology of action potential was exclusively observed in CMs from the symptomatic individual. More arrhythmias occurred in mutant CMs at single cell and cell aggregate levels compared with those observed in wild-type CMs. Moreover, there were no major differences in ionic currents or intracellular calcium dynamics between the CMs of asymptomatic and symptomatic individuals after the administration of adrenaline and flecainide.In conclusion, mutant CMs were more prone to arrhythmia than healthy CMs but did not explain why only one of the mutation carriers was symptomatic.
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Affiliation(s)
- Kirsi Penttinen
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, Tampere, 33520, Finland
| | - Chandra Prajapati
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, Tampere, 33520, Finland.
| | - Disheet Shah
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, Tampere, 33520, Finland
| | - Dhanesh Kattipparambil Rajan
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, Tampere, 33520, Finland
| | - Reeja Maria Cherian
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, Tampere, 33520, Finland
| | - Heikki Swan
- Helsinki University Hospital, Helsinki, 00290, Finland
| | - Katriina Aalto-Setälä
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, Tampere, 33520, Finland
- Heart Hospital, Tampere University Hospital, Tampere, 33520, Finland
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6
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Popa IP, Șerban DN, Mărănducă MA, Șerban IL, Tamba BI, Tudorancea I. Brugada Syndrome: From Molecular Mechanisms and Genetics to Risk Stratification. Int J Mol Sci 2023; 24:ijms24043328. [PMID: 36834739 PMCID: PMC9967917 DOI: 10.3390/ijms24043328] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/13/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Brugada syndrome (BrS) is a rare hereditary arrhythmia disorder, with a distinctive ECG pattern, correlated with an increased risk of ventricular arrhythmias and sudden cardiac death (SCD) in young adults. BrS is a complex entity in terms of mechanisms, genetics, diagnosis, arrhythmia risk stratification, and management. The main electrophysiological mechanism of BrS requires further research, with prevailing theories centered on aberrant repolarization, depolarization, and current-load match. Computational modelling, pre-clinical, and clinical research show that BrS molecular anomalies result in excitation wavelength (k) modifications, which eventually increase the risk of arrhythmia. Although a mutation in the SCN5A (Sodium Voltage-Gated Channel Alpha Subunit 5) gene was first reported almost two decades ago, BrS is still currently regarded as a Mendelian condition inherited in an autosomal dominant manner with incomplete penetrance, despite the recent developments in the field of genetics and the latest hypothesis of additional inheritance pathways proposing a more complex mode of inheritance. In spite of the extensive use of the next-generation sequencing (NGS) technique with high coverage, genetics remains unexplained in a number of clinically confirmed cases. Except for the SCN5A which encodes the cardiac sodium channel NaV1.5, susceptibility genes remain mostly unidentified. The predominance of cardiac transcription factor loci suggests that transcriptional regulation is essential to the Brugada syndrome's pathogenesis. It appears that BrS is a multifactorial disease, which is influenced by several loci, each of which is affected by the environment. The primary challenge in individuals with a BrS type 1 ECG is to identify those who are at risk for sudden death, researchers propose the use of a multiparametric clinical and instrumental strategy for risk stratification. The aim of this review is to summarize the latest findings addressing the genetic architecture of BrS and to provide novel perspectives into its molecular underpinnings and novel models of risk stratification.
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Affiliation(s)
- Irene Paula Popa
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
| | - Dragomir N. Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Minela Aida Mărănducă
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Ionela Lăcrămioara Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Bogdan Ionel Tamba
- Department of Pharmacology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
- Correspondence:
| | - Ionuț Tudorancea
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
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7
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Asfour I, Sherif AA, Bhattad PB, Mishra AK, Sharma N, Kranis M. Brugada Sign in a Cardiac Transplant Donor. Cureus 2022; 14:e27619. [PMID: 36059349 PMCID: PMC9433790 DOI: 10.7759/cureus.27619] [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] [Accepted: 08/01/2022] [Indexed: 11/05/2022] Open
Abstract
Brugada syndrome (BrS) is a rare entity represented by the Brugada sign on an electrocardiogram (EKG) and is associated with sudden cardiac death (SCD). There is little data to guide the management of donor Brugada syndrome in the setting of cardiac transplantation. A 31-year-old male sustained out-of-hospital cardiac arrest secondary to polysubstance use and was found asystole. Bystander cardiopulmonary resuscitation (CPR) with advanced cardiovascular life support (ACLS) protocol was initiated. Return of spontaneous circulation (ROSC) was achieved and the patient was taken to the emergency room (ER) in sinus rhythm with an initial presenting EKG showing the Brugada sign. A toxicological screen for cocaine was positive. The patient was eventually declared brain dead and underwent angiographic and echocardiographic evaluation as a donor heart for cardiac transplantation and was accepted for transplantation. Cardiac arrest in a young patient with a Brugada sign on EKG is a concern for BrS. Cocaine exerts a sodium channel blockade that can unmask BrS. Genetic testing for sodium voltage-gated channel alpha subunit 5 (SCN5A) gene mutation was negative, however, only 15% to 30% of patients carry the mutation. We proceeded with cardiac transplantation and suggested an implantable cardioverter defibrillator (ICD) for primary prevention in the recipient, should further specialized testing reveal a continued concern for BrS. We suggest the necessity for further data to guide decisions in patients with BrS undergoing cardiac transplantation.
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8
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Yakkali S, Teresa Selvin S, Thomas S, Bikeyeva V, Abdullah A, Radivojevic A, Abu Jad AA, Ravanavena A, Ravindra C, Igweonu-Nwakile EO, Ali S, Paul S, Hamid P. Why Is There an Increased Risk for Sudden Cardiac Death in Patients With Early Repolarization Syndrome? Cureus 2022; 14:e26820. [PMID: 35971350 PMCID: PMC9374281 DOI: 10.7759/cureus.26820] [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: 06/07/2022] [Accepted: 07/13/2022] [Indexed: 11/29/2022] Open
Abstract
The last two decades have changed the viewpoint on early repolarization syndrome (ERS). The prevalence of the early repolarization pattern is variable and ranges between 3-24% depending upon age, gender, and criteria used for J-point upliftment from baseline (0.05mV vs. 1 mV). While this pattern was previously linked with a benign result, multiple recent investigations have found a link between early repolarization and Sudden Cardiac Death (SCD) by causing life-threatening arrhythmias like Ventricular tachycardia/Ventricular fibrillation, a condition known as early repolarization syndrome. The syndrome falls under a broader bracket of J wave syndromes, which can be caused by early repolarization or depolarization abnormalities. The characteristics of early repolarization that are considered high risk for Sudden Cardiac Death include the amplitude of J-point upliftment from baseline ( > 0.2 mV), Inferior-lateral location of Early Repolarization pattern, and horizontal and downsloping ST-segment. Patients with symptomatic early repolarisation patterns on ECG are more likely to have repeated cardiac episodes. Implantable Cardioverter-Defibrillator (ICD) implantation and isoproterenol are the recommended treatments in symptomatic patients. On the other hand, asymptomatic patients with early repolarization patterns are prevalent and have a better outcome. Risk categorization is still obscure in asymptomatic early repolarization patterns. This traditional review outlines the known knowledge of pathophysiology behind the increased risk of sudden cardiac death, risk stratification of patients with ERS, and the treatment guidelines for patients with ERS. Further prospective studies are recommended to elucidate the exact mechanism for ventricular arrhythmogenesis in ERS patients and to risk stratifying asymptomatic patients with ERS.
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9
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King DR, Hardin KM, Hoeker GS, Poelzing S. Re-evaluating methods reporting practices to improve reproducibility: an analysis of methodological rigor for the Langendorff whole-heart technique. Am J Physiol Heart Circ Physiol 2022; 323:H363-H377. [PMID: 35749719 PMCID: PMC9359653 DOI: 10.1152/ajpheart.00164.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In recent decades, the scientific community has seen an increased interest in rigor and reproducibility. In 2017, concerns of methodological thoroughness and reporting practices were implicated as significant barriers to reproducibility within the preclinical cardiovascular literature, particularly in studies employing animal research. The Langendorff, whole-heart technique has proven to be an invaluable research tool, being modified in a myriad of ways to probe questions across the spectrum of physio- and pathophysiologic function of the heart. As a result, significant variability in the application of the Langendorff technique exists. This literature review quantifies the different methods employed in the implementation of the Langendorff technique and provides brief examples of how individual parametric differences can impact the outcomes and interpretation of studies. From 2017-2020, significant variability of animal models, anesthesia, cannulation time, and perfusate composition, pH, and temperature demonstrate that the technique has diversified to meet new challenges and answer different scientific questions. The review also reveals which individual methods are most frequently reported, even if there is no explicit agreement upon which parameters should be reported. The analysis of methods related to the Langendorff technique suggests a framework for considering methodological approach when interpreting seemingly contradictory results, rather than concluding that results are irreproducible.
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Affiliation(s)
- D Ryan King
- Translational Biology, Medicine, and Health Graduate Program. Virginia Polytechnic Institute and State University. Blacksburg, Virginia.,Dorothy M. Davis Heart and Lunch Research Institute, College of Medicine, The Ohio State University Wexner Medical Center. Columbus, Ohio
| | - Kathryn M Hardin
- Virginia Tech Carilion School of Medicine. Roanoke, Virginia.,Center for Heart and Reparative Medicine Research. Fralin Biomedical Research Institute at Virginia Tech Carilion. Roanoke, Virginia
| | - Gregory S Hoeker
- Center for Heart and Reparative Medicine Research. Fralin Biomedical Research Institute at Virginia Tech Carilion. Roanoke, Virginia
| | - Steven Poelzing
- Virginia Tech Carilion School of Medicine. Roanoke, Virginia.,Center for Heart and Reparative Medicine Research. Fralin Biomedical Research Institute at Virginia Tech Carilion. Roanoke, Virginia.,Department of Biomedical Engineering and Mechanics. Virginia Polytechnic Institute and State University. Blacksburg, Virginia
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10
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Zimmermann P, Aberer F, Braun M, Sourij H, Moser O. The Arrhythmogenic Face of COVID-19: Brugada ECG Pattern in SARS-CoV-2 Infection. J Cardiovasc Dev Dis 2022; 9:jcdd9040096. [PMID: 35448072 PMCID: PMC9027624 DOI: 10.3390/jcdd9040096] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 12/15/2022] Open
Abstract
In 1992, Brugada syndrome (BS) was first described; an often unrecognized cardiac conduction disorder mainly associated with unexplained sudden cardiac arrest and consecutive syncope. Nevertheless, the pathomechanism of BS and sudden cardiac death remains mainly explained. Mutations in the cardiac sodium channels, which cause a reduction or functional loss of these channels, are associated with characteristic electrocardiographic (ECG) abnormalities and malignant arrhythmia. The majority of affected people are previously healthy and unaware of their genetic predisposition for BS and might experience ventricular tachyarrhythmias and cardiac arrest potentially triggered by several factors (e.g., alcohol, sodium channel blockers, psychotropic drugs, and fever). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was firstly identified in Wuhan in early December 2019 and rapidly spread worldwide as coronavirus disease (COVID-19). COVID-19 is typically characterized by a severe inflammatory response, activation of the immune system, and high febrile illness. Due to this condition, symptomatic COVID-19 infection or vaccination might serve as inciting factor for unmasking the Brugada pattern and represents a risk factor for developing proarrhythmic complications. The aim of this narrative review was to detail the association between virus-related issues such as fever, electrolyte disturbance, and inflammatory stress of COVID-19 infection with transient Brugada-like symptoms and ECG-pattern and its susceptibility to proarrhythmogenic episodes.
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Affiliation(s)
- Paul Zimmermann
- Department of Sport Science, Division of Exercise Physiology and Metabolism, University of Bayreuth, 95447 Bayreuth, Germany; (P.Z.); (O.M.)
- Department of Cardiology, Klinikum Bamberg, 96049 Bamberg, Germany;
| | - Felix Aberer
- Department of Sport Science, Division of Exercise Physiology and Metabolism, University of Bayreuth, 95447 Bayreuth, Germany; (P.Z.); (O.M.)
- Department of Endocrinology and Diabetology, Medical University of Graz, 8036 Graz, Austria;
- Correspondence: ; Tel.: +43-316-385-86113
| | - Martin Braun
- Department of Cardiology, Klinikum Bamberg, 96049 Bamberg, Germany;
| | - Harald Sourij
- Department of Endocrinology and Diabetology, Medical University of Graz, 8036 Graz, Austria;
| | - Othmar Moser
- Department of Sport Science, Division of Exercise Physiology and Metabolism, University of Bayreuth, 95447 Bayreuth, Germany; (P.Z.); (O.M.)
- Department of Endocrinology and Diabetology, Medical University of Graz, 8036 Graz, Austria;
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11
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Takla M, Edling CE, Zhang K, Saadeh K, Tse G, Salvage SC, Huang CL, Jeevaratnam K. Transcriptional profiles of genes related to electrophysiological function in Scn5a +/- murine hearts. Physiol Rep 2021; 9:e15043. [PMID: 34617689 PMCID: PMC8495800 DOI: 10.14814/phy2.15043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 11/24/2022] Open
Abstract
The Scn5a gene encodes the major pore-forming Nav 1.5 (α) subunit, of the voltage-gated Na+ channel in cardiomyocytes. The key role of Nav 1.5 in action potential initiation and propagation in both atria and ventricles predisposes organisms lacking Scn5a or carrying Scn5a mutations to cardiac arrhythmogenesis. Loss-of-function Nav 1.5 genetic abnormalities account for many cases of the human arrhythmic disorder Brugada syndrome (BrS) and related conduction disorders. A murine model with a heterozygous Scn5a deletion recapitulates many electrophysiological phenotypes of BrS. This study examines the relationships between its Scn5a+/- genotype, resulting transcriptional changes, and the consequent phenotypic presentations of BrS. Of 62 selected protein-coding genes related to cardiomyocyte electrophysiological or homeostatic function, concentrations of mRNA transcribed from 15 differed significantly from wild type (WT). Despite halving apparent ventricular Scn5a transcription heterozygous deletion did not significantly downregulate its atrial expression, raising possibilities of atria-specific feedback mechanisms. Most of the remaining 14 genes whose expression differed significantly between WT and Scn5a+/- animals involved Ca2+ homeostasis specifically in atrial tissue, with no overlap with any ventricular changes. All statistically significant changes in expression were upregulations in the atria and downregulations in the ventricles. This investigation demonstrates the value of future experiments exploring for and clarifying links between transcriptional control of Scn5a and of genes whose protein products coordinate Ca2+ regulation and examining their possible roles in BrS.
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Affiliation(s)
- Michael Takla
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- Christ’s CollegeUniversity of CambridgeCambridgeUK
| | | | - Kevin Zhang
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- School of MedicineImperial College LondonLondonUK
| | - Khalil Saadeh
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- Clinical SchoolUniversity of CambridgeCambridgeUK
| | - Gary Tse
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- Second Hospital of Tianjin Medical UniversityTianjinChina
| | | | - Christopher L.‐H. Huang
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- Department of BiochemistryUniversity of CambridgeCambridgeUK
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12
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Sigmundsson F, Kuchalik J, Fadl S, Holy M, Joelson A. The unique challenges of Brugada syndrome in spinal deformity surgery. INTERDISCIPLINARY NEUROSURGERY 2021. [DOI: 10.1016/j.inat.2021.101281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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13
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Monasky MM, Micaglio E, Locati ET, Pappone C. Evaluating the Use of Genetics in Brugada Syndrome Risk Stratification. Front Cardiovasc Med 2021; 8:652027. [PMID: 33969014 PMCID: PMC8096997 DOI: 10.3389/fcvm.2021.652027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/24/2021] [Indexed: 12/19/2022] Open
Abstract
The evolution of the current dogma surrounding Brugada syndrome (BrS) has led to a significant debate about the real usefulness of genetic testing in this syndrome. Since BrS is defined by a particular electrocardiogram (ECG) pattern, after ruling out certain possible causes, this disease has come to be defined more for what it is not than for what it is. Extensive research is required to understand the effects of specific individual variants, including modifiers, rather than necessarily grouping together, for example, “all SCN5A variants” when trying to determine genotype-phenotype relationships, because not all variants within a particular gene act similarly. Genetic testing, including whole exome or whole genome testing, and family segregation analysis should always be performed when possible, as this is necessary to advance our understanding of the genetics of this condition. All considered, BrS should no longer be considered a pure autosomal dominant disorder, but an oligogenic condition. Less common patterns of inheritance, such as recessive, X–linked, or mitochondrial may exist. Genetic testing, in our opinion, should not be used for diagnostic purposes. However, variants in SCN5A can have a prognostic value. Patients should be diagnosed and treated per the current guidelines, after an arrhythmologic examination, based on the presence of the specific BrS ECG pattern. The genotype characterization should come in a second stage, particularly in order to guide the familial diagnostic work-up. In families in which an SCN5A pathogenic variant is found, genetic testing could possibly contribute to the prognostic risk stratification.
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Affiliation(s)
| | - Emanuele Micaglio
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Emanuela T Locati
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Carlo Pappone
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
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Bellofiore C, Sapienza G, Markovic U, Del Fabro V, Romano A, Stagno F, Tamburino C, Mangiafico S, Di Raimondo F, Conticello C. Myeloma Patient With Brugada Syndrome and Successful Lenalidomide Treatment. CLINICAL LYMPHOMA MYELOMA & LEUKEMIA 2021; 21:e456-e459. [PMID: 33531286 DOI: 10.1016/j.clml.2020.12.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/17/2020] [Accepted: 12/21/2020] [Indexed: 10/22/2022]
Affiliation(s)
- Claudia Bellofiore
- Division of Hematology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy.
| | - Giuseppe Sapienza
- Division of Hematology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy
| | - Uros Markovic
- Division of Hematology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy
| | - Vittorio Del Fabro
- Division of Hematology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy
| | - Alessandra Romano
- Division of Hematology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy
| | - Fabio Stagno
- Division of Hematology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy
| | - Corrado Tamburino
- Division of Cardiology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy
| | - Sarah Mangiafico
- Division of Cardiology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy
| | - Francesco Di Raimondo
- Division of Hematology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy
| | - Concetta Conticello
- Division of Hematology, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele Catania, Catania, Italy
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15
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Zhao D, Liang B, Peng J, Tang L, Su R, Luo L, Deng B, Wang S. Long-term follow-up in patients with Brugada Syndrome in South China. Ann Noninvasive Electrocardiol 2021; 26:e12823. [PMID: 33417270 PMCID: PMC8164141 DOI: 10.1111/anec.12823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/16/2020] [Accepted: 11/24/2020] [Indexed: 11/30/2022] Open
Abstract
Objective To evaluate the presence of Brugada electrocardiogram (ECG) pattern, clinical characteristics, treatment, and long‐term prognosis of Brugada syndrome in southern Chinese population. Methods This prospective study consisted of a consecutive series of patients with diagnostic coved type I Brugada ECG pattern at baseline between January 2007 and February 2020. Histories of symptoms including ventricular tachycardia (VT)/ventricular fibrillation (VF) episode, syncope, and family history of Brugada Syndrome (BrS) or unexplained sudden cardiac death were collected. Electrophysiological study and implantable cardioverter‐defibrillator (ICD) were performed. All patients included in this study were followed up in the outpatient department every 6 months after baseline evaluation. Occurrences of syncope, VF, and sudden death were independently analyzed by two cardiologists. Results 45 (56.3%) patients were diagnosed with BrS. During a mean follow‐up of 7.9 ± 3.6 years, six patients had experienced documented VF/sudden cardiac death (SCD) or recurrent syncope. Two patients experienced episodes of syncope more than once. Two patients experienced onset of electrical storm with a total of 11 episodes of VF. There were 50% of these events occurring in fever status. One of patient with BrS died of SCD. Conclusion There was a very low prevalence of Brugada syndrome in southern Chinese population. The risk of arrhythmic events was low in asymptomatic patients. ICD was high effective in preventing SCD without adverse device outcome in long‐term follow‐up. Fever can lead to predispose to malignant arrhythmia, and aggressive treatment of febrile state in Brugada syndrome was recommended.
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Affiliation(s)
- Donghua Zhao
- First People's Hospital of Zhaoqing, Zhaoqing, China
| | - Bo Liang
- First People's Hospital of Zhaoqing, Zhaoqing, China
| | - Jian Peng
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Liangyu Tang
- First People's Hospital of Zhaoqing, Zhaoqing, China
| | - Rongbin Su
- First People's Hospital of Zhaoqing, Zhaoqing, China
| | - Lingli Luo
- First People's Hospital of Zhaoqing, Zhaoqing, China
| | - Bin Deng
- First People's Hospital of Zhaoqing, Zhaoqing, China
| | - Shuyuan Wang
- First People's Hospital of Zhaoqing, Zhaoqing, China
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16
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Rieder M, Castiglione A, Asatryan B, Odening KE. [Why do we need genetics in cardiac rhythmology?]. Herzschrittmacherther Elektrophysiol 2020; 31:394-400. [PMID: 32661562 DOI: 10.1007/s00399-020-00697-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 06/21/2020] [Indexed: 06/11/2023]
Abstract
A variety of arrhythmogenic cardiac diseases such as channelopathies and cardiomyopathies are caused by genetic alterations. In patients with these diseases, malignant arrhythmias or sudden cardiac death frequently manifest already during young adulthood. Early recognition, risk stratification and adequate therapy is therefore essential to avoid sudden cardiac death. This review summarizes the implications of genetic testing for diagnosis, risk stratification and therapy of patients with cardiac channelopathies (long-QT syndrome, short-QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia) and inherited cardiomyopathies (hypertrophic, dilatative or arrhythmogenic right ventricular cardiomyopathy).
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Affiliation(s)
- Marina Rieder
- Universitätsklinik für Kardiologie, Inselspital, Universitätsspital Bern, Freiburgstrasse 8, 3010, Bern, Schweiz
- Klinik für Kardiologie und Angiologie I, Universitäts-Herzzentrum Freiburg, Freiburg, Deutschland
| | - Alessandro Castiglione
- Universitätsklinik für Kardiologie, Inselspital, Universitätsspital Bern, Freiburgstrasse 8, 3010, Bern, Schweiz
- Klinik für Kardiologie und Angiologie I, Universitäts-Herzzentrum Freiburg, Freiburg, Deutschland
| | - Babken Asatryan
- Universitätsklinik für Kardiologie, Inselspital, Universitätsspital Bern, Freiburgstrasse 8, 3010, Bern, Schweiz
| | - Katja E Odening
- Universitätsklinik für Kardiologie, Inselspital, Universitätsspital Bern, Freiburgstrasse 8, 3010, Bern, Schweiz.
- Klinik für Kardiologie und Angiologie I, Universitäts-Herzzentrum Freiburg, Freiburg, Deutschland.
- Institut für Physiologie, Universität Bern, Bühlplatz 5, 3012, Bern, Schweiz.
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17
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Ryabykina GV. [ECG changes in COVID-19]. ACTA ACUST UNITED AC 2020; 60:16-22. [PMID: 33155954 DOI: 10.18087/cardio.2020.8.n1192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 06/30/2020] [Indexed: 11/18/2022]
Abstract
Aim To evaluate changes in 12-lead ECG in patients with coronavirus infection.Materials and methods This article describes signs of electrocardiographic right ventricular "stress" in patients with COVID-19. 150 ECGs of 75 COVID-19 patients were analyzed in the Institute of Cardiology of the National Medical Research Centre for Therapy and Preventive Medicine. The diagnosis was based on the clinical picture of community-acquired pneumonia, data of chest multispiral computed tomography, and a positive test for COVID-19. ECG was recorded both in 3-6 and in 12 leads. Signs of right ventricular (RV) stress, so-called systolic overload (high R and inverted TV1-3 and TII, III, aVF), and diastolic overload (RV wall hypertrophy and cavity dilatation; complete or incomplete right bundle branch block) were evaluated.Results The most common signs for impaired functioning of the right heart include emergence of the RV P wave phase (41.3 %), incomplete right bundle branch block (42.6 %), ECG of the SIQ IIITIII type (33.3 %) typical for thromboembolic complications, and signs of RV hypertrophy, primarily increased SV5-6 (14.7 %). These changes are either associated with signs of RV myocardial stress (16 %) or appear on the background of signs for diffuse hypoxia evident as tall, positive, sharp-ended T waves in most leads (28 %).Conclusion A conclusive, comprehensive assessment of the reversal of hemodynamic disorders and electrocardiographic dynamics in patients with COVID-19 will be possible later, when more data become available.
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Affiliation(s)
- G V Ryabykina
- National Medical Research Center for Cardiology, Moscow, Russia
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18
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Li X, Li Z, Wang DWW, Wang DW, Wang Y. A Novel Gain-of-Function KCND3 Variant Associated with Brugada Syndrome. Cardiology 2020; 145:623-632. [PMID: 32818936 DOI: 10.1159/000508033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/06/2020] [Indexed: 11/19/2022]
Abstract
Brugada syndrome (BrS) is a known cause of sudden cardiac death (SCD) characterized by abnormal electrocardiograms and fatal arrhythmias. The variants in KCND3 encoding the KV4.3 potassium-channel (the α-subunit of the Ito) have seldom been reported in BrS. This study aimed to identify novel KCND3 variants associated with BrS and elucidate BrS pathogenesis. High-depth targeted sequencing was performed and the electrophysiological properties of the variants were detected by whole-cell patch-clamp methods in a cultured-cell expressing system. The transcriptional levels of KV4.3 in different genotypes were studied by real-time PCR. Western blot was used to assess channel protein expression. A novel KCND3heterozygous variant, c.1292G>A (Arg431His, R431H), was found in the proband. Whole-cell patch-clamp results revealed a gain-of-function phenotype in the variant, with peak Ito current density increased and faster recovery from inactivation. The expression of mutant Kv4.3 membrane protein increased and the cytoplasmic protein decreased, demonstrating that the membrane/cytoplasm ratio was significantly different. In conclusion, a novel KCND3 heterozygous variant was associated with BrS. The increased Ito current explained the critical role of KCND3 in the pathogenesis of BrS. Genetic screening for KCND3 could be useful for understanding the pathogenesis of BrS and providing effective risk stratification in the clinic.
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Affiliation(s)
- Xianqing Li
- Division of Cardiology, Departments of Internal Medicine and Genetic Diagnosis Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Zongzhe Li
- Division of Cardiology, Departments of Internal Medicine and Genetic Diagnosis Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Dao Wen Wen Wang
- Division of Cardiology, Departments of Internal Medicine and Genetic Diagnosis Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Dao Wu Wang
- State Key Laboratory of Reproductive Medicine, the Center for Clinical Reproductive Medicine and Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yan Wang
- Division of Cardiology, Departments of Internal Medicine and Genetic Diagnosis Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, .,Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Huazhong University of Science and Technology, Wuhan, China,
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19
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The 10-Year Prognosis and Prevalence of Brugada-Type Electrocardiograms in Elderly Women: A Longitudinal Nationwide Community-Based Prospective Study. J Cardiovasc Nurs 2020; 35:E25-E32. [PMID: 32609463 PMCID: PMC7553189 DOI: 10.1097/jcn.0000000000000722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/30/2022]
Abstract
BACKGROUND Brugada syndrome is a disorder associated with sudden cardiac death and characterized by an abnormal electrocardiogram (ECG). Previous studies were predominantly conducted in men, and the data on long-term prognosis are limited. Information about women, especially elderly women, is lacking. OBJECTIVE The aim of this study was to investigate the long-term prognosis of the Brugada ECG pattern in elderly women. METHOD We investigated the 10-year prognosis of the Brugada ECG pattern in elderly women in a nationwide community-based population in Taiwan. Community-dwelling women older than 55 years were prospectively recruited from December 2008 to March 2013 by a stratified random sampling method. All enrolled individuals were followed up annually until April 2019, and the cause of death was documented by citizen death records. RESULTS Among 2597 women, 60 (2.31%) had a Brugada-type ECG, and this prevalence was higher than the mean global prevalence of 0.23%. One woman had a type 1 ECG (0.04%), whereas 15 (0.58%) and 44 (1.70%) women had type 2 and type 3 ECG patterns, respectively. Cox survival analysis revealed that all-cause mortality and cardiac mortality were similar in the individuals with and without a Brugada-type ECG during a mean follow-up of 96.1 ± 20.5 months. CONCLUSIONS Our findings suggest that Brugada ECG patterns are not infrequent in elderly women but are not associated with increased risk of mortality in long-term follow-up; these findings may help reduce unnecessary anxiety for physicians, nurses, allied health caregivers, and patients.
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20
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Brugada Syndrome – Report of Familial Occurrence Diagnosed in the Emergency Department. JOURNAL OF CARDIOVASCULAR EMERGENCIES 2020. [DOI: 10.2478/jce-2020-0001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Introduction: Brugada syndrome represents the clinical manifestation of a rare disease with genetic etiology. The syndrome is characterized by ventricular dysrhythmias associated with syncope or sudden cardiac death in the lack of any structural cardiac disease. The diagnosis of Brugada syndrome is established if a type 1 electrocardiographic (ECG) pattern of ST-segment and QRS morphology is present, in association with certain clinical manifestations and/or familial history.
Case presentation: A 31-year-old male patient, without any medical history, presented in the emergency department (ED) of a clinical center. His only complaints consisted in palpitations, chest discomfort, and emotional stress related to the recent death of his wife. Earlier on the same day, his wife, a 25-year-old female was brought via emergency medical services (EMS) to the ED after presenting ventricular fibrillation. The female patient presented a long term history of chest pain and one year prior to this episode she presented idiopathic ventricular fibrillation, for which she had undergone implantation of an automated cardioverter defibrillator. As the couple were cousins, the EMS specialist suspected the presence of a familial cardiac disorder. The electrocardiogram of the male patient revealed a coved-type ST-segment elevation of 4 mm in leads V1–V3 compatible with type 1 Brugada syndrome.
Conclusion: In case of Brugada syndrome, a genetic disorder associated with increased risk of SCD, the patient's first-degree relatives should be investigated as well, in order to identify the presence of the syndrome and to prevent SCD. As the sole established effective therapeutic measure for patients diagnosed with Brugada syndrome, ICD implantation should be considered in order to decrease the risk of syncope and SCD. This case is particular because a rare disease with familial etiology was identified in both husband and wife, who were cousins.
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21
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Vlachos K, Mascia G, Martin CA, Bazoukis G, Frontera A, Cheniti G, Letsas KP, Efremidis M, Georgopoulos S, Gkalapis C, Duchateau J, Parmbrun T, Derval N, Hocini M, Haissaguerre M, Jais P, Sacher F. Atrial fibrillation in Brugada syndrome: Current perspectives. J Cardiovasc Electrophysiol 2020; 31:975-984. [DOI: 10.1111/jce.14361] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Konstantinos Vlachos
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
| | - Giuseppe Mascia
- Cardiology and Electrophysiology UnitAzienda USL Toscana Florence Italy
| | - Claire A. Martin
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
- Department of Electrophysiology‐CardiologyRoyal Papworth Hospital Cambridge UK
| | - George Bazoukis
- Laboratory of Electrophysiology, Second Department of CardiologyGeneral Hospital of Athens “Evangelismos" Athens Greece
| | - Antonio Frontera
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
| | - Ghassen Cheniti
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
| | - Konstantinos P. Letsas
- Laboratory of Electrophysiology, Second Department of CardiologyGeneral Hospital of Athens “Evangelismos" Athens Greece
| | - Micheal Efremidis
- Laboratory of Electrophysiology, Second Department of CardiologyGeneral Hospital of Athens “Evangelismos" Athens Greece
| | - Stamatis Georgopoulos
- Laboratory of Electrophysiology, Second Department of CardiologyGeneral Hospital of Athens “Evangelismos" Athens Greece
| | - Charis Gkalapis
- Department of Electrophysiology‐CardiologyKlinikum Vest Recklinghausen Germany
- Department of Cardiology, Akademisches LehrkrankenhausRuhr‐Universität Bochum Bochum Germany
| | - Josselin Duchateau
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
| | - Thomas Parmbrun
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
| | - Nicholas Derval
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
| | - Mélèze Hocini
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
| | - Michel Haissaguerre
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
| | - Pierre Jais
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
| | - Frédéric Sacher
- Hôpital Cardiologique du Haut LévèqueCHU de Bordeaux and IHU‐LIRYC Pessac France
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22
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Romero D, Behar N, Petit B, Probst V, Sacher F, Mabo P, Hernández AI. Dynamic changes in ventricular depolarization during exercise in patients with Brugada syndrome. PLoS One 2020; 15:e0229078. [PMID: 32126115 PMCID: PMC7053736 DOI: 10.1371/journal.pone.0229078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 01/29/2020] [Indexed: 11/18/2022] Open
Abstract
Brugada syndrome (BS) is a genetic pathological condition associated with a high risk for sudden cardiac death (SCD). Ventricular depolarization disorders have been suggested as a potential electrophysiological mechanism associated with high SCD risk on patients with BS. This paper aims to characterize the dynamic changes of ventricular depolarization observed during physical exercise in symptomatic and asymptomatic BS patients. To this end, cardiac ventricular depolarization features were automatically extracted from 12-lead ECG recordings acquired during standardized exercise stress test in 110 BS patients, of whom 25 were symptomatic. Conventional parameters were evaluated, including QRS duration, R and S wave amplitudes ( AR, AS), as well as QRS morphological features, such as up-stroke and down-stroke slopes of the R and S waves ( UR, DR and US). The effects of physical exercise and recovery on the dynamics of these markers were assessed in both BS populations. Features showing significantly different dynamics between the studied groups were used alone and in combination with the clinical characteristics of the patients in a logistic regression analysis. Results show larger changes in the second half of the QRS complex through AS and US measured in the right precordial leads for asymptomatic patients, especially during recovery, when the vagal tone is more pronounced. Multivariate analysis involving both types of features resulted in a reduced model of three relevant features ( ΔAS in lead V2, Sex and heart rate recovery, HRR), which achieved a suitable discrimination performance between groups; sensitivity = 80% and specificity = 75% (AUC = 83%). However, after controlling the model for possible confounding factors, only one feature ( ΔAS) remained meaningful. This adjusted model significantly improved the overall discrimination performance by up to: sensitivity = 84% and specificity = 100% (AUC = 94%). The study highlights the importance of physical exercise test to unmask differentiated behaviors between symptomatic and asymptomatic BS patients through depolarization dynamic analysis. This analysis together with the obtained model may help to identify asymptomatic patients at low or high risk of future cardiac events, but it should be confirmed by further prospective studies.
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Affiliation(s)
- Daniel Romero
- Univ Rennes, CHU Rennes, Inserm, LTSI - UMR 1099, Rennes, France
| | - Nathalie Behar
- Univ Rennes, CHU Rennes, Inserm, LTSI - UMR 1099, Rennes, France
| | - Bertrand Petit
- Service Cardiologie, GH Sud. Saint Pierre La Réunion, Saint-Pierre, France
| | | | | | - Philippe Mabo
- Univ Rennes, CHU Rennes, Inserm, LTSI - UMR 1099, Rennes, France
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Garris R, Vasudev R, Gupta P, Tiyyagura S, Shamoon F, Bikkina M. Brugada syndrome & AKAP9: Reconciling clinical findings with diagnostic uncertainty. J Electrocardiol 2019; 57:119-121. [PMID: 31654968 DOI: 10.1016/j.jelectrocard.2019.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/30/2019] [Accepted: 09/05/2019] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Brugada Syndrome typically presents with sudden nocturnal arrhythmias. Diagnosis may be challenging due to variable and transient electrocardiogram patterns and nondiagnostic provocation studies. Genetic testing can establish the etiology, but results may be inconclusive with variants of uncertain significance. CASE A 24-year-old male with family history of sudden cardiac death was found unresponsive due to seizure. He was hemodynamically stable. ECG showed saddle-back ST elevations in V1 and V2. Procainamide challenge was negative. We subsequently performed genetic testing, which demonstrated AKAP9 variant. DISCUSSION AKAP9 is a scaffolding protein that facilitates phosphorylation of delayed-rectifier potassium channels. The AKAP9 variant alters potassium current causing disordered repolarization and ventricular reentry. It has been previously linked to other channelopathies, but its pathogenicity is fully undetermined. CONCLUSION Genetic testing is a useful tool to determine the origin of channelopathy, but inconclusive results with variants of uncertain significance should be clinically correlated.
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Affiliation(s)
- Rana Garris
- Department of Internal Medicine, St. Joseph's Health, New York Medical College, Paterson, NJ, USA.
| | - Rahul Vasudev
- Department of Cardiology, St. Joseph's Health, New York Medical College, Paterson, NJ, USA
| | - Punita Gupta
- Department of Genetics, St. Joseph's Health, Paterson, NJ, USA.
| | - Satish Tiyyagura
- Department of Cardiology, St. Joseph's Health, New York Medical College, Paterson, NJ, USA; Department of Electrophysiology, St. Joseph's Health, Paterson, NJ, USA.
| | - Fayez Shamoon
- Department of Cardiology, St. Joseph's Health, New York Medical College, Paterson, NJ, USA.
| | - Mahesh Bikkina
- Department of Cardiology, St. Joseph's Health, New York Medical College, Paterson, NJ, USA.
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24
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Lin CY, Lin YJ, Li CH, Chung FP, Lo MT, Lin C, Chang HC, Chang SL, Lo LW, Hu YF, Chang YT, Lin CH, Chen YY, Walia R, Te ALD, Yamada S, Wu TJ, Chen SA. Heterogeneous distribution of substrates between the endocardium and epicardium promotes ventricular fibrillation in arrhythmogenic right ventricular dysplasia/cardiomyopathy. Europace 2018; 20:501-511. [PMID: 28082418 DOI: 10.1093/europace/euw393] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/08/2016] [Indexed: 11/12/2022] Open
Abstract
Aims Whether the distribution of scar in arrhythmogenic right ventricular cardiomyopathy (ARVC) plays a role in predicting different types of ventricular arrhythmias is unknown. This study aimed to investigate the prognostic value of scar distribution in patients with ARVC. Methods and results We studied 80 consecutive ARVC patients (46 men, mean age 47 ± 15 years) who underwent an electrophysiological study with ablation. Thirty-four patients receive both endocardial and epicardial mapping. Abnormal endocardial substrates and epicardial substrates were characterized. Three groups were defined according to the epicardial and endocardial scar gradient (<10%: transmural, 10-20%: intermediate, >20%: horizontal, as groups 1, 2, and 3, respectively). Sinus rhythm electrograms underwent a Hilbert-Huang spectral analysis and were displayed as 3D Simultaneous Amplitude Frequency Electrogram Transformation (SAFE-T) maps, which represented the arrhythmogenic potentials. The baseline characteristics were similar between the three groups. Group 3 patients had a higher incidence of fatal ventricular arrhythmias requiring defibrillation and cardiac arrest during the initial presentation despite having fewer premature ventricular complexes. A larger area of arrhythmogenic potentials in the epicardium was observed in patients with horizontal scar. The epicardial-endocardial scar gradient was independently associated with the occurrence of fatal ventricular arrhythmias after a multivariate adjustment. The total, ventricular tachycardia, and VF recurrent rates were higher in Group 3 during 38 ± 21 months of follow-up. Conclusion For ARVC, the epicardial substrate that extended in the horizontal plane rather than transmurally provided the arrhythmogenic substrate for a fatal ventricular arrhythmia circuit.
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Affiliation(s)
- Chin-Yu Lin
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan.,Department of Medicine, Taipei Veterans General Hospital, Yuanshan Branch, Yilan, Taiwan
| | - Yenn-Jiang Lin
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Cheng-Hung Li
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan.,Division of Cardiology, Cardiovascular Center, Taichung Veterans General Hospital, Taiwan
| | - Fa-Po Chung
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Men-Tzung Lo
- Department of Biomedical Sciences and Engineering, Institute of Translational and Interdisciplinary Medicine, National Central University, Taipei, Taiwan
| | - Chen Lin
- Department of Biomedical Sciences and Engineering, Institute of Translational and Interdisciplinary Medicine, National Central University, Taipei, Taiwan
| | - Hsiang-Chih Chang
- Department of Biomedical Sciences and Engineering, Institute of Translational and Interdisciplinary Medicine, National Central University, Taipei, Taiwan
| | - Shih-Lin Chang
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Li-Wei Lo
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Yu-Feng Hu
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Yao-Ting Chang
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Chung-Hsing Lin
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Yun-Yu Chen
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Institute of Epidemiology and Preventive Medicine College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Rohit Walia
- Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Abigail Louise D Te
- Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Shinya Yamada
- Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
| | - Tsu-Juey Wu
- Division of Cardiology, Cardiovascular Center, Taichung Veterans General Hospital, Taiwan
| | - Shih-Ann Chen
- Faculty of Medicine, Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taiwan.,Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taiwan
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25
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Inherited primary arrhythmia disorders: cardiac channelopathies and sports activity. Herz 2018; 45:142-157. [PMID: 29744527 DOI: 10.1007/s00059-018-4706-2] [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] [Received: 01/28/2018] [Revised: 03/25/2018] [Accepted: 04/14/2018] [Indexed: 01/02/2023]
Abstract
Sudden cardiac death (SCD) in an apparently healthy individual is a tragedy. It is important to identify the cause of death and to prevent SCD in potentially at-risk family members. Inherited primary arrhythmia disorders are associated with exercise-related SCD. Despite the well-known benefits of exercise, exercise restriction has been a historical mainstay of therapy for these conditions. However, since familiarity with inherited arrhythmia conditions has increased and patients are often children and young adults, it is necessary to reassess the treatment guidelines regarding exercise constraints. The aim of this review is to analyze the risk of exercise-induced SCD in patients with inherited cardiac conditions and explore the challenges faced when advising patients about exercise limitations. We searched for publications on cardiac channelopathies in PubMed with the following medical subject headings (MeSH): "long QT syndrome"; "short QT syndrome"; "Brugada syndrome"; and "catecholaminergic polymorphic ventricular tachycardia". The abstracts of these articles were scanned, and articles of relevance, along with pertinent references, were read in full. The analysis was restricted to reports published in English. The findings of this analysis suggest that exercise with low-to-moderate cardiovascular demand may be possible under regular clinical follow-up in inherited primary arrhythmia disorders. Recent data show that patients with inherited primary arrhythmia disorders are at low risk for events once a comprehensive treatment program has been established. Recreational activity is likely safe for these individuals, with personalized management based on individual patient preferences and priorities.
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26
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Selga E, Sendfeld F, Martinez-Moreno R, Medine CN, Tura-Ceide O, Wilmut SI, Pérez GJ, Scornik FS, Brugada R, Mills NL. Sodium channel current loss of function in induced pluripotent stem cell-derived cardiomyocytes from a Brugada syndrome patient. J Mol Cell Cardiol 2018; 114:10-19. [PMID: 29024690 PMCID: PMC5807028 DOI: 10.1016/j.yjmcc.2017.10.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 09/15/2017] [Accepted: 10/04/2017] [Indexed: 12/24/2022]
Abstract
Brugada syndrome predisposes to sudden death due to disruption of normal cardiac ion channel function, yet our understanding of the underlying cellular mechanisms is incomplete. Commonly used heterologous expression models lack many characteristics of native cardiomyocytes and, in particular, the individual genetic background of a patient. Patient-specific induced pluripotent stem (iPS) cell-derived cardiomyocytes (iPS-CM) may uncover cellular phenotypical characteristics not observed in heterologous models. Our objective was to determine the properties of the sodium current in iPS-CM with a mutation in SCN5A associated with Brugada syndrome. Dermal fibroblasts from a Brugada syndrome patient with a mutation in SCN5A (c.1100G>A, leading to Nav1.5_p.R367H) were reprogrammed to iPS cells. Clones were characterized and differentiated to form beating clusters and sheets. Patient and control iPS-CM were structurally indistinguishable. Sodium current properties of patient and control iPS-CM were compared. These results were contrasted with those obtained in tsA201 cells heterologously expressing sodium channels with the same mutation. Patient-derived iPS-CM showed a 33.1-45.5% reduction in INa density, a shift in both activation and inactivation voltage-dependence curves, and faster recovery from inactivation. Co-expression of wild-type and mutant channels in tsA201 cells did not compromise channel trafficking to the membrane, but resulted in a reduction of 49.8% in sodium current density without affecting any other parameters. Cardiomyocytes derived from iPS cells from a Brugada syndrome patient with a mutation in SCN5A recapitulate the loss of function of sodium channel current associated with this syndrome; including pro-arrhythmic changes in channel function not detected using conventional heterologous expression systems.
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Affiliation(s)
- Elisabet Selga
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Franziska Sendfeld
- Scottish Centre for Regenerative Medicine, University of Edinburgh, United Kingdom; BHF/University Centre for Cardiovascular Sciences, University of Edinburgh, United Kingdom
| | - Rebecca Martinez-Moreno
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Claire N Medine
- Scottish Centre for Regenerative Medicine, University of Edinburgh, United Kingdom; BHF/University Centre for Cardiovascular Sciences, University of Edinburgh, United Kingdom
| | - Olga Tura-Ceide
- Department of Pulmonary Medicine, Hospital Clinic-Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, University of Barcelona, Spain
| | - Sir Ian Wilmut
- Scottish Centre for Regenerative Medicine, University of Edinburgh, United Kingdom
| | - Guillermo J Pérez
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Fabiana S Scornik
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Ramon Brugada
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Hospital Josep Trueta, Girona, Spain
| | - Nicholas L Mills
- BHF/University Centre for Cardiovascular Sciences, University of Edinburgh, United Kingdom.
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Choi YF, Siu AYC, Wong TW, Lau CC. ST Elevation is not Always Equivalent to Acute Myocardial Infarction: a Case of Brugada Syndrome. HONG KONG J EMERG ME 2017. [DOI: 10.1177/102490790301000209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Acute myocardial infarction (AMI) is one of the most alerting situations in emergency department. Electrocardiogram (ECG) is one of the most important diagnostic tools and the decision about thrombolytic therapy is usually based upon ECG findings when clinically suspicious. However, ST segment elevation is not always equivalent to acute myocardial infarction. We present a rare syndrome whose ECG shows persistent ST elevation not related to AMI.
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Affiliation(s)
- YF Choi
- Pamela Youde Nethersole Eastern Hospital, Accident and Emergency Department, 3 Lok Man Road, Chaiwan, Hong Kong
| | - AYC Siu
- North District Hospital, Accident and Emergency Department, 9 Po Kin Road, Sheung Shui, N.T., Hong Kong
| | - TW Wong
- Pamela Youde Nethersole Eastern Hospital, Accident and Emergency Department, 3 Lok Man Road, Chaiwan, Hong Kong
| | - CC Lau
- Pamela Youde Nethersole Eastern Hospital, Accident and Emergency Department, 3 Lok Man Road, Chaiwan, Hong Kong
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28
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Affiliation(s)
- Sukhjinder S Nijjer
- Consultant in Interventional Cardiology, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London
| | - Vishal Luther
- BHF Clinical Research Fellow and Cardiology Specialist Registrar, Augustus Waller Department of Electrophysiology, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London W12 0HS
| | - David C Lefroy
- Consultant in Cardiology and Cardiac Electrophysiology, Augustus Waller Department of Electrophysiology, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London
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29
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Nakamura R, Nishizaki M, Lee K, Shimizu M, Fujii H, Yamawake N, Sakurada H, Hiraoka M, Isobe M. Life-Threatening Ventricular Arrhythmia and Brugada-Type ST-Segment Elevation Associated With Acute Ischemia of the Right Ventricular Outflow Tract. Circ J 2017; 81:322-329. [DOI: 10.1253/circj.cj-16-1112] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Rena Nakamura
- Department of Cardiology, Yokohama Minami Kyosai Hospital
| | | | - Kiko Lee
- Department of Cardiology, Yokohama Minami Kyosai Hospital
| | - Masato Shimizu
- Department of Cardiology, Yokohama Minami Kyosai Hospital
| | - Hiroyuki Fujii
- Department of Cardiology, Yokohama Minami Kyosai Hospital
| | | | - Harumizu Sakurada
- Tokyo Metropolitan Health and Medical Treatment Corporation Ohkubo Hospital
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30
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Enriquez A, Antzelevitch C, Bismah V, Baranchuk A. Atrial fibrillation in inherited cardiac channelopathies: From mechanisms to management. Heart Rhythm 2016; 13:1878-84. [DOI: 10.1016/j.hrthm.2016.06.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Indexed: 10/21/2022]
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31
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Sorajja D, Ramakrishna H, Poterack AK, Shen WK, Mookadam F. Brugada syndrome and its relevance in the perioperative period. Ann Card Anaesth 2016; 18:403-13. [PMID: 26139749 PMCID: PMC4881698 DOI: 10.4103/0971-9784.159812] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Brugada syndrome is an autosomal dominant genetic disorder associated with an increased risk of sudden cardiac death, as well as ventricular tachyarrhythmias. The defective cardiac sodium channels result in usual electrocardiographic findings of a coved-type ST elevation in precordial leads V1 to V3. The majority of patients have uncomplicated courses with anesthesia, surgery, and invasive procedures. However there is risk of worsening ST elevation and ventricular arrhythmias due to perioperative medications, surgical insult, electrolyte abnormalities, fever, autonomic nervous system tone, as well as other perturbations. Given the increasing numbers of patients with inherited conduction disorders presenting for non-cardiac surgery that are at risk of sudden cardiac death, safe anesthetic management depends upon a detailed knowledge of these conditions.
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Affiliation(s)
| | | | | | | | - Farouk Mookadam
- Department of Anesthesiology, Mayo Clinic, Arizona, AZ 85259, USA
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32
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Jeevaratnam K, Guzadhur L, Goh YM, Grace AA, Huang CLH. Sodium channel haploinsufficiency and structural change in ventricular arrhythmogenesis. Acta Physiol (Oxf) 2016; 216:186-202. [PMID: 26284956 DOI: 10.1111/apha.12577] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 06/11/2015] [Accepted: 07/24/2015] [Indexed: 12/19/2022]
Abstract
Normal cardiac excitation involves orderly conduction of electrical activation and recovery dependent upon surface membrane, voltage-gated, sodium (Na(+) ) channel α-subunits (Nav 1.5). We summarize experimental studies of physiological and clinical consequences of loss-of-function Na(+) channel mutations. Of these conditions, Brugada syndrome (BrS) and progressive cardiac conduction defect (PCCD) are associated with sudden, often fatal, ventricular tachycardia (VT) or fibrillation. Mouse Scn5a(+/-) hearts replicate important clinical phenotypes modelling these human conditions. The arrhythmic phenotype is associated not only with the primary biophysical change but also with additional, anatomical abnormalities, in turn dependent upon age and sex, each themselves exerting arrhythmic effects. Available evidence suggests a unified binary scheme for the development of arrhythmia in both BrS and PCCD. Previous biophysical studies suggested that Nav 1.5 deficiency produces a background electrophysiological defect compromising conduction, thereby producing an arrhythmic substrate unmasked by flecainide or ajmaline challenge. More recent reports further suggest a progressive decline in conduction velocity and increase in its dispersion particularly in ageing male Nav 1.5 haploinsufficient compared to WT hearts. This appears to involve a selective appearance of slow conduction at the expense of rapidly conducting pathways with changes in their frequency distributions. These changes were related to increased cardiac fibrosis. It is thus the combination of the structural and biophysical changes both accentuating arrhythmic substrate that may produce arrhythmic tendency. This binary scheme explains the combined requirement for separate, biophysical and structural changes, particularly occurring in ageing Nav 1.5 haploinsufficient males in producing clinical arrhythmia.
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Affiliation(s)
- K. Jeevaratnam
- Faculty of Health and Medical Science; University of Surrey; Guilford UK
- Perdana University - Royal College of Surgeons Ireland; Serdang Selangor Darul Ehsan Malaysia
| | - L. Guzadhur
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
- Niche Science & Technology; Richmond UK
| | - Y. M. Goh
- Department of Preclinical Sciences; Faculty of Veterinary Medicine; University Putra Malaysia; Serdang Selangor Darul Ehsan Malaysia
| | - A. A. Grace
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
| | - C. L.-H. Huang
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
- Physiological Laboratory; University of Cambridge; Cambridge UK
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Korte AKM, Derde L, van Wijk J, Tjan DH. Sudden cardiac arrest as a presentation of Brugada syndrome unmasked by thyroid storm. BMJ Case Rep 2015; 2015:bcr-2015-212351. [PMID: 26718704 DOI: 10.1136/bcr-2015-212351] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
An 18-year-old man suffered a sudden cardiac arrest with ventricular fibrillation and was successfully resuscitated. He had neither a medical nor family history of cardiac disease/sudden death, but was known to have Graves' disease, for which he was treated with radioactive iodine. Recently, block-and-replacement therapy had been discontinued to evaluate thyroid functioning. On admission, thyroid hormone levels were markedly elevated, suggesting thyroid storm due to residual Graves' disease. The patient was treated with propylthiouracil, hydrocortisone and Lugol solution. ECG showed repolarisation patterns suggestive of an underlying type 1 Brugada syndrome (BS). These findings were confirmed by an additional ajmaline test. An implantable cardioverter defibrillator was implanted to prevent future arrhythmias. The patient underwent total thyroidectomy 9 months later and recovered completely. To the best of our knowledge, this is the first reported case of a sudden cardiac arrest as a presentation of BS unmasked by thyroid storm.
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Affiliation(s)
- Anna K M Korte
- Department of Pulmonary Medicine, St Antonius Hospital, Nieuwegein, The Netherlands
| | - Lennie Derde
- Department of Intensive Care, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Jeroen van Wijk
- Department of Internal Medicine, Gelderse Vallei Hospital, Ede, The Netherlands
| | - David H Tjan
- Department of Intensive Care, Gelderse Vallei Hospital, Ede, The Netherlands
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Ali A, Butt N, Sheikh AS. Early repolarization syndrome: A cause of sudden cardiac death. World J Cardiol 2015; 7:466-75. [PMID: 26322186 PMCID: PMC4549780 DOI: 10.4330/wjc.v7.i8.466] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/18/2015] [Accepted: 06/01/2015] [Indexed: 02/06/2023] Open
Abstract
Early repolarization syndrome (ERS), demonstrated as J-point elevation on an electrocardiograph, was formerly thought to be a benign entity, but the recent studies have demonstrated that it can be linked to a considerable risk of life - threatening arrhythmias and sudden cardiac death (SCD). Early repolarization characteristics associated with SCD include high - amplitude J-point elevation, horizontal and/or downslopping ST segments, and inferior and/or lateral leads location. The prevalence of ERS varies between 3% and 24%, depending on age, sex and J-point elevation (0.05 mV vs 0.1 mV) being the main determinants. ERS patients are sporadic and they are at a higher risk of having recurrent cardiac events. Implantable cardioverter-defibrillator implantation and isoproterenol are the suggested therapies in this set of patients. On the other hand, asymptomatic patients with ERS are common and have a better prognosis. The risk stratification in asymptomatic patients with ERS still remains a grey area. This review provides an outline of the up-to-date evidence associated with ERS and the risk of life - threatening arrhythmias. Further prospective studies are required to elucidate the mechanisms of ventricular arrhythmogenesis in patients with ERS.
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Affiliation(s)
- Abdi Ali
- Abdi Ali, Nida Butt, Core Medical Trainees, Wrexham Maelor Hospital, Wrexham, Wales LL13 7TZ, United Kingdom
| | - Nida Butt
- Abdi Ali, Nida Butt, Core Medical Trainees, Wrexham Maelor Hospital, Wrexham, Wales LL13 7TZ, United Kingdom
| | - Azeem S Sheikh
- Abdi Ali, Nida Butt, Core Medical Trainees, Wrexham Maelor Hospital, Wrexham, Wales LL13 7TZ, United Kingdom
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35
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You T, Mao W, Cai B, Li F, Xu H. Two novel Brugada syndrome-associated mutations increase KV4.3 membrane expression and function. Int J Mol Med 2015; 36:309-15. [PMID: 26016905 PMCID: PMC4494594 DOI: 10.3892/ijmm.2015.2223] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 04/28/2015] [Indexed: 11/06/2022] Open
Abstract
The human cardiac fast transient outward K+ channel is composed of the KV4.3 α subunit encoded by KCND3 and the K+ channel‑interacting protein 2 (KChIP2) β subunit, and determines the early repolarization of the action potential (AP). Two human mutations (G600R and L450F) in KV4.3 are associated with Brugada syndrome and they increase the KV4.3/KChIP2‑encoded fast transient outward K+ current (Ito,f) and cause the stable loss of the AP dome. However, the detailed mechanisms underlying the gain of Ito,f function by these two mutations are largely unknown. The experiments in the present study were undertaken to investigate the effect of these mutations and the underlying mechanism. Whole cell patch‑clamp recording was performed in HEK‑293 cells expressing KV4.3‑wild‑type (WT) and KV4.3 mutants with KChIP2. The two individual mutant‑encoded currents were significantly increased but the kinetics of the channels affected by the two mutations were different. The two mutations slowed KV4.3/KChIP2‑encoded channel inactivation; they did not increase the recovery from the KV4.3/KChIP2‑encoded channel inactivation. Western blotting showed that total KV4.3 protein was significantly augmented in HEK‑293 cells expressing the two individual mutants with KChIP2. Furthermore, immunofluorescence confocal microscopy demonstrated that the KV4.3 channel protein was expressed more in the cell membrane compared to the cytoplasm in cells that expressed individual mutants with KChIP2. Also, KChIP2 increased the amount of channel protein in the cell membrane of KV4.3 mutants significantly more than KV4.3‑WT. Reverse transcription‑polymerase chain reaction showed that KV4.3 mRNA was not significantly changed by individual mutations in the presence of KChIP2. Taken together, the present study revealed that the mutations cause a gain‑of‑function of KV4.3/KChIP2‑encoded channels by increasing membrane protein expression and slowing channel inactivation.
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Affiliation(s)
- Tao You
- Department of Cardiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - Weike Mao
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Benzhi Cai
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Faqian Li
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Haodong Xu
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
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Patocskai B, Antzelevitch C. Novel Therapeutic Strategies for the Management of Ventricular Arrhythmias Associated with the Brugada Syndrome. Expert Opin Orphan Drugs 2015; 3:633-651. [PMID: 27559494 PMCID: PMC4993532 DOI: 10.1517/21678707.2015.1037280] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Brugada syndrome (BrS) is an inherited cardiac arrhythmia syndrome characterized by prominent J waves appearing as distinct coved type ST segment elevation in the right precordial leads of the ECG. It is associated with a high risk for sudden cardiac death. AREAS COVERED We discuss 1) ECG manifestations of BrS which can be unmasked or aggravated by sodium channel blockers, febrile states, vagotonic agents, as well as tricyclic and tetracyclic antidepressants; 2) Genetic basis of BrS; 3) Ionic and cellular mechanisms underlying BrS; 4) Therapy involving devices including an implantable cardioverter defibrillator (ICD); 5) Therapy involving radiofrequency ablation; and 6) Therapy involving pharmacological therapy which is aimed at producing an inward shift in the balance of the currents active during phase 1 of the right ventricular action potential either by boosting calcium channel current (isoproterenol, cilostazol and milrinone) or by inhibition of transient outward current Ito (quinidine, bepridil and the Chinese herb extract Wenxin Keli). EXPERT OPINION This review provides an overview of the clinical and molecular aspects of BrS with a focus on approaches to therapy. Available data suggest that agents capable of inhibiting the transient outward current Ito can exert an ameliorative effect regardless of the underlying cause.
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Affiliation(s)
- Bence Patocskai
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
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37
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Abstract
Brugada syndrome is responsible for up to 4% of all sudden cardiac deaths worldwide and up to 20% of sudden cardiac deaths in patients with structurally normal hearts. Heterogeneity of repolarization and depolarization, particularly over the right ventricle and the outflow tract, is responsible for the arrhythmogenic substrate. The coved Type I ECG pattern is considered diagnostic of the syndrome but its prevalence is very low. Distinguishing between a saddle back Type 2 Brugada pattern and one of many "Brugada-like" patterns presents challenges especially in athletes. A number of criteria have been proposed to assess Brugada ECG patterns. Proper precordial ECG lead placement is paramount. This paper reviews Brugada syndrome, Brugada ECG patterns, and recently proposed criteria. Recommendations for evaluating a Brugada ECG pattern are provided.
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Affiliation(s)
- Eugene H Chung
- Division of Cardiology, Cardiac Electrophysiology, UNC School of Medicine, 160 Dental Circle, CB 7075, Chapel Hill, NC.
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38
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Makarawate P, Chaosuwannakit N, Vannaprasaht S, Tassaneeyakul W, Sawanyawisuth K. Clinical characteristics and treatment outcomes of patients with Brugada syndrome in northeastern Thailand. Singapore Med J 2015; 55:217-20. [PMID: 24763838 DOI: 10.11622/smedj.2014055] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Brugada syndrome (BrS) is a common genetic cause of sudden cardiac arrest (SCA) due to polymorphic ventricular tachycardia and ventricular fibrillation. The current recommended therapy for high-risk BrS patients is the use of an implantable cardioverter defibrillator (ICD). The present study aimed to report the clinical characteristics and treatment outcomes of BrS patients in northeastern Thailand. METHODS Patients who were diagnosed with BrS or had a Brugada electrocardiogram (ECG) between 2005 and 2012 at Khon Kaen University's hospitals were enrolled in the present study. Patients' clinical characteristics, ECG type, laboratory results and treatment were reviewed. RESULTS A total of 90 eligible patients were enrolled. Of these, 79 (87.8%) patients were symptomatic--65 (82.3%) had documented SCA and 14 (17.7%) had unexplained syncope. The remaining 11 (12.2%) patients were asymptomatic with Brugada ECG. A majority of the patients enrolled were born in northeastern Thailand. The mean age of the symptomatic patients was 44.49 ± 8.55 years. Among the symptomatic patients, a majority were male (n = 77, 97.5%) and 23 (29.1%) patients had a family history of SCA. Almost all BrS patients who were symptomatic (96.2%) received ICD treatment for secondary prevention. The number of patients who received appropriate ICD therapy was 4.2 times of those who received inappropriate shocks. Only 3 (3.8%) symptomatic BrS patients refused ICD treatment. CONCLUSION Clinical characteristics did not distinguish between symptomatic BrS patients and asymptomatic patients with Brugada ECGs. The clinical characteristics and treatment outcomes for the symptomatic BrS patients with SCA and unexplained syncope were similar. Among the BrS patients implanted with secondary prevention ICD in Northeastern Thailand, nearly one-third had received appropriate ICD therapy, far exceeding the incidence of device-related complications and inappropriate therapy.
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Affiliation(s)
| | | | | | | | - Kittisak Sawanyawisuth
- Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
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39
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Abstract
Brugada syndrome is an example of a channelopathy caused by an alteration in the transmembrane ion currents that together constitute the cardiac action potential. Approximately 20% of the cases of Brugada syndrome have been shown to be associated with mutations in the gene coding for the sodium ion channel in the cell membranes of the muscle cells of the heart. Patients with Brugada syndrome are prone to develop ventricular tachyarrhythmias that may lead to syncope, cardiac arrest or sudden cardiac death. Many clinical situations have been reported to unmask or exacerbate the electrocardiography (ECG) pattern of Brugada syndrome. Genetic testing for Brugada syndrome is clinically available. Here we report two cases of Brugada syndrome followed by a comprehensive review of the literature.
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Affiliation(s)
- Azeem S Sheikh
- Royal Glamorgan Hospital, Ynysmaerdy, Llantrisant, Pontyclun, UK
| | - Kula Ranjan
- Newham University Hospital NHS Trust, London, UK
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40
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Sethi KK, Sethi K, Chutani SK. Early repolarisation and J wave syndromes. Indian Heart J 2014; 66:443-52. [PMID: 25173204 PMCID: PMC4150048 DOI: 10.1016/j.ihj.2014.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 06/16/2014] [Indexed: 12/21/2022] Open
Abstract
J wave syndrome has emerged as a significant cause of Idiopathic ventricular fibrillation (IVF) responsible for sudden cardiac death. A large body of data is now available on genesis, genetics and ionic mechanisms of J wave syndromes. Two of these viz., Early repolarization syndrome (ER) and Brugada syndrome (BrS) are fairly well characterized enabling correct diagnosis in most patients. The first part of repolarization of ventricular myocardium is governed by Ito current i.e., rapid outward potassium current. The proposed mechanism of ventricular fibrillation (VF) and ventricular tachycardia (VT) storms is the faster Ito current in the epicardium than in the endocardium results in electrical gradient that forms the substrate for phase 2 reentry. Prevention of Ito current with quinidine supports this mechanism. Majority of ER patterns in young patients are benign. The key issue is to identify those at increased risk of sudden cardiac death. Association of both ER syndrome and Brugada syndrome with other disease states like coronary artery disease has also been reported. Individuals resuscitated from VF definitely need an implantable cardiac defibrillator (ICD) but in others there is no consensus regarding therapy. Role of electrophysiology study to provoke ventricular tachycardia or fibrillation is not yet well defined. Radiofrequency ablation of epicardial substrate in right ventricle in Brugada syndrome is also under critical evaluation. In this review we shall discuss historical features, epidemiology, electrocardiographic features, ionic pathogenesis, clinical features and current status of proposed treatment of ER and BrS.
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Affiliation(s)
- Kamal K Sethi
- Director of Cardiology, Division of Cardiology and Cardiac Electrophysiology, Delhi Heart & Lung Institute, 3 MM II, Panchkuian Road, New Delhi 110 055, India.
| | - Kabir Sethi
- Division of Cardiology and Cardiac Electrophysiology, Delhi Heart & Lung Institute, 3 MM II, Panchkuian Road, New Delhi 110 055, India
| | - Surendra K Chutani
- Division of Cardiology and Cardiac Electrophysiology, Delhi Heart & Lung Institute, 3 MM II, Panchkuian Road, New Delhi 110 055, India
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Choudhuri I, Pinninti M, Marwali MR, Sra J, Akhtar M. Polymorphic ventricular tachycardia--part II: the channelopathies. Curr Probl Cardiol 2014; 38:503-48. [PMID: 24262155 DOI: 10.1016/j.cpcardiol.2013.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In this article, we explore the clinical and cellular phenomena of primary electrical diseases of the heart, that is, conditions purely related to ion channel dysfunction and not structural heart disease or reversible acquired causes. This growing classification of conditions, once considered together as "idiopathic ventricular fibrillation," continues to evolve and segregate into diseases that are phenotypically, molecularly, and genetically unique.
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PASTOR AGUSTÍN, COSÍO FRANCISCOG. When and Why Is a Patient with a Brugada Sign in the ECG at Risk? J Cardiovasc Electrophysiol 2014; 25:520-521. [DOI: 10.1111/jce.12388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- AGUSTÍN PASTOR
- Cardiology Service of Hospital Universitario de Getafe and the Clinical Department of Universidad Europea; Madrid Spain
| | - FRANCISCO G. COSÍO
- Cardiology Service of Hospital Universitario de Getafe and the Clinical Department of Universidad Europea; Madrid Spain
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Makarawate P, Chaosuwannakit N, Vannaprasaht S, Tassaneeyakul W, Sawanyawisuth K. Outcomes of symptomatic Brugada syndrome patients with implanted cardioverter defibrillators: A report from an endemic area. J Arrhythm 2014. [DOI: 10.1016/j.joa.2013.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Boyle PM, Park CJ, Arevalo HJ, Vigmond EJ, Trayanova NA. Sodium current reduction unmasks a structure-dependent substrate for arrhythmogenesis in the normal ventricles. PLoS One 2014; 9:e86947. [PMID: 24489810 PMCID: PMC3904970 DOI: 10.1371/journal.pone.0086947] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 12/16/2013] [Indexed: 11/22/2022] Open
Abstract
Background Organ-scale arrhythmogenic consequences of source-sink mismatch caused by impaired excitability remain unknown, hindering the understanding of pathophysiology in disease states like Brugada syndrome and ischemia. Objective We sought to determine whether sodium current (INa) reduction in the structurally normal heart unmasks a regionally heterogeneous substrate for the induction of sustained arrhythmia by premature ventricular contractions (PVCs). Methods We conducted simulations in rabbit ventricular computer models with 930 unique combinations of PVC location (10 sites) and coupling interval (250–400 ms), INa reduction (30 or 40% of normal levels), and post-PVC sinus rhythm (arrested or persistent). Geometric characteristics and source-sink mismatch were quantitatively analyzed by calculating ventricular wall thickness and a newly formulated 3D safety factor (SF), respectively. Results Reducing INa to 30% of its normal level created a substrate for sustained arrhythmia induction by establishing large regions of critical source-sink mismatch (SF<1) for ectopic wavefronts propagating from thin to thick tissue. In the same simulations but with 40% of normal INa, PVCs did not induce reentry because the volume of tissue with SF<1 was >95% smaller. Likewise, when post-PVC sinus activations were persistent instead of arrested, no ectopic excitations initiated sustained reentry because sinus activation breakthroughs engulfed the excitable gap. Conclusion Our new SF formulation can quantify ectopic wavefront propagation robustness in geometrically complex 3D tissue with impaired excitability. This novel methodology was applied to show that INa reduction precipitates source-sink mismatch, creating a potent substrate for sustained arrhythmia induction by PVCs originating near regions of ventricular wall expansion, such as the RV outflow tract.
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Affiliation(s)
- Patrick M. Boyle
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Carolyn J. Park
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Hermenegild J. Arevalo
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | | | - Natalia A. Trayanova
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
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Maury P, Rollin A, Sacher F, Gourraud JB, Raczka F, Pasquié JL, Duparc A, Mondoly P, Cardin C, Delay M, Derval N, Chatel S, Bongard V, Sadron M, Denis A, Davy JM, Hocini M, Jaïs P, Jesel L, Haïssaguerre M, Probst V. Prevalence and prognostic role of various conduction disturbances in patients with the Brugada syndrome. Am J Cardiol 2013; 112:1384-9. [PMID: 24011739 DOI: 10.1016/j.amjcard.2013.06.033] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 06/24/2013] [Accepted: 06/24/2013] [Indexed: 11/26/2022]
Abstract
Prevalence and prognostic value of conduction disturbances in patients with the Brugada syndrome (BrS) remains poorly known. Electrocardiograms (ECGs) from 325 patients with BrS (47 ± 13 years, 258 men) with spontaneous (n = 143) or drug-induced (n = 182) type 1 ECG were retrospectively reviewed. Two hundred twenty-six patients (70%) were asymptomatic, 73 patients (22%) presented with unexplained syncope, and 26 patients (8%) presented with sudden death or implantable cardioverter-defibrillator appropriated therapies at diagnosis or during a mean follow-up of 48 ± 34 months. P-wave duration of ≥120 ms was present in 129 patients (40%), first degree atrioventricular block (AVB) in 113 (35%), right bundle branch block (BBB) in 90 (28%), and fascicular block in 52 (16%). Increased P-wave duration, first degree AVB, and right BBB were more often present in patients after drug challenge than in patients with spontaneous type 1 ST elevation. Left BBB was present in 3 patients. SCN5A mutation carriers had longer P-wave duration and longer PR and HV intervals. In multivariate analysis, first degree AVB was independently associated with sudden death or implantable cardioverter-defibrillator appropriated therapies (odds ratio 2.41, 95% confidence interval 1.01 to 5.73, p = 0.046) together with the presence of syncope and spontaneous type 1 ST elevation. In conclusion, conduction disturbances are frequent and sometimes diffuse in patients with BrS. First degree AVB is independently linked to outcome and may be proposed to be used for individual risk stratification.
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Dogan M, Ertem A, Cimen T, Yeter E. Type-1 Brugada-like ECG pattern induced by adrenal crisis. Herz 2013; 40:304-6. [DOI: 10.1007/s00059-013-3983-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 09/06/2013] [Accepted: 09/07/2013] [Indexed: 10/26/2022]
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Ohkubo K, Watanabe I, Okumura Y, Kofune M, Nagashima K, Mano H, Sonoda K, Nakai T, Kunimoto S, Kasamaki Y, Hirayama A, Sumitomo N, Nakayama T. Supraventricular tachyarrhythmia in patients with Brugada syndrome: A single-center study. J Arrhythm 2013. [DOI: 10.1016/j.joa.2013.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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LETSAS KONSTANTINOSP, KAVVOURAS CHARALAMPOS, KOLLIAS GEORGE, TSIKRIKAS SPYRIDON, KORANTZOPOULOS PANAGIOTIS, EFREMIDIS MICHALIS, SIDERIS ANTONIOS. Drug-Induced Brugada Syndrome by Noncardiac Agents. Pacing Clin Electrophysiol 2013; 36:1570-7. [DOI: 10.1111/pace.12234] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 05/31/2013] [Accepted: 06/03/2013] [Indexed: 11/30/2022]
Affiliation(s)
| | - CHARALAMPOS KAVVOURAS
- Second Department of Cardiology; Evangelismos General Hospital of Athens; Athens Greece
| | - GEORGE KOLLIAS
- Second Department of Cardiology; Evangelismos General Hospital of Athens; Athens Greece
| | - SPYRIDON TSIKRIKAS
- Second Department of Cardiology; Evangelismos General Hospital of Athens; Athens Greece
| | | | - MICHALIS EFREMIDIS
- Second Department of Cardiology; Evangelismos General Hospital of Athens; Athens Greece
| | - ANTONIOS SIDERIS
- Second Department of Cardiology; Evangelismos General Hospital of Athens; Athens Greece
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King JH, Huang CLH, Fraser JA. Determinants of myocardial conduction velocity: implications for arrhythmogenesis. Front Physiol 2013; 4:154. [PMID: 23825462 PMCID: PMC3695374 DOI: 10.3389/fphys.2013.00154] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/10/2013] [Indexed: 12/19/2022] Open
Abstract
Slowed myocardial conduction velocity (θ) is associated with an increased risk of re-entrant excitation, predisposing to cardiac arrhythmia. θ is determined by the ion channel and physical properties of cardiac myocytes and by their interconnections. Thus, θ is closely related to the maximum rate of action potential (AP) depolarization [(dV/dt)max], as determined by the fast Na+ current (INa); the axial resistance (ra) to local circuit current flow between cells; their membrane capacitances (cm); and to the geometrical relationship between successive myocytes within cardiac tissue. These determinants are altered by a wide range of pathophysiological conditions. Firstly, INa is reduced by the impaired Na+ channel function that arises clinically during heart failure, ischemia, tachycardia, and following treatment with class I antiarrhythmic drugs. Such reductions also arise as a consequence of mutations in SCN5A such as those occurring in Lenègre disease, Brugada syndrome (BrS), sick sinus syndrome, and atrial fibrillation (AF). Secondly, ra, may be increased due to gap junction decoupling following ischemia, ventricular hypertrophy, and heart failure, or as a result of mutations in CJA5 found in idiopathic AF and atrial standstill. Finally, either ra or cm could potentially be altered by fibrotic change through the resultant decoupling of myocyte–myocyte connections and coupling of myocytes with fibroblasts. Such changes are observed in myocardial infarction and cardiomyopathy or following mutations in MHC403 and SCN5A resulting in hypertrophic cardiomyopathy (HCM) or Lenègre disease, respectively. This review defines and quantifies the determinants of θ and summarizes experimental evidence that links changes in these determinants with reduced myocardial θ and arrhythmogenesis. It thereby identifies the diverse pathophysiological conditions in which abnormal θ may contribute to arrhythmia.
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Affiliation(s)
- James H King
- Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge Cambridge, UK
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