151
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Outcomes of defibrillator therapy in catecholaminergic polymorphic ventricular tachycardia. Heart Rhythm 2014; 11:58-66. [DOI: 10.1016/j.hrthm.2013.10.027] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Indexed: 11/20/2022]
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152
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153
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Priori SG, Wilde AA, Horie M, Cho Y, Behr ER, Berul C, Blom N, Brugada J, Chiang CE, Huikuri H, Kannankeril P, Krahn A, Leenhardt A, Moss A, Schwartz PJ, Shimizu W, Tomaselli G, Tracy C. HRS/EHRA/APHRS Expert Consensus Statement on the Diagnosis and Management of Patients with Inherited Primary Arrhythmia Syndromes. Heart Rhythm 2013; 10:1932-63. [DOI: 10.1016/j.hrthm.2013.05.014] [Citation(s) in RCA: 1341] [Impact Index Per Article: 121.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Indexed: 12/15/2022]
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154
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Abstract
Ca²⁺ plays a crucial role in connecting membrane excitability with contraction in myocardium. The hallmark features of heart failure are mechanical dysfunction and arrhythmias; defective intracellular Ca²⁺ homeostasis is a central cause of contractile dysfunction and arrhythmias in failing myocardium. Defective Ca²⁺ homeostasis in heart failure can result from pathological alteration in the expression and activity of an increasingly understood collection of Ca²⁺ homeostatic and structural proteins, ion channels, and enzymes. This review focuses on the molecular mechanisms of defective Ca²⁺ cycling in heart failure and considers how fundamental understanding of these pathways may translate into novel and innovative therapies.
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Affiliation(s)
- Min Luo
- Division of Cardiovascular Medicine, Department of Internal Medicine, Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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155
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Singh VP, Rubinstein J, Arvanitis DA, Ren X, Gao X, Haghighi K, Gilbert M, Iyer VR, Kim DH, Cho C, Jones K, Lorenz JN, Armstrong CF, Wang HS, Gyorke S, Kranias EG. Abnormal calcium cycling and cardiac arrhythmias associated with the human Ser96Ala genetic variant of histidine-rich calcium-binding protein. J Am Heart Assoc 2013; 2:e000460. [PMID: 24125847 PMCID: PMC3835262 DOI: 10.1161/jaha.113.000460] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND A human genetic variant (Ser96Ala) in the sarcoplasmic reticulum (SR) histidine-rich Ca(2+)-binding (HRC) protein has been linked to ventricular arrhythmia and sudden death in dilated cardiomyopathy. However, the precise mechanisms affecting SR function and leading to arrhythmias remain elusive. METHODS AND RESULTS We generated transgenic mice with cardiac-specific expression of human Ala96 HRC or Ser96 HRC in the null background to assess function in absence of endogenous protein. Ala96 HRC decreased (25% to 30%) cardiomyocyte contractility and Ca2+ kinetics compared with Ser96 HRC in the absence of any structural or histological abnormalities. Furthermore, the frequency of Ca2+ waves was significantly higher (10-fold), although SR Ca2+ load was reduced (by 27%) in Ala96 HRC cells. The underlying mechanisms involved diminished interaction of Ala96 HRC with triadin, affecting ryanodine receptor (RyR) stability. Indeed, the open probability of RyR, assessed by use of ryanodine binding, was significantly increased. Accordingly, stress conditions (5 Hz plus isoproterenol) induced aftercontractions (65% in Ala96 versus 12% in Ser96) and delayed afterdepolarizations (70% in Ala96 versus 20% in Ser96). The increased SR Ca2+ leak was accompanied by hyperphosphorylation (1.6-fold) of RyR at Ser2814 by calmodulin-dependent protein kinase II. Accordingly, inclusion of the calmodulin-dependent protein kinase II inhibitor KN93 prevented Ser2814 phosphorylation and partially reversed the increases in Ca2+ spark frequency and wave production. Parallel in vivo studies revealed ventricular ectopy on short-term isoproterenol challenge and increased (4-fold) propensity to arrhythmias, including nonsustained ventricular tachycardia, after myocardial infarction in Ala96 HRC mice. CONCLUSIONS These findings suggest that aberrant SR Ca2+ release and increased susceptibility to delayed afterdepolarizations underlie triggered arrhythmic activity in human Ala96 HRC carriers.
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Affiliation(s)
- Vivek P Singh
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH
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156
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Biermann J, Faber TS. [Ventricular tachycardia under stress : Characteristic symptom or prognostic relevance?]. Herzschrittmacherther Elektrophysiol 2013; 24:197-201. [PMID: 24100620 DOI: 10.1007/s00399-013-0293-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 09/16/2013] [Indexed: 10/26/2022]
Abstract
Exercise-induced ventricular tachycardia (EIVT) is typical and quite common in patients with long QT-Syndrome (LQTS) or catecholaminergic polymorphic ventricular tachycardia (CPVT). Although patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) or hypertrophic cardiomyopathy (HCM) experience EIVT infrequently, the occurrence of EIVT is of great prognostic value in these patients. The following overview will introduce these cardiomyopathies and highlight the importance of their EIVT.
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Affiliation(s)
- Jürgen Biermann
- Klinik für Kardiologie und Angiologie I, Universitäts-Herzzentrum Freiburg - Bad Krozingen, Hugstetter Straße 55, 79106, Freiburg i. Br., Deutschland,
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157
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Jabbari J, Jabbari R, Nielsen MW, Holst AG, Nielsen JB, Haunsø S, Tfelt-Hansen J, Svendsen JH, Olesen MS. New Exome Data Question the Pathogenicity of Genetic Variants Previously Associated With Catecholaminergic Polymorphic Ventricular Tachycardia. ACTA ACUST UNITED AC 2013; 6:481-9. [DOI: 10.1161/circgenetics.113.000118] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Background—
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a lethal, rare hereditary disease with an estimated prevalence of 1:10 000. The genetic variants that cause CPVT are usually highly penetrant. To date, about 189 variants in 5 genes (
RYR2, CASQ2, CALM1, TRND
, and
KCNJ2
) have been associated with CPVT pathogenesis.
Methods and Results—
The Exome Sequencing Project database (ESP; n= 6503) was systematically searched for previously published missense and nonsense CPVT–associated variants reported in several comprehensive reviews and in 2 databases: The Human Gene Mutation Database and The Inherited Arrhythmias Database. We used 4 different prediction tools to assess all missense variants previously associated with CPVT and compared the prediction of protein damage between CPVT-associated variants identified in the ESP and those variants not identified in the ESP. We identified 11% of the variants previously associated with CPVT in the ESP population. In the literature, 57% of these variants were reported as novel disease-causing variants absent in the healthy control subjects. These putative CPVT variants were identified in 41 out of 6131 subjects in the ESP population, corresponding to a prevalence of CPVT of up to 1:150. Using an agreement of ≥3, in silico prediction tools showed a significantly higher frequency of damaging variants among the CPVT-associated variants not identified in the ESP database (83%) compared with those variants identified in the ESP (50%;
P
=0.021).
Conclusions—
We identified a substantial overrepresentation of CPVT-associated variants in a large exome database, suggesting that these variants are not necessarily the monogenic cause of CPVT.
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Affiliation(s)
- Javad Jabbari
- From the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); and Department of Clinical Medicine, Faculty of Health Sciences (S.H., J.T.-H., J.H.S.), University of Copenhagen, Copenhagen, Denmark
| | - Reza Jabbari
- From the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); and Department of Clinical Medicine, Faculty of Health Sciences (S.H., J.T.-H., J.H.S.), University of Copenhagen, Copenhagen, Denmark
| | - Morten W. Nielsen
- From the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); and Department of Clinical Medicine, Faculty of Health Sciences (S.H., J.T.-H., J.H.S.), University of Copenhagen, Copenhagen, Denmark
| | - Anders G. Holst
- From the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); and Department of Clinical Medicine, Faculty of Health Sciences (S.H., J.T.-H., J.H.S.), University of Copenhagen, Copenhagen, Denmark
| | - Jonas B. Nielsen
- From the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); and Department of Clinical Medicine, Faculty of Health Sciences (S.H., J.T.-H., J.H.S.), University of Copenhagen, Copenhagen, Denmark
| | - Stig Haunsø
- From the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); and Department of Clinical Medicine, Faculty of Health Sciences (S.H., J.T.-H., J.H.S.), University of Copenhagen, Copenhagen, Denmark
| | - Jacob Tfelt-Hansen
- From the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); and Department of Clinical Medicine, Faculty of Health Sciences (S.H., J.T.-H., J.H.S.), University of Copenhagen, Copenhagen, Denmark
| | - Jesper H. Svendsen
- From the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); and Department of Clinical Medicine, Faculty of Health Sciences (S.H., J.T.-H., J.H.S.), University of Copenhagen, Copenhagen, Denmark
| | - Morten S. Olesen
- From the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital (J.J., R.J., M.W.N., A.G.H., J.B.N., S.H., J.T.-H., J.H.S., M.S.O.); and Department of Clinical Medicine, Faculty of Health Sciences (S.H., J.T.-H., J.H.S.), University of Copenhagen, Copenhagen, Denmark
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158
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Priori SG, Wilde AA, Horie M, Cho Y, Behr ER, Berul C, Blom N, Brugada J, Chiang CE, Huikuri H, Kannankeril P, Krahn A, Leenhardt A, Moss A, Schwartz PJ, Shimizu W, Tomaselli G, Tracy C, Ackerman M, Belhassen B, Estes NAM, Fatkin D, Kalman J, Kaufman E, Kirchhof P, Schulze-Bahr E, Wolpert C, Vohra J, Refaat M, Etheridge SP, Campbell RM, Martin ET, Quek SC. Executive summary: HRS/EHRA/APHRS expert consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes. Europace 2013; 15:1389-406. [PMID: 23994779 DOI: 10.1093/europace/eut272] [Citation(s) in RCA: 408] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Silvia G Priori
- From the Maugeri Foundation IRCCS, Pavia, Italy, Department of Molecular Medicine, University of Pavia, Pavia, Italy, and New York University, New York, New York
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159
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Lee YS, Liu OZ, Hwang HS, Knollmann BC, Sobie EA. Parameter sensitivity analysis of stochastic models provides insights into cardiac calcium sparks. Biophys J 2013; 104:1142-50. [PMID: 23473497 DOI: 10.1016/j.bpj.2012.12.055] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 12/02/2012] [Accepted: 12/31/2012] [Indexed: 01/14/2023] Open
Abstract
We present a parameter sensitivity analysis method that is appropriate for stochastic models, and we demonstrate how this analysis generates experimentally testable predictions about the factors that influence local Ca(2+) release in heart cells. The method involves randomly varying all parameters, running a single simulation with each set of parameters, running simulations with hundreds of model variants, then statistically relating the parameters to the simulation results using regression methods. We tested this method on a stochastic model, containing 18 parameters, of the cardiac Ca(2+) spark. Results show that multivariable linear regression can successfully relate parameters to continuous model outputs such as Ca(2+) spark amplitude and duration, and multivariable logistic regression can provide insight into how parameters affect Ca(2+) spark triggering (a probabilistic process that is all-or-none in a single simulation). Benchmark studies demonstrate that this method is less computationally intensive than standard methods by a factor of 16. Importantly, predictions were tested experimentally by measuring Ca(2+) sparks in mice with knockout of the sarcoplasmic reticulum protein triadin. These mice exhibit multiple changes in Ca(2+) release unit structures, and the regression model both accurately predicts changes in Ca(2+) spark amplitude (30% decrease in model, 29% decrease in experiments) and provides an intuitive and quantitative understanding of how much each alteration contributes to the result. This approach is therefore an effective, efficient, and predictive method for analyzing stochastic mathematical models to gain biological insight.
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Affiliation(s)
- Young-Seon Lee
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, USA
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160
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Abstract
Proper generation and conduction of the cardiac electrical impulse is essential for the continuous coordinated contraction of the heart. Dysregulation of cardiac electrical function may lead to cardiac arrhythmias, which constitute a huge medical and social burden. Identifying the genetic factors underlying cardiac electrical activity serves the double purpose of allowing the early identification of individuals at risk for arrhythmia and discovering new potential therapeutic targets for prevention. The aim of this review is to provide an overview of the genes and genetic loci linked thus far to cardiac electrical function and arrhythmia. These genes and loci have been primarily uncovered through studies on the familial rhythm disorders and through genome-wide association studies on electrocardiographic parameters in large sets of the general population. An overview of all genes and loci with their respective effect is given.
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Affiliation(s)
- Elisabeth M Lodder
- Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Tel.: +31 20 5665962; Fax: +31 20 6976177;
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161
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Current perspectives in genetic cardiovascular disorders: from basic to clinical aspects. Heart Vessels 2013; 29:129-41. [PMID: 23907713 DOI: 10.1007/s00380-013-0391-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 06/27/2013] [Indexed: 12/18/2022]
Abstract
We summarize recent advances in the clinical genetics of hypercholesterolemia, hypertrophic cardiomyopathy (HCM), and lethal arrhythmia, all of which are monogenic cardiovascular diseases being essential to understanding the heart and circulatory pathophysiology. Among the issues of hypercholesterolemia which play a pivotal role in development of vascular damages, familial hypercholesterolemia is the common genetic cardiovascular disease; in addition to identifying the gene mutation coding low-density lipoprotein receptor, lipid kinetics in autosomal recessive hypercholesterolemia as well as in proprotein convertase subtilisin/kexin 9 gene mutation were recently demonstrated. As for HCM, some gene mutations were identified to correlate with clinical manifestations. Additionally, a gene polymorphism of the renin-angiotensin system in development of heart failure was identified as a modifier gene. The lethal arrhythmias such as sudden death syndromes, QT prolongation, and Brugada syndrome were found to exhibit gene mutation coding potassium and/or sodium ion channels. Interestingly, functional analysis of these gene mutations helped to identify the role of each gene mutation in developing these cardiovascular disorders. We suggest considering the genetic mechanisms of cardiovascular diseases associated with hyperlipidemia, myocardial hypertrophy, or lethal arrhythmia in terms of not only clinical diagnosis but also understanding pathophysiology of each disease with therapeutic aspects.
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162
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Executive summary: HRS/EHRA/APHRS expert consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes. Heart Rhythm 2013; 10:e85-108. [PMID: 23916535 DOI: 10.1016/j.hrthm.2013.07.021] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Indexed: 02/07/2023]
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163
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164
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The CPVT-associated RyR2 mutation G230C enhances store overloadinduced Ca2+ release and destabilizes the N-terminal domains. Biochem J 2013; 454:123-31. [DOI: 10.1042/bj20130594] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
CPVT (catecholaminergic polymorphic ventricular tachycardia) is an inherited life-threatening arrhythmogenic disorder. CPVT is caused by DADs (delayed after-depolarizations) that are induced by spontaneous Ca2+ release during SR (sarcoplasmic reticulum) Ca2+ overload, a process also known as SOICR (store-overload-induced Ca2+ release). A number of mutations in the cardiac ryanodine receptor RyR2 are linked to CPVT. Many of these CPVT-associated RyR2 mutations enhance the propensity for SOICR and DADs by sensitizing RyR2 to luminal or luminal/cytosolic Ca2+ activation. Recently, a novel CPVT RyR2 mutation, G230C, was found to increase the cytosolic, but not the luminal, Ca2+ sensitivity of single RyR2 channels in lipid bilayers. This observation led to the suggestion of a SOICR-independent disease mechanism for the G230C mutation. However, the cellular impact of this mutation on SOICR is yet to be determined. To this end, we generated stable inducible HEK (human embryonic kidney)-293 cell lines expressing the RyR2 WT (wild-type) and the G230C mutant. Using single-cell Ca2+ imaging, we found that the G230C mutation markedly enhanced the propensity for SOICR and reduced the SOICR threshold. Furthermore, the G230C mutation increased the sensitivity of single RyR2 channels to both luminal and cytosolic Ca2+ activation and the Ca2+-dependent activation of [3H]ryanodine binding. In addition, the G230C mutation decreased the thermal stability of the N-terminal region (amino acids 1–547) of RyR2. These data suggest that the G230C mutation enhances the propensity for SOICR by sensitizing the channel to luminal and cytosolic Ca2+ activation, and that G230C has an intrinsic structural impact on the N-terminal domains of RyR2.
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165
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Abstract
Many neurologic diseases cause discrete episodic impairment in contrast with progressive deterioration. The symptoms of these episodic disorders exhibit striking variety. Herein we review what is known of the phenotypes, genetics, and pathophysiology of episodic neurologic disorders. Of these, most are genetically complex, with unknown or polygenic inheritance. In contrast, a fascinating panoply of episodic disorders exhibit Mendelian inheritance. We classify episodic Mendelian disorders according to the primary neuroanatomical location affected: skeletal muscle, cardiac muscle, neuromuscular junction, peripheral nerve, or central nervous system (CNS). Most known Mendelian mutations alter genes that encode membrane-bound ion channels. These mutations cause ion channel dysfunction, which ultimately leads to altered membrane excitability as manifested by episodic disease. Other Mendelian disease genes encode proteins essential for ion channel trafficking or stability. These observations have cemented the channelopathy paradigm, in which episodic disorders are conceptualized as disorders of ion channels. However, we expand on this paradigm to propose that dysfunction at the synaptic and neuronal circuit levels may underlie some episodic neurologic entities.
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Affiliation(s)
- Jonathan F Russell
- Department of Neurology, Howard Hughes Medical Institute, School of Medicine, University of California-San Francisco, CA 94158, USA.
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166
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Manno C, Figueroa L, Royer L, Pouvreau S, Lee CS, Volpe P, Nori A, Zhou J, Meissner G, Hamilton SL, Ríos E. Altered Ca2+ concentration, permeability and buffering in the myofibre Ca2+ store of a mouse model of malignant hyperthermia. J Physiol 2013; 591:4439-57. [PMID: 23798496 DOI: 10.1113/jphysiol.2013.259572] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Malignant hyperthermia (MH) is linked to mutations in the type 1 ryanodine receptor, RyR1, the Ca2+ channel of the sarcoplasmic reticulum (SR) of skeletal muscle. The Y522S MH mutation was studied for its complex presentation, which includes structurally and functionally altered cell 'cores'. Imaging cytosolic and intra-SR [Ca2+] in muscle cells of heterozygous YS mice we determined Ca2+ release flux activated by clamp depolarization, permeability (P) of the SR membrane (ratio of flux and [Ca2+] gradient) and SR Ca2+ buffering power (B). In YS cells resting [Ca2+]SR was 45% of the value in normal littermates (WT). P was more than doubled, so that initial flux was normal. Measuring [Ca2+]SR(t) revealed dynamic changes in B(t). The alterations were similar to those caused by cytosolic BAPTA, which promotes release by hampering Ca2+-dependent inactivation (CDI). The [Ca2+] transients showed abnormal 'breaks', decaying phases after an initial rise, traced to a collapse in flux and P. Similar breaks occurred in WT myofibres with calsequestrin reduced by siRNA; calsequestrin content, however, was normal in YS muscle. Thus, the Y522S mutation causes greater openness of the RyR1, lowers resting [Ca2+]SR and alters SR Ca2+ buffering in a way that copies the functional instability observed upon reduction of calsequestrin content. The similarities with the effects of BAPTA suggest that the mutation, occurring near the cytosolic vestibule of the channel, reduces CDI as one of its primary effects. The unstable SR buffering, mimicked by silencing of calsequestrin, may help precipitate the loss of Ca2+ control that defines a fulminant MH event.
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Affiliation(s)
- Carlo Manno
- S. L. Hamilton: ; E. Ríos: Rush University School of Medicine, Department of Molecular Biophysics and Physiology, 1750 West Harrison St., Suite 1279JS, Chicago, IL 60612, USA.
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167
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Sorensen AB, Søndergaard MT, Overgaard MT. Calmodulin in a Heartbeat. FEBS J 2013; 280:5511-32. [DOI: 10.1111/febs.12337] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 04/28/2013] [Accepted: 05/07/2013] [Indexed: 01/16/2023]
Affiliation(s)
- Anders B. Sorensen
- Department of Biotechnology, Chemistry and Environmental Engineering; Aalborg University; Denmark
| | - Mads T. Søndergaard
- Department of Biotechnology, Chemistry and Environmental Engineering; Aalborg University; Denmark
| | - Michael T. Overgaard
- Department of Biotechnology, Chemistry and Environmental Engineering; Aalborg University; Denmark
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168
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Schwartz PJ, Ackerman MJ, George AL, Wilde AAM. Impact of genetics on the clinical management of channelopathies. J Am Coll Cardiol 2013; 62:169-180. [PMID: 23684683 DOI: 10.1016/j.jacc.2013.04.044] [Citation(s) in RCA: 220] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/11/2013] [Accepted: 04/24/2013] [Indexed: 12/29/2022]
Abstract
There are few areas in cardiology in which the impact of genetics and genetic testing on clinical management has been as great as in cardiac channelopathies, arrhythmic disorders of genetic origin related to the ionic control of the cardiac action potential. Among the growing number of diseases identified as channelopathies, 3 are sufficiently prevalent to represent significant clinical and societal problems and to warrant adequate understanding by practicing cardiologists: long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and Brugada syndrome. This review will focus selectively on the impact of genetic discoveries on clinical management of these 3 diseases. For each disorder, we will discuss to what extent genetic knowledge and clinical genetic test results modify the way cardiologists should approach and manage affected patients. We will also address the optimal use of genetic testing, including its potential limitations and the potential medico-legal implications when such testing is not performed. We will highlight how important it is to understand the ways that genotype can affect clinical manifestations, risk stratification, and responses to the therapy. We will also illustrate the close bridge between molecular biology and clinical medicine, and will emphasize that consideration of the genetic basis for these heritable arrhythmia syndromes and the proper use and interpretation of clinical genetic testing should remain the standard of care.
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Affiliation(s)
- Peter J Schwartz
- Department of Molecular Medicine, University of Pavia, Pavia, Italy; Department of Cardiology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; Cardiovascular Genetics Laboratory, Hatter Institute for Cardiovascular Research in Africa, Department of Medicine, University of Cape Town, Cape Town, South Africa; Department of Medicine, University of Stellenbosch, Stellenbosch, South Africa; Chair of Sudden Death, Department of Family and Community Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
| | - Michael J Ackerman
- Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota; Department of Pediatrics, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Alfred L George
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee; Institute for Integrative Genomics, Vanderbilt University, Nashville, Tennessee
| | - Arthur A M Wilde
- Department of Cardiology, Heart Failure Research Centre, Academic Medical Centre, Amsterdam, the Netherlands; Princess Al Jawhara Albrahim Centre of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia
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Ackerman MJ, Marcou CA, Tester DJ. Medicina personalizada: diagnóstico genético de cardiopatías/canalopatías hereditarias. Rev Esp Cardiol 2013. [DOI: 10.1016/j.recesp.2012.12.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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170
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Ackerman MJ, Marcou CA, Tester DJ. Personalized medicine: genetic diagnosis for inherited cardiomyopathies/channelopathies. ACTA ACUST UNITED AC 2013; 66:298-307. [PMID: 24775620 DOI: 10.1016/j.rec.2012.12.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 12/13/2012] [Indexed: 11/30/2022]
Abstract
Major advances in the field of molecular genetics have expanded our ability to identify genetic substrates underlying the pathogenesis of various disorders that follow Mendelian inheritance patterns. Included among these disorders are the potentially lethal and heritable channelopathies and cardiomyopathies for which the underlying genetic basis has been identified and is now better understood. Clinical and genetic heterogeneity are hallmark features of these disorders, with thousands of gene mutations being implicated within these divergent cardiovascular diseases. Genetic testing for several of these heritable channelopathies and cardiomyopathies has matured from discovery to research-based genetic testing to clinically/commercially available diagnostic tests. The purpose of this review is to provide the reader with a basic understanding of human medical genetics and genetic testing in the context of cardiovascular diseases of the heart. We review the state of clinical genetic testing for the more common channelopathies and cardiomyopathies, discuss some of the pertinent issues that arise from genetic testing, and discuss the future of personalized medicine in cardiovascular disease.
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Affiliation(s)
- Michael J Ackerman
- Departments of Medicine (Division of Cardiovacular Diseases), Pediatrics (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota, United States.
| | - Cherisse A Marcou
- Departments of Medicine (Division of Cardiovacular Diseases), Pediatrics (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota, United States
| | - David J Tester
- Departments of Medicine (Division of Cardiovacular Diseases), Pediatrics (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota, United States
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171
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172
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Chopra N, Knollmann BC. Triadin regulates cardiac muscle couplon structure and microdomain Ca(2+) signalling: a path towards ventricular arrhythmias. Cardiovasc Res 2013; 98:187-91. [PMID: 23396608 DOI: 10.1093/cvr/cvt023] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Since the discovery of triadin >20 years ago as one of the major proteins located in the junctional sarcoplasmic reticulum, the field has come a long way in understanding the pivotal role of triadin in orchestrating sarcoplasmic reticulum Ca(2+)-release and hence excitation-contraction (EC) coupling. Building on the information gathered from earlier lipid bilayer and myocyte overexpression studies, the gene-targeted ablation of Trdn demonstrated triadin's indispensable role for maintaining the structural integrity of the couplon. More recently, the discovery of inherited and acquired diseases displaying altered expression and function of triadin has further emphasized the role of triadin in health and disease. Novel therapeutic approaches could be aimed at correcting the loss of triadin in diseased hearts, and thereby correcting the sub-cellular EC coupling defect. This review summarizes current concepts of the impact of triadin on cardiac EC coupling with a focus towards triadin's role for ventricular arrhythmia.
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Affiliation(s)
- Nagesh Chopra
- Division of Cardiovascular Medicine, Arrhythmia Unit, Brigham and Women's Hospital, Boston, MA, USA
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173
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Gillespie D, Fill M. Pernicious attrition and inter-RyR2 CICR current control in cardiac muscle. J Mol Cell Cardiol 2013; 58:53-8. [PMID: 23369697 DOI: 10.1016/j.yjmcc.2013.01.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 01/07/2013] [Accepted: 01/20/2013] [Indexed: 10/27/2022]
Abstract
In cardiac muscle cells, ryanodine receptor (RyR) mediated Ca(2+) release from the sarcoplasmic reticulum (SR) drives the contractile apparatus. Spontaneous bouts of inter-RyR Ca(2+) induced Ca(2+) release (CICR) generate an elemental unit of SR Ca(2+) release called a spark. Sparks are localized events that terminate soon after they begin. The local control of sparks is not clearly understood. In this article, we review the potential regulatory role that the changing single RyR Ca(2+) current may play. Moreover, we aggregate RyR data into a working scheme of inter-RyR CICR current control of sparks and a potential inter-RyR CICR termination mechanism that we call pernicious attrition.
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Affiliation(s)
- Dirk Gillespie
- Rush University Medical Center, Department of Molecular Biophysics & Physiology, Section of Cellular Signaling, 1750 West Harrison Street, Chicago, IL 60612, USA
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174
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Faggioni M, Hwang HS, van der Werf C, Nederend I, Kannankeril PJ, Wilde AAM, Knollmann BC. Accelerated sinus rhythm prevents catecholaminergic polymorphic ventricular tachycardia in mice and in patients. Circ Res 2013; 112:689-97. [PMID: 23295832 DOI: 10.1161/circresaha.111.300076] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Catecholaminergic polymorphic ventricular tachycardia (CPVT) is caused by mutations in cardiac ryanodine receptor (RyR2) or calsequestrin (Casq2) genes. Sinoatrial node dysfunction associated with CPVT may increase the risk for ventricular arrhythmia (VA). OBJECTIVE To test the hypothesis that CPVT is suppressed by supraventricular overdrive stimulation. METHODS AND RESULTS Using CPVT mouse models (Casq2(-/-) and RyR2(R4496C/+) mice), the effect of increasing sinus heart rate was tested by pretreatment with atropine and by atrial overdrive pacing. Increasing intrinsic sinus rate with atropine before catecholamine challenge suppressed ventricular tachycardia in 86% of Casq2(-/-) mice (6/7) and significantly reduced the VA score (atropine: 0.6±0.2 versus vehicle: 1.7±0.3; P<0.05). Atrial overdrive pacing completely prevented VA in 16 of 19 (84%) Casq2(-/-) and in 7 of 8 (88%) RyR2(R4496C/+) mice and significantly reduced ventricular premature beats in both CPVT models (P<0.05). Rapid pacing also prevented spontaneous calcium waves and triggered beats in isolated CPVT myocytes. In humans, heart rate dependence of CPVT was evaluated by screening a CPVT patient registry for antiarrhythmic drug-naïve individuals that reached >85% of their maximum-predicted heart rate during exercise testing. All 18 CPVT patients who fulfilled the inclusion criteria exhibited VA before reaching 87% of maximum heart rate. In 6 CPVT patients (33%), VA were paradoxically suppressed as sinus heart rates increased further with continued exercise. CONCLUSIONS Accelerated supraventricular rates suppress VAs in 2 CPVT mouse models and in a subset of CPVT patients. Hypothetically, atrial overdrive pacing may be a therapy for preventing exercise-induced ventricular tachycardia in treatment-refractory CPVT patients.
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Affiliation(s)
- Michela Faggioni
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-0575, USA
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175
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Abstract
The abrupt cessation of effective cardiac function due to an aberrant heart rhythm can cause sudden and unexpected death at any age, a syndrome called sudden cardiac death (SCD). Annually, more than 300,000 cases of SCD occur in the United States alone, making this a major public health concern. Our current understanding of the mechanisms responsible for SCD has emerged from decades of basic science investigation into the normal electrophysiology of the heart, the molecular physiology of cardiac ion channels, fundamental cellular and tissue events associated with cardiac arrhythmias, and the molecular genetics of monogenic disorders of heart rhythm. This knowledge has helped shape the current diagnosis and treatment of inherited arrhythmia susceptibility syndromes associated with SCD and has provided a pathophysiological framework for understanding more complex conditions predisposing to this tragic event. This Review presents an overview of the molecular basis of SCD, with a focus on monogenic arrhythmia syndromes.
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Affiliation(s)
- Alfred L George
- Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA.
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176
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Kawamura M, Ohno S, Naiki N, Nagaoka I, Dochi K, Wang Q, Hasegawa K, Kimura H, Miyamoto A, Mizusawa Y, Itoh H, Makiyama T, Sumitomo N, Ushinohama H, Oyama K, Murakoshi N, Aonuma K, Horigome H, Honda T, Yoshinaga M, Ito M, Horie M. Genetic Background of Catecholaminergic Polymorphic Ventricular Tachycardia in Japan. Circ J 2013; 77:1705-13. [DOI: 10.1253/circj.cj-12-1460] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mihoko Kawamura
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Seiko Ohno
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Nobu Naiki
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Iori Nagaoka
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Kenichi Dochi
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Qi Wang
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Kanae Hasegawa
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Hiromi Kimura
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Akashi Miyamoto
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Yuka Mizusawa
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Hideki Itoh
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Takeru Makiyama
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine
| | - Naokata Sumitomo
- Department of Pediatrics and Child Health, Nihon University School of Medicine
| | - Hiroya Ushinohama
- Department of Pediatric Cardiology, Fukuoka Children’s Hospital and Medical Center for Infectious Disease
| | - Kotaro Oyama
- Department of Pediatric Cardiology, Iwate Medical University Memorial Heart Center
| | - Nobuyuki Murakoshi
- Cardiovascular Division, Graduate School of Comprehensive Human Sciences, University of Tsukuba
| | - Kazutaka Aonuma
- Cardiovascular Division, Graduate School of Comprehensive Human Sciences, University of Tsukuba
| | | | - Takafumi Honda
- Department of Pediatrics, Tokyo Women’s Medical University Yachiyo Medical Center
| | - Masao Yoshinaga
- Department of Pediatrics, National Hospital Organization Kagoshima Medical Center
| | - Makoto Ito
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
| | - Minoru Horie
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
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177
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Watanabe H, van der Werf C, Roses-Noguer F, Adler A, Sumitomo N, Veltmann C, Rosso R, Bhuiyan ZA, Bikker H, Kannankeril PJ, Horie M, Minamino T, Viskin S, Knollmann BC, Till J, Wilde AAM. Effects of flecainide on exercise-induced ventricular arrhythmias and recurrences in genotype-negative patients with catecholaminergic polymorphic ventricular tachycardia. Heart Rhythm 2012; 10:542-7. [PMID: 23286974 DOI: 10.1016/j.hrthm.2012.12.035] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Indexed: 02/08/2023]
Abstract
BACKGROUND Conventional therapy with beta-blockers is incompletely effective in preventing arrhythmic events in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT). We have previously discovered that flecainide in addition to conventional drug therapy prevents ventricular arrhythmias in patients with genotype-positive CPVT. OBJECTIVE To study the efficacy of flecainide in patients with genotype-negative CPVT. METHODS We studied the efficacy of flecainide for reducing ventricular arrhythmias during exercise testing and preventing arrhythmia events during long-term follow-up. RESULTS Twelve patients with genotype-negative CPVT were treated with flecainide. Conventional therapy failed to control ventricular arrhythmias in all patients. Flecainide was initiated because of significant ventricular arrhythmias (n = 8), syncope (n = 3), or cardiac arrest (n = 1). At the baseline exercise test before flecainide, 6 patients had ventricular tachycardia and 5 patients had bigeminal or frequent ventricular premature beats. Flecainide reduced ventricular arrhythmias at the exercise test in 8 patients compared to conventional therapy, similar to that in patients with genotype-positive CPVT in our previous report. Notably, flecainide completely prevented ventricular arrhythmias in 7 patients. Flecainide was continued in all patients except for one who had ventricular tachycardia at the exercise test on flecainide. During a follow-up of 48±94 months, arrhythmia events (sudden cardiac death and aborted cardiac arrest) associated with noncompliance occurred in 2 patients. Flecainide was not discontinued owing to side effects in any of the patients. CONCLUSIONS Flecainide was effective in patients with genotype-negative CPVT, suggesting that spontaneous Ca(2+) release from ryanodine channels plays a role in arrhythmia susceptibility, similar to that in patients with genotype-positive CPVT.
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Affiliation(s)
- Hiroshi Watanabe
- Division of Cardiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Wilders R. Cardiac ion channelopathies and the sudden infant death syndrome. ISRN CARDIOLOGY 2012; 2012:846171. [PMID: 23304551 PMCID: PMC3529486 DOI: 10.5402/2012/846171] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 10/23/2012] [Indexed: 12/13/2022]
Abstract
The sudden infant death syndrome (SIDS) causes the sudden death of an apparently healthy infant, which remains unexplained despite a thorough investigation, including the performance of a complete autopsy. The triple risk model for the pathogenesis of SIDS points to the coincidence of a vulnerable infant, a critical developmental period, and an exogenous stressor. Primary electrical diseases of the heart, which may cause lethal arrhythmias as a result of dysfunctioning cardiac ion channels (“cardiac ion channelopathies”) and are not detectable during a standard postmortem examination, may create the vulnerable infant and thus contribute to SIDS. Evidence comes from clinical correlations between the long QT syndrome and SIDS as well as genetic analyses in cohorts of SIDS victims (“molecular autopsy”), which have revealed a large number of mutations in ion channel-related genes linked to inheritable arrhythmogenic syndromes, in particular the long QT syndrome, the short QT syndrome, the Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia. Combining data from population-based cohort studies, it can be concluded that at least one out of five SIDS victims carries a mutation in a cardiac ion channel-related gene and that the majority of these mutations are of a known malignant phenotype.
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Affiliation(s)
- Ronald Wilders
- Department of Anatomy, Embryology and Physiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
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179
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Dulhunty AF, Beard NA, Hanna AD. Regulation and dysregulation of cardiac ryanodine receptor (RyR2) open probability during diastole in health and disease. ACTA ACUST UNITED AC 2012; 140:87-92. [PMID: 22851673 PMCID: PMC3409097 DOI: 10.1085/jgp.201210862] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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180
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Store-dependent deactivation: cooling the chain-reaction of myocardial calcium signaling. J Mol Cell Cardiol 2012; 58:77-83. [PMID: 23108187 DOI: 10.1016/j.yjmcc.2012.10.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/11/2012] [Accepted: 10/21/2012] [Indexed: 01/08/2023]
Abstract
In heart cells, Ca(2+) released from the internal storage unit, the sarcoplasmic reticulum (SR) through ryanodine receptor (RyR2) channels is the predominant determinant of cardiac contractility. Evidence obtained in recent years suggests that SR Ca(2+) release is tightly regulated not only by cytosolic Ca(2+) but also by intra-store Ca(2+) concentration. Specifically, Ca(2+)-induced Ca(2+) release (CICR) that relies on auto-catalytic action of Ca(2+) at the cytosolic side of RyR2s is precisely balanced and counteracted by RyR2 deactivation dependent on a reciprocal decrease of Ca(2+) at the luminal side of RyR2s. Dysregulation of this inherently unstable Ca(2+) signaling is considered to be an underlying cause of triggered arrhythmias, and is associated with genetic and acquired forms of sudden cardiac death. In this article, we present an overview of recent advances in our understanding of the regulatory role luminal Ca(2+) plays in Ca(2+) handling, with a particular emphasis on the role of Ca(2+)release refractoriness in aberrant Ca(2+) release.
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181
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Leenhardt A, Denjoy I, Guicheney P. Catecholaminergic polymorphic ventricular tachycardia. Circ Arrhythm Electrophysiol 2012; 5:1044-52. [PMID: 23022705 DOI: 10.1161/circep.111.962027] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Antoine Leenhardt
- AP-HP, Hôpital Bichat, Service de Cardiologie et Centre de Référence des Maladies Cardiaques Héréditaires, Paris, France.
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182
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Frommeyer G, Pott C, Schulze-Bahr E, Eckardt L. [Catecholaminergic polymorphic ventricular tachycardia]. Herzschrittmacherther Elektrophysiol 2012; 23:231-236. [PMID: 22987135 DOI: 10.1007/s00399-012-0224-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 07/20/2012] [Indexed: 06/01/2023]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (PCVT) is a rare, congenital ventricular tachyarrhythmia which occurs in the setting of adrenergic activation. It potentially leads to syncope and/or sudden cardiac death (SCD). PCVT represents one of the most dangerous congenital ion channel diseases. Mutations of the ryanodine receptor gene (RYR2), the calsequestrin gene (CASQ2), and the triadin gene (TRDN) have been identified as an underlying correlate. β-Blockers are employed as therapy and are sometimes combined with class IC antiarrhythmic drugs, or calcium antagonists of the verapamil type. ICD implantation is recommended in case of persisting syncope in the presence of β-blocker therapy or survived SCD. Left thoracic sympathectomy represents a subsidiary interventional therapy for individual cases. In addition, modifications of the patient's lifestyle including avoidance of physical stress and heart rates> 120/min are recommended.
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Affiliation(s)
- G Frommeyer
- Abteilung für Rhythmologie Department für Kardiologie und Angiologie, Universitätsklinikum Münster, Albert-Schweitzer Campus 1, 48149, Münster, Germany.
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183
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Newbury DF, Mari F, Sadighi Akha E, Macdermot KD, Canitano R, Monaco AP, Taylor JC, Renieri A, Fisher SE, Knight SJL. Dual copy number variants involving 16p11 and 6q22 in a case of childhood apraxia of speech and pervasive developmental disorder. Eur J Hum Genet 2012; 21:361-5. [PMID: 22909776 PMCID: PMC3598310 DOI: 10.1038/ejhg.2012.166] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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184
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Kochhäuser S, Schulze-Bahr E, Kirchhefer U. Arrhythmia-associated cardiac Ca2+ cycling proteins and gene mutations. Wien Med Wochenschr 2012; 162:292-6. [DOI: 10.1007/s10354-012-0114-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 04/17/2012] [Indexed: 11/30/2022]
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