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Younis A, Bos JM, Zareba W, Aktas MK, Wilde AAM, Tabaja C, Bodurian C, Tobert KE, McNitt S, Polonsky B, Shimizu W, Ackerman MJ, Goldenberg I. Association Between Syncope Trigger Type and Risk of Subsequent Life-Threatening Events in Patients With Long QT Syndrome. JAMA Cardiol 2023; 8:775-783. [PMID: 37436769 PMCID: PMC10339217 DOI: 10.1001/jamacardio.2023.1951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 05/13/2023] [Indexed: 07/13/2023]
Abstract
Importance Syncope is the most powerful predictor for subsequent life-threatening events (LTEs) in patients with congenital long QT syndrome (LQTS). Whether distinct syncope triggers are associated with differential subsequent risk of LTEs is unknown. Objective To evaluate the association between adrenergic (AD)- and nonadrenergic (non-AD)-triggered syncopal events and the risk of subsequent LTEs in patients with LQT types 1 to 3 (LQT1-3). Design, Setting, and Participants This retrospective cohort study included data from 5 international LQTS registries (Rochester, New York; the Mayo Clinic, Rochester, Minnesota; Israel, the Netherlands, and Japan). The study population comprised 2938 patients with genetically confirmed LQT1, LQT2, or LQT3 stemming from a single LQTS-causative variant. Patients were enrolled from July 1979 to July 2021. Exposures Syncope by AD and non-AD triggers. Main Outcomes and Measures The primary end point was the first occurrence of an LTE. Multivariate Cox regression was used to determine the association of AD- or non-AD-triggered syncope on the risk of subsequent LTE by genotype. Separate analysis was performed in patients with β-blockers. Results A total of 2938 patients were included (mean [SD] age at enrollment, 29 [7] years; 1645 [56%] female). In 1331 patients with LQT1, a first syncope occurred in 365 (27%) and was induced mostly with AD triggers (243 [67%]). Syncope preceded 43 subsequent LTEs (68%). Syncopal episodes associated with AD triggers were associated with the highest risk of subsequent LTE (hazard ratio [HR], 7.61; 95% CI, 4.18-14.20; P < .001), whereas the risk associated with syncopal events due to non-AD triggers was statistically nonsignificant (HR, 1.50; 95% CI, 0.21-4.77; P = .97). In 1106 patients with LQT2, a first syncope occurred in 283 (26%) and was associated with AD and non-AD triggers in 106 (37%) and 177 (63%), respectively. Syncope preceded 55 LTEs (56%). Both AD- and non-AD-triggered syncope were associated with a greater than 3-fold increased risk of subsequent LTE (HR, 3.07; 95% CI, 1.66-5.67; P ≤ .001 and HR, 3.45, 95% CI, 1.96-6.06; P ≤ .001, respectively). In contrast, in 501 patients with LQT3, LTE was preceded by a syncopal episode in 7 (12%). In patients with LQT1 and LQT2, treatment with β-blockers following a syncopal event was associated with a significant reduction in the risk of subsequent LTEs. The rate of breakthrough events during treatment with β-blockers was significantly higher among those treated with selective agents vs nonselective agents. Conclusion and Relevance In this study, trigger-specific syncope in LQTS patients was associated with differential risk of subsequent LTE and response to β-blocker therapy.
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Affiliation(s)
- Arwa Younis
- Cardiac Electrophysiology Section, Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio
- Clinical Cardiovascular Research Center, University of Rochester Medical Center, Rochester, New York
| | - J. Martijn Bos
- Divisions of Heart Rhythm Services and Pediatric Cardiology, Departments of Cardiovascular Medicine, Pediatric and Adolescent Medicine, and Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Genetic Heart Rhythm Clinic and Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Wojciech Zareba
- Clinical Cardiovascular Research Center, University of Rochester Medical Center, Rochester, New York
| | - Mehmet K. Aktas
- Clinical Cardiovascular Research Center, University of Rochester Medical Center, Rochester, New York
| | - Arthur A. M. Wilde
- Heart Center, Amsterdam Cardiovascular Sciences, Department of Clinical and Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart, Amsterdam, the Netherlands
| | - Chadi Tabaja
- Cardiac Electrophysiology Section, Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio
| | - Christopher Bodurian
- Clinical Cardiovascular Research Center, University of Rochester Medical Center, Rochester, New York
| | - Kathryn E. Tobert
- Divisions of Heart Rhythm Services and Pediatric Cardiology, Departments of Cardiovascular Medicine, Pediatric and Adolescent Medicine, and Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Genetic Heart Rhythm Clinic and Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Scott McNitt
- Clinical Cardiovascular Research Center, University of Rochester Medical Center, Rochester, New York
| | - Bronislava Polonsky
- Clinical Cardiovascular Research Center, University of Rochester Medical Center, Rochester, New York
| | - Wataru Shimizu
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Michael J. Ackerman
- Divisions of Heart Rhythm Services and Pediatric Cardiology, Departments of Cardiovascular Medicine, Pediatric and Adolescent Medicine, and Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Genetic Heart Rhythm Clinic and Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Ilan Goldenberg
- Clinical Cardiovascular Research Center, University of Rochester Medical Center, Rochester, New York
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Pinsky AM, Gao X, Bains S, Kim CJ, Louradour J, Odening KE, Tester DJ, Giudicessi JR, Ackerman MJ. Injectable Contraceptive, Depo-Provera, Produces Erratic Beating Patterns in Patient-Specific Induced Pluripotent Stem Cell-derived Cardiomyocytes with Type 2 Long QT Syndrome. Heart Rhythm 2023; 20:910-917. [PMID: 36889623 DOI: 10.1016/j.hrthm.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 02/22/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023]
Abstract
BACKGROUND Long QT syndrome type 2 (LQT2) is caused by pathogenic variants in KCNH2. LQT2 may manifest as QT prolongation on an ECG and present with arrhythmic syncope/seizures, sudden cardiac arrest/death. Oral progestin-based contraceptives may increase the risk of LQT2-triggered cardiac events in women. We previously reported on a LQT2 woman with recurrent cardiac events temporally related and attributed to the progestin-based contraceptive, medroxyprogesterone acetate ("Depo-Provera", Depo). OBJECTIVE To evaluate the arrhythmic-risk of Depo in a patient-specific induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) model of LQT2. METHODS An iPSC-CM line was generated from a 40-year-old female with p.G1006Afs*49-KCNH2. A CRISPR/Cas9 gene-edited/variant-corrected, isogenic control (IC) iPSC-CM line was generated. FluoVolt was used to measure the action potential duration (APD) following treatment with 10 μM Depo. Erratic beating patterns characterized as alternating spike amplitudes, alternans, or early after depolarization-like phenomena were assessed using multi-electrode array (MEA) following 10 μM Depo, 1 μM isoproterenol (ISO), or combined Depo + ISO treatment. RESULTS Depo treatment shortened the APD-90 of the G1006Afs*49 iPSC-CMs from 394±10 ms to 303±10 ms (p<0.0001). Combined Depo and ISO treatment increased the percent of electrodes displaying erratic beating in G1006Afs*49 iPSC-CMs [baseline 18±5% vs. Depo + ISO 54±5% (p<0.0001)] but not in IC iPSC-CMs [baseline 0±0% vs. Depo + ISO 10±3% (p=0.9659)]. CONCLUSION This cell study provides a potential mechanism for the patient's clinically documented Depo-associated episodes of recurrent ventricular fibrillation. This in-vitro data should prompt a large-scale clinical assessment of Depo's potential pro-arrhythmic effect in women with LQT2.
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Affiliation(s)
- Alexa M Pinsky
- Departments of Cardiovascular Medicine (Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic), Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN
| | - Xiaozhi Gao
- Departments of Cardiovascular Medicine (Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic), Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN
| | - Sahej Bains
- Departments of Cardiovascular Medicine (Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic), Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN
| | - Cs John Kim
- Departments of Cardiovascular Medicine (Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic), Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN
| | - Julien Louradour
- Translational Cardiology, Department of Cardiology and Department of Physiology, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Katja E Odening
- Translational Cardiology, Department of Cardiology and Department of Physiology, University Hospital Bern, University of Bern, Bern, Switzerland
| | - David J Tester
- Departments of Cardiovascular Medicine (Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic), Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN
| | - John R Giudicessi
- Departments of Cardiovascular Medicine (Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic), Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN
| | - Michael J Ackerman
- Departments of Cardiovascular Medicine (Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic), Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN.
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Champéroux P, Fares R, Bastogne T, Richard S, Le Guennec JY, Thireau J. Contribution of hemodynamic side effects and associated autonomic reflexes to ventricular arrhythmias triggering by torsadogenic hERG blocking drugs. Br J Pharmacol 2022; 179:4549-4562. [PMID: 35751378 PMCID: PMC9543494 DOI: 10.1111/bph.15905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 05/16/2022] [Accepted: 06/01/2022] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSES Several hERG blocking drugs known for their propensity to trigger Torsades de Pointes (TdP) were reported to induce a sympatho-vagal coactivation and to enhance High Frequency heart rate (HFHR) and QT oscillations (HFQT) from telemetric data. The present work aims to characterise the underlying mechanism(s) leading to these autonomic changes. EXPERIMENTAL APPROACH Effects of 15 torsadogenic hERG blocking drugs (astemizole, chlorpromazine, cisapride, droperidol, ibutilide, dofetilide, haloperidol, moxifloxacin, pimozide, quinidine, risperidone, sotalol, sertindole, terfenadine, thioridazine) were assessed by telemetry in beagle dogs. Hemodynamic effects on diastolic and systolic arterial pressure were analysed from the first doses causing QTc prolongation and/or HFQT oscillations enhancement. Autonomic control changes were analysed with the High Frequency Autonomic Modulation (HFAM) model. KEY RESULTS Except moxifloxacin and quinidine, all torsadogenic hERG blockers induced parasympathetic activation or sympatho-vagal coactivation combined with enhancement of HFQT oscillations. These autonomic effects result from reflex compensatory mechanisms in response to mild hemodynamic side effects. These hemodynamic mechanisms were characterised by transient HR acceleration during HF oscillations. A phenomenon of concealed QT prolongation was unmasked for several torsadogenic hERG blockers under β-adrenoceptors blockade by atenolol. Resulting enhancement of HFQT oscillations was shown to contribute directly to triggering of dofetilide induced ventricular arrhythmias. CONCLUSIONS AND IMPLICATIONS This work supports for the first time a contribution of hemodynamic side properties to ventricular arrhythmias triggering by torsadogenic hERG blocking drugs. These hemodynamic side effects may constitute a second component of their arrhythmic profile acting as a trigger alongside their intrinsic arrhythmogenic electrophysiological properties.
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Affiliation(s)
| | - Raafat Fares
- ERBC France, Chemin de Montifault, Baugy, France
| | - Thierry Bastogne
- CRAN CNRS UMR 7039, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | | | - Jean-Yves Le Guennec
- Laboratoire PHYMEDEXP, Université de Montpellier, INSERM, CNRS, Montpellier cedex, France
| | - Jérôme Thireau
- Laboratoire PHYMEDEXP, Université de Montpellier, INSERM, CNRS, Montpellier cedex, France
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Koponen M, Marjamaa A, Väänänen H, Tuiskula AM, Kontula K, Swan H, Viitasalo M. Effects of beta-blockers on ventricular repolarization documented by 24-h electrocardiography in long-QT syndrome type 2. Heart Rhythm 2022; 19:1491-1498. [PMID: 35525424 DOI: 10.1016/j.hrthm.2022.04.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/11/2022] [Accepted: 04/27/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND Long QT syndrome (LQTS) is an inherited arrhythmia disorder characterized by ventricular repolarization abnormalities and a risk of sudden cardiac death. The electrophysiological components generating the high risk of arrhythmias in LQTS are prolonged repolarization, increased dispersion of repolarization, and early afterdepolarizations, which are clinically estimated as QT interval, T-wave peak to end (TPE) interval, and T2/T1-wave amplitude ratio, respectively. In experimental LQTS type 2 (LQT2) models, beta-blockers decrease dispersion of repolarization and prevent early afterdepolarizations. In clinical studies among LQT2 patients beta-blockers are more effective against exercise-induced than arousal-induced cardiac events. OBJECTIVES AND METHODS The aim of the study was to investigate the effects of beta-blocker therapy on QT and TPE intervals, and maximal T2/T1-wave amplitude ratios recorded by 24-h electrocardiograms (ECG) among 25 LQT2 patients. RESULTS Beta-blocker therapy decreased the maximal T2/T1-wave amplitude ratio from 2.9±1.1 to 1.8±0.7 (p<0.001), but did not change pause-induced T2/T1-wave amplitude ratio. Under medication abrupt maximal TPE intervals were shorter at heart rates of 75 beats/min or over, and maximal QT intervals were shorter at a heart rate of 100 beats/min. CONCLUSIONS Beta-blockers stabilize ventricular repolarization in LQT2 by reducing electrocardiographic early afterdepolarizations, and by reducing abrupt prolongation of electrocardiographic dispersion of repolarization and ventricular repolarization duration at elevated heart rates. The effect of beta-blockers on pause-induced electrocardiographic early afterdepolarizations is weak. The findings provide electrocardiographic explanation for the protective effects of beta-blockers against exercise-induced cardiac events in LQT2.
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Affiliation(s)
- Mikael Koponen
- Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland.
| | - Annukka Marjamaa
- Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
| | - Heikki Väänänen
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | - Annukka M Tuiskula
- Department of Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland; HUS Diagnostic Center, Laboratory of Genetics, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Kimmo Kontula
- Department of Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Heikki Swan
- Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
| | - Matti Viitasalo
- Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
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5
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Chan CH, Hu YF, Chen PF, Wu IC, Chen SA. Exercise Test for Patients with Long QT Syndrome. ACTA CARDIOLOGICA SINICA 2022; 38:124-133. [PMID: 35273433 PMCID: PMC8888329 DOI: 10.6515/acs.202203_38(2).20211101a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 11/01/2021] [Indexed: 01/24/2023]
Abstract
Congenital long QT syndrome (LQTS) causes life-threatening cardiac arrhythmias and is the leading cause of sudden cardiac death in young people. Measurements of QT prolongation during exercise or postural change have been recommended to assist in the diagnosis of LQTS, particularly in those with hidden phenotypes. However, most evidence has come from single-center studies without external validation in an independent cohort. Inter-study heterogeneity leads to significant difficulties in interpreting and applying consistent diagnostic criteria for LQTS. A comprehensive systematic review is critically needed to summarize the evidence and validate the diagnostic performance of QT intervals during exercise or postural change across a variety of studies. In this study, we review cross-sectional and cohort studies evaluating the efficacy and feasibility of exercise tests or postural changes in diagnosing LQTS, and propose possible problems resulting from exercise tests.
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Affiliation(s)
- Cheng-Han Chan
- Department of Medicine, Taipei Veterans General Hospital
| | - Yu-Feng Hu
- Faculty of Medicine, National Yang-Ming University;
,
Heart Rhythm Center, Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital;
,
Institute of Biomedical Sciences, Academia Sinica, Taipei
| | - Pei-Fen Chen
- Institute of Population Health Sciences, National Health Research Institutes, Miaoli
| | - I-Chien Wu
- Institute of Population Health Sciences, National Health Research Institutes, Miaoli
| | - Shih-Ann Chen
- Faculty of Medicine, National Yang-Ming University;
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Heart Rhythm Center, Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital;
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Cardiovascular Center, Taichung Veterans General Hospital, Taichung, Taiwan
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Isogenic Sets of hiPSC-CMs Harboring Distinct KCNH2 Mutations Differ Functionally and in Susceptibility to Drug-Induced Arrhythmias. Stem Cell Reports 2021; 15:1127-1139. [PMID: 33176122 PMCID: PMC7664051 DOI: 10.1016/j.stemcr.2020.10.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/26/2022] Open
Abstract
Mutations in KCNH2 can lead to long QT syndrome type 2. Variable disease manifestation observed with this channelopathy is associated with the location and type of mutation within the protein, complicating efforts to predict patient risk. Here, we demonstrated phenotypic differences in cardiomyocytes derived from isogenic human induced pluripotent stem cells (hiPSC-CMs) genetically edited to harbor mutations either within the pore or tail region of the ion channel. Electrophysiological analysis confirmed that the mutations prolonged repolarization of the hiPSC-CMs, with differences between the mutations evident in monolayer cultures. Blocking the hERG channel revealed that the pore-loop mutation conferred greater susceptibility to arrhythmic events. These findings showed that subtle phenotypic differences related to KCNH2 mutations could be captured by hiPSC-CMs under genetically matched conditions. Moreover, the results support hiPSC-CMs as strong candidates for evaluating the underlying severity of individual KCNH2 mutations in humans, which could facilitate patient risk stratification. Mutation-specific differences detected in hiPSC-CMs with same genetic background APD and FPD in the hERG pore variant hiPSC-CMs more prolonged than the tail variant The pore variant was also more susceptible to drug-induced arrhythmic events Potential strategy to determine KCNH2 mutation-specific arrhythmic risk
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Bileišienė N, Barysienė J, Mikštienė V, Preikšaitienė E, Marinskis G, Keževičiūtė M, Utkus A, Aidietis A. Aborted Cardiac Arrest in LQT2 Related to Novel KCNH2 ( hERG) Variant Identified in One Lithuanian Family. ACTA ACUST UNITED AC 2021; 57:medicina57070721. [PMID: 34357002 PMCID: PMC8305506 DOI: 10.3390/medicina57070721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 11/16/2022]
Abstract
Congenital long QT syndrome (LQTS) is a hereditary ion channelopathy associated with ventricular arrhythmia and sudden cardiac death starting from young age due to prolonged cardiac repolarization, which is represented by QT interval changes in electrocardiogram (ECG). Mutations in human ether-à-go-go related gene (KCNH2 (7q36.1), formerly named hERG) are responsible for Long QT syndrome type 2 (LQT2). LQT2 is the second most common type of LQTS. A resuscitated 31-year-old male with the diagnosis of LQT2 and his family are described. Sequencing analysis of their genomic DNA was performed. Amino acid alteration p.(Ser631Pro) in KCNH2 gene was found. This variant had not been previously described in literature, and it was found in three nuclear family members with different clinical course of the disease. Better understanding of genetic alterations and genotype-phenotype correlations aids in risk stratification and more effective management of these patients, especially when employing a trigger-specific approach to risk-assessment and individually tailored therapy.
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Affiliation(s)
- Neringa Bileišienė
- Clinic of Cardiac and Vascular Diseases, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Santariškių str. 2, LT-08661 Vilnius, Lithuania; (J.B.); (G.M.); (A.A.)
- Correspondence: ; Tel.: +370-614-28-588
| | - Jūratė Barysienė
- Clinic of Cardiac and Vascular Diseases, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Santariškių str. 2, LT-08661 Vilnius, Lithuania; (J.B.); (G.M.); (A.A.)
| | - Violeta Mikštienė
- Department of Human and Medical Genetics, Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, Santariskiu g. 2, LT-08661 Vilnius, Lithuania; (V.M.); (E.P.); (A.U.)
| | - Eglė Preikšaitienė
- Department of Human and Medical Genetics, Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, Santariskiu g. 2, LT-08661 Vilnius, Lithuania; (V.M.); (E.P.); (A.U.)
| | - Germanas Marinskis
- Clinic of Cardiac and Vascular Diseases, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Santariškių str. 2, LT-08661 Vilnius, Lithuania; (J.B.); (G.M.); (A.A.)
| | - Monika Keževičiūtė
- Center of Cardiology and Angiology, Vilnius University Hospital Santaros Klinikos, Santariskiu g. 2, LT-08661 Vilnius, Lithuania;
| | - Algirdas Utkus
- Department of Human and Medical Genetics, Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, Santariskiu g. 2, LT-08661 Vilnius, Lithuania; (V.M.); (E.P.); (A.U.)
| | - Audrius Aidietis
- Clinic of Cardiac and Vascular Diseases, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Santariškių str. 2, LT-08661 Vilnius, Lithuania; (J.B.); (G.M.); (A.A.)
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Proshlyakov AY, Chomakhidze PS, Novikova NA. Comparative Characteristics of Beta-Blockers in Patients with Congenital Long QT Syndrome. RATIONAL PHARMACOTHERAPY IN CARDIOLOGY 2021. [DOI: 10.20996/1819-6446-2021-06-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Congenital long QT syndrome is a pathology that requires special attention and knowledge about the safety and effectiveness of various medications. Prolongation of the QT interval due to congenital or acquired causes is an important factor in the development of an unfavorable life forecast with the formation of an elongated QT syndrome. With an unfavorable course, patients suffer from loss of consciousness, episodes of tachycardia. Often, stable polymorphic ventricular tachycardia develops. The risk of sudden cardiac death in this pathology can vary from 0.33% to 5%. In people who have suffered an episode of cardiac arrest, and do not have a permanent prescribed antiarrhythmic therapy, the mortality rate reaches 50% within 15 years. Preventive administration of antiarrhythmic drugs is not always effective. A positive result of treatment depends on the severity of long QT syndrome and its genotype. Beta-blockers are often prescribed to patients of different ages with various cardiac pathologies, including for the prevention of arrhythmia in long QT syndrome. Beta-blockers differ in various pharmacokinetic and pharmacodynamic parameters (lipophilicity/hydrophilicity, selectivity, presence/absence of internal sympathomimetic activity), which, along with the variant of the disease genotype, can affect their effectiveness and safety in the considered pathology. This review article presents the results of major studies on the safety and effectiveness of different groups of beta blockers in various variants of long QT syndrome. The preferred beta-blockers for various genotypes of the syndrome were determined, and a comparative characteristic of beta-blockers for their safety and preventive effectiveness was given.
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Affiliation(s)
- A. Yu. Proshlyakov
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
| | - P. Sh. Chomakhidze
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
| | - N. A. Novikova
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
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Abstract
The physiological heart function is controlled by a well-orchestrated interplay of different ion channels conducting Na+, Ca2+ and K+. Cardiac K+ channels are key players of cardiac repolarization counteracting depolarizating Na+ and Ca2+ currents. In contrast to Na+ and Ca2+, K+ is conducted by many different channels that differ in activation/deactivation kinetics as well as in their contribution to different phases of the action potential. Together with modulatory subunits these K+ channel α-subunits provide a wide range of repolarizing currents with specific characteristics. Moreover, due to expression differences, K+ channels strongly influence the time course of the action potentials in different heart regions. On the other hand, the variety of different K+ channels increase the number of possible disease-causing mutations. Up to now, a plethora of gain- as well as loss-of-function mutations in K+ channel forming or modulating proteins are known that cause severe congenital cardiac diseases like the long-QT-syndrome, the short-QT-syndrome, the Brugada syndrome and/or different types of atrial tachyarrhythmias. In this chapter we provide a comprehensive overview of different K+ channels in cardiac physiology and pathophysiology.
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Abstract
Long QT syndrome (LQTS) is a cardiovascular disorder characterized by an abnormality in cardiac repolarization leading to a prolonged QT interval and T-wave irregularities on the surface electrocardiogram. It is commonly associated with syncope, seizures, susceptibility to torsades de pointes, and risk for sudden death. LQTS is a rare genetic disorder and a major preventable cause of sudden cardiac death in the young. The availability of therapy for this lethal disease emphasizes the importance of early and accurate diagnosis. Additionally, understanding of the molecular mechanisms underlying LQTS could help to optimize genotype-specific treatments to prevent deaths in LQTS patients. In this review, we briefly summarize current knowledge regarding molecular underpinning of LQTS, in particular focusing on LQT1, LQT2, and LQT3, and discuss novel strategies to study ion channel dysfunction and drug-specific therapies in LQT1, LQT2, and LQT3 syndromes.
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Affiliation(s)
| | - Isabelle Deschênes
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
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Long QT Syndrome and Electrical Storm: Is Implanted Cardiac Defibrillator the Final Destination in Long QT Syndrome Management? COR ET VASA 2020. [DOI: 10.33678/cor.2020.076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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Long QT syndrome type 1 and 2 patients respond differently to arrhythmic triggers: The TriQarr in vivo study. Heart Rhythm 2020; 18:241-249. [PMID: 32882399 DOI: 10.1016/j.hrthm.2020.08.017] [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: 06/08/2020] [Revised: 08/21/2020] [Accepted: 08/27/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND In patients with long QT syndrome (LQTS), swimming and loud noises have been identified as genotype-specific arrhythmic triggers in LQTS type 1 (LQTS1) and LQTS type 2 (LQTS2), respectively. OBJECTIVE The purpose of this study was to compare LQTS group responses to arrhythmic triggers. METHODS LQTS1 and LQTS2 patients were included. Before and after beta-blocker intake, electrocardiograms were recorded as participants (1) were exposed to a loud noise of ∼100 dB; and (2) had their face immersed into cold water. RESULTS Twenty-three patients (9 LQTS1, 14 LQTS2) participated. In response to noise, LQTS groups showed similarly increased heart rate, but LQTS2 patients had corrected QT interval (Fridericia formula) (QTcF) prolonged significantly more than LQTS1 patients (37 ± 8 ms vs 15 ± 6 ms; P = .02). After intake of beta-blocker, QTcF prolongation in LQTS2 patients was significantly blunted and similar to that of LQTS1 patients (P = .90). In response to simulated diving, LQTS groups experienced a heart rate drop of ∼28 bpm, which shortened QTcF similarly in both groups. After intake of beta-blockers, heart rate dropped to 28 ± 2 bpm in LQTS1 patients and 20 ± 3 bpm in LQTS2, resulting in a slower heart rate in LQTS1 compared with LQTS2 (P = .01). In response, QTcF shortened similarly in LQTS1 and LQTS2 patients (57 ± 9 ms vs 36 ± 7 ms; P = .10). CONCLUSION When exposed to noise, LQTS2 patients had QTc prolonged significantly more than did LQTS1 patients. Importantly, beta-blockers reduced noise-induced QTc prolongation in LQTS2 patients, thus demonstrating the protective effect of beta-blockers. In response to simulated diving, LQTS groups responded similarly, but a slower heart rate was observed in LQTS1 patients during simulated diving after beta-blocker intake.
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Shah D, Prajapati C, Penttinen K, Cherian RM, Koivumäki JT, Alexanova A, Hyttinen J, Aalto-Setälä K. hiPSC-Derived Cardiomyocyte Model of LQT2 Syndrome Derived from Asymptomatic and Symptomatic Mutation Carriers Reproduces Clinical Differences in Aggregates but Not in Single Cells. Cells 2020; 9:cells9051153. [PMID: 32392813 PMCID: PMC7290503 DOI: 10.3390/cells9051153] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/29/2020] [Accepted: 05/02/2020] [Indexed: 12/13/2022] Open
Abstract
Mutations in the HERG gene encoding the potassium ion channel HERG, represent one of the most frequent causes of long QT syndrome type-2 (LQT2). The same genetic mutation frequently presents different clinical phenotypes in the family. Our study aimed to model LQT2 and study functional differences between the mutation carriers of variable clinical phenotypes. We derived human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) from asymptomatic and symptomatic HERG mutation carriers from the same family. When comparing asymptomatic and symptomatic single LQT2 hiPSC-CMs, results from allelic imbalance, potassium current density, and arrhythmicity on adrenaline exposure were similar, but a difference in Ca2+ transients was observed. The major differences were, however, observed at aggregate level with increased susceptibility to arrhythmias on exposure to adrenaline or potassium channel blockers on CM aggregates derived from the symptomatic individual. The effect of this mutation was modeled in-silico which indicated the reactivation of an inward calcium current as one of the main causes of arrhythmia. Our in-vitro hiPSC-CM model recapitulated major phenotype characteristics observed in LQT2 mutation carriers and strong phenotype differences between LQT2 asymptomatic vs. symptomatic were revealed at CM-aggregate level.
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Affiliation(s)
- Disheet Shah
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, 33520 Tampere, Finland; (C.P.); (K.P.); (R.M.C.); (J.T.K.); (A.A.); (J.H.); (K.A.-S.)
- Correspondence:
| | - Chandra Prajapati
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, 33520 Tampere, Finland; (C.P.); (K.P.); (R.M.C.); (J.T.K.); (A.A.); (J.H.); (K.A.-S.)
| | - Kirsi Penttinen
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, 33520 Tampere, Finland; (C.P.); (K.P.); (R.M.C.); (J.T.K.); (A.A.); (J.H.); (K.A.-S.)
| | - Reeja Maria Cherian
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, 33520 Tampere, Finland; (C.P.); (K.P.); (R.M.C.); (J.T.K.); (A.A.); (J.H.); (K.A.-S.)
| | - Jussi T. Koivumäki
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, 33520 Tampere, Finland; (C.P.); (K.P.); (R.M.C.); (J.T.K.); (A.A.); (J.H.); (K.A.-S.)
| | - Anna Alexanova
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, 33520 Tampere, Finland; (C.P.); (K.P.); (R.M.C.); (J.T.K.); (A.A.); (J.H.); (K.A.-S.)
| | - Jari Hyttinen
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, 33520 Tampere, Finland; (C.P.); (K.P.); (R.M.C.); (J.T.K.); (A.A.); (J.H.); (K.A.-S.)
| | - Katriina Aalto-Setälä
- Faculty of Medicine and Health Technology and BioMediTech Institute, Tampere University, 33520 Tampere, Finland; (C.P.); (K.P.); (R.M.C.); (J.T.K.); (A.A.); (J.H.); (K.A.-S.)
- Heart Hospital, Tampere University Hospital, 33520 Tampere, Finland
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14
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Brewer KR, Kuenze G, Vanoye CG, George AL, Meiler J, Sanders CR. Structures Illuminate Cardiac Ion Channel Functions in Health and in Long QT Syndrome. Front Pharmacol 2020; 11:550. [PMID: 32431610 PMCID: PMC7212895 DOI: 10.3389/fphar.2020.00550] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/09/2020] [Indexed: 12/13/2022] Open
Abstract
The cardiac action potential is critical to the production of a synchronized heartbeat. This electrical impulse is governed by the intricate activity of cardiac ion channels, among them the cardiac voltage-gated potassium (Kv) channels KCNQ1 and hERG as well as the voltage-gated sodium (Nav) channel encoded by SCN5A. Each channel performs a highly distinct function, despite sharing a common topology and structural components. These three channels are also the primary proteins mutated in congenital long QT syndrome (LQTS), a genetic condition that predisposes to cardiac arrhythmia and sudden cardiac death due to impaired repolarization of the action potential and has a particular proclivity for reentrant ventricular arrhythmias. Recent cryo-electron microscopy structures of human KCNQ1 and hERG, along with the rat homolog of SCN5A and other mammalian sodium channels, provide atomic-level insight into the structure and function of these proteins that advance our understanding of their distinct functions in the cardiac action potential, as well as the molecular basis of LQTS. In this review, the gating, regulation, LQTS mechanisms, and pharmacological properties of KCNQ1, hERG, and SCN5A are discussed in light of these recent structural findings.
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Affiliation(s)
- Kathryn R. Brewer
- Center for Structural Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN, United States
- Department of Biochemistry, Vanderbilt University, Nashville, TN, United States
| | - Georg Kuenze
- Center for Structural Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN, United States
- Department of Chemistry, Vanderbilt University, Nashville, TN, United States
| | - Carlos G. Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Alfred L. George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN, United States
- Department of Chemistry, Vanderbilt University, Nashville, TN, United States
- Department of Pharmacology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN, United States
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Charles R. Sanders
- Center for Structural Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN, United States
- Department of Biochemistry, Vanderbilt University, Nashville, TN, United States
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15
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Kistamás K, Veress R, Horváth B, Bányász T, Nánási PP, Eisner DA. Calcium Handling Defects and Cardiac Arrhythmia Syndromes. Front Pharmacol 2020; 11:72. [PMID: 32161540 PMCID: PMC7052815 DOI: 10.3389/fphar.2020.00072] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Calcium ions (Ca2+) play a major role in the cardiac excitation-contraction coupling. Intracellular Ca2+ concentration increases during systole and falls in diastole thereby determining cardiac contraction and relaxation. Normal cardiac function also requires perfect organization of the ion currents at the cellular level to drive action potentials and to maintain action potential propagation and electrical homogeneity at the tissue level. Any imbalance in Ca2+ homeostasis of a cardiac myocyte can lead to electrical disturbances. This review aims to discuss cardiac physiology and pathophysiology from the elementary membrane processes that can cause the electrical instability of the ventricular myocytes through intracellular Ca2+ handling maladies to inherited and acquired arrhythmias. Finally, the paper will discuss the current therapeutic approaches targeting cardiac arrhythmias.
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Affiliation(s)
- Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - Roland Veress
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - David A Eisner
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
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16
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Cernuda B, Fernandes CT, Allam SM, Orzillo M, Suppa G, Chia Chang Z, Athanasopoulos D, Buraei Z. The molecular determinants of R-roscovitine block of hERG channels. PLoS One 2019; 14:e0217733. [PMID: 31479461 PMCID: PMC6719874 DOI: 10.1371/journal.pone.0217733] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/17/2019] [Indexed: 02/06/2023] Open
Abstract
Human ether-à-go-go-related gene (Kv11.1, or hERG) is a potassium channel that conducts the delayed rectifier potassium current (IKr) during the repolarization phase of cardiac action potentials. hERG channels have a larger pore than other K+channels and can trap many unintended drugs, often resulting in acquired LQTS (aLQTS). R-roscovitine is a cyclin-dependent kinase (CDK) inhibitor that induces apoptosis in colorectal, breast, prostate, multiple myeloma, other cancer cell lines, and tumor xenografts, in micromolar concentrations. It is well tolerated in phase II clinical trials. R-roscovitine inhibits open hERG channels but does not become trapped in the pore. Two-electrode voltage clamp recordings from Xenopus oocytes expressing wild-type (WT) or hERG pore mutant channels (T623A, S624A, Y652A, F656A) demonstrated that compared to WT hERG, T623A, Y652A, and F656A inhibition by 200 μM R-roscovitine was ~ 48%, 29%, and 73% weaker, respectively. In contrast, S624A hERG was inhibited more potently than WT hERG, with a ~ 34% stronger inhibition. These findings were further supported by the IC50 values, which were increased for T623A, Y652A and F656A (by ~5.5, 2.75, and 42 fold respectively) and reduced 1.3 fold for the S624A mutant. Our data suggest that while T623, Y652, and F656 are critical for R-roscovitine-mediated inhibition, S624 may not be. Docking studies further support our findings. Thus, R-roscovitine’s relatively unique features, coupled with its tolerance in clinical trials, could guide future drug screens.
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Affiliation(s)
- Bryan Cernuda
- Department of Biology, Pace University, New York, NY, United States of America
| | | | - Salma Mohamed Allam
- Department of Biology, Pace University, New York, NY, United States of America
| | - Matthew Orzillo
- Department of Biology, Pace University, New York, NY, United States of America
| | - Gabrielle Suppa
- Department of Biology, Pace University, New York, NY, United States of America
| | - Zuleen Chia Chang
- Department of Biology, Pace University, New York, NY, United States of America
| | | | - Zafir Buraei
- Department of Biology, Pace University, New York, NY, United States of America
- * E-mail:
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17
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Alí A, Boutjdir M, Aromolaran AS. Cardiolipotoxicity, Inflammation, and Arrhythmias: Role for Interleukin-6 Molecular Mechanisms. Front Physiol 2019; 9:1866. [PMID: 30666212 PMCID: PMC6330352 DOI: 10.3389/fphys.2018.01866] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/11/2018] [Indexed: 12/12/2022] Open
Abstract
Fatty acid infiltration of the myocardium, acquired in metabolic disorders (obesity, type-2 diabetes, insulin resistance, and hyperglycemia) is critically associated with the development of lipotoxic cardiomyopathy. According to a recent Presidential Advisory from the American Heart Association published in 2017, the current average dietary intake of saturated free-fatty acid (SFFA) in the US is 11–12%, which is significantly above the recommended <10%. Increased levels of circulating SFFAs (or lipotoxicity) may represent an unappreciated link that underlies increased vulnerability to cardiac dysfunction. Thus, an important objective is to identify novel targets that will inform pharmacological and genetic interventions for cardiomyopathies acquired through excessive consumption of diets rich in SFFAs. However, the molecular mechanisms involved are poorly understood. The increasing epidemic of metabolic disorders strongly implies an undeniable and critical need to further investigate SFFA mechanisms. A rapidly emerging and promising target for modulation by lipotoxicity is cytokine secretion and activation of pro-inflammatory signaling pathways. This objective can be advanced through fundamental mechanisms of cardiac electrical remodeling. In this review, we discuss cardiac ion channel modulation by SFFAs. We further highlight the contribution of downstream signaling pathways involving toll-like receptors and pathological increases in pro-inflammatory cytokines. Our expectation is that if we understand pathological remodeling of major cardiac ion channels from a perspective of lipotoxicity and inflammation, we may be able to develop safer and more effective therapies that will be beneficial to patients.
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Affiliation(s)
- Alessandra Alí
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States.,Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Pharmacology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Mohamed Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States.,Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Pharmacology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Medicine, New York University School of Medicine, New York, NY, United States
| | - Ademuyiwa S Aromolaran
- Cardiovascular Research Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States.,Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Department of Pharmacology, State University of New York Downstate Medical Center, Brooklyn, NY, United States
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18
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2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Heart Rhythm 2018; 15:e73-e189. [DOI: 10.1016/j.hrthm.2017.10.036] [Citation(s) in RCA: 177] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Indexed: 02/07/2023]
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19
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Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB, Deal BJ, Dickfeld T, Field ME, Fonarow GC, Gillis AM, Granger CB, Hammill SC, Hlatky MA, Joglar JA, Kay GN, Matlock DD, Myerburg RJ, Page RL. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation 2018; 138:e272-e391. [PMID: 29084731 DOI: 10.1161/cir.0000000000000549] [Citation(s) in RCA: 249] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
| | - William G Stevenson
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Michael J Ackerman
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - William J Bryant
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - David J Callans
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Anne B Curtis
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Barbara J Deal
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Timm Dickfeld
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Michael E Field
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Gregg C Fonarow
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Anne M Gillis
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Christopher B Granger
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Stephen C Hammill
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Mark A Hlatky
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - José A Joglar
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - G Neal Kay
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Daniel D Matlock
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Robert J Myerburg
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Richard L Page
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
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20
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Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB, Deal BJ, Dickfeld T, Field ME, Fonarow GC, Gillis AM, Granger CB, Hammill SC, Hlatky MA, Joglar JA, Kay GN, Matlock DD, Myerburg RJ, Page RL. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation 2018; 138:e210-e271. [PMID: 29084733 DOI: 10.1161/cir.0000000000000548] [Citation(s) in RCA: 151] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - William G Stevenson
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Michael J Ackerman
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - William J Bryant
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - David J Callans
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Anne B Curtis
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Barbara J Deal
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Timm Dickfeld
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Michael E Field
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Gregg C Fonarow
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Anne M Gillis
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Christopher B Granger
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Stephen C Hammill
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Mark A Hlatky
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - José A Joglar
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - G Neal Kay
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Daniel D Matlock
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Robert J Myerburg
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
| | - Richard L Page
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. Section numbers pertain to those in the full-text guideline. †ACC/AHA Representative. ‡HRS Representative. §ACC/AHA Task Force on Performance Measures Liaison/HFSA Representative. ‖ACC/AHA Task Force on Clinical Practice Guidelines Liaison
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Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB, Deal BJ, Dickfeld T, Field ME, Fonarow GC, Gillis AM, Granger CB, Hammill SC, Hlatky MA, Joglar JA, Kay GN, Matlock DD, Myerburg RJ, Page RL. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2018; 72:e91-e220. [PMID: 29097296 DOI: 10.1016/j.jacc.2017.10.054] [Citation(s) in RCA: 696] [Impact Index Per Article: 116.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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22
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Champéroux P, Fesler P, Judé S, Richard S, Le Guennec JY, Thireau J. High-frequency autonomic modulation: a new model for analysis of autonomic cardiac control. Br J Pharmacol 2018; 175:3131-3143. [PMID: 29723392 PMCID: PMC6031873 DOI: 10.1111/bph.14354] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 04/18/2018] [Accepted: 04/24/2018] [Indexed: 12/19/2022] Open
Abstract
Background and Purpose Increase in high‐frequency beat‐to‐beat heart rate oscillations by torsadogenic hERG blockers appears to be associated with signs of parasympathetic and sympathetic co‐activation which cannot be assessed directly using classic methods of heart rate variability analysis. The present work aimed to find a translational model that would allow this particular state of the autonomic control of heart rate to be assessed. Experimental Approach High‐frequency heart rate and heart period oscillations were analysed within discrete 10 s intervals in a cohort of 200 healthy human subjects. Results were compared to data collected in non‐human primates and beagle dogs during pharmacological challenges and torsadogenic hERG blockers exposure, in 127 genotyped LQT1 patients on/off β‐blocker treatment and in subgroups of smoking and non‐smoking subjects. Key Results Three states of autonomic modulation, S1 (parasympathetic predominance) to S3 (reciprocal parasympathetic withdrawal/sympathetic activation), were differentiated to build a new model of heart rate variability referred to as high‐frequency autonomic modulation. The S2 state corresponded to a specific state during which both parasympathetic and sympathetic systems were coexisting or co‐activated. S2 oscillations were proportionally increased by torsadogenic hERG‐blocking drugs, whereas smoking caused an increase in S3 oscillations. Conclusions and Implications The combined analysis of the magnitude of high‐frequency heart rate and high‐frequency heart period oscillations allows a refined assessment of heart rate autonomic modulation applicable to long‐term ECG recordings and offers new approaches to assessment of the risk of sudden death both in terms of underlying mechanisms and sensitivity.
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Affiliation(s)
| | - Pierre Fesler
- Department of Internal Medicine, Hopital Lapeyronie, Montpellier, France.,Laboratoire PHYMEDEXP,INSERM U1046, CNRS UMR 9214, Université de Montpellier, CHU Arnaud de Villeneuve, Montpellier Cedex 05, 34295, France
| | - Sebastien Judé
- Centre de Recherches Biologiques, CERB, Baugy, 18800, France
| | - Serge Richard
- Centre de Recherches Biologiques, CERB, Baugy, 18800, France
| | - Jean-Yves Le Guennec
- Laboratoire PHYMEDEXP,INSERM U1046, CNRS UMR 9214, Université de Montpellier, CHU Arnaud de Villeneuve, Montpellier Cedex 05, 34295, France
| | - Jérôme Thireau
- Laboratoire PHYMEDEXP,INSERM U1046, CNRS UMR 9214, Université de Montpellier, CHU Arnaud de Villeneuve, Montpellier Cedex 05, 34295, France
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Shah SR, Park K, Alweis R. Long QT Syndrome: A Comprehensive Review of the Literature and Current Evidence. Curr Probl Cardiol 2018; 44:92-106. [PMID: 29784533 DOI: 10.1016/j.cpcardiol.2018.04.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 04/29/2018] [Indexed: 01/02/2023]
Abstract
Long QT syndrome (LQT) represents a heterogeneous family of cardiac electrophysiologic disorders characterized by QT prolongation and T-wave abnormalities on the electrocardiogram. It is commonly associated with syncope, however, sudden cardiac death can occur due to torsades de pointes. LQT is a clinical diagnosis and should be suspected in individuals on the basis of clinical presentation, family history and ECG characteristics. Management is focused on the prevention of syncope and ultimately sudden death. Complete cessation of symptoms is the goal. Life-style modification, beta blockers and ICD implantation are the most important therapeutic modalities in proper management of patients with LQT. Awareness should be raised regarding possible circumstances that could increase the risk of QT prolongation. Advanced age, hypokalemia, a history of heart failure, and structural heart disease are often mentioned in this context. Prudent consideration is needed before making a decision to recommend an ICD implantation in a young, active patient. Medical and/or device therapy still represent important therapeutic modalities in the management of patients with LQT with careful clinical judgement for the substrate of patients who will benefit. Insights from benchside to bedside have facilitated progress toward better therapeutic strategies, there also remains a need for tailoring management toward individuals in a mechanism-specific manner to optimize care. In addition, continued progress toward fundamental understanding of mechanisms of ion channel function and drug-channel interaction will guide the development of more effective, mechanism-based molecular agents in the treatment of LQT.
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Non-sustained microvolt level T-wave alternans in congenital long QT syndrome types 1 and 2. J Electrocardiol 2017; 51:303-308. [PMID: 29183619 DOI: 10.1016/j.jelectrocard.2017.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Indexed: 11/23/2022]
Abstract
BACKGROUND Patients with long QT syndrome (LQTS) are predisposed to polymorphic ventricular tachycardia (VT) during adrenergic stimulation. Microvolt T-wave alternans (MTWA) is linked to vulnerability to VT in structural heart disease. The prevalence of non-sustained MTWA (NS-MTWA) in LQTS is unknown. METHODS 31 LQT1, 42 LQT2, and 80 controls underwent MTWA testing during exercise. MTWA tests were classified per standardized criteria, and re-analyzed according to the modified criteria to account for NS-MTWA. RESULTS LQT1 and LQT2 patients had a significantly higher frequency of late NS-MTWA (26% and 12%) compared to controls (0%). There was no significant difference between the groups with respect to sustained and early NS-MTWA. Late NS-MTWA was significantly associated with QTc. CONCLUSION LQT1 and LQT2 patients had a higher prevalence of late NS-MTWA during exercise than matched controls. NS-MTWA likely reflects transient adrenergically mediated dispersion of repolarization, and could be a marker of arrhythmic risk in LQTS.
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25
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Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB, Deal BJ, Dickfeld T, Field ME, Fonarow GC, Gillis AM, Granger CB, Hammill SC, Hlatky MA, Joglar JA, Kay GN, Matlock DD, Myerburg RJ, Page RL. 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: Executive summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm 2017; 15:e190-e252. [PMID: 29097320 DOI: 10.1016/j.hrthm.2017.10.035] [Citation(s) in RCA: 381] [Impact Index Per Article: 54.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Indexed: 12/23/2022]
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26
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Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB, Deal BJ, Dickfeld T, Field ME, Fonarow GC, Gillis AM, Granger CB, Hammill SC, Hlatky MA, Joglar JA, Kay GN, Matlock DD, Myerburg RJ, Page RL. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2017; 72:1677-1749. [PMID: 29097294 DOI: 10.1016/j.jacc.2017.10.053] [Citation(s) in RCA: 249] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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27
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Ahn J, Kim HJ, Choi JI, Lee KN, Shim J, Ahn HS, Kim YH. Effectiveness of beta-blockers depending on the genotype of congenital long-QT syndrome: A meta-analysis. PLoS One 2017; 12:e0185680. [PMID: 29059199 PMCID: PMC5653191 DOI: 10.1371/journal.pone.0185680] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 09/17/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Beta-blockers are first-line therapy in patients with congenital long-QT syndrome (LQTS). OBJECTIVE This study sought to determine the differences in effectiveness of beta-blockers on risk reduction according to LQTS genotype. METHODS We searched MEDLINE, EMBASE, and CENTRAL databases to investigate the use of beta-blockers (atenolol, nadolol, propranolol, and metoprolol) in patients with LQTS. Hazard ratio (HR) and relative risk (RR) were extracted or calculated from studies reporting cardiac events (syncope, aborted cardiac arrest (ACA), or sudden cardiac death (SCD)). RESULTS Among 2,113 articles searched, 10 studies (7 registry-based cohort studies (Cohort) and 3 interrupted time series studies (ITS)) involving 9,727 patients were included. In a meta-analysis using a random-effect model, the use of beta-blocker was associated with significant risk reduction of all cardiac events (HR 0.49, p<0.001 in Cohort; RR 0.39, p<0.001 in ITS) and serious cardiac events (ACA or SCD) (HR 0.47, p<0.001 in Cohort). In both LQT1 and LQT2, the risk was reduced with beta-blocker therapy in Cohort (HR 0.59 in LQT1; HR 0.39 in LQT2) as well as ITS (RR 0.29 in LQT1; RR 0.48 in LQT2). Among the beta-blockers, nadolol showed a significant risk reduction in both LQT1 and LQT2 (HR 0.47 and 0.27, respectively), whereas atenolol and propranolol decreased the risk only in LQT1 (HR 0.36 and 0.46, respectively). Metoprolol showed no significant reduction in either genotype. In LQT3, beta-blocker therapy was not as effective as LQT1 or LQT2; however, it was inconclusive due to data insufficiency. CONCLUSION This meta-analysis showed that beta-blockers were effective in reducing risk of cardiac events in patients with LQTS. Among them, nadolol was effective in LQT1 and LQT2, whereas other drugs showed different effectiveness depending on LQT genotype.
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Affiliation(s)
- Jinhee Ahn
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine and Korea University Medical Center, Seoul, Republic of Korea
- Division of Cardiology, Department of Internal Medicine, Pusan National University Hospital, Busan, Republic of Korea
| | - Hyun Jung Kim
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jong-Il Choi
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine and Korea University Medical Center, Seoul, Republic of Korea
| | - Kwang No Lee
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine and Korea University Medical Center, Seoul, Republic of Korea
| | - Jaemin Shim
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine and Korea University Medical Center, Seoul, Republic of Korea
| | - Hyeong Sik Ahn
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Republic of Korea
| | - Young-Hoon Kim
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine and Korea University Medical Center, Seoul, Republic of Korea
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28
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Page A, McNitt S, Xia X, Zareba W, Couderc JP. Population-based beat-to-beat QT analysis from Holter recordings in the long QT syndrome. J Electrocardiol 2017; 50:787-791. [PMID: 28919217 DOI: 10.1016/j.jelectrocard.2017.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Indexed: 11/20/2022]
Abstract
The increasing dissemination of wearable ECG recorders (e.g. Holter, patches, and strap sensors) enables the acquisition of large amounts of data during long periods of time. However, the clinical value of these long-term continuous recordings is hindered by the lack of automatic tools to extract clinically relevant information (other than non-sinus and life-threatening rhythms) from such long-term data, particularly when targeting population-based research. In this work, we propose and test a new tool for analyzing beat-to-beat interval measurements and extracting features from Holter ECGs. Specifically, we assess the adaptation of the QT interval following sudden changes in heart rate in the primary long QT types (1 & 2). We find that in long QT syndrome type 2, certain QT adaptation patterns can indicate a higher risk for cardiac events.
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Affiliation(s)
- Alex Page
- Heart Research Follow-up Program, Cardiology Department, University of Rochester Medical Center, Rochester, NY, United States.
| | - Scott McNitt
- Heart Research Follow-up Program, Cardiology Department, University of Rochester Medical Center, Rochester, NY, United States
| | - Xiaojuan Xia
- Heart Research Follow-up Program, Cardiology Department, University of Rochester Medical Center, Rochester, NY, United States
| | - Wojciech Zareba
- Heart Research Follow-up Program, Cardiology Department, University of Rochester Medical Center, Rochester, NY, United States
| | - Jean-Philippe Couderc
- Heart Research Follow-up Program, Cardiology Department, University of Rochester Medical Center, Rochester, NY, United States
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29
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El-Sherif N, Turitto G, Boutjdir M. Congenital Long QT syndrome and torsade de pointes. Ann Noninvasive Electrocardiol 2017; 22. [PMID: 28670758 DOI: 10.1111/anec.12481] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 05/19/2017] [Indexed: 12/19/2022] Open
Abstract
Since its initial description by Jervell and Lange-Nielsen in 1957, the congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. A prolonged QT interval in the surface electrocardiogram is the sine qua non of the LQTS and is a surrogate measure of the ventricular action potential duration (APD). Congenital as well as acquired alterations in certain cardiac ion channels can affect their currents in such a way as to increase the APD and hence the QT interval. The inhomogeneous lengthening of the APD across the ventricular wall results in dispersion of APD. This together with the tendency of prolonged APD to be associated with oscillations at the plateau level, termed early afterdepolarizations (EADs), provides the substrate of ventricular tachyarrhythmia associated with LQTS, usually referred to as torsade de pointes (TdP) VT. This review will discuss the genetic, molecular, and phenotype characteristics of congenital LQTS as well as current management strategies and future directions in the field.
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Affiliation(s)
- Nabil El-Sherif
- Downstate Medical Center, State University of New York, Brooklyn, NY, USA.,VA NY Harbor Healthcare System, Brooklyn, NY, USA
| | - Gioia Turitto
- NewYork-Presbyterian Brooklyn Methodist Hospital, New York, NY, USA
| | - Mohamed Boutjdir
- Downstate Medical Center, State University of New York, Brooklyn, NY, USA.,VA NY Harbor Healthcare System, Brooklyn, NY, USA.,NYU School of Medicine, New York, NY, USA
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30
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Yang PC, Perissinotti LL, López-Redondo F, Wang Y, DeMarco KR, Jeng MT, Vorobyov I, Harvey RD, Kurokawa J, Noskov SY, Clancy CE. A multiscale computational modelling approach predicts mechanisms of female sex risk in the setting of arousal-induced arrhythmias. J Physiol 2017; 595:4695-4723. [PMID: 28516454 PMCID: PMC5509858 DOI: 10.1113/jp273142] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 04/24/2017] [Indexed: 01/10/2023] Open
Abstract
KEY POINTS This study represents a first step toward predicting mechanisms of sex-based arrhythmias that may lead to important developments in risk stratification and may inform future drug design and screening. We undertook simulations to reveal the conditions (i.e. pacing, drugs, sympathetic stimulation) required for triggering and sustaining reentrant arrhythmias. Using the recently solved cryo-EM structure for the Eag-family channel as a template, we revealed potential interactions of oestrogen with the pore loop hERG mutation (G604S). Molecular models suggest that oestrogen and dofetilide blockade can concur simultaneously in the hERG channel pore. ABSTRACT Female sex is a risk factor for inherited and acquired long-QT associated torsade de pointes (TdP) arrhythmias, and sympathetic discharge is a major factor in triggering TdP in female long-QT syndrome patients. We used a combined experimental and computational approach to predict 'the perfect storm' of hormone concentration, IKr block and sympathetic stimulation that induces arrhythmia in females with inherited and acquired long-QT. More specifically, we developed mathematical models of acquired and inherited long-QT syndrome in male and female ventricular human myocytes by combining effects of a hormone and a hERG blocker, dofetilide, or hERG mutations. These 'male' and 'female' model myocytes and tissues then were used to predict how various sex-based differences underlie arrhythmia risk in the setting of acute sympathetic nervous system discharge. The model predicted increased risk for arrhythmia in females when acute sympathetic nervous system discharge was applied in the settings of both inherited and acquired long-QT syndrome. Females were predicted to have protection from arrhythmia induction when progesterone is high. Males were protected by the presence of testosterone. Structural modelling points towards two plausible and distinct mechanisms of oestrogen action enhancing torsadogenic effects: oestradiol interaction with hERG mutations in the pore loop containing G604 or with common TdP-related blockers in the intra-cavity binding site. Our study presents findings that constitute the first evidence linking structure to function mechanisms underlying female dominance of arousal-induced arrhythmias.
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Affiliation(s)
- Pei-Chi Yang
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Laura L Perissinotti
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Fernando López-Redondo
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University
| | - Yibo Wang
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Kevin R DeMarco
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Mao-Tsuen Jeng
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Igor Vorobyov
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Robert D Harvey
- Department of Pharmacology, University of Nevada, Reno, NV, USA
| | - Junko Kurokawa
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University.,Department of Bio-informational Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Sergei Y Noskov
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Colleen E Clancy
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
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Bohnen MS, Peng G, Robey SH, Terrenoire C, Iyer V, Sampson KJ, Kass RS. Molecular Pathophysiology of Congenital Long QT Syndrome. Physiol Rev 2017; 97:89-134. [PMID: 27807201 PMCID: PMC5539372 DOI: 10.1152/physrev.00008.2016] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ion channels represent the molecular entities that give rise to the cardiac action potential, the fundamental cellular electrical event in the heart. The concerted function of these channels leads to normal cyclical excitation and resultant contraction of cardiac muscle. Research into cardiac ion channel regulation and mutations that underlie disease pathogenesis has greatly enhanced our knowledge of the causes and clinical management of cardiac arrhythmia. Here we review the molecular determinants, pathogenesis, and pharmacology of congenital Long QT Syndrome. We examine mechanisms of dysfunction associated with three critical cardiac currents that comprise the majority of congenital Long QT Syndrome cases: 1) IKs, the slow delayed rectifier current; 2) IKr, the rapid delayed rectifier current; and 3) INa, the voltage-dependent sodium current. Less common subtypes of congenital Long QT Syndrome affect other cardiac ionic currents that contribute to the dynamic nature of cardiac electrophysiology. Through the study of mutations that cause congenital Long QT Syndrome, the scientific community has advanced understanding of ion channel structure-function relationships, physiology, and pharmacological response to clinically employed and experimental pharmacological agents. Our understanding of congenital Long QT Syndrome continues to evolve rapidly and with great benefits: genotype-driven clinical management of the disease has improved patient care as precision medicine becomes even more a reality.
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Affiliation(s)
- M S Bohnen
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - G Peng
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - S H Robey
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - C Terrenoire
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - V Iyer
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - K J Sampson
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - R S Kass
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
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32
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The evolution of sports participation guidelines and the influence of genotype–phenotype correlation in long QT syndrome. Trends Cardiovasc Med 2016; 26:690-697. [DOI: 10.1016/j.tcm.2016.04.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 04/29/2016] [Accepted: 04/29/2016] [Indexed: 01/02/2023]
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33
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Cho Y. Management of Patients with Long QT Syndrome. Korean Circ J 2016; 46:747-752. [PMID: 27826330 PMCID: PMC5099327 DOI: 10.4070/kcj.2016.46.6.747] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/19/2016] [Accepted: 03/22/2016] [Indexed: 01/02/2023] Open
Abstract
Long QT syndrome (LQTS) is a rare cardiac channelopathy associated with syncope and sudden death due to torsades de pointes and ventricular fibrillation. Syncope and sudden death are frequently associated with physical and emotional stress. Management of patients with LQTS consists of life-style modification, β-blockers, left cardiac sympathetic denervation (LCSD), and implantable cardioverter-defibrillator (ICD) implantation. Prohibition of competitive exercise and avoidance of QT-prolonging drugs are important issues in life-style modification. Although β-blockers are the primary treatment modality for patients with LQTS, these drugs are not completely effective in some patients. Lifelong ICD implantation in young and active patients is associated with significant complications. LCSD is a relatively simple and highly effective surgical procedure. However, LCSD is rarely used.
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Affiliation(s)
- Yongkeun Cho
- Department of Internal Medicine, Kyungpook National Univeristy Hospital, Daegu, Korea
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34
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Cheung CC, Laksman ZWM, Mellor G, Sanatani S, Krahn AD. Exercise and Inherited Arrhythmias. Can J Cardiol 2016; 32:452-8. [PMID: 26927864 DOI: 10.1016/j.cjca.2016.01.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 12/29/2015] [Accepted: 01/06/2016] [Indexed: 01/11/2023] Open
Abstract
Sudden cardiac death (SCD) in an apparently healthy individual is a tragedy that prompts a series of investigations to identify the cause of death and to prevent SCD in potentially at-risk family members. Several inherited channelopathies and cardiomyopathies, including long QT syndrome (LQTS), catecholaminergic polymorphic ventricular cardiomyopathy (CPVT), hypertrophic cardiomyopathy (HCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC) are associated with exercise-related SCD. Exercise restriction has been a historical mainstay of therapy for these conditions. Syncope and cardiac arrest occur during exercise in LQTS and CPVT because of ventricular arrhythmias, which are managed with β-blockade and exercise restriction. Exercise may provoke hemodynamic or ischemic changes in HCM, leading to ventricular arrhythmias. ARVC is a disease of the desmosome, whose underlying disease process is accelerated by exercise. On this basis, expert consensus has erred on the side of caution, recommending rigorous exercise restriction for all inherited arrhythmias. With time, as familiarity with inherited arrhythmia conditions has increased and patients with milder forms of disease are diagnosed, practitioners have questioned the historical rigorous restrictions advocated for all. This change has been driven by the fact that these are often children and young adults who wish to lead active lives. Recent evidence suggests a lower risk of exercise-related arrhythmias in treated patients than was previously assumed, including those with previous symptoms managed with an implantable cardioverter-defibrillator. In this review, we emphasize shared decision making, monitored medical therapy, individual and team awareness of precautions and emergency response measures, and a more permissive approach to recreational and competitive exercise.
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Affiliation(s)
- Christopher C Cheung
- Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Zachary W M Laksman
- Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gregory Mellor
- Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shubhayan Sanatani
- Children's Heart Centre, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Andrew D Krahn
- Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada.
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Fenotipo heterogéneo del síndrome de QT largo causado por la mutación KCNH2-H562R: importancia del estudio genético familiar. Rev Esp Cardiol 2015. [DOI: 10.1016/j.recesp.2014.10.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Abstract
In the last decade, there have been considerable advances in the understanding of the pathophysiology of malignant ventricular tachyarrhythmias (VT) and sudden cardiac death (SCD). Over 80% of SCD occurs in patients with organic heart disease. However, approximately 10%-15% of SCD occurs in the presence of structurally normal heart, and the majority of these patients are young. In this group of patients, changes in genes encoding cardiac ion channels produce modifications of the function of the channel resulting in an electrophysiological substrate of VT and SCD. Collectively, these disorders are referred to as cardiac ion channelopathies. The four major syndromes in this group are: the long QT syndrome (LQTS), the Brugada syndrome (BrS), the short QT syndrome (SQTS), and the catecholaminergic polymorphic ventricular tachycardia (CPVT). Each of these syndromes includes multiple subtypes with different and sometimes complex cardiac ion channel genetic abnormalities. Many are associated with other somatic and neurological abnormalities besides the risk of VT and SCD. The current management of cardiac ion channelopathies can be summarized as follows: (1) in symptomatic patients, the implantable cardioverter defibrillator (ICD) is the only viable option; (2) in asymptomatic patients, risk stratification is necessary, followed by either the ICD, pharmacotherapy, or a combination of both. A genotype-specific approach to pharmacotherapy requires a thorough understanding of the molecular-cellular basis of arrhythmogenesis in cardiac ion channelopathies as well as the specific drug profile.
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Farrugia A, Keyser C, Hollard C, Raul J, Muller J, Ludes B. Targeted next generation sequencing application in cardiac channelopathies: Analysis of a cohort of autopsy-negative sudden unexplained deaths. Forensic Sci Int 2015; 254:5-11. [DOI: 10.1016/j.forsciint.2015.06.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 05/22/2015] [Accepted: 06/24/2015] [Indexed: 12/19/2022]
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Koponen M, Marjamaa A, Hiippala A, Happonen JM, Havulinna AS, Salomaa V, Lahtinen AM, Hintsa T, Viitasalo M, Toivonen L, Kontula K, Swan H. Follow-up of 316 molecularly defined pediatric long-QT syndrome patients: clinical course, treatments, and side effects. Circ Arrhythm Electrophysiol 2015; 8:815-23. [PMID: 26063740 DOI: 10.1161/circep.114.002654] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 05/26/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Inherited long-QT syndrome (LQTS) is associated with risk of sudden death. We assessed the clinical course and the fulfillment of current treatment strategies in molecularly defined pediatric LQTS type 1 and (LQT1) and type 2 (LQT2) patients. METHODS AND RESULTS Follow-up data covering a mean of 12 years were collected for 316 genotyped LQT1 and LQT2 patients aged 0 to 18 years. No arrhythmic deaths occurred during the follow-up. Finnish KCNQ1 and KCNH2 founder mutations were associated with fewer cardiac events than other KCNQ1 and KCNH2 mutations (hazard ratio [HR], 0.33; P=0.03 and HR, 0.16; P=0.01, respectively). QTc interval ≥500 ms increased the risk of cardiac events compared with QTc <470 ms (HR, 3.32; P=0.001). Treatment with β-blocker medication was associated with reduced risk of first cardiac event (HR, 0.23; P=0.001). Noncompliant LQT2 patients were more often symptomatic than compliant LQT2 patients (18% and 0%, respectively; P=0.03). Treatment with implantable cardioverter defibrillator was rare (3%) and resulted in reinterventions in 44% of cases. CONCLUSIONS Severe cardiac events are uncommon in molecularly defined and appropriately treated pediatric LQTS mutation carriers. β-Blocker medication reduces the risk of cardiac events and is generally well tolerated in this age group of LQTS patients.
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Affiliation(s)
- Mikael Koponen
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.).
| | - Annukka Marjamaa
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Anita Hiippala
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Juha-Matti Happonen
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Aki S Havulinna
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Veikko Salomaa
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Annukka M Lahtinen
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Taina Hintsa
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Matti Viitasalo
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Lauri Toivonen
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Kimmo Kontula
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
| | - Heikki Swan
- From the Heart and Lung Center, Helsinki University Central Hospital (M.K., A.M., M.V., L.T., H.S.), Children's Hospital, Helsinki University Central Hospital (A.H., J.-M.H.), Department of Medicine, Helsinki University Central Hospital (A.M.L., K.K.), and Institute of Behavioural Sciences, Psychology (T.H.), University of Helsinki, Helsinki, Finland; and Department of Health, National Institute for Health and Welfare, Helsinki, Finland (A.S.H., V.S.)
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Tadros R, Cadrin-Tourigny J, Abadir S, Rivard L, Nattel S, Talajic M, Khairy P. Pharmacotherapy for inherited arrhythmia syndromes: mechanistic basis, clinical trial evidence and practical application. Expert Rev Cardiovasc Ther 2015; 13:769-82. [DOI: 10.1586/14779072.2015.1049156] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Muñoz-Esparza C, García-Molina E, Salar-Alcaraz M, Peñafiel-Verdú P, Sánchez-Muñoz JJ, Martínez Sánchez J, Cabañas-Perianes V, Valdés Chávarri M, García Alberola A, Gimeno-Blanes JR. Heterogeneous Phenotype of Long QT Syndrome Caused by the KCNH2-H562R Mutation: Importance of Familial Genetic Testing. ACTA ACUST UNITED AC 2015; 68:861-8. [PMID: 25819988 DOI: 10.1016/j.rec.2014.10.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 10/27/2014] [Indexed: 11/15/2022]
Abstract
INTRODUCTION AND OBJECTIVES Long QT syndrome is an inherited ion channelopathy that leads to syncope and sudden death. Because of the heterogeneous phenotype of this disease, genetic testing is fundamental to detect individuals with concealed long QT syndrome. In this study, we determined the features of a family with 13 carriers of the KCNH2-H562R missense mutation, which affects the pore region of the HERG channel. METHODS We identified the KCNH2-H562R mutation in a 65-year-old man with a prolonged QTc interval who had experienced an episode of torsade de pointes. Subsequently, a total of 13 mutation carriers were identified in the family. Carriers (age 48 [26] years; 46% males) underwent clinical evaluation, electrocardiography and echocardiography. RESULTS The mean (standard deviation) QTc in carriers was 493 (42) ms (3 [23%] showed normal QTc); 6 (46%) had symptoms (4, syncope; 1, sudden death; 1, aborted sudden death [proband]). While under treatment with beta-blockers, 11 of 12 carriers (92%) remained asymptomatic at 5 years of follow-up (1 patient required left cardiac sympathectomy). The QTc shortening with beta-blockers was 50 (37) ms. There was 1 sudden death in a patient who refused treatment. CONCLUSIONS Family study is essential in the interpretation of a genetic testing result. This article describes the heterogeneous and variable phenotype of a large family with the KCNH2-H562R mutation and highlights the role of genetic study for the appropriate identification of at-risk individuals who would benefit from treatment.
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Affiliation(s)
- Carmen Muñoz-Esparza
- Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Esperanza García-Molina
- Servicio de Análisis Clínicos, Hospital Clínico Universitario Virgen de la Arrixaca, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Mariela Salar-Alcaraz
- Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Pablo Peñafiel-Verdú
- Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Juan J Sánchez-Muñoz
- Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Juan Martínez Sánchez
- Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Valentín Cabañas-Perianes
- Servicio de Hematología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Mariano Valdés Chávarri
- Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Arcadio García Alberola
- Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Juan R Gimeno-Blanes
- Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain.
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O-Uchi J, Rice JJ, Ruwald MH, Parks XX, Ronzier E, Moss AJ, Zareba W, Lopes CM. Impaired IKs channel activation by Ca(2+)-dependent PKC shows correlation with emotion/arousal-triggered events in LQT1. J Mol Cell Cardiol 2014; 79:203-11. [PMID: 25479336 DOI: 10.1016/j.yjmcc.2014.11.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 10/23/2014] [Accepted: 11/12/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND The most common inherited cardiac arrhythmia, LQT1, is due to IKs potassium channel mutations and is linked to high risk of adrenergic-triggered cardiac events. We recently showed that although exercise-triggered events are very well treated by ß-blockers for these patients, acute arousal-triggered event rate were not significantly reduced after beta-blocker treatment, suggesting that the mechanisms underlying arousal-triggered arrhythmias may be different from those during exercise. IKs is strongly regulated by β-adrenergic receptor (β-AR) signaling, but little is known about the role of α1-AR-mediated regulation. METHODS AND RESULTS Here we show, using a combination of cellular electrophysiology and computational modeling, that IKs phosphorylation and α1-AR regulation via activation of calcium-dependent PKC isoforms (cPKC) may be a key mechanism to control channel voltage-dependent activation and consequently action potential duration (APD) in response to adrenergic-stimulus. We show that simulated mutation-specific combined adrenergic effects (β+α) on APD were strongly correlated to acute stress-triggered cardiac event rate for patients while β-AR effects alone were not. CONCLUSION We were able to show that calcium-dependent PKC signaling is key to normal QT shortening during acute arousal and when impaired, correlates with increased rate of sudden arousal-triggered cardiac events. Our study suggests that the acute α1-AR-cPKC regulation of IKs is important for QT shortening in "fight-or-flight" response and is linked to decreased risk of sudden emotion/arousal-triggered cardiac events in LQT1 patients.
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Affiliation(s)
- Jin O-Uchi
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - J Jeremy Rice
- Functional Genomics and Systems Biology Group, IBM T.J. Watson Research Center, New York, USA
| | - Martin H Ruwald
- Cardiology Division, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Xiaorong Xu Parks
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Elsa Ronzier
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Arthur J Moss
- Cardiology Division, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Wojciech Zareba
- Cardiology Division, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Coeli M Lopes
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA.
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Barsheshet A, Dotsenko O, Goldenberg I. Congenital long QT syndromes: prevalence, pathophysiology and management. Paediatr Drugs 2014; 16:447-56. [PMID: 25288402 DOI: 10.1007/s40272-014-0090-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Long QT syndrome is a genetic disorder associated with life threatening ventricular arrhythmias and sudden death. This inherited arrhythmic disorder exhibits genetic heterogeneity, incomplete penetrance, and variable expressivity. During the past two decades there have been major advancements in understanding the genotype-phenotype correlations in LQTS. This genotype-phenotype relationship can lead to improved management of LQTS. However, development of genotype-specific or mutation-specific management strategies is very challenging. This review describes the pathophysiology of LQTS, genotype-phenotype correlations, and focuses on the management of LQTS. In general, the treatment of LQTS consists of lifestyle modifications, medical therapy with beta-blockers, device and surgical therapy. We further summarize current data on the efficacy of pharmacological treatment options for the three most prevalent LQTS variants including beta-blockers in LQT1, LQT2 and LQT3, sodium channel blockers and ranolazine for LQT3, potassium supplementation and spironolactone for LQT2, and possibly sex hormone-based therapy for LQT2.
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Affiliation(s)
- Alon Barsheshet
- Cardiology Department, Rabin Medical Center, Petach Tikva, Israel
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Unmasking of familial long QT syndrome type 2 with crystal methamphetamine exposure. Heart Rhythm 2014; 11:1836-8. [PMID: 24882508 DOI: 10.1016/j.hrthm.2014.05.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Indexed: 11/20/2022]
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Barsheshet A, Dotsenko O, Goldenberg I. Genotype-specific risk stratification and management of patients with long QT syndrome. Ann Noninvasive Electrocardiol 2013; 18:499-509. [PMID: 24206565 DOI: 10.1111/anec.12117] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Long QT syndrome (LQTS) is an inherited disorder associated with life-threatening ventricular arrhythmias. An understanding of the relationship between the genotype and phenotype characteristics of LQTS can lead to improved risk stratification and management of this hereditary arrhythmogenic disorder. Risk stratification in LQTS relies on combined assessment of clinical, electrocardiographic, and mutations-specific factors. Studies have shown that there are genotype-specific risk factors for arrhythmic events including age, gender, resting heart rate, QT corrected for heart rate, prior syncope, the postpartum period, menopause, mutation location, type of mutation, the biophysical function of the mutation, and response to beta-blockers. Importantly, genotype-specific therapeutic options have been suggested. Lifestyle changes are recommended according to the prevalent trigger for cardiac events. Beta-blockers confer greater benefit among patients with LQT1 with the greatest benefit among those with cytoplasmic loops mutations; specific beta-blocker agents may provide greater protection than other agents in specific LQTS genotypes. Potassium supplementation and sex hormone-based therapy may protect patients with LQT2. Sodium channel blockers such as mexiletine, flecainide, and ranolazine could be treatment options in LQT3.
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Affiliation(s)
- Alon Barsheshet
- Cardiology Department, Rabin Medical Center, Petah Tikva, and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Cardiology Division, University of Rochester Medical Center, Rochester, NY
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Trafficking defects in PAS domain mutant Kv11.1 channels: roles of reduced domain stability and altered domain–domain interactions. Biochem J 2013; 454:69-77. [DOI: 10.1042/bj20130328] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Loss of Kv11.1 potassium channel function is the underlying cause of pathology in long-QT syndrome type 2, one of the commonest causes of sudden cardiac death in the young. Previous studies have identified the cytosolic PAS (Per/Arnt/Sim) domain as a hotspot for mutations that cause Kv11.1 trafficking defects. To investigate the underlying basis of this observation, we have quantified the effect of mutants on domain folding as well as interactions between the PAS domain and the remainder of the channel. Apart from R56Q, all mutants impaired the thermostability of the isolated PAS domain. Six mutants, located in the vicinity of a hydrophobic patch on the PAS domain surface, also affected binding of the isolated PAS domain to an N-terminal truncated hERG (human ether-a-go-go-related gene) channel. Conversely, four other surface mutants (C64Y, T65P, A78P and I96T) and one buried mutant (L86R) did not prevent the isolated PAS domain binding to the truncated channels. Our results highlight a critical role for interactions between the PAS domain and the remainder of the channel in the hERG assembly and that mutants that affect PAS domain interactions with the remainder of the channel have a more severe trafficking defect than that caused by domain unfolding alone.
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Hsiao PY, Tien HC, Lo CP, Juang JMJ, Wang YH, Sung RJ. Gene mutations in cardiac arrhythmias: a review of recent evidence in ion channelopathies. APPLICATION OF CLINICAL GENETICS 2013; 6:1-13. [PMID: 23837003 PMCID: PMC3699290 DOI: 10.2147/tacg.s29676] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Over the past 15 years, molecular genetic studies have linked gene mutations to many inherited arrhythmogenic disorders, in particular, “ion channelopathies”, in which mutations in genes encode functional units of ion channels and/or their transporter-associated proteins in patients without primary cardiac structural abnormalities. These disorders are exemplified by congenital long QT syndrome (LQTS), short QT syndrome, Brugada syndrome (BrS) and catecholaminergic polymorphic ventricular tachycardia (CPVT). Functional and pathophysiological studies have led to better understanding of the clinical spectrum, ion channel structures and cellular electrophysiology involving dynamics of intracellular calcium cycling in many subtypes of these disorders and more importantly, development of potentially more effective pharmacological agents and even curative gene therapy. In this review, we have summarized (1) the significance of unveiling mutations in genes encoding transporter-associated proteins as the cause of congenital LQTS, (2) the technique of catheter ablation applied at the right ventricular outflow tract may be curative for severely symptomatic BrS, (3) mutations with channel function modulated by protein Kinase A-dependent phosphorylation can be the culprit of CPVT mimicry in Andersen-Tawil syndrome (LQT7), (4) ablation of the ion channel anchoring protein may prevent arrhythmogenesis in Timothy syndrome (LQT8), (5) altered intracellular Ca2+ cycling can be the basis of effective targeted pharmacotherapy in CPVT, and (6) the technology of induced pluripotent stem cells is a promising diagnostic and research tool as it has become a new paradigm for pathophysiological study of patient- and disease-specific cells aimed at screening new drugs and eventual clinical application of gene therapy. Lastly, we have discussed (7) genotype-phenotype correlation in relation to risk stratification of patients with congenital LQTS in clinical practice.
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Affiliation(s)
- Pi-Yin Hsiao
- Institute of Life Sciences, National Central University, Taoyuan, Taiwan
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J Y, VH T, LF H, R L. Catheter ablation of ventricular fibrillation storm in a long QT syndrome genotype carrier with normal QT interval. Singapore Med J 2013. [DOI: 10.11622/smedj.2013015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Abstract
Although cardiac arrhythmia had long been considered a predominantly male syndrome, it is now clear that arrhythmia is also a primary cause of mortality in women. Notably, the manifestation of specific arrhythmia syndromes appears to be gender specific. In particular, female sex is an independent risk factor for development of torsade de pointes (TdP) arrhythmias not only in congenital long QT syndromes but also in acquired long QT syndromes which occur as adverse effects of existing drugs. Males, on the other hand, are more likely to develop Brugada syndrome. Recent clinical and experimental studies suggest that these differences may stem from intrinsic sex differences in cardiac tissue. These include fundamental electrical differences resulting from variable ion channel expression and diverse sex hormonal regulation via long-term genomic and acute nongenomic pathways, and sex differences in drug responses and metabolisms. Undoubtedly, determining the effect of gender on cardiac function will be difficult and require sophisticated methodologies. However, gender differences underlying predilection to distinct arrhythmia syndromes must be revealed so that new therapeutic strategies that take gender into account can be applied to at-risk patients.
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Affiliation(s)
- Junko Kurokawa
- Department of Bio-Informational Pharmacology, Tokyo Medical and Dental University, Tokyo, Japan.
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Balijepalli SY, Lim E, Concannon SP, Chew CL, Holzem KE, Tester DJ, Ackerman MJ, Delisle BP, Balijepalli RC, January CT. Mechanism of loss of Kv11.1 K+ current in mutant T421M-Kv11.1-expressing rat ventricular myocytes: interaction of trafficking and gating. Circulation 2012; 126:2809-18. [PMID: 23136156 DOI: 10.1161/circulationaha.112.118018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Type 2 long QT syndrome involves mutations in the human ether a-go-go-related gene (hERG or KCNH2). T421M, an S1 domain mutation in the Kv11.1 channel protein, was identified in a resuscitated patient. We assessed its biophysical, protein trafficking, and pharmacological mechanisms in adult rat ventricular myocytes. METHODS AND RESULTS Isolated adult rat ventricular myocytes were infected with wild-type (WT)-Kv11.1- and T421M-Kv11.1-expressing adenovirus and analyzed with the use of patch clamp, Western blot, and confocal imaging techniques. Expression of WT-Kv11.1 or T421M-Kv11.1 produced peak tail current (I(Kv11.1)) of 8.78±1.18 and 1.91±0.22 pA/pF, respectively. Loss of mutant I(Kv11.1) resulted from (1) a partially trafficking-deficient channel protein with reduced cell surface expression and (2) altered channel gating with a positive shift in the voltage dependence of activation and altered kinetics of activation and deactivation. Coexpression of WT+T421M-Kv11.1 resulted in heterotetrameric channels that remained partially trafficking deficient with only a minimal increase in peak I(Kv11.1) density, whereas the voltage dependence of channel gating became WT-like. In the adult rat ventricular myocyte model, both WT-Kv11.1 and T421M-Kv11.1 channels responded to β-adrenergic stimulation by increasing I(Kv11.1). CONCLUSIONS The T421M-Kv11.1 mutation caused a loss of I(Kv11.1) through interactions of abnormal protein trafficking and channel gating. Furthermore, for coexpressed WT+T421M-Kv11.1 channels, different dominant-negative interactions govern protein trafficking and ion channel gating, and these are likely to be reflected in the clinical phenotype. Our results also show that WT and mutant Kv11.1 channels responded to β-adrenergic stimulation.
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Perrin MJ, Gollob MH. Genetics of cardiac electrical disease. Can J Cardiol 2012; 29:89-99. [PMID: 23062665 DOI: 10.1016/j.cjca.2012.07.847] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 10/27/2022] Open
Abstract
Few tragedies compare to the sudden death of a family member. Sadly, this may represent the first sign of a familial vulnerability to such events. One common cause is an inherited cardiac arrhythmia syndrome. Sufferers are prone to premature sudden cardiac death due to altered ion channel function in the heart. Typical causes include Brugada syndrome, long QT syndrome, short QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and the newly recognized early repolarization syndrome. Our knowledge of the genetic underpinnings of each of these disorders has increased markedly in recent years. Genetic screening is now a routine part of clinical care and promises more accurate diagnosis and efficient family screening. This review summarizes the diagnosis and management of each of the listed syndromes in the context of currently available genetic testing.
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Affiliation(s)
- Mark J Perrin
- Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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