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Harvey A, Curnier D, Dodin P, Jacquemet V, Caru M. The Effects of Cycle Ergometer Versus Treadmill Exercise Stress Testing on QTc Interval Prolongation in Patients With Long QT Syndrome: A Systematic Review and Meta-analysis. Clin J Sport Med 2024; 34:474-502. [PMID: 39012267 DOI: 10.1097/jsm.0000000000001256] [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: 04/14/2023] [Accepted: 01/16/2024] [Indexed: 07/17/2024]
Abstract
OBJECTIVE The safest and most effective exercise stress tests (EST) modalities for long QT syndrome (LQTS) are currently unknown. The main objective was to explore the effects of EST on the corrected QT interval (QTc) in patients with LQTS, and to compare the effects of different EST modalities (cycle ergometer vs treadmill). DATA SOURCES Systematic searches were performed in September 2022 in accordance with the PRISMA statement through PubMed, Medline, EBM Reviews, Embase, and Web of Science. MAIN RESULTS A total of 1728 patients with LQTS, whether congenital or acquired, without any age restrictions (pediatric age ≤18 years and adult age >19 years), and 2437 control subjects were included in the 49 studies. The QT interval data were available for 15 studies. Our analyses showed that the QT interval prolonged in a similar manner using either a cycle ergometer or a treadmill (standardized mean difference [SMD] = 1.89 [95% CI, 1.07-2.71] vs SMD = 1.46 [95% CI, 0.78-2.14], respectively). Therefore, it seems that either modality may be used to evaluate patients with LQTS. CONCLUSIONS The methodology for the measurement of the QT interval was very heterogeneous between studies, which inevitably influenced the quality of the analyses. Hence, researchers should proceed with caution when exploring and interpreting data in the field of exercise and LQTS.
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Affiliation(s)
- Audrey Harvey
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Canada
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
| | - Daniel Curnier
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Canada
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
| | - Philippe Dodin
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
| | - Vincent Jacquemet
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada ; and
| | - Maxime Caru
- Department of Pediatrics and Department of Public Health Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
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2
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Dahlberg P, Axelsson KJ, Rydberg A, Lundahl G, Gransberg L, Bergfeldt L. Spatiotemporal repolarization dispersion before and after exercise in patients with long QT syndrome type 1 versus controls: probing into the arrhythmia substrate. Am J Physiol Heart Circ Physiol 2023; 325:H1279-H1289. [PMID: 37773058 DOI: 10.1152/ajpheart.00335.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 09/30/2023]
Abstract
Congenital long QT syndrome (LQTS) carries an increased risk for syncope and sudden death. QT prolongation promotes ventricular extrasystoles, which, in the presence of an arrhythmia substrate, might trigger ventricular tachycardia degenerating into fibrillation. Increased electrical heterogeneity (dispersion) is the suggested arrhythmia substrate in LQTS. In the most common subtype LQT1, physical exercise predisposes for arrhythmia and spatiotemporal dispersion was therefore studied in this context. Thirty-seven patients (57% on β-blockers) and 37 healthy controls (mean age, 31 vs. 35; range, 6-68 vs. 6-72 yr) performed an exercise test. Frank vectorcardiography was used to assess spatiotemporal dispersion as Tampl, Tarea, the ventricular gradient (VG), and the Tpeak-end interval from 10-s signal averages before and 7 ± 2 min after exercise; during exercise too much signal disturbance excluded analysis. Baseline and maximum heart rates as well as estimated exercise intensity were similar, but heart rate recovery was slower in patients. At baseline, QT and heart rate-corrected QT (QTcB) were significantly longer in patients (as expected), whereas dispersion parameters were numerically larger in controls. After exercise, QTpeakcB and Tpeak-endcB increased significantly more in patients (18 ± 23 vs. 7 ± 10 ms and 12 ± 17 vs. 2 ± 6 ms; P < 0.001 and P < 0.01). There was, however, no difference in the change in Tampl, Tarea, and VG between groups. In conclusion, although temporal dispersion of repolarization increased significantly more after exercise in patients with LQT1, there were no signs of exercise-induced increase in global dispersion of action potential duration and morphology. The arrhythmia substrate/mechanism in LQT1 warrants further study.NEW & NOTEWORTHY Physical activity increases the risk for life-threatening arrhythmias in LQTS type 1 (LQT1). The arrhythmia substrate is presumably altered electrical heterogeneity (a.k.a. dispersion). Spatiotemporal dispersion parameters were therefore compared before and after exercise in patients versus healthy controls using Frank vectorcardiography, a novelty. Physical exercise prolonged the time between the earliest and latest complete repolarization in patients versus controls, but did not increase parameters reflecting global dispersion of action potential duration and morphology, another novelty.
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Affiliation(s)
- Pia Dahlberg
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Region Vaestra Goetaland, Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Karl-Jonas Axelsson
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Region Vaestra Goetaland, Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Annika Rydberg
- Division of Pediatrics, Department of Clinical Sciences, Umeå University, Umeå, Sweden
| | - Gunilla Lundahl
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lennart Gransberg
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lennart Bergfeldt
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Region Vaestra Goetaland, Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden
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Abrahams T, Davies B, Laksman Z, Sy RW, Postema PG, Wilde AAM, Krahn AD, Han HC. Provocation testing in congenital long QT syndrome: A practical guide. Heart Rhythm 2023; 20:1570-1582. [PMID: 37481219 DOI: 10.1016/j.hrthm.2023.07.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 07/01/2023] [Accepted: 07/14/2023] [Indexed: 07/24/2023]
Abstract
Congenital long QT syndrome (LQTS) is a hereditary cardiac channelopathy with an estimated prevalence of 1 in 2500. A prolonged resting QT interval corrected for heart rate (QTc interval) remains a key diagnostic component; however, the QTc value may be normal in up to 40% of patients with genotype-positive LQTS and borderline in a further 30%. Provocation of QTc prolongation and T-wave changes may be pivotal to unmasking the diagnosis and useful in predicting genotype. LQTS provocation testing involves assessment of repolarization during and after exercise, in response to changes in heart rate or autonomic tone, with patients with LQTS exhibiting a maladaptive repolarization response. We review the utility and strengths and limitations of 4 forms of provocation testing-stand-up test, exercise stress test, epinephrine challenge, and mental stress test-in diagnosing LQTS and provide some practical guidance for performing provocation testing. Ultimately, exercise testing, when feasible, is the most useful form of provocation testing when considering diagnostic sensitivity and specificity.
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Affiliation(s)
- Timothy Abrahams
- Victorian Heart Institute & Monash Health Heart, Victorian Heart Hospital, Monash University, Melbourne, Victoria, Australia
| | - Brianna Davies
- Center for Cardiovascular Innovation, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Zachary Laksman
- Center for Cardiovascular Innovation, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Raymond W Sy
- Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Pieter G Postema
- Department of Cardiology, Amsterdam UMC location University of Amsterdam, Amsterdam, The Netherlands; Heart Failure & Arrhythmias, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart), Academic Medical Center, Amsterdam, The Netherlands
| | - Arthur A M Wilde
- Department of Cardiology, Amsterdam UMC location University of Amsterdam, Amsterdam, The Netherlands; Heart Failure & Arrhythmias, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart), Academic Medical Center, Amsterdam, The Netherlands
| | - Andrew D Krahn
- Center for Cardiovascular Innovation, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hui-Chen Han
- Victorian Heart Institute & Monash Health Heart, Victorian Heart Hospital, Monash University, Melbourne, Victoria, Australia.
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van Weperen VYH, Ripplinger CM, Vaseghi M. Autonomic control of ventricular function in health and disease: current state of the art. Clin Auton Res 2023; 33:491-517. [PMID: 37166736 PMCID: PMC10173946 DOI: 10.1007/s10286-023-00948-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 04/20/2023] [Indexed: 05/12/2023]
Abstract
PURPOSE Cardiac autonomic dysfunction is one of the main pillars of cardiovascular pathophysiology. The purpose of this review is to provide an overview of the current state of the art on the pathological remodeling that occurs within the autonomic nervous system with cardiac injury and available neuromodulatory therapies for autonomic dysfunction in heart failure. METHODS Data from peer-reviewed publications on autonomic function in health and after cardiac injury are reviewed. The role of and evidence behind various neuromodulatory therapies both in preclinical investigation and in-use in clinical practice are summarized. RESULTS A harmonic interplay between the heart and the autonomic nervous system exists at multiple levels of the neuraxis. This interplay becomes disrupted in the setting of cardiovascular disease, resulting in pathological changes at multiple levels, from subcellular cardiac signaling of neurotransmitters to extra-cardiac, extra-thoracic remodeling. The subsequent detrimental cycle of sympathovagal imbalance, characterized by sympathoexcitation and parasympathetic withdrawal, predisposes to ventricular arrhythmias, progression of heart failure, and cardiac mortality. Knowledge on the etiology and pathophysiology of this condition has increased exponentially over the past few decades, resulting in a number of different neuromodulatory approaches. However, significant knowledge gaps in both sympathetic and parasympathetic interactions and causal factors that mediate progressive sympathoexcitation and parasympathetic dysfunction remain. CONCLUSIONS Although our understanding of autonomic imbalance in cardiovascular diseases has significantly increased, specific, pivotal mediators of this imbalance and the recognition and implementation of available autonomic parameters and neuromodulatory therapies are still lagging.
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Affiliation(s)
- Valerie Y H van Weperen
- Division of Cardiology, Department of Medicine, UCLA Cardiac Arrythmia Center, University of California, 100 Medical Plaza, Suite 660, Los Angeles, CA, 90095, USA
| | | | - Marmar Vaseghi
- Division of Cardiology, Department of Medicine, UCLA Cardiac Arrythmia Center, University of California, 100 Medical Plaza, Suite 660, Los Angeles, CA, 90095, USA.
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Cui S, Hayashi K, Kobayashi I, Hosomichi K, Nomura A, Teramoto R, Usuda K, Okada H, Deng Y, Kobayashi-Sun J, Nishikawa T, Furusho H, Saito T, Hirase H, Ohta K, Fujimoto M, Horita Y, Kusayama T, Tsuda T, Tada H, Kato T, Usui S, Sakata K, Fujino N, Tajima A, Yamagishi M, Takamura M. The utility of zebrafish cardiac arrhythmia model to predict the pathogenicity of KCNQ1 variants. J Mol Cell Cardiol 2023; 177:50-61. [PMID: 36898499 DOI: 10.1016/j.yjmcc.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/11/2023]
Abstract
Genetic testing for inherited arrhythmias and discriminating pathogenic or benign variants from variants of unknown significance (VUS) is essential for gene-based medicine. KCNQ1 is a causative gene of type 1 long QT syndrome (LQTS), and approximately 30% of the variants found in type 1 LQTS are classified as VUS. We studied the role of zebrafish cardiac arrhythmia model in determining the clinical significance of KCNQ1 variants. We generated homozygous kcnq1 deletion zebrafish (kcnq1del/del) using the CRISPR/Cas9 and expressed human Kv7.1/MinK channels in kcnq1del/del embryos. We dissected the hearts from the thorax at 48 h post-fertilization and measured the transmembrane potential of the ventricle in the zebrafish heart. Action potential duration was calculated as the time interval between peak maximum upstroke velocity and 90% repolarization (APD90). The APD90 of kcnq1del/del embryos was 280 ± 47 ms, which was significantly shortened by injecting KCNQ1 wild-type (WT) cRNA and KCNE1 cRNA (168 ± 26 ms, P < 0.01 vs. kcnq1del/del). A study of two pathogenic variants (S277L and T587M) and one VUS (R451Q) associated with clinically definite LQTS showed that the APD90 of kcnq1del/del embryos with these mutant Kv7.1/MinK channels was significantly longer than that of Kv7.1 WT/MinK channels. Given the functional results of the zebrafish model, R451Q could be reevaluated physiologically from VUS to likely pathogenic. In conclusion, functional analysis using in vivo zebrafish cardiac arrhythmia model can be useful for determining the pathogenicity of loss-of-function variants in patients with LQTS.
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Affiliation(s)
- Shihe Cui
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Kenshi Hayashi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan; School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
| | - Isao Kobayashi
- Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Kazuyoshi Hosomichi
- Laboratory of Computational Genomics, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Akihiro Nomura
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Ryota Teramoto
- Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Keisuke Usuda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Hirofumi Okada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Yaowen Deng
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Jingjing Kobayashi-Sun
- Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan; Department of Clinical Engineering, Faculty of Health Sciences, Komatsu University, Komatsu, Japan
| | - Tetsuo Nishikawa
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Hiroshi Furusho
- Department of Cardiology, Ishikawa Prefectural Central Hospital, Kanazawa, Japan
| | - Takekatsu Saito
- Department of Pediatrics, Minamigaoka Hospital, Kanazawa, Japan
| | - Hiroaki Hirase
- Department of Cardiology, Takaoka Minami Heart Center, Takaoka, Japan
| | - Kunio Ohta
- Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical, and Health Sciences, Kanazawa University, Kanazawa, Japan; Medical Education Research Center, Graduate School of Medical Sciences, Kanazawa University, Japan
| | - Manabu Fujimoto
- Department of Cardiology, Kouseiren Takaoka Hospital, Takaoka, Japan
| | - Yuki Horita
- Department of Cardiology, Kanazawa Cardiovascular Hospital, Kanazawa, Japan
| | - Takashi Kusayama
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Toyonobu Tsuda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Hayato Tada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Takeshi Kato
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Soichiro Usui
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Kenji Sakata
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Noboru Fujino
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan; School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Atsushi Tajima
- Department of Bioinformatics and Genomics, Graduate School of Advanced Preventive Medical Sciences, Kanazawa University, Kanazawa, Japan
| | | | - Masayuki Takamura
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
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Rieder M, Kreifels P, Stuplich J, Ziupa D, Servatius H, Nicolai L, Castiglione A, Zweier C, Asatryan B, Odening KE. Genotype-Specific ECG-Based Risk Stratification Approaches in Patients With Long-QT Syndrome. Front Cardiovasc Med 2022; 9:916036. [PMID: 35911527 PMCID: PMC9329832 DOI: 10.3389/fcvm.2022.916036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Background Congenital long-QT syndrome (LQTS) is a major cause of sudden cardiac death (SCD) in young individuals, calling for sophisticated risk assessment. Risk stratification, however, is challenging as the individual arrhythmic risk varies pronouncedly, even in individuals carrying the same variant. Materials and Methods In this study, we aimed to assess the association of different electrical parameters with the genotype and the symptoms in patients with LQTS. In addition to the heart-rate corrected QT interval (QTc), markers for regional electrical heterogeneity, such as QT dispersion (QTmax-QTmin in all ECG leads) and delta Tpeak/end (Tpeak/end V5 – Tpeak/end V2), were assessed in the 12-lead ECG at rest and during exercise testing. Results QTc at rest was significantly longer in symptomatic than asymptomatic patients with LQT2 (493.4 ms ± 46.5 ms vs. 419.5 ms ± 28.6 ms, p = 0.004), but surprisingly not associated with symptoms in LQT1. In contrast, post-exercise QTc (minute 4 of recovery) was significantly longer in symptomatic than asymptomatic patients with LQT1 (486.5 ms ± 7.0 ms vs. 463.3 ms ± 16.3 ms, p = 0.04), while no such difference was observed in patients with LQT2. Enhanced delta Tpeak/end and QT dispersion were only associated with symptoms in LQT1 (delta Tpeak/end 19.0 ms ± 18.1 ms vs. −4.0 ms ± 4.4 ms, p = 0.02; QT-dispersion: 54.3 ms ± 10.2 ms vs. 31.4 ms ± 10.4 ms, p = 0.01), but not in LQT2. Delta Tpeak/end was particularly discriminative after exercise, where all symptomatic patients with LQT1 had positive and all asymptomatic LQT1 patients had negative values (11.8 ± 7.9 ms vs. −7.5 ± 1.7 ms, p = 0.003). Conclusion Different electrical parameters can distinguish between symptomatic and asymptomatic patients in different genetic forms of LQTS. While the classical “QTc at rest” was only associated with symptoms in LQT2, post-exercise QTc helped distinguish between symptomatic and asymptomatic patients with LQT1. Enhanced regional electrical heterogeneity was only associated with symptoms in LQT1, but not in LQT2. Our findings indicate that genotype-specific risk stratification approaches based on electrical parameters could help to optimize risk assessment in LQTS.
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Affiliation(s)
- Marina Rieder
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Paul Kreifels
- Department of Cardiology and Angiology I, Faculty of Medicine, University Heart Center Freiburg-Bad Krozingen, University of Freiburg, Freiburg, Germany
| | - Judith Stuplich
- Department of Cardiology and Angiology I, Faculty of Medicine, University Heart Center Freiburg-Bad Krozingen, University of Freiburg, Freiburg, Germany
| | - David Ziupa
- Department of Cardiology and Angiology I, Faculty of Medicine, University Heart Center Freiburg-Bad Krozingen, University of Freiburg, Freiburg, Germany
| | - Helge Servatius
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Luisa Nicolai
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Alessandro Castiglione
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Christiane Zweier
- Department of Human Genetics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Babken Asatryan
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Katja E Odening
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
- Department of Physiology, University of Bern, Bern, Switzerland
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Song Y, Guo T, Jiang Y, Zhu M, Wang H, Lu W, Jiang M, Qi M, Lan F, Cui M. KCNQ1-deficient and KCNQ1-mutant human embryonic stem cell-derived cardiomyocytes for modeling QT prolongation. Stem Cell Res Ther 2022; 13:287. [PMID: 35765105 PMCID: PMC9241307 DOI: 10.1186/s13287-022-02964-3] [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: 01/11/2022] [Accepted: 03/20/2022] [Indexed: 11/10/2022] Open
Abstract
Background The slowly activated delayed rectifier potassium current (IKs) mediated by the KCNQ1 gene is one of the main currents involved in repolarization. KCNQ1 mutation can result in long-QT syndrome type 1 (LQT1). IKs does not participate in repolarization in mice; thus, no good model is currently available for research on the mechanism of and drug screening for LQT1. In this study, we established a KCNQ1-deficient human cardiomyocyte (CM) model and performed a series of microelectrode array (MEA) detection experiments on KCNQ1-mutant CMs constructed in other studies to explore the pathogenic mechanism of KCNQ1 deletion and mutation and perform drug screening. Method KCNQ1 was knocked out in human embryonic stem cell (hESC) H9 line using the CRISPR/cas9 system. KCNQ1-deficient and KCNQ1-mutant hESCs were differentiated into CMs through a chemically defined differentiation protocol. Subsequently, high-throughput MEA analysis and drug intervention were performed to determine the electrophysiological characteristics of KCNQ1-deficient and KCNQ1-mutant CMs. Results During high-throughput MEA analysis, the electric field potential and action potential durations in KCNQ1-deficient CMs were significantly longer than those in wild-type CMs. KCNQ1-deficient CMs also showed an irregular rhythm. Furthermore, KCNQ1-deficient and KCNQ1-mutant CMs showed different responses to different drug treatments, which reflected the differences in their pathogenic mechanisms. Conclusion We established a human CM model with KCNQ1 deficiency showing a prolonged QT interval and an irregular heart rhythm. Further, we used various drugs to treat KCNQ1-deficient and KCNQ1-mutant CMs, and the three models showed different responses to these drugs. These models can be used as important tools for studying the different pathogenic mechanisms of KCNQ1 mutation and the relationship between the genotype and phenotype of KCNQ1, thereby facilitating drug development. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-022-02964-3.
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Affiliation(s)
- Yuanxiu Song
- Department of Cardiology, Peking University Third Hospital, 49 Huayuan North Road, Haidian District, Beijing, 100191, China
| | - Tianwei Guo
- Beijing Lab for Cardiovascular Precision Medicine, Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Youxu Jiang
- Department of Cardiology, The Second Affiliated Hospital of Zhengzhou University, Jingba Road, Zhengzhou, 450053, China
| | - Min Zhu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Hongyue Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Wenjing Lu
- Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, 518057, China
| | - Mengqi Jiang
- Department of Cell Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Man Qi
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Feng Lan
- Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, 518057, China.
| | - Ming Cui
- Department of Cardiology, Peking University Third Hospital, 49 Huayuan North Road, Haidian District, Beijing, 100191, China.
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8
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Harvey A, Curnier D, Dodin P, Abadir S, Jacquemet V, Caru M. OUP accepted manuscript. Eur J Prev Cardiol 2022; 29:1633-1677. [PMID: 35537006 DOI: 10.1093/eurjpc/zwac081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022]
Abstract
Current exercise recommendations make it difficult for long QT syndrome (LQTS) patients to adopt a physically active and/or athletic lifestyle. The purpose of this review is to summarize the current evidence, identify knowledge gaps, and discuss research perspectives in the field of exercise and LQTS. The first aim is to document the influence of exercise training, exercise stress, and postural change interventions on ventricular repolarization in LQTS patients, while the second aim is to describe electrophysiological measurements used to study the above. Studies examining the effects of exercise on congenital or acquired LQTS in human subjects of all ages were included. Systematic searches were performed on 1 October 2021, through PubMed (NLM), Ovid Medline, Ovid All EBM Reviews, Ovid Embase, and ISI Web of Science, and limited to articles written in English or French. A total of 1986 LQTS patients and 2560 controls were included in the 49 studies. Studies were mainly case-control studies (n = 41) and examined exercise stress and/or postural change interventions (n = 48). One study used a 3-month exercise training program. Results suggest that LQTS patients have subtype-specific repolarization responses to sympathetic stress. Measurement methods and quality were found to be very heterogeneous, which makes inter-study comparisons difficult. In the absence of randomized controlled trials, the current recommendations may have long-term risks for LQTS patients who are discouraged from performing physical activity, rendering its associated health benefits out of range. Future research should focus on discovering the most appropriate levels of exercise training that promote ventricular repolarization normalization in LQTS.
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Affiliation(s)
- Audrey Harvey
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Canada
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
| | - Daniel Curnier
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Canada
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
| | - Philippe Dodin
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
| | - Sylvia Abadir
- Department of Pediatric Cardiology, Sainte-Justine University Health Center, Montreal, Canada
| | - Vincent Jacquemet
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada
| | - Maxime Caru
- Sainte-Justine University Health Center, Research Center, Montreal, Canada
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA, USA
- Department of Public Health Sciences, Pennsylvania State University College of Medicine, Hershey, PA, USA
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9
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Maury P, Delasnerie H, Beneyto M, Rollin A. Autonomic cardiac innervation: impact on the evolution of arrhythmias in inherited cardiac arrhythmia syndromes. Herzschrittmacherther Elektrophysiol 2021; 32:308-314. [PMID: 34185133 DOI: 10.1007/s00399-021-00774-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 05/17/2021] [Indexed: 11/28/2022]
Abstract
The autonomic nervous system (ANS) is an essential component of arrhythmogenicity, especially in the absence of structural heart disease and channelopathy. In this article, the authors review the role and characteristics of ANS in various channelopathies. Some of these, such as most long QT syndromes and catecholaminergic polymorphic ventricular tachycardia, are highly dependent on sympathetic activation, while parasympathetic tone is an important factor for arrhythmias in other channelopathies such as Brugada syndrome or early repolarisation syndrome. Recent advances highlighting the subtle role of ANS in channelopathies are presented here, demonstrating that all is far from being so simple and straightforward and revealing some paradoxical behaviours of channelopathies in relation to discrete ANS imbalance.
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Affiliation(s)
- Philippe Maury
- Department of Cardiology, University Hospital Rangueil, Toulouse, France. .,I2MC, INSERM UMR 1297, Toulouse, France.
| | - Hubert Delasnerie
- Department of Cardiology, University Hospital Rangueil, Toulouse, France
| | - Maxime Beneyto
- Department of Cardiology, University Hospital Rangueil, Toulouse, France
| | - Anne Rollin
- Department of Cardiology, University Hospital Rangueil, Toulouse, France
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10
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Lankaputhra M, Voskoboinik A. Congenital Long QT Syndrome: A Clinician's Guide. Intern Med J 2021; 51:1999-2011. [PMID: 34151491 DOI: 10.1111/imj.15437] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/31/2021] [Accepted: 06/15/2021] [Indexed: 11/29/2022]
Abstract
Congenital long QT syndrome (LQTS) is a familial cardiac ion channelopathy first described over sixty years ago. It is characterised by prolonged ventricular repolarization (long QT on ECG), ventricular arrhythmias and associated syncope or sudden cardiac death. As the most closely studied cardiac channelopathy, over the decades we have gained a deep appreciation of the complex genetic model of LQTS. Variability in genetic expression and incomplete penetrance leads to a heterogenous phenotype that can be challenging to clinically classify. In recent times, progress has been made in diagnostic method, risk stratification and treatment options. This review has been written as a guide for the general cardiologist to understand the basic pathophysiology, diagnosis, and management priorities for the most encountered LQTS subtypes: LQT1, LQT2 and LQT3. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Aleksandr Voskoboinik
- Division of Cardiology, Alfred Health, Melbourne, Australia.,Division of Cardiology Western Health, Monash University & Baker Heart & Diabetes Institute, Melbourne, Australia
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11
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Takahashi K, Shimizu W, Makita N, Nakayashiro M. Dynamic QT response to cold-water face immersion in long-QT syndrome type 3. Pediatr Int 2020; 62:899-906. [PMID: 32449227 PMCID: PMC7496693 DOI: 10.1111/ped.14319] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 05/03/2020] [Accepted: 05/18/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Abnormal dynamics of QT intervals in response to sympathetic nervous system stimulation are used to diagnose long-QT syndrome (LQTS). We hypothesized that parasympathetic stimulation with cold-water face immersion following exercise would influence QT dynamics in patients with LQTS type 3 (LQT3). METHODS Study participants (n = 42; mean age = 11.2 years) comprised 20 genotyped LQTS children and 22 healthy children. The LQTS group was divided into LQT3 (n = 12) and non-LQT3 (n = 8) subgroups. Provocative testing for assessing QT dynamics comprised a treadmill exercise followed by cold-water face immersion. The QT intervals were automatically measured at rest and during exercise, recovery, and cold-water face immersion. The QT/heart rate (HR) relationship was visualized by plotting beat-to-beat confluence of the data. RESULTS The QT/HR slopes, determined by linear regression analysis, were steeper in the LQTS group than in the control group during exercise and immersion tests: -2.16 ± 0.63 versus -1.21 ± 0.28, P < 0.0001, and -2.02 ± 0.76 vs -0.75 ± 0.24, P < 0.0001, respectively. The LQT3 patients had steeper slopes in the immersion test than did non-LQT3 and control individuals: -2.42 ± 0.52 vs -1.40 ± 0.65, P < 0.0001, and vs -0.75 ± 0.24, P < 0.0001. CONCLUSIONS The QT dynamics of LQT3 patients differ from those of other LQTS subtypes during the post-exercise cold-water face immersion test in this study. Abnormal QT dynamics during the parasympathetic provocative test are concordant with the fact that cardiac events occur when HRs are lower or during sleep in LQT3 patients.
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Affiliation(s)
- Kazuhiro Takahashi
- Department of Pediatric CardiologyOkinawa Nanbu and Children’s Medical CenterOkinawaJapan
| | | | - Naomasa Makita
- National Cerebral and Cardiovascular CenterResearch InstituteOsakaJapan
| | - Mami Nakayashiro
- Department of Pediatric CardiologyOkinawa Nanbu and Children’s Medical CenterOkinawaJapan
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12
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Saadeh K, Shivkumar K, Jeevaratnam K. Targeting the β-adrenergic receptor in the clinical management of congenital long QT syndrome. Ann N Y Acad Sci 2020; 1474:27-46. [PMID: 32901453 DOI: 10.1111/nyas.14425] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/10/2020] [Accepted: 06/09/2020] [Indexed: 01/01/2023]
Abstract
The long QT syndrome (LQTS) is largely treated pharmacologically with β-blockers, despite the role of sympathetic activity in LQTS being poorly understood. Using the trigger-substrate model of cardiac arrhythmias in this review, we amalgamate current experimental and clinical data from both animal and human studies to explain the mechanism of adrenergic stimulation and blockade on LQT arrhythmic risk and hence assess the efficacy of β-adrenoceptor blockade in the management of LQTS. In LQTS1 and LQTS2, sympathetic stimulation increases arrhythmic risk by enhancing early afterdepolarizations and transmural dispersion of repolarization. β-Blockers successfully reduce cardiac events by reducing these triggers and substrates; however, these effects are less marked in LQTS2 compared with LQTS1. In LQTS3, clinical and experimental investigations of the effects of sympathetic stimulation and β-blocker use have produced contradictory findings, resulting in significant clinical uncertainty. We offer explanations for these contradicting results relating to study sample size, the dose of the β-blocker administered associated with its off-target Na+ channel effects, as well as the type of β-blocker used. We conclude that the antiarrhythmic efficacy of β-blockers is a genotype-specific phenomenon, and hence the use of β-blockers in clinical practice should be genotype dependent.
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Affiliation(s)
- Khalil Saadeh
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Centre, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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13
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An actionable KCNH2 Long QT Syndrome variant detected by sequence and haplotype analysis in a population research cohort. Sci Rep 2019; 9:10964. [PMID: 31358886 PMCID: PMC6662790 DOI: 10.1038/s41598-019-47436-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/17/2019] [Indexed: 12/12/2022] Open
Abstract
The Viking Health Study Shetland is a population-based research cohort of 2,122 volunteer participants with ancestry from the Shetland Isles in northern Scotland. The high kinship and detailed phenotype data support a range of approaches for associating rare genetic variants, enriched in this isolate population, with quantitative traits and diseases. As an exemplar, the c.1750G > A; p.Gly584Ser variant within the coding sequence of the KCNH2 gene implicated in Long QT Syndrome (LQTS), which occurred once in 500 whole genome sequences from this population, was investigated. Targeted sequencing of the KCNH2 gene in family members of the initial participant confirmed the presence of the sequence variant and identified two further members of the same family pedigree who shared the variant. Investigation of these three related participants for whom single nucleotide polymorphism (SNP) array genotypes were available allowed a unique shared haplotype of 1.22 Mb to be defined around this locus. Searching across the full cohort for this haplotype uncovered two additional apparently unrelated individuals with no known genealogical connection to the original kindred. All five participants with the defined haplotype were shown to share the rare variant by targeted Sanger sequencing. If this result were verified in a healthcare setting, it would be considered clinically actionable, and has been actioned in relatives ascertained independently through clinical presentation. The General Practitioners of four study participants with the rare variant were alerted to the research findings by letters outlining the phenotype (prolonged electrocardiographic QTc interval). A lack of detectable haplotype sharing between c.1750G > A; p.Gly584Ser chromosomes from previously reported individuals from Finland and those in this study from Shetland suggests that this mutation has arisen more than once in human history. This study showcases the potential value of isolate population-based research resources for genomic medicine. It also illustrates some challenges around communication of actionable findings in research participants in this context.
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14
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Gardner RJM, Crozier IG, Binfield AL, Love DR, Lehnert K, Gibson K, Lintott CJ, Snell RG, Jacobsen JC, Jones PP, Waddell-Smith KE, Kennedy MA, Skinner JR. Penetrance and expressivity of the R858H CACNA1C variant in a five-generation pedigree segregating an arrhythmogenic channelopathy. Mol Genet Genomic Med 2018; 7:e00476. [PMID: 30345660 PMCID: PMC6382452 DOI: 10.1002/mgg3.476] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/22/2018] [Accepted: 08/23/2018] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Isolated cardiac arrhythmia due to a variant in CACNA1C is of recent knowledge. Most reports have been of singleton cases or of quite small families, and estimates of penetrance and expressivity have been difficult to obtain. We here describe a large pedigree, from which such estimates have been calculated. METHODS We studied a five-generation family, in which a CACNA1C variant c.2573G>A p.Arg858His co-segregates with syncope and cardiac arrest, documenting electrocardiographic data and cardiac symptomatology. The reported patients/families from the literature with CACNA1C gene variants were reviewed, and genotype-phenotype correlations are drawn. RESULTS The range of phenotype in the studied family is wide, from no apparent effect, through an asymptomatic QT interval prolongation on electrocardiography, to episodes of presyncope and syncope, ventricular fibrillation, and sudden death. QT prolongation showed inconsistent correlation with functional cardiology. Based upon analysis of 28 heterozygous family members, estimates of penetrance and expressivity are derived. CONCLUSIONS These estimates of penetrance and expressivity, for this specific variant, may be useful in clinical practice. Review of the literature indicates that individual CACNA1C variants have their own particular genotype-phenotype correlations. We suggest that, at least in respect of the particular variant reported here, "arrhythmogenic channelopathy" may be a more fitting nomenclature than long QT syndrome.
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Affiliation(s)
- R J McKinlay Gardner
- Cardiac Inherited Disease Group, Auckland, New Zealand.,Genetic Health Service New Zealand (South Island Hub), Christchurch Hospital, Christchurch, New Zealand.,Clinical Genetics Group, Department of Women's and Children's Health, University of Otago, Dunedin, New Zealand
| | - Ian G Crozier
- Cardiac Inherited Disease Group, Auckland, New Zealand.,Department of Cardiology, Christchurch Hospital, Christchurch, New Zealand
| | - Alex L Binfield
- Cardiac Inherited Disease Group, Auckland, New Zealand.,Department of Paediatrics, Christchurch Hospital, Christchurch, New Zealand.,Department of Paediatrics, University of Otago, Christchurch, New Zealand
| | - Donald R Love
- Cardiac Inherited Disease Group, Auckland, New Zealand.,LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Klaus Lehnert
- Cardiac Inherited Disease Group, Auckland, New Zealand.,School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Kate Gibson
- Cardiac Inherited Disease Group, Auckland, New Zealand.,Genetic Health Service New Zealand (South Island Hub), Christchurch Hospital, Christchurch, New Zealand
| | - Caroline J Lintott
- Cardiac Inherited Disease Group, Auckland, New Zealand.,Genetic Health Service New Zealand (South Island Hub), Christchurch Hospital, Christchurch, New Zealand
| | - Russell G Snell
- Cardiac Inherited Disease Group, Auckland, New Zealand.,School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Jessie C Jacobsen
- Cardiac Inherited Disease Group, Auckland, New Zealand.,School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Peter P Jones
- Cardiac Inherited Disease Group, Auckland, New Zealand.,Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand
| | - Kathryn E Waddell-Smith
- Cardiac Inherited Disease Group, Auckland, New Zealand.,Department of Cardiology, Auckland City Hospital, Auckland, New Zealand
| | - Martin A Kennedy
- Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
| | - Jonathan R Skinner
- Cardiac Inherited Disease Group, Auckland, New Zealand.,Department of Cardiology, Auckland City Hospital, Auckland, New Zealand
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15
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Postmortem Analysis of 4 Mutation Hotspots of KCNQ1, KCNH2, and SCN5A Genes in Sudden Unexplained Death in Southwest of China. ACTA ACUST UNITED AC 2018; 39:218-222. [DOI: 10.1097/paf.0000000000000411] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Wilders R, Verkerk AO. Long QT Syndrome and Sinus Bradycardia-A Mini Review. Front Cardiovasc Med 2018; 5:106. [PMID: 30123799 PMCID: PMC6085426 DOI: 10.3389/fcvm.2018.00106] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 07/16/2018] [Indexed: 12/16/2022] Open
Abstract
Congenital long-QT syndrome (LQTS) is an inherited cardiac disorder characterized by the prolongation of ventricular repolarization, susceptibility to Torsades de Pointes (TdP), and a risk for sudden death. Various types of congenital LQTS exist, all due to specific defects in ion channel-related genes. Interestingly, almost all of the ion channels affected by the various types of LQTS gene mutations are also expressed in the human sinoatrial node (SAN). It is therefore not surprising that LQTS is frequently associated with a change in basal heart rate (HR). However, current data on how the LQTS-associated ion channel defects result in impaired human SAN pacemaker activity are limited. In this mini-review, we provide an overview of known LQTS mutations with effects on HR and the underlying changes in expression and kinetics of ion channels. Sinus bradycardia has been reported in relation to a large number of LQTS mutations. However, the occurrence of both QT prolongation and sinus bradycardia on a family basis is almost completely limited to LQTS types 3 and 4 (LQT3 and Ankyrin-B syndrome, respectively). Furthermore, a clear causative role of this sinus bradycardia in cardiac events seems reserved to mutations underlying LQT3.
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Affiliation(s)
- Ronald Wilders
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | - Arie O Verkerk
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam University Medical Centers, Amsterdam, Netherlands
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17
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Koponen M, Havulinna AS, Marjamaa A, Tuiskula AM, Salomaa V, Laitinen-Forsblom PJ, Piippo K, Toivonen L, Kontula K, Viitasalo M, Swan H. Clinical and molecular genetic risk determinants in adult long QT syndrome type 1 and 2 patients : Koponen et al. Follow-up of adult LQTS patients. BMC MEDICAL GENETICS 2018; 19:56. [PMID: 29622001 PMCID: PMC5887247 DOI: 10.1186/s12881-018-0574-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 03/23/2018] [Indexed: 11/10/2022]
Abstract
Background Long QT syndrome (LQTS) is an inherited cardiac disorder predisposing to sudden cardiac death (SCD). We studied factors affecting the clinical course of genetically confirmed patients, in particular those not receiving β-blocker treatment. In addition, an attempt was made to associate risk of events to specific types of KCNQ1 and KCNH2 mutations. Methods A follow-up study covering a mean of 18.6 ± 6.1 years was conducted in 867 genetically confirmed LQT1 and LQT2 patients and 654 non-carrier relatives aged 18–40 years. Cox regression models were used to evaluate the contribution of clinical and genetic risk factors to cardiac events. Results In mutation carriers, risk factors for cardiac events before initiation of β-blocker included LQT2 genotype (hazard ratio [HR] = 2.1, p = 0.002), female gender (HR = 3.2, p < 0.001), a cardiac event before the age of 18 years (HR = 5.9, p < 0.001), and QTc ≥500 ms (vs < 470 ms, HR = 2.7, p = 0.001). LQT1 patients carrying the KCNQ1 D317N mutation were at higher risk (HR = 3.0–3.9, p < 0.001–0.03) compared to G589D, c.1129-2A > G and other KCNQ1 mutation carriers after adjusting for gender, QTc duration, and cardiac events before age 18. KCNH2 c.453delC, L552S and R176W mutations associated with lower risk (HR = 0.11–0.23, p < 0.001) than other KCNH2 mutations. Conclusions LQT2 (compared to LQT1), female gender, a cardiac event before age 18, and long QT interval increased the risk of cardiac events in LQTS patients aged 18 to 40 years. The nature of the underlying mutation may be associated with risk variation in both LQT1 and LQT2. The identification of high-risk and low-risk mutations may enhance risk stratification. Electronic supplementary material The online version of this article (10.1186/s12881-018-0574-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mikael Koponen
- Heart and Lung Center, Helsinki University Central Hospital, Helsinki, Finland.
| | - Aki S Havulinna
- Department of Health, National Institute for Health and Welfare, Helsinki, Finland
| | - Annukka Marjamaa
- Heart and Lung Center, Helsinki University Central Hospital, Helsinki, Finland
| | - Annukka M Tuiskula
- Department of Medicine, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Veikko Salomaa
- Department of Health, National Institute for Health and Welfare, Helsinki, Finland
| | | | - Kirsi Piippo
- Department of Genetics, United Medix Laboratories Ltd, Helsinki, Finland
| | - Lauri Toivonen
- Heart and Lung Center, Helsinki University Central Hospital, Helsinki, Finland
| | - Kimmo Kontula
- Department of Medicine, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Matti Viitasalo
- Heart and Lung Center, Helsinki University Central Hospital, Helsinki, Finland
| | - Heikki Swan
- Heart and Lung Center, Helsinki University Central Hospital, Helsinki, Finland
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18
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Perioperative management of patients with congenital or acquired disorders of the QT interval. Br J Anaesth 2018; 120:629-644. [DOI: 10.1016/j.bja.2017.12.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/16/2017] [Accepted: 01/14/2018] [Indexed: 12/19/2022] Open
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19
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Mascia G, Arbelo E, Solimene F, Giaccardi M, Brugada R, Brugada J. The long-QT syndrome and exercise practice: The never-ending debate. J Cardiovasc Electrophysiol 2018; 29:489-496. [DOI: 10.1111/jce.13410] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/14/2017] [Accepted: 12/18/2017] [Indexed: 01/02/2023]
Affiliation(s)
- Giuseppe Mascia
- Electrophysiology Unit; Clinica Montevergine; Mercogliano Italy
| | - Elena Arbelo
- Arrhythmia Section, Cardiology Department, Hospital Clínic, IDIBAPS; University of Barcelona; Barcelona Spain
| | | | - Marzia Giaccardi
- Cardiology and Electrophysiology Unit, Department of Internal Medicine; Santa Maria Nuova Hospital; Florence Italy
| | - Ramon Brugada
- Cardiovascular Genetics Center, Institut d'Investigació Biomèdica Girona (IDIBGI); University of Girona; Girona Spain
| | - Josep Brugada
- Arrhythmia Section, Cardiology Department, Hospital Clínic, IDIBAPS; University of Barcelona; Barcelona Spain
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20
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Goldstein SA, Ward CC, Al-Khatib SM. The Use of Implantable Cardioverter-defibrillators in the Prevention of Sudden Cardiac Death: A Focus on Congenital Heart Disease and Inherited Arrhythmia Syndromes. J Innov Card Rhythm Manag 2018; 9:2996-3005. [PMID: 32494470 PMCID: PMC7252881 DOI: 10.19102/icrm.2018.090103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 08/23/2017] [Indexed: 12/18/2022] Open
Abstract
Some congenital heart diseases (CHDs) and inherited arrhythmia syndromes are associated with an increased risk of sudden cardiac death (SCD). Appropriate selection criteria for implantable cardioverter-defibrillator (ICD) implantation in these patients are poorly defined due to a paucity of data available from randomized clinical trials, leading to current guidelines relying more on non-randomized studies and expert opinions to make their recommendations. This review describes available evidence-based risk stratification methods for identifying patients at risk for SCD, as well as current guideline-driven management strategies for the use of ICDs in patients with CHD and inherited arrhythmia syndromes.
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Affiliation(s)
| | - Cary C Ward
- Division of Cardiology, Duke University Hospital, Durham, NC, USA.,Duke Clinical Research Institute, Duke University Hospital, Durham, NC, USA
| | - Sana M Al-Khatib
- Division of Cardiology, Duke University Hospital, Durham, NC, USA.,Duke Clinical Research Institute, Duke University Hospital, Durham, NC, USA
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21
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Kwok SY, Pflaumer A, Pantaleo SJ, Date E, Jadhav M, Davis AM. Ten-year experience in atenolol use and exercise evaluation in children with genetically proven long QT syndrome. J Arrhythm 2017; 33:624-629. [PMID: 29255512 PMCID: PMC5728996 DOI: 10.1016/j.joa.2017.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 07/19/2017] [Accepted: 08/15/2017] [Indexed: 11/13/2022] Open
Abstract
Background Due to its availability, atenolol is the primary beta-blocker used in Australia for children with long QT syndrome. There is limited data on long-term follow-up of its use. Methods A single-tertiary-center, retrospective, observational study investigating all children and adolescents who had genetically proven long QT syndrome type 1 (LQT1) and type 2 (LQT2) was conducted. Their pretreatment exercise tests were evaluated for QTc intervals into the recovery phase of exercise. Results Eighty six patients were identified (LQT1, 67, and LQT2, 19) from 2004 to 2014. The majority (86%) of patients were initially referred for family screening. Atenolol was administered at a mean dose of 1.58 ± 0.51 mg/kg/day. During the median follow-up period of 4.29 years, only one proband developed ventricular arrhythmia whilst taking atenolol, No patient had cardiac arrest or aborted cardiac arrest. With respect to side effects of atenolol, only two patients had intolerable side effects necessitating changes of medication. Evaluation of exercise tests (pretreatment) demonstrated that corrected QT (QTc) intervals at 2–3 min into the recovery phase of exercise were significantly prolonged for LQT1 patients. LQT1 patients with transmembrane mutation had longer QTc intervals than their C-terminus mutation counterparts, reaching statistical significance at 3 min into the recovery phase of exercise. Conclusions Atenolol is an effective treatment for genetically proven LQT1 and LQT2 children and adolescents, with good tolerability. In LQT1 patients, QTc intervals at 2–3 min into the recovery phase of exercise were significantly prolonged, particularly in patients with transmembrane mutations.
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Key Words
- Atenolol
- Beta-blocker
- ECG, Electrocardiogram
- Exercise
- ICD, Implantable cardioverter-defibrillator
- LCSD, Left cardiac sympathetic denervation
- LQT1, Long QT syndrome type 1
- LQT2, Long QT syndrome type 2
- LQTS, Long QT syndrome
- Long QT syndrome
- Pediatrics
- QTc, Corrected QT
- SD, Standard deviation
- SFM, Screened family members
- TdP, Torsade de pointes
- min, Minutes
- s, Seconds
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Affiliation(s)
- Sit-Yee Kwok
- Department of Cardiology, Royal Children's Hospital, Melbourne, Australia
| | - Andreas Pflaumer
- Department of Cardiology, Royal Children's Hospital, Melbourne, Australia.,Murdoch Children's Research Institute, Parkville, VIC 3052, Australia.,Department of Paediatrics, Melbourne University, Australia
| | | | - Erin Date
- Department of Cardiology, Royal Children's Hospital, Melbourne, Australia
| | - Mangesh Jadhav
- Department of Cardiology, Royal Children's Hospital, Melbourne, Australia
| | - Andrew Mark Davis
- Department of Cardiology, Royal Children's Hospital, Melbourne, Australia.,Murdoch Children's Research Institute, Parkville, VIC 3052, Australia.,Department of Paediatrics, Melbourne University, Australia
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22
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Ionic mechanisms of the action of anaesthetics on sinoatrial node automaticity. Eur J Pharmacol 2017; 814:63-72. [DOI: 10.1016/j.ejphar.2017.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 07/06/2017] [Accepted: 08/07/2017] [Indexed: 12/11/2022]
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23
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Loss of type 9 adenylyl cyclase triggers reduced phosphorylation of Hsp20 and diastolic dysfunction. Sci Rep 2017; 7:5522. [PMID: 28717248 PMCID: PMC5514062 DOI: 10.1038/s41598-017-05816-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/05/2017] [Indexed: 01/16/2023] Open
Abstract
Adenylyl cyclase type 9 (AC9) is found tightly associated with the scaffolding protein Yotiao and the IKs ion channel in heart. But apart from potential IKs regulation, physiological roles for AC9 are unknown. We show that loss of AC9 in mice reduces less than 3% of total AC activity in heart but eliminates Yotiao-associated AC activity. AC9−/− mice exhibit no structural abnormalities but show a significant bradycardia, consistent with AC9 expression in sinoatrial node. Global changes in PKA phosphorylation patterns are not altered in AC9−/− heart, however, basal phosphorylation of heat shock protein 20 (Hsp20) is significantly decreased. Hsp20 binds AC9 in a Yotiao-independent manner and deletion of AC9 decreases Hsp20-associated AC activity in heart. In addition, expression of catalytically inactive AC9 in neonatal cardiomyocytes decreases isoproterenol-stimulated Hsp20 phosphorylation, consistent with an AC9-Hsp20 complex. Phosphorylation of Hsp20 occurs largely in ventricles and is vital for the cardioprotective effects of Hsp20. Decreased Hsp20 phosphorylation suggests a potential baseline ventricular defect for AC9−/−. Doppler echocardiography of AC9−/− displays a decrease in the early ventricular filling velocity and ventricular filling ratio (E/A), indicative of grade 1 diastolic dysfunction and emphasizing the importance of local cAMP production in the context of macromolecular complexes.
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24
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Gravel H, Curnier D, Dahdah N, Jacquemet V. Categorization and theoretical comparison of quantitative methods for assessing QT/RR hysteresis. Ann Noninvasive Electrocardiol 2017; 22. [PMID: 28510313 DOI: 10.1111/anec.12463] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 03/27/2017] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND In the human electrocardiogram, there is a lag of adaptation of the QT interval to heart rate changes, usually termed QT/RR hysteresis (QT-hys). Subject-specific quantifiers of QT-hys have been proposed as potential biomarkers, but there is no consensus on the choice of the quantifier. METHODS A comprehensive literature search was conducted to identify original articles reporting quantifiers of repolarization hysteresis from the surface ECG in humans. RESULTS Sixty articles fulfilled our inclusion criteria. Reported biomarkers were grouped under four categories. A simple mathematical model of QT/RR loop was used to illustrate differences between the methods. Category I quantifiers use direct measurement of QT time course of adaptation. They are limited to conditions where RR intervals are under strict control. Category IIa and IIb quantifiers compare QT responses during consecutive heart rate acceleration and deceleration. They are relevant when a QT/RR loop is observed, typically during exercise and recovery, but are not robust to protocol variations. Category III quantifiers evaluate the optimum RR memory in dynamic QT/RR relationship modeling. They estimate an intrinsic memory parameter independent from the nature of RR changes, but their reliability remains to be confirmed when multiple memory parameters are estimated. Promising approaches include the differentiation of short-term and long-term memory and adaptive estimation of memory parameters. CONCLUSION Model-based approaches to QT-hys assessment appear to be the most versatile, as they allow separate quantification of QT/RR dependency and QT-hys, and can be applied to a wide range of experimental settings.
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Affiliation(s)
- Hugo Gravel
- Department of Kinesiology, University of Montreal, Montréal, QC, Canada
| | - Daniel Curnier
- Department of Kinesiology, University of Montreal, Montréal, QC, Canada
| | - Nagib Dahdah
- Division of Pediatric Cardiology and CHU Ste-Justine Research Center, CHU Ste-Justine, Montréal, QC, Canada
| | - Vincent Jacquemet
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montréal, QC, Canada
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25
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Maltese PE, Orlova N, Krasikova E, Emelyanchik E, Cheremisina A, Kuscaeva A, Salmina A, Miotto R, Bonizzato A, Guerri G, Zuntini M, Nicoulina S, Bertelli M. Gene-Targeted Analysis of Clinically Diagnosed Long QT Russian Families. Int Heart J 2016; 58:81-87. [PMID: 28003625 DOI: 10.1536/ihj.16-133] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Long QT syndrome (LQTS) has great genetic heterogeneity: more than 500 mutations have been described in several genes. Despite many advances, a genetic diagnosis still cannot be established in 25-30% of patients. The aim of the present study was to perform genetic evaluation in 9 Russian families with LQTS; here we report the results of 4 positive probands and their relatives (a total of 16 individuals). All subjects underwent clinical examination, 12-lead ECG, and Holter monitoring. Genetic analysis of the 14 genes mainly involved in LQTS was performed using a next-generation sequencing approach. We identified two new mutations (KCNQ1 gene) and 6 known mutations (AKAP9, ANK2, KCNE1 and KCNJ2 genes) in 4 out of 9 probands, some of which have already been described in association with LQTS. Segregation studies suggest a possible causative role for KCNQ1 p.(Leu342Pro), AKAP9 p.(Arg1609Lys), KCNE1 p.(Asp85Asn), and KCNJ2 p.(Arg82Gln) variations. Our study confirmed the high genetic heterogeneity of this disease and highlights the difficulties to reveal clear pathogenic genotypes also in large pedigrees. To the best of our knowledge, this is the first genetic study of LQTS patients from Russian families.
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26
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Mont L, Pelliccia A, Sharma S, Biffi A, Borjesson M, Brugada Terradellas J, Carré F, Guasch E, Heidbuchel H, La Gerche A, Lampert R, McKenna W, Papadakis M, Priori SG, Scanavacca M, Thompson P, Sticherling C, Viskin S, Wilson M, Corrado D, Lip GYH, Gorenek B, Blomström Lundqvist C, Merkely B, Hindricks G, Hernández-Madrid A, Lane D, Boriani G, Narasimhan C, Marquez MF, Haines D, Mackall J, Manuel Marques-Vidal P, Corra U, Halle M, Tiberi M, Niebauer J, Piepoli M. Pre-participation cardiovascular evaluation for athletic participants to prevent sudden death: Position paper from the EHRA and the EACPR, branches of the ESC. Endorsed by APHRS, HRS, and SOLAECE. Eur J Prev Cardiol 2016; 24:41-69. [DOI: 10.1177/2047487316676042] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Lluís Mont
- Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
| | | | | | | | - Mats Borjesson
- Inst of Neuroscience and Physiology and Food, Nutrition and Sport Science and Östra University Hospital, Goteborg, Sweden
| | | | | | - Eduard Guasch
- Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
| | | | - André La Gerche
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | | | | | | | | | - Mauricio Scanavacca
- Instituto do Coração (InCor) do Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, Brazil
| | | | | | | | | | | | | | | | | | - Bela Merkely
- Semmelweis University, Heart and Vascular Center, Budapest, Hungary
| | | | - Antonio Hernández-Madrid
- Unidad De Arritmias, Servicio De Cardiologia, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Deirdre Lane
- Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | | | | | - Manlio F Marquez
- Departamento de Electrocardiología, Instituto Nacional de Cardiologia Ignacio Chavez, Tlalpan, Mexico
| | - David Haines
- Department of Cardiovascular Medicine, Beaumont Health System, Royal Oak, MI, USA
| | - Judith Mackall
- University Hospitals Case Medical Center, Cleveland, OH, USA
| | | | - Ugo Corra
- IRCCS Rehabilitation Medical Center, Cardiology Department, Salvatore Maugeri Foundation, Veruno, Italy
| | - Martin Halle
- Prevention and Sports Medicine, Technical University Munich, Munich, Germany
| | | | - Josef Niebauer
- Sports Medicine, Prevention & Rehabilitation, Paracelsus Medical University, Salzburg, Austria
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27
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Mont L, Pelliccia A, Sharma S, Biffi A, Borjesson M, Terradellas JB, Carré F, Guasch E, Heidbuchel H, Gerche AL, Lampert R, McKenna W, Papadakis M, Priori SG, Scanavacca M, Thompson P, Sticherling C, Viskin S, Wilson M, Corrado D, Lip GYH, Gorenek B, Lundqvist CB, Merkely B, Hindricks G, Hernández-Madrid A, Lane D, Boriani G, Narasimhan C, Marquez MF, Haines D, Mackall J, Marques-Vidal PM, Corra U, Halle M, Tiberi M, Niebauer J, Piepoli M. Pre-participation cardiovascular evaluation for athletic participants to prevent sudden death: Position paper from the EHRA and the EACPR, branches of the ESC. Endorsed by APHRS, HRS, and SOLAECE. Europace 2016; 19:139-163. [PMID: 27815371 DOI: 10.1093/europace/euw243] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Lluís Mont
- Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
| | | | | | | | - Mats Borjesson
- Inst of Neuroscience and Physiology and Food, Nutrition and Sport Science and Östra University Hospital, Göteborg, Sweden
| | | | | | - Eduard Guasch
- Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
| | | | - André La Gerche
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | | | | | | | | | - Mauricio Scanavacca
- Instituto do Coração (InCor) do Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | | | | | | | | | | | | | | | | | - Bela Merkely
- Semmelweis University, Heart and Vascular Center, Budapest, Hungary
| | | | - Antonio Hernández-Madrid
- Unidad De Arritmias, Servicio De Cardiologia, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | | | | | | | - Manlio F Marquez
- Departamento de Electrocardiología, Instituto Nacional de Cardiologia Ignacio Chavez, Tlalpan, Mexico
| | - David Haines
- Department of Cardiovascular Medicine, Beaumont Health System, Royal Oak, MI, USA
| | - Judith Mackall
- University Hospitals Case Medical Center, Cleveland, OH, USA
| | | | - Ugo Corra
- IRCCS Rehabilitation Medical Center, Cardiology Department, Salvatore Maugeri Foundation, Veruno, Italy
| | - Martin Halle
- Prevention and Sports Medicine, Technical University Munich, Munich, Germany
| | | | - Josef Niebauer
- Sports Medicine, Prevention & Rehabilitation, Paracelsus Medical University, Salzburg, Austria
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28
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Christiansen SL, Hertz CL, Ferrero-Miliani L, Dahl M, Weeke PE, LuCamp, Ottesen GL, Frank-Hansen R, Bundgaard H, Morling N. Genetic investigation of 100 heart genes in sudden unexplained death victims in a forensic setting. Eur J Hum Genet 2016; 24:1797-1802. [PMID: 27650965 DOI: 10.1038/ejhg.2016.118] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 07/12/2016] [Accepted: 08/05/2016] [Indexed: 11/09/2022] Open
Abstract
In forensic medicine, one-third of the sudden deaths remain unexplained after medico-legal autopsy. A major proportion of these sudden unexplained deaths (SUD) are considered to be caused by inherited cardiac diseases. Sudden cardiac death (SCD) may be the first manifestation of these diseases. The purpose of this study was to explore the yield of next-generation sequencing of genes associated with SCD in a cohort of SUD victims. We investigated 100 genes associated with cardiac diseases in 61 young (1-50 years) SUD cases. DNA was captured with the Haloplex target enrichment system and sequenced using an Illumina MiSeq. The identified genetic variants were evaluated and classified as likely, unknown or unlikely to have a functional effect. The criteria for this classification were based on the literature, databases, conservation and prediction of the effect of the variant. We found that 21 (34%) individuals carried variants with a likely functional effect. Ten (40%) of these variants were located in genes associated with cardiomyopathies and 15 (60%) of the variants in genes associated with cardiac channelopathies. Nineteen individuals carried variants with unknown functional effect. Our findings indicate that broad genetic investigation of SUD victims increases the diagnostic outcome, and the investigation should comprise genes involved in both cardiomyopathies and cardiac channelopathies.
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Affiliation(s)
- Sofie Lindgren Christiansen
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christin Løth Hertz
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Laura Ferrero-Miliani
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Dahl
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen University Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Peter Ejvin Weeke
- The Department of Cardiology, Laboratory of Molecular Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - LuCamp
- LuCamp, The Lundbeck Foundation Centre for Applied Medical Genomics in Personalized Disease Prediction, Prevention and Care, Copenhagen, Denmark
| | - Gyda Lolk Ottesen
- Section of Forensic Pathology, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rune Frank-Hansen
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henning Bundgaard
- The Unit for Inherited Cardiac Diseases, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Niels Morling
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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29
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Sugrue A, Noseworthy PA, Kremen V, Bos JM, Qiang B, Rohatgi RK, Sapir Y, Attia ZI, Brady P, Asirvatham SJ, Friedman PA, Ackerman MJ. Identification of Concealed and Manifest Long QT Syndrome Using a Novel T Wave Analysis Program. Circ Arrhythm Electrophysiol 2016; 9:CIRCEP.115.003830. [DOI: 10.1161/circep.115.003830] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 06/03/2016] [Indexed: 11/16/2022]
Abstract
Background—
Congenital long QT syndrome (LQTS) is characterized by QT prolongation. However, the QT interval itself is insufficient for diagnosis, unless the corrected QT interval is repeatedly ≥500 ms without an acquired explanation. Further, the majority of LQTS patients have a corrected QT interval below this threshold, and a significant minority has normal resting corrected QT interval values. Here, we aimed to develop and validate a novel, quantitative T wave morphological analysis program to differentiate LQTS patients from healthy controls.
Methods and Results—
We analyzed a genotyped cohort of 420 patients (22±16 years, 43% male) with either LQT1 (61%) or LQT2 (39%). ECG analysis was conducted using a novel, proprietary T wave analysis program that quantitates subtle changes in T wave morphology. The top 3 discriminating features in each ECG lead were determined and the lead with the best discrimination selected. Classification was performed using a linear discriminant classifier and validated on an untouched cohort. The top 3 features were Tpeak–Tend interval, T wave left slope, and T wave center of gravity
x
axis (last 25% of the T wave). Lead V6 had the best discrimination. It could distinguish 86.8% of LQTS patients from healthy controls. Moreover, it distinguished 83.33% of patients with concealed LQTS from controls, despite having essentially identical resting corrected QT interval values.
Conclusions—
T wave quantitative analysis on the 12-lead surface ECG provides an effective, novel tool to distinguish patients with either LQT1/LQT2 from healthy matched controls. It can provide guidance while mutation-specific genetic testing is in motion for family members.
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Affiliation(s)
- Alan Sugrue
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Peter A. Noseworthy
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Vaclav Kremen
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - J. Martijn Bos
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Bo Qiang
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Ram K. Rohatgi
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Yehu Sapir
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Zachi I. Attia
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Peter Brady
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Samuel J. Asirvatham
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Paul A. Friedman
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
| | - Michael J. Ackerman
- From the Division of Internal Medicine (A.S.), Division of Cardiovascular Diseases (P.A.N., V.K., B.Q., R.K.R., Z.I.A., P.B., S.J.A., P.A.F., M.J.A.), Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology (J.M.B., S.J.A., M.J.A.), Mayo Clinic, Rochester, MN; Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Czech Republic (V.K.); Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel (Y.S
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30
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Takahashi K, Nabeshima T, Nakayashiro M, Ganaha H. QT Dynamics During Exercise in Asymptomatic Children with Long QT Syndrome Type 3. Pediatr Cardiol 2016; 37:860-7. [PMID: 26921063 DOI: 10.1007/s00246-016-1360-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 02/13/2016] [Indexed: 01/08/2023]
Abstract
Sympathetic provocative testing is commonly used to detect the abnormal QT dynamics in long QT syndrome (LQTS) patients, particularly LQTS type 1 and type 2. However, little is known about LQTS type 3 (LQT3). We investigated QT dynamics during exercise testing in LQTS patients, particularly LQT3. This study included 37 subjects, comprising 16 genotyped LQTS patients and 21 unrelated healthy subjects without QT prolongation. LQTS patients were divided into LQT3 and non-LQT3 groups. During exercise tests using a modified Bruce protocol, 12-lead electrocardiogram monitoring was performed using a novel multifunctional electrocardiograph. QT intervals were automatically measured. The QT/heart rate (HR) relationship was visualized by plotting the beat-to-beat confluence of the recorded data. A linear regression analysis was performed to determine the QT/HR slope and intercept. Estimated QT intervals at HR 60 bpm (QT60) were calculated by the regression line formula. QT/HR slopes were steeper for each LQTS group than for the control group (P < 0.001). QT60 values demonstrated a moderate correlation with QT intervals at rest (P < 0.0001) for both groups. The corrected QT intervals (QTc) at 4 min of recovery after exercise were significantly longer in the non-LQT3 group than in the control group but were not different between the LQT3 and the control groups. Abnormal QT dynamics during exercise testing were observed in both LQT3 patients and other LQTS subtypes. This method may be useful for directing genetic testing in subjects with borderline prolonged QT intervals.
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Affiliation(s)
- Kazuhiro Takahashi
- Department of Pediatric Cardiology, Okinawa Children's Medical Center, 118-1 Arakawa, Haebaru-chou, Okinawa, 901-1193, Japan.
| | - Taisuke Nabeshima
- Department of Pediatric Cardiology, Okinawa Children's Medical Center, 118-1 Arakawa, Haebaru-chou, Okinawa, 901-1193, Japan
| | - Mami Nakayashiro
- Department of Pediatric Cardiology, Okinawa Children's Medical Center, 118-1 Arakawa, Haebaru-chou, Okinawa, 901-1193, Japan
| | - Hitoshi Ganaha
- Department of Pediatric Cardiology, Okinawa Children's Medical Center, 118-1 Arakawa, Haebaru-chou, Okinawa, 901-1193, Japan
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31
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Goldman AM, Behr ER, Semsarian C, Bagnall RD, Sisodiya S, Cooper PN. Sudden unexpected death in epilepsy genetics: Molecular diagnostics and prevention. Epilepsia 2016; 57 Suppl 1:17-25. [PMID: 26749013 DOI: 10.1111/epi.13232] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2015] [Indexed: 12/19/2022]
Abstract
Epidemiologic studies clearly document the public health burden of sudden unexpected death in epilepsy (SUDEP). Clinical and experimental studies have uncovered dynamic cardiorespiratory dysfunction, both interictally and at the time of sudden death due to epilepsy. Genetic analyses in humans and in model systems have facilitated our current molecular understanding of SUDEP. Many discoveries have been informed by progress in the field of sudden cardiac death and sudden infant death syndrome. It is becoming apparent that SUDEP genomic complexity parallels that of sudden cardiac death, and that there is a pauci1ty of analytically useful postmortem material. Because many challenges remain, future progress in SUDEP research, molecular diagnostics, and prevention rests in international, collaborative, and transdisciplinary dialogue in human and experimental translational research of sudden death.
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Affiliation(s)
- Alica M Goldman
- Department of Neurology, Baylor College of Medicine, Houston, Texas, U.S.A
| | - Elijah R Behr
- Cardiac Research Centre, ICCS, St George's University of London, London, United Kingdom
| | - Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Richard D Bagnall
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Sanjay Sisodiya
- Institute of Neurology, University College London, London, United Kingdom
| | - Paul N Cooper
- Department of Neurology, Greater Manchester Neurosciences Centre, Salford, United Kingdom.,University of Manchester, Manchester, United Kingdom
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32
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Waddell-Smith KE, Skinner JR. Update on the Diagnosis and Management of Familial Long QT Syndrome. Heart Lung Circ 2016; 25:769-76. [PMID: 27262388 DOI: 10.1016/j.hlc.2016.01.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 01/20/2016] [Indexed: 01/16/2023]
Abstract
This update was reviewed by the CSANZ Continuing Education and Recertification Committee and ratified by the CSANZ board in August 2015. Since the CSANZ 2011 guidelines, adjunctive clinical tests have proven useful in the diagnosis of LQTS and are discussed in this update. Understanding of the diagnostic and risk stratifying role of LQTS genetics is also discussed. At least 14 LQTS genes are now thought to be responsible for the disease. High-risk individuals may have multiple mutations, large gene rearrangements, C-loop mutations in KCNQ1, transmembrane mutations in KCNH2, or have certain gene modifiers present, particularly NOS1AP polymorphisms. In regards to treatment, nadolol is preferred, particularly for long QT type 2, and short acting metoprolol should not be used. Thoracoscopic left cardiac sympathectomy is valuable in those who cannot adhere to beta blocker therapy, particularly in long QT type 1. Indications for ICD therapies have been refined; and a primary indication for ICD in post-pubertal females with long QT type 2 and a very long QT interval is emerging.
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Affiliation(s)
- Kathryn E Waddell-Smith
- Green Lane Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland New Zealand; The University of Auckland, Department of Child Health, Auckland, New Zealand
| | - Jonathan R Skinner
- Green Lane Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland New Zealand; The University of Auckland, Department of Child Health, Auckland, New Zealand.
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Refaat MM, El Hage L, Steffensen AB, Hotait M, Schmitt N, Scheinman M, Badhwar N. Iron Overload Leading to Torsades de Pointes in β-Thalassemia and Long QT Syndrome. Card Electrophysiol Clin 2016; 8:247-256. [PMID: 26920202 DOI: 10.1016/j.ccep.2015.10.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The authors present a unique case of torsades de pointes in a β-thalassemia patient with early iron overload in the absence of any structural abnormalities as seen in hemochromatosis. Genetic testing showed a novel KCNQ1 gene mutation 1591C>T [Gln531Ter(X)]. Testing of the gene mutation in Xenopus laevis oocytes showed loss of function of the IKs current. The authors hypothesize that iron overload combined with the KCNQ1 gene mutation leads to prolongation of QTc and torsades de pointes.
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Affiliation(s)
- Marwan M Refaat
- Cardiology Division, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon; Department of Biochemistry and Molecular Genetics, American University of Beirut Medical Center, Beirut, Lebanon; Cardiac Electrophysiology, Cardiology, Department of Internal Medicine, American University of Beirut Faculty of Medicine and Medical Center, 3 Dag Hammarskjold Plaza, 8th Floor, New York, NY 10017, USA; Department of Biochemistry and Molecular Genetics, American University of Beirut Faculty of Medicine and Medical Center, 3 Dag Hammarskjold Plaza, 8th Floor, New York, NY 10017, USA
| | - Lea El Hage
- Division of Cardiology, Department of Medicine, University of California San Francisco Medical Center, 500 Parnassus Avenue, MUE-431, San Francisco, CA 94143-1354, USA
| | - Annette Buur Steffensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | - Mostafa Hotait
- Cardiology Division, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Nicole Schmitt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | - Melvin Scheinman
- Division of Cardiology, Department of Medicine, University of California San Francisco Medical Center, 500 Parnassus Avenue, MUE-431, San Francisco, CA 94143-1354, USA
| | - Nitish Badhwar
- Division of Cardiology, Department of Medicine, University of California San Francisco Medical Center, 500 Parnassus Avenue, MUE-431, San Francisco, CA 94143-1354, USA.
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Kuusela J, Kujala VJ, Kiviaho A, Ojala M, Swan H, Kontula K, Aalto-Setälä K. Effects of cardioactive drugs on human induced pluripotent stem cell derived long QT syndrome cardiomyocytes. SPRINGERPLUS 2016; 5:234. [PMID: 27026928 PMCID: PMC4771667 DOI: 10.1186/s40064-016-1889-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/17/2016] [Indexed: 01/08/2023]
Abstract
Human induced pluripotent stem cells (hiPSC) have enabled a major step forward in pathophysiologic studies of inherited diseases and may also prove to be valuable in in vitro drug testing. Long QT syndrome (LQTS), characterized by prolonged cardiac repolarization and risk of sudden death, may be inherited or result from adverse drug effects. Using a microelectrode array platform, we investigated the effects of six different drugs on the electrophysiological characteristics of human embryonic stem cell-derived cardiomyocytes as well as hiPSC-derived cardiomyocytes from control subjects and from patients with type 1 (LQT1) and type 2 (LQT2) of LQTS. At baseline the repolarization time was significantly longer in LQTS cells compared to controls. Isoprenaline increased the beating rate of all cell lines by 10–73 % but did not show any arrhythmic effects in any cell type. Different QT-interval prolonging drugs caused prolongation of cardiac repolarization by 3–13 % (cisapride), 10–20 % (erythromycin), 8–23 % (sotalol), 16–42 % (quinidine) and 12–27 % (E-4031), but we did not find any systematic differences in sensitivity between the control, LQT1 and LQT2 cell lines. Sotalol, quinidine and E-4031 also caused arrhythmic beats and beating arrests in some cases. In summary, the drug effects on these patient-specific cardiomyocytes appear to recapitulate clinical observations and provide further evidence that these cells can be applied for in vitro drug testing to probe their vulnerability to arrhythmia.
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Affiliation(s)
- Jukka Kuusela
- BioMediTech, University of Tampere, Finn-Medi 5, Biokatu 12, 33014 Tampere, Finland
| | - Ville J Kujala
- BioMediTech, University of Tampere, Finn-Medi 5, Biokatu 12, 33014 Tampere, Finland.,School of Engineering and Applied Science, Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA USA
| | - Anna Kiviaho
- BioMediTech, University of Tampere, Finn-Medi 5, Biokatu 12, 33014 Tampere, Finland
| | - Marisa Ojala
- BioMediTech, University of Tampere, Finn-Medi 5, Biokatu 12, 33014 Tampere, Finland
| | - Heikki Swan
- Department of Medicine, University of Helsinki, Helsinki, Finland
| | - Kimmo Kontula
- Department of Medicine, University of Helsinki, Helsinki, Finland
| | - Katriina Aalto-Setälä
- BioMediTech, University of Tampere, Finn-Medi 5, Biokatu 12, 33014 Tampere, Finland.,School of Medicine, University of Tampere, Tampere, Finland.,Heart Center, Tampere University Hospital, Tampere, Finland
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Polyunsaturated fatty acid analogs act antiarrhythmically on the cardiac IKs channel. Proc Natl Acad Sci U S A 2015; 112:5714-9. [PMID: 25901329 DOI: 10.1073/pnas.1503488112] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polyunsaturated fatty acids (PUFAs) affect cardiac excitability. Kv7.1 and the β-subunit KCNE1 form the cardiac IKs channel that is central for cardiac repolarization. In this study, we explore the prospects of PUFAs as IKs channel modulators. We report that PUFAs open Kv7.1 via an electrostatic mechanism. Both the polyunsaturated acyl tail and the negatively charged carboxyl head group are required for PUFAs to open Kv7.1. We further show that KCNE1 coexpression abolishes the PUFA effect on Kv7.1 by promoting PUFA protonation. PUFA analogs with a decreased pKa value, to preserve their negative charge at neutral pH, restore the sensitivity to open IKs channels. PUFA analogs with a positively charged head group inhibit IKs channels. These different PUFA analogs could be developed into drugs to treat cardiac arrhythmias. In support of this possibility, we show that PUFA analogs act antiarrhythmically in embryonic rat cardiomyocytes and in isolated perfused hearts from guinea pig.
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Giustetto C, Scrocco C, Schimpf R, Maury P, Mazzanti A, Levetto M, Anttonen O, Dalmasso P, Cerrato N, Gribaudo E, Wolpert C, Giachino D, Antzelevitch C, Borggrefe M, Gaita F. Usefulness of exercise test in the diagnosis of short QT syndrome. Europace 2015; 17:628-34. [DOI: 10.1093/europace/euu351] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Pedersen CT, Kay GN, Kalman J, Borggrefe M, Della-Bella P, Dickfeld T, Dorian P, Huikuri H, Kim YH, Knight B, Marchlinski F, Ross D, Sacher F, Sapp J, Shivkumar K, Soejima K, Tada H, Alexander ME, Triedman JK, Yamada T, Kirchhof P, Lip GY, Kuck KH, Mont L, Haines D, Indik J, Dimarco J, Exner D, Iesaka Y, Savelieva I. EHRA/HRS/APHRS expert consensus on ventricular arrhythmias. J Arrhythm 2014. [DOI: 10.1016/j.joa.2014.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Pedersen CT, Kay GN, Kalman J, Borggrefe M, Della-Bella P, Dickfeld T, Dorian P, Huikuri H, Kim YH, Knight B, Marchlinski F, Ross D, Sacher F, Sapp J, Shivkumar K, Soejima K, Tada H, Alexander ME, Triedman JK, Yamada T, Kirchhof P, Lip GYH, Kuck KH, Mont L, Haines D, Indik J, Dimarco J, Exner D, Iesaka Y, Savelieva I. EHRA/HRS/APHRS expert consensus on ventricular arrhythmias. Europace 2014; 16:1257-83. [PMID: 25172618 DOI: 10.1093/europace/euu194] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Shinnawi R, Gepstein L. iPCS Cell Modeling of Inherited Cardiac Arrhythmias. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2014; 16:331. [PMID: 25080030 DOI: 10.1007/s11936-014-0331-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OPINION STATEMENT The study of inherited cardiac disorders is hampered by the lack of suitable in vitro human cardiac disease models and relevant functional assays. A potential solution to this cell-sourcing challenge may be the recently described human induced pluripotent stem cell (hiPSC) technology. Pioneering studies were successful in establishing patient-specific, hiPSC-derived cardiomyocyte models of the most common inherited cardiac arrhythmogenic disorders, such as the different long QT syndrome subtypes (types 1, 2, 3, 8), overlap syndrome LQTS3/Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia (CPVT) types 1 and 2, and arrhythmogenic right ventricular cardiomyopathy (ARVC). These studies initially demonstrated the ability of the generated hiPSC models to recapitulate the disease processes in the culture dish. More recently, such studies were also able to provide new mechanistic insights into the disease processes, as well as to derive a unique drug-screening platform to test existing and novel therapeutic treatment options in an environment resembling the human physiological milieu. Moreover, initial evidence suggests that such models can help to optimize drug treatment in a personalized manner in the future. Nevertheless, several hurdles still exist for using hiPSC-based models for the aforementioned tasks, such as the hiPSC-derived cardiomyocytes' relatively immature phenotype, and also the resulting cell heterogeneity. Extensive research work is ongoing to address these challenges, as well as to add new opportunities for the field by utilizing recent advances in gene editing technologies. Here, we discuss the significant findings that hiPSC-based models have provided for each of the inherited cardiac arrhythmia syndromes so far, and the current challenges that this technique is facing.
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Affiliation(s)
- Rami Shinnawi
- The Sohnis Research Laboratory for Cardiac Electrophysiology and Regenerative Medicine, Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, POB 9649, Haifa, 31096, Israel
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Christiansen M, Hedley PL, Theilade J, Stoevring B, Leren TP, Eschen O, Sørensen KM, Tybjærg-Hansen A, Ousager LB, Pedersen LN, Frikke-Schmidt R, Aidt FH, Hansen MG, Hansen J, Bloch Thomsen PE, Toft E, Henriksen FL, Bundgaard H, Jensen HK, Kanters JK. Mutations in Danish patients with long QT syndrome and the identification of a large founder family with p.F29L in KCNH2. BMC MEDICAL GENETICS 2014; 15:31. [PMID: 24606995 PMCID: PMC4007532 DOI: 10.1186/1471-2350-15-31] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 02/18/2014] [Indexed: 01/08/2023]
Abstract
Background Long QT syndrome (LQTS) is a cardiac ion channelopathy which presents clinically with palpitations, syncope or sudden death. More than 700 LQTS-causing mutations have been identified in 13 genes, all of which encode proteins involved in the execution of the cardiac action potential. The most frequently affected genes, covering > 90% of cases, are KCNQ1, KCNH2 and SCN5A. Methods We describe 64 different mutations in 70 unrelated Danish families using a routine five-gene screen, comprising KCNQ1, KCNH2 and SCN5A as well as KCNE1 and KCNE2. Results Twenty-two mutations were found in KCNQ1, 28 in KCNH2, 9 in SCN5A, 3 in KCNE1 and 2 in KCNE2. Twenty-six of these have only been described in the Danish population and 18 are novel. One double heterozygote (1.4% of families) was found. A founder mutation, p.F29L in KCNH2, was identified in 5 “unrelated” families. Disease association, in 31.2% of cases, was based on the type of mutation identified (nonsense, insertion/deletion, frameshift or splice-site). Functional data was available for 22.7% of the missense mutations. None of the mutations were found in 364 Danish alleles and only three, all functionally characterised, were recorded in the Exome Variation Server, albeit at a frequency of < 1:1000. Conclusion The genetic etiology of LQTS in Denmark is similar to that found in other populations. A large founder family with p.F29L in KCNH2 was identified. In 48.4% of the mutations disease causation was based on mutation type or functional analysis.
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Affiliation(s)
- Michael Christiansen
- Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Ørestads Boulevard 5, 2300S, Copenhagen, Denmark.
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Nawathe PA, Kryukova Y, Oren RV, Milanesi R, Clancy CE, Lu JT, Moss AJ, Difrancesco D, Robinson RB. An LQTS6 MiRP1 mutation suppresses pacemaker current and is associated with sinus bradycardia. J Cardiovasc Electrophysiol 2013; 24:1021-7. [PMID: 23631727 DOI: 10.1111/jce.12163] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 12/20/2012] [Accepted: 03/13/2013] [Indexed: 01/20/2023]
Abstract
BACKGROUND Sinus node (SN) dysfunction is observed in some long-QT syndrome (LQTS) patients, but has not been studied as a function of LQTS genotype. LQTS6 involves mutations in the hERG β-subunit MiRP1, which also interacts with hyperpolarization-activated, cyclic nucleotide gated (HCN) channels-the molecular correlate of SN pacemaker current (If ). An LQTS registry search identified a 55-year male with M54T MiRP1 mutation, history of sinus bradycardia (39-56 bpm), and prolonged QTc. OBJECTIVE We tested if LQTS6 incorporates sinus bradycardia due to abnormal If . METHODS We transiently co-transfected neonatal rat ventricular myocytes (to study currents in a myocyte background) with human HCN4 (hHCN4, primary SN isoform) or human HCN2 (hHCN2) and one of the following: empty vector, wild-type hMiRP1 (WT), M54T hMiRP1 (M54T). Current amplitude, voltage dependence, and kinetics were measured by whole cell patch clamp. RESULTS M54T co-expression decreased HCN4 current density by 80% compared to hHCN4 alone or with WT, and also slowed HCN4 activation at physiologically relevant voltages. Neither WT nor M54T altered HCN4 voltage dependence. A computer simulation predicts that these changes in HCN4 current would decrease rate and be additive with published effects of M54T mutation on hERG kinetics on rate. CONCLUSIONS We conclude that M54T LQTS6 mutation can cause sinus bradycardia through effects on both hERG and HCN currents. Patients with other LQTS6 mutations should be examined for SN dysfunction, and the effect on HCN current determined.
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Calcium transient and sodium-calcium exchange current in human versus rabbit sinoatrial node pacemaker cells. ScientificWorldJournal 2013; 2013:507872. [PMID: 23606816 PMCID: PMC3621208 DOI: 10.1155/2013/507872] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 02/07/2013] [Indexed: 01/01/2023] Open
Abstract
There is an ongoing debate on the mechanism underlying the pacemaker activity of sinoatrial node (SAN) cells, focusing on the relative importance of the “membrane clock” and the “Ca2+ clock” in the generation of the small net membrane current that depolarizes the cell towards the action potential threshold. Specifically, the debate centers around the question whether the membrane clock-driven hyperpolarization-activated current, If, which is also known as the “funny current” or “pacemaker current,” or the Ca2+ clock-driven sodium-calcium exchange current, INaCa, is the main contributor to diastolic depolarization. In our contribution to this journal's “Special Issue on Cardiac Electrophysiology,” we present a numerical reconstruction of If and
INaCa in isolated rabbit and human SAN pacemaker cells based on experimental data on action potentials, If, and intracellular calcium concentration ([Ca2+]i) that we have acquired from these cells. The human SAN pacemaker cells have a smaller If, a weaker [Ca2+]i transient, and a smaller INaCa than the rabbit cells. However, when compared to the diastolic net membrane current, INaCa is of similar size in human and rabbit SAN pacemaker cells, whereas If is smaller in human than in rabbit cells.
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Aziz PF, Wieand TS, Ganley J, Henderson J, McBride M, Shah MJ. Do LQTS gene single nucleotide polymorphisms alter QTc intervals at rest and during exercise stress testing? Ann Noninvasive Electrocardiol 2013; 18:288-93. [PMID: 23714088 DOI: 10.1111/anec.12037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The impact of harboring, genetic variants or single nucleotide polymorphisms (LQT-PM) on the repolarization response during exercise and recovery is unknown. OBJECTIVE To assess the QTc interval adaptation during exercise stress testing (EST) in children with LQT polymorphisms compared to a group of age and gender matched normal controls. METHODS One hundred forty-eight patients were age and gender matched into two groups: LQT-PM and control. Each patient underwent a uniform exercise protocol employing a cycle ergometer followed by a 9 minute recovery phase with continuous 12-lead electrocardiogram (ECG) monitoring. Intervals (RR, QT and QTc) at rest (supine), peak exercise and in recovery (1, 3, 5, 7, and 9 minutes) were measured. RESULTS Forty-three patients were positive for LQT-PM and the control group consisted of 105 patients. A total of 83 SNPs were identified: SCN5A n = 31 (37%), KCNE1 n = 29 (35%), KCNH2 n = 20 (24%), KCNQ1 n = 2 (2%) and KCNE2 n = 1 (1%). The QTc interval measurements of the LQT-PM were longer at rest, peak exercise and all phases of recovery when compared to the control group. Neither group demonstrated abnormal QTc interval adaptation in response to exercise. Patients with homozygous SNPs had longer resting QTc intervals when compared to patients with only heterozygous SNPs (435 ± 23 ms vs. 415 ± 20 ms, respectively, P value <0.006). CONCLUSIONS Individuals with LQT-PM may have longer QTc intervals at rest as well as at peak exercise and all phases of the recovery period compared to normal controls. Additionally, subjects with homozygous SNPs had longer resting QTc intervals when compared to those with only heterozygous SNPs.
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Affiliation(s)
- Peter F Aziz
- Cleveland Clinic Foundation, Department of Pediatric Cardiology and the Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA.
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Abstract
Repolarization syndromes, including early repolarization, Brugada, and short and long QT, have been implicated increasingly as causes of sudden cardiac death (SCD) despite no obvious mechanical cardiac abnormalities. So-called idiopathic ventricular fibrillation is now often reassigned to one of the aforementioned entities. Underlying causes are diverse; genetic mutation has been proven in many but not all cases. Although high-risk individuals generally can be identified, most of the potential victim pool is still unknown and cannot be discovered at this time. Awareness of these entities' existence, knowledge of family history, and 12-lead electrocardiography are the initial steps toward preventing SCD in this population. Underlying mechanisms for ventricular tachycardia/fibrillation in such individuals include phase 2 reentry, early after depolarization, and vortex reentry. For the time-being, although most forms of long QT syndrome can be treated with β-blockers, an implantable cardioverter-defibrillator remains the only definitive therapy for the prevention of arrhythmic death among high-risk populations.
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Hekkala AM, Väänänen H, Swan H, Viitasalo M, Toivonen L. T-wave morphology after epinephrine bolus may reveal silent long QT syndrome mutation carriers. J Electrocardiol 2012; 45:368-372. [PMID: 22560601 DOI: 10.1016/j.jelectrocard.2012.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Indexed: 10/28/2022]
Abstract
BACKGROUND Long QT syndrome (LQTS) gene mutation carriers with indeterminate electrocardiogram frequently escape clinical diagnosis. We assessed the use of epinephrine bolus injection in revealing T-wave abnormalities. METHODS We recruited 30 genotyped asymptomatic LQTS gene carriers with nondiagnostic QT interval and 15 controls. Electrocardiogram was recorded with body surface potential mapping after an intravenous epinephrine bolus. T-wave morphology was determined as normal, biphasic, inverted, bifid, or combined pattern. RESULTS Long QT syndrome carriers and healthy controls had different T-wave profiles (P = .027). Of controls, 12 (80%) of 15 had no change or biphasic appearance, whereas only 10 (33%) of 30 of LQTS carriers had so. Bifid or combined pattern occurred in 15 (50%) of 30 in LQTS and in 6 (60%) of 10 in the LQT3 subgroup but only in 1 (7%) of 15 of healthy. CONCLUSIONS Modification of ventricular repolarization with low-dose epinephrine injection helps to distinguish silent LQTS mutation carriers. This concerns also the LQT3 subtype, which may escape tests.
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Affiliation(s)
- Anna-Mari Hekkala
- Helsinki University Central Hospital, Department of Cardiology, Helsinki, Finland.
| | - Heikki Väänänen
- Aalto University, Department of Biomedical Engineering and Computational Science, Espoo, Finland
| | - Heikki Swan
- Helsinki University Central Hospital, Department of Cardiology, Helsinki, Finland
| | - Matti Viitasalo
- Helsinki University Central Hospital, Department of Cardiology, Helsinki, Finland
| | - Lauri Toivonen
- Helsinki University Central Hospital, Department of Cardiology, Helsinki, Finland
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Costa J, Lopes CM, Barsheshet A, Moss AJ, Migdalovich D, Ouellet G, McNitt S, Polonsky S, Robinson JL, Zareba W, Ackerman MJ, Benhorin J, Kaufman ES, Platonov PG, Shimizu W, Towbin JA, Vincent GM, Wilde AAM, Goldenberg I. Combined assessment of sex- and mutation-specific information for risk stratification in type 1 long QT syndrome. Heart Rhythm 2012; 9:892-8. [PMID: 22293141 DOI: 10.1016/j.hrthm.2012.01.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Indexed: 01/08/2023]
Abstract
BACKGROUND Men and women with type 1 long QT syndrome (LQT1) exhibit time-dependent differences in the risk for cardiac events. OBJECTIVE We hypothesized that sex-specific risk for LQT1 is related to the location and function of the disease-causing mutation in the KCNQ1 gene. METHODS The risk for life-threatening cardiac events (comprising aborted cardiac arrest [ACA] or sudden cardiac death [SCD]) from birth through age 40 years was assessed among 1051 individuals with LQT1 (450 men and 601 women) by the location and function of the LQT1-causing mutation (prespecified as mutations in the intracellular domains linking the membrane-spanning segments [ie, S2-S3 and S4-S5 cytoplasmic loops] involved in adrenergic channel regulation vs other mutations). RESULTS Multivariate analysis showed that during childhood (age group: 0-13 years) men had >2-fold (P < .003) increased risk for ACA/SCD than did women, whereas after the onset of adolescence the risk for ACA/SCD was similar between men and women (hazard ratio = 0.89 [P = .64]). The presence of cytoplasmic-loop mutations was associated with a 2.7-fold (P < .001) increased risk for ACA/SCD among women, but it did not affect the risk among men (hazard ratio 1.37; P = .26). Time-dependent syncope was associated with a more pronounced risk-increase among men than among women (hazard ratio 4.73 [P < .001] and 2.43 [P = .02], respectively), whereas a prolonged corrected QT interval (≥ 500 ms) was associated with a higher risk among women than among men. CONCLUSION Our findings suggest that the combined assessment of clinical and mutation location/functional data can be used to identify sex-specific risk factors for life-threatening events for patients with LQT1.
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Affiliation(s)
- Jason Costa
- Cardiology Division, University of Rochester Medical Center, Rochester, NY 14642, USA
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Sy RW, van der Werf C, Chattha IS, Chockalingam P, Adler A, Healey JS, Perrin M, Gollob MH, Skanes AC, Yee R, Gula LJ, Leong-Sit P, Viskin S, Klein GJ, Wilde AA, Krahn AD. Derivation and Validation of a Simple Exercise-Based Algorithm for Prediction of Genetic Testing in Relatives of LQTS Probands. Circulation 2011; 124:2187-94. [DOI: 10.1161/circulationaha.111.028258] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Genetic testing can diagnose long-QT syndrome (LQTS) in asymptomatic relatives of patients with an identified mutation; however, it is costly and subject to availability. The accuracy of a simple algorithm that incorporates resting and exercise ECG parameters for screening LQTS in asymptomatic relatives was evaluated, with genetic testing as the gold standard.
Methods and Results—
Asymptomatic first-degree relatives of genetically characterized probands were recruited from 5 centers. QT intervals were measured at rest, during exercise, and during recovery. Receiver operating characteristics were used to establish optimal cutoffs. An algorithm for identifying LQTS carriers was developed in a derivation cohort and validated in an independent cohort. The derivation cohort consisted of 69 relatives (28 with LQT1, 20 with LQT2, and 21 noncarriers). Mean age was 35±18 years, and resting corrected QT interval (QTc) was 466±39 ms. Abnormal resting QTc (females ≥480 ms; males ≥470 ms) was 100% specific for gene carrier status, but was observed in only 48% of patients; however, mutations were observed in 68% and 42% of patients with a borderline or normal resting QTc, respectively. Among these patients, 4-minute recovery QTc ≥445 ms correctly restratified 22 of 25 patients as having LQTS and 19 of 21 patients as being noncarriers. The combination of resting and 4-minute recovery QTc in a screening algorithm yielded a sensitivity of 0.94 and specificity of 0.90 for detecting LQTS carriers. When applied to the validation cohort (n=152; 58 with LQT1, 61 with LQT2, and 33 noncarriers; QTc=443±47 ms), sensitivity was 0.92 and specificity was 0.82.
Conclusions—
A simple algorithm that incorporates resting and exercise-recovery QTc is useful in identifying LQTS in asymptomatic relatives.
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Affiliation(s)
- Raymond W. Sy
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Christian van der Werf
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Ishvinder S. Chattha
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Priya Chockalingam
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Arnon Adler
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Jeffrey S. Healey
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Mark Perrin
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Michael H. Gollob
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Allan C. Skanes
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Raymond Yee
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Lorne J. Gula
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Peter Leong-Sit
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Sami Viskin
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - George J. Klein
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Arthur A. Wilde
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
| | - Andrew D. Krahn
- From the University of Western Ontario, London, ON, Canada (R.W.S., I.S.C., A.C.S., R.Y., L.J.G., P.L.-S., G.J.K., A.D.K.); Academic Medical Center, Amsterdam, Netherlands (C.V.d.W., P.C., A.A.W.); Tel Aviv University, Tel Aviv, Israel (A.A., S.V.); McMaster University, Hamilton, ON, Canada (J.S.H.); and University of Ottawa, Ottawa, ON, Canada (M.P., M.H.G.)
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Lahti AL, Kujala VJ, Chapman H, Koivisto AP, Pekkanen-Mattila M, Kerkelä E, Hyttinen J, Kontula K, Swan H, Conklin BR, Yamanaka S, Silvennoinen O, Aalto-Setälä K. Model for long QT syndrome type 2 using human iPS cells demonstrates arrhythmogenic characteristics in cell culture. Dis Model Mech 2011; 5:220-30. [PMID: 22052944 PMCID: PMC3291643 DOI: 10.1242/dmm.008409] [Citation(s) in RCA: 213] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Long QT syndrome (LQTS) is caused by functional alterations in cardiac ion channels and is associated with prolonged cardiac repolarization time and increased risk of ventricular arrhythmias. Inherited type 2 LQTS (LQT2) and drug-induced LQTS both result from altered function of the hERG channel. We investigated whether the electrophysiological characteristics of LQT2 can be recapitulated in vitro using induced pluripotent stem cell (iPSC) technology. Spontaneously beating cardiomyocytes were differentiated from two iPSC lines derived from an individual with LQT2 carrying the R176W mutation in the KCNH2 (HERG) gene. The individual had been asymptomatic except for occasional palpitations, but his sister and father had died suddenly at an early age. Electrophysiological properties of LQT2-specific cardiomyocytes were studied using microelectrode array and patch-clamp, and were compared with those of cardiomyocytes derived from control cells. The action potential duration of LQT2-specific cardiomyocytes was significantly longer than that of control cardiomyocytes, and the rapid delayed potassium channel (IKr) density of the LQT2 cardiomyocytes was significantly reduced. Additionally, LQT2-derived cardiac cells were more sensitive than controls to potentially arrhythmogenic drugs, including sotalol, and demonstrated arrhythmogenic electrical activity. Consistent with clinical observations, the LQT2 cardiomyocytes demonstrated a more pronounced inverse correlation between the beating rate and repolarization time compared with control cells. Prolonged action potential is present in LQT2-specific cardiomyocytes derived from a mutation carrier and arrhythmias can be triggered by a commonly used drug. Thus, the iPSC-derived, disease-specific cardiomyocytes could serve as an important platform to study pathophysiological mechanisms and drug sensitivity in LQT2.
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Affiliation(s)
- Anna L Lahti
- Institute of Biomedical Technology, University of Tampere, Tampere, Finland
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