1
|
Wolfes J, Uphoff J, Kemena S, Wegner F, Rath B, Eckardt L, Frommeyer G, Ellermann C. Divergent electrophysiologic action of dapagliflozin and empagliflozin on ventricular and atrial tachyarrhythmias in isolated rabbit hearts. Front Cardiovasc Med 2024; 11:1369250. [PMID: 38455723 PMCID: PMC10918010 DOI: 10.3389/fcvm.2024.1369250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 02/12/2024] [Indexed: 03/09/2024] Open
Abstract
Background The use of SGLT-2 inhibitors has revolutionized heart failure therapy. Evidence suggests a reduced incidence of ventricular and atrial arrhythmias in patients with dapagliflozin or empagliflozin treatment. It is unclear to what extent the reduced arrhythmia burden is due to direct effects of the SGLT2 inhibitors or is solely a marker of improved cardiac function. Methods One hundred five rabbit hearts were allocated to eight groups and retrogradely perfused, employing a Langendorff setup. Action potential duration at 90% of repolarization (APD90), QT intervals, effective refractory periods, conduction velocity, and dispersion of repolarization were obtained with monophasic action potential catheters. A model for tachyarrhythmias was established with the IKr blocker erythromycin for QT prolongation associated proarrhythmia as well as the potassium channel opener pinacidil for a short-QT model. An atrial fibrillation (AF) model was created with isoproterenol and acetylcholine. With increasing concentrations of both SGLT2 inhibitors, reductions in QT intervals and APD90 were observed, accompanied by a slight increase in ventricular arrhythmia episodes. During drug-induced proarrhythmia, empagliflozin succeeded in decreasing QT intervals, APD90, and VT burden whereas dapagliflozin demonstrated no significant effects. In the presence of pinacidil induced arrhythmogenicity, neither SGLT2 inhibitor had a significant impact on cardiac electrophysiology. In the AF setting, perfusion with dapagliflozin showed significant suppression of AF in the course of restitution of electrophysiological parameters whereas empagliflozin showed no significant effect on atrial fibrillation incidence. Conclusion In this model, empagliflozin and dapagliflozin demonstrated opposite antiarrhythmic properties. Empagliflozin reduced ventricular tachyarrhythmias whereas dapagliflozin showed effective suppression of atrial arrhythmias.
Collapse
Affiliation(s)
- Julian Wolfes
- Department of Cardiology II, Electrophysiology, University Hospital Münster, Münster, Germany
| | | | | | | | | | | | | | | |
Collapse
|
2
|
Hanington OP, Armstrong C, Pierre G, Stuart G, Hancox JC. Left ventricular noncompaction cardiomyopathy and short QT syndrome due to primary carnitine deficiency. Ann Noninvasive Electrocardiol 2023; 28:e13077. [PMID: 37658577 PMCID: PMC10646383 DOI: 10.1111/anec.13077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 07/06/2023] [Accepted: 07/26/2023] [Indexed: 09/03/2023] Open
Abstract
We report the case of a 13-year-old female patient presenting with presyncope and palpitations. Her electrocardiogram revealed an abbreviation of the rate-corrected QT interval with imaging showing significant left ventricular dysfunction. Carnitine levels were measured as part of her diagnostic workup, discovering a rare, reversible cause of short QT syndrome (SQTS) and associated cardiomyopathy-primary carnitine deficiency (PCD) caused by a homozygous mutation in the SLC22A5 gene, leading to an in-frame deletion mutation (NP_003051.1:p.Phe23del) affecting the organic cation transporter 2 (OCTN2) protein. Following the treatment with oral carnitine supplementation, her QT interval returned to within the normal range with significant improvement in left ventricular function.
Collapse
Affiliation(s)
- Oliver P. Hanington
- Cardiovascular Research Laboratories, School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | | | | | - Graham Stuart
- Bristol Heart InstituteBristolUK
- Bristol Royal Hospital for Sick ChildrenBristolUK
| | - Jules C. Hancox
- Cardiovascular Research Laboratories, School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| |
Collapse
|
3
|
Pasero E, Gaita F, Randazzo V, Meynet P, Cannata S, Maury P, Giustetto C. Artificial Intelligence ECG Analysis in Patients with Short QT Syndrome to Predict Life-Threatening Arrhythmic Events. Sensors (Basel) 2023; 23:8900. [PMID: 37960599 PMCID: PMC10649184 DOI: 10.3390/s23218900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/23/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023]
Abstract
Short QT syndrome (SQTS) is an inherited cardiac ion-channel disease related to an increased risk of sudden cardiac death (SCD) in young and otherwise healthy individuals. SCD is often the first clinical presentation in patients with SQTS. However, arrhythmia risk stratification is presently unsatisfactory in asymptomatic patients. In this context, artificial intelligence-based electrocardiogram (ECG) analysis has never been applied to refine risk stratification in patients with SQTS. The purpose of this study was to analyze ECGs from SQTS patients with the aid of different AI algorithms to evaluate their ability to discriminate between subjects with and without documented life-threatening arrhythmic events. The study group included 104 SQTS patients, 37 of whom had a documented major arrhythmic event at presentation and/or during follow-up. Thirteen ECG features were measured independently by three expert cardiologists; then, the dataset was randomly divided into three subsets (training, validation, and testing). Five shallow neural networks were trained, validated, and tested to predict subject-specific class (non-event/event) using different subsets of ECG features. Additionally, several deep learning and machine learning algorithms, such as Vision Transformer, Swin Transformer, MobileNetV3, EfficientNetV2, ConvNextTiny, Capsule Networks, and logistic regression were trained, validated, and tested directly on the scanned ECG images, without any manual feature extraction. Furthermore, a shallow neural network, a 1-D transformer classifier, and a 1-D CNN were trained, validated, and tested on ECG signals extracted from the aforementioned scanned images. Classification metrics were evaluated by means of sensitivity, specificity, positive and negative predictive values, accuracy, and area under the curve. Results prove that artificial intelligence can help clinicians in better stratifying risk of arrhythmia in patients with SQTS. In particular, shallow neural networks' processing features showed the best performance in identifying patients that will not suffer from a potentially lethal event. This could pave the way for refined ECG-based risk stratification in this group of patients, potentially helping in saving the lives of young and otherwise healthy individuals.
Collapse
Affiliation(s)
- Eros Pasero
- Department of Electronics and Telecommunications, Politecnico di Torino, 10129 Turin, Italy
| | - Fiorenzo Gaita
- Cardiology Unit, J Medical, 1015 Turin, Italy;
- Department of Medical Sciences, University of Turin, 10124 Turin, Italy;
| | - Vincenzo Randazzo
- Department of Electronics and Telecommunications, Politecnico di Torino, 10129 Turin, Italy
| | - Pierre Meynet
- Department of Medical Sciences, University of Turin, 10124 Turin, Italy;
- Division of Cardiology, Città della Salute e della Scienza Hospital, 10126 Turin, Italy
| | - Sergio Cannata
- Department of Electronics and Telecommunications, Politecnico di Torino, 10129 Turin, Italy
| | - Philippe Maury
- Department of Cardiology, University Hospital Rangueil, 31400 Toulouse, France;
| | - Carla Giustetto
- Department of Medical Sciences, University of Turin, 10124 Turin, Italy;
- Division of Cardiology, Città della Salute e della Scienza Hospital, 10126 Turin, Italy
| |
Collapse
|
4
|
Hancox JC, Du CY, Butler A, Zhang Y, Dempsey CE, Harmer SC, Zhang H. Pro-arrhythmic effects of gain-of-function potassium channel mutations in the short QT syndrome. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220165. [PMID: 37122211 PMCID: PMC10150212 DOI: 10.1098/rstb.2022.0165] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
The congenital short QT syndrome (SQTS) is a rare condition characterized by abbreviated rate-corrected QT (QTc) intervals on the electrocardiogram and by increased susceptibility to both atrial and ventricular arrhythmias and sudden death. Although mutations to multiple genes have been implicated in the SQTS, evidence of causality is particularly strong for the first three (SQT1-3) variants: these result from gain-of-function mutations in genes that encode K+ channel subunits responsible, respectively, for the IKr, IKs and IK1 cardiac potassium currents. This article reviews evidence for the impact of SQT1-3 missense potassium channel gene mutations on the electrophysiological properties of IKr, IKs and IK1 and of the links between these changes and arrhythmia susceptibility. Data from experimental and simulation studies and future directions for research in this field are considered. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
Collapse
Affiliation(s)
- J C Hancox
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
- Biological Physics Group, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - C Y Du
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
| | - A Butler
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
| | - Y Zhang
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
| | - C E Dempsey
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - S C Harmer
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
| | - H Zhang
- Biological Physics Group, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| |
Collapse
|
5
|
Asatryan B, Barth AS. Sex-related differences in incidence, phenotype and risk of sudden cardiac death in inherited arrhythmia syndromes. Front Cardiovasc Med 2023; 9:1010748. [PMID: 36684594 PMCID: PMC9845907 DOI: 10.3389/fcvm.2022.1010748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 12/08/2022] [Indexed: 01/06/2023] Open
Abstract
Inherited Arrhythmia Syndromes (IAS) including long QT and Brugada Syndrome, are characterized by life-threatening arrhythmias in the absence of apparent structural heart disease and are caused by pathogenic variants in genes encoding cardiac ion channels or associated proteins. Studies of large pedigrees of families affected by IAS have demonstrated incomplete penetrance and variable expressivity. Biological sex is one of several factors that have been recognized to modulate disease severity in IAS. There is a growing body of evidence linking sex hormones to the susceptibility to arrhythmias, yet, many sex-specific disease aspects remain underrecognized as female sex and women with IAS are underinvestigated and findings from male-predominant cohorts are often generalized to both sexes with minimal to no consideration of relevant sex-associated differences in prevalence, disease manifestations and outcome. In this review, we highlight current knowledge of sex-related biological differences in normal cardiac electrophysiology and sex-associated factors that influence IAS phenotypes.
Collapse
Affiliation(s)
- Babken Asatryan
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Andreas S. Barth
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States,*Correspondence: Andreas S. Barth ✉
| |
Collapse
|
6
|
Martínez-Barrios E, Cesar S, Cruzalegui J, Hernandez C, Arbelo E, Fiol V, Brugada J, Brugada R, Campuzano O, Sarquella-Brugada G. Clinical Genetics of Inherited Arrhythmogenic Disease in the Pediatric Population. Biomedicines 2022; 10:106. [PMID: 35052786 PMCID: PMC8773373 DOI: 10.3390/biomedicines10010106] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/27/2021] [Accepted: 12/31/2021] [Indexed: 12/19/2022] Open
Abstract
Sudden death is a rare event in the pediatric population but with a social shock due to its presentation as the first symptom in previously healthy children. Comprehensive autopsy in pediatric cases identify an inconclusive cause in 40-50% of cases. In such cases, a diagnosis of sudden arrhythmic death syndrome is suggested as the main potential cause of death. Molecular autopsy identifies nearly 30% of cases under 16 years of age carrying a pathogenic/potentially pathogenic alteration in genes associated with any inherited arrhythmogenic disease. In the last few years, despite the increasing rate of post-mortem genetic diagnosis, many families still remain without a conclusive genetic cause of the unexpected death. Current challenges in genetic diagnosis are the establishment of a correct genotype-phenotype association between genes and inherited arrhythmogenic disease, as well as the classification of variants of uncertain significance. In this review, we provide an update on the state of the art in the genetic diagnosis of inherited arrhythmogenic disease in the pediatric population. We focus on emerging publications on gene curation for genotype-phenotype associations, cases of genetic overlap and advances in the classification of variants of uncertain significance. Our goal is to facilitate the translation of genetic diagnosis to the clinical area, helping risk stratification, treatment and the genetic counselling of families.
Collapse
Affiliation(s)
- Estefanía Martínez-Barrios
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Sergi Cesar
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - José Cruzalegui
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Clara Hernandez
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Elena Arbelo
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, 08036 Barcelona, Spain
| | - Victoria Fiol
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Josep Brugada
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, 08036 Barcelona, Spain
| | - Ramon Brugada
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
- Cardiology Service, Hospital Josep Trueta, University of Girona, 17007 Girona, Spain
| | - Oscar Campuzano
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Georgia Sarquella-Brugada
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
| |
Collapse
|
7
|
El‐Battrawy I, Lan H, Cyganek L, Maywald L, Zhong R, Zhang F, Xu Q, Lee J, Duperrex E, Hierlemann A, Saguner AM, Duru F, Kovacs B, Huang M, Liao Z, Albers S, Müller J, Dinkel H, Rose L, Hohn A, Yang Z, Qiao L, Li Y, Lang S, Kleinsorge M, Mügge A, Aweimer A, Fan X, Diecke S, Akin I, Li G, Zhou X. Deciphering the pathogenic role of a variant with uncertain significance for short QT and Brugada syndromes using gene-edited human-induced pluripotent stem cell-derived cardiomyocytes and preclinical drug screening. Clin Transl Med 2021; 11:e646. [PMID: 34954893 PMCID: PMC8710296 DOI: 10.1002/ctm2.646] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 10/24/2021] [Accepted: 10/30/2021] [Indexed: 12/22/2022] Open
Affiliation(s)
- Ibrahim El‐Battrawy
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
- DZHK (German Center for Cardiovascular Research)Partner Site Heidelberg‐Mannheim and GöttingenMannheimGermany
- Department of Cardiology and AngiologyBergmannsheil Bochum, Medical Clinic IIRuhr UniversityBochumGermany
| | - Huan Lan
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan ProvinceInstitute of Cardiovascular Research, Southwest Medical UniversityLuzhouChina
| | - Lukas Cyganek
- Stem Cell Unit, Clinic for Cardiology and PneumologyUniversity Medical Center GöttingenGöttingenGermany
- DZHK (German Center for Cardiovascular Research)Partner Site Heidelberg‐Mannheim and GöttingenMannheimGermany
| | - Lasse Maywald
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
- DZHK (German Center for Cardiovascular Research)Partner Site Heidelberg‐Mannheim and GöttingenMannheimGermany
| | - Rujia Zhong
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Feng Zhang
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Qiang Xu
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Jihyun Lee
- Department of Biosystems Science and EngineeringBioengineering LaboratoryBaselSwitzerland
| | - Eliane Duperrex
- Department of Biosystems Science and EngineeringBioengineering LaboratoryBaselSwitzerland
| | - Andreas Hierlemann
- Department of Biosystems Science and EngineeringBioengineering LaboratoryBaselSwitzerland
| | - Ardan M. Saguner
- Department of CardiologyElectrophysiology DivisionUniversity Heart Center ZurichZurichSwitzerland
| | - Firat Duru
- Department of CardiologyElectrophysiology DivisionUniversity Heart Center ZurichZurichSwitzerland
| | - Boldizsar Kovacs
- Department of CardiologyElectrophysiology DivisionUniversity Heart Center ZurichZurichSwitzerland
| | - Mengying Huang
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Zhenxing Liao
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Sebastian Albers
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
- DZHK (German Center for Cardiovascular Research)Partner Site Heidelberg‐Mannheim and GöttingenMannheimGermany
| | - Jonas Müller
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
- DZHK (German Center for Cardiovascular Research)Partner Site Heidelberg‐Mannheim and GöttingenMannheimGermany
| | - Hendrik Dinkel
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
- DZHK (German Center for Cardiovascular Research)Partner Site Heidelberg‐Mannheim and GöttingenMannheimGermany
| | - Lena Rose
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Alyssa Hohn
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Zhen Yang
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Lin Qiao
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Yingrui Li
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | - Siegfried Lang
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
- DZHK (German Center for Cardiovascular Research)Partner Site Heidelberg‐Mannheim and GöttingenMannheimGermany
| | - Mandy Kleinsorge
- Stem Cell Unit, Clinic for Cardiology and PneumologyUniversity Medical Center GöttingenGöttingenGermany
- Department of CardiologyElectrophysiology DivisionUniversity Heart Center ZurichZurichSwitzerland
| | - Andreas Mügge
- Department of Cardiology and AngiologyBergmannsheil Bochum, Medical Clinic IIRuhr UniversityBochumGermany
| | - Assem Aweimer
- Department of Cardiology and AngiologyBergmannsheil Bochum, Medical Clinic IIRuhr UniversityBochumGermany
| | - Xuehui Fan
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
| | | | - Ibrahim Akin
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
- DZHK (German Center for Cardiovascular Research)Partner Site Heidelberg‐Mannheim and GöttingenMannheimGermany
| | - Guang Li
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan ProvinceInstitute of Cardiovascular Research, Southwest Medical UniversityLuzhouChina
| | - Xiaobo Zhou
- First Department of MedicineFaculty of MedicineUniversity Medical Centre Mannheim (UMM), University of HeidelbergMannheimGermany
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan ProvinceInstitute of Cardiovascular Research, Southwest Medical UniversityLuzhouChina
- DZHK (German Center for Cardiovascular Research)Partner Site Heidelberg‐Mannheim and GöttingenMannheimGermany
| |
Collapse
|
8
|
Mantri N, Lu M, Zaroff JG, Risch N, Hoffmann T, Oni-Orisan A, Lee C, Jorgenson E, Iribarren C. QT Interval Dynamics and Cardiovascular Outcomes: A Cohort Study in an Integrated Health Care Delivery System. J Am Heart Assoc 2021; 10:e018513. [PMID: 34581201 PMCID: PMC8649135 DOI: 10.1161/jaha.120.018513] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Long QT has been associated with ventricular dysrhythmias, cardiovascular disease (CVD) mortality, and sudden cardiac death. However, no studies to date have investigated the dynamics of within‐person QT change over time in relation to risk of incident CVD and all‐cause mortality in a real‐world setting. Methods and Results A cohort study among members of an integrated health care delivery system in Northern California including 61 455 people (mean age, 62 years; 60% women, 42% non‐White) with 3 or more ECGs (baseline in 2005–2009; mean±SD follow‐up time, 7.6±2.6 years). In fully adjusted models, tertile 3 versus tertile 1 of average QT corrected (using the Fridericia correction) was associated with cardiac arrest (hazard ratio [HR], 1.66), heart failure (HR, 1.62), ventricular dysrhythmias (HR, 1.56), all CVD (HR, 1.31), ischemic heart disease (HR, 1.28), total stroke (HR, 1.18), and all‐cause mortality (HR, 1.24). Tertile 3 versus tertile 2 of the QT corrected linear slope was associated with cardiac arrest (HR, 1.22), ventricular dysrhythmias (HR, 1.12), and all‐cause mortality (HR, 1.09). Tertile 3 versus tertile 1 of the QT corrected root mean squared error was associated with ventricular dysrhythmias (HR, 1.34), heart failure (HR, 1.28), all‐cause mortality (HR, 1.20), all CVD (HR, 1.14), total stroke (HR, 1.08), and ischemic heart disease (HR, 1.07). Conclusions Our results demonstrate improved predictive ability for CVD outcomes using longitudinal information from serial ECGs. Long‐term average QT corrected was more strongly associated with CVD outcomes than the linear slope or the root mean squared error. This new evidence is clinically relevant because ECGs are frequently used, noninvasive, and inexpensive.
Collapse
Affiliation(s)
- Neha Mantri
- Department of Cardiology Kaiser Permanente San Francisco Medical Center San Francisco CA
| | - Meng Lu
- Division of Research Kaiser Permanente Oakland CA
| | - Jonathan G Zaroff
- Department of Cardiology Kaiser Permanente San Francisco Medical Center San Francisco CA
| | - Neil Risch
- Institute for Human Genetics University of California, San Francisco CA
| | - Thomas Hoffmann
- Institute for Human Genetics University of California, San Francisco CA
| | | | | | | | | |
Collapse
|
9
|
Affiliation(s)
- Jitae A Kim
- Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Mihail G Chelu
- Section of Cardiology, Baylor College of Medicine, Houston, Texas
| |
Collapse
|
10
|
Huang M, Liao Z, Li X, Yang Z, Fan X, Li Y, Zhao Z, Lang S, Cyganek L, Zhou X, Akin I, Borggrefe M, El-Battrawy I. Effects of Antiarrhythmic Drugs on hERG Gating in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes From a Patient With Short QT Syndrome Type 1. Front Pharmacol 2021; 12:675003. [PMID: 34025432 PMCID: PMC8138577 DOI: 10.3389/fphar.2021.675003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/26/2021] [Indexed: 12/17/2022] Open
Abstract
Aims: The short QT syndrome type 1 (SQT1) is linked to hERG channel mutations (e.g., N588K). Drug effects on hERG channel gating kinetics in SQT1-cells have not been investigated. Methods: This study used hiPSC-CMs of a healthy donor and a SQT1-patient carrying the N588K mutation and patch clamp to examine the drug effects on hERG channel gating kinetics. Results: Ajmaline, amiodarone, ivabradine, flecainide, quinidine, mexiletine and ranolazine inhibited the hERG channel current (IKr) less strongly in hiPSC-CMs from the SQTS1-patient (SQT1-hiPSC-CMs) comparing with cells from the healthy donor (donor-hiPSC-CMs). Quinidine and mexiletine reduced, but ajmaline, amiodarone, ivabradine and ranolazine increased the time to peak of IKr similarly in SQT1-hiPSC-CMs and donor-hiPSC-CMs. Although regarding the shift of activation and inactivation curves, tested drugs showed differential effects in donor- and SQT1-hiPSC-CMs, quinidine, ajmaline, ivabradine and mexiletine but not amiodarone, flecainide and ranolazine reduced the window current in SQT1-hiPSC-CMs. Quinidine, ajmaline, ivabradine and mexiletine differentially changed the time constant of recovery from inactivation, but all of them increased the time constant of deactivation in SQT1-hiPSC-CMs. Conclusion: The window current-reducing and deactivation-slowing effects may be important for the antiarrhythmic effect of ajmaline, ivabradine, quinidine and mexiletine in SQT1-cells. This information may be helpful for selecting drugs for treating SQT1-patients with hERG channel mutation.
Collapse
Affiliation(s)
- Mengying Huang
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Zhenxing Liao
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,North Sichuan Medical College, Nanchong, China
| | - Xin Li
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,College of Medical Technology, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Zhen Yang
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,North Sichuan Medical College, Nanchong, China
| | - Xuehui Fan
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Yingrui Li
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Zhihan Zhao
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Siegfried Lang
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Lukas Cyganek
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany.,Stem Cell Unit, Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Xiaobo Zhou
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China.,DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Ibrahim Akin
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Martin Borggrefe
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Ibrahim El-Battrawy
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| |
Collapse
|
11
|
Dewi IP, Dharmadjati BB. Short QT syndrome: The current evidences of diagnosis and management. J Arrhythm 2020; 36:962-966. [PMID: 33335610 PMCID: PMC7733558 DOI: 10.1002/joa3.12439] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/29/2020] [Accepted: 09/15/2020] [Indexed: 12/02/2022] Open
Abstract
There are many cardiac arrhythmias and sudden cardiac death (SCD) related to channelopathies or ion channel disorders. Short QT syndrome (SQTS) is an inherited cardiac channelopathy principally caused by defective functioning of both potassium-calcium ion channel that lead to abnormal shortening of QT interval, and an increased risk of ventricular and atrial arrhythmias. Tall T waves in all lead electrocardiogram (ECG), peaked T waves, and narrow-based T waves that are reminiscent of the typical "desert tent" T waves of hyperkalemia are frequently associated with SQTS. Diagnosis is based on patient's family history, evaluation of symptoms (palpitations and cardiac arrest), and 12-lead ECG. It can be time challenging because of the wide range of QT interval in healthy subjects. Implantable cardioverter defibrillator (ICD) is the first-line therapy in SQTS. Quinidine has the potential to be an effective pharmacological therapy for SQTS patients, especially in young children who are not feasible in ICD implantation, because of the ability to prolong QT interval.
Collapse
Affiliation(s)
- Ivana P. Dewi
- Faculty of MedicineUniversitas AirlanggaSurabayaIndonesia
- Faculty of MedicineDuta Wacana Christian UniversityYogyakartaIndonesia
- Department of Cardiology and Vascular MedicineDr. Soetomo General HospitalSurabayaIndonesia
| | - Budi B. Dharmadjati
- Faculty of MedicineUniversitas AirlanggaSurabayaIndonesia
- Department of Cardiology and Vascular MedicineDr. Soetomo General HospitalSurabayaIndonesia
| |
Collapse
|
12
|
Endres D, Decher N, Röhr I, Vowinkel K, Domschke K, Komlosi K, Tzschach A, Gläser B, Schiele MA, Runge K, Süß P, Schuchardt F, Nickel K, Stallmeyer B, Rinné S, Schulze-Bahr E, Tebartz van Elst L. New Cav1.2 Channelopathy with High-Functioning Autism, Affective Disorder, Severe Dental Enamel Defects, a Short QT Interval, and a Novel CACNA1C Loss-Of-Function Mutation. Int J Mol Sci 2020; 21:ijms21228611. [PMID: 33203140 PMCID: PMC7696251 DOI: 10.3390/ijms21228611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 11/04/2020] [Accepted: 11/07/2020] [Indexed: 12/12/2022] Open
Abstract
Complex neuropsychiatric-cardiac syndromes can be genetically determined. For the first time, the authors present a syndromal form of short QT syndrome in a 34-year-old German male patient with extracardiac features with predominant psychiatric manifestation, namely a severe form of secondary high-functioning autism spectrum disorder (ASD), along with affective and psychotic exacerbations, and severe dental enamel defects (with rapid wearing off his teeth) due to a heterozygous loss-of-function mutation in the CACNA1C gene (NM_000719.6: c.2399A > C; p.Lys800Thr). This mutation was found only once in control databases; the mutated lysine is located in the Cav1.2 calcium channel, is highly conserved during evolution, and is predicted to affect protein function by most pathogenicity prediction algorithms. L-type Cav1.2 calcium channels are widely expressed in the brain and heart. In the case presented, electrophysiological studies revealed a prominent reduction in the current amplitude without changes in the gating behavior of the Cav1.2 channel, most likely due to a trafficking defect. Due to the demonstrated loss of function, the p.Lys800Thr variant was finally classified as pathogenic (ACMG class 4 variant) and is likely to cause a newly described Cav1.2 channelopathy.
Collapse
Affiliation(s)
- Dominique Endres
- Section for Experimental Neuropsychiatry, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.R.); (K.N.); (L.T.v.E.)
- Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.D.); (M.A.S.)
- Correspondence: ; Tel.: +49-761-270-66360
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior-Philipps-University Marburg, 35037 Marburg, Germany; (N.D.); (I.R.); (K.V.); (S.R.)
| | - Isabell Röhr
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior-Philipps-University Marburg, 35037 Marburg, Germany; (N.D.); (I.R.); (K.V.); (S.R.)
| | - Kirsty Vowinkel
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior-Philipps-University Marburg, 35037 Marburg, Germany; (N.D.); (I.R.); (K.V.); (S.R.)
| | - Katharina Domschke
- Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.D.); (M.A.S.)
- Center for Basics in Neuromodulation, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Katalin Komlosi
- Institute of Human Genetics, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; (K.K.); (A.T.); (B.G.)
| | - Andreas Tzschach
- Institute of Human Genetics, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; (K.K.); (A.T.); (B.G.)
| | - Birgitta Gläser
- Institute of Human Genetics, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; (K.K.); (A.T.); (B.G.)
| | - Miriam A. Schiele
- Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.D.); (M.A.S.)
| | - Kimon Runge
- Section for Experimental Neuropsychiatry, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.R.); (K.N.); (L.T.v.E.)
- Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.D.); (M.A.S.)
| | - Patrick Süß
- Department of Molecular Neurology, University Hospital Erlangen, 91054 Erlangen, Germany;
| | - Florian Schuchardt
- Department of Neurology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany;
| | - Kathrin Nickel
- Section for Experimental Neuropsychiatry, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.R.); (K.N.); (L.T.v.E.)
- Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.D.); (M.A.S.)
| | - Birgit Stallmeyer
- Institute for Genetics of Heart Diseases, Department of Cardiovascular Medicine, University Hospital Münster, 48149 Münster, Germany; (B.S.); (E.S.-B.)
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior-Philipps-University Marburg, 35037 Marburg, Germany; (N.D.); (I.R.); (K.V.); (S.R.)
| | - Eric Schulze-Bahr
- Institute for Genetics of Heart Diseases, Department of Cardiovascular Medicine, University Hospital Münster, 48149 Münster, Germany; (B.S.); (E.S.-B.)
| | - Ludger Tebartz van Elst
- Section for Experimental Neuropsychiatry, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.R.); (K.N.); (L.T.v.E.)
- Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (K.D.); (M.A.S.)
| |
Collapse
|
13
|
Lan H, Xu Q, El-Battrawy I, Zhong R, Li X, Lang S, Cyganek L, Borggrefe M, Zhou X, Akin I. Ionic Mechanisms of Disopyramide Prolonging Action Potential Duration in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes From a Patient With Short QT Syndrome Type 1. Front Pharmacol 2020; 11:554422. [PMID: 33154722 PMCID: PMC7586889 DOI: 10.3389/fphar.2020.554422] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 09/16/2020] [Indexed: 11/29/2022] Open
Abstract
Short QT syndrome (SQTS) is associated with tachyarrhythmias and sudden cardiac death. So far, only quinidine has been demonstrated to be effective in patients with SQTS type 1(SQTS1). The aim of this study was to investigate the mechanisms of disopyramide underlying its antiarrhythmic effects in SQTS1 with the N588K mutation in HERG channel. Human-induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) from a patient with SQTS1 and a healthy donor, patch clamp, and calcium imaging measurements were employed to assess the drug effects. Disopyramide prolonged the action potential duration (APD) in hiPSC-CMs from a SQTS1-patient (SQTS1-hiPSC-CMs). In spontaneously beating SQTS1-hiPSC-CMs challenged by carbachol plus epinephrine, disopyramide reduced the arrhythmic events. Disopyramide enhanced the inward L-type calcium channel current (ICa-L), the late sodium channel current (late INa) and the Na/Ca exchanger current (INCX), but it reduced the outward small-conductance calcium-activated potassium channel current (ISK), leading to APD-prolongation. Disopyramide displayed no effects on the rapidly and slowly activating delayed rectifier and ATP-sensitive potassium channel currents. In hiPSC-CMs from the healthy donor, disopyramide reduced peak INa, ICa-L, IKr, and ISK but enhanced late INa and INCX. The results demonstrated that disopyramide may be effective for preventing tachyarrhythmias in SQTS1-patients carrying the N588K mutation in HERG channel by APD-prolongation via enhancing ICa-L, late INa, INCX, and reducing ISK.
Collapse
Affiliation(s)
- Huan Lan
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Qiang Xu
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,Department of Histology and Embryology, Southwest Medical University, Luzhou, China
| | - Ibrahim El-Battrawy
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Mannheim, Germany
| | - Rujia Zhong
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Xin Li
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Siegfried Lang
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Mannheim, Germany
| | - Lukas Cyganek
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.,Stem Cell Unit, Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Martin Borggrefe
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Mannheim, Germany
| | - Xiaobo Zhou
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China.,First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Mannheim, Germany
| | - Ibrahim Akin
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg-Mannheim, Mannheim, Germany
| |
Collapse
|
14
|
Abstract
Short QT syndrome is a malignant repolarisation disorder characterised by short QT intervals. We present a previously asymptomatic 14-year-old male patient with negative family history, who suffered a sudden cardiac arrest while playing basketball and diagnosed with short QT syndrome to make emphasis on the fact that although very rare patients with this syndrome may experience cardiac arrest during exercise.
Collapse
|
15
|
Boutjdir M, Lazzerini PE. A Novel Peptide/Antibody-Based Antiarrhythmic Approach to Long QT Syndrome and Beyond. J Am Coll Cardiol 2020; 75:2153-2155. [PMID: 32354383 DOI: 10.1016/j.jacc.2020.03.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/13/2020] [Accepted: 03/17/2020] [Indexed: 01/08/2023]
Affiliation(s)
- Mohamed Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, New York; Departments of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Medical Center, New York, New York; Cardiology Division, Department of Medicine, NYU School of Medicine, New York, New York.
| | - Pietro Enea Lazzerini
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| |
Collapse
|
16
|
Shinnawi R, Shaheen N, Huber I, Shiti A, Arbel G, Gepstein A, Ballan N, Setter N, Tijsen AJ, Borggrefe M, Gepstein L. Modeling Reentry in the Short QT Syndrome With Human-Induced Pluripotent Stem Cell-Derived Cardiac Cell Sheets. J Am Coll Cardiol 2019; 73:2310-24. [PMID: 31072576 DOI: 10.1016/j.jacc.2019.02.055] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 12/30/2018] [Accepted: 02/04/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND The short QT syndrome (SQTS) is an inherited arrhythmogenic syndrome characterized by abnormal ion channel function, life-threatening arrhythmias, and sudden cardiac death. OBJECTIVES The purpose of this study was to establish a patient-specific human-induced pluripotent stem cell (hiPSC) model of the SQTS, and to provide mechanistic insights into its pathophysiology and therapy. METHODS Patient-specific hiPSCs were generated from a symptomatic SQTS patient carrying the N588K mutation in the KCNH2 gene, differentiated into cardiomyocytes, and compared with healthy and isogenic (established by CRISPR/Cas9-based mutation correction) control hiPSC-derived cardiomyocytes (hiPSC-CMs). Patch-clamp was used to evaluate action-potential (AP) and IKr current properties at the cellular level. Conduction and arrhythmogenesis were studied at the tissue level using confluent 2-dimensional hiPSC-derived cardiac cell sheets (hiPSC-CCSs) and optical mapping. RESULTS Intracellular recordings demonstrated shortened action-potential duration (APD) and abbreviated refractory period in the SQTS-hiPSC-CMs. Similarly, voltage- and AP-clamp recordings revealed increased IKr current density due to attenuated inactivation, primarily in the AP plateau phase. Optical mapping of the SQTS-hiPSC-CCSs revealed shortened APD, impaired APD-rate adaptation, abbreviated wavelength of excitation, and increased inducibility of sustained spiral waves. Phase-mapping analysis revealed accelerated and stabilized rotors manifested by increased rotor rotation frequency, increased rotor curvature, decreased core meandering, and increased rotor complexity. Application of quinidine and disopyramide, but not sotalol, normalized APD and suppressed arrhythmia induction. CONCLUSIONS A novel hiPSC-based model of the SQTS was established at both the cellular and tissue levels. This model recapitulated the disease phenotype in the culture dish and provided important mechanistic insights into arrhythmia mechanisms in the SQTS and its treatment.
Collapse
|
17
|
|
18
|
Abstract
The human voltage-sensitive K+ channel hERG plays a fundamental role in cardiac action potential repolarization, effectively controlling the QT interval of the electrocardiogram. Inherited loss- or gain-of-function mutations in hERG can result in dangerous “long” (LQTS) or “short” QT syndromes (SQTS), respectively, and the anomalous susceptibility of hERG to block by a diverse range of drugs underlies an acquired LQTS. A recent open channel cryo-EM structure of hERG should greatly advance understanding of the molecular basis of hERG channelopathies and drug-induced LQTS. Here we describe an update of recent research that addresses the nature of the particular gated state of hERG captured in the new structure, and the insight afforded by the structure into the molecular basis for high affinity drug block of hERG, the binding of hERG activators and the molecular basis of hERG's peculiar gating properties. Interpretation of the pharmacology of natural SQTS mutants in the context of the structure is a promising approach to understanding the molecular basis of hERG inactivation, and the structure suggests how voltage-dependent changes in the membrane domain may be transmitted to an extracellular “turret” to effect inactivation through aromatic side chain motifs that are conserved throughout the KCNH family of channels.
Collapse
Affiliation(s)
- Andrew Butler
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, Bristol, United Kingdom
| | - Matthew V Helliwell
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, Bristol, United Kingdom
| | - Yihong Zhang
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, Bristol, United Kingdom
| | - Jules C Hancox
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, Bristol, United Kingdom
| | | |
Collapse
|
19
|
Raschwitz LS, El-Battrawy I, Schlentrich K, Besler J, Veith M, Roterberg G, Liebe V, Schimpf R, Lang S, Wolpert C, Zhou X, Akin I, Borggrefe M. Differences in Short QT Syndrome Subtypes: A Systematic Literature Review and Pooled Analysis. Front Genet 2020; 10:1312. [PMID: 32010184 PMCID: PMC6979065 DOI: 10.3389/fgene.2019.01312] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/29/2019] [Indexed: 12/20/2022] Open
Abstract
Background Short QT syndrome (SQTS) is a rare syndrome and affects different types of genes. However, data on differences of clinical profile and outcome of different SQTS types are sparse. Methods We conducted a pooled analysis of 110 SQTS patients. Patients have been diagnosed between 2000 and 2017 at our institution (n = 12) and revealed using a literature review (n = 98). 29 studies were identified by analysing systematic data bases (PubMed, Web of Science, Cochrane Libary, Cinahl). Results 67 patients with genotype positive SQTS origin and 43 patients with genotype negative origin were found. A significant difference is documented between the sex with a higher predominance of male in genotype negative SQTS patients and predominance of females in genotype positive SQTS patients (male 52% versus 84%, female 45% versus 14%; p = 0.0016). No relevant difference of their median age (genotype positive 27 ± 19 versus genotype negative 29 ± 15; p = 0.48) was found. Asymptomatic patients and patients reporting symptoms such as syncope, sudden cardiac death, atrial flutter and ventricular fibrillation documented in both groups were similar except atrial fibrillation (genotype positive 19% versus genotype negative 0%; p = 0.0055). The QTc interval was not significantly different in both groups (genotype positive 315 ± 32 versus genotype negative 320 ± 19; p = 0.30). The treatments (medical treatment and ICD implantation) in both groups were comparable. Electrophysiology studies were not significantly higher documented in patients with genotype positive and negative origin (24% versus 9%; p = 0.075). Events at follow up such as VT, VF, and SCD were not higher presented in patients with genotype positive (13% versus 9%) (p = 0.25). 54% of genotype positive SQTS patients showed SQTS 1 followed by STQS 2 (21%) and SQTS 3 (10%). Conclusions The long-term risk of a malignant arrhythmic event is not higher in patients with genotype positive. However, patients with genotype positive present themselves more often with AF with a female predominance. Also, other events at follow up such as syncope, atrial flutter and palpitation were not significantly higher (9% versus 0%; p = 0.079).
Collapse
Affiliation(s)
- Laura S Raschwitz
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Ibrahim El-Battrawy
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Mannheim, Germany
| | - Kim Schlentrich
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Johanna Besler
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Michael Veith
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Gretje Roterberg
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Volker Liebe
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Rainer Schimpf
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Siegfried Lang
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Mannheim, Germany
| | - Christian Wolpert
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Xiaobo Zhou
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Mannheim, Germany
| | - Ibrahim Akin
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Mannheim, Germany
| | - Martin Borggrefe
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Mannheim, Germany
| |
Collapse
|
20
|
El-Battrawy I, Besler J, Li X, Lan H, Zhao Z, Liebe V, Schimpf R, Lang S, Wolpert C, Zhou X, Akin I, Borggrefe M. Impact of Antiarrhythmic Drugs on the Outcome of Short QT Syndrome. Front Pharmacol 2019; 10:771. [PMID: 31427960 PMCID: PMC6688193 DOI: 10.3389/fphar.2019.00771] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/14/2019] [Indexed: 11/22/2022] Open
Abstract
Short QT syndrome (SQTS) is associated with sudden cardiac arrest. There are limited data on the impact of antiarrhythmic drugs on the outcome of SQTS. Materials and Methods: We studied data that describe the clinical outcome of 62 SQTS patients treated with antiarrhythmic drugs, who were recruited from a pool of patients diagnosed in our institution and also from known databases after a systematic search of the published literature. Results: Sixty-two SQTS patients treated with antiarrhythmic drugs were followed up over a median timeframe of 5.6 years (interquartile range 1.6–7.7 years). Six patients, in particular, received multiple drugs as a combination. Of the 55 patients treated with hydroquinidine (HQ), long-term prophylaxis was documented in 41 patients. Fourteen patients stopped treatment due to the following reasons: gastrointestinal intolerance (n = 4), poor compliance (n = 8), and no QTc prolongation (n = 2). Of the 41 patients treated with HQ, the QTc interval increased from 313.5 ± 17.2 to 380.1 ± 21.2 ms. Thirteen of the 41 patients suffered from at least one or more ventricular tachyarrhythmias (VAs) before HQ initiation. VAs are reduced in incidence after HQ treatment (13/41: 31% versus 3/41: 7.3%, p < 0.001). Conclusion: HQ increases the corrected QT interval and prevents VAs in the majority of the patients in this cohort. HQ is safe for use in SQTS patients, particularly due to its low rate of side effects. Other antiarrhythmic drugs might be useful, but the data justifying their use are sparse.
Collapse
Affiliation(s)
- Ibrahim El-Battrawy
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - Johanna Besler
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Xin Li
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - Huan Lan
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - Zhihan Zhao
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - Volker Liebe
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Rainer Schimpf
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Siegfried Lang
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - Christian Wolpert
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Xiaobo Zhou
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - Ibrahim Akin
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - Martin Borggrefe
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| |
Collapse
|
21
|
Campuzano O, Fernandez-Falgueras A, Lemus X, Sarquella-Brugada G, Cesar S, Coll M, Mates J, Arbelo E, Jordà P, Perez-Serra A, Del Olmo B, Ferrer-Costa C, Iglesias A, Fiol V, Puigmulé M, Lopez L, Pico F, Brugada J, Brugada R. Short QT Syndrome: A Comprehensive Genetic Interpretation and Clinical Translation of Rare Variants. J Clin Med 2019; 8:jcm8071035. [PMID: 31315195 PMCID: PMC6678338 DOI: 10.3390/jcm8071035] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 12/14/2022] Open
Abstract
Short QT syndrome, one of the most lethal entities associated with sudden cardiac death, is a rare genetic disease characterized by short QT intervals detected by electrocardiogram. Several genetic variants are causally linked to the disease, but there has yet to be a comprehensive analysis of variants among patients with short QT syndrome. To fill this gap, we performed an exhaustive study of variants currently catalogued as deleterious in short QT syndrome according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Analysis of the 32 variants described in the literature determined that only nine (28.12%) have a conclusive pathogenic role. All definitively pathogenic variants are located in KCNQ1, KCNH2, or KCNJ2; three genes encoding potassium channels. Other variants located in genes encoding calcium or sodium channels are associated with electrical alterations concomitant with shortened QT intervals but do not guarantee a diagnosis of short QT syndrome. We recommend caution regarding previously reported variants classified as pathogenic. An exhaustive re-analysis is necessary to clarify the role of each variant before routinely translating genetic findings to the clinical setting.
Collapse
Affiliation(s)
- Oscar Campuzano
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain.
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain.
- Medical Science Department, School of Medicine, University of Girona, 17071 Girona, Spain.
- Biochemistry and Molecular Genetics Department, Hospital Clinic, IDIBAPS, 08036 Barcelona, Spain.
| | | | - Ximena Lemus
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Georgia Sarquella-Brugada
- Medical Science Department, School of Medicine, University of Girona, 17071 Girona, Spain
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain
| | - Sergi Cesar
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain
| | - Monica Coll
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Jesus Mates
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Elena Arbelo
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Arrhythmias Unit, Hospital Clinic, University of Barcelona, 08036 Barcelona, Spain
| | - Paloma Jordà
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Arrhythmias Unit, Hospital Clinic, University of Barcelona, 08036 Barcelona, Spain
| | | | - Bernat Del Olmo
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Carles Ferrer-Costa
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Anna Iglesias
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Victoria Fiol
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain
| | - Marta Puigmulé
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Laura Lopez
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Ferran Pico
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Josep Brugada
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain
- Arrhythmias Unit, Hospital Clinic, University of Barcelona, 08036 Barcelona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain.
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain.
- Medical Science Department, School of Medicine, University of Girona, 17071 Girona, Spain.
- Cardiology Service, Hospital Josep Trueta, University of Girona, 17007 Girona, Spain.
| |
Collapse
|
22
|
Abstract
Over the past two decades, our understanding of inherited primary arrhythmia syndromes has been enriched by studies that have aimed to define the clinical characteristics and the genetic, cellular and molecular features predisposing patients to an enhanced risk of ventricular arrhythmias. In contrast, very little is known about the causative role of inherited cardiac channelopathies on atrial conduction abnormalities possibly leading to different atrial tachyarrhythmias. The diagnostic and therapeutic management of patients with an inherited cardiac channelopathy presenting with atrial arrhythmias remains highly challenging and is in urgent need of improvement. This review will assess the current knowledge on atrial electrical abnormalities affecting patients with different forms of inherited primary arrhythmia syndromes, including long and short QT syndromes, early repolarisation syndrome, catecholaminergic polymorphic ventricular tachycardia and Brugada syndrome.
Collapse
Affiliation(s)
- Giulio Conte
- Division of Cardiology, Cardiocentro Ticino Lugano, Switzerland.,Centre for Computational Medicine in Cardiology, Faculty of Informatics, Università della Svizzera Italiana Lugano, Switzerland
| | - Ulrich Schotten
- Department of Physiology Cardiovascular Research Institute Maastricht Maastricht, the Netherlands
| | - Angelo Auricchio
- Division of Cardiology, Cardiocentro Ticino Lugano, Switzerland.,Centre for Computational Medicine in Cardiology, Faculty of Informatics, Università della Svizzera Italiana Lugano, Switzerland
| |
Collapse
|
23
|
Lester RM, Paglialunga S, Johnson IA. QT Assessment in Early Drug Development: The Long and the Short of It. Int J Mol Sci 2019; 20:ijms20061324. [PMID: 30884748 PMCID: PMC6471571 DOI: 10.3390/ijms20061324] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/01/2019] [Accepted: 03/05/2019] [Indexed: 11/16/2022] Open
Abstract
The QT interval occupies a pivotal role in drug development as a surface biomarker of ventricular repolarization. The electrophysiologic substrate for QT prolongation coupled with reports of non-cardiac drugs producing lethal arrhythmias captured worldwide attention from government regulators eventuating in a series of guidance documents that require virtually all new chemical compounds to undergo rigorous preclinical and clinical testing to profile their QT liability. While prolongation or shortening of the QT interval may herald the appearance of serious cardiac arrhythmias, the positive predictive value of an abnormal QT measurement for these arrhythmias is modest, especially in the absence of confounding clinical features or a congenital predisposition that increases the risk of syncope and sudden death. Consequently, there has been a paradigm shift to assess a compound's cardiac risk of arrhythmias centered on a mechanistic approach to arrhythmogenesis rather than focusing solely on the QT interval. This entails both robust preclinical and clinical assays along with the emergence of concentration QT modeling as a primary analysis tool to determine whether delayed ventricular repolarization is present. The purpose of this review is to provide a comprehensive understanding of the QT interval and highlight its central role in early drug development.
Collapse
Affiliation(s)
- Robert M Lester
- Cardiac Safety Services, Celerion, 2420 W Baseline Rd, Tempe, AZ 85283, USA.
| | | | - Ian A Johnson
- Cardiac Safety Services, Celerion, 2420 W Baseline Rd, Tempe, AZ 85283, USA.
| |
Collapse
|
24
|
Whittaker DG, Hancox JC, Zhang H. In silico Assessment of Pharmacotherapy for Human Atrial Patho-Electrophysiology Associated With hERG-Linked Short QT Syndrome. Front Physiol 2019; 9:1888. [PMID: 30687112 PMCID: PMC6336736 DOI: 10.3389/fphys.2018.01888] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 12/12/2018] [Indexed: 12/19/2022] Open
Abstract
Short QT syndrome variant 1 (SQT1) arises due to gain-of-function mutations to the human Ether-à-go-go-Related Gene (hERG), which encodes the α subunit of channels carrying rapid delayed rectifier potassium current, IKr. In addition to QT interval shortening and ventricular arrhythmias, SQT1 is associated with increased risk of atrial fibrillation (AF), which is often the only clinical presentation. However, the underlying basis of AF and its pharmacological treatment remain incompletely understood in the context of SQT1. In this study, computational modeling was used to investigate mechanisms of human atrial arrhythmogenesis consequent to a SQT1 mutation, as well as pharmacotherapeutic effects of selected class I drugs–disopyramide, quinidine, and propafenone. A Markov chain formulation describing wild type (WT) and N588K-hERG mutant IKr was incorporated into a contemporary human atrial action potential (AP) model, which was integrated into one-dimensional (1D) tissue strands, idealized 2D sheets, and a 3D heterogeneous, anatomical human atria model. Multi-channel pharmacological effects of disopyramide, quinidine, and propafenone, including binding kinetics for IKr/hERG and sodium current, INa, were considered. Heterozygous and homozygous formulations of the N588K-hERG mutation shortened the AP duration (APD) by 53 and 86 ms, respectively, which abbreviated the effective refractory period (ERP) and excitation wavelength in tissue, increasing the lifespan and dominant frequency (DF) of scroll waves in the 3D anatomical human atria. At the concentrations tested in this study, quinidine most effectively prolonged the APD and ERP in the setting of SQT1, followed by disopyramide and propafenone. In 2D simulations, disopyramide and quinidine promoted re-entry termination by increasing the re-entry wavelength, whereas propafenone induced secondary waves which destabilized the re-entrant circuit. In 3D simulations, the DF of re-entry was reduced in a dose-dependent manner for disopyramide and quinidine, and propafenone to a lesser extent. All of the anti-arrhythmic agents promoted pharmacological conversion, most frequently terminating re-entry in the order quinidine > propafenone = disopyramide. Our findings provide further insight into mechanisms of SQT1-related AF and a rational basis for the pursuit of combined IKr and INa block based pharmacological strategies in the treatment of SQT1-linked AF.
Collapse
Affiliation(s)
- Dominic G Whittaker
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom.,Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Jules C Hancox
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,Cardiovascular Research Laboratories, Department of Physiology, Pharmacology and Neuroscience, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.,Space Institute of Southern China, Shenzhen, China.,Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| |
Collapse
|
25
|
Campuzano O, Sarquella-Brugada G, Cesar S, Arbelo E, Brugada J, Brugada R. Recent Advances in Short QT Syndrome. Front Cardiovasc Med 2018; 5:149. [PMID: 30420954 PMCID: PMC6215807 DOI: 10.3389/fcvm.2018.00149] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 10/03/2018] [Indexed: 01/22/2023] Open
Abstract
Short QT syndrome is a highly malignant inherited cardiac disease characterized by ventricular tachyarrhythmias leading to syncope and sudden cardiac death. It is responsible of lethal episodes in young people, mainly infants. International guidelines establish diagnostic criteria with the presence of a QTc ≤ 340 ms in the electrocardiogram despite clinical diagnostic values remain controversial. In last years, clinical diagnosis, risk stratification as well as preventive therapies have been improved due to identification of pathophysiological mechanisms. The only effective option is implantation of a defibrillator despite Quinidine may be at times an effective option. Currently, a limited number of rare variants have been identified in seven genes, which account for nearly 20–30% of families. However, some of these variants are associated with phenotypes showing a shorter QT interval but no conclusive diagnosis of Short QT syndrome. Therefore, an exhaustive interpretation of each variant and a close genotype-phenotype correlation is necessary before clinical translation. Here, we review the main clinical and genetic hallmarks of this rare entity.
Collapse
Affiliation(s)
- Oscar Campuzano
- Medical Science Department, University of Girona, Girona, Spain.,Cardiovascular Genetics Center, IDIBGI, Girona, Spain.,Centro Investigación Biomédica Red Enfermedades Cardiovasculares, Madrid, Spain
| | - Georgia Sarquella-Brugada
- Medical Science Department, University of Girona, Girona, Spain.,Pediatric Arrhythmia Unit, Cardiology Department, Hospital Sant Joan de Déu Barcelona, Barcelona, Spain
| | - Sergi Cesar
- Pediatric Arrhythmia Unit, Cardiology Department, Hospital Sant Joan de Déu Barcelona, Barcelona, Spain
| | - Elena Arbelo
- Centro Investigación Biomédica Red Enfermedades Cardiovasculares, Madrid, Spain.,Institut Clínic Cardiovascular, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Josep Brugada
- Centro Investigación Biomédica Red Enfermedades Cardiovasculares, Madrid, Spain.,Pediatric Arrhythmia Unit, Cardiology Department, Hospital Sant Joan de Déu Barcelona, Barcelona, Spain.,Institut Clínic Cardiovascular, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Ramon Brugada
- Medical Science Department, University of Girona, Girona, Spain.,Cardiovascular Genetics Center, IDIBGI, Girona, Spain.,Pediatric Arrhythmia Unit, Cardiology Department, Hospital Sant Joan de Déu Barcelona, Barcelona, Spain.,Familial Cardiomyopathies Unit, Hospital Universitari de Girona Doctor Josep Trueta, Girona, Spain
| |
Collapse
|
26
|
Whittaker DG, Colman MA, Ni H, Hancox JC, Zhang H. Human Atrial Arrhythmogenesis and Sinus Bradycardia in KCNQ1-Linked Short QT Syndrome: Insights From Computational Modelling. Front Physiol 2018; 9:1402. [PMID: 30337886 PMCID: PMC6180159 DOI: 10.3389/fphys.2018.01402] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/14/2018] [Indexed: 11/25/2022] Open
Abstract
Atrial fibrillation (AF) and sinus bradycardia have been reported in patients with short QT syndrome variant 2 (SQT2), which is underlain by gain-of-function mutations in KCNQ1 encoding the α subunit of channels carrying slow delayed rectifier potassium current, IKs. However, the mechanism(s) underlying the increased atrial arrhythmogenesis and impaired cardiac pacemaking activity arising from increased IKs remain unclear. Possible pharmacological interventions of AF in the SQT2 condition also remain to be elucidated. Using computational modelling, we assessed the functional impact of SQT2 mutations on human sinoatrial node (SAN) pacemaking, atrial repolarisation and arrhythmogenesis, and efficacy of the anti-arrhythmic drug quinidine. Markov chain formulations of IKs describing two KCNQ1 mutations – V141M and V307L – were developed from voltage-clamp experimental data and then incorporated into contemporary action potential (AP) models of human atrial and SAN cells, the former of which were integrated into idealised and anatomically detailed tissue models. Both mutations shortened atrial AP duration (APD) through distinct IKs ‘gain-of-function’ mechanisms, whereas SAN pacemaking rate was slowed markedly only by the V141M mutation. Differences in APD restitution steepness influenced re-entry dynamics in tissue – the V141M mutation promoted stationary and stable spiral waves whereas the V307L mutation promoted non-stationary and unstable re-entrant waves. Both mutations shortened tissue excitation wavelength through reduced effective refractory period but not conduction velocity, which served to increase the lifespan of re-entrant excitation in a 3D anatomical human atria model, as well as the dominant frequency (DF), which was higher for the V141M mutation. Quinidine was effective at terminating arrhythmic excitation waves associated with the V307L but not V141M mutation, and reduced the DF in a dose-dependent manner under both mutation conditions. This study provides mechanistic insights into different AF/bradycardia phenotypes in SQT2 and the efficacy of quinidine pharmacotherapy.
Collapse
Affiliation(s)
- Dominic G Whittaker
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.,Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Michael A Colman
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Haibo Ni
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Jules C Hancox
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,School of Physiology, Pharmacology and Neuroscience, and Cardiovascular Research Laboratories, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.,Space Institute of Southern China, Shenzhen, China.,Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease/Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| |
Collapse
|
27
|
Butler A, Zhang Y, Stuart AG, Dempsey CE, Hancox JC. Action potential clamp characterization of the S631A hERG mutation associated with short QT syndrome. Physiol Rep 2018; 6:e13845. [PMID: 30175559 PMCID: PMC6119704 DOI: 10.14814/phy2.13845] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/30/2018] [Accepted: 08/02/2018] [Indexed: 11/27/2022] Open
Abstract
The hERG potassium channel is critical to normal repolarization of cardiac action potentials (APs) and loss- and gain-of-function hERG mutations are associated, respectively, with long and short QT syndromes, pathological conditions that can lead to arrhythmias and sudden death. hERG current (IhERG ) exhibits uniquely fast inactivation involving conformational changes to the channel pore. The S631A hERG pore mutation was originally engineered to interrogate hERG channel inactivation, but has very recently been found in a family with short QT syndrome (SQTS). Accordingly, this study characterized the effects of the S631A mutation on IhERG profile during ventricular, atrial, and Purkinje fiber (PF) AP waveforms, using patch clamp recording from hERG expressing HEK 293 cells at 37°C. Under conventional voltage clamp, the current-voltage (I-V) relation for IhERG exhibited a marked right-ward shift in the region of negative slope at positive membrane potentials. Under ventricular AP clamp, the S631A mutation resulted in augmented IhERG , which also peaked much earlier during the AP plateau than did wild-type (WT) IhERG . Instantaneous I-V relations showed a marked positive shift in peak repolarizing current during the ventricular AP in the S631A setting, while the instantaneous conductance-voltage relation showed an earlier and more sustained rise in S631A compared to WT IhERG conductance during ventricular repolarization. Experiments with atrial and PF APs in each case also showed augmented and positively shifted IhERG in the S631A setting, indicating that the S631A mutation is likely to accelerate repolarization in all three cardiac regions. Ventricular AP clamp experiments showed retained effectiveness of the class Ia antiarrhythmic drug quinidine (1 μmol/L) against S631A IhERG . Quinidine is thus likely to be effective in reducing excessively fast repolarization in SQTS resulting from the S631A hERG mutation.
Collapse
Affiliation(s)
- Andrew Butler
- School of PhysiologyPharmacology and NeuroscienceMedical Sciences BuildingUniversity WalkBristolUnited Kingdom
| | - Yihong Zhang
- School of PhysiologyPharmacology and NeuroscienceMedical Sciences BuildingUniversity WalkBristolUnited Kingdom
| | - Alan G. Stuart
- Bristol Heart InstituteUniversity of BristolBristolUnited Kingdom
| | | | - Jules C. Hancox
- School of PhysiologyPharmacology and NeuroscienceMedical Sciences BuildingUniversity WalkBristolUnited Kingdom
- Bristol Heart InstituteUniversity of BristolBristolUnited Kingdom
| |
Collapse
|
28
|
El-Battrawy I, Lan H, Cyganek L, Zhao Z, Li X, Buljubasic F, Lang S, Yücel G, Sattler K, Zimmermann WH, Utikal J, Wieland T, Ravens U, Borggrefe M, Zhou XB, Akin I. Modeling Short QT Syndrome Using Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes. J Am Heart Assoc 2018; 7:e007394. [PMID: 29574456 PMCID: PMC5907581 DOI: 10.1161/jaha.117.007394] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 01/26/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND Short QT syndrome (SQTS), a disorder associated with characteristic ECG QT-segment abbreviation, predisposes affected patients to sudden cardiac death. Despite some progress in assessing the organ-level pathophysiology and genetic changes of the disorder, the understanding of the human cellular phenotype and discovering of an optimal therapy has lagged because of a lack of appropriate human cellular models of the disorder. The objective of this study was to establish a cellular model of SQTS using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). METHODS AND RESULTS This study recruited 1 patient with short QT syndrome type 1 carrying a mutation (N588K) in KCNH2 as well as 2 healthy control subjects. We generated hiPSCs from their skin fibroblasts, and differentiated hiPSCs into cardiomyocytes (hiPSC-CMs) for physiological and pharmacological studies. The hiPSC-CMs from the patient showed increased rapidly activating delayed rectifier potassium channel current (IKr) density and shortened action potential duration compared with healthy control hiPSC-CMs. Furthermore, they demonstrated abnormal calcium transients and rhythmic activities. Carbachol increased the arrhythmic events in SQTS but not in control cells. Gene and protein expression profiling showed increased KCNH2 expression in SQTS cells. Quinidine but not sotalol or metoprolol prolonged the action potential duration and abolished arrhythmic activity induced by carbachol. CONCLUSIONS Patient-specific hiPSC-CMs are able to recapitulate single-cell phenotype features of SQTS and provide novel opportunities to further elucidate the cellular disease mechanism and test drug effects.
Collapse
MESH Headings
- Action Potentials/drug effects
- Adult
- Anti-Arrhythmia Agents/pharmacology
- Arrhythmias, Cardiac/drug therapy
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/physiopathology
- Calcium Signaling
- Case-Control Studies
- Cell Differentiation
- Cell Lineage
- Cells, Cultured
- ERG1 Potassium Channel/genetics
- ERG1 Potassium Channel/metabolism
- Genetic Predisposition to Disease
- Heart Conduction System/abnormalities
- Heart Conduction System/metabolism
- Heart Conduction System/physiopathology
- Heart Defects, Congenital/drug therapy
- Heart Defects, Congenital/genetics
- Heart Defects, Congenital/metabolism
- Heart Defects, Congenital/physiopathology
- Heart Rate
- Humans
- Induced Pluripotent Stem Cells/drug effects
- Induced Pluripotent Stem Cells/metabolism
- Kinetics
- Male
- Mutation, Missense
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Phenotype
Collapse
Affiliation(s)
- Ibrahim El-Battrawy
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Huan Lan
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Lukas Cyganek
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
- Stem Cell Unit, Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Germany
| | - Zhihan Zhao
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Xin Li
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Fanis Buljubasic
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Siegfried Lang
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Gökhan Yücel
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Katherine Sattler
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - Wolfram-Hubertus Zimmermann
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
- Institute of Pharmacology and Toxicology, University of Göttingen, Germany
| | - Jochen Utikal
- Skin Cancer Unit, German Cancer Research Center (DKFZ), Heidelberg and Department of Dermatology, Venereology and Allergology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Thomas Wieland
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Ursula Ravens
- Institute of Experimental Cardiovascular Medicine, University Heart Centre Freiburg, Bad Krozingen, Freiburg, Germany
| | - Martin Borggrefe
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| | - Xiao-Bo Zhou
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Ibrahim Akin
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
- DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen, Mannheim, Germany
| |
Collapse
|
29
|
Abstract
Short QT syndrome (SQTS) is a myocardial conduction disorder characterized by a short QT interval on electrocardiogram and predisposition to familial atrial fibrillation and/or sudden cardiac death. Genetic SQTS is primarily caused by one or more cardiac ion channelopathies, in which either impaired depolarization currents, or enhanced repolarization currents, shorten cardiac action potential duration. Given that QT interval duration is not always predictive of arrhythmia burden and risk of death in SQTS, there is a need to understand the molecular mechanisms of the condition to improve risk prognostication and potential pharmacologic treatment. In the last decade, several computational advances and in vitro preclinical studies have provided insight into the molecular mechanisms underlying congenital SQTS. In this review, we discuss recent findings in SQTS molecular mechanisms and correlate these advances with clinical guidelines for SQTS diagnosis and treatment.
Collapse
Affiliation(s)
- Srikanth Perike
- Department of Medicine, Section of Cardiology, Department of Bioengineering, Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Mark D McCAULEY
- Department of Medicine, Section of Cardiology, Department of Bioengineering, Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL
| |
Collapse
|
30
|
Abstract
Long QT syndrome, short QT syndrome, Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia are inherited primary electrical disorders that predispose to sudden cardiac death in the absence of structural heart disease. Also known as cardiac channelopathies, primary electrical disorders respond to mutations in genes encoding cardiac ion channels and/or their regulatory proteins, which result in modifications in the cardiac action potential or in the intracellular calcium handling that lead to electrical instability and life-threatening ventricular arrhythmias. These disorders may have low penetrance and expressivity, making clinical diagnosis often challenging. However, because sudden cardiac death might be the first presenting symptom of the disease, early diagnosis becomes essential. Genetic testing might be helpful in this regard, providing a definite diagnosis in some patients. Yet important limitations still exist, with a significant proportion of patients remaining with no causative mutation identifiable after genetic testing. This review aims to provide the latest knowledge on the genetic basis of cardiac channelopathies and discuss the role of the affected proteins in the pathophysiology of each one of these diseases.
Collapse
|
31
|
Whittaker DG, Ni H, Benson AP, Hancox JC, Zhang H. Computational Analysis of the Mode of Action of Disopyramide and Quinidine on hERG-Linked Short QT Syndrome in Human Ventricles. Front Physiol 2017; 8:759. [PMID: 29085299 PMCID: PMC5649182 DOI: 10.3389/fphys.2017.00759] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/19/2017] [Indexed: 01/24/2023] Open
Abstract
The short QT syndrome (SQTS) is a rare cardiac disorder associated with arrhythmias and sudden death. Gain-of-function mutations to potassium channels mediating the rapid delayed rectifier current, IKr, underlie SQTS variant 1 (SQT1), in which treatment with Na+ and K+ channel blocking class Ia anti-arrhythmic agents has demonstrated some efficacy. This study used computational modeling to gain mechanistic insights into the actions of two such drugs, disopyramide and quinidine, in the setting of SQT1. The O'Hara-Rudy (ORd) human ventricle model was modified to incorporate a Markov chain formulation of IKr describing wild type (WT) and SQT1 mutant conditions. Effects of multi-channel block by disopyramide and quinidine, including binding kinetics and altered potency of IKr/hERG channel block in SQT1 and state-dependent block of sodium channels, were simulated on action potential and multicellular tissue models. A one-dimensional (1D) transmural ventricular strand model was used to assess prolongation of the QT interval, effective refractory period (ERP), and re-entry wavelength (WL) by both drugs. Dynamics of re-entrant excitation waves were investigated using a 3D human left ventricular wedge model. In the setting of SQT1, disopyramide, and quinidine both produced a dose-dependent prolongation in (i) the QT interval, which was primarily due to IKr block, and (ii) the ERP, which was mediated by a synergistic combination of IKr and INa block. Over the same range of concentrations quinidine was more effective in restoring the QT interval, due to more potent block of IKr. Both drugs demonstrated an anti-arrhythmic increase in the WL of re-entrant circuits. In the 3D wedge, disopyramide and quinidine at clinically-relevant concentrations decreased the dominant frequency of re-entrant excitations and exhibited anti-fibrillatory effects; preventing formation of multiple, chaotic wavelets which developed in SQT1, and could terminate arrhythmias. This computational modeling study provides novel insights into the clinical efficacy of disopyramide and quinidine in the setting of SQT1; it also dissects ionic mechanisms underlying QT and ERP prolongation. Our findings show that both drugs demonstrate efficacy in reversing the SQT1 phenotype, and indicate that disopyramide warrants further investigation as an alternative to quinidine in the treatment of SQT1.
Collapse
Affiliation(s)
- Dominic G Whittaker
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Haibo Ni
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Alan P Benson
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom.,Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Jules C Hancox
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom.,School of Physiology, Pharmacology and Neuroscience, Cardiovascular Research Laboratories, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom.,School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.,Space Institute of Southern China, Shenzhen, China
| |
Collapse
|
32
|
Mazzanti A, Underwood K, Nevelev D, Kofman S, Priori SG. The new kids on the block of arrhythmogenic disorders: Short QT syndrome and early repolarization. J Cardiovasc Electrophysiol 2017; 28:1226-1236. [PMID: 28569435 DOI: 10.1111/jce.13265] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 05/10/2017] [Accepted: 05/25/2017] [Indexed: 12/20/2022]
Abstract
Short QT syndrome (SQTS) is one of the rarest inheritable cardiac channelopathies, characterized by an accelerated cardiac repolarization, which is also the substrate for the development of life-threatening ventricular arrhythmias. Up to this date, fewer than 200 SQTS cases have been reported in the literature worldwide. Patients with SQTS may experience a cardiac arrest as early as in the neonatal period or as late as 80 years old. The cumulative probability of experiencing a cardiac arrest by the fifth decade of life approaches 40%, highlighting the importance of early recognition and management. SQTS is an autosomal dominant disease with five identified causative genes, including three that encode for potassium channels (KCNH2, KCNQ1, and KCNJ2) and two that encode for subunits of the L-type calcium channels (CACNA1C and CACNB2). The term "early repolarization" (ER) has long been used to refer to a heterogeneous group of specific QRS-T junction patterns that are commonly found on the electrocardiograms of young healthy subjects. In the last decade, it has been suggested that in some individuals, the presence of ER may be associated with an increased risk of sudden cardiac death, and thus the term "early repolarization syndrome" (ERS) has progressively entered into use. Up to this point, however, whether ER constitutes a true primary arrhythmic disorder or whether it is simply a predisposing substrate that facilitates arrhythmias in the presence of other triggers remains an unresolved issue. In this review paper, we aim to integrate the current literature on SQTS and ERS. For each, we will describe the key steps that first led to the identification of the syndrome before moving into a discussion of our current understanding of each entity, including the epidemiology, genetics, diagnosis, clinical manifestations, and management.
Collapse
Affiliation(s)
| | | | | | - Shanna Kofman
- Molecular Cardiology, IRCCS ICS Maugeri, Pavia, Italy
| | - Silvia G Priori
- Molecular Cardiology, IRCCS ICS Maugeri, Pavia, Italy.,Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| |
Collapse
|
33
|
Rollin A, Gandjbakhch E, Giustetto C, Scrocco C, Fourcade C, Monteil B, Mondoly P, Cardin C, Maupain C, Gaita F, Maury P. Shortening of the Short Refractory Periods in Short QT Syndrome. J Am Heart Assoc 2017; 6:JAHA.117.005684. [PMID: 28566296 PMCID: PMC5669178 DOI: 10.1161/jaha.117.005684] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Background Diagnosis of short QT syndrome (SQTS) remains difficult in case of borderline QT values as often found in normal populations. Whether some shortening of refractory periods (RP) may help in differentiating SQTS from normal subjects is unknown. Methods and Results Atrial and right ventricular RP at the apex and right ventricular outflow tract as determined during standard electrophysiological study were compared between 16 SQTS patients (QTc 324±24 ms) and 15 controls with similar clinical characteristics (QTc 417±32 ms). Atrial RP were significantly shorter in SQTS compared with controls at 600‐ and 500‐ms basic cycle lengths. Baseline ventricular RP were significantly shorter in SQTS patients than in controls, both at the apex and right ventricular outflow tract and for any cycle length. Differences remained significant for RP of any subsequent extrastimulus at any cycle length and any pacing site. A cut‐off value of baseline RP <200 ms at the right ventricular outflow tract either at 600‐ or 500‐ms cycle length had a sensitivity of 86% and a specificity of 100% for the diagnosis of SQTS. Conclusions Patients with SQTS have shorter ventricular RP than controls, both at baseline during various cycle lengths and after premature extrastimuli. A cut‐off value of 200 ms at the right ventricular outflow tract during 600‐ and 500‐ms basic cycle length may help in detecting true SQTS from normal subjects with borderline QT values.
Collapse
Affiliation(s)
- Anne Rollin
- University Hospital Rangueil, Toulouse, France
| | | | | | - Chiara Scrocco
- Citta della Salute e della Scienza Hospital, Torino, Italy
| | | | | | | | | | | | - Fiorenzo Gaita
- Citta della Salute e della Scienza Hospital, Torino, Italy
| | | |
Collapse
|
34
|
Abstract
Ion channels in the myocardial cellular membrane are responsible for allowing the cardiac action potential. Genetic abnormalities in these channels can predispose to life-threatening arrhythmias. We discuss the basic science of the cardiac action potential; outline the different clinical entities, including information regarding overlapping diagnoses, touching upon relevant genetics, new innovations in screening, diagnosis, risk stratification, and management. The special considerations of sudden unexplained death and sudden infant death syndrome are discussed. Scientists and clinicians continue to reconcile the rapidly growing body of knowledge regarding the molecular mechanisms and genetics while continuing to improve our understanding of the various clinical entities and their diagnosis and management in clinical setting. Two separate searches were run on the National Center for Biotechnology Information's website. The first using the term cardiac channelopathies was run on the PubMed database using filters for time (published in past 5 years) and age (birth-18 years), yielding 47 results. The second search using the medical subject headings (MeSH) database with the search terms “Long QT Syndrome” (MeSH) and “Short QT Syndrome” (MeSH) and “Brugada Syndrome” (MeSH) and “Catecholaminergic Polymorphic Ventricular Tachycardia” (MeSH), applying the same filters yielded 467 results. The abstracts of these articles were studied, and the articles were categorized and organized. Articles of relevance were read in full. As and where applicable, relevant references and citations from the primary articles where further explored and read in full.
Collapse
Affiliation(s)
- Shashank P Behere
- Department of Pediatrics, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Steven N Weindling
- Department of Pediatric Cardiology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire, USA
| |
Collapse
|
35
|
Abstract
A sudden unexplained death is felt to be due to a primary arrhythmic disorder when no structural heart disease is found on autopsy, and there is no preceding documentation of heart disease. In these cases, death is presumed to be secondary to a lethal and potentially heritable abnormality of cardiac ion channel function. These channelopathies include congenital long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome, and short QT syndrome. In certain cases, genetic testing may have an important role in supporting a diagnosis of a primary arrhythmia disorder, and can also provide prognostic information, but by far the greatest strength of genetic testing lies in the screening of family members, who may be at risk. The purpose of this review is to describe the basic genetic and molecular pathophysiology of the primary inherited arrhythmia disorders, and to outline a rational approach to genetic testing, management, and family screening.
Collapse
Affiliation(s)
- Danna A Spears
- Division of Cardiology - Electrophysiology, University Health Network, Toronto General Hospital, Toronto, ON, Canada
| | - Michael H Gollob
- Division of Cardiology - Electrophysiology, University Health Network, Toronto General Hospital, Toronto, ON, Canada
| |
Collapse
|
36
|
Affiliation(s)
- Manoj N Obeyesekere
- From the Department of Cardiology, Northern Healthcare Group, Epping, Victoria, Australia (M.N.O.); Masonic Medical Research Laboratory, Utica, NY (C.A.); and Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada (A.D.K.).
| | - Charles Antzelevitch
- From the Department of Cardiology, Northern Healthcare Group, Epping, Victoria, Australia (M.N.O.); Masonic Medical Research Laboratory, Utica, NY (C.A.); and Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada (A.D.K.)
| | - Andrew D Krahn
- From the Department of Cardiology, Northern Healthcare Group, Epping, Victoria, Australia (M.N.O.); Masonic Medical Research Laboratory, Utica, NY (C.A.); and Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada (A.D.K.)
| |
Collapse
|
37
|
|
38
|
Iribarren C, Round AD, Peng JA, Lu M, Klatsky AL, Zaroff JG, Holve TJ, Prasad A, Stang P. Short QT in a cohort of 1.7 million persons: prevalence, correlates, and prognosis. Ann Noninvasive Electrocardiol 2014; 19:490-500. [PMID: 24829126 DOI: 10.1111/anec.12157] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Short QT syndrome (QTc ≤ 300 ms) is a novel hereditary channelopathy linked to syncope, paroxysmal atrial fibrillation, and sudden cardiac death. However, its epidemiological features remain unsettled. OBJECTIVES (1) To assess the prevalence of short QT in a large population-based sample; (2) to evaluate its demographic and clinical correlates and; (3) to determine its prognosis. METHODS A database of 6.4 million electrocardiograms (ECGs) obtained between 1995 and 2008 among 1.7 million persons was used. An internal, population-based method for heart rate correction (QTcreg ) was used and all ECGs with QTcreg ≤300 ms were manually validated. Linked health plan databases were used for covariate and survival ascertainment. RESULTS Of 6,387,070 ECGs, 1086 had an ECG with machine-read QTcreg ≤300 ms. Only 4% (45/1086) were validated yielding a prevalence of 0.7 per 100,000 or 1 of 141,935 ECGs. At the person level, the overall prevalence of QTcreg ≤300 ms was 2.7 per 100,000 or 1 of 37,335. The factors independently and significantly associated with validated QTcreg ≤300 ms were age over 65 years, Black race, prior history of ventricular dysrhythmias, chronic obstructive pulmonary disease, ST-T abnormalities, ischemia, bigeminy pattern, and digitalis effect. After 8.3 years of median follow-up and relative to normal QTcreg , validated QTcreg ≤300 ms was associated after multivariate adjustment with a 2.6-fold (95% confidence interval [CI] = 1.9-3.7) increased risk of death. CONCLUSION QTcreg ≤300 ms was extraordinarily rare and was associated with significant ECG abnormalities and reduced survival.
Collapse
|
39
|
Mazzanti A, Kanthan A, Monteforte N, Memmi M, Bloise R, Novelli V, Miceli C, O'Rourke S, Borio G, Zienciuk-Krajka A, Curcio A, Surducan AE, Colombo M, Napolitano C, Priori SG. Novel insight into the natural history of short QT syndrome. J Am Coll Cardiol 2013; 63:1300-1308. [PMID: 24291113 PMCID: PMC3988978 DOI: 10.1016/j.jacc.2013.09.078] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/08/2013] [Accepted: 09/16/2013] [Indexed: 12/21/2022]
Abstract
Objectives This study intends to gain further insights into the natural history, the yield of familial and genetic screening, and the arrhythmogenic mechanisms in the largest cohort of short QT syndrome (SQTS) patients described so far. Background SQTS is a rare genetic disorder associated with life-threatening arrhythmias, and its natural history is incompletely ascertained. Methods Seventy-three SQTS patients (84% male; age, 26 ± 15 years; corrected QT interval, 329 ± 22 ms) were studied, and 62 were followed for 60 ± 41 months (median, 56 months). Results Cardiac arrest (CA) was the most frequent presenting symptom (40% of probands; range, <1 month to 41 years). The rate of CA was 4% in the first year of life and 1.3% per year between 20 and 40 years; the probability of a first occurrence of CA by 40 years of age was 41%. Despite the male predominance, female patients had a risk profile superimposable to that of men (p = 0.49). The yield of genetic screening was low (14%), despite familial disease being present in 44% of kindreds. A history of CA was the only predictor of recurrences at follow-up (p < 0.0000001). Two patterns of onset of ventricular fibrillation were observed and were reproducible in patients with multiple occurrences of CA. Arrhythmias occurred mainly at rest. Conclusions SQTS is highly lethal; CA is often the first manifestation of the disease with a peak incidence in the first year of life. Survivors of CA have a high CA recurrence rate; therefore, implantation of a defibrillator is strongly recommended in this group of patients.
Collapse
Affiliation(s)
- Andrea Mazzanti
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Ajita Kanthan
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Nicola Monteforte
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Mirella Memmi
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Raffaella Bloise
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Valeria Novelli
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Carlotta Miceli
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Sean O'Rourke
- Cardiovascular Genetics Program, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York
| | - Gianluca Borio
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | | | - Antonio Curcio
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | | | | | - Carlo Napolitano
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy; Cardiovascular Genetics Program, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York
| | - Silvia G Priori
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy; Cardiovascular Genetics Program, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York; Department of Molecular Medicine, University of Pavia, Pavia, Italy.
| |
Collapse
|
40
|
Adeniran I, Hancox JC, Zhang H. In silico investigation of the short QT syndrome, using human ventricle models incorporating electromechanical coupling. Front Physiol 2013; 4:166. [PMID: 23847545 PMCID: PMC3701879 DOI: 10.3389/fphys.2013.00166] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 06/14/2013] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Genetic forms of the Short QT Syndrome (SQTS) arise due to cardiac ion channel mutations leading to accelerated ventricular repolarization, arrhythmias and sudden cardiac death. Results from experimental and simulation studies suggest that changes to refractoriness and tissue vulnerability produce a substrate favorable to re-entry. Potential electromechanical consequences of the SQTS are less well-understood. The aim of this study was to utilize electromechanically coupled human ventricle models to explore electromechanical consequences of the SQTS. METHODS AND RESULTS The Rice et al. mechanical model was coupled to the ten Tusscher et al. ventricular cell model. Previously validated K(+) channel formulations for SQT variants 1 and 3 were incorporated. Functional effects of the SQTS mutations on [Ca(2+)] i transients, sarcomere length shortening and contractile force at the single cell level were evaluated with and without the consideration of stretch-activated channel current (I sac). Without I sac, at a stimulation frequency of 1Hz, the SQTS mutations produced dramatic reductions in the amplitude of [Ca(2+)] i transients, sarcomere length shortening and contractile force. When I sac was incorporated, there was a considerable attenuation of the effects of SQTS-associated action potential shortening on Ca(2+) transients, sarcomere shortening and contractile force. Single cell models were then incorporated into 3D human ventricular tissue models. The timing of maximum deformation was delayed in the SQTS setting compared to control. CONCLUSION The incorporation of I sac appears to be an important consideration in modeling functional effects of SQT 1 and 3 mutations on cardiac electro-mechanical coupling. Whilst there is little evidence of profoundly impaired cardiac contractile function in SQTS patients, our 3D simulations correlate qualitatively with reported evidence for dissociation between ventricular repolarization and the end of mechanical systole.
Collapse
Affiliation(s)
- Ismail Adeniran
- Computational Biology, Biological Physics Group, School of Physics and Astronomy, The University of Manchester Manchester, UK
| | | | | |
Collapse
|
41
|
Hsiao PY, Tien HC, Lo CP, Juang JMJ, Wang YH, Sung RJ. Gene mutations in cardiac arrhythmias: a review of recent evidence in ion channelopathies. Appl Clin Genet 2013; 6:1-13. [PMID: 23837003 PMCID: PMC3699290 DOI: 10.2147/tacg.s29676] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Over the past 15 years, molecular genetic studies have linked gene mutations to many inherited arrhythmogenic disorders, in particular, “ion channelopathies”, in which mutations in genes encode functional units of ion channels and/or their transporter-associated proteins in patients without primary cardiac structural abnormalities. These disorders are exemplified by congenital long QT syndrome (LQTS), short QT syndrome, Brugada syndrome (BrS) and catecholaminergic polymorphic ventricular tachycardia (CPVT). Functional and pathophysiological studies have led to better understanding of the clinical spectrum, ion channel structures and cellular electrophysiology involving dynamics of intracellular calcium cycling in many subtypes of these disorders and more importantly, development of potentially more effective pharmacological agents and even curative gene therapy. In this review, we have summarized (1) the significance of unveiling mutations in genes encoding transporter-associated proteins as the cause of congenital LQTS, (2) the technique of catheter ablation applied at the right ventricular outflow tract may be curative for severely symptomatic BrS, (3) mutations with channel function modulated by protein Kinase A-dependent phosphorylation can be the culprit of CPVT mimicry in Andersen-Tawil syndrome (LQT7), (4) ablation of the ion channel anchoring protein may prevent arrhythmogenesis in Timothy syndrome (LQT8), (5) altered intracellular Ca2+ cycling can be the basis of effective targeted pharmacotherapy in CPVT, and (6) the technology of induced pluripotent stem cells is a promising diagnostic and research tool as it has become a new paradigm for pathophysiological study of patient- and disease-specific cells aimed at screening new drugs and eventual clinical application of gene therapy. Lastly, we have discussed (7) genotype-phenotype correlation in relation to risk stratification of patients with congenital LQTS in clinical practice.
Collapse
Affiliation(s)
- Pi-Yin Hsiao
- Institute of Life Sciences, National Central University, Taoyuan, Taiwan
| | | | | | | | | | | |
Collapse
|
42
|
Thejus J, Francis J. Atrial fibrillation in cardiac channelopathies. Indian Pacing Electrophysiol J 2009; 9:342-50. [PMID: 19898657 PMCID: PMC2766582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|