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Orlov O, Asfour A, Shchekochikhin D, Magomedova Z, Bogdanova A, Komarova A, Podianov M, Gromyko G, Pershina E, Nesterov A, Shilova A, Ionina N, Andreev D. Cardiac Magnetic Resonance in Patients with Suspected Tachycardia-Induced Cardiomyopathy: The Impact of Late Gadolinium Enhancement and Epicardial Fat Tissue. J Pers Med 2023; 13:1440. [PMID: 37888051 PMCID: PMC10607955 DOI: 10.3390/jpm13101440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/28/2023] Open
Abstract
Tachycardia-induced cardiomyopathy (TIC) is a reversible subtype of dilated cardiomyopathy (DCM) resulting from sustained supraventricular or ventricular tachycardia and diagnosed by the normalization of left ventricular ejection fraction (LVEF) after stable sinus rhythm restoration. The aim of this study was to determine the contribution of cardiac magnetic resonance (CMR) to the differential diagnosis of TIC and DCM with persistent atrial arrythmias in patients hospitalized for the first time with heart failure (HF) with reduced LVEF of nonischemic origin. A total of 29 patients (age: 58.2 ± 16.9 years; males: 65.5%; average EF: 37.0 ± 9.5%) with persistent atrial tachyarrhythmia and first decompensation of HF without known coronary artery diseases were included in this study. The patients successfully underwent cardioversion and were observed for 30 days. The study population was divided into groups of responders (TIC patients; N = 16), which implies achieving FF > 50% or its increase > 10% in 30 days of TIC, and non-responders (N = 13). The increase in left ventricle (LV) volumes measured using CMR was significantly higher in the non-responder group when compared with the responders (114.8 mL ± 25.1 vs. 68.1 mL ± 10.5, respectively, p < 0.05). Non-responders also demonstrated decreased interventricular septum thickness (9.1 ± 0.8 vs.11.5 ± 1.3, respectively, p < 0.05). Late gadolinium enhancement (LGE) was observed in 12 patients (41.4%). The prevalence of LGE was increased in the non-responder group (25.0% vs. 65.1%, respectively, p = 0.046). Notably, a septal mid-wall LGE pattern was found exclusively in the non-responders. Epicardial adipose tissue thickness was decreased in the non-responder group versus the TIC patients. Conclusion: Patients with TIC were found to have smaller atrial and ventricular dimensions in comparison to patients with DCM. In addition, LGE was more common in DCM patients.
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Affiliation(s)
- Oleg Orlov
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
| | - Aref Asfour
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
| | - Dmitry Shchekochikhin
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
- Moscow State Healthcare Institution, City Clinical Hospital №1, 8 Leninsky Ave., 119049 Moscow, Russia; (A.N.); (A.S.)
- Department Intervention Cardiology and Cardiac Rehabilitation, Pirogov Russian National Research Medical University, 1 Ostrovitianinova Str., 117997 Moscow, Russia
| | - Zainab Magomedova
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
| | - Alexandra Bogdanova
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
- Moscow State Healthcare Institution, City Clinical Hospital №1, 8 Leninsky Ave., 119049 Moscow, Russia; (A.N.); (A.S.)
- Department Intervention Cardiology and Cardiac Rehabilitation, Pirogov Russian National Research Medical University, 1 Ostrovitianinova Str., 117997 Moscow, Russia
| | - Anna Komarova
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
| | - Maxim Podianov
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
| | - Grigory Gromyko
- Department of Endovascular Diagnostics and Treatment, Russian Biotechnological University (ROSBIOTECH), 33 Talalikhina Str., 109029 Moscow, Russia
| | - Ekaterina Pershina
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
- Moscow State Healthcare Institution, City Clinical Hospital №1, 8 Leninsky Ave., 119049 Moscow, Russia; (A.N.); (A.S.)
- World-Class Research Center, “Digital Biodesign and Personalized Healthcare”, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia
| | - Alexey Nesterov
- Moscow State Healthcare Institution, City Clinical Hospital №1, 8 Leninsky Ave., 119049 Moscow, Russia; (A.N.); (A.S.)
- Department Intervention Cardiology and Cardiac Rehabilitation, Pirogov Russian National Research Medical University, 1 Ostrovitianinova Str., 117997 Moscow, Russia
| | - Alexandra Shilova
- Moscow State Healthcare Institution, City Clinical Hospital №1, 8 Leninsky Ave., 119049 Moscow, Russia; (A.N.); (A.S.)
- Department Intervention Cardiology and Cardiac Rehabilitation, Pirogov Russian National Research Medical University, 1 Ostrovitianinova Str., 117997 Moscow, Russia
| | - Natalya Ionina
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
| | - Dennis Andreev
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 8 Trubetskaya Str., 119991 Moscow, Russia; (O.O.); (Z.M.); (E.P.)
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Shi HY, Xie MS, Guo YH, Yang CX, Gu JN, Qiao Q, Di RM, Qiu XB, Xu YJ, Yang YQ. VEZF1 loss-of-function mutation underlying familial dilated cardiomyopathy. Eur J Med Genet 2023; 66:104705. [PMID: 36657711 DOI: 10.1016/j.ejmg.2023.104705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/17/2022] [Accepted: 01/15/2023] [Indexed: 01/18/2023]
Abstract
Dilated cardiomyopathy (DCM), characteristic of left ventricular or biventricular dilation with systolic dysfunction, is the most common form of cardiomyopathy, and a leading cause of heart failure and sudden cardiac death. Aggregating evidence highlights the underlying genetic basis of DCM, and mutations in over 100 genes have been causally linked to DCM. Nevertheless, due to pronounced genetic heterogeneity, the genetic defects underpinning DCM in most cases remain obscure. Hence, this study was sought to identify novel genetic determinants of DCM. In this investigation, whole-exome sequencing and bioinformatics analyses were conducted in a family suffering from DCM, and a novel heterozygous mutation in the VEZF1 gene (coding for a zinc finger-containing transcription factor critical for cardiovascular development and structural remodeling), NM_007146.3: c.490A > T; p.(Lys164*), was identified. The nonsense mutation was validated by Sanger sequencing and segregated with autosome-dominant DCM in the family with complete penetrance. The mutation was neither detected in another cohort of 200 unrelated DCM patients nor observed in 400 unrelated healthy individuals nor retrieved in the Single Nucleotide Polymorphism database, the Human Gene Mutation Database and the Genome Aggregation Database. Biological analyses by utilizing a dual-luciferase reporter assay system revealed that the mutant VEZF1 protein failed to transactivate the promoters of MYH7 and ET1, two genes that have been associated with DCM. The findings indicate VEZF1 as a new gene responsible for DCM, which provides novel insight into the molecular pathogenesis of DCM, implying potential implications for personalized precisive medical management of the patients affected with DCM.
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Affiliation(s)
- Hong-Yu Shi
- Department of Cardiology, Zhongshan Hospital Wusong Branch, Fudan University, Shanghai, China
| | - Meng-Shi Xie
- Department of Cardiology, Zhongshan Hospital Wusong Branch, Fudan University, Shanghai, China
| | - Yu-Han Guo
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Chen-Xi Yang
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Jia-Ning Gu
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Qi Qiao
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Ruo-Min Di
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Xing-Biao Qiu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Ying-Jia Xu
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China.
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China; Department of Cardiovascular Research Laboratory, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China; Department of Central Laboratory, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China.
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Compagnucci P, Casella M, Bagliani G, Capestro A, Volpato G, Valeri Y, Cipolletta L, Parisi Q, Molini S, Misiani A, Russo AD. Atrial Flutter in Particular Patient Populations. Card Electrophysiol Clin 2022; 14:517-532. [PMID: 36153131 DOI: 10.1016/j.ccep.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
"Despite being one of the best understood cardiac arrhythmias, the clinical meaning of atrial flutter varies according to the specific context, and its optimal treatment may be limited by both the suboptimal response to rate/rhythm control drugs and by the complexity of the underlying substrate. In this article, we present a state-of-the-art overview of mechanisms, prognostic impact, and medical/interventional management options for atrial flutter in several specific patient populations, including heart failure, cardiomyopathies, muscular dystrophies, posttransplant patients, patients with respiratory disorders, athletes, and subjects with preexcitation, aiming to stimulate further research in this challenging field and facilitate appropriate patient care."
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Affiliation(s)
- Paolo Compagnucci
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy; Department of Biomedical Sciences and Public Health, Marche Polytechnic University, Ancona, Italy.
| | - Michela Casella
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy; Department of Clinical, Special and Dental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Giuseppe Bagliani
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy; Department of Biomedical Sciences and Public Health, Marche Polytechnic University, Ancona, Italy
| | - Alessandro Capestro
- Department of Pediatric and Congenital Cardiology and Cardiac Surgery, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy
| | - Giovanni Volpato
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy; Department of Biomedical Sciences and Public Health, Marche Polytechnic University, Ancona, Italy
| | - Yari Valeri
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy; Department of Biomedical Sciences and Public Health, Marche Polytechnic University, Ancona, Italy
| | - Laura Cipolletta
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy
| | - Quintino Parisi
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy
| | - Silvano Molini
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy
| | - Agostino Misiani
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy
| | - Antonio Dello Russo
- Cardiology and Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, Ancona 60126, Italy; Department of Clinical, Special and Dental Sciences, Marche Polytechnic University, Ancona, Italy
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Coscarella IL, Landim-Vieira M, Pinto JR, Chelko SP. Arrhythmogenic Cardiomyopathy: Exercise Pitfalls, Role of Connexin-43, and Moving beyond Antiarrhythmics. Int J Mol Sci 2022; 23:ijms23158753. [PMID: 35955883 PMCID: PMC9369094 DOI: 10.3390/ijms23158753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/28/2022] [Accepted: 08/03/2022] [Indexed: 12/11/2022] Open
Abstract
Arrhythmogenic Cardiomyopathy (ACM), a Mendelian disorder that can affect both left and right ventricles, is most often associated with pathogenic desmosomal variants that can lead to fibrofatty replacement of the myocardium, a pathological hallmark of this disease. Current therapies are aimed to prevent the worsening of disease phenotypes and sudden cardiac death (SCD). Despite the use of implantable cardioverter defibrillators (ICDs) there is no present therapy that would mitigate the loss in electrical signal and propagation by these fibrofatty barriers. Recent studies have shown the influence of forced vs. voluntary exercise in a variety of healthy and diseased mice; more specifically, that exercised mice show increased Connexin-43 (Cx43) expression levels. Fascinatingly, increased Cx43 expression ameliorated the abnormal electrical signal conduction in the myocardium of diseased mice. These findings point to a major translational pitfall in current therapeutics for ACM patients, who are advised to completely cease exercising and already demonstrate reduced Cx43 levels at the myocyte intercalated disc. Considering cardiac dysfunction in ACM arises from the loss of cardiomyocytes and electrical signal conduction abnormalities, an increase in Cx43 expression-promoted by low to moderate intensity exercise and/or gene therapy-could very well improve cardiac function in ACM patients.
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Affiliation(s)
- Isabella Leite Coscarella
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32303, USA
| | - Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32303, USA
| | - José Renato Pinto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32303, USA
| | - Stephen P. Chelko
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32303, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21215, USA
- Correspondence: ; Tel.: +1-850-644-2215
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5
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Nam MCY, Sparks PB. Intra‐atrial dissociation during catheter ablation of right septal atrial flutter in lamin cardiomyopathy. Intern Med J 2022; 52:889-890. [DOI: 10.1111/imj.15782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/13/2022] [Accepted: 03/29/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Michael C. Y. Nam
- Department of Cardiology Royal Melbourne Hospital Melbourne Victoria Australia
| | - Paul B. Sparks
- Department of Cardiology Royal Melbourne Hospital Melbourne Victoria Australia
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Increased cytosolic calcium buffering contributes to a cellular arrhythmogenic substrate in iPSC-cardiomyocytes from patients with dilated cardiomyopathy. Basic Res Cardiol 2022; 117:5. [PMID: 35499658 PMCID: PMC9061684 DOI: 10.1007/s00395-022-00912-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 01/31/2023]
Abstract
Dilated cardiomyopathy (DCM) is a major risk factor for heart failure and is associated with the development of life-threatening cardiac arrhythmias. Using a patient-specific induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) model harbouring a mutation in cardiac troponin T (R173W), we aim to examine the cellular basis of arrhythmogenesis in DCM patients with this mutation. iPSC from control (Ctrl) and DCM-TnT-R173W donors from the same family were differentiated into iPSC-CM and analysed through optical action potential (AP) recordings, simultaneous measurement of cytosolic calcium concentration ([Ca2+]i) and membrane currents and separately assayed using field stimulation to detect the threshold for AP- and [Ca2+]i-alternans development. AP duration was unaltered in TnT-R173W iPSC-CM. Nevertheless, TnT-R173W iPSC-CM showed a strikingly low stimulation threshold for AP- and [Ca2+]i-alternans. Myofilaments are known to play a role as intracellular Ca2+ buffers and here we show increased Ca2+ affinity of intracellular buffers in TnT-R173W cells, indicating increased myofilament sensitivity to Ca2+. Similarly, EMD57033, a myofilament Ca2+ sensitiser, replicated the abnormal [Ca2+]i dynamics observed in TnT-R173W samples and lowered the threshold for alternans development. In contrast, application of a Ca2+ desensitiser (blebbistatin) to TnT-R173W iPSC-CM was able to phenotypically rescue Ca2+ dynamics, normalising Ca2+ transient profile and minimising the occurrence of Ca2+ alternans at physiological frequencies. This finding suggests that increased Ca2+ buffering likely plays a major arrhythmogenic role in patients with DCM, specifically in those with mutations in cardiac troponin T. In addition, we propose that modulation of myofilament Ca2+ sensitivity could be an effective anti-arrhythmic target for pharmacological management of this disease.
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Mechanisms underlying pathological Ca 2+ handling in diseases of the heart. Pflugers Arch 2021; 473:331-347. [PMID: 33399957 PMCID: PMC10070045 DOI: 10.1007/s00424-020-02504-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/01/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Cardiomyocyte contraction relies on precisely regulated intracellular Ca2+ signaling through various Ca2+ channels and transporters. In this article, we will review the physiological regulation of Ca2+ handling and its role in maintaining normal cardiac rhythm and contractility. We discuss how inherited variants or acquired defects in Ca2+ channel subunits contribute to the development or progression of diseases of the heart. Moreover, we highlight recent insights into the role of protein phosphatase subunits and striated muscle preferentially expressed protein kinase (SPEG) in atrial fibrillation, heart failure, and cardiomyopathies. Finally, this review summarizes current drug therapies and new advances in genome editing as therapeutic strategies for the cardiac diseases caused by aberrant intracellular Ca2+ signaling.
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Li Y, Chen K, Dai Y, Li C, Sun Q, Chen R, Yan L, Lin J, Zhang S. Recovery of complete left bundle branch block following heart failure improvement by left bundle branch pacing in a patient. J Cardiovasc Electrophysiol 2019; 30:1714-1717. [PMID: 31206858 DOI: 10.1111/jce.14034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/05/2019] [Accepted: 06/12/2019] [Indexed: 11/27/2022]
Abstract
A 57-year-old male presented with symptomatic systolic heart failure and complete left bundle branch block (LBBB). Left bundle branch pacing corrected LBBB at a low capture threshold (0.5V @0.4ms) with right bundle branch conduction delay and paced QRS morphology changed to near-normal by adjusting AV delay with diminished RBBD. At 1-year follow-up, the patient had a significant improvement in heart failure and LBBB automatically resolved with a rate-dependent pattern. LBBP may be an alternative to conventional cardiac resynchronization therapy with the likelihood of recovery of LBBB. More research is needed to evaluate the potential use of this pacing strategy in patients with LBBB and heart failure.
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Affiliation(s)
- Yuqiu Li
- State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Keping Chen
- State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yan Dai
- State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chao Li
- State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qi Sun
- State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ruohan Chen
- State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lirong Yan
- State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jinxuan Lin
- State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shu Zhang
- State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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McElwee SK, Velasco A, Doppalapudi H. Mechanisms of sudden cardiac death. J Nucl Cardiol 2016; 23:1368-1379. [PMID: 27457531 DOI: 10.1007/s12350-016-0600-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 05/10/2016] [Indexed: 12/24/2022]
Abstract
Sudden cardiac death (SCD) continues to be a major public health problem and is thought to account for almost half of all cardiac deaths. Cardiac arrest and SCD are most commonly due to ventricular arrhythmias. Most patients who suffer cardiac arrest have underlying structural heart disease, with coronary artery disease (CAD) being the most common. In the setting of CAD, ventricular arrhythmias can result due to acute ischemia in the absence of preexisting myocardial scarring or in the presence of established scar from prior infarction without clinically significant ischemia. LV systolic dysfunction is an important predictor of risk for SCD in ischemic heart disease and in most nonischemic disorders, although other factors such as ventricular hypertrophy also play a role. Cardiac arrest and SCD can also occur due to primary electrical disorders in the absence of major structural abnormalities.
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Affiliation(s)
- Samuel K McElwee
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alejandro Velasco
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Harish Doppalapudi
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA.
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12
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Finsterer J, Zarrouk-Mahjoub S. Pathogenicity of the Homoplasmic m.8701A>G Variant Requires Confirmation. Chin Med J (Engl) 2016; 129:1889-90. [PMID: 27453249 PMCID: PMC4976588 DOI: 10.4103/0366-6999.186655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Markandeya YS, Tsubouchi T, Hacker TA, Wolff MR, Belardinelli L, Balijepalli RC. Inhibition of late sodium current attenuates ionic arrhythmia mechanism in ventricular myocytes expressing LaminA-N195K mutation. Heart Rhythm 2016; 13:2228-2236. [PMID: 27498076 DOI: 10.1016/j.hrthm.2016.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Lamin A and C are nuclear filament proteins encoded by the LMNA gene. Mutations in the LMNA gene cause many congenital diseases known as laminopathies, including Emery-Dreifuss muscular dystrophy, Hutchinson-Gilford progeria syndrome, and familial dilated cardiomyopathy (DCM) with conduction disease. A missense mutation (N195K) in the A-type lamins results in familial DCM and sudden arrhythmic death. OBJECTIVE The purpose of this study was to investigate the ion current mechanism of arrhythmia and DCM caused by the LaminA-N195K variant. METHODS A homozygous mouse line expressing the Lmna-N195K mutation (LmnaN195K/N195K) that exhibited arrhythmia, DCM, and sudden death was used. Using whole cell patch-clamp technique, we measured action potential duration (APD), Na+ currents (INa) in ventricular myocytes isolated from LmnaN195K/N195K, and wild-type mice. RESULTS Both peak and late INa were significantly (P <.05) increased in LmnaN195K/N195K ventricular myocytes. Similarly, LmnaN195K/N195K ventricular myocytes exhibited significant (P <.005) prolongation of APD (time to 50% [APD50] and 90% [APD90] repolarization) and triggered activity. Acute application of ranolazine inhibited late INa, shortened APD, and abolished triggered activity in LmnaN195K/N195K ventricular myocytes. CONCLUSION Inhibition of late INa may be an effective therapy in preventing arrhythmia in patients with LmnaN195K mutation-related DCM.
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Affiliation(s)
- Yogananda S Markandeya
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin, Madison, Wisconsin
| | - Tadashi Tsubouchi
- Preclinical Research Laboratories, Sumitomo Dainippon Pharma Co. Ltd., Osaka, Japan
| | - Timothy A Hacker
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin, Madison, Wisconsin
| | - Matthew R Wolff
- Meriter UnityPoint Heart and Vascular Institute, Madison, Wisconsin
| | | | - Ravi C Balijepalli
- Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin, Madison, Wisconsin.
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