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Liu W, Shao R, Zhang S, Jin L, Liu R, Chen P, Hu J, Ma H, Wu B, Liang W, Luo X, Li J, Chen W, Xiong N, He B. Characteristics, predictors and outcomes of new-onset QT prolongation in sepsis: a multicenter retrospective study. Crit Care 2024; 28:115. [PMID: 38594724 PMCID: PMC11003155 DOI: 10.1186/s13054-024-04879-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/17/2024] [Indexed: 04/11/2024] Open
Abstract
BACKGROUND Sepsis-induced myocardial injury is a serious complication of sepsis. QT prolongation is a proarrhythmic state which reflects myocardial injury in a group of heterogeneous disorders. However, the study on the clinical value of QT prolongation in sepsis is limited. METHODS We aimed to investigate the clinical characteristics and predictors of new-onset QT prolongation in sepsis and its impact on the outcome in a multicenter retrospective cohort study. Electrocardiographic and clinical data were collected from patients with sepsis from the wards and intensive care units of four centers after exclusion of QT-influencing medications and electrolyte abnormalities. Clinical outcomes were compared between patients with and without QT prolongation (QTc > 450 ms). Multivariate analysis was performed to ascertain whether QT prolongation was an independent predictor for 30-day mortality. The factors predicting QT prolongation in sepsis were also analyzed. RESULTS New-onset QT prolongation occurred in 235/1024 (22.9%) patients. The majority demonstrated similar pattern as type 1 long QT syndrome. Patients with QT prolongation had a higher 30-day in-hospital mortality (P < 0.001), which was also associated with increased tachyarrhythmias including paroxysmal atrial fibrillation or tachycardia (P < 0.001) and ventricular arrhythmia (P < 0.001) during hospitalization. QT prolongation independently predicted 30-day mortality (P = 0.044) after multivariate analysis. History of coronary artery disease (P = 0.001), septic shock (P = 0.008), acute respiratory (P < 0.001), heart (P = 0.021) and renal dysfunction (P = 0.013) were independent predictors of QT prolongation in sepsis. CONCLUSIONS New-onset QT prolongation in sepsis was associated with increased mortality as well as atrial and ventricular arrhythmias, which was predicted by disease severity and organ dysfunction.
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Affiliation(s)
- Weizhuo Liu
- Department of Critical Care Medicine, Shanghai Chest Hospital, Shanghai Jiaotong University School of Medicine, 241 Huaihaixi Road, Shanghai, 200030, China
- Centre for Cardiopulmonary Translational Medicine, Shanghai Chest Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Rongjiao Shao
- Department of Critical Care Medicine, Shanghai Chest Hospital, Shanghai Jiaotong University School of Medicine, 241 Huaihaixi Road, Shanghai, 200030, China
- Centre for Cardiopulmonary Translational Medicine, Shanghai Chest Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Shen Zhang
- Department of Critical Care Medicine, Shanghai Chest Hospital, Shanghai Jiaotong University School of Medicine, 241 Huaihaixi Road, Shanghai, 200030, China
| | - Lei Jin
- Department of Critical Care Medicine, Shanghai Chest Hospital, Shanghai Jiaotong University School of Medicine, 241 Huaihaixi Road, Shanghai, 200030, China
| | - Rongchen Liu
- Department of Cardiology, Huashan Hospital Fudan University, 12 Wulumuqizhong Road, Shanghai, 200030, China
| | - Peidong Chen
- Department of Infectious Diseases, Jing'an District Central Hospital of Shanghai, Fudan University, Shanghai, China
| | - Jintao Hu
- Department of Cardiology, People's Hospital of Qiubei, Putan Road in Jinping Town, Qiubei, 663200, Yunnan, China
| | - Haocheng Ma
- Department of Cardiology, People's Hospital of Qiubei, Putan Road in Jinping Town, Qiubei, 663200, Yunnan, China
- Department of Cardiology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Bangwei Wu
- Department of Cardiology, Huashan Hospital Fudan University, 12 Wulumuqizhong Road, Shanghai, 200030, China
| | - Weiguo Liang
- Department of Cardiology, Huashan Hospital Fudan University, 12 Wulumuqizhong Road, Shanghai, 200030, China
| | - Xinping Luo
- Department of Cardiology, Huashan Hospital Fudan University, 12 Wulumuqizhong Road, Shanghai, 200030, China
| | - Jian Li
- Department of Cardiology, Huashan Hospital Fudan University, 12 Wulumuqizhong Road, Shanghai, 200030, China
| | - Weiming Chen
- Department of Cardiology, People's Hospital of Qiubei, Putan Road in Jinping Town, Qiubei, 663200, Yunnan, China.
| | - Nanqing Xiong
- Department of Cardiology, Huashan Hospital Fudan University, 12 Wulumuqizhong Road, Shanghai, 200030, China.
| | - Bin He
- Department of Critical Care Medicine, Shanghai Chest Hospital, Shanghai Jiaotong University School of Medicine, 241 Huaihaixi Road, Shanghai, 200030, China.
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Yi J, Duan H, Chen K, Wen C, Cao Y, Gao H. Cardiac Electrophysiological Changes and Downregulated Connexin 43 Prompts Reperfusion Arrhythmias Induced by Hypothermic Ischemia-Reperfusion Injury in Isolated Rat Hearts. J Cardiovasc Transl Res 2022; 15:1464-1473. [PMID: 35689125 DOI: 10.1007/s12265-022-10256-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
The purpose of this study was to determine the utility of the monophasic action potential (MAP) changes as an arrhythmic biomarker in hypothermic ischemia-reperfusion. The hypothermic ischemia-reperfusion model was subjected to 60 min of cardioplegic arrest while the isolated rat hearts were preserved with a multidose cold K-H solution at 4 °C. During the reperfusion period, the heart's arrhythmia and monophasic action potential were also monitored. The myocardial damage was assessed using HE and TTC stains. Immunohistochemistry and Western blotting were used to assess the expression and distribution of Connexin 43 (Cx43) and Akt. Collectively, prolonged action potential durations, increased dispersion of repolarization, and downregulated and lateralized Cx43 all contribute to the derangement of electrical impulse propagation that may underlie arrhythmogenesis in the cold ischemic heart following cardioplegic arrest. MAP might be used as a biomarker for arrhythmias caused by hypothermic ischemia-reperfusion.
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Affiliation(s)
- Jing Yi
- Translational Medicine Research Center, Clinical Medical School, Guizhou Medical University, No. 9, Beijing Road, Guiyang, 550004, Guizhou, China
- Department of Anesthesiology, The Affiliated Hospital of Guizhou Medical University, No. 28, Guiyi Street, Guiyang, 550004, Guizhou, China
| | - Hongwei Duan
- Department of Anesthesiology, The Affiliated Pudong Hospital of Fudan University, No. 2800 Gongwei Road, Huinan Town, Pudong New Area 200120, Shanghai, China
| | - Kaiyuan Chen
- Translational Medicine Research Center, Clinical Medical School, Guizhou Medical University, No. 9, Beijing Road, Guiyang, 550004, Guizhou, China
| | - Chunlei Wen
- Translational Medicine Research Center, Clinical Medical School, Guizhou Medical University, No. 9, Beijing Road, Guiyang, 550004, Guizhou, China
| | - Ying Cao
- Translational Medicine Research Center, Clinical Medical School, Guizhou Medical University, No. 9, Beijing Road, Guiyang, 550004, Guizhou, China
| | - Hong Gao
- Translational Medicine Research Center, Clinical Medical School, Guizhou Medical University, No. 9, Beijing Road, Guiyang, 550004, Guizhou, China.
- Department of Equipment, The Affiliated Hospital of Guizhou Medical University, No. 28, Guiyi Street, Guiyang, 550004, Guizhou, China.
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3
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Occurrence of early afterdepolarization under healthy or hypertrophic cardiomyopathy conditions in the human ventricular endocardial myocyte: In silico study using 109 torsadogenic or non-torsadogenic compounds. Toxicol Appl Pharmacol 2022; 438:115914. [DOI: 10.1016/j.taap.2022.115914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/19/2022] [Accepted: 02/05/2022] [Indexed: 11/18/2022]
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4
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El-Sherif N, Turitto G, Boutjdir M. Acquired Long QT Syndrome and Electrophysiology of Torsade de Pointes. Arrhythm Electrophysiol Rev 2019; 8:122-130. [PMID: 31114687 PMCID: PMC6528034 DOI: 10.15420/aer.2019.8.3] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/04/2019] [Indexed: 12/16/2022] Open
Abstract
Congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. Although congenital LQTS remains the domain of cardiologists, cardiac electrophysiologists and specialised centres, the much more frequently acquired LQTS is the domain of physicians and other members of healthcare teams required to make therapeutic decisions. This paper reviews the electrophysiological mechanisms of acquired LQTS, its ECG characteristics, clinical presentation, and management. The paper concludes with a comprehensive review of the electrophysiological mechanisms of torsade de pointes.
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Affiliation(s)
- Nabil El-Sherif
- SUNY Downstate Medical CenterNY, US
- VA NY Harbor Healthcare SystemNY, US
| | - Gioia Turitto
- Weill Cornell Medical College, NewYork-Presbyterian Brooklyn Methodist HospitalNY, US
| | - Mohamed Boutjdir
- SUNY Downstate Medical CenterNY, US
- VA NY Harbor Healthcare SystemNY, US
- NYU School of MedicineNew York NY, US
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5
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El-Sherif N, Turitto G, Boutjdir M. Acquired long QT syndrome and torsade de pointes. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2018; 41:414-421. [PMID: 29405316 DOI: 10.1111/pace.13296] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 12/13/2017] [Accepted: 12/22/2017] [Indexed: 01/08/2023]
Abstract
Since its initial description by Jervell and Lange-Nielsen in 1957, the congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. Although congenital LQTS continues to remain the domain of cardiologists, cardiac electrophysiologists, and specialized centers, the by far more frequent acquired drug-induced LQTS is the domain of all physicians and other members of the health care team who are required to make therapeutic decisions. This report will review the electrophysiological mechanisms of LQTS and torsade de pointes, electrocardiographic characteristics of acquired LQTS, its clinical presentation, management, and future directions in the field.
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Affiliation(s)
- Nabil El-Sherif
- Downstate Medical Center, State University of New York, New York, NY, USA.,VA NY Harbor Healthcare System, New York, NY, USA
| | - Gioia Turitto
- New York-Presbyterian Brooklyn Methodist Hospital, New York, NY, USA
| | - Mohamed Boutjdir
- Downstate Medical Center, State University of New York, New York, NY, USA.,VA NY Harbor Healthcare System, New York, NY, USA.,NYU School of Medicine, New York, NY, USA
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6
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Marill KA, Dorsey P, Holmes A, Muthal K, Miller ES, Xue J. Is myocardial repolarization duration associated with repolarization heterogeneity? Ann Noninvasive Electrocardiol 2017; 23:e12519. [PMID: 29197146 DOI: 10.1111/anec.12519] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/18/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Dispersion of repolarization is theorized as one mechanism by which myocardial repolarization prolongation causes lethal torsades de pointes, (TdP). Our primary purpose was to determine whether prolongation of myocardial repolarization as measured by the heart rate-corrected J-to-T peak interval (JTpkc), is associated with repolarization heterogeneity as measured by transmural dispersion, defined as the median duration from the peak to the end of the T wave (TpTe). METHODS A retrospective cohort study was performed at a single urban tertiary ED from July 2011-September 2012. Inclusion criteria included all consecutive ED patients with ECG based on QTc and QRS intervals. Automated measurements of all intervals were performed. The association of JTpkc with the dependent variable TpTe was assessed after adjustment for QRS and RR interval durations with a multiple linear regression model. A secondary analysis included a similar adjusted assessment of the association of JTpkc with QT dispersion, QTd. Finally, we constructed two multiple regression models to assess the association of clinical causative factors of TdP with TpTe and JTpkc. RESULTS Eight hundred seventy-four cases were included: 186 with QTc <500 ms, 118 with QTc ≥500 and QRS ≥120 ms, and 570 with QTc ≥500 and QRS <120 ms. The coefficient for association of JTpkc with TpTe was -0.10 (95%CI -0.15 to -0.05), and for JTpkc with QTd was 0.03 (95% CI -0.01 to 0.06). Clinical causative TdP factors were associated more with JTpkc than TpTe. CONCLUSION Repolarization duration as measured by JTpkc is not positively associated with dispersion of repolarization as measured by TpTe or QTd. Dispersion of repolarization may not be a critical mechanistic link between QTc prolongation and TdP.
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Affiliation(s)
- Keith A Marill
- Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Pat Dorsey
- General Electric Healthcare, Milwaukee, WI, USA
| | | | - Ketaki Muthal
- Department of Biomedical Engineering, Massachusetts General Hospital, Boston, MA, USA
| | - Emily S Miller
- Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Joel Xue
- General Electric Healthcare, Milwaukee, WI, USA
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7
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Osadchii OE. Role of abnormal repolarization in the mechanism of cardiac arrhythmia. Acta Physiol (Oxf) 2017; 220 Suppl 712:1-71. [PMID: 28707396 DOI: 10.1111/apha.12902] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In cardiac patients, life-threatening tachyarrhythmia is often precipitated by abnormal changes in ventricular repolarization and refractoriness. Repolarization abnormalities typically evolve as a consequence of impaired function of outward K+ currents in cardiac myocytes, which may be caused by genetic defects or result from various acquired pathophysiological conditions, including electrical remodelling in cardiac disease, ion channel modulation by clinically used pharmacological agents, and systemic electrolyte disorders seen in heart failure, such as hypokalaemia. Cardiac electrical instability attributed to abnormal repolarization relies on the complex interplay between a provocative arrhythmic trigger and vulnerable arrhythmic substrate, with a central role played by the excessive prolongation of ventricular action potential duration, impaired intracellular Ca2+ handling, and slowed impulse conduction. This review outlines the electrical activity of ventricular myocytes in normal conditions and cardiac disease, describes classical electrophysiological mechanisms of cardiac arrhythmia, and provides an update on repolarization-related surrogates currently used to assess arrhythmic propensity, including spatial dispersion of repolarization, activation-repolarization coupling, electrical restitution, TRIaD (triangulation, reverse use dependence, instability, and dispersion), and the electromechanical window. This is followed by a discussion of the mechanisms that account for the dependence of arrhythmic vulnerability on the location of the ventricular pacing site. Finally, the review clarifies the electrophysiological basis for cardiac arrhythmia produced by hypokalaemia, and gives insight into the clinical importance and pathophysiology of drug-induced arrhythmia, with particular focus on class Ia (quinidine, procainamide) and Ic (flecainide) Na+ channel blockers, and class III antiarrhythmic agents that block the delayed rectifier K+ channel (dofetilide).
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Affiliation(s)
- O. E. Osadchii
- Department of Health Science and Technology; University of Aalborg; Aalborg Denmark
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8
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Marill KA, Miller ES. Hypokalemia in women and methadone therapy are the strongest non-cardiologic factors associated with QT prolongation in an emergency department setting. J Electrocardiol 2017; 50:416-423. [PMID: 28274542 DOI: 10.1016/j.jelectrocard.2017.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Indexed: 12/21/2022]
Abstract
BACKGROUND Our primary objective was to determine the adjusted quantitative associations of clinical predictors with QT prolongation, a defining cause of Torsades de Pointes (TdP). METHODS A retrospective cohort study was performed on consecutive emergency department patients identified by ECG acquisition date, and heart rate corrected QT (QTc) and QRS durations. QTc was modeled as a function of clinical predictors with multiple linear regression. RESULTS 1010 patients were included. The strongest predictors of QTc and their coefficients were: antidysrhythmic (26.1ms, 95% CI 15.6-36.6) and methadone (43.6ms, 95% CI 28.1-59.2) therapies, and genetic long QT syndrome diagnosis (32.6ms, 95% CI -4.7-70.0). The association of QTc with serum potassium was approximated by a two piecewise linear function that differed by sex. For potassium below 3.9mmol/L, QTc increased by 43.0ms (95% CI 26.2-59.7) and 29.5ms (95% CI 19.1-40.0) for every 1mmol/L decrease in potassium in women and men, respectively. TdP occurred in only 4/686 (0.6%) of patients with QTc≥500 and QRS<120, but mortality during the visit including hospitalization was 8.0%. CONCLUSIONS QTc duration is highly sensitive to hypokalemia, particularly in women. Methadone prolongs QTc remarkably compared to other non-cardiologic medicines. QTc>500 with normal QRS often signifies profound illness and substantial mortality risk, though not necessarily imminent TdP.
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Affiliation(s)
- Keith A Marill
- Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Emily S Miller
- Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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9
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Edwards AG, Louch WE. Species-Dependent Mechanisms of Cardiac Arrhythmia: A Cellular Focus. CLINICAL MEDICINE INSIGHTS-CARDIOLOGY 2017; 11:1179546816686061. [PMID: 28469490 PMCID: PMC5392019 DOI: 10.1177/1179546816686061] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/20/2016] [Indexed: 12/17/2022]
Abstract
Although ventricular arrhythmia remains a leading cause of morbidity and mortality, available antiarrhythmic drugs have limited efficacy. Disappointing progress in the development of novel, clinically relevant antiarrhythmic agents may partly be attributed to discrepancies between humans and animal models used in preclinical testing. However, such differences are at present difficult to predict, requiring improved understanding of arrhythmia mechanisms across species. To this end, we presently review interspecies similarities and differences in fundamental cardiomyocyte electrophysiology and current understanding of the mechanisms underlying the generation of afterdepolarizations and reentry. We specifically highlight patent shortcomings in small rodents to reproduce cellular and tissue-level arrhythmia substrate believed to be critical in human ventricle. Despite greater ease of translation from larger animal models, discrepancies remain and interpretation can be complicated by incomplete knowledge of human ventricular physiology due to low availability of explanted tissue. We therefore point to the benefits of mathematical modeling as a translational bridge to understanding and treating human arrhythmia.
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Affiliation(s)
- Andrew G Edwards
- Center for Biomedical Computing, Simula Research Laboratory, Lysaker, Norway.,Center for Cardiological Innovation, Simula Research Laboratory, Lysaker, Norway.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
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10
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Baker WL. Treating arrhythmias with adjunctive magnesium: identifying future research directions. EUROPEAN HEART JOURNAL - CARDIOVASCULAR PHARMACOTHERAPY 2016:pvw028. [DOI: 10.1093/ehjcvp/pvw028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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11
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Piccini JP, Pritchett EL, Davison BA, Cotter G, Wiener LE, Koch G, Feld G, Waldo A, van Gelder IC, Camm AJ, Kowey PR, Iwashita J, Dittrich HC. Randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of a single oral dose of vanoxerine for the conversion of subjects with recent onset atrial fibrillation or flutter to normal sinus rhythm: RESTORE SR. Heart Rhythm 2016; 13:1777-83. [DOI: 10.1016/j.hrthm.2016.04.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Indexed: 11/15/2022]
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12
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Effects of allocryptopine on outward potassium current and slow delayed rectifier potassium current in rabbit myocardium. JOURNAL OF GERIATRIC CARDIOLOGY : JGC 2016; 13:316-25. [PMID: 27403141 PMCID: PMC4921544 DOI: 10.11909/j.issn.1671-5411.2016.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Objective Allocryptopine (ALL) is an effective alkaloid of Corydalis decumbens (Thunb.) Pers. Papaveraceae and has proved to be anti-arrhythmic. The purpose of our study is to investigate the effects of ALL on transmural repolarizing ionic ingredients of outward potassium current (Ito) and slow delayed rectifier potassium current (IKs). Methods The monophasic action potential (MAP) technique was used to record the MAP duration of the epicardium (Epi), myocardium (M) and endocardium (Endo) of the rabbit heart and the whole cell patch clamp was used to record Ito and IKs in cardiomyocytes of Epi, M and Endo layers that were isolated from rabbit ventricles. Results The effects of ALL on MAP of Epi, M and Endo layers were disequilibrium. ALL could effectively reduce the transmural dispersion of repolarization (TDR) in rabbit transmural ventricular wall. ALL decreased the current densities of Ito and IKs in a voltage and concentration dependent way and narrowed the repolarizing differences among three layers. The analysis of gating kinetics showed ALL accelerated the channel activation of Ito in M layers and partly inhibit the channel openings of Ito in Epi, M and Endo cells. On the other hand, ALL mainly slowed channel deactivation of IKs channel in Epi and Endo layers without affecting its activation. Conclusions Our study gives partially explanation about the mechanisms of transmural inhibition of Ito and IKs channels by ALL in rabbit myocardium. These findings provide novel perspective regarding the anti-arrhythmogenesis application of ALL in clinical settings.
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13
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Arteyeva NV, Azarov JE. The Role of Transmural Repolarization Gradient in the Inversion of Cardiac Electric Field: Model Study of ECG in Hypothermia. Ann Noninvasive Electrocardiol 2016; 22. [PMID: 27018036 DOI: 10.1111/anec.12360] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 01/24/2016] [Accepted: 02/11/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The changes in ventricular repolarization gradients lead to significant alterations of the electrocardiographic body surface T waves up to the T wave inversion. However, the contribution of a specific gradient remains to be elucidated. The objective of the present investigation was to study the role of the transmural repolarization gradient in the inversion of the body surface T wave with a mathematical model of the hypothermia-induced changes of ventricular repolarization. METHODS By means of mathematical simulation, we set the hypothermic action potential duration (APD) distribution on the rabbit ventricular epicardium as it was previously experimentally documented. Then the parameters of the body surface potential distribution were tested with the introduction of different scenarios of the endocardial and epicardial APD behavior in hypothermia resulting in the unchanged, reversed or enlarged transmural repolarization gradient. RESULTS The reversal of epicardial repolarization gradients (apicobasal, anterior-posterior and interventricular) caused the inversion of the T waves regardless of the direction of the transmural repolarization gradient. However, the most realistic body surface potentials were obtained when the endocardial APDs were not changed under hypothermia while the epicardial APDs prolonged. This produced the reversed and increased transmural repolarization gradient in absolute magnitude. The body surface potentials simulated under the unchanged transmural gradient were reduced in comparison to those simulated under the reversed transmural gradient. CONCLUSIONS The simulations demonstrated that the transmural repolarization gradient did not play a crucial role in the cardiac electric field inversion under hypothermia, but its magnitude and direction contribute to the T wave amplitude.
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Affiliation(s)
- Natalia V Arteyeva
- Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia
| | - Jan E Azarov
- Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia.,Department of Physiology, Medical Institute of Syktyvkar State University, Syktyvkar, Russia.,Department of Cardiology, Lund University, Lund, Sweden
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14
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Frommeyer G, Eckardt L. Drug-induced proarrhythmia: risk factors and electrophysiological mechanisms. Nat Rev Cardiol 2015; 13:36-47. [PMID: 26194552 DOI: 10.1038/nrcardio.2015.110] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Drug-induced ventricular tachyarrhythmias can be caused by cardiovascular drugs, noncardiovascular drugs, and even nonprescription agents. They can result in arrhythmic emergencies and sudden cardiac death. If a new arrhythmia or aggravation of an existing arrhythmia develops during therapy with a drug at a concentration usually considered not to be toxic, the situation can be defined as proarrhythmia. Various cardiovascular and noncardiovascular drugs can increase the occurrence of polymorphic ventricular tachycardia of the 'torsade de pointes' type. Antiarrhythmic drugs, antimicrobial agents, and antipsychotic and antidepressant drugs are the most important groups. Age, female sex, and structural heart disease are important risk factors for the occurrence of torsade de pointes. Genetic predisposition and individual pharmacodynamic and pharmacokinetic sensitivity also have important roles in the generation of arrhythmias. An increase in spatial or temporal dispersion of repolarization and a triangular action-potential configuration have been identified as crucial predictors of proarrhythmia in experimental models. These studies emphasized that sole consideration of the QT interval is not sufficient to assess the proarrhythmic risk. In this Review, we focus on important triggers of proarrhythmia and the underlying electrophysiological mechanisms that can enhance or prevent the development of torsade de pointes.
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Affiliation(s)
- Gerrit Frommeyer
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Albert-Schweitzer Strasse 33, D-48149 Münster, Germany
| | - Lars Eckardt
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Albert-Schweitzer Strasse 33, D-48149 Münster, Germany
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15
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Ware WA, Reina-Doreste Y, Stern JA, Meurs KM. Sudden death associated with QT interval prolongation and KCNQ1 gene mutation in a family of English Springer Spaniels. J Vet Intern Med 2015; 29:561-8. [PMID: 25779927 PMCID: PMC4895492 DOI: 10.1111/jvim.12550] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 12/22/2014] [Accepted: 01/06/2015] [Indexed: 01/04/2023] Open
Abstract
Background A 5‐year‐old, healthy English Springer Spaniel died suddenly 4 months after delivering a litter of 7 puppies. Within 4 months of the dam's death, 3 offspring also died suddenly. Hypothesis Abnormal cardiac repolarization, caused by an inherited long QT syndrome, is thought to be responsible for arrhythmias leading to sudden death in this family. Animals Four remaining dogs from the affected litter and 11 related dogs. Methods Physical examination and resting ECG were done on the littermates and 9 related dogs. Additional tests on some or all littermates included echocardiogram with Doppler, Holter monitoring, and routine serum biochemistry. Blood for DNA sequencing was obtained from all 15 dogs. Results Three of 4 littermates examined, but no other dogs, had prolonged QT intervals with unique T‐wave morphology. DNA sequencing of the KCNQ1 gene identified a heterozygous single base pair mutation, unique to these 3 dogs, which changes a conserved amino acid from threonine to lysine and is predicted to change protein structure. Conclusions and Clinical Importance This family represents the first documentation in dogs of spontaneous familial QT prolongation, which was associated with a KCNQ1 gene mutation and sudden death. Although the final rhythm could not be documented in these dogs, their phenotypic manifestations of QT interval prolongation and abnormal ECG restitution suggested increased risk for sudden arrhythmic death. The KCNQ1 gene mutation identified is speculated to impair the cardiac repolarizing current IKs, similar to KCNQ1 mutations causing long QT syndrome 1 in humans.
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Affiliation(s)
- W A Ware
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA
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Kleiman RB, Shah RR, Morganroth J. Replacing the thorough QT study: reflections of a baby in the bath water. Br J Clin Pharmacol 2014; 78:195-201. [PMID: 24286381 PMCID: PMC4137815 DOI: 10.1111/bcp.12296] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 11/21/2013] [Indexed: 01/03/2023] Open
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Heijman J, Voigt N, Carlsson LG, Dobrev D. Cardiac safety assays. Curr Opin Pharmacol 2014; 15:16-21. [DOI: 10.1016/j.coph.2013.11.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 11/04/2013] [Accepted: 11/07/2013] [Indexed: 12/22/2022]
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The role of acute hyperinsulinemia in the development of cardiac arrhythmias. Naunyn Schmiedebergs Arch Pharmacol 2013; 386:435-44. [PMID: 23474828 DOI: 10.1007/s00210-013-0845-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 02/20/2013] [Indexed: 10/27/2022]
Abstract
Patients with perturbed metabolic control are more prone to develop cardiac rhythm disturbances. The main purpose of the present preclinical study was to investigate the possible role of euglycemic hyperinsulinemia in development of cardiac arrhythmias. Euglycemic hyperinsulinemia was induced in conscious rabbits equipped with a right ventricular pacemaker electrode catheter by hyperinsulinemic euglycemic glucose clamp (HEGC) applying two different rates of insulin infusion (5 and 10 mIU/kg/min) and variable rate of glucose infusion to maintain euglycemia (5.5 ± 0.5 mmol/l). The effect of hyperinsulinemia on cardiac electrophysiological parameters was continuously monitored by means of 12-lead surface ECG recording. Arrhythmia incidence was determined by means of programmed electrical stimulation (PES). The possible role of adrenergic activation was investigated by determination of plasma catecholamine levels and intravenous administration of a beta adrenergic blocking agent, metoprolol. All of the measurements were performed during the steady-state period of HEGC and subsequent to metoprolol administration. Both 5 and 10 mIU/kg/min insulin infusion prolonged significantly QTend, QTc, and Tpeak-Tend intervals. The incidence of ventricular arrhythmias generated by PES was increased significantly by euglycemic hyperinsulinemia and exhibited linear relationship to plasma levels of insulin. No alteration on plasma catecholamine levels could be observed; however, metoprolol treatment restored the prolonged QTend, QTc, and Tpeak-Tend intervals and significantly reduced the hyperinsulinemia-induced increase of arrhythmia incidence. Euglycemic hyperinsulinemia can exert proarrhythmic effect presumably due to the enhancement of transmural dispersion of repolarization. Metoprolol treatment may be of benefit in hyperinsulinemia associated with increased incidence of cardiac arrhythmias.
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Soltysinska E, Thomsen MB. Torsades de Pointes in the Guinea-pig heart : editorial to: "dofetilide promotes repolarization abnormalities in perfused Guinea-pig heart" by O.E. Osadchii. Cardiovasc Drugs Ther 2012; 26:437-9. [PMID: 23011586 DOI: 10.1007/s10557-012-6417-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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