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Parikh R, Bohora S, Rane S, Bansal R, Patel K. Analysis of ST segment depression in supraventricular tachycardia and its relationship with underlying mechanism. Indian Pacing Electrophysiol J 2024:S0972-6292(24)00076-7. [PMID: 38960131 DOI: 10.1016/j.ipej.2024.06.007] [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: 09/08/2023] [Revised: 06/07/2024] [Accepted: 06/14/2024] [Indexed: 07/05/2024] Open
Abstract
BACKGROUND Electrocardiographic diagnosis of causes of supraventricular tachycardia (SVT) is sometimes difficult and application of routine algorithms can lead to misdiagnosis in as many as 37 % of patients. ST segment depression may be useful in diagnosing the nature of SVT. METHODS We reviewed surface electrocardiogram (ECG) characteristics of 300 patients having SVT with 1:1 AV relationship and correlated findings with electrophysiology study (EPS) findings. Final diagnosis of AVNRT (Atrioventricular nodal reentrant tachycardia), Orthodromic AVRT (atrioventricular reentrant tachycardia) and atrial tachycardia (AT) was correlated with ECG parameters like heart rate, ST segment depressions and QRS morphology. RESULTS Out of 300 patients, majority patients included in study, were having AVNRT or AVRT. ST depression predicted AVRT if the ST depression was ≥ 2 mm (overall sensitivity of 38.3 % and specificity of 93.8 % to predict AVRT) and was downsloping in morphology (sensitivity of 36.9 % and specificity of 94.7 % to predict AVRT). At heart rates ≥214 beats per minute (bpm) as measured by 7 small squares of ECG at 25 mm/s, downsloping ST depression ≥2 mm had a sensitivity 37.9 % of and specificity of 89.2 % to predict AVRT. At heart rate <214 bpm, downsloping ST depression ≥2 mm had sensitivity of 37.2 % and specificity of 96.5 % to predict AVRT. Downsloping ST depression of ≥2 mm helps to differentiate AVNRT from AVRT. CONCLUSION A downsloping ST segment depression ≥2 mm predicted SVT being an AVRT and can be used as a useful criteria in diagnosing the tachycardia.
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Affiliation(s)
- Rujuta Parikh
- Department of cardiology U.N.Mehta Institute of Cardiology and Research Centre (UNMICRC), Civil Hospital Campus, Asarwa, Ahmedabad, 380016, Gujarat, India.
| | - Shomu Bohora
- Department of cardiology U.N.Mehta Institute of Cardiology and Research Centre (UNMICRC), Civil Hospital Campus, Asarwa, Ahmedabad, 380016, Gujarat, India.
| | - Sameer Rane
- Department of cardiology U.N.Mehta Institute of Cardiology and Research Centre (UNMICRC), Civil Hospital Campus, Asarwa, Ahmedabad, 380016, Gujarat, India.
| | - Raghav Bansal
- Department of cardiology U.N.Mehta Institute of Cardiology and Research Centre (UNMICRC), Civil Hospital Campus, Asarwa, Ahmedabad, 380016, Gujarat, India.
| | - Krutika Patel
- Department of Research, U. N. Mehta Institute of Cardiology and Research Centre (UNMICRC), Civil Hospital Campus, Asarwa, Ahmedabad, 380016, Gujarat, India.
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Habecker BA, Bers DM, Birren SJ, Chang R, Herring N, Kay MW, Li D, Mendelowitz D, Mongillo M, Montgomery JM, Ripplinger CM, Tampakakis E, Winbo A, Zaglia T, Zeltner N, Paterson DJ. Molecular and cellular neurocardiology in heart disease. J Physiol 2024. [PMID: 38778747 DOI: 10.1113/jp284739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 04/16/2024] [Indexed: 05/25/2024] Open
Abstract
This paper updates and builds on a previous White Paper in this journal that some of us contributed to concerning the molecular and cellular basis of cardiac neurobiology of heart disease. Here we focus on recent findings that underpin cardiac autonomic development, novel intracellular pathways and neuroplasticity. Throughout we highlight unanswered questions and areas of controversy. Whilst some neurochemical pathways are already demonstrating prognostic viability in patients with heart failure, we also discuss the opportunity to better understand sympathetic impairment by using patient specific stem cells that provides pathophysiological contextualization to study 'disease in a dish'. Novel imaging techniques and spatial transcriptomics are also facilitating a road map for target discovery of molecular pathways that may form a therapeutic opportunity to treat cardiac dysautonomia.
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Affiliation(s)
- Beth A Habecker
- Department of Chemical Physiology & Biochemistry, Department of Medicine Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis School of Medicine, Davis, CA, USA
| | - Susan J Birren
- Department of Biology, Volen Center for Complex Systems, Brandeis University, Waltham, MA, USA
| | - Rui Chang
- Department of Neuroscience, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Neil Herring
- Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Matthew W Kay
- Department of Biomedical Engineering, George Washington University, Washington, DC, USA
| | - Dan Li
- Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - David Mendelowitz
- Department of Pharmacology and Physiology, George Washington University, Washington, DC, USA
| | - Marco Mongillo
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Johanna M Montgomery
- Department of Physiology and Manaaki Manawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Crystal M Ripplinger
- Department of Pharmacology, University of California, Davis School of Medicine, Davis, CA, USA
| | | | - Annika Winbo
- Department of Physiology and Manaaki Manawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Tania Zaglia
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Nadja Zeltner
- Departments of Biochemistry and Molecular Biology, Cell Biology, and Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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3
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Horváth B, Kovács Z, Dienes C, Barta Z, Óvári J, Szentandrássy N, Magyar J, Bányász T, Nánási PP. Relationship between ion currents and membrane capacitance in canine ventricular myocytes. Sci Rep 2024; 14:11241. [PMID: 38755246 PMCID: PMC11099174 DOI: 10.1038/s41598-024-61736-6] [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: 02/21/2024] [Accepted: 05/09/2024] [Indexed: 05/18/2024] Open
Abstract
Current density, the membrane current value divided by membrane capacitance (Cm), is widely used in cellular electrophysiology. Comparing current densities obtained in different cell populations assume that Cm and ion current magnitudes are linearly related, however data is scarce about this in cardiomyocytes. Therefore, we statistically analyzed the distributions, and the relationship between parameters of canine cardiac ion currents and Cm, and tested if dividing original parameters with Cm had any effect. Under conventional voltage clamp conditions, correlations were high for IK1, moderate for IKr and ICa,L, while negligible for IKs. Correlation between Ito1 peak amplitude and Cm was negligible when analyzing all cells together, however, the analysis showed high correlations when cells of subepicardial, subendocardial or midmyocardial origin were analyzed separately. In action potential voltage clamp experiments IK1, IKr and ICa,L parameters showed high correlations with Cm. For INCX, INa,late and IKs there were low-to-moderate correlations between Cm and these current parameters. Dividing the original current parameters with Cm reduced both the coefficient of variation, and the deviation from normal distribution. The level of correlation between ion currents and Cm varies depending on the ion current studied. This must be considered when evaluating ion current densities in cardiac cells.
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Affiliation(s)
- Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
- Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary.
| | - Zsigmond Kovács
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Csaba Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zalán Barta
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - József Óvári
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Norbert Szentandrássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Division of Sport Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Department of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
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Kraft CJ, Namsrai BE, Tobolt D, Etheridge ML, Finger EB, Bischof JC. CPA toxicity screening of cryoprotective solutions in rat hearts. Cryobiology 2024; 114:104842. [PMID: 38158172 DOI: 10.1016/j.cryobiol.2023.104842] [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: 09/28/2023] [Revised: 11/21/2023] [Accepted: 12/20/2023] [Indexed: 01/03/2024]
Abstract
In clinical practice, donor hearts are transported on ice prior to transplant and discarded if cold ischemia time exceeds ∼5 h. Methods to extend these preservation times are critically needed, and ideally, this storage time would extend indefinitely, enabling improved donor-to-patient matching, organ utilization, and immune tolerance induction protocols. Previously, we demonstrated successful vitrification and rewarming of whole rat hearts without ice formation by perfusion-loading a cryoprotective agent (CPA) solution prior to vitrification. However, these hearts did not recover any beating even in controls with CPA loading/unloading alone, which points to the chemical toxicity of the cryoprotective solution (VS55 in Euro-Collins carrier solution) as the likely culprit. To address this, we compared the toxicity of another established CPA cocktail (VEG) to VS55 using ex situ rat heart perfusion. The CPA exposure time was 150 min, and the normothermic assessment time was 60 min. Using Celsior as the carrier, we observed partial recovery of function (atria-only beating) for both VS55 and VEG. Upon further analysis, we found that the VEG CPA cocktail resulted in 50 % lower LDH release than VS55 (N = 4, p = 0.017), suggesting VEG has lower toxicity than VS55. Celsior was a better carrier solution than alternatives such as UW, as CPA + Celsior-treated hearts spent less time in cardiac arrest (N = 4, p = 0.029). While we showed substantial improvement in cardiac function after exposure to vitrifiable concentrations of CPA by improving both the CPA and carrier solution formulation, further improvements will be required before we achieve healthy cryopreserved organs for transplant.
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Affiliation(s)
- Casey J Kraft
- Department of Biomedical Engineering, University of Minnesota, USA
| | | | - Diane Tobolt
- Department of Surgery, University of Minnesota, USA
| | | | - Erik B Finger
- Department of Surgery, University of Minnesota, USA.
| | - John C Bischof
- Department of Biomedical Engineering, University of Minnesota, USA; Department of Mechanical Engineering, University of Minnesota, USA; Institute for Engineering in Medicine, University of Minnesota, USA.
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Ponnusamy SS, Vijayaraman P. Pacing for atrioventricular block with preserved left ventricular function: On-treatment comparison between his bundle, left bundle branch, and right ventricular pacing. Indian Pacing Electrophysiol J 2023; 23:196-202. [PMID: 37776973 PMCID: PMC10685102 DOI: 10.1016/j.ipej.2023.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 09/03/2023] [Accepted: 09/21/2023] [Indexed: 10/02/2023] Open
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6
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Kihlgren M, Almqvist C, Amankhani F, Jonasson L, Norman C, Perez M, Ebrahimi A, Gottfridsson C. The U-wave: A remaining enigma of the electrocardiogram. J Electrocardiol 2023; 79:13-20. [PMID: 36907158 DOI: 10.1016/j.jelectrocard.2023.03.001] [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: 09/30/2022] [Revised: 02/24/2023] [Accepted: 03/01/2023] [Indexed: 03/07/2023]
Abstract
The U-wave's electrophysiological origin remains unknown and is subject to debate. It is rarely used for diagnosis in clinical practice. The aim of this study was to review new information regarding the U-wave. Further to present the proposed theories behind the U-wave's origin along with potential pathophysiologic and prognostic implications related to its presence, polarity and morphology. METHOD Literature searches were conducted to retrieve publications related to the electrocardiogram U-wave in the literature database Embase. RESULTS The review of the literature revealed the following major theories that will be discussed; late depolarisation, delayed or prolonged repolarisation, electro-mechanical stretch and IK1 dependent intrinsic potential differences in the terminal part of the action potential. Various pathologic conditions were found to correlate with the presence and properties of the U-wave, such as its amplitude and polarity. Abnormal U-waves can, for example, be observed in coronary artery disease with ongoing myocardial ischemia or infarction, ventricular hypertrophy, congenital heart disease, primary cardiomyopathy and valvular defects. Negative U-waves are highly specific for the presence of heart diseases. Concordantly negative T- and U-waves are especially associated with cardiac disease. Patients with negative U-waves tend to have higher blood pressure and history of hypertension, higher heart rate, cardiac disease and left ventricular hypertrophy compared to subjects with normal U-waves. Negative U-waves have been found to be associated with increased risk of all-cause mortality, cardiac death and cardiac hospitalisation in men. CONCLUSIONS The origin of the U-wave is still not established. U-wave diagnostics may reveal cardiac disorders and the cardiovascular prognosis. Including the U-wave characteristics in the clinical ECG assessment may be useful.
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Affiliation(s)
- Moa Kihlgren
- Cardiovascular Safety Center of Excellence and Safety Knowledge Groups, Global Patient Safety, Oncology R&D, AstraZeneca Gothenburg, Sweden.
| | - Christina Almqvist
- Cardiovascular Safety Center of Excellence and Safety Knowledge Groups, Global Patient Safety, Oncology R&D, AstraZeneca Gothenburg, Sweden.
| | - Fereydoun Amankhani
- Cardiovascular Safety Center of Excellence and Safety Knowledge Groups, Global Patient Safety, Oncology R&D, AstraZeneca Gothenburg, Sweden.
| | - Linda Jonasson
- Cardiovascular Safety Center of Excellence and Safety Knowledge Groups, Global Patient Safety, Oncology R&D, AstraZeneca Gothenburg, Sweden.
| | - Cecilia Norman
- Cardiovascular Safety Center of Excellence and Safety Knowledge Groups, Global Patient Safety, Oncology R&D, AstraZeneca Gothenburg, Sweden.
| | - Marcos Perez
- Cardiovascular Safety Center of Excellence and Safety Knowledge Groups, Global Patient Safety, Oncology R&D, AstraZeneca Gothenburg, Sweden.
| | - Ahmad Ebrahimi
- Cardiovascular Safety Center of Excellence and Safety Knowledge Groups, Global Patient Safety, Oncology R&D, AstraZeneca Gothenburg, Sweden.
| | - Christer Gottfridsson
- Cardiovascular Safety Center of Excellence and Safety Knowledge Groups, Global Patient Safety, Oncology R&D, AstraZeneca Gothenburg, Sweden.
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Fassina D, M Costa C, Bishop M, Plank G, Whitaker J, Harding SE, Niederer SA. Assessing the arrhythmogenic risk of engineered heart tissue patches through in silico application on infarcted ventricle models. Comput Biol Med 2023; 154:106550. [PMID: 36701966 DOI: 10.1016/j.compbiomed.2023.106550] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 01/02/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023]
Abstract
BACKGROUND Post myocardial infarction (MI) ventricles contain fibrotic tissue and may have disrupted electrical properties, both of which predispose to an increased risk of life-threatening arrhythmias. Application of epicardial patches obtained from human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a potential long-term therapy to treat heart failure resulting from post MI remodelling. However, whether the introduction of these patches is anti- or pro-arrhythmic has not been studied. METHODS We studied arrhythmic risk using in silico engineered heart tissue (EHT) patch engraftment on human post-MI ventricular models. Two patient models were studied, including one with a large dense scar and one with an apparent channel of preserved viability bordered on both sides by scar. In each heart model a virtual EHT patch was introduced as a layer of viable tissue overlying the scarred area, with hiPSC-CMs electrophysiological properties. The incidence of re-entrant and sustained activation in simulations with and without EHT patches was assessed and the arrhythmia inducibility compared in the context of different EHT patch properties (conduction velocity (CV) and action potential duration (APD)). The impact of the EHT patch on the likelihood of focal ectopic impulse propagation was estimated by assessing the minimum stimulus strength and duration required to generate a propagating impulse in the scar border zone (BZ) with and without patch. RESULTS We uncovered two main mechanisms by which ventricular tachycardia (VT) risk could be either augmented or attenuated by the interaction of the patch with the tissue. In the case of isthmus-related VT, our simulations predict that EHT patches can prevent the induction of VT when the, generally longer, hiPSC-CMs APD is reduced towards more physiological values. In the case of large dense scar, we found that, an EHT patch with CV similar to the host myocardium does not promote VT, while EHT patches with lower CV increase the risk of VT, by promoting both non-sustained and sustained re-entry. Finally, our simulations indicate that electrically coupled EHT patches reduce the likelihood of propagation of focal ectopic impulses. CONCLUSIONS The introduction of EHT patches as a treatment for heart failure has the potential to augment or attenuate the risk of ventricular arrhythmias, and variations in the anatomic configuration of the substrate, the functional properties of the BZ and the electrophysiologic properties of the patch itself will determine the overall impact. Planning for delivery of this therapy will need to consider the possible impact on arrhythmia.
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Affiliation(s)
- Damiano Fassina
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK; National Heart and Lung Institute, Imperial College London, London, UK.
| | - Caroline M Costa
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Martin Bishop
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | | | | | - Sian E Harding
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Steven A Niederer
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
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8
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Söylemez N, Yaman B. Association between ventricular premature contraction burden and ventricular repolarization duration. Rev Assoc Med Bras (1992) 2022; 68:1571-1575. [PMID: 36449776 PMCID: PMC9720762 DOI: 10.1590/1806-9282.20220676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 08/03/2022] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE Premature ventricular contraction is generally known as benign in the absence of structural heart disease; however, premature ventricular contraction-induced left ventricular systolic dysfunction or ventricular arrhythmias are defined in some cases. Ventricular repolarization duration differs between myocardial cells, which causes myocardial electrical heterogeneity and is thought to be responsible for ventricular arrhythmias. In our study, we aimed to evaluate the association of ventricular repolarization parameters including Tp-Te interval, Tp-Te/QT ratio, and QRS-T angle with premature ventricular contraction frequency in patients with premature ventricular contraction burden. METHODS A total of 80 subjects who were admitted to our cardiology department and underwent 24-h electrocardiography Holter monitoring were included. Patients were divided into two groups: group 1 is defined as premature ventricular contraction burden that had frequent premature ventricular contraction ≥1% in 24-h Holter monitoring, and group 2 is defined as rare premature ventricular contraction <1% in 24-h Holter monitoring. RESULTS Tp-Te interval and Tp-Te/QT ratio are statistically significantly prolonged in the premature ventricular contraction burden group than in the control group (85.3±13.9 vs. 65.7±11.9, p<0.001; 0.19±0.03 vs. 0.15±0.02, p<0.001, respectively). QRS-T angle was statistically significantly abnormal in the premature ventricular contraction burden group (p=0.024). CONCLUSION Increased Tp-Te interval and widened QRS-T angle are associated with ventricular arrhythmias and might be used for the prediction of premature ventricular contraction burden in patients with premature ventricular contraction in electrocardiography in the absence of 24-h Holter monitoring.
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Affiliation(s)
- Nihat Söylemez
- Mersin City Training and Research Hospital, Department of Cardiology – Mersin, Turkey
| | - Belma Yaman
- Yakın Doğu Üniversitesi, Faculty of Medicine, Department of Cardiology – Nicosia, Cyprus.,Corresponding author:
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Yakkali S, Teresa Selvin S, Thomas S, Bikeyeva V, Abdullah A, Radivojevic A, Abu Jad AA, Ravanavena A, Ravindra C, Igweonu-Nwakile EO, Ali S, Paul S, Hamid P. Why Is There an Increased Risk for Sudden Cardiac Death in Patients With Early Repolarization Syndrome? Cureus 2022; 14:e26820. [PMID: 35971350 PMCID: PMC9374281 DOI: 10.7759/cureus.26820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/13/2022] [Indexed: 11/29/2022] Open
Abstract
The last two decades have changed the viewpoint on early repolarization syndrome (ERS). The prevalence of the early repolarization pattern is variable and ranges between 3-24% depending upon age, gender, and criteria used for J-point upliftment from baseline (0.05mV vs. 1 mV). While this pattern was previously linked with a benign result, multiple recent investigations have found a link between early repolarization and Sudden Cardiac Death (SCD) by causing life-threatening arrhythmias like Ventricular tachycardia/Ventricular fibrillation, a condition known as early repolarization syndrome. The syndrome falls under a broader bracket of J wave syndromes, which can be caused by early repolarization or depolarization abnormalities. The characteristics of early repolarization that are considered high risk for Sudden Cardiac Death include the amplitude of J-point upliftment from baseline ( > 0.2 mV), Inferior-lateral location of Early Repolarization pattern, and horizontal and downsloping ST-segment. Patients with symptomatic early repolarisation patterns on ECG are more likely to have repeated cardiac episodes. Implantable Cardioverter-Defibrillator (ICD) implantation and isoproterenol are the recommended treatments in symptomatic patients. On the other hand, asymptomatic patients with early repolarization patterns are prevalent and have a better outcome. Risk categorization is still obscure in asymptomatic early repolarization patterns. This traditional review outlines the known knowledge of pathophysiology behind the increased risk of sudden cardiac death, risk stratification of patients with ERS, and the treatment guidelines for patients with ERS. Further prospective studies are recommended to elucidate the exact mechanism for ventricular arrhythmogenesis in ERS patients and to risk stratifying asymptomatic patients with ERS.
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Li D, Weng Y, Zhen G, Jiang L. Tp-Te Interval and Tp-Te/QT Ratio Are Valuable Tools in Predicting Poor Outcome in Sepsis Patients. Front Cardiovasc Med 2022; 9:879085. [PMID: 35677695 PMCID: PMC9167962 DOI: 10.3389/fcvm.2022.879085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Objective About 50% of patients with sepsis have different degrees of myocardial inhibition, known as sepsis-induced myocardial dysfunction (SMD), which increases the mortality rate of sepsis. Tp-Te interval and Tp-Te/QT ratio reflect ventricular transmural dispersion repolarization (TDR), and have good predictive value for death in patients with heart disease. This study aimed to investigate the prognostic value of Tp-Te and Tp-Te/QT in patients with sepsis. Methods The current study included a total of 625 participants: 201 patients with sepsis, 213 patients with heart failure, and 211 healthy participants. According to the severity and outcome, the patients with sepsis were divided into the sepsis group and the septic shock group, and the death group and the survival group to explore the differences of indicators among subgroups of sepsis. The ROC curve was used to analyze the predictive value of the indicators for deaths of patients with sepsis and calculate the cutoff point. Then, we investigated the incidence of arrhythmia in patients with sepsis with different TDR. The correlation between Tp-Te/QT and the commonly used predictive indicators in ICU was also discussed. Results (1) Tp-Te and Tp-Te/QT in patients with sepsis and heart failure (HF) were significantly higher than the control group (p < 0.01). (2) Compared with patients with sepsis, the increase of Tp-Te and Tp-Te/QT is more prominent in patients with HF. Especially, the increase of the Tp-Te/QT was statistically significant (p < 0.001). (3) compared with patients with sepsis (no shock), the Tp-Te, Tp-Te/QT, and SOFA were increased in patients with septic shock (p < 0.05). (4) In the death group, Tp-Te /QT, SOFA, and Apache-II were higher; LVEF was lower than the survival group (p < 0.05). (5) ROC curves showed that Tp-Te/QT, SOFA, and LVEF have predictive values for death (p < 0.05; AUC = 0.808, 0.716, 0.412). The cutoff point of Tp-Te/QT was 0.32. (6) The incidence of arrhythmia is different in patients with sepsis with different TDR. (7) There is a significant correlation between Tp-Te/QT and SOFA (p < 0.001, r = 0.79). Conclusion TDR in patients with sepsis is significantly increased, which was between healthy population and patients with HF. Tp-Te and Tp-Te/QT are effective indicators to reflect the severity and poor outcome of patients with sepsis.
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Affiliation(s)
- Duo Li
- Department of Critical Care Medicine, Fuxing Hospital, Capital Medical University, Beijing, China
- Department of Critical Care Medicine, Beijing Luhe Hospital, Capital Medical University, Beijing, China
| | - Yibing Weng
- Department of Critical Care Medicine, Beijing Luhe Hospital, Capital Medical University, Beijing, China
| | - Genshen Zhen
- Department of Critical Care Medicine, Beijing Luhe Hospital, Capital Medical University, Beijing, China
| | - Li Jiang
- Department of Critical Care Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
- *Correspondence: Li Jiang
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11
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Electro-anatomical computational cardiology in humans and experimental animal models. TRANSLATIONAL RESEARCH IN ANATOMY 2022. [DOI: 10.1016/j.tria.2022.100162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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12
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Vaykshnorayte MA, Vityazev VA, Azarov JE. Seasonal changes of electrophysiological heterogeneities in the rainbow trout ventricular myocardium. Curr Res Physiol 2022; 5:93-98. [PMID: 35198999 PMCID: PMC8844795 DOI: 10.1016/j.crphys.2022.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/09/2022] [Accepted: 02/04/2022] [Indexed: 11/28/2022] Open
Abstract
Introduction Thermal adaptation in fish is accompanied by morphological and electrophysiological changes in the myocardium. Little is known regarding seasonal changes of spatiotemporal organization of ventricular excitation and repolarization processes. We aimed to evaluate transmural and apicobasal heterogeneity of depolarization and repolarization characteristics in the rainbow trout in-situ ventricular myocardium in summer and winter conditions. Methods The experiments were done in summer-acclimatized (SA, 18°C, n = 8) and winter-acclimatized (WA, 3°C, n = 8) rainbow trout (Oncorhynchus mykiss). 24 unipolar electrograms were recorded with 3 plunge needle electrodes (eight lead terminals each) impaled into the ventricular wall. Activation time (AT), end of repolarization time (RT), and activation-repolarization interval (ARI, a surrogate for action potential duration) were determined as dV/dt min during QRS-complex, dV/dt max during T-wave, and RT-AT difference, respectively. Results The SA fish demonstrated relatively flat apicobasal and transmural AT and ARI profiles. In the WA animals, ATs and ARIs were longer as compared to SA animals (p≤0.001), ARIs were shorter in the compact layer than in the spongy layer (p≤0.050), and within the compact layer, the apical region had shorter ATs and longer ARIs as compared to the basal region (p≤0.050). In multiple linear regression analysis, ARI duration was associated with RR-interval and AT in SA and WA animals. The WA animals additionally demonstrated an independent association of ARIs with spatial localization across the ventricle. Conclusion Cold conditions led to the spatial redistribution of repolarization durations in the rainbow trout ventricle and the formation of repolarization gradients typically observed in mammalian myocardium. Spatiotemporal electrophysiological pattern is essential for cardiac function. A role of this pattern is unclear, specifically in seasonal changes in fish. Transmural repolarization gradients develop in cold conditions in rainbow trout.
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13
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Dokshokova L, Pianca N, Zaglia T, Mongillo M. Optogenetic Control of Heart Rhythm: Lightly Guiding the Cardiac Pace. Methods Mol Biol 2022; 2483:205-229. [PMID: 35286678 DOI: 10.1007/978-1-0716-2245-2_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
It is well appreciated that, differently from skeletal muscles, the heart contracts independently from neurogenic inputs. However, the speed and force of heartbeats are finely modulated during stresses, emotions, and daily activities, by the autonomic neurons (both parasympathetic and sympathetic) which highly innervate the myocardium. Despite this aspect of cardiac physiology has been known for long, research has only recently shed light on the biophysical mechanisms underlying the meticulous adaptation of heart activity to the needs of the organism. A conceptual advancement in this regard has come from the use of optogenetics, a revolutionary methodology which allows to control the activity of a given excitable cell type, with high specificity, temporal and spatial resolution, within intact tissues and organisms. The method, widely affirmed in the field of neuroscience, has more recently been exploited also in research on heart physiology and pathology, including the study of the mechanisms regulating heart rhythm. The last point is the object of this book chapter which, starting from the description of the physiology of heart rhythm automaticity and the neurogenic modulation of heart rate, makes an excursus on the theoretical basis of such biotechnology (with its advantages and limitations), and presents a series of examples in cardiac and neuro-cardiac optogenetics.
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Affiliation(s)
- Lolita Dokshokova
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | - Nicola Pianca
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | - Tania Zaglia
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
- Veneto Institute of Molecular Medicine, Padova, Italy.
| | - Marco Mongillo
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
- Veneto Institute of Molecular Medicine, Padova, Italy.
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14
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Canine Myocytes Represent a Good Model for Human Ventricular Cells Regarding Their Electrophysiological Properties. Pharmaceuticals (Basel) 2021; 14:ph14080748. [PMID: 34451845 PMCID: PMC8398821 DOI: 10.3390/ph14080748] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 12/19/2022] Open
Abstract
Due to the limited availability of healthy human ventricular tissues, the most suitable animal model has to be applied for electrophysiological and pharmacological studies. This can be best identified by studying the properties of ion currents shaping the action potential in the frequently used laboratory animals, such as dogs, rabbits, guinea pigs, or rats, and comparing them to those of human cardiomyocytes. The authors of this article with the experience of three decades of electrophysiological studies, performed in mammalian and human ventricular tissues and isolated cardiomyocytes, summarize their results obtained regarding the major canine and human cardiac ion currents. Accordingly, L-type Ca2+ current (ICa), late Na+ current (INa-late), rapid and slow components of the delayed rectifier K+ current (IKr and IKs, respectively), inward rectifier K+ current (IK1), transient outward K+ current (Ito1), and Na+/Ca2+ exchange current (INCX) were characterized and compared. Importantly, many of these measurements were performed using the action potential voltage clamp technique allowing for visualization of the actual current profiles flowing during the ventricular action potential. Densities and shapes of these ion currents, as well as the action potential configuration, were similar in human and canine ventricular cells, except for the density of IK1 and the recovery kinetics of Ito. IK1 displayed a largely four-fold larger density in canine than human myocytes, and Ito recovery from inactivation displayed a somewhat different time course in the two species. On the basis of these results, it is concluded that canine ventricular cells represent a reasonably good model for human myocytes for electrophysiological studies, however, it must be borne in mind that due to their stronger IK1, the repolarization reserve is more pronounced in canine cells, and moderate differences in the frequency-dependent repolarization patterns can also be anticipated.
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15
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Chaumont C, Suffee N, Gandjbakhch E, Balse E, Anselme F, Hatem SN. Epicardial origin of cardiac arrhythmias: clinical evidences and pathophysiology. Cardiovasc Res 2021; 118:1693-1702. [PMID: 34152392 PMCID: PMC9215195 DOI: 10.1093/cvr/cvab213] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/18/2021] [Indexed: 11/16/2022] Open
Abstract
Recent developments in imaging, mapping, and ablation techniques have shown that the epicardial region of the heart is a key player in the occurrence of ventricular arrhythmic events in several cardiac diseases, such as Brugada syndrome, arrhythmogenic cardiomyopathy, or dilated cardiomyopathy. At the atrial level as well, the epicardial region has emerged as an important determinant of the substrate of atrial fibrillation, pointing to common underlying pathophysiological mechanisms. Alteration in the gradient of repolarization between myocardial layers favouring the occurrence of re-entry circuits has largely been described. The fibro-fatty infiltration of the subepicardium is another shared substrate between ventricular and atrial arrhythmias. Recent data have emphasized the role of the epicardial reactivation in the formation of this arrhythmogenic substrate. There are new evidences supporting this structural remodelling process to be regulated by the recruitment of epicardial progenitor cells that can differentiate into adipocytes or fibroblasts under various stimuli. In addition, immune-inflammatory processes can also contribute to fibrosis of the subepicardial layer. A better understanding of such ‘electrical fragility’ of the epicardial area will open perspectives for novel biomarkers and therapeutic strategies. In this review article, a pathophysiological scheme of epicardial-driven arrhythmias will be proposed.
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Affiliation(s)
- Corentin Chaumont
- Cardiology Department, Rouen University Hospital, Rouen, France.,FHU REMOD-VHF, UNIROUEN, INSERM U1096, F76000, France
| | - Nadine Suffee
- INSERM UMRS1166, ICAN-Institute of CardioMetabolism and Nutrition, Sorbonne University, Institute of Cardiology, Pitié-Salpêtrière Hospital, Paris, France
| | - Estelle Gandjbakhch
- INSERM UMRS1166, ICAN-Institute of CardioMetabolism and Nutrition, Sorbonne University, Institute of Cardiology, Pitié-Salpêtrière Hospital, Paris, France
| | - Elise Balse
- INSERM UMRS1166, ICAN-Institute of CardioMetabolism and Nutrition, Sorbonne University, Institute of Cardiology, Pitié-Salpêtrière Hospital, Paris, France
| | - Frédéric Anselme
- Cardiology Department, Rouen University Hospital, Rouen, France.,FHU REMOD-VHF, UNIROUEN, INSERM U1096, F76000, France
| | - Stéphane N Hatem
- INSERM UMRS1166, ICAN-Institute of CardioMetabolism and Nutrition, Sorbonne University, Institute of Cardiology, Pitié-Salpêtrière Hospital, Paris, France
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16
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Dries E, Bardi I, Nunez-Toldra R, Meijlink B, Terracciano CM. CaMKII inhibition reduces arrhythmogenic Ca2+ events in subendocardial cryoinjured rat living myocardial slices. J Gen Physiol 2021; 153:212078. [PMID: 33956073 PMCID: PMC8105719 DOI: 10.1085/jgp.202012737] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 04/13/2021] [Indexed: 01/08/2023] Open
Abstract
Spontaneous Ca2+ release (SCR) can cause triggered activity and initiate arrhythmias. Intrinsic transmural heterogeneities in Ca2+ handling and their propensity to disease remodeling may differentially modulate SCR throughout the left ventricular (LV) wall and cause transmural differences in arrhythmia susceptibility. Here, we aimed to dissect the effect of cardiac injury on SCR in different regions in the intact LV myocardium using cryoinjury on rat living myocardial slices (LMS). We studied SCR under proarrhythmic conditions using a fluorescent Ca2+ indicator and high-resolution imaging in LMS from the subendocardium (ENDO) and subepicardium (EPI). Cryoinjury caused structural remodeling, with loss in T-tubule density and an increased time of Ca2+ transients to peak after injury. In ENDO LMS, the Ca2+ transient amplitude and decay phase were reduced, while these were not affected in EPI LMS after cryoinjury. The frequency of spontaneous whole-slice contractions increased in ENDO LMS without affecting EPI LMS after injury. Cryoinjury caused an increase in foci that generates SCR in both ENDO and EPI LMS. In ENDO LMS, SCRs were more closely distributed and had reduced latencies after cryoinjury, whereas this was not affected in EPI LMS. Inhibition of CaMKII reduced the number, distribution, and latencies of SCR, as well as whole-slice contractions in ENDO LMS, but not in EPI LMS after cryoinjury. Furthermore, CaMKII inhibition did not affect the excitation–contraction coupling in cryoinjured ENDO or EPI LMS. In conclusion, we demonstrate increased arrhythmogenic susceptibility in the injured ENDO. Our findings show involvement of CaMKII and highlight the need for region-specific targeting in cardiac therapies.
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Affiliation(s)
- Eef Dries
- National Heart and Lung Institute, Imperial College London, London, UK.,Lab of Experimental Cardiology, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Ifigeneia Bardi
- National Heart and Lung Institute, Imperial College London, London, UK
| | | | - Bram Meijlink
- National Heart and Lung Institute, Imperial College London, London, UK
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17
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Kim YG, Oh SK, Choi HY, Choi JI. Inherited arrhythmia syndrome predisposing to sudden cardiac death. Korean J Intern Med 2021; 36:527-538. [PMID: 33092314 PMCID: PMC8137412 DOI: 10.3904/kjim.2020.481] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 10/27/2020] [Indexed: 12/03/2022] Open
Abstract
Inherited arrhythmia (IA) is one of the main causes of sudden cardiac death (SCD) in young people, and is reported to be a more prevalent cause of SCD in Asia than in Western countries. IAs are a group of genetic disorders caused by mutations in genes encoding cardiac ion channels, leading to electrophysiological characteristics that often occur in the absence of structural abnormalities. Channelopathies, such as long QT syndrome and Brugada syndrome, carry a potential risk of life-threatening ventricular tachyarrhythmias that predispose to SCD, although early prediction and prevention of the risk remain challenging. Recent advances in genetic testing have facilitated risk stratification as well as a precise diagnosis for IA, despite ongoing debates about the implications. Herein, we provide epidemiological data, a pathophysiological overview, and the current clinical approach to IAs related to SCD. In addition, we review the general issues arising from genetic testing for IAs.
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Affiliation(s)
- Yun Gi Kim
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - Suk-Kyu Oh
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - Ha Young Choi
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - Jong-Il Choi
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
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18
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Sampedro-Puente DA, Raphel F, Fernandez-Bes J, Laguna P, Lombardi D, Pueyo E. Characterization of Spatio-Temporal Cardiac Action Potential Variability at Baseline and Under β-Adrenergic Stimulation by Combined Unscented Kalman Filter and Double Greedy Dimension Reduction. IEEE J Biomed Health Inform 2021; 25:276-288. [PMID: 32248135 DOI: 10.1109/jbhi.2020.2984647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Elevated spatio-temporal variability of human ventricular repolarization has been related to increased risk for ventricular arrhythmias and sudden cardiac death, particularly under β-adrenergic stimulation ( β-AS). This work presents a methodology for theoretical characterization of temporal and spatial repolarization variability at baseline conditions and in response to β-AS. For any measured voltage trace, the proposed methodology estimates the parameters and state variables of an underlying human ventricular action potential (AP) model by combining Double Greedy Dimension Reduction (DGDR) with automatic selection of biomarkers and the Unscented Kalman Filter (UKF). Such theoretical characterization can facilitate subsequent characterization of underlying variability mechanisms. MATERIAL AND METHODS Given an AP trace, initial estimates for the ionic conductances in a stochastic version of the baseline human ventricular O'Hara et al. model were obtained by DGDR. Those estimates served to initialize and update model parameter estimates by the UKF method based on formulation of an associated nonlinear state-space representation and joint estimation of model parameters and state variables. Similarly, β-AS-induced phosphorylation levels of cellular substrates were estimated by the DGDR-UKF methodology. Performance was tested by building an experimentally-calibrated population of virtual cells, from which synthetic AP traces were generated for baseline and β-AS conditions. RESULTS The combined DGDR-UKF methodology led to 25% reduction in the error associated with estimation of ionic current conductances at baseline conditions and phosphorylation levels under β-AS with respect to individual DGDR and UKF methods. This improvement was not at the expense of higher computational load, which was diminished by 90% with respect to the individual UKF method. Both temporal and spatial AP variability of repolarization were accurately characterized by the DGDR-UKF methodology. CONCLUSIONS A combined DGDR-UKF methodology is proposed for parameter and state variable estimation of human ventricular cell models from available AP traces at baseline and under β-AS. This methodology improves the estimation performance and reduces the convergence time with respect to individual DGDR and UKF methods and renders a suitable approach for computational characterization of spatio-temporal repolarization variability to be used for ascertainment of variability mechanisms and its relation to arrhythmogenesis.
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19
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Arrhythmia Mechanisms in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. J Cardiovasc Pharmacol 2020; 77:300-316. [PMID: 33323698 DOI: 10.1097/fjc.0000000000000972] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/08/2020] [Indexed: 12/30/2022]
Abstract
ABSTRACT Despite major efforts by clinicians and researchers, cardiac arrhythmia remains a leading cause of morbidity and mortality in the world. Experimental work has relied on combining high-throughput strategies with standard molecular and electrophysiological studies, which are, to a great extent, based on the use of animal models. Because this poses major challenges for translation, the progress in the development of novel antiarrhythmic agents and clinical care has been mostly disappointing. Recently, the advent of human induced pluripotent stem cell-derived cardiomyocytes has opened new avenues for both basic cardiac research and drug discovery; now, there is an unlimited source of cardiomyocytes of human origin, both from healthy individuals and patients with cardiac diseases. Understanding arrhythmic mechanisms is one of the main use cases of human induced pluripotent stem cell-derived cardiomyocytes, in addition to pharmacological cardiotoxicity and efficacy testing, in vitro disease modeling, developing patient-specific models and personalized drugs, and regenerative medicine. Here, we review the advances that the human induced pluripotent stem cell-derived-based modeling systems have brought so far regarding the understanding of both arrhythmogenic triggers and substrates, while also briefly speculating about the possibilities in the future.
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20
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Bazmi M, Escobar AL. Excitation-Contraction Coupling in the Goldfish ( Carassius auratus) Intact Heart. Front Physiol 2020; 11:1103. [PMID: 33041845 PMCID: PMC7518121 DOI: 10.3389/fphys.2020.01103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/10/2020] [Indexed: 12/17/2022] Open
Abstract
Cardiac physiology of fish models is an emerging field given the ease of genome editing and the development of transgenic models. Several studies have described the cardiac properties of zebrafish (Denio rerio). The goldfish (Carassius auratus) belongs to the same family as the zebrafish and has emerged as an alternative model with which to study cardiac function. Here, we propose to acutely study electrophysiological and systolic Ca2+ signaling in intact goldfish hearts. We assessed the Ca2+ dynamics and the electrophysiological cardiac function of goldfish, zebrafish, and mice models, using pulsed local field fluorescence microscopy, intracellular microelectrodes, and flash photolysis in perfused hearts. We observed goldfish ventricular action potentials (APs) and Ca2+ transients to be significantly longer when compared to the zebrafish. The action potential half duration at 50% (APD50) of goldfish was 370.38 ± 8.8 ms long, and in the zebrafish they were observed to be only 83.9 ± 9.4 ms. Additionally, the half duration of the Ca2+ transients was also longer for goldfish (402.1 ± 4.4 ms) compared to the zebrafish (99.1 ± 2.7 ms). Also, blocking of the L-type Ca2+ channels with nifedipine revealed this current has a major role in defining the amplitude and the duration of goldfish Ca2+ transients. Interestingly, nifedipine flash photolysis experiments in the intact heart identified whether or not the decrease in the amplitude of Ca2+ transients was due to shorter APs. Moreover, an increase in temperature and heart rate had a strong shortening effect on the AP and Ca2+ transients of goldfish hearts. Furthermore, ryanodine (Ry) and thapsigargin (Tg) significantly reduced the amplitude of the Ca2+ transients, induced a prolongation in the APs, and altogether exhibited the degree to which the Ca2+ release from the sarcoplasmic reticulum contributed to the Ca2+ transients. We conclude that the electrophysiological properties and Ca2+ signaling in intact goldfish hearts strongly resembles the endocardial layer of larger mammals.
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Affiliation(s)
- Maedeh Bazmi
- Quantitative Systems Biology Program, School of Natural Sciences, University of California, Merced, Merced, CA, United States
| | - Ariel L Escobar
- Department of Bioengineering, School of Engineering, University of California, Merced, Merced, CA, United States
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21
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Michalek P, Hatahet SB, Svetlosak M, Margitfalvi P, Waczulikova I, Trnovec S, Böhm A, Benacka O, Hatala R. No Association Between T-peak to T-end Interval on the Resting ECG and Long-Term Incidence of Ventricular Arrhythmias Triggering ICD Interventions. Front Physiol 2020; 11:1115. [PMID: 32982802 PMCID: PMC7488192 DOI: 10.3389/fphys.2020.01115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/11/2020] [Indexed: 11/15/2022] Open
Abstract
Background and Objectives Potential of using the T-peak to T-end (TpTe) interval as an electrocardiographic parameter reflecting the transmural dispersion of ventricular repolarization (TDR) to identify patients (pts.) with higher risk of malignant ventricular arrhythmias (MVA) for better selection of candidates for implantable cardioverter-defibrillator (ICD) in primary prevention (PP) of sudden cardiac death (SCD) remains controversial. The primary objective of this study was to investigate the relationship between the TpTe interval in patient’s preimplantation resting 12-lead electrocardiogram (ECG) and the incidence of MVA resulting in appropriate ICD intervention (AI). The secondary objective was to assess its relationship to overall mortality. Methods A total of 243 consecutive pts. with severe left ventricular (LV) systolic dysfunction after myocardial infarction (MI) with a single-chamber ICD for PP of SCD from one implantation center were included. Excluded were all pts. with any other disease that could interfere with the indication of ICD implantation. Primarily investigated intervals were measured manually in accordance with accepted methodology. Data on ICD interventions were acquired from device interrogation during regular outpatient visits. Survival data were collected from the databases of health insurance and regulatory authorities. Results We did not find a significant relationship between the duration of the TpTe interval and the incidence of MVA (71.5 ms in pts. with MVA vs. 70 ms in pts. without MVA; p = 0.408). Similar results were obtained for the corrected TpTe interval (TpTec) and the ratio of TpTe to QT interval (76.3 ms vs. 76.5 ms; p = 0.539 and 0.178 vs. 0.181; p = 0.547, respectively). There was also no significant difference between the duration of TpTe, TpTec and TpTe/QT ratio in pts. groups by overall mortality (71.5 ms in the deceased group vs. 70 ms in the survivors group; HR 1.01; 95% CI, 0.99–1.02; p = 0.715, 76.3 ms vs. 76.5 ms; HR 1.01; 95% CI, 0.99–1.02; p = 0.208 and 0.178 vs. 0.186; p = 0.116, respectively). Conclusion This study suggests no significant association of overall or MVA-free survival with ECG parameters reflecting TDR (TpTe, TpTec) in patients with systolic dysfunction after MI and ICD implanted for primary prevention.
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Affiliation(s)
- Peter Michalek
- Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | | | - Martin Svetlosak
- Department of Arrhythmias and Cardiac Pacing, The National Institute of Cardiovascular Diseases, Bratislava, Slovakia
| | - Peter Margitfalvi
- Department of Arrhythmias and Cardiac Pacing, The National Institute of Cardiovascular Diseases, Bratislava, Slovakia
| | - Iveta Waczulikova
- Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Bratislava, Slovakia
| | - Sebastian Trnovec
- Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Allan Böhm
- Faculty of Medicine, Slovak Medical University in Bratislava, Bratislava, Slovakia.,Department of Acute Cardiology, The National Institute of Cardiovascular Diseases, Bratislava, Slovakia
| | - Ondrej Benacka
- Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia.,Department of Arrhythmias and Cardiac Pacing, The National Institute of Cardiovascular Diseases, Bratislava, Slovakia
| | - Robert Hatala
- Faculty of Medicine, Slovak Medical University in Bratislava, Bratislava, Slovakia.,Department of Arrhythmias and Cardiac Pacing, The National Institute of Cardiovascular Diseases, Bratislava, Slovakia
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Blok M, Boukens BJ. Mechanisms of Arrhythmias in the Brugada Syndrome. Int J Mol Sci 2020; 21:ijms21197051. [PMID: 32992720 PMCID: PMC7582368 DOI: 10.3390/ijms21197051] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 12/13/2022] Open
Abstract
Arrhythmias in Brugada syndrome patients originate in the right ventricular outflow tract (RVOT). Over the past few decades, the characterization of the unique anatomy and electrophysiology of the RVOT has revealed the arrhythmogenic nature of this region. However, the mechanisms that drive arrhythmias in Brugada syndrome patients remain debated as well as the exact site of their occurrence in the RVOT. Identifying the site of origin and mechanism of Brugada syndrome would greatly benefit the development of mechanism-driven treatment strategies.
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Affiliation(s)
- Michiel Blok
- Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Bastiaan J. Boukens
- Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Correspondence: ; Tel.: +31-(0)20-566-4659
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Saadeh K, Shivkumar K, Jeevaratnam K. Targeting the β-adrenergic receptor in the clinical management of congenital long QT syndrome. Ann N Y Acad Sci 2020; 1474:27-46. [PMID: 32901453 DOI: 10.1111/nyas.14425] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/10/2020] [Accepted: 06/09/2020] [Indexed: 01/01/2023]
Abstract
The long QT syndrome (LQTS) is largely treated pharmacologically with β-blockers, despite the role of sympathetic activity in LQTS being poorly understood. Using the trigger-substrate model of cardiac arrhythmias in this review, we amalgamate current experimental and clinical data from both animal and human studies to explain the mechanism of adrenergic stimulation and blockade on LQT arrhythmic risk and hence assess the efficacy of β-adrenoceptor blockade in the management of LQTS. In LQTS1 and LQTS2, sympathetic stimulation increases arrhythmic risk by enhancing early afterdepolarizations and transmural dispersion of repolarization. β-Blockers successfully reduce cardiac events by reducing these triggers and substrates; however, these effects are less marked in LQTS2 compared with LQTS1. In LQTS3, clinical and experimental investigations of the effects of sympathetic stimulation and β-blocker use have produced contradictory findings, resulting in significant clinical uncertainty. We offer explanations for these contradicting results relating to study sample size, the dose of the β-blocker administered associated with its off-target Na+ channel effects, as well as the type of β-blocker used. We conclude that the antiarrhythmic efficacy of β-blockers is a genotype-specific phenomenon, and hence the use of β-blockers in clinical practice should be genotype dependent.
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Affiliation(s)
- Khalil Saadeh
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Centre, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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Gul S, Yontar OC, Yenercag M, Seker OO, Erdogan G, Arslan U. Effect of angiotensin/neprilysin inhibition on ventricular repolarization and clinical arrhythmogenesis. CARDIO-IT 2020. [DOI: 10.15275/cardioit.2020.0103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background: The most common reason for sudden cardiac death in heart failure is malign ventricular arrhythmias. LCZ 696 improves hospitalization and sudden cardiac death outcomes in heart failure, however mechanisms in preventing sudden cardiac death are still unknown. There is little information available assessing effect of LCZ 696 on Tp-e interval and related calculations. In this study, we aimed to investigate the impact of Sacubitril/valsartan therapy on Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio in heart failure patients and its reflections on clinical arrhythmogenesis. Methods: The study was designed as a prospective observational fashion. 265 patients with implantable cardioverter-defibrillator (ICD), who were on regular follow up at Samsun Training and Research Hospital Outpatient Heart Failure Clinic, were validated for the study. Clinical, echocardiographic, electrocardiogram and device data before initiation and six months after dose optimizing were obtained. Results: Stroke volume, cardiac output and ejection fraction significantly improved after LCZ 696 treatment. T wave related parameters, QT and QTC intervals significantly diminished. Furthermore, there was a negative correlation between baseline Tp-e interval duration and the absolute percentile increase of stroke volume(r:-0.234, p: 0.042) and cardiac output (r: -0.240, p: 0.037). Conclusion: In our study, switching Renin-Angiotensin-Aldosterone-System inhibitor with Angiotensin receptor/neprilysin inhibitor was associated with increase in left ventricle performance and decrease of sustained ventricular arrhythmias that required ICD shocks. These positive findings were accompanied by improvements in surface electrocaridogram changes such as Tp-e and related indices.
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Affiliation(s)
- Sefa Gul
- Samsun training and Research Hospital
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25
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Chen XM, Fan J, Cheng YJ, Ji CC, Yao FJ, Wu SH. Autonomic Influences Related to Early Repolarization in Patients Without Structural Heart Disease. J Cardiovasc Transl Res 2020; 13:970-976. [PMID: 32557319 DOI: 10.1007/s12265-020-10033-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/19/2020] [Indexed: 10/24/2022]
Abstract
This cross-sectional study focused on the association between heart rate variability (HRV) and early repolarization pattern (ERP). It included 1236 patients categorized into three groups: ERP type 1: J-point elevation with notched/slurred QRS; ERP type 2: ST elevation without dominant J-wave; and non-ERP group. Analyzing time-domain indexes include standard deviation of NN (normal-to-normal) RR intervals (SDNN), root mean square of successive difference in NN RR intervals (RMSSD), and proportion of consecutive NN intervals that differ by more than 50 ms (PNN50), there were significant differences between any two groups (all P < 0.01). All time-domain indexes showed: ERP type 2 > ERP type 1 > non-ERP. Multivariate logistic regression analysis revealed that SDNN at nighttime and gender were independently associated with the maximum magnitude of J-point elevation ≧ 0.2 mV. The findings strongly suggested that based on electrocardiogram characteristics, parasympathetic tone denoted by HRV may be related to different types of ERP.
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Affiliation(s)
- Xu-Miao Chen
- Department of Cardiology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Assisted Circulation, NHC, Guangzhou, China
| | - Jun Fan
- Department of Cardiology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Assisted Circulation, NHC, Guangzhou, China
| | - Yun-Jiu Cheng
- Department of Cardiology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Assisted Circulation, NHC, Guangzhou, China
| | - Cheng-Cheng Ji
- Department of Cardiology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Assisted Circulation, NHC, Guangzhou, China
| | - Feng-Juan Yao
- Department of Cardiology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Assisted Circulation, NHC, Guangzhou, China
| | - Su-Hua Wu
- Department of Cardiology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China. .,Key Laboratory of Assisted Circulation, NHC, Guangzhou, China.
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26
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Roden DM. A current understanding of drug-induced QT prolongation and its implications for anticancer therapy. Cardiovasc Res 2020; 115:895-903. [PMID: 30689740 DOI: 10.1093/cvr/cvz013] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/18/2018] [Accepted: 01/16/2019] [Indexed: 01/08/2023] Open
Abstract
The QT interval, a global index of ventricular repolarization, varies among individuals and is influenced by diverse physiologic and pathophysiologic stimuli such as gender, age, heart rate, electrolyte concentrations, concomitant cardiac disease, and other diseases such as diabetes. Many drugs produce a small but reproducible effect on QT interval but in rare instances this is exaggerated and marked QT prolongation can provoke the polymorphic ventricular tachycardia 'torsades de pointes', which can cause syncope or sudden cardiac death. The generally accepted common mechanism whereby drugs prolong QT is block of a key repolarizing potassium current in heart, IKr, generated by expression of KCNH2, also known as HERG. Thus, evaluation of the potential that a new drug entity may cause torsades de pointes has relied on exposure of normal volunteers or patients to drug at usual and high concentrations, and on assessment of IKr block in vitro. More recent work, focusing on anticancer drugs with QT prolonging liability, is defining new pathways whereby drugs can prolong QT. Notably, the in vitro effects of some tyrosine kinase inhibitors to prolong cardiac action potentials (the cellular correlate of QT) can be rescued by intracellular phosphatidylinositol 3,4,5-trisphosphate, the downstream effector of phosphoinositide 3-kinase. This finding supports a role for inhibition of this enzyme, either directly or by inhibition of upstream kinases, to prolong QT through mechanisms that are being worked out, but include enhanced inward 'late' sodium current during the plateau of the action potential. The definition of non-IKr-dependent pathways to QT prolongation will be important for assessing risk, not only with anticancer therapies but also with other QT prolonging drugs and for generating a refined understanding how variable activity of intracellular signalling systems can modulate QT and associated arrhythmia risk.
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Affiliation(s)
- Dan M Roden
- Department of Medicine, Vanderbilt University Medical Center, 2215B Garland Avenue, Room 1285B, Nashville, TN, USA.,Department of Pharmacology, Vanderbilt University Medical Center, 2215B Garland Avenue, Room 1285B, Nashville, TN, USA.,Department of Biomedical Informatics, Vanderbilt University Medical Center, 2215B Garland Avenue, Room 1285B, Nashville, TN, USA
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27
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Zimik S, Pandit R, Majumder R. Anisotropic shortening in the wavelength of electrical waves promotes onset of electrical turbulence in cardiac tissue: An in silico study. PLoS One 2020; 15:e0230214. [PMID: 32168323 PMCID: PMC7069633 DOI: 10.1371/journal.pone.0230214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/24/2020] [Indexed: 12/03/2022] Open
Abstract
Several pathological conditions introduce spatial variations in the electrical properties of cardiac tissue. These variations occur as localized or distributed gradients in ion-channel functionality over extended tissue media. Electrical waves, propagating through such affected tissue, demonstrate distortions, depending on the nature of the ionic gradient in the diseased substrate. If the degree of distortion is large, reentrant activity may develop, in the form of rotating spiral (2d) and scroll (3d) waves of electrical activity. These reentrant waves are associated with the occurrence of lethal cardiac rhythm disorders, known as arrhythmias, such as ventricular tachycardia (VT) and ventricular fibrillation (VF), which are believed to be common precursors of sudden cardiac arrest. By using state-of-the-art mathematical models for generic, and ionically-realistic (human) cardiac tissue, we study the detrimental effects of these ionic gradients on electrical wave propagation. We propose a possible mechanism for the development of instabilities in reentrant wave patterns, in the presence of ionic gradients in cardiac tissue, which may explain how one type of arrhythmia (VT) can degenerate into another (VF). Our proposed mechanism entails anisotropic reduction in the wavelength of the excitation waves because of anisotropic variation in its electrical properties, in particular the action potential duration (APD). We find that the variation in the APD, which we induce by varying ion-channel conductances, imposes a spatial variation in the spiral- or scroll-wave frequency ω. Such gradients in ω induce anisotropic shortening of wavelength of the spiral or scroll arms and eventually leads to instabilitites.
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Affiliation(s)
- Soling Zimik
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
| | - Rahul Pandit
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India
| | - Rupamanjari Majumder
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
- * E-mail:
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28
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Szabó Z, Ujvárosy D, Ötvös T, Sebestyén V, Nánási PP. Handling of Ventricular Fibrillation in the Emergency Setting. Front Pharmacol 2020; 10:1640. [PMID: 32140103 PMCID: PMC7043313 DOI: 10.3389/fphar.2019.01640] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 12/16/2019] [Indexed: 12/11/2022] Open
Abstract
Ventricular fibrillation (VF) and sudden cardiac death (SCD) are predominantly caused by channelopathies and cardiomyopathies in youngsters and coronary heart disease in the elderly. Temporary factors, e.g., electrolyte imbalance, drug interactions, and substance abuses may play an additive role in arrhythmogenesis. Ectopic automaticity, triggered activity, and reentry mechanisms are known as important electrophysiological substrates for VF determining the antiarrhythmic therapies at the same time. Emergency need for electrical cardioversion is supported by the fact that every minute without defibrillation decreases survival rates by approximately 7%–10%. Thus, early defibrillation is an essential part of antiarrhythmic emergency management. Drug therapy has its relevance rather in the prevention of sudden cardiac death, where early recognition and treatment of the underlying disease has significant importance. Cardioprotective and antiarrhythmic effects of beta blockers in patients predisposed to sudden cardiac death were highlighted in numerous studies, hence nowadays these drugs are considered to be the cornerstones of the prevention and treatment of life-threatening ventricular arrhythmias. Nevertheless, other medical therapies have not been proven to be useful in the prevention of VF. Although amiodarone has shown positive results occasionally, this was not demonstrated to be consistent. Furthermore, the potential proarrhythmic effects of drugs may also limit their applicability. Based on these unfavorable observations we highlight the importance of arrhythmia prevention, where echocardiography, electrocardiography and laboratory testing play a significant role even in the emergency setting. In the following we provide a summary on the latest developments on cardiopulmonary resuscitation, and the evaluation and preventive treatment possibilities of patients with increased susceptibility to VF and SCD.
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Affiliation(s)
- Zoltán Szabó
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Dóra Ujvárosy
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Doctoral School of Health Sciences, Faculty of Public Health, University of Debrecen, Debrecen, Hungary
| | - Tamás Ötvös
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Doctoral School of Health Sciences, Faculty of Public Health, University of Debrecen, Debrecen, Hungary
| | - Veronika Sebestyén
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Doctoral School of Health Sciences, Faculty of Public Health, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
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29
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Li KHC, Lee S, Yin C, Liu T, Ngarmukos T, Conte G, Yan GX, Sy RW, Letsas KP, Tse G. Brugada syndrome: A comprehensive review of pathophysiological mechanisms and risk stratification strategies. IJC HEART & VASCULATURE 2020; 26:100468. [PMID: 31993492 PMCID: PMC6974766 DOI: 10.1016/j.ijcha.2020.100468] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 01/01/2020] [Accepted: 01/02/2020] [Indexed: 12/17/2022]
Abstract
Brugada syndrome (BrS) is an inherited ion channel channelopathy predisposing to ventricular arrhythmias and sudden cardiac death. Originally believed to be predominantly associated with mutations in SCN5A encoding for the cardiac sodium channel, mutations of 18 genes other than SCN5A have been implicated in the pathogenesis of BrS to date. Diagnosis is based on the presence of a spontaneous or drug-induced coved-type ST segment elevation. The predominant electrophysiological mechanism underlying BrS remains disputed, commonly revolving around the three main hypotheses based on abnormal repolarization, depolarization or current-load match. Evidence from computational modelling, pre-clinical and clinical studies illustrates that molecular abnormalities found in BrS lead to alterations in excitation wavelength (λ), which ultimately elevates arrhythmic risk. A major challenge for clinicians in managing this condition is the difficulty in predicting the subset of patients who will suffer from life-threatening ventricular arrhythmic events. Several repolarization risk markers have been used thus far, but these neglect the contributions of conduction abnormalities in the form of slowing and dispersion. Indices incorporating both repolarization and conduction based on the concept of λ have recently been proposed. These may have better predictive values than the existing markers. Current treatment options include pharmacological therapy to reduce the occurrence of arrhythmic events or to abort these episodes, and interventions such as implantable cardioverter-defibrillator insertion or radiofrequency ablation of abnormal arrhythmic substrate.
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Affiliation(s)
- Ka Hou Christien Li
- Faculty of Medicine, Newcastle University, Newcastle, United Kingdom.,Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, SAR, PR China
| | - Sharen Lee
- Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, SAR, PR China
| | - Chengye Yin
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China
| | - Tachapong Ngarmukos
- Department of Medicine Faculty of Medicine Ramathibodi Hospital Mahidol University, Bangkok, Thailand
| | - Giulio Conte
- Division of Cardiology, Cardiocentro Ticino, Lugano, Switzerland
| | - Gan-Xin Yan
- Lankenau Institute for Medical Research and Lankenau Medical Center, Wynnewood, PA, USA
| | - Raymond W Sy
- Department of Cardiology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.,Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
| | - Konstantinos P Letsas
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Gary Tse
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China.,Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
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30
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Imnadze G, Zerm T. Prevention of ventricular fibrillation through de-networking of the Purkinje system: Proof-of-Concept Paper on the Substrate Modification of the Purkinje Network. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2019; 42:1285-1290. [PMID: 31424573 PMCID: PMC6852399 DOI: 10.1111/pace.13782] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/02/2019] [Accepted: 07/18/2019] [Indexed: 01/01/2023]
Abstract
Introduction Sudden cardiac death from ventricular fibrillation (VF) remains a major health problem worldwide. Currently, there are limited treatment options available to patients who suffer from episodes of VF. Because Purkinje fibers have been implicated as a source of initiation of VF, we are presenting the first paper of a series highlighting the promising results of substrate modulation through “De‐Networking” of the Purkinje system preventing VF in patients without an alternative ablation strategy. Methods and Results We studied 10 consecutive patients (two female) all but one implanted with an ICD with documented VF or fast polymorphic Ventricular tachycardia (VT) (five patients without history of structural heart disease, two with ischemic cardiomyopathy, one with hypertrophic obstructive cardiomyopathy, one with dilated cardiomyopathy, and one with aortic valve disease). After 3D electroanatomical mapping, the left bundle branch (LBB) and left ventricular Purkinje potentials were annotated creating a virtual triangle with the apex formed by the distal LBB and the base by the most distal Purkinje potentials. Linear radiofrequency catheter ablation at the base of the triangle was performed, followed by ablation within the virtual triangle sparing the LBB and both fascicles (“de‐networking”). All patients were treated without complications. During 1‐year follow‐up, only 2/10(20%) patients experienced recurrence in form of a single episode of polymorphic VT/VF. Conclusion Catheter ablation of VF through “de‐networking” of the Purkinje system in patients without overt arrhythmia substrate or trigger appears safe and effective and will require further study in a larger patient cohort.
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Affiliation(s)
- Guram Imnadze
- Heart and Diabetes Center North Rhine-Westphalia, Clinic of Arrhythmia Magnagement, Bad Oeynhausen, Nordrhein-Westfalen, DE.,Ruhr-Universitat Bochum Medizinische Fakultat, Arrhythmia Management, Bochum, Nordrhein-Westfalen, DE.,Department of Arrhythmia Management, Klinikum Osnabrueck, Osnabrueck, Germany
| | - Thomas Zerm
- Electrophysiology Department, Albertinen Hospital, Academic Teaching Hospital of the University of Hamburg - Eppendorf, Hamburg, Germany
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31
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Aguilar-Sanchez Y, Rodriguez de Yurre A, Argenziano M, Escobar AL, Ramos-Franco J. Transmural Autonomic Regulation of Cardiac Contractility at the Intact Heart Level. Front Physiol 2019; 10:773. [PMID: 31333477 PMCID: PMC6616252 DOI: 10.3389/fphys.2019.00773] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 06/03/2019] [Indexed: 01/14/2023] Open
Abstract
The relationship between cardiac excitability and contractility depends on when Ca2+ influx occurs during the ventricular action potential (AP). In mammals, it is accepted that Ca2+ influx through the L-type Ca2+ channels occurs during AP phase 2. However, in murine models, experimental evidence shows Ca2+ influx takes place during phase 1. Interestingly, Ca2+ influx that activates contraction is highly regulated by the autonomic nervous system. Indeed, autonomic regulation exerts multiple effects on Ca2+ handling and cardiac electrophysiology. In this paper, we explore autonomic regulation in endocardial and epicardial layers of intact beating mice hearts to evaluate their role on cardiac excitability and contractility. We hypothesize that in mouse cardiac ventricles the influx of Ca2+ that triggers excitation–contraction coupling (ECC) does not occur during phase 2. Using pulsed local field fluorescence microscopy and loose patch photolysis, we show sympathetic stimulation by isoproterenol increased the amplitude of Ca2+ transients in both layers. This increase in contractility was driven by an increase in amplitude and duration of the L-type Ca2+ current during phase 1. Interestingly, the β-adrenergic increase of Ca2+ influx slowed the repolarization of phase 1, suggesting a competition between Ca2+ and K+ currents during this phase. In addition, cAMP activated L-type Ca2+ currents before SR Ca2+ release activated the Na+-Ca2+ exchanger currents, indicating Cav1.2 channels are the initial target of PKA phosphorylation. In contrast, parasympathetic stimulation by carbachol did not have a substantial effect on amplitude and kinetics of endocardial and epicardial Ca2+ transients. However, carbachol transiently decreased the duration of the AP late phase 2 repolarization. The carbachol-induced shortening of phase 2 did not have a considerable effect on ventricular pressure and systolic Ca2+ dynamics. Interestingly, blockade of muscarinic receptors by atropine prolonged the duration of phase 2 indicating that, in isolated hearts, there is an intrinsic release of acetylcholine. In addition, the acceleration of repolarization induced by carbachol was blocked by the acetylcholine-mediated K+ current inhibition. Our results reveal the transmural ramifications of autonomic regulation in intact mice hearts and support our hypothesis that Ca2+ influx that triggers ECC occurs in AP phase 1 and not in phase 2.
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Affiliation(s)
- Yuriana Aguilar-Sanchez
- Department of Physiology and Biophysics, School of Medicine, Rush University Medical Center, Chicago, IL, United States
| | - Ainhoa Rodriguez de Yurre
- Laboratorio de Cardio Inmunologia, Instituto de Biofisica Carlos Chagas Filho, Rio de Janeiro, Brazil
| | - Mariana Argenziano
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Ariel L Escobar
- Department of Bioengineering, School of Engineering, University of California, Merced, Merced, CA, United States
| | - Josefina Ramos-Franco
- Department of Physiology and Biophysics, School of Medicine, Rush University Medical Center, Chicago, IL, United States
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32
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Pianca N, Di Bona A, Lazzeri E, Costantini I, Franzoso M, Prando V, Armani A, Rizzo S, Fedrigo M, Angelini A, Basso C, Pavone FS, Rubart M, Sacconi L, Zaglia T, Mongillo M. Cardiac sympathetic innervation network shapes the myocardium by locally controlling cardiomyocyte size through the cellular proteolytic machinery. J Physiol 2019; 597:3639-3656. [DOI: 10.1113/jp276200] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/21/2019] [Indexed: 01/07/2023] Open
Affiliation(s)
- Nicola Pianca
- Veneto Institute of Molecular Medicine Padova Italy
- Department of Biomedical SciencesUniversity of Padova Padova Italy
| | - Anna Di Bona
- Veneto Institute of Molecular Medicine Padova Italy
- Department of Cardiac, Thoracic, Vascular Sciences and Public HealthUniversity of Padova Padova Italy
| | - Erica Lazzeri
- European Laboratory for Non‐linear SpectroscopyUniversity of Florence Florence Italy
| | - Irene Costantini
- European Laboratory for Non‐linear SpectroscopyUniversity of Florence Florence Italy
- National Institute of Optics, National Research CouncilUniversity of Florence Florence Italy
| | - Mauro Franzoso
- Veneto Institute of Molecular Medicine Padova Italy
- Department of Biomedical SciencesUniversity of Padova Padova Italy
| | - Valentina Prando
- Veneto Institute of Molecular Medicine Padova Italy
- Department of Cardiac, Thoracic, Vascular Sciences and Public HealthUniversity of Padova Padova Italy
| | - Andrea Armani
- Veneto Institute of Molecular Medicine Padova Italy
- Department of Biomedical SciencesUniversity of Padova Padova Italy
| | - Stefania Rizzo
- Department of Cardiac, Thoracic, Vascular Sciences and Public HealthUniversity of Padova Padova Italy
| | - Marny Fedrigo
- Department of Cardiac, Thoracic, Vascular Sciences and Public HealthUniversity of Padova Padova Italy
| | - Annalisa Angelini
- Department of Cardiac, Thoracic, Vascular Sciences and Public HealthUniversity of Padova Padova Italy
| | - Cristina Basso
- Department of Cardiac, Thoracic, Vascular Sciences and Public HealthUniversity of Padova Padova Italy
| | - Francesco S. Pavone
- European Laboratory for Non‐linear SpectroscopyUniversity of Florence Florence Italy
- National Institute of Optics, National Research CouncilUniversity of Florence Florence Italy
- Department of Physics and AstronomyUniversity of Florence Florence Italy
| | - Michael Rubart
- Indiana University School of Medicine Indianapolis IN USA
| | - Leonardo Sacconi
- European Laboratory for Non‐linear SpectroscopyUniversity of Florence Florence Italy
- National Institute of Optics, National Research CouncilUniversity of Florence Florence Italy
| | - Tania Zaglia
- Veneto Institute of Molecular Medicine Padova Italy
- Department of Biomedical SciencesUniversity of Padova Padova Italy
- Department of Cardiac, Thoracic, Vascular Sciences and Public HealthUniversity of Padova Padova Italy
| | - Marco Mongillo
- Veneto Institute of Molecular Medicine Padova Italy
- Department of Biomedical SciencesUniversity of Padova Padova Italy
- CNR Institute of Neuroscience Padova Italy
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33
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Sampedro-Puente DA, Fernandez-Bes J, Virag L, Varro A, Pueyo E. Data-Driven Identification of Stochastic Model Parameters and State Variables: Application to the Study of Cardiac Beat-to-Beat Variability. IEEE J Biomed Health Inform 2019; 24:693-704. [PMID: 31180875 DOI: 10.1109/jbhi.2019.2921881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Enhanced spatiotemporal ventricular repolarization variability has been associated with ventricular arrhythmias and sudden cardiac death, but the involved mechanisms remain elusive. In this paper, a methodology for estimation of parameters and state variables of stochastic human ventricular cell models from input voltage data is proposed for investigation of repolarization variability. METHODS The proposed methodology formulates state-space representations based on developed stochastic cell models and uses the unscented Kalman filter to perform joint parameter and state estimation. Evaluation over synthetic and experimental data is presented. RESULTS Results on synthetically generated data show the ability of the methodology to: first, filter out measurement noise from action potential (AP) traces; second, identify model parameters and state variables from each of those individual AP traces, thus allowing robust characterization of cell-to-cell variability; and, third, replicate statistical population's distributions of input AP-based markers, including dynamic markers quantifying beat-to-beat variability. Application onto experimental data demonstrates the ability of the methodology to match input AP traces while concomitantly inferring the characteristics of underlying stochastic cell models. CONCLUSION A novel methodology is presented for estimation of parameters and hidden variables of stochastic cardiac computational models, with the advantage of providing a one-to-one match between each individual AP trace and a corresponding set of model characteristics. SIGNIFICANCE The proposed methodology can greatly help in the characterization of temporal (beat-to-beat) and spatial (cell-to-cell) variability in human ventricular repolarization and in ascertaining the corresponding underlying mechanisms, particularly in scenarios with limited available experimental data.
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34
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Park JI, Lim KM. Prediction of the mechanical response of cardiac alternans by using an electromechanical model of human ventricular myocytes. Biomed Eng Online 2019; 18:72. [PMID: 31174533 PMCID: PMC6555982 DOI: 10.1186/s12938-019-0690-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/27/2019] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Although the quantitative analysis of electromechanical alternans is important, previous studies have focused on electrical alternans, and there is a lack quantitative analysis of mechanical alternans at the subcellular level according to various basic cycle lengths (BCLs). Therefore, we used the excitation-contraction (E-C) coupling model of human ventricular cells to quantitatively analyze the mechanical alternans of ventricular cells according to various BCLs. METHODS To implement E-C coupling, we used calcium transient data, which is the output data of electrical simulation using the electrophysiological model of human ventricular myocytes, as the input data of mechanical simulation using the contractile myofilament dynamics model. Moreover, we applied various loads on ventricular cells for implementation of isotonic and isometric contraction. RESULTS As the BCL was reduced from 1000 to 200 ms at 30 ms increments, mechanical alternans, as well as electrical alternans, were observed. At this time, the myocardial diastolic tension increased, and the contractile ATP consumption rate remained greater than zero even in the resting state. Furthermore, the time of peak tension, equivalent cell length, and contractile ATP consumption rate were all reduced. There are two tendencies that endocardial, mid-myocardial, and epicardial cells have the maximum amplitude of tension and the peak systolic tension begins to appear at a high rate under the isometric condition at a particular BCL. CONCLUSIONS We observed mechanical alternans of ventricular myocytes as well as electrical alternans, and identified unstable conditions associated with mechanical alternans. We also determined the amount of BCL given to each ventricular cell to generate stable and high tension state in the case of isometric contraction.
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Affiliation(s)
- Jun Ik Park
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk, 39177, Republic of Korea
| | - Ki Moo Lim
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk, 39177, Republic of Korea.
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35
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Molina CE, Jacquet E, Ponien P, Muñoz-Guijosa C, Baczkó I, Maier LS, Donzeau-Gouge P, Dobrev D, Fischmeister R, Garnier A. Identification of optimal reference genes for transcriptomic analyses in normal and diseased human heart. Cardiovasc Res 2019; 114:247-258. [PMID: 29036603 DOI: 10.1093/cvr/cvx182] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 09/20/2017] [Indexed: 11/13/2022] Open
Abstract
Aims Quantitative real-time RT-PCR (RT-qPCR) has become the method of choice for mRNA quantification, but requires an accurate normalization based on the use of reference genes showing invariant expression across various pathological conditions. Only few data exist on appropriate reference genes for the human heart. The objective of this study was to determine a set of suitable reference genes in human atrial and ventricular tissues, from right and left cavities in control and in cardiac diseases. Methods and results We assessed the expression of 16 reference genes (ACTB, B2M, GAPDH, GUSB, HMBS, HPRT1, IPO8, PGK1, POLR2A, PPIA, RPLP0, TBP, TFRC, UBC, YWHAZ, 18S) in tissues from: right and left ventricles from healthy controls and heart failure (HF) patients; right-atrial tissue from patients in sinus rhythm with (SRd) or without (SRnd) atrial dilatation, patients with paroxysmal (pAF) or chronic (cAF) atrial fibrillation or with HF; and left-atrial tissue from patients in SR or cAF. Consensual analysis (by geNorm and Normfinder algorithms, BestKeeper software tool and comparative delta-Ct method) of the variability scores obtained for each reference gene expression shows that the most stably expressed genes are: GAPDH, GUSB, IPO8, POLR2A, and YWHAZ when comparing either right and left ventricle or ventricle from healthy controls and HF patients; GAPDH, IPO8, POLR2A, PPIA, and RPLP0 when comparing either right and left atrium or right atria from all pathological groups. ACTB, TBP, TFRC, and 18S genes were identified as the least stable. Conclusions The overall most stable reference genes across different heart cavities and disease conditions were GAPDH, IPO8, POLR2A and PPIA. YWHAZ or GUSB could be added to this set for some specific experiments. This study should provide useful guidelines for reference gene selection in RT-qPCR studies in human heart.
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Affiliation(s)
- Cristina E Molina
- Inserm, UMR-S 1180, University of Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France.,Institute of Pharmacology and Toxicology, Heart Research Center Göttingen, University Medical Center, Georg-August University Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Germany
| | - Eric Jacquet
- Institut de Chimie des Substances Naturelles, UPR 2301, CNRS, University of Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Prishila Ponien
- Institut de Chimie des Substances Naturelles, UPR 2301, CNRS, University of Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | - Istvan Baczkó
- Department Pharmacology and Pharmacotherapy, University of Szeged, Hungary
| | - Lars S Maier
- Department Internal Medicine II, University Heart Center, University Hospital Regensburg, Regensburg, Germany
| | | | - Dobromir Dobrev
- West German Heart and Vascular Center, Institute of Pharmacology, University Duisburg-Essen, Essen, Germany
| | - Rodolphe Fischmeister
- Inserm, UMR-S 1180, University of Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - Anne Garnier
- Inserm, UMR-S 1180, University of Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
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Son O, Boduroglu Y. Comparing of Tp-Te Interval and Tp-Te/Qt Ratio in Patients with Preserved, Mid-Range and Reduced Ejection Fraction Heart Failure. Open Access Maced J Med Sci 2019; 7:752-759. [PMID: 30962833 PMCID: PMC6447328 DOI: 10.3889/oamjms.2019.186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Heart failure (HF) is classified in three class: HF with preserved EF (HFpEF); normal or LVEF ≥ 50%, HF with reduced EF (HFrEF); LEVF < 40% and newly HF mid-range EF (HFmrEF); LVEF 40-49%. On Electrocardiography (ECG) T wave, Tpeak-Tend (Tp-Te) interval reflects transmural dispersion of repolarisation (TDR) which of these indexes have been proposed as predictors of risk for ventricular arrhythmia (VA) in many cardiac diseases. AIM Aim of this study to asses these indices of TDR among three HF class. METHODS Total of 192 patients were included in this study. RESULTS Many of indices like Tp-Te, Tp-Te/QT wasn't different between groups (P > 0.05). But mean Q-Tpeak (QTp), S-Tend (S-Te) and S-Tpeak (S-Tp) were found significantly different between groups (P < 0.05). Again S-Te was found different according to having fragmented QRS (fQRS) on ECG (P = 0.031). Comparing to mitral inflow E/A parameters showed significant differences for Tp-Te, Tp-Tec, Tp-Te/QT, Tp-Te/QTc and Tp-Tec/QTc parameters. Finally, we found correlations between S-Te and white blood cell (WBC) (r = - 0.171; P = 0.037) and S-Tp and WBC (r = - 0.170; P = 0.038) and between S-Te and fQRS (r = 0.158; P = 0.031). CONCLUSIONS We didn't find differences for many of indices of TDR like Tp-Te interval between groups except QTp, S-Te, S-Tp intervals. Also, S-Te and fQRS showed significant correlation. For prediction of ventricular arrhythmia and cardiovascular death newer indexes on ECG are needed to be established in the future which will make us facilitate to distinguish high risk patients.
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Affiliation(s)
- Osman Son
- Department of Endocrinology, Private Acibadem Hospital, Eskisehir, Turkey
| | - Yalcin Boduroglu
- Department of Cardiology, Ahi Evran University Education and Research Hospital, Kirsehir, Turkey
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Santiago A, Aguado-Sierra J, Zavala-Aké M, Doste-Beltran R, Gómez S, Arís R, Cajas JC, Casoni E, Vázquez M. Fully coupled fluid-electro-mechanical model of the human heart for supercomputers. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3140. [PMID: 30117302 DOI: 10.1002/cnm.3140] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 04/28/2018] [Accepted: 07/22/2018] [Indexed: 05/12/2023]
Abstract
In this work, we present a fully coupled fluid-electro-mechanical model of a 50th percentile human heart. The model is implemented on Alya, the BSC multi-physics parallel code, capable of running efficiently in supercomputers. Blood in the cardiac cavities is modeled by the incompressible Navier-Stokes equations and an arbitrary Lagrangian-Eulerian (ALE) scheme. Electrophysiology is modeled with a monodomain scheme and the O'Hara-Rudy cell model. Solid mechanics is modeled with a total Lagrangian formulation for discrete strains using the Holzapfel-Ogden cardiac tissue material model. The three problems are simultaneously and bidirectionally coupled through an electromechanical feedback and a fluid-structure interaction scheme. In this paper, we present the scheme in detail and propose it as a computational cardiac workbench.
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Affiliation(s)
- Alfonso Santiago
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC), Barcelona, Spain
| | - Jazmín Aguado-Sierra
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC), Barcelona, Spain
| | - Miguel Zavala-Aké
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC), Barcelona, Spain
| | | | - Samuel Gómez
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC), Barcelona, Spain
| | - Ruth Arís
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC), Barcelona, Spain
| | - Juan C Cajas
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC), Barcelona, Spain
| | - Eva Casoni
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC), Barcelona, Spain
| | - Mariano Vázquez
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC), Barcelona, Spain
- Instituto de Investigación en Inteligencia Artificial (IIIA), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain
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Abstract
The aim of this study was to assess ventricular repolarization wave variations during the amiodarone treatment course for patients with ventricular arrhythmias and atrial fibrillation.Sixty-nine patients with ventricular arrhythmias and 9 patients with persistent atrial fibrillation were treated with intravenous injection of a 150 mg loading dose of amiodarone, followed by 1 mg/minute for 6 hours and 0.5 mg/minute for 48 hours. After the initial 24 hours of intravenous injection, amiodarone was also administered orally at a dose of 0.2 g tid for 1 week; followed by 0.2 g bid for 1 week and 0.2 g qd for maintenance. During the procedure, the heart rate, QT, QTc, QTd, QTcd TpTe, TpTe-c, TpTe-d, TpTe/QT, and QTp were measured on days 1, 3, 7, 10, 14, 17, and 20 of amiodarone treatment.The control rate of arrhythmias was 91.0% (71/78). The heart rate dropped significantly on the 7th day after treatment initiation and reached the minimal value on day 14. The QT interval was prolonged from day 3; TpTe was prolonged from day 7 to day 14; QTp was prolonged from day 1 to day 20. The longest QT interval (441.2 ± 33.9 ms) and TpTe (95.0 ± 18.0 ms) occurred on day 14. QTc, QTd, QTcd, TpTe-c, TpTe-d, and TpTe/QT showed no significant changes throughout the treatment.Amiodarone lowers the heart rate, prolongs QT and QTp intervals, and transiently prolongs TpTe. However, it has no effects on QTc, QTd, QTcd, TpTe-c, TpTe-d or TpTe/QT. Amiodarone prolongs QT interval evenly, showing no effects on repolarization dispersion. TpTe/QT is a better indicator of ventricular transmural repolarization dispersion compared with TpTe.
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Affiliation(s)
| | - Dingwei Gu
- Department of Orthopedic, North China University of Science and Technology Affiliated Hospital, Tangshan, Hebei, PR China
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Mačianskienė R, Martišienė I, Navalinskas A, Treinys R, Andriulė I, Jurevičius J. Mechanism of Action Potential Prolongation During Metabolic Inhibition in the Whole Rabbit Heart. Front Physiol 2018; 9:1077. [PMID: 30140239 PMCID: PMC6095129 DOI: 10.3389/fphys.2018.01077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/19/2018] [Indexed: 11/24/2022] Open
Abstract
Myocardial ischemia is associated with significant changes in action potential (AP) duration, which has a biphasic response to metabolic inhibition. Here, we investigated the mechanism of initial AP prolongation in whole Langendorff-perfused rabbit heart. We used glass microelectrodes to record APs transmurally. Simultaneously, optical AP, calcium transient (CaT), intracellular pH, and magnesium concentration changes were recorded using fluorescent dyes. The fluorescence signals were recorded using an EMCCD camera equipped with emission filters; excitation was induced by LEDs. We demonstrated that metabolic inhibition by carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP) resulted in AP shortening preceded by an initial prolongation and that there were no important differences in the response throughout the wall of the heart and in the apical/basal direction. AP prolongation was reduced by blocking the ICaL and transient outward potassium current (Ito) with diltiazem (DTZ) and 4-aminopyridine (4-AP), respectively. FCCP, an uncoupler of oxidative phosphorylation, induced reductions in CaTs and intracellular pH and increased the intracellular Mg2+ concentration. In addition, resting potential depolarization was observed, clearly indicating a decrease in the inward rectifier K+ current (IK1) that can retard AP repolarization. Thus, we suggest that the main currents responsible for AP prolongation during metabolic inhibition are the ICaL, Ito, and IK1, the activities of which are modulated mainly by changes in intracellular ATP, calcium, magnesium, and pH.
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Affiliation(s)
- Regina Mačianskienė
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Irma Martišienė
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Antanas Navalinskas
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Rimantas Treinys
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Inga Andriulė
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Jonas Jurevičius
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
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Zhang X, Liu ZQ, Singh D, Powell DK, Chung CS, Campbell KS, Wenk JF. Differential Effects of Isoproterenol on Regional Myocardial Mechanics in Rat using 3D cine DENSE Cardiovascular Magnetic Resonance. J Biomech Eng 2018; 141:2696750. [PMID: 30098173 DOI: 10.1115/1.4041042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Indexed: 01/03/2023]
Abstract
The present study assessed the acute effects of isoproterenol on left ventricular (LV) mechanics in healthy rats with the hypothesis that ß-adrenergic stimulation influences the mechanics of different myocardial regions of the LV wall in different ways. To accomplish this, magnetic resonance images were obtained in the LV of healthy rats with or without isoproterenol infusion. The LV contours were divided into basal, mid-ventricular, and apical regions. Additionally, the mid-ventricular myocardium was divided into three transmural layers with each layer partitioned into four segments (i.e., septal, inferior, lateral, and anterior). Peak systolic strains and torsion were quantified for each region. Isoproterenol significantly increased peak systolic radial strain and circumferential-longitudinal shear strain, as well as ventricular torsion, throughout the basal, mid-ventricle, and apical regions. In the mid-ventricle, isoproterenol significantly increased peak systolic radial strain, and induced significant increases in peak systolic circumferential strain and longitudinal strain in the septum. Isoproterenol consistently increased peak systolic circumferential-longitudinal shear strain in all mid-ventricular segments. Ventricular torsion was significantly increased in nearly all segments except the inferior sub-endocardium. The effects of isoproterenol on LV systolic mechanics (i.e., 3D strains and torsion) in healthy rats depend on the region. This region-dependency is also strain component-specific. These results provide insight into the regional response of LV mechanics to ß-adrenergic stimulation in rats, and could act as a baseline for future studies on subclinical abnormalities associated with the inotropic response in heart disease.
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Affiliation(s)
- Xiaoyan Zhang
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
| | - Zhan-Qiu Liu
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
| | - Dara Singh
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
| | - David K Powell
- Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY, USA
| | - Charles S Chung
- Department of Physiology, Wayne State University, Detroit, MI, USA; Department of Physiology, University of Kentucky, Lexington, KY, USA
| | | | - Jonathan F Wenk
- Department of Surgery, University of Kentucky, Lexington, KY, USA
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Nugraheni AP, Arso IA, Maharani E. Association of Tp-Te/QT Ratio With Ventricular Tachycardia in Patients With Idiopathic Outflow Tract Ventricular Premature Contraction. Cardiol Res 2018; 9:215-223. [PMID: 30116449 PMCID: PMC6089473 DOI: 10.14740/cr735w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 06/15/2018] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Idiopathic outflow tract ventricular premature contraction (VPC) can evolve into ventricular tachycardia (VT) via triggered activity mechanism. Transmural dispersion of repolarization (TDR) might play a role in idiopathic outflow tract VT by inducing phase 2 early afterdepolarization (EAD) and serve as the functional substrate for VT. Tp-Te/QT ratio as an arrhythmogenesis index has been reported to be associated with the incidence of ventricular arrhythmia. This study aims to investigate the association between Tp-Te/QT ratio with VT incidence in idiopathic outflow tract VPC. METHODS Observational research with cross sectional design was conducted. VT episodes were retrospectively tracked from electrocardiogram (ECG), treadmill test (TMT), Holter monitor and electrophysiology study data in Sardjito Hospital of patients with idiopathic outflow tract VPC during September to October 2017. Tp-Te/QT was defined as the time from the peak of T wave to the intersection between the tangent and isoeectric line, divided with QT interval. Tp-Te/QT ratio measurement was performed in leads V4, V5 and V6 by single observer. Tp-Te/QT ratio was categorized into increased (> 0.25) and normal (< 0.25). Chi-square and logistic regression test were performed. RESULTS Out of 46 patients, there were 28 patients who had VT. Increased Tp-Te/QT ratio of lead V4 was found in 11 patients, the increased ratios in leads V5 and V6 were found in 13 patients. The prevalence ratio (PR) of Tp-Te/QT ratio to VT incidence in lead V4 was 2.059 (95% CI: 1.464 - 2.895; P = 0.007), while in leads V5 and V6 was 2.200 (95% CI: 1.514 - 3.197; P = 0.002). Tp-Te/QT ratios in leads V4, V5 and V6 were not significantly different and equally strong in predicting VT events (P < 0.001; 95% CI). Adjustment of confounding factor hypertension with multivariate test gave insignificant results (PR: 1.290; 95% CI: 0.444 - 3.747). CONCLUSIONS Increased Tp-Te/QT ratio in idiopathic outflow tract VPC patients was associated with higher prevalence ratio for VT, although this was affected by hypertension. Leads V4, V5 and V6 were equally strong in predicting VT events.
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Affiliation(s)
- Arina Prihestri Nugraheni
- Department of Cardiology and Vascular Medicine, Faculty of Medicine, Universitas Gadjah Mada, Dr. Sardjito General Hospital, Yogyakarta, Indonesia
| | - Irsad Andi Arso
- Department of Cardiology and Vascular Medicine, Faculty of Medicine, Universitas Gadjah Mada, Dr. Sardjito General Hospital, Yogyakarta, Indonesia
| | - Erika Maharani
- Department of Cardiology and Vascular Medicine, Faculty of Medicine, Universitas Gadjah Mada, Dr. Sardjito General Hospital, Yogyakarta, Indonesia
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Tural Onur S, Emet S, Sokucu SN, Onur I. T wave peak-to-end interval in COPD. Int J Chron Obstruct Pulmon Dis 2018; 13:2157-2162. [PMID: 30034231 PMCID: PMC6049052 DOI: 10.2147/copd.s132538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Introduction The interval from the peak to the end of the electrocardiographic (ECG) T wave (Tp–Te) can estimate cardiovascular mortality and ventricular tachyarrhythmias. Objectives In this study, we aimed to define a new ECG parameter in patients with COPD. Methods This was a cross-sectional observational study that included COPD patients who were diagnosed previously and followed up in the outpatient clinic. All data of the patients’ demographic features, history, spirometry, and electrocardiographs were analyzed. Results We enrolled 134 patients with COPD and 40 healthy volunteers as controls in our study. Patients already known to be having COPD who were under follow-up for their COPD and diagnosed as having COPD according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria were included. Men comprised 82.8% of the COPD group and 73.2% of controls. The mean age in the COPD and control group was 60.2±9.4 and 58.2±6.7 years, respectively. There was no significant difference between the groups for age or sex (p=0.207, p=0.267, respectively). There were 46 (34.3%) patients in group A, 23 (17.2%) patients in group B, 26 (19.4%) patients in group C, and 46 (29.1%) patients in group D as COPD group. There was a significant increase in Tp–Te results in all precordial leads in the COPD group compared with the control group (p<0.05). Precordial V4 lead has the most extensive area under the curve (0.831; sensitivity 76.5%, specificity 89.6%). Conclusion We present strong evidence that Tp–Te intervals were increased in patients with COPD, which suggests that there may be an association between COPD and ventricular arrhythmias and cardiac morbidity.
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Affiliation(s)
- Seda Tural Onur
- Yedikule Chest Diseases and Thoracic Surgery Training and Research Hospital, Chest Disease, Zeytinburnu, Istanbul, Turkey,
| | - Samim Emet
- Department of Cardiology, Istanbul Faculty of Medicine, Istanbul University, Fatih, Istanbul, Turkey
| | - Sinem Nedime Sokucu
- Yedikule Chest Diseases and Thoracic Surgery Training and Research Hospital, Chest Disease, Zeytinburnu, Istanbul, Turkey,
| | - Imran Onur
- Department of Cardiology, Istanbul Faculty of Medicine, Istanbul University, Fatih, Istanbul, Turkey
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Vaverka J, Burša J, Šumbera J, Pásek M. Effect of Transmural Differences in Excitation-Contraction Delay and Contraction Velocity on Left Ventricle Isovolumic Contraction: A Simulation Study. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4798512. [PMID: 29862273 PMCID: PMC5971307 DOI: 10.1155/2018/4798512] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/01/2018] [Accepted: 03/13/2018] [Indexed: 12/14/2022]
Abstract
Recent studies have shown that left ventricle (LV) exhibits considerable transmural differences in active mechanical properties induced by transmural differences in electrical activity, excitation-contraction coupling, and contractile properties of individual myocytes. It was shown that the time between electrical and mechanical activation of myocytes (electromechanical delay: EMD) decreases from subendocardium to subepicardium and, on the contrary, the myocyte shortening velocity (MSV) increases in the same direction. To investigate the physiological importance of this inhomogeneity, we developed a new finite element model of LV incorporating the observed transmural gradients in EMD and MSV. Comparative simulations with the model showed that when EMD or MSV or both were set constant across the LV wall, the LV contractility during isovolumic contraction (IVC) decreased significantly ((dp/dt)max was reduced by 2 to 38% and IVC was prolonged by 18 to 73%). This was accompanied by an increase of transmural differences in wall stress. These results suggest that the transmural differences in EMD and MSV play an important role in physiological contractility of LV by synchronising the contraction of individual layers of ventricular wall during the systole. Reduction or enhancement of these differences may therefore impair the function of LV and contribute to heart failure.
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Affiliation(s)
- J Vaverka
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Faculty of Mechanical Engineering, University of Technology, Brno, Czech Republic
| | - J Burša
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Faculty of Mechanical Engineering, University of Technology, Brno, Czech Republic
| | - J Šumbera
- Department of Cardiovascular Diseases, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - M Pásek
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
- Institute of Thermomechanics, Czech Academy of Science, Prague, Czech Republic
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Zhao W, Lu G, Liu L, Sun Z, Wu M, Yi W, Chen H, Li Y, Tang L, Zeng J. Detection of Acute Myocardial Infarction in a Pig Model Using the SAN-Atrial-AVN-His (SAAH) Electrocardiogram (ECG), Model PHS-A10, an Automated and Integrated Signals Recognition System. MEDICAL SCIENCE MONITOR : INTERNATIONAL MEDICAL JOURNAL OF EXPERIMENTAL AND CLINICAL RESEARCH 2018; 24:1303-1309. [PMID: 29502127 PMCID: PMC5846368 DOI: 10.12659/msm.905961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The aim of this study was to compare the use of the standard 12-lead electrocardiogram (ECG) with the SAN-Atrial-AVN-His (SAAH) ECG (Model PHS-A10), a new automated and integrated signals recognition system that detects micro-waveforms within the P, QRS, and T-wave, in a pig model of acute myocardial infarction (MI). MATERIAL AND METHODS Six medium-sized domestic Chinese pigs underwent general anesthesia, and an angioplasty balloon was placed and dilated for 120 minutes in the first diagonal coronary artery arising from the left anterior descending (LAD) coronary artery. A standard ECG and a SAAH ECG (Model PHS-A10) were used to evaluate: 1) the number of wavelets in ST-T segment in lead V5; 2) the duration of the repolarization initial (Ri), or duration of the wavelets starting from the J-point to the endpoint of the wavelets in the ST interval; 3) the duration of the repolarization terminal (Rt), of the wavelets, starting from the endpoint of the wavelets in the ST interval to the cross-point of the T-wave and baseline; 4) the ratio Ri: Rt. RESULTS Following coronary artery occlusion, duration of Ri and Ri/Rt increased, and Rt decreased, which was detected by the SAAH ECG (Model PHS-A10) within 12 seconds, compared with standard ECG that detected ST segment depression at 24 seconds following coronary artery occlusion. CONCLUSIONS The findings from this preliminary study in a pig model of acute MI support the need for clinical studies to evaluate the SAAH ECG (Model PHS-A10) for the early detection of acute MI.
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Affiliation(s)
- Wenjiao Zhao
- Division of Cardiology, Xiangtan Central Hospital, Xiangtan, Hunan, China (mainland)
| | - Guihua Lu
- Division of Cardiology, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland)
| | - Li Liu
- Division of Cardiology, Xiangtan Central Hospital, Xiangtan, Hunan, China (mainland)
| | - Zhishan Sun
- Division of Cardiology, Xiangtan Central Hospital, Xiangtan, Hunan, China (mainland)
| | - Mingxin Wu
- Division of Cardiology, Xiangtan Central Hospital, Xiangtan, Hunan, China (mainland)
| | - Wenyan Yi
- Division of Cardiology, Xiangtan Central Hospital, Xiangtan, Hunan, China (mainland)
| | - Haiyan Chen
- Division of Cardiology, Xiangtan Central Hospital, Xiangtan, Hunan, China (mainland)
| | - Yanhui Li
- Division of Cardiology, Tongji Hospital Affiliated to Huazhong Technology, University Wuhan, Wuhan, Hubei, China (mainland)
| | - Lilong Tang
- Division of Cardiology, Xiangtan Central Hospital, Xiangtan, Hunan, China (mainland)
| | - Jianping Zeng
- Division of Cardiology, Xiangtan Central Hospital, Xiangtan, Hunan, China (mainland)
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Conlon R, Tanner R, David S, Szeplaki G, Galvin J, Keaney J, Keelan E, Boles U. Evaluation of the Tp-Te Interval, QTc and P-Wave Dispersion in Patients With Coronary Artery Ectasia. Cardiol Res 2018; 8:280-285. [PMID: 29317970 PMCID: PMC5755659 DOI: 10.14740/cr631w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 11/30/2017] [Indexed: 11/21/2022] Open
Abstract
Background Coronary artery ectasia (CAE) is defined as a diffuse dilatation of the diameter of the ectatic segment of the coronary artery, 1.5 times greater than that of the adjacent segment. The Tp-Te interval, P-wave and QTc dispersions are relatively new electrocardiographic markers associated with an increased risk of developing arrhythmias. Despite CAE increasing in prevalence in recent years, there is a sparsity of data available about its arrhythmogenic effect. The aim of the study was to evaluate QTc, P-wave dispersion and Tp-Te and Tp-Te/QT ratio in patients with CAE. Methods A retrospective comparative study was designed for consecutive age- and sex-matched patients. Twenty patients with isolated CAE (group 1) and 20 control subjects (group 2), with normal coronary arteries, were included. All patients presented with chest pain and coronary angiogram was indicated. Outcome measures included Tp-Te interval, Tp-Te/QT ratio, QTc dispersion and P-wave dispersion. Measurement of electrocardiogram (ECG) parameters was conducted using standardized digital online software. Descriptive and inferential statistics were performed. Results Mean Tp-Te (95.5 ± 9.01 ms) and Tp-Te/QT ratio (0.22 ± 0.02) were significantly prolonged in CAE group (Tp-Te: 84 ± 5.62 ms, P = 0.00009; Tp-Te/QT ratio: 0.20 ± 0.01, P = 0.00004). In addition, QTc (31.2 ± 3.71 ms) and P-wave dispersion (31.9 ± 5.46 ms) were significantly increased in comparison to the control group (QTc: 27.6 ± 2.82 ms, P = 0.00532 and 20 ± 3.77 ms, P = 0.00003 respectively). However, there was no difference in ventricular activation time (VAT) between groups. Conclusions CAE ECGs were found to be associated with increased Tp-Te, Tp-Te/QT ratio, QTc intervals and P-wave dispersions. This may suggest that CAE existence has a pro-arrhythmogenic nature.
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Affiliation(s)
- Ronan Conlon
- Letterkenny University Hospital, Letterkenny, Co. Donegal, Ireland
| | - Richard Tanner
- Letterkenny University Hospital, Letterkenny, Co. Donegal, Ireland
| | - Santhosh David
- Letterkenny University Hospital, Letterkenny, Co. Donegal, Ireland
| | - Gabor Szeplaki
- Heart and Vascular Center, Mater Private Hospital, Dublin 2, Ireland
| | - Joseph Galvin
- Heart and Vascular Center, Mater Private Hospital, Dublin 2, Ireland
| | - John Keaney
- Heart and Vascular Center, Mater Private Hospital, Dublin 2, Ireland
| | - Edward Keelan
- Heart and Vascular Center, Mater Private Hospital, Dublin 2, Ireland
| | - Usama Boles
- Letterkenny University Hospital, Letterkenny, Co. Donegal, Ireland.,Heart and Vascular Center, Mater Private Hospital, Dublin 2, Ireland
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Ortega FA, Grandi E, Krogh-Madsen T, Christini DJ. Applications of Dynamic Clamp to Cardiac Arrhythmia Research: Role in Drug Target Discovery and Safety Pharmacology Testing. Front Physiol 2018; 8:1099. [PMID: 29354069 PMCID: PMC5758594 DOI: 10.3389/fphys.2017.01099] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 12/13/2017] [Indexed: 12/31/2022] Open
Abstract
Dynamic clamp, a hybrid-computational-experimental technique that has been used to elucidate ionic mechanisms underlying cardiac electrophysiology, is emerging as a promising tool in the discovery of potential anti-arrhythmic targets and in pharmacological safety testing. Through the injection of computationally simulated conductances into isolated cardiomyocytes in a real-time continuous loop, dynamic clamp has greatly expanded the capabilities of patch clamp outside traditional static voltage and current protocols. Recent applications include fine manipulation of injected artificial conductances to identify promising drug targets in the prevention of arrhythmia and the direct testing of model-based hypotheses. Furthermore, dynamic clamp has been used to enhance existing experimental models by addressing their intrinsic limitations, which increased predictive power in identifying pro-arrhythmic pharmacological compounds. Here, we review the recent advances of the dynamic clamp technique in cardiac electrophysiology with a focus on its future role in the development of safety testing and discovery of anti-arrhythmic drugs.
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Affiliation(s)
- Francis A Ortega
- Physiology, Biophysics, and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, United States
| | - Eleonora Grandi
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Trine Krogh-Madsen
- Greenberg Division of Cardiology, Weill Cornell Medical College, New York, NY, United States
| | - David J Christini
- Physiology, Biophysics, and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, United States.,Greenberg Division of Cardiology, Weill Cornell Medical College, New York, NY, United States
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Annecchino LA, Schultz SR. Progress in automating patch clamp cellular physiology. Brain Neurosci Adv 2018; 2:2398212818776561. [PMID: 32166142 PMCID: PMC7058203 DOI: 10.1177/2398212818776561] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 04/19/2018] [Indexed: 12/30/2022] Open
Abstract
Patch clamp electrophysiology has transformed research in the life sciences over the last few decades. Since their inception, automatic patch clamp platforms have evolved considerably, demonstrating the capability to address both voltage- and ligand-gated channels, and showing the potential to play a pivotal role in drug discovery and biomedical research. Unfortunately, the cell suspension assays to which early systems were limited cannot recreate biologically relevant cellular environments, or capture higher order aspects of synaptic physiology and network dynamics. In vivo patch clamp electrophysiology has the potential to yield more biologically complex information and be especially useful in reverse engineering the molecular and cellular mechanisms of single-cell and network neuronal computation, while capturing important aspects of human disease mechanisms and possible therapeutic strategies. Unfortunately, it is a difficult procedure with a steep learning curve, which has restricted dissemination of the technique. Luckily, in vivo patch clamp electrophysiology seems particularly amenable to robotic automation. In this review, we document the development of automated patch clamp technology, from early systems based on multi-well plates through to automated planar-array platforms, and modern robotic platforms capable of performing two-photon targeted whole-cell electrophysiological recordings in vivo.
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Affiliation(s)
- Luca A. Annecchino
- Centre for Neurotechnology and Department of Bioengineering, Imperial College London, London, UK
| | - Simon R. Schultz
- Centre for Neurotechnology and Department of Bioengineering, Imperial College London, London, UK
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Looking at late repolarization to see early disease. Rev Port Cardiol 2017; 36:925-926. [PMID: 29233644 DOI: 10.1016/j.repc.2017.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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49
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Evaluation of QT dispersion and T-peak to T-end interval in patients with early-stage sarcoidosis. REVISTA PORTUGUESA DE CARDIOLOGIA (ENGLISH EDITION) 2017. [DOI: 10.1016/j.repce.2017.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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50
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Looking at late repolarization to see early disease. REVISTA PORTUGUESA DE CARDIOLOGIA (ENGLISH EDITION) 2017. [DOI: 10.1016/j.repce.2017.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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