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Scacchi S, Pavarino LF, Mazzanti A, Trancuccio A, Priori SG, Colli Franzone P. Transmural APD heterogeneity determines ventricular arrhythmogenesis in LQT8 syndrome: Insights from Bidomain computational modeling. PLoS One 2024; 19:e0305248. [PMID: 38968219 DOI: 10.1371/journal.pone.0305248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/27/2024] [Indexed: 07/07/2024] Open
Abstract
Long QT Syndrome type 8 (LQT8) is a cardiac arrhythmic disorder associated with Timothy Syndrome, stemming from mutations in the CACNA1C gene, particularly the G406R mutation. While prior studies hint at CACNA1C mutations' role in ventricular arrhythmia genesis, the mechanisms, especially in G406R presence, are not fully understood. This computational study explores how the G406R mutation, causing increased transmural dispersion of repolarization, induces and sustains reentrant ventricular arrhythmias. Using three-dimensional numerical simulations on an idealized left-ventricular model, integrating the Bidomain equations with the ten Tusscher-Panfilov ionic model, we observe that G406R mutation with 11% and 50% heterozygosis significantly increases transmural dispersion of repolarization. During S1-S4 stimulation protocols, these gradients facilitate conduction blocks, triggering reentrant ventricular tachycardia. Sustained reentry pathways occur only with G406R mutation at 50% heterozygosis, while neglecting transmural heterogeneities of action potential duration prevents stable reentry, regardless of G406R mutation presence.
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Affiliation(s)
- Simone Scacchi
- Dipartimento di Matematica, Università degli Studi di Milano, Milano, Italy
| | - Luca F Pavarino
- Dipartimento di Matematica, Università degli Studi di Pavia, Pavia, Italy
| | - Andrea Mazzanti
- Molecular Cardiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Alessandro Trancuccio
- Molecular Cardiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Silvia G Priori
- Molecular Cardiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
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Pökel C, Schulze A, Busse M. Cardiovascular and Vector-Cardiographic Effects of Articaine Anesthesia with Epinephrine. Int J Dent 2024; 2024:8610423. [PMID: 38962723 PMCID: PMC11221961 DOI: 10.1155/2024/8610423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/22/2024] [Accepted: 05/21/2024] [Indexed: 07/05/2024] Open
Abstract
The aim was to investigate the vector-cardiographic effects in patients submitted to dental extraction under local anesthesia. Twenty-one patients aged 36.6 ± 12.4 years with a clinical and radiographic indication of mandibular or maxillary tooth extraction were enrolled. The intervention was a local or mandibular nerve block anesthesia with 4% articaine hydrochloride containing epinephrine (1 : 100,000; 40 mg/ml + 10 μg/ml). Blood pressure (BP), heart rate (HR), pulse wave transit time, and vector-cardiography data were recorded throughout 3 min before and 5 min after injection. QRS- and T-wave area under the curve (QRS AUC/T AUC) were calculated from the X/Y/Z QRS-vector or T-vector. T-wave amplitude (T AM), T AUC values, and diastolic BP decreased, and HR significantly increased 4 min after injection. A transient moderate HR drop and a corresponding small increase in T AM and T AUC immediately after the injection procedure may be explained by a decreased sympathetic tone due to psychological relief. In dental anesthesia, the systemic epinephrine effects are represented by a decrease in T AUC. These effects are most pronounced in the X- and Y-leads. The 3D determination of vector planes or amplitudes is a simple method to register the sympathetic tone in local anesthesia independently of possible effects on T-wave characteristics in single leads. In conclusion, T-wave determination may help to detect even small increases in systemic adrenaline concentration in case of accidental intravascular injection. At the same time, full rhythm and spatial ischemia control is provided.
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Affiliation(s)
- Christoph Pökel
- General Outpatient Clinic of Sports MedicineUniversity Leipzig, Leipzig, Germany
| | - Antina Schulze
- Department of Sports DentistryInstitute of Sports MedicineUniversity Leipzig, Leipzig, Germany
| | - Martin Busse
- General Outpatient Clinic of Sports MedicineUniversity Leipzig, Leipzig, Germany
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Hu W, Zhang W, Zhang K, Al-Moubarak E, Zhang Y, Harmer SC, Hancox JC, Zhang H. Evaluating pro-arrhythmogenic effects of the T634S-hERG mutation: insights from a simulation study. Interface Focus 2023; 13:20230035. [PMID: 38106919 PMCID: PMC10722218 DOI: 10.1098/rsfs.2023.0035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 11/06/2023] [Indexed: 12/19/2023] Open
Abstract
A mutation to serine of a conserved threonine (T634S) in the hERG K+ channel S6 pore region has been identified as a variant of uncertain significance, showing a loss-of-function effect. However, its potential consequences for ventricular excitation and arrhythmogenesis have not been reported. This study evaluated possible functional effects of the T634S-hERG mutation on ventricular excitation and arrhythmogenesis by using multi-scale computer models of the human ventricle. A Markov chain model of the rapid delayed rectifier potassium current (IKr) was reconstructed for wild-type and T634S-hERG mutant conditions and incorporated into the ten Tusscher et al. models of human ventricles at cell and tissue (1D, 2D and 3D) levels. Possible functional impacts of the T634S-hERG mutation were evaluated by its effects on action potential durations (APDs) and their rate-dependence (APDr) at the cell level; and on the QT interval of pseudo-ECGs, tissue vulnerability to unidirectional conduction block (VW), spiral wave dynamics and repolarization dispersion at the tissue level. It was found that the T634S-hERG mutation prolonged cellular APDs, steepened APDr, prolonged the QT interval, increased VW, destablized re-entry and augmented repolarization dispersion across the ventricle. Collectively, these results imply potential pro-arrhythmic effects of the T634S-hERG mutation, consistent with LQT2.
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Affiliation(s)
- Wei Hu
- Biological Physics Group, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - Wenfeng Zhang
- College of Computer and Information Science, Chongqing Normal University, Chongqing, People's Republic of China
| | - Kevin Zhang
- Southmead Hospital, North Bristol Trust, Bristol, UK
| | - Ehab Al-Moubarak
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Yihong Zhang
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Stephen C. Harmer
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Jules C. Hancox
- Biological Physics Group, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Henggui Zhang
- Biological Physics Group, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou 646000, People's Republic of China
- Beijing Academy of Artificial Intelligence, Beijing 100084, People's Republic of China
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İnci Ü, Güzel T. The effect of empagliflozin on index of cardio-electrophysiological balance in patients with diabetes mellitus. Pacing Clin Electrophysiol 2023; 46:44-49. [PMID: 36370429 DOI: 10.1111/pace.14621] [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: 07/30/2022] [Revised: 09/16/2022] [Accepted: 11/05/2022] [Indexed: 11/13/2022]
Abstract
BACKGROUND Empagliflozin is a new antidiabetic drug with positive effects on glucose regulation and the prevention of cardiovascular diseases (CVD). The effect of empagliflozin on arrhythmias has not been adequately studied. The index of cardio-electrophysiological balance (iCEB) is a popular marker used to predict ventricular arrhythmias. Therefore, in our study, we aimed to examine the effect of empagliflozin on iCEB and iCEBc in patients with type 2 diabetes mellitus (T2DM) without heart failure (HF). METHODS A total of 70 patients were included in the study prospectively. Electrocardiographic and echocardiographic evaluations of all patients were reviewed at baseline and the end of the third month. RESULTS The median age of the patients was 57 (43-68 IQR), and 30 (42.9%) were male. Tp-e (100 [88-120] vs. 94 [82-105], p = .01), Tp-e/QT (0.27 [0.25-0.33] vs. 0.25 [0.23-0.30], p = .001) were significantly shorter after treatment. iCEB (4.24 [3.8-4.5] vs. 3.92 [3.79-4.42], p = .009) and iCEBc (4.78 [4.25-4.92] vs. 4.48 [4.0-4.71], p = .001) values decreased significantly after treatment compared to baseline. CONCLUSIONS Tp-e, Tp-e/QT, iCEB, and iCEBc values decreased within physiological limits in patients with T2DM without HF. This result may be associated with a reduced risk of potential ventricular arrhythmias.
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Affiliation(s)
- Ümit İnci
- Department of Cardiology, Health Science University, Gazi Yasargil Training and Research Hospital, Diyarbakir, Turkey
| | - Tuncay Güzel
- Department of Cardiology, Health Science University, Gazi Yasargil Training and Research Hospital, Diyarbakir, Turkey
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Rieder M, Kreifels P, Stuplich J, Ziupa D, Servatius H, Nicolai L, Castiglione A, Zweier C, Asatryan B, Odening KE. Genotype-Specific ECG-Based Risk Stratification Approaches in Patients With Long-QT Syndrome. Front Cardiovasc Med 2022; 9:916036. [PMID: 35911527 PMCID: PMC9329832 DOI: 10.3389/fcvm.2022.916036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Background Congenital long-QT syndrome (LQTS) is a major cause of sudden cardiac death (SCD) in young individuals, calling for sophisticated risk assessment. Risk stratification, however, is challenging as the individual arrhythmic risk varies pronouncedly, even in individuals carrying the same variant. Materials and Methods In this study, we aimed to assess the association of different electrical parameters with the genotype and the symptoms in patients with LQTS. In addition to the heart-rate corrected QT interval (QTc), markers for regional electrical heterogeneity, such as QT dispersion (QTmax-QTmin in all ECG leads) and delta Tpeak/end (Tpeak/end V5 – Tpeak/end V2), were assessed in the 12-lead ECG at rest and during exercise testing. Results QTc at rest was significantly longer in symptomatic than asymptomatic patients with LQT2 (493.4 ms ± 46.5 ms vs. 419.5 ms ± 28.6 ms, p = 0.004), but surprisingly not associated with symptoms in LQT1. In contrast, post-exercise QTc (minute 4 of recovery) was significantly longer in symptomatic than asymptomatic patients with LQT1 (486.5 ms ± 7.0 ms vs. 463.3 ms ± 16.3 ms, p = 0.04), while no such difference was observed in patients with LQT2. Enhanced delta Tpeak/end and QT dispersion were only associated with symptoms in LQT1 (delta Tpeak/end 19.0 ms ± 18.1 ms vs. −4.0 ms ± 4.4 ms, p = 0.02; QT-dispersion: 54.3 ms ± 10.2 ms vs. 31.4 ms ± 10.4 ms, p = 0.01), but not in LQT2. Delta Tpeak/end was particularly discriminative after exercise, where all symptomatic patients with LQT1 had positive and all asymptomatic LQT1 patients had negative values (11.8 ± 7.9 ms vs. −7.5 ± 1.7 ms, p = 0.003). Conclusion Different electrical parameters can distinguish between symptomatic and asymptomatic patients in different genetic forms of LQTS. While the classical “QTc at rest” was only associated with symptoms in LQT2, post-exercise QTc helped distinguish between symptomatic and asymptomatic patients with LQT1. Enhanced regional electrical heterogeneity was only associated with symptoms in LQT1, but not in LQT2. Our findings indicate that genotype-specific risk stratification approaches based on electrical parameters could help to optimize risk assessment in LQTS.
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Affiliation(s)
- Marina Rieder
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Paul Kreifels
- Department of Cardiology and Angiology I, Faculty of Medicine, University Heart Center Freiburg-Bad Krozingen, University of Freiburg, Freiburg, Germany
| | - Judith Stuplich
- Department of Cardiology and Angiology I, Faculty of Medicine, University Heart Center Freiburg-Bad Krozingen, University of Freiburg, Freiburg, Germany
| | - David Ziupa
- Department of Cardiology and Angiology I, Faculty of Medicine, University Heart Center Freiburg-Bad Krozingen, University of Freiburg, Freiburg, Germany
| | - Helge Servatius
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Luisa Nicolai
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Alessandro Castiglione
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Christiane Zweier
- Department of Human Genetics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Babken Asatryan
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Katja E Odening
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
- Department of Physiology, University of Bern, Bern, Switzerland
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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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Safe electrophysiologic profile of dexmedetomidine in different experimental arrhythmia models. Sci Rep 2021; 11:23940. [PMID: 34907251 PMCID: PMC8671395 DOI: 10.1038/s41598-021-03364-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 11/23/2021] [Indexed: 12/14/2022] Open
Abstract
Previous studies suggest an impact of dexmedetomidine on cardiac electrophysiology. However, experimental data is sparse. Therefore, purpose of this study was to investigate the influence of dexmedetomidine on different experimental models of proarrhythmia. 50 rabbit hearts were explanted and retrogradely perfused. The first group (n = 12) was treated with dexmedetomidine in ascending concentrations (3, 5 and 10 µM). Dexmedetomidine did not substantially alter action potential duration (APD) but reduced spatial dispersion of repolarization (SDR) and rendered the action potentials rectangular, resulting in no proarrhythmia. In further 12 hearts, erythromycin (300 µM) was administered to simulate long-QT-syndrome-2 (LQT2). Additional treatment with dexmedetomidine reduced SDR, thereby suppressing torsade de pointes. In the third group (n = 14), 0.5 µM veratridine was added to reduce the repolarization reserve. Further administration of dexmedetomidine did not influence APD, SDR or the occurrence of arrhythmias. In the last group (n = 12), a combination of acetylcholine (1 µM) and isoproterenol (1 µM) was used to facilitate atrial fibrillation. Additional treatment with dexmedetomidine prolonged the atrial APD but did not reduce AF episodes. In this study, dexmedetomidine did not significantly alter cardiac repolarization duration and was not proarrhythmic in different models of ventricular and atrial arrhythmias. Of note, dexmedetomidine might be antiarrhythmic in acquired LQT2 by reducing SDR.
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Ellermann C, Wolfes J, Eckardt L, Frommeyer G. Role of the rabbit whole-heart model for electrophysiologic safety pharmacology of non-cardiovascular drugs. Europace 2021; 23:828-836. [PMID: 33200170 DOI: 10.1093/europace/euaa288] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 08/27/2020] [Indexed: 11/13/2022] Open
Abstract
Plenty of non-cardiovascular drugs alter cardiac electrophysiology and may ultimately lead to life-threatening arrhythmias. In clinical practice, measuring the QT interval as a marker for the repolarization period is the most common tool to assess the electrophysiologic safety of drugs. However, the sole measurement of the QT interval may be insufficient to determine the proarrhythmic risk of non-cardiovascular agents. Several other markers are considered in pre-clinical safety testing to determine potential harm on cardiac electrophysiology. Besides measuring typical electrophysiologic parameters such as repolarization duration, whole-heart models allow the determination of potential predictors for proarrhythmia. Spatial and temporal heterogeneity as well as changes of shape of the action potential can be easily assessed. In addition, provocation manoeuvers (either by electrolyte imbalances or programmed pacing protocols) may induce sustained arrhythmias and thereby determine ventricular vulnerability to arrhythmias. Compared with the human heart, the rabbit heart possesses a similar distribution of ion currents that govern cardiac repolarization, resulting in a rectangular action potential configuration in both species. In addition, similar biophysical properties of rabbit and human cardiac ion channels lead to a comparable pharmacologic response in human and rabbit hearts. Of note, arrhythmia patterns resemble in both species due to the similar effective size of human and rabbit hearts. Thus, the rabbit heart is particularly suitable for testing the electrophysiologic safety of drugs. Several experimental setups have been developed for studying cardiac electrophysiology in rabbits, ranging from single cell to tissue preparations, whole-heart setups, and in vivo models.
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Affiliation(s)
- Christian Ellermann
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, Münster D-48149, Germany
| | - Julian Wolfes
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, Münster D-48149, Germany
| | - Lars Eckardt
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, Münster D-48149, Germany
| | - Gerrit Frommeyer
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, Münster D-48149, Germany
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Mora MT, Gong JQX, Sobie EA, Trenor B. The role of β-adrenergic system remodeling in human heart failure: A mechanistic investigation. J Mol Cell Cardiol 2020; 153:14-25. [PMID: 33326834 DOI: 10.1016/j.yjmcc.2020.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 01/01/2023]
Abstract
β-adrenergic receptor antagonists (β-blockers) are extensively used to improve cardiac performance in heart failure (HF), but the electrical improvements with these clinical treatments are not fully understood. The aim of this study was to analyze the electrophysiological effects of β-adrenergic system remodeling in heart failure with reduced ejection fraction and the underlying mechanisms. We used a combined mathematical model that integrated β-adrenergic signaling with electrophysiology and calcium cycling in human ventricular myocytes. HF remodeling, both in the electrophysiological and signaling systems, was introduced to quantitatively analyze changes in electrophysiological properties due to the stimulation of β-adrenergic receptors in failing myocytes. We found that the inotropic effect of β-adrenergic stimulation was reduced in HF due to the altered Ca2+ dynamics resulting from the combination of structural, electrophysiological and signaling remodeling. Isolated cells showed proarrhythmic risk after sympathetic stimulation because early afterdepolarizations appeared, and the vulnerability was greater in failing myocytes. When analyzing coupled cells, β-adrenergic stimulation reduced transmural repolarization gradients between endocardium and epicardium in normal tissue, but was less effective at reducing these gradients after HF remodeling. The comparison of the selective activation of β-adrenergic isoforms revealed that the response to β2-adrenergic receptors stimulation was blunted in HF while β1-adrenergic receptors downstream effectors regulated most of the changes observed after sympathetic stimulation. In conclusion, this study was able to reproduce an altered β-adrenergic activity on failing myocytes and to explain the mechanisms involved. The derived predictions could help in the treatment of HF and guide in the design of future experiments.
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Affiliation(s)
- Maria T Mora
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Jingqi Q X Gong
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Eric A Sobie
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Beatriz Trenor
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain.
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Priya PK, Jayaraman S. Effect of Percentage Reduction in Action Potential Duration of M-cells on Re-entry in Short QT Syndrome. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:2585-2588. [PMID: 33018535 DOI: 10.1109/embc44109.2020.9175751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Increase in transmural dispersion of repolarisation along with a diminished QT interval have been known to aid in the development of arrhythmia during KCNQ1-linked short QT syndrome type 2 (SQTS2). However, the percentage by which action potential duration (APD) shortens in the different cell types that make up the ventricular wall are not fully understood. In this study, the percentage of APD shortening of M-cells was varied to determine the conditions under which re-entry occurs during SQTS2. A 2D transmural section of the heart with anisotropic properties is considered. Slight modifications to the TP06 equations are used to simulate the electrophysiology of the endocardial (endo), midmyocardial (M) and epicardial (epi) cells. A discrete network of 250×100 cells are interconnected using gap junction conductances and from this, a pseudo ECG is generated. On pacing the tissue with premature beats in the midst of normal pacing pulses and on including SQTS, it is observed that re-entry is sustained for a longer duration when the APD shortening in M-cells is more compared to the epi or endo cells while the percentage reduction in APD of M-cells is about 5% to 7% lesser than that in epi and endo cells. Further, when the percentage reduction in APD of M-cells is similar to epi or endo cells, no re-entry is generated. This analysis highlights the key role of percentage reduction in APD of M-cells compared to epi and endo cells in maintaining the re-entrant waves.
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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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Abstract
OBJECTIVE The aim of this study was to evaluate the influence of sex on left ventricular mechanics in hypertensive individuals. METHODS This cross-sectional study included 171 untreated hypertensive patients and 112 normotensive controls who underwent a 24-h ambulatory blood pressure monitoring and comprehensive echocardiographic examination including strain assessment. RESULTS Hypertensive women and men had significantly lower left ventricular global longitudinal and circumferential strains than their normotensive counterparts. Left ventricular global longitudinal strain was lower in hypertensive men than in women (-19.8 ± 2.2 vs. -17.9 ± 2.1%; P < 0.01). Left ventricular global circumferential strain was also reduced in hypertensive men in comparison with women (-21.0 ± 2.5 vs. -18.7 ± 2.3%; P < 0.01). The difference in left ventricular radial strain was not discovered between hypertensive women and men. Furthermore, left ventricular twist was significantly higher in hypertensive women than in hypertensive men (21.9 ± 4.1° vs. 20.6 ± 3.8°; P = 0.034). Female sex and arterial hypertension, and also their interaction, were associated with lower left ventricular mass index, increased left ventricular global longitudinal, and circumferential strains and increased left ventricular twist compared with hypertensive men. CONCLUSION Left ventricular longitudinal and circumferential strains were significantly reduced in hypertensive patients. However, the changes are more pronounced in hypertensive men than in women. Sex has a significant effect on the association between hypertension, and longitudinal and circumferential strain.
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Emet S, Onur ST, Sokucu SN, Aydin S, Dalar L, Cetinkaya E, Onur I. A new electrocardiographic parameter associated with sudden cardiac death in pulmonary sarcoidosis. Arch Med Sci 2020; 16:559-568. [PMID: 32399103 PMCID: PMC7212222 DOI: 10.5114/aoms.2019.88393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Accepted: 05/21/2019] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION The interval from the peak to the end of the electrocardiographic T wave (Tp-Te) may correspond to malignant ventricular arrhythmias. In this study we aimed to assess Tp-Te variability and investigate the transmural dispersion of repolarisation in pulmonary sarcoidosis disease without proofed cardiac involvement. MATERIAL AND METHODS This was a retrospective case-control study that included patients who had a pathologic and radiologic diagnosis of sarcoidosis. All data of the patients' demographic features and electrocardiographs were analysed. RESULTS We enrolled 78 patients with sarcoidosis and 54 healthy volunteers as controls in our study. Men comprised 36% of the sarcoidosis group and 27% of controls. The mean age in the sarcoidosis and control group was 45.4 ±8.7 years (range: 23-58 years) and 44.6 ±11.9 years (range: 21-73 years), respectively. There was no significant difference between the groups for age or sex (p = 0.654, p = 0.246, respectively). There was a significant increase in Tp-Te results in all precordial leads in the sarcoidosis group compared with the control group (p < 0.05). CONCLUSIONS Pulmonary sarcoidosis is suspected to have cardiac involvement; therefore, we need to develop new approaches. We present strong evidence that Tp-Te intervals were increased in patients with pulmonary sarcoidosis, which suggests that there may be a link between sarcoidosis and ventricular arrhythmias without proofed cardiac involvement.
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Affiliation(s)
- Samim Emet
- Department of Cardiology, Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Seda T. Onur
- Yedikule Chest Disease Training and Research Hospital, Istanbul, Turkey
| | - Sinem N. Sokucu
- Yedikule Chest Disease Training and Research Hospital, Istanbul, Turkey
| | - Senay Aydin
- Yedikule Chest Disease Training and Research Hospital, Istanbul, Turkey
| | - Levent Dalar
- Yedikule Chest Disease Training and Research Hospital, Istanbul, Turkey
| | - Erdogan Cetinkaya
- Yedikule Chest Disease Training and Research Hospital, Istanbul, Turkey
| | - Imran Onur
- Department of Cardiology, Faculty of Medicine, Istanbul University, Istanbul, Turkey
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14
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Yamin M, Yuniadi Y, Alwi I, Setiati S, Munawar M. Endocardial biventricular pacing for chronic heart failure patients: Effect on transmural dispersion of repolarization. J Arrhythm 2019; 35:664-669. [PMID: 31410237 PMCID: PMC6686357 DOI: 10.1002/joa3.12205] [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: 11/22/2018] [Revised: 04/15/2019] [Accepted: 05/08/2019] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND AND AIM Conventional epicardial cardiac resynchronization therapy (CRT) can cause fatal arrhythmia associated with increased transmural dispersion of repolarization (TDR). It is unknown whether endocardial biventricular pacing in various locations will decrease TDR and hence the occurrence of fatal arrhythmia. This study aimed to find out the most effective location of endocardial biventricular pacing resulting in the shortest homogenous TDR. METHODS A before-and-after study on adult chronic heart failure (CHF) patients undergoing endocardial biventricular pacing in several defined locations. The changes in TDR from baseline were compared among various pacing locations. RESULTS Fourteen subjects were included with age ranged 36-74 years old, of which 10 were males. Location revealed the highest post biventricular pacing TDR (113.4 (SD 13.8) ms) was the outlet septum of right ventricle in combination with lateral wall of left ventricle (RVOTseptum-LVlateral) while the lowest one (106.1 (SD 11.6) ms) was of the right ventricular apex and posterolateral left ventricle (RVapex-LVposterolateral). Two CRT locations resulted in the most homogenous TDR, that is the right ventricular apex - left ventricular lateral wall (RVapex-LVlateral, mean difference -9.43; 95% CI (-19.72;0.87) ms, P = 0.07) and right ventricular apex - left ventricle posterolateral wall (RVapex-LVposterolateral, mean difference -6.85; 95% CI (-13.93;0.22) ms, P = 0.056). CONCLUSION Endocardial biventricular pacing on right ventricular apex and left ventricular lateral/posterolateral walls results in the most homogenous TDR.
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Affiliation(s)
- Muhammad Yamin
- Department of Internal Medicine, Faculty of MedicineUniversitas Indonesia – Cipto Mangunkusumo HospitalJakartaIndonesia
| | - Yoga Yuniadi
- Department of CardiologyUniversitas IndonesiaJakartaIndonesia
| | - Idrus Alwi
- Department of Internal Medicine, Faculty of MedicineUniversitas Indonesia – Cipto Mangunkusumo HospitalJakartaIndonesia
| | - Siti Setiati
- Department of Internal Medicine, Faculty of MedicineUniversitas Indonesia – Cipto Mangunkusumo HospitalJakartaIndonesia
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Boduroglu Y, Son O. Assessment of Tp-Te Interval and Tp-Te/Qt Ratio in Patients with Aortic Aneurysm. Open Access Maced J Med Sci 2019; 7:943-948. [PMID: 30976337 PMCID: PMC6454177 DOI: 10.3889/oamjms.2019.191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Arrhythmic disorders in the aortic aneurysm (AA) have been rarely reported. AIM The study aimed to assess the repolarisation indices of ventricular arrhythmia (VA) (mainly Tp-Te interval and Tp-Te/QT ratio) in patients with AA. METHODS A group of 98 patients with AA and 75 patients as control were recruited. Many of indices of ventricular arrhythmia were assessed. RESULTS Many of indices like QT, QTc, QTpc, Tp-Te/QT, Tp-Te/QTc, Tp-Tec/QTc, S-Tp, S-Tpc, S-Te, S-Tec and fQRS were found to be significantly different in AA group (for all P < 0.05). However, QTp, mean Tp-Te and Tp-Tec were not found different (for all P < 0.05). Aortic diameter (Ao-D) was found to have a positive correlation with QTc, QTpc, S-Tp, S-Tpc, S-Te, S-Tec, fQRS (for all P < 0,05) and negative correlation withTp-Te/QT (P = 0.047). The best cut-off level for prediction of Tp-Te ≥100 ms was found the Ao-D > 43.5 mm in ROC analysis (AUC: 0.69; P = 0.151) with sensitivity 60% and specificity 79.6%. CONCLUSIONS Although our study did not find any differences for mean Tp-Te interval between groups, many of other indexes of TDR were found to be significantly different. Ao-D was found to have significant correlations with many indices.
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Affiliation(s)
- Yalcin Boduroglu
- Department of Cardiology, Ahi Evran University Education and Research Hospital, Kirsehir, Turkey
| | - Osman Son
- Department of Endocrinology, Private Acibadem Hospital, Eskisehir, Turkey
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16
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Khokhlova A, Balakina-Vikulova N, Katsnelson L, Iribe G, Solovyova O. Transmural cellular heterogeneity in myocardial electromechanics. J Physiol Sci 2018; 68:387-413. [PMID: 28573594 PMCID: PMC10717105 DOI: 10.1007/s12576-017-0541-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 04/24/2017] [Indexed: 12/22/2022]
Abstract
Myocardial heterogeneity is an attribute of the normal heart. We have developed integrative models of cardiomyocytes from the subendocardial (ENDO) and subepicardial (EPI) ventricular regions that take into account experimental data on specific regional features of intracellular electromechanical coupling in the guinea pig heart. The models adequately simulate experimental data on the differences in the action potential and contraction between the ENDO and EPI cells. The modeling results predict that heterogeneity in the parameters of calcium handling and myofilament mechanics in isolated ENDO and EPI cardiomyocytes are essential to produce the differences in Ca2+ transients and contraction profiles via cooperative mechanisms of mechano-calcium-electric feedback and may further slightly modulate transmural differences in the electrical properties between the cells. Simulation results predict that ENDO cells have greater sensitivity to changes in the mechanical load than EPI cells. These data are important for understanding the behavior of cardiomyocytes in the intact heart.
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Affiliation(s)
- Anastasia Khokhlova
- Ural Federal University, Ekaterinburg, Russia.
- Institute of Immunology and Physiology, Russian Academy of Sciences, 106 Pervomayskaya, Ekaterinburg, 620049, Russia.
| | - Nathalie Balakina-Vikulova
- Ural Federal University, Ekaterinburg, Russia
- Institute of Immunology and Physiology, Russian Academy of Sciences, 106 Pervomayskaya, Ekaterinburg, 620049, Russia
| | - Leonid Katsnelson
- Ural Federal University, Ekaterinburg, Russia
- Institute of Immunology and Physiology, Russian Academy of Sciences, 106 Pervomayskaya, Ekaterinburg, 620049, Russia
| | - Gentaro Iribe
- Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Olga Solovyova
- Ural Federal University, Ekaterinburg, Russia
- Institute of Immunology and Physiology, Russian Academy of Sciences, 106 Pervomayskaya, Ekaterinburg, 620049, Russia
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Teplenin AS, Dierckx H, de Vries AAF, Pijnappels DA, Panfilov AV. Paradoxical Onset of Arrhythmic Waves from Depolarized Areas in Cardiac Tissue Due to Curvature-Dependent Instability. PHYSICAL REVIEW. X 2018; 8:021077. [PMID: 30210937 PMCID: PMC6130777 DOI: 10.1103/physrevx.8.021077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The generation of abnormal excitations in pathological regions of the heart is a main trigger for lethal cardiac arrhythmias. Such abnormal excitations, also called ectopic activity, often arise from areas with local tissue heterogeneity or damage accompanied by localized depolarization. Finding the conditions that lead to ectopy is important to understand the basic biophysical principles underlying arrhythmia initiation and might further refine clinical procedures. In this study, we are the first to address the question of how geometry of the abnormal region affects the onset of ectopy using a combination of experimental, in silico, and theoretical approaches. We paradoxically find that, for any studied geometry of the depolarized region in optogenetically modified monolayers of cardiac cells, primary ectopic excitation originates at areas of maximal curvature of the boundary, where the stimulating electrotonic currents are minimal. It contradicts the standard critical nucleation theory applied to nonlinear waves in reaction-diffusion systems, where a higher stimulus is expected to produce excitation more easily. Our in silico studies reveal that the nonconventional ectopic activity is caused by an oscillatory instability at the boundary of the damaged region, the occurrence of which depends on the curvature of that boundary. The onset of this instability is confirmed using the Schrödinger equation methodology proposed by Rinzel and Keener [SIAM J. Appl. Math. 43, 907 (1983)]. Overall, we show distinctively novel insight into how the geometry of a heterogeneous cardiac region determines ectopic activity, which can be used in the future to predict the conditions that can trigger cardiac arrhythmias.
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Affiliation(s)
- Alexander S. Teplenin
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Leiden, the Netherlands
| | - Hans Dierckx
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Antoine A. F. de Vries
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Leiden, the Netherlands
| | - Daniël A. Pijnappels
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Leiden, the Netherlands
| | - Alexander V. Panfilov
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Leiden, the Netherlands
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
- Ural Federal University, Ekaterinburg, Russia
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18
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Janusek D, Svehlikova J, Zelinka J, Weigl W, Zaczek R, Opolski G, Tysler M, Maniewski R. The roles of mid-myocardial and epicardial cells in T-wave alternans development: a simulation study. Biomed Eng Online 2018; 17:57. [PMID: 29739399 PMCID: PMC5941457 DOI: 10.1186/s12938-018-0492-6] [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: 12/14/2017] [Accepted: 04/28/2018] [Indexed: 01/31/2023] Open
Abstract
Background The occurrence of T-wave alternans in electrocardiographic signals was recently linked to susceptibility to ventricular arrhythmias and sudden cardiac death. Thus, by detecting and comprehending the origins of T-wave alternans, it might be possible to prevent such events. Results Here, we simulated T-wave alternans in a computer-generated human heart model by modulating the action potential duration and amplitude during the first part of the repolarization phase. We hypothesized that changes in the intracardiac alternans patterns of action potential properties would differentially influence T-wave alternans measurements at the body surface. Specifically, changes were simulated globally in the whole left and right ventricles to simulate concordant T-wave alternans, and locally in selected regions to simulate discordant and regional discordant, hereinafter referred to as “regional”, T-wave alternans. Body surface potential maps and 12-lead electrocardiographic signals were then computed. In depth discrimination, the influence of epicardial layers on T-wave alternans development was significantly higher than that of mid-myocardial cells. Meanwhile, spatial discrimination revealed that discordant and regional action potential property changes had a higher influence on T-wave alternans amplitude than concordant changes. Notably, varying T-wave alternans sources yielded distinct body surface potential map patterns for T-wave alternans amplitude, which can be used for location of regions within hearts exhibiting impaired repolarization. The highest ability for T-wave alternans detection was achieved in lead V1. Ultimately, we proposed new parameters Vector Magnitude Alternans and Vector Angle Alternans, with higher ability for T-wave alternans detection when using multi-lead electrocardiographic signals processing than for single leads. Finally, QT alternans was found to be associated with the process of T-wave alternans generation. Conclusions The distributions of the body surface T-wave alternans amplitude have been shown to have unique patterns depending on the type of alternans (concordant, discordant or regional) and the location of the disturbance in the heart. The influence of epicardial cells on T-wave alternans development is significantly higher than that of mid-myocardial cells, among which the sub-endocardial layer exerted the highest influence. QT interval alternans is identified as a phenomenon that correlate with T-wave alternans.
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Affiliation(s)
- D Janusek
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks Trojdena Str., 02-109, Warsaw, Poland.
| | - J Svehlikova
- Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - J Zelinka
- Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - W Weigl
- Department of Surgical Sciences/Anaesthesiology and Intensive Care, Uppsala University, Akademiska Hospital, Uppsala, Sweden
| | - R Zaczek
- Department of Cardiology, Central Clinical Hospital of Medical University of Warsaw, Warsaw, Poland
| | - G Opolski
- Department of Cardiology, Central Clinical Hospital of Medical University of Warsaw, Warsaw, Poland
| | - M Tysler
- Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - R Maniewski
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks Trojdena Str., 02-109, Warsaw, Poland
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19
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Salem JE, Nguyen LS, Hammoudi N, Preud'homme G, Hulot JS, Leban M, Funck-Brentano C, Touraine P, Isnard R, Bachelot A. Complex Association of Sex Hormones on Left Ventricular Systolic Function: Insight into Sexual Dimorphism. J Am Soc Echocardiogr 2017; 31:231-240.e1. [PMID: 29246515 DOI: 10.1016/j.echo.2017.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND Normal values of left ventricular ejection fraction (LVEF) and absolute values of global longitudinal strain (GLS) are lower in men than in women. Data concerning the association of sex hormone levels on these left ventricular systolic function surrogates are scarce. The aim of this study was to determine the association of sex hormones with systolic left ventricular function in healthy subjects and patients with congenital adrenal hyperplasia (CAH) as a model of testosterone dysregulation. METHODS Eighty-four adult patients with CAH (58 women; median age, 27 years; interquartile range, 23-36 years) and 84 healthy subjects matched for sex and age were prospectively included. Circulating concentrations of sex hormones were measured within 48 hours of echocardiography with assessment of LVEF and left ventricular longitudinal, radial, and circumferential strain. RESULTS LVEF and GLS were higher in healthy women than in healthy men (63.9 ± 4.2% vs 60.9 ± 5.1% [P < .05] and 20.0 ± 1.9% vs 17.9 ± 2.4% [P < .001], respectively), while there was no difference in LVEF or GLS between women and men with CAH (63.9 ± 4.5% vs 63.0 ± 4.6% [P = NS] and 19.4 ± 2.2% vs 18.3 ± 1.8% [P = NS], respectively). Bioavailable testosterone levels were higher in women with CAH than in female control subjects (0.08 ng/mL [interquartile range, 0.04-0.14 ng/mL] vs 0.16 ng/mL [interquartile range, 0.04-0.3 ng/mL], P < .001) and lower in men with CAH than in male control subjects (2.3 ng/mL [interquartile range, 1.3-3 ng/mL] vs 2.9 ng/mL [interquartile range, 2.5-3.4 ng/mL], P < .05). In men, LVEF and GLS were negatively correlated with bioavailable testosterone levels (r = -0.3, P ≤ .05, and r = -0.45, P < .01, respectively), while midventricular radial strain was positively correlated with bioavailable testosterone level (r = 0.38, P < .05). The absolute value of circumferential strain was positively correlated with follicle-stimulating hormone (r = 0.65, P < .0001). CONCLUSIONS These data support that the existence of sex dimorphism concerning left ventricular systolic cardiac function is significantly associated with testosterone levels.
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Affiliation(s)
- Joe-Elie Salem
- AP-HP, Pitié-Salpêtrière Hospital, Department of Pharmacology and CIC-1421; INSERM, CIC-1421 and UMR ICAN 1166; Sorbonne Universités, Paris, France; UPMC Univ Paris 06, Faculty of Medicine; Sorbonne Universités, UPMC Univ Paris 06, AP-HP, Pitié-Salpêtrière Hospital, Department of Cardiology, Echocardiography Unit, Paris, France; UMR ICAN 1166, Paris, France.
| | - Lee S Nguyen
- AP-HP, Pitié-Salpêtrière Hospital, Department of Pharmacology and CIC-1421; INSERM, CIC-1421 and UMR ICAN 1166; Sorbonne Universités, Paris, France; UPMC Univ Paris 06, Faculty of Medicine; Sorbonne Universités, UPMC Univ Paris 06, AP-HP, Pitié-Salpêtrière Hospital, Department of Cardiology, Echocardiography Unit, Paris, France; UMR ICAN 1166, Paris, France
| | - Nadjib Hammoudi
- Sorbonne Universités, UPMC Univ Paris 06, AP-HP, Pitié-Salpêtrière Hospital, Department of Cardiology, Echocardiography Unit, Paris, France; UMR ICAN 1166, Paris, France
| | - Gisèle Preud'homme
- Sorbonne Universités, UPMC Univ Paris 06, AP-HP, Pitié-Salpêtrière Hospital, Department of Cardiology, Echocardiography Unit, Paris, France; UMR ICAN 1166, Paris, France
| | - Jean-Sebastien Hulot
- AP-HP, Pitié-Salpêtrière Hospital, Department of Pharmacology and CIC-1421; INSERM, CIC-1421 and UMR ICAN 1166; Sorbonne Universités, Paris, France; UPMC Univ Paris 06, Faculty of Medicine; Sorbonne Universités, UPMC Univ Paris 06, AP-HP, Pitié-Salpêtrière Hospital, Department of Cardiology, Echocardiography Unit, Paris, France; UMR ICAN 1166, Paris, France
| | - Monique Leban
- AP-HP, Pitié-Salpêtrière Hospital, IE3M, Department of Endocrinology and Reproductive Medecine, and Centre de Référence des Maladies Endocriniennes Rares de la Croissance et Centre des Pathologies Gynécologiques Rares, and CIC-1421, Paris, France
| | - Christian Funck-Brentano
- AP-HP, Pitié-Salpêtrière Hospital, Department of Pharmacology and CIC-1421; INSERM, CIC-1421 and UMR ICAN 1166; Sorbonne Universités, Paris, France; UPMC Univ Paris 06, Faculty of Medicine
| | - Philippe Touraine
- AP-HP, Pitié-Salpêtrière Hospital, IE3M, Department of Endocrinology and Reproductive Medecine, and Centre de Référence des Maladies Endocriniennes Rares de la Croissance et Centre des Pathologies Gynécologiques Rares, and CIC-1421, Paris, France
| | - Richard Isnard
- Sorbonne Universités, UPMC Univ Paris 06, AP-HP, Pitié-Salpêtrière Hospital, Department of Cardiology, Echocardiography Unit, Paris, France; UMR ICAN 1166, Paris, France
| | - Anne Bachelot
- Sorbonne Universités, UPMC Univ Paris 06, AP-HP, Pitié-Salpêtrière Hospital, Department of Cardiology, Echocardiography Unit, Paris, France; UMR ICAN 1166, Paris, France
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Wutzler A, De Asmundis C, Matsuda H, Bannehr M, Loehr L, Voelk K, Jungmann J, Huemer M, Attanasio P, Parwani A, Boldt LH, Brugada P, Haverkamp W. Effects of propofol on ventricular repolarization and incidence of malignant arrhythmias in adults. J Electrocardiol 2017; 51:170-174. [PMID: 29174097 DOI: 10.1016/j.jelectrocard.2017.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND Propofol is commonly used for procedural sedation in interventional electrophysiology. However, ventricular arrhythmias under Propofol have been reported. Our aim was to investigate ventricular repolarization and incidence of ventricular arrhythmias under Propofol infusion in adults with cardiac arrhythmias. METHODS QRS, QTcB (Bazett), QTcFri (Fridericia), JTc, measurement of T peak to Tend time (Tp-e) at baseline and under Propofol infusion was performed in 235 patients. Screening for unexpected ventricular arrhythmias was performed in 1165 patients undergoing EP procedures under Propofol. RESULTS A significant prolongation of Tp-e under Propofol infusion (79.7±17.3 vs. 86.4±22.5ms, p<0.001) and of QTcFri (429.3±35.8 vs. 435.5±36.5, p=0.033) was detected. No significant change of the QTcB interval, JTc interval or QRS duration was observed. One case (0.09%) of ventricular fibrillation during rapid ventricular pacing under Propofol occurred. CONCLUSION Although transmural dispersion of ventricular repolarisation is increased under Propofol, incidence of malignant ventricular arrhythmias is low. For evaluation of QT interval under Propofol, Fridericia's correction formula should be used rather than Bazett's formula.
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Affiliation(s)
- Alexander Wutzler
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany; Cardiovascular Centre, St. Josef-Hospital, Ruhr-University, Bochum, Germany.
| | - Carlo De Asmundis
- Heart Rhythm Management Centre, University Hospital, Brussels, Belgium
| | - Hisao Matsuda
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
| | - Marwin Bannehr
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
| | - Lena Loehr
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
| | - Katharina Voelk
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
| | - Johannes Jungmann
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
| | - Martin Huemer
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
| | - Philipp Attanasio
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
| | - Abdul Parwani
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
| | - Leif-Hendrik Boldt
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
| | - Pedro Brugada
- Heart Rhythm Management Centre, University Hospital, Brussels, Belgium
| | - Wilhelm Haverkamp
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Germany
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Colman MA, Perez Alday EA, Holden AV, Benson AP. Trigger vs. Substrate: Multi-Dimensional Modulation of QT-Prolongation Associated Arrhythmic Dynamics by a hERG Channel Activator. Front Physiol 2017; 8:757. [PMID: 29046643 PMCID: PMC5632683 DOI: 10.3389/fphys.2017.00757] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/19/2017] [Indexed: 11/13/2022] Open
Abstract
Background: Prolongation of the QT interval of the electrocardiogram (ECG), underlain by prolongation of the action potential duration (APD) at the cellular level, is linked to increased vulnerability to cardiac arrhythmia. Pharmacological management of arrhythmia associated with QT prolongation is typically achieved through attempting to restore APD to control ranges, reversing the enhanced vulnerability to Ca2+-dependent afterdepolarisations (arrhythmia triggers) and increased transmural dispersion of repolarisation (arrhythmia substrate) associated with APD prolongation. However, such pharmacological modulation has been demonstrated to have limited effectiveness. Understanding the integrative functional impact of pharmacological modulation requires simultaneous investigation of both the trigger and substrate. Methods: We implemented a multi-scale (cell and tissue) in silico approach using a model of the human ventricular action potential, integrated with a model of stochastic 3D spatiotemporal Ca2+ dynamics, and parameter modification to mimic prolonged QT conditions. We used these models to examine the efficacy of the hERG activator MC-II-157c in restoring APD to control ranges, examined its effects on arrhythmia triggers and substrates, and the interaction of these arrhythmia triggers and substrates. Results: QT prolongation conditions promoted the development of spontaneous release events underlying afterdepolarisations during rapid pacing. MC-II-157c applied to prolonged QT conditions shortened the APD, inhibited the development of afterdepolarisations and reduced the probability of afterdepolarisations manifesting as triggered activity in single cells. In tissue, QT prolongation resulted in an increased transmural dispersion of repolarisation, which manifested as an increased vulnerable window for uni-directional conduction block. In some cases, MC-II-157c further increased the vulnerable window through its effects on INa. The combination of stochastic release event modulation and transmural dispersion of repolarisation modulation by MC-II-157c resulted in an integrative behavior wherein the arrhythmia trigger is reduced but the arrhythmia substrate is increased, leading to variable and non-linear overall vulnerability to arrhythmia. Conclusion: The relative balance of reduced trigger and increased substrate underlies a multi-dimensional role of MC-II-157c in modulation of cardiac arrhythmia vulnerability associated with prolonged QT interval.
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Affiliation(s)
- Michael A Colman
- School of Biomedical Sciences and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Erick A Perez Alday
- Division of Cardiovascular Medicine, Oregon Health and Science University, Portland, OR, United States
| | - Arun V Holden
- School of Biomedical Sciences and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Alan P Benson
- School of Biomedical Sciences and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
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22
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Dinshaw L, Münch J, Dickow J, Lezius S, Willems S, Hoffmann BA, Patten M. The T-peak-to-T-end interval: a novel ECG marker for ventricular arrhythmia and appropriate ICD therapy in patients with hypertrophic cardiomyopathy. Clin Res Cardiol 2017; 107:130-137. [PMID: 28965260 DOI: 10.1007/s00392-017-1164-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 09/19/2017] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Hypertrophic cardiomyopathy (HCM) is associated with an increased risk of sudden cardiac death (SCD) primarily due to ventricular arrhythmia (VA). In patients (pts.) with a high risk of SCD, the implantation of an intracardiac cardioverter defibrillator (ICD) is thus indicated. Previous studies suggest that a prolonged interval between the peak and the end of the T wave, T-peak to T-end (TpTe), is associated with an elevated risk of VA and SCD in various clinical settings. The aim of our study was to evaluate the association between TpTe and VA in HCM pts. with a previously implanted ICD. METHODS In 40 HCM pts. (51.4 ± 16.4 years; 62.5% men), TpTe was measured using the baseline digital standard resting 12-lead ECG during sinus rhythm. VA was assessed by device follow-up. RESULTS Within 41.8 ± 35.1 months, 7 (17.5%) pts. had VA leading to appropriate therapy (AT), 7 pts. (17.5%) had non-sustained VA, and 26 pts. (65.0%) had no VA. The maximum TpTe was significantly prolonged in pts. with VA leading to AT compared to pts. without VA (101.3 ± 19.6 vs. 79.9 ± 15.3 ms; p = 0.004). Maximum TpTe was associated with an elevated risk of VA leading to AT (hazard ratio per 10 ms increase 1.63; 95% CI 1.04-2.54; p = 0.031) and pts. with a maximum TpTe ≤ 78 ms were without any VA leading to AT during follow-up. There was no correlation of maximum TpTe to other clinical parameters in our patient cohort. CONCLUSION A prolonged TpTe is associated with VA and AT in HCM. Our findings suggest that TpTe can possibly serve as a marker for ventricular arrhythmogenesis in pts. with HCM and assessment of TpTe might, therefore, optimize SCD risk stratification.
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Affiliation(s)
- Leon Dinshaw
- Department of Cardiology-Electrophysiology, University Heart Center Hamburg, Martinistr. 52, 20246, Hamburg, Germany
| | - Julia Münch
- Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistr. 52, 20246, Hamburg, Germany
| | - Jannis Dickow
- Department of Cardiology-Electrophysiology, University Heart Center Hamburg, Martinistr. 52, 20246, Hamburg, Germany
| | - Susanne Lezius
- Institute of Medical Biometry and Epidemiology, University Hospital Hamburg Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Stephan Willems
- Department of Cardiology-Electrophysiology, University Heart Center Hamburg, Martinistr. 52, 20246, Hamburg, Germany
| | - Boris A Hoffmann
- Department of Cardiology-Electrophysiology, University Heart Center Hamburg, Martinistr. 52, 20246, Hamburg, Germany
| | - Monica Patten
- Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistr. 52, 20246, Hamburg, Germany.
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23
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Kirthi Priya P, Reddy MR. Simulation study of the ionic mechanisms underlying Torsade de Pointes in a 2D cardiac tissue. Comput Biol Med 2017; 89:293-303. [PMID: 28858645 DOI: 10.1016/j.compbiomed.2017.08.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 08/18/2017] [Accepted: 08/19/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND To understand the ionic mechanism behind the genesis of Torsade de Pointes (TdP) occurring with long QT syndrome 2 (LQTS2) in a remodelled transmural tissue. METHODS The TP06 model is used to simulate the electrical activity of cells in a 2D transmural ventricular model. LQTS2 is realised by reducing the potassium current (IKr) to 0.5 in each cell. Each cell of the tissue is remodelled by increasing the conductance of calcium current (GCaL). The above two factors make the cells prone to early after depolarizations (EADs) development. The rise in GCaL that can develop a sustained TdP at normal pacing rate is determined from this study. A look at the calcium dynamics, sodium-calcium exchanger current (INaCa) and slow delayed rectifier potassium current (IKs) distribution maps of the tissue helps us in analysing the mechanism of TdP generation. RESULTS A TdP type pattern at normal pacing rate is generated when GCaL is more than 3.5 times the control parameter. From the M-cell island, an adequate number of cells spontaneously release calcium from their sarcoplasmic reticulum leading to increased intracellular calcium and inward sodium current through the sodium calcium exchanger current (INaCa). These contribute to the development of EADs which create a depolarising wavefront that triggers TdP in the tissue. When GCaL is less than 3.5 times the control value, premature ventricular complexes (PVC) occur interspersed between normal beats. CONCLUSION Normal pacing rates can induce a multi focal TdP when sufficient number of M-cells simultaneously undergo spontaneous calcium release (SCR) events.
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Affiliation(s)
- Ponnuraj Kirthi Priya
- Biomedical Engineering Group, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India.
| | - M Ramasubba Reddy
- Biomedical Engineering Group, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India.
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24
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Kirthi Priya P, Reddy MR. Study of factors affecting the progression and termination of drug induced Torsade de pointes in two dimensional cardiac tissue. J Electrocardiol 2017; 50:332-341. [PMID: 28202194 DOI: 10.1016/j.jelectrocard.2017.01.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Indexed: 12/13/2022]
Abstract
INTRODUCTION To study the conditions leading to the initiation and termination of drug induced Torsade de pointes (TdP) along with QT prolongation. METHODS A 2D anisotropic transmural section of the ventricular myocardium is modeled using the TP06 equations and the cells are interconnected with gap junction conductances (GJC). The tissue is remodeled by reducing the repolarization reserve (by increasing calcium current (ICaL)) of all cells thus making them vulnerable to development of early after depolarizations (EADs). RESULTS Clinical risk conditions like decreased potassium current (IKr), bradycardia, hypokalemia and short-long-short (SLS) triggering sequences are included in the tissue. A pseudo-electrocardiogram is created to realize the intensity of remodeling required in presence of risk factors to initiate TdP. On initiating TdP, the effect of increasing GJC and decreasing ICaL is shown to terminate a non-self-limiting TdP. CONCLUSION Without the inclusion of underlying increase in ICaL along with risk factors, TdP cannot be initiated.
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Affiliation(s)
- Ponnuraj Kirthi Priya
- Biomedical Engineering Group, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India.
| | - M Ramasubba Reddy
- Biomedical Engineering Group, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India.
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25
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Chiamvimonvat N, Chen-Izu Y, Clancy CE, Deschenes I, Dobrev D, Heijman J, Izu L, Qu Z, Ripplinger CM, Vandenberg JI, Weiss JN, Koren G, Banyasz T, Grandi E, Sanguinetti MC, Bers DM, Nerbonne JM. Potassium currents in the heart: functional roles in repolarization, arrhythmia and therapeutics. J Physiol 2017; 595:2229-2252. [PMID: 27808412 DOI: 10.1113/jp272883] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 10/11/2016] [Indexed: 12/19/2022] Open
Abstract
This is the second of the two White Papers from the fourth UC Davis Cardiovascular Symposium Systems Approach to Understanding Cardiac Excitation-Contraction Coupling and Arrhythmias (3-4 March 2016), a biennial event that brings together leading experts in different fields of cardiovascular research. The theme of the 2016 symposium was 'K+ channels and regulation', and the objectives of the conference were severalfold: (1) to identify current knowledge gaps; (2) to understand what may go wrong in the diseased heart and why; (3) to identify possible novel therapeutic targets; and (4) to further the development of systems biology approaches to decipher the molecular mechanisms and treatment of cardiac arrhythmias. The sessions of the Symposium focusing on the functional roles of the cardiac K+ channel in health and disease, as well as K+ channels as therapeutic targets, were contributed by Ye Chen-Izu, Gideon Koren, James Weiss, David Paterson, David Christini, Dobromir Dobrev, Jordi Heijman, Thomas O'Hara, Crystal Ripplinger, Zhilin Qu, Jamie Vandenberg, Colleen Clancy, Isabelle Deschenes, Leighton Izu, Tamas Banyasz, Andras Varro, Heike Wulff, Eleonora Grandi, Michael Sanguinetti, Donald Bers, Jeanne Nerbonne and Nipavan Chiamvimonvat as speakers and panel discussants. This article summarizes state-of-the-art knowledge and controversies on the functional roles of cardiac K+ channels in normal and diseased heart. We endeavour to integrate current knowledge at multiple scales, from the single cell to the whole organ levels, and from both experimental and computational studies.
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Affiliation(s)
- Nipavan Chiamvimonvat
- Department of Internal Medicine, University of California, Davis, Genome and Biomedical Science Facility, Rm 6315, Davis, CA, 95616, USA.,Department of Veterans Affairs, Northern California Health Care System, Mather, CA, 95655, USA
| | - Ye Chen-Izu
- Department of Internal Medicine, University of California, Davis, Genome and Biomedical Science Facility, Rm 6315, Davis, CA, 95616, USA.,Department of Pharmacology, University of California, Davis, Genome and Biomedical Science Facility, Rm 3503, Davis, CA, 95616, USA.,Department of Biomedical Engineering, University of California, Davis, Genome and Biomedical Science Facility, Rm 2303, Davis, CA, 95616, USA
| | - Colleen E Clancy
- Department of Pharmacology, University of California, Davis, Genome and Biomedical Science Facility, Rm 3503, Davis, CA, 95616, USA
| | - Isabelle Deschenes
- Department of Physiology and Biophysics, and Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44109, USA.,Heart and Vascular Research Center, MetroHealth Medical Center, Cleveland, OH, 44109, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Hufelandstrasse 55, 45122, Essen, Germany
| | - Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Leighton Izu
- Department of Pharmacology, University of California, Davis, Genome and Biomedical Science Facility, Rm 3503, Davis, CA, 95616, USA
| | - Zhilin Qu
- Division of Cardiology, Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, 3645 MRL, Los Angeles, CA, 90095, USA
| | - Crystal M Ripplinger
- Department of Pharmacology, University of California, Davis, Genome and Biomedical Science Facility, Rm 3503, Davis, CA, 95616, USA
| | - Jamie I Vandenberg
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia
| | - James N Weiss
- Division of Cardiology, Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, 3645 MRL, Los Angeles, CA, 90095, USA
| | - Gideon Koren
- Cardiovascular Research Center, Rhode Island Hospital and the Cardiovascular Institute, The Warren Alpert Medical School of Brown University, Providence, RI, 02903, USA
| | - Tamas Banyasz
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Eleonora Grandi
- Department of Pharmacology, University of California, Davis, Genome and Biomedical Science Facility, Rm 3503, Davis, CA, 95616, USA
| | - Michael C Sanguinetti
- Department of Internal Medicine, University of Utah, Nora Eccles Harrison Cardiovascular Research & Training Institute, Salt Lake City, UT, 84112, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, Genome and Biomedical Science Facility, Rm 3503, Davis, CA, 95616, USA
| | - Jeanne M Nerbonne
- Departments of Developmental Biology and Internal Medicine, Cardiovascular Division, Washington University Medical School, St Louis, MO, 63110, USA
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Abbasi M, Small BG, Patel N, Jamei M, Polak S. Early assessment of proarrhythmic risk of drugs using the in vitro data and single-cell-based in silico models: proof of concept. Toxicol Mech Methods 2016; 27:88-99. [PMID: 27813448 DOI: 10.1080/15376516.2016.1256460] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND PURPOSE To determine the predictive performance of in silico models using drug-specific preclinical cardiac electrophysiology data to investigate drug-induced arrhythmia risk (e.g. Torsade de pointes (TdP)) in virtual human subjects. EXPERIMENTAL APPROACH To assess drug proarrhythmic risk, we used a set of in vitro electrophysiological measurements describing ion channel inhibition triggered by the investigated drugs. The Cardiac Safety Simulator version 2.0 (CSS; Simcyp, Sheffield, UK) platform was used to simulate human left ventricular cardiac myocyte action potential models. RESULTS This study shows the impact of drug concentration changes on particular ionic currents by using available experimental data. The simulation results display safety threshold according to drug concentration threshold and log (threshold concentration/ effective therapeutic plasma concentration (ETPC)). CONCLUSION AND IMPLICATIONS We reproduced the underlying biophysical characteristics of cardiac cells resulted in effects of drugs associated with cardiac arrhythmias (action potential duration (APD) and QT prolongation and TdP) which were observed in published 3D simulations, yet with much less computational burden.
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Affiliation(s)
- Mitra Abbasi
- a Simcyp Limited (a Certara Company), Blades Enterprise Centre , Sheffield , UK
| | - Ben G Small
- a Simcyp Limited (a Certara Company), Blades Enterprise Centre , Sheffield , UK
| | - Nikunjkumar Patel
- a Simcyp Limited (a Certara Company), Blades Enterprise Centre , Sheffield , UK
| | - Masoud Jamei
- a Simcyp Limited (a Certara Company), Blades Enterprise Centre , Sheffield , UK
| | - Sebastian Polak
- a Simcyp Limited (a Certara Company), Blades Enterprise Centre , Sheffield , UK.,b Faculty of Pharmacy , Jagiellonian University Medical College , Krakow , Poland
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27
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Yu CC, Corr C, Shen C, Shelton R, Yadava M, Rhea IB, Straka S, Fishbein MC, Chen Z, Lin SF, Lopshire JC, Chen PS. Small conductance calcium-activated potassium current is important in transmural repolarization of failing human ventricles. Circ Arrhythm Electrophysiol 2015; 8:667-76. [PMID: 25908692 DOI: 10.1161/circep.114.002296] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 04/13/2015] [Indexed: 12/23/2022]
Abstract
BACKGROUND The transmural distribution of apamin-sensitive small conductance Ca(2+)-activated K(+) (SK) current (IKAS) in failing human ventricles remains unclear. METHODS AND RESULTS We optically mapped left ventricular wedge preparations from 12 failing native hearts and 2 rejected cardiac allografts explanted during transplant surgery. We determined transmural action potential duration (APD) before and after 100 nmol/L apamin administration in all wedges and after sequential administration of apamin, chromanol, and E4031 in 4 wedges. Apamin prolonged APD from 363 ms (95% confidence interval [CI], 341-385) to 409 (95% CI, 385-434; P<0.001) in all hearts, and reduced the transmural conduction velocity from 36 cm/s (95% CI, 30-42) to 32 cm/s (95% CI, 27-37; P=0.001) in 12 native failing hearts at 1000 ms pacing cycle length (PCL). The percent APD prolongation is negatively correlated with baseline APD and positively correlated with PCL. Only 1 wedge had M-cell islands. The percentages of APD prolongation in the last 4 hearts at 2000 ms PCL after apamin, chromanol, and E4031 were 9.1% (95% CI, 3.9-14.2), 17.3% (95% CI, 3.1-31.5), and 35.9% (95% CI, 15.7-56.1), respectively. Immunohistochemical staining of subtype 2 of SK protein showed increased expression in intercalated discs of myocytes. CONCLUSIONS SK current is important in the transmural repolarization in failing human ventricles. The magnitude of IKAS is positively correlated with the PCL, but negatively correlated with APD when PCL is fixed. There is abundant subtype 2 of SK protein in the intercalated discs of myocytes.
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Affiliation(s)
- Chih-Chieh Yu
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Christopher Corr
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Changyu Shen
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Richard Shelton
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Mrinal Yadava
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Isaac B Rhea
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Susan Straka
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Michael C Fishbein
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Zhenhui Chen
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Shien-Fong Lin
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - John C Lopshire
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.)
| | - Peng-Sheng Chen
- From the Department of Medicine, Division of Cardiology, Krannert Institute of Cardiology (C.-C.Y., C.C., R.S., M.Y., I.B.R., S.S., Z.C., S.-F.L., J.C.L., P.-S.C.) and Department of Biostatistics (C.S.), Indiana University School of Medicine, Indianapolis; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (C.-C.Y.); Fairbanks School of Public Health, School of Medicine, Indiana University, Indianapolis (C.S.); Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (M.C.F.); Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.); and Department of Medicine, Roudebush Veterans Affairs Medical Center, Indianapolis, IN (J.C.L.).
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28
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Affiliation(s)
- Arthur J Moss
- From the Division of Cardiology of the Department of Medicine, University of Rochester Medical Center, Rochester, NY.
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29
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Tayeh O. Reply to: The QT measurements after biventricular pacing, is it reliable? J Saudi Heart Assoc 2014; 26:233. [PMID: 25278728 DOI: 10.1016/j.jsha.2014.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Affiliation(s)
- Osama Tayeh
- Critical Care Medicine, Cairo University, Egypt
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Gomez JF, Cardona K, Romero L, Ferrero JM, Trenor B. Electrophysiological and structural remodeling in heart failure modulate arrhythmogenesis. 1D simulation study. PLoS One 2014; 9:e106602. [PMID: 25191998 PMCID: PMC4156355 DOI: 10.1371/journal.pone.0106602] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 08/05/2014] [Indexed: 01/24/2023] Open
Abstract
Background Heart failure is a final common pathway or descriptor for various cardiac pathologies. It is associated with sudden cardiac death, which is frequently caused by ventricular arrhythmias. Electrophysiological remodeling, intercellular uncoupling, fibrosis and autonomic imbalance have been identified as major arrhythmogenic factors in heart failure etiology and progression. Objective In this study we investigate in silico the role of electrophysiological and structural heart failure remodeling on the modulation of key elements of the arrhythmogenic substrate, i.e., electrophysiological gradients and abnormal impulse propagation. Methods Two different mathematical models of the human ventricular action potential were used to formulate models of the failing ventricular myocyte. This provided the basis for simulations of the electrical activity within a transmural ventricular strand. Our main goal was to elucidate the roles of electrophysiological and structural remodeling in setting the stage for malignant life-threatening arrhythmias. Results Simulation results illustrate how the presence of M cells and heterogeneous electrophysiological remodeling in the human failing ventricle modulate the dispersion of action potential duration and repolarization time. Specifically, selective heterogeneous remodeling of expression levels for the Na+/Ca2+ exchanger and SERCA pump decrease these heterogeneities. In contrast, fibroblast proliferation and cellular uncoupling both strongly increase repolarization heterogeneities. Conduction velocity and the safety factor for conduction are also reduced by the progressive structural remodeling during heart failure. Conclusion An extensive literature now establishes that in human ventricle, as heart failure progresses, gradients for repolarization are changed significantly by protein specific electrophysiological remodeling (either homogeneous or heterogeneous). Our simulations illustrate and provide new insights into this. Furthermore, enhanced fibrosis in failing hearts, as well as reduced intercellular coupling, combine to increase electrophysiological gradients and reduce electrical propagation. In combination these changes set the stage for arrhythmias.
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Affiliation(s)
- Juan F. Gomez
- Instituto de Investigación en Ingeniería Biomédica, Universitat Politècnica de València, Valencia, Spain
| | - Karen Cardona
- Instituto de Investigación en Ingeniería Biomédica, Universitat Politècnica de València, Valencia, Spain
| | - Lucia Romero
- Instituto de Investigación en Ingeniería Biomédica, Universitat Politècnica de València, Valencia, Spain
| | - Jose M. Ferrero
- Instituto de Investigación en Ingeniería Biomédica, Universitat Politècnica de València, Valencia, Spain
| | - Beatriz Trenor
- Instituto de Investigación en Ingeniería Biomédica, Universitat Politècnica de València, Valencia, Spain
- * E-mail:
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31
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Ruan L, Quan X, Li L, Bai R, Ni M, Xu R, Zhang C. Increasing gap junction coupling suppresses ibutilide-induced torsades de pointes. Exp Ther Med 2014; 7:1279-1284. [PMID: 24940425 PMCID: PMC3991525 DOI: 10.3892/etm.2014.1601] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 02/13/2014] [Indexed: 11/24/2022] Open
Abstract
Drug-induced torsades de pointes (TdP) is common with class III antiarrhythmic drugs. Increased transmural dispersion of repolarization (TDR) contributes significantly to the development of TdP. Gap junctions play an important role in maintaining TDR in long QT syndrome. The present study examined the effect of a gap junction enhancer, antiarrhythmic peptide 10 (AAP10), on ibutilide-induced TdP. Coronary-perfused rabbit ventricular wedge preparations were used to evaluate the effect of AAP10 on ibutilide-induced arrhythmia. Transmural electrocardiograms and action potentials were recorded simultaneously. Early afterdepolarizations (EADs), R-on-T extrasystole, TdP and changes in Tpeak-end (Tp-e) and the Tp-e/QT ratio were observed. Changes in the levels of non-phosphorylated connexin 43 (Cx43) were measured by immunoblotting. Compared with those in the control group, the QT interval, Tp-e/QT and incidence rates of EAD and TdP increased with augmented dephosphorylation in the ventricular wedge preparations perfused with ibutilide under conditions of hypokalemia and hypomagnesemia. In the presence of AAP10, the incidence rates of EAD and TdP were reduced and the Tp-e/QT ratio decreased, with a parallel reduction in the level of non-phosphorylated Cx43. The results indicate that AAP10 suppressed ibutilide-induced TdP under conditions of hypokalemia and hypomagnesemia by decreasing TDR. AAP10 reduced TDR, possibly by preventing the dephosphorylation of Cx43 and thereby increasing myocardial cell gap junction coupling.
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Affiliation(s)
- Lei Ruan
- Department of Gerontology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Xiaoqing Quan
- Department of Gerontology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Liandong Li
- Department of Gerontology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Rong Bai
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, P.R. China
| | - Mingke Ni
- Department of Gerontology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Rende Xu
- Department of Gerontology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Cuntai Zhang
- Department of Gerontology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
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32
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Polak S, Wiśniowska B, Fijorek K, Glinka A, Mendyk A. In vitro-in vivo extrapolation of drug-induced proarrhythmia predictions at the population level. Drug Discov Today 2013; 19:275-81. [PMID: 24140591 DOI: 10.1016/j.drudis.2013.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 09/16/2013] [Accepted: 10/09/2013] [Indexed: 01/25/2023]
Abstract
Drug cardiotoxicity is a serious issue for patients, regulators, pharmaceutical companies and health service payers because they are all affected by its consequences. Despite the wide range of data they generate, existing approaches for cardiac safety testing might not be adequate and sufficiently cost-effective, probably as a result of the complexity of the problem. For this reason, translational tools (based on biophysically detailed, mathematical models) allowing for in vitro-in vivo extrapolation are gaining increasing interest. This current review describes approaches that can be used for cardiac safety assessment at the population level, by accounting for various sources of variability including kinetics of the compound of interest.
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Affiliation(s)
- Sebastian Polak
- Unit of Pharmacoepidemiology and Pharmacoeconomics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland; Simcyp Limited, Blades Enterprise Centre, John Street, Sheffield, UK.
| | - Barbara Wiśniowska
- Unit of Pharmacoepidemiology and Pharmacoeconomics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland
| | - Kamil Fijorek
- Department of Statistics, Faculty of Management, Cracow University of Economics, Rakowicka 27 Street, 31-510 Kraków, Poland
| | - Anna Glinka
- Unit of Pharmacoepidemiology and Pharmacoeconomics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland
| | - Aleksander Mendyk
- Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland
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Brief endocardial surge of Ca2+ transient but monotonic suppression of action potential occurs during acute ischemia in canine ventricular tissue. Heart Rhythm 2013; 10:1201-8. [DOI: 10.1016/j.hrthm.2013.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Indexed: 11/22/2022]
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Bieganowska K, Sawicka-Parobczyk M, Bieganowski M, Piskorski J. Tpeak -tend interval in 12-lead electrocardiogram of healthy children and adolescents tpeak -tend interval in childhood. Ann Noninvasive Electrocardiol 2013; 18:344-51. [PMID: 23879274 DOI: 10.1111/anec.12035] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Tpeak (Tp) to the Tend (Te) interval is an index of transmural dispersion of repolarization. Prolongation of this interval predisposes to life-threatening ventricular arrhythmias in long QT syndrome, polymorphic catecholaminergic ventricular tachycardia, Brugada syndrome and short QT syndrome and may be an indicator of increased risk of sudden cardiac death. Very little is known about TpTe interval in children and adolescents. METHODS In 131 healthy children (64 girls) aged from 2.3 to 18.5 years (mean 9.1 years) the RR, QT, JT and TpTe intervals were measured manually in all leads of resting electrocardiogram (ECG). The statistical analysis were performed. RESULTS TpTe intervals vary significantly (P < 0.0001) between individual leads-the longest were in lead V3 , the shortest ones in leads III and V1 . Boys had longer TpTe intervals, with statistically significant differences in leads I, aVR and precordial V2 -V6 . Greater values were also observed in older children. TpTe dispersion varied from 6 to 80 ms (mean 38.6 ms ± 14.6 ms, median 40 ms) with no gender differences and greater values in older subjects (P = 0.003). In most leads, higher TpTe/QT and TpTe/JT ratios were seen in boys regardless of age. The TpTe intervals lengthens with lowering heart rate. CONCLUSIONS In healthy children and adolescents, TpTe intervals vary between individual leads of ECG, with the longest in lead V3 . The TpTe interval is longer in boys and in older children and prolongs as heart rate decelerates. TpTe/QT and TpTe/JT ratios are higher in boys. TpTe interval should be measured in precordial leads.
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Affiliation(s)
- Katarzyna Bieganowska
- Cardiology Department of the Children's Memorial Health Institute, 04-730 Warsaw, Poland.
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35
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Adeniran I, El Harchi A, Hancox JC, Zhang H. Proarrhythmia in KCNJ2-linked short QT syndrome: insights from modelling. Cardiovasc Res 2012; 94:66-76. [DOI: 10.1093/cvr/cvs082] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Torsion of the human left ventricle: experimental analysis and computational modeling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 107:112-21. [PMID: 21791224 DOI: 10.1016/j.pbiomolbio.2011.07.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 07/01/2011] [Indexed: 11/22/2022]
Abstract
We set a twofold investigation: we assess left ventricular (LV) rotation and twist in the human heart through 3D-echocardiographic speckle tracking, and use representative experimental data as benchmark with respect to numerical results obtained by solving our mechanical model of the LV. We aim at new insight into the relationships between myocardial contraction patterns and the overall behavior at the scale of the whole organ. It is concluded that torsional rotation is sensitive to transmural gradients of contractility which is assumed linearly related to action potential duration (APD). Pressure-volume loops and other basic strain measures are not affected by these gradients. Therefore, realistic torsional behavior of human LV may indeed correspond to the electrophysiological and functional differences between endocardial and epicardial cells recently observed in non-failing hearts. Future investigations need now to integrate the mechanical model proposed here with minimal models of human ventricular APD to drive excitation-contraction coupling transmurally.
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Abstract
Cardiovascular diseases are among the leading causes of death in the developed world. Developing novel therapies for diseases like heart failure is crucial, but this is hampered by the high attrition rate in drug development. The withdrawal of drugs at the final hurdle of approval is mostly because of their unpredictable effects on normal cardiac rhythm. The advent of cardiac computational modeling in the last 5 decades has aided the understanding of heart function significantly. Recently, these models increasingly have been applied toward designing and understanding therapies for cardiac disease. This article will discuss how cellular models of electrophysiology, cell signaling, and metabolism have been used to investigate pharmacologic therapies for cardiac diseases including arrhythmia, ischemia, and heart failure.
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Affiliation(s)
- Robert K. Amanfu
- Department of Biomedical Engineering, Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey J. Saucerman
- Department of Biomedical Engineering, Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
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Singh BN, Cingolani E. A new agent for atrial fibrillation: electrophysiological properties of dronedarone. J Cardiovasc Pharmacol Ther 2010; 15:6S-14S. [PMID: 21098415 DOI: 10.1177/1074248410377618] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Although originally synthesized as an antianginal compound, amiodarone has emerged as an effective antiarrhythmic for both supraventricular and ventricular arrhythmias. Over the decades, the properties, the effectiveness, the merits as well as the shortcomings of the compound have been well established. The major limitations of this agent are mainly due to the systemic side effects seen with prolonged therapy. Many of the toxic effects observed are primarily caused by the high iodine content present in the amiodarone molecule. Dronedarone, the first noniodinated amiodarone congener, has been developed largely to obtain the antiarrhythmic efficacy in the control of atrial fibrillation without the known adverse side effects of dronedarone. In this part of the supplement, the focus is the electrophysiological effects of dronedarone with the characterization in normal cardiac cells, in animal models of disease, as well as in human studies.
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Affiliation(s)
- Bramah N Singh
- Division of Cardiology, Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA, USA.
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