101
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Frommeyer G, Brücher B, von der Ahe H, Kaese S, Dechering DG, Kochhäuser S, Bogossian H, Milberg P, Eckardt L. Low proarrhythmic potential of citalopram and escitalopram in contrast to haloperidol in an experimental whole-heart model. Eur J Pharmacol 2016; 788:192-199. [PMID: 27328775 DOI: 10.1016/j.ejphar.2016.06.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/10/2016] [Accepted: 06/17/2016] [Indexed: 11/28/2022]
Abstract
In several case reports proarrhythmic effects of citalopram and escitalopram have been reported. Systematic analyses on prorarrhythmic effects of these drugs are not yet available. The aim of the present study was to investigate if application of citalopram, escitalopram or haloperidol provokes polymorphic ventricular tachycardia in a sensitive model of proarrhythmia. In isolated rabbit hearts monophasic action potentials and ECG showed a significant QT-prolongation after application of citalopram (2µM: +47ms, 4µM: +56ms, P<0.05) accompanied by an increase of action potential duration (APD) but not dispersion of repolarization. Reduced potassium concentration in bradycardic AV-blocked hearts provoked early afterdepolarizations (EAD) in 2 of 12 hearts but no polymorphic ventricular tachycardia (pVT). Application of escitalopram also increased QT-interval (2µM: +3ms, 4µM: +30ms, P<0.05) and APD without effects on dispersion. 3 of 10 hearts showed EAD and pVT in 2 of 10 hearts (32 episodes). The results were compared to 12 rabbits treated with haloperidol which led to an increase in QT-interval (1µM:+62ms; 2µM:+96ms; P<0.01), APD and dispersion (1µM:+15ms, 2µM:+40ms; P<0.01) and induced EAD in all 12 and pVT in 10 of 12 hearts (152 episodes). Citalopram and escitalopram demonstrated a rather safe electrophysiologic profile despite significant QT prolongation. In contrast, haloperidol led to significant increase of dispersion of repolarization while this parameter remained stable under the influence of citalopram or escitalopram. These results imply that application of citalopram or escitalopram is not as proarrhythmic as some case reports might suggest while haloperidol is torsadogenic.
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Affiliation(s)
- Gerrit Frommeyer
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany.
| | - Benedict Brücher
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany
| | - Henning von der Ahe
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany
| | - Sven Kaese
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany
| | - Dirk G Dechering
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany
| | - Simon Kochhäuser
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany
| | - Harilaos Bogossian
- Märkische Kliniken GmbH, Department of Cardiology and Angiology, Klinikum Lüdenscheid, University of Witten-Herdecke, Germany
| | - Peter Milberg
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany
| | - Lars Eckardt
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany
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102
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Baumert M, Porta A, Vos MA, Malik M, Couderc JP, Laguna P, Piccirillo G, Smith GL, Tereshchenko LG, Volders PGA. QT interval variability in body surface ECG: measurement, physiological basis, and clinical value: position statement and consensus guidance endorsed by the European Heart Rhythm Association jointly with the ESC Working Group on Cardiac Cellular Electrophysiology. Europace 2016; 18:925-44. [PMID: 26823389 PMCID: PMC4905605 DOI: 10.1093/europace/euv405] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 11/05/2015] [Indexed: 12/20/2022] Open
Abstract
This consensus guideline discusses the electrocardiographic phenomenon of beat-to-beat QT interval variability (QTV) on surface electrocardiograms. The text covers measurement principles, physiological basis, and clinical value of QTV. Technical considerations include QT interval measurement and the relation between QTV and heart rate variability. Research frontiers of QTV include understanding of QTV physiology, systematic evaluation of the link between QTV and direct measures of neural activity, modelling of the QTV dependence on the variability of other physiological variables, distinction between QTV and general T wave shape variability, and assessing of the QTV utility for guiding therapy. Increased QTV appears to be a risk marker of arrhythmic and cardiovascular death. It remains to be established whether it can guide therapy alone or in combination with other risk factors. QT interval variability has a possible role in non-invasive assessment of tonic sympathetic activity.
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Affiliation(s)
- Mathias Baumert
- School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA, Australia
| | - Alberto Porta
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marek Malik
- St Paul's Cardiac Electrophysiology, University of London, and National Heart and Lung Institute, Imperial College, Dovehouse Street, London SW3 6LY, UK
| | - Jean-Philippe Couderc
- Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA
| | - Pablo Laguna
- Zaragoza University and CIBER-BBN, Zaragoza, Spain
| | - Gianfranco Piccirillo
- Dipartimento di Scienze Cardiovascolari, Respiratorie, Nefrologiche, Anestesiologiche e Geriatriche, Università 'La Sapienza' Rome, Rome, Italy
| | - Godfrey L Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Larisa G Tereshchenko
- Oregon Health and Science University, Knight Cardiovascular Institute, Portland, OR, USA
| | - Paul G A Volders
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
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103
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Lancaster MC, Sobie EA. Improved Prediction of Drug-Induced Torsades de Pointes Through Simulations of Dynamics and Machine Learning Algorithms. Clin Pharmacol Ther 2016; 100:371-9. [PMID: 26950176 DOI: 10.1002/cpt.367] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/15/2016] [Accepted: 03/03/2016] [Indexed: 12/21/2022]
Abstract
The ventricular arrhythmia Torsades de Pointes (TdP) is a common form of drug-induced cardiotoxicity, but prediction of this arrhythmia remains an unresolved issue in drug development. Current assays to evaluate arrhythmia risk are limited by poor specificity and a lack of mechanistic insight. We addressed this important unresolved issue through a novel computational approach that combined simulations of drug effects on dynamics with statistical analysis and machine-learning. Drugs that blocked multiple ion channels were simulated in ventricular myocyte models, and metrics computed from the action potential and intracellular (Ca(2+) ) waveform were used to construct classifiers that distinguished between arrhythmogenic and nonarrhythmogenic drugs. We found that: (1) these classifiers provide superior risk prediction; (2) drug-induced changes to both the action potential and intracellular (Ca(2+) ) influence risk; and (3) cardiac ion channels not typically assessed may significantly affect risk. Our algorithm demonstrates the value of systematic simulations in predicting pharmacological toxicity.
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Affiliation(s)
- M Cummins Lancaster
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - E A Sobie
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
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104
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Major P, Baczkó I, Hiripi L, Odening KE, Juhász V, Kohajda Z, Horváth A, Seprényi G, Kovács M, Virág L, Jost N, Prorok J, Ördög B, Doleschall Z, Nattel S, Varró A, Bősze Z. A novel transgenic rabbit model with reduced repolarization reserve: long QT syndrome caused by a dominant-negative mutation of the KCNE1 gene. Br J Pharmacol 2016; 173:2046-61. [PMID: 27076034 DOI: 10.1111/bph.13500] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 03/25/2016] [Accepted: 04/01/2016] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND AND PURPOSE The reliable assessment of proarrhythmic risk of compounds under development remains an elusive goal. Current safety guidelines focus on the effects of blocking the KCNH2/HERG ion channel-in tissues and animals with intact repolarization. Novel models with better predictive value are needed that more closely reflect the conditions in patients with cardiac remodelling and reduced repolarization reserve. EXPERIMENTAL APPROACH We have developed a model for the long QT syndrome type-5 in rabbits (LQT5 ) with cardiac-specific overexpression of a mutant (G52R) KCNE1 β-subunit of the channel that carries the slow delayed-rectifier K(+) -current (IKs ). ECG parameters, including short-term variability of the QT interval (STVQT ), a biomarker for proarrhythmic risk, and arrhythmia development were recorded. In vivo, arrhythmia susceptibility was evaluated by i.v. administration of the IKr blocker dofetilide. K(+) currents were measured with the patch-clamp technique. KEY RESULTS Patch-clamp studies in ventricular myocytes isolated from LQT5 rabbits revealed accelerated IKs and IKr deactivation kinetics. At baseline, LQT5 animals exhibited slightly but significantly prolonged heart-rate corrected QT index (QTi) and increased STVQT . Dofetilide provoked Torsade-de-Pointes arrhythmia in a greater proportion of LQT5 rabbits, paralleled by a further increase in STVQT . CONCLUSION AND IMPLICATIONS We have created a novel transgenic LQT5 rabbit model with increased susceptibility to drug-induced arrhythmias that may represent a useful model for testing proarrhythmic potential and for investigations of the mechanisms underlying arrhythmias and sudden cardiac death due to repolarization disturbances.
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Affiliation(s)
- Péter Major
- Rabbit Genome and Biomodel Group, NARIC - Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - István Baczkó
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - László Hiripi
- Rabbit Genome and Biomodel Group, NARIC - Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Katja E Odening
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Freiburg, Germany
| | - Viktor Juhász
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Zsófia Kohajda
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - András Horváth
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - György Seprényi
- Department of Biology, University of Szeged, Szeged, Hungary
| | - Mária Kovács
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - László Virág
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Norbert Jost
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - János Prorok
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Balázs Ördög
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Zoltán Doleschall
- Department of Pathogenetics, National Institute of Oncology, Budapest, Hungary
| | - Stanley Nattel
- Department of Medicine, Montreal Heart Institute, Université de Montréal, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada.,Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - András Varró
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - Zsuzsanna Bősze
- Rabbit Genome and Biomodel Group, NARIC - Agricultural Biotechnology Institute, Gödöllő, Hungary
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105
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Baczkó I, Jost N, Virág L, Bősze Z, Varró A. Rabbit models as tools for preclinical cardiac electrophysiological safety testing: Importance of repolarization reserve. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 121:157-68. [PMID: 27208697 DOI: 10.1016/j.pbiomolbio.2016.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/01/2016] [Indexed: 01/26/2023]
Abstract
It is essential to more reliably assess the pro-arrhythmic liability of compounds in development. Current guidelines for pre-clinical and clinical testing of drug candidates advocate the use of healthy animals/tissues and healthy individuals and focus on the test compound's ability to block the hERG current and prolong cardiac ventricular repolarization. Also, pre-clinical safety tests utilize several species commonly used in cardiac electrophysiological studies. In this review, important species differences in cardiac ventricular repolarizing ion currents are considered, followed by the discussion on electrical remodeling associated with chronic cardiovascular diseases that leads to altered ion channel and transporter expression and densities in pathological settings. We argue that the choice of species strongly influences experimental outcome and extrapolation of results to human clinical settings. We suggest that based on cardiac cellular electrophysiology, the rabbit is a useful species for pharmacological pro-arrhythmic investigations. In addition to healthy animals and tissues, the use of animal models (e.g. those with impaired repolarization reserve) is suggested that more closely resemble subsets of patients exhibiting increased vulnerability towards the development of ventricular arrhythmias and sudden cardiac death.
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Affiliation(s)
- István Baczkó
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Dóm tér 12., 6720 Szeged, Hungary.
| | - Norbert Jost
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Dóm tér 12., 6720 Szeged, Hungary; MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Dóm tér 12., 6720 Szeged, Hungary
| | - László Virág
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Dóm tér 12., 6720 Szeged, Hungary
| | - Zsuzsanna Bősze
- Rabbit Genome and Biomodel Group, NARIC-Agricultural Biotechnology Institute, 2100 Gödöllő, Hungary
| | - András Varró
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Dóm tér 12., 6720 Szeged, Hungary; MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Dóm tér 12., 6720 Szeged, Hungary
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106
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Stams TR, Oosterhoff P, Heijdel A, Dunnink A, Beekman JD, van der Nagel R, van Rijen HV, van der Heyden MA, Vos MA. Beat-to-Beat Variability in Preload Unmasks Latent Risk of Torsade de Pointes in Anesthetized Chronic Atrioventricular Block Dogs. Circ J 2016; 80:1336-45. [PMID: 27151565 DOI: 10.1253/circj.cj-15-1335] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Beat-to-beat variability in ventricular repolarization (BVR) associates with increased arrhythmic risk. Proarrhythmic remodeling in the dog with chronic AV-block (CAVB) compromises repolarization reserve and associates with increased BVR, which further increases upon dofetilide infusion and correlates with Torsade de Pointes (TdP) arrhythmias. It was hypothesized that these pro-arrhythmia-associated increases in BVR are induced by beat-to-beat variability in preload. METHODS AND RESULTS Left ventricular monophasic action potential duration (LVMAPD) was recorded in acute (AAVB) and CAVB dogs, before and after dofetilide infusion. BVR was quantified as short-term variability of LVMAPD. The PQ-interval was controlled by pacing: either a constant or an alternating preload pattern was established, verified by PV-loop. The effect of the stretch-activated channel blocker, streptomycin, on BVR was evaluated in a second CAVB group. At alternating preload only, BVR was increased after proarrhythmic remodeling (0.45±0.14 ms AAVB vs. 2.2±1.1 ms CAVB, P<0.01). At CAVB, but not at AAVB, dofetilide induced significant proarrhythmia. Preload variability augmented the dofetilide-induced BVR increase at CAVB (+1.5±0.8 ms vs. +0.9±0.9 ms, P=0.058). In the second group, the increase in baseline BVR by alternating preload (0.3±0.03 ms to 1.0±0.8 ms, P<0.01) was abolished by streptomycin (0.5±0.2 ms, P<0.05). CONCLUSIONS In CAVB dogs, the inverse relation between BVR and repolarization reserve originates from an augmented sensitivity of ventricular repolarization to beat-to-beat preload changes. Stretch-activated channels appear to be involved in the mechanism of BVR. (Circ J 2016; 80: 1336-1345).
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Affiliation(s)
- Thom Rg Stams
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center
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107
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Izumi-Nakaseko H, Nakamura Y, Cao X, Wada T, Ando K, Sugiyama A. Possibility as an anti-cancer drug of astemizole: Evaluation of arrhythmogenicity by the chronic atrioventricular block canine model. J Pharmacol Sci 2016; 131:150-3. [PMID: 27262902 DOI: 10.1016/j.jphs.2016.04.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 04/19/2016] [Accepted: 04/25/2016] [Indexed: 01/10/2023] Open
Abstract
Since astemizole in an oral dose of 50 mg/kg/day was recently reported to exert anti-cancer effect in mice, we evaluated its proarrhythmic potential using the atrioventricular block dogs in order to clarify its cardiac safety profile. An oral dose of 3 mg/kg prolonged the QT interval without affecting the QTc (n = 4), whereas that of 30 mg/kg increased the short-term variability of repolarization and induced premature ventricular contractions in each animal, resulting in the onset of torsade de pointes in 1 animal (n = 4). Thus, proarrhythmic dose of astemizole would be lower than anti-cancer one, limiting its re-profiling as an anti-cancer drug.
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Affiliation(s)
- Hiroko Izumi-Nakaseko
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143-8540, Japan
| | - Yuji Nakamura
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143-8540, Japan
| | - Xin Cao
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143-8540, Japan
| | - Takeshi Wada
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143-8540, Japan
| | - Kentaro Ando
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143-8540, Japan
| | - Atsushi Sugiyama
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143-8540, Japan.
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108
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Nakamura Y, Sasaki R, Cao X, Wada T, Hamaguchi S, Izumi-Nakaseko H, Ando K, Tanaka H, Takahara A, Sugiyama A. Intravenous anti-influenza drug oseltamivir will not induce torsade de pointes: Evidences from proarrhythmia model and action-potential assay. J Pharmacol Sci 2016; 131:72-5. [PMID: 27174864 DOI: 10.1016/j.jphs.2016.04.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 01/06/2016] [Accepted: 04/13/2016] [Indexed: 10/21/2022] Open
Abstract
We evaluated proarrhythmic risk of intravenous oseltamivir with chronic atrioventricular block canine model (n = 4) and action-potential assay on guinea-pig right ventricle (n = 5). Oseltamivir in doses of 3-30 mg/kg, i.v. did not induce torsade de pointes in the canine model, whereas that in concentrations of 30-300 μM decreased maximum rate of phase 0 depolarization, shortened action potential duration at 30%, 60% and 90% repolarization levels, but prolonged difference in action-potential duration between 30% and 90% repolarization levels in a concentration-related manner. These results indicate that oseltamivir will not induce torsade de pointes clinically, since it inhibits both inward and outward currents.
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Affiliation(s)
- Yuji Nakamura
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo 143-8540, Japan
| | - Rieko Sasaki
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Chiba 274-8510, Japan
| | - Xin Cao
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo 143-8540, Japan
| | - Takeshi Wada
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo 143-8540, Japan
| | - Shogo Hamaguchi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Chiba 274-8510, Japan
| | - Hiroko Izumi-Nakaseko
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo 143-8540, Japan
| | - Kentaro Ando
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo 143-8540, Japan
| | - Hikaru Tanaka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Chiba 274-8510, Japan
| | - Akira Takahara
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Chiba 274-8510, Japan
| | - Atsushi Sugiyama
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo 143-8540, Japan.
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109
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Ohara H, Nakamura Y, Watanabe Y, Cao X, Yamazaki Y, Izumi-Nakaseko H, Ando K, Yamazaki H, Yamazaki J, Ikeda T, Sugiyama A. Azithromycin Can Prolong QT Interval and Suppress Ventricular Contraction, but Will Not Induce Torsade de Pointes. Cardiovasc Toxicol 2016; 15:232-40. [PMID: 25367413 DOI: 10.1007/s12012-014-9289-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Azithromycin has been reported to increase the risk of death from cardiovascular causes among patients with high baseline risk. Since the information is still limited to bridge the gap between electrophysiological properties of azithromycin in vitro and cardiac death in patients, we initially assessed its electropharmacological effects in doses of 3 and 30 mg/kg, i.v., with the halothane-anesthetized dogs (n = 4). The low dose provided 5.2 times higher than the therapeutic concentration, whereas the high dose attained 17.0 times higher. The high dose delayed the ventricular repolarization in a reverse use-dependent manner, reflecting blockade of the rapid component of delayed rectifier K(+) current, and the potency was relatively weak; namely, maximum change in QTc was +20 ms (+5.6%). The high dose also induced the negative inotropic effect possibly through Ca(2+) channel-independent pathway. In order to clarify proarrhythmic risk, 30 mg/kg, i.v., of azithromycin was examined with the chronic atrioventricular block dogs (n = 4). Azithromycin neither induced torsade de pointes nor affected beat-to-beat variability of repolarization. Thus, azithromycin can be considered to lack proarrhythmic potential, but caution has to be paid on its use for patients with left ventricular dysfunction.
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Affiliation(s)
- Hiroshi Ohara
- Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-Nishi, Ota-ku, Tokyo, 143-8540, Japan
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110
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Meo M, Meste O, Signore S, Sorrentino A, Cannata A, Zhou Y, Matsuda A, Luciani M, Kannappan R, Goichberg P, Leri A, Anversa P, Rota M. Reduction in Kv Current Enhances the Temporal Dispersion of the Action Potential in Diabetic Myocytes: Insights From a Novel Repolarization Algorithm. J Am Heart Assoc 2016; 5:e003078. [PMID: 26896476 PMCID: PMC4802457 DOI: 10.1161/jaha.115.003078] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 01/02/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND Diabetes is associated with prolongation of the QT interval of the electrocardiogram and enhanced dispersion of ventricular repolarization, factors that, together with atherosclerosis and myocardial ischemia, may promote the occurrence of electrical disorders. Thus, we tested the possibility that alterations in transmembrane ionic currents reduce the repolarization reserve of myocytes, leading to action potential (AP) prolongation and enhanced beat-to-beat variability of repolarization. METHODS AND RESULTS Diabetes was induced in mice with streptozotocin (STZ), and effects of hyperglycemia on electrical properties of whole heart and myocytes were studied with respect to an untreated control group (Ctrl) using electrocardiographic recordings in vivo, ex vivo perfused hearts, and single-cell patch-clamp analysis. Additionally, a newly developed algorithm was introduced to obtain detailed information of the impact of high glucose on AP profile. Compared to Ctrl, hyperglycemia in STZ-treated animals was coupled with prolongation of the QT interval, enhanced temporal dispersion of electrical recovery, and susceptibility to ventricular arrhythmias, defects observed, in part, in the Akita mutant mouse model of type I diabetes. AP was prolonged and beat-to-beat variability of repolarization was enhanced in diabetic myocytes, with respect to Ctrl cells. Density of Kv K(+) and L-type Ca(2+) currents were decreased in STZ myocytes, in comparison to cells from normoglycemic mice. Pharmacological reduction of Kv currents in Ctrl cells lengthened AP duration and increased temporal dispersion of repolarization, reiterating features identified in diabetic myocytes. CONCLUSIONS Reductions in the repolarizing K(+) currents may contribute to electrical disturbances of the diabetic heart.
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Affiliation(s)
- Marianna Meo
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Olivier Meste
- Laboratoire d'Informatique, Signaux et Systèmes de Sophia Antipolis (I3S), Université Nice Sophia Antipolis, CNRS, Nice, France
| | - Sergio Signore
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Andrea Sorrentino
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Antonio Cannata
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Yu Zhou
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Alex Matsuda
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA Fondazione Cardiocentro Ticino, University of Zurich, Lugano, Switzerland
| | - Marco Luciani
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Ramaswamy Kannappan
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Polina Goichberg
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Annarosa Leri
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA Fondazione Cardiocentro Ticino, University of Zurich, Lugano, Switzerland
| | - Piero Anversa
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA Fondazione Cardiocentro Ticino, University of Zurich, Lugano, Switzerland
| | - Marcello Rota
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA Department of Physiology, New York Medical College, Valhalla, NY
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111
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Champeroux P, Le Guennec JY, Jude S, Laigot C, Maurin A, Sola ML, Fowler JSL, Richard S, Thireau J. The high frequency relationship: implications for torsadogenic hERG blockers. Br J Pharmacol 2016; 173:601-12. [PMID: 26589499 DOI: 10.1111/bph.13391] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 11/11/2015] [Accepted: 11/17/2015] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Ventricular arrhythmias induced by human ether-a-go-go related gene (hERG; Kv 11.1 channel) blockers are a consequence of alterations in ventricular repolarisation in association with high-frequency (HF) oscillations, which act as a primary trigger; the autonomic nervous system plays a modulatory role. In the present study, we investigated the role of β1 -adrenoceptors in the HF relationship between magnitude of heart rate and QT interval changes within discrete 10 s intervals (sorted into 5 bpm heart rate increments) and its implications for torsadogenic hERG blockers. EXPERIMENTAL APPROACH The HF relationship was studied under conditions of autonomic blockade with atenolol (β1 -adrenoceptor blocker) in the absence or presence of five hERG blockers in beagle dogs. In total, the effects of 14 hERG blockers on the HF relationship were investigated. KEY RESULTS All the torsadogenic hERG blockers tested caused a vertical shift in the HF relationship, while hERG blockers associated with a low risk of Torsades de Pointes did not cause any vertical shift. Atenolol completely prevented the effects four torsadogenic agents (quinidine, thioridazine, risperidone and terfenadine) on the HF relationship, but only partially reduced those of dofetilide, leading to the characterization of two types of torsadogenic agent. CONCLUSIONS AND IMPLICATIONS Analysis of the vertical shift in the HF relationship demonstrated that signs of transient sympathetic activation during HF oscillations in the presence of torsadogenic hERG blockers are mediated by β1 -adrenoceptors. We suggest the HF relationship as a new biomarker for assessing Torsades de pointes liability, with potential implications in both preclinical studies and the clinic.
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Affiliation(s)
- P Champeroux
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - J Y Le Guennec
- Laboratoire PHYMEDEXP, Physiologie et Médecine Expérimentale, Cœur et Muscles, INSERM U1046, CNRS UMR 9214, Université de Montpellier, CHU Arnaud de Villeneuve, 371 Avenue du doyen G. Giraud, 34295, Montpellier cedex 05, France
| | - S Jude
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - C Laigot
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - A Maurin
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - M L Sola
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - J S L Fowler
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - S Richard
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - J Thireau
- Laboratoire PHYMEDEXP, Physiologie et Médecine Expérimentale, Cœur et Muscles, INSERM U1046, CNRS UMR 9214, Université de Montpellier, CHU Arnaud de Villeneuve, 371 Avenue du doyen G. Giraud, 34295, Montpellier cedex 05, France
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112
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Ramakrishna H, O’Hare M, Mookadam F, Gutsche JT, Shah R, Augoustides JG. Sudden Cardiac Death and Disorders of the QT Interval: Anesthetic Implications and Focus on Perioperative Management. J Cardiothorac Vasc Anesth 2015; 29:1723-33. [DOI: 10.1053/j.jvca.2015.07.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Indexed: 12/19/2022]
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113
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Antoons G, Johnson DM, Dries E, Santiago DJ, Ozdemir S, Lenaerts I, Beekman JDM, Houtman MJC, Sipido KR, Vos MA. Calcium release near L-type calcium channels promotes beat-to-beat variability in ventricular myocytes from the chronic AV block dog. J Mol Cell Cardiol 2015; 89:326-34. [PMID: 26454162 DOI: 10.1016/j.yjmcc.2015.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 09/08/2015] [Accepted: 10/06/2015] [Indexed: 11/25/2022]
Abstract
Beat-to-beat variability of ventricular repolarization (BVR) has been proposed as a strong predictor of Torsades de Pointes (TdP). BVR is also observed at the myocyte level, and a number of studies have shown the importance of calcium handling in influencing this parameter. The chronic AV block (CAVB) dog is a model of TdP arrhythmia in cardiac hypertrophy, and myocytes from these animals show extensive remodeling, including of Ca(2+) handling. This remodeling process also leads to increased BVR. We aimed to determine the role that (local) Ca(2+) handling plays in BVR. In isolated LV myocytes an exponential relationship was observed between BVR magnitude and action potential duration (APD) at baseline. Inhibition of Ca(2+) release from sarcoplasmic reticulum (SR) with thapsigargin resulted in a reduction of [Ca(2+)]i, and of both BVR and APD. Increasing ICaL in the presence of thapsigargin restored APD but BVR remained low. In contrast, increasing ICaL with preserved Ca(2+) release increased both APD and BVR. Inhibition of Ca(2+) release with caffeine, as with thapsigargin, reduced BVR despite maintained APD. Simultaneous inhibition of Na(+)/Ca(2+) exchange and ICaL decreased APD and BVR to similar degrees, whilst increasing diastolic Ca(2+). Buffering of Ca(2+) transients with BAPTA reduced BVR for a given APD to a greater extent than buffering with EGTA, suggesting subsarcolemmal Ca(2+) transients modulated BVR to a larger extent than the cytosolic Ca(2+) transient. In conclusion, BVR in hypertrophied dog myocytes, at any APD, is strongly dependent on SR Ca(2+) release, which may act through modulation of the l-type Ca(2+) current in a subsarcolemmal microdomain.
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Affiliation(s)
- Gudrun Antoons
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands; Department of Physiology, Maastricht University, Maastricht, The Netherlands
| | - Daniel M Johnson
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium
| | - Eef Dries
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium
| | - Demetrio J Santiago
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium
| | - Semir Ozdemir
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium; Department of Biophysics, Akdeniz University, Antalya, Turkey
| | - Ilse Lenaerts
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium
| | - Jet D M Beekman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Marien J C Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Karin R Sipido
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium.
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
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114
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Altomare C, Bartolucci C, Sala L, Bernardi J, Mostacciuolo G, Rocchetti M, Severi S, Zaza A. I
Kr
Impact on Repolarization and Its Variability Assessed by Dynamic Clamp. Circ Arrhythm Electrophysiol 2015; 8:1265-75. [DOI: 10.1161/circep.114.002572] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 06/16/2015] [Indexed: 01/23/2023]
Abstract
Background—
Repolarization and its stability are exquisitely sensitive to
I
Kr
features. Information on the relative importance of specific
I
Kr
abnormalities is missing and would assist in the evaluation of arrhythmogenic risk.
Methods and Results—
In single guinea-pig myocytes, endogenous
I
Kr
was replaced by modeled
I
Kr
(m
I
Kr
) by dynamic clamp (DC) at a cycle length of 1 s. m
I
Kr
parameters were systematically modified, and the resulting changes in action potential duration (APD) and its short term variability (SD1) were measured. We observed that (1)
I
Kr
blockade increased SD1 more than expected by its dependency on APD; (2) m
I
Kr
completely reversed APD and SD1 changes caused by
I
Kr
blockade; (3) repolarization was most sensitive to inactivation shifts, which affected APD and SD1 concordantly; (4) activation shifts of the same magnitude had marginal impact on APD, but only when reducing m
I
Kr
, they significantly increased SD1; (5) changes in maximal conductance resulted in a pattern similar to that of activation shifts.
Conclusions—
The largest effect on repolarization and its stability are expected from changes in
I
Kr
inactivation. APD is less sensitive to changes in other
I
Kr
gating parameters, which are better revealed by SD1 changes. SD1 may be more sensitive than APD in detecting
I
Kr
-dependent repolarization abnormalities.
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Affiliation(s)
- Claudia Altomare
- From the Department of Biotechnologies & Biosciences, University of Milano-Bicocca, Milano (C.A., L.S., J.B., G.M., M.R., A.Z.); and Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy (C.B., S.S.)
| | - Chiara Bartolucci
- From the Department of Biotechnologies & Biosciences, University of Milano-Bicocca, Milano (C.A., L.S., J.B., G.M., M.R., A.Z.); and Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy (C.B., S.S.)
| | - Luca Sala
- From the Department of Biotechnologies & Biosciences, University of Milano-Bicocca, Milano (C.A., L.S., J.B., G.M., M.R., A.Z.); and Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy (C.B., S.S.)
| | - Joyce Bernardi
- From the Department of Biotechnologies & Biosciences, University of Milano-Bicocca, Milano (C.A., L.S., J.B., G.M., M.R., A.Z.); and Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy (C.B., S.S.)
| | - Gaspare Mostacciuolo
- From the Department of Biotechnologies & Biosciences, University of Milano-Bicocca, Milano (C.A., L.S., J.B., G.M., M.R., A.Z.); and Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy (C.B., S.S.)
| | - Marcella Rocchetti
- From the Department of Biotechnologies & Biosciences, University of Milano-Bicocca, Milano (C.A., L.S., J.B., G.M., M.R., A.Z.); and Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy (C.B., S.S.)
| | - Stefano Severi
- From the Department of Biotechnologies & Biosciences, University of Milano-Bicocca, Milano (C.A., L.S., J.B., G.M., M.R., A.Z.); and Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy (C.B., S.S.)
| | - Antonio Zaza
- From the Department of Biotechnologies & Biosciences, University of Milano-Bicocca, Milano (C.A., L.S., J.B., G.M., M.R., A.Z.); and Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy (C.B., S.S.)
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115
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Morvay N, Baczkó I, Sztojkov-Ivanov A, Falkay G, Papp JG, Varró A, Leprán I. Long-term pretreatment with desethylamiodarone (DEA) or amiodarone (AMIO) protects against coronary artery occlusion induced ventricular arrhythmias in conscious rats. Can J Physiol Pharmacol 2015; 93:773-7. [DOI: 10.1139/cjpp-2014-0530] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this investigation was to compare the effectiveness of long-term pretreatment with amiodarone (AMIO) and its active metabolite desethylamiodarone (DEA) on arrhythmias induced by acute myocardial infarction in rats. Acute myocardial infarction was induced in conscious, male, Sprague–Dawley rats by pulling a previously inserted loose silk loop around the left main coronary artery. Long-term oral pretreatment with AMIO (30 or 100 mg·(kg body mass)−1·day−1, loading dose 100 or 300 mg·kg−1 for 3 days) or DEA (15 or 50 mg·kg−1·day−1, loading dose 100 or 300 mg·kg−1 for 3 days), was applied for 1 month before the coronary artery occlusion. Chronic oral treatment with DEA (50 mg·kg−1·day−1) resulted in a similar myocardial DEA concentration as chronic AMIO treatment (100 mg·kg−1·day−1) in rats (7.4 ± 0.7 μg·g−1 and 8.9 ± 2.2 μg·g−1). Both pretreatments in the larger doses significantly improved the survival rate during the acute phase of experimental myocardial infarction (82% and 64% by AMIO and DEA, respectively, vs. 31% in controls). Our results demonstrate that chronic oral treatment with DEA resulted in similar cardiac tissue levels to that of chronic AMIO treatment, and offered an equivalent degree of antiarrhythmic effect against acute coronary artery ligation induced ventricular arrhythmias in conscious rats.
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Affiliation(s)
- Nikolett Morvay
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6701 Szeged, Dóm tér 12, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6701 Szeged, Dóm tér 12, Hungary
| | - Anita Sztojkov-Ivanov
- Department of Pharmacodynamics and Biopharmacy, Faculty of Pharmacy, University of Szeged, Hungary
| | - György Falkay
- Department of Pharmacodynamics and Biopharmacy, Faculty of Pharmacy, University of Szeged, Hungary
| | - Julius Gy. Papp
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6701 Szeged, Dóm tér 12, Hungary
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6701 Szeged, Dóm tér 12, Hungary
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - István Leprán
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6701 Szeged, Dóm tér 12, Hungary
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116
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Orosz A, Baczkó I, Nagy V, Gavallér H, Csanády M, Forster T, Papp JG, Varró A, Lengyel C, Sepp R. Short-term beat-to-beat variability of the QT interval is increased and correlates with parameters of left ventricular hypertrophy in patients with hypertrophic cardiomyopathy. Can J Physiol Pharmacol 2015; 93:765-72. [DOI: 10.1139/cjpp-2014-0526] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Stratification models for the prediction of sudden cardiac death (SCD) are inappropriate in patients with hypertrophic cardiomyopathy (HCM). We investigated conventional electrocardiogram (ECG) repolarization parameters and the beat-to-beat short-term QT interval variability (QT-STV), a new parameter of proarrhythmic risk, in 37 patients with HCM (21 males, average age 48 ± 15 years). Resting ECGs were recorded for 5 min and the frequency corrected QT interval (QTc), QT dispersion (QTd), beat-to-beat short-term variability of QT interval (QT-STV), and the duration of terminal part of T waves (Tpeak–Tend) were calculated. While all repolarization parameters were significantly increased in patients with HCM compared with the controls (QTc, 488 ± 61 vs. 434 ± 23 ms, p < 0.0001; QT-STV, 4.5 ± 2 vs. 3.2 ± 1 ms, p = 0.0002; Tpeak–Tend duration, 107 ± 27 vs. 91 ± 10 ms, p = 0.0015; QTd, 47 ± 17 vs. 34 ± 9 ms, p = 0.0002), QT-STV had the highest relative increase (+41%). QT-STV also showed the best correlation with indices of left ventricular (LV) hypertrophy, i.e., maximal LV wall thickness normalized for body surface area (BSA; r = 0.461, p = 0.004) or LV mass (determined by cardiac magnetic resonance imaging) normalized for BSA (r = 0.455, p = 0.015). In summary, beat-to-beat QT-STV showed the most marked increase in patients with HCM and may represent a novel marker that merits further testing for increased SCD risk in HCM.
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Affiliation(s)
- Andrea Orosz
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary
| | - Viktória Nagy
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
| | - Henriette Gavallér
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
- Diagnoscan Hungary Ltd., Semmelweis utca 6, 6725 Szeged, Hungary
| | - Miklós Csanády
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
| | - Tamás Forster
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
| | - Julius Gy. Papp
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - Csaba Lengyel
- First Department of Internal Medicine, University of Szeged, Hungary
| | - Róbert Sepp
- Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary
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117
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Frommeyer G, Eckardt L. Drug-induced proarrhythmia: risk factors and electrophysiological mechanisms. Nat Rev Cardiol 2015; 13:36-47. [PMID: 26194552 DOI: 10.1038/nrcardio.2015.110] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Drug-induced ventricular tachyarrhythmias can be caused by cardiovascular drugs, noncardiovascular drugs, and even nonprescription agents. They can result in arrhythmic emergencies and sudden cardiac death. If a new arrhythmia or aggravation of an existing arrhythmia develops during therapy with a drug at a concentration usually considered not to be toxic, the situation can be defined as proarrhythmia. Various cardiovascular and noncardiovascular drugs can increase the occurrence of polymorphic ventricular tachycardia of the 'torsade de pointes' type. Antiarrhythmic drugs, antimicrobial agents, and antipsychotic and antidepressant drugs are the most important groups. Age, female sex, and structural heart disease are important risk factors for the occurrence of torsade de pointes. Genetic predisposition and individual pharmacodynamic and pharmacokinetic sensitivity also have important roles in the generation of arrhythmias. An increase in spatial or temporal dispersion of repolarization and a triangular action-potential configuration have been identified as crucial predictors of proarrhythmia in experimental models. These studies emphasized that sole consideration of the QT interval is not sufficient to assess the proarrhythmic risk. In this Review, we focus on important triggers of proarrhythmia and the underlying electrophysiological mechanisms that can enhance or prevent the development of torsade de pointes.
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Affiliation(s)
- Gerrit Frommeyer
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Albert-Schweitzer Strasse 33, D-48149 Münster, Germany
| | - Lars Eckardt
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Albert-Schweitzer Strasse 33, D-48149 Münster, Germany
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118
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Kistamás K, Hegyi B, Váczi K, Horváth B, Bányász T, Magyar J, Szentandrássy N, Nánási PP. Oxidative shift in tissue redox potential increases beat-to-beat variability of action potential duration. Can J Physiol Pharmacol 2015; 93:563-8. [DOI: 10.1139/cjpp-2014-0531] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Profound changes in tissue redox potential occur in the heart under conditions of oxidative stress frequently associated with cardiac arrhythmias. Since beat-to-beat variability (short term variability, SV) of action potential duration (APD) is a good indicator of arrhythmia incidence, the aim of this work was to study the influence of redox changes on SV in isolated canine ventricular cardiomyocytes using a conventional microelectrode technique. The redox potential was shifted toward a reduced state using a reductive cocktail (containing dithiothreitol, glutathione, and ascorbic acid) while oxidative changes were initiated by superfusion with H2O2. Redox effects were evaluated as changes in “relative SV” determined by comparing SV changes with the concomitant APD changes. Exposure of myocytes to the reductive cocktail decreased SV significantly without any detectable effect on APD. Application of H2O2 increased both SV and APD, but the enhancement of SV was the greater, so relative SV increased. Longer exposure to H2O2 resulted in the development of early afterdepolarizations accompanied by tremendously increased SV. Pretreatment with the reductive cocktail prevented both elevation in relative SV and the development of afterdepolarizations. The results suggest that the increased beat-to-beat variability during an oxidative stress contributes to the generation of cardiac arrhythmias.
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Affiliation(s)
- Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Bence Hegyi
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Krisztina Váczi
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
- Faculty of Pharmacy, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
- Division of Sport Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Norbert Szentandrássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
- Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Péter P. Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
- Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
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119
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Husti Z, Tábori K, Juhász V, Hornyik T, Varró A, Baczkó I. Combined inhibition of key potassium currents has different effects on cardiac repolarization reserve and arrhythmia susceptibility in dogs and rabbits. Can J Physiol Pharmacol 2015; 93:535-44. [DOI: 10.1139/cjpp-2014-0514] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A reliable assessment of the pro-arrhythmic potential for drugs in the development phase remains elusive. Rabbits and dogs are commonly used to create models of pro-arrhythmia, but the differences between them with respect to repolarizing potassium currents are poorly understood. We investigated the incidence of drug-induced torsades de pointes (TdP) and measured conventional ECG parameters and the short-term variability of the QT interval (STVQT) following combined pharmacological inhibition of IK1+IKs and IK1+IKr in conscious dogs and anesthetized rabbits. A high incidence of TdP was observed following the combined inhibition of IK1+IKs in dogs (67% vs. 14% in rabbits). Rabbits exhibited higher TdP incidence after inhibition of IK1+IKr (72% vs. 14% in dogs). Increased TdP incidence was associated with significantly larger STVQT in both models. The relatively different roles of IK1 and IKs in dog and rabbit repolarization reserve should be taken into account when extrapolating the results from animal models of pro-arrhythmia to humans. A stronger repolarization reserve in dogs (likely due to stronger IK1 and IKs), and the more human-like susceptibility to arrhythmia of rabbits argues for the preferred use of rabbits in the evaluation of adverse pro-arrhythmic effects.
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Affiliation(s)
- Zoltán Husti
- Department of Pharmacology and Pharmacotherapy, University of Szeged; H-6720, Dóm tér 12, P.O. Box 427, Szeged, Hungary
| | - Katalin Tábori
- Department of Pharmacology and Pharmacotherapy, University of Szeged; H-6720, Dóm tér 12, P.O. Box 427, Szeged, Hungary
| | - Viktor Juhász
- Department of Pharmacology and Pharmacotherapy, University of Szeged; H-6720, Dóm tér 12, P.O. Box 427, Szeged, Hungary
| | - Tibor Hornyik
- Department of Pharmacology and Pharmacotherapy, University of Szeged; H-6720, Dóm tér 12, P.O. Box 427, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged; H-6720, Dóm tér 12, P.O. Box 427, Szeged, Hungary
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, H-6720, Dóm tér 12, P.O. Box 427, Szeged, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, University of Szeged; H-6720, Dóm tér 12, P.O. Box 427, Szeged, Hungary
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Assessment of efficacy of proarrhythmia biomarkers in isolated rabbit hearts with attenuated repolarization reserve. J Cardiovasc Pharmacol 2015; 64:266-76. [PMID: 24887684 DOI: 10.1097/fjc.0000000000000116] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Isolated hearts with reduced repolarization reserve would be suitable for assessing the proarrhythmic liability of drugs. However, it is not known which proarrhythmia biomarkers indicate the increased susceptibility to torsades de pointes arrhythmia (TdP) in such experimental setting. Thus, we estimated the efficacy of proarrhythmia biomarkers in isolated hearts with attenuated repolarization reserve. Langendorff-perfused rabbit hearts were used. Repolarization reserve was reduced by concomitant inhibition of the rapid (IKr) and slow (IKs) delayed rectifier potassium currents by dofetilide and HMR-1556, respectively. Rate corrected QT (QTc) interval and beat-to-beat variability of the QT interval measured in sinus rhythm or irrespective of rhythm even during arrhythmias (sinus and absolute QT variability, respectively) were tested. QTc failed to predict increased proarrhythmic risk. Sinus QT variability indicated proarrhythmic liability when low concentration of dofetilide was used. However, when arrhythmias compromised sinus variability measurement during coperfusion of catecholamines and elevated concentration of dofetilide, only absolute QT variability indicated increased proarrhythmic risk. Absolute QT variability parameters seem to be the most practical and sensitive biomarkers of proarrhythmic liability in rabbit hearts with reduced repolarization reserve. Absolute QT variability parameters could serve as surrogates for torsades de pointes in drug-safety investigations in isolated rabbit hearts with attenuated repolarization reserve.
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121
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Orosz A, Csajbók É, Czékus C, Gavallér H, Magony S, Valkusz Z, Várkonyi TT, Nemes A, Baczkó I, Forster T, Wittmann T, Papp JG, Varró A, Lengyel C. Increased Short-Term Beat-To-Beat Variability of QT Interval in Patients with Acromegaly. PLoS One 2015; 10:e0125639. [PMID: 25915951 PMCID: PMC4411033 DOI: 10.1371/journal.pone.0125639] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 03/24/2015] [Indexed: 12/23/2022] Open
Abstract
Cardiovascular diseases, including ventricular arrhythmias are responsible for increased mortality in patients with acromegaly. Acromegaly may cause repolarization abnormalities such as QT prolongation and impairment of repolarization reserve enhancing liability to arrhythmia. The aim of this study was to determine the short-term beat-to-beat QT variability in patients with acromegaly. Thirty acromegalic patients (23 women and 7 men, mean age±SD: 55.7±10.4 years) were compared with age- and sex-matched volunteers (mean age 51.3±7.6 years). Cardiac repolarization parameters including frequency corrected QT interval, PQ and QRS intervals, duration of terminal part of T waves (Tpeak-Tend) and short-term variability of QT interval were evaluated. All acromegalic patients and controls underwent transthoracic echocardiographic examination. Autonomic function was assessed by means of five standard cardiovascular reflex tests. Comparison of the two groups revealed no significant differences in the conventional ECG parameters of repolarization (QT: 401.1±30.6 ms vs 389.3±16.5 ms, corrected QT interval: 430.1±18.6 ms vs 425.6±17.3 ms, QT dispersion: 38.2±13.2 ms vs 36.6±10.2 ms; acromegaly vs control, respectively). However, short-term beat-to-beat QT variability was significantly increased in acromegalic patients (4.23±1.03 ms vs 3.02±0.80, P<0.0001). There were significant differences between the two groups in the echocardiographic dimensions (left ventricular end diastolic diameter: 52.6±5.4 mm vs 48.0±3.9 mm, left ventricular end systolic diameter: 32.3±5.2 mm vs 29.1±4.4 mm, interventricular septum: 11.1±2.2 mm vs 8.8±0.7 mm, posterior wall of left ventricle: 10.8±1.4 mm vs 8.9±0.7 mm, P<0.05, respectively). Short-term beat-to-beat QT variability was elevated in patients with acromegaly in spite of unchanged conventional parameters of ventricular repolarization. This enhanced temporal QT variability may be an early indicator of increased liability to arrhythmia.
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Affiliation(s)
- Andrea Orosz
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Éva Csajbók
- 1st Department of Internal Medicine, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Csilla Czékus
- 1st Department of Internal Medicine, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Henriette Gavallér
- 2nd Department of Internal Medicine and Cardiology Center, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Sándor Magony
- 1st Department of Internal Medicine, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Zsuzsanna Valkusz
- 1st Department of Internal Medicine, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Tamás T. Várkonyi
- 1st Department of Internal Medicine, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Attila Nemes
- 2nd Department of Internal Medicine and Cardiology Center, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Tamás Forster
- 2nd Department of Internal Medicine and Cardiology Center, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Tibor Wittmann
- 1st Department of Internal Medicine, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Julius Gy. Papp
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - Csaba Lengyel
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
- 1st Department of Internal Medicine, Faculty of Medicine, University of Szeged, Szeged, Hungary
- * E-mail:
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122
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Champeroux P, Thireau J, Judé S, Laigot-Barbé C, Maurin A, Sola ML, Fowler JSL, Richard S, Le Guennec JY. Short-term variability in QT interval and ventricular arrhythmias induced by dofetilide are dependent on high-frequency autonomic oscillations. Br J Pharmacol 2015; 172:2878-91. [PMID: 25625756 PMCID: PMC4439882 DOI: 10.1111/bph.13093] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 01/15/2015] [Accepted: 01/20/2015] [Indexed: 01/13/2023] Open
Abstract
Background and Purpose The present study was undertaken to investigate an effect of dofetilide, a potent arrhythmic blocker of the voltage-gated K+ channel, hERG, on cardiac autonomic control. Combined with effects on ardiomyocytes, these properties could influence its arrhythmic potency. Experimental Approach The short-term variability of beat-to-beat QT interval (STVQT), induced by dofetilide is a strong surrogate of Torsades de pointes liability. Involvement of autonomic modulation in STVQT was investigated in healthy cynomolgus monkeys and beagle dogs by power spectral analysis under conditions of autonomic blockade with hexamethonium. Key Results Increase in STVQT induced by dofetilide in monkeys and dogs was closely associated with an enhancement of endogenous heart rate and QT interval high-frequency (HF) oscillations. These effects were fully suppressed under conditions of autonomic blockade with hexamethonium. Ventricular arrhythmias, including Torsades de pointes in monkeys, were prevented in both species when HF oscillations were suppressed by autonomic blockade. Similar enhancements of heart rate HF oscillations were found in dogs with other hERG blockers described as causing Torsades de pointes in humans. Conclusions and Implications These results demonstrate for the first time that beat-to-beat ventricular repolarization variability and ventricular arrhythmias induced by dofetilide are dependent on endogenous HF autonomic oscillations in heart rate. When combined with evidence of hERG-blocking properties, enhancement of endogenous HF oscillations in heart rate could constitute an earlier and more sensitive biomarker than STVQT for Torsades de pointes liability, applicable to preclinical regulatory studies conducted in healthy animals.
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Affiliation(s)
- P Champeroux
- Centre de Recherches Biologiques, CERB, Baugy, France
| | - J Thireau
- Centre de Recherches Biologiques, CERB, Baugy, France
| | - S Judé
- Centre de Recherches Biologiques, CERB, Baugy, France
| | | | - A Maurin
- Centre de Recherches Biologiques, CERB, Baugy, France
| | - M L Sola
- Centre de Recherches Biologiques, CERB, Baugy, France
| | - J S L Fowler
- Centre de Recherches Biologiques, CERB, Baugy, France
| | - S Richard
- Centre de Recherches Biologiques, CERB, Baugy, France
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123
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Arrhythmogenesis in a catecholaminergic polymorphic ventricular tachycardia mutation that depresses ryanodine receptor function. Proc Natl Acad Sci U S A 2015; 112:E1669-77. [PMID: 25775566 DOI: 10.1073/pnas.1419795112] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Current mechanisms of arrhythmogenesis in catecholaminergic polymorphic ventricular tachycardia (CPVT) require spontaneous Ca(2+) release via cardiac ryanodine receptor (RyR2) channels affected by gain-of-function mutations. Hence, hyperactive RyR2 channels eager to release Ca(2+) on their own appear as essential components of this arrhythmogenic scheme. This mechanism, therefore, appears inadequate to explain lethal arrhythmias in patients harboring RyR2 channels destabilized by loss-of-function mutations. We aimed to elucidate arrhythmia mechanisms in a RyR2-linked CPVT mutation (RyR2-A4860G) that depresses channel activity. Recombinant RyR2-A4860G protein was expressed equally as wild type (WT) RyR2, but channel activity was dramatically inhibited, as inferred by [(3)H]ryanodine binding and single channel recordings. Mice heterozygous for the RyR2-A4860G mutation (RyR2-A4860G(+/-)) exhibited basal bradycardia but no cardiac structural alterations; in contrast, no homozygotes were detected at birth, suggesting a lethal phenotype. Sympathetic stimulation elicited malignant arrhythmias in RyR2-A4860G(+/-) hearts, recapitulating the phenotype originally described in a human patient with the same mutation. In isoproterenol-stimulated ventricular myocytes, the RyR2-A4860G mutation decreased the peak of Ca(2+) release during systole, gradually overloading the sarcoplasmic reticulum with Ca(2+). The resultant Ca(2+) overload then randomly caused bursts of prolonged Ca(2+) release, activating electrogenic Na(+)-Ca(2+) exchanger activity and triggering early afterdepolarizations. The RyR2-A4860G mutation reveals novel pathways by which RyR2 channels engage sarcolemmal currents to produce life-threatening arrhythmias.
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124
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Long VP, Bonilla IM, Vargas-Pinto P, Nishijima Y, Sridhar A, Li C, Mowrey K, Wright P, Velayutham M, Kumar S, Lee NY, Zweier JL, Mohler PJ, Györke S, Carnes CA. Heart failure duration progressively modulates the arrhythmia substrate through structural and electrical remodeling. Life Sci 2015; 123:61-71. [PMID: 25596015 PMCID: PMC4763601 DOI: 10.1016/j.lfs.2014.12.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 12/15/2014] [Accepted: 12/19/2014] [Indexed: 01/10/2023]
Abstract
AIMS Ventricular arrhythmias are a common cause of death in patients with heart failure (HF). Structural and electrical abnormalities in the heart provide a substrate for such arrhythmias. Canine tachypacing-induced HF models of 4-6 weeks duration are often used to study pathophysiology and therapies for HF. We hypothesized that a chronic canine model of HF would result in greater electrical and structural remodeling than a short term model, leading to a more arrhythmogenic substrate. MAIN METHODS HF was induced by ventricular tachypacing for one (short-term) or four (chronic) months to study remodeling. KEY FINDINGS Left ventricular contractility was progressively reduced, while ventricular hypertrophy and interstitial fibrosis were evident at 4 month but not 1 month of HF. Left ventricular myocyte action potentials were prolonged after 4 (p<0.05) but not 1 month of HF. Repolarization instability and early afterdepolarizations were evident only after 4 months of HF (p<0.05), coinciding with a prolonged QTc interval (p<0.05). The transient outward potassium current was reduced in both HF groups (p<0.05). The outward component of the inward rectifier potassium current was reduced only in the 4 month HF group (p<0.05). The delayed rectifier potassium currents were reduced in 4 (p<0.05) but not 1 month of HF. Reactive oxygen species were increased at both 1 and 4 months of HF (p<0.05). SIGNIFICANCE Reduced Ito, outward IK1, IKs, and IKr in HF contribute to EAD formation. Chronic, but not short term canine HF, results in the altered electrophysiology and repolarization instability characteristic of end-stage human HF.
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Affiliation(s)
- Victor P Long
- College of Pharmacy, The Ohio State University, Columbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Ingrid M Bonilla
- College of Pharmacy, The Ohio State University, Columbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Pedro Vargas-Pinto
- College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | | | - Arun Sridhar
- College of Pharmacy, The Ohio State University, Columbus, OH, USA
| | - Chun Li
- College of Pharmacy, The Ohio State University, Columbus, OH, USA
| | | | - Patrick Wright
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Murugesan Velayutham
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Sanjay Kumar
- College of Pharmacy, The Ohio State University, Columbus, OH, USA
| | - Nam Y Lee
- College of Pharmacy, The Ohio State University, Columbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Jay L Zweier
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Peter J Mohler
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Sandor Györke
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Cynthia A Carnes
- College of Pharmacy, The Ohio State University, Columbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA.
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125
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Assessment of anti-arrhythmic activity of antipsychotic drugs in an animal model: Influence of non-cardiac α1-adrenergic receptors. Eur J Pharmacol 2015; 748:10-7. [DOI: 10.1016/j.ejphar.2014.12.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 11/28/2014] [Accepted: 12/10/2014] [Indexed: 01/09/2023]
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126
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Rodriguez B. In Silico Organ Modelling in Predicting Efficacy and Safety of New Medicines. HUMAN-BASED SYSTEMS FOR TRANSLATIONAL RESEARCH 2014. [DOI: 10.1039/9781782620136-00219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The development of new medicines faces important challenges due to difficulties in the assessment of their efficacy and their safety in the targeted human population. In silico approaches through the use of mathematical modelling and computer simulations are increasingly being used to overcome some of the limitations of current experimental methods used in the development of new medicines. This chapter describes state-of-the-art in silico approaches for the evaluation of the safety and efficacy of medicines targeting important causes of mortality such as cardiovascular disease. Firstly, we describe the in silico multi-scale mathematical models and simulation techniques required to describe drug-induced effects on physiological systems such as the heart from the subcellular to the whole organ level. Then we illustrate the power of in silico approaches used to augment experimental and clinical investigations, by providing the framework to unravel multi-scale mechanisms underlying variability in the response to medicines and to focus on effects in human rather than animal models. We devote the last part of the chapter to discussing the process of validation of in silico models and simulations, which is key in building up their credibility.
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Affiliation(s)
- Blanca Rodriguez
- Department of Computer Science, University of Oxford Parks Road Oxford OX1 3QD UK
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127
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Watanabe Y, Nakamura Y, Cao X, Ohara H, Yamazaki Y, Murayama N, Sugiyama Y, Izumi-Nakaseko H, Ando K, Yamazaki H, Sugiyama A. Intravenous Administration of Apomorphine Does NOT Induce Long QT Syndrome: Experimental Evidence from In Vivo Canine Models. Basic Clin Pharmacol Toxicol 2014; 116:468-75. [PMID: 25370785 DOI: 10.1111/bcpt.12343] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 10/20/2014] [Indexed: 11/29/2022]
Abstract
Apomorphine is a non-selective dopamine D1/D2 receptor agonist, which has been used for patients with Parkinson's disease and reported to induce QT interval prolongation and cardiac arrest. To clarify their causal link, we assessed the cardiovascular and pharmacokinetic profile of apomorphine with the halothane-anaesthetized canine model (n = 4), whereas pro-arrhythmic potential of apomorphine was analysed with the chronic atrioventricular block canine model (n = 4). In the halothane-anaesthetized model, 0.01 mg/kg, i.v. of apomorphine hydrochloride over 10 min., providing about 10 times of its therapeutic concentration, increased the heart rate and ventricular contraction; 0.1 mg/kg over 10 min., providing about 100 times of the therapeutic, prolonged the ventricular effective refractory period; and 1 mg/kg over 10 min., providing about 1000 times of the therapeutic, decreased the ventricular contraction, mean blood pressure and cardiac output together with the intraventricular conduction delay and prolongation of the effective refractory period, whereas the left ventricular end-diastolic pressure, atrioventricular nodal conduction or ventricular repolarization were hardly affected. Meanwhile, in the atrioventricular block model, 1 mg/kg, i.v. of apomorphine hydrochloride over 10 min. neither prolonged the QT interval nor induced torsade de pointes. These results suggest that apomorphine may possess a wide margin of cardiovascular safety contrary to our expectations.
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Affiliation(s)
- Yudai Watanabe
- Department of Pharmacology, Faculty of Medicine, Toho University, Ota-ku, Tokyo, Japan
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128
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Sarusi A, Rárosi F, Szűcs M, Csík N, Farkas AS, Papp JG, Varró A, Forster T, Curtis MJ, Farkas A. Absolute beat-to-beat variability and instability parameters of ECG intervals: biomarkers for predicting ischaemia-induced ventricular fibrillation. Br J Pharmacol 2014; 171:1772-82. [PMID: 24417376 DOI: 10.1111/bph.12579] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/15/2013] [Accepted: 01/03/2014] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND AND PURPOSE Predicting lethal arrhythmia liability from beat-to-beat variability and instability (BVI) of the ECG intervals is a useful technique in drug assessment. Most investigators use only arrhythmia-free ECGs for this. Recently, it was shown that drug-induced torsades de pointes (TdP) liability can be predicted more accurately from BVI measured irrespective of rhythm, even during arrhythmias (absolute BVI). The present study tested the broader applicability of this assessment by examining whether absolute BVI parameters predict another potential lethal arrhythmia, ischaemia-induced ventricular fibrillation (VF). EXPERIMENTAL APPROACH Langendorff-perfused rat hearts were subjected to regional ischaemia for 15 min. Absolute BVI parameters were derived from ECG intervals measured in 40 consecutive ventricular complexes (irrespective of rhythm) immediately preceding VF onset and compared with time-matched values in hearts not expressing VF. KEY RESULTS Increased frequency of non-sinus beats and 'R on T' arrhythmic beats, shortened mean RR and electrical diastolic intervals, and increased BVI of cycle length and repolarization predicted VF occurrence. Absolute BVI parameters that quantify variability of repolarization (e.g. 'short-term variability' of QT interval) had the best predictive power with high sensitivity and specificity. In contrast, VF was not predicted by any BVI parameter derived from the last arrhythmia-free interlude before VF. CONCLUSIONS AND IMPLICATIONS The novel absolute BVI parameters that predicted TdP in rabbit also predict ischaemia-induced VF in rat, indicating a diagnostic and mechanistic congruence. Repolarization inhomogeneity represents a pivotal biomarker of ischaemia-induced VF. The newly validated biomarkers could serve as surrogates for VF in pre-clinical drug investigations.
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Affiliation(s)
- Annamária Sarusi
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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129
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Walmsley J, Mirams GR, Pitt-Francis J, Rodriguez B, Burrage K. Application of stochastic phenomenological modelling to cell-to-cell and beat-to-beat electrophysiological variability in cardiac tissue. J Theor Biol 2014; 365:325-36. [PMID: 25451525 PMCID: PMC4271765 DOI: 10.1016/j.jtbi.2014.10.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 10/21/2014] [Accepted: 10/23/2014] [Indexed: 01/08/2023]
Abstract
Variability in the action potential of isolated myocytes and tissue samples is observed in experimental studies. Variability is manifested as both differences in the action potential (AP) morphology between cells (extrinsic variability), and also ‘intrinsic’ or beat-to-beat variability of repolarization (BVR) in the AP duration of each cell. We studied the relative contributions of experimentally recorded intrinsic and extrinsic variability to dispersion of repolarization in tissue. We developed four cell-specific parameterizations of a phenomenological stochastic differential equation AP model exhibiting intrinsic variability using APs recorded from isolated guinea pig ventricular myocytes exhibiting BVR. We performed simulations in tissue using the four different model parameterizations in the presence and the absence of both intrinsic and extrinsic variability. We altered the coupling of the tissue to determine how inter-cellular coupling affected the dispersion of the AP duration in tissue. Both intrinsic and extrinsic variability were gradually revealed by reduction of tissue coupling. However, the recorded extrinsic variability between individual myocytes produced a greater degree of dispersion in repolarization in tissue than the intrinsic variability of each myocyte. We modelled inter-cell and beat-to-beat repolarization variability in cardiomyocytes. We coupled the cells together into cardiac tissue. Reducing tissue coupling increased repolarization dispersion in tissue. Inter-cell variability had a greater effect on repolarization dispersion.
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Affiliation(s)
- John Walmsley
- Department of Computer Science, University of Oxford, Oxford, United Kingdom.
| | - Gary R Mirams
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Joe Pitt-Francis
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Kevin Burrage
- Department of Computer Science, University of Oxford, Oxford, United Kingdom; School of Mathematical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
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Frommeyer G, Schulze Grotthoff J, Fischer C, Bogossian H, Reinke F, Kochhäuser S, Dechering DG, Fehr M, Milberg P, Eckardt L. Vernakalant in an Experimental Model of Pacing-Induced Heart Failure: Lack of Proarrhythmia Despite Prolongation of Repolarization. J Card Fail 2014; 20:786-792. [DOI: 10.1016/j.cardfail.2014.07.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 06/27/2014] [Accepted: 07/23/2014] [Indexed: 01/10/2023]
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131
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VARKEVISSER ROSANNE, VOS MARCA, BEEKMAN JETD, TIELAND RALPHG, VAN DER HEYDEN MARCELA. AV-Block and Conduction Slowing Prevail Over TdP Arrhythmias in the Methoxamine-Sensitized Pro-Arrhythmic Rabbit Model. J Cardiovasc Electrophysiol 2014; 26:82-9. [DOI: 10.1111/jce.12533] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 08/14/2014] [Accepted: 08/19/2014] [Indexed: 11/27/2022]
Affiliation(s)
- ROSANNE VARKEVISSER
- Department of Medical Physiology; Division Heart & Lungs University Medical Center Utrecht; Utrecht The Netherlands
| | - MARC A. VOS
- Department of Medical Physiology; Division Heart & Lungs University Medical Center Utrecht; Utrecht The Netherlands
| | - JET D. BEEKMAN
- Department of Medical Physiology; Division Heart & Lungs University Medical Center Utrecht; Utrecht The Netherlands
| | - RALPH G. TIELAND
- Department of Medical Physiology; Division Heart & Lungs University Medical Center Utrecht; Utrecht The Netherlands
| | - MARCEL A. VAN DER HEYDEN
- Department of Medical Physiology; Division Heart & Lungs University Medical Center Utrecht; Utrecht The Netherlands
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Niemeijer MN, van den Berg ME, Eijgelsheim M, van Herpen G, Stricker BH, Kors JA, Rijnbeek PR. Short-term QT variability markers for the prediction of ventricular arrhythmias and sudden cardiac death: a systematic review. Heart 2014; 100:1831-6. [PMID: 25092875 DOI: 10.1136/heartjnl-2014-305671] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Sudden cardiac death (SCD) is a major health burden and is primarily caused by ventricular arrhythmias. Currently, the most well-known marker for the risk of ventricular arrhythmias is QT/QTc prolongation. Animal studies indicate that QT variability might be a better indicator. Our objective was to give an overview of the literature on QT variability in humans, therefore we performed a free-text search in PubMed and Embase from inception through February 2013. We identified nine QT variability markers in 109 studies reporting on QT variability markers, measured on the surface ECG. QT variability can be distinguished using two characteristics: heart rate normalisation and whether QT interval is measured on consecutive beats. Most study populations were small (median 48 subjects, range 1-805) and different methods, time intervals and leads for measurement were used. QT variability markers were determinants for the risk of ventricular arrhythmias, (sudden) cardiac death and total mortality. Few studies compared the predictive value of QT variability with that of QT/QTc prolongation. A study comparing all different QT variability markers is lacking. In conclusion, QT variability markers are potential determinants of ventricular arrhythmias and cardiac mortality. However, it is unclear which marker and methodology are clinically most useful as well as what reference values are reliable. More studies on larger datasets are needed to find the most accurate marker for the prediction of arrhythmias and SCD to assess its value in addition to QT/QTc duration and its role in drug-induced arrhythmia and sudden death.
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Affiliation(s)
- Maartje N Niemeijer
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Marten E van den Berg
- Department of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Mark Eijgelsheim
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Gerard van Herpen
- Department of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Bruno H Stricker
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands Inspectorate of Health Care, The Hague, The Netherlands
| | - Jan A Kors
- Department of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Peter R Rijnbeek
- Department of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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133
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Contribution of ion currents to beat-to-beat variability of action potential duration in canine ventricular myocytes. Pflugers Arch 2014; 467:1431-1443. [DOI: 10.1007/s00424-014-1581-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/11/2014] [Accepted: 07/14/2014] [Indexed: 12/19/2022]
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134
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Tereshchenko LG, Berger RD. Towards a better understanding of QT interval variability. Ther Adv Drug Saf 2014; 2:245-51. [PMID: 25083216 DOI: 10.1177/2042098611421209] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) Guideline E14 recommends 'Thorough QT Study' as a standard assessment of drug-induced QT interval prolongation. At the same time, the value of drug-induced QTc prolongation as a surrogate marker for risk of life-threatening polymorphic ventricular tachycardia known as torsades des pointes remains controversial. Beat-to-beat variability of QT interval was recently proposed as an alternative metric. The following review addresses mechanisms of beat-to-beat QT variability, methods of QT interval variability measurements, and its prognostic value in clinical studies.
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Affiliation(s)
- Larisa G Tereshchenko
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ronald D Berger
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Carnegie 592, 600 N. Wolfe St., Baltimore, MD 21287, USA
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135
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Postema PG, Wilde AAM. The measurement of the QT interval. Curr Cardiol Rev 2014; 10:287-94. [PMID: 24827793 PMCID: PMC4040880 DOI: 10.2174/1573403x10666140514103612] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 06/10/2013] [Accepted: 01/28/2014] [Indexed: 12/14/2022] Open
Abstract
The evaluation of every electrocardiogram should also include an effort to interpret the QT interval to assess the risk of malignant arrhythmias and sudden death associated with an aberrant QT interval. The QT interval is measured from the beginning of the QRS complex to the end of the T-wave, and should be corrected for heart rate to enable comparison with reference values. However, the correct determination of the QT interval, and its value, appears to be a daunting task. Although computerized analysis and interpretation of the QT interval are widely available, these might well over- or underestimate the QT interval and may thus either result in unnecessary treatment or preclude appropriate measures to be taken. This is particularly evident with difficult T-wave morphologies and technically suboptimal ECGs. Similarly, also accurate manual assessment of the QT interval appears to be difficult for many physicians worldwide. In this review we delineate the history of the measurement of the QT interval, its underlying pathophysiological mechanisms and the current standards of the measurement of the QT interval, we provide a glimpse into the future and we discuss several issues troubling accurate measurement of the QT interval. These issues include the lead choice, U-waves, determination of the end of the T-wave, different heart rate correction formulas, arrhythmias and the definition of normal and aberrant QT intervals. Furthermore, we provide recommendations that may serve as guidance to address these complexities and which support accurate assessment of the QT interval and its interpretation.
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Affiliation(s)
| | - Arthur A M Wilde
- Department of Cardiology, Academic Medical Center, P.O. box 22660, 1100 DD Amsterdam, The Netherlands.
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136
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Sauer AJ, Kaplan R, Xue J, Dorsey P, Hayes M, Shah SJ, Passman R. Electrocardiographic markers of repolarization heterogeneity during dofetilide or sotalol initiation for paroxysmal atrial fibrillation. Am J Cardiol 2014; 113:2030-5. [PMID: 24793679 DOI: 10.1016/j.amjcard.2014.03.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/06/2014] [Accepted: 03/06/2014] [Indexed: 10/25/2022]
Abstract
Serial electrocardiographic monitoring of ΔQTc as an assumed harbinger of proarrhythmia is currently recommended for dofetilide and sotalol initiation. Markers of repolarization heterogeneity such as increased peak to end of T-wave (TpTe) duration and abnormal T-wave morphology may also predict proarrhythmia. We investigated whether such T-wave measurements on baseline electrocardiogram will correlate with ΔQTc after drug initiation. An analysis of 140 consecutive patients with paroxysmal atrial fibrillation hospitalized in sinus rhythm for sotalol or dofetilide initiation was performed. Baseline and serial electrocardiograms were analyzed using QT Guard Plus software (GE Healthcare), which measured QTc and TpTe and scored T-wave morphology for asymmetry, notching, and flatness using T-wave vector magnitude and principal component analysis algorithms. Sotalol and dofetilide were administered in 71% and 29% of patients, respectively. Mean age was 61 ± 14 years, and 34% were women. After a single dose of either drug, there was a statistically significant increase in QTc and TpTe (p <0.01), as well as composite and individual T-wave markers of repolarization heterogeneity (p <0.01). QTc increased by a mean of 19 ± 30 ms after initial antiarrhythmic dose. ΔQTc was inversely related to baseline QTc and TpTe (p <0.01). After controlling for baseline QTc, there was no independent association between T-wave markers of repolarization heterogeneity and ΔQTc. In conclusion, for patients with paroxysmal atrial fibrillation admitted for dofetilide or sotalol loading, T-wave markers of increased repolarization heterogeneity are measurable within hours after initiation. A shorter baseline QTc is associated with an increased ΔQTc; however, there is no independent relation between baseline T-wave markers of repolarization heterogeneity and ΔQTc.
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137
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Feeny A, Han L, Tereshchenko LG. Repolarization lability measured on 10-second ECG by spatial TT' angle: reproducibility and agreement with QT variability. J Electrocardiol 2014; 47:708-15. [PMID: 25012076 DOI: 10.1016/j.jelectrocard.2014.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Reproducibility of spatial TT' angle on the 10-second ECG and its agreement with QT variability has not been previously studied. METHODS We analyzed 2 randomly selected 10-second segments within 3-minute resting orthogonal ECG in 172 healthy IDEAL study participants (age 38.1±15.2years, 50% male, 94% white). Repolarization lability was measured by the QT variance (QTV), short-term QT variability (STV(QT)), and spatial TT' angle. Bland-Altman analysis was used to assess the agreement between different log-transformed metrics of repolarization lability, and to assess the reproducibility. RESULTS The heart rate showed a very high reproducibility (bias 0.14%, Lin's rho_c=0.99). As expected, noise suppression by averaging improves reproducibility. Agreement between two 10-second LogQTV was poor (bias -0.04; 95% limits of agreement [-1.89; 1.81]), while LogSTV(QT) (0.04 [-1.01; 1.10]), and especially LogTT' angle (-0.009 [-0.84; 0.82]) was better. CONCLUSION TT' angle is a satisfactory reproducible metric of repolarization lability on the 10-second ECG.
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Affiliation(s)
- Albert Feeny
- Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Lichy Han
- Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Larisa G Tereshchenko
- The Division of Cardiology, Department of Medicine, Johns Hopkins Hospital, Baltimore, MD, USA; The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.
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138
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SHI SHAOBO, LIU TAO, LI YAFENG, QIN MU, TANG YANHONG, SHEN JERRYY, LIANG JINJUN, YANG BO, HUANG CONGXIN. Chronic N-Methyl-d-Aspartate Receptor Activation Induces Cardiac Electrical Remodeling and Increases Susceptibility to Ventricular Arrhythmias. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2014; 37:1367-77. [PMID: 24888504 DOI: 10.1111/pace.12430] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 04/17/2014] [Accepted: 04/23/2014] [Indexed: 11/26/2022]
Affiliation(s)
- SHAOBO SHI
- Department of Cardiology; Renmin Hospital of Wuhan University; Wuhan PR China
- Cardiovascular Research Institute; Wuhan University; Wuhan PR China
| | - TAO LIU
- Department of Cardiology; Renmin Hospital of Wuhan University; Wuhan PR China
- Cardiovascular Research Institute; Wuhan University; Wuhan PR China
| | - YAFENG LI
- Department of Cardiology; Renmin Hospital of Wuhan University; Wuhan PR China
- Cardiovascular Research Institute; Wuhan University; Wuhan PR China
| | - MU QIN
- The First Clinical Medical College of Three Gorges University; Yichang PR China
| | - YANHONG TANG
- Cardiovascular Research Institute; Wuhan University; Wuhan PR China
| | - JERRY Y. SHEN
- Department of Family Medicine; College of Community Health Sciences; University of Alabama; Tuscaloosa Alabama
| | - JINJUN LIANG
- Department of Cardiology; Renmin Hospital of Wuhan University; Wuhan PR China
| | - BO YANG
- Department of Cardiology; Renmin Hospital of Wuhan University; Wuhan PR China
| | - CONGXIN HUANG
- Department of Cardiology; Renmin Hospital of Wuhan University; Wuhan PR China
- Cardiovascular Research Institute; Wuhan University; Wuhan PR China
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139
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On-chip in vitro cell-network pre-clinical cardiac toxicity using spatiotemporal human cardiomyocyte measurement on a chip. Sci Rep 2014; 4:4670. [PMID: 24751527 PMCID: PMC5381194 DOI: 10.1038/srep04670] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 03/24/2014] [Indexed: 11/09/2022] Open
Abstract
To overcome the limitations and misjudgments of conventional prediction of arrhythmic cardiotoxicity, we have developed an on-chip in vitro predictive cardiotoxicity assay using cardiomyocytes derived from human stem cells employing a constructive spatiotemporal two step measurement of fluctuation (short-term variability; STV) of cell's repolarization and cell-to-cell conduction time, representing two origins of lethal arrhythmia. Temporal STV of field potential duration (FPD) showed a potential to predict the risks of lethal arrhythmia originated from repolarization dispersion for false negative compounds, which was not correctly predicted by conventional measurements using animal cells, even for non-QT prolonging clinical positive compounds. Spatial STV of conduction time delay also unveiled the proarrhythmic risk of asynchronous propagation in cell networks, whose risk cannot be correctly predicted by single-cell-based measurements, indicating the importance of the spatiotemporal fluctuation viewpoint of in vitro cell networks for precise prediction of lethal arrhythmia reaching clinical assessment such as thorough QT assay.
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140
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Nilsson MF, Webster WS. Effects of Macrolide Antibiotics on Rat Embryonic Heart Function In Vitro. ACTA ACUST UNITED AC 2014; 101:189-98. [DOI: 10.1002/bdrb.21107] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/15/2014] [Accepted: 02/16/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Mats F. Nilsson
- Drug Safety and Toxicology; Department of Pharmaceutical Biosciences; Uppsala University; Uppsala Sweden
| | - William S. Webster
- Drug Safety and Toxicology; Department of Pharmaceutical Biosciences; Uppsala University; Uppsala Sweden
- Department of Anatomy and Histology; School of Medical Sciences; University of Sydney; Sydney Australia
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141
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Frommeyer G, Milberg P, Clauss C, Schmidt M, Ramtin S, Kaese S, Grundmann F, Grotthoff JS, Pott C, Eckardt L. Electrophysiological profile of vernakalant in an experimental whole-heart model: the absence of proarrhythmia despite significant effect on myocardial repolarization. Europace 2014; 16:1240-8. [PMID: 24696223 DOI: 10.1093/europace/euu014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIM The most recent European Society of Cardiology (ESC) update on atrial fibrillation has introduced vernakalant (VER) for pharmacological cardioversion of atrial fibrillation. The aim of the present study was to investigate the safety profile of VER in a sensitive model of proarrhythmia. METHODS AND RESULTS In 36 Langendorff-perfused rabbit hearts, VER (10, 30 µM, n = 12); ranolazine (RAN, 10, 30 µM, n = 12), or sotalol (SOT, 50; 100 µM, n = 12) were infused after obtaining baseline data. Monophasic action potentials and a 12-lead electrocardiogram showed a significant QT prolongation after application of VER as compared with baseline (10 µM: +25 ms, 30 µM: +50 ms, P < 0.05) accompanied by an increase of action potential duration (APD). The increase in APD90 was accompanied by a more marked increase in effective refractory period (ERP) leading to a significant increase in post-repolarization refractoriness (PRR, 10 µM: +30 ms, 30 µM: +36 ms, P < 0.05). Vernakalant did not affect the dispersion of repolarization. Lowered potassium concentration in bradycardic hearts did not provoke early afterdepolarizations (EADs) or polymorphic ventricular tachycardia (pVT). Comparable results were obtained with RAN. Hundred micromolars of SOT led to an increase in QT interval (+49 ms) and APD90 combined with an increased ERP and PRR (+23 ms). In contrast to VER, 100 µM SOT led to a significant increase in dispersion of repolarization and to the occurrence of EAD in 10 of 12 and pVT in 8 of 12 hearts. CONCLUSION In the present study, application of VER and SOT led to a comparable prolongation of myocardial repolarization. Both drugs increased the PRR. However, VER neither affect the dispersion of repolarization nor induce EAD and therefore did not cause proarrhythmia.
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Affiliation(s)
- Gerrit Frommeyer
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
| | - Peter Milberg
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
| | - Catharina Clauss
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
| | - Marco Schmidt
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
| | - Shahram Ramtin
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
| | - Sven Kaese
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
| | - Fabian Grundmann
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
| | - Jochen Schulze Grotthoff
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
| | - Christian Pott
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
| | - Lars Eckardt
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, 48149 Münster, Germany
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142
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Gemmell P, Burrage K, Rodriguez B, Quinn TA. Population of computational rabbit-specific ventricular action potential models for investigating sources of variability in cellular repolarisation. PLoS One 2014; 9:e90112. [PMID: 24587229 PMCID: PMC3938586 DOI: 10.1371/journal.pone.0090112] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 01/29/2014] [Indexed: 11/18/2022] Open
Abstract
Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration) and to identify its potential causes. A systematic exploration of the effects of simultaneously varying the magnitude of six transmembrane current conductances (transient outward, rapid and slow delayed rectifier K+, inward rectifying K+, L-type Ca2+, and Na+/K+ pump currents) in two rabbit-specific ventricular action potential models (Shannon et al. and Mahajan et al.) at multiple cycle lengths (400, 600, 1,000 ms) was performed. This was accomplished with distributed computing software specialised for multi-dimensional parameter sweeps and grid execution. An initial population of 15,625 parameter sets was generated for both models at each cycle length. Action potential durations of these populations were compared to experimentally derived ranges for rabbit ventricular myocytes. 1,352 parameter sets for the Shannon model and 779 parameter sets for the Mahajan model yielded action potential duration within the experimental range, demonstrating that a wide array of ionic conductance values can be used to simulate a physiological rabbit ventricular action potential. Furthermore, by using clutter-based dimension reordering, a technique that allows visualisation of multi-dimensional spaces in two dimensions, the interaction of current conductances and their relative importance to the ventricular action potential at different cycle lengths were revealed. Overall, this work represents an important step towards a better understanding of the role that variability in current conductances may play in experimentally observed intercellular variability of rabbit ventricular action potential repolarisation.
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Affiliation(s)
- Philip Gemmell
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Kevin Burrage
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia
| | - Blanca Rodriguez
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - T. Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
- * E-mail:
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143
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Kazusa K, Nakamura Y, Watanabe Y, Ando K, Sugiyama A. Effects of pH on nifekalant-induced electrophysiological change assessed in the Langendorff heart model of guinea pigs. J Pharmacol Sci 2014; 124:153-9. [PMID: 24451996 DOI: 10.1254/jphs.13127fp] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Since information regarding the effects of pH on the extent of nifekalant-induced repolarization delay and torsades de pointes remains limited, we assessed it with a Langendorff heart model of guinea pigs. First, we investigated the effects of pH change from 7.4 to 6.4 on the bipolar electrogram simulating surface lead II ECG, monophasic action potential (MAP), effective refractory period (ERP), and terminal repolarization period (TRP) and found that acidic condition transiently enhanced the ventricular repolarization. Next, we investigated the effects of pH change from 6.4 to 7.4 in the presence of nifekalant (10 μM) on the ECG, MAP, ERP, TRP, and short-term variability (STV) of MAP90 and found that the normalization of pH prolonged the MAP90 and ERP while the TRP remained unchanged, suggesting the increase in electrical vulnerability of the ventricle. Meanwhile, the STV of MAP90 was the largest at pH 6.4 in the presence of nifekalant, indicating the increase in temporal dispersion of repolarization, which gradually decreased with the return of pH to 7.4.Thus, a recovery period from acidosis might be more dangerous than during the acidosis, because electrical vulnerability may significantly increase for this period while temporal dispersion of repolarization remained increased.
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Affiliation(s)
- Katsuyuki Kazusa
- Department of Pharmacology, Faculty of Medicine, Toho University, Japan
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144
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Yamazaki K, Hihara T, Kato H, Fukushima T, Fukushima K, Taniguchi T, Yoshinaga T, Miyamoto N, Ito M, Sawada K. Beat-to-Beat Variability in Field Potential Duration in Human Embryonic Stem Cell-Derived Cardiomyocyte Clusters for Assessment of Arrhythmogenic Risk, and a Case Study of Its Application. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/pp.2014.51017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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145
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Effects of Endothelin-1 Chronic Stimulation on Electrical Restitution, Beat-to-beat Variability of Repolarization, and Ventricular Arrhythmogenesis. J Cardiovasc Pharmacol 2013; 62:549-58. [DOI: 10.1097/fjc.0000000000000015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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146
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Frommeyer G, Milberg P, Uphaus T, Kaiser D, Kaese S, Breithardt G, Eckardt L. Antiarrhythmic Effect of Ranolazine in Combination with Class III Drugs in an Experimental Whole-Heart Model of Atrial Fibrillation. Cardiovasc Ther 2013; 31:e63-71. [DOI: 10.1111/1755-5922.12035] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Gerrit Frommeyer
- Division of Electrophysiology; Department of Cardiovascular Medicine; University Hospital of Münster; Münster Germany
| | - Peter Milberg
- Division of Electrophysiology; Department of Cardiovascular Medicine; University Hospital of Münster; Münster Germany
| | - Timo Uphaus
- Division of Electrophysiology; Department of Cardiovascular Medicine; University Hospital of Münster; Münster Germany
| | - Dennis Kaiser
- Division of Electrophysiology; Department of Cardiovascular Medicine; University Hospital of Münster; Münster Germany
| | - Sven Kaese
- Division of Electrophysiology; Department of Cardiovascular Medicine; University Hospital of Münster; Münster Germany
| | - Günter Breithardt
- Division of Electrophysiology; Department of Cardiovascular Medicine; University Hospital of Münster; Münster Germany
| | - Lars Eckardt
- Division of Electrophysiology; Department of Cardiovascular Medicine; University Hospital of Münster; Münster Germany
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147
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van Borren MMGJ, Vos MA, Houtman MJC, Antoons G, Ravesloot JH. Increased sarcolemmal Na(+)/H(+) exchange activity in hypertrophied myocytes from dogs with chronic atrioventricular block. Front Physiol 2013; 4:322. [PMID: 24324438 PMCID: PMC3840718 DOI: 10.3389/fphys.2013.00322] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/16/2013] [Indexed: 11/13/2022] Open
Abstract
Dogs with compensated biventricular hypertrophy due to chronic atrioventricular block (cAVB), are more susceptible to develop drug-induced Torsade-de-Pointes arrhythmias and sudden cardiac death. It has been suggested that the increased Na(+) influx in hypertrophied cAVB ventricular myocytes contribute to these lethal arrhythmias. The increased Na(+) influx was not mediated by Na(+) channels, in fact the Na(+) current proved reduced in cAVB myocytes. Here we tested the hypothesis that increased activity of the Na(+)/H(+) exchanger type 1 (NHE-1), commonly observed in hypertrophic hearts, causes the elevated Na(+) influx. Cardiac acid-base transport was studied with a pH-sensitive fluorescent dye in ventricular myocytes isolated from control and hypertrophied cAVB hearts; the H(+) equivalent flux through NHE-1, Na(+)-HCO(-) 3 cotransport (NBC), Cl(-)/OH(-) exchange (CHE), and Cl(-)/HCO(-) 3 exchange (AE) were determined and normalized per liter cell water and corrected for surface-to-volume ratio. In cAVB, sarcolemmal NHE-1 flux was increased by 65 ± 6.3% in the pH i interval 6.3-7.2 and NBC, AE, and CHE fluxes remained unchanged. Accordingly, at steady-state intracellular pH the total sarcolemmal Na(+) influx by NHE-1 + NBC increased from 8.5 ± 1.5 amol/μm(2)/min in normal myocytes to 15 ± 2.4 amol/μm(2)/min in hypertrophied cAVB myocytes. We conclude that compensated cardiac hypertrophy in cAVB dogs is accompanied with an increased sarcolemmal NHE-1 activity. This in conjunction with unchanged activity of the other acid-base transporters will raise the intracellular Na(+) in hypertrophied cAVB myocytes.
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148
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Varkevisser R, van der Heyden MAG, Tieland RG, Beekman JDM, Vos MA. Vernakalant is devoid of proarrhythmic effects in the complete AV block dog model. Eur J Pharmacol 2013; 720:49-54. [PMID: 24211677 DOI: 10.1016/j.ejphar.2013.10.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 10/25/2013] [Accepted: 10/29/2013] [Indexed: 11/28/2022]
Abstract
The anesthetized chronic AV-blocked dog (cAVB) and methoxamine-sensitized rabbit model are widely used to determine pro-arrhythmic properties of drugs. In general, both models show similar results. However, conflicting data have also been reported; K201 and AZD1305 induced Torsade de Pointes (TdP) exclusively in cAVB dogs. Vernakalant, an antiarrhythmic drug that blocks several ion channels has been approved only in Europe. Its propensity to induce repolarization-dependent TdP arrhythmias has been evaluated solely in the methoxamine-sensitized rabbits. We therefore assessed the proarrhythmic potential of vernakalant in the cAVB dog model. Vernakalant was evaluated in 10 mongrel dogs (sinus rhythm (SR) 2mg/kg; chronic AV block (cAVB) 2+3mg/kg). The same dogs were challenged with dofetilide (25 μg/kg) to evaluate TdP inducibility. During the serial experiments the animals were paced from the right ventricular apex (60 beats/min). Short-term variability of repolarization (STV) was quantified for proarrhythmic risk. In SR (n=8) vernakalant prolonged QT (265 ± 11 to 311 ± 18 ms P<0.01(**)) but not PQ or QRS. In cAVB (n=8), 2mg/kg vernakalant prolonged QT (391 ± 43 to 519 ± 73 ms(**)) and QRS (103 ± 24 to 108 ± 23 ms(**)). After a 30 min lag-time, 3mg/kg vernakalant (n=4) increased QT to a lesser extent (413 ± 34 to 454 ± 27 ms(**)) while maintaining QRS prolongation (114 ± 18 to 122 ± 20 ms(**)). Neither dose increased STV or caused arrhythmias. Dofetilide prolonged QT (398 ± 51 to 615 ± 71 ms(**)), increased STV (1.0 ± 0.4 to 2.2 ± 1.0 ms P<0.05(⁎)) and induced TdP arrhythmias in 6/8(⁎) cAVB dogs. Vernakalant did not induce arrhythmias in the cAVB dog model. Higher dosages (3mg/kg) did not prolong repolarization further whereas negative inotropic effects were starting to become apparent precluding further increases in dose.
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Affiliation(s)
- Rosanne Varkevisser
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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149
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Speerschneider T, Grubb S, Metoska A, Olesen SP, Calloe K, Thomsen MB. Development of heart failure is independent of K+ channel-interacting protein 2 expression. J Physiol 2013; 591:5923-37. [PMID: 24099801 DOI: 10.1113/jphysiol.2013.263483] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Abnormal ventricular repolarization in ion channelopathies and heart disease is a major cause of ventricular arrhythmias and sudden cardiac death. K(+) channel-interacting protein 2 (KChIP2) expression is significantly reduced in human heart failure (HF), contributing to a loss of the transient outward K(+) current (Ito). We aim to investigate the possible significance of a changed KChIP2 expression on the development of HF and proarrhythmia. Transverse aortic constrictions (TAC) and sham operations were performed in wild-type (WT) and KChIP2(-/-) mice. Echocardiography was performed before and every 2 weeks after the operation. Ten weeks post-surgery, surface ECG was recorded and we paced the heart in vivo to induce arrhythmias. Afterwards, tissue from the left ventricle was used for immunoblotting. Time courses of HF development were comparable in TAC-operated WT and KChIP2(-/-) mice. Ventricular protein expression of KChIP2 was reduced by 70% after 10 weeks TAC in WT mice. The amplitudes of the J and T waves were enlarged in KChIP2(-/-) control mice. Ventricular effective refractory period, RR, QRS and QT intervals were longer in mice with HF compared to sham-operated mice of either genotype. Pacing-induced ventricular tachycardia (VT) was observed in 5/10 sham-operated WT mice compared with 2/10 HF WT mice with HF. Interestingly, and contrary to previously published data, sham-operated KChIP2(-/-) mice were resistant to pacing-induced VT resulting in only 1/10 inducible mice. KChIP2(-/-) with HF mice had similar low vulnerability to inducible VT (1/9). Our results suggest that although KChIP2 is downregulated in HF, it is not orchestrating the development of HF. Moreover, KChIP2 affects ventricular repolarization and lowers arrhythmia susceptibility. Hence, downregulation of KChIP2 expression in HF may be antiarrhythmic in mice via reduction of the fast transient outward K(+) current.
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Affiliation(s)
- Tobias Speerschneider
- M. B. Thomsen: Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3b Blegdamsvej, building 12.5.36, Copenhagen N, Denmark.
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Chain ASY, Sturkenboom MCJM, Danhof M, Della Pasqua OE. Establishing in vitro to clinical correlations in the evaluation of cardiovascular safety pharmacology. DRUG DISCOVERY TODAY. TECHNOLOGIES 2013; 10:e373-e383. [PMID: 24050134 DOI: 10.1016/j.ddtec.2012.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Preclinical studies are vital in establishing the efficacy and safety of a new chemical entity (NCE) in humans. To deliver meaningful information, experiments have to be well defined and provide outcome that is relevant and translatable to humans. This review briefly surveys the various preclinical experiments that are frequently conducted to assess drug effects on cardiac conductivity in early drug development. We examine the different approaches used to establish correlations between non-clinical and clinical settings and discuss their value in the evaluation of cardiovascular risk.
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