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Guevara A, Smith CER, Wang L, Caldwell JL, Tapa S, Stuart SDF, Ma BW, Ng GA, Habecker BA, Wang Z, Ripplinger CM. Sympathetic structural and electrophysiological remodeling in a rabbit model of reperfused myocardial infarction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.05.597494. [PMID: 38895350 PMCID: PMC11185619 DOI: 10.1101/2024.06.05.597494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Chondroitin sulfate proteoglycans (CSPGs) inhibit sympathetic reinnervation in rodent hearts post myocardial infarction (MI), causing regional hypo-innervation that is associated with supersensitivity of β-adrenergic receptors and increased arrhythmia susceptibility. To investigate the role of CSPGs and hypo-innervation in the heart of larger mammals, we used a rabbit model of reperfused MI and tested electrophysiological responses to sympathetic nerve stimulation (SNS). Innervated hearts from MI and sham rabbits were optically mapped using voltage and Ca 2+ -sensitive dyes. SNS was performed with electrical stimulation of the spinal cord and β-adrenergic responsiveness was tested using isoproterenol. Sympathetic nerve density and CSPG expression were evaluated using immunohistochemistry. CSPGs were robustly expressed in the infarct and border zone of all MI hearts, and the presence of CSPGs was associated with reduced sympathetic nerve density in the infarct vs. remote region. Action potential duration (APD) dispersion and susceptibility to ventricular tachycardia/fibrillation (VT/VF) were increased with SNS in MI hearts but not in sham. SNS decreased APD 80 in MI but not sham hearts, while isoproterenol decreased APD 80 in both groups. Isoproterenol also shortened Ca 2+ transient duration (CaTD 80 ) in both groups but to a greater extent in MI hearts. Our data suggest sympathetic remodeling post-MI is similar between species, with CSPGs associated with sympathetic hypo-innervation. Despite a reduction in sympathetic nerve density, the infarct region of MI hearts remained responsive to both physiological SNS and isoproterenol, potentially through preserved or elevated β-adrenergic responsiveness, which may underly increased APD dispersion and susceptibility for VT/VF. NEW & NOTEWORTHY Here we show that CSPGs are present in the infarcts of rabbit hearts with reperfused MI, where they are associated with reduced sympathetic nerve density. Despite hypo-innervation, sympathetic responsiveness is maintained or enhanced in MI rabbit hearts, which also demonstrate increased APD dispersion and tendency for arrhythmias following sympathetic modulation. Together, this study indicates that the mechanisms of sympathetic remodeling post-MI are similar between species, with hypo-innervation likely associated with enhanced β-adrenergic sensitivity.
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Sokolowski K, Turner PV, Lewis E, Wange RL, Fortin MC. Exploring rabbit as a nonrodent species for general toxicology studies. Toxicol Sci 2024; 199:29-39. [PMID: 38374304 DOI: 10.1093/toxsci/kfae022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024] Open
Abstract
To avoid adverse events in humans, toxicity studies in nonclinical species have been the foundation of safety evaluation in the pharmaceutical industry. However, it is recognized that working with animals in research is a privilege, and conscientious use should always respect the 3Rs: replacement, reduction, and refinement. In the wake of the shortages in routine nonrodent species and considering that nonanimal methods are not yet sufficiently mature, the value of the rabbit as a nonrodent species is worth exploring. Historically used in vaccine, cosmetic, and medical device testing, the rabbit is seldom used today as a second species in pharmaceutical development, except for embryo-fetal development studies, ophthalmic therapeutics, some medical devices and implants, and vaccines. Although several factors affect the decision of species selection, including pharmacological relevance, pharmacokinetics, and ADME considerations, there are no perfect animal models. In this forum article, we bring together experts from veterinary medicine, industry, contract research organizations, and government to explore the pros and cons, residual concerns, and data gaps regarding the use of the rabbit for general toxicity testing.
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Affiliation(s)
- Katie Sokolowski
- Safety Assessment, Development Sciences, Denali Therapeutics Inc, South San Francisco, California 94080, USA
| | - Patricia V Turner
- Global Animal Welfare & Training, Charles River Laboratories, Wilmington, Massachusetts 01887, USA
- Department of Pathobiology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Elise Lewis
- Safety Assessment, Charles River Laboratories, Horsham, Pennsylvania 19044, USA
| | - Ronald L Wange
- Office of New Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland 20993, USA
| | - Marie C Fortin
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, New Jersey 08854, USA
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Eckardt L, Veltmann C. More than 30 years of Brugada syndrome: a critical appraisal of achievements and open issues. Herzschrittmacherther Elektrophysiol 2024; 35:9-18. [PMID: 38085327 DOI: 10.1007/s00399-023-00983-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2023] [Indexed: 02/21/2024]
Abstract
Over the last three decades, what is referred to as Brugada syndrome (BrS) has developed from a clinical observation of initially a few cases of sudden cardiac death (SCD) in the absence of structural heart disease with ECG signs of "atypical right bundle brunch block" to a predominantly electrocardiographic, and to a lesser extent genetic, diagnosis. Today, BrS is diagnosed in patients without overt structural heart disease and a spontaneous Brugada type 1 ECG pattern regardless of symptoms. The diagnosis of BrS is less clear in those with an only transient or drug-induced type 1 Brugada pattern, but should be considered in the presence of an arrhythmic syncope, family history of BrS, or family history of sudden death. In addition to survived cardiac arrest, syncope is probably the single most decisive risk marker for future arrhythmias. For asymptomatic BrS, risk stratification remains challenging. General recommendations to lower the risk in BrS include avoidance of drugs/agents known to induce and/or increase right precordial ST-segment elevation, including treatment of fever with antipyretic drugs. Several ECG markers that have been associated with an increased risk of SCD have been incorporated into a recently published risk score for BrS. The aim of this article is to provide an overview of the status of risk stratification and to illustrate open issues und gaps in evidence in BrS.
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Affiliation(s)
- Lars Eckardt
- Department for Cardiology II: Electrophysiology, University Hospital Münster, Münster, Germany.
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Münster, Germany.
| | - Christian Veltmann
- Heart Center Bremen, Electrophysiology Bremen, Klinikum Links der Weser, Bremen, Germany
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Wolfes J, Uphoff J, Kemena S, Wegner F, Rath B, Eckardt L, Frommeyer G, Ellermann C. Divergent electrophysiologic action of dapagliflozin and empagliflozin on ventricular and atrial tachyarrhythmias in isolated rabbit hearts. Front Cardiovasc Med 2024; 11:1369250. [PMID: 38455723 PMCID: PMC10918010 DOI: 10.3389/fcvm.2024.1369250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 02/12/2024] [Indexed: 03/09/2024] Open
Abstract
Background The use of SGLT-2 inhibitors has revolutionized heart failure therapy. Evidence suggests a reduced incidence of ventricular and atrial arrhythmias in patients with dapagliflozin or empagliflozin treatment. It is unclear to what extent the reduced arrhythmia burden is due to direct effects of the SGLT2 inhibitors or is solely a marker of improved cardiac function. Methods One hundred five rabbit hearts were allocated to eight groups and retrogradely perfused, employing a Langendorff setup. Action potential duration at 90% of repolarization (APD90), QT intervals, effective refractory periods, conduction velocity, and dispersion of repolarization were obtained with monophasic action potential catheters. A model for tachyarrhythmias was established with the IKr blocker erythromycin for QT prolongation associated proarrhythmia as well as the potassium channel opener pinacidil for a short-QT model. An atrial fibrillation (AF) model was created with isoproterenol and acetylcholine. With increasing concentrations of both SGLT2 inhibitors, reductions in QT intervals and APD90 were observed, accompanied by a slight increase in ventricular arrhythmia episodes. During drug-induced proarrhythmia, empagliflozin succeeded in decreasing QT intervals, APD90, and VT burden whereas dapagliflozin demonstrated no significant effects. In the presence of pinacidil induced arrhythmogenicity, neither SGLT2 inhibitor had a significant impact on cardiac electrophysiology. In the AF setting, perfusion with dapagliflozin showed significant suppression of AF in the course of restitution of electrophysiological parameters whereas empagliflozin showed no significant effect on atrial fibrillation incidence. Conclusion In this model, empagliflozin and dapagliflozin demonstrated opposite antiarrhythmic properties. Empagliflozin reduced ventricular tachyarrhythmias whereas dapagliflozin showed effective suppression of atrial arrhythmias.
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Affiliation(s)
- Julian Wolfes
- Department of Cardiology II, Electrophysiology, University Hospital Münster, Münster, Germany
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Könemann H, Dagres N, Merino JL, Sticherling C, Zeppenfeld K, Tfelt-Hansen J, Eckardt L. Spotlight on the 2022 ESC guideline management of ventricular arrhythmias and prevention of sudden cardiac death: 10 novel key aspects. Europace 2023; 25:euad091. [PMID: 37102266 PMCID: PMC10228619 DOI: 10.1093/europace/euad091] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 03/13/2023] [Indexed: 04/28/2023] Open
Abstract
Sudden cardiac death and ventricular arrhythmias are a global health issue. Recently, a new guideline for the management of ventricular arrhythmias and prevention of sudden cardiac death has been published by the European Society of Cardiology that serves as an update to the 2015 guideline on this topic. This review focuses on 10 novel key aspects of the current guideline: As new aspects, public basic life support and access to defibrillators are guideline topics. Recommendations for the diagnostic evaluation of patients with ventricular arrhythmias are structured according to frequently encountered clinical scenarios. Management of electrical storm has become a new focus. In addition, genetic testing and cardiac magnetic resonance imaging significantly gained relevance for both diagnostic evaluation and risk stratification. New algorithms for antiarrhythmic drug therapy aim at improving safe drug use. The new recommendations reflect increasing relevance of catheter ablation of ventricular arrhythmias, especially in patients without structural heart disease or stable coronary artery disease with only mildly impaired ejection fraction and haemodynamically tolerated ventricular tachycardias. Regarding sudden cardiac death risk stratification, risk calculators for laminopathies, and long QT syndrome are now considered besides the already established risk calculator for hypertrophic cardiomyopathy. Generally, 'new' risk markers beyond left ventricular ejection fraction are increasingly considered for recommendations on primary preventive implantable cardioverter defibrillator therapy. Furthermore, new recommendations for diagnosis of Brugada syndrome and management of primary electrical disease have been included. With many comprehensive flowcharts and practical algorithms, the new guideline takes a step towards a user-oriented reference book.
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Affiliation(s)
- Hilke Könemann
- Department of Cardiology II: Electrophysiology, University Hospital Münster, Albert-Schweitzer Campus 1, 48149 Münster, Germany
| | - Nikolaos Dagres
- Department of Cardiac Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - José Luis Merino
- Cardiology Department, La Paz University Hospital, Madrid, Spain
| | | | - Katja Zeppenfeld
- Department of Cardiology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jacob Tfelt-Hansen
- Section of Genetics, Department of Forensic Medicine, Faculty of Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- The Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Lars Eckardt
- Department of Cardiology II: Electrophysiology, University Hospital Münster, Albert-Schweitzer Campus 1, 48149 Münster, Germany
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Ellermann C, Hakenes T, Wolfes J, Wegner FK, Willy K, Leitz P, Rath B, Eckardt L, Frommeyer G. Cardiovascular risk of energy drinks:Caffeine and taurine facilitate ventricular arrhythmias in a sensitive whole-heart model. J Cardiovasc Electrophysiol 2022; 33:1290-1297. [PMID: 35304782 DOI: 10.1111/jce.15458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 01/19/2022] [Accepted: 02/20/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND Several case reports have suggested an increased risk of sudden cardiac death due to energy drinks. Therefore, purpose of this study was to assess acute electrophysiologic effects of caffeine and taurine, two of the main ingredients of energy drinks, in an experimental whole-heart model. METHODS AND RESULTS 25 rabbit hearts were excised, retrogradely perfused and assigned to two groups. Hearts were perfused with caffeine (2, 10, 50 µM) or taurine (2, 10, 50 µM) after generating baseline data. Eight monophasic action potentials and ECG recordings showed a significant abbreviation of action potential duration (APD90 ), QT interval and effective refractory periods (ERP) after caffeine treatment. With taurine, cardiac repolarization duration and ERP were significantly shortened. Ventricular vulnerability was assessed by a predefined pacing protocol. With caffeine, we observed a trend towards more ventricular arrhythmias in a dose-dependent manner. After treatment with taurine, significantly more episodes of ventricular arrhythmias occurred. CONCLUSION In this experimental whole-heart study, treatment with caffeine and taurine provoked ventricular arrhythmias. Underlying mechanism was an abbreviation of cardiac repolarizations and effective refractory periods that may facilitate re-entry and thereby provokes arrhythmias. These findings help to understand the potentially hazardous and fatal outcomes after intoxication with energy drinks. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Christian Ellermann
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Tamara Hakenes
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Julian Wolfes
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Felix K Wegner
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Kevin Willy
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Patrick Leitz
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Benjamin Rath
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Lars Eckardt
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Gerrit Frommeyer
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
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Ellermann C, Dimanski D, Wolfes J, Rath B, Leitz P, Willy K, Wegner FK, Eckardt L, Frommeyer G. Electrophysiologic effects of sacubitril in different arrhythmia models. Eur J Pharmacol 2022; 917:174747. [PMID: 35026194 DOI: 10.1016/j.ejphar.2022.174747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND Previous studies report conflicting data regarding anti- or proarrhythmic effects of sacubitril. Aim of this study was to assess the impact of acute sacubitril treatment in different arrhythmia models. METHODS Sacubitril was administered (3, 5, 10 μM) in 12 isolated rabbit hearts. Further 12 hearts were treated with erythromycin to simulate long-QT-syndrome-2 (LQT2). Other 12 hearts were perfused with veratridine to mimic long-QT-syndrome-3 (LQT3). Both LQT-groups were treated with sacubitril (5 μM) additionally. Ventricular vulnerability was assessed by a pacing protocol. AV-blocked bradycardic hearts were perfused with a hypokalemic solution to trigger torsade de pointes (TdP). In further 13 hearts, AF was induced by a combination of acetylcholine and isoproterenol and sacubitril (5 μM) was added afterwards. RESULTS With sacubitril, action potential duration (APD) was abbreviated whereas spatial dispersion of repolarisation (SDR) remained stable. In both LQT groups, APD and SDR were increased. Infusion of sacubitril reduced APD (- 21 ms, p < 0.01) and SDR (- 8 ms) in the LQT2-group and did not alter APD (+2 ms) but reduced SDR (-19 ms, p < 0.01) in the LQT3-group. Ventricular vulnerability was not altered by sacubitril. No TdP were observed with sacubitril or under baseline conditions in any group. Sacubitril significantly suppressed TdP in the LQT2-group (3 vs. 43 episodes, p < 0.05) but not in the LQT3-group (10 vs. 16 episodes, p = ns). Sacubitril reduced inducibility of AF (9 vs. 31 episodes). CONCLUSION Sacubitril abbreviated APD. In addition, sacubitril exhibits potential antiarrhythmic effects in LQT2 and may be beneficial in LQT3 and AF.
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Affiliation(s)
- Christian Ellermann
- Department of Cardiology II (Electrophysiology), University Hospital, Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany.
| | - Darian Dimanski
- Department of Cardiology II (Electrophysiology), University Hospital, Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Julian Wolfes
- Department of Cardiology II (Electrophysiology), University Hospital, Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Benjamin Rath
- Department of Cardiology II (Electrophysiology), University Hospital, Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Patrick Leitz
- Department of Cardiology II (Electrophysiology), University Hospital, Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Kevin Willy
- Department of Cardiology II (Electrophysiology), University Hospital, Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Felix K Wegner
- Department of Cardiology II (Electrophysiology), University Hospital, Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Lars Eckardt
- Department of Cardiology II (Electrophysiology), University Hospital, Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - Gerrit Frommeyer
- Department of Cardiology II (Electrophysiology), University Hospital, Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
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Ballet V, Bohme GA, Brohan E, Boukaiba R, Chambard JM, Angouillant-Boniface O, Carriot T, Chantoiseau C, Fouconnier S, Houtmann S, Prévost C, Schombert B, Schio L, Partiseti M. In vitro ion channel profile and ex vivo cardiac electrophysiology properties of the R(-) and S(+) enantiomers of hydroxychloroquine. Eur J Pharmacol 2022; 915:174670. [PMID: 34863995 DOI: 10.1016/j.ejphar.2021.174670] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 12/01/2021] [Accepted: 12/01/2021] [Indexed: 11/03/2022]
Abstract
Hydroxychloroquine (HCQ) is a derivative of the antimalaria drug chloroquine primarily prescribed for autoimmune diseases. Recent attempts to repurpose HCQ in the treatment of corona virus disease 2019 has raised concerns because of its propensity to prolong the QT-segment on the electrocardiogram, an effect associated with increased pro-arrhythmic risk. Since chirality can affect drug pharmacological properties, we have evaluated the functional effects of the R(-) and S(+) enantiomers of HCQ on six ion channels contributing to the cardiac action potential and on electrophysiological parameters of isolated Purkinje fibers. We found that R(-)HCQ and S(+)HCQ block human Kir2.1 and hERG potassium channels in the 1 μM-100 μM range with a 2-4 fold enantiomeric separation. NaV1.5 sodium currents and CaV1.2 calcium currents, as well as KV4.3 and KV7.1 potassium currents remained unaffected at up to 90 μM. In rabbit Purkinje fibers, R(-)HCQ prominently depolarized the membrane resting potential, inducing autogenic activity at 10 μM and 30 μM, while S(+)HCQ primarily increased the action potential duration, inducing occasional early afterdepolarization at these concentrations. These data suggest that both enantiomers of HCQ can alter cardiac tissue electrophysiology at concentrations above their plasmatic levels at therapeutic doses, and that chirality does not substantially influence their arrhythmogenic potential in vitro.
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Affiliation(s)
- Véronique Ballet
- Preclinical Safety Investigative Toxicology, Sanofi-Aventis R&D, Chilly-Mazarin, France
| | - G Andrees Bohme
- High Content Biology, Integrated Drug Discovery, Sanofi-Aventis R&D, Vitry-sur-Seine, France.
| | - Eric Brohan
- Early Development, Advanced Preparative Chromatography, Sanofi-Aventis R&D, Vitry-sur-Seine, France
| | - Rachid Boukaiba
- High Content Biology, Integrated Drug Discovery, Sanofi-Aventis R&D, Vitry-sur-Seine, France
| | - Jean-Marie Chambard
- High Content Biology, Integrated Drug Discovery, Sanofi-Aventis R&D, Vitry-sur-Seine, France
| | | | - Thierry Carriot
- Preclinical Safety Investigative Toxicology, Sanofi-Aventis R&D, Chilly-Mazarin, France
| | - Céline Chantoiseau
- High Content Biology, Integrated Drug Discovery, Sanofi-Aventis R&D, Vitry-sur-Seine, France
| | - Sophie Fouconnier
- High Content Biology, Integrated Drug Discovery, Sanofi-Aventis R&D, Vitry-sur-Seine, France
| | - Sylvie Houtmann
- High Content Biology, Integrated Drug Discovery, Sanofi-Aventis R&D, Vitry-sur-Seine, France
| | - Céline Prévost
- Early Development, Advanced Preparative Chromatography, Sanofi-Aventis R&D, Vitry-sur-Seine, France
| | - Brigitte Schombert
- High Content Biology, Integrated Drug Discovery, Sanofi-Aventis R&D, Vitry-sur-Seine, France
| | - Laurent Schio
- Integrated Drug Discovery, Sanofi-Aventis R&D, Vitry-sur-Seine, France
| | - Michel Partiseti
- High Content Biology, Integrated Drug Discovery, Sanofi-Aventis R&D, Vitry-sur-Seine, France
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Safe electrophysiologic profile of dexmedetomidine in different experimental arrhythmia models. Sci Rep 2021; 11:23940. [PMID: 34907251 PMCID: PMC8671395 DOI: 10.1038/s41598-021-03364-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 11/23/2021] [Indexed: 12/14/2022] Open
Abstract
Previous studies suggest an impact of dexmedetomidine on cardiac electrophysiology. However, experimental data is sparse. Therefore, purpose of this study was to investigate the influence of dexmedetomidine on different experimental models of proarrhythmia. 50 rabbit hearts were explanted and retrogradely perfused. The first group (n = 12) was treated with dexmedetomidine in ascending concentrations (3, 5 and 10 µM). Dexmedetomidine did not substantially alter action potential duration (APD) but reduced spatial dispersion of repolarization (SDR) and rendered the action potentials rectangular, resulting in no proarrhythmia. In further 12 hearts, erythromycin (300 µM) was administered to simulate long-QT-syndrome-2 (LQT2). Additional treatment with dexmedetomidine reduced SDR, thereby suppressing torsade de pointes. In the third group (n = 14), 0.5 µM veratridine was added to reduce the repolarization reserve. Further administration of dexmedetomidine did not influence APD, SDR or the occurrence of arrhythmias. In the last group (n = 12), a combination of acetylcholine (1 µM) and isoproterenol (1 µM) was used to facilitate atrial fibrillation. Additional treatment with dexmedetomidine prolonged the atrial APD but did not reduce AF episodes. In this study, dexmedetomidine did not significantly alter cardiac repolarization duration and was not proarrhythmic in different models of ventricular and atrial arrhythmias. Of note, dexmedetomidine might be antiarrhythmic in acquired LQT2 by reducing SDR.
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