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Fender J, Klöcker J, Boivin-Jahns V, Ravens U, Jahns R, Lorenz K. "Cardiac glycosides"-quo vaditis?-past, present, and future? NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024:10.1007/s00210-024-03285-3. [PMID: 39007928 DOI: 10.1007/s00210-024-03285-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Accepted: 07/03/2024] [Indexed: 07/16/2024]
Abstract
Up to date, digitalis glycosides, also known as "cardiac glycosides", are inhibitors of the Na+/K+-ATPase. They have a long-standing history as drugs used in patients suffering from heart failure and atrial fibrillation despite their well-known narrow therapeutic range and the intensive discussions on their raison d'être for these indications. This article will review the history and key findings in basic and clinical research as well as potentially overseen pros and cons of these drugs.
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Affiliation(s)
- Julia Fender
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Straße 9, 97078, Würzburg, Germany
| | - Johanna Klöcker
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Straße 9, 97078, Würzburg, Germany
| | - Valérie Boivin-Jahns
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Straße 9, 97078, Würzburg, Germany
| | - Ursula Ravens
- Institute of Experimental Cardiovascular Medicine, Faculty of Medicine, University of Freiburg, Elsässer Straße 2Q, 79110, Freiburg, Germany
| | - Roland Jahns
- Interdisciplinary Bank of Biological Materials and Data Würzburg (ibdw), University Hospital Würzburg, Straubmühlweg 2a, 97078, Würzburg, Germany
| | - Kristina Lorenz
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Straße 9, 97078, Würzburg, Germany.
- Leibniz-Institut für Analytische Wissenschaften-ISAS e.V., Bunsen-Kirchhoff-Straße 11, 44139, Dortmund, Germany.
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2
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Davis CC, Choisy P. Medicinal plants meet modern biodiversity science. Curr Biol 2024; 34:R158-R173. [PMID: 38412829 DOI: 10.1016/j.cub.2023.12.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Plants have been an essential source of human medicine for millennia. In this review, we argue that a holistic, interdisciplinary approach to the study of medicinal plants that combines methods and insights from three key disciplines - evolutionary ecology, molecular biology/biochemistry, and ethnopharmacology - is poised to facilitate new breakthroughs in science, including pharmacological discoveries and rapid advancements in human health and well-being. Such interdisciplinary research leverages data and methods spanning space, time, and species associated with medicinal plant species evolution, ecology, genomics, and metabolomic trait diversity, all of which build heavily on traditional Indigenous knowledge. Such an interdisciplinary approach contrasts sharply with most well-funded and successful medicinal plant research during the last half-century, which, despite notable advancements, has greatly oversimplified the dynamic relationships between plants and humans, kept hidden the larger human narratives about these relationships, and overlooked potentially important research and discoveries into life-saving medicines. We suggest that medicinal plants and people should be viewed as partners whose relationship involves a complicated and poorly explored set of (socio-)ecological interactions including not only domestication but also commensalisms and mutualisms. In short, medicinal plant species are not just chemical factories for extraction and exploitation. Rather, they may be symbiotic partners that have shaped modern societies, improved human health, and extended human lifespans.
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Affiliation(s)
- Charles C Davis
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA 02138, USA.
| | - Patrick Choisy
- LVMH Research, 185 Avenue de Verdun, 45804 Saint Jean de Braye CEDEX, France
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3
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Clifford LM, Meere W. Chronic Digoxin Toxicity: An Evaluation of Digoxin-Specific Antibodies and Other Management Options. Cureus 2023; 15:e38692. [PMID: 37292530 PMCID: PMC10245077 DOI: 10.7759/cureus.38692] [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] [Accepted: 05/07/2023] [Indexed: 06/10/2023] Open
Abstract
Chronic digoxin toxicity comprises the bulk of digoxin poisonings and can be more difficult to manage than acute intoxications. A 60-year-old lady presented with severe chronic digoxin toxicity after ingesting digoxin 250mcg twice a day (BD) for two weeks. Due to hemodynamic instability on presentation, she was treated with digoxin-specific antibodies and admitted to the coronary care unit. This case of chronic digoxin toxicity did not respond to digoxin-specific antibodies and required intensive cardiac therapy with isoprenaline and intravenous electrolyte replacement, highlighting the complexities in the management of toxicity. Our patient has since recovered and remains stable. There are newer, novel therapies being trialed for the treatment of digoxin toxicity, including dextrose-insulin infusions, therapeutic plasma exchange, and rifampicin, but these require more research and investigation in this cohort of patients.
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4
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MacLeod KT. Changes in cellular Ca 2+ and Na + regulation during the progression towards heart failure. J Physiol 2023; 601:905-921. [PMID: 35946572 PMCID: PMC10952717 DOI: 10.1113/jp283082] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/02/2022] [Indexed: 11/08/2022] Open
Abstract
In adapting to disease and loss of tissue, the heart shows great phenotypic plasticity that involves changes to its structure, composition and electrophysiology. Together with parallel whole body cardiovascular adaptations, the initial decline in cardiac function resulting from the insult is compensated. However, in the long term, the heart muscle begins to fail and patients with this condition have a very poor prognosis, with many dying from disturbances of rhythm. The surviving myocytes of these hearts gain Na+ , which is positively inotropic because of alterations to Ca2+ fluxes mediated by the Na+ /Ca2+ exchange, but compromises Ca2+ -dependent energy metabolism in mitochondria. Uptake of Ca2+ into the sarcoplasmic reticulum (SR) is reduced because of diminished function of SR Ca2+ ATPases. The result of increased Ca2+ influx and reduced SR Ca2+ uptake is an increase in the diastolic cytosolic Ca2+ concentration, which promotes spontaneous SR Ca2+ release and induces delayed afterdepolarisations. Action potential duration prolongs because of increased late Na+ current and changes in expression and function of other ion channels and transporters increasing the probability of the formation of early afterdepolarisations. There is a reduction in T-tubule density and so the normal spatial arrangements required for efficient excitation-contraction coupling are compromised and lead to temporal delays in Ca2+ release from the SR. Therefore, the structural and electrophysiological responses that occur to provide compensation do so at the expense of (1) increasing the likelihood of arrhythmogenesis; (2) activating hypertrophic, apoptotic and Ca2+ signalling pathways; and (3) decreasing the efficiency of SR Ca2+ release.
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Affiliation(s)
- Kenneth T. MacLeod
- National Heart & Lung InstituteImperial Centre for Translational and Experimental MedicineImperial CollegeHammersmith HospitalLondonUK
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5
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Hartmann JP, Dahl RH, Nymand S, Munch GW, Ryrsø CK, Pedersen BK, Thaning P, Mortensen SP, Berg RMG, Iepsen UW. Regulation of the microvasculature during small muscle mass exercise in chronic obstructive pulmonary disease vs. chronic heart failure. Front Physiol 2022; 13:979359. [PMID: 36134330 PMCID: PMC9483770 DOI: 10.3389/fphys.2022.979359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/08/2022] [Indexed: 11/21/2022] Open
Abstract
Aim: Skeletal muscle convective and diffusive oxygen (O2) transport are peripheral determinants of exercise capacity in both patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). We hypothesised that differences in these peripheral determinants of performance between COPD and CHF patients are revealed during small muscle mass exercise, where the cardiorespiratory limitations to exercise are diminished. Methods: Eight patients with moderate to severe COPD, eight patients with CHF (NYHA II), and eight age- and sex-matched controls were studied. We measured leg blood flow (Q̇leg) by Doppler ultrasound during submaximal one-legged knee-extensor exercise (KEE), while sampling arterio-venous variables across the leg. The capillary oxyhaemoglobin dissociation curve was reconstructed from paired femoral arterial-venous oxygen tensions and saturations, which enabled the estimation of O2 parameters at the microvascular level within skeletal muscle, so that skeletal muscle oxygen conductance (DSMO2) could be calculated and adjusted for flow (DSMO2/Q̇leg) to distinguish convective from diffusive oxygen transport. Results: During KEE, Q̇leg increased to a similar extent in CHF (2.0 (0.4) L/min) and controls (2.3 (0.3) L/min), but less in COPD patients (1.8 (0.3) L/min) (p <0.03). There was no difference in resting DSMO2 between COPD and CHF and when adjusting for flow, the DSMO2 was higher in both groups compared to controls (COPD: 0.97 (0.23) vs. controls 0.63 (0.24) mM/kPa, p= 0.02; CHF 0.98 (0.11) mM/kPa vs. controls, p= 0.001). The Q̇-adjusted DSMO2 was not different in COPD and CHF during KEE (COPD: 1.19 (0.11) vs. CHF: 1.00 (0.18) mM/kPa; p= 0.24) but higher in COPD vs. controls: 0.87 (0.28) mM/kPa (p= 0.02), and only CHF did not increase Q̇-adjusted DSMO2 from rest (p= 0.2). Conclusion: Disease-specific factors may play a role in peripheral exercise limitation in patients with COPD compared with CHF. Thus, low convective O2 transport to contracting muscle seemed to predominate in COPD, whereas muscle diffusive O2 transport was unresponsive in CHF.
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Affiliation(s)
- Jacob Peter Hartmann
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Rasmus H. Dahl
- Department of Radiology, Hvidovre Hospital, Copenhagen, Denmark
- Department of Radiology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Stine Nymand
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gregers W. Munch
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Camilla K. Ryrsø
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Pulmonary and Infectious Diseases, Copenhagen University Hospital, North Zealand, Hillerød, Denmark
| | - Bente K. Pedersen
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Pia Thaning
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Respiratory Medicine, Copenhagen University Hospital, Hvidovre Hospital, Copenhagen, Denmark
| | - Stefan P. Mortensen
- Department of Cardiovascular and Renal Research, University of Southern Denmark, Copenhagen, Denmark
| | - Ronan M. G. Berg
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, United Kingdom
| | - Ulrik Winning Iepsen
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Anaesthesiology and Intensive Care, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark
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6
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Effectiveness of amiodarone versus digitalis for heart rate control in critically ill patients with new-onset atrial fibrillation. Sci Rep 2022; 12:2712. [PMID: 35177703 PMCID: PMC8854600 DOI: 10.1038/s41598-022-06639-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/17/2022] [Indexed: 11/08/2022] Open
Abstract
New-onset of atrial fibrillation (NOAF) in critically ill patients is the most common acute cardiac dysrhythmia, but evidence-based data regarding treatment strategies are scarce. In this retrospective monocentric study, we compared effectiveness of amiodarone versus digitalis for heart rate control in critically ill patients with new-onset of atrial fibrillation. We identified a total of 209 patients for the main analysis. Amiodarone as compared to digitalis was associated with a clinically relevant faster time to heart rate control < 110 bpm (2 h (IQR: 1 h to 6 h) versus 4 h (2 h to 12 h); p = 0.003) and longer durations of sinus rhythm during the first 24 h of treatment (6 h (IQR: 6 h to 22 h) versus 0 h (IQR: 0 h to 16 h); p < 0.001). However, more bradycardic episodes occurred in association with amiodarone than with digitalis (7.7% versus 3.4%; p = 0.019). Use of amiodarone was associated with an increase of noradrenalin infusion rate compared to digitalis (23.9% versus 12.0%; p = 0.019). Within the tertile of patients with the highest CRP measurements, amiodarone treated patients presented with a higher decrease in heart rate than digoxin treated patients. Clinical trials comparing different NOAF treatment strategies are much needed and should report on concomitant sympathetic activity and inflammatory status.
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Stewart JM, Warsy IA, Visintainer P, Terilli C, Medow MS. Supine Parasympathetic Withdrawal and Upright Sympathetic Activation Underly Abnormalities of the Baroreflex in Postural Tachycardia Syndrome: Effects of Pyridostigmine and Digoxin. Hypertension 2021; 77:1234-1244. [PMID: 33423527 PMCID: PMC7946724 DOI: 10.1161/hypertensionaha.120.16113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Julian M Stewart
- From the Department of Pediatrics (J.M.S., I.A.W., C.T., M.S.M.), New York Medical College, Valhalla.,Departments of Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla
| | - Irfan A Warsy
- From the Department of Pediatrics (J.M.S., I.A.W., C.T., M.S.M.), New York Medical College, Valhalla
| | - Paul Visintainer
- Baystate Medical Center, University of Massachusetts School of Medicine, Worcester (P.V.)
| | - Courtney Terilli
- From the Department of Pediatrics (J.M.S., I.A.W., C.T., M.S.M.), New York Medical College, Valhalla
| | - Marvin S Medow
- From the Department of Pediatrics (J.M.S., I.A.W., C.T., M.S.M.), New York Medical College, Valhalla.,Departments of Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla
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8
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Geng M, Lin A, Nguyen TP. Revisiting Antiarrhythmic Drug Therapy for Atrial Fibrillation: Reviewing Lessons Learned and Redefining Therapeutic Paradigms. Front Pharmacol 2020; 11:581837. [PMID: 33240090 PMCID: PMC7680856 DOI: 10.3389/fphar.2020.581837] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Abstract
Since the clinical use of digitalis as the first pharmacological therapy for atrial fibrillation (AF) 235 years ago in 1785, antiarrhythmic drug therapy has advanced considerably and become a cornerstone of AF clinical management. Yet, a preventive or curative panacea for sustained AF does not exist despite the rise of AF global prevalence to epidemiological proportions. While multiple elevated risk factors for AF have been established, the natural history and etiology of AF remain incompletely understood. In the present article, the first section selectively highlights some disappointing shortcomings and current efforts in antiarrhythmic drug therapy to uncover reasons why AF is such a clinical challenge. The second section discusses some modern takes on the natural history of AF as a relentless, progressive fibro-inflammatory "atriomyopathy." The final section emphasizes the need to redefine therapeutic strategies on par with new insights of AF pathophysiology.
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Affiliation(s)
| | | | - Thao P. Nguyen
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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9
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Ferrari F, Santander IRMF, Stein R. Digoxin in Atrial Fibrillation: An Old Topic Revisited. Curr Cardiol Rev 2020; 16:141-146. [PMID: 31237216 PMCID: PMC7460705 DOI: 10.2174/1573403x15666190618110941] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/28/2019] [Accepted: 04/29/2019] [Indexed: 12/19/2022] Open
Abstract
Digoxin has been used for more than 50 years in patients with Atrial Fibrillation (AF), with the goal of Controlling Heart Rate (HR) and restoring sinus rhythm. In the last two decades, several studies have correlated therapeutic use of digoxin with increased mortality. However, such studies have potential biases that cannot be disregarded, mainly because they are cross-sectional experiments or post-hoc analyses of Randomized Controlled Trials (RCTs). Despite uncertainties regarding the safety of digoxin in this setting, it remains one of the most prescribed drugs for AF worldwide. On the other hand, the absence of any RCTs designed to evaluate mortality makes a definitive conclusion more difficult to reach; therefore, this medication must be used with care. In this review, we explored the therapeutic use of digoxin in the context of AF, discussed mortality data by means of critical analysis in the light of the best available evidence, and position ourselves in relation to more rigorous control of serum levels of this drug in daily practice.
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Affiliation(s)
- Filipe Ferrari
- Graduate Program in Cardiology and Cardiovascular Sciences, School of Medicine, Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Exercise Cardiology Research Group (CardioEx) HCPA/UFRGS, Porto Alegre, Brazil
| | | | - Ricardo Stein
- Graduate Program in Cardiology and Cardiovascular Sciences, School of Medicine, Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Exercise Cardiology Research Group (CardioEx) HCPA/UFRGS, Porto Alegre, Brazil.,School of Medicine, HCPA/UFRGS, Porto Alegre, Brazil
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10
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Zandstra T, Kiès P, Man SC, Maan A, Bootsma M, Vliegen H, Egorova A, Holman E, Schalij M, Jongbloed M. QT interval variability and heart rate turbulence are associated with clinical characteristics in congenital heart disease patients with a systemic right ventricle. J Cardiol 2020; 76:514-520. [PMID: 32665161 DOI: 10.1016/j.jjcc.2020.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/09/2020] [Accepted: 05/20/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND QT interval variability (QTV) and heart rate turbulence (HRT) are measures of cardiac autonomic function, which, when abnormal, are correlated with ventricular arrhythmias and worse clinical outcome. This study aims to evaluate QTV and HRT in patients with a systemic right ventricle (RV) and to assess correlations with clinical characteristics. METHODS In a retrospective cohort study, QTV and HRT were derived from 24-h Holter registrations of patients with a systemic RV and healthy controls. QTV and HRT were compared between groups. In patients, the association between QTV, HRT, and clinical characteristics was assessed. RESULTS Holter recordings from 40 patients (mean age 40 years, 16 females) and 37 healthy controls (mean age 42 years, 21 females) were analyzed. Groups were comparable in terms of age and sex. QTV was increased in patients compared with controls (p < 0.001), HRT did not differ significantly between the groups. Increased QTV and decreased HRT correlated with medication use, especially of diuretics, and with clinical events, particularly supraventricular arrhythmias. Increased QTV correlated with reduced systemic RV function. Decreased HRT was independently associated with a larger number of past clinical events (estimate -0.33, 95% CI -0.63 to -0.02, p = 0.037). QTV was higher in women in both patients and controls (p = 0.041 and p = 0.034, respectively). CONCLUSIONS QTV and HRT are associated with clinical factors and events in patients with a systemic RV. Further studies are mandatory to confirm their prognostic value.
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Affiliation(s)
- Tjitske Zandstra
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Philippine Kiès
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Sum-Che Man
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Arie Maan
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Marianne Bootsma
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Hubert Vliegen
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Anastasia Egorova
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Eduard Holman
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Martin Schalij
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Monique Jongbloed
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands; Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands.
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11
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Pott A, Bock S, Berger IM, Frese K, Dahme T, Keßler M, Rinné S, Decher N, Just S, Rottbauer W. Mutation of the Na +/K +-ATPase Atp1a1a.1 causes QT interval prolongation and bradycardia in zebrafish. J Mol Cell Cardiol 2018; 120:42-52. [PMID: 29750993 DOI: 10.1016/j.yjmcc.2018.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/24/2018] [Accepted: 05/07/2018] [Indexed: 02/01/2023]
Abstract
The genetic underpinnings that orchestrate the vertebrate heart rate are not fully understood yet, but of high clinical importance, since diseases of cardiac impulse formation and propagation are common and severe human arrhythmias. To identify novel regulators of the vertebrate heart rate, we deciphered the pathogenesis of the bradycardia in the homozygous zebrafish mutant hiphop (hip) and identified a missense-mutation (N851K) in Na+/K+-ATPase α1-subunit (atp1a1a.1). N851K affects zebrafish Na+/K+-ATPase ion transport capacity, as revealed by in vitro pump current measurements. Inhibition of the Na+/K+-ATPase in vivo indicates that hip rather acts as a hypomorph than being a null allele. Consequently, reduced Na+/K+-ATPase function leads to prolonged QT interval and refractoriness in the hip mutant heart, as shown by electrocardiogram and in vivo electrical stimulation experiments. We here demonstrate for the first time that Na+/K+-ATPase plays an essential role in heart rate regulation by prolonging myocardial repolarization.
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Affiliation(s)
- Alexander Pott
- Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany
| | - Sarah Bock
- Molecular Cardiology, Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany
| | - Ina M Berger
- Molecular Cardiology, Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany
| | - Karen Frese
- Department of Internal Medicine III, Heidelberg University Medical Center, Heidelberg, Germany
| | - Tillman Dahme
- Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany
| | - Mirjam Keßler
- Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Niels Decher
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Steffen Just
- Molecular Cardiology, Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany.
| | - Wolfgang Rottbauer
- Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany.
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12
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Lam PH, Bhyan P, Arundel C, Dooley DJ, Sheriff HM, Mohammed SF, Fonarow GC, Morgan CJ, Aronow WS, Allman RM, Waagstein F, Ahmed A. Digoxin use and lower risk of 30-day all-cause readmission in older patients with heart failure and reduced ejection fraction receiving β-blockers. Clin Cardiol 2018; 41:406-412. [PMID: 29569405 DOI: 10.1002/clc.22889] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 12/29/2017] [Accepted: 01/03/2018] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Digoxin use has been associated with a lower risk of 30-day all-cause admission and readmission in patients with heart failure and reduced ejection fraction (HFrEF). HYPOTHESIS Digoxin use will be associated with improved outcomes in patients with HFrEF receiving β-blockers. METHODS Of the 3076 hospitalized Medicare beneficiaries with HFrEF (EF <45%), 1046 received a discharge prescription for β-blockers, of which 634 were not on digoxin. Of the 634, 204 received a new discharge prescription for digoxin. Propensity scores for digoxin use, estimated for each of the 634 patients, were used to assemble a matched cohort of 167 pairs of patients receiving and not receiving digoxin, balanced on 30 baseline characteristics. Matched patients (n = 334) had a mean age of 74 years and were 46% female and 30% African American. RESULTS 30-day all-cause readmission occurred in 15% and 27% of those receiving and not receiving digoxin, respectively (hazard ratio [HR]: 0.51, 95% confidence interval [CI]: 0.31-0.83, P = 0.007). This beneficial association persisted during 4 years of follow-up (HR: 0.72, 95% CI: 0.57-0.92, P = 0.008). Digoxin use was also associated with a lower risk of the combined endpoint of all-cause readmission or all-cause mortality at 30 days (HR: 0.54, 95% CI: 0.34-0.86, P = 0.009) and at 4 years (HR: 0.76, 95% CI: 0.61-0.96, P = 0.020). CONCLUSIONS In hospitalized patients with HFrEF receiving β-blockers, digoxin use was associated with a lower risk of 30-day all-cause readmission but not mortality, which persisted during longer follow-up.
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Affiliation(s)
- Phillip H Lam
- Department of Medicine, Veterans Affairs Medical Center, Washington, D.C.,Department of Medicine, Georgetown University/MedStar Washington Hospital Center, Washington, D.C
| | - Poonam Bhyan
- Department of Medicine, Veterans Affairs Medical Center, Washington, D.C.,Department of Medicine, Georgetown University/MedStar Washington Hospital Center, Washington, D.C
| | - Cherinne Arundel
- Department of Medicine, Veterans Affairs Medical Center, Washington, D.C.,Department of Medicine, George Washington University, Washington, D.C
| | - Daniel J Dooley
- Department of Medicine, Veterans Affairs Medical Center, Washington, D.C.,Department of Medicine, Georgetown University/MedStar Washington Hospital Center, Washington, D.C
| | - Helen M Sheriff
- Department of Medicine, Veterans Affairs Medical Center, Washington, D.C.,Department of Medicine, George Washington University, Washington, D.C
| | - Selma F Mohammed
- MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, D.C
| | - Gregg C Fonarow
- Ahmanson-UCLA Cardiomyopathy Center, University of California, Los Angeles
| | - Charity J Morgan
- Department of Biostatistics, University of Alabama at Birmingham
| | - Wilbert S Aronow
- Department of Medicine, Westchester Medical Center and New York Medical College, Valhalla, New York
| | - Richard M Allman
- Office of Geriatrics and Extended Care, Department of Veterans Affairs, Washington, D.C
| | - Finn Waagstein
- Department of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Ali Ahmed
- Department of Medicine, Veterans Affairs Medical Center, Washington, D.C.,Department of Medicine, George Washington University, Washington, D.C
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13
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Gupta A, Dakkak M, Miller A. Digoxin and Heart Failure: Are We Clear Yet? CARDIOVASCULAR INNOVATIONS AND APPLICATIONS 2017. [DOI: 10.15212/cvia.2016.0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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14
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Addition of beta-blockers to digoxin is associated with improved 1- and 10-year survival of patients hospitalized due to decompensated heart failure. Int J Cardiol 2016; 221:198-204. [DOI: 10.1016/j.ijcard.2016.06.202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/12/2016] [Accepted: 06/25/2016] [Indexed: 11/17/2022]
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15
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Kasliwal RR, Mukesh S, Manohar G, Aggarwal N, Bhatia A. Pharmacotherapy of Atrial Fibrillation. Asian Cardiovasc Thorac Ann 2016; 11:364-74. [PMID: 14681106 DOI: 10.1177/021849230301100424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Atrial fibrillation is the most common sustained arrhythmia of clinical significance. Its prevalence rises with age. It is a significant cause of thromboembolic phenomena. We describe briefly the etiology and classification of atrial fibrillation, the risk factors for thromboembolism and stroke associated with it, the indications for hospitalization, and the therapeutic goal. We discuss in depth the management strategies for such patients and compare the impact of rate versus rhythm control in reducing morbidity and mortality attributed to arrhythmia, in light of past and present trials. A brief overview of the drugs used in the management of atrial fibrillation, their pharmacology and dosage, their effects and use in rhythm versus rate control with important side effects are also included. Finally, the prevention and treatment of thromboembolism in patients with atrial fibrillation, an important aspect of therapy, is revisited in light of recent advances.
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Affiliation(s)
- Ravi R Kasliwal
- Department of Cardiology, Escorts Heart Institute and Research Centre, Okhla Road, New Delhi 110-025, India.
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16
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Barrett-O'Keefe Z, Lee JF, Berbert A, Witman MAH, Nativi-Nicolau J, Stehlik J, Richardson RS, Wray DW. Hemodynamic responses to small muscle mass exercise in heart failure patients with reduced ejection fraction. Am J Physiol Heart Circ Physiol 2014; 307:H1512-20. [PMID: 25260608 DOI: 10.1152/ajpheart.00527.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To better understand the mechanisms responsible for exercise intolerance in heart failure with reduced ejection fraction (HFrEF), the present study sought to evaluate the hemodynamic responses to small muscle mass exercise in this cohort. In 25 HFrEF patients (64 ± 2 yr) and 17 healthy, age-matched control subjects (64 ± 2 yr), mean arterial pressure (MAP), cardiac output (CO), and limb blood flow were examined during graded static-intermittent handgrip (HG) and dynamic single-leg knee-extensor (KE) exercise. During HG exercise, MAP increased similarly between groups. CO increased significantly (+1.3 ± 0.3 l/min) in the control group, but it remained unchanged across workloads in HFrEF patients. At 15% maximum voluntary contraction (MVC), forearm blood flow was similar between groups, while HFrEF patients exhibited an attenuated increase at the two highest intensities compared with controls, with the greatest difference at the highest workload (352 ± 22 vs. 492 ± 48 ml/min, HFrEF vs. control, 45% MVC). During KE exercise, MAP and CO increased similarly across work rates between groups. However, HFrEF patients exhibited a diminished leg hyperemic response across all work rates, with the most substantial decrement at the highest intensity (1,842 ± 64 vs. 2,675 ± 81 ml/min; HFrEF vs. control, 15 W). Together, these findings indicate a marked attenuation in exercising limb perfusion attributable to impairments in peripheral vasodilatory capacity during both arm and leg exercise in patients with HFrEF, which likely plays a role in limiting exercise capacity in this patient population.
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Affiliation(s)
- Zachary Barrett-O'Keefe
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Joshua F Lee
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah
| | - Amanda Berbert
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Melissa A H Witman
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Jose Nativi-Nicolau
- Department of Internal Medicine, Division of Cardiology, University of Utah, Salt Lake City, Utah; and
| | - Josef Stehlik
- Department of Internal Medicine, Division of Cardiology, University of Utah, Salt Lake City, Utah; and
| | - Russell S Richardson
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; University of Utah Center on Aging, Salt Lake City, Utah
| | - D Walter Wray
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; University of Utah Center on Aging, Salt Lake City, Utah
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17
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Yu JH, Weng YM, Chen KF, Chen SY, Lin CC. Triage vital signs predict in-hospital mortality among emergency department patients with acute poisoning: a case control study. BMC Health Serv Res 2012; 12:262-9. [PMID: 22900613 PMCID: PMC3459725 DOI: 10.1186/1472-6963-12-262] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 08/15/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To document the relationship between triage vital signs and in-hospital mortality among emergency department (ED) patients with acute poisoning. METHODS Poisoning patients who admitted to our emergency department during the study period were enrolled. Patient's demographic data were collected and odds ratios (OR) of triage vital signs to in-hospital mortality were assessed. Receiver operating characteristic curve was used to determine the proper cut-off value of vital signs that predict in-hospital mortality. Logistic regression analysis was performed to test the association of in-hospital mortality and vital signs after adjusting for different variables. RESULTS 997 acute poisoning patients were enrolled, with 70 fatal cases (6.7%). A J-shaped relationship was found between triage vital signs and in-hospital mortality. ED triage vital signs exceed cut-off values independently predict in-hospital mortality after adjusting for variables were as follow: body temperature <36 or >37°C, p < 0.01, OR = 2.8; systolic blood pressure <100 or >150 mmHg, p < 0.01, OR: 2.5; heart rate <35 or >120 bpm, p < 0.01, OR: 3.1; respiratory rate <16 or >20 per minute, p = 0.38, OR: 1.4. CONCLUSIONS Triage vital signs could predict in-hospital mortality among ED patients with acute poisoning. A J-curve relationship was found between triage vital signs and in-hospital mortality. ED physicians should take note of the extreme initial vital signs in these patients.
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Affiliation(s)
- Jiun-Hao Yu
- Department of Emergency Medicine, Chang Gung Memorial Hospital, Linkou, No. 5, Fu-Hsing St., Kuei Shan Hsiang, Tao-yuan Hsien, Taiwan
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18
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Castagno D, Petrie MC, Claggett B, McMurray J. Should we SHIFT our thinking about digoxin? Observations on ivabradine and heart rate reduction in heart failure. Eur Heart J 2012; 33:1137-41. [DOI: 10.1093/eurheartj/ehs004] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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19
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Mogensen L. Digitalis--two hundred years. ACTA MEDICA SCANDINAVICA 2009; 220:97-100. [PMID: 3535394 DOI: 10.1111/j.0954-6820.1986.tb02736.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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20
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Tiamfook-Morgan TO, Brown DFM, Nadel ES. Bradycardia and confusion. J Emerg Med 2008; 34:451-455. [PMID: 18394851 DOI: 10.1016/j.jemermed.2008.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 03/06/2008] [Indexed: 05/26/2023]
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21
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Tamargo J, Delpón E, Caballero R. The safety of digoxin as a pharmacological treatment of atrial fibrillation. Expert Opin Drug Saf 2006; 5:453-67. [PMID: 16610972 DOI: 10.1517/14740338.5.3.453] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Digoxin has traditionally been the drug of choice for ventricular rate control in patients with chronic atrial fibrillation (AF), with or without heart failure (HF) with systolic dysfunction. In patients with permanent AF, digoxin monotherapy is ineffective to control ventricular rate during exercise, but the combination of digoxin with a beta-blocker or a non-dihydropyridine calcium channel antagonist can control heart rate both at rest and during exercise. Only a few randomised, controlled studies have evaluated the adverse effects of digoxin in patients with AF in a systematic way and side effects requiring drug withdrawal have rarely been reported. When reported, the most frequent adverse effects were cardiac arrhythmias (ventricular arrhythmias, AV block of varying degrees and sinus pauses). This evidence suggested that, in contrast to other antiarrhythmic drugs, digoxin is a safe drug in patients with AF. However, this safety profile can be erroneous due to the short follow-up of the studies and patient selection. Because patients with HF have been excluded in most studies, the safety profile of digoxin in this population has not been directly addressed. Early recognition that an arrhythmia is related to digoxin intoxication as well as recognition of concomitant medications or medical conditions that may directly alter the pharmacokinetic profile of digoxin, or indirectly alter its cardiac effects by pharmacodynamic interactions remain essential for safe and effective use of digoxin in patients with AF.
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Affiliation(s)
- Juan Tamargo
- Department of Pharmacology, School of Medicine, Universidad Complutense, 28040 Madrid, Spain.
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22
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Hoppe UC, Erdmann E. Digitalis in heart failure! Still applicable? ACTA ACUST UNITED AC 2005; 94:307-11. [PMID: 15868358 DOI: 10.1007/s00392-005-0219-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Accepted: 12/13/2004] [Indexed: 10/25/2022]
Abstract
In patients with heart failure and atrial fibrillation cardiac glycosides, generally in combination with beta-blockers, are indicated to control ventricular rate. In systolic heart failure and sinus rhythm, however, the use of digitalis continues to be debated. There are special concerns that cardiac glycosides might lead to an increased mortality rate in women. Retrospective analyses, however, do not indicate any sex-based differences in the effectiveness of cardiac glycosides. Beneficial effects of cardiac glycosides in heart failure seem to be related to the attenuation of sympathetic activation and neurohumoral alterations, which is already obtained at low digoxin serum concentrations, while high serum levels are associated with increased mortality. Therefore, in patients with sinus rhythm who remain symptomatic under an optimized therapy with ACE inhibitors, beta-blockers and diuretics in addition to digitalis should be considered regardless of the gender. However, target serum digoxin concentrations should be low in a range of 0.5 to 0.8 ng/ml.
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Affiliation(s)
- U C Hoppe
- Department of Internal Medicine III, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany.
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23
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Binkley PF, Nunziatta E, Liu-Stratton Y, Cooke G. A polymorphism of the endothelial nitric oxide synthase promoter is associated with an increase in autonomic imbalance in patients with congestive heart failure. Am Heart J 2005; 149:342-8. [PMID: 15846275 DOI: 10.1016/j.ahj.2004.05.059] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND In addition to its well-recognized role in the regulation of vascular tone, nitric oxide modulates sympathetic and parasympathetic nervous system activities. Abnormalities of both autonomic control and nitric oxide synthase activity are known to occur in patients with congestive heart failure. Recently, a polymorphism of the promoter of the endothelial nitric oxide synthase (eNOS) gene has been associated with a reduction of eNOS activity. This study tested the hypothesis that patients with congestive heart failure who are homozygous for this polymorphism will have a more advanced imbalance of autonomic activity. METHODS Patients who have congestive heart failure were tested for the presence of an eNOS promoter polymorphism (thymidine to cytosine transition [T(-786)C]). Spectral analysis of heart rate variability was performed to quantify sympathetic and parasympathetic autonomic activity, which were compared between subjects homozygous for the polymorphism and all other subjects. RESULTS Patients homozygous for the polymorphism of the eNOS promoter had a greater autonomic imbalance as reflected by significant differences in high- and low-frequency heart rate variability. These differences in autonomic function were noted in the absence of intergroup differences in patterns of respiratory variability, demographic features, and despite a higher mean ejection fraction in patients homozygous for the polymorphism. CONCLUSIONS Patients with congestive heart failure who are homozygous for this polymorphism of the eNOS promoter were found to have a more advanced autonomic imbalance. This polymorphism may serve as a marker for patients at increased risk for sudden death and more rapid progression of disease.
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Affiliation(s)
- Philip F Binkley
- Division of Cardiovascular Medicine, Ohio State University, Columbus, Ohio, USA.
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24
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Zhang Y, Mazgalev TN. Ventricular rate control during atrial fibrillation and AV node modifications: past, present, and future. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2004; 27:382-93. [PMID: 15009869 DOI: 10.1111/j.1540-8159.2004.00447.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia. Currently there are two broad strategic treatment options for AF: rhythm control and rate control. For rhythm control, the treatment is directed toward restoring and maintaining the sinus rhythm. For rate control, the intention is to slow ventricular rate while allowing AF to continue. In both cases anticoagulation therapy is recommended. The results of currently available clinical trials demonstrated clearly that rate control is not inferior to rhythm control. Thus, rate control is an acceptable primary therapy for many AF patients. The rate control can be achieved essentially by depressing or modifying the filtering properties of the atrioventricular (AV) node. This can be attained by medications that depress the impulse transmission within the AV node, by anatomic modification of the AV communications, as well as by autonomic manipulations that produce AV node negative dromotropic effect. We are reviewing current clinical and newer experimental modalities aimed at enhancing the lifesaving function of this remarkable nodal structure.
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Affiliation(s)
- Youhua Zhang
- Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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25
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Galuszka J, Opavský J, Lukl J, Stejskal P, Zapletalová J, Salinger J. Short-term spectral analysis of heart rate variability during supine-standing-supine test in patients with paroxysmal atrial fibrillation. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2004; 148:63-7. [PMID: 15523549 DOI: 10.5507/bp.2004.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The aim of the study was to assess the sympathovagal balance in group of 27 patients without significant structural heart disease after an attack of atrial fibrillation. The investigation was performed using spectral analysis of heart rate variability during examination under conditions of different orthostatic loads in single phases, called the supine-standing- supine test. The findings were compared with a group of healthy persons. These revealed a significantly decreased total spectral power (430.7 vs 1558.0 ms(2) supine1; 477.6 vs 1042,5 ms(2) standing; 567.5 vs 1948.5 ms(2) supine2), and spectral power of the high frequency spectral component (140.8 vs 619.3 ms(2) supine1; 96.2 vs 203.3 ms(2) standing; 186.3 vs 739.4 ms(2) supine2) in the studied group of patients in comparison with the control group.
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Affiliation(s)
- Jan Galuszka
- Ist Department of Internal Medicine, Faculty of Medicine, Palacký University Olomouc, Czech Republic.
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26
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Galuszka J, Stejskal P, Lukl J, Zapletalová J. Assessment of spectral analysis of heart rate variability in patients with history of atrial fibrillation by means of age-dependent parameters. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2002; 146:81-5. [PMID: 12572903 DOI: 10.5507/bp.2002.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Heart rate variability evaluation is a useful diagnostic tool for autonomic nervous balance assessment. The role of the autonomic nervous system in aetiology of atrial fibrillation is sometimes clear as a trigger from a patient's history, but mostly it acts as a modulating factor which is not easy to detect. The present study demonstrates results of spectral analysis of short-term heart rate variability during ortho-clinostatic tests processed by means of age-dependent parameters. An original telemetric system and a unique method for heart rate variability assessment, developed by the Faculty of Physical Culture, were applied for the first time to examine patients with the history of atrial fibrillation.
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Affiliation(s)
- Jan Galuszka
- 1st Department of Internal Medicine, Palacký University, Olomouc, Czech Republic.
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27
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Falk RH. Ventricular rate control in the elderly: is digoxin enough? THE AMERICAN JOURNAL OF GERIATRIC CARDIOLOGY 2002; 11:353-6. [PMID: 12417840 DOI: 10.1111/j.1076-7460.2002.00067.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The ventricular response in untreated patients with atrial fibrillation often exceeds 120 beats/min at rest. Digoxin can slow this rate, but its efficacy during exertion may be limited. Alternatives, or additions, to digoxin therapy include the beta blockers and diltiazem or verapamil. This review discusses the role of digoxin in relation to these other drugs, with particular reference to the elderly population.
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Affiliation(s)
- Rodney H Falk
- Section of Cardiology, Boston University School of Medicine, Boston, MA 02118, USA.
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28
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Affiliation(s)
- J C Somberg
- Rush-Presbyterian-St. Luke's Medical Center, Rush University, Chicago, IL, USA
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29
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Sticherling C, Oral H, Horrocks J, Chough SP, Baker RL, Kim MH, Wasmer K, Pelosi F, Knight BP, Michaud GF, Strickberger SA, Morady F. Effects of digoxin on acute, atrial fibrillation-induced changes in atrial refractoriness. Circulation 2000; 102:2503-8. [PMID: 11076824 DOI: 10.1161/01.cir.102.20.2503] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) shortens the atrial effective refractory period (ERP) and predisposes to further episodes of AF. The acute changes in atrial refractoriness may be related to tachycardia-induced intracellular calcium overload. The purpose of this study was to determine whether digoxin, which increases intracellular calcium, potentiates the acute effects of AF on atrial refractoriness in humans. METHODS AND RESULTS In 38 healthy adults, atrial ERP was measured at basic drive cycle lengths (BDCLs) of 350 and 500 ms after autonomic blockade. Nineteen patients had been treated with digoxin for 2 weeks. After a several-minute episode of AF, atrial ERP was measured serially at alternating BDCLs. Compared with pre-AF ERPs, the first post-AF ERPs were significantly shorter in both the digoxin and the control groups (P:<0.001). The post-AF ERP at a BDCL of 350 ms shortened to a greater degree in the digoxin group (37+/-16 ms) than in the control group (20+/-13 ms, P:<0.001); similar changes occurred at a BDCL of 500 ms. During post-AF determinations of the atrial ERP, secondary AF episodes occurred significantly more often in the digoxin group (32% versus 16%; P:<0. 04). CONCLUSIONS After a brief episode of AF, digoxin augments the shortening that occurs in atrial refractoriness and predisposes to the reinduction of AF. These effects occur in the setting of autonomic blockade and therefore are more likely to be due to the effects of digoxin on intracellular calcium than to its vagotonic effects.
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Affiliation(s)
- C Sticherling
- Division of Cardiology, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI 48109-0022, USA
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30
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Friedman HS, Win M, Hussain A, Sinha A. Effects of cardiac glycosides on atrial contractile dysfunction after short-term atrial fibrillation. Chest 2000; 118:1116-26. [PMID: 11035687 DOI: 10.1378/chest.118.4.1116] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Despite a long history of use in the treatment of paroxysmal atrial fibrillation (AF), the efficacy of cardiac glycosides has not been established. If such drugs are beneficial in this condition, the general view is that the benefit must be related to their inotropic actions. METHODS AND RESULTS To assess the effects of the rapid-acting cardiac glycoside, acetylstrophanthidin (AS), on AF and AF-induced right atrial (RA) "stunning," RA wall motion (with ultrasonic crystals), RA pressure, and peak first derivative of pressure (dp/dt) (with microtip transducers) were measured before and after 5 min of high-intensity rapid atrial stimulation (10 Hz; 10 mA; 1 ms) and after the cessation of poststimulation AF. Measurements were made in neurally intact and autonomically blockaded dogs both before and after the administration of AS (0.01 mg/kg IV bolus and 0.015 mg/kg/h IV infusion). AS prevented the post-AF reduction in RA peak dp/dt under neurally intact and autonomically blockaded conditions, and it prevented the post-AF increase in the RA end-systolic dimension and the decrease in the percentage of RA systolic shortening with autonomic blockade. AS was beneficial whether or not baseline inotropy was enhanced by AS. The duration of AF following atrial stimulation was the same before and after AS, but when compared to controls, AS treatment appeared to prolong AF. CONCLUSIONS Cardiac glycosides exert a favorable effect on AF-induced RA stunning, but this action is unrelated to its effects on the duration of AF.
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Affiliation(s)
- H S Friedman
- Department of Medicine, Long Island College Hospital and SUNY Health Science Center, Brooklyn, NY, USA.
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31
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Princi T, Delbello G, Grill V. Experimental urethane anaesthesia prevents digoxin intoxication: electrocardiographic and histological study in rabbit. Pharmacol Res 2000; 42:355-9. [PMID: 10987996 DOI: 10.1006/phrs.2000.0698] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An electrocardiographic and histological study was performed in rabbit to detect the effects of urethane (ethyl carbamate) intraperitoneal (i.p.) anaesthesia in digoxin intoxication, since it has been previously shown that this anaesthetic and digitalis glycosides exert specific peripheral effects on the cardiovascular system involving central structures of the autonomic nervous system. We observed that i.p. urethane anaesthesia prevented the onset of the electrocardiographic signs of digitalis intoxication, as well as inhibiting the appearance of histological myocardial alterations after treatment with toxic digoxin doses. On the other hand, lethal arrhythmias and severe myocardial damage were observed in animals that had not undergone preliminary urethane anaesthesia. These results indicate that the effect exerted by urethane in preventing the toxic action of digoxin is probably due to a decrease of sympathetic activity in anaesthetized animals by centrally mediated sympathetic inhibition.
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Affiliation(s)
- T Princi
- Dipartimento di Fisiologia e Patologia, Università degli Studi di Trieste, Italy
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32
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Abstract
For the most part of this the century heart failure syndrome was understood as a pump failure disorder with hemodynamic consequences stemming from the same myocardial dysfunction. In addition supply and demand theories were used to explain the nature of symptoms. As a result, therapeutic strategies were directed at correcting the abnormal hemodynamic conditions and normalizing the delivery of the much needed nutrients. Improvement of cardiac pump function with inotropic drugs and abnormal circulatory conditions with afterload and preload modifications became therapeutic goals and standards of care. However, while vasodilators and inotropic drugs immediately improved symptoms, hemodynamics and functional status, in the long term they either did not affect or worsen the natural history of heart failure. In pediatrics, this is further complicated by the lack of large scale trials addressing issues pertinent to the particularities that affect heart failure in children. In the late 1980s and 1990s heart failure has evolved into a more complex, multiple and interactive pathophysiologic disorder. Today not only the abnormal hemodynamics but also the biological disorders are pharmacologic targets. The reversal or slowing of myocardial maladaptation has become one of the most important therapeutic goals. With this end in mind therapeutic strategies may seem counterintuitive and paradoxical, such as the use of beta-blockers. This review will address the current thinking and therapeutic modalities used today in the treatment of heart failure syndrome in the adult population. We also discuss some of the issues why we think that these principles can be extrapolated to the pediatric population.
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Affiliation(s)
- M Auslender
- Pediatric Cardiology Program, New York University Medical Center, 530 First Avenue, 10016, New York, NY, USA
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33
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Affiliation(s)
- L H Opie
- Heart Research Unit, University of Cape Town, South Africa
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34
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Balaguru D, Artman M, Auslender M. Management of heart failure in children. CURRENT PROBLEMS IN PEDIATRICS 2000; 30:1-35. [PMID: 10652671 DOI: 10.1016/s0045-9380(00)80035-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- D Balaguru
- New York University Medical Center, New York, USA
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35
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Tieleman RG, Blaauw Y, Van Gelder IC, De Langen CD, de Kam PJ, Grandjean JG, Patberg KW, Bel KJ, Allessie MA, Crijns HJ. Digoxin delays recovery from tachycardia-induced electrical remodeling of the atria. Circulation 1999; 100:1836-42. [PMID: 10534473 DOI: 10.1161/01.cir.100.17.1836] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) induces electrical remodeling, which is thought to be responsible for the low success rate of antiarrhythmic treatment in AF of longer duration. Electrical remodeling seems to be related to tachycardia-induced intracellular calcium overload. Due to its vagomimetic action, digoxin is widely used to control the ventricular rate during AF, but it also increases intracellular calcium. On the basis of these characteristics, we hypothesized that digoxin would aggravate tachycardia-induced electrical remodeling. METHODS AND RESULTS We analyzed the atrial effective refractory period (AERP) at cycle lengths of 430, 300, and 200 ms during 24 hours of rapid atrio/ventricular (300/150 bpm) pacing in 7 chronically instrumented conscious goats treated with digoxin or saline. Digoxin decreased the spontaneous heart rate but had no other effects on baseline electrophysiological characteristics. In addition to a moderate increase in the rate of electrical remodeling during rapid pacing, digoxin significantly delayed the recovery from electrical remodeling after cessation of pacing (at 430, 300, and 200 ms: P=0. 001, P=0.0015, and P=0.007, respectively). This was paralleled by an increased inducibility and duration of AF during digoxin. Multivariate analysis revealed that both a short AERP and treatment with digoxin were independent predictors of inducibility (P=0.001 and P=0.03, respectively) and duration (P=0.001 for both) of AF. CONCLUSIONS Dioxin aggravates tachycardia-induced atrial electrical remodeling and delays recovery from electrical remodeling in the goat, which increases the inducibility and duration of AF.
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Affiliation(s)
- R G Tieleman
- Department of Cardiology, Thoraxcenter, University of Groningen, Netherlands
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Carmeliet E, Mubagwa K. Antiarrhythmic drugs and cardiac ion channels: mechanisms of action. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1998; 70:1-72. [PMID: 9785957 DOI: 10.1016/s0079-6107(98)00002-9] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In this review a description and an analysis are given of the interaction of antiarrhythmic drugs with their molecular target, i.e. ion channels and receptors. Our approach is based on the concept of vulnerable parameter, i.e. the electrophysiological property which plays a crucial role in the genesis of arrhythmias. To prevent or stop the arrhythmia a drug should modify the vulnerable parameter by its action on channel or receptor targets. In the first part, general aspects of the interaction between drugs channel molecules are considered. Drug binding depends on the state of the channel: rested, activated pre-open, activated open, or inactivated state. The change in channel behaviour with state is presented in the framework of the modulated-receptor hypothesis. Not only inhibition but also stimulation can be the result of drug binding. In the second part a detailed and systematic description and an analysis are given of the interaction of drugs with specific channels (Na+, Ca2+, K+, "pacemaker") and non-channel receptors. Emphasis is given to the type of state-dependent block involved (rested, activated and inactivated state block) and the change in channel kinetics. These properties vary and determine the voltage- and frequency-dependence of the change in ionic current. Finally, the question is asked as to whether the available drugs by their action on channels and receptors modify the vulnerable parameter in the desired way to stop or prevent arrhythmias.
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Affiliation(s)
- E Carmeliet
- Centre for Experimental Surgery and Anaesthesiology, University of Leuven, Belgium.
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Rich S, Seidlitz M, Dodin E, Osimani D, Judd D, Genthner D, McLaughlin V, Francis G. The short-term effects of digoxin in patients with right ventricular dysfunction from pulmonary hypertension. Chest 1998; 114:787-92. [PMID: 9743167 DOI: 10.1378/chest.114.3.787] [Citation(s) in RCA: 186] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
OBJECTIVE Studies on the effects of digoxin in patients with right ventricular failure and normal left ventricular function have not been performed. We evaluated the short-term effects of digoxin administration in patients with primary pulmonary hypertension on hemodynamics, neurohormones, and baroreceptor responsiveness. DESIGN This was a prospective study with patients serving as their own controls. SETTING University Hospital Intensive Care Unit with central monitoring. PATIENTS Seventeen patients with primary pulmonary hypertension and symptomatic heart failure were enrolled. INTERVENTIONS Following baseline hemodynamics, neurohormonal samples were drawn and the heart rate response to change in blood pressure following a challenge of phenylephrine and nitroprusside were recorded. One mg of intravenous digoxin was given and the measurements repeated after 2 hours. RESULTS Following digoxin there was a significant increase in cardiac output (3.49+/-1.2 to 3.81+/-1.2 L/min., p=0.028), a significant fall in norepinephrine (680+/-89 to 580+/-85 pg/ml, p=.013), and a significant increase in atrial natriuretic peptide (311+/-44 to 421+/-9 pg/ml, p=0.01). All of the patients had changes in heart rate and blood pressure following phenylephrine and nitroprusside challenge, but there was no significant difference in the change in heart rate response to change in blood pressure when rechallenged after digoxin treatment. CONCLUSION Digoxin produces a modest increase in cardiac output in patients with pulmonary hypertension and right ventricular failure, as well as a significant reduction in circulating norepinephrine. No detectable effects of digoxin on baroreceptor responsiveness were apparent. The use of digoxin in pulmonary hypertension is warranted.
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Affiliation(s)
- S Rich
- The Rush Heart Institute, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612-3824, USA.
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Massie BM, Abdalla I. Heart failure in patients with preserved left ventricular systolic function: do digitalis glycosides have a role? Prog Cardiovasc Dis 1998; 40:357-69. [PMID: 9449960 DOI: 10.1016/s0033-0620(98)80053-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
It is being increasingly appreciated that a substantial number of patients with congestive heart failure (CHF) have relatively preserved systolic function. Although these individuals appear to have a somewhat better prognosis than those with low ejection fractions, they experience significant symptoms and frequently require hospitalization. In these patients, CHF is often attributed to left ventricular diastolic dysfunction, but this represents a potentially misleading over-simplification. In contrast to CHF associated with left ventricular systolic dysfunction, little is known about how to treat patients with preserved systolic function. Perhaps the major point of consensus has been that the use of digitalis glycosides is inappropriate in this group. Unexpectedly, however, in the recently completed Digitalis Investigators Group trial, a subgroup of nearly 1,000 patients with radionuclide ejection fractions > or = 45% experienced a similar reduction in heart failure endpoints with digoxin therapy as patients with 25% to 44% ejection fractions. The purpose of this article is to review the diverse causes of CHF with preserved systolic function and to examine the potential mechanisms by which digoxin may be producing beneficial effect in this setting.
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Affiliation(s)
- B M Massie
- Department of Medicine, University of California, San Francisco, USA
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Affiliation(s)
- M Gheorghiade
- Department of Medicine, Northwestern University Medical School, Chicago, Ill. 60611, USA
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Flapan AD, Goodfield NE, Wright RA, Francis CM, Neilson JM. Effects of digoxin on time domain measures of heart rate variability in patients with stable chronic cardiac failure: withdrawal and comparison group studies. Int J Cardiol 1997; 59:29-36. [PMID: 9080023 DOI: 10.1016/s0167-5273(96)02893-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effect on heart rate variability of adding digoxin to a diuretic and ACE inhibitor was studied in patients with chronic stable cardiac failure. Digoxin was found to increase heart rate variability, especially those measures of heart rate variability thought to represent parasympathetic activity. The withdrawal of digoxin led to a decrease in heart rate variability to pre-treatment levels. Whilst digoxin in standard doses does not alter prognosis in chronic cardiac failure, it does have potentially beneficial neurohumoral effects. If the increase in heart rate variability, which represents beneficial neurohumoral modulation, can be divorced from the potentially detrimental effects, perhaps by using smaller doses, then there may be a role for digoxin in the treatment of chronic cardiac failure.
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Affiliation(s)
- A D Flapan
- Department of Cardiology, The Royal Infirmary, Edinburgh, UK
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Sui JL, Chan KW, Logothetis DE. Na+ activation of the muscarinic K+ channel by a G-protein-independent mechanism. J Gen Physiol 1996; 108:381-91. [PMID: 8923264 PMCID: PMC2229348 DOI: 10.1085/jgp.108.5.381] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Muscarinic potassium channels (KACh) are composed of two subunits, GIRK1 and GIRK4 (or CIR), and are directly gated by G proteins. We have identified a novel gating mechanism of KACh, independent of G-protein activation. This mechanism involved functional modification of KACh which required hydrolysis of physiological levels of intracellular ATP and was manifested by an increase in the channel mean open time. The ATP-modified channels could in turn be gated by intracellular Na+, starting at approximately 3 mM with an EC50 of approximately 40 mM. The Na(+)-gating of KACh was operative both in native atrial cells and in a heterologous system expressing recombinant channel subunits. Block of the Na+/K+ pump (e.g., by cardiac glycosides) caused significant activation of KACh in atrial cells, with a time course similar to that of Na+ accumulation and in a manner indistinguishable from that of Na(+)-mediated activation of the channel, suggesting that cardiac glycosides activated KACh by increasing intracellular Na+ levels. These results demonstrate for the first time a direct effect of cardiac glycosides on atrial myocytes involving ion channels which are critical in the regulation of cardiac rhythm.
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Affiliation(s)
- J L Sui
- Department of Physiology and Biophysics, Mount Sinai School of Medicine, City University of New York, New York 10029, USA
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van Veldhuisen DJ, de Graeff PA, Remme WJ, Lie KI. Value of digoxin in heart failure and sinus rhythm: new features of an old drug? J Am Coll Cardiol 1996; 28:813-9. [PMID: 8837553 DOI: 10.1016/s0735-1097(96)00247-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Digoxin has been a controversial drug since its introduction >200 years ago. Although its efficacy in patients with heart failure and atrial fibrillation is clear, its value in patients with heart failure and sinus rhythm has often been questioned. In the 1980s, reports of some large-scale trials indicated that digoxin, with or without vasodilators or angiotensin-converting enzyme inhibitors, reduced signs and symptoms of congestive heart failure and improved exercise tolerance. This beneficial influence was mainly found in patients with more advanced heart failure and dilated ventricles, whereas the effect in those with mild disease appeared to be less pronounced. In the last few years, new data have shown that digoxin may also have clinical value in mild heart failure, either when used in combination with other drugs or when administered alone. As neurohumoral activation has increasingly been recognized to be a contributing factor in the disease progression of chronic heart failure, the modulating effects of digoxin on neurohumoral and autonomic status have received more attention. Also, there is evidence that relatively low doses of digoxin may be at least as effective as higher doses and have a lower incidence of side effects. Further, the recognition that the use of digoxin too early after myocardial infarction may be harmful and the development of other drugs, in particular angiotensin-converting enzyme inhibitors, have obviously changed the place of digoxin in the treatment of chronic heart failure. The large-scale survival trial by the Digitalis Investigators Group (DIG), whose preliminary results have recently been presented, has shown that although digoxin has a neutral effect on total mortality during long-term treatment, it reduces the number of hospital admissions and deaths due to worsening heart failure. The potentially new features of the old drug digoxin are discussed in this review.
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Affiliation(s)
- D J van Veldhuisen
- Department of Cardiology/Thoraxcenter, University Hospital Groningen, The Netherlands
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Newton GE, Tong JH, Schofield AM, Baines AD, Floras JS, Parker JD. Digoxin reduces cardiac sympathetic activity in severe congestive heart failure. J Am Coll Cardiol 1996; 28:155-61. [PMID: 8752808 DOI: 10.1016/0735-1097(96)00120-9] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES This study evaluated the effect of digoxin on cardiac sympathetic activity in patients with congestive heart failure. BACKGROUND Digoxin favorably alters autonomic tone in heart failure. Whether it reduces cardiac sympathetic drive in the setting of heart failure is unknown. METHODS Digoxin (0.25 mg intravenously) was administered to 12 patients with severe heart failure and elevated left ventricular end-diastolic pressure (> 14 mm Hg, Group A), 5 patients with less severe heart failure who had normal left ventricular end-diastolic pressure (> 14 mm Hg, Group B) and 6 patients with normal ventricular function. Seven additional patients with heart failure were studied as a time control group. Cardiac and total body norepinephrine spillover, systemic arterial pressure, left ventricular filling pressure and peak positive first derivative of left ventricular pressure were all assessed before and 30 min after administration of digoxin. RESULTS In Group A there were no changes in hemodynamic variables or total body norepinephrine spillover after digoxin administration; however, there was a significant reduction in cardiac norepinephrine spillover (263 +/- 70 to 218 +/- 62 pmol/min, mean +/- SEM, p < 0.001). In contrast, in Group B, digoxin caused a significant increase in cardiac norepinephrine spillover that was not associated with any hemodynamic changes or a change in total body spillover. There were no hemodynamic changes or a change in total body spillover. There were no hemodynamic or spillover changes in the time control or normal ventricular function group. CONCLUSIONS Digoxin, in the absence of detectable inotropic or hemodynamic effects, caused a reduction in cardiac norepinephrine spillover in patients with heart failure who had elevated filling pressures. This finding suggests a potentially beneficial primary autonomic action of digoxin in patients with severe heart failure.
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Affiliation(s)
- G E Newton
- Department of Medicine, Division of Cardiology, Mount Sinai Hospital, Toronto, Ontario, Canada
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Brouwer J, van Veldhuisen DJ, Man in 't Veld AJ, Dunselman PH, Boomsma F, Haaksma J, Lie KI. Heart rate variability in patients with mild to moderate heart failure: effects of neurohormonal modulation by digoxin and ibopamine. The Dutch Ibopamine Multicenter Trial (DIMT) Study Group. J Am Coll Cardiol 1995; 26:983-90. [PMID: 7560628 DOI: 10.1016/0735-1097(95)00285-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVES This study assessed the effects of digoxin and ibopamine on variables of heart rate variability in relation to neurohormonal activation. BACKGROUND Analysis of heart rate variability can be used to study the autonomic dysfunction that characterizes chronic heart failure. In the Dutch Ibopamine Multicenter Trial, patients with heart failure were found to have increased neurohormonal activation with placebo therapy but not with digoxin and ibopamine therapy. METHODS We studied 59 patients with mild to moderate heart failure (mean [+/- SEM] age 60 +/- 1 years, mean ejection fraction 0.30 +/- 0.01). Patients were randomized to double-blind treatment with digoxin (0.25 mg [n = 22]), ibopamine (100 mg three times a day [n = 19]) or placebo (n = 18); background therapy consisted of furosemide (up to 80 mg). RESULTS After 3 months, plasma norepinephrine levels had increased with placebo, whereas they decreased with digoxin (+31 vs. -60 pg/ml, respectively, p < 0.01). With ibopamine, nonsignificant decrease was observed (-27 pg/ml, p = 0.10). All variables of heart rate variability showed a deterioration in the placebo group. With digoxin, the percent differences between successive RR intervals > 50 ms (pNN50) increased (+ 1.7 +/- 0.9%, p < 0.01), along with absolute and normalized high frequency power (+ 40 +/- 33 ms2, p < 0.05 and + 2.4 +/- 1.7%, p < 0.01, respectively). These changes were observed during daytime hours only and were most pronounced in patients with the most impaired baseline heart rate variability. With ibopamine, nonsignificant trends similar to the changes with digoxin were observed. CONCLUSIONS In patients with early stages of heart failure, digoxin may prevent a progressive deterioration in heart rate variability, whereas ibopamine does not show statistically significant effects. The changes in heart rate variability with digoxin parallel an observed decrease in neurohormonal activation. Digoxin apparently enhances cardiac vagal tone in the setting of neuroendocrine activation.
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Affiliation(s)
- J Brouwer
- Department of Cardiology, Thoraxcenter, University Hospital, Groningen
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Lyon X, Schutz Y, Buclin T, Jéquier E, Dériaz O. Inhibition of Na(+)-K(+)-ATPase by digoxin and its relation with energy expenditure and nutrient oxidation rate. THE AMERICAN JOURNAL OF PHYSIOLOGY 1995; 268:E1051-6. [PMID: 7611378 DOI: 10.1152/ajpendo.1995.268.6.e1051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This study investigates the effects of digoxin, an inhibitor of the Na+ pump (Na(+)-K(+)-ATPase), on resting metabolic rate (RMR), respiratory quotient (RQ), and nutrient oxidation rate. Twelve healthy male subjects followed a double-blind protocol design and received either 1 mg/day digoxin or a placebo 2 days before indirect calorimetry measurements. Digoxin induced a 0.22 +/- 0.07 kJ/min or 3.8 +/- 1.5% (mean +/- SE, P = 0.01) decrease in RMR and a 0.40 +/- 0.13 kJ/min (P = 0.01) decrease in fat oxidation rate, whereas carbohydrate and protein oxidation rates did not change significantly. A dose-response relationship between serum digoxin and RQ was observed. These results suggest that digoxin reduces not only RMR but also fat oxidation rate by mechanisms that remain to be elucidated. Because a linkage and an association between genes coding the Na(+)-K(+)-ATPase and the RQ have been previously observed, the present demonstration of an effect of Na(+)-K(+)-ATPase inhibition on fat oxidation rate strengthens the concept that the activity of this enzyme may play a role in body weight regulation.
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Affiliation(s)
- X Lyon
- Institute of Physiology, Faculty of Medicine, University of Lausanne, Switzerland
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Xu J, Hurt CM, Pelleg A. Digoxin-induced ventricular arrhythmias in the guinea pig heart in vivo: evidence for a role of endogenous catecholamines in the genesis of delayed afterdepolarizations and triggered activity. Heart Vessels 1995; 10:119-27. [PMID: 7673081 DOI: 10.1007/bf01744478] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The mechanisms of digoxin-induced ventricular arrhythmias were studied in vivo using a novel experimental model. Anesthetized guinea pigs were instrumented with custom-made electrode catheters which enabled the monitoring and recording of right atrial, right ventricular, and His bundle electrograms, midmyocardial monophasic action potentials (MAP), and systemic arterial blood pressure. Intravenous digoxin induced ventricular arrhythmias ranging from ventricular premature contractions (VPCs) to ventricular fibrillation (VF). These were associated with delayed afterdepolarizations (DADs) observed on the MAP recordings. The severity of the arrhythmias depended on the dose of digoxin. Short bursts of ventricular pacing neither terminated nor suppressed episodes of ventricular tachycardias (VTs). A direct relationship existed between the paced ventricular cycle length and the coupling interval between the last paced beat and the first ectopic beat (r = 0.913, P < 0.001, n = 10) and between the amplitude of the DADs and the pacing rate (r = 0.972, P < 0.05, n = 7). The increased contractility (LV dp/dt) and heart rate evoked by isoproterenol (0.1 microgram/kg) did not induce DADs in the absence of digoxin. Verapamil terminated the digoxin-induced VTs in 15 of 16 animals and abolished the associated DADs in 7 of 7 animals. Adenosine terminated the VTs in 15 of 19 animals and abolished the DADs in 8 of 10 animals. Digoxin induced VT in only 1 of 6 animals treated with reserpine (5 + 5 mg/kg) 24 and 48h prior to experimentation. However, subsequent intravenous isoproterenol (0.2 micrograms/kg) induced VT and DADs, both of which were abolished by verapamil, in all 6 animals.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Xu
- Likoff Cardiovascular Institute, Medical College of Pennsylvania, Philadelphia, USA
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Affiliation(s)
- L H Opie
- University of Cape Town, Ischemic Heart Disease Research Unit, South Africa
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48
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Sarter BH, Marchlinski FE. Redefining the role of digoxin in the treatment of atrial fibrillation. Am J Cardiol 1992; 69:71G-78G; discussion 78G-81G. [PMID: 1352657 DOI: 10.1016/0002-9149(92)91256-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Atrial fibrillation (AF) encompasses a variety of discrete clinical syndromes, including paroxysmal, chronic, acute, and postoperative. Digoxin, long considered the mainstay of therapy for rate control in all types of AF, appears to have only modest electrophysiologic effects, which are mediated primarily by the autonomic nervous system. Digoxin has less potency than the calcium antagonists or beta-blocking drugs with respect to atrioventricular nodal blockade. Although less potent than calcium antagonists or beta-blocking drugs on the atrioventricular node, digoxin provides positive inotropic support, whereas the other 2 agents can suppress left ventricular function. Thus, digoxin is the agent of choice in patients with AF in the setting of significant left ventricular dysfunction. However, in the absence of left ventricular dysfunction, digoxin should be considered second-line therapy for the treatment of all AF syndromes.
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Affiliation(s)
- B H Sarter
- Clinical Electrophysiology Laboratory, Hospital of the University of Pennsylvania, Philadelphia 19104
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Affiliation(s)
- M Gheorghiade
- Heart and Vascular Institute, Henry Ford Hospital, Detroit, MI 48202
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