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Rind F, Zhao S, Haring C, Kang SY, Agrawal A, Ozer E, Old MO, Carrau RL, Seim NB. Body Mass Index (BMI) Related Morbidity with Thyroid Surgery. Laryngoscope 2023; 133:2823-2830. [PMID: 37265205 DOI: 10.1002/lary.30789] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/19/2023] [Accepted: 05/10/2023] [Indexed: 06/03/2023]
Abstract
OBJECTIVES The increase in incidence of thyroid cancer correlates with strict increases in body mass index (BMI) and obesity in the United States. Thyroid hormone dysregulation has been shown to precipitate circulatory volume, peripheral resistance, cardiac rhythm, and even cardiac muscle health. Theoretically, thyroid surgery could precipitate injury to the cardiopulmonary system. METHODS The American College of Surgery National Quality Improvement Program database was queried for thyroidectomy cases in the 2007-2020 Participant User files. Continuous and categorical associations between BMI and cardiopulmonary complications were investigated as reported in the database. RESULTS The query resulted 186,095 cases of thyroidectomy procedures in which the mean age was 51.3 years and sample was 79.3% female. No correlation was evident in univariate and multivariate analyses between BMI and the incidence of postoperative stroke or myocardial infarction. The incidence of complications was extremely low. However, risk of deep venous thrombosis correlated with BMI in the categorical, univariate, and multivariate (OR 1.036, CI 1.014-1.057, p < 0.01) regression analysis. Additionally, increased BMI was associated with increased risk of pulmonary embolism (PE) (OR 1.050 (1.030, 1.069), p < 0.01), re-intubation (OR 1.012 (1.002, 1.023), p = 0.02), and prolonged intubation (OR 1.031 (1.017, 1.045), p < 0.01). CONCLUSION Despite the rarity of cardiopulmonary complications during thyroid surgery, patients with very high BMI carry a significant risk of deep venous thrombosis, PE, and prolonged intubation. LEVEL OF EVIDENCE 3 Laryngoscope, 133:2823-2830, 2023.
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Affiliation(s)
- Fahad Rind
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, Ohio, USA
| | - Songzhu Zhao
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Catherine Haring
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, Ohio, USA
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Stephen Y Kang
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, Ohio, USA
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Amit Agrawal
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, Ohio, USA
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Enver Ozer
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, Ohio, USA
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Matthew O Old
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, Ohio, USA
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Ricardo L Carrau
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, Ohio, USA
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Nolan B Seim
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, Ohio, USA
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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Müller P, Leow MKS, Dietrich JW. Minor perturbations of thyroid homeostasis and major cardiovascular endpoints—Physiological mechanisms and clinical evidence. Front Cardiovasc Med 2022; 9:942971. [PMID: 36046184 PMCID: PMC9420854 DOI: 10.3389/fcvm.2022.942971] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/22/2022] [Indexed: 11/13/2022] Open
Abstract
It is well established that thyroid dysfunction is linked to an increased risk of cardiovascular morbidity and mortality. The pleiotropic action of thyroid hormones strongly impacts the cardiovascular system and affects both the generation of the normal heart rhythm and arrhythmia. A meta-analysis of published evidence suggests a positive association of FT4 concentration with major adverse cardiovascular end points (MACE), but this association only partially extends to TSH. The risk for cardiovascular death is increased in both subclinical hypothyroidism and subclinical thyrotoxicosis. Several published studies found associations of TSH and FT4 concentrations, respectively, with major cardiovascular endpoints. Both reduced and elevated TSH concentrations predict the cardiovascular risk, and this association extends to TSH gradients within the reference range. Likewise, increased FT4 concentrations, but high-normal FT4 within its reference range as well, herald a poor outcome. These observations translate to a monotonic and sensitive effect of FT4 and a U-shaped relationship between TSH and cardiovascular risk. Up to now, the pathophysiological mechanism of this complex pattern of association is poorly understood. Integrating the available evidence suggests a dual etiology of elevated FT4 concentration, comprising both ensuing primary hypothyroidism and a raised set point of thyroid function, e. g. in the context of psychiatric disease, chronic stress and type 2 allostatic load. Addressing the association between thyroid homeostasis and cardiovascular diseases from a systems perspective could pave the way to new directions of research and a more personalized approach to the treatment of patients with cardiovascular risk.
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Affiliation(s)
- Patrick Müller
- Department for Electrophysiology, Medical Hospital I, Klinikum Vest, Recklinghausen, NRW, Germany
| | - Melvin Khee-Shing Leow
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (ASTAR), Singapore, Singapore
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore, Singapore
- Metabolic Disorders Research Programme, Lee Kong Chian School of Medicine, Singapore, Singapore
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore, Singapore
| | - Johannes W. Dietrich
- Diabetes, Endocrinology and Metabolism Section, Department of Internal Medicine I, St. Josef Hospital, Ruhr University Bochum, Bochum, NRW, Germany
- Diabetes Centre Bochum/Hattingen, St. Elisabeth-Hospital Blankenstein, Hattingen, NRW, Germany
- Centre for Rare Endocrine Diseases, Ruhr Centre for Rare Diseases (CeSER), Ruhr University Bochum and Witten/Herdecke University, Bochum, NRW, Germany
- Centre for Diabetes Technology, Catholic Hospitals Bochum, Ruhr University Bochum, Bochum, NRW, Germany
- *Correspondence: Johannes W. Dietrich
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Aguilar M, Rose RA, Takawale A, Nattel S, Reilly S. New aspects of endocrine control of atrial fibrillation and possibilities for clinical translation. Cardiovasc Res 2021; 117:1645-1661. [PMID: 33723575 PMCID: PMC8208746 DOI: 10.1093/cvr/cvab080] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/25/2021] [Accepted: 03/11/2021] [Indexed: 12/20/2022] Open
Abstract
Hormones are potent endo-, para-, and autocrine endogenous regulators of the function of multiple organs, including the heart. Endocrine dysfunction promotes a number of cardiovascular diseases, including atrial fibrillation (AF). While the heart is a target for endocrine regulation, it is also an active endocrine organ itself, secreting a number of important bioactive hormones that convey significant endocrine effects, but also through para-/autocrine actions, actively participate in cardiac self-regulation. The hormones regulating heart-function work in concert to support myocardial performance. AF is a serious clinical problem associated with increased morbidity and mortality, mainly due to stroke and heart failure. Current therapies for AF remain inadequate. AF is characterized by altered atrial function and structure, including electrical and profibrotic remodelling in the atria and ventricles, which facilitates AF progression and hampers its treatment. Although features of this remodelling are well-established and its mechanisms are partly understood, important pathways pertinent to AF arrhythmogenesis are still unidentified. The discovery of these missing pathways has the potential to lead to therapeutic breakthroughs. Endocrine dysfunction is well-recognized to lead to AF. In this review, we discuss endocrine and cardiocrine signalling systems that directly, or as a consequence of an underlying cardiac pathology, contribute to AF pathogenesis. More specifically, we consider the roles of products from the hypothalamic-pituitary axis, the adrenal glands, adipose tissue, the renin–angiotensin system, atrial cardiomyocytes, and the thyroid gland in controlling atrial electrical and structural properties. The influence of endocrine/paracrine dysfunction on AF risk and mechanisms is evaluated and discussed. We focus on the most recent findings and reflect on the potential of translating them into clinical application.
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Affiliation(s)
- Martin Aguilar
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, QC, Canada.,Department of Pharmacology and Physiology/Institute of Biomedical Engineering, Université de Montréal, Montréal, QC, Canada
| | - Robert A Rose
- Department of Cardiac Sciences, Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, Health Research Innovation Center, University of Calgary, AB, Canada
| | - Abhijit Takawale
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, QC, Canada.,Department of Pharmacology and Physiology/Institute of Biomedical Engineering, Université de Montréal, Montréal, QC, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Stanley Nattel
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada.,Faculty of Medicine, Department of Pharmacology and Physiology, and Research Centre, Montreal Heart Institute and University of Montreal, Montreal, QC, Canada.,Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Germany.,IHU LIRYC and Fondation Bordeaux Université, Bordeaux, France
| | - Svetlana Reilly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
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Subramonian D, Wu YJ, Amed S, Sanatani S. Hyperthyroidism With Atrial Fibrillation in Children: A Case Report and Review of the Literature. Front Endocrinol (Lausanne) 2021; 12:689497. [PMID: 34616360 PMCID: PMC8488087 DOI: 10.3389/fendo.2021.689497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/23/2021] [Indexed: 12/17/2022] Open
Abstract
Atrial fibrillation is exceedingly rare in children with structurally and functionally normal hearts. We present a novel case of a 15-year-old female with known hyperthyroidism who subsequently developed atrial fibrillation. She had been suffering from fatigue, heat intolerance and myalgias for 6 months. Her initial TSH was 0.01mU/L, and free T4 was 75.4 pmol/L, with a free T3 of >30.8 pmol/L. An electrocardiogram showed atrial fibrillation with a ventricular rate of 141 beats per minute. An echocardiogram demonstrated an enlarged left atrium and ventricle, with mild mitral regurgitation. She was treated with methimazole and underwent synchronized cardioversion. She subsequently returned to a euthyroid state and remained in normal sinus rhythm. In this case, we discuss the physiologic and arrhythmogenic properties of thyroid hormone, with a summary of the existing literature on atrial fibrillation in hyperthyroidism in children. Current guidelines for treatment of atrial fibrillation are also outlined.
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Affiliation(s)
- Deepa Subramonian
- Division of Pediatric Cardiology, University of British Columbia, Vancouver, BC, Canada
| | - Yuwei Juliana Wu
- Division of Pediatric Cardiology, University of British Columbia, Vancouver, BC, Canada
| | - Shazhan Amed
- Division of Pediatric Endocrinology, University of British Columbia, Vancouver, BC, Canada
| | - Shubhayan Sanatani
- Division of Pediatric Cardiology, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Shubhayan Sanatani,
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5
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Rivington J, Twohig P. Quantifying Risk Factors for Atrial Fibrillation: Retrospective Review of a Large Electronic Patient Database. J Atr Fibrillation 2020; 13:2365. [PMID: 34950310 DOI: 10.4022/jafib.2365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/14/2020] [Accepted: 07/28/2020] [Indexed: 11/10/2022]
Abstract
Background Despite the numerous comorbidities associated with atrial fibrillation (AF), the relative risk has been varying and not well-documented. Aim To quantify the risk of diseases associated with AF. Methods Population-based retrospective analysis in IBM Explorys (1999-2019), an electronic database with over 63 million patients in the United States. Odds ratios were calculated between AF and other diseases. AF patients were also stratified by age, gender, and race to assess trends of AF in different demographic groups. Results 1,812,620 patients had AF in the database. Congestive heart failure had the highest association with AF (OR 42.95). Cardiomyopathy, coronary artery disease, hypertension, and myocardial infarction all had odds greater than 15. Anemia of chronic disease and chronic kidney disease had odds greater than 18, the highest for chronic inflammatory conditions. Other conditions commonly associated with AF were found to have odds less than 8, including hyperthyroidism, alcohol use, and sleep apnea. Helicobacter pylori infection had the lowest odds at 1.98. Conclusions Epidemiologic information could be integrated with current clinical algorithms to more rapidly identify patients at risk of AF.
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Affiliation(s)
- Jaclyn Rivington
- Department of Cardiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Patrick Twohig
- Department of Gastroenterology & Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
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6
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Third degree atrioventricular block as a rare complication of Graves' thyrotoxicosis. COR ET VASA 2019. [DOI: 10.33678/cor.2019.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Omidi N, Khorgami M, Tajrishi FZ, Seyedhoseinpour A, Pasbakhsh P. The Role of Thyroid Diseases and their Medications in Cardiovascular Disorders: A Review of the Literature. Curr Cardiol Rev 2019; 16:103-116. [PMID: 31593532 PMCID: PMC7460701 DOI: 10.2174/1573403x15666191008111238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/26/2019] [Accepted: 08/29/2019] [Indexed: 12/14/2022] Open
Abstract
The association between thyroid disease and cardiovascular manifestations is significant and undeniable. Previous studies have explained several aspects of the effects of thyroid hormone on the heart and cardiovascular system. Accordingly, both hyper and hypothyroidism can cause important alterations in cardiac rhythm, output and contractility as well as vascular resistance and blood pressure. Since treating the thyroid abnormality, especially in its initial stages, could lead to a significant improvement in most of its resultant cardiovascular disturbances, early suspicion and recognition of thyroid dysfunction, is necessary in patients with cardiovascular manifestations. In this in-depth review, we discuss the physiological roles as well as the effects of abnormal levels of thyroid hormones on the cardiovascular system. We also review the effects of the medications used for the treatment of hyper and hypothyroidism on cardiac function. In the end, we discuss the association between thyroid function and amiodarone, an effective and frequently-used antiarrhythmic drug, because of its well-known effects on the thyroid.
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Affiliation(s)
- Negar Omidi
- Cardiac Primary Prevention Research Center, Tehran Heart Center and Department of Cardiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammadrafie Khorgami
- Rajaie Heart Center and Department of Pediatric Cardiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Farbod Z Tajrishi
- School of Medicine, Babol University of Medical Sciences, Babol, Iran
| | | | - Parichehr Pasbakhsh
- Department of Anatomical Sciences, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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8
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Minerath RA, Dewey CM, Hall DD, Grueter CE. Regulation of cardiac transcription by thyroid hormone and Med13. J Mol Cell Cardiol 2019; 129:27-38. [PMID: 30769017 DOI: 10.1016/j.yjmcc.2019.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 12/19/2018] [Accepted: 01/10/2019] [Indexed: 12/15/2022]
Abstract
Thyroid hormone (TH) is a key regulator of transcriptional homeostasis in the heart. While hypothyroidism is known to result in adverse cardiac effects, the molecular mechanisms that modulate TH signaling are not completely understood. Mediator is a multiprotein complex that coordinates signal-dependent transcription factors with the basal transcriptional machinery to regulate gene expression. Mediator complex protein, Med13, represses numerous thyroid receptor (TR) response genes in the heart. Further, cardiac-specific overexpression of Med13 in mice that were treated with propylthiouracil (PTU), an inhibitor of the biosynthesis of the active TH, triiodothyronine (T3), resulted in resistance to PTU-dependent decreases in cardiac contractility. Therefore, these studies aimed to determine if Med13 is necessary for the cardiac response to hypothyroidism. Here we demonstrate that Med13 expression is induced in the hearts of mice with hypothyroidism. To elucidate the role of Med13 in regulating gene transcription in response to TH signaling in cardiac tissue, we utilized an unbiased RNA sequencing approach to define the TH-dependent alterations in gene expression in wild-type mice or those with a cardiac-specific deletion in Med13 (Med13cKO). Mice were fed a diet of PTU to induce a hypothyroid state or normal chow for either 4 or 16 weeks, and an additional group of mice on a PTU diet were treated acutely with T3 to re-establish a euthyroid state. Echocardiography revealed that wild-type mice had a decreased heart rate in response to PTU with a trend toward a reduced cardiac ejection fraction. Notably, cardiomyocyte-specific deletion of Med13 exacerbated cardiac dysfunction. Collectively, these studies reveal cardiac transcriptional pathways regulated in response to hypothyroidism and re-establishment of a euthyroid state and define molecular pathways that are regulated by Med13 in response to TH signaling.
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Affiliation(s)
- Rachel A Minerath
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; Department of Pharmacology, University of Iowa, Iowa City 52242, IA, USA
| | - Colleen M Dewey
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
| | - Duane D Hall
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
| | - Chad E Grueter
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA.
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Baladi IH, Rai AA, Ahmed SM. ECG changes in patients with primary hyperthyroidism. Pan Afr Med J 2018; 30:246. [PMID: 30627307 PMCID: PMC6307920 DOI: 10.11604/pamj.2018.30.246.12244] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 05/25/2018] [Indexed: 11/11/2022] Open
Abstract
INTRODUCTION Thyroid hormones plays key role in regulating cardiovascular system. Its imbalance leads to various electrophysiological changes in cardiovascular system. This study was done to determine the frequency of electrocardiographic (ECG) changes in patients with primary hyperthyroidism. METHODS It was a descriptive cross-sectional study conducted in the Department of Medicine, Medical Unit III, Ward-7, Jinnah Postgraduate Medical Centre, Karachi, from October 2013 to April 2014. A total of 103 patients newly diagnosed with primary hyperthyroidism were included in this study. Venous blood samples were collected for T3, T3, TSH analyzed by radioimmunoassay. ECG was performed. Outcome variables were the ECG changes i.e. sinus tachycardia and atrial fibrillation. RESULTS The average age of the patients was 30.09±5.57 years (95%CI: 29 to 31.18). Out of 103 cases, 19 (18.45%) were male and 84 (81.55%) were female. Sinus tachycardia was observed in 60.19% (62/103) patients whereas atrial fibrillation was found in 11.65 (12/103) of cases. CONCLUSION In this study frequency of electrocardiographic changes in term of sinus tachycardia was high. This report has emphasized the importance of thyrotoxicosis as a cause of cardiac morbidity and mortality in patients with thyrotoxicosis. These cardiac complications are readily reversible if timely optimal treatment is offered.
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Affiliation(s)
- Ishtiaque Hussain Baladi
- Department of Medicine, Medical Unit III, Ward 7, Jinnah Postgraduate Medical Centre, Karachi, Pakistan
| | - Ayesha Aslam Rai
- Department of Medicine, Medical Unit III, Ward 7, Jinnah Postgraduate Medical Centre, Karachi, Pakistan
| | - Syed Masroor Ahmed
- Department of Medicine, Medical Unit III, Ward 7, Jinnah Postgraduate Medical Centre, Karachi, Pakistan
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El-Harasis MA, DeSimone CV, Stan MN, McLeod CJ, Noseworthy PA. Graves' disease–induced complete heart block and asystole. HeartRhythm Case Rep 2018; 4:105-108. [PMID: 29707485 PMCID: PMC5918183 DOI: 10.1016/j.hrcr.2017.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
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11
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Dysthyroidism and Chronic Heart Failure: Pathophysiological Mechanisms and Therapeutic Approaches. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1067:239-253. [PMID: 29235066 DOI: 10.1007/5584_2017_132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Among comorbidity in chronic heart failure (CHF), dysthyroidism represents a relevant problem especially in the ageing CHF patients worldwide. Thyroid greatly affects many cardiovascular activities and its dysfunction may worsen a CHF condition. In particular, hypothyroidism has a relative high prevalence in patients with heart failure and it plays a key role in influencing CHF onset, progression and prognosis. Hyperthyroidism, is less frequent in this clinical context but it necessitates of immediate treatment because of its negative effects on cardiovascular balance. Also, it must be considered that dysthyroism may also be iatrogenic and the main responsible drug is Amiodarone.Based on the best available evidence and our cumulative clinical experience, this manuscript analyzes the prevalence, the pathophysiology and the prognostic impact of thyroid disorders in chronic heart failure.
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12
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Topaloglu S, Topaloglu OY, Ozdemir O, Soylu M, Demir AD, Korkmaz S. Hyperthyroidism and Complete Atrioventricular Block. Angiology 2016; 56:217-20. [PMID: 15793611 DOI: 10.1177/000331970505600212] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although cardiovascular manifestations in thyroid disorders are frequently encountered in clinical practice, atrioventricular (AV) conduction disorders, especially in hyperthyroidism, are rare. There are some proposed mechanisms for AV blocks in hyperthyroidism but the exact mechanism is still unknown. The authors report 2 cases with thyroid function disorders and complete AV block, and the electrophysiologic characteristics of these 2 patients, and they review and speculate on similar reported cases.
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Affiliation(s)
- Serkan Topaloglu
- Turkiye Yüksek Ihtisas Hospital, Cardiology Clinics, Ankara, Turkey.
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13
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Wasson S, Reddy HK, Dohrmann ML. Current Perspectives of Electrical Remodeling and Its Therapeutic Implications. J Cardiovasc Pharmacol Ther 2016; 9:129-44. [PMID: 15309249 DOI: 10.1177/107424840400900208] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Electrical remodeling involves alterations in the electrophysiologic milieu of myocardium in various disease states, such as ventricular hypertrophy, heart failure, atrial tachyarrhythmias, myocardial ischemia, and infarction that are associated with cardiac arrhythmias. Although research in this area dates back to early part of the 19th century, we still lack the exact knowledge of ionic remodeling, the role of various genes and channel proteins, and their relevance for the newer antiarrhythmic therapies. Structural remodeling may also have an impact on the electrical remodeling process, although differences in both structural and electrical remodeling are associated with different disease states. Various electrophysiologic, cellular, and structural alterations, including anisotropic conduction, increased intracellular calcium levels, and gap junction remodeling predispose to increased dispersion of action potential duration and refractoriness. This constitutes a favorable substrate for early and late afterdepolarizations and reentrant arrhythmias. Studying the role of ionic remodeling in the initiation and propagation of cardiac arrhythmias has significant relevance for developing newer antiarrhythmic therapies, for identifying patients at risk of developing fatal arrhythmias, and for implementing effective preventive measures. Further research is required to understand the specific effects of individual ion channel remodeling, to understand the signal transduction mechanisms, and to address whether detrimental effects of electrical remodeling can be altered.
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Affiliation(s)
- Sanjeev Wasson
- Division of Cardiology, University of Missouri Hospital, Columbia, Missouri 65212, USA
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14
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Drake KJ, Shotwell MS, Wikswo JP, Sidorov VY. Glutamine and glutamate limit the shortening of action potential duration in anoxia-challenged rabbit hearts. Physiol Rep 2015; 3:3/9/e12535. [PMID: 26333831 PMCID: PMC4600381 DOI: 10.14814/phy2.12535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In clinical conditions, amino acid supplementation is applied to improve contractile function, minimize ischemia/reperfusion injury, and facilitate postoperative recovery. It has been shown that glutamine enhances myocardial ATP/APD (action potential duration) and glutathione/oxidized glutathione ratios, and can increase hexosamine biosynthesis pathway flux, which is believed to play a role in cardioprotection. Here, we studied the effect of glutamine and glutamate on electrical activity in Langendorff-perfused rabbit hearts. The hearts were supplied by Tyrode's media with or without 2.5 mmol/L glutamine and 150 μmol/L glutamate, and exposed to two 6-min anoxias with 20-min recovery in between. Change in APD was detected using a monophasic action potential probe. A nonlinear mixed-effects regression technique was used to evaluate the effect of amino acids on APD over the experiment. Typically, the dynamic of APD change encompasses three phases: short transient increase (more prominent in the first episode), slow decrease, and fast increase (starting with the beginning of recovery). The effect of both anoxic challenge and glutamine/glutamate was cumulative, being more pronounced in the second anoxia. The amino acids' protective effect became largest by the end of anoxia – 20.0% (18.9, 95% CI: [2.6 ms, 35.1 ms]), during the first anoxia and 36.6% (27.1, 95% CI: [7.7 ms, 46.6 ms]), during the second. Following the second anoxia, APD difference between control and supplemented hearts progressively increased, attaining 10.8% (13.6, 95% CI: [4.1 ms, 23.1 ms]) at the experiments' end. Our data reveal APD stabilizing and suggest an antiarrhythmic capacity of amino acid supplementation in anoxic/ischemic conditions.
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Affiliation(s)
- Kenneth J Drake
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee
| | - Matthew S Shotwell
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee
| | - John P Wikswo
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Veniamin Y Sidorov
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
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Kobayashi H, Haketa A, Abe M, Tahira K, Hatanaka Y, Tanaka S, Ueno T, Soma M. Unusual Manifestation of Graves' Disease: Ventricular Fibrillation. Eur Thyroid J 2015; 4:207-12. [PMID: 26558239 PMCID: PMC4637814 DOI: 10.1159/000437225] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/25/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND It is well known that thyrotoxicosis causes rhythm disorders including sinus tachycardia, atrial fibrillation, and atrial flutter. Atrial fibrillation is the most common arrhythmia in thyrotoxicosis, occurring in 5-15% of patients over 60 years of age, whereas ventricular arrhythmia is an unusual manifestation. CASE REPORT An 18-year-old Japanese woman was admitted to our emergency department because of loss of consciousness caused by ventricular fibrillation. She had been diagnosed with Graves' disease only 5 days earlier and had no other past medical history. Blood examination showed no obvious abnormality except thyrotoxicosis, and coronary angiography revealed patent coronary arteries. She was diagnosed with thyroid storm due to Graves' disease and is currently healthy during outpatient follow-up. CONCLUSION This case highlights that thyrotoxicosis can, albeit extremely rarely, cause ventricular fibrillation even in the absence of hypokalemia or underlying cardiovascular disease.
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Affiliation(s)
| | - Akira Haketa
- *Akira Haketa, MD, Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, 30-1 Oyaguchi Kami-chou, Itabashi-ku, Tokyo 173-8610 (Japan), E-Mail
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Arrhythmia and thyroid dysfunction. Herz 2014; 40 Suppl 2:101-9. [DOI: 10.1007/s00059-014-4123-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/20/2014] [Accepted: 05/27/2014] [Indexed: 10/25/2022]
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Venditti P, Di Stefano L, Di Meo S. Vitamin E management of oxidative damage-linked dysfunctions of hyperthyroid tissues. Cell Mol Life Sci 2013; 70:3125-44. [PMID: 23255045 PMCID: PMC11114018 DOI: 10.1007/s00018-012-1217-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 11/15/2012] [Accepted: 11/19/2012] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Thyroid hormones affect growth, development, and metabolism of vertebrates, and are considered the major regulators of their homeostasis. On the other hand, elevated circulating levels of thyroid hormones are associated with modifications in the whole organism (weight loss and increased metabolism and temperature) and in several body regions. Indeed, tachycardia, atrial arrhythmias, heart failure, muscle weakness and wasting, bone mass loss, and hepatobiliary complications are commonly found in hyperthyroid animals and humans. RESULTS Most thyroid hormone actions result from influences on transcription of T3-responsive genes, which are mediated through nuclear receptors. However, there is significant evidence that tissue oxidative stress underlies some dysfunctions produced by hyperthyroidism. DISCUSSION During the last decades, increasing interest has been turned to the use of antioxidants as therapeutic agents in various diseases and pathophysiological disorders believed to be mediated by oxidative stress. In particular, because elevated circulating levels of thyroid hormones are associated with tissue oxidative injury, more attention has been paid to explore the application of antioxidants as therapeutic agents in thyroid related disorders. CONCLUSIONS At present, vitamin E is among the most commonly consumed dietary supplements due to the belief that it, as an antioxidant, may attenuate morbidity and mortality. This is due to the results of numerous scientific studies, which demonstrate that vitamin E has a primary function to destroy peroxyl radicals, thus protecting polyunsaturated fatty acids biological membranes from oxidative damage. However, results are also available indicating that protective vitamin E effects against oxidative damage can be obtained even through different mechanisms.
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Affiliation(s)
- Paola Venditti
- Dipartimento delle Scienze Biologiche, Sezione di Fisiologia, Università di Napoli Federico II, Via Mezzocannone 8, 80134 Naples, Italy.
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Ozaydin M, Kutlucan A, Turker Y, Koroglu B, Arslan A, Uysal BA, Erdogan D, Varol E, Dogan A. Association of inflammation with atrial fibrillation in hyperthyroidism. J Geriatr Cardiol 2013; 9:344-8. [PMID: 23341838 PMCID: PMC3545250 DOI: 10.3724/sp.j.1263.2012.06251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/16/2012] [Accepted: 10/19/2012] [Indexed: 01/08/2023] Open
Abstract
Objectives The aim of this study was to evaluate the relationship between inflammation and development of atrial fibrillation (AF) in patients with hyperthyroidism. Methods A total of 65 patients with newly diagnosed hyperthyroidism, 35 of whom were in sinus rhythm and 30 of whom in AF. Thirty five age- and gender-matched patients in a control group were included in the study. Factors associated with the development of AF were evaluated by multivariate regression analysis. Results Factors associated with AF in multivariate analysis included high sensitivity C reactive protein (HsCRP) [odds ratio (OR): 11.19; 95% confidence interval (95% CI): 1.80-69.53; P = 0.003], free T4 (OR: 8.76; 95% CI: 2.09–36.7; P = 0.003), and left atrial diameter (OR: 1.25; 95% CI: 1.06–1.47; P = 0.008). Conclusions The results of the present study suggest that HsCRP, an indicator of inflammation, free T4 and left atrial diameter are associated with the development AF in patients with hyperthyroidism.
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Affiliation(s)
- Mehmet Ozaydin
- Department of Cardiology, Suleyman Demirel University, Kurtulus Mah 122. cad. Hatice Halici apt. no: 126, 32040 Isparta, Turkey
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Ravens U. Antiarrhythmic therapy in atrial fibrillation. Pharmacol Ther 2010; 128:129-45. [DOI: 10.1016/j.pharmthera.2010.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 06/11/2010] [Indexed: 12/19/2022]
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Cini G, Carpi A, Mechanick J, Cini L, Camici M, Galetta F, Giardino R, Russo M, Iervasi G. Thyroid hormones and the cardiovascular system: Pathophysiology and interventions. Biomed Pharmacother 2009; 63:742-53. [DOI: 10.1016/j.biopha.2009.08.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 08/24/2009] [Indexed: 10/20/2022] Open
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Guntekin U, Gunes Y, Tuncer M, Simsek H, Gumrukcuoglu HA, Arslan S, Gunes A. QTc dispersion in hyperthyroidism and its association with pulmonary hypertension. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2009; 32:494-9. [PMID: 19335859 DOI: 10.1111/j.1540-8159.2009.02310.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Several studies have reported that hyperthyroidism is associated with prolonged QT interval corrected by the heart rate (QTc) and pulmonary hypertension (PHT). METHODS Forty-seven patients with newly diagnosed overt hyperthyroidism and 20 healthy people were enrolled in the study. Transthoracic echocardiography, 12-lead surface electrocardiogram, and thyroid hormone levels were studied at the time of enrollment and after achievement of euthyroid state with propylthiouracil treatment. RESULTS Baseline clinical characteristics were similar. However, heart rate (90.5+/-19.6 vs 79.2+/-13.7 bpm, P = 0.024), pulmonary artery systolic pressure (PASP) (26.0+/-12.0 vs 10.6+/-4.0 mmHg, P < 0.001), E deceleration time (DT) (191.8+/-25.6 vs 177.0+/-10.7 ms, P = 0.016), isovolumetric relaxation time (IVRT) (91.38+/-12.3 vs 79.6+/-10.5 ms, P < 0.001), and QTc dispersion (QTcD) (50.3+/-17.2 vs 38.9+/-11.6 ms, P = 0.009) were significantly higher in hyperthyroid patients compared to control group. Heart rate (to 74.1+/-13.8, P < 0.001), QTcD (to 37.3+/-10.1 ms, P < 0.001), DT (to 185.3+/-19.7 ms, P = 0.008), IVRT (to 88.6+/-10.3 ms, P = 0.056), and PASP (23.1+/-10.1 mmHg P < 0.001) were significantly decreased after achievement of euthyroid state. Although PHT was present in 16 patients before treatment only six patients still had PHT during euyhyroid state. Compared to patients with normal PASP, QTcD was significantly longer in patients with PHT (56.5+/-15.8 vs 37.9+/-12.8 mmHg P < 0.001). There were also significant correlations between QTcD and presence of PHT (r = 0.516, P < 0.001) and PASP (r = 0.401, P = 0.009). CONCLUSIONS Hyperthyroidism is a reversible cause of PHT and diastolic dysfunction. Increased QTcD observed in hyperthyroidism may be associated with PHT and diastolic dysfunction. These abnormal findings in hyperthyroidism often normalize with the achievement of euthyroid state.
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Affiliation(s)
- Unal Guntekin
- Yuzuncu Yil University, Faculty of Medicine, Cardiology Department, Van, Turkey.
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Olsson SB. Nature of cardiac arrhythmias and electrolyte disturbances. Role of potassium in atrial fibrillation. ACTA MEDICA SCANDINAVICA. SUPPLEMENTUM 2009; 647:33-7. [PMID: 6942640 DOI: 10.1111/j.0954-6820.1981.tb02636.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Atrial fibrillation is highly favoured by an accelerated atrial muscle repolarization. In hyperthyroidism, this occurs without changes in resting membrane potential level of the atrial muscle cells and without changes in the ionic composition of the cell. In patients prone to atrial fibrillation but without signs of hyperthyroidism, accelerated atrial repolarization can also be demonstrated. In such patients, a decreased atrial muscle potassium content seems responsible for the electrophysiological changes that highly favours the occurrence of atrial fibrillation.
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Abstract
Atrial fibrillation (AF) is a complex condition with several possible contributing factors. The rapid and irregular heartbeat produced by AF increases the risk of blood clot formation inside the heart. These clots may eventually become dislodged, causing embolism, stroke and other disorders. AF occurs in up to 15% of patients with hyperthyroidism compared to 4% of people in the general population and is more common in men and in patients with triiodothyronine (T3) toxicosis. The incidence of AF increases with advancing age. Also, subclinical hyperthyroidism is a risk factor associated with a 3-fold increase in development of AF. Thyrotoxicosis exerts marked influences on electrical impulse generation (chronotropic effect) and conduction (dromotropic effect). Several potential mechanisms could be invoked for the effect of thyroid hormones on AF risk, including elevation of left atrial pressure secondary to increased left ventricular mass and impaired ventricular relaxation, ischemia resulting from increased resting heart rate, and increased atrial eopic activity. Reentry has been postulated as one of the main mechanisms leading to AF. AF is more likely if effective refractory periods are short and conduction is slow. Hyperthyroidism is associated with shortening of action potential duration which may also contribute to AF.
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Abstract
The heart is a major target organ for thyroid hormone action, and marked changes occur in cardiac function in patients with hypo- or hyperthyroidism. T(3)-induced changes in cardiac function can result from direct or indirect T(3) effects. Direct effects result from T(3) action in the heart itself and are mediated by nuclear or extranuclear mechanisms. Extranuclear T(3) effects, which occur independent of nuclear T(3) receptor binding and increases in protein synthesis, influence primarily the transport of amino acids, sugars, and calcium across the cell membrane. Nuclear T(3) effects are mediated by the binding of T(3) to specific nuclear receptor proteins, which results in increased transcription of T(3)-responsive cardiac genes. The T(3) receptor is a member of the ligand-activated transcription factor family and is encoded by cellular erythroblastosis A (c-erb A) genes. T(3) also leads to an increase in the speed of diastolic relaxation, which is caused by the more efficient pumping of the calcium ATPase of the sarcoplasmic reticulum. This T(3) effect results from T(3)-induced increases in the level of the mRNA coding for the sarcoplasmic reticulum calcium ATPase protein, leading to an increased number of calcium ATPase pump units in the sarcoplasmic reticulum.
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Affiliation(s)
- George J Kahaly
- Departmrent of Medicine I, Endocrine Unit, Gutenberg-University Hospital, D-55101 Mainz, Germany
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Hynes BJ, Luck JC, Wolbrette DL, Khan M, Naccarelli GV. A review of the pharmacokinetics, electrophysiology and clinical efficacy of dronedarone. Future Cardiol 2005; 1:135-44. [DOI: 10.1517/14796678.1.2.135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The results of major clinical trials and advances in pharmacologic and nonpharmacologic therapies are continuing to alter treatment approaches for both atrial and ventricular arrhythmias. Originally developed as an antianginal medication, amiodarone serves as the most effective antiarrhythmic drug in the treatment of both atrial and life-threatening ventricular arrhythmias. However, amiodarone has complex pharmacokinetics and is associated with serious extracardiac side effects, partially due to the presence of an iodine moiety. With a better understanding of the mechanisms of arrhythmias and antiarrhythmic drugs, new antiarrhythmic agents are currently under development with the hope that they will be more effective and safer than currently available drugs. One such drug that might potentially fulfill this hope is dronedarone. This amiodarone-like compound lacks the iodine moiety, and is similar in structure and electrophysiologic mechanisms of action to amiodarone, to date no evidence of liver, thyroid or pulmonary toxicity has been reported. Three clinical trials demonstrate efficacy in suppressing recurrences of atrial fibrillation and there is also evidence of a rate-slowing benefit during atrial fibrillation/flutter. However, the ANtiarrhythmic trial with DROnedarone in Moderate-to-severe congestive heart failure Evaluating morbidity Decrease (ANDROMEDA) study, performed in patients with left ventricular dysfunction, demonstrated excess noncardiac mortality in patients treated with dronedarone. Although effective in the treatment of atrial fibrillation, the future of this novel amiodarone-like drug remains uncertain until further clarification of the excess mortality in heart failure patients is better studied.
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Affiliation(s)
- B John Hynes
- Penn State University College of Medicine, Division of Cardiology and Penn State Cardiovascular Center, MC H047, 500 University Dr Hershey, PA 17033, Pennsylvania, USA
| | - Jerry C Luck
- Penn State University College of Medicine, Division of Cardiology and Penn State Cardiovascular Center, MC H047, 500 University Dr Hershey, PA 17033, Pennsylvania, USA
| | - Deborah L Wolbrette
- Penn State University College of Medicine, Division of Cardiology and Penn State Cardiovascular Center, MC H047, 500 University Dr Hershey, PA 17033, Pennsylvania, USA
| | - Mazhar Khan
- Penn State University College of Medicine, Division of Cardiology and Penn State Cardiovascular Center, MC H047, 500 University Dr Hershey, PA 17033, Pennsylvania, USA
| | - Gerald V Naccarelli
- Penn State University College of Medicine, Division of Cardiology and Penn State Cardiovascular Center, MC H047, 500 University Dr Hershey, PA 17033, Pennsylvania, USA
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Aras D, Maden O, Ozdemir O, Aras S, Topaloglu S, Yetkin E, Demir AD, Soylu MO, Erdogan MF, Kisacik HL, Korkmaz S. Simple electrocardiographic markers for the prediction of paroxysmal atrial fibrillation in hyperthyroidism. Int J Cardiol 2005; 99:59-64. [PMID: 15721500 DOI: 10.1016/j.ijcard.2003.11.040] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2003] [Accepted: 11/14/2003] [Indexed: 11/28/2022]
Abstract
BACKGROUND Hyperthyroidism is a major cause of paroxysmal atrial fibrillation (AF). The purpose of this study was to evaluate the predictors of AF in the patients with clinical and subclinical hyperthyroidism. METHODS AND RESULTS The study population consisted of four groups: group I (57 euthyroid healthy persons), group II (33 patients with subclinical hyperthyroidism), group III (69 patients with overt hyperthyroidism) and group IV (31 patients with overt hyperthyroidism and documented paroxysmal AF). The maximum P wave duration (P maximum) in group IV (114 +/- 8 ms) was significantly higher than group I (102 +/- 7 ms, p < 0.001), group II (106 +/- 7 ms, p < 0.001) and group III (108 +/- 9 ms, p0.005). The P wave dispersion (PWD) was measured as 46 +/- 9 ms in group IV and this was significantly higher than group I (29 +/- 8 ms, p < 0.001), group II (36 +/- 9 ms, p < 0.001) and grup III (38 +/- 8 ms, p = 0.001). The P maximum and PWD were higher in the patients with subclinical hyperthyroidism compared to healthy individuals. Univariate regression analysis revealed that age, P maximum and PWD, multivariate analysis showed that P maximum and PWD were significant predictors of paroxysmal AF. A PWD value of 37.5 ms separated group IV from others with a sensitivity of 90%, specificity of 85%, and positive predictive accuracy of 77%. CONCLUSION Simply measuring P maximum and PWD values, we could identify the patients with high risk for the development of AF and these simple ECG parameters may help in clinical judgement to determine the requirement for treatment in the patients with subclinical hyperthyroidism.
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Affiliation(s)
- Dursun Aras
- Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara, Turkey.
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Hansson A, Madsen-Härdig B, Bertil Olsson S. Arrhythmia-provoking factors and symptoms at the onset of paroxysmal atrial fibrillation: a study based on interviews with 100 patients seeking hospital assistance. BMC Cardiovasc Disord 2004; 4:13. [PMID: 15291967 PMCID: PMC514544 DOI: 10.1186/1471-2261-4-13] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2004] [Accepted: 08/03/2004] [Indexed: 11/24/2022] Open
Abstract
Background Surprisingly little information on symptoms of paroxysmal atrial fibrillation is available in scientific literature. Using questionnaires, we have analyzed the symptoms associated with arrhythmia attacks. Methods One hundred randomly-selected patients with idiopathic paroxysmal atrial fibrillation filled in a structured questionnaire. Results Psychic stress was the most common factor triggering arrhythmia (54%), followed by physical exertion (42%), tiredness (41%) coffee (25%) and infections (22%). Thirty-four patients cited alcohol, 26 in the form of red wine, 16 as white wine and 26 as spirits. Among these 34, red wine and spirits produced significantly more episodes of arrhythmia than white wine (p = 0.01 and 0.005 respectively). Symptoms during arrhythmia were palpitations while exerting (88%), reduced physical ability (87%), palpitations at rest (86%), shortage of breath during exertion (70%) and anxiety (59%). Significant differences between sexes were noted regarding swollen legs (women 21%, men 6%, p = 0.027), nausea (women 36%, men 13%, p = 0.012) and anxiety (females 79%, males 51%, p = 0.014). Conclusion Psychic stress was the commonest triggering factor in hospitalized patients with paroxysmal atrial fibrillation. Red wine and spirits were more proarrhythmic than white wine. Symptoms in women in connection with attacks of arrhythmia vary somewhat from those in men.
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Affiliation(s)
- Anders Hansson
- Department of Cardiology, University Hospital, Lund, Sweden
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Wang YG, Dedkova EN, Fiening JP, Ojamaa K, Blatter LA, Lipsius SL. Acute exposure to thyroid hormone increases Na+ current and intracellular Ca2+ in cat atrial myocytes. J Physiol 2003; 546:491-9. [PMID: 12527735 PMCID: PMC2342523 DOI: 10.1113/jphysiol.2002.032847] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Whole-cell recording methods and fluorescence microscopy were used to study the effects of acute exposure to thyroid hormone (T(3)) on cat atrial myocytes. Acute exposure ( approximately 5 min) to 10 nM T(3) significantly increased tetrodotoxin (TTX)-sensitive inward Na(+) current (I(Na)) at voltages between -40 and +20 mV. At maximal I(Na) activation (-40 mV) T(3) increased peak I(Na) by 32 %. T(3) had no effect on the time course of I(Na) decay, voltage dependence of activation, inactivation, or recovery from inactivation. Comparable exposures to reverse T(3) (rT(3)) or T(4) had no effect on I(Na). L-type Ca2+ current was unaffected by acute exposure to T(3). T(3)-induced increases in I(Na) were unaffected by 50 microM nickel, a blocker of T-type Ca2+ current. T(3) significantly increased cell shortening (+62 %) and could elicit spontaneous action potentials arising from Ca2+ -mediated after-depolarizations. T(3) (but not rT(3)) significantly increased baseline intracellular Ca2+, release of Ca2+ from sarcoplasmic reticulum (SR) and caffeine (10 mM)-induced release of SR Ca2+. We conclude that acute T(3) exposure increases Na(+) influx via I(Na) and thereby stimulates reverse-mode Na(+)-Ca2+ exchange to increase intracellular Ca2+ content and release. As a result, T(3) increases contraction strength, and can initiate Ca2+ -mediated arrhythmic activity. Acute non-genomic effects of T(3) can contribute to the positive inotropy and sinus (atrial) tachycardia traditionally attributed to chronic, genomic effects of elevated thyroid hormone on atrial muscle.
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Affiliation(s)
- Yong G Wang
- Department of Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Avenue, Maywood, IL 60153, USA
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Sen L, Sakaguchi Y, Cui G. G protein modulates thyroid hormone-induced Na(+) channel activation in ventricular myocytes. Am J Physiol Heart Circ Physiol 2002; 283:H2119-29. [PMID: 12384490 DOI: 10.1152/ajpheart.00326.2002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To evaluate the effects of liothyronine (3,5,3'-triiodo-L-thyronine, T(3)) on Na(+) channel current (I(Na)) properties, I(Na) was recorded in adult guinea pig ventricular myocytes. T(3) (1 nM) acutely increased whole cell I(Na) and shifted the steady-state I(Na) inactivation curve dose dependently. When the pipette solution contained 100 microM GTP or GTPgammaS, the effect of T(3) on the whole cell I(Na) was increased two- to threefold. This effect was almost completely abolished by pertussis toxin preincubation. In the cell-attached patch, T(3) increased the open probability of single I(Na) by reducing the null probability. In the inside-out patch, T(3) effect was 10 times faster than that in whole cell and cell-attached patches while GTPgammaS was present and could be completely washed out. T(3) alone slightly increased the channel open probability by increasing the closed state to open state rate constant (k(CO)) and reducing the null probability. GTPgammaS exposure only increased the number of functional channels. T(3) and GTPgammaS synergistically enhanced the channel open probability 5.8 +/- 0.5-fold by increasing k(CO), decreasing the open state to absorbing inactivated state rate constant, and greatly reducing the null probability. These results demonstrate that T(3) acts on the cytosolic side of the membrane and acutely activates I(Na). Pertussis toxin-sensitive G protein modulation greatly magnifies the T(3) effects on the channel kinetics and null probability, thereby increasing the channel open probability.
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Affiliation(s)
- Luyi Sen
- Division of Cardiology, Department of Medicine, The David Geffen School of Medicine, 47-123 CHS, University of California-Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095-1679, USA.
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Pantos C, Mourouzis I, Delbruyère M, Malliopoulou V, Tzeis S, Cokkinos DD, Nikitas N, Carageorgiou H, Varonos D, Cokkinos D, Nisato D. Effects of dronedarone and amiodarone on plasma thyroid hormones and on the basal and postischemic performance of the isolated rat heart. Eur J Pharmacol 2002; 444:191-6. [PMID: 12063079 DOI: 10.1016/s0014-2999(02)01624-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The present study investigated the effects of dronedarone and amiodarone on plasma thyroid hormones and the possible consequences on the response of the heart to ischemia. Amiodarone (30 mg/kg/day per os) or dronedarone (30 mg/kg/day per os) were administered for 2 weeks in normal and thyroxine-treated animals (25 microg/100 g body weight od sc, for 2 weeks), while animals without amiodarone and dronedarone served as controls. Isolated rat hearts were perfused in a Langendorff mode and subjected to 20 and 30 min of zero-flow global ischemia followed by 45 min of reperfusion. Functional changes were assessed by measuring left ventricular developed pressure (LVDP) under resting conditions and in response to ischemia-reperfusion, LVDP%, as well as the severity of ischemic contracture. Amiodarone resulted in increased T4, T4/T3 and rT3, whereas dronedarone did not alter the thyroid hormone profile in normal animals. In thyroxine-treated animals, amiodarone increased T4/T3 ratio but T4, T3 and rT3 levels were not altered. Basal functional parameters and ischemic contracture did not change by amiodarone and/or dronedarone neither in normal nor in thyroxine-treated hearts. In normal hearts, postischemic functional recovery, LVDP%, was not altered by amiodarone or dronedarone administration. LVDP% was statistically higher in thyroxine-treated hearts than in normal and this beneficial effect was not abolished by amiodarone or dronedarone treatment.
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Affiliation(s)
- Constantinos Pantos
- Department of Pharmacology, University of Athens, 75 Mikras Asias Ave., 11527 Goudi, Greece.
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Komiya N, Isomoto S, Nakao K, Hayano M, Yano K. Electrophysiological abnormalities of the atrial muscle in patients with paroxysmal atrial fibrillation associated with hyperthyroidism. Clin Endocrinol (Oxf) 2002; 56:39-44. [PMID: 11849245 DOI: 10.1046/j.0300-0664.2001.01459.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Atrial fibrillation (AF) is common in patients with hyperthyroidism. Although the choice of an antiarrhythmic agent should be based on its electrophysiological effects and the electrophysiological properties of the arrhythmia in question, the atrial electrophysiological features of AF associated with hyperthyroidism are unknown. The purposes of this study are to clarify the atrial electrophysiological abnormalities of AF with hyperthyroidism, and to propose effective therapies for AF in patients with hyperthyroidism. SUBJECTS AND DESIGN This study included 117 patients who underwent electrophysiological study and were evaluated for thyroid function: 29 patients without AF or hyperthyroidism (Group I), 78 patients with lone paroxysmal AF (Group II), and 10 patients with paroxysmal AF and hyperthyroidism (Group III). The following electrophysiological parameters were assessed and measured quantitatively: (1) the incidence of abnormal right atrial electrograms during sinus rhythm, indicating areas of altered anatomy and conduction where AF is likely to develop; (2) the atrial effective refractory period (ERP); and (3) the atrial conduction delay (CD), which is induced by early atrial premature beats close to the atrial ERP and is thought to facilitate the occurrence of AF. RESULTS The incidence of abnormal right atrial electrograms during sinus rhythm was significantly higher in Group II (67.1%) than in Group I (20.0%, P < 0.001) and Group III (22.2%, P = 0.009). The atrial ERP was significantly shorter in Group III (187 +/- 7 ms) than in Group I (215 +/- 36 ms, P = 0.019) and Group II (208 +/- 28 ms, P = 0.022). The atrial CD was observed in Group III as well as in Group II. CONCLUSIONS Our data indicate that the electrophysiological features of paroxysmal AF associated with hyperthyroidism are essentially different from those of lone paroxysmal AF. In patients with paroxysmal AF and hyperthyroidism, a shortening of the refractory period in association with a facilitation of the atrial CD could be expected to increase the propensity for AF, and a pre-existent arrhythmogenic substrate might not be essential to the genesis of AF. These findings suggest that the agents that prolong the atrial ERP are effective against AF in patients with hyperthyroidism.
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Affiliation(s)
- Norihiro Komiya
- Third Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan
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Shiga T, Wakaumi M, Matsuda N, Shoda M, Hagiwara N, Sato K, Kasanuki H. Amiodarone-Induced thyroid dysfunction and ventricular tachyarrhythmias during long-term therapy in Japan. JAPANESE CIRCULATION JOURNAL 2001; 65:958-60. [PMID: 11716246 DOI: 10.1253/jcj.65.958] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In 232 Japanese patients receiving long-term amiodarone therapy for life-threatening ventricular tachyarrhythmias, hyperthyroidism and hypothyroidism developed in 29 patients (12.5%) and 25 patients (10.8%), respectively. In patients with hyperthyroidism, the recurrence of sustained ventricular tachycardia was significantly higher with thyrotoxicosis than in the euthyroid period (31% vs 3%, p<0.01). Holter monitoring showed that the average heart rate and ventricular premature complexes significantly increased with hyperthyroidism. On the other hand, there was no increase in the recurrence of ventricular tachyarrhythmia with hypothyroidism. There was no change in the dose or the plasma concentration of amiodarone or desethylamiodarone in the euthyroid period or when hyperthyroidism or hypothyroidism manifested. It is important to monitor for arrhythmia when hyperthyroidism develops during amiodarone therapy.
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Affiliation(s)
- T Shiga
- Department of Cardiology, The Heart Institute of Japan, Tokyo Women's Medical University.
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Auer J, Scheibner P, Mische T, Langsteger W, Eber O, Eber B. Subclinical hyperthyroidism as a risk factor for atrial fibrillation. Am Heart J 2001; 142:838-42. [PMID: 11685172 DOI: 10.1067/mhj.2001.119370] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVES Atrial fibrillation is a well-known manifestation of hyperthyroidism. We studied whether subclinical hyperthyroidism with low serum thyrotropin concentrations and free thyroid hormone concentrations within the normal range in clinically euthyroid persons is a risk factor for subsequent atrial fibrillation. METHODS We studied 23,638 persons. The subjects were classified according to their serum thyrotropin concentrations: group 1 comprised those with normal values of serum thyrotropin concentration (>0.4-5.0 mU/L) and free tri-iodothyronine and free thyroxine concentrations were within the normal range (22,300 subjects), group 2 comprised those with both low serum thyrotropin values (</=0.03 mU/L) and elevated free tri-iodothyronine and free thyroxine concentrations (725 subjects), and group 3 comprised those with low values of serum thyrotropin (<0.4 mU/L) and free triiodothyronine and free thyroxine concentrations were within the normal range (613 subjects). RESULTS Atrial fibrillation was present in 513 persons (2.3%) in group 1 with normal values for serum thyrotropin, 100 (13.8%) in group 2 with overt hyperthyroidism, and 78 (12.7%) in group 3 with subclinical hyperthyroidism. The prevalence of atrial fibrillation in patients with low serum thyrotropin concentrations (<0.4 mU/L) was 13.3% compared with 2.3% in patients with normal values for serum thyrotropin (P <.01). The relative risk of atrial fibrillation in subjects with low serum thyrotropin and normal free tri-iodothyronine and free thyroxine concentrations, compared with those with normal concentrations of serum thyrotropin, was 5.2 (95% CI 2.1-8.7, P <.01). CONCLUSION A low serum thyrotropin concentration is associated with a >5-fold higher likelihood for the presence of atrial fibrillation with no significant difference between subclinical and overt hyperthyroidism.
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Affiliation(s)
- J Auer
- Division of Cardiology and Intensive Care, Department of Internal Medicine II, General Hospital Wels, Wels, Austria.
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Abstract
The basic underlying mechanisms behind atrial fibrillation (AF), the most abundant therapy demanding cardiac dysrhythmia, have until recently being largely unknown. Once established, AF is not only self-perpetuating but also self-destructive, prompting rapid treatment against possible initiating mechanisms. Recent observations reveal that the ectopic beats, initiating AF, often originate in the walls of the pulmonary veins and that the deterioration of the ectopic impulse to AF may be linked to an impaired inferoposterior interatrial conduction. The underlying mechanisms behind these functional defects are still obscure. The observations has however, permitted evaluation of new types of treatment, directly interfering with the newly verified findings.
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Affiliation(s)
- S B Olsson
- Department of Cardiology, University Hospital, Lund, Sweden
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41
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Colzani RM, Emdin M, Conforti F, Passino C, Scarlattini M, Iervasi G. Hyperthyroidism is associated with lengthening of ventricular repolarization. Clin Endocrinol (Oxf) 2001; 55:27-32. [PMID: 11453949 DOI: 10.1046/j.1365-2265.2001.01295.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Lengthened ventricular repolarization, as assessed by the QT interval on electrocardiogram (ECG), can predispose to an increased risk of cardiac dysrhythmias; no data are available on QT corrected for heart rate (QTc) in hyperthyroidism in vivo. DESIGN QT and RR intervals from 24 h ambulatory ECG Holter recording were measured in patients with hyperthyroidism and again following pharmacological achievement of stable euthyroidism for at least 2 months. PATIENTS We enrolled a total of 16 hyperthyroid patients with Graves' disease, six males and 10 females (mean age 47 +/- 4 years, mean +/- SEM); 13 healthy age- and sex-matched subjects were utilized as a control group. MEASUREMENTS The QT analysis was carried out by a computerized algorithm (QTc was corrected by the heart rate by Bazett's formula). Serum total T4, total T3, free T4, free T3 and TSH concentrations were measured by a fully automated immunoenzymometric assay; plasma norepinephrine by automatized high-pressure liquid chromatography, potassium and chloride by a potentiometric method, magnesium and calcium by a colourimetric method. RESULTS The 24-h average QTc in the hyperthyroid patients was significantly prolonged compared to controls (458 +/- 7 vs. 431 +/- 6 ms, P = 0.01) and it returned to normal after treatment of thyrotoxicosis (432 +/- 6 ms, P < 0.05 vs. time H, NS vs. controls). QTc positively correlated with FT3 (r = 0.63, P < 0.001) and with FT4 (r = 0.481, P < 0.02). Conversely, QTc did not correlate with plasma basal norepinephrine levels, nor with electrolytes. CONCLUSIONS Hyperthyroidism is associated with prolonged QTc that normalizes once the patient becomes euthyroid. The strong positive correlation between FT3 and QTc supports the hypothesis of an important role of thyroid hormone on modulation of QTc lengthening.
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Affiliation(s)
- R M Colzani
- Cardiovascular Neuroendocrine Unit, CNR Institute of Clinical Physiology, Via P. Savi, I-56126 Pisa, Italy
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Nattel S, Li D. Ionic remodeling in the heart: pathophysiological significance and new therapeutic opportunities for atrial fibrillation. Circ Res 2000; 87:440-7. [PMID: 10988234 DOI: 10.1161/01.res.87.6.440] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Heart disease has long been recognized to alter cardiac electrical function. Detailed studies of disease-induced remodeling of ionic transport processes that underlie ventricular electrophysiological alterations have been performed over the past 10 years, but our knowledge of atrial ionic remodeling is more limited and has emerged much more recently. The present review focuses on recent findings regarding ionic remodeling at the atrial level, particularly with respect to two conditions that promote atrial fibrillation (AF) in well-developed clinically relevant animal models: (1) sustained atrial tachycardia and (2) ventricular tachypacing-induced congestive heart failure. Complementary data from experimental models and from observations in atrial tissue samples from patients are examined critically and integrated. Consideration is also given to potential molecular mechanisms underlying remodeling, the relationship between atrial and ventricular ionic remodeling in response to similar stimuli, and the potential relevance of insights into ionic remodeling for understanding the pathophysiology of AF and developing improved therapeutic approaches.
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Affiliation(s)
- S Nattel
- Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Quebec, Canada.
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Singh BN, Doshi S. Maintaining sinus rhythm in atrial fibrillation by drug therapy: single agents or combinations? J Cardiovasc Pharmacol Ther 2000; 5:139-42. [PMID: 11150402 DOI: 10.1054/jcpt.2000.9072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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44
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Sun ZQ, Ojamaa K, Coetzee WA, Artman M, Klein I. Effects of thyroid hormone on action potential and repolarizing currents in rat ventricular myocytes. Am J Physiol Endocrinol Metab 2000; 278:E302-7. [PMID: 10662715 DOI: 10.1152/ajpendo.2000.278.2.e302] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Thyroid hormones play an important role in cardiac electrophysiology through both genomic and nongenomic mechanisms of action. The effects of triiodothyronine (T(3)) on the electrophysiological properties of ventricular myocytes isolated from euthyroid and hypothyroid rats were studied using whole cell patch clamp techniques. Hypothyroid ventricular myocytes showed significantly prolonged action potential duration (APD(90)) compared with euthyroid myocytes, APD(90) of 151 +/- 5 vs. 51 +/- 8 ms, respectively. Treatment of hypothyroid ventricular myocytes with T(3) (0.1 microM) for 5 min significantly shortened APD by 24% to 115 +/- 10 ms. T(3) similarly shortened APD in euthyroid ventricular myocytes, but only in the presence of 4-aminopyridine (4-AP), an inhibitor of the transient outward current (I(to)), which prolonged the APD by threefold. Transient outward current (I(to)) was not affected by the acute application of T(3) to either euthyroid or hypothyroid myocytes; however, I(to) density was significantly reduced in hypothyroid compared with euthyroid ventricular myocytes.
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Affiliation(s)
- Z Q Sun
- Pediatric Cardiology, New York University Medical Center, New York 10016, USA
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45
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Sun W, Sarma JS, Singh BN. Electrophysiological effects of dronedarone (SR33589), a noniodinated benzofuran derivative, in the rabbit heart : comparison with amiodarone. Circulation 1999; 100:2276-81. [PMID: 10578003 DOI: 10.1161/01.cir.100.22.2276] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND To overcome the side effects of amiodarone (AM), its noniodinated analogue, dronedarone (SR), was synthesized. In this study, its electrophysiological effects were compared with those of AM in rabbit hearts. METHODS AND RESULTS Five animal groups (n=7 each) for 3 weeks received daily oral treatment of 1 of these regimens: (1) control, vehicle only; (2) AM 50 mg/kg (AM50); (3) AM 100 mg/kg (AM100); (4) SR 50 mg/kg (SR50); and (5) SR 100 mg/kg (SR100). ECGs were recorded before drug and at 3 weeks of drug before euthanasia. Action potentials were recorded from isolated papillary muscle and sinoatrial node by microelectrode techniques. The short-term effects were studied in controls (n=5) at various concentrations of SR (0 to 10 micromol/L) in tissue bath. Action potential duration at 50% (APD(50)) and 90% (APD(90)) repolarization and upstroke dV/dt (V(max)) at various cycle lengths were compared by ANOVA with repeated measures. Compared with control, AM and SR increased RR, QT, and QTc intervals (P<0.0001 for all). Ventricular APD(50) and APD(90) were lengthened by 20% to 49% as a function of dose (P<0.005 to <0.0001) and cycle length (P<0.001). SR100 effects were greater than those of AM100 (P<0.002). V(max) was decreased by both AM100 (P<0.0001) and SR100 (P<0.01). Sinoatrial node automaticity was slowed in treated groups compared with that of the control group (P<0.0001 for all). CONCLUSIONS The electrophysiological effects of dronedarone are similar to those of AM but more potent, despite deletion of iodine from its molecular structure, a finding of importance for the development of future class III antiarrhythmic compounds.
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Affiliation(s)
- W Sun
- Cardiovascular Research Laboratory, Section of Cardiology, VA Medical Center of West Los Angeles and UCLA School of Medicine, Los Angeles, CA 90073, USA
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Shimoni Y. Hormonal control of cardiac ion channels and transporters. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1999; 72:67-108. [PMID: 10446502 DOI: 10.1016/s0079-6107(99)00005-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Y Shimoni
- Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Alta., Canada.
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47
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Shahrara S, Drvota V. Thyroid hormone alpha1 and beta1 receptor mRNA are downregulated by amiodarone in mouse myocardium. J Cardiovasc Pharmacol 1999; 34:261-7. [PMID: 10445678 DOI: 10.1097/00005344-199908000-00012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Amiodarone, a powerful antiarrhythmic drug, may exert its effect by antagonism of the thyroid hormone, probably at the receptor level. The aim of this study was to investigate whether amiodarone affects the levels of thyroid hormone receptor (TR) messenger RNA (mRNA) subtypes in mouse hearts. Mice were treated with 10, 25, and 50 mg/kg body weight (BW) amiodarone or vehicle (propyleneglycol) intraperitoneally, daily for 14 days. The heart rate dose-dependently decreased in the 25 mg/kg BW (p < 0.05) and 50 mg/kg BW (p < 0.005) amiodarone-treated mice compared with control. Serum T3 levels were significantly decreased by 25% (4.2 +/- 0.7 pM) in the 50 mg/kg BW amiodarone group in comparison to control (5.6 +/- 1.4 pM; p < 0.05). The serum T4 levels were 1.3 times higher in 50 mg/kg BW amiodarone-treated mice (13.2 +/-1.6 pM) compared with the control (10.3 +/- 1.3 pM; p < 0.005). Determination of TRalpha1, alpha2, beta1, and beta2 mRNA in the heart were performed by reverse transcriptase-polymerase chain reaction (RT-PCR)/enzyme-linked immunosorbent assay (ELISA). Both in treated and untreated mice, TRalpha2 mRNA had the highest density in mouse heart, whereas TRbeta2 mRNA had the lowest density. Amiodarone dose-dependently downregulated the levels of TRalpha1 and beta1 mRNA in comparison to the control. There were, however, no differences in the TRalpha2 and TRbeta2 mRNA levels in the mice heart treated with different doses of amiodarone in comparison with the control group. In conclusion, this study shows that amiodarone subtype selectively downregulates the TR mRNA levels in mouse myocardium in a dose-dependent manner. These results support a thyroid hormone-dependent action of amiodarone.
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Affiliation(s)
- S Shahrara
- Department of Cardiology, Karolinska Institute, Huddinge Hospital, Sweden
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Sorota S, Rybina I, Yamamoto A, Du XY. Isoprenaline can activate the acetylcholine-induced K+ current in canine atrial myocytes via Gs-derived betagamma subunits. J Physiol 1999; 514 ( Pt 2):413-23. [PMID: 9852323 PMCID: PMC2269084 DOI: 10.1111/j.1469-7793.1999.413ae.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
1. G protein betagamma subunits activate the acetylcholine-induced potassium current IK,ACh. There is no evidence of specificity at the level of the betagamma subunits. Therefore all G protein-coupled receptors in atrial myocytes should be able to activate IK,ACh. Paradoxically, it is often stated that isoprenaline does not activate IK,ACh. Rationales to explain this negative result include insufficient concentrations of Gs in the atrium or restricted access of Gs-derived betagamma subunits to the IK,ACh channel. We took advantage of a non-specific increase in Gs that results after infection with adenovirus. 2. Adenoviral infection unmasked a 1 microM isoprenaline-induced IK,ACh which was prevented by propranolol. Isoprenaline occasionally activated IK,ACh in uninfected and freshly dissociated atrial myocytes but the effect was larger and more consistent in infected myocytes. 3. Pertussis toxin pretreatment (100 ng ml-1 overnight) did not block the effect of isoprenaline. The effect of isoprenaline became persistent if cells were pretreated with cholera toxin (200 ng nl-1). 4. Signal transduction events distal to adenylyl cyclase were not involved in isoprenaline-induced IK,ACh. Forskolin (10 microM) did not activate IK,ACh. Inhibition of adenylyl cyclase with cytoplasmic application of 300 microM 2'-deoxyadenosine 3'-monophosphate did not prevent the activation of IK,ACh by isoprenaline. 5. Cytoplasmic application of a betagamma binding peptide derived from the C terminus of beta-adrenergic receptor kinase 1 (50 microM) prevented the effect of isoprenaline on IK,ACh. The peptide did not prevent the stimulation of the L-type calcium current by isoprenaline. 6. The results indicate that beta-adrenoceptors can activate IK,ACh in atrial myocytes through the release of betagamma subunits from Gs.
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Affiliation(s)
- S Sorota
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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49
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Affiliation(s)
- R P Choudhury
- Section on Clinical Pharmacology, Imperial College School of Medicine, Hammersmith Hospital, London
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50
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Venditti P, De Leo T, Di Meo S. Antioxidant-sensitive shortening of ventricular action potential in hyperthyroid rats is independent of lipid peroxidation. Mol Cell Endocrinol 1998; 142:15-23. [PMID: 9783898 DOI: 10.1016/s0303-7207(98)00123-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The effects of substances able to reduce peroxidative processes on thyroid hormone-induced electrophysiological changes in ventricular muscle fibres were examined. For this study, 60 day old euthyroid and hyperthyroid rats were used. One group of hyperthyroid rats was untreated and the others were treated with vitamin E, N-acetylcysteine, and cholesterol, respectively. Hyperthyroidism was elicited by 10 day treatment with daily i.p. injections of triiodothyronine (10 microg/100 g body weight). Vitamin E and N-acetylcysteine were administered for 10 days by daily i.m. injections (20 mg/100 g body weight) and daily i.p. injections (100 mg/100 g body weight), respectively. Cholesterol was administered by cholesterol-supplemented diet (4%) from day 30. Hyperthyroidism induced a decrease in the whole antioxidant capacity and an increase in both lipid peroxidation and susceptibility to oxidative stress. Vitamin E and N-acetylcysteine administration to hyperthyroid rats led to reduction in lipid peroxidation and susceptibility to oxidative stress and to increase in antioxidant level, while the diet addition of cholesterol decreased lipid peroxidation but did not modify the other parameters. The hyperthyroid state was also associated with a decrease in the duration of the ventricular action potential recorded in vitro. The vitamin E and N-acetylcysteine administration attenuated the thyroid hormone-induced changes in action potential duration, which was however, significantly different from that of the euthyroid rats. In contrast, cholesterol supplementation did not modify the electrical activity of hyperthyroid heart. These results demonstrate that the triiodothyronine effects on ventricular electrophysiological properties are mediated, at least in part, through a membrane modification involving a free radical mechanism. Moreover, they indicate that the antioxidant-sensitive shortening of action potential duration induced by thyroid hormone is likely independent of enhanced peroxidative processes in sarcolemmal membrane.
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Affiliation(s)
- P Venditti
- Dipartimento di Fisiologia Generale ed Ambientale di Napoli, Università Federico II di Napoli, Italy
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