Hyperthyroidism and cardiovascular complications: a narrative review on the basis of pathophysiology

Perioperative Care of a Child With Hyperthyroidism

In pediatric-aged patients, hyperthyroidism generally results from the autoimmune disorder, Graves' disease (GD). Excessive levels of thyroid hormones (triiodothyronine and thyroxine) result in irritability, emotional lability, nervousness, tremors, palpitations, tachycardia, and arrhythmias. The risk of morbidity and mortality is increased when surgical intervention is required in patients with hyperthyroidism due to the potential for the development of thyroid storm (TS). A 3-year, 1-month-old child with a past medical history of GD presented for total thyroidectomy when pharmacologic control with methimazole was not feasible due to intolerance following development of a serum sickness-like illness. Prior to surgery, his thyrotoxicosis symptoms worsened with fever, tachycardia, diaphoresis, and hypertension. He subsequently developed TS and was admitted to the pediatric intensive care unit where management included hydrocortisone, potassium iodide, and β-adrenergic blockade with esmolol and propranolol. Thyroid studies improved prior to surgery, and a total thyroidectomy was successfully completed. Corticosteroid therapy was slowly tapered as an outpatient, and he was discharged home on hospital day 9. Following discharge, his signs and symptoms of thyrotoxicosis resolved, and he was started on oral levothyroxine replacement therapy. The remainder of his postoperative and post-discharge course were unremarkable. Only two case reports of perioperative pediatric TS have been published in the past 20 years. Our case serves as an important reminder of the signs of TS in children and to outline the treatment options in a pediatric patient, especially in those unable to tolerate first-line pharmacologic therapies such as methimazole or propylthiouracil.

Comparison of Presentation Types and Clinical Findings of Rural and Urban Patients with Mastalgia: A Retrospective Analysis of 730 Patients from Turkey

BACKGROUND Breast pain, prevalent among women of reproductive age, varies during menstrual cycles and is influenced by sociodemographic and clinical factors. This study aimed to assess these demographic and clinical variables in women with breast pain, considering the spatial distinctions between urban and rural locations. MATERIAL AND METHODS This retrospective study included 730 women presenting with mastalgia between 2010 and 2023. The study evaluated patient demographics, pain characteristics (eg, breast pain duration, site, quadrant-based localization, and radiation of breast pain), radiologic findings, and the presence of comorbid medical conditions. RESULTS There were 498 patients in the urban group and 232 patients in the rural group. Among the radiologic findings, the rate of mastitis was higher in the rural group (P<0.05). Regarding the localization of breast pain within the quadrants, left breast upper-inner (LUI) quadrant pain was more common in the rural group (P=0.014). Regarding comorbid medical conditions, the prevalence of gastrointestinal system disease was higher in the rural group (P=0.009). Using logistic regression analysis, gastrointestinal disease was determined to be a significant independent risk factor for increased LUI quadrant pain in the rural group (odds ratio [OR]: 3.132, P=0.014), while pre-existing thyroid disease (OR: 2.482, P=0.004), hypertension (OR: 2.534, P=0.006), and radiologic evidence of ductal ectasia (OR: 2.878, P=0.03) were independent risk factors in the urban group. CONCLUSIONS Patient outcomes may be improved by a tailored, population-based approach to mastalgia patients in rural and urban locations focused on their radiologic findings and comorbid medical conditions.

Atrioventricular block in patients with hyperthyroidism: a narrative review

Atrioventricular block (AVB) is a rare cardiac manifestation of hyperthyroidism (HTH). The scientific literature contains multiple reports of AVB in patients with HTH, ranging from subclinical to overt HTH and even thyroid storm. However, much remains unknown about the true prevalence, clinical course, optimal management, and outcomes of AVB in patients with HTH. Such patients are possibly overtreated with pacemakers because of a lack of understanding that AVB might be secondary to the hyperthyroid state and thus reversible. This narrative review discusses the pathophysiology of AVB in patients with HTH in the context of the available evidence.

Cardiovascular sequelae of hyperthyroidism: A rare case report of thyrotoxic cardiomyopathy

INTRODUCTION

This case report highlights a distinctive presentation of cardiovascular sequelae arising from hyperthyroidism, shedding light on a rarely observed condition within the medical literature. The unique aspects of this case contribute valuable insights to our understanding of the intricate relationship between thyroid dysfunction and cardiac complications.

CLINICAL PRESENTATION

The patient exhibited a constellation of symptoms, including palpitations, weight loss, and anxiety, indicative of hyperthyroidism. Notably, a thorough clinical examination revealed critical cardiovascular findings, such as elevated heart rate, arrhythmias, and signs of heart failure, underscoring the significant cardiac implications associated with this disorder.

DIAGNOSIS AND INTERVENTIONS

Following a comprehensive diagnostic process, the patient was diagnosed with thyrotoxic cardiomyopathy, a rare manifestation of hyperthyroidism characterized by cardiac muscle dysfunction. Therapeutic interventions encompassed a multidisciplinary approach involving antithyroid medications, beta-blockers, and supportive heart failure management. The intricate connection between thyroid function and cardiac performance necessitated tailored treatment strategies.

OUTCOMES

A notable improvement in the patient's clinical status was observed throughout treatment. Reduction in heart rate, resolution of arrhythmias, and amelioration of heart failure symptoms collectively underscored the efficacy of the chosen interventions. This case report emphasizes the importance of prompt and accurate diagnosis and a comprehensive treatment regimen in achieving positive clinical outcomes in patients with thyrotoxic cardiomyopathy.

CONCLUSION

This case is a poignant reminder of the interplay between endocrine and cardiovascular systems. The unique presentation of thyrotoxic cardiomyopathy in the context of hyperthyroidism expands our knowledge of potential cardiovascular sequelae. Clinicians are urged to consider such intricate connections and remain vigilant for atypical cardiac manifestations in patients with thyroid dysfunction. Timely intervention and tailored management strategies are paramount in mitigating the impact of these rare yet clinically significant conditions.

Associations of serum keratin 1 with thyroid function and immunity in Graves' disease

BACKGROUND

Autoimmune thyroid disease (AITD) can cause enormous health burdens; however, trustworthy biomarkers in identifying the onset and progression of AITD are limited. In this study, we attempted to discover new potential serum biomarkers to discriminate AITD using mass spectrometry (MS).

METHODS

In the biomarker study cohort, 20 patients with Graves' disease (GD), 20 patients with Hashimoto's thyroiditis (HT), and 20 healthy controls were enrolled for a liquid chromatographic-tandem MS assessment. A novel biomarker, keratin 1 (KRT1), was selected for further evaluation in the validation cohort, including 125 patients with GD, 34 patients with HT, and 77 controls. Relationships of serum KRT1 with AITD-related immunomodulatory cytokines were also analyzed using enzyme-linked immunosorbent assays (ELISAs).

RESULTS

In the MS analysis, KRT1 was the single marker overexpressed in GD, while it was underexpressed in HT. In the ELISA analysis of the validation cohort, KRT1 was consistently upregulated in GD, while it was not downregulated in HT. There were significant associations of KRT1 levels with thyroid function in GD, AITD, and overall subjects. Additionally, a significant association of KRT1 levels with thyroid-stimulating hormone receptor antibody (TSHRAb) levels was observed. Moreover, there were significant associations of KRT1 with osteopontin (OPN) and B-cell activating factor (BAFF) levels in GD.

CONCLUSIONS

Serum KRT1 levels were upregulated in GD and were associated with thyroid function and TSHRAb levels. Moreover, KRT1 was correlated with the BAFF and OPN levels in GD patients. Further molecular-based research to elucidate the role of KRT1 in the pathogenesis of AITD is needed.

Mechanisms and Treatment Options for Hyperthyroid-Induced Osteoporosis: A Narrative Review

Normal thyroid hormone levels are crucial for the homeostasis of many metabolic cycles and processes throughout the human body. Thyroid dysfunction, such as thyrotoxicosis, can result from many different etiologies, including Graves' disease (GD), toxic multinodular goiter (MNG), and toxic adenoma. These hyperthyroid disease states can cause devastating complications and disease, including the disruption of the bone remodeling cycle and skeletal development, which can result in osteoporosis. Osteoporosis is characterized by a decrease in bone mineral density and a propensity for fragility fractures. In addition to patients with overt hyperthyroidism, studies have provided evidence of other high-risk patient demographics, such as individuals with subclinical hyperthyroidism and postmenopausal women, who may be at an increased risk for the development of secondary osteoporosis. The treatment of patients with hyperthyroid-induced osteoporosis often requires a multifaceted management plan that may be unique to each patient's situation. Antithyroid therapy is often the first step in treating this disease and may include thioamide medications. Radioactive iodine-131 therapy (RAI) and the surgical removal of the thyroid gland may also be reasonable approaches for restoring normal thyroid function. Following thyrotoxicosis mitigation, antiresorptive drugs such as bisphosphonates, calcitonin, and selective estrogen receptor modulators (SERMs) may be used to counteract decreased bone mineral density (BMD). Additionally, the implementation of vitamin D, calcium supplements, and weight-bearing exercise may also reduce bone loss. While the effects of thyroid stimulating hormone (TSH) and triiodothyronine (T3) on bone remodeling have been studied in the past, more research is needed to identify unknown mechanisms and develop future improved treatments for this condition.

When amiodarone-induced thyroiditis meets cardiomyopathy with excessive trabeculation: a case report

Introduction

Amiodarone is a potent antiarrhythmic medication used to treat life-threatening ventricular arrhythmias; however, its well-established adverse effect is a thyroid disorder. Amiodarone-induced thyroiditis (AIT), a clinical entity involving two types with different etiopathology and treatment approaches, may occur at the beginning or even several years after amiodarone treatment discontinuation. The toxicity profile of amiodarone becomes especially important in young patients with lifelong cardiac disorders, which are often refractory to other antiarrhythmic drugs. Herein, we report the first case of non-sustained ventricular tachycardia (NSVT), an unusual presentation of type II AIT, in a young male patient who was previously diagnosed with left ventricular cardiomyopathy with excessive trabeculation.

Case report

A 36-year-old male non-athlete presented with tiredness during regular follow-up. Continuous electrocardiographic monitoring (cECG) revealed NSVT, whereas echocardiography and cardiac magnetic resonance imaging detected discrete structural and functional changes that could not fully explain the observed cECG report. Conversely, an unmeasurably low thyrotropin level on admission and previous exposure to amiodarone pointed the diagnostic pathway in the direction of the thyroid gland. Elevated free thyroxine and undetectable autoantibody titers with unremarkable sonographic findings raised clinical suspicion of type II AIT. Scintigraphic imaging with 99mTc-2-methoxyisobutylisonitrile (sestamibi) revealed decreased thyroid uptake; hence, prednisone was introduced for treatment. Clear improvements in both biochemical and electrocardiographic parameters were observed after immunomodulatory treatment of type II AIT in this young patient with cardiomyopathy and excessive trabeculation.

Conclusion

Treatment of reversible causes of cardiac rhythm abnormalities such as type II AIT should be considered before choosing other treatment modalities, particularly in patients with structural cardiac disorders. The importance of a multidisciplinary approach in complex cases such as the one reported, thus, cannot be emphasized enough.

Resolution of Sinus Tachycardia Secondary to Hyperthyroidism With Ivabradine

Currently, ivabradine is not approved for the treatment of sinus tachycardia secondary to hyperthyroidism. We aimed to increase the recognition of ivabradine as an effective alternative to, or combination with, beta-blockers in controlling sinus tachycardia secondary to hyperthyroidism. Elevated thyroid hormone levels enhance cardiac performance through a positive chronotropic effect, resulting in an increased heart rate (HR), an effect brought on by increasing the I_f funny current at sinoatrial node (SAN). Ivabradine is a novel, dose-dependent selective inhibitor of I_f channels. By decreasing SAN pacemaker activity, ivabradine allows for selective reduction of HR with a resultant increase in ventricular filling time. This mechanism sets ivabradine apart from the typical rate-reducing medications, namely beta-blockers and calcium channel blockers, which simultaneously decrease HR and myocardial contractility. We describe a case of hyperthyroidism-induced sinus tachycardia, resistant to maximal doses of beta-blocker, which was successfully managed by ivabradine. After excluding other causes of tachycardia, such as anemia, hypovolemic states, structural heart disease, drug abuse, and infection, ivabradine was given off-label for symptomatic relief of hyperthyroidism-induced sinus tachycardia. Within 24 h, HR steadily decreased to the low 80s. Our patient had a unique presentation in which he presented with hyperthyroidism-induced sinus tachycardia with no relief after administration of maximal dose of beta-blocker. Ivabradine was then given, with resolution of sinus tachycardia within 24 h.

Safety and efficacy of prophylactic treatment for hyperthyroidism induced by iodinated contrast media in a high-risk population

Introduction

The use of iodinated contrast media (ICM) can lead to thyrotoxicosis, especially in patients with risk factors, such as Graves' disease, multinodular goiter, older age, and iodine deficiency. Although hyperthyroidism may have clinically relevant effects, whether high-risk patients should receive prophylactic treatment before they are administered ICM is still debated.

Aim of the study

We aimed to demonstrate the safety and efficacy of prophylactic treatment with sodium perchlorate and/or methimazole to prevent ICM-induced hyperthyroidism (ICMIH) in a population of high-risk cardiac patients. We ran a cost analysis to ascertain the most cost-effective prophylactic treatment protocol. We also aimed to identify possible risk factors for the onset of ICMIH.

Materials and methods

We performed a longitudinal retrospective study on 61 patients admitted to a tertiary-level cardiology unit for diagnostic and/or therapeutic ICM-procedures. We included patients with available records of thyroid function tests performed before and after ICM were administered, who were at high risk of developing ICMIH. Patients were given one of two different prophylactic treatments (methimazole alone or both methimazole and sodium perchlorate) or no prophylactic treatment. The difference between their thyroid function at the baseline and 11-30 days after the ICM-related procedure was considered the principal endpoint.

Results

Twenty-three (38%) of the 61 patients were given a prophylactic treatment. Thyroid function deteriorated after the administration of ICM in 9/61 patients (15%). These cases were associated with higher plasma creatinine levels at admission, higher baseline TSH levels, lower baseline FT4 levels, and no use of prophylactic treatment. The type of prophylaxis provided did not influence any onset of ICMIH. A cost-benefit analysis showed that prophylactic treatment with methimazole alone was less costly per person than the combination protocol. On multivariate analysis, only the use of a prophylactic treatment was independently associated with a reduction in the risk of ICMIH. Patients not given any prophylactic treatment had a nearly five-fold higher relative risk of developing ICMIH.

Conclusion

Prophylactic treatment can prevent the onset of ICMIH in high-risk populations administered ICM. Prophylaxis is safe and effective in this setting, especially in cardiopathic patients. Prophylaxis with methimazole alone seems to be the most cost-effective option.

Graves' Disease-Associated Dilated Cardiomyopathy Unmasked by Blunt Chest Trauma

Graves' disease can manifest with numerous cardiovascular complications, although very few cases result in cardiomyopathy. Our patient presented following a motor vehicle accident where she suffered blunt chest trauma. Her initial presentation was concerning for acute heart failure due to blunt cardiac injury, with diffuse pulmonary edema, hemodynamic instability, and an acutely reduced ejection fraction with global hypokinesis on transthoracic echocardiography. On further evaluation with thyroid function testing and autoimmune studies, she was found to have uncontrolled Graves' disease. She was subsequently started on methimazole for her Graves' cardiomyopathy. Following discharge, an outpatient cardiac MRI revealed no late gadolinium enhancement and complete recovery of her ejection fraction to normal values. This case serves to highlight the importance of a complete evaluation of cardiomyopathy and highlights an interesting case of a patient with blunt chest injury with a background of undetected Graves' cardiomyopathy.

A Role of Thyroid Hormones in Acute Myocardial Infarction: An Update

The acute coronary syndrome is one of the commonest life-threatening illnesses. It encompasses the clinical spectrum of acute myocardial ischemia and includes unstable angina and acute myocardial infarction both with and without ST segment elevation. The acute coronary syndrome can be attributed to a significant hemodynamic insult that leads to atherosclerosis of the epicardial coronary arteries. The main causative risk factors, such as obesity, smoking, and alcohol intake, increase the burden of acute coronary syndrome. Owing to an increase in the utilization of antioxidants, the antioxidant capacity decreases concerning the scavenging of lipid peroxides. Moreover, the thyroid hormones are important regulators of the expression of cardiac genes, and many of the cardiac manifestations of thyroid dysfunction are associated with alterations in triiodothyronine- mediated gene expression. Cardiovascular signs and symptoms of thyroid disease are among the most acute clinically relevant findings that occur in combination with both hypothyroidism and hyperthyroidism. By understanding the cellular mechanism of the action of thyroid hormones on the heart and cardiovascular system, it is possible to explain rhythm disturbances and alterations in cardiac output, blood pressure, cardiac contractility, and vascular resistance that result from thyroid dysfunction. Oxidative stress is thereby induced, together with a decrease in antioxidant capacity for overcoming oxidative stress, which leads to endothelial dysfunction, subsequent atherosclerosis, and, ultimately, acute myocardial infarction. The implications for the identification of the effects of thyroid disease on acute myocardial infarction include the observation that restoration of normal thyroid function repeatedly reverses abnormalities in cardiovascular hemodynamics.

A Cross-Sectional Study Examining the Parametric Thyroid Feedback Quantile Index and Its Relationship with Metabolic and Cardiovascular Diseases

Background: The usual inverse correlation between thyrotropin (TSH) and thyroid hormone disappears in syndromes of central resistance to thyroid hormone, where both are high. TSH and thyroid hormone are also simultaneously high when there is an elevation of the set point of the thyroid regulation axis. This can be estimated with indices, such as the Parametric Thyroid Feedback Quantile-based Index (PTFQI), which was designed for the general population. The PTFQI is positively associated with diabetes prevalence, but association with other pathologies has not been yet explored. The aim of this project was to explore the potential relationship of the PTFQI with metabolic and cardiovascular disease in a sample of ambulatory adult patients from Spain. Methods: A cross-sectional study was carried out among the patients who underwent thyroid hormones measurement (6434 measurements from September to November 2018 in a central laboratory in Spain). We retrospectively reviewed clinical records of a subgroup of adults aged >18 years with normal TSH and free thyroxine (fT4) belonging to groups that represent extreme PTFQI (n = 661). Individuals with known conditions interfering the thyroid axis were excluded (remaining n = 296). Logistic and linear regression models adjusted for age and sex were used to calculate odds ratio (OR) of diseases and differences of clinical parameters, and 95% confidence intervals [CI]. Results: Across levels with higher PTFQI, there was an increase in the prevalence of type 2 diabetes (High vs. Low PTFQI OR: 2.88 [CI: 1.14-7.86], p-Trend = 0.02), ischemic heart disease (16.4% vs. 0%, unadjusted Haldane-Anscombe corrected OR: 23.90 [CI: 1.36-21.48], adjusted p-Trend = 0.04), atrial fibrillation (OR: 8.13 [CI: 1.33-158.20], p-Trend = 0.05), and hypertension (OR: 3.19 [CI: 1.14-9.94], p-Trend = 0.05). While the prevalence of type 2 diabetes was similarly associated with TSH and fT4, ischemic heart disease, atrial fibrillation, and hypertension were more strongly associated with the differences in fT4 values. Conclusions: Type 2 diabetes, ischemic heart disease, atrial fibrillation, and hypertension may be associated with a higher central regulation set point for thyroid hormone. These findings should be confirmed in other populations.

Interplay between cardiovascular and thyroid dysfunctions: A review of clinical implications and management strategies

Cardiovascular diseases (CVD) and thyroid dysfunction are two of the most prevailing disorders in the world that are closely interlinked. Actions of thyroid hormones are mediated via thyroid receptors present in the myocardium and the vascular tissue. Primary mechanism that links thyroid dysfunction with CVD is the modification of cardiovascular risk factors (dyslipidemia, blood pressure, coagulation parameters, etc.) resulting in endothelial and left ventricular systolic and diastolic dysfunction.

Both overt and subclinical hyperthyroidism and hypothyroidism may cause adverse alterations in cardiac function. Hyperthyroidism gives rise to palpitation, atrial fibrillation, systolic hypertension, and heart failure, whereas hypothyroidism increases diastolic hypertension, pericardial effusion, and the risk of ischemic heart disease via altering lipid and coagulation parameters. Early recognition and treatment of thyroid dysfunction may prevent adverse cardiovascular events in patients with or without pre-existing CVD.

Certain cardiac conditions and medications can cause alterations in thyroid function that may predispose an individual to higher morbidity and mortality. In certain situations, thyroid dysfunction treatment may have cardiovascular benefits. This study deals with the interplay between cardiovascular and thyroid dysfunctions associated with clinical implications and management strategies.

Perioperative management of the thyrotoxic patients: A systematic review

Background

Thyrotoxicosis is a clinical syndrome produced by a multitude of disorders. Thyrotoxicosis is a serious medical condition that, if left untreated, can lead to a fatal illness. This review of recent evidences give additional input for perioperative management of thyrotoxic patients.

Methods

The literatures were found with Boolean operators in the form of thyrotoxicosis AND anesthesia, antithyroid medications AND perioperative optimization AND beta blockers OR calcium channel blockers in electronic data base sources such as the Cochrane library, PubMed, and Google scholar. This review was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement.

Conclusions

and recommendations: Before surgery and anesthesia, manifestation of thyrotoxicosis including palpitation, irritability etc should be ruled out.

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Thyrotoxicosis is a clinical syndrome produced by a multitude of disorders.

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Hyperthyroidism is a prevalent clinical condition that raises the risk of complications.

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Surgery and anesthesia should be postponed in elective thyrotoxicosis patients.

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Patients with thyrotoxicosis symptoms and elevated thyroid function tests should be optimized for 12–18 months.

Protective effects of Portulaca oleracea and vitamin E on cardiovascular parameters in rats with subclinical hyperthyroidism

INTRODUCTION

Subclinical hyperthyroidism (SHT) is an endocrine disorder that is associated with abnormalities in heart structure and function. Oxidative stress plays an important role in the pathophysiology of cardiac disorders caused by SHT. Portulaca oleracea (P. Oleracea) is a herbaceous plant with many pharmacologic effects including antioxidant, and anti-inflammatory properties. In the present study, the effects of Portulaca oleracea and vitamin E on the biochemical, hemodynamic, and functional parameters of the cardiac tissue was studied in rats with subclinical hyperthyroidism.

METHODS

Fifty-six male rats were divided into seven groups: 1-Control group: daily injection of saline, 2-SHT group: daily injection of levothyroxine sodium (LS) (20 µg/kg), 3- T4+Po groups were given LS and P. oleracea (100, 200, and 400 mg/kg in drinking water), 4- the T4+vit E groups received LS and a daily injection of vitamin E (100 and 200 mg/kg). Cardiac index, systolic blood pressure (SBP), also malondialdehyde and total thiol levels were measured in cardiac tissue.

RESULTS

SBP and maximum dP/dt were significantly increased and minimum dP/dt was significantly decreased in SHT group. In P. oleracea groups, maximum dP/dt were significantly reduced and minimum dP/dt was increased. Malondialdehyde levels and cardiac index in groups receiving vitamin E and P. oleracea were significantly decreased. Maximum dP/dt was decreased in the group receiving LS+vitamin E. Minimum dP/dt was significantly higher in group received LS+ vitamin E.

CONCLUSION

This study showed that Portulaca oleracea has a positive effect on cardiac dysfunction caused by subclinical hyperthyroidism.

The bidirectional relationship of thyroid disease and atrial fibrillation: Established knowledge and future considerations

Atrial fibrillation (AF) tends to occur frequently in patients with thyroid disease, primarily hyperthyroidism. In hyperthyroidism, increased levels of thyroid hormones, via intra- and extranuclear mechanisms, have profound effects on cardiac electrophysiology. Hypothyroidism carries a lower risk for AF and is mainly associated with the overtreatment of hypothyroid patients. New-onset AF is frequently the only manifestation of thyroid disease, which renders screening for thyroid dysfunction in that scenario clinically useful. Managing thyroid disease and comorbid AF is essential. This includes thyroid hormones control along with conventional AF therapy. However, there are several open issues with this comorbid duo. The optimal management of thyroid disease and its impact on AF burden remains obscure. There is scanty information on clear-cut benefits for therapy of subclinical thyroid disease and screening of asymptomatic patients. Furthermore, the immunogenetic overlap between the autoantibodies in Graves' disease and AF genesis may lead to novel therapeutic implications. The objective of this review is to summarize the up-to-date epidemiology, pathogenesis, pathophysiology and management of interacting thyroid disease and AF.

Pericardial Manifestations of Thyroid Diseases

PURPOSE OF REVIEW

Thyroid disorders, especially hypothyroidism, are known to be associated with pericardial diseases. The aim of this paper is to review the current knowledge of the pericardial manifestations of hypothyroidism and hyperthyroidism.

RECENT FINDINGS

Many reports have described associations between dysthyroidism, which encompasses hypothyroidism and hyperthyroidism, and several pericardial diseases, including acute pericarditis, constrictive pericarditis, pericardial effusion, and tamponade. The diagnosis of dysthyroidism-induced pericardial diseases consists of a combination of thyroid blood levels that fall outside of the normal range and the exclusion of other causes. Treatment of the thyroid disorder is key, along with treatment of the pericardial disease as recommended by the guidelines. Early recognition of the thyroid disorder is key in patients with pericardial diseases, since treating the underlying cause should assist resolution of the pericardial issues and ideally prevent recurrence and possible future complications of suboptimally treated pericarditis or pericardial effusions.

Supraventricular Tachycardia: An Atypical Presentation of Thyroid Storm

Thyroid storm (or thyrotoxic crisis) is commonly defined as a life-threatening condition caused by the exaggeration of the clinical manifestations of thyrotoxicosis. Supraventricular tachycardia (SVT) is an atypical precipitating symptom of thyrotoxicosis that clinicians should be aware of. An empirically derived scoring system known as the Burch-Wartofsky Point Scale (BWPS) has been used by clinicians since the early 1990s. The BWPS considers an array of precipitating factors and the severity of symptoms of multiple organ decompensation. In recent years, there has been an increasing correlation between SARS-CoV-2 and thyroid pathologies. We present a case of an unresponsive elderly male with a recent coronavirus disease 2019 (COVID-19) infection presenting with SVT and a BWPS score of 45, highly indicative of a thyroid storm.

Cardiovascular Manifestations in Hyperthyroidism: A Cross-Sectional Study in a Tertiary Care Hospital in South India

Background

The involvement of the heart in hyperthyroidism patients has a considerable prognostic value and causes significant morbidity and mortality. However, very little research, particularly among the Indian population, has addressed the most critical cardiovascular symptoms of hyperthyroidism, so this study aimed to assess the cardiovascular manifestations of hyperthyroidism.

Method

The current cross-sectional investigation involved 140 newly diagnosed and untreated confirmed cases of hyperthyroidism of any etiology for nine months. A structured data collection schedule was used to collect patient-specific and pertinent information during OPD hours or after admission. T4, T3, and TSH were measured in 10 mL of blood from each patient. The information was entered into a Microsoft Excel spreadsheet. All tests were carried out with a 5% level of significance.

Results

The mean age of study subjects was 43.2 years. Females made up 85.0% of the subjects in the current study, while males made up 15.0%. The etiology of hyperthyroidism was primarily due to Grave’s disease (59.3%). Heat intolerance (67.9%) was the most typical presenting symptom among the patients. The most common cardiac symptom was palpitation among 76.4% of subjects in the present study. Upon clinical examination, 80.7% of subjects had tachycardia. The ECG showed atrial fibrillation (AF) in 17.9% of subjects. The echocardiogram (ECHO) findings revealed systolic dysfunction in 17.8% of subjects.

Conclusion

Since cardiovascular manifestations are common in patients with thyroid disease and may be the only manifestation of thyroid disease, it is suggested that all patients with thyroid disorders be checked for cardiovascular manifestations. In addition, thyroid function tests should be performed in all patients with unexplained cardiovascular disease.

The effect of subclinical thyroid dysfunction on B- type natriuretic peptide level

Thyroid hormones (THs) have a significant effect on the cardiovascular system. THs increase myocardium stretch, leading to the release of B-type Natriuretic Peptide (BNP), which is considered a diagnostic biomarker of heart failure (HF). Thyroid dysfunctions (subclinical hypothyroidism; SCH and subclinical hyperthyroidism; SCHyper) stimulate several changes in the heart by causing either diastolic or systolic left ventricular dysfunctions leading to HF. This study aims to measure the changes of B- type NP levels in cases of subclinical hypo and hyperthyroidism. The present study aims to measure the changes in B-type Natriuretic Peptide (BNP) levels in subclinical hypo and hyperthyroidism (SCH and SCHyper). A theoretical study was also conducted using a docking program to find the effectiveness of some drugs in inhibiting or promoting B-type Natriuretic Peptide (BNP). A case study was conducted in a private clinic, Mosul- Iraq, from (April 1st – Sep 1) 2021, with 25 healthy participants with normal functioning thyroids as a control group (EU). A newly diagnosed 25 SCH and 17 SCHyper patients participated in this study, considering that none of them have thyroid dysfunctions taking medicine, hypertension, heart diseases, renal failure, and pregnant women. They all were checked for Thyroid Function Tests (TFTs), Free Triiodothyronine (FT3), Free Thyroxin (FT4) and Thyroid Stimulating Hormone (TSH). The plasma level of BNP was measured in all participants of the three groups. The results showed that the plasma level of BNP was higher in SCHyper patients (10.97 pg/ml) as compared to that of SCH patients (8.09 pg/ml) and EU subjects (8.27 pg/ml). Hereby, we could state that subclinical hyperthyroidism, SCHyper, triggers BNP release. Therefore, it should be kept in mind that any high BNP levels due to SCHyper should be considered a reliable diagnostic biomarker of heart failure (HF). Keywords. Thyroid hormone(TH), Subclinical hypothyroidism(SCH), Subclinical hyperthyroidism(SCHyper), Chronic heart disease(CHD), Heart failure(HF), B-type natriuretic peptide(BNP), Docking Study.

A Prolonged QTc Interval Leads to the Diagnosis of Hyperthyroidism in an Adolescent Boy

BACKGROUND

Syncope is a common cause of pediatric emergency department visits and carries a broad differential diagnosis, which includes a few rare but critical cardiac conditions.

CASE REPORT

We review the case of an adolescent boy who presented to the emergency department after a syncopal event. He was found to have a prolonged QTc interval on electrocardiogram (ECG), without personal or family history or known risk factors. He was screened for thyroid dysfunction on a second ED visit for presyncope and was subsequently diagnosed with hyperthyroidism. The patient was treated with methimazole for 2 weeks and a repeat ECG showed normalization of the QTc interval with a QTc reduction of more than 100 ms; routine thyroid studies showed correction of thyroid stimulating hormone and free thyroxine levels shortly thereafter. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case and review of the medical literature should raise awareness for the emergency physician to consider evaluation of thyroid function in pediatric patients with QT interval prolongation and vice versa, potentially averting dangerous dysrhythmias.

Endocrine system dysfunction and chronic heart failure: a clinical perspective

Chronic heart failure (CHF) leads to an excess of urgent ambulatory visits, recurrent hospital admissions, morbidity, and mortality regardless of medical and non-medical management of the disease. This excess of risk may be attributable, at least in part, to comorbid conditions influencing the development and progression of CHF. In this perspective, the authors examined and described the most common endocrine disorders observed in patients with CHF, particularly in individuals with reduced ejection fraction, aiming to qualify the risks, quantify the epidemiological burden and discuss about the potential role of endocrine treatment. Thyroid dysfunction is commonly observed in patients with CHF, and sometimes it could be the consequence of certain medications (e.g., amiodarone). Male and female hypogonadism may also coexist in this clinical context, contributing to deteriorating the prognosis of these patients. Furthermore, growth hormone deficiency may affect the development of adult myocardium and predispose to CHF. Limited recommendation suggests to screen endocrine disorders in CHF patients, but it could be interesting to evaluate possible endocrine dysfunction in this setting, especially when a high suspicion coexists. Data referring to long-term safety and effectiveness of endocrine treatments in patients with CHF are limited, and their impact on several "hard" endpoints (such as hospital admission, all-cause, and cardiovascular mortality) are still poorly understood.

Enlarged left atrium and decreased left atrial strain are associated with atrial fibrillation in patients with hyperthyroidism irrespective of conventional risk factors

The purpose of this study was to investigate factors associated with AF in patients with hyperthyroidism beyond heart failure (HF), coronary heart disease (CHD), or valvular diseases. A total of 136 patients (mean age, 52 ± 15 years; 86 [63%] female) who were diagnosed with hyperthyroidism for the first time were enrolled. Patients who had HF, CHD, or significant valvular diseases were excluded. Patients were classified into two groups according to the presence (group 1, n = 40) and absence of AF (group 2, n = 96). AF occurred in 40 (29%) patients and 23 (58%) of these patients showed paroxysmal AF. Among the symptoms of hyperthyroidism, the most common chief complaint was palpitation (30%). Advanced age, presence of prior cerebrovascular events, and presence of palpitations were associated with AF. Larger left atrial volume index (LAVI), increased left ventricular mass index, and decreased left ventricular ejection fraction (LVEF) and S' velocity were associated with AF. Among them, presence of palpitations and increased LAVI were independently associated with the occurrence of AF. In addition, strain analysis, decreased LA expansion index (EI), ejection fraction (EF), peak atrial longitudinal strain, contraction strain, and late diastolic strain rate (A sr) and systolic strain rate (S sr) were associated with the occurrence of AF and LAVI. Presence of palpitations and enlarged left atrium were associated with the occurrence of AF in patients with hyperthyroidism irrespective of conventional risk factors. Additional LA analysis revealed that decreased LA function was associated with AF and enlarged left atrium.

Acylated Ghrelin Attenuates l-Thyroxin-induced Cardiac Damage in Rats by Antioxidant and Anti-inflammatory Effects and Downregulating Components of the Cardiac Renin-angiotensin System

ABSTRACT

This study investigated the protective effect of acylated ghrelin (AG) against l-thyroxin (l-Thy)-induced cardiac damage in rats and examined possible mechanisms. Male rats were divided into five intervention groups of 12 rats/group: control, control + AG, l-Thy, l-Thy + AG, and l-Thy + AG + [D-Lys3]-GHRP-6 (AG antagonist). l-Thy significantly reduced the levels of AG and des-acyl ghrelin and the AG to des-acyl ghrelin ratio. Administration of AG to l-Thy-treated rats reduced cardiac weights and levels of reactive oxygen species and preserved the function and structure of the left ventricle. In addition, AG also reduced the protein levels of cleaved caspase-3 and cytochrome c and prevented mitochondrial permeability transition pore opening. In the left ventricle of both control + AG-treated and l-Thy + AG-treated rats, AG significantly increased left ventricular levels of manganese superoxide dismutase (SOD2), total glutathione (GSH), and Bcl2. It also reduced the levels of malondialdehyde, tumor necrosis factor-α (TNF-α), interleukin-6, and Bax and the nuclear activity of nuclear factor-kappa B. Concomitantly, in both treated groups, AG reduced the mRNA and protein levels of NADPH oxidase 1, angiotensin (Ang) II type 1 receptor, and Ang-converting enzyme 2. All the beneficial effects of AG in l-Thy-treated rats were prevented by the coadministration of [D-Lys3]-GHRP-6, a selective growth hormone secretagogue receptor subtype 1a antagonist. In conclusion, AG protects against hyperthyroidism-induced cardiac hypertrophy and damage, which is mainly due to its antioxidant and anti-inflammatory potentials and requires the activation of GHS-R1a.

Prediction of Genetic Factors of Hyperthyroidism Based on Gene Interaction Network

The number of hyperthyroidism patients is increasing these years. As a disease that can lead to cardiovascular disease, it brings great potential health risks to humans. Since hyperthyroidism can induce the occurrence of many diseases, studying its genetic factors will promote the early diagnosis and treatment of hyperthyroidism and its related diseases. Previous studies have used genome-wide association analysis (GWAS) to identify genes related to hyperthyroidism. However, these studies only identify significant sites related to the disease from a statistical point of view and ignore the complex regulation relationship between genes. In addition, mutation is not the only genetic factor of causing hyperthyroidism. Identifying hyperthyroidism-related genes from gene interactions would help researchers discover the disease mechanism. In this paper, we purposed a novel machine learning method for identifying hyperthyroidism-related genes based on gene interaction network. The method, which is called “RW-RVM,” is a combination of Random Walk (RW) and Relevance Vector Machines (RVM). RW was implemented to encode the gene interaction network. The features of genes were the regulation relationship between genes and non-coding RNAs. Finally, multiple RVMs were applied to identify hyperthyroidism-related genes. The result of 10-cross validation shows that the area under the receiver operating characteristic curve (AUC) of our method reached 0.9, and area under the precision-recall curve (AUPR) was 0.87. Seventy-eight novel genes were found to be related to hyperthyroidism. We investigated two genes of these novel genes with existing literature, which proved the accuracy of our result and method.

Pathophysiology of cardiogenic shock

PURPOSE OF REVIEW

We describe the pathophysiology of cardiogenic shock (CS), from the main pathways to the inflammatory mechanisms and the proteomic features.

RECENT FINDINGS

Although the classical pathophysiological pathways underlying CS, namely reduced organ perfusion due to inadequate cardiac output and peripheral vasoconstriction, have been well-established for a long time, the role of macro-and micro-hemodynamics in the magnitude of the disease and its prognosis has been investigated extensively only over the last few years. Moreover, to complete the complex picture of CS pathophysiology, the study of cytokine cascade, inflammation, and proteomic analysis has been addressed recently.

SUMMARY

Understanding the pathophysiology of CS is important to treat it optimally.

Chronic Alcohol Abuse-Induced Hypokalemia Might Lead to Delayed Diagnosis or Misdiagnosis of Thyrotoxic Periodic Paralysis

Thyrotoxic periodic paralysis is an uncommon and potentially life-threatening complication of thyrotoxicosis and hyperthyroidism characterized by acute and reversible episodes of muscle weakness and hypokalemia. Here is a 41-year-old Taiwanese male patient without any family history of hyperthyroidism presented to the emergency room of our institution with initial symptom of acute lower limb weakness. Laboratory analysis revealed uncommonly severe hypokalemia (<1.5 mEq/L). A thyroid function test revealed hyperthyroidism, and thyroid ultrasonography revealed findings compatible with Graves’ disease. However, symptoms such as nausea, vomiting, diarrhea, and heavy breathing were absent. He was administered with 15 mg of methimazole and 30 mg of propranolol per day for complications of hyperthyroidism. Then we exhaustively evaluated the patient’s history and lifestyle habits, and found that the patient had chronic alcohol abuse (an 1-L bottle 45%-48% liquor per week) for more than 10 years. In this case, chronic alcohol abuse may have increased the patient’s tolerance to the profound hypokalemia such that it did not immediately show critical symptoms. Therefore, according to this case report, we suggest that chronic alcohol consumption or abuse may lead patients, especially those with hyperthyroidism, to ignore or delay treatment. 

PERICARDIAL EFFUSION IN A PATIENT WITH HYPERTHYROIDISM: A CASE REPORT

Pericarditis and pericardial effusion are commonly associated with hypothyroidism. It is an uncommon association with hyperthyroidism. We present a case of pericarditis/pericardial effusion in a 28-year-old Nigerian lady with hyperthyroidism. There was resolution of the pericardial effusion with antithyroid medications and steroid therapy. We recommend a high index of suspicion of this association in patients with hyperthyroidism and/or Graves' disease.

Incident atrial fibrillation in patients with differentiated thyroid cancer: a meta-analysis

Differentiated thyroid cancer (DTC) represents the most common form of thyroid neoplasms and is becoming increasingly prevalent. Evidence suggests a possible relationship between DTC diagnosis and subsequent atrial fibrillation (AF). If confirmed, this may present an alarming health risk (AF) in an otherwise condition with a relatively good prognosis (DTC). The aim of this systematic review and meta-analysis is to provide for the first time a pooled estimate of AF incidence in DTC patients in comparison to healthy controls. A detailed search in electronic databases, clinical trial registries and grey literature was performed to identify studies reporting the incidence of AF in DTC patients. Newcastle-Ottawa quality assessment scale was used to assess study quality. We used a random effects (RE) generalized linear mixed model (GLMM) in pooling of individual studies and also calculated a prediction interval for the estimate of a new study. Six observational studies met the eligibility criteria, which included totally 187,754 patients with DTC and 199,770 healthy controls. The median follow-up period was 4.3 to 18.8 years; the incidence rate of AF was 4.86 (95% CI, 3.29 to 7.17, I2 = 96%) cases per 1000 person-years, while the incidence rate ratio was 1.54 (95% CI, 1.44 to 1.65, I2 = 0%, 95% PI, 1.33 to 1.78).This is the first meta-analysis to confirm that patients with DTC are at a high risk for developing AF, which may be attributed to a state of iatrogenic hyperthyroidism due to long-term thyrotropin suppression therapy.

Pediatric volvulus induced thyroid storm: A case report

Thyroid storm is an unusually rare but life-threatening pediatric occurrence, carrying significant mortality. Skewed towards the adolescent population, thyroid decompensation occurs due to inciting factors ranging from infection, trauma, surgery, burns, medications, direct thyroid trauma, and rarely volvulus. Emergent care focuses on both reversing the inciting event as well as quelling the metabolic hyperactivity associated with thyroid storm. In review of the available literature, this case is the first to date of thyroid storm secondary to malrotation with midgut volvulus in a previously euthyroid adolescent patient.

Thyroid Disease-Induced Hepatic Dysfunction: A Clinical Puzzle

The diagnostic evaluation of an individual with clinical and laboratory evidence of thyroid dysfunction in the setting of acute liver injury is crucial. There is a complex relationship between the thyroid and the liver, and so, it requires a careful elucidation of the inciting disease process before instituting a treatment plan. We discuss a patient who had presented with coagulopathy, encephalopathy, and laboratory evidence of acute liver injury, hence adjudged to have developed drug-induced acute liver failure and transferred for liver transplant evaluation. She was found to have liver dysfunction from uncontrolled thyroid disease, with immediate and rapid improvement after controlling severe hyperthyroidism.

M2 muscarinic autoantibodies and thyroid hormone promote susceptibility to atrial fibrillation and sinus tachycardia in an autoimmune rabbit model

NEW FINDINGS

What is the central question of this study? Do autoantibodies to the M2 muscarinic receptor (M2R-AAbs) have the potential to facilitate specific sustained tachyarrhythmias in the presence of thyroxine (T4 ) in rabbits? What is the main finding and its importance? The M2R-AAb and T4 jointly destabilized the electrophysiological properties, thus promoting the occurrence of atrial and sinus tachyarrhythmias in rabbits. These findings provide a practical basis for understanding the pathophysiological role of M2R-AAb alone and with T4 in arrhythmia induction and might provide an innovative option for treatment of Graves' disease with rhythm disturbance.

ABSTRACT

Activating autoantibodies toward the β1/2 -adrenergic receptors (β1/2AR-AAbs) and M2 muscarinic receptor (M2R-AAbs) are present in a high proportion of patients with Graves' disease. We previously demonstrated that β1/2AR-AAbs with or without the presence of M2R-AAbs in combination with excessive thyroxine (T4 ) increased the induction of sustained tachyarrhythmias in an autoimmune rabbit model. However, the separate role of M2R-AAbs and their interaction with T4 are not clear. The aim of this study was to investigate the impact of M2R-AAbs and T4 on the induction of cardiac arrhythmias in a similar rabbit model. Ten New Zealand White rabbits were randomly divided into two groups. In group A (n = 6), the rabbits were immunized with the second extracellular loop peptide of M2R and subjected to 2 weeks of T4 treatment. In group B (n = 4), the rabbits were treated only with T4 for 2 weeks. After induction of general anaesthesia, rabbits were subjected to an electrophysiological study at 0 (pre-immune), 6 (post-immune) and 8 weeks (post-immune+T4 treatment) in group A and at 0 (baseline) and 8 weeks (T4 treatment) in group B. Each rabbit served as its own control. In group A, high levels and activity of M2R-AAbs were detected in all immunized animals. Thyroxine in combination with immunization significantly increased induction of sustained sinus tachycardia and atrial fibrillation in comparison to the pre-immune state. In group B, T4 predominantly induced sustained sinus tachycardia. This study demonstrated that M2R-AAbs and T4 jointly increased the susceptibility to both sinus and atrial tachyarrhythmias. The data supported the pathophysiological role of M2R-AAbs in hyperthyroidism-associated supraventricular tachyarrhythmias.

Challenges in the Management of Thyrotoxicosis Associated with Atrial Fibrillation and Heart Failure: Two Case Reports

BACKGROUND

Thyrotoxicosis is a clinical syndrome with high amounts of free thyroid hormone levels causing elevated thyroid hormone function in body tissues. Prolonged effects of free thyroid hormones may lead to cardiac complications such as atrial fibrillation (AF) and heart failure (HF).

CASE 1

A 31-year-old female, was admitted due to difficulty in breathing, generalised body swelling and jaundice. She was dyspnoeic with an irregular heart rate, and presented with abnormal vitals, liver and thyroid function tests which were diagnostic for thyroid storm. She was managed over 32 days in-hospital stay with carbimazole, propranolol, hydrocortisone, digoxin and furosemide. Unfortunately, she was readmitted 6 months later with worsened HF symptoms and passed away.

CASE 2

A 57-year-old female, was admitted due to difficulty in breathing, bilateral lower limb swelling and jaundice. She was tachypnoeic with an irregular heart rate, and presented with abnormal liver enzymes and thyroid function tests which were diagnostic for thyrotoxicosis. She was managed with carbimazole, propranolol, digoxin and furosemide, and was discharged on the 6th hospital day.

CONCLUSION

Prolonged untreated thyrotoxicosis increases the risk of AF and HF. Early and monitored treatment and follow-up of hyperthyroidism is key to the management of AF and HF in achieving a better outcome.

The possible role of the seaweed Ulva fasciata on ameliorating hyperthyroidism-associated heart inflammations in a rat model

Cardiovascular diseases are key complications primarily associated with hyperthyroidism disorders. The present study sought to ameliorate hyperthyroidism-mediated cardiovascular inflammations and related oxidative stress paradigms in experimental rats using the broadly distributed green seaweed Ulva fasciata. Forty-eight adult male albino rats were recruited and randomly classified into six groups. Hyperthyroidism was stimulated using L-thyroxine sodium at a dose of 100 μg/kg i.p. for 3 weeks daily. Further, 200 mg/kg b.wt. concentration of the U. fasciata methanolic (U. fasciata-MeOH) extract was the recommended dose and administrated orally to the hyperthyroid rats. The standard commercial drug "propranolol hydrochloride" was also tested at a dose of 10 mg/kg i.p. to compare the findings obtained from the seaweed extract. A combined treatment with the U. fasciata-MeOH extract and propranolol hydrochloride was also assessed. Our results implied that the treatment of hyperthyroid rats with the U. fasciata-MeOH extract significantly reduced serum levels of the thyroid hormones T3 and T4, proinflammatory cytokines (TNF-α, MPO, and CRP), triglycerides and total cholesterol, as well as the cardiac biomarkers CK-MB, LDH, and troponin to thresholds close to those of the standard drug. In addition, levels of high-density lipoprotein cholesterol (HDL-C) and interleukin 10 (IL-10) were significantly upregulated. Hyperthyroid rats only treated with propranolol hydrochloride, or with a combination of the drug and the seaweed extract, conferred the same observations. Histopathological architecture boosted our interesting findings where the myocardium tissues in hyperthyroid rats, administrated the U. fasciata-MeOH extract or/and propranolol hydrochloride, exhibited more or less a normal structure as the control, reflecting the potential cardiovascular recovery exerted by this seaweed extract. In vitro DPPH, ABTS, and FRAP antioxidant assays of the U. fasciata-MeOH extract showed an outstanding ROS-scavenging potential. HPLC analysis of the U. fasciata-MeOH extract unraveled an inestimable valuable array of phenolics (mainly p-coumaric, gallic, ferulic, chlorogenic, and syringic acids) and flavonoids (hesperidin, kaempferol, catechin, quercetin, and rutin). Conclusively, the seaweed U. fasciata is a profitable source of antioxidant polyphenolics characterized by having a pharmaceutical potential against hyperthyroidism-linked cardiovascular inflammations and oxidative stress patterns due to their substantial free radical quenching properties, and also via regulating the signalling pathways of the proinflammatory, lipid profile, and cardiac biomarkers.

Frequency of Cardiovascular Manifestation in Patients With Hyperthyroidism

Introduction Cardiovascular manifestations are very common in hyperthyroidism. Various cardiovascular symptoms such as palpitations, exercise intolerance, dyspnea, angina, edema, and congestive heart failure are commonly reported in hyperthyroidism. In this study, we determine the frequency of cardiovascular signs, symptoms, and various conduction disorders associated with hyperthyroidism. Methodology This cross-sectional, observational study was conducted in the cardiology department of a tertiary care hospital in Pakistan in close association with the internal medicine department from August 2019 to December 2019. A total of 100 hyperthyroid patients confirmed based on thyroid stimulating hormone (TSH, also known as thyrotropin), free T₄ (FT₄; thyroxine), and free T₃ (FT₃; triiodothyronine) were enrolled in the study. Results The most common cardiovascular symptom in this study was palpitations identified in 72% of the participants, followed by breathlessness in 41% of the participants. The most common cardiovascular sign was a pulse rate of more than 100 beats per minute found in 72% of the participants. The most common abnormality in electrocardiogram (ECG) was sinus tachycardia in 39% of the participants, followed by atrial fibrillation in 22% of the participants. In echocardiography, 5% of the participants had systolic dysfunction. Conclusion In this study, cardiovascular signs, symptoms, ECG, and echo changes were very frequent in hyperthyroidism. Management of hyperthyroidism should include routine ECG and echo testing, and cardiologists should be involved in thorough cardiovascular examination.

A Blunted Sympathetic Function and an Enhanced Nitrergic Activity Contribute to Reduce Mesenteric Resistance in Hyperthyroidism

We aimed to determine whether an experimental model of hyperthyroidism could alter the function of sympathetic and nitrergic components of mesenteric innervation. For this purpose, male Wistar rats were divided into (1) control rats (CT) and (2) rats infused with L-Thyroxine (HT). Body weight gain and adipose tissue accumulation were lower in HT rats, while systolic blood pressure and citrate synthase activity in the soleus muscle were increased by HT. In segments from the superior mesenteric artery, the application of an electrical field stimulation (EFS) induced a vasoconstrictor response, which was lower in arteries from HT animals. The alpha-adrenoceptor antagonist phentolamine diminished EFS-induced vasoconstriction to a lower extent in HT arteries, while the purinergic receptor antagonist suramin reduced contractile response to EFS only in segments from CT. In line with this, noradrenaline release, tyrosine hydroxylase expression and activation and dopamine β hydroxylase expression were diminished in HT. The unspecific nitric oxide synthase (NOS) inhibitor L-NAME increased EFS-induced vasoconstriction more markedly in segments from HT rats. NO release was enhanced in HT, probably due to an enhancement in neuronal NOS activity, in which a hyperactivation of both PKC and PI3K-AKT signaling pathways might play a relevant role. In conclusion, perivascular mesenteric innervation might contribute to reduce the vascular resistance observed in hyperthyroidism.

Impaired Cardiovascular Function in Male Rats with Hypo- and Hyperthyroidism: Involvement of Imbalanced Nitric Oxide Synthase Levels

BACKGROUND AND OBJECTIVE

All three isoforms of nitric oxide (NO) synthase (NOS) are targets for thyroid hormones in the cardiovascular system. The aim of this study was to assess the effects of hypo- and hyperthyroidism on inducible (iNOS), endothelial (eNOS), and neural (nNOS) NOS levels in aorta and heart tissues of male rats.

METHODS

Rats were divided into control, hypothyroid, and hyperthyroid groups; hypo- and hyperthyroidism were induced by adding propylthiouracil (500 mg/L) and L-thyroxine (12 mg/L) to drinking water for a period of 21 days. On day 21, systolic blood pressure, heart rate, left ventricular developed pressure (LVDP), peak rate of positive and negative (±dp/dt) changes in left ventricular pressure as well as NO metabolites (NOx) and iNOS, eNOS, and nNOS protein levels in aorta and heart, were all measured.

RESULTS

Compared to controls, LVDP and ±dp/dt were lower in both hypo- and hyperthyroid rats. Compared to controls, heart rate and systolic blood pressure were lower in hypothyroid and higher in hyperthyroid rats. NOx levels in the heart of hypothyroid rats were lower (53%), whereas that in hyperthyroid rats were higher (56% and 40%) than controls. Compared to controls, hypothyroid rats had lower levels of eNOS, iNOS, and nNOS in the aorta (16%, 34%, and 15%, respectively) and lower iNOS and higher nNOS in heart tissue (27% and 46%). In hyperthyroid rats, eNOS levels were lower (54% and 30%) and iNOS were higher (63%, and 35%) in the aorta and heart while nNOS was lower in the aorta (18%).

CONCLUSION

Hypothyroidism increased while hyperthyroidism decreased the ratio of eNOS/iNOS in aorta and heart; these changes of NOS levels were associated with impaired cardiovascular function.

Cardiogenic Shock Induced by Anterior Pituitary Hypofunction and Thyrotoxicosis

Cardiogenic shock occurs when the heart is unable to pump enough blood for the needs of the body. Hypopituitarism is a condition in which the pituitary gland does not produce enough of one or more hormones, and it rarely occurs with thyrotoxicosis. We report a rare case of cardiogenic shock induced by anterior pituitary hypofunction and thyrotoxicosis. A 47-year-old woman was admitted twice to the hospital due to generalized worsening muscle pain for 13 days, and accompanied by a transient loss of consciousness. Cardiogenic shock developed during hospitalization, which improved with active resuscitative measures. Laboratory tests showed thyrotoxicosis. Pituitary magnetic resonance imaging (MRI) and relevant hormone tests confirmed anterior pituitary hypofunction. The patient was given hormone replacement therapy, which stabilized her condition. We believe cardiogenic shock may be a serious complication of hypopituitarism. We recommend establishing an expert system (ES) to facilitate the early diagnosis and treatment of cardiogenic shock, improve the professional skills of primary care physicians, and optimize treatment plans.

Apathetic Thyroid Storm with Cardiorespiratory Failure, Pulmonary Embolism, and Coagulopathy in a Young Male with Graves' Disease and Myopathy

A 38-year-old gentleman presented with thyroid storm with multiorgan involvement in the form of heart failure (thyrotoxic cardiomyopathy), respiratory failure (respiratory muscle fatigue), hepatic dysfunction, fast atrial fibrillation, pulmonary embolism, and disseminated intravascular coagulation (DIC). His Graves' disease (GD) remained undiagnosed for nearly 8 months because apart from weight loss, he has not had any other symptoms of thyrotoxicosis. The presentation of thyroid storm was atypical (apathetic thyroid storm) with features of depression and extreme lethargy without any fever, anxiety, agitation, or seizure. There were no identifiable triggers for the thyroid storm. Apart from mechanical ventilation and continuous veno-venous renal replacement therapy in the intensive care unit, he received propylthiouracil (PTU), esmolol, and corticosteroids, which were later switched to carbimazole and propranolol with steroids being tapered down. He was diagnosed with thyrotoxic myopathy which, like GD, remained undiagnosed for long (fatigability). A high index of suspicion and a multidisciplinary care are essential for good outcome in these patients.

Left Ventricular Diastolic and Systolic Functions in Patients with Hypothyroidism

Background and objectives: Long standing hypothyroidism may impair myocardial relaxation, but its effect on systolic myocardial function is still controversial. The aim of this study was to investigate left ventricular (LV) systolic and diastolic function in patients with hypothyroidism. Materials and Methods: This study included 81 (age 42 ± 13 years, 92% female) patients with hypothyroidism, and 22 age and gender matched controls. All subjects underwent a detailed clinical examination followed by a complete biochemical blood analysis including thyroid function assessment and anthropometric parameters measurements. LV function was assessed by 2-dimensional, M-mode and Tissue-Doppler Doppler echocardiographic examination performed in the same day. Results: Patients had lower waist/hip ratio (p< 0.001), higher urea level (p = 0.002), and lower white blood cells (p = 0.011), compared with controls. All other clinical, biochemical, and anthropometric data did not differ between the two groups. Patients had impaired LV diastolic function (lower E wave [p< 0.001], higher A wave [p = 0.028], lower E/A ratio [p< 0.001], longer E wave deceleration time [p = 0.01], and higher E/e' ratio [p< 0.001]), compared with controls. Although LV global systolic function did not differ between groups, LV longitudinal systolic function was compromised in patients (lateral mitral annular plane systolic excursion-MAPSE [p = 0.005], as were lateral and septal s' [p< 0.001 for both]). Conclusions: In patients with hypothyroidism, in addition to compromised LV diastolic function, LV longitudinal systolic function is also impaired compared to healthy subjects of the same age and gender. These findings suggest significant subendocardial function impairment, reflecting potentially micro-circulation disease that requires optimum management.

Relationship of thyroid dysfunction with cardiovascular diseases: updated review on heart failure progression

Heart disease remains the leading cause of death globally. Heart failure (HF) is a clinical syndrome that results from impairment of the ability of the ventricle to fill with or eject blood. Over the past two decades, accumulated evidence has revealed the contribution of thyroid hormones to cardiovascular (CV) events, exerting their action through genomic and non-genomic pathways within the cardiomyocytes. The pivotal role of thyroid hormones in maintaining cardiac homeostasis has been observed in previous investigations which suggest that the CV system is adversely impacted by fluctuations in thyroid hormone levels, such as those that occur in hypothyroidism, hyperthyroidism, and low triiodothyronine syndrome (LT₃S). Thyroid dysfunction has direct effects on myocardial contractility, systolic and diastolic blood pressure, heart mass, heart rate, ejection fraction, and heart output, which may ultimately lead to HF. Recent clinical data have shown that thyroid hormone replacement therapy for hypothyroid patients appears to provide the potential for reducing CV events. Therefore, this review aims to address the impact of thyroid hormone dysfunction on pathophysiological mechanisms contributing to the development and progression of HF.

Cardiovascular Outcomes of Thyroidectomy or Radioactive Iodine Ablation for Graves' Disease

BACKGROUND

Treatment options for Graves' disease (GD) include medical management with antithyroid medications, radioactive iodine (RAI) ablation, or total thyroidectomy (TT). Definitive treatment with RAI ablation may be associated with worse cardiovascular morbidity and mortality than TT. We sought to determine the rate of cardiovascular morbidity before and after definitive treatment for GD.

METHODS

This study is a retrospective single-institution study of sequential adult patients with GD from 2012 to 2018 treated with RAI ablation or TT. Patients with prior thyroid surgery or RAI ablation with subsequent thyroidectomy were excluded. Demographic and clinical variables were collected from diagnosis of GD to last follow-up. Data analysis was performed with descriptive statistics, univariate analysis with Fisher's exact test for categorical variables and the Mann-Whitney U test for continuous variables.

RESULTS

One-hundred and eighty-four patients underwent definitive treatment for GD during the study period, of which 164 met inclusion criteria. One hundred and ten patients (67%) in the study group had TT and 54 (33%) had RAI ablation with a mean dose of 18.4 mCi (standard deviation 6.1). There were no differences in clinical or demographic factors in patients undergoing RAI ablation versus TT for definitive treatment including age, sex, thyroid-stimulating hormone level, free thyroxine level, or thyroid-stimulating immunoglobulin level at time of diagnosis, nor was there any difference in pretreatment cardiovascular comorbidity. Patients with TT had higher rates of resolution of arrhythmia after treatment than those undergoing RAI ablation, P = 0.02. There were no differences in treatment-related complications between the groups.

CONCLUSIONS

For patients undergoing definitive treatment for GD, TT is associated with improved rate of resolution of cardiac arrhythmia compared with RAI ablation.

Supraventricular tachycardia in 23 cats; comparison with 21 cats with atrial fibrillation (2004-2014)

INTRODUCTION

Supraventricular tachycardia (SVT) has not been well described in cats. The aim of this study was to describe the signalment, clinical findings, and outcome for cats with SVT versus cats with atrial fibrillation (AF).

ANIMALS

Forty-four client owned cats are included in the study. 23 cats with SVT and 21 with AF.

METHODS

This is a retrospective study. Clinical characteristics were compared between groups using a two-sample t-test or Mann-Whitney U test. Kaplan-Meier survival curves were generated to assess for impact of rhythm diagnosis, presence of ventricular arrhythmia, left atrial diameter, heart rate and congestive heart failure (CHF) status on cardiac death. Differences in survival between groups were compared using Mantel-Cox logrank comparison of Kaplan-Meier survival curves.

RESULTS

Cats with supraventricular arrhythmias most commonly presented with respiratory distress (10 of 44 cats). Cats with AF had a slower median heart rate (220 [range: 180-260 beats per minute (bpm)] compared with cats with SVT (300 [range: 150-380] bpm, p < 0.001). All cats with AF had structural heart disease, whereas 4 cats with SVT had no structural abnormalities. Left atrial diameter was significantly larger in cats with AF (23.7 (16.2-40.1) mm compared with 19.1 (12.8-31.4) mm in SVT cats; p = 0.02). Median survival was 58 days (1-780) in cats with AF and 259 days (2-2295) in cats with SVT (p = 0.1). Cats with signs of CHF had a shorter survival time (p = 0.001).

CONCLUSIONS

Most cats with AF or SVT have advanced structural heart disease. Some cats with SVT had structurally normal hearts, suggesting that SVT in cats is not always a consequence of atrial enlargement.

Statin therapy in athletes and patients performing regular intense exercise - Position paper from the International Lipid Expert Panel (ILEP)

Acute and chronic physical exercises may enhance the development of statin-related myopathy. In this context, the recent (2019) guidelines of the European Society of Cardiology (ESC) and the European Atherosclerosis Society (EAS) for the management of dyslipidemias recommend that, although individuals with dyslipidemia should be advised to engage in regular moderate physical exercise (for at least 30 min daily), physicians should be alerted with regard to myopathy and creatine kinase (CK) elevation in statin-treated sport athletes. However it is worth emphasizing that abovementioned guidelines, previous and recent ESC/EAS consensus papers on adverse effects of statin therapy as well as other previous attempts on this issue, including the ones from the International Lipid Expert Panel (ILEP), give only general recommendations on how to manage patients requiring statin therapy on regular exercises. Therefore, these guidelines in the form of the Position Paper are the first such an attempt to summary existing, often scarce knowledge, and to present this important issue in the form of step-by-step practical recommendations. It is critically important as we might observe more and more individuals on regular exercises/athletes requiring statin therapy due to their cardiovascular risk.

Strangulation-Induced Thyrotoxicosis in a Patient with Undiagnosed Underlying Graves' Disease

Thyrotoxicosis is a constellation of symptoms including palpitations, tremors, agitation, and heat intolerance, caused by excess thyroid hormone. It can be life-threatening in its most serious form. We present a rare case of thyrotoxicosis provoked by mechanical trauma to the neck via strangulation in a young female with a history of self-resolving postpartum symptoms of hyperthyroidism one year prior, but no formal diagnosis of thyroid dysfunction. Although hyperthyroidism and posttraumatic stress have many similar features, thyroid storm is a life-threatening disorder that needs immediate intervention.

The role of fish oil in attenuating cardiac oxidative stress, inflammation and fibrosis in rat model of thyrotoxicosis

Hyperthyroidism is associated with cardiovascular complications. Fish oil reduces risk of cardiovascular diseases. This study aims to evaluate the impact of fish oil on myocardial oxidative stress, inflammation and fibrosis in rat model of thyrotoxicosis. Rats were randomized into four groups; control rats, fish oil treated rats (FO, 100mg omega-3/100g body weight/day), hyperthyroid rats (Hyper, i.p levothyroxine 3 mg/kg/day), and hyperthyroid rats treated with fish oil (Hyper + FO) for 8 weeks. Changes in oxidants/antioxidants, inflammatory and fibrotic markers were measured. Thyrotoxicosis increased serum endothelin-1, thiobarbituric acid reactive substances (TBARS) and reduced activities of cardiac catalase and super oxide dismutase (SOD). Cardiac fibrosis paralleled with a decrease of matrix metalloproteinase -2 (MMP2) levels were observed in Hyper group. Use of FO increased activities of SOD and catalase, increased TBARS levels, and attenuated cardiac fibrosis by normalizing MMP-2 levels. Use of FO may attenuate cardiac oxidative stress and fibrosis in hyperthyroid states.

THYROTOXICOSIS IN A PEDIATRIC PATIENT WITH SUPRAVENTRICULAR TACHYCARDIA AND BORDERLINE FEATURES OF THYROID STORM

OBJECTIVE

The objective of this report was to emphasize the early recognition of thyrotoxicosis in the assessment of a pediatric patient with tachycardia. We present here the case of a 17-year-old female who presented with supraventricular tachycardia and was found to be in a state of severe thyrotoxicosis with borderline features of a thyroid storm.

METHODS

A 17-year-old African American female presented to the hospital with complaints of nausea, vomiting, and diarrhea associated with palpitations for 1 week. Initial workup included electrocardiogram, total blood count, lipase, basic metabolic panel, and thyroid function tests.

RESULTS

Initial vital signs were significant for a temperature of 100.1°F, and tachycardia with a heart rate (HR) of 180 beats per minute (bpm). Initial telemetry was significant for supraventricular tachycardia with a HR of 180 bpm. Vagal maneuvers including carotid sinus massage were attempted first followed by 6 mg intravenous (IV) push and then 12 mg IV push of adenosine. However, the patient remained tachycardic with a HR in the 150s. Laboratory evaluation confirmed the presence of thyrotoxicosis with a thyroid-stimulating hormone of 0.17 μIU/mL (normal, 0.5 to 4.7 μIU/mL) with a free thyroxine of 4.90 ng/dL (normal, 0.8 to 2.0 ng/dL) and free triiodothyronine >20 pg/mL (normal, 1.95 to 5.85 pg/mL). She was subsequently treated with propranolol, methimazole, and hydrocortisone, which resolved her symptoms in a few hours.

CONCLUSION

Due to high mortality rates, severe thyrotoxicosis needs to be recognized and treated early. This case report highlights the importance of early recognition of thyrotoxicosis in the initial management of tachycardia in the pediatric population.