Thyrotoxic cardiac disease

Unusual Presentations of Thyrotoxic Tricuspid and Mitral Regurgitations in 62 Adults: A Systematic Review of Case Reports with In-depth Pathophysiological Review

Background

Thyrotoxicosis is related to cardiovascular mortality. This can be caused by several clinical manifestations involving the rare provocation of tricuspid regurgitation (TR) and mitral regurgitation (MR). However, there are still no clear data on thyrotoxic TR and/or MR. This study examines the progression of TR, MR, heart failure (HF) and pulmonary hypertension (PH) in response to the thyrotoxic heart manifestations, clinical characteristics and treatment approaches.

Methods

A PRISMA-based systematic search was conducted using PubMed and other databases up to 17 June 2023. The outcomes of this study were TR, MR, HF and PH with their progression on follow-up, clinical characteristics and treatment approaches.

Results

A total of 57 case reports involving 62 patients (45.77 ± 13.41 years) were included in this study. They were predominantly women (n=50; 80.65%) and diagnosed with Graves' disease (n=41; 75.81%). All patients were diagnosed with thyrotoxicosis, and this included 23 (37.10%) cases of thyroid storm. From echocardiographic studies, several patients improved clinically within the first 6 months of follow-up, including 20 TR patients (83.33%) in 6 months, nine MR patients (69.23%) in 3 months, eight HF patients (66.67%) in 2 months and 16 PH patients (76.19%) in 6 months.

Conclusion

Several mechanisms are involved in thyrotoxic TR and/or MR, including the direct thyroid hormone effect and the indirect effect of other hyperthyroidism-associated factors. Patients with thyrotoxic TR and/or MR, including those with HF and PH, can experience clinical and structural improvements following hyperthyroidism treatment in the first 6 months.

Reversible acute heart failure induced by thyrotoxic cardiomyopathy: A case report

RATIONALE

Thyrotoxic cardiomyopathy is a rare but severe complication of thyrotoxicosis, leading to episodes of acute heart failure. This case report highlights a rare presentation of thyrotoxic cardiomyopathy with low-output heart failure, emphasizing the importance of early diagnosis and comprehensive management. The report aims to increase awareness among clinicians about the potential reversibility of this condition and the effective strategies for managing such complex cases.

PATIENT CONCERNS

This patient presented with dyspnea and chest constriction, without any antecedent predisposing factors. Subsequently, the patient abruptly manifested symptoms indicative of acute heart failure during outpatient consultation. Electrocardiography revealed rapid atrial fibrillation with type A preexcitation syndrome, whereas cardiac ultrasonography demonstrated global cardiac enlargement with a diminished ejection fraction (EF).

DIAGNOSES

After a comprehensive evaluation, the patient was diagnosed with thyrotoxic cardiomyopathy, acute heart failure, and atrial fibrillation with preexcitation syndrome.

INTERVENTIONS

Immediate interventions comprised diuretic administration, oxygen therapy, and antiarrhythmic agents, addressing acute heart failure concomitant with preexcitation syndrome. Following a fortnight of comprehensive therapeutic measures, the patient was discharged with a prescription for oral medications, notably methimazole.

OUTCOMES

Following the intervention, the patient showed significant improvement with the resolution of heart failure symptoms and dyspnea, restoration of sinus rhythm, improved left ventricular ejection fraction (LVEF improved from 36% to 45%), and normalization of thyroid function. These outcomes underscore the efficacy of the intervention strategy and offer a hopeful prognosis for similar cases.

LESSONS

Thyrotoxicosis may cause cardiomyopathy in patients with heart failure that manifests as dilated cardiac chambers. Clinicians should carefully screen patients for this reversible condition. Diagnosis requires a comprehensive assessment of various tests, and the therapeutic goal is to restore normal thyroid function.

Thyrotoxic Cardiomyopathy: A Rare Case of Thyroid Storm Presenting as De Novo Heart Failure

Thyroid storm and heart failure represent formidable challenges in clinical practice. Their coexistence, however, poses an even greater threat to the patient's well-being. To facilitate early recognition and appropriate management, an understanding of the complex interplay between these two conditions is crucial. Through comprehensive assessment, vigilant monitoring, and prompt intervention, outcomes can be improved and the morbidity and mortality mitigated. We present a rare case of a 40-year-old male who presented with severe de novo heart failure and a concurrent thyroid storm. Despite an initial left ventricular systolic ejection fraction of 20% and evidence of global dilatation and hypokinesis on echocardiography, appropriate management resulted in improved clinical status and ultimately recovery of cardiac function.

Body Mass Index (BMI) Related Morbidity with Thyroid Surgery

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.

Data Analysis and Systematic Scoping Review on the Pathogenesis and Modalities of Treatment of Thyroid Storm Complicated with Myocardial Involvement and Shock

Thyroid storm (TS) is a rare and fatal endocrine emergency that occurs due to undiagnosed and inadequately treated hyperthyroidism after stressful conditions in patients with thyroid disorders. The objective of this systematic scoping review was to better understand the pathophysiology of TS and its complications, in terms of myocardial affection, tachyarrhythmia, and cardiogenic shock. In addition, we explored the pharmacological, mechanical, and surgical treatments for TS. We also evaluated the outcomes of TS according to sex and cardiac involvement. Additionally, analytical analysis was performed on the selected data. A literature review of peer-reviewed journals was carried out thoroughly using medical terms, MeSH on PubMed, Google Scholar, and combinations such as thyrotoxicosis-induced cardiomyopathy, thyroid storm, cardiogenic shock, myocardial infarction, endocrine emergency, Burch-Wartofsky score, extracorporeal circulatory support, and thyroidectomy. A total of 231 papers were eligible (2 retrospective studies, 5 case series, and 224 case reports) with a total of 256 TS patients with cardiac involvement between April 2003 and August 2023. All age groups, sexes, patients with TS-induced cardiomyopathy, non-atherosclerotic myocardial infarction, tachyarrhythmia, heart failure, shock, and different forms of treatment were discussed. Non-English language articles, cases without cardiac involvement, and cases in which treatment modalities were not specified were excluded. Female sex was predominant, with 154 female and 102 male patients. Approximately 82% of patients received beta-blockers (BBs), 16.3% were placed on extracorporeal membrane oxygenation (ECMO) support, 16.3% received therapeutic plasma exchange (TPE), and 13.8% underwent continuous renal replacement therapy (CRRT), continuous venovenous hemofiltration (CVVHD), or dialysis. Overall, 18 females and 16 males died. BB-induced circulatory collapse, acute renal failure, CRRT, and ventricular fibrillation were significantly associated with mortality. Awareness of TS and not only thyrotoxicosis is vital for timely and appropriate treatment. The early diagnosis and management of TS in cardiac settings, including pharmacological, mechanical, and surgical modalities, can save high-risk patients. Sex matters in the presentation, treatment, and mortality of this population. However, further large-scale, and well-designed studies are required.

Thyrotoxic Cardiomyopathy: State of the Art

Thyroid hormones, mainly triiodothyronine, have genomic and non-genomic effects on cardiomyocytes related to the contractile function of the heart. Thyrotoxicosis, which is the set of signs and symptoms derived from the excess of circulating thyroid hormones, leads to increased cardiac output and decreased systemic vascular resistance, increasing the volume of circulating blood and causing systolic hypertension. In addition, the shortening of the refractory period of cardiomyocytes produces sinus tachycardia and atrial fibrillation. This leads to heart failure. Approximately 1% of patients with thyrotoxicosis develop thyrotoxic cardiomyopathy, a rare but potentially fatal form of dilated cardiomyopathy. Thyrotoxic cardiomyopathy represents a diagnosis of exclusion, and prompt identification is crucial as it is a reversible cause of heart failure, and heart function can be recovered after achieving a euthyroid state using antithyroid drugs. Radioactive iodine therapy and surgery are not the best initial therapeutic approach. Moreover, it is important to manage cardiovascular symptoms, for which beta blockers are the first-line therapeutic option.

Cardio-Thyrotoxicosis Syndrome: A Review of Thyrotoxic Cardiovascular Disease

Thyrotoxicosis, an endocrine disorder characterized by elevated serum thyroid hormone levels of tri-iodothyronine (T3) and/or thyroxine (T4), can impact cardiovascular health in several ways. The cardiovascular system is often severely targeted by the thyrotoxic state, and the term "Cardio-thyrotoxic syndrome" has been proposed to encompass the various cardiovascular disease states resulting from thyrotoxicosis. In this review, we discuss various cardiovascular disorders resulting from the effects of thyrotoxicosis. It is important to keep a high index of suspicion for thyroid disorder in the setting of new atrial fibrillation, heart failure, and tachycardia-induced cardiomyopathy. Management of cardio-thyrotoxicosis involves control of heart rate and blood pressure and treatment of acute cardiovascular complications. Thyroid-specific therapy to achieve a euthyroid state will not only improve but even potentially reverse cardiovascular abnormalities.

Esmolol Is Not the Solution: Thyroid Storm With Atrial Fibrillation

Thyroid storm is a challenging medical emergency that requires urgent assessment and management in a timely manner. In this article, we report on a case of a 37-year-old female who presented to the emergency department with a thyroid storm complicated by atrial fibrillation (AF) with a rapid ventricular response with no clinical signs of heart failure. As part of her medical management to rate control her AF, she was started on an infusion of a short-acting beta blocker, esmolol, and shortly after, she developed cardiac arrest. This is the second case report published to highlight the significant response (cardiac arrest) of patients with thyroid storm complicated by AF to a low dose esmolol infusion as part of their medical management.

Thyrotoxicosis-Induced Cardiomyopathy With Systolic Dysfunction

Thyrotoxicosis-induced dilated cardiomyopathy is a rare but potentially life-threatening complication of thyrotoxicosis, with an incidence of <1%. This condition is characterized by a dilatation of the ventricular chamber and a decrease in cardiac contractility. Untreated, it can lead to irreversible changes in cardiac structure and function, including dilated ventricular chamber, a decrease in ejection fraction (EF), and an increased risk of atrial fibrillation. We present a case of a 39-year-old patient with a diagnosis of thyrotoxicosis-induced acute heart failure. A two-dimensional (2D) echocardiogram disclosed an ejection fraction of 36%, with diffuse mild dilation of the atria and ventricles with trace mitral and tricuspid regurgitation. The anti-thyroid-stimulating hormone (TSH) receptor was positive, and Grave's disease was diagnosed. The patient eventually returned to baseline functional status and could return to basic activities of daily living without limitations. The patient was encouraged to follow up with outpatient cardiology. Early diagnosis of cardiac involvement in patients with thyrotoxicosis is critical. Promptly delivered intensive treatment with the rapid achievement of euthyroid state can potentially reverse cardiac dysfunction and improve patient outcomes.

Mechanical circulatory support for thyrotoxicosis-induced cardiomyopathy

Thyroid storm is a life-threatening condition which, in rare cases, may lead to cardiogenic shock and dysrhythmias. Mechanical circulatory support with an Impella device or extracorporeal membrane oxygenation may be used as a bridge to recovery in these cases. This case involves a patient with thyrotoxicosis and reduced ejection fraction and hemodynamic instability requiring Impella device placement. After treatment with methimazole, Lugol's iodine, and hydrocortisone, he was weaned off mechanical circulatory support and made a full recovery. Mechanical circulatory support devices can be a useful bridging tool in reversible causes of cardiogenic shock, such as thyroid storm.

Mechanisms and Management of Thyroid Disease and Atrial Fibrillation: Impact of Atrial Electrical Remodeling and Cardiac Fibrosis

Atrial fibrillation (AF) is the most common cardiac arrhythmia associated with increased cardiovascular morbidity and mortality. The pathophysiology of AF is characterized by electrical and structural remodeling occurring in the atrial myocardium. As a source of production of various hormones such as angiotensin-2, calcitonin, and atrial natriuretic peptide, the atria are a target for endocrine regulation. Studies have shown that disorders associated with endocrine dysregulation are potential underlying causes of AF. The thyroid gland is an endocrine organ that secretes three hormones: triiodothyronine (T3), thyroxine (T4) and calcitonin. Thyroid dysregulation affects the cardiovascular system. Although there is a well-established relationship between thyroid disease (especially hyperthyroidism) and AF, the underlying biochemical mechanisms leading to atrial fibrosis and atrial arrhythmias are poorly understood in thyrotoxicosis. Various animal models and cellular studies demonstrated that thyroid hormones are involved in promoting AF substrate. This review explores the recent clinical and experimental evidence of the association between thyroid disease and AF. We highlight the current knowledge on the potential mechanisms underlying the pathophysiological impact of thyroid hormones T3 and T4 dysregulation, in the development of the atrial arrhythmogenic substrate. Finally, we review the available therapeutic strategies to treat AF in the context of thyroid disease.

No evidence of pulmonary hypertension revealed in an echographic evaluation of right-sided hemodynamics in hyperthyroid cats

OBJECTIVES

Hyperthyroidism is a common endocrinopathy affecting middle-aged to elderly cats, with multisystemic repercussions. Hyperthyroid humans show decreased lung compliance and increased cardiac output with subsequent left heart failure leading to pulmonary capillary congestion. Prognosis worsens with the development of increased pulmonary vascular pressures (ie, pulmonary hypertension [PH]) in hyperthyroid humans. The effect of excess thyroid hormone concentration on pulmonary arterial hemodynamics is unknown in cats. Assessing pulmonary vascular pressures in veterinary medicine relies heavily on echocardiographic measurements performed at the level of the heart and pulmonary trunk. This study investigated right-sided cardiac and pulmonary arterial hemodynamics in hyperthyroid cats using echocardiography.

METHODS

Echocardiographic examinations of hyperthyroid cats identified through a bi-institutional database search were reviewed for the determination of systolic pulmonary arterial pressure (PAP) and 20 other metrics. Values were compared with those of a healthy cat group using non-parametric statistical analyses.

RESULTS

Systolic PAP could not be determined in 23/26 hyperthyroid and 13/14 healthy cats owing to unmeasurable tricuspid regurgitation flow velocity. Hyperthyroid cats were roughly twice as old (P <0.001) and had 2-4-fold higher respiratory rates (P <0.001) than healthy cats. Hyperthyroid cats showed an increase in acceleration time-to-ejection time ratio of pulmonary flow (1.4-fold, P = 0.001), pulmonary artery velocity time integral (1.2-1.6-fold, P = 0.001), maximal pulmonary velocity (1.3-1.7-fold, P = 0.002), stroke volume (1.5-fold, P = 0.001) and cardiac output (1.6-fold, P <0.001) vs healthy cats. None of the other echocardiographic metrics reached statistical significance.

CONCLUSIONS AND RELEVANCE

Systolic PAP estimation proved unsuitable as a sole measurement for the assessment of PH in hyperthyroid cats owing to the frequent inability to interrogate tricuspid regurgitant flow velocity. Hyperthyroid cats have altered echocardiographic measures of pulmonary hemodynamics dissimilar to those reported in hyperthyroid humans. Differential effects of thyrotoxic cardiomyopathy on ventricular systolic function may underlie species differences.

Thyrotoxicosis in Africa: a systematic review and meta-analysis of the clinical presentation

Background

Thyrotoxicosis is a common endocrine disorder. The clinical presentation is variable, and it is often misdiagnosed or diagnosed late in Africa. This study was aimed at collating and analyzing the clinical characteristics of the disease across the continent so as to enhance correct and timely diagnosis.

Methods

The study is a systematic review with a meta-analysis. Studies, done in Africa, which documented the clinical features of thyrotoxicosis were selected. African Journal Online (AJOL), PubMed, SCOPUS and Google Scholar, Research Square, SciELO, and medRxiv were systematically searched using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The study quality was assessed using the Newcastle-Ottawa scale. Heterogeneity was determined using I2 statistic and Cochran’s Q test. LFK index and the symmetry of the Doi plot were used to assess publication bias.

Results

The eligible studies were 59 and the total sample size was 9592. The most common symptoms of thyrotoxicosis on the continent included palpitations (69%), weight loss (65%), heat intolerance (64%), tiredness (49%), increased appetite (49%), hyperhidrosis (48%), and insomnia (47%). The most common signs were thyromegaly (88%), tachycardia (67%), sweaty palms (54%), hand tremor (49%), and exophthalmos (49%). Atrial fibrillation, heart failure, and thyrotoxic heart disease were found in 9, 12, and 22% respectively. Other findings were hypertension (25%) and diabetes (9%).

Conclusion

Clinical presentation of thyrotoxicosis varies, and understanding these peculiarities would mitigate misdiagnosis and delayed diagnosis in Africa.

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.

Right heart failure in the setting of thyrotoxic valvulopathy: the pathophysiology of an often neglected diagnosis: a case report

Background

Hyperthyroidism has a significant, well-established impact on the cardiovascular system on both a molecular and circulatory level. The cardiac consequences of thyrotoxicosis are not uncommon, indicated by a 1.2% prevalence of this disorder in the United States. However, our case describes the less widely observed association between thyrotoxicosis and valvulopathy.

Case summary

A 69-year-old Hispanic male presented with a 3-week history of shortness of breath, intermittent chest pain, and lower extremity swelling. Transthoracic echocardiogram revealed a dilated left and right atrium with severe tricuspid regurgitation, moderate mitral regurgitation, malcoaptation of the tricuspid valve leaflets, and a myxomatous mitral valve. In addition, right ventricular systolic function was moderately reduced. A right and left heart catheterization was performed with findings of normal right heart pressures and normal coronary arteries, respectively. To further evaluate the aetiology of the patient’s heart failure, thyroid studies were sent, revealing a thyroid-stimulating hormone value of <0.010 uIU/mL and a free T4 of 1.96 ng/dL. A 4.9 cm lesion was seen on thyroid ultrasound. We concluded that the patient’s heart failure and notable valvular abnormalities were likely as a result of thyrotoxic heart disease. Furosemide and methimazole were initiated while inpatient, and the patient was discharged with close follow-up.

Discussion

We demonstrate a unique case of the possible hemodynamic and cellular effects of thyroid hormone on the development of primary and secondary valve dysfunction. This association is important for clinicians to be aware of, as treatment of its underlying aetiology can lead to improvement in a patient’s cardiac outcomes.

Tachycardia in hyperthyroidism: Not so common

Objective

The commonly held association of hyperthyroidism with sinus tachycardia and widened pulse pressure (PP) has not been reassessed in decades despite patients with hyperthyroidism in current practice not always present with these signs. The study objective was to assess prevalence and variability of sinus tachycardia and widened PP in present day among individuals with different degrees of hyperthyroidism.

Methods

Data was collected retrospectively from 248 adult patients in an outpatient setting with biochemical evidence of hyperthyroidism, recorded heart rate (HR) and blood pressure (BP) who were not treated with medications that can influence these parameters.

Results

Mean age was 42.0 ± 14.2 years with 66.9% being female. Median free thyroxine (fT4) level was 3.49 (IQR 2.42–4.58) ng/dL and thyroid stimulating hormone (TSH) 0.02 (IQR 0.01–0.03) mIU/L. Tachycardia, defined as HR >100 bpm, was present in 28.2%. In the lowest and highest fT4 quartiles, tachycardia was present in 16.4% and 38.7% respectively. Using logistic regression, tachycardia was associated with higher fT4 and diastolic BP. More lenient outcome of tachycardia with HR >90 bpm was seen in 47.2%. Widened PP, defined as >50 mmHg, was observed in 64.1% of patients and correlated with higher fT4 and BP.

Conclusions

Tachycardia is not a common feature of hyperthyroidism today. The relatively infrequent finding of tachycardia in this study compared to older studies may reflect differences in the way medicine is practiced today. The increased ordering of thyroid function tests most likely unmasked cases of mild or asymptomatic thyrotoxicosis. A widened PP was a more prevalent clinical finding in this study.

Minor perturbations of thyroid homeostasis and major cardiovascular endpoints—Physiological mechanisms and clinical evidence

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.

Hemodynamic variation is a dominant contributing factor of Graves' hyperthyroidism complication: Heart failure and fatal liver dysfunction, a case report and analysis

Tachycardia and atrial fibrillation, early symptoms of hyperthyroidism indicate significant hemodynamic variation in cardiovascular system, if left untreated and further deterioration in hemodynamics can result in chronic heart failure and liver dysfunction even a fatal event. We describe a female patient of Graves' hyperthyroidism to present the continuum of the pathophysiology development of the disease, to highlight the hemodynamic variation is a dominant contributing factor of Graves' hyperthyroidism complication, we wish to emphasize cardiac manifestations in the setting of thyrotoxicosis should be treated promptly and aggressively.

Thyrotoxicosis-Induced Cardiomyopathy Complicated by Refractory Cardiogenic Shock Rescued by Extracorporeal Membrane Oxygenation

Patient: Male 53-year-old

Final Diagnosis: Thyrotoxicosis-induced cardiomyopathy

Symptoms: Dyspnea

Medication:—

Clinical Procedure: —

Specialty: Cardiology • Critical Care Medicine

Diltiazem-Induced Reversible Cardiogenic Shock in Thyroid Storm

Early recognition of underlying thyroid disease in patients presenting with new-onset tachyarrhythmia is central to management, as usual rate-control strategies can result in significant mortality and morbidity. Hyperthyroidism-induced cardiomyopathy complicated by cardiogenic shock is a life-threatening condition. Thyroid storm can lead to irreversible cardiovascular collapse and death if proper treatment is not initiated as soon as possible. In this case, we report a 44-year-old female who presented to the emergency department (ED) with the chief complaints of anxiety and palpitations. Her past medical history was significant for anxiety, but she was otherwise healthy. An electrocardiogram (ECG) in the ED demonstrated atrial fibrillation (A. fib) with rapid ventricular response (RVR) felt to be secondary to thyroid storm based on the Burch-Wartofsky point scale (BWPS), which is a quantitative diagnostic tool that uses clinical manifestation in diagnosing thyroid storm. The patient was initially managed with a continuous infusion of diltiazem to achieve rate control with a goal heart rate <115 beats per minute (bpm). Shortly after initiating the infusion, the patient developed signs and symptoms consistent with cardiogenic shock. Bedside echocardiogram revealed an estimated ejection fraction (EF) <10% with concomitant pulmonary edema. Repeat echocardiogram within 72 hours after stopping diltiazem and starting appropriate treatment for thyroid storm showed improvement of EF to 35%. 

Thyroid Hormone Plays an Important Role in Cardiac Function: From Bench to Bedside

Thyroid hormones (THs) are synthesized in the thyroid gland, and they circulate in the blood to regulate cells, tissues, and organs in the body. In particular, they exert several effects on the cardiovascular system. It is well known that THs raise the heart rate and cardiac contractility, improve the systolic and diastolic function of the heart, and decrease systemic vascular resistance. In the past 30 years, some researchers have studied the molecular pathways that mediate the role of TH in the cardiovascular system, to better understand its mechanisms of action. Two types of mechanisms, which are genomic and non-genomic pathways, underlie the effects of THs on cardiomyocytes. In this review, we summarize the current knowledge of the action of THs in the cardiac function, the clinical manifestation and parameters of their hemodynamics, and treatment principles for patients with hyperthyroid- or hypothyroid-associated heart disease. We also describe the cardiovascular drugs that induce thyroid dysfunction and explain the mechanism underlying the thyroid toxicity of amiodarone, which is considered the most effective antiarrhythmic agent. Finally, we discuss the recent reports on the involvement of thyroid hormones in the regulation of myocardial regeneration and metabolism in the adult heart.

Cardiovascular Events in Patients with Thyroid Storm

CONTEXT

Thyroid storm can present as a multitude of symptoms, the most significant being cardiovascular (CV). It is associated with various manifestations such as cardiac arrhythmia, heart failure, and ischemia. However, the frequencies of events and characteristics associated with patients that experience these events are not known.

METHODS

Study cohort was derived from the National Inpatient Sample database from January 2012 to September 2015. Total hospitalizations of thyroid storm were identified using appropriate ICD-9 diagnostic codes. The analysis was performed using SAS.

OBJECTIVE

To better understand the frequency and characteristics CV occurrences associated with thyroid storm, through a retrospective analysis of thyroid storm hospital admissions.

DESIGN

The study cohort was derived from the National Inpatient Sample database from January 2012 to September 2015.

SETTING

Total hospitalizations of thyroid storm were identified using International Classification of Diseases (ICD)-9 diagnostic codes. The analysis was performed using Statistical Analysis System (SAS).

RESULTS

A total of 6380 adult hospitalizations were included in the final analysis, which includes 3895 hospitalizations with CV events (CEs). Most frequently associated CEs were arrhythmia (N = 3770) followed by acute heart failure (N = 555) and ischemic events (N = 150). Inpatient mortality was significantly higher in patients with CEs compared with those without CEs (3.5% vs 0.2%, P < 0.005). The median length of stay was also higher in patients with CEs compared with those without CEs (4 days vs 3 days, P < 0.0005). Atrial fibrillation was the most common arrhythmia type, followed by nonspecified tachycardia.

CONCLUSIONS

In patients who were hospitalized due to thyroid storm and associated CEs significantly increased in-hospital mortality, length of stay, and cost. Patients with obesity, alcohol abuse, chronic liver disease, and COPD were more likely to have CEs. Patients with CV complications were at higher risk for mortality. In-hospital mortality increased with ischemic events and acute heart failure. Further evaluation is needed to further classify the type of arrhythmias and associated mortality.

Clinical phenotypes and prognosis of thyrotoxic heart failure and cardiomyopathy in patients hospitalized for acute heart failure

Background

We sought to examine clinical characteristics and outcomes in patients hospitalized for acute heart failure (HF) and thyrotoxicosis.

Methods

Patients with thyrotoxic HF were compared with age and gender‐matched patients hospitalized for acute HF (controls). Thyr‐HF was defined by the Framingham criteria for HF and clinical hyperthyroidism. Thyrotoxic cardiomyopathy was defined as left ventricular ejection fraction (LVEF) < 55%.

Results

Of 11 109 consecutive patients hospitalized for acute HF between 1 January 2002 and 1 January 2017, 92 patients (0.8%) had thyrotoxic HF. Clinical and echocardiographic data were available in 87 patients (age 51 ± 16 years; 74% female), representing the study population. Compared with controls, patients with Thyr‐HF had a smaller body surface area (BSA), a higher LVEF, a lower LV end‐diastolic diameter, a higher tricuspid annular plane systolic excursion (TAPSE), higher blood pressure, higher heart rate, and were more likely to have right‐sided HF at presentation (P < 0.01 for all). The survival rate among patients with thyrotoxic HF was higher than the control group (HR: 4.3; 95% CI: 2.1–9.5). Fifty‐eight percent of patients with thyrotoxic HF had thyrotoxic cardiomyopathy. In multivariate analysis, TAPSE (OR = 46; 95% CI: 1.04–2008.20; P = 0.047) and leukocytosis (OR = 16; 95% CI 1.01–259.39; P = 0.049) correlated with thyrotoxic cardiomyopathy. LV recovery was observed in 69% of these patients.

Conclusions

Thyrotoxic HF was uncommon among patients hospitalized for acute HF. However, after definitive therapy, these patients had a more favourable prognosis than those hospitalized for acute HF without thyrotoxic HF. Clinical phenotypes of thyrotoxic HF include small BSA, middle‐aged female, HF‐pEF, and right‐sided HF. Thyrotoxic cardiomyopathy affected over half of the patients with thyrotoxic HF with a two‐third recovery rate.

Delayed diagnosis of dilated thyrotoxic cardiomyopathy with coexistent multifocal atrial tachycardia: a case report

Background

Thyroid storm (TS) is a rare but potentially life-threatening sequelae of untreated or undertreated hyperthyroidism. While TS frequently causes high-output heart failure, low-output heart failure related to dilated cardiomyopathy (DCM) is extremely rare. Tachycardia is a common clinical presentation of TS, and β1-selective blockers are the first-line agents for treating TS-associated tachycardia. However, given that β-blockers have negative chronotropic and negative inotropic effects, amiodarone may be safe and effective for the treatment of TS-induced tachyarrhythmia in patients with moderate to severe heart failure. While long-term amiodarone administration causes hypothyroidism, or less frequently, hyperthyroidism, little is known about the effects of short-term amiodarone administration on thyroid function.

Case presentation

A 31-year-old healthy woman presented with worsening dyspnoea. She was tachycardic with multifocal atrial tachycardia (MAT) of 184 beats/min, confirmed by electrocardiogram. Echocardiographic findings were consistent with DCM, with an ejection fraction of 20%. Thus, she was initially diagnosed with acute heart failure due to DCM with coexistent MAT. Tachycardia persisted despite cardioversion attempts and treatment with multiple anti-arrhythmic drugs. Consequently, she rapidly progressed to cardiogenic shock and respiratory decompensation, which required intubation and an intra-aortic balloon pump support. Moreover, the undiagnosed Graves' disease, lack of suspicion, and postponed analysis of thyroid function tests led to a delayed diagnosis of TS. Amiodarone, which was initiated for MAT, unexpectedly ameliorated thyrotoxicosis, resulting in a euthyroid state and the patient’s significantly improved condition and cardiac function. She was discharged on day 40. Finally, she underwent total thyroidectomy; thyroid pathology was consisting with Graves' disease. Her postoperative course was uneventful.

Conclusions

Herein, we describe a case of delayed diagnosis of dilated thyrotoxic cardiomyopathy with coexistent MAT. The patient required intensive care due to the catastrophic sequelae and was successfully treated with amiodarone. This is the first case report of TS-associated MAT and highlights the clinical importance of high suspicion of TS in de novo heart failure with any tachyarrhythmia or DCM of unknown etiology and the potential effects of short-term amiodarone administration in the treatment of TS.

Cardiogenic shock in thyroid storm: A biventricular impella (Bi-Pella) approach

The use of biventricular impella support in patients with acute, reversible causes of biventricular cardiogenic shock may play a role in shortening the time to recovery and preventing significant negative outcomes such as renal or hepatic failure.

Crash Landing of Thyroid Storm: A Case Report and Review of the Role of Extra-Corporeal Systems

Thyroid storm is a rare but life-threatening endocrinological emergency with significant mortality ranging from 10-30% with multi-organ involvement and failure. In view of the rarity of this condition and efficacy of established first line medical treatment, use of extra-corporeal treatments are uncommon, not well-studied, and its available evidence exists only from case reports and case series. We describe a 28-year-old man who presented with an out-of-hospital cardiac arrest secondary to thyroid storm. Despite conventional first-line pharmacotherapy, he developed cardiogenic shock and circulatory collapse with intravenous esmolol infusion, as well as multi-organ failure. He required therapeutic plasma exchange, concurrent renal replacement therapy, and veno-arterial extra-corporeal membrane oxygenation, one of the few reported cases in the literature. While there was clinical stabilization and improvement in tri-iodothyronine levels on three extra-corporeal systems, he suffered irreversible hypoxic-ischemic brain injury. We reviewed the use of early therapeutic plasma exchange and extra-corporeal membrane oxygenation, as well as the development of other novel extra-corporeal modalities when conventional pharmacotherapy is unsuccessful or contraindicated. This case also highlights the complexities in the management of thyroid storm, calling for caution with beta-blockade use in thyrocardiac disease, with close monitoring and prompt organ support.

Endocrine causes of heart failure: A clinical primer for cardiologists

Heart failure (HF) may be a presenting manifestation of a few endocrine disorders and should be considered in evaluation of heart failure causes. This clinically oriented review is an attempt to highlight the protean manifestations of heart failure in endocrine diseases which could present either as acute or chronic heart failure. Acute heart failure manifests as hypertensive crisis, Takotsubo syndrome, or as tachy/brady cardiomyopathies. Chronic heart failure could masquerade with features of hyperdynamic heart failure, or hypertrophic, restrictive or dilated cardiomyopathy. Rarely constrictive features or resistant heart failure could be the presenting feature. Isolated presentation as pulmonary hypertension and right heart failure are also documented. Good history-taking and physical examination with targeted investigations will help in the timely management for reversing the pathophysiology to a significant extent by appropriated management.

New-onset arrhythmia associated with patients hospitalized for thyroid dysfunction

BACKGROUND

Thyroid dysfunction has been associated with cardiovascular dysfunction in the literature. However, the frequency of new-onset arrhythmias associated with thyroid disease hospitalization is unknown. Hence, we analyzed frequency, in-hospital outcomes, and resource utilization of new-onset arrhythmias associated with thyroid dysfunction hospitalizations.

METHODS

The patients who were admitted with the primary reason of thyroid dysfunction were included using appropriate international classification of disease, ninth revision, clinical modification (ICD-9-CM) codes. We then identified new-onset arrhythmias using appropriate ICD-9-CM codes. We utilized the "present on admission" variable to exclude arrhythmias that were present on admission.

RESULTS

Among the eligible patients with thyroid dysfunction, only 3% (n=12,111) developed a new-onset arrhythmia. Atrioventricular block (1.49%) is the most frequent followed by atrial fibrillation (0.92%), ventricular tachycardia (0.47%), atrial flutter (0.23%), supraventricular tachycardia (0.1%) and ventricular fibrillation (0.07%). Patients with new-onset arrhythmias were older (mean age 76.7±12.5 years), more predominantly white (n=9008, 74.4%), higher females (n= 7632, 63%), and had a higher frequency of comorbidities. In-hospital mortality occurred in 827 (6.8%) patients with new-onset arrhythmias and 8632 (2.2%) patients without new-onset arrhythmias (P-value <0.001). The medical length of stay and cost of hospitalization was also higher in these patients.

CONCLUSION

Thyroid dysfunction is not associated with significantly higher rates of new-onset arrhythmias while inpatient. However, when developed, these arrhythmias are associated with higher mortality and resource utilization. The patients admitted to the hospital should have thyroid function checked when found to have an arrhythmia.

Comparison of 24-Hour Electrocardiogram Parameters in Patients with Graves' Disease Before and After Anti-Thyroid Therapy

BACKGROUND

We aimed prospectively to investigate the laboratory and electrocardiographic parameters (heart rate, QRS, QT, QTc, Tpe, Tpe/QTc, and arrhythmia prevalence) in patients with Graves' disease before and after antithyroid therapy.

METHODS

Seventy-one patients (48 female, and 23 male), of age between 18-50 years (mean±SD: 36.48±12.20) with GD were included in the study. Patients were treated with antithyroid therapy (thioamides and/or surgical therapy) to maintain euthyroid status. Patients were examined in terms of electrocardiographic parameters before and after the treatment.

RESULTS

Mean TSH, free thyroxin (fT4), and tri-iodothyrionine (fT₃) levels of all patients were 0.005±0.21, 3.27± 1.81, 11.42±7.44, respectively. While 9 patients (group 2) underwent surgical therapy, had suspicious malignant nodule or large goiter, and unresponsiveness to medical treatment; the other patients (n=62, group 1) were treated with medical therapy. Patients with surgical therapy had more increased serum fT4 (p=0.045), anti-thyroglobulin value (p=0.018) and more severe graves orbitopathy (n=0.051) before treatment when compared to a medical therapy group. Baseline Tpe duration and baseline Tpe/QTc ratio and frequency of supraventricular ectopic beats were found to be significantly higher in group 2 when compared to group 1 (p=0.00, p=0.005). Otherwise, the baseline mean heart rate, QRS duration, QTc values of both groups were similar. Although the patients came at their euthyroid status, group 2 patients still suffered from more sustained supraventricular ectopics beats than group 1.

CONCLUSION

Distinct from the medical treatment group, surgical treatment group with euthyroidism for at least 3 months still suffered from an arrhythmia (Tpe, Tpe/QTc, supraventricular and ventricular ectopic beats).

Management of Cardiogenic Shock due to Thyrotoxicosis: A Systematic Literature Review

Background

A grave complication of thyrotoxicosis, or thyroid storm, is the development of heart failure and cardiomyopathy. Recognizing this condition is imperative in preventing further left ventricular dysfunction and cardiogenic shock. This manuscript aims to review the literature on cardiogenic shock associated with thyrotoxicosis and present management recommendations on this rare condition.

Methods

A literature search was performed in December of 2018, using the PubMed medical search engine. A systematic search was carried out using the keywords Thyroid Storm AND Cardiogenic Shock and Thyrotoxicosis AND Shock.

Management

Decrease of thyroid hormone levels using therapeutic plasma exchange LV Unloading and ventilation by Impella and Extracorporeal Mechanical Ventilation (ECMO).

Conclusion

Patients presenting with thyroid storm-induced shock may not be suitable candidates for traditional management with β-adrenergic blockers (β-blockers). The use of β-blockers could exasperate their condition. Through extensive literature review on this rare condition, the most effective management was found to be therapeutic plasma exchange in order to decrease thyroid hormone levels, which have direct toxic effect on the heart. Furthermore, the use of ECMO and Impella is advised to reduce pressure on the heart and ensure the patient’s organs are well oxygenated and perfused while the left ventricle is recovering.

VISCERAL AND SUBCUTANEOUS FAT INCREASED AFTER TREATMENT OF GRAVES DISEASE

Objective: Patients with Graves disease (GD) tend to gain weight after treatment, but it remains unknown if weight gain is associated with an increase in the visceral and/or subcutaneous fat areas (VFA, SFA). Methods: We enrolled 25 newly diagnosed GD patients (22 females, median age 33.0 years) and studied their clinical parameters, and VFA and SFA measured by a dual bioelectric impedance analysis. We divided them into 2 groups based on the rates of change in the VFA and SFA, and we compared clinical parameters at the baseline between the groups to evaluate factors that influence increases in the VFA and/or SFA with treatment. Results: The patients' body weight (BW), VFA, and SFA were significantly increased after a 6-month treatment (BW: from 54.3 ± 10.3 kg to 58.0 ± 11.2 kg; P<.001; VFA: from 47.1 ± 21.3 cm² to 54.7 ± 23.4 cm²; P = .004; SFA: from 159.8 ± 85.9 cm² to 182.2 ± 82.9 cm²; P = .008). The percent changes of BW correlated with the SFA (ρ = .591, P = .002), but not with the VFA. The patients with larger VFA increases had significantly less VFA at the baseline compared to those with smaller increases, expressed as median and interquartile range (33.9 cm² [22.7 to 47.5 cm²] versus 54.5 cm² [45.2 to 64.0], respectively; P = .011). A larger increase in the SFA was negatively associated with serum alkaline phosphatase. An increase in the SFA was associated with free triiodothyronine (T3) in a multivariate logistic analysis (odds ratio: 0.80 [0.59 to 0.97]; P = .013). Conclusion: The patients' BW, VFA, and SFA were increased after GD treatment. The increase in SFA seemed to contribute to weight gain and was associated with a low baseline level of free T3. Abbreviations: ALP = alkaline phosphatase; BMI = body mass index; BW = body weight; GD = Graves disease; SFA = subcutaneous fat area; T3 = triiodothyronine; T4 = thyroxine; TG = triglycerides; VFA = visceral fat areas.

[Acute autoimmune myocarditis secondary to Graves' disease: a case report]

INTRODUCTION

Interactions between heart and thyroid are strong. Main cardiac complications of Graves' disease are supra-ventricular tachycardia or high output cardiac failure, without real myocardial involvement.

OBSERVATION

A 40-year-old man with history of refractory Graves' disease was hospitalized for an acute chest pain with elevated cardiac biomarkers and normal coronarography. Acute myocarditis was confirmed by cardiac MRI. We found no evidence for an infectious etiology. We retained the hypothesis of acute autoimmune myocarditis in the context of active Graves' disease.

CONCLUSION

Acute myocarditis is an exceptional complication of Graves' disease, with most likely an autoimmune mechanism. Possible occurrence of fulminant rhythmic or hemodynamic complications justify minimal cardiological check-up before introducing beta blockers.

Thyrotoxicosis-induced cardiomyopathy treated with venoarterial extracorporeal membrane oxygenation

A 37-year-old woman with no past medical history presented with longstanding untreated hyperthyroidism and consequentially developed thyrotoxicosis-induced cardiomyopathy. Upon admission, she was noted with a heart rate of 172 beats per minute and an EKG consistent with supraventricular tachycardia which was unresponsive to adenosine. Shortly after the initiation of a non-cardioselective beta-blocker for the treatment of persistent tachycardia, she developed profound cardiogenic shock refractory to vasopressors and inotropes. She was diagnosed with thyroid storm, which was ultimately attributed to Graves' Disease and controlled with propylthiouracil, potassium iodide drops, and hydrocortisone. Extracorporeal membrane oxygenation (ECMO) was successfully used as a temporizing measure while her thyroid hormone level normalized and cardiac function recovered. Patients with longstanding untreated hyperthyroidism may be dependent on the induced hyperadrenergic state to compensate for low-output cardiac failure, therefore it is important to exercise caution when initiating beta-adrenergic blockade. Given the expected disease time-course in cases of acute decompensation, ECMO remains a viable option for short-term mechanical circulatory support.

Cardiothyreosis: Prevalence and risk factors

Cardiothyreosis (CT) or thyrotoxic heart disease is associated with higher morbidity and mortality than the other forms of hyperthyroidism. Its risk factors have been analyzed in a limited number of studies. The aims of our study were to investigate the prevalence of CT and its risk factors in patients with hyperthyroidism.

METHODS

We identified 538 patients with a hospital discharge diagnosis of hyperthyroidism from January 2000 to December 2015. Among them, 35 patients were diagnosed as having CT. Their demographic, clinical and biological characteristics were studied and compared with those of 72 controls (patients admitted for hyperthyroidism without CT) randomly selected using univariate and multivariate analysis.

RESULTS

The prevalence of CT in patients hospitalized with overt hyperthyroidism was 6.5%. The cardiac complications seen were atrial fibrillation (AF) in 33 cases (6.1%) and cardiac heart failure (CHF) in 11 cases (2%). The risk factors of CT were age greater than 50 years (OR=13.1; 95% CI [4.9-34.4]), low socioeconomic status (OR=2.8; 95% CI [1.2-6.7]), low educational level (OR=3.1; 95% CI [1.2-8.3]), personal history of hypertension (OR=3.5; 95% CI [1.1-11.2]) and a multinodular toxic goiter as the etiology of hyperthyroidism (OR=4.6; 95% CI [1.6-13.9]). After multivariate analysis, age greater than 50 years was the only independent risk factor of CT (adjusted OR=11.6; 95% CI [2.7-49.5]). Severe biological hyperthyroidism (FT4 >3 times normal) was associated with a lower risk of CT (adjusted OR=0.2; 95% CI [0.1-0.9]).

CONCLUSIONS

The prevalence of CT in patients with overt hyperthyroidism was relatively low. Cardiac complications were AF and CHF with a clear predominance of AF. Advanced age was the only independent risk factor of CT. Cardiac complications may be seen even if hyperthyroidism is not biologically severe.

Pattern and Presentation of Thyro-Cardiac Disease among Patients with Hyperthyroidism Attending a Tertiary Hospital in Ethiopia: A Cross Sectional Study

Background

Thyro-cardiac disease describes the existence of a combination of thyroid toxicity and significant heart disease in an individual patient. The frequent manifestations of thyro-cardiac disease are hypertension, atrial flutter or fibrillation, pulmonary hypertension and dilated cardiomyopathy. The aim of the study was to determine the pattern and presentation of cardiovascular diseases in patients with hyperthyroidism on follow-up at St. Paul's Hospital endocrine clinic.

Methods

It was a hospital based cross sectional study that evaluated hyperthyroid patients' on follow-up at St. Paul's Hospital for cardiovascular diseases from May 1^st 2017 to October 31^st 2017. They had focused history, physical examination, electrocardiographic and echocardiographic evaluation.

Results

A total of 146 hyperthyroid patients on follow-up were included in the study. The mean age was 47.2 years and females accounted for 93.2% of patients. The mean duration of symptoms before presentation was 42 months. The frequent causes of hyperthyroidism were toxic multi-nodular goitre (88.4%), Graves' disease (6.8%) and toxic adenoma (2.1%). Sixteen (11%) patients had atrial fibrillation and 71 (48.6%) had hypertension. Thyrocardiac disease was detected in 46.6% of patients. The frequent abnormalities were left ventricular hypertrophy (14.4%), mild diastolic dysfunction (10.9%), moderate to severe mitral regurgitation (8.9%), pulmonary hypertension with or without right ventricular dysfunction (8.2%) and dilated cardiomyopathy (4.1%).

Conclusion

Cardiovascular disease was frequent among patients with hyperthyroidism. The commonest abnormalities were systemic hypertension, pulmonary hypertension with or without isolated right sided heart failure, atrial fibrillation and dilated cardiomyopathy.

Diabetic Ketoacidosis Associated with Thyroxine (T₄) Toxicosis and Thyrotoxic Cardiomyopathy

Thyrotoxicosis and diabetic ketoacidosis (DKA) both may present as endocrine emergencies and may have devastating consequences if not diagnosed and managed promptly and effectively. The combination of diabetes mellitus (DM) with thyrotoxicosis is well known, and one condition usually precedes the other. Furthermore, thyrotoxicosis is complicated by some degree of cardiomyopathy in at least 5% de patients; but the coexistence of DKA, thyroxin (T₄) toxicosis, and acute cardiomyopathy is extremely rare. We describe a case of a man, previously diagnosed with DM but with no past history of thyroid disease, who presented with shock and severe DKA that did not improve despite optimal therapy. The patient evolved with acute pulmonary edema, elevated troponin levels, severe left ventricular systolic dysfunction, and clinical and laboratory evidence of thyroxin (T₄) toxicosis and thyrotoxic cardiomyopathy. Subsequently, the patient evolved favorably with general support and appropriate therapy for DKA and thyrotoxicosis (hydrocortisone, methimazole, Lugol’s solution) and was discharged a few days later.

Thyroid stimulating hormone suppression time on cardiac function of patients with differentiated thyroid carcinoma

Background

This study was to investigate the influence of thyroid stimulating hormone (TSH) suppression time on the cardiac function of differentiated thyroid carcinoma (DTC) patients.

Methods

105 DTC patients were divided into strict TSH suppression group (model group, TSH ≤ 0.1 mU/L) and general TSH suppression group (control group, TSH > 0.1 mU/L). According to the suppression time, these two groups were respectively divided into three groups: group within half a year, group between half a year and a year and group more than a year. Gated myocardial perfusion imaging was applied to observe differences of left ventricle (LV) myocardial perfusion, LV diastolic and systolic function and LV systolic synchrony in every group.

Results

The left ventricular diastolic function, systolic synchrony and myocardial perfusion level of model group decreased with prolonged suppression time. The values of left ventricular EF, PFR and BPM in patients less than half a year were higher than those in 6 months to 1 year for control group.

Conclusion

Thyroid stimulating hormone suppression can influence the cardiac function of patients and with the prolongation of suppression time, regardless of the level of TSH suppression, the possibility of cardiac function depression in patients will increase. TSH may lower the risk of cardiovascular disease in high-risk patients than those in TSH patients with moderate or low risk. The drugs improving cardiac function should be used cooperatively in different suppression period to decrease the occurrence rate of cardiac adverse reactions.

Effects of enteral different-dose levothyroxinesodium pretreatment on serum thyroid hormone levels and myocardial ischemia-reperfusion injury

INTRODUCTION

The available evidence shows that perioperative oral thyroid hormone can significantly attenuate the postoperative decline in the serum hormone level and improve postoperative hemodynamic and prognostic parameters. However, there has been no study assessing the effects of preoperative oral different-dose thyroid hormone on serum hormone levels and myocardial ischemia-reperfusion injury (IRI) after cardiac surgery.

METHODS

Forty-eight healthy Wistar rats, aged 35 days, were randomly allocated into six groups: Group BC, Group C and four pretreatment groups in which the rats were given levothyroxine-sodium of 10 μg, 20 μg, 40 μg and 80 μg/100 g. On the eighth day, the serum thyroid hormone levels were determined and then an isolated heart ischemia-reperfusion model was established with a Langendorff apparatus.

RESULTS

Compared with Groups BC and C, serum thyroid hormone levels on the eighth day did not significantly change in Group 10 μg, but were significantly increased in Groups 20 μg, 40 μg and 80 μg. The cardiac enzyme myocardial-bound creatine kinase levels in the coronary effluent during reperfusion were significantly lower in Groups 10 μg and 20 μg and 40 μg than in Group C. The recovery rates of + dp/dt_max and - dp/dt_max at 30 min during reperfusion were significantly lower in Groups 40 μg and 80 μg than in Groups 10 μg and 20 μg. Compared with Group C, myocardial expressions of heat shock protein 70 and myosin heavy chain α were increased in the four experiment groups and myocardial expression of thyroid hormone receptor α1 was significantly increased in Groups 20 μg, 40 μg and 80 μg.

CONCLUSIONS

The pretreatment with enterally smaller doses levothyroxine-sodium does not significantly affect serum thyroid hormone levels and produces protection against myocardial IRI, whereas pretreatment with enterally larger doses of levothyroxine-sodium can only provide an attenuated or insignificant cardioprotection because of hyperthyroxinemia. Cardioprotection by levothyroxine-sodium pretreatment is probably attributable to increased myocardial expression of heat shock protein 70 and myosin heavy chain α.

Cardiorespiratory Failure in Thyroid Storm: Case Report and Literature Review

Thyroid storm is a potentially fatal manifestation of thyrotoxicosis. Cardiopulmonary failure is the most common cause of death in thyroid storm. Clinicians should keep in mind that thyroid storm complicated with cardiopulmonary failure can be the first presentation of thyrotoxicosis. As early intervention is associated with improved patient outcome, prompt diagnosis based on clinical grounds is of paramount importance in the management of thyrotoxicosis. A high index of suspicion and the ability of early recognition of impending thyroid storm depends on a thorough knowledge of both the typical and atypical clinical features of this illness. Herein, we report a case of thyroid storm presenting as cardiopulmonary failure in a 51-year-old woman with undiagnosed Grave’s disease. Additionally, we review the pathophysiology of cardiopulmonary failure associated with thyrotoxicosis and various treatment modalities for thyroid storm.

Left ventricular functions in children with newly diagnosed Graves' disease. A single-center study from Upper Egypt

This study aimed to evaluate the left ventricular (LV) functions in a cohort of children with Graves' disease (GD). This is a cross-sectional case-control study. It included 36 children with GD and 36 healthy children matched for age and gender. Thyroid hormones (TSH, FT4, and FT3) and anti-thyroid autoantibodies [anti-thyroid peroxidase (anti-TPO), thyrotropin receptor (TRAbs), and thyroglobulin antibodies] were measured. Conventional and tissue Doppler imaging (TDI) echocardiographies were used to assess left ventricular systolic and diastolic functions. LV mass index (LVMI) and myocardial performance index (MPI) were also measured. Compared to healthy children, conventional echocardiography of patients with GD revealed higher LVMI (P = 0.001) indicating LV hypertrophy but normal LV functions while TDI revealed lower Em/Am ratio indicating LV diastolic dysfunction (P = 0.001). Significant correlations were reported between FT4 with LVMI (P = 0.05), Em/Am (P = 0.01), and MPI (P = 0.01). In multivariate analysis, a positive correlation was identified between FT4 with MPI (OR = 1.17; 95% CI = 1.09-1.15; P = 0.001).

CONCLUSIONS

Children with newly diagnosed GD may have significant subclinical changes in LV structure and function (diastolic and global). TDI is more sensitive than conventional Doppler in detecting LV dysfunction. These findings highlight the importance of early monitoring of children with GD for left ventricular mass index and diastolic function. What is Known: • There is an increased risk for cardiac abnormalities in children with Graves' disease (GD). • Limited studies assessed left ventricular function in patients with GD. What is New: • Children with newly diagnosed GD may have significant subclinical changes in left ventricular structure and functions. • Children with newly diagnosed GD should be monitored for left ventricular mass index and diastolic function.

A Combination of Tachycardia-Mediated Heart Failure and Coronary Artery Vasospasm-Induced Silent Myocardial Infarction in a Patient with Severe Thyrotoxicosis

Severe thyrotoxicosis can present with a myriad of cardiovascular complications. It may be mild features such as palpitations, tachycardia, and exertional dyspnea or may progress to life-threatening consequences such as atrial fibrillation, tachyarrhythmias, heart failure, myocardial infarction, and shock. In rare cases, they may present with myocardial ischemia secondary to coronary artery vasospasm. We report a case of a 59-year-old Malay gentleman who presented with fast atrial fibrillation and tachycardia-mediated heart failure that evolved to a silent myocardial infarction secondary to severe coronary artery vasospasm with undiagnosed severe thyrotoxicosis. He had complete resolution of heart failure and no further recurrence of coronary artery vasospasm once treatment for thyrotoxicosis was initiated and euthyroidism achieved. This life-threatening consequence has an excellent prognosis if recognised early and treated promptly.

Thyrotoxic Atrial Fibrillation: Factors Associated with Persistence and Risk of Ischemic Stroke

Background

Atrial fibrillation (AF) is one of the commonest cardiovascular manifestations of thyrotoxicosis. A significant proportion of patients have persistent AF which may have long term consequences, for example, ischemic stroke.

Methods

We performed a retrospective cohort study in a regional hospital from January 2004 to June 2016 to examine the clinical characteristics and outcomes of thyrotoxic patients who presented with atrial fibrillation and to investigate possible factors associated with persistent atrial fibrillation and ischemic stoke.

Results

Among 1918 patients who had a diagnosis of thyrotoxicosis, 133 (6.9%) patients presented with AF. Spontaneous sinus conversion occurred in 89 (66.9%) patients in which 85 (94%) patients developed sinus conversion before or within 6 months after having achieved euthyroidism. The remaining 44 (33.1%) had persistent AF. The rate of ischemic stroke was numerically higher among patients who had persistent AF than those with spontaneous sinus conversion (15.9% versus 10.1%; log-rank 0.442, p = 0.506). Patients who sustained an ischemic stroke were older (71 ± 11 years versus 62 ± 16 years, p = 0.023) and had a trend towards higher CHA₂DS₂-VASc score (2.9 ± 1.7 versus 2.3 ± 1.7, p = 0.153). History of smoking (adjusted odds ratio 4.9, 95% CI [1.8,14.0], p = 0.002), a larger left atrial diameter (adjusted odd ratio 2.6, 95% CI [1.2,5.5], p = 0.014), and a relatively lower free thyroxine level at diagnosis (adjusted odd ratio 2.1, 95% CI [1.2,3.5], p = 0.008) were associated with persistence of AF on multivariate analysis.

Conclusion

Persistence of thyrotoxic AF occurred in one-third of patients and spontaneous sinus conversion was unlikely after six months of euthyroidism. High rate of ischemic stroke was observed among patients with persistent thyrotoxic AF and older age. Patients with factors associated with persistent AF, especially older people, should be closely monitored beyond 6 months so that anticoagulation can be initiated in a timely manner to reduce risk of ischemic stroke.