Severe reversible dilated cardiomyopathy and hyperthyroidism: case report and review of the literature

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.

First Case Report of Arrhythmogenic Right Ventricular Cardiomyopathy Showing Refractory Ventricular Tachycardia Induced by Thyroid Storm due to Graves’ Disease

A 48-year-old man who was diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) due to a plakophilin 2 gene mutation developed acute both-sided heart failure with rapid atrial fibrillation and was hospitalized. After admission, sustained ventricular tachycardia, which was refractory to antiarrhythmic agents, occurred repeatedly, and required electrical cardioversion. He was diagnosed with thyroid storm due to Graves' disease, and treatment for hyperthyroidism was initiated. After the treatment, lethal arrhythmia did not reoccur, and biventricular heart failure ameliorated. To our best knowledge, this is the first report in English of a patient with ARVC showing refractory arrhythmia induced by thyroid storm due to Graves' disease.

Hydrogen Attenuates Thyroid Hormone-Induced Cardiac Hypertrophy in Rats by regulating angiotensin II type 1 receptor and NADPH oxidase 2 mediated oxidative stress

Cardiac hypertrophy occurs as a result of high levels of thyroid hormone, which may contribute to heart failure and is closely related to oxidative stress. Hydrogen is a good antioxidant. In this study, we found that intragastric levothyroxine administration for two weeks caused obvious cardiac hypertrophy without reduced systolic function. Additionally, hydrogen inhalation ameliorated the levothyroxine-induced metabolic increase and cardiac hypertrophy in rats. Serum brain natriuretic peptide expression was also attenuated by hydrogen treatment. However, hydrogen had no significant effect on levothyroxine -induced serum troponin I and serum thyroid hormone changes. Hydrogen treatment also reduced the levothyroxine-induced increase in cardiac malondialdehyde, 8-hydroxy-2-deoxyguanosine and serum hydrogen peroxide levels and upregulated superoxide dismutase and glutathione peroxidase activity. Additionally, western blotting results showed that hydrogen inhalation inhibited the expression of cardiac nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2), angiotensin II type 1 receptor, sarcoplasmic reticulum Ca²⁺-ATPase (SERCA2), phospho-phospholamban and α-myosin heavy chain proteins. In conclusion, the present study revealed a protective effect of hydrogen on levothyroxine -induced cardiac hypertrophy by regulating angiotensin II type 1 receptors and NOX2-mediated oxidative stress in rats.

A Case of Severe Dilated Cardiomyopathy and Hyperthyroidism

Hyperthyroidism often leads to heart failure when left untreated, specifically high output heart failure and left ventricular (LV) hypertrophy. A very minimal portion of those develop severe LV dysfunction. We report a case of a 65-year-old male who presented with signs and symptoms of heart failure and was found to have hyperthyroidism, severe systolic dysfunction, and severe dilated cardiomyopathy.

The patient is a 65-year-old African American male with a history of hypertension (HTN) who presented with complaints of dyspnea on exertion and bilateral lower limb edema of one-week duration. A review of systems revealed paroxysmal nocturnal dyspnea, orthopnea, palpitations, fatigue, and weight loss. Physical exam showed tachycardia but otherwise no exophthalmos, no thyromegaly, no thyroid nodules, clear lungs, normal heart sounds, regular heart rhythm, normal reflexes, and 2+ edema of bilateral lower extremities up to the knees. Labs showed elevated B-natriuretic peptide, severely suppressed thyroid-stimulating hormone, elevated free triiodothyronine (FT3), and free thyroxine (FT4). Electrocardiogram (EKG) revealed sinus tachycardia, incomplete left bundle branch block, and non-specific T wave abnormality. Echocardiography revealed abnormal (LV) structure and function, with moderate to severe dilatation without LV hypertrophy, severe LV systolic dysfunction with ejection fraction (EF) 30-35%, and an abnormal LV diastolic function.

The patient was managed with diuresis for acute onset heart failure and with beta-blocker and methimazole for symptomatic hyperthyroidism.

Thyroid assessment is an important step in evaluating any patient with suspected heart failure. This case highlights the balance that should exist between treating hyperthyroidism symptoms and managing disease states such as acute heart failure.

Dome-and-dart T Waves and Hyperthyroidism - A Case Report

We briefly describe a case of a 31-year-old man with persistent hyperthyroidism, despite medical treatment with high dose methimazole. Twelve-lead 24-hour Holter monitoring showed bifid (or dome-and-dart) T waves and echocardiography revealed mild left ventricle dilatation. Hyperthyroidism was eventually treated with total thyroidectomy, and thereafter, T waves became normal and the left ventricle returned to normal dimensions. Hyperthyroidism should be considered among the differential diagnoses when T wave abnormalities are observed on electrocardiogram and when mild left ventricle dilatation is observed on an echocardiogram. The correction of hyperthyroidism can reverse these abnormalities.

Impact of surgery versus medical management on cardiovascular manifestations in Graves disease

BACKGROUND

Graves disease is well known to have multiple adverse effects on the cardiovascular system. We compared the cardiovascular outcomes after surgical intervention versus medical treatment in patients with Graves disease.

METHODS

We performed a retrospective study of all Graves disease patients with a cardiovascular comorbidity who underwent either surgical or medical management (N = 151). Perioperative biochemical and cardiovascular outcomes from the surgical versus the medical groups were analyzed.

RESULTS

Of 151 patients, 69 (45.6%) patients underwent total thyroidectomy and 82 (54.3%) patients received medical treatment. Hypertension resolved in 44.7% of the patients from the surgical group vs 18% in the medical group (P = .03). Tachyarrhythmias, including atrial fibrillation and tachycardia, improved in 85.9% of patients in the surgical group vs 66% in the medical group (P = .01). All cardiovascular manifestations examined, hypertension, tachyarrhythmias, and heart failure, improved in 69% of patients in the surgical group and 42.6% of patients in the medical group during the follow-up period (P < .01).

CONCLUSION

Surgical treatment offers a significant and rapid clinical improvement of cardiovascular manifestations in Graves disease patients, such as hypertension, tachyarrhythmias, and heart failure. Surgery should be considered and recommended in Graves disease patients with known cardiovascular manifestations.

Impact of hyperthyroidism on cardiac hypertrophy

The cardiac growth process (hypertrophy) is a crucial phenomenon conserved across a wide array of species and it is critically involved in maintenance of cardiac homeostasis. This process enables organism adaptation to changes of systemic demand and occurs due to a plethora of responses, depending on the type of signal or stimuli received. The growth of cardiac muscle cells in response to environmental conditions depends on the type, strength and duration of stimuli, and results in adaptive physiologic response or non-adaptive pathologic response. Thyroid hormones (TH) have a direct effect on the heart and induce a cardiac hypertrophy phenotype, which may evolve to heart failure. In this review, we summarize the literature on TH function in heart presenting results from experimental studies. We discuss the mechanistic aspects of TH associated with cardiac myocyte hypertrophy, increased cardiac myocyte contractility and electrical remodeling as well as the signaling pathways associated. In addition to classical crosstalk with the Sympathetic Nervous System (SNS), emerging work points to the new endocrine interaction between TH and Renin-Angiotensin System (RAS) is also explored. Given the inflammatory potential of the angiotensin II peptide, this new interaction may open the door for new therapeutic approaches that target key mechanisms responsible for TH-induced cardiac hypertrophy.

[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.

Evaluation of the Cardiac Morphologic Alterations Secondary to Autoimmune Thyroid Disorder Using Cardiac Magnetic Resonance Imaging

Purpose:

Thyroid functional disease is associated with clinically significant cardiovascular changes. The aim of this study was to assess changes in the cardiac magnetic resonance imaging of patients with autoimmune thyroid disorders (AITs).

Materials and Methods:

Forty patients with AIT (12 men, 28 women; age range, 20 to 82 y; mean age, 59 y) were identified and included in our study. In addition, 20 controls (12 men, 8 women; age range, 21 to 76 y; mean age, 50 y) without AIT or cardiac disorders were included.

Results:

In patients with AIT, the mean value calculated for the end diastolic volume was 161.2 mL, the mean end systolic volume value was 95.3 mL, and the mean left ventricular ejection fraction value was 45.2%. In comparing AIT patients with the control group, we found a significant difference in the end systolic volume, ejection fraction, stroke index, cardiac output, cardiac index, and left ventricular diameter (P<0.05).

Conclusions:

We conclude that our data show that there is a correlation between thyroid function and cardiac function, as evaluated with cardiac magnetic resonance imaging. This can be useful in the diagnosis of cardiovascular changes associated with AIT.

Propranolol-Induced Circulatory Collapse in a Patient With Thyroid Crisis and Underlying Thyrocardiac Disease: A Word of Caution

Thyrotoxic crisis or thyroid storm is a severe form of hyperthyroidism and a rare endocrinological emergency. The cornerstones of medical therapy in thyroid storm include decreasing the levels of circulating T3 in the blood as well as inhibiting the hormone's peripheral effects through β-adrenergic blockade. Propranolol is the preferred agent for β-blockade in hyperthyroidism and thyroid storm due to its additional effect of blocking the peripheral conversion of inactive T4 to active form T3. We report a typical clinical scenario where propranolol was administered in treatment of thyroid storm but an uncommon adverse outcome: circulatory failure from cardiogenic shock warranting vasopressor and inotropic support. Caution with regard to the use long-acting β-blocking agents in patients with underling thyrocardiac disease may prevent this life-threatening adverse effect. Ultra-short-acting β-blockers that are easy to titrate maybe a suitable alternative in this subset of patients.

COMPARISON OF CARDIAC ARRHYTHMIA TYPES BETWEEN HYPERTHYROID PATIENTS WITH GRAVES' DISEASE AND TOXIC NODULAR GOITER

Purpose

Previous studies have demonstrated the relationship between hyperthyroidism and increased risk of cardiac arrhythmias. The most common causes of hyperthyroidism are Graves' disease (GD) and toxic nodular goiter (TNG). The aim of our study was to demonstrate if the underlying mechanism of hyperthyroidism, in other words autoimmunity, has an impact on the type of cardiac arrhythmias accompanying hyperthyroidism.

Method

Twenty patients with TNG and 16 patients with GD who had overt hyperthyroidism were included in the study. Age, sex, thyroid hormone levels, thyroid autoantibody positivity, thyroid ultrasonography and scintigraphy results were recorded. 24-hour Holter ECG monitoring was performed in all patients.

Results

Mean age was significantly higher in the TNG group compared to the GD group (62.9±11.5 vs. 48.9±8.6 years, p=0.001). Free T3 was significantly higher (7.87±3.90 vs. 5.21±1.53 pg/mL, p=0.033) in the GD group while free T4 and TSH levels were similar between the two groups. In 24-hour Holter ECG recordings nonsustained ventricular tachycardia (VT) rates were significantly higher in the GD group than in TNG group [18.75% (n=3/16) vs. 0% (n=0/20), respectively, (p=0.043)]. Paroxysmal atrial fibrillation (AF) rates were significantly higher in the TNG group compared to GD group [(30% (n=6/20) vs. 0% (n=0/16), respectively, (p=0.016)].

Conclusion

Although free T3 levels were lower, paroxysmal AF rates were found significantly higher in the TNG group which may be associated with significantly higher age of this group. On the other hand, higher rate of nonsustained VT in the GD group may be related to either significantly higher free T3 levels or autoimmunity.

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.

Dilated cardiomyopathy with Graves disease in a young child

Graves disease (GD) can lead to complications such as cardiac arrhythmia and heart failure. Although dilated cardiomyopathy (DCMP) has been occasionally reported in adults with GD, it is rare in children. We present the case of a 32-month-old boy with DCMP due to GD. He presented with irritability, vomiting, and diarrhea. He also had a history of weight loss over the past few months. On physical examination, he had tachycardia without fever, a mild diffuse goiter, and hepatomegaly. The chest radiograph showed cardiomegaly with pulmonary edema, while the echocardiography revealed a dilated left ventricle with an ejection fraction (EF) of 28%. The thyroid function test (TFT) showed elevated serum T3 and decreased thyroid stimulating hormone (TSH) levels. The TSH receptor autoantibody titer was elevated. He was diagnosed with DCMP with GD; treatment with methylprednisolone, diuretics, inotropics, and methimazole was initiated. The EF improved after the TFT normalized. At follow-up several months later, although the TFT results again showed evidence of hyperthyroidism, his EF had not deteriorated. His cardiac function continues to remain normal 1.5 months after treatment was started, although he still has elevated T3 and high TSH receptor antibody titer levels due to poor compliance with drug therapy. To summarize, we report a young child with GD-induced DCMP who recovered completely with medical therapy and, even though the hyperthyroidism recurred several months later, there was no relapse of the DCMP.

Thyroid hormones and the heart

Thyroid hormones have a significant impact on heart function, mediated by genomic and non-genomic effects. Consequently, thyroid hormones deficit as well as excess are expected to result in profound changes in cardiac function regulation and cardiovascular hemodynamics. Thyroid hormones upregulate the expression of the sarcoplasmic reticulum calcium-activated ATPase and downregulate the expression of phospholamban. Overall, hyperthyroidism is characterized by an increase in resting heart rate, blood volume, stroke volume, myocardial contractility, and ejection fraction. The development of "high-output heart failure" in hyperthyroidism may be due to "tachycardia-mediated cardiomyopathy." In contrast, in the hypothyroid state, thyroid hormone deficiency results in lower heart rate and weakening of myocardial contraction and relaxation, with prolonged systolic and early diastolic times. Cardiac preload is decreased owing to impaired diastolic function, cardiac afterload is increased, and chronotropic and inotropic functions are reduced. Subclinical thyroid dysfunction is relatively common in patients >65 years of age. In general, subclinical hypothyroidism increases the risk of cardiovascular heart disease (CHD) mortality and CHD events, but not of total mortality. The risk of CHD mortality and atrial fibrillation (but not other outcomes) in subclinical hyperthyroidism is higher among patients with very low levels of thyrotropin. Finally, medications such as amiodarone may induce hypothyroidism (mediated by the Wolff-Chaikoff effect) as well as hyperthyroidism (mediated by the Jod-Basedow effect). In both instances, the underlying cause is the high concentration of iodine in this medication. The purpose of this review is to assess the effects of thyroid hormones on the heart, and their clinical repercussions.

Thyroid Storm with Heart Failure Treated with a Short-acting Beta-adrenoreceptor Blocker, Landiolol Hydrochloride

Beta-adrenoreceptor blockers are essential in controlling the peripheral actions of thyroid hormones and a rapid heart rate in patients with thyroid storm, although they should be used with great caution when there is the potential for heart failure. A 67-year-old woman was diagnosed as having thyroid storm in addition to marked tachycardia with atrial fibrillation and heart failure associated with a reduced left ventricular function. The administration of an oral beta blocker, bisoprolol fumarate, induced hypotension and was not tolerable for the patient, whereas landiolol hydrochloride, a short-acting intravenous beta-adrenoreceptor blocker with high cardioselectivity and a short elimination half-life, was useful for controlling the patient's tachycardia and heart failure without causing hemodynamic deterioration.

Effects of thyroid hormones on the heart

Thyroid hormones have a significant impact on heart function, mediated by genomic and non-genomic effects. Consequently, thyroid hormone deficiencies, as well as excesses, are expected to result in profound changes in cardiac function regulation and cardiovascular hemodynamics. Thyroid hormones upregulate the expression of the sarcoplasmic reticulum calcium-activated ATPase and downregulate the expression of phospholamban. Overall, hyperthyroidism is characterized by an increase in resting heart rate, blood volume, stroke volume, myocardial contractility, and ejection fraction. The development of "high-output heart failure" in hyperthyroidism may be due to "tachycardia-mediated cardiomyopathy". On the other hand, in a hypothyroid state, thyroid hormone deficiency results in lower heart rate and weakening of myocardial contraction and relaxation, with prolonged systolic and early diastolic times. Cardiac preload is decreased due to impaired diastolic function. Cardiac afterload is increased, and chronotropic and inotropic functions are reduced. Subclinical thyroid dysfunction is relatively common in patients over 65 years of age. In general, subclinical hypothyroidism increases the risk of coronary heart disease (CHD) mortality and CHD events, but not of total mortality. The risk of CHD mortality and atrial fibrillation (but not other outcomes) in subclinical hyperthyroidism is higher among patients with very low levels of thyrotropin. Finally, medications such as amiodarone may induce hypothyroidism (mediated by the Wolff-Chaikoff), as well as hyperthyroidism (mediated by the Jod-Basedow effect). In both instances, the underlying cause is the high concentration of iodine in this medication.

Graves' thyrotoxicosis-induced reversible cardiomyopathy: a case report

The objective of this report is to present a case of Graves' thyrotoxicosis-induced cardiomyopathy. This is a case of a 26 year old woman that presented with severe symptomatic congestive heart failure and was subsequently diagnosed with dilated cardiomyopathy secondary to Graves' disease. Despite an initial left ventricular systolic ejection fraction of 20% on echocardiography, treatment with anti-thyroid agents led to rapid improvement of her clinical status and normalization of her ejection fraction. The proposed mechanisms underlying the development of systolic dysfunction in thyrotoxicosis are discussed and the literature on similar cases previously reported is highlighted. Cardiomyopathy should be considered even in young patients with Graves' thyrotoxicosis.

Mechanisms in endocrinology: Heart failure and thyroid dysfunction

CONTEXT

Heart failure (HF) is a major cause of morbidity and mortality in Europe and in the United States. The aim of this review article was to assess the results of the prospective studies that evaluated the risk of HF in patients with overt and subclinical thyroid disease and discuss the mechanism of this dysfunction.

EVIDENCE ACQUISITION

Reports published with the following search terms were searched:, thyroid, hypothyroidism, hyperthyroidism, subclinical hyperthyroidism, subclinical hypothyroidism, levothyroxine, triiodothyronine, antithyroid drugs, radioiodine, deiodinases, clinical symptoms, heart rate, HF, systolic function, diastolic function, systemic vascular resistance, endothelial function, amiodarone and atrial fibrillation. The investigation was restricted to reports published in English.

EVIDENCE SYNTHESIS

The outcome of this analysis suggests that patients with untreated overt thyroid dysfunction are at increased risk of HF. Moreover, persistent subclinical thyroid dysfunction is associated with the development of HF in patients with serum TSH <0.1 or > 10 mU/l.

CONCLUSIONS

The timely recognition and effective treatment of cardiac symptoms in patients with thyroid dysfunction is mandatory because the prognosis of HF may be improved with the appropriate treatment of thyroid dysfunction.

Thyroid storm and reversible thyrotoxic cardiomyopathy after ingestion of seafood stew thought to contain marine neurotoxin

BACKGROUND

Thyroid storm and severe decompensated thyrotoxicosis are life-threatening diseases, requiring immediate treatment in an intensive care unit. Thyrotoxic heart disease is common in patients with hyperthyroidism; thyrotoxic cardiomyopathy with poor left ventricular systolic function is rare. Here, we report a patient who presented with severe decompensated thyrotoxicosis and reversible thyrotoxic cardiomyopathy after ingestion of a mixed seafood stew thought to contain tetrodotoxin or a related marine neurotoxin.

SUMMARY

The patient was a 50-year-old woman who was seen at the emergency room of another hospital with altered mentality and flaccid quadriplegia after eating a mixed seafood stew. At the other hospital, she was diagnosed as having tetrodotoxin intoxication on the basis of her clinical presentation. The patient was placed on assisted ventilation and transferred to our hospital the following day because of persisting fever, tachycardia, and respiratory depression. Upon admission, thyroid storm was diagnosed on the basis of thyroid function tests (total triiodothyronine was 354 ng/dL, free thyroxine was 3.45 ng/dL, and thyroid-stimulating hormone was <0.01 mU/L) and clinical manifestations. On the third hospital day, she complained of chest discomfort and progressively worsening dyspnea. Echocardiography showed reduced left ventricular systolic function (left ventricular ejection fraction, 47%; left ventricular fractional shortening, 24.4%) with regional wall motion abnormality of anteroseptal wall and apex and diastolic dysfunction (grade 1, relaxation abnormality), suggesting thyrotoxic cardiomyopathy. She was treated with 10 mCi of radioactive iodine and methimazole, and her thyroid and cardiac function normalized.

CONCLUSION

The patient reported here developed thyroid storm and cardiac decompensation shortly after a clinical event consistent with ingestion of marine neurotoxin. This adds to the list of stresses that have been associated with thyroid storm and emphasizes the need to fully evaluate patients who, on initial evaluation, appear to have only a single disorder.

A case of thyroid storm with multiple organ failure effectively treated with plasma exchange

We describe a 48-year-old man with thyroid storm presenting with heart failure. He presented severely impaired left ventricular wall motion and a marked increase in the liver enzymes. He developed disseminated intravascular coagulation on day 2. Due to elevated serum thyroid hormone level, anti-thyroid hormone receptor antibody positivity, and his clinical symptoms, he was diagnosed as thyroid storm due to untreated Graves' disease. His condition did not improve even after 6 days of conventional therapy including steroids. After therapeutic plasma exchange was carried out, his thyroid hormone level decreased markedly. Consequently, his condition recovered gradually, and he was discharged at day 43.

Cardiovascular involvement in patients with different causes of hyperthyroidism

Various clinical disorders can cause hyperthyroidism, the effects of which vary according to the patient's age, severity of clinical presentation and association with other comorbidities. Hyperthyroidism is associated with increased morbidity and mortality from cardiovascular disease, although whether the risk of specific cardiovascular complications is related to the etiology of hyperthyroidism is unknown. This article will focus on patients with Graves disease, toxic adenoma and toxic multinodular goiter, and will compare the cardiovascular risks associated with these diseases. Patients with toxic multinodular goiter have a higher cardiovascular risk than do patients with Graves disease, although cardiovascular complications in both groups are differentially influenced by the patient's age and the cause of hyperthyroidism. Atrial fibrillation, atrial enlargement and congestive heart failure are important cardiac complications of hyperthyroidism and are prevalent in patients aged > or = 60 years with toxic multinodular goiter, particularly in those with underlying cardiac disease. An increased risk of stroke is common in patients > 65 years of age with atrial fibrillation. Graves disease is linked with autoimmune complications, such as cardiac valve involvement, pulmonary arterial hypertension and specific cardiomyopathy. Consequently, the etiology of hyperthyroidism must be established to enable correct treatment of the disease and the cardiovascular complications.

[Cardiothyrotoxicosis in the young adult in Marrakech. A report of 36 cases]

Thyrotoxicosis is underdiagnosed because of its low occurrence in series from Africa. The aim of this study was to evaluate the frequency, the demographic data, and the etiological aspects of thyrotoxicosis among hyperthyroidy. Thirty-six patients with thyrotoxicosis (group I) gathered during a period of four years was analysed, as well as 180 hyperthyroidy cases (group II). Cardiothyrotoxicosis was observed with a frequency of 16.6%. The mean age was respectively of 44.5+/-13.3 versus 32.8+/-11.4 years (p<10(-6)). Cardiothyrotoxicosis was related to multinodular goitres (18 cases), a Basedow disease (14 cases), a toxic adenoma (four cases), while the principal cause of hyperthyroidy was toxic adenoma followed by the Basedow disease (72 cases, 40%). Different modes of presentation of cardiothyrotoxicosis were found: cardiac heart failure in 27 cases (75%), permanent atrial fibrillation in 22 cases (61.1%), atrial flutter in two cases, coronary insufficiency in four cases, ventricular extrasystoli (trigeminism) in two cases, second auriculoventricular block in two cases, dilated myocardiopathy in 10 cases (27.7%), ischemic myocardiopathy in four cases, severe mitral regurgitation in one case. This study confirms the relative frequency of cardiothyrotoxicosis, the proportionally weak place of Basedow disease among hyperthyroidy's causes, and role of associated cardiac disease to the hyperthyroid.

Cardiac hypertrophy and thyroid hormone signaling

Thyroid hormone exerts a large number of influences on the cardiovascular system. Increased thyroid hormone action increases the force and speed of systolic contraction and the speed of diastolic relaxation and these are largely beneficial effects. Furthermore, thyroid hormone has marked electrophysiological effects increasing heart rate and the propensity for atrial fibrillation and these effects are largely mal-adaptive. In addition, thyroid hormone markedly increases cardiac angiogenesis and decreases vascular tone. These multiple thyroid hormone effects are largely mediated by the action of nuclear based thyroid hormone receptors (TR) the thyroid hormone receptor alpha and beta. TRα is the predominant isoform in the heart. Rapid nongenomic thyroid hormone effects also occur, which can be clearly demonstrated in ex-vivo experiments. Some of the most marked thyroid hormone effects in cardiac myocytes involve influences on calcium flux, with thyroid hormone promoting expression of the gene encoding the calcium pump of the sarcoplasmic reticulum (SERCa2). In contrast, in hypothyroid animals phospholamban levels, which inhibit the SERCa2 pump, are increased. In addition, marked effects are exerted on the calcium channel of the sarcoplasmic reticulum the ryanodine channel. Related to myofibrillar proteins, myosin heavy chain alpha is increased by T3 and MHC beta is decreased. Complex and interesting interactions occur between cardiac hypertrophy induced by excess thyroid hormone action and cardiac hypertrophy occurring with heart failure. The thyroid hormone mediated cardiac hypertrophy in its initial phases presents a physiological hypertrophy with increases in SERCa2 levels and decreased expression of MHC beta. In contrast, pressure overload induced heart failure leads to a “pathological” cardiac hypertrophy which is largely mediated by activation of the calcineurin system and the MAPkinases signaling system. Recent evidence indicates that heart failure can lead to a downregulation of the thyroid hormone signaling system in the heart. In the failing heart, decreases of thyroid hormone receptor levels occur. In addition, serum levels of T4 and T3 are decreased with heart failure in the frame of the non-thyroidal illness syndrome. The decrease in T3 serves as an indicator for a bad prognosis in the heart failure patient being linked to increased mortality. In animal models, it can be shown that in pressure overload-induced cardiac hypertrophy a decrease of thyroid hormone receptor levels occurs. Cardiac function can be improved by increasing expression of thyroid hormone receptors mediated by adeno-associated virus based gene transfer. The failing heart may develop a “hypothyroid” status contributing to diminished cardiac contractile function.

Incidence, clinical characteristics and outcome of congestive heart failure as the initial presentation in patients with primary hyperthyroidism

BACKGROUND

There are limited systematic data on the incidence, clinical characteristics and outcomes of congestive heart failure (CHF) in patients with hyperthyroidism. The aim of this study was to investigate the incidence, clinical characteristics and outcome of CHF as the initial presentation in patients with primary hyperthyroidism.

METHODS

The prevalence, clinical characteristics and outcome of CHF was studied in 591 consecutive patients (mean (SD) age 45 (1) years, 140 men) who presented with primary hyperthyroidism.

RESULTS

CHF was the presenting condition in 34 patients (5.8%) with hyperthyroidism. The presence of atrial fibrillation at presentation (OR 37.4, 95% CI 9.72 to 144.0, p<0.001) was an independent predictor for the occurrence of CHF. Of the 34 patients with CHF, 16 (47%) had systolic left ventricular dysfunction with left ventricular ejection fraction (LVEF)<50%. They were predominantly male (OR 26.6, 95% CI 2.6 to 272.5, p = 0.006) and had a lower serum thyroxine level (OR 0.93, 95% CI 0.87 to 0.99, p = 0.044) than patients with preserved left ventricular systolic function. In these patients, LVEF (55 (4)% vs 30 (2)%, p<0.001) and New York Heart Association functional class (1.2 (0.1) vs 2.5 (0.2), p<0.001) improved significantly 3 months after achieving euthyroid status. Systolic left ventricular dysfunction (mean (SD) LVEF 38 (4)%) persisted on long-term follow-up in five

PATIENTS

no clinical parameter could be identified to predict the occurrence of this persistent cardiomyopathy (p>0.05).

CONCLUSION

CHF was the initial clinical presentation in approximately 6% of patients with hyperthyroidism, and half of them had left ventricular systolic dysfunction. Symptoms of CHF subsided and LVEF improved after treatment for hyperthyroidism. Nonetheless, one-third of these patients developed persistent dilated cardiomyopathy.

Thyrotoxicosis—an uncommon cause of heart failure

A 26-year-old man presented with high output heart failure and severe systolic left ventricular dysfunction. The underlying cause was determined to be thyrotoxicosis. With aggressive treatment of the hyperthyroid state, near-normalization of the patient's left ventricular systolic function was achieved. Unfortunately, he succumbed to pancreatitis, followed by multiple ICU complications. A brief review of the literature is provided.

B-type natriuretic peptide in patients with clinical hyperthyroidism

AIMS

To investigate the level and clinical significance of plasma B-type natriuretic peptide (BNP) in patients with hyperthyroidism.

METHODS

Plasma BNP was measured in 32 healthy subjects and 67 patients with clinical hyperthyroidism. Left ventricular anatomy and function was assessed with echocardiography.

RESULTS

The average BNP in hyperthyroid patients was higher than that in healthy subjects (186+/-140 vs 34+/-17 ng/l, p =0.001). The increase in BNP was mainly found in hyperthyroid patients who had clinical and echocardiographic evidence of left ventricular dysfunction (250+/-190 ng/l). The BNP level in patients with hyperthyroidism, but with normal left ventricular function, was similar to that of the controls (37+/-17 vs 34+/-17, ng/l, p>0.05). Multi-regression analysis showed that left atrial diameter and left ventricular ejection fraction were independently associated with the plasma levels of BNP.

CONCLUSIONS

there is a significant elevation in plasma BNP in patients with hyperthyroidism; the increase is largely due to hyperthyroidism-induced left ventricular dysfunction. Measurements of plasma BNP may help to detect heart failure in patients with clinical hyperthyroidism.