Hyperthyroidism-induced left ventricular diastolic dysfunction: implication in hyperthyroidism-related heart failure

The association between TSH and thyroid hormones in the normal or subclinical dysfunction range with left ventricular diastolic dysfunction

Thyroid hormones modulate the cardiovascular system. However, the effects of subclinical thyroid dysfunction and euthyroidism on cardiac function remain unclear. We investigated the association between left ventricular (LV) diastolic dysfunction and subclinical thyroid dysfunction or thyroid hormones within the reference range. This cross-sectional study included 26,289 participants (22,197 euthyroid, 3,671 with subclinical hypothyroidism, and 421 with subclinical thyrotoxicosis) who underwent regular health check-ups in the Republic of Korea. Individuals with thyroid stimulating hormone (TSH) levels > 4.2 µIU/mL and normal free thyroxine (FT4, 0.78-1.85 ng/dL) and triiodothyronine (T3, 76-190 ng/dL) levels were defined as having subclinical hypothyroidism. Individuals with serum TSH levels < 0.4 µIU/mL and normal FT4 and T3 levels were defined as having subclinical thyrotoxicosis. The cardiac structure and function were evaluated using echocardiography. LV diastolic dysfunction with normal ejection fraction (EF) was defined as follows: EF of > 50% and (a) E/e' ratio > 15, or (b) E/e' ratio of 8-15 and left atrial volume index ≥ 34 mL/m2. Subclinical hypothyroidism was significantly associated with cardiac indices regarding LV diastolic dysfunction. The odds of having LV diastolic dysfunction was also increased in participants with subclinical hypothyroidism (adjusted odds ratio [AOR] 1.36, 95% confidence interval [CI], 1.01-1.89) compared to euthyroid participants. Subclinical thyrotoxicosis was not associated with LV diastolic dysfunction. Among the thyroid hormones, only serum T3 was significantly and inversely associated with LV diastolic dysfunction even within the normal range. Subclinical hypothyroidism was significantly associated with LV diastolic dysfunction, whereas subclinical thyrotoxicosis was not. Serum T3 is a relatively important contributor to LV diastolic dysfunction compared to TSH or FT4.

Impact of Hemodialysis on Left Ventricular-Arterial Coupling in End-Stage Renal Disease Patients

INTRODUCTION

As a key determinant of cardiovascular performance, vascular-arterial coupling (VAC) has been reported to be a predictor of clinical outcomes in various clinical scenarios. However, few studies have explored how acute fluid removal during hemodialysis (HD) impacts the interaction between cardiac function and the arterial system.

METHODS

We recruited 317 HD patients from an established renal dialysis unit for this cross-sectional study and a total of 285 were included in the final analyses. We measured left ventricle end-systolic elastance (Ees), the effective arterial elastance (Ea), and VAC before and after HD using noninvasive echocardiographic measurements. We also compared echocardiographic and hemodynamic parameters in ventriculo-arterial coupling and ventriculo-arterial uncoupling patients.

RESULTS

HD significantly altered partial ventricular and vascular function parameters such as blood pressure, left ventricular end-diastolic volume, stroke volume, left ventricular ejection fraction, and systemic vascular resistance index. Ea increased following HD from 3.5 ± 1.4 to 4.2 ± 1.8 mm Hg/mL (p < 0.0001), Ees increased following HD from 7.9 ± 5.5 to 9.2 ± 6.9 mm Hg/mL (p = 0.04), whereas VAC did not markedly alter as a result of HD. Ventriculo-arterial uncoupling was found to be related to abnormal cardiac structure and worse systolic function.

CONCLUSIONS

VAC obtained from echocardiography is likely to be load-independent and useful as a reliable index for stratifying the risk of cardiovascular diseases in HD patients. Further investigations on larger patient cohorts are needed to further validate our findings.

Anomalies cardiaques associées à l'hyperthyroïdie : étude clinique, structurelle et rythmique

INTRODUCTION

The prevalence and nature of cardiac complications associated with hyperthyroidism vary considerably in the literature depending on the population studied and the means of investigation used to detect them. The aim of this study was to determine the structural, functional, and rhythmic cardiac abnormalities associated with hyperthyroidism and to identify their risk factors.

METHODS

It is a cross-sectional study conducted in thirty adult patients with overt or subclinical hyperthyroidism. Each patient underwent a clinical cardiovascular examination, a cardiac Doppler ultrasound, a pulmonary ultrasound and a 24-hours rhythm holter. The diagnosis of cardiothyreosis (thyrotoxic heart disease) was retained if an arrhythmia, heart failure (HF) and/or pulmonary arterial hypertension (PAH) were noted following the investigations carried out.

RESULTS

The mean age of the patients was 44.8 ± 14.4 years. The sex ratio (M/F) was 0.3. Five patients (17%) had subclinical hyperthyroidism and 25 (83%) had overt hyperthyroidism. Thirteen patients (43%) had cardiothyreosis. It consisted of a rhythm disorder in three patients (10%), PAH in twelve patients (40%) and HF in eight patients (27%). An age over 50 years and toxic nodular etiology were associated with atrial fibrillation (AF), p = 0.041 and p = 0.004 respectively. Tachycardia and a higher number of atrial extrasystoles were associated with HF, p = 0.039 and p = 0.007 respectively. A lower TSH, tachycardia and a higher number of atrial extrasystoles were associated with the presence of PAH, p = 0.004, p = 0.011 and p = 0.007 respectively.

CONCLUSION

Cardiac complications should be sought in all patients with hyperthyroidism, especially in elderly and tachycardic patients. Specialized investigations such as echocardiography or 24 hours rhythmic holter should be requested in these cases.

Incidence, risk factors, natural history and outcomes of heart failure in patients with Graves' disease

OBJECTIVE

Graves' disease (GD) can both aggravate pre-existing cardiac disease and cause de novo heart failure (HF), but large-scale studies are lacking. We aimed to investigate the incidence, risk factors and outcomes of incident GD-related HF.

METHODS

Patients with GD (2009-2019) were retrospectively included. HF with reduced ejection fraction (HFrEF) was defined by left ventricular ejection fraction <50% and Framingham criteria, while HF with preserved ejection fraction (HFpEF) was defined according to the HFA-PEFF criteria. HF due to ischaemia, valve disorder or other structural heart disease was excluded. Proportional hazards regression was used to analyse risk factors and outcomes.

RESULTS

Of 1371 patients with GD, HF occurred in 74 (5.4%) patients (31 (2.3%) HFrEF; 43 (3.1%) HFpEF). In HFrEF, atrial fibrillation (AF) (HR 10.5 (3.0-37.3), p<0.001) and thyrotropin receptor antibody (TRAb) level (HR 1.05 (1.01-1.09) per unit, p=0.007) were independent risk factors. In HFpEF, the independent risk factors were chronic obstructive pulmonary disease (HR 7.2 (3.5-14.6), p<0.001), older age (HR 1.5 (1.2-2.0) per 10 years, p=0.001), overt hyperthyroidism (HR 6.4 (1.5-27.1), p=0.01), higher body mass index (BMI) (HR 1.07 (1.03-1.10) per unit, p=0.001) and hypertension (HR 3.1 (1.3-7.2), p=0.008). The risk of cardiovascular hospitalisations was higher in both HFrEF (HR 10.3 (5.5-19.4), p<0.001) and HFpEF (HR 6.7 (3.7-12.2), p<0.001). However, only HFrEF was associated with an increased risk of all-cause mortality (HR 5.17 (1.3-19.9), p=0.02) and ventricular tachycardia/fibrillation (HR 64.3 (15.9-259.7), p<0.001).

CONCLUSION

De novo HF occurs in 5.4% of patients with GD and is associated with increased risk of cardiovascular hospitalisations and mortality. Risk factors include AF, higher TRAb, higher BMI and overt hyperthyroidism.

Thyroid Hormones within the Normal Range and Cardiac Function in the General Population: The EPIPorto Study

BACKGROUND

Hypothyroidism and hyperthyroidism are associated with marked changes in cardiac structure and function. However, the association of thyroid function within the normal range with cardiac structure and function in the general population remains uncertain.

METHODS

Eight hundred thirty-five subjects aged ≥45 years from the EPIPorto cohort (evaluation between 2006 and 2008) were cross-sectionally analyzed. We excluded participants with TSH, free T4 (FT4), or free T3 (FT3) outside of the reference range or with self-reported cardiovascular or thyroid disease. Cardiac structure and function were evaluated by echocardiography. We used linear regression models unadjusted and adjusted for sex and age (model 1), and sex, age, BMI, diabetes, hypertension, and smoking (model 2). Nonlinear associations were assessed using restricted cubic splines.

RESULTS

The mean age was 61.5 years (SD 10.5); 61.1% of the patients were women. In the adjusted model 2, heart rate was positively associated with FT3; diastolic blood pressure was positively associated with TSH; LV end-diastolic and end-systolic volumes were inversely associated with TSH, and ejection fraction was nonlinearly associated with FT3, with higher ejection fractions near the limits of the reference range. Left ventricle (LV) posterior wall thickness was nonlinearly associated with FT4 in the adjusted model 1, with a greater thickness near the limits of the reference range. Regarding diastolic function, no significant associations were observed in adjusted models.

CONCLUSIONS

Thyroid function within the reference range was associated with heart rate, blood pressure, cardiac structure, and function. Increasing thyroid function (lower TSH, higher FT4, or higher FT3) was associated with a higher heart rate, a lower diastolic blood pressure, and larger LV volumes. LV wall thickness and ejection fraction had a U-shaped association with thyroid hormones.

Body volume is the major determinant of worsening renal function in acutely decompensated heart failure with reduced left ventricular ejection fraction

AIMS

Little is known about the relative importance of body volume and haemodynamic parameters in the development of worsening of renal function in acutely decompensated heart failure (ADHF). To study the relationship between haemodynamic parameters, body water content and worsening of renal function in patients with heart failure with reduced ejection fraction (HFrEF) hospitalised for ADHF.

METHODS AND RESULTS

This prospective observational study involved 51 consecutive patients with HFrEF (age: 73±14 years, male: 60%, left ventricular ejection fraction: 33.3%±9.9%) hospitalised for ADHF. Echocardiographic-determined haemodynamic parameters and body volume determined using a bioelectric impedance analyser were serially obtained. All patients received intravenous furosemide 160 mg/day for 3 days. There was a mean weight loss of 3.95±2.82 kg (p<0.01), and brain natriuretic peptide (BNP) reduced from 1380±901 pg/mL to 797±738 pg/mL (p<0.01). Nonetheless serum creatinine (SCr) increased from 134±46 μmol/L to 151±53 μmol/L (p<0.01), and 35% of patients developed worsening of renal function. The change in SCr was positively correlated with age (r=0.34, p=0.017); and negatively with the ratio of extracellular water to total body water, a parameter of body volume status (r=-0.58, p<0.001); E:E' ratio (r=-0.36, p=0.01); right ventricular systolic pressure (r=-0.40, p=0.009); and BNP (r=-0.40, p=0.004). Counterintuitively, no correlation was observed between SCr and cardiac output, or total peripheral vascular resistance. Regression analysis revealed that normal body volume and lower BNP independently predicted worsening of renal function.

CONCLUSIONS

Normal body volume and lower serum BNP on admission were associated with worsening of renal function in patients with HFrEF hospitalised for ADHF.

Evaluation of diastolic function in newly diagnosed hyperthyroid patients with preserved left ventricular systolic function

Background

Diastolic dysfunction has been reported as a cardiovascular effect of hyperthyroidism, and is also supposed to be a cause of heart failure manifestations in the patients with preserved ejection fraction (EF).

Methods

For evaluation of diastolic function in hyperthyroid patients and also diastolic function during performing exercise stress echocardiography, we conducted this study on 25 newly diagnosed hyperthyroid patients compared to 26 healthy subjects as control group. Diastolic function of the patients at rest was assessed using these parameters as follows: left atrium volume index, tricuspid regurgitation (TR) velocity, mitral inflow early diastolic flow (E wave), tissue Doppler of mitral annular velocity (e′), E/e′ ratio, and isovolumic relaxation time (IVRT); and during exercise stress echocardiography, we judged diastolic response by measuring E/e′ ratio and TR velocity at the peak of stress.

Results

The mean age of the patients was 39.64 ± 12.23 years old and 52% of them were female. History of exertional dyspnea was found in 64% of patients. All the patients had normal diastolic function at the time of resting and there was no significant difference in diastolic parameters between the two groups except for IVRT, which was lower in hyperthyroid patients. Interestingly, no patients developed diastolic dysfunction during exercise stress echocardiography.

Conclusion

Our finding did not show diastolic dysfunction in hyperthyroid patients neither at rest nor during exercise echocardiography and did not support the hypothesis that diastolic dysfunction can be a cause of exertional intolerance and dyspnea in the patients with preserved EF.

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.

Hyperthyroidism

Hyperthyroidism is a condition where the thyroid gland produces and secretes inappropriately high amounts of thyroid hormone which can lead to thyrotoxicosis. The prevalence of hyperthyroidism in the United States is approximately 1.2%. There are many different causes of hyperthyroidism, and the most common causes include Graves' disease (GD), toxic multinodular goiter and toxic adenoma. The diagnosis can be made based on clinical findings and confirmed with biochemical tests and imaging techniques including ultrasound and radioactive iodine uptake scans. This condition impacts many different systems of the body including the integument, musculoskeletal, immune, ophthalmic, reproductive, gastrointestinal and cardiovascular systems. It is important to recognize common cardiovascular manifestations such as hypertension and tachycardia and to treat these patients with beta blockers. Early treatment of cardiovascular manifestations along with treatment of the hyperthyroidism can prevent significant cardiovascular events. Management options for hyperthyroidism include anti-thyroid medications, radioactive iodine, and surgery. Anti-thyroid medications are often used temporarily to treat thyrotoxicosis in preparation for more definitive treatment with radioactive iodine or surgery, but in select cases, patients can remain on antithyroid medications long-term. Radioactive iodine is a successful treatment for hyperthyroidism but should not be used in GD with ophthalmic manifestations. Recent studies have shown an increased concern for the development of secondary cancers as a result of radioactive iodine treatment. In the small percentage of patients who are not successfully treated with radioactive iodine, they can undergo re-treatment or surgery. Surgery includes a total thyroidectomy for GD and toxic multinodular goiters and a thyroid lobectomy for toxic adenomas. Surgery should be considered for those who have a concurrent cancer, in pregnancy, for compressive symptoms and in GD with ophthalmic manifestations. Surgery is cost effective with a high-volume surgeon. Preoperatively, patients should be on anti-thyroid medications to establish a euthyroid state and on beta blockers for any cardiovascular manifestations. Thyroid storm is a rare but life-threatening condition that can occur with thyrotoxicosis that must be treated with a multidisciplinary approach and ultimately, definitive treatment of the hyperthyroidism.

Prevalence and Risk Factors of Left Ventricular Diastolic Dysfunction in Patients With Hyperthyroidism

BACKGROUND

Left ventricular (LV) diastolic dysfunction has been demonstrated to be an independent predictor of the future heart failure. Heart failure is one of the severe complications caused by overt hyperthyroidism. However, the effects of overt hyperthyroidism on diastolic dysfunction are conflicting, and little is known about the prevalence and risk factors of the diastolic dysfunction in patients with overt hyperthyroidism.

METHODS

A total of 388 patients with overt hyperthyroidism were included and compared with 388 age- and gender- matched euthyroid control subjects. LV diastolic function was evaluated by traditional and tissue-Doppler echocardiography. Routine clinical medical data and echocardiographic parameters were recorded for analysis.

RESULTS

The prevalence of LV diastolic dysfunction was 35.1% among hyperthyroid patients and significantly higher than control subjects whose prevalence was 25.5% (P = 0.003), and it increased with age and body mass index (BMI) in patients with overt hyperthyroidism. The possible risk factors for LV diastolic dysfunction, such as hypertension, diabetes, decreased estimated glomerular filtration rate (eGFR), and increased level of thyroid hormones weren't associated with LV diastolic dysfunction. However, overweight or obese were significantly associated with LV diastolic dysfunction (OR = 3.024, 95% CI = 1.517-6.027, P = 0.002) compared with normal BMI. When compared with age <40 years old group, 40-50 years old group, 50-60 years old group and age ≥60 years old group were significantly associated with LV diastolic dysfunction, with ORs of 2.976 (95% CI = 1.744-5.019), 12.424 (95% CI = 4.934-31.283), 24.966 (95% CI = 5.975-104.321), respectively.

CONCLUSION

LV diastolic dysfunction was very common, in particular, in older and overweight or obese patients with overt hyperthyroidism. Additionally, age and BMI were independent risk factors for LV diastolic dysfunction, while the level of thyroid hormones was not. Therefore, besides the LV systolic function, we also need focus on the diastolic function in patients with overt hyperthyroidism in clinical work, especially the older and overweight or obese patients.

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.

Cardiovascular Implications of Diabetes, Metabolic Syndrome, Thyroid Disease, and Cardio-Oncology in Women

Cardiovascular disease may be associated with several comorbidities, including diabetes mellitus, thyroid disorders, and the metabolic syndrome, which are predominantly observed in women and often starting at particular ages. In addition, common treatment options for carcinomas frequently seen in women may induce serious cardiotoxic effects. We review the scope of the problem, the pathophysiologic mechanisms involved, as well as the resulting abnormalities regarding cardiac structure and function as observed by using imaging techniques.

Hypertension in Thyroid Disorders

Arterial hypertension represents a major global health concern; more than one fourth of the population is affected by high blood pressure. Albeit the underlying cause of the disease remains unclear in the vast majority of the cases, ~10% are of secondary origin. Endocrine disorders are common illnesses and some of them may lead to elevated blood pressure, among which thyroid diseases are of high prevalence and often overlooked, especially in mild cases. Overt and subclinical hyper- and hypothyroidism can both lead to (mostly mild) hypertension; however, the underlying mechanisms are only partially understood. The results of clinical studies are often controversial. During the past decades, some genetic mutations in the hypothalamus-pituitary-thyroid axis with cardiovascular consequences were revealed. Atherosclerotic changes resulting from lipid abnormalities due to thyroid dysfunction also affect the vasculature and can cause elevated blood pressure. The review gives a synopsis of our knowledge how thyroid hormone metabolism and functional thyroid diseases affect the cardiovascular system, their negative impact and causative role in the development of hypertension.

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.

Recovery following Thyroxine Treatment Withdrawal, but Not Propylthiouracil, Averts In Vivo and Ex Vivo Thyroxine-Provoked Cardiac Complications in Adult FVB/N Mice

Persistent cardiovascular pathology has been described in hyperthyroid patients even with effective antithyroid treatment. Here, we studied the effect of a well-known antithyroid drug, propylthiouracil (PTU; 20 mg/kg/day), on thyroxine (T4; 500 µg/kg/day)-induced increase in blood pressure (BP), cardiac hypertrophy, and altered responses of the contractile myocardium both in vivo and ex vivo after 2 weeks of treatment. Furthermore, the potential recovery through 2 weeks of T4 treatment discontinuation was also investigated. PTU and T4 recovery partially reduced the T4-prompted increase in BP. Alternatively, PTU significantly improved the in vivo left ventricular (LV) function with no considerable effects on cardiac hypertrophy or ex vivo right ventricular (RV) contractile alterations subsequent to T4 treatment. Conversely, T4 recovery considerably enhanced the T4-provoked cardiac changes both in vivo and ex vivo. Altogether, our data is in agreement with the proposal that hyperthyroidism-induced cardiovascular pathology could persevere even with antithyroid treatments, such as PTU. However, this cannot be generalized and further investigation with different antithyroid treatments should be executed. Moreover, we reveal that recovery following experimental hyperthyroidism could potentially ameliorate cardiac function and decrease the risk for additional cardiac complications, yet, this appears to be model-dependent and should be cautiously construed.

Thyrotoxicosis presenting as exertional dyspnea and pulmonary hypertension: Case report and review of literature

Objectives:

In this case study, we describe a 35-year-old woman with pulmonary hypertension that was secondary to thyrotoxicosis who presented with exertional dyspnea. In the approach to exertional dyspnea, detailed physical examination and laboratory findings helped to get the diagnosis.

Methods:

Echocardiography showed right ventricular systolic pressure = 60 mmHg. A suppressed thyroid-stimulating hormone was seen in lab tests. The patient was treated with radioactive iodine.

Results:

Palpitations and shortness of breath improved, and both her thyroid-stimulating hormone and T4 levels decreased. Echocardiography and the pulmonary pressure were normal after treatment.

Conclusions:

Thyrotoxicosis is one of the etiologies of pulmonary hypertension, but the exact etiology and pathogenesis remain unknown. Some patients may have symptomatic pulmonary hypertension that can be resolved by hyperthyroidism treatment.

Relationship between the abnormal diastolic vortex structure and impaired left ventricle filling in patients with hyperthyroidism

Intraventricular hydrodynamics plays an important role in evaluating cardiac function. Relationship between diastolic vortex and left ventricular (LV) filling is still rarely elucidated. The aim of this study was to evaluate the evolution of vortex during diastole in hyperthyroidism (HT) and explore the alteration of hydromechanics characteristics with sensitive indexes.Forty-three patients diagnosed with HT were classified into 2 groups according to whether myocardial damage existed: simple hyperthyroid group (HT1, n = 21) and thyrotoxic cardiomyopathy (HT2, n = 22). Twenty-seven age- and gender-matched healthy volunteers were enrolled as the control group. Offline vector flow mapping (VFM model) was used to analyze the LV diastolic blood flow patterns and fluid dynamics. Hemodynamic parameters, vortex area (A), circulation (C), and intraventricular pressure gradient (ΔP), in different diastolic phases (early, mid, and late) were calculated and analyzed.HT2, with a lower E/A ratio and left ventricular ejection fraction (LVEF), had a larger left atrium diameter (LAD) compared with those of the control group and HT1 (P < .05). Compared with the control group, the vortex size and strength, intraventricular pressure gradient during early and mid-diastole were higher in HT1 and lower in HT2 (P < .05). And in late diastole, the vortex size and strength, intraventricular pressure gradient of HT2 became higher than those of the control group (P < .05). Good correlation could be found between CE and E/A (P < .05), CM and ΔPM (P < .01), CL and FT3 (P < .05).VFM is proven practical for detecting the relationship between the changes of left ventricular diastolic vortex and the abnormal left ventricular filling.

Hyperdynamic Right Heart Function in Graves' Hyperthyroidism Measured by Echocardiography Normalises on Restoration of Euthyroidism

BACKGROUND

Graves' hyperthyroidism commonly causes tachycardia and may result in pulmonary hypertension and high output cardiac failure. There is limited information regarding the effect of treatment on cardiac function measured using modern echocardiographic techniques.

METHODS

Eight individuals with Graves' hyperthyroidism, aged 22-64 years, underwent comprehensive transthoracic echocardiography at three time points: before treatment, two weeks after commencement of carbimazole, and at six months or more when euthyroid. Exercise capacity was assessed using the 6-minute-walk-distance (6MWT), and quality of life was assessed by Medical Outcome Study 36-item Short-Form Health Status Survey.

RESULTS

All individuals were rendered euthyroid by final assessment. At presentation, there was evidence of hyperdynamic right ventricular function as measured by peak systolic velocity of the free wall of the tricuspid annulus, tricuspid annular plane systolic excursion and right ventricular ejection fraction, which normalised after resolution of thyrotoxicosis. Baseline heart rate correlated significantly with severity of the thyrotoxicosis for either free T4 (r = 0.91, p=0.01) or free T3 (r=0.94, p=0.001). No individual had measurable pulmonary hypertension. Cardiac output was significantly lower in the euthyroid compared to the thyrotoxic state (p=0.03). A higher baseline TSH-receptor antibody titre corresponded to a greater improvement in exercise capacity (r=0.76, p<0.05) and physical quality of life (r=0.73, p<0.05) on resolution of the hyperthyroidism.

CONCLUSION

Graves' hyperthyroidism causes increased cardiac output and a hyperdynamic right ventricle which normalise on restoration of the euthyroid state.

Impact of Antithrombotic Therapy in Atrial Fibrillation on the Presentation of Coronary Artery Disease

Background

Little is known about whether atrial fibrillation is a presentation of coronary disease. There is a paucity of knowledge about their causal relationship and also the impact of different antithrombotic strategies on the subsequent presentation of symptomatic coronary disease.

Methods and Results

We studied 7,526 Chinese patients diagnosed with non-valvular atrial fibrillation and no documented history of coronary artery disease. The primary endpoint was the new occurrence of coronary artery disease—either stable coronary artery disease or acute coronary syndrome. After a mean follow-up of 3.2±3.5 years (24,071 patient-years), a primary endpoint occurred in 987 patients (13.1%). The overall annual incidence of coronary artery disease was 4.10%/year. No significant differences in age, sex, and mean CHA₂DS₂-VASc score were observed between patients with and without the primary endpoint. When stratified according to the antithrombotic strategies applied for stroke prevention, the annual incidence of coronary artery disease was 5.49%/year, 4.45%/year and 2.16%/year respectively in those prescribed no antithrombotic therapy, aspirin, and warfarin. Similar trends were observed in patients with acute coronary syndromes. Diabetes mellitus, smoking history and renal failure requiring dialysis were predictors for primary endpoint in all antithrombotic therapies.

Conclusion

In patients with non-valvular atrial fibrillation, there is a modest association with coronary artery disease. Patients prescribed warfarin had the lowest risk of new onset coronary artery disease.

Echocardiographic assessment of left ventricular function in thyrotoxicosis and implications for the therapeutics of thyrotoxic cardiac disease

INTRODUCTION

Thyrotoxicosis is an endocrine disorder with prominent cardiovascular manifestations. Thyroid hormone acts through genomic and non-genomic mechanisms to regulate cardiac function. Echocardiography is a useful, non-invasive, easily accessible, and affordable tool for studying the structural and physiological function of the heart.

AIM

We studied thyrotoxicosis patients in a Nigerian Teaching Hospital and employed trans-thoracic echocardiography to find out if there were abnormalities in the hearts of these patients.

METHODS

Fifty adult thyrotoxicosis patients diagnosed with clinical and thyroid function tests in the medical out-patient unit of the hospital were recruited and we performed transthoracic echocardiography with a Sonos 2000 HP machine.

RESULTS

We documented the presence of abnormalities in the following proportion of thyrotoxicosis patients: left ventricular enhanced systolic function in 30%, enhanced diastolic function in 34%, diastolic dysfunction in 34%, heart failure with preserved ejection fraction in10%, heart failure with reduced ejection fraction in 6%, and left ventricular hypertrophy in 34%.

CONCLUSION

Echocardiography was useful in the stratification of cardiac function abnormalities and is indispensable as a guide in the choice of therapeutic options in patients with thyrocardiac disease. The finding of left ventricular enhanced systolic and diastolic functions signify early echocardiographic detectable cardiac abnormalities in thyrotoxicosis, and the clinical management includes the use of anti-thyroid drugs and β-adrenoceptor blockade. Diastolic dysfunction in thyrotoxicosis patients asymptomatic for cardiac disease should be treated with anti-thyroid drugs, and β-adrenoceptor blockade. The judicious application of clinical therapeutics will guide the use of anti-thyroid drugs, diuretics, digoxin, angiotensin inhibitors, and β-adrenoceptor blockade in the successful management of thyrotoxicosis patients with heart failure and reduced, preserved, or increased ejection fraction: parameters which are derived from echocardiography.

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

Cardiovascular complications are important in hyperthyroidism because of their high frequency in clinical presentation and increased mortality and morbidity risk. The cause of hyperthyroidism, factors related to the patient, and the genetic basis for complications are associated with risk and the basic underlying mechanisms are important for treatment and management of the disease. Besides cellular effects, hyperthyroidism also causes hemodynamic changes, such as increased preload and contractility and decreased systemic vascular resistance causes increased cardiac output. Besides tachyarrythmias, impaired systolic ventricular dysfunction and diastolic dysfunction may cause thyrotoxic cardiomyopathy in a small percentage of the patients, as another high mortality complication. Although the medical literature has some conflicting data about benefits of treatment of subclinical hyperthyroidism, even high-normal thyroid function may cause cardiovascular problems and it should be treated. This review summarizes the cardiovascular consequences of hyperthyroidism with underlying mechanisms.

Determinants of thyrotoxic cardiomyopathy recovery

The purpose was to evaluate the effect of the disease duration prior to treatment, thyroid hormones level, or both on the reversibility of dilated cardiomyopathy. Between January 2006 and December 2010, a longitudinal study with a 6 months follow-up was carried on. One hundred and seventy patients with hyperthyroidism were referred to the cardiologist, and 127 had a 6 months followup after antithyroid treatment and were evaluated by echocardiography. Dilated cardiomyopathy reversibility criteria were established according to echocardiographic parameters. Complete reversibility existed when all parameters were met, partial reversibility when LVEF was ≥55% plus two or three other parameters, and no reversibility when LVEF was ≤55% regardless of other parameters. The results showed that echocardiography parameters related to the regression of myocardial mass were associated with a disease duration shorter than 10.38 months. This was the main predictive variable for reversal of dilated cardiomyopathy, followed by β-blocker treatment, and the last predictive variable was the serum level of free triiodothyronine. This study showed that the effect on the myocardium related to thyrotoxicosis was associated with the disease duration before treatment.

Morbidity before and after the diagnosis of hyperthyroidism: a nationwide register-based study

BACKGROUND

Hyperthyroidism has been linked with different morbidities, like atrial fibrillation, stroke and diabetes mellitus. However, our knowledge regarding the extent and temporal relation between hyperthyroidism and other diseases is fragmented. Here, we aimed at evaluating various morbidities before and after the diagnosis of hyperthyroidism.

METHODS

Observational cohort study. From nationwide Danish health registers 2631 hyperthyroid singletons and 375 twin pairs discordant for hyperthyroidism were identified and followed for an average of 6 years (range 0-13). Data on the occurrence of cardiovascular diseases, lung diseases, diabetes mellitus, rheumatic diseases and malignant diseases was obtained by person-to-person record linkage with the National Danish Patient Register and/or the Danish National Prescription Registry (lung diseases and diabetes mellitus). Logistic and Cox regression models were used to assess the risk of morbidity before and after the diagnosis of hyperthyroidism, respectively. All Cox regression analyses were adjusted for the degree of co-morbidity preceding the diagnosis of hyperthyroidism, using the Charlson score.

RESULTS

Hyperthyroid individuals had a significantly higher risk of being diagnosed with cardiovascular diseases (odds ratio (OR) 1.65; 95% confidence interval (CI): 1.45-1.87), lung diseases (OR 1.53; 95% CI: 1.29-1.60), and diabetes mellitus (OR 1.43, 95% CI: 1.20-1.72), but not with malignant diseases (OR 1.16, 95% CI: 0.99-1.36) prior to the diagnosis of hyperthyroidism. After the diagnosis of hyperthyroidism, subjects had a significantly higher risk of being diagnosed with cardiovascular diseases (hazard ratio (HR) 1.34; 95% CI: 1.15-1.56), lung diseases (HR 1.28; 95% CI: 1.10-1.49), and diabetes mellitus (HR 1.46; 95% CI: 1.16-1.84), but not with rheumatic diseases (HR 1.39, 95% CI: 0.92-2.09) or malignant diseases (HR 1.18, 95% CI 0.97-1.42).

CONCLUSIONS

We demonstrate a significantly increased burden of morbidity, both before and after the diagnosis of hyperthyroidism.

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.

Unilateral pitting edema of the leg as a manifestation of Graves' disease: a case report

Introduction

Graves’ hyperthyroidism has a number of well-recognized but relatively rare extrathyroid manifestations such as thyroid acropachy, pretibial myxedema, and congestive heart failure.

Case presentation

A 38-year-old Caucasian woman presented to the out-patient clinic with symptoms of hyperthyroidism lasting for approximately five months. Remarkably, she had developed pitting edema of her left leg four months before. She had gone through a conventional assessment, but the reason for the edema was not revealed. At presentation to the endocrinology clinic, the skin of both legs was of normal color and pitting edema on her left leg was of a diffuse nature and spread from her toes to two thirds of her leg. The skin surface of her left leg was smooth and had no elevations or discoloration, whereas her right leg appeared normal. Based on signs and symptoms of thyrotoxicosis and suppressed thyroid-stimulating hormone level (less than 0.001mIU/L, local reference of 0.4 to 4), treatment of 10mg of thiamazole three times a day was started. Additional blood tests revealed marked Graves’ hyperthyroidism with elevated free T4 and anti-thyroid receptor antibodies. Within a month, the free T4 level was normalized and the edema was completely cleared and never reappeared during the treatment course of 12 months.

Conclusions

To the best of our knowledge, this is the first description of unilateral treatment-responsive leg edema as a manifestation of Graves’ hyperthyroidism. However, the pathophysiological mechanism underlying this case of edema remains unclear.

Coronary vasoreactivity in subjects with thyroid autoimmunity and subclinical hypothyroidism before and after supplementation with thyroxine

BACKGROUND

The association of subclinical hypothyroidism (SCH) with increased risk for cardiovascular disease is still controversial. This study aimed to examine coronary vascular reactivity by positron emission tomography (PET) in asymptomatic patients with SCH before and after levothyroxine (LT4) supplementation.

METHODS

Ten patients (7 women and 3 men; mean age 43±15 years) with untreated autoimmune SCH, defined by elevated levels of thyroid-stimulating hormone (mean TSH: 16.9±11.3 μU/mL), normal levels of free thyroxine (0.9±0.1 μg/mL), free triiodothyronine (3.2±0.4 pg/mL), and positive thyroid peroxidase antibodies were studied. Eight euthyroid subjects with similar low-risk cardiovascular risk profile served as controls. Myocardial blood flow (MBF) and coronary flow reserve (CFR) were quantitatively assessed with rest/stress N-13 ammonia PET at baseline and after 6 months of LT4 replacement therapy (given only to patients).

RESULTS

At baseline, stress MBF and CFR corrected (c) for rate pressure product (RPP) and myocardial vascular resistance (MVR) during stress were significantly reduced in SCH compared with controls (stress MBF: 2.87±0.93 vs. 4.79±1.16 mL/g/min, p=0.003; CFR: 2.6±0.73 vs. 4.66±1.38, p=0.004; MVR: 40.14±18.76 vs. 20.47±6.24 mmHg/mL/min, p=0.02). Supplementation therapy with LT4 normalized TSH in all subjects and was associated with an increase in CFR (2.6±0.73 vs. 3.81±1.19, p=0.003) and with a tendency toward a decrease in MVR. Differences in CFR between SCH and controls were also seen after correction of resting MBF for RPP.

CONCLUSIONS

In asymptomatic subjects with SCH due to thyroid autoimmunity, coronary microvascular function is impaired and improves after supplementation with LT4. This may partially explain the increased cardiovascular risk attributed to SCH.

A review of literature on the adverse effects of hyperthyroidism on the heart functional behavior

Thyroid hormones play an important role on the physiological chemistry of heart and vascular systems in healthy subjects. Any thyroid disorders accompanied with alteration of effective concentration of thyroid hormones cause heart dysfunctions. Thyrotoxicosis is a term given for the clinical manifestation of hyperthyroidism which can invoke heart and vascular abnormalities through the mechanism at heart muscle cells nuclear level. Thyrotoxicosis can play positive roles for heart disorders including atrial fibrillation, left ventricular hypertrophy and right ventricular systolic dysfunction, which are considered as major risk factors for heart abnormalities. Miscalculation of heart dysfunctions related thyrotoxicosis in cardiovascular patients might be avoided through careful laboratory measurements of T4 and T3 to exclude any possible thyroid hormone-related heart diseases.