scholarly journals Abnormal Cardiac Repolarization in Thyroid Diseases: Results of an Observational Study

2021 ◽  
Vol 8 ◽  
Author(s):  
Assem Aweimer ◽  
Fabian Schiedat ◽  
Dominik Schöne ◽  
Gabi Landgrafe-Mende ◽  
Harilaos Bogossian ◽  
...  

Background: The relationship between thyroid function and cardiac disease is complex. Both hypothyroidism and thyrotoxicosis can predispose to ventricular arrhythmia and other major adverse cardiovascular events (MACE), so that a U-shaped relationship between thyroid signaling and the incidence of MACE has been postulated. Moreover, recently published data suggest an association between thyroid hormone concentration and the risk of sudden cardiac death (SCD) even in euthyroid populations with high-normal FT4 levels. In this study, we investigated markers of repolarization in ECGs, as predictors of cardiovascular events, in patients with a spectrum of subclinical and overt thyroid dysfunction.Methods: Resting ECGs of 100 subjects, 90 patients (LV-EF > 45%) with thyroid disease (60 overt hyperthyroid, 11 overt hypothyroid and 19 L-T4-treated and biochemically euthyroid patients after thyroidectomy or with autoimmune thyroiditis) and 10 healthy volunteers were analyzed for Tp-e interval. The Tp-e interval was measured manually and was correlated to serum concentrations of thyroid stimulating hormone (TSH), free triiodothyronine (FT3) and thyroxine (FT4).Results: The Tp-e interval significantly correlated to log-transformed concentrations of TSH (Spearman's rho = 0.30, p < 0.01), FT4 (rho = −0.26, p < 0.05), and FT3 (rho = −0.23, p < 0.05) as well as log-transformed thyroid's secretory capacity (SPINA-GT, rho = −0.33, p < 0.01). Spearman's rho of correlations of JT interval to log-transformed TSH, FT4, FT3, and SPINA-GT were 0.51 (p < 1e−7), −0.45 (p < 1e−5), −0.55 (p < 1e−8), and −0.43 (p < 1e−4), respectively. In minimal multivariable regression models, markers of thyroid homeostasis correlated to heart rate, QT, Tp-e, and JT intervals. Group-wise evaluation in hypothyroid, euthyroid and hyperthyroid subjects revealed similar correlations in all three groups.Conclusion: We observed significant inverse correlations of Tp-e and JT intervals with FT4 and FT3 over the whole spectrum of thyroid function. Our data suggest a possible mechanism of SCD in hypothyroid state by prolongation of repolarization. We do not observe a U-shaped relationship, so that the mechanism of SCD in patients with high FT4 or hyperthyroidism seems not to be driven by abnormalities in repolarization.

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Jianqing She ◽  
Jiahao Feng ◽  
Yangyang Deng ◽  
Lizhe Sun ◽  
Yue Wu ◽  
...  

Objective. The pathophysiologic mechanism of how thyroid function is related to the development and prognosis of acute myocardial infarction (AMI) remains under explored, and there has been a lack of clinical investigations. In this study, we investigate the relationship between triiodothyronine (T3) level and cardiac ejection fraction (EF) as well as probrain natriuretic peptide (NT-proBNP) on admission and subsequent prognosis in AMI patients. Methods. We measured admission thyroid function, NT-proBNP, and EF by echocardiography in 345 patients diagnosed with AMI. Simple and multiregression analyses were performed to investigate the correlation between T3 level and EF as well as NT-proBNP. Major adverse cardiovascular events (MACE), including new-onset myocardial infarction, acute heart failure, and cardiac death, were documented during the follow-up. 248 participants were separated into three groups based on T3 and free triiodothyronine (FT3) levels for survival analysis during a 2-year follow-up. Results. 345 patients diagnosed with AMI were included in the initial observational analysis. 248 AMI patients were included in the follow-up survival analysis. The T3 levels were found to be significantly positively correlated with EF (R square=0.042, P<0.001) and negatively correlated with admission NT-proBNP levels (R square=0.059, P<0.001), which is the same with the correlation between FT3 and EF (R square=0.053, P<0.001) and admission NT-proBNP levels (R square=0.108, P<0.001). Kaplan-Meier survival analysis revealed no significant difference with regard to different T3 or FT3 levels at the end of follow-up. Conclusions. T3 and FT3 levels are moderately positively correlated with cardiac function on admission in AMI patients but did not predict a long-time survival rate. Further studies are needed to explain whether longer-term follow-up would further identify the prognosis effect of T3 on MACE and all-cause mortality.


2018 ◽  
Vol 20 (1) ◽  
pp. 37
Author(s):  
Sharmin Quddus ◽  
Fatima Begum ◽  
Nasreen Sultana ◽  
Rahima Perveen ◽  
Tapati Mandal ◽  
...  

<p><strong>Objective:</strong> The modified fixed doses of radioactive iodine (RAI) in different types of hyperthyroidism had been practiced at National Institute of Nuclear Medicine &amp; Allied Science (NINMAS) according to Society of Nuclear Medicine Bangladesh (SNMB) protocol since 2002 which was upgraded in 2015. The objective of the study was to observe the treatment outcome in modified fixed dose on previous protocol. Patients and Methods: In the present study the outcome of radioiodine therapy of hyperthyroid patients was retrospectively evaluated in 1349 consecutive primary hyperthyroid patients treated from January 2010 to December 2014 at NINMAS. Diagnosis of hyperthyroidism was done by thyroid function test; thyroid stimulating hormone (TSH), free triiodothyronine (FT3)   &amp; free thyroxine (FT4), 99m Technetium scan, thyroid radioiodine uptake and ultrasound imaging of thyroid gland. All patients received a fixed dose (8-29 m Ci) of radioactive iodine (RAI) depending on types of hyperthyroidism, visual assessment of gland size and severity of disease at diagnosis. They were followed up at 2 months of therapy, then every three months intervals for first year and thereafter 6 monthly up to 5 years or as needed during fluctuation of thyroid function.</p><p><strong>Results:</strong> Among the study population, 832 patients had diffuse toxic goiter (Graves’ disease), 369 patients were diagnosed as toxic multinodular goiter and 148 patients with single toxic nodule. At one year follow-up, permanent hypothyroidism occurred in 61.62% of patients and the cumulative incidence of hypothyroidism progressively increased up to 79.25% after 5 years. Cure or success of RAI therapy was considered as attainment of euthyroid state or hypothyroid state. About 11.26 % patients received more than single dose.</p><p><strong>Conclusion:</strong> Fixed dose RAI therapy is very much cost effective mode of treatment for primary hyperthyroidism with ~89% success by giving single dose.</p><p>Bangladesh J. Nuclear Med. 20(1): 37-40, January 2017</p>


2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Yonghong Sheng ◽  
Dongping Huang ◽  
Shun Liu ◽  
Xuefeng Guo ◽  
Jiehua Chen ◽  
...  

Ethnic differences in the level of thyroid hormones exist among individuals. The American Thyroid Association (ATA) recommends that an institution or region should establish a specific thyroid hormone reference value for each stage of pregnancy. To date, a limited number of studies have reported the level of thyroid hormones in Chinese minorities, and the exact relationship between BMI and thyroid function in pregnant women is ill. This study was performed to establish trimester-specific reference ranges of thyroid hormones in Zhuang ethnic pregnant women and explore the role of body mass index (BMI) on thyroid function. A total of 3324 Zhuang ethnic health pregnant women were recruited in this Zhuang population-based retrospective cross-sectional study. The values of thyroid stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were determined by automatic chemiluminescence immunoassay analyzer. Multivariate linear regression and binary logistic regression were constructed to evaluate the influence of BMI on the thyroid function. The established reference intervals for the serum thyroid hormones in three trimesters were as follows: TSH, 0.02–3.28, 0.03–3.22, and 0.08-3.71 mIU/L; FT4, 10.57–19.76, 10.05–19.23, and 8.96–17.75 pmol/L; FT3, 3.51–5.64, 3.42–5.42, and 2.93–5.03 pmol/L. These values were markedly lower than those provided by the manufacturers for nonpregnant adults which can potentially result in 6.10% to 19.73% misclassification in Zhuang pregnant women. Moreover, BMI was positively correlated with isolated hypothyroxinemia (OR=1.081, 95% CI=1.007–1.161), while the correlation between the BMI and subclinical hypothyroidism was not statistically significant (OR=0.991, 95% CI=0.917–1.072). This is the first study focusing on the reference ranges of thyroid hormones in Guangxi Zhuang ethnic pregnant women, which will improve the care of them in the diagnosis and treatment. We also found that high BMI was positively associated with the risk of isolated hypothyroxinemia.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yingying Wang ◽  
Dandan He ◽  
Chaowei Fu ◽  
Xiaolian Dong ◽  
Feng Jiang ◽  
...  

BackgroundThe onset of puberty is influenced by thyroid function, and thyroid hormones (THs) fluctuate substantially during the period of pubertal development. However, it needs to be further clarified how THs change at specific puberty stages and how it influences pubertal development in girls. So far, longitudinal data from China are scarce.MethodsA cohort study was conducted among girls during puberty in iodine-sufficient regions of East China between 2017 to 2019. Serum thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were determined for each participant. Thyroid homeostasis structure parameters (THSPs), including the ratio of FT4 to FT3 (FT4/FT3), Jostel’s TSH index (TSHI), and thyroid feedback quantile-based index (TFQI), were calculated. Puberty category scores (PCS), calculated based on the Puberty Development Scale (PDS), was used to assess the stage of puberty. Girls were grouped into three categories according to PCS changes (△PCS) and six categories according puberty stage (BPFP: pre-pubertal at both baseline and follow-up; BPFL: pre-pubertal at baseline and late-pubertal at follow-up, respectively; BPFT: pre-pubertal at baseline and post-pubertal at follow-up, respectively; BLFL: late-pubertal at both baseline and follow-up; BLFT: late-pubertal at baseline and post-pubertal at follow-up, respectively; BTFT: post-pubertal at both baseline and follow-up). Multiple linear regression analyses were used to evaluate the associations of THs changes with pubertal progress.ResultsThe levels of serum TSH and FT3 decreased while serum FT4 increased during the study period (P&lt;0.001). In multiple linear regression analyses, after adjustment for covariables, FT3 decreased by an additional 0.24 pmol/L (95% CI: -0.47 to -0.01) in the higher △PCS group than the lower △PCS group. Compared with the BLFL group, the BPFT group showed an additional decline in FT3 (β= -0.39 pmol/L, 95%CI: -0.73 to -0.04), the BTFT group showed a lower decline in TSH (β=0.50 mU/L, 95% CI: 0.21 to 0.80) and a lower decline in TSHI (β=0.24, 95%CI: 0.06 to 0.41), respectively. There was no association of △FT4 or △TFQI with △PCS or the puberty pattern.ConclusionsSerum TSH and FT3 decreased while serum FT4 increased among girls during puberty. Both the initial stage and the velocity of pubertal development were related to thyroid hormone fluctuations.


2021 ◽  
Vol 10 (10) ◽  
pp. 1326-1336
Author(s):  
Nannan Bian ◽  
Xiaomeng Sun ◽  
Biao Zhou ◽  
Lin Zhang ◽  
Qiu Wang ◽  
...  

Objective Bariatric surgery has become the most effective treatment for morbid obesity. Increasing evidence showed that bariatric surgery can alleviate insulin resistance and influence thyroid function. This study aimed to investigate the relationship between changes in thyroid function and adipose tissue insulin resistance (adipo-IR) after bariatric surgery. Methods A total of 287 non-diabetic participants with regular thyroid function were recruited and divided into the lean, overweight and obese groups. Among them, 50 morbidly obese patients submitted to bariatric surgery. Results The obese group had a higher level of adipo-IR, thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), FT3/free thyroxine (FT4) and metabolism disorders than the lean and overweight groups. BMI was correlated with TSH, FT3, FT3/FT4 and adipo-IR (r = 0.309, 0.315, 0.322 and 0.651, respectively, all P < 0.001). Adipo-IR was significantly correlated with TSH (r = 0.402, P < 0.001), FT3 (r = 0.309, P < 0.001), and FT3/FT4 (r = 0.228, P < 0.05). Bariatric surgery resulted in a sharp decline in BMI, adipo-IR, TSH, FT3 and FT3/FT4 levels, meanwhile, metabolic disorders improved. The decrease in BMI after bariatric surgery was significantly correlated with reductions in adipo-IR (r = 0.577, P < 0.001) and TSH (r = 0.401, P = 0.005). Interestingly, the fasting blood glucose, fasting insulin, adipo-IR and TSH in the higher TSH group decreased more remarkably than in the lower TSH group. Conclusion Obese individuals with higher TSH levels had an obvious metabolic improvement after bariatric surgery.


2015 ◽  
Vol 8 ◽  
pp. CMED.S24111 ◽  
Author(s):  
Juha Saltevo ◽  
Hannu Kautiainen ◽  
Pekka Mäntyselkä ◽  
Antti Jula ◽  
Sirkka Keinänen-Kiukaanniemi ◽  
...  

The association between thyroid function and depression is controversial. Both conditions express many similar symptoms, but the studies done give conflicting results. This study draws on a random, population-based sample of 4500 subjects aged 45–75 years old from Finland. The basic clinical study was done in 2007 for 1396 men and 1500 women (64% participation rate). Thyroid stimulating hormone (TSH), free thyroxine (F-T4), and free triiodothyronine (F-T3) were measured in 2013 from frozen samples. The 21-item Beck Depression Inventory (BDI-21) was applied to assess depressive symptoms (score ≥10 points). The prevalence of depressive symptoms was 17.5% in women and 12.5% in men. In women, the mean levels of TSH, F-T4, and F-T3 without depressive symptoms vs. with the presence of depressive symptoms were 1.92/1.97 mU/L, 13.1/13.1 pmol/L, and 3.91/3.87 pmol/L (NS), respectively. In men, the levels were 1.87/1.94 mU/L, 13.5/13.7 pmol/L, and 4.18/4.12 pmol/L (NS), respectively. In multiple regression analysis, TSH had no relationship to BDI-21 total score. We found no association between depressive symptoms and thyroid values.


Author(s):  
Jayne A. Franklyn

Subclinical hypothyroidism is defined biochemically as the association of a raised serum thyroid-stimulating hormone (TSH) concentration with normal circulating concentrations of free thyroxine (T4) and free triiodothyronine (T3). The term subclinical hypothyroidism implies that patients should be asymptomatic, although symptoms are difficult to assess, especially in patients in whom thyroid function tests have been checked because of nonspecific complaints such as tiredness. An expert panel has recently classified individuals with subclinical hypothyroidism into two groups (1): (1) those with mildly elevated serum TSH (typically TSH in the range 4.5–10.0 mU/l) and (2) those with more marked TSH elevation (serum TSH >10.0 mU/l).


2019 ◽  
Vol 32 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Lorenzo Iughetti ◽  
Giulia Vivi ◽  
Antonio Balsamo ◽  
Andrea Corrias ◽  
Antonino Crinò ◽  
...  

AbstractBackgroundPrader-Willi syndrome (PWS) is a genetic disorder due to loss of expression of paternally transcribed genes of the imprinted region of chromosome 15q11-13. PWS is characterized by peculiar signs and symptoms and many endocrine abnormalities have been described (growth hormone deficiency, hypogonadotropic hypogonadism). The abnormalities of thyroid function are discussed in literature and published data are discordant. The aim of our study was to report the thyroid function in patients with PWS to identify the prevalence of thyroid dysfunction.MethodsThyroid function tests were carried out in 339 patients with PWS, aged from 0.2 to 50 years. A database was created to collect personal data, anthropometric data, thyroid function data and possible replacement therapy with L-thyroxine. Subjects were classified according to thyroid function as: euthyroidism (EuT), congenital hypothyroidism (C-HT), hypothyroidism (HT – high thyroid-stimulating hormone [TSH] and low free thyroxine [fT4]), central hypothyroidism (CE-H – low/normal TSH and low fT4), subclinical hypothyroidism (SH – high TSH and normal fT4), and hyperthyroidism (HyperT – low TSH and high fT4).ResultsTwo hundred and forty-three out of 339 PWS patients were younger than 18 years (71.7%). The prevalence of thyroid dysfunction was 13.6%. Specifically, C-HT was found in four children (1.18%), HT in six patients (1.77%), CE-H in 23 patients (6.78%), SH in 13 patients (3.83%), and HyperT in none. All other subjects were in EuT (86.4%).ConclusionsHypothyroidism is a frequent feature in subjects with PWS. Thyroid function should be regularly investigated in all PWS patients both at the diagnosis and annually during follow-up.


Perfusion ◽  
2001 ◽  
Vol 16 (6) ◽  
pp. 469-475 ◽  
Author(s):  
Dan L Stewart ◽  
Noah Ssemakula ◽  
Duncan R MacMillan ◽  
L Jane Goldsmith ◽  
Larry N Cook

The object was to study thyroid function in neonates with severe respiratory failure on extracorporeal membrane oxygenation (ECMO) and determine whether abnormal thyroid function correlates with prognosis. Total and free thyroxine (T4, FT4), total and free triiodothyronine (T3, FT3), reverse triiodothyronine (rT3), thyroid-stimulating hormone, and thyroxine binding globulin were measured in 14 newborn infants with severe respiratory failure (age 1-30 days) from samples collected before anesthesia for cannula placement, at 30, 60, and 360 min after initiation of ECMO, and on days 2, 4, 6, and 8. The patients were divided into survivors and non-survivors for statistical analyses. No differences were noted between survivors and non-survivors in the pre-ECMO mean serum concentrations of the thyroid function tests analyzed. In nine survivors, mean serum T4, FT4, T3, FT3, and rT3 all declined significantly within 30-60 min after initiation of ECMO, compared to baseline values. The values for all mean serum concentrations recovered completely and exceeded baseline between days 2 and 8. In five non-survivors, the decline of all mean serum values was not statistically significant and recovery to baseline was not achieved. The ratios of mean serum concentration of rT3/FT3were significantly different between survivors and non-survivors across all times during the ECMO course ( p λ 0.0005). These findings indicate that abnormalities in thyroid function occur in neonates with severe respiratory failure on ECMO and that the rT3/FT3 ratio correlates with prognosis over the ECMO course. Survival was associated with a significant reduction of serum thyroid hormone concentrations followed by recovery. We speculate that, in neonates with respiratory failure on ECMO, adaptive mechanisms which enhance survival include the capacity to down-regulate the pituitary-thyroid axis.


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