ABSTRACT Differentiated thyroid carcinoma (DTC) accounts for most cases of thyroid cancer, and the heterogeneity of DTC requires that management decisions be taken by a multidisciplinary team involving endocrinologists, head and neck surgeons, nuclear medicine physicians, pathologists, radiologists, radiation oncologists, and medical oncologists. It is important for nonspecialists to recognize and refer patients with DTC who will benefit from a specialized approach. Recent advances in knowledge and changes in management of DTC call for the need to raise awareness on the part of these nonspecialist physicians, including general endocrinologists and medical oncologists at large. We provide an overview of diagnostic and therapeutic principles in DTC, especially those that bear direct implication on day-to-day management of these patients by generalists. Patients with DTC may be broadly categorized as having localized, locally persistent/recurrent, or metastatic disease. Current recommendations for DTC include a three-tiered system that classifies patients with localized disease into low, intermediate, or high risk of persistent or recurrent disease. Risk stratification should be performed at baseline and repeated on an ongoing basis, depending on clinical evolution. One of the overarching goals in the management of DTC is the need to personalize treatment by tailoring its modality and intensity according to ongoing prognostic stratification, evolving knowledge about the disease, and patient characteristics and preference. In metastatic disease that is refractory to radioactive iodine, thyroid tumors are being reclassified into molecular subtypes that better reflect their biological properties and for which molecular alterations can be targeted with specific agents. (DTC cancer surgeons physicians pathologists radiologists approach large daytoday day generalists persistentrecurrent persistent/recurrent threetiered three tiered low intermediate basis evolution preference iodine agents

ABSTRACT Objective The aim of this observational, cross-sectional study was to investigate physicians’ preferences for radioiodine (RAI) treatment in patients with differentiated thyroid cancer (DTC) in Brazil and the factors influencing RAI indications. Materials and methods A survey was distributed to physicians potentially involved in DTC care in Brazil to understand the factors influencing RAI indications. The survey collected information on the profiles of the physicians, along with the characteristics of their workplaces and their preferences regarding RAI indications in three hypothetical clinical cases. Cases 1, 2, and 3 described the cases of patients with DTC and variations to the case that included different scenarios to assess how the respondents would change their RAI recommendations. The analysis included the RAI indications across different medical specialties. Results A total of 175 physicians answered the survey. There was considerable variability in RAI recommendations in all three cases. The training background influenced the respondents' preferences for RAI indications and their approaches to preparing patients for RAI treatment. Conclusion The findings of this study reaffirm the need for a Brazilian consensus among physicians across multiple specialties to help guide health care professionals treating patients with DTC in Brazil. observational crosssectional cross sectional (RAI (DTC 1 2 17

ABSTRACT Objectives: To assess the molecular profile of follicular cell-derived thyroid carcinomas (FCDTCs) and correlate the identified mutations with the clinical and pathological features of the affected patients. Materials and methods: Cross-sectional study of tumor samples from 100 adult patients diagnosed with FCDTC between 2010 and 2019. The patients’ clinical and pathological data were collected. Genomic DNA was extracted from formalin-fixed, paraffin-embedded (FFPE) tumors using the ReliaPrep FFPE gDNA Miniprep System. Genotyping of target genomic regions (KRAS, NRAS, BRAF, EGFR, and PIK3CA) was performed using the AmpliSeq panel, while sequencing was performed on the iSeq 100 platform. Results: The patients’ mean age was 39 years. In all, 82% of the tumors were classic papillary thyroid carcinomas. Overall, 54 (54%) tumor samples yielded satisfactory results on next-generation sequencing (NGS), of which 31 harbored mutations. BRAF gene mutations were the most frequent, with the BRAFV600E mutation present in 10 tumors. Seven tumors had BRAFNON-V600E mutations not previously described in FCDTCs (G464E, G464R, G466E, S467L, G469E, G596D, and the T599Ifs*10 deletion) but described in other types of cancer (i.e., skin/melanoma, lung, colorectal, and others). One tumor had a previously reported BRAFA598V mutation. EGFR gene mutations were found in 16 (29%) and KRAS or NRAS alterations in 8 (14%) of the 54 tumors analyzed. Conclusion: We described herein seven non-hotspot/novel variants in the BRAF gene, highlighting their potential role in expanding our understanding of FCDTC genetics. Objectives cellderived cell derived (FCDTCs methods Crosssectional Cross sectional 201 2019 collected formalinfixed, formalinfixed formalin fixed, fixed formalin-fixed paraffinembedded paraffin embedded (FFPE System KRAS, (KRAS PIK3CA PIKCA PIK CA panel platform Results 3 years all 82 Overall 5 54% (54% nextgeneration next generation NGS, NGS , (NGS) frequent BRAFVE BRAFV E 1 BRAFNONV600E BRAFNONVE BRAFNON V600E V G464E, G464E GE G (G464E G464R GR R G466E S467L SL S L G469E G596D GD D T599Ifs10 TIfs T599Ifs T Ifs T599Ifs*1 deletion i.e., ie i e (i.e. skinmelanoma skin melanoma skin/melanoma lung colorectal others. others . others) BRAFAV BRAFA 29% 29 (29% 14% 14 (14% analyzed Conclusion nonhotspot/novel nonhotspotnovel non hotspot/novel hotspot novel genetics 20 (54 (NGS BRAFNONV VE T599Ifs1 T599Ifs* i.e. (i.e 2 (29 (14 nonhotspot hotspotnovel (5 i.e (2 (1 (

ABSTRACT Objective: The objective of the study was to determine how physicians in Brazil manage Graves’ disease in different scenarios including extrathyroidal manifestations. Materials and methods: This study was conducted via a digital survey. The respondents (n = 573) answered multiple-choice questions based on a clinical case and variations of the case regarding laboratory and imaging evaluation, treatment choice, and follow-up. Results: The preferred initial treatment chosen by 95% of the respondents was ATD with a preferred treatment duration of 18-24 months. For 5% of the respondents, RAI was the initial treatment of choice. None of the respondents chose thyroidectomy. When presented with a patient with a desire for pregnancy in the near future, most respondents (69%) opted for ATD as the initial treatment. For a patient with signs of mild to moderate Graves’ orbitopathy, ATD remained the initial therapy for 93.9% of the respondents. For patients initially treated with ATD with disease recurrence after ATD interruption, most respondents (60%) chose definitive treatment with RAI. A similar survey published in 2011 by Burch and cols. had results comparable to those of the present survey but with a higher proportion of respondents choosing RAI (45% in the 2011 survey versus 5% in the present survey). Conclusion: Brazilian endocrinologists choose ATD as the initial management of Graves’ disease, and most choose RAI as a definitive treatment for a patient with relapse after ATD therapy. Objective Graves manifestations methods n 573 multiplechoice multiple choice evaluation followup. followup follow up. up follow-up Results 95 1824 18 24 18-2 months 5 thyroidectomy future 69% 69 (69% orbitopathy 939 93 9 93.9 interruption 60% 60 (60% 201 cols 45% 45 (45 . survey) Conclusion 57 182 1 2 18- 6 (69 93. (60 20 4 (4 (6 (

ABSTRACT Primary hypothyroidism is a common disorder in clinical practice. The management of most cases of hypothyroidism is usually straightforward, but the best approach in some special situations may raise questions among physicians. This position statement was prepared by experts from the Brazilian Society of Endocrinology and Metabolism to guide the management of three special situations, namely, hypothyroidism in the elderly, subclinical hypothyroidism in patients with heart disease, and difficult-to-control hypothyroidism. The authors prepared the present statement after conducting a search on the databases MEDLINE/PubMed, LILACS, and SciELO and selecting articles with the best evidence quality addressing the selected situations. The statement presents information about the current approach to patients in these special situations.

Abstract Objectives: This study aims to investigate if a sampling method using virtual networks is feasible to survey AS adoption among this “hard-to-reach” population of Brazilian doctors. Methods: An online piloted 11-point structured survey questionnaire (designed using Googleforms®) probed the actual treatment patterns for adult patients with PTMCs, including treatment decision-making nonoperative options, was undertaken between 10 November and 30 November 2020. Participants were reached by the mobile phone Application (APP) and a snowball sampling strategy was used to recruit a total of 4783 members (maximum number of potential reach), which is the total of doctors of the all 21 social media WhatsApp® groups. Results: From a total of 4783 members (maximum number of potential reach), there were 657 (13.7%) doctors (actual reach) who clicked the web link of the questionnaire, out of whom 512 (10.7%) fully completed the online survey. Among the survey respondents, 361 were endocrinologists (70.5%) and 151 were surgeons (29.5%). Overall, for low-risk PTMCs in an elderly patient, 118 responders (23%) recommend AS, while 390 (76%) recommend immediate surgery as the management, including lobectomy (18.5%) and Total Thyroidectomy (58.2%). The present responders tended to recommend surgery for PTMCs that were located adjacent to the dorsal surface of the thyroid, were multiple, or raised the size during the follow-up. Conclusion: Using snowball sampling strategy as an innovative route to conduct surveys was feasible and applicable but the rate of response was still very low. Our data also suggests the need to investigate if AS is embraced by Brazilian doctors. Objectives hardtoreach hard reach “hard-to-reach Methods 11point point 11 designed Googleforms® Googleforms decisionmaking decision making options 1 3 2020 APP (APP 478 maximum reach, , 2 WhatsApp groups Results 65 13.7% 137 13 7 (13.7% 51 10.7% 107 (10.7% respondents 36 70.5% 705 70 5 (70.5% 15 29.5%. 295 29.5% . 29 (29.5%) Overall lowrisk low risk patient 23% 23 (23% 39 76% 76 (76% management 18.5% 185 18 (18.5% 58.2%. 582 58.2% 58 (58.2%) thyroid multiple followup. followup follow up. up follow-up Conclusion 202 47 6 13.7 (13.7 10.7 (10.7 70.5 (70.5 29.5 (29.5% (23 (76 18.5 (18.5 58.2 (58.2% 20 4 13. (13. 10. (10. 70. (70. 29. (29.5 (2 (7 18. (18. 58. (58.2 (13 (10 (70 (29. ( (18 (58. (1 (29 (58 (5

ABSTRACT Objectives: This observational study analyzed telomerase reverse transcriptase (pTERT) mutations in 45 fine-needle aspiration (FNA) specimens obtained from thyroid nodules followed by postoperatively confirmation of papillary thyroid cancer (PTC) diagnosis, examining their relationship with clinicopathologic aspects and the BRAFV600E mutation. Subjects and methods: Clinical information was collected from patients who presented to Ribeirao Preto University Hospital for surgical consultation regarding a thyroid nodule and who underwent molecular testing between January 2010 to October 2012. Tests included a DNA-based somatic detection of BRAFV600E and pTERT mutations. Results: We found coexistence of pTERTC228T and BRAFV600E mutations in 8.9% (4/45) of thyroid nodules. All nodules positive for pTERT mutations were BRAFV600E positives. There was a significant association between pTERTC228T/BRAFV600E with older age and advanced stage compared with the group negative for either mutation. Conclusions: This series provides evidence that FNA is a reliable method for preoperative diagnosis of high-risk thyroid nodules. pTERTC228T/BRAFV600E mutations could be a marker of poor prognosis. Its use as a personalized molecular medicine tool to individualize treatment decisions and follow-up design needs to be further studied.

ABSTRACT Objectives: We aimed to investigate the prevalence of the BRAF (V600E) mutation in consecutive cases of papillary thyroid carcinoma (PTC) in patients diagnosed and treated at the Hospital Sao Rafael (Salvador, BA, Brazil) and evaluate its association with clinical and pathological characteristics of PTC. Subjects and methods: We retrospectively enrolled in the study a total of 43 consecutive PTC patients who underwent total thyroidectomy. We performed DNA extraction from formalin-fixed paraffin-embedded (FFPE) tumour tissue samples. Polymerase chain reaction (PCR) and direct sequencing were used to determine BRAF (V600E) mutation status. Univariate and multivariate logistic regression analyses were employed to identify independent associations. Results: The prevalence of BRAF (V600E) mutation was 65.1% (28/43). A high frequency of older patients (p value: 0.004) was observed among the BRAF-mutated PTC group and, in contrast, a low frequency of concurrent Hashimoto's thyroiditis (HT) (p value: 0.011) was noted. Multivariate analysis confirmed that older age (OR: 1.15; 95% CI: 1.00 – 1.33; p value: 0.047) and HT (OR: 0.05; 95% CI: 0.006-0.40; p value: 0.005) were independent factors associated with BRAF (V600E) mutation. Conclusion: We found a high prevalence of BRAF (V600E) mutation in PTC cases. Older age and no concurrent HT were independently associated with BRAF (V600E) mutation.

RESUMO Objetivo: Investigar a manifestação de sintomas do transtorno do processamento auditivo central em crianças com hipotireoidismo congênito. Métodos: Estudo de caráter exploratório, descritivo e transversal com 112 pacientes com hipotireoidismo congênito com idade ≥5 anos. Realizou-se entrevista com os pais/cuidadores no momento da espera da consulta médica. Portadores de outras afecções médicas foram excluídos. Como instrumento de pesquisa utilizou-se o protocolo estruturado de anamnese para avaliação do processamento auditivo rotineiramente empregado por audiologistas. A análise estatística utilizou o teste Qui-quadrado. Resultados: A distribuição por sexo foi semelhante (meninas: 53,3%). Os casos não-disgenesia constituíram a forma fenotípica mais prevalente para o hipotireoidismo congênito (88,4%), e verificou-se que 65,3% das crianças apresentavam algum episódio de níveis séricos irregulares de hormônio tireoestimulante. Dentre as manifestações mais frequentes dos sintomas do transtorno do processamento auditivo central, as queixas relaciondas às funções cognitivas auditivas, como: figura-fundo (83,0%), atenção auditiva (75,9%) e memória auditiva (33,0%) foram as mais evidentes. Reclamações relacionadas ao rendimento escolar foram reportadas em 62,3%. Conclusões: Os dados obtidos evidenciaram altas frequências de sintomas de defasagem nas funções cognitivas relacionadas ao processamento auditivo central, em especial na atenção auditiva, figura-fundo e memória auditiva nos portadores do hipotireoidismo congênito.

ABSTRACT Objective: To investigate the presence of central auditory processing disorder symptoms in children with congenital hypothyroidism. Methods: An exploratory, descriptive, cross-sectional study of 112 patients with congenital hypothyroidism aged ≥5 years old. An interview was held with the parents/caregivers at the time of the medical consultation. Patients with other medical conditions were excluded. As a research instrument, the structured protocol of anamnesis was used to evaluate the auditory processing routinely used by audiologists. For statistical analysis, the chi-square test was used. Results: Sex distribution was similar in both boys and girls (girls: 53.3%). The most prevalent phenotypic form of congenital hypothyroidism was no dysgenesis (88.4%), and 65.3% of the children had an episode of irregular serum thyroid-stimulating hormone (TSH) levels. Among the manifestations of the most frequent central auditory processing disorder symptoms, problems were reported with regard to cognitive functions, as they related to hearing, such as figure-background ability (83.0%), auditory attention (75.9%) and auditory memory (33.0%). Complaints related to school performance were reported in 62.3% of the cases. Conclusions: The data obtained show a high frequency of lag symptoms in cognitive functions related to central auditory processing, particularly with regard to auditory attention, figure-background ability and auditory memory in patients with congenital hypothyroidism.

ABSTRACT Objective: To evaluate the candidate genes PAX-8, NKX2-5, TSH-R and HES-1 in 63 confirmed cases of thyroid dysgenesis. Subjects and methods: Characterization of patients with congenital hypothyroidism into specific subtypes of thyroid dysgenesis with hormone levels (TT4 and TSH), thyroid ultrasound and scintigraphy. DNA was extracted from peripheral blood leukocytes and the genetic analysis was realized by investigating the presence of mutations in the transcription factor genes involved in thyroid development. Results: No mutations were detected in any of the candidate genes. In situ thyroid gland represented 71.1% of all cases of permanent primary congenital hypothyroidism, followed by hypoplasia (9.6%), ectopia (78%), hemiagenesis (6.0%) and agenesis (5.5%). The highest neonatal screening TSH levels were in the agenesis group (p < 0.001). Conclusions: Thyroid dysgenesis is possibly a polygenic disorder and epigenetic factors could to be implicated in these pathogeneses.

ABSTRACT Endocochlear, retrocochlear and/or central origin hearing damage may be related to the absence of appropriate levels of thyroid hormone during morphogenesis and/or auditory system development. Hearing disorders related to the thyroid are not well studied, despite speculation on the pathophysiological mechanisms. The objective of this review was to characterize the main pathophysiological mechanisms of congenital hypothyroidism and to evaluate the relationship with central and peripheral hearing disorders. We conducted a literature review using the databases MedLine, LILACS, Cochrane Library, SciELO, Institute for Scientific Information (ISI), Embase, and Science Direct between July and September on 2016. We identified the studies that address hearing disorder mechanisms on the congenital hypothyroidism. Congenital hypothyroidism may have clinical and subclinical manifestations that affect the auditory system and may be a potential risk factor for hearing impairment. Hearing impairment can severely impact quality-of-life, which emphasizes the importance of monitoring and evaluating hearing during the clinical routine of these patients.

Resumo Objetivo Investigar a frequência de sintomas otoneurológicos em crianças com hipotireoidismo congênito e relacioná-los com os aspectos clínicos. Métodos Estudo exploratório de caráter descritivo seccional. A casuística foi composta pelos pais e/ou cuidadores de 105 crianças com diagnóstico de hipotireoidismo congênito e com 5 anos ou mais de idade. A coleta de dados utilizou um questionário estruturado elaborado e testado pelos pesquisadores. As informações clínicas e laboratoriais foram obtidas dos prontuários médicos. Resultados A maioria dos indivíduos (72,4%) demonstrou sintomas relacionados à disfunção vestibulococlear, na qual a tontura/vertigem correspondeu a 56,2% dos sintomas, seguida pela hipoacusia (43,8%) e pelo zumbido (12,4%). Houve correlação estatística entre os sintomas de hipoacusia (p=0,016) e a idade para o teste de rastreio neonatal, bem como os sintomas de tontura/vertigem com a etiologia do hipotireoidismo congênito (p=0,003). Na percepção da hipoacusia (RP=0,49; IC=0,31-0,77), a exposição ao fator demonstrou associação com a probabilidade de 95%. Conclusão Os achados sugerem significativa prevalência e associação entre hipotireoidismo congênito e sintomas otoneurológicos, especialmente tontura, hipoacusia e zumbido.

Abstract Purpose To investigate the frequency of otoneurological symptoms in children with congenital hypothyroidism and correlate them to the clinical aspects. Methods Exploratory study of sectional descriptive character. The sample was composed by parents and/or caregivers of 105 children diagnosed with congenital hypothyroidism and age of 5 years or more. Data collection used a structured questionnaire developed and tested by researchers. Clinical and laboratory data were obtained from medical records. Results Most subjects (72.4%) showed symptoms related to vestibulocochlear disorder, in which dizziness/vertigo corresponded to 56.2% of symptoms, followed by hearing loss (43.8%) and tinnitus (12.4%). We observed statistical correlation between hearing loss (p = 0.016) and age of neonatal screening test, as well as symptoms of dizziness/vertigo with congenital hypothyroidism (p = 0.003). For hearing loss (PR = 0.49; CI = 0.31 to 0.77), the exposure factor showed a correlation with the probability of 95%. Conclusion These findings suggest a significant prevalence and association between congenital hypothyroidism and otoneurological symptoms, especially dizziness, hearing loss and tinnitus.

Objectives Iodine deficiency disorder (IDD) is the result of an inadequate dietary intake of iodine, which physiological consequences are endemic goiter and thyroid dysfunction. The objective of this study was to a analyze studies that assessed the status of Brazil’s population iodine nutrition and IDD prevalence. Materials and methods Systematic review using PRISMA statement. Electronic database: PubMed, Medline, SciELO and Lilacs. Quality of studies: Newcastle-Ottawa Scale. Meta-analysis was carried out with R Core Team Statistical Software, version 3.1.0 (2014). The summary measure (WMD) and its confidence interval (CI) of 95% were calculated. The “Funnel plot” graph assessed publication bias and heterogeneity. Results Seventeen papers were eligible: pregnant women (2), school children (9), adults/elderly (4) and preschool children/infants (2). Geographic distribution: North (1), Northeast (1), Midwest (2), Southeast (13), South (3). Twenty-three thousand two hundred seventy-two subjects were evaluated between 1997 and 2013 and all have use urinary iodine (UI) measurement. However, only 7 studies could be included in meta-analysis, all from Southeast region. The overall prevalence of IDD in school children in southeast region was 15.3% (95% CI, 13-35%), however this data had an important heterogeneity, expressed by the I2 Statistic of 99.5%. Conclusion Only few studies have been performed and enrolled populations from south/southeast region of Brazil. The actual IDD prevalence analysis is complex because it was detected bias due influence of individual studies and very high heterogeneity. IDD might still be high in some areas but this remained unknown even after this meta-analysis evaluation. The generation of a national program for analysis of iodine status in all regions is urgently required. Arch Endocrinol Metab. 2015;59(1):13-22

Objetivo Determinar, na América Latina, como os endocrinologistas lidam com cenários clínicos relacionados ao hipotireoidismo durante a gravidez. Materiais e métodos Em Janeiro de 2013, foi enviado, para 856 membros da Sociedade Latino-Americana de Tireoide (LATS), um questionário eletrônico sobre práticas relacionadas ao manejo do hipotireoidismo durante a gestação. Subsequentemente, as respostas foram analisadas. Resultados Duzentos e noventa e três médicos, de 13 países, responderam ao questionário. Todos estavam diretamente envolvidos no manejo de hipotireoidismo materno e 90,7% eram endocrinologistas. As recomendações de iniciar terapia com levotiroxina para uma mulher com hipotireoidismo franco durante a gravidez e o manejo na fase de pré-concepção de pacientes eutireoidianas com conhecida autoimunidade em hiperestimulação ovariana variaram amplamente. Para mulheres com hipotireoidismo conhecido, apenas 34,6% dos respondedores aumentariam a dose de levotiroxina em 30-50% assim que a gravidez fosse confirmada. Em relação ao rastreamento, 42,7% dos respondedores realizam avaliação universal. Setenta por cento recomendam TSH < 2,5 mUI/L no primeiro trimestre e TSH < 3 mUI/L no terceiro trimestre como alvos. Conclusão Observamos problemas no diagnóstico e manejo do hipotireoidismo durante a gestação, enfatizando a necessidade, na América Latina, de melhoria na educação médica continuada em áreas como tireoiodopatias na gestação. Arq Bras Endocrinol Metab. 2014;58(9):906-11

Objective To determine how endocrinologists in Latin America deal with clinical case scenarios related to hypothyroidism and pregnancy. Materials and methods In January 2013, we sent an electronic questionnaire on current practice relating to management of hypothyroidism in pregnancy to 856 members of the Latin American Thyroid Society (LATS) who manage pregnant patients with thyroid disease. Subsequently, we have analyzed responses from physician members. Results Two hundred and ninety-three responders represent clinicians from 13 countries. All were directly involved in the management of maternal hypothyroidism and 90.7% were endocrinologists. The recommendation of a starting dose of L-thyoxine for a woman diagnosed with overt hypothyroidism in pregnancy, preconception management of euthyroid women with known thyroid autoimmunity and approach related to ovarian hyperstimulation in women with thyroid peroxidase antibodies were widely variable. For women with known hypothyroidism, 34.6% of responders would increase L-thyroxine dose by 30-50% as soon as pregnancy is confirmed. With regard to screening, 42.7% of responders perform universal evaluation and 70% recommend TSH < 2.5 mUI/L in the first trimester and TSH < 3 mUI/L in the second and third trimester as target results in known hypothyroid pregnant women. Conclusion Deficiencies in diagnosis and management of hypothyroidism during pregnancy were observed in our survey, highlighting the need for improvement of specialist education and quality of care offered to patients with thyroid disease during pregnancy in Latin America. Arq Bras Endocrinol Metab. 2014;58(9):906-11

Fundamento: O hipertireoidismo (Hi) exerce um amplo leque de influências em diversos parâmetros fisiológicos. Seu efeito perturbador sobre o sistema cardiovascular é um de seus impactos mais importantes. Além disso, o Hi foi clinicamente associado com o estresse induzido pela hiperativação do eixo hipotalâmico-pituitário-adrenal. Objetivo: Avaliar o impacto do Hi de curto prazo sobre o desempenho cardíaco e a atividade adrenal de ratos. Métodos: A indução de Hi em ratos Wistar através de injeções de T3 (150 μg/kg) por 10 dias (grupo com hipertireoidismo - GH) ou veículo (grupo controle). O desempenho cardiovascular foi avaliado por: ecocardiograma (ECO); razão peso do coração/peso corporal (mg/gr); contratilidade de músculos papilares isolados (MPI) e mensuração direta da pressão arterial. A atividade adrenal foi avaliada pela razão peso adrenal/ peso corporal (mg/gr) e níveis de 24 horas de corticosterona fecal (CF) no 1º, 5º e 10º dias de tratamento com T3. Resultados: No GH, o ECO mostrou redução dos Volumes Finais Sistólico e Diastólico, Tempos de Ejeção, Relaxamento Isovolumétrico e Diastólico Total, Áreas Sistólicas e Diastólica e razão E/A. Aumentaram a frequência cardíaca, a fração de ejeção e o débito cardíaco. A razão peso corporal/peso do coração foi maior. Da mesma forma, nos MPI, a taxa máxima de degradação da força durante o relaxamento foi maior em todas as concentrações extracelulares de cálcio. Os níveis de pressão arterial sistólica (PAS) foram maiores. (p ≤ 0,05). Por outro lado, não houve diferença na razão peso das adrenais/peso corporal ou níveis de 24 horas de CF. Conclusões: O Hi induz efeitos inotrópicos, cronotrópicos e lusitrópicos positivos no coração através de efeito direto do T3, e aumenta a PAS. Essas alterações não estão correlacionadas com as alterações na atividade adrenal.

Background: Hyperthyroidism (Hy) exerts a broad range of influences on a variety of physiological parameters. Its disruptive effect on cardiovascular system is one of its most remarkable impacts. Moreover, Hy has been clinically associated with stress - induced hyperactivation of the hypothalamic-pituitary-adrenal axis. Objective: Evaluate the impact of short-term Hy on cardiac performance and adrenal activity of rats. Methods: Induction of Hy in Wistar rats through injections of T3 (150 µg/kg) for 10 days (hyperthyroid group - HG) or vehicle (control group). The cardiovascular performance was evaluated by: echocardiography (ECHO); heart weight/body weight (mg/gr) ratio; contractility of isolated papillary muscles (IPM) and direct measurement of blood pressures. Adrenal activity was evaluated by adrenal weight/body weight (mg/gr) ratio and 24-hour fecal corticosterone (FC) levels on the, 5th and 10th days of T3 treatment. Results: In HG, the ECHO showed reduction of the End Systolic and End Diastolic Volumes, Ejection, Total Diastolic and Isovolumic Relaxation Times, Diastolic and Systolic Areas and E/A ratio. Heart Rate, Ejection Fraction and Cardiac Output increased. The heart weight/body weight ratio was higher. Similarly, in IPM, the maximum rate of force decay during relaxation was higher in all extracellular calcium concentrations. Systolic blood pressure (SBP) levels were higher. (p ≤ 0.05). On the other hand, there was no difference in the adrenal weight/body weight ratio or in the 24-hour FC levels. Conclusions: Hy induces positive inotropic, chronotropic and lusitropic effects on the heart by direct effects of T3 and increases SBP. Those alterations are not correlated with changes in the adrenal activity.