ECG changes in patients with primary hyperthyroidism

Assessment of Electrocardiographic Changes and Associated Factors Among Thyroid Dysfunction Patients Attending Jimma Medical Center, Southwest Ethiopia: A Cross-Sectional Study

Background

Thyroid dysfunction (TD) is a metabolic manifestation related to either excessive or inadequate production of thyroid hormones. It has been widely proven to have comorbidities like cardiovascular disease. An electrocardiograph is a simple investigative instrument used to assess cardiac status to prevent complications in the later stages of the disease.

Objective

To assess electrocardiogram (ECG) changes and associated factors among TD patients.

Methods

An institution-based cross-sectional study was conducted among 273 TD patients attending Jimma Medical Center from October 11 to December 11, 2021. An ECG tool with 12 leads was used to assess the cardiac status, and a semi-structured questionnaire was used to assess sociodemographic, behavioral, and comorbidity variables. Bodyweight, height, waist circumference (WC), hip circumference (HC), and blood pressure variables were recorded, and body mass index (BMI) and waist-to-hip ratio (WHR) were calculated.

Results

Out of a total of 273 analyzed and interpreted ECG results by the cardiologists, 185 (67.8%) had ECG alterations. The most common types of ECG changes were arrhythmia 153 (56%), followed by myocardial infarction 74 (27.1%), ventricular hypertrophy [left 20 (7.3%) and right 15 (5.5%)], left atrial enlargement 3 (1%), axis deviation, and other abnormalities 24 (8.8%) and 18 (6.6%), respectively. The identified predictor variables for the ECG changes were the age group of 41 to 60 years old [AOR = 2.5, 95% CI: 1.25, 5.05], being female [AOR = 2.7, 95% CI: 1.28, 5.59], having diabetes mellitus [AOR = 4.25, 95% CI: 1.6, 11.2], and not starting the treatment [AOR = 8.6, 95% CI: 3.45, 21.6].

Conclusion

This study revealed that the prevalence of ECG changes was high among TD patients. The most common type of ECG change observed was arrhythmia followed by myocardial infarction. The age range of 41-60 years old, being female, having diabetes mellitus, and not starting the treatment were significantly associated with the ECG changes. Implementing an efficient noninvasive screening of cardiac status can detect unrecognized and asymptomatic cardiac impairment in TD patients.

Cardio-Thyrotoxicosis Syndrome: A Review of Thyrotoxic Cardiovascular Disease

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

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

Background

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

Methods

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

Results

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

Conclusion

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

A systematic review and meta-analysis of the etiology and treatment patterns of thyrotoxicosis in Africa

INTRODUCTION

Thyrotoxicosis is one of the most common endocrine disorders seen in clinical practice. This study aims to determine the etiologies and treatment modalities of thyrotoxicosis in Africa.

AREAS COVERED

The study design is a systematic review with a meta-analysis. Medical databases and the gray literature were systematically searched following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies done in Africa on the etiology and treatment of thyrotoxicosis were selected.

EXPERT OPINION

In Africa, it is still believed that autoimmune diseases, generally, are not as common as what is seen in the western world. The frequency of Graves' disease is reportedly lower in Africa. The treatment of thyrotoxicosis depends on the cause. Therefore, it is of substantial importance to establish the etiology following the diagnosis of the clinical syndrome.

Levothyroxine Treatment and the Risk of Cardiac Arrhythmias - Focus on the Patient Submitted to Thyroid Surgery

Levothyroxine (LT4) is used to treat frequently encountered endocrinopathies such as thyroid diseases. It is regularly used in clinical (overt) hypothyroidism cases and subclinical (latent) hypothyroidism cases in the last decade. Suppressive LT4 therapy is also part of the medical regimen used to manage thyroid malignancies after a thyroidectomy. LT4 treatment possesses dual effects: substituting new-onset thyroid hormone deficiency and suppressing the local and distant malignancy spreading in cancer. It is the practice to administer LT4 in less-than-high suppressive doses for growth control of thyroid nodules and goiter, even in patients with preserved thyroid function. Despite its approved safety for clinical use, LT4 can sometimes induce side-effects, more often recorded with patients under treatment with LT4 suppressive doses than in unintentionally LT4-overdosed patients. Cardiac arrhythmias and the deterioration of osteoporosis are the most frequently documented side-effects of LT4 therapy. It also lowers the threshold for the onset or aggravation of cardiac arrhythmias for patients with pre-existing heart diseases. To improve the quality of life in LT4-substituted patients, clinicians often prescribe higher doses of LT4 to reach low normal TSH levels to achieve cellular euthyroidism. In such circumstances, the risk of cardiac arrhythmias, particularly atrial fibrillation, increases, and the combined use of LT4 and triiodothyronine further complicates such risk. This review summarizes the relevant available data related to LT4 suppressive treatment and the associated risk of cardiac arrhythmia.

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

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