Brazil lacks large cohort studies with analyses of incidence and prevalence of diseases in all areas. In this context, the ELSA-Brasil study was an important milestone for the evaluation of cardiovascular diseases in the country. This study shows a very detailed means of exposing relevant facts to the occurrence or not of arrhythmogenic electrocardiographic manifestations in patients with subclinical thyroid hormone disorders. This issue is extremely relevant, has biological plausibility and generates several doubts regarding the patient.

The study included a relevant sample of 13,341 patients in total, with a mean age of 51 years. The data collection, electrocardiographic specifications and laboratory tests were protocolized according to predetermined and uniform specifications in all patients. Moreover, they were comprehensively evaluated, from arrhythmias supposedly more frequent in thyroid disorders such as atrial fibrillation, plus basal heart rate, presence of extrasystoles and conduction intervals.

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