The Management of Thyroid Abnormalities in Chronic Heart Failure.

KEY POINTS Normal triiodothyronine (T3) levels are essential to preserve cardiac morphology and function. Overt and subclinical hypothyroidism are associated with an increased risk of heart failure, and levothyroxine is able to improve cardiovascular function in hypothyroid patients. Low T3 syndrome can develop in patients with advanced heart failure and is associated with a negative prognosis. Low T3 syndrome is associated with alterations in thyroid hormone receptors expression, contributing to the development of a cardiac fetal phenotype, leading to cardiac dysfunction. The positive effects of treatment with thyroid hormones in patients with low T3 and heart failure support their potential therapeutic approach in heart failur