Effect suppresive therapy with levothyroxine on the state of the cardiovascular and sympathoadrenal systems

Thyroid hormones can affect the cardiovascular system directly by binding to nuclear thyroid receptors, as well as indirectly by changing the neuro – humoral status of the body as a whole. The aim of the work was to assess the effect of levothyroxine suppressive therapy on the regulation of the heart rate and activity of the sympathoadrenal system, as well as the level of cortisol in the blood of young patients with thyroid cancer. It is shown that the effect of suppressive therapy with levothyroxine on the state of the cardiovascular system is manifested in an increase in the risk of tachycardia and changes in heart rate variability associated with the body mass index. Patients with thyroid cancer had a sharp decrease in normetanephrine (norepinephrine metabolite) in the urine. The levels of metanephrine (metabolite of adrenaline) and dopamine in the urine was dependent on the tonus of the autonomic nervous system and blood pressure. The revealed shifts indicate that against the background of subclinical hyperthyroidism, the mechanisms aimed at stabilizing the heart rate and preventing the effects of hyperstimulation of thyroid and beta-adrenoreceptors of the myocardium are included.