[The relation between the low T3 syndrome in the clinical course of myocardial infarction and heart failure].

It has been proven that either excess or deficiency of thyroid hormones has harmful influence on the cardiovascular system function. On the other hand, severe systemic conditions like myocardial infarction or severe heart failure may affect thyroid hormones secretion and their peripheral conversion, leading to low T3 syndrome. Amongst many mechanisms causing T4 to T3 conversion disturbances, important role plays decreased activity of D1 deiodinase and increased activity of D3 deiodinase.

[Thyroid hormone and the cardiovascular system].

It is well established that thyroid hormones affect the cardiovascular system through genomic and nongenomic actions. TRalpha1 is the major thyroid hormone receptor in the heart. T3 suppresses increased mitotic activity of stimulated cardiomyocytes.

[Classification and etiology of hyperthyroidism].

The prevalence of hyperthyroidism in women is between 0.5-2% and it is 10 times less common in men. The most common causes are Graves' disease, toxic multinodular goiter, and autonomously functioning thyroid adenoma.

[Amiodarone treatment and thyroid disorders].

Amiodarone is a benzofuranic iodine-rich antiarrhythmic drug used in the treatment of severe tachyarrhythmias, especially ventricular. Drug causes many adverse effects including thyroid disorders in 14-18% of patients: amiodarone induced thyrotoxicosis type I and type II (AIT I, AIT II) and amiodarone induced hypothyroidism (AIH). AIT occurs more frequently in geographical areas with low iodine intake, whereas AIH is more frequent in iodine-sufficient areas.