Thyroid gland dysfunction is a risk factor for development of cardiovascular diseases. From all types of thyroid gland dysfunction hypothyroidism is the most common. Increasing of thyroid-stimulating hormone level can influence the clinical course of chronic heart failure (CHF) because of its extrathyroid effects - namely - influence on lipide metabolism, endothelial function of vessels and blood pressure. Also CHF itself can make negative impact on a thyroid gland functioning, therefore pathophysiological "vicious circle" is formed. Manifest hypothyroidism is associated with an increased risk of general and cardiovascular mortality and frequency of hospitalizations of CHF patients. Association between subclinical hypothyroidism and heart failure is less studied. Figuring out the mechanisms of influence of thyroid gland hypofunction on systolic and diastolic function of myocardium may be important for effective treatment of heart failure and improvement of clinical outcomes.

MeSH words: heart failure; hypothyroidism; thyroid-stimulating hormone (TSH); review.