Primary hypothyroidism is one of the most common endocrine pathologies. Subclinical hypothyroidism (SH) is a common disorder diagnosed with elevated levels of thyroid-stimulating hormone (TSH) and normal serum free thyroxine (T4) levels. There are also the difficulties in diagnosing SH due to its low-symptomatic or asymptomatic course and numerous “masks”: cardiological, gastroenterological, rheumatological, hematological, psychiatric. A wide variety of causes also makes timely diagnosis difficult.There are many studies proving the effect of SH on the state of the cardiovascular system (CVS) and its association with a higher risk of cardiovascular events. Diastolic dysfunction and arterial hypertension (AH) are commonly observed. Of note, the issue of prescribing replacement therapy with Levothyroxine sodium is still controversial. It is necessary to conduct further research in order to develop unified algorithms for the treatment of patients with FH, including those with concomitant cardiovascular diseases (CVD).CVD is a frequent companion of hypothyroidism. The studies on FH replacement therapy are of low methodological quality and their conclusions on the outcomes of interest are not consistent. Thus, further studies with a large number of patients are required to identify the effect of FH on the state of the CVS.In this review, the authors summarize and present the available data on the incidence, pathogenetic mechanisms, cardiovascular pathology in HF, as well as its treatment.