Thyroid hormone and cardiovascular system: from basic concepts to clinical application

Experimental and clinical findings strongly support the concept that thyroid hormone (TH) plays a fundamental role in the cardiovascular (CV) homeostasis. CV diseases represent a major public health care and economic problem being one of the principal causes of morbility, mortality and hospitalization. In particular, chronic heart failure (HF) is one of the most common reasons for general practitioners consultations in people >65-70 years old. TH derangement may have a key role in the evolution process of HF. In HF, the main and earlier alteration of the thyroid function is referred to as "low-T3" syndrome characterized by the reduction in serum total T3 and free T3 with normal levels of thyroxine (T4) and thyrotropin (TSH). This syndrome may affect till one-third of advanced HF patients. The main goal of this mini-review is to examine the main pathophysiological and clinical links between an altered thyroid metabolism and CV diseases, namely HF during progression of disease from organ specific to systemic disorder.