Thyroid hormones have relevant activity at cardiac and vascular level, by 
influencing heart rate, myocardial excitability as well as inotropic and 
lusitropic status, systemic vascular resistance and blood pressure. Moreover, 
they interact with neuro-hormonal systems such as sympathetic nervous system and 
renin-angiotensin-aldosterone system thus also indirectly influencing 
cardiovascular function. Due to these effects, both hypothyroidism and 
hyperthyroidism, either in their overt or subclinical forms, can have an 
unfavourable impact in the setting of cardiovascular diseases. The aim of this 
review is to focus on the prognostic consequences of thyroid disorders in heart 
failure patients. Moreover, the therapeutical approach and the possible 
beneficial effects of restoring euthyroidism are reviewed.