In recent years, several scientific papers have highlighted the role of the thyroid system in cardioprotection, and several clinical studies   including multicenter studies   have identified the role of thyroid hormones (TH) in the development and progression of cardiovascular disease, making an update of TH and heart relationship both necessary and timely.  This second edition of Thyroid and Heart failure provides a careful and updated review of the experimental, clinical and epidemiological results in the field of TH and heart failure, with a particular focus on the translational - bench to bedside - significance of the obtained results. It discusses topics such as the molecular, structural, functional, cellular and histological cardiac changes; the reversibility of these changes with TH replacement therapy; the systemic effects   kidney, hormonal pathways systems, brain, muscle, etc   of altered TH metabolism in HF, as well as the clinical and prognostic implications.