Participation of the pituitary-thyroid axis in the cardiovascular system in elderly patients with congestive heart failure

The relationship between the pituitary-thyroid axis and the cardiovascular system in patients with congestive heart failure (CHF) remains unknown. Therefore, we attempted to determine serum levels of thyroid hormones in relation to plasma atrial natriuretic peptide (ANP) levels and left ventricular (LV) function in patients with CHF. The echocardiographic ejection fraction significantly correlated with the thyroid stimulating hormone (TSH) (p0.005) and free triiodothyronine (FT3)/free thyroxine (FT4) ratio (p0.005), respectively, in patients with CHF but not in control subjects. TSH was positively correlated with the FT3/FT4 ratio (p0.01) in CHF. In patients with CHF, TSH and thyroid hormones may participate in regulatory mechanisms of the cardiovascular system and altered thyroid hormone metabolism, which was characterized by a euthyroid sick syndrome.