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Participation of the pituitary-thyroid axis in the cardiovascular system in elderly patients with congestive heart
T Kimura1, T Kanda, A Kuwabara
1Department of Laboratory Medicine, Gunma University School of Medicine, Japan.
Insights
Thyroid hormones and thyroid stimulating hormone (TSH) are linked to cardiovascular function in congestive heart failure (CHF). These findings suggest a role for the pituitary-thyroid axis in CHF
Area of Science:
- Cardiology
- Endocrinology
- Internal Medicine
Background:
- The interplay between the pituitary-thyroid axis and cardiovascular function in congestive heart failure (CHF) is not well understood.
- Thyroid dysfunction is common in patients with cardiovascular disease, but its specific role in CHF pathogenesis requires further investigation.
Purpose of the Study:
- To investigate the relationship between thyroid hormone levels, atrial natriuretic peptide (ANP), and left ventricular (LV) function in patients with CHF.
- To explore potential regulatory mechanisms of the cardiovascular system involving the pituitary-thyroid axis in CHF.
Main Methods:
- Serum thyroid hormone levels (TSH, FT3, FT4) and plasma ANP were measured in patients with CHF and control subjects.
- Echocardiography was performed to assess left ventricular (LV) function, including ejection fraction.
- Statistical analysis was used to determine correlations between thyroid hormones, ANP, and LV function parameters.
Main Results:
- Echocardiographic ejection fraction significantly correlated with thyroid stimulating hormone (TSH) and the free triiodothyronine (FT3)/free thyroxine (FT4) ratio in CHF patients, but not in controls.
- TSH showed a positive correlation with the FT3/FT4 ratio in patients with CHF.
- These findings suggest altered thyroid hormone metabolism, consistent with euthyroid sick syndrome, in CHF patients.
Conclusions:
- The pituitary-thyroid axis, including TSH and thyroid hormones, appears to play a role in the cardiovascular regulatory mechanisms of CHF.
- Altered thyroid hormone metabolism, characterized by euthyroid sick syndrome, is evident in patients with CHF.
- Further research is warranted to elucidate the precise mechanisms and clinical implications of these findings.
Abstract:
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) (p < 0.005) and free triiodothyronine (FT3)/free thyroxine (FT4) ratio (p < 0.005), respectively, in patients with CHF but not in control subjects. TSH was positively correlated with the FT3/FT4 ratio (p < 0.01) 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.