Endocrine Abstracts

Introduction: Changes in thyroid function have significant impact on the cardiovascular system.

Methods: In a group of 37 subjects the level of thyroid hormones FT₄, FT₃, and TSH were measured. Then carried out short-term analysis for 30 min measureing variability of blood pressure with non-invasive TASK FORCE monitor. Registered data were analyzed by spectral analysis of variability. Statistical analysis were done by Pearson correlation model.

Results: The analysis of the parameters of the variability of systolic blood pressure (SBP), we confirmed that FT₄ positively correlated with parameters of spectral analysis of variability of systolic blood pressure: sBP LF; sBP LF/HF (P<0.05), sBP LF, sBP PSD (P<0.001). Discovered a negative correlation with sBP HF nu (P<0.05). FT₃ is positively correlated with parameters of systolic blood pressure variability: sBP LF nu, sBP LF, sBP PSD, sBP LF/HF (<0.05). TSH is positively correlated with SBP HF nu (r=0.4379) and HF SBP (P<0.05).

The analysis of correlation with thyroid hormone parameters of diastolic blood pressure variability has been found for FT₃ – negatively correlated with DBP HFnu (P<0.5) and positive correlation with DBP LF (P<0.05).

Conclusion: Our study demonstrates a significant correlation between thyroid hormones with a systolic blood pressure and less important correlation with parameters of diastolic blood pressure variability. The analysis of variability of systolic blood pressure observed a positive correlation between FT₄ and FT₃ with parts of the spectrum of low frequency (sympathetic activity) and total spectral power (PSD). FT₄ and FT₃ were in negative correlation with parts of the spectrum of high frequency (parasympathetic). TSH correlated positively with the parasympathetic nervous system.

Analysis of variability of diastolic blood pressure registered a small number of significant correlations and FT₃ – negatively correlated with DBP HFnu (P<0.5) and positive correlation with DBP LF (P<0.05).