Abstract
Objectives: Autoimmune thyroiditis (AT) with subclinical hypothyroidism (SH) might be associated with alterations in cardiac global left ventricular (LV) function; its impact on myocardial regional systolic and diastolic function and on arterial stiffness is less clear. Aim of this study was to investigate the effects of SH on segmental LV and arterial functions.
Methods: We studied regional LV function by tissue Doppler imaging (TDI), arterial stiffness by ultrasound assessment of distensibility coefficient (DC) and Young`s elastic modulus, as well as biochemical parameters in 53 middle-aged women. 15 of them were euthyroid but had elevated levels of circulating antithyroid antibodies and changes typical of AT by thyroid ultrasound. 20 patients had AT and SH. Results were compared with those obtained in 18 euthyroid women with endemic goiter (controls).
Results: Segmental LV diastolic function was impaired in patients with SH compared with euthyroid patients and controls (dysfunctional segments were found in 40%, 20% and 5.6% patients retrospectively, p=0.039) whereas there were no differences in regional systolic function (p>0.05). Subclinical hypothyroid patients presented higher Young`s elastic modulus (p=0.049) and lower DC (p=0.060), indicating increased arterial stiffness in these subjects. Young`s elastic modulus values were positively correlated with the number of dysfunctional segments by TDI (R=0.32, p=0.048), and negatively with T4 values (R=- 0.49, p=0.049).
Conclusions: Our data suggest that SH is associated with an impairment of regional LV diastolic function and increased arterial wall stiffness. The observed abnormalities in arterial stiffness appear to contribute to the segmental diastolic dysfunction in patients with SH.