October - December 2014, Volume 10, Issue 4

Tanase DM, Vulpoi C, Ionescu SD, Ouatu A, Ambarus V, Arsenescu-Georgescu C

Effects of Subclinical and Overt Primary Hypothyroidism on the Cardiac Function and their Reversibility under Treatment Using Tissue Doppler Echocardiography

Acta Endo (Buc) 2014, 10 (4): 640-654
doi: 10.4183/aeb.2014.640

Background. The modifications of blood pressure and lipid metabolism, the decrease of heart contractility and the increase of systemic vascular resistance that accompany hypothyroidism are caused by the decreased action of thyroid hormones. Objective. The purpose of this study is to evaluate, using echocardiography, the changes of the heart functional parameters in patients with untreated thyroid dysfunctions. Pacients and Methods. Study group included 348 patients for an evaluation of cardiovascular and thyroid status. The control of the thyroid condition was conducted using measurements of the FT3, FT4 and TSH levels, echocardiographic measurements defining the parameters of the function of the left ventricle. Results. The study group was divided into subclinical hypothyroidism (SH, 75 cases), overt hypothyroidism (OH, 123 patients) and normal thyroid function (C, 150 patients). TSH values decreased (from 5.8±15 mUI/L to 2.28±0.63 mUI/L in SH and from 20.23±17.33 mUI/L to 4.24±0.24 mUI/L in OH) after one year of treatment while fT4 and fT3 increased. The parameters obtained revealed significant decreases of the E/A ratio in both groups with hypothyroidism. The isovolumetric relaxation time was significantly higher in SH and OH as compared to the control group (C: 112.50±35.45 msec, SH: 118.75±16.52 msec p<0.05, OH: 130±41.83 msec p<0.001). In addition, the tissue Doppler revealed significant decreases of the E’/A’ ratio, measured septally and laterally in the group with overt and subclinical hypothyroidism. Conclusion. In hypothyroidism the systolic and predominantly diastolic function of the left ventricle are impaired. These dysfunctions are reversible under L-T4 substitutive treatment.

Keywords: hypothyroidism, systolic function, diastolic function, echocardiography

Correspondence: Daniela Maria Tanase MD, “Gr. T. Popa” University of Medicine and Pharmacy Internal Medicine, Universitatii Street, No. 16, Iasi, 700115, Romania, E-mail: tanasedm@gmail.com