Background: The mechanisms of increased left ventricular mass (LVM) in hyperthyroidism are complex. The aim was to determine the effects of hyperthyroidism and thyreostatic therapy on LVM regarding its interrelationship with factors responsible for the heart’s hemodynamic workload.
Material/Methods: The study included 51 hyperthyroid subjects and 30 healthy controls. Left heart ventricle parameters evaluated using standard ultrasonocardiography were: left ventricular volume (end-systolic and end-diastolic), left ventricle posterior wall thickness at systole (LVPWs) and diastole (LVPWd) with the respective interventricular septal thicknesses (IVSs, IVSd), LVM, stroke volume (SV), cardiac output (CO), output–pressure index (OPI), and total peripheral resistance (TPR). Systolic
(SBP) and diastolic (DBP) blood pressure, heart rate (HR), and body mass index (BMI) were investigated.
Measurements were repeated after two weeks of thiamazole treatment and after attaining
euthyreosis.
Results: Compared with controls, the hyperthyroid subjects had signifi cant thickening of LVPWd, LVPWs,
and IVSs, increased LVM, augmented SV, CO, OPI, SBP, and HR, but reduced TPR and DBP. Hyperthyroid treatment did not normalize LVM. LVM showed positive correlations with SV, CO, OPI, SBP, BMI, and serum triiodothyronine concentration and negative correlation with TPR. In multivariate regression analysis, LVM correlated with SBP, SV, and BMI (R=0.64, p

Keywords: Blood Pressure, Case-Control Studies, Echocardiography, Heart Rate, Heart Ventricles - pathology, Hyperthyroidism - complications, Hypertrophy, Left Ventricular - pathology, Stroke Volume, Thyroid Hormones - blood, Thyrotropin - blood