Ultrasonic myocardial textural analysis in subclinical hypothyroidism

Background: In subclinical hypothyroidism (sHT), a condition in which impaired hormone synthesis is compensated by thyroid-stimulating hormone (TSH) hypersecretion, previous studies have suggested the presence of disturbances in left ventricular (LV) function. Objectives: Our goal was to investigate LV structure and function through the combined use of conventional Doppler echocardiography and ultrasonic videodensitometry. Methods: We studied 16 patients with sHT (aged 32 ± 12 [mean ± SD] years) who had raised TSH levels (> 3.6 mIU/L) but normal levels of free thyroid hormones (free thyroxine [FT4] and free triiodothyro-nine [FT3]), and 16 carefully age- and sex-matched euthyroid subjects. Transmitral flow Doppler analysis and quantitative analysis of the echocardiographic digitized images were performed in all study subjects. Textural parameters of the septum and posterior wall were obtained as mean gray levels, which were then used to calculate the cyclic variation index (CVI), that is, the percent change in mean gray levels between diastole and systole. Results: Patients with sHT had a significantly higher LV mass index (92 ± 16 versus 76 ± 16 g·m2, P