Subclinical hyperthyroidism impacts left ventricular deformation: 2D and 3D echocardiographic study

Background. We sought to investigate left ventricular (LV) function and mechanics assessed by three-dimensional echocardiography (3DE) and speckle tracking in patients with subclinical hyperthyroidism (SCH). Methods. We included 35 untreated women with SCH and 35 healthy control women matched by age. All participants underwent laboratory analyses which included thyroid hormone levels, and complete 2DE and 3DE examination. Results. 2DE LV longitudinal and circumferential strain was significantly decreased in the SCH subjects. 2DE LV systolic and early diastolic strain rates in longitudinal and circumferential directions were reduced, whereas late diastolic strain rates were increased in SCH individuals. 3DE LV end-diastolic volume and cardiac output were significantly elevated in the SCH patients. 3DE LV deformation in all three directions, as well as 3DE area strain, were significantly lower in the SCH group. Serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels correlated with 2DE LV mass index, 2DE longitudinal strain, and 3DE LV area strain in the whole study population. Conclusion. LV deformation evaluated by 3DE and speckle tracking imaging are significantly impaired in SCH subjects. TSH and FT4 levels correlate with 2DE and 3DE LV structure and mechanics.