Assessment of left atrial mechanical functions in thyroid dysfunction.

Introduction:  Thyroid hormone deficiency can lead to the impairment of cardiac function.

Objectives:  The aim of the study was to determine the left atrial (LA) mechanical function in patients with subclinical hypothyroidism (SHT) and overt hypothyroidism (OHT) and investigate associations of LA mechanical function with diastolic function. 

Patients And Methods:  Twenty‑six patients with newly diagnosed SHT (mean age, 42.2 ±12.5 years), 21 patients with OHT (40.2 ±8.5 years) and 28 healthy volunteers (42.4 ±11.2 years) were enrolled in this study. Patients were evaluated by standard M‑mode echocardiographic measurements, mitral Doppler flow analysis, and tissue Doppler parameters at the lateral, septal, and right ventricular annuli. LA volumes were measured using the disc method, and the parameters of LA mechanical function were calculated. 

Results:  The active emptying volume (AEV) and active emptying fraction (AEF) were significantly higher in the OHT and SHT groups compared with controls. The passive emptying volume and passive emptying fraction were lower in the OHT and SHT groups compared with controls, but the differences were not significant. The conduit volume and the E/A ratio were significantly lower in the OHT and SHT groups compared with controls. The lateral and septal E/Em were significantly higher in the OHT and SHT groups than in the control group, but the septal Em/Am was significantly lower. Diastolic function parameters showed significant associations with AEV and AEF. 

Conclusions:  LA mechanical function is impaired in patients with thyroid dysfunction. Our findings suggest that this impairment is secondary to that of the left ventricular diastolic function.