To investigate the early changes of left atrial structure and function using echocardiography in obstructive sleep apnea syndrome(OSAS) patients with and without left ventricular hypertrophy(LVH).

Echocardiography was performed in 91 OSAS patients (64 without LVH, 27 with LVH), and the results were compared with those from age-matched and gender-matched controls (n=40). All subjects were examined with two-dimensional speckle tracking echocardiography (2D-STE) to obtain the apical four chamber and two chamber left atrium(LA) strain and strain rate curve image. Systolic strain and strain rate(Ss, SRs), early diastolic strain and strain rate(Se, SRe), late diastolic strain and strain rate(Sa, SRa) were measured. Phasic LA volumes and empty fractions were calculated. The ratio of peak early diastolic mitral inflow and annulus velocity(E/e′) was used to estimate left ventricular diastolic function.

Compared with the control group, LA volume, LA stiffness index, SRa and active empyting fraction (AEF) increased, Ss, SRs, Se, SRe, total empyting fraction (TEF) and passive empyting fraction (PEF) decreased in none LVH group (P<0.05). Importantly, diastolic function was relatively normal in this subgroup without LVH(P>0.05). Diastolic function decreased in LVH group, and the changes of left atrial structure and function like above mentioned were more significant.The apnea-hypopnea index (AHI) was found to be negatively correlated with Ss, SRs, Se, SRe, TEF and PEF.

OSAS is associated with LA remodeling and dysfunction that occurs before the development of LVH and left ventricular diastolic dysfunction, and it will be further aggravated along with the development of LVH.

Two-dimensional speckle tracking imaging; Sleep apnea, obstructive; Atrial function, left