Aims: Although left ventricular (LV) diastolic dysfunction is frequently observed in patients with obstructive sleep apnoea (OSA), the effects of overnight sleeping on LV function remain unclear. The aim of this study was to determine acute effects of overnight sleeping on LV function in OSA patients.
Methods and results: In 29 OSA patients with normal LVEF and 20 control subjects, tissue Doppler imaging (TDI), standard 2D, and Doppler echocardiography were acquired before and immediately after overnight sleep. Peak systolic (S'), early diastolic (E'), and late diastolic (A') annular velocities at septal and lateral corners were measured and averaged. The prevalence of hypertension was more often, LV mass index (102 +/- 16 vs. 89 +/- 18 g/m(2), P < 0.05) and left atrial volume index (25.3 +/- 4.0 vs. 22.3 +/- 4.4 mL/m(2), P < 0.05) were larger in OSA patients. Before sleeping, OSA patients had reduced E/A ratio suggesting impaired relaxation. Although no significant differences in S' were noted between the two groups, E' was lower and A' was higher in OSA patients compared with control subjects. Compared with before sleeping, S', E', and A' were significantly reduced after sleeping in both groups, but the per cent reduction of S' and A' was significantly larger in OSA patients. After overnight sleep, A wave velocity was also significantly reduced in OSA patients. A weak but significant correlation between per cent reduction of S'(A') and apnoea-hypopnoea index was noted.
Conclusion: Overnight sleeping in OSA patients is associated with the development of subclinical systolic dysfunction and exaggerated diastolic dysfunction.