Abstract 1582: Effects of Sleeping on Left Ventricular Systolic Function in Obstructive Sleep Apnea Syndrome: Quantitative Assessment Using Tissue Doppler Echocardiography
Background: Although LV diastolic dysfunction is frequently observed in patients with obstructive sleep apnea syndrome (OSAS), the effects of this condition on LV systolic function remains unclear. The aim of this study was to determine in OSAS patients the effects of sleeping on LV longitudinal function using tissue Doppler imaging (TDI).
Methods: In 40 OSAS patients with normal LVEF and 18 control subjects, TDI, standard 2D and Doppler echocardiography were acquired before and immediately after overnight sleep. Septal and lateral mitral annular velocities were recorded using pulse-wave Doppler using TDI in the apical 4-chamber view. Peak systolic (S′), early diastolic (E′) and late diastolic (A′) annular velocities were measured and averaged.
Results: In OSAS patients:
the prevalence of hypertension was higher (40% vs. 6%, p<0.01),
LV mass index was higher (106±18 vs. 94±20 g/m2, p<0.03) and
left atrial volume index was larger (26.6±5.3 vs. 22.7±3.8 ml/m2, p<0.01).
Before sleeping, OSAS patients had faster HR with prolonged IVRT and deceleration times suggesting impaired relaxation. In OSAS patients, no significant differences in S′ were noted, but E′ was lower and A′ was higher compared to control subjects. In both groups, compared to before sleeping, S′ and E′ were significantly reduced after sleeping, but the % reduction of S′ (21.6±12.5% vs. 8.3±10.6%, p<0.001) was significantly larger in OSAS patients. The significant reduction of A′ was only observed in OSAS patients. After overnight sleep, IVRT was further prolonged and A wave velocity significantly reduced in OSAS patients. No differences in LVEF were noted before and after the sleeping in both groups.
Conclusions: Overnight sleeping in OSAS patients is associated with the development of subclinical systolic dysfunction accompanied with worsened diastolic dysfunction. Impairment of A′ and A wave velocities might contribute towards the development of atrial fibrillation in OSAS patients.