A Study On The Diastolic Function Of Left Ventricular Of Obstructive Sleep Apnea Syndrome(OSAS)

Objective: To investigate the influences of obstructive sleep apnea syndrome(OSAS) on diastolic function of left ventricular.Methods: 1 60 patients whose age, BMI, gender ratio were incomparable were divided into two groups according to apnea hypopnea index(AHI): mild-to-moderate OSA group(AHI: 5-30 times/h) and moderate-to-severe OSA group(AHI: 30-40 times/h). 30 cases of health people with matching gender, age and body surface area were selected as the control group(physical examination, outpatient laboratory test, electrocardiogram,and ultrasonic echocardiography). The abnormal group and normal group were given echocardiography and color Doppler ultrasound. 2 Examinations 2.1 Left ventricular end-diastolic diameter(LVDD), left ventricular end systolic diameter(LVSD), left ventricular posterior wall thickness(LPWT) and interventricular septum thickness(IVST) were measured on M-mode image. 2.2 Forward blood flow velocity of mitral valve on color M-mode image was measured while. 2.3 Isovolumic relaxation time(IVRT) was the interval from aortic closure to mitral valve opening. 2.4 Pulse Doppler was used to measure blood flow velocity(E) at early diastolic stage of mitral valve opening and blood flow velocity(A) at late diastolic stage of mitral valve opening, E/A; and tissue Doppler was used to measure blood flow velocity(E′) at early diastolic stage of mitral valve circle and blood flow velocity(A′) at late diastolic stage of mitral valve circle, E′/A′, E/E′,and record pulmonary venous flow spectrum. 3 SPSS 13.0 was used for statistical analysis. Measurement data in accordance with normal distribution were presented as mean ± standard deviation, while measurement data not in accord with normal distribution were presented as median and interquartile range. Since sample size of GD group and normal group were both less than 60, F test was required and significant level was 0.10. Single factor analysis was used to compare normal group, mild-to-moderate OSA group and moderate-to-severe OSA group. LSD, Dunnett and S-N-K inspection was used for paired comparison. P<0.05 refers to statistically significant difference.Results: Comparison between 60 patients with different AHI and 30 healthy people showed:1 Compared to the normal group, LVVD, LVSD, LPWT and IVST of each OSAS group were increased. And the differences among groups were not statistically significant(P>0.05).2 OSAS patients all had prolonged IVRT, decreased E peak, increased A peak, decreased E/A, decreased E′, increased A′and decreased E′/A′, where IVRT、 E′/A′、E/E′were of statistical significance(P<0.05).Conclusion: OSAS can result in the changes of left ventricular structure. OSAS patients had reduced diastolic function of left ventricular.