Left atrial volume Index and circulation time in

obstructive sleep apnea patients

China Medical Uiversity Hospital

Shinn-Jye Laing, Liang- Wen Hang, Kuo-Liang Chiu, Hsin-Yueh Liang, Chih-Pin Chang

Objective: To evaluate the association between the left atrial volume index (LAVi) and apnea-hypopnea index index (AHI) and the circulation time (Ct) in the obstructive sleep apnea (OSA) patients.

Methods:  From January 2007 to January 2008, seventy-five patients referred from cardiologist for polysomnography were retrospectively reviewed. Totally, there were 56 patients enrolled in our series. Demographic characteristics, echocardiograms and polysomnograms were collected and analyzed. The left atrial volume were calculate by using area-length method and LAVi was calculated by the LA volume to body surface area ratio. The circulation time (Ct) was measure the time between the end of obstructive apnea event and peripheral detection of a desaturation pulse by finger oximetry.

Results:  The Student’s test was used to assess the difference between the two groups which divided according to LAVi severity (LAVi > 32 ml/m², and LAVi ≤ 32 ml/m²). On analysis, LAVi was stronger parameter associated with AHI (P value 0.001) than the left ventricular ejection fraction (P = 0.958). Nineteen patients were selected to compare Ct which also divided into two groups according to LAVi; the mean circulation time amounted to 24.82 and to 20.80 seconds, respectively.There was a good positive linear correlation between LAVi and Ct in severe group ( LAVi> 32 ml/m, r=0.9513, P< .0001).

Conclusion:

 LAVi is a significant echocardiographic parameter associated AHI in OSA patient; it also had strong correlation with Ct especially in severer group.