To evaluate whether cardiac dysfunction or abnormal measurements on cardiopulmonary exercise testing (CPET) are present in patients with obstructive sleep apnea syndrome (OSAS), and to evaluate what factors are responsible for exercise limitations in these patients.
Two groups of subjects were enrolled. The OSAS group consisted of 20 patients with moderate or severe OSAS. The control group consisted of 20 healthy subjects without OSAS. All subjects underwent spirometric, cardiac evaluation by radionuclide scanning, CPET and an overnight sleep study.
The results showed that there was no difference in left ventricular ejection fraction (VEF) between the OSAS and control groups, but the OSA group had a lower right VEF. Patients in the OSAS group had a lower VO2peak, VO2peak/kg and workpeak than the control group. The OSAS group had a higher breathing reserve and a greater decrease in anaerobic threshold and oxygen pulse.
In conclusion, moderate to severe OSAS patients had abnormal CPET as reflected by low VO2peak/kg, workpeak, anaerobic threshold and oxygen pulse. These abnormalities may have been due to cardiac disease or possible lack of fitness.
In the future, we intend to use cardiopulmonary exercise test to evaluate cardiac function in moderate to severe OSAS patients. OSAS GroupControl GroupRDI, times / hour44.01±8.16*5.14±1.60RVEF, %38.05±4.08*44.20±3.36VO2peak, L/min,1.69±0.21*2.34±0.20
C. Lin, None.