Abstract: Objective To analyze changes in left heart structure and function in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and its correlation with carotid intima-media thickness (CIMT). 
Methods A total of 90 patients with OSAHS were divided into mild group (n=28), moderate group (n=36) and severe group (n=26) according to the apnea hypopnea index. The general data, left ventricular structure and function indexes ［left ventricular end-systolic diameter (LVESD）, left ventricular end-diastolic diameter (LVEDD), left ventricular posterior wall thickness （LVPWT）, interventricular septal thickness （IVST）,left ventricular mass index（LVMI）,left ventricular ejection fractions （LVEF）， eject decel time （EDT）］ and carotid artery function indexes ［pulmonary artery (PA), aortic diameter (AO), dilatancy (DC), compliance (CC), distension (Dis)］ and CIMT were compared among the three groups. The correlation between carotid CIMT and left ventricular structure and function in OSAHS patients was analyzed. 
Results There were no significant differences in sex, age, course of disease, heart rate, diastolic blood pressure and systolic blood pressure among the three groups (P＞0.05). Body mass index (BMI) in moderate and severe groups was higher than that of mild group, and higher in severe group than in moderate group, and the difference was statistically significant (P＜0.05). LVESD, LVEDD, LVPWT, IVST, LVMI, peak A and EDT in moderate and severe group were significantly higher than those in mild group, while LVEF, peak E and E/A were significantly low than those in mild group; LVESD, LVEDD, LVPWT, IVST, LVMI, peak A and EDT in severe group were significantly higher than those in moderate group, while LVEF, peak E and E/A were significantly lower than those in moderate group (P＜0.05). PA, AO, DC, CC, Dis and IMT in moderate and severe group were significantly higher than those in mild group, and PA, AO, DC, CC, Dis and CIMT in severe group were significantly high than those in mild group (P＜0.05). The carotid CIMT was positively correlated with left ventricular structure and function indexes LVESD, LVEDD, LVPWT, IVST and LVMI respectively (r=0.334, 0.318, 0.416, 0.316, 0.438, P＜0.05), and negatively correlated with LVEF (r=-0.356, P＜0.05). 
Conclusion The left heart structure and function and carotid CIMT of OSAHS patients will change obviously with the aggravation of the disease, and there is a significant correlation between them, which can provide evidence for the prevention and treatment of cardiovascular diseases in OSAHS patients.

Key words: sleep apnea, obstructive, carotid intima-media thickness, ventricular function, left