Obstructive sleep apnea (OSA) and left ventricular (LV) hypertrophy are considered to be closely associated. However, the relationship has not yet been fully demonstrated and is hence still controversial. The purpose of this study was to assess in hypertensive male patients the relationship between OSA and cardiac structure using a new index, namely, integrated area of desaturation (IAD), in addition to the apnea-hypopnea index (AHI) that is currently the most frequently used index of sleep-disordered breathing.METHODS
In our cross-sectional study, 223 hypertensive men younger than 65 years with sleep apnea and normal cardiac function were enrolled. All subjects were evaluated by fully attended polysomnography. Cardiac structure and function were evaluated by echocardiography.RESULTS
LV mass index significantly correlated with IAD (r = 0.203, P < 0.05), but not with AHI. Multivariate linear regression analyses showed that IAD, brain natriuretic peptide (BNP), and age are independent variables affecting the LV mass index (β = 0.262, 0.237, and 0.173, respectively, P < 0.05). IAD was the one and only determinant among the indices of sleep-disordered breathing.CONCLUSIONS
Nocturnal intermittent hypoxia defined by IAD may be associated with LV hypertrophy in men with well-controlled hypertension and obstructive sleep apnea.