933-95 Cardiac Hypertrophy in Obstructive Sleep Apnea Syndrome

Abstract

Fifty-one middle-aged male patients with obstructive sleep apnea syndrome (OSAS) were evaluated using two dimensional echocardiography, 24hour blood pressure measurements, polysomnography, and plasma norepinephrine (NE) measurements. Among these patients, left ventricular hypertrophy (LVH) (left ventricular posterior wall thickness (LVPWT) or interventricular septal thickness (IVST) ≥ 12 mm), and right ventricular hypertrophy (RVH) (right ventricular wall thickness (RVT) ≥ 5 mm) were present in 41.2% (21/51) and 11.8% (6/51). LVH was present in 50.0% of group II (apnea index >20) patients and in 30.5% of group I patients (apnea index <20). All patients with LVH had hypertension. RVH was present 21.4% in group II patients and none of the group I patients. IVST, LVPWT, LV mass and obesity index were significantly higher in group II than group I. LV mass was significantly correlated with apnea index, the duration of nocturnal oxygen saturation less than 90%, 24-hour mean blood pressure, weight, BSA, and obesity index. Apnea index, number of apnea, duration of nocturnal oxygen desaturation less than 90%, weight, and obesity index were significantly greater in patients with both LVH and RVH than in patients without LVH or RVH, or those with only LVH. Plasma NE after waking up significantly increased compared with that before sleep (p < 0.05). The ratio of plasma NE levels after waking up to those before sleep was significantly correlated with the duration of nocturnal oxygen desaturation less than 90% (r = 0.83, p < 0.05). but not with apnea index. These results suggest that frequent episodes of oxygen desaturation and/or arousal response caused by apnea may contribute to the complication of LVH and RVH in the long term, and apnea-induced cyclical increase in blood pressure and the resulting sustained elevation in blood pressure associated with the increase in afterload sympathetic activity may playa role in the development of LVH.