Altay Sahin | PubMed Health

PubMed2006

Increased myocardial vulnerability and autonomic nervous system imbalance in obstructive sleep apnea syndrome.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is characterized by the repeated episodes of upper airway obstruction during sleep, leading to significant hypoxia. Noninvasive evaluation of autonomic nervous system (ANS) and myocardial vulnerability may help determination of OSAS patients who are under high risk of malignant cardiac arrhythmias. The aim of this study was to show the effects of OSAS on predictors of arrhythmias by the evaluation of heart rate turbulence (HRT), heart rate variability (HRV) and QT dynamicity reflecting the ANS balance and myocardial vulnerability. METHODS: After polysomnographic study, 80 patients with OSAS and 55 age matched OSAS (-) subjects were included in the study. Twenty-four-hour Holter monitoring was performed in all subjects. HRT, HRV and QT dynamicity parameters were calculated. RESULTS: Turbulence slope was significantly decreased in OSAS patients whereas turbulence onset was increased (P<0.001). QT/RR slopes were significantly increased for QT end and QT apex (P<0.001). In HRV analysis, autonomic balance changed in favor of sympathetic system at night in OSAS patients. Furthermore, HRT and QT dynamicity parameters are found to be correlated with Apnea-Hypopnea Index (AHI). CONCLUSION: OSAS is associated with a significant worsening in HRV, HRT, and QT dynamicity parameters. Our results may indicate that HRV and QT dynamicity parameters can be useful noninvasive methods that may detect autonomic nervous system activity and ventricular vulnerability in OSAS.

Aged↗

PubMed2005

Body fat composition: a predictive factor for obstructive sleep apnea.

OBJECTIVE: To investigate body fat composition, measured by bioelectrical impedance assay (BIA), for predicting the presence and severity of obstructive sleep apnea-hypopnea syndrome (OSAHS). Body fat composition was also compared with other well-known OSAHS predictors such as body mass index (BMI), neck circumference, and abdominal visceral fat. STUDY DESIGN: A prospective study was designed. Fifty-one patients (41 male, 10 female), who were referred to Hacettepe University Faculty of Medicine, Department of Otorhinolaryngology, Head and Neck Surgery with suspected OSAHS, between April 2003 and June 2004, were included in the study. METHODS: All patients underwent polysomnography (PSG) and were classified according to their apnea-hypopnea index (AHI) into four groups. The cross-sectional area of abdominal visceral fat was measured by computed tomography (CT) scanning in 33 of the patients. Neck circumference and BMI was measured for all patients. BIA was performed to determine body fat composition. The groups were compared, and correlation of the variables with AHI was investigated. RESULTS: Of the variables, BMI and percentage of body fat (determined by BIA) were found to be significantly correlated with AHI (r = 0.782, r = 0.647). CT of cross-sectional area of abdominal visceral fat provided 100% sensitivity and specificity (P < .001) in differentiating simple snorers from OSAHS patients. By combining percentage of body fat and body fat mass, higher levels of sensitivity (95%) and specificity (100%) were achieved for diagnosis of OSAHS. CONCLUSION: It was concluded that the BIA could be an inexpensive and practical alternative to prePSG screening tests and should be included in the evaluation of OSAHS patients.

Adult↗