The use of short-term analysis of heart rate variability to assess autonomic function in obese children and its relationship with metabolic syndrome

Background: The cardiovascular autonomic nervous system in obese children is one of the main initiators of coronary heart disease and hypertension and may have a close relationship with insulin resistance. Heart rate variability is one non-invasive method to assess the cardiovascular autonomic system. In this method, low frequency parameters reflect sympathovagal activity, high frequency parameters reflect vagal activity and the ratio of these parameters reflects sympathovagal balance. Methods: In this study, a short-term analysis of heart rate variability was conducted in 66 obese children and 40 healthy controls. Results: While high frequency parameter values are lower in the obese group compared to the controls (16.02 +/- 12.9 nu vs. 21.45 +/- 13.6 nu, p = 0.046), the low frequency/high frequency ratio is found significantly higher (3.79 +/- 2.34 vs. 2.25 +/- 0.93, p < 0.001). A significant difference was not detected for the low frequency values (p = 0.787). Insulin resistance was found in 33(50%) patients, dyslipidemia was found in 39(59%) and hypertension was found in 18 (27%). Metabolic syndrome was detected in 39% patients in the obese group. Conclusions: We found that vagal activity was decreased in the obese group and the autonomic nervous system balance was impaired in favor of sympathetic activity in the short-term heart rate analysis. (Cardiol J 2012; 19,5: 501-506)