Recurrence Quantification Analysis of heart rate and blood pressure variability in obese children and adolescents

Obesity is a rapidly growing complex medical problem and increasingly occurs already in childhood. The change in the autonomic nervous system activity is an important factor contributing to initiation and progression of various cardiovascular complications of obesity. The aim of this study was to detect the presence of cardiovascular dysregulation using novel nonlinear measures and compare their performance with linear heart rate and blood pressure variability (HRV and BPV) analysis. We examined 40 obese children and adolescents (age 14.2 [13.1 -16.1] (median [interquartile range]) years) and 40 age and gender matched control subjects. Continuous finger arterial blood pressure (FinometerPro, FMS, Netherlands) and ECG signal recorded from bipolar thoracic lead (Cardiofax ECG-9620, NihonKohden, Japan) were measured in supine position. HRV and BPV time series (2000 heart beats length) were analysed using linear analysis and using nonlinear recurrence quantification analysis (RQA). Only RQA measures in HRV analysis were able to detect a reduction in cardiovascular control complexity associated with obesity. We conclude that RQA is a sensitive method to detect subtle abnormalities in heart rate dynamics associated with obesity.