Analysis of lagged Poincare plots in heart rate signals of women referred to meditation clinic

Poincare plots are commonly used to study nonlinear behaviour of physiologic signals. Analysis of Poincare plots for various lags can provide interesting insights into the autonomic control of the heart. Furthermore, the width of Poincare plots can be considered as a criterion of short-term variability in heart rate signals. The hypothesis that Poincare plot indexes of heart rate variability (HRV) detect dynamic changes during meditation over the HRV in healthy women was examined. Poincare plots with six different lags (1-6) were constructed for two sets of data and the width of the Poincare plot for each lag was calculated. The results show that during meditation the width of Poincare plot tended to increase as the lag increased. During meditation, the width of Poincare plot with lag-1 was 2.5±0.88 and with lag-6 was 4.77±2.5. The Poincare plot is a quantitative visual tool which can be applied to the analysis of R-R interval data gathered over relatively short time periods. The simplicity of the width of Poincare plot calculation and its' adaptation to the chaotic nature of the biological signals could be useful to evaluate heart rate signals during meditation. Keywords— Heart Rate Variability, Lagged Poincare Plots, Meditation, Nonlinear Dynamics.