Analysis of lagged Poincare plots in heart rate signals during meditation

In heart rate analysis, the width of Poincare plots can be considered as a criterion of short-term variability in signals. The aim of this study is to evaluate the effect of different lags on the width of the Poincare plots in heart rate signals during meditation. For this purpose, we used heart rate signals available in Physionet database. 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 2.2 +/- 0.6 and with lag-6 was 7.3 +/- 1.7. 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. (C) 2010 Elsevier Inc. All rights reserved.