Assessment of dynamic characteristics of cardiac RR intervals during meditation using Poincaré plot and sequence trend analysis

In this paper, we examine dynamic changes in cardiac inter-beat intervals to explore these differences in cardiac control. Moment-to moment changes in RR intervals during premeditation state were compared with the corresponding values during meditation state. For each state, every RR interval was plotted against the previous interval (Poincar plot) and each change in the inter-beat interval was plotted against the previous change (sequence trend analysis or quadrant analysis plot). The variability in inter-beat intervals is an indicator of the dynamic interaction and the balance between the sympathetic and parasympathetic branches of the autonomic nervous system (ANS). The sympathetic branch decreases the inter-beat intervals, while the parasympathetic branch increases the inter-beat intervals. In this study we evaluated the ANS during two concentration meditation techniques (Kundalini yoga and Chi meditations) using the above two nonlinear methods, namely, Poincar plot and sequence trend analyses. It is found through both the methods that the complex dynamics of the RR interval series is lowered during meditation. Further, during premeditation state there is parasympathetic dominance while during meditation state there is sympathetic dominance, irrespective of the type of meditation. Kundalini yoga group meditators showed higher differences than Chi group meditators.