Nonlinear analysis of the heart rate variability

The heart rate variability of RR (or HRV) beat by beat of ECG signal is of major clinical importance for the follow-up of a certain number of pathologies, in particular the disorders of the ventricular rhythm which is generally responsible for sudden death. We analyzed the heart rate variability by means of nonlinear methods: Poincaré plot, which is a scattergram, constructed by plotting RR interval against the previous one. The poincaré plot (PP) is one of the many techniques used for ascertaining the heart rate variability, which in turn is maker of the activity of the autonomic system.