Graphical Methods for Nonlinear Analysis of ECG Signals

In this paper are presented the current results of scientific research of heart rate variability (HRV) analysis based on digital electrocardiograms (ECG). This analysis is a non-invasive and effective technique to reflect the autonomic nervous system regulation of the heart. HRV is used to diagnose and estimate of alterations in heart rate by measuring the variation of RR intervals (time intervals between two consecutive heart beats). The RR intervals are obtained from 24-hour digital Holter ECG records of healthy and unhealthy subjects. In the presented research work are used two graphical methods for nonlinear analysis of RR time series: Poincaré plot and Rescaled adjusted range Statistics plot (R/S). The obtained results show that these methods are suitable for diagnostic, forecast and prevention of the pathological statuses. Keywords— graphical methods, nonlinear analysis, ECG signal, Poincaré plot, Rescaled adjusted range Statistics plot (R/S), RR interval, Heart Rate Variability (HRV).