Nonlinearity parameters for the classification of high risk myocardial infarction subjects

The paper presents the analysis of the Heart Rate Variability (HRV) signal in 19 subjects who recently had a Myocardial Infarction episode (MI). The study follows a nonlinear approach based on the multiparametric analysis of some invariant properties of the dynamical system generating the time series. First the authors reconstruct the system embedding space from the HRV time series. The False Nearest Neighbors (FNN) criterion provides the real embedding dimension value. Results show that through the FNN method it is possible to identify the correct number of LE in the system. Parameter values significantly separate subjects who after MI keep a good performance of the cardiac pump (normal ventricular ejection function, NEF) vs. the group which after MI shows a reduced ventricular ejection fraction (REF)