Modifications in the heart dynamics of patients with cardiac disease

摘要

We know, nowadays, that the dynamics of cardio respiratory system is extremely complex and chaotic. Any modification in the systems dynamics can be a sign of a disease. This work investigates the presence of modifications in the dynamics of the cardiac rhythms through the observations in the dynamics of the attractor built from RR series. For each series, the decorrelation time was measured in order to obtain the delay time and, then, to reconstruct the attractor. In order to estimate nonlinear parameters, the existence or not of stationarity was investigated through tests that utilize the surrogate procedure. The parameter chosen here is the Correlation Dimension, because it can be interpreted as an indicator of the degree of system's organization. In this way, the more complex is a system, the greater is its Correlation Dimension. That was exactly what we got: the correlation dimension is significantly smaller in the group of man with cardiac disease.