Session P81.7

Modifications in the Heart Dynamics of Patients with Cardiac Disease

FMHS Pereira da Silva*, AC Silva Filho, OF Souza, L Gallo Jr

University of São Paulo
Ribeirão Preto, Brazil

Carriers of many cardiac diseases can suffer cardiac damage and can exhibit cardiac arrhythmia, which is a general denomination for many disturbances that modify the cardiac rhythm. 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. More specifically, from 12 healthy individuals and 16 with cardiac disease, at many scattered ages, all of them at rest. 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. This way was chosen since the dynamics of the cardiac system is chaotic and complex and, therefore, demands more sophisticated mathematical tools. The parameter chosen here is the Correlation Dimension, because it can be interpreted as an indicator of the number of degrees of freedom and, consequently, 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 men with cardiac disease (with p <0.01 in a Mann-Whitney non parametric test).

(Abstract Control Number: 175)