Complexity analysis of heart rate variability applied to chagasic patients and normal subjects

Different techniques of non-linear dynamics analysis have been used to study the heart rate variability HRV, in chagasic patients and in healthy subjects. RR intervals were obtained from high-resolution ECG. A control group (n=18) and three groups of chagasic patients, group Ia (n=14), group Ib (n=16) and group II (n=15) were considered for the analysis. Some complexity measures based on symbolic dynamics and Shannon entropy were applied in order to characterize the different groups. Applying the U of the Mann-Whitney test, significant differences were obtained with the complexity measures when all groups were compared (p<0.05). It can be concluded that these methods are able to extract the essential information of non-linear features of the heart rate dynamics, and provide promising complexity measures which could be used to classify, and differentiate chagasic patients