Spectral Bands Analysis of ECG Derived Signals in Chagasic Patients
The aim of this work was to evaluate interactions between spectral bands in five time series (TS) signals from five ECG derived measures. These TS were calculated from 11 healthy subjects and 53 chronic Chagasic patients using high resolution electrocardiography (HRECG). Chagasic patients were classified in two groups (I and II) according to their cardiac damage. For each heartbeat, the cardiac vector magni-tud (CVM) was built and the TS were derived from the follow-ing measures: a) QRSonR, the interval duration from the beginning of the CVM to its peak, b) RQRSoff, the interval duration from the peak of CVM to its ending, c) QRSd, the width of the CVM, d) RpAmp, the max amplitude of CVM and e) RR, the interval between two consecutive heartbeats. The TS derived from the first three measures were correlated with the TS from the last two in the High Frequency (HF) [0.15-0.4 Hz], Low Frequency (LF) [0.04-0.15 Hz] and Very Low Fre-quency (VLF) [<0.04 Hz] spectral bands. It has been found that correlation between TS from RR and QRSd in the VLF band was significantly different (p<0.05) between healthy subjects against groups I and II. We conclude that beat-to-beat analysis of HRECG records is a promising technique for the cardiac assessment of chagasic individuals.
KeywordsChagas disease HRECG spectral analysis
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