Power spectral analysis of heart rate variability of myocardial infarcted patients (non-invasive method)

In the present work surface electrocardiogram in lead II configuration has been chosen as the sample data as it has distinguished features for the accurate detection of the R-points for HRV analysis. The data used in the study is from ten normal patients for the duration of 8 minutes, at a sampling frequency of 500 Hz, using the DAS together with A/D converter, interfaced to a computer. The data for ten MI patients are selected from the European ST database. A high precision algorithm has been developed and implemented in MATLAB platform for the accurate detection of R-points. The conversion of these randomly occurring point processes into uniformly sampled signal is done by backward step interpolation technique. The sampled HRV signal is filtered by band pass filters at the LF (0.05 Hz - 0.15 Hz) and HF (0.15 Hz - 0.4 Hz) bands. The power spectrum of both bands of HRV signal has been estimated using FFT. The total power ratio and the peak power ratio of LF to HF band calculated for MI patients showed a drastic increase when compared to normal subjects. Also the total power in Ml patients has shown a drastic reduction