Some characteristics of low-amplitude cardiac signals

We present the results of an experimental study of the low-amplitude cardiac signals without temporal and spatial averaging. The characteristics of the fluctuation and quasi-periodic components of the low-amplitude signals are determined statistically reliably for the first time. The results of the studies of the periodic and quasi-periodic components obtained from the long-term measurement data are reported. It is found that the structure of the frequency characteristics of low-amplitude signals has pronounced temporal variability in the neighboring cardiac cycles.