Abstract
We analyze the dynamic quality of the R– R interbeat intervals of electrocardiographic signals from healthy people and from patients with premature ventricular contractions (PVCs) by applying different measure algorithms to standardised public domain data sets of heart rate variability. Our aim is to assess the utility of these algorithms for the above mentioned purposes. Long and short time series, 24 and 0.50 h respectively, of interbeat intervals of healthy and PVC subjects were compared with the aim of developing a fast method to investigate their temporal organization. Two different methods were used: power spectral analysis and the integral correlation method. Power spectral analysis has proven to be a powerful tool for detecting long-range correlations. If it is applied in a short time series, power spectra of healthy and PVC subjects show a similar behavior, which disqualifies power spectral analysis as a fast method to distinguish healthy from PVC subjects. The integral correlation method allows us to study the fractal properties of interbeat intervals of electrocardiographic signals. The cardiac activity of healthy and PVC people stems from dynamics of chaotic nature characterized by correlation dimensions d f equal to 3.40±0.50 and 5.00±0.80 for healthy and PVC subjects respectively. The methodology presented in this article bridges the gap between theoretical and experimental studies of non-linear phenomena. From our results we conclude that the minimum number of coupled differential equations to describe cardiac activity must be six and seven for healthy and PVC individuals respectively. From the present analysis we conclude that the correlation integral method is particularly suitable, in comparison with the power spectral analysis, for the early detection of arrhythmias on short time (0.5 h) series.
Highlights
Sudden cardiac death remains one of the continuing challenges to the modern clinician
Peng et al [9,10] studied the scale behavior of heartbeat series using a power spectral method and showed that healthy and ill people present different power behavior. We have applied this method to Premature ventricular contractions (PVCs) subjects and found that they cannot be distinguished from healthy people
To summarize we compare two different methods to study the dynamics of the cardiac rhythms of healthy and PVC people: the power spectral analysis and the correlation integral method
Summary
Sudden cardiac death remains one of the continuing challenges to the modern clinician. Peng et al [9,10] studied the scale behavior of heartbeat series using a power spectral method and showed that healthy and ill people present different power behavior We have applied this method to PVC subjects and found that they cannot be distinguished from healthy people. To summarize we compare two different methods to study the dynamics of the cardiac rhythms of healthy and PVC people: the power spectral analysis and the correlation integral method. Analyses were made over the time series of R–R interbeat intervals, using series of almost 30 min By comparing both methods we conclude that the correlation integral method is more adequate than the power spectral analysis to provide clues to distinguish between healthy and PVC subjects.
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