A non-linear analysis of Heart Rate Variability in stroke patients

摘要

The analysis of heart rate variability is a well recognized non-invasive tool to investigate the cardiovascular autonomic control but only limited data are available on the autonomic imbalance assessment of stroke patients by heart rate variability changes after a prior single stroke, using time- and frequency-domain linear methods. To evaluate the relationship between lesion's severity and PPlots features, 20 first-ever stroke subjects, divided for a single or multiple medium cerebral artery lesion, and 10 healthy subjects were studied. All underwent to a 24-hour ECG recording analysed by PPlots, spectral and time-domain techniques. PPlots were quantified by computer-generated indexes, namely the length (L), wideness (W) and area (A) of 2D plots and the number of peaks (Np) and the length of the radii of inertia (Px,y,z) of the 3D plots. Power spectral density was estimated on 5 minutes sequences by the Blackman-Tukey method in the VLF, LF and HF band by numerical integration. SDNN, PNN50, MSSD time-domain parameters were also evaluated. Statistical analyses were performed by the Kruskal-Wallis and Dunn's post hoc test for multiple comparisons. A direct relationship between increasing lesion's severity and progressive collapsing of both 2D and 3D Pplots was observed. L, A and Np, showed the highest significant differences between all groups, while lower significance was found for spectral and time-domain parameters. These data suggest that PPlots analysis contains relevant information related to different HRV dynamics in normal and stroke subjects with different lesion's severity.