Heart rate variability study in ambulatory stroke survivors

To compare the parasympathetic activity of stroke survivors with that of normal subjects, power spectral analysis of heart rate variability (HRV) was performed on 6 pairs of age and gender matched stroke survivors and normal subjects. Four minutes of EKG data were collected from the subjects during sitting, supine, paced breathing and exercising using a Holter monitor. For each subject, parasympathetic activity was measured by calculating the area under the peak at the respiration frequency (0.15 to 0.4 Hz) in the power spectrum of the HRV. The power spectral analysis of HRV from the stroke survivors revealed significantly less parasympathetic activity than in normal subjects.