Significance and usefulness of heart rate variability in patients with multiple system atrophy

Background: The purpose of this study was to investigate whether heart rate variability parameters can be useful for evaluating cardiac autonomic dysfunction in multiple system atrophy patients. Methods: Both the time and frequency domains of heart rate variability were investigated among 17 multiple system atrophy patients and 27 normal control subjects. Results: All time-and frequency-domain measures, except the low-to high-frequency ratio, were significantly lower in multiple system atrophy patients than in controls. In multiple system atrophy patients, there were significant inverse correlations between heart rate variability parameters and disease duration, as well as disease severity, but heart rate variability parameters were not affected by other autonomic dysfunctions. Conclusions: The cardiac autonomic state of multiple system atrophy was characterized by decreases in both sympathetic and parasympathetic tones. Because heart rate variability parameters were not affected by other autonomic dysfunctions, this may be a useful method for evaluating cardiac autonomic dysfunction in multiple system atrophy. (C) 2012 Movement Disorder Society