OBJECTIVE: To assess the sympathetic-parasympathetic balance
in individuals with fibromyalgia (FM), and its response to
orthostatic stress, by power spectral analysis of heart rate
METHODS: We studied 19 women with FM and 19 age
matched controls. A high resolution electrocardiogram was
obtained in supine and standing postures after achieving a
stable heart rate. Spectral analysis of R-R intervals was done
by the fast Fourier transform algorithm.
RESULTS: Analyses of
the different frequency components revealed significant
difference between the 2 groups in the low frequency
(0.050-0.150 Hz) band, which reflects modulation of the
sympathetic nervous system. Controls displayed an increased
power spectral density upon standing (+0.081 +/- 0.217 Hz);
individuals with FM had a discordant response (-0.057 +/-
0.097 Hz) (p = 0.018).
CONCLUSION: In FM, there is a deranged
sympathetic response to orthostatic stress. This abnormality
may have implications regarding the pathogenesis of FM.
MCM: Used power-spectral analysis of heart-rate variability
(see for example article UI=97138595). Found that FM pts had
a “deranged sympathetic response to orthostatic stress”