Does traumatic quadriplegia alter the power spectral components of heart rate variability compared to healthy controls?
The disappearance of the low-frequency component of heart rate variability in quadriplegic patients suggests that cervical spinal sympathetic pathways are instrumental in generating this component in humans.
This study investigated the spontaneous beat-to-beat variabilities in R-R intervals of six traumatic neurologically complete quadriplegic (QP) males and six age-matched healthy males (control) while they were at rest in the supine position in a climatic chamber (temperature 30 degrees C, relative humidity 60%) by means of autoregressive power spectral analysis. As shown by earlier studies, in the control group there were two major spectral components, a high-frequency (HF) component center frequency 0.30 +/- 0.02 (SE) Hertz equivalent (Hz eq), power 767.5 +/- 384.6 ms2 and a low-frequency (LF) component (0.11 +/- 0.01 Hz eq, 707.5 +/- 198.8 ms2). On the contrary, in the QP group, only the HF component was observed (0.30 +/- 0.02 Hz eq, 421.8 +/- 134.7 ms2). The results suggest that 1) the disappearance of the LF component in the QP subject is presumably caused by the interruption of the spinal pathways linking supraspinal cardiovascular centers with the peripheral sympathetic outflow, and 2) the cervical spinal sympathetic pathways may be instrumental in the genesis of the LF component in humans.
Inoue et al. (Fri,) studied this question.