Assessment of cardiovascular autonomic function in patients with spinal cord injury submitted to heart rate variability

Abstract

The objective was to assess the effects of cardiovascular autonomic nervous system through the heart rate variability (HRV) in subject with complete spinal cord injury (SCI) at different levels. 32 subjects participated in the study, divided into three groups: 13 tetraplegic patients (G1), 8 paraplegic patients (G2) and 11 healthy subjects formed the control group (CG). All underwent the assessment HRV, made from data obtained by record of 15 minutes, generated by the cardiac monitor, connected to a laptop, wich recorded on recording on-line RR intervals. The HR at rest in the supine position was lower in G1 compared to G2 and CG. HRV was highest in G1 in the supine position. HRV was lower in the standing position in the G1 compared to G2 and CG, as a consequence of the greater decrease in BP. Spectral analysis showed a reduction in G1 and GC of high-frequency power (decrease in vagal activity) and increased the ratio B / A represents the intensity decreased vagal tone in G1 and increased adrenergic activity in GC. The results showed an autonomic dysfunction in tetraplegics and paraplegics equivalent results in the control group.