Assessment of Autonomic Dysfunction in Chronic Complete Spinal Cord Injury by Heart Rate Variability

Abstract

Abstract Objectives Non-invasive assessment of cardiac autonomic dysfunction in spinal cord injury (SCI) by means of heart rate variability analysis (HRV). Also, to assess the effect of postural change on neural outflow. Setting Rehabilitation research center, Sawai Man Singh Hospital, Jaipur. Participants 110 patients with SCI were screened, of whom, 12 patients aged between 20 and 30 years with chronic complete SCI and neurological level of T6 or above were included. An equal number of age and sex matched healthy individuals were the controls. Interventions Five minute ECG recording, first in supine position and then in sitting position was done. Outcome measures Frequency domain measures of heart rate variability. Results No significant differences were observed between both the groups in supine rest. On sitting, the absolute power of the low frequency (LF) and high frequency (HF) components were significantly less in the SCI patients than that in the controls. A significantly increased LF-to-HF ratio along with a higher mean heart rate (HR) was observed in the controls on postural change. Conclusion On change of posture, the controls showed a physiologically patterned response, which was not observed in the SCI patients. The loss of this homeostatic mechanism in the SCI subjects was observed, which may reflect a dysfunctional autonomic nervous system interplay in patients with complete SCI.