Exploring factors associated with heart rate variability in newly injured traumatic cervical spinal cord injury patients

Abstract

Background: Assessment of heart rate variability (HRV) in traumatic cervical spinal cord injury (SCI) patients is widely reported, but few studies have examined the HRV in the newly injured. Further, there is paucity of data relating HRV to factors that might have a bearing on the extent of variability in them. Aim and Objectives: The current study explored the factors associated with the HRV of newly injured cervical SCI American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade A/B patients. Materials and Methods: A secondary analysis of HRV data acquired from 24 newly injured tetraplegic patients in a previously published study compared the HRV between AIS grade A and B patients, and across cervical levels of lesion. In addition, the correlation of HRV indices with duration since injury and the patients’ age was examined. Results: The ratio of low to high frequency power was significantly lower in AIS B compared to AIS A patients, and significantly negatively correlated with duration since injury. Conclusion: The ratio of modulations of cardiac sympatho-vagal supply was lower in AIS B patients and reduced with increasing duration since injury. AIS grade and duration since injury need to be considered when interpreting the HRV data of newly injured tetraplegic patients.