A Systematic Review of the Relationship Between Traumatic Brain Injury and Disruptions in Heart Rate Variability

Area of Science:

• Neurology
• Cardiology
• Physiology

Background:

• Autonomic nervous system (ANS) dysfunction is a frequent complication following traumatic brain injury (TBI).
• Heart rate variability (HRV), a measure of beat-to-beat heart rate changes, reflects ANS function and is impacted by TBI.
• Understanding HRV changes post-TBI is crucial for assessing outcomes and recovery.

Approach:

• This systematic review followed PRISMA guidelines to analyze the existing literature on HRV dysfunction after TBI.
• Eighty-nine studies were included, with data coded and quality assessed by two independent raters.
• The review aimed to determine the prevalence of HRV dysfunction, its association with TBI severity, and its predictive value for mortality and recovery.

Key Points:

• TBI, regardless of severity, is consistently associated with diminished HRV.
• The degree of TBI severity influences the relationship between HRV and patient recovery.
• Reduced HRV following TBI is a predictor of mortality, independent of age.
• HRV disturbances can persist even after symptom resolution and return-to-play in mild TBI cases.

Conclusions:

• Current evidence strongly suggests that TBI leads to decreased HRV.
• HRV serves as a valuable indicator of physiological changes post-TBI.
• Diminished HRV is a significant predictor of critical outcomes, including mortality and symptom improvement following TBI.