8/13/2023 0 Comments Cardiac coherence brainn injuryWe hypothesized that HRV depression would be observed in infants with WS-predominant brain injury compared to infants with normal MRI and that the greatest HRV depression would be observed in infants with a basal ganglia/thalamus (BG)-predominant pattern of injury.īrain injury pattern is associated with reduced HRV at 24 h of life in newborns with HIE who are undergoing therapeutic hypothermia. The aim of this study was to investigate whether HRV is related to the topography of brain injury shown by MRI in newborns with HIE. These findings suggest that autonomic regulation can be mediated by both direct injury to the deep-brain structures including the brainstem as well as to higher-order cortical centers. Recently, we demonstrated that injury at both the cerebral cortical and brain stem levels was associated with ANS dysregulation in newborns with various types of brain injury ( 13). These studies have related HRV metrics to the presence and severity of brain injury, but not to the topography of injury. Prior studies have shown that reduced HRV is associated with severity of brain injury as shown by MRI ( 9), abnormal electroencephalogram findings ( 9, 10), and poor long-term neurodevelopmental outcome ( 10, 11, 12) in infants with moderate to severe encephalopathy. Heart rate variability (HRV) offers a continuous and quantitative method to assess the autonomic nervous system (ANS) non-invasively and has been proposed as a bedside biomarker in newborns with HIE ( 9, 10, 11, 12). Thus, biomarkers that reflect the pattern of brain injury after hypoxia–ischemia that can be measured during hypothermia treatment can provide key information to the bedside clinician that is currently lacking. ![]() Therefore, its use is generally restricted to the subacute period after completion of therapeutic hypothermia when there are fewer factors limiting transport of the critically ill newborn to the scanner. Although MRI provides detailed information on the location of injury, its sensitivity for reflecting the extent of brain injury in the first 24 h of life has been questioned ( 4). Specifically, injury to the basal ganglia and thalamic brain regions has been associated with poor neuromotor outcomes ( 4, 5), whereas cortical watershed (WS)-type injuries relate to school-aged cognitive deficits, particularly lower language-related abilities ( 6). It has been well established that the pattern of injury shown by MRI relates to later developmental outcomes ( 4, 5, 6, 7, 8). Biomarkers that can provide early insights to help specify the type and pattern of brain injury can provide opportunities for targeted therapies and aid in prognostication.Ĭurrently, magnetic resonance imaging (MRI) is the standard for the assessment of brain injury in newborns with HIE ( 2, 3). Although therapeutic hypothermia has improved outcome in infants with moderate and severe encephalopathy, nearly half of these infants continue to have adverse outcomes ( 1). Hypoxic ischemic encephalopathy (HIE) is a major cause of death and disability in newborns. HRV monitoring may provide insights into the pattern of brain injury at the bedside. Conclusionĭegree of HRV depression is related to the pattern of brain injury. Specifically, negative associations were observed between the pattern of brain injury and RMS S (estimate −0.224, SE 0.082, P=0.006), RMS L (estimate −0.189, SE 0.082, P=0.021), and LF power (estimate −0.044, SE 0.016, P=0.006). ![]() ![]() Brain injury pattern was significantly associated with the degree of HRV suppression. Resultsĭata from 74 infants were analyzed. ![]() HRV metrics were compared across brain injury pattern groups using a random-effects mixed model. The brain injury pattern shown by MRI was classified as no injury, pure cortical/white matter injury, mixed watershed/mild basal ganglia injury, predominant basal ganglia or global injury, and death. HRV metrics were quantified in the time domain (α S, α L, and root mean square at short (RMS S) and long (RMS L) timescales) and frequency domain (relative low-(LF) and high-frequency (HF) power) over 24–27 h of life. This study aimed to characterize the relationship between HRV and brain injury pattern using magnetic resonance imaging (MRI) in newborns with HIE undergoing therapeutic hypothermia. Decreased heart rate variability (HRV) is a measure of autonomic dysfunction and brain injury in newborns with hypoxic ischemic encephalopathy (HIE).
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