In infants with congenital heart disease autonomic dysfunction is associated with pre-operative brain injury.

Abstract

Background:Brain injury is a serious and common complication of critical congenital heart disease (CHD). Impaired autonomic development (assessed by heart rate variability; HRV) is associated with brain injury in other high-risk neonatal populations.Objective:To determine whether impaired early neonatal HRV is associated with pre-operative brain injury in CHD.Methods:In infants with critical CHD, we evaluated HRV during the first 24 hours of cardiac ICU (CICU) admission using time-domain (RMS1, RMS2, and alpha 1) and frequency-domain metrics (LF, nLF, HF, nHF). Pre-operative brain MRI was scored for injury using an established system. Spearman’s correlation coefficient was used to determine the association between HRV and pre-operative brain injury.Results:We enrolled 34 infants with median birth gestational age (GA) of 38.8 weeks (IQR 38.1-39.1). Median postnatal age (PNA) at pre-operative brain MRI was 2 days (IQR 1-3 days). Thirteen infants had MRI evidence of brain injury. RMS 1 and RMS 2 were inversely correlated with pre-operative brain injury.Conclusions:Time-domain metrics of autonomic function measured within the first 24 hours of admission to the CICU are associated with pre-operative brain injury, and may perform better than frequency domain metrics under non-stationary conditions such as critical illness.