Abstract
Purpose :
To evaluate changes in the autonomic nervous system activity associated with the development and severity of retinopathy prematurity
Methods :
Heart rate variability, as an indicator of autonomic nervous system activity, was calculated in two groups of premature infants. The first group was a group of infants that had severe ROP requiring treatments. The second group was a control group of the same age, weight, and similar risk factors, including, same frequency of intraventricular hemorrhage, bronchopulmonary dysplasia, and sepsis. For the purpose of analyzing heart rate variability at different times during their hospital stay, three time points were selected including day 1 of life, day of first ophthalmology evaluation for ROP, and day of ROP treatment or discharge if patient did not receive treatment. The recorded EKG data, sampled at 240 Hz, was exported out of MATLAB and converted to ASCII format compatible with the analysis software package (Kubios HRV). Calculations were done for for the high frequency value (HF m2 ), low frequency value ((HF m2), and low frequency/high frequency value (LF m2/HF m2) of the heart rate variabilty components for all infants in the 2 groups.Trends of changes in the autonomic nervous system activity over time was compared between the two groups using analysis of covariance.
Results :
The 2 groups demonstrated similar increase in the sympathetic activity between birth and the first ophthalmologic examination. Between the first ophthalmologic evaluation and the final evaluation, there was reduction in both the sympathetic and parasympathetic activity, more so for the parasympathetic activity, in the treated group, while in the control group there was increase in both the sympathetic and parasympathetic activity, more so for the parasympathetic activity. The difference in the parasympathetic activity between the two groups was statistically significant (t = 2.9, degree of freedom=12, p=0.01)
Conclusions :
Disruption in the autonomic nervous system activity, particularly the parasympathetic activity, may play an important role in the development and severity of retinopathy of prematurity.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.