The analysis of FHR parameters, approximate entropy and canonical correlation of fetuses with mild baseline tachycardia

Hwang, Jung Hye; Yoon, Sang Soon; Moon, Hyung; Park, Young Sun; Cha, Kyung Joon; Park, Moon Il

Abstract

OBJECTIVE
This study was to determine differences of fetal heart rate (FHR) parameters, approximate entropy, canonical correlation coefficient and perinatal outcome between fetuses with mild baseline tachycardia (FHR range : 161-180 bpm) and fetuses with normal baseline FHR.
METHODS
Using our own software developed by Hanyang University Hospital in Korea, non-stress tests were performed for 20 minutes and cases were divided into two groups; mild tachycardia group (FHR range ; 161-180 bpm, 100 cases) and normal group (FHR ranges ; 120-160 bpm, 197 cases). And then, we analyzed various FHR parameters, approximate entropy, adjusted canonical correlation coefficient and perinatal outcome in each group.
RESULTS
Perinatal outcomes between two groups were not significant. However, mean minute range (MMR) was lower and the number of deceleration (15 bpm for 15 sec, more than one) was significantly higher in fetuses with mild tachycardia than normal group (p<0.05). The apprximate entropy and canonical correlation coefficient showed respectively 0.77+/-0.02, 0.45+/-0.06 in mild tachycardia group and 0.80+/-0.01, 0.43+/-0.07 in normal group, there were no significant differences.
CONCLUSIONS
The results showed that mild baseline tachycardia in this range were not associated with an increase in the incidence of adverse perinatal outcome, although decreased MMR and increased number of deceleration in mild tachycardia group may suggest hidden subtle change of FHR parameters. Fetuses with mild tachycardia were not different irregularity of FHR quantified by approximate entropy from normal fetuses and were also similar tendency to correlation with perinatal outcome by adjusted canonical correlation coefficient, which is a multivariate extension of the univariate correlation analysis.