Trajectories of parasympathetic nervous system function before, during, and after feeding in infants with transposition of the great arteries

Abstract

Background: Compromised parasympathetic response to stressors may underlie feeding difficulties in infants with complex congenital heart defects, but little is known about the temporal pattern of parasympathetic response across phases of feeding.

Objectives: The aim of this study was to describe initial data exploration of trajectories of parasympathetic response to feeding in 15 infants with surgically corrected transposition of the great arteries and to explore the effects of feeding method, feeding skill, and maternal sensitivity on trajectories.

Method: In this descriptive, exploratory study, parasympathetic function was measured using high-frequency heart rate variability (HF HRV), feeding skill was measured using the Early Feeding Skills assessment, and maternal sensitivity was measured using the Parent-Child Early Relational Assessment. Data were collected before, during, and after feeding at 2 weeks and 2 months of age. Trajectories of parasympathetic function and relationships with possible contributing factors were examined graphically.

Results: Marked between-infant variability in HF HRV across phases of feeding was apparent at both ages, although it was attenuated at 2 months. Four patterns of HF HRV trajectories across phases of feeding were identified and associated with feeding method, feeding skill, and maternal sensitivity. Developmental increases in HF HRV were apparent in most breast-fed, but not bottle-fed, infants.

Discussion: This exploratory data analysis provides critical information in preparation for a larger study in which varying trajectories and potential contributing factors can be modeled in relationship to infant outcomes. Findings support inclusion of feeding method, feeding skill, and maternal sensitivity in modeling parasympathetic function across feeding.

Figures

Figure 1

Example of high frequency heart rate variability (HF HRV) measure in one infant across three phases of feeding by 5-minute epoch (solid line) and phase average (dashed line). During-feeding phase is shaded.

Figure 2

Data collection protocol. High frequency heart rate variability (HF HRV) measured pre-, during, and postfeeding. Maternal sensitivity, attunement, and warmth (MSAW) measured using one videotaped feeding at each age. Feeding skill measured in real time during feeding.

Figure 3

Individual trajectories of high frequency heart rate variability (HF HRV) by phase averages at 2 weeks and 2 months of age. Arrows identify Infant 12 trajectories at 2 weeks and 2 months, illustrating one infant’s change over time.

Figure 4

High frequency heart rate variability (HF HRV) by phase averages. Infants with feeding skill less than the group median are depicted in dashed lines at 2 weeks (A) and 2 months (B). Infants whose mothers’ maternal sensitivity, attunement, and warmth (MSAW) scores were less than 4 are depicted in dashed lines at 2 weeks (C) and 2 months (D).

Figure 5

Relationships among feeding method; feeding skill; maternal sensitivity, attunement, and warmth (MSAW); and high frequency heart rate variability (HF HRV) at 2 weeks of age. One infant receiving exclusive nasogastric feedings at this age is not shown. (A) depicts feeding skill by maternal sensitivity for each infant. Breastfed infants are identified with triangles; bottle-fed infants with dots. Area of graph encompassing feeding skill below the median and maternal sensitivity, attunement, and warmth (MSAW) scores less than 4 is enclosed with dotted lines. Squared dot identifies one infant with less feeding skill and high MSAW scores. Circled dots identify two infants with less feeding skill and low MSAW scores. Arrows are drawn to these infants’ high frequency heart rate variability trajectories in (B). (B) depicts high frequency heart rate variability by feeding phase. Breastfed infants are identified with dashed lines; bottle-fed infants with solid lines.

Figure 6

Relationships among feeding method; feeding skill; maternal sensitivity, attunement, and warmth (MSAW); and high frequency heart rate variability (HF HRV) at 2 months of age. (A) depicts feeding skill by maternal sensitivity for each infant. Breastfed infants are identified with triangles; bottle fed infants with dots. Area of graph encompassing feeding skill below the median and maternal sensitivity, attunement, and warmth (MSAW) scores less than 4 is enclosed with dotted lines. Squared dot identifies one infant with less feeding skill and high MSAW score. Circled dot identifies one infant with less feeding skill and low MSAW score. Arrows are drawn to these infants’ high frequency heart rate variability trajectories in (B). (B) depicts high frequency heart rate variability by feeding phase. Breastfed infants are identified with dashed lines; bottle-fed infants with solid lines.

Figure 7

Quadratic regression lines fit to 5-minute epochs of high frequency heart rate variability (HF HRV) across feeding in breastfed infants at 2 weeks and 2 months of age. During-feeding phase is shaded.

Figure 8

Quadratic regression lines fit to five minute epochs of high frequency heart rate variability (HF HRV) across feeding in bottle fed infants at 2 weeks and 2 months of age. During-feeding phase is shaded. Two bottle-fed infants are not depicted: one was exclusively nasogastric tube fed at 2 weeks and one was missing during feeding data at 2 months due to equipment failure.

Figure 8

Quadratic regression lines fit to five minute epochs of high frequency heart rate variability (HF HRV) across feeding in bottle fed infants at 2 weeks and 2 months of age. During-feeding phase is shaded. Two bottle-fed infants are not depicted: one was exclusively nasogastric tube fed at 2 weeks and one was missing during feeding data at 2 months due to equipment failure.