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Updated: Jun 21, 2026
Measuring Cardiac Autonomic Nervous System (ANS) Activity in Children
Published on: April 29, 2013
Circadian cardiac autonomic function in perinatally HIV-infected preschool children
1Serviço de Cardiologia, Universidade do Estado do Rio de Janeiro, Serviço de Cardiologia, Corpo de Bombeiros Militar do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil. ecgar@yahoo.com
Insights
Autonomic dysfunction in preschool children with perinatal HIV infection is linked to lower CD4+ counts. Impaired heart rate variability (HRV) and QT interval adaptation suggest parasympathetic nervous system dysfunction correlating with immune status.
Area of Science:
- Cardiology
- Infectious Diseases
- Pediatrics
- Autonomic Neuroscience
Background:
- Perinatally HIV-infected (PHIV) children face risks of cardiovascular complications and autonomic dysfunction.
- Early assessment of autonomic function is crucial for managing PHIV children.
- Immune status, indicated by CD4+ T-cell counts, is a key factor in disease progression.
Purpose of the Study:
- To investigate heart rate variability (HRV) and QT interval adaptation in preschool children with PHIV.
- To assess autonomic function in relation to immunological status (CD4+ counts).
- To evaluate early-stage autonomic dysfunction in PHIV children with preserved cardiac function.
Main Methods:
- Enrolled 35 clinically stable, perinatally HIV-infected preschool children.
- Classified children into three groups based on CD4+ counts (<500, 500-999, ≥1000 cells/µL).
- Measured 24-hour heart rate variability (RRV) indexes (NN, SDANN, SDNN index, r-MSSD) and QT/QTc intervals.
- Analyzed nocturnal and daytime segments, comparing groups using correlation and ANOVA.
Main Results:
- CD4+ count positively correlated with NN interval (r=0.45, P=0.003).
- Group 3 (CD4+ <500) showed significantly lower nighttime SDNN index, r-MSSD, and overall NN, SDNN index, and r-MSSD compared to other groups.
- Impaired nocturnal QT interval adaptation was observed across all groups.
Conclusions:
- Parasympathetic-mediated autonomic dysfunction in PHIV children parallels their immune status.
- Reduced HRV and impaired circadian QT interval adaptation are evident even in early stages of HIV infection.
- These findings highlight the need for monitoring autonomic function in PHIV children.
Abstract:
The 24-h heart rate variability and QT-interval adaptation was investigated in perinatally HIV-infected preschool children classified according to immunological status in order to assess autonomic function at early stages of infection. Thirty-five perinatally HIV-infected and clinically stable children (4.8 +/- 0.3 years) were enrolled after approval of the study by the University Hospital Pedro Ernesto Ethics Committee and written informed parental consent was obtained. The children were classified according to peripheral CD4+ count (cells/microL) as follows: group 1, N = 11 (>or=1000); group 2, N = 7 (>or=500 and <1000); group 3, N = 17 (<500). Left ventricular ejection fraction (>55%), 24-h RR interval variability (RRV) indexes (NN, SDANN, SDNN index, r-MSSD) and 24-h QT and Bazett-corrected QT (QTc) were determined, and groups were matched for age, body surface area, and left ventricular ejection fraction, reducing biases in RRV. The peak differences () between the highest and lowest RRV and QT indexes were extracted from nocturnal (1 am-6 am) and daytime (1 pm-6 pm) hourly assessed segments, respectively. Pearsons correlation (r) and Kruskal-Wallis ANOVA were used to compare groups. CD4+ count correlated positively with NN (r = 0.45; P = 0.003). There were no significant differences in daytime NN among groups. Nighttime SDNN index (P = 0.01), nighttime r-MSSD (P = 0.003), NN (P = 0.01), SDNN index (P = 0.03) and r-MSSD (P = 0.004) were significantly lower in group 3 than in the other groups. Expected nighttime QTc-interval lengthening was not observed in all groups. In perinatally HIV-infected preschool children with preserved left ventricular systolic function, parasympathetic-mediated autonomic dysfunction parallels immune status, impairing both RRV and circadian QTc interval adaptation.
