Circadian cardiac autonomic function in perinatally HIV-infected preschool children

• Published in: Brazilian journal of medical and biological research Vol. 42; no. 8; pp. 722 - 730
• Main Author: Benchimol-Barbosa, P R
• Format: Journal Article
• Language: English
• Published: Brazil Associação Brasileira de Divulgação Científica 01-08-2009
• Subjects: Autonomic nervous system; Autonomic Nervous System - immunology; Autonomic Nervous System - physiopathology; BIOLOGY; CD4-CD8 Ratio; Child, Preschool; Circadian rhythm; Circadian Rhythm - immunology; Circadian Rhythm - physiology; Cross-Sectional Studies; Electrocardiography, Ambulatory; Female; Heart Conduction System - immunology; Heart Conduction System - physiopathology; Heart Rate - immunology; Heart Rate - physiology; Heart rate variability; HIV Infections - immunology; HIV Infections - physiopathology; Human immunodeficiency virus infection; Humans; Male; MEDICINE, RESEARCH & EXPERIMENTAL; Perinatally HIV-infected children; Viral Load; Circadian rhythm; Human immunodeficiency virus infection; Autonomic nervous system; Heart rate variability; Perinatally HIV-infected children
• ISSN: 0100-879X; 1414-431X; 1414-431X; 0100-879X
• DOI: 10.1590/S0100-879X2009000800006

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.