Modulação autonômica e índice de massa corporal de crianças com síndrome de down

Abstract

The aim of this study is to analyze the autonomic modulation in children with Down syndrome (DS). The study was conducted with a convenience sample of children with DS and without heart disease, from the Genetics Clinic of the Hospital Infantil Darcy Vargas and APAE São Paulo, São Paulo, SP, Brazil. The control group was matched for sex and age. The analysis of autonomic modulation was performed using the indices of heart rate variability (HRV). The children remained in the supine position with spontaneous breathing for 20 min. Heart rate was recorded beat-to-beat. HRV analysis was performed in time and frequency domain. For data analysis, we used Student's t test: unpaired and Mann-Whitney. It was considered statistically significant at p < 0.05. From 75 children with DS, 50 were excluded, a total of 25 children [16 boys, 8.6 (1.4) years] participated in this study, and the control group also consisted of 25 children [16 boys, 9.0 (1.2) years] without the syndrome. The BMI of the volunteers with DS was higher than the controls [19.1 (2.9) vs. 15.8 (1.2), p < 0.0001]. There were differences between groups in the indices in frequency domain: LFms2 [1242.1 (788.25) vs. 786.44 (481.90), p = 0.040], LFun [69.104 (11.247) vs. 57.348 (11.683), p = 0.0004], HFun [30.896 (11.247) vs. 42.520 (11.634), p = 0.0004] and LF/HF [2.594 (1.104) vs. 1.579 (0.9982), p = 0.0004]. No differences were observed in time domain indices. The results indicate increased indices representing the sympathetic branch of the autonomic nervous system and those that indicate the overall modulation in children with DS.

A síndrome de Down (SD) é uma anomalia genética no vigésimo primeiro par de cromossomos, apresentando um cromossomo 21 extra, que se caracteriza por alterações físicas e mentais; entre elas: hipotonia muscular e cardiopatias congênitas. Objetivo: caracterizar a modulação autonômica e o perfil antropométrico de crianças com síndrome de Down. Método: será realizado estudo transversal, com amostra de conveniência de crianças de sete a dez anos de idade, usuárias do serviço do Ambulatório de Especialidades da Faculdade de Medicina do ABC. As características biológicas estudadas serão peso, estatura, composição corporal e modulação autonômica. O estudo da modulação autonômica será realizado por meio da análise de índices de lineares (no domínio do tempo e da frequência) e não lineares (no domínio do caos) de variabilidade da frequência cardíaca.