Autonomic modulation at rest and in response to postural change in adolescents with Duchenne muscular dystrophy: a cross-sectional study

Abstract

Background: Analysis of autonomic modulation after postural change may inform the prognosis and guide treatment in different populations. However, this has been insufficiently explored among adolescents with Duchenne muscular dystrophy (DMD). Objective: To investigate autonomic modulation at rest and in response to an active sitting test (AST) among adolescents with DMD. Methods: Fifty-nine adolescents were included in the study and divided into two groups: 1) DMD group: adolescents diagnosed with DMD; 2) control group (CG): healthy adolescents. Participants’ weight and height were assessed. Lower limb function, motor limitations and functional abilities of the participants in the DMD group were classified using the Vignos scale, Egen classification and motor function measurement, respectively. The following variables were assessed before, during and after AST: systolic blood pressure (SBP), diastolic blood pressure (DBP), respiratory rate (f), oxygen saturation and heart rate (HR). To analyze the autonomic modulation, the HR was recorded beat-by-beat. Heart rate variability (HRV) indices were calculated in the time and frequency domains. Results: Differences in relation to groups were observed for all HRV indices, except LF/HF, oxygen saturation, HR and f (p < 0.05). Differences in relation to time and the interaction effect between group and time were observed for RMSSD, SD1, SD2, SD1/SD2, LFms2 and LFnu, HFun, SBP and DBP (p < 0.05). Differences in relation to time were also observed for the indice SDNN, FC and f (p < 0.05). Conclusions: Performing the AST promoted reduced autonomic modulation and increased SBP, DBP and HR in adolescents with DMD.

Alterações Eletrocardiográficas e do Sistema Nervoso Autônomo com a Mudança de Postura em Crianças e Adolescentes com Distrofia Muscular de Duchenne

“…Na literatura, há somente um estudo sobre VFC com mudança de posição de maneira semelhante ao nosso estudo (da posição supina para sentada), o qual foi realizado com 28 adolescentes com DMD com média de idade de 15,0 anos, detectando-se redução vagal e aumento simpático, ou seja, disautonomia quando os dados foram comparados com o grupo de saudáveis. 34 Esse desequilíbrio da regulação autonômica na DMD pode ser explicado por fibrose do nó sinusal, hipometabolismo em giros temporais, úncus, hipocampo e cerebelo, alteração da produção de óxido nítrico, além de perda neuronal. 10 Alterações sinápticas com diminuição de receptores pós-sinápticos do ácido gama-aminobutírico pela deficiência de distrofina no cérebro, como a perda da óxido nítrico-sintase neuronal, também podem explicar aquela disfunção autonômica, assim como os distúrbios cognitivos e de musculatura esquelética.…”

Mitochondria in Duchenne Muscular Dystrophy-induced Cardiomyopathy: A Prospective Therapeutic Target to Improve Treatment Response

“…Systolic blood pressure is typically lower in DMD patients, which complicates the use of these and other standard heart failure medications (McNally et al, 2015). There is, however, a crosssectional study which showed increased systolic and diastolic BP, and heart rate in adolescents with DMD in response to an active sitting test that promoted reduced autonomic modulation (Rodrigues et al, 2021). Of note, it was observed that infusion of the β-1 adrenergic receptor agonist dobutamine in 7-month-old C57BL/10 mdx Langendorff perfused hearts resulted in significantly lower peak systolic pressure, developed pressure, and dP/dtMAX compared to control mice (Stevens et al, 2024).…”