About this Research Topic
Despite thousands of articles addressing heart rate variability (HRV) in healthy subjects and patients with various clinical conditions published during the last decades, our understanding of the development of cardiac autonomic nervous system is still very limited. During individual growth the autonomic control may exert various effect on cardiac rhythm, i.e. it may change the rate and the variability. However, these two quantities are associated with each other due to both mathematical and physiological reasons. Consequently, any changes in heart rate (HR) usually entail simultaneous changes in HRV. The most common developmental phenomenon is the reduction of HR with a child’s age, which in turn may influence HRV. Nevertheless it still to be determined to what extent the alterations of HRV during growth and development result from the HR changes. The normalization of HRV for the prevailing HR may liberate HRV form the influence of HR and enable the objective assessment of the pure variability. Moreover, other autonomic markers such as deceleration capacity and indices of baroreflex sensitivity also reveal correlation with HR and may be affected by the HR developmental changes. It is therefore critical to assess both tonic and reflex autonomic markers independently of average HR, i.e. by employing the normalization procedure. Such an approach may allow to determine the role of HR in the autonomic nervous system maturation.
Another uncovered field in paediatrics is the non-linear heart rate dynamics and their developmental perturbations. A number of non-linear autonomic markers have been proposed and tested in adult populations, however, little is known on how these markers behave during the growth of an individual and what their relationship with HR is. It is also unclear whether the cardiac autonomic function gets more linear or non-linear with age in healthy children. Deeper explorations of this field may help to create a developmental model of the autonomic function.
Lastly, there appears a question how all the aforementioned aspects relate to different abnormalities and diseases in paediatric populations, i.e. whether HR and its variability reveal distinct roles in the pathology of young people and could be linked to increased risk of the complications of the disease.
This Research Topic will cover all issues associated with cardiac autonomic function in children and adolescents. Researchers dealing with these topics are welcome to submit related manuscripts.
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