Heart rate variability in children with obstructive sleep apnea: a systematic review

Abstract

Obstructive Sleep Apnea (OSA) is a common respiratory disorder characterized by recurrent nocturnal episodes of breathing interruption due to the total or partial collapse of upper airway1 and affects 1.25.7% of children.2 The peak of incidence occurs at 2-8 years and the most common cause of OSA in children is enlarged tonsils and adenoids.2,3 Moreover, OSA is associated with morbidity that involves central nervous system (CNS), cardiovascular and metabolic systems.4 The recurrent hypoxia is suggested as the main cause of altered autonomic nervous system (ANS) in those patients.5,6 The obstructive episodes lead not only to hypoxia, but also intermittent hypercapnia, which can modulate the autonomic nervous system of OSA patients. Main consequences of hypoxia and hypercapnia include increased of sympathetic tone and sympathetic responsiveness as well as sympathetic-parasympathetic imbalance.4 There is also evidence that OSA alters heart rate response and systemic blood pressure, which can contribute to cardiovascular morbidities when adults.5 To evaluate the integrity of ANS is commonly used a non-invasive method named heart rate variability (HRV). HRV represents the oscilations of heart rate (HR) and it’s considered a measure of neurocardiac function that reflects ANS dynamics.7 Some pathologies, such as respiratory and cardiovascular diseases, shows lower HRV pattern, which is consistent with and abnormal adaptability of ANS, whereas healthy individuals exhibit higher HRV indices meaning an ANS adaptable and dynamically responsive to change.8 To address this issue, the aim of this study was to review whether heart rate variability was altered in children with obstructive sleep apnea. Methods