Nocturnal Heart Rate Variability Spectrum Characterization in Preschool Children With Asthmatic Symptoms

Area of Science:

• Pediatrics
• Cardiology
• Respiratory Medicine

Background:

• Asthma is a chronic childhood lung disease where early diagnosis is crucial to prevent airway obstruction.
• Abnormal parasympathetic nervous system (PSNS) activity is implicated in asthma pathogenesis.
• Cardiac vagal control, reflected in heart rate variability (HRV), may indicate PSNS activity.

Purpose of the Study:

• To propose and validate a novel index, peakness ($\wp$), to characterize the high frequency (HF) component of HRV.
• To assess the relationship between $\wp$ and the risk of developing asthma in preschool children.
• To investigate the association between $\wp$, sympathovagal balance, and PSNS adaptability in high-risk children.

Main Methods:

• Development of three $\wp$ index implementations using electrocardiogram (ECG) and impedance pneumography (IP) data.
• Classification of preschool children into high-risk and low-risk groups for asthma development.
• Analysis of spectral distribution of the HF component of HRV and sympathovagal balance.

Main Results:

• Children at high risk for asthma exhibited significantly 'peakier' HF components in their HRV ( $p < 0.005$).
• High-risk children also showed a reduced sympathovagal balance.
• The $\wp$ index effectively differentiated between risk groups.

Conclusions:

• The proposed peakness ($\wp$) index is a promising tool for early asthma risk assessment in children.
• Findings suggest a link between a lack of PSNS adaptability and a high risk of developing asthma.
• Abnormal cardiac vagal control, as measured by $\wp$, may serve as an early biomarker for pediatric asthma.