Interaction Between Heart Rate Variability and Heart Rate in Pediatric Population

Area of Science:

• Pediatric Cardiology
• Autonomic Nervous System Function
• Cardiovascular Physiology

Background:

• Heart rate variability (HRV) is influenced by heart rate (HR).
• Understanding HR's impact on HRV in children is crucial for accurate assessment.
• Previous studies have not fully elucidated age- and sex-related HRV differences normalized for HR.

Purpose of the Study:

• To evaluate the effect of heart rate (HR) on heart rate variability (HRV) in children.
• To determine if HRV indices, normalized to HR, are sex- and age-related.
• To investigate the influence of autonomic nervous system maturation on HRV in pediatric populations.

Main Methods:

• Short-term ECG recordings in 346 healthy children across four age subgroups (6-13 years).
• Analysis of standard time and frequency domain HRV parameters and HR.
• Normalization of HRV parameters to prevailing HR to assess HR's impact.

Main Results:

• Standard HRV measures did not differ significantly between age subgroups.
• HR significantly decreased with age and was the strongest determinant of HRV.
• Normalized HRV showed a significant decrease with age, an effect masked by HR changes in standard HRV measures.
• Sex-related differences in standard HRV were explained by HR differences between boys and girls.

Conclusions:

• HR is a significant determinant of HRV in the pediatric population.
• Normalized HRV decreases with age in healthy children, reflecting autonomic nervous system maturation.
• Apparent constancy of standard HRV with age is due to concurrent HR reduction.