Normal values of signal-averaged electrocardiographic parameters and QT dispersion in infants and children

Area of Science:

• Pediatric Cardiology
• Electrophysiology
• Biomedical Engineering

Background:

• Ventricular arrhythmias pose a risk, with ventricular late potentials and QT interval dispersion as key indicators.
• Established normal values for these parameters in adults may not be applicable to pediatric populations.
• Understanding age-related changes in electrocardiographic parameters is crucial for accurate risk assessment in children.

Purpose of the Study:

• To investigate the age dependency of signal-averaged electrocardiographic parameters and QT dispersion in healthy children.
• To establish age-specific reference values for these electrophysiological markers in pediatric subjects.

Main Methods:

• Signal-averaged electrocardiograms were analyzed in 111 normal children aged 5 days to 16 years.
• Measurements included filtered QRS duration, low-amplitude terminal signal duration, and root mean square of the last 40 ms.
• QT dispersion was calculated and analyzed in relation to age.

Main Results:

• Filtered QRS duration and low-amplitude terminal signal duration increased significantly with age (p<0.001).
• Root mean square of the last 40 ms decreased with age, stabilizing after 10 years (p<0.001).
• QT dispersion showed no significant age-dependent variation, with a mean of 36 ± 13.7 ms.

Conclusions:

• Age must be considered when interpreting signal-averaged electrocardiogram parameters in children.
• QT dispersion measurements do not require age-specific adjustments in pediatric populations.
• A weak correlation was observed between QT dispersion and filtered QRS duration.