Racial variations in electrocardiograms and vectorcardiograms between black and white children and their genesis

Area of Science:

• Pediatric Cardiology
• Biomedical Engineering
• Human Physiology

Background:

• Current pediatric electrocardiogram (ECG) and vectorcardiogram (VCG) standards do not account for racial differences.
• Clinical observations suggest distinct ECG patterns in black versus white children.

Purpose of the Study:

• To investigate and quantify racial differences in ECG and VCG parameters in normal children.
• To explore potential underlying causes for observed racial variations in cardiac electrical activity.

Main Methods:

• Collected biographic data, blood pressure, hemoglobin, ECG, Frank VCG, and echocardiograms from 244 normal children (124 black, 120 white) aged 3-17 years.
• Analyzed 144 measured parameters and 57 computed variables, stratifying by age groups (3-5, 6-10, 11-14 years).
• Compared cardiac structure via echocardiography to correlate with ECG/VCG findings.

Main Results:

• No significant racial or sex differences in ECG/VCG were found in the 3-5 year age group.
• By age 6-10, black children showed greater ECG/VCG amplitudes (e.g., R wave, S wave, SV1+RV6) compared to white children (p<0.01).
• In 11-14 year olds, black males exhibited higher ECG/VCG values than white males, while no differences were noted between girls. Echocardiograms revealed thicker left ventricular posterior walls in black children where ECG-VCG differences were observed.

Conclusions:

• Racial differences in ECG and VCG parameters emerge in children by age 6-10 and are more pronounced in males by adolescence.
• These electrophysiological variations are associated with differences in cardiac morphology, specifically left ventricular wall thickness.
• Pediatric ECG/VCG interpretation guidelines may need to incorporate race-specific normal ranges.