Racial contrasts of blood pressure levels in two southern, rural communities

Subtle electrocardiographic changes in children with high levels of blood pressure

One hundred thirty-four children, aged 8 to 17 years, were studied to evaluate differences in left ventricular (LV) voltages with mid-range and high blood pressure (BP) levels. The children were selected from 1,604 children after a series of replicate measurements of BP over a 4-month period. Ninety children were selected from those whose BP persisted at the upper 10% and 44 whose BP remained at the middle range (between the fiftieth and sixtieth percentiles). Factors influencing the electrocardiographic voltage (i.e., triceps skinfold, weight, age, race and sex) were also analyzed. Children in the upper 10% of BP levels showed larger LV voltages R1 + SV1 + RV4 than did those in the middle range. This difference was strongly influenced by larger voltages shown by white children. Males showed larger voltages than females using the same index. Triceps skinfold, age and BP account for 6 to 14% of the electrocardiographic variability in the high BP group. Thus, subtle voltage differences in children with early elevations of BP levels do occur. The larger ventricular voltages on the electrocardiogram may represent an early sign of increased LV mass, as has been noted by echocardiography.