Racial differences in electrocardiograms and vectorcardiograms between black and white adolescents.

In a previous study of 244 normal children, we detected higher leftward, posterior and inferior voltages in blacks than in whites in two groups: 6- to 10-year-old children and in 11- to 14-year-old boys; no difference was found in 3-to-5-year-old children, or 11- to 14-year-old girls. The purpose of this study was to determine if such race-related voltage differences are also present in 15- to 19-year-old adolescents. Biographic data, blood pressure and hemoglobin values, electrocardiogram (ECG), Frank vectorcardiogram (VCG) and echocardiogram were obtained in 59 normal 15- to 19-year-olds (28 blacks and 31 whites); 144 measured parameters and 57 computed variables were analyzed. Many sex-related differences (p less than 0.05 to 0.001) were seen in both races. R in leads I, AVL and V6, S in V1, and sum of SV1 and RV6 in the ECG and X to left, terminal X to right and Y inferior in the VCG were higher (p less than 0.05 to 0.01) in black males than in white males. However, no such differences (p greater than 0.05) were observed between black and white females. To understand the causes of these differences, comparison of the biographic data, blood pressure, hemoglobins and echocardiograms were made. The height, weight, body surface area, chest circumference, AP diameter of the chest, diastolic and systolic blood pressure and left ventricular (LV) dimension were similar (p greater than 0.1) in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)