Racial and sexual differences in the standard electrocardiogram of black vs white adolescents

Standard 12-lead electrocardiograms were recorded in 114 healthy adolescents to substantiate possible influences of race and sex on the "juvenile pattern" (increased precordial voltages of QRS complex, precordial T wave inversions, and ST-segment elevations considered pathologic in adults) in this age group. Black male subjects had the highest precordial QRS amplitudes and the highest incidence of biphasic or negative precordial T waves and ST-segment deviations. In white male subjects, these findings were less pronounced but were more evident than in black or white female subjects. Results indicate the following: (1) race-specific and sex-specific normal electrocardiographic standards should be developed in adolescents; (2) criteria for left ventricular hypertrophy are race-specific and sex-specific and should be tested against independent anatomic or physiologic information in adolescents with left ventricular overload; and (3) the "juvenile pattern" may be viewed as a predictable continuum of age-related changes starting in childhood and progressing through adolescence on to later life.