Effect of hyperventilation of precordial T waves of children and adolescents

Following the taking of 12-lead routine electrocardiograms, three precordial leads were recorded before, during, and after 10 to 15 seconds of voluntary hyperventilation in 296 students, ranging in age from 8 to 17 years. Fifteen per cent of the total group, comprising 212 Caucasians and 84 Negroes, inverted one or more previously upright precordial T waves following hyperventilation. The incidence of T-wave inversion in children 12 years of age and under was nearly four times greater in Caucasians than in Negroes. There was no significant difference when the older Negro and Caucasian students were similarly compared. Sinus tachycardia, T-wave flattening, and "tucking," short of frank inversion, as well as junctional depression of the ST segment, were commonly seen following hyperventilation. The similarity of the hyperventilation-induced T-wave inversion in children to those previously documented in adults is noted, and the clinical implication of this study requires continued cognizance of the occurrence of "nonpathological" T-wave inversion in adults, so as to avoid iatrogenic heart disease.