Correlations of the Orthogonal Electrocardiogram and Vectorcardiogram with Constitutional Variables in 518 Normal Men

Abstract

Correlations were computed between 333 different electrocardiographic measurements and constitutional variables of 518 normal men. The variables consisted of age, body weight, height, chest configuration, race, and deviations from ideal weight according to height. The most significant correlations were encountered with age. With every decade of life, QRS amplitude measurements decreased at an average rate of 6.5%. Although less in absolute voltage terms, amplitude decreases with age were even more significant for the ST-T complex where the average decline was 9.75% for each decade. Comparison of records from white and Negro subjects revealed marked differences. Most amplitude measurements were higher in the latter group. Furthermore, configurations of leads X and Y differed significantly, with smaller Q/R ratios in Negroes. These findings strongly suggest reevaluation of diagnostic criteria according to race both for recognition of ventricular hypertrophies and myocardial infarcts. Correlations with chest configuration revealed a large number of differences but their significance level was relatively low. Body weight appeared to exert a stronger influence upon the ECG. Obesity led to decreases in amplitude and QRS rotations in superior and anterior directions. Correlations with deviations from ideal weight, calculated according to body height, did not exceed the significance level of those obtained with weight only. Body height appeared to exert the least influence upon the electrocardiogram. The results of the correlations emphasize the need for stratification of ECG data according to constitutional variables, particularly for age, race, and body weight. Use of this information will lead to enhancement of diagnostic ECG differentiation and serve as a basis for epidemiological investigations, particularly studies on aging.