Correlation coefficients for electrocardiographic and constitutional variables.

The influence of noncardiac factors such as constitutional variables, sex, and age upon the orthogonal electrocardiogram (ECG) and vectorcardiogram was investigated in 300 normal Japanese subjects. Constitutional variables included body height (HT), body weight (WT), deviation from ideal body weight (DIW), chest transverse diameter (TD), chest sagittal diameter (SD), SD/TD ratio, and chest circumference (CC). Among these constitutional variables, HT was found to be the most important determinant of ECG, followed by WT, TD, CC, SD, SD/TD ratio, and DIW, in that order. An increase in HT resulted in the augmentation of magnitudes of a large number of the QRS and ST-T parameters. WT showed almost the same trends as HT. Of the four measurements of the chest configuration under study, TD proved to be the most powerful determinant. An increase in TD led to a significant increase in QRS duration and to a superior and anterior shift of the maximal T vector. The remaining constitutional variables revealed far less significant correlation with ECG measurements than did HT and WT. Besides the constitutional variables, sex and age were also proved to be important ECG determinants. Advancing age had the effect of reducing the magnitude of many of the QRS and ST-T measurements. It is also of interest that a majority of the QRS and ST-T parameters were larger in male than in female patients. It should be emphasized from the results of this study that normal ECG criteria must be established for each ECG determinant.