Comparison of the Vectorcardiogram with the Electrocardiogram in the Prediction of Left Ventricular Size

Abstract

The vectorcardiogram has been suggested as an alternative to the electrocardiogram in the diagnosis of left ventricular enlargement. In 107 patients, precordial QRS voltage measurements were compared with vectorcardiographic spatial magnitude measurements in their relationship to angiocardiographically determined left ventricular mass and volume. Sensitivity, specificity, and linear correlations obtained with instantaneous spatial QRS magnitude measurements were similar to those obtained with selected precordial voltage measurements suggested by Sokolow and Grant. Multiple regression analysis incorporating time-strength integrals of the spatial QRS correlated more closely with left ventricular mass (R = 0.75) and total volume (R = 0.80) than did similar analysis using precordial voltages (R = 0.71). These differences are statistically significant ( P = <0.01) but reduce the remaining variability of the electromotive-left ventricular size relationship by only 7 to 14% and leave 30 to 40% of the total variability unexplained. These findings do not support a large practical advantage for the vector-cardiogram over the electrocardiogram in the prediction of left ventricular size.