Normal limits of the derived vectorcardiogram in Caucasians

The derived vectorcardiogram (dVCG) can be obtained from three orthogonal leads X, Y, Z, which are synthesized from the conventional 12-lead ECG by one of a number of mathematical techniques. The application of the dVCG in routine cardiological practice has the advantage of not requiring extra recording electrode other than those used for the conventional 12 electrocardiographic leads, and offers the simultaneous availability of additional dVCG diagnostic information. In this study, the dVCGs were obtained using the inverse Dower method from 1555 apparently healthy Caucasian individuals (884 men and 671 women) and were analysed to determine the age and sex dependent normal ranges of vector measurements in a Caucasian population. The vectorcardiographic parameters measured included the directions of inscription of the QRS vector loops, the magnitude of initial 20 and 30 ms QRS vectors and the direction of the initial 20 ms QRS vector. The maximal spatial QRS vector magnitude, as well as the maximal QRS and T vector magnitudes in the frontal, horizontal, and right sagittal planes, were observed to decrease significantly with advancing age in both sexes (P < 0.001) and were significantly larger in men in all age groups (P < 0.001). The observations from the current study illustrate the significant age and sex dependent differences in the normal ranges of dVCG parameters. These are of potential importance for diagnostic applications.