Wiktionary
n. A method of recording the magnitude and direction of the electrical forces generated by the heart by means of a continuous series of vectors that form curving lines around a central point.
Wikipedia
Vectorcardiography (sometimes abbreviated as VCG) is a method of recording the magnitude and direction of the electrical forces that are generated by the heart by means of a continuous series of vectors that form curving lines around a central point.
Vectorcardiography was developed by E. Frank in the early 1930s. Since the human body is a three-dimensional structure, the basic idea is to construct three orthogonal leads containing all the electric information. The three leads are represented by right-left axis (X), head-to-feet axis (Y) and front-back (anteroposterior) axis (Z).
To calculate Frank’s leads X, Y and Z using the standard leads system, the following expressions are used:
X = -(-0.172 V1 - 0.074 V2 + 0.122 V3 + 0.231 V4 + 0.239 V5 + 0.194 V6 + 0.156 DI - 0.010 DII) (1)
Y = (0.057 V1 - 0.019 V2 - 0.106 V3 - 0.022 V4 + 0.041 V5 + 0.048 V6 - 0.227 DI + 0.887 DII) (2)
Z = -(-0.229 V1 - 0.310 V2 - 0.246 V3 - 0.063 V4 + 0.055 V5 + 0.108 V6 + 0.022 DI + 0.102 DII) (3)
There are different criteria how at to evaluate a vectorcardiogram created by various researchers. Grygoriy Risman presents these different methods, which were developed over half a century and offers an advanced approach called Spatial Vectorcardiometry (SVCM). The original Russian thesis is filed in the Odessa Medical Academy.