By enclosing these three spatial vectors with a continuous line, a vector loop can be created which accurately orients the uncancelled electrical forces in the frontal plane. Note that the MAIN electrical axis, i.e. the axis of the largest component of the QRS complex; and the MEAN electrical axis, i.e. the average of the axes of the various components of the QRS complex, are quite similar in this example and the two terms are often used interchangeably. This type of vectorial display is very useful in visualizing the abnormalities in inter- and intra-ventricular conduction that occur with the bundle branch and fascicular blocks, with trans-mural myocardial infarctions and with ventricular pre-excitation.