The Discordant Electrocardiogram

The QRS complex represents the excitation wave in the ventricles, and it is normally upright in both the axial and the transverse leads. Under certain conditions it has a downward direction in one of the leads. When this is the case, discordant curves are present as opposed to the normal, concordant curve. In the absence of other abnormalities, discordance by virtue of a downwardly directed QRS in the transverse lead is right axis deviation or preponderance and discordance of the opposite type is left axis deviation or preponderance. In a simple strip of mammalian heart muscle with parallel fibers the electrical curves inscribed vary in form and direction in accordance with alterations in the position of the leading electrodes with reference to the muscle, although the direction in which the excitation travels and the line of the leading remain unaltered.¹Since the form of these curves resembles the common variations