The normal adult spatial vectorcardiogram the timed sequence of inscription of the QRSsÊ of the cube and frank systems

The mean instantaneous QRS vectors in 70 normal adults have been studied by using the cube system in all cases and by the Frank system in 20 of these cases. The mean values and the ranges for each 0.01 sec. of the QRS inscription are reported. In the horizontal planes of both systems the 0.01 sec. vector is normally to the right of +90 °. Also, the initial superior duration did not exceed 0.02 sec. and the 0.01 sec. vector did not exceed 30° above the E point. Up to the 0.04 sec. vector the mean of the angular sequence of inscription is the same for both systems for the horizontal plane. The clinical value of understanding the angular inscription sequence of depolarization of the horizontal QRS loop is described.