An Experimental Study of the Multipole Series that Represents the Human Electrocardiogram

A multipole equivalent cardiac generator was investigated using a human subject, a torso tank, and a special multipole probe. Data from seventeen leads were fitted, by the method of least squares, to a dipole and to a dipole-plus-quadrupole source located at two different origins. In all cases the inclusion of the quadrupole improved the lead correlation coefficients. The quadrupole was found to contribute significantly to the surface potential at the beginning of the R wave and during the R-S portion of the QRS complex. This quadrupolar contribution could not be removed by origin shifting.