Dipole and Quadrupole Measurements of an Isolated Turtle Heart

An equivalent cardiac generator, specifically the multipole model, was evaluated for an isolated turtle heart located in a spherical volume conductor. The dipole and quadrupole contributions to the potential field were calculated using weighted integrals of the surface distributions. This procedure has the advantage of eliminating errors due to the truncation of the multipole series. The dipole and quadrupole effects were calculated for the QRS portion of the cardiac waveform. A significant quadrupole contribution was found to exist.