A Television Tracking System has been developed to measure the motion of beating Heart Cells in-vitro. The performance of these cells is used to monitor the presence of a circulating Myocardial Depressant Substance in Humans with septic shock. Beating myocardial cells were placed in a petri dish on the microscope stage at an inverted microscope and imaged by a television camera. Motion voltages were developed from the resultant television video by the tracking system.