A new system for studying mechanical activity of freshly isolated cardiac myocytes from up to four experimental groups simultaneously is described. Suspensions of cardiac myocytes isolated from adult rat hearts were drawn into microhematocrit capillary tubes, which were then mounted in parallel fashion between two four-channel tubing manifolds placed on the movable stage of an inverted microscope. Within a few minutes, cells settled and attached to the bottom of the tubes and then could be superfused with various test solutions. The system allowed for electrical field stimulation, rapid changes in bathing solutions, control of temperature, and simulation of ischemia and reperfusion with measurements of the effects of such interventions on both populations of cells (low power survey) and individual myocytes (high power). Myocyte responses to these various interventions are described. The primary advantage of this system is the ability to conduct experiments on cardiac myocytes isolated concurrently from multiple experimental groups at the same time and under identical conditions.