A two-computer-based 4-channel stimulator and action potential (AP) analysis system was developed to assist the cardiac electrophysiologist in data collection and control of experiments in a standard multiple microelectrode tissue bath. The two-computer system is made up entirely of standard, readily available hardware items. AP analysis is done by an IBM Personal Computer. The analysis of individual or grouped APs allows derivation of conduction time, maximum amplitude, resting potential, upstroke velocity, and action potential duration. These data may be stored on disk for later trend plots or transferred to another computer for statistical analysis. The stimulator was implemented with a separate single board microcomputer, which is controlled by the larger analysis computer.