An on-line interactive, modular, menu-driven microcomputer-based data acquisition and analysis system was designed and implemented. This system includes a low-cost commercial desk-top graphics computer with a modular construction. All these operations are performed using extended BASIC "CALL" statements. The system is designed to be used in a cardiovascular research and laboratory environment where the assessment of hemodynamic and cardiodynamic function includes routine measurements of pressure and flow. In addition, the measurement of regional and global left ventricular chamber dimensions have been implemented. The modular design of the software system is "human-engineered" to enable a simple, cost effective computer system to perform physiological measurement and control. Extended BASIC language instructions provide the casual computer user with a simple yet effective means of implementing on-line data acquisition, analysis and graphic production and display.