[Simulation of the heart action: a computer controlled module for the generation of variable flow patterns].

AIM: The development of a computer controlled pump for the generation of variable flow patterns with high reproducibility for simulating the haemodynamics in physiological model circuits. MATERIAL AND METHODS: The module is controlled by an arbitrary function generator. The shape of the flow profile is generated on the PC based on mathematical functions or drawn by hand. The amplified signal drives a DC motor which is coupled magnetically to a geared pumphead. The lack of mechanical coupling ensures smooth running and a complete attenuation of motor vibrations as well as a disturbance-free flow profile. The spectra were analyzed by Doppler-sonography with a 5 - 12 MHz linear probe and with pressure sensors. Silicon tubes were used as simulated vessels and a water-glycerine mixture with particles of cellulose as simulated blood. RESULTS: The generated flow patterns (constant flow and multi-phase patterns) correlate highly with the measured pressure- and velocity profiles. CONCLUSION: The variability and high reproducibility of the flow profiles and the realtime control of the signal parameters make the simulation of dynamic processes and haemodynamic long-time studies feasible. The module developed facilitates detailed studies of high reproducibility with physiological and pathological flow models and with simulated blood.