Abstract: A pump system is provided comprising a diaphragm fluid pump which can be fluidically connected to a heart and/or at least one blood vessel by means of an inlet cannula and an outlet cannula and is adapted for generating a pulsatile fluid flow for supporting a cardiac activity of the heart, a working pressure source connected to the diaphragm fluid pump by means of a pressure line and adapted for providing a working pressure for driving the diaphragm fluid pump, a control unit adapted for controlling the working pressure, a first flow sensor adapted for detecting a first cannula flow signal corresponding to an inlet flow in the inlet cannula or an outlet flow in the outlet cannula, a working pressure sensor adapted for detecting a working pressure signal corresponding to the working pressure in the pressure line.