The present disclosure provides for a method, control device, and implantable system, for acquiring a plurality of flow rate data points over time, each data point indicative of a flow rate of blood through the pump, calculating, based on the plurality of acquired flow rate data points, a value characterizing one or more features of a waveform formed from the plurality of flow rate data points; and determining, based on the value, the presence or absence of a suction condition in the pump.