A ventricular assist device, comprising: a control circuit for controlling operation of the ventricular assist device in a patient, the control circuit comprising: a memory for storing instructions; and a processor for executing the instructions stored in the memory, the processor being configured to: obtain flow rate data points from the ventricular assist device, the flow rate data indicating a rate of flow of blood exiting the ventricular assist device; identify a portion of the flow rate data points associated with systole of a given cardiac cycle of the patient, the identifying of the portion of the flow rate data points associated with systole of a given cardiac cycle of the patient includes: determining a running average of flow rate; comparing the obtained flow rate data points to the running average, wherein a flow rate data point crossing above a crossover value of the running average is indicative of a beginning of systole, and a flow rate data point crossing below a crossover value of running average is indicative of an end of systole; and identifying the portion of flow rate data points above the running average as associated with systole; repeatedly determine whether the patient's aortic valve is one of open and closed based on the obtained flow rate data points; and if it is determined that the patient's aortic valve is closed based on one or more determinations, reduce an operating speed of the ventricular assist device. a memory for storing instructions; and a processor for executing the instructions stored in the memory, the processor being configured to: obtain flow rate data points from the ventricular assist device, the flow rate data indicating a rate of flow of blood exiting the ventricular assist device; identify a portion of the flow rate data points associated with systole of a given cardiac cycle of the patient, the identifying of the portion of the flow rate data points associated with systole of a given cardiac cycle of the patient includes: determining a running average of flow rate; comparing the obtained flow rate data points to the running average, wherein a flow rate data point crossing above a crossover value of the running average is indicative of a beginning of systole, and a flow rate data point crossing below a crossover value of running average is indicative of an end of systole; and identifying the portion of flow rate data points above the running average as associated with systole; repeatedly determine whether the patient's aortic valve is one of open and closed based on the obtained flow rate data points; and if it is determined that the patient's aortic valve is closed based on one or more determinations, reduce an operating speed of the ventricular assist device. obtain flow rate data points from the ventricular assist device, the flow rate data indicating a rate of flow of blood exiting the ventricular assist device; identify a portion of the flow rate data points associated with systole of a given cardiac cycle of the patient, the identifying of the portion of the flow rate data points associated with systole of a given cardiac cycle of the patient includes: determining a running average of flow rate; comparing the obtained flow rate data points to the running average, wherein a flow rate data point crossing above a crossover value of the running average is indicative of a beginning of systole, and a flow rate data point crossing below a crossover value of running average is indicative of an end of systole; and identifying the portion of flow rate data points above the running average as associated with systole; determining a running average of flow rate; comparing the obtained flow rate data points to the running average, wherein a flow rate data point crossing above a crossover value of the running average is indicative of a beginning of systole, and a flow rate data point crossing below a crossover value of running average is indicative of an end of systole; and identifying the portion of flow rate data points above the running average as associated with systole; repeatedly determine whether the patient's aortic valve is one of open and closed based on the obtained flow rate data points; and if it is determined that the patient's aortic valve is closed based on one or more determinations, reduce an operating speed of the ventricular assist device.