Sensors for catheter pumps are disclosed herein. The catheter pump can include a catheter assembly comprising a catheter and a cannula coupled to a distal portion of the catheter. The cannula can have a proximal port for permitting the flow of blood therethrough. The catheter assembly can include a sensor to be disposed near the proximal port. A processing unit can be programmed to process a signal detected by the sensor. The processing unit can comprise a computer-readable set of rules to evaluate the signal to determine a position of the cannula relative to an aortic valve of a patient.
