A signal processing circuit for controlling operation of an implanted ventricular assist device comprising an input module for receiving one or more signals of a patient from one or more sensors. A processor for processing the received signals is included, the processor configured to compare a total blood output on a left side of the patient's heart with a total blood output on a right side of the patient's heart； determine at least one from the group consisting of the presence of fluid imbalance between the left and right sides of the patient's heart and the absence of fluid imbalance between the left and right sides of the patient's heart based on the comparison； and when the presence of fluid imbalance is determined, control the implanted ventricular device to restore fluid balance between the left and right sides of the patient's heart.
