Method and systems control a rotational speed of a blood pump during ventricular diastole. A method includes controlling a blood pump in accordance with a first segment operational mode. A controller monitors the blood flow rate through the blood pump. The controller determines, based on the blood flow rate, whether continued controlling of the blood pump per the first segment operational mode would result in the blood flow rate through the blood pump being less than a target minimum blood flow rate. In response to a determination that continued controlling of the blood pump per the first segment operational mode would result in the blood flow rate through the blood pump being less than the target minimum blood flow rate, the controller controls the rotational speed of the blood pump so that the blood flow rate through the blood pump is approximate to the target minimum blood flow rate.