1. A method for automatically selecting ultrasound images associated with a phase of a heart cycle, the method comprising: performing each of the following with a medical diagnostic ultrasound imaging system: (a) storing a plurality of sets of ultrasound images, each of the plurality of sets comprising a plurality of ultrasound images, each of the plurality of ultrasound images associated with a different phase of heart cycle, wherein each ultrasound image is characterized by a time interval between an acquisition time of the ultrasound image and a reference phase in the heart cycle; (b) retrieving a stored user-preference of a phase of the heart cycle, the user-preference being stored for selection of ultrasound images, wherein the user-preference is stored in the medical diagnostic ultrasound imaging system prior to acquisition of the plurality of sets of ultrasound images and, wherein the phase specified in the stored user preference is characterized by a time interval between the phase specified in the stored user preference and the reference phase; (c) determining a tolerance range about the phase of the heart cycle, the tolerance range having a temporal width that is based on the time interval between the phase specified in the stored user preference and the reference phase; (d) automatically selecting a plurality of ultrasound images from each heart cycle that are characterized by a time interval that is within the tolerance range; and (e) displaying the automatically-selected plurality of ultrasound images.