An ultrasonic diagnostic imaging system is described by which a first sequence of ultrasound images of an organ such as the heart is acquired at a first image acquisition rate. The first sequence preferably images a larger volume or area in which a region of interest is located. Then a second sequence of three-dimensional ultrasound images of a sub-volume covering a part of anatomy of interest in the first sequence is acquired at a second image acquisition rate which is greater than the first acquisition rate. A third sequence of three-dimensional ultrasound images of a reference sub-volume is acquired at the second image rate. The second and third sequences of three-dimensional images are compared, enabling a clinician to focus on synchronism defects in the anatomy of interest with more precision and with a faster acquisition time.