An ultrasonic diagnostic imaging system produces a spectral Doppler display on which automated measurements may be made. The waveform is analyzed by the ultrasound system to identify the peak velocity of each cardiac cycle of the sequence, and the cardiac cycle with the highest peak velocity value. When a measurement tool is launched, the system displays the highest peak velocity cycle and makes the selected measurement on the data of that heart cycle. The system may advantageously use a peak velocity tracing algorithm in support of this feature. The technique can be used with a variety of measurement tools.