Table 1: Clinical characteristics of the study population (n = 136).
In the 2D-clips of both operators, the IVS was located with ‘apex oblique up’ in 61.76 % (beginner) and in 64.71 % (expert). The mean fetal heart rate was 148 beats per minute (bpm). On average, a frame rate of 76 Hz (beginner) and 73 Hz (expert) in the study collective was achieved. In 43% (beginner) and 7% (expert) of the 2D-clips, the 80 Hz frame rate threshold was exceeded (Table 2).