From dotted lines to fetal cardiology: the pioneering contribution of Xin-Fang Wang (1934-2021).

(a) When the ultrasound beam was perpendicular to the direction of swing of the fetal heart during contraction and relaxation, with the heart appearing to swing left and right, the motion would be captured by the beam intermittently, and an M-mode tracing would show a dashed line (arrows). The earliest article published on fetal echocardiography in German was by Kratochwil and Eisenhut in 19671, and that in English was by Fred Winsberg in 19722. In 1963, they used an M-mode ultrasound device made by Wuhan Radio Equipment Company (c) to display the earliest M-mode fetal echocardiograms (Figure 2). gl In the early 1960s, they first observed "flashing dots" above the pelvic area of pregnant women using an A-mode ultrasound device, made by a Shanghai shipyard. [Extracted from the article]