Movie 2.

During the microinjection procedure, the needle is advanced through the uterus and into the fetal left atrium while avoiding critical structures such as the fetal limbs and the vitelline vessels. In this view, the needle tip is in the same imaging plane as the echogenic left atrium walls and appears bright on B-mode ultrasound. Prior to delivery of the embolizing agent, the needle tip should be localized centrally within the left atrium cavity, surrounded by both the top and bottom walls of the left atrium.