https://www.cnet.com/news/this-artificial-heart-can-save-the-youngest-patients/

To buy that time, Juniper's doctors implanted a Berlin Heart — a ventricular assist device (VAD) system that helps the smallest, sickest babies survive until a new heart becomes available.

VAD systems — which combine surgically inserted pumps with external controls and power supplies — have come a long way since 1963, when famed cardiac surgeon Dr. Michael DeBakey implanted the first such device. VADs have since become smaller, less obtrusive and easier to wear. More than a half-dozen devices have been approved for sick adults who need a stopgap to keep them alive while waiting for a transplant. Super small babies don't have those options.