Fontan patients are doomed to a circulatory failure and many of them will require a circulatory assistance as a bridge to transplantation. The univentricular heart with a total cavopulmonary connection presents a special challenge for the insertion of an assist device. We report a patient in multiple organ dysfunction and failure who was supported by right-sided univentricular assistance. Technically, a new chamber was created between both vena cava for implantation of the inflow cannula, and the extracardiac conduit was used to set the outflow cannula. The patient dramatically recovered and is currently in the best condition for heart transplantation.