Organ transplantation is a medical therapy that poses persistent risks of tissue rejection that are managed on a continual basis by immunosuppressive drugs such as cyclosporine, prednisone, and azathioprine. However, despite the effectiveness of these antirejection medications widespread application of this technology has been, and continues to be, severely limited by the shortage of suitable donor organs. Artificial organ systems constructed by man‐made materials have an advantage over tissue‐based therapies insofar as they are not subject to rejection problems or limited by organ availability. Still, the development and use of these synthetic devices present its own unique set of challenges that have yet to be completely overcome. The reason is simple. The heart, liver, kidney, and other internal organs perform functions that are not fully understood by modern science. Artificial organs for implant therefore provide, at best, an incomplete solution to a complex medical problem. While the use of artificial organs can be satisfactory in many cases, these interventions generally involve the implantation of nonbiological elements within the body, raising issues of biocompatibility, and requiring stringent sterilization protocols. Moreover, the use of implanted man‐made structures that contact with circulating blood (e.g., heart valves) has been associated with an increased incidence of thromboembolic events. This article considers the energy requirements and sensor/control aspects of artificial hearts and ventricular assist devices designed to augment blood flow and tissue perfusion levels provided by the failing heart.