Prostheses, Heart, Transcutaneously Powered
Definition : Heart prostheses designed for implantation in the chest that include an implantable short-term power source (e.g., a battery). These devices typically consist of a metallic (e.g., titanium) and plastic mechanism with several sealed chambers, a hydraulic pump that creates the force needed for blood circulation, and valves that open and close to let the blood flow from one compartment of the prosthesis to another and then to the circulatory system. The mechanism is electrically connected to other implantable components, including a rechargeable battery that permits limited (e.g., 30 minutes) autonomous functioning of the prosthesis, an electronic controller that monitors and controls the pumping speed, and a coil. Typically, the pumping mechanism is implanted in the chest and is attached to remnants of the left and right atria of the natural heart and to the aorta and pulmonary arteries after removing the heart ventricles. A coil, an electronic control, and a battery are then implanted in the abdomen. The internal battery is recharged by induction across--but without piercing--the skin (i.e., transcutaneously) using a magnetically coupled circuit between the implanted coil and an external coil (a system known as a transcutaneous energy transmission power system). The external coil usually takes the energy from a battery worn by the patient (e.g., attached to the waist). Transcutaneously powered heart prostheses are intended for use as a permanent replacement for the natural heart, although they may be used as a temporary solution ("bridge") until transplantation.
Entry Terms : "Permanent Heart Prostheses" , "Totally Implantable Artificial Hearts" , "Artificial Hearts, Totally Implantable"
UMDC code : 20398