The principal barrier to the extended use of the total artificial heart is infection that is centered on the biomaterial constituting the prosthetic device and exacerbated by the surrounding damaged tissue. Ultrastructural studies of total artificial hearts removed from two patients indicate a failure of true tissue integration and diffuse, adhesive bacterial colonization of biomaterial surfaces. Biomaterials are, in part, susceptible to infection because, at the present state of the art, they are usually not well integrated with host tissue or, if hemodynamic, not optimally biocompatible or antiadhesive.