Powering an artificial heart: birth of the inductively coupled-radio frequency system in 1960.

In mid-1960, our group initiated a research program focused on studying pain-free electromagnetic methods of furnishing energy to an implanted heart without piercing the skin. During the last half of 1960, we derived a detailed theoretical rationale for a radio frequency system involving inductive coupling between a thin, small, pancake-shaped coil on the surface of the chest and a similar coil either within the chest or, alternatively, subcutaneously. Having an efficiency of about 95%, the system was evaluated in dogs at 50 and 69 W levels, respectively. Thus was born what is now termed the transcutaneous energy transformer (TET).