Preliminary clinical experience with a new radioisotope-powered cardiac pacemaker.

A small light-weight nuclear-powered pacer has been developed. The pulse generator weight 61 Gm. and occupies a volume of 33 sq. cm. It is a standard R-wave inhibited (VVI) demand pulse generator. The unit has met all United States and foreign atomic energy commission safety specifications including mechanical shock, industrial fire, accidental crush, cremation, impact, and corrosion. Its calculated life is in excess of 20 years. The unit has been shown to be insensitive to electromagnetic interference (EMI) over a wide range of commonly encountered sources of interference. An extensive dog testing program has been carried out and is continuing. The United States Atomic Energy Commission (AEC) has issued a license to conduct clinical trials. These began in October, 1974, and a total of 30 units of 30 units have been implanted so far. An equal number of chemical battery-powered pulse generators has been implanted in a control series of 30 patients. Preliminary results have been gratifying.