Technological progress in pacemaker design: hermetic sealing

Clinical statistics covering the life of pacemakers powered by mercury batteries show that an average life of 3 years has not yet been obtained. Strangely, the life does not seem to depend on the current consumed by the pacemaker, whether of the demand or asynchronous type. A study of the behavior of 229 mercury batteries discharged in a dry atmosphere showed that 92% of the batteries were still functioning after 54-57 months. It is deduced that pacemaker life is shortened by the infiltration of moisture into the batteries when molded in an epoxy. - A technology for the hermetic encapsulation of a pacemaker is described. This technology is applied to both mercury and lithium batteries. The results obtained with 5835 instruments over periods of up to 36 months.