Cardiac pacer energy conservation system

Abstract

A system for extending the lifetime of an implantable cardiac pacer of the type having an internal primary battery power source includes an external energy transmitting source for selectively externally powering the pacer in order to reduce consumption of the internal battery power. While the pacer is operating on external power, current drain from the internal primary battery is reduced substantially to zero, thus extending useful battery life. The external energy source may include an electromagnetic energy transmitting coil, which transmits energy to an implanted energy receiving coil, the received energy being then rectified, filtered, and used to power the pacer. If a large-diameter energy transmitting coil is employed, the transmitting and receiving coils may be loosely coupled to provide a more convenient and easy-to-use energy conservation system. Alternatively, the external energy source may comprise a radio-frequency source, and transmitted radio-frequency energy may be received by an internal antenna which may comprise the cardiac pacing lead electrode system. The energy conservation system may also be provided with a secondary or rechargeable battery of lower energy capacity than that of the primary battery, which secondary battery may be repeatedly recharged from the external energy source to further extend the life of the primary source. In order to stabilize and reduce system current drain, a series-type voltage regulator may be provided between the primary battery and the pacer circuitry.