Intelligent telemetric implants

Abstract

All today's active implantable medical devices utilize wireless telemetry, serving at least one of the two purposes: Power transmission and/or communication with an extra corporal unit. For implant powering, three strategies are widely used: 1. Primary (non-rechargeable) batteries, that require the presence of a system providing information on battery condition, warning the user/practitioner of an upcoming battery exhaustion. Usually, the implementation of such a system employs a telemetric data link. 2. Inductive coupling, using an extra corporal transmitter coil generating an alternating magnetic field, which couples through the skin into an implanted receiver coil that converts the magnetic flux into an electrical supply voltage. 3. Secondary batteries that are periodically recharged using an inductive link. Here, a power monitoring system is mandatory, commonly implemented by a telemetric link. Besides the telemetric links associated with power supply and its monitoring, implants communicate with extra-corporal units in order to transmit recorded physiological data, to report implant malfunction or critical conditions, to be re-programmed (e.g. adaptation of stimulation intensity in pacemakers), or in future applications, to communicate with other implants within a bodyinternal wireless network. © 2012 by Walter de Gruyter Berlin Boston.