IMPLANTABLE SENSORS HAVING HIGH IMPEDANCE COUPLINGS PROVIDING CURRENT PATHWAYS FOR IMPROVED FAULT TOLERANCE

One aspect of the invention involves a possible fault scenario due to a breach of an inner layer of insulation of an elongated medical electrical lead which couples an active electrical circuit for an active implantable medical device (AIMD)-typically within a conductive AIMD housing-to a sensor disposed within a sensor capsule. In one form, the AIMD provides physiological sensing of a patient parameter, such as endocardial pressure via a chronically implanted absolute pressure sensor. In such a physiological monitor, a high impedance connection is established between the active electrical circuit and the conductive AIMD housing. In a therapy delivering AIMD, a high impedance connection is established between therapy electrodes and the active electrical circuit. As a result, any errant electrical current(s) will be shunted directly to the reference-ground of the sensor-bearing lead in lieu of traveling through a patient's tissue or conductive body fluid.