Patent ID: 7164950
Filing Date: 2007-01-16
Classification: A61N

Abstract:
1. An implantable cardiac device comprising: internal circuitry; a housing that encases the internal circuitry; a conductor connected to the internal circuitry; an isolation system comprising: a sensor unit that detects a presence of a magnetic field; at least one non-filtered feedthrough that prevents a current induction loop from forming between the conductor and the housing; at least one filtered feedthrough disposed within the housing and that protects the internal circuitry; and a switch bank disposed inside the housing, between the non-filtered feedthrough and the filtered feedthrough, and connected to the sensor unit, to selectively disconnect an electrical conduction path from the conductor to the internal circuitry, upon sensing the presence of a predetermined magnetic field by the sensor unit; a controller disposed within the housing, that is coupled to the sensor unit, and that operatively controls the switch bank; wherein the sensor unit comprises a magnetic field sensor; wherein the sensor unit further comprises a tunable radio frequency sensor that further detects the presence of a radio frequency signal; wherein the sensor unit detects the presence of any of the magnetic field or the radio frequency signal continuously; and wherein if the magnetic field sensor detects a presence of a high-Tesla magnetic field, the controller initiates a voltage sweep to adjust the tunable radio frequency sensor to match the radio frequency of the detected high-Tesla magnetic field.