Patent ID: 8239020

Claim:
A cardiac rhythm management (CRM) system, comprising: a plurality of implantable subcutaneous electrodes; and an implantable medical device including: a primary sensing circuit including an electrogram sensing circuit to sense an intracardiac electrogram; an auxiliary sensing circuit coupled the plurality of implantable subcutaneous electrodes, the auxiliary sensing circuit including a wireless electrocardiogram (ECG) sensing circuit to sense a subcutaneous ECG using the plurality of implantable subcutaneous electrodes; a processing circuit having an input to receive a first signal selected from the intracardiac electrogram and the subcutaneous ECG; a switch circuit coupled to the input of the processing circuit, the switch circuit configured to receive a selection signal and to connect the input of the processing circuit to the auxiliary sensing circuit such that the subcutaneous ECG is received by the processing circuit as a substitute signal for the intracardiac electrogram in response to the selection signal; a selection circuit coupled to the switch circuit, the selection circuit configured to produce the selection signal in response to an indication of a failure mode in which the primary sensing circuit fails to provide reliable sensing of the intracardiac electrogram; a hermetically sealed can housing the primary sensing circuit, the auxiliary sensing circuit, the processing circuit, the switch circuit, and the selection circuit; and a header attached to the hermetically sealed can, wherein the plurality of implantable subcutaneous electrodes are incorporated onto one or both of the hermetically sealed can and the header.