Patent ID: 7474916

Claim:
An implantable medical device, comprising: a first sensing device positioned at a first location to generate reference signals; a second sensing device positioned at a second location different from the first location to generate monitoring signals timed relative to a detected fiducial point on the reference signals; and a microprocessor identifying cardiac events in response to the reference signals and the monitoring signals, wherein the microprocessor generates a morphology metric associated with morphology differences between the monitoring signals generated during an identified cardiac event not associated with delivery of therapy and an unidentified cardiac event, and further comprising a third sensing device positioned at a third location different from the second location to generate corresponding monitoring signals timed relative to the detected fiducial point on the reference signal, wherein the morphology metric corresponds to ((1−ρ 1 )×10) 2 +((1−ρ 2 )×10) 2 , wherein ρ 1 is a correlation coefficient associated with a monitoring signal generated by the second sensing device and ρ 2 is a correlation coefficient associated with a monitoring signal simultaneously generated by the third sensing device.