A system, method, or device determines whether noise is present on a sampled
and/or
digitized sensed intrinsic cardiac signal based on a moving count of turning/inflection
points of the signal. If noise is detected, the manner in which the cardiac signal
is acquired, or the manner in which the device operates in response to the acquired
cardiac signal (or both) is altered to reduce the risk of erroneously detecting
noise as a heart depolarization and, therefore, inappropriately triggering or withholding therapy.
