A system for adaptively processing patient monitoring signals comprises an input processor for acquiring a signal having amplitude representing electrical activity of a patient heart over time. A signal processor identifies different portions of the signal associated with different phases of cardiac activity by, inverting the signal to provide an inverted signal, aligning the signal and the inverted signal in amplitude during a cardiac rest portion and identifying one or more of the different portions in response to an intersection point of the signal and the inverted signal. Multiple adaptive signal filters are used to filter multiple bandwidths of corresponding different portions of the signal.
