Patent ID: 8560055

Claim:
A cardiac monitor for estimating a value of a heart signal parameter, the monitor comprising: (a) a sensor for sensing an analog signal from a human heart; (b) a device coupled to the sensor, the device having analog-to-digital circuit system contained therein for digitizing the analog signal to produce a digitized waveform; and (c) a processor electrically coupled to the analog-to-digital circuit system, the processor configured to: (i) analyze the waveform to detect a plurality of beats; (ii) determine which of the plurality of beats meet analyzable beat criteria; (iii) determine a relative frequency of beats that meet the analyzable beat criteria; (iv) based on the relative frequency, determine whether to update a time series that tracks the value of a heart signal parameter; (v) operative when the time series is to be updated, updating the time series based on the output of a recursive filter, the filter having a first input that is based on a current value of the time series, the filter having a second input that is based on a current value of the heart signal parameter associated with a beat that meets the analyzable beat criteria.