초록 ▼

In using electrogram signals to determine physiologic conditions like ischemia, the bad cardiac cycle information due to noise, axis shifts in the cardiac electrical axis, and the like must be removed if the electrogram signal can be made to be a good indicator. If this is accomplished through the a

In using electrogram signals to determine physiologic conditions like ischemia, the bad cardiac cycle information due to noise, axis shifts in the cardiac electrical axis, and the like must be removed if the electrogram signal can be made to be a good indicator. If this is accomplished through the adaptive filtering techniques shown here, the signal can be used to drive a closed loop therapy system responsive to those physiologic conditions discernible from good cardiac cycle electrocardiogram signals.

대표청구항 ▼

[ What is claimed is:] [1.] A method for filtering out information from invalid or undesirable cardiac cycle signals in a series of cardiac cycle signals present in a cardiac electrogram signal to eliminate consideration of information from said invalid cycle in evaluating said cardiac electrogram s

[ What is claimed is:] [1.] A method for filtering out information from invalid or undesirable cardiac cycle signals in a series of cardiac cycle signals present in a cardiac electrogram signal to eliminate consideration of information from said invalid cycle in evaluating said cardiac electrogram signal, said method employing adaptive amplitude thresholds and comprising a cycle repeated for each cardiac cycle, comprising the steps:a) for a given cardiac cycle, collecting a selected set of characteristic portions of the electrocardiogram signal and sampling specific point locations within said portions, and thereby measuring the electrocardiogram amplitude at said specific sampled point locations and producing measured values for each point location,b) parameterizing each said sampled selected set of portions by calculating a plurality of characteristic parameter values based on said measured values of said point locations in said set of portions collected in step a for said given cardiac cycle,c) employing a plurality of previously calculated expected value ranges, one said range for each characteristic parameter value from step b, to determine whether each said parameter value of said plurality of characteristic parameter values is within said previously calculated expected range for said each parameter,d) determining cardiac cycle validity for said given cardiac cycle from which said set of portions was collected in step a, based on a determination that a predetermined sufficient number of said plurality of parameters for a cardiac cycle are within said ranges, ande) if said given cardiac cycle is determined to have been valid, then, updating by recalculating said previously calculated expected ranges based on the characteristic parameter values determined in step b so as to provide flexibility to said adaptive amplitude thresholds and to provide data to adjust said ranges.