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Abstract

Disclosed are systems and methods for detecting the QRS portion of an electrocardiogram and also for detect QRS onset/offset points. QRS complexes are identified by testing selected waveform samples to determine if they are in a high curvature region. If a region passes the high curvature test, a verification test is applied to adjacent samples to confirm that the region is within a QRS complex. The search for a QRS onset point begins at an adaptive distance from this region. The curvature of selected regions ahead in the search direction is examined. The search moves past all such high curvature regions. The onset point is then located by searching for a region that is “flat” in either of two senses. First, a region may be locally flat (i.e. small first derivative) in an absolute sense. Second, a region is flat in a relative that further movement away from the interior of the QRS (e.g. toward “earlier” samples) does not result in a significant change in the value of the first derivative. The search is performed by hopping through the waveform samples. Once an onset point is located, the search for an offset point proceeds in a similar manner from a starting point that is an adaptively determined distance from the onset point.

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First Claim