Patent ID: 9572505
Date: 2017-02-21
CPC Classifications: A61B,A61N

Claim:
1. A method comprising: receiving, by sensing circuitry of an implanted medical device, a cardiac electrogram; determining, by processing circuitry, a wave marker that identifies a wave within the cardiac electrogram; determining, by the processing circuitry, a window of the cardiac electrogram around the wave marker, the window of the cardiac electrogram comprising a single wave included in the cardiac electrogram, wherein the single wave is one of a single R-wave, a single P-wave, a single T-wave, or a single QRS complex; determining, by the processing circuitry, a slope at a number of points of the cardiac electrogram within the window; determining, by the processing circuitry, a maximum value of the slope of the cardiac electrogram within the window; determining, by the processing circuitry, a threshold value based on a percentage of the maximum value of the slope, wherein determining the threshold value comprises increasing the percentage of the maximum value until the slope at one or more of the points of the cardiac electrogram within the window is less than or equal to the threshold value; and identifying, by the processing circuitry, a last point timewise of the one or more points that are less than or equal to the threshold value in the cardiac electrogram before the slope of the cardiac electrogram crosses the threshold value as one of an onset or an offset of a wave.