Patent ID: 9486155
Filing Date: 2016-11-08
CPC Classification: A61B,A61N

Claim Text:
1. A method of determining a P-wave of a cardiac signal in an implantable medical device, comprising: sensing the cardiac signal; identifying one or more R-waves within the cardiac signal; determining one or more P-wave sensing windows, wherein each of the P-wave sensing window is associated with one of the one or more identified R-waves; determining a characteristic P-wave sensing window based on the one or more determined P-wave sensing windows, the characteristic P-wave sensing window having a first portion and a second portion; determining a first derivative signal of the cardiac signal within the characteristic P-wave sensing window; determining a second derivative signal of the cardiac signal within the characteristic P-wave sensing window; analyzing the first derivative and the second derivative of the cardiac signal within the characteristic P-wave window to determine a first set of signal characteristics of the cardiac signal within the first portion of the characteristic P-wave sensing window and a second set of signal characteristics of the cardiac signal within the second portion of the characteristic P-wave sensing window, the signal characteristics including zero crossings of the first derivative signal and amplitudes of the second derivative signal corresponding to the determined zero crossings; and detecting the P-wave based on the first and the second set of signal characteristics.