Patent ID: 6772009
Filing Date: 2004-08-03
Classification: A61N

Abstract:
A method for automatically adjusting a sensing threshold in a cardiac rhythm management device, comprising:sensing a ventricular electrogram signal with a ventricular sensing channel and detecting a ventricular depolarization event when the sensed ventricular signal exceeds a ventricular sensing threshold; sensing an atrial electrogram signal with an atrial sensing channel and detecting an atrial depolarization event when the sensed atrial signal exceeds an atrial sensing threshold; adjusting the sensing threshold for a sensing channel for a current cardiac cycle during a refractory period beginning with either detection of an r-wave or delivery of a ventricular pacing pulse by the device, wherein the sensing threshold is based upon a measured amplitude of a depolarization event detected through the sensing channel and a noise level measured during a post-ventricular refractory period of the current cardiac cycle; and, wherein the adjustment of the sensing threshold for a sensing channel is performed in a manner that results in a decrease of the sensing threshold for that channel if no depolarization event was detected during the current cardiac cycle in that channel and a noise level for the channel is unchanged from the previous cardiac cycle.