IMPLANTATION DEVICE WITH AUTOMATIC SENSING ADJUSTMENT

摘要

An implantable cardiac pacemaker having an apparatus for sensing electrical signals in a patient's atrium and depolarizations of the patient's ventricle, wherein the apparatus for sensing electrical signals in the patient's atrium defines a base atrial sensing threshold, measures amplitudes of electrical signals sensed in the patient's atrium and responsive to sensing a depolarization of the patient's ventricle following a signal sensed in the patient's atrium defines a first increased atrial sensing threshold for a first time period thereafter, greater than the base atrial sensing threshold and based upon the measured amplitude of a previous electrical signal sensed in the patient's atrium. The sensing apparatus may further allow the increased sensing threshold to decay to the base sensing threshold following expiration of the first time period. The pacemaker may also include an apparatus for delivering pacing pulses to the patient's atrium and the sensing apparatus may also define an increased atrial sensing threshold responsive to sensing a depolarization of the patient's ventricle following a preceding delivered atrial pacing pulse.