Patent ID: 8265756
Filing Date: 2012-09-11
Classification: A61N

Abstract:
1. A method for use by an implantable medical device capable of automatically adjusting a sensitivity with which electrical cardiac signals are sensed within a patient, the method comprising: sensing electrical cardiac signals within the patient while adjusting the sensitivity during individual cardiac cycles in accordance with a sensitivity adjustment procedure specified by a plurality of sensitivity adjustment parameters including, at least, a Decay Rate and one or more of a Starting Sensitivity parameter specifying a Starting Sensitivity for use following detection of a sensed event, a Decay Delay parameter specifying a duration of time during an individual cardiac cycle following the sensed event before sensitivity is automatically decreased, a Refractory Interval specifying a duration of time during an individual cardiac cycle following a sensed event during which any further events are not sensed, wherein the Decay Rate specifies a rate by which the sensitivity is changed during an individual cardiac cycle following completion of the Decay Delay; detecting depolarization and repolarization event parameters within the electrical cardiac signals, including depolarization event amplitudes, depolarization event widths and repolarization event amplitudes; determining a set of comparisons by comparing each of the detected parameters to a corresponding nominal value of the parameter to determine if the detected parameter is at its nominal value, larger than its nominal value or smaller than its nominal value; and resetting the sensitivity adjustment parameters, including selectively resetting the Decay Rate and one or more of the Starting Sensitivity, the Decay Delay and the Refractory Interval, based on the set of comparisons wherein, if the depolarization amplitude is larger than its nominal value, the depolarization width is at its nominal value and the repolarization amplitude is smaller than its nominal value, then the adjustment parameters are maintained at nominal values.