Implantable cardiac device sensing with refractory period alignment to signal peak
AssigneeCameron Health, Inc.
InventorsRick Sanghera, Venugopal Allavatam, Mark Schroeder
Life of this patent
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Abstract
Methods and devices for addressing difficulty with cardiac event sensing that can arise if the starting point of the cardiac cycle is not well aligned to the intended starting point of a detection profile used for sensing. As an improvement, illustrative methods and devices provide an addition to cardiac sensing operations by adjusting the starting point of a detection profile to align with a desired point in the cardiac signal.
Claims20
A method of detecting QRS complexes in an implantable medical device system, the implantable medical device system comprising at least two electrodes for sensing cardiac activity coupled, electrically, to operational circuitry for analyzing sensed cardiac activity, the method comprising the operational circuitry:
- applying a time-changing detection threshold to a sensed signal until the sensed signal crosses the detection threshold, wherein the detection threshold includes a first time period during which the operational circuitry will not detect an event, and at least a second time period after the first time period during which the operational circuitry will detect an event upon crossing of the detection threshold by a sensed signal;
- declaring a first detected event in association with the sensed signal crossing the detection threshold;
- identifying a peak during a seeking interval that includes the point in time when the sensed signal crossed the detection threshold leading to the first detected event;
- and
- re-applying the time-changing detection threshold such that the first time period begins at a time corresponding to the identified peak.
A method of detecting QRS complexes in an implantable medical device system, the implantable medical device system comprising at least two electrodes for sensing cardiac activity coupled, electrically, to operational circuitry for analyzing sensed cardiac activity, the method comprising the operational circuitry:
- applying a time-changing detection threshold to a sensed signal until the sensed signal crosses the detection threshold, wherein the detection threshold includes a first time period during which the operational circuitry will not detect an event, and at least a second time period after the first time period during which the operational circuitry will detect an event upon crossing of the detection threshold by a sensed signal;
- declaring a first detected event in association with the sensed signal crossing the detection threshold at a first point in time;
- identifying a second point in time relative to the first detected event;
- re-applying the time-changing detection threshold such that the first time period begins at the second point in time,
- wherein the second point in time and the first point in time are not simultaneous.
An implantable medical device system comprising at least two electrodes for sensing cardiac activity coupled, electrically, to operational circuitry for analyzing sensed cardiac activity, the operational circuitry being configured to identify QRS complexes of a sensed signal captured using the electrodes by the following:
- the operational circuitry comparing a time-changing detection threshold to the sensed signal captured from the electrodes, until the sensed signal crosses the detection threshold, wherein the detection threshold includes a first time period during which the operational circuitry will not detect an event, and at least a second time period after the first time period during which the operational circuitry will detect an event upon crossing of the detection threshold by a sensed signal;
- the operational circuitry declaring a first detected event in association with the sensed signal crossing the detection threshold at a first point in time;
- the operational circuitry identifying a second point in time relative to the first detected event;
- the operational circuitry re-applying the time-changing detection threshold such that the first time period begins at the second point in time,
- the operational circuitry being configured such that the second point in time and the first point in time are not simultaneous.
Dependencies are inferred from the claim text.