Rate-Responsive Pacing Noise Reduction via Beat Segmentation
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Solution Overview
Problem
Current pacing therapies struggle to accurately adjust heart rate based on patient activity levels due to noise in motion sensor readings when heart beats transition between intrinsic and pace-initiated rhythms, leading to potential over- or under-correction of heart rate.
Innovation Solution
An implantable medical device with sensors and a controller that identifies heart beats as intrinsic or pace-initiated, compares motion levels during specific phases of the cardiac cycle, and adjusts pacing rate parameters based on averaged motion levels from previous beats within a predetermined time window, while ignoring or applying offsets to account for rhythm transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If motion sensor readings are used to adjust pacing therapy, then rate-responsive pacing capability is improved, but measurement precision deteriorates due to noise during rhythm transitions
Solution Approach 1:
The patent segments the heart beat data into two distinct categories: intrinsically initiated beats and pace-initiated beats. By treating these segments separately and only comparing motion levels within the same segment, the system eliminates noise caused by rhythm transitions. This segmentation allows accurate motion-based pacing adjustments while filtering out artifacts from intrinsic-pace rhythm switching.
2Speed
If motion level comparison is performed for every heart beat, then responsiveness to activity changes is improved, but reliability deteriorates due to noise from rhythm transitions
Solution Approach 1:
The patent divides heart beats into intrinsic and pace-initiated segments, comparing motion levels only within corresponding segments. This maintains responsiveness by continuously monitoring motion while ensuring reliability by excluding noisy transition points from the comparison calculation.
Solution Approach 2:
The patent converts the harmful effect of rhythm transitions (which cause noise in motion readings) into a useful classification feature. By identifying and separating intrinsic beats from pace-initiated beats, the system uses the rhythm transition information itself to guide the comparison process, turning a source of error into a structural element that improves measurement accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces noise in activity level measurements, leading to more accurate adjustments in pacing therapy, ensuring heart rate is appropriately elevated or maintained according to the patient's activity level, thereby improving the effectiveness of rate-responsive pacing.
Implementation Method 1
a motion sensor (e.g. accelerometer) during the systole phase of the intrinsically initiated heart beat
Data Source
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AI summary
Systems, devices, and methods for pacing a heart of a patient are disclosed. An illustrative method may include determining a motion level of the patient using a motion sensor of an implantable medical device secured relative to a patient's heart, and setting a pacing rate based at least in part on the patient's motion level. The patient's motion level may be determined by, for example, comparing the motion level sensed by the motion sensor during a current heart beat to a motion level associated with one or more previous heart beats. Noise may occur in the motion level measurements during those heart beats that transition between an intrinsically initiated heart beat and pace initiated heart beat. Various techniques may be applied to the motion level measurements to help reduce the effect of such noise.