Multi-site Pacing Capture Discrimination via Differential Sensing
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Solution Overview
Problem
Current cardiac pacing technologies face challenges in accurately distinguishing between single-site and multi-site capture in heart chambers, which can affect the effectiveness of cardiac resynchronization therapy for congestive heart failure, leading to variability in patient response.
Innovation Solution
A medical device with implantable electrodes and sensing circuitry that delivers pacing pulses to multiple sites within a heart chamber, generating a differential signal to discriminate between single-site and multi-site capture based on cardiac electrical activity sensed at different electrodes, allowing for adjustment of pacing energy to optimize capture status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-site pacing is used to improve coordination of heart contractions, then pumping action is improved, but the ability to accurately determine capture status deteriorates
Solution Approach 1:
The patent segments the capture detection function by using separate sensing electrodes for each pacing site. The first sensing electrode detects cardiac activity in response to the first pacing pulse, while the second sensing electrode detects cardiac activity in response to the second pacing pulse. This segmentation allows independent evaluation of capture at each site, resolving the measurement precision problem in multi-site pacing.
Solution Approach 2:
The patent introduces intermediary sensing electrodes positioned to detect cardiac electrical activity specifically at each pacing site. These intermediary sensors act as mediators between the pacing electrodes and the control system, providing distinct electrical signals that enable accurate determination of capture status at each site without interference from the other pacing site.
2Reliability
If pacing energy is increased to ensure capture, then capture reliability is improved, but battery life deteriorates
Solution Approach 1:
The patent implements feedback control by using sensing circuitry to detect cardiac electrical activity in response to each pacing pulse and determining capture status based on these detections. The control system adjusts the energy of subsequent pacing pulses based on whether capture was achieved at the previous pulse, delivering high energy only when necessary to ensure capture while using lower energy when capture is already achieved, thereby extending battery life.
3Measurement precision
If capture detection sensitivity is increased to distinguish single-site from multi-site capture, then measurement precision is improved, but device complexity deteriorates
Solution Approach 1:
The patent segments the sensing function into separate sensing electrodes and detection circuits for each pacing site. The first sensing electrode and its associated detection circuit evaluate capture at the first pacing site, while the second sensing electrode and its detection circuit evaluate capture at the second pacing site. This segmentation provides high measurement precision through independent detection without requiring complex differential analysis or signal processing.
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
The solution enables precise determination of capture status, allowing for optimized pacing energy delivery, thereby improving the coordination of heart contractions and reducing variability in patient response to cardiac resynchronization therapy.
Implementation Method 1
sensing circuitry is configured to sense cardiac electrical activity at the first and second electrodes
Data Source
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AI summary
A medical device includes pacing circuitry configured to deliver during a cardiac cycle a first pacing pulse to a first site using a first electrode as a cathode electrode for the first pacing pulse and to deliver a second pacing pulse to a second site using a second electrode as a cathode electrode for the second pacing pulse. Sensing circuitry is configured to generate a differential signal between cardiac electrical activity sensed at the first electrode and cardiac electrical activity sensed at the second electrode. Capture circuitry discriminates between single site capture and multi-site capture based on the differential signal.