Multi-site Pacing Capture Detection via Evoked Response
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Solution Overview
Problem
Multi-site pacing in ambulatory medical devices complicates the optimization of electrical stimulation therapy due to the complexity of programming and detecting cardiac capture thresholds, which can lead to inefficient energy use and potential unwanted stimulation.
Innovation Solution
An apparatus with a stimulus circuit, cardiac signal sensing circuit, and control circuit that delivers electrical pulse energy to multiple pacing channels, senses cardiac depolarization, determines cardiac capture pulse energy thresholds, and identifies changes in cardiac activity morphology to distinguish between single-site and multi-site cardiac capture, providing optimized energy levels for effective therapy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-site pacing is implemented to provide electrical stimulation therapy to multiple cardiac chambers, then therapeutic effectiveness is improved, but device complexity and programming difficulty increase
Solution Approach 1:
The device performs automatic capture threshold determination for multiple pacing sites without requiring manual programming by the caregiver. The system autonomously delivers test pulses, senses evoked responses, and determines capture thresholds for each pacing channel, eliminating the need for complex manual programming while maintaining multi-site pacing effectiveness
Solution Approach 2:
The system automatically adjusts and determines optimal pulse energy levels for each pacing channel by performing capture threshold tests. This dynamic parameter determination simplifies programming by allowing the device to self-optimize stimulation parameters rather than requiring manual configuration of multiple channels
2Reliability
If capture threshold determination is performed for multiple pacing channels, then therapy optimization is improved, but energy consumption increases
Solution Approach 1:
The system performs capture threshold determination selectively rather than continuously for all channels. By determining thresholds only when needed for therapy optimization and using the determined thresholds to guide subsequent pacing delivery, the system achieves thorough therapy optimization without sustained high energy consumption
Solution Approach 2:
The device performs capture threshold determination in advance during device initialization or programming sessions. These pre-determined thresholds are then used to guide ongoing pacing therapy, reducing the need for repeated energy-intensive threshold testing during normal operation
3Reliability
If electrical pulse energy is increased to ensure cardiac capture, then capture reliability is improved, but unwanted stimulation and energy waste occur
Solution Approach 1:
The system uses evoked response sensing to provide feedback on whether cardiac capture has been achieved at each pacing site. By monitoring the sensed cardiac signals for evoked responses following pulse delivery, the system can confirm capture and adjust or reduce pulse energy levels accordingly, preventing energy waste from excessive stimulation while maintaining reliable capture
Solution Approach 2:
The device dynamically adjusts pulse energy levels based on determined capture thresholds for each pacing channel. By delivering pulses at or near the threshold level rather than using fixed high energy levels, the system maintains capture reliability while minimizing energy consumption and preventing unwanted stimulation from excessive energy delivery
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 solution simplifies the optimization of multi-site pacing by automatically determining cardiac capture thresholds, reducing energy consumption and minimizing unwanted stimulation, thereby enhancing the effectiveness and efficiency of electrical stimulation therapy.
Implementation Method 1
The stimulus circuit provides electrical pulse energy to at least a first pacing channel that includes a first left ventricular (LV) electrode as a cathode and a second pacing channel that includes a second LV electrode as a cathode
Implementation Method 2
The cardiac signal sensing circuit senses cardiac activity signals using at least a first sensing channel that includes one of the first LV electrode or the second LV electrode
Data Source
Figure 1
Figure 2A~2B
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AI summary
An apparatus comprises a stimulus circuit, a cardiac signal sensing circuit, and a control circuit. The stimulus circuit provides electrical pulse energy to a first pacing channel that includes a first left ventricular (LV) electrode as a cathode and a second pacing channel that includes a second LV electrode as a cathode. The cardiac signal sensing circuit senses cardiac signals using a first sensing channel that includes one of the first LV electrode or the second LV electrode. The control circuit includes a capture detection sub-circuit configured to: initiate delivery of electrical pulse energy to both the first pacing channel and the second pacing channel; sense cardiac depolarization of a ventricle using the first sensing channel; determine first and second cardiac capture pulse energy level thresholds for the first and second pacing channels respectively; and provide indications of the cardiac capture pulse energy level thresholds to a user or process.