Cross-Chamber Cardiac Capture Detection
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Solution Overview
Problem
Current cardiac rhythm management systems face challenges in accurately determining capture threshold for pacing pulses, leading to inefficient energy management and potential discomfort or battery life issues, as they struggle to reliably produce heart contractions without excessive energy expenditure.
Innovation Solution
The method involves delivering pacing pulses to both heart chambers and sensing for a propagating cardiac response to determine capture, using a capture detection circuit to adjust pulse energy and ensure optimal contraction without wasting energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pacing pulse energy is increased to ensure capture, then capture reliability is improved, but energy expenditure increases and battery life decreases
Solution Approach 1:
The system continuously monitors the heart chamber response to pacing pulses and uses this feedback to determine whether capture occurred. Based on the feedback, the system adjusts the pacing pulse energy level, increasing it only when capture is lost and decreasing it when capture is achieved, thereby optimizing energy expenditure while maintaining capture reliability.
Solution Approach 2:
The system dynamically changes the energy parameter of pacing pulses based on captured responses. When capture is detected, the system reduces pulse energy to the minimum effective level. When capture is lost, the system increases pulse energy. This parameter adjustment continues throughout operation to balance capture reliability with energy conservation.
2Use of energy by moving object
If pacing pulse energy is decreased to conserve battery life, then energy expenditure is reduced, but capture reliability may be compromised
Solution Approach 1:
The system uses feedback from capturing detection to verify whether reduced energy levels are sufficient for reliable capture. If the monitoring indicates that capture is achieved at lower energy levels, the system maintains these reduced levels to conserve battery life. If capture is lost, the system automatically increases energy levels to restore reliability.
Solution Approach 2:
The system transitions from static, fixed energy levels to dynamic, adaptive energy adjustment. Pacing pulse energy is continuously modified based on real-time capture status, allowing the system to operate at minimum effective energy when capture is reliable and to increase energy only when necessary to maintain capture reliability.
3Productivity
If capture detection is performed continuously to optimize energy management, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The capture detection circuit performs multiple functions: it monitors pacing pulse effectiveness, determines capture status, triggers backup pulses when needed, and provides data for energy level adjustment. By making this single circuit multi-functional, the system avoids adding separate complex systems for each function, thereby improving energy efficiency without proportionally increasing device complexity.
Solution Approach 2:
The system combines the capture detection function with the existing pacing and monitoring circuits. Rather than adding a completely separate detection system, the detection capability is integrated into the pulse generator architecture, sharing components such as the sensing electrodes and signal processing circuits, thus reducing overall device complexity while achieving continuous energy-efficient operation.
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 allows for efficient energy management by ensuring that pacing pulses achieve capture while minimizing energy expenditure, thereby enhancing cardiac rhythm management and prolonging device battery life.
Implementation Method 1
A pacing pulse that causes a sufficient depolarization of the myocardium, producing a propagating wave of excitation produces a contraction
Implementation Method 2
The captured response may include an electrical signal, denoted the evoked response signal, associated with the heart contraction
Implementation Method 3
The magnitude of the residual post pace polarization signal, or pacing artifact, may be affected by a variety of factors including lead polarization
Data Source
AI summary
Methods and systems involve multi-chamber cardiac capture detection utilizing sensing during a cross-chamber refractory period. First and second pacing pulses are delivered to first and second heart chamber. Capture or non-capture of the second heart chamber is determined. Sensing in the first heart chamber is performed to sense for cross-chamber propagation initiated by the second pacing pulse. Capture of the first chamber is detected if capture of the second heart chamber is detected and if the cross-chamber propagation is not detected.