Intracardiac Impedance for CRT Parameter Optimization
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Solution Overview
Problem
Current methods for optimizing cardiac resynchronization therapy (CRT) parameters, such as AV and VV delays, are subjective and exhibit high variability, with existing automated systems lacking precision in using echocardiography for optimization.
Innovation Solution
An implantable medical device that utilizes intracardiac impedance signals in combination with heart sounds to optimize CRT parameters by monitoring temporal fiducial points during the cardiac cycle, extracting measurements, and determining selection data for optimal pacing configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If echocardiography is used for CRT optimization, then automated selection of AV and VV delays is achieved, but measurement precision is reduced due to high intra- and inter-individual variability
Solution Approach 1:
The patent replaces echocardiography (ultrasound-based mechanical imaging system) with electrical impedance sensing. The impedance sensor detects changes in electrical impedance across the heart during different phases of the cardiac cycle, providing a different physical modality for measuring cardiac function that is less susceptible to the variability problems of echocardiography.
Solution Approach 2:
The patent changes the measurement parameter from mechanical/ultrasound-based echocardiographic measurements to electrical impedance measurements. By monitoring impedance variations during systole and diastole, the system derives cardiac function parameters that enable more precise and reproducible CRT optimization compared to echocardiography.
2Ease of operation
If echocardiography optimization is used, then CRT parameters can be adjusted, but device complexity increases due to subjectivity and variability requiring clinician intervention
Solution Approach 1:
The patent enables the implantable device to automatically perform optimization without requiring external echocardiography equipment or clinician interpretation. The device self-measures impedance, self-processes the signals to determine cardiac function parameters, and self-adjusts CRT parameters based on the measured data, eliminating the need for complex external systems and subjective clinician judgment.
Solution Approach 2:
The patent implements a closed-loop feedback system where the implantable device continuously monitors impedance, compares measurements against optimal ranges, and automatically adjusts pacing parameters in real-time. This feedback mechanism simplifies operation by eliminating manual intervention while maintaining precise control over CRT 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 approach provides a more precise and individualized optimization of CRT parameters, improving cardiac function and reducing variability, leading to enhanced therapeutic efficacy for patients with heart failure.
Implementation Method 1
a sensing module configured to monitor at least an intracardiac impedance between at least two electrodes to provide an intracardiac impedance signal
Data Source
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AI summary
Methods and/or devices used in delivering cardiac resynchronization therapy based on a plurality of device parameters (e.g., A-V delay, V-V delay, etc.) are optimized by setting a device parameter based on selection data. The selection data may be acquired by acquiring temporal fiducial points (e.g., heart sounds) associated with at least a part of a systolic portion of at least one cardiac cycle and/or temporal fiducial points associated with at least a part of a diastolic portion of the at least one cardiac cycle for each of a plurality of electrode vector configurations, and extracting measurements from the intracardiac impedance signal acquired for each of a plurality of electrode vector configurations based on the temporal fiducial points. The acquired selection data may be scored and used to optimize the device parameter.