Intracardiac Electrogram Catheter Electrode Selection for Far-Field Signals
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Solution Overview
Problem
Conventional catheters with planar distal end assemblies for measuring heart tissue electrical properties lack a specific electrode for reliably sensing far-field intracardiac-electrogram (IEGM) signals, leading to inconsistent and inaccurate measurements.
Innovation Solution
A reference electrode on the catheter shaft is used to measure impedance with distal end electrodes, dynamically selecting electrodes sufficiently distant from the heart tissue to determine the far-field IEGM component by averaging their signals, and subtracting this from near-field components to obtain accurate cardiac tissue activation signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional catheters with planar distal end assemblies are used, then fabrication costs are reduced, but measurement precision of far-field IEGM signals deteriorates due to lack of dedicated electrode
Solution Approach 1:
The patent applies multi-functionality by enabling distal end electrodes to serve dual purposes: both near-field tissue contact sensing and far-field signal sensing when sufficiently distant from tissue. The system dynamically selects electrodes based on their distance from tissue, allowing the same electrode array to function for both near-field and far-field measurements without requiring separate dedicated electrodes.
Solution Approach 2:
The system uses the catheter's own distal end electrodes to generate the far-field signal through dynamic selection and averaging, rather than requiring an external or separate reference electrode. The electrodes serve themselves by being selectively used for far-field measurement when not in contact with tissue.
2Measurement precision
If volumetric distal end assemblies with multiple splines are used, then far-field IEGM signal measurement is improved through dedicated electrode placement, but device complexity and fabrication cost increase
Solution Approach 1:
The patent extracts the far-field sensing function from the traditional volumetric basket structure and implements it using the planar distal end electrode array through dynamic selection. This removes the need for complex three-dimensional spline structures while maintaining far-field measurement capability.
Solution Approach 2:
Instead of using a complex volumetric structure to achieve far-field sensing, the patent inverts the approach by using a simple planar structure and achieving far-field capability through signal processing and dynamic electrode selection based on tissue distance.
3Ease of manufacture
If planar distal end assembly is used, then fabrication cost is reduced, but reliability of far-field signal measurement deteriorates due to inconsistent electrode-tissue distance
Solution Approach 1:
The patent applies dynamics by continuously monitoring tissue distance for each electrode and dynamically selecting which electrodes to use for far-field signal generation. This dynamic adaptation ensures that only electrodes at appropriate distances from tissue are used, maintaining measurement reliability despite the simplicity of the planar structure.
Solution Approach 2:
The system uses feedback from tissue proximity measurements to control the selection of electrodes for far-field signal generation. The real-time distance information feeds back into the signal processing algorithm to determine which electrodes should contribute to the far-field signal, ensuring consistent and reliable measurements.
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 method enables accurate measurement of far-field IEGM signals without a dedicated electrode, reducing fabrication costs and improving the reliability of cardiac tissue activation signal determination.
Implementation Method 1
A reference electrode on the catheter shaft is used to measure impedance with distal end electrodes
Data Source
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AI summary
Method and system to determine cardiac tissue activation signals are disclosed. The method provides to inter-alia determine a far-field component of Intracardiac Electrogram (IEGM) signal sensed by at least one electrode of a plurality of electrodes of a catheter. The method includes applying tissue proximity measurement to each respective electrode of a multitude of the catheter's electrodes to assess respective distances thereof respectively from a tissue surface; dynamically selecting, based on the respective distances, a subset of one or more electrodes of the multitude whose respective distances from the tissue surface are above a certain threshold; and determining a far-field component of the IEGM signal by averaging IEGM signal measurements from the electrodes of the subset whose respective distances are above the certain threshold.