Electrode-Tissue Coupling Index via Impedance Standardization
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Solution Overview
Problem
Current methods for assessing the degree of coupling between medical device electrodes and tissue, such as cardiac tissue, are inadequate due to reliance on clinician experience, radiation exposure, time-consuming procedures, and high rates of false positives/negatives, and do not accurately measure electrical coupling.
Innovation Solution
A system and method that calculates a coupling index based on complex impedance components like resistance and reactance between the electrode and tissue, standardized to account for variations in patient and system parameters, providing a clear and interpretable measure of tissue contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods like fluoroscopic imaging or clinician sense are used to assess electrode-tissue coupling, then the procedure can be performed with existing equipment, but the measurement precision and reliability are insufficient due to radiation exposure, subjectivity, and high rates of false positives/negatives
Solution Approach 1:
The patent replaces mechanical and radiological assessment methods (fluoroscopic imaging, tactile feedback) with an electrical field-based impedance measurement system. The system uses electrical signals to detect coupling status, eliminating radiation exposure and subjective clinician assessment while providing objective, real-time feedback through calculated coupling indices.
Solution Approach 2:
The patent introduces impedance as an intermediary parameter to assess electrode-tissue coupling. Instead of directly observing physical contact or tissue damage, the system measures electrical impedance changes that occur when the electrode approaches or contacts tissue, providing an indirect but accurate indicator of coupling status that correlates with actual tissue interaction.
2Measurement precision
If complex impedance measurements are performed to accurately assess coupling, then measurement precision improves, but device complexity and computational requirements increase
Solution Approach 1:
The patent segments the complex impedance measurement into distinct components (resistive and reactive parts) that can be independently measured and analyzed. This segmentation allows the system to process different aspects of the impedance separately, simplifying the computational approach while maintaining measurement precision.
Solution Approach 2:
The system uses the existing electrical field and measurement capabilities already present in ablation systems to perform impedance measurements. The same electrodes and signal generation circuits used for ablation therapy also serve for coupling assessment, eliminating the need for separate dedicated measurement hardware and reducing overall system complexity.
3Reliability
If real-time coupling assessment is implemented to improve safety and effectiveness, then procedural safety improves, but the time required for measurements and calculations increases
Solution Approach 1:
The patent implements continuous or near-continuous impedance measurements throughout the ablation procedure, providing real-time coupling assessment. The system continuously monitors impedance changes as the catheter moves and as tissue properties change during ablation, enabling dynamic adjustment of ablation parameters to maintain safety and effectiveness throughout the entire procedure.
Solution Approach 2:
The system performs preliminary impedance measurements during the approach phase to predict upcoming tissue contact and potential coupling issues before they occur. This allows the system to prepare appropriate responses in advance, such as adjusting ablation power settings or alerting the operator, thereby preventing safety issues rather than merely detecting them after they arise.
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 offers a reliable and efficient assessment of electrode-tissue coupling, improving the safety and effectiveness of medical procedures by accurately measuring energy delivery and proximity, reducing complications, and enhancing geometric modeling of tissue surfaces.
Implementation Method 1
an electronic control unit to acquire values for first and second components of a complex impedance between the electrode and the tissue
Data Source
AI summary
A system and method for assessing a degree of coupling between an electrode and tissue in a body is provided. Values for first and second components of a complex impedance (e.g., resistance and reactance or impedance magnitude and phase angle) between the electrode and the tissue are obtained. These values are used together with a standardization value indicative of a deviation from a reference standard by a parameter associated with at least one of the body, the electrode and another component of the system to calculate a coupling index that is indicative of a degree of coupling between the electrode and the tissue. The coupling index may be displayed to a clinician in a variety of ways to indicate the degree of coupling to the clinician. The system and method find particular application in ablation of tissue by permitting a clinician to create lesions in the tissue more effectively and safely.