Mini-Electrode Catheter for Precise Tissue Impedance Measurement
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Solution Overview
Problem
Current medical devices for tissue diagnosis and ablation, such as catheters, face challenges in precisely locating targeted tissue due to the size and spacing of electrodes, which can lead to inaccurate electrical measurements and potential damage to healthy tissue.
Innovation Solution
The use of mini-electrodes in conjunction with ablation and ring electrodes in a four-terminal sensing configuration allows for precise measurement of tissue proximity and contact, enabling accurate impedance measurements and reducing the risk of damaging healthy tissue by concentrating current delivery to localized areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electrodes are used in catheters for tissue diagnosis and ablation, then the device structure is simple and easy to manufacture, but the measurement precision of tissue proximity and contact is insufficient, leading to inaccurate electrical measurements and potential damage to healthy tissue
Solution Approach 1:
The catheter incorporates multiple mini-electrodes (first sensing electrode, second sensing electrode, third sensing electrode) distributed along the shaft, with each electrode serving specific measurement functions. This segmentation of sensing functions across multiple small electrodes enables precise tissue proximity detection while maintaining manageable device complexity through modular electrode placement
Solution Approach 2:
The mini-electrodes are disposed on or near the ablation electrode structure, with sensing electrodes positioned at different distances from the distal tip. This nested arrangement allows multiple sensing functions to be integrated within the overall catheter structure, improving measurement precision without proportionally increasing device complexity
2Power
If larger electrodes are used to ensure adequate current delivery for ablation, then the ablation effectiveness is improved, but the risk of damaging surrounding healthy tissue increases due to current spread
Solution Approach 1:
The catheter employs mini-electrodes with small surface areas positioned at specific locations along the shaft, including near the distal tip and at intermediate positions. This local concentration of current delivery capability allows effective ablation at the target site while minimizing current spread to surrounding healthy tissue, achieving high power delivery where needed without increasing harmful effects
Solution Approach 2:
The multiple sensing electrodes measure impedance values that provide feedback on tissue proximity and contact status. This feedback mechanism allows real-time adjustment of current delivery parameters, ensuring adequate power for ablation when tissue contact is confirmed while preventing excessive current delivery that could damage healthy tissue
3Measurement precision
If mini-electrodes are used to improve measurement precision and localize current delivery, then tissue proximity assessment accuracy is enhanced and healthy tissue protection is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Multiple sensing electrodes and the ablation electrode are integrated into a single catheter shaft structure, with electrodes disposed at predetermined positions along the shaft. This merging of multiple electrode functions into one unified device improves measurement precision through coordinated sensing while simplifying manufacturing compared to using separate devices for each function
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 configuration enhances the accuracy of tissue proximity assessment and ablation procedures by minimizing the impact of electrode impedance on measurement results and allowing for precise positioning of electrodes near the target tissue, thereby improving the effectiveness of ablation therapy while protecting surrounding healthy tissue.
Implementation Method 1
determine an impedance value based on the measured potential difference and the injected current
Implementation Method 2
one or more current-carrying electrodes and one or more sensing electrodes includes an ablation electrode
Data Source
AI summary
Medical devices and methods for making and using medical devices are disclosed. An example electrophysiology medical device may include a catheter shaft including a distal end portion and a sensing assembly having three or more terminals. The sensing assembly includes one or more current-carrying electrodes and one or more sensing electrodes. The one or more current-carrying electrodes, the one or more sensing electrodes, or both includes a mini-electrode. The mini-electrode is disposed on one of the other electrodes. The medical device may also include a controller coupled to the sensing assembly.