Electrode Catheter Impedance Measurement for Tissue Contact
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Solution Overview
Problem
Existing electrode catheters for tissue ablation face challenges in ensuring adequate tissue contact and electrical coupling, leading to inefficient lesion formation and potential complications such as inadequate lesions, high impedance shut-off, tissue charring, and thrombus formation, due to the lack of reliable methods for determining electrode-tissue contact and electrical coupling.
Innovation Solution
An electrode catheter system with a measurement circuit to assess impedance between the electrode and ground, using reactance and phase angle measurements to determine contact and coupling conditions, allowing for real-time feedback to the user to adjust the electrode position for optimal contact and coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional techniques such as fluoroscopy are used to determine electrode-tissue contact, then the physician can visualize the electrode position, but the actual contact and electrical coupling cannot be reliably determined
Solution Approach 1:
The patent replaces mechanical/visual inspection methods (fluoroscopy) with electrical measurement methods. A measurement circuit applies test signals to the electrode and measures electrical properties (impedance, phase angle, reactance) to detect electrode-tissue contact and electrical coupling, substituting visual observation with electrical sensing.
Solution Approach 2:
The patent introduces electrical measurements (impedance, phase angle, reactance) as intermediary parameters to indirectly assess electrode-tissue contact. These electrical properties serve as mediators that correlate with contact quality without requiring direct visual observation of the tissue-electrode interface.
2Ease of operation
If the physician uses generalized pre-determined ablation parameters based on experience, then the procedure can be performed without real-time contact assessment, but inadequate lesion formation, high impedance shut-off, tissue charring, and thrombus formation may occur
Solution Approach 1:
The patent implements real-time feedback by continuously monitoring electrical properties (impedance, phase angle, reactance) during ablation and using this information to assess electrode-tissue contact quality. This feedback enables the physician to adjust ablation parameters dynamically based on actual contact conditions rather than relying on predetermined settings.
Solution Approach 2:
The patent performs preliminary assessment of electrode-tissue contact using electrical measurements before initiating ablation. By evaluating impedance, phase angle, and reactance in advance, the system determines whether adequate contact exists before applying ablative energy, preventing complications from inadequate contact assessment.
3Device complexity
If the electrode catheter lacks real-time contact assessment capability, then the device structure remains simple, but adequate tissue contact and electrical coupling cannot be ensured
Solution Approach 1:
The patent integrates multiple functions into the electrode catheter system: the measurement circuit uses the same electrode to both deliver ablation energy and assess contact quality. The system performs dual functions (ablation and contact assessment) using shared components, minimizing additional hardware complexity while enabling precise contact measurement.
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
The system enables precise control of electrode-tissue contact and electrical coupling, improving the formation of consistent lesions while reducing the risk of complications by providing real-time feedback for optimal energy application.
Implementation Method 1
A measurement circuit adapted to measure impedance may be implemented between the electrode and ground as the electrode approaches a target tissue
Implementation Method 2
A processor or processing units may be implemented to determine a contact condition for the target tissue based at least in part on reactance of the impedance measured by the measurement circuit
Implementation Method 3
In another embodiment, the contact condition may be based on the phase angle of the impedance
Implementation Method 4
Although radio frequency (RF) ablative energy is predominately resistive heating at typical operating frequencies of about 500 kHz
Data Source
AI summary
An electrode catheter and a method for assessing electrode-tissue contact and coupling are disclosed. An exemplary electrode catheter comprises an electrode adapted to apply electrical energy. A measurement circuit is adapted to measure impedance between the electrode and ground as the electrode approaches a target tissue. A processor determines a contact and coupling condition for the target tissue based at least in part on reactance of the impedance measured by the measurement circuit. In another exemplary embodiment, the electrode catheter determines the contact and coupling condition based at least in part on a phase angle of the impedance.