Dielectric Electrode Contact Sensing for Cardiac RF Ablation
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Solution Overview
Problem
Current methods for assessing contact quality between an intra-body electrode and tissue during minimally invasive ablation procedures, such as RF ablation, rely on contact force measurements which can be indirect and require specialized probes, and do not effectively account for variations in dielectric properties that affect energy transfer during procedures like cardiac arrhythmia treatment.
Innovation Solution
A method and device that measure dielectric properties of the environment around an intra-body electrode to characterize contact quality, converting these measurements into a contact force equivalent, allowing for real-time feedback on contact sufficiency and risk of perforation, and enabling precise control of ablation parameters like power and frequency based on dielectric contact quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact force measurements are used to assess contact quality, then contact quality can be evaluated, but the method is indirect and requires specialized probes
Solution Approach 1:
The patent replaces mechanical contact force measurement systems with an electrical field-based dielectric property measurement system. The electrode measures dielectric properties of the tissue environment, which inherently provides contact quality information without requiring mechanical force sensors or specialized probe structures.
Solution Approach 2:
The patent uses dielectric properties of the tissue environment as an intermediary parameter to indirectly assess contact quality. Instead of directly measuring contact force, the system measures how the tissue's dielectric properties change in response to electrode proximity and contact, providing a reliable contact quality metric through this intermediate physical property.
2Reliability
If conventional contact assessment methods are used, then procedures can be performed, but variations in dielectric properties affecting energy transfer are not accounted for
Solution Approach 1:
The patent implements feedback by continuously measuring dielectric properties during the ablation procedure and using this information to assess contact quality and adjust treatment parameters. This real-time feedback loop ensures that variations in dielectric properties are detected and accounted for, improving the reliability of the ablation procedure.
Solution Approach 2:
The patent monitors changes in dielectric properties as a key parameter to assess contact quality and tissue response during ablation. By tracking parameter changes in the electrical characteristics of the tissue environment, the system adapts to variations in tissue composition and water content, ensuring reliable energy transfer throughout the procedure.
3Measurement precision
If dielectric property measurements are used to assess contact quality, then contact quality assessment becomes more direct and effective, but measurement and characterization complexity increases
Solution Approach 1:
The patent makes the electrode multi-functional by using it both for delivering ablation energy and for measuring dielectric properties of the tissue environment. This universal approach eliminates the need for separate measurement devices and simplifies the overall system, as the same electrode structure performs both therapeutic and diagnostic functions.
Solution Approach 2:
The system uses the electrode's own electrical field to probe the dielectric properties of the surrounding tissue environment. The measurement process is self-service in that the ablation electrode itself generates the electrical field necessary for measurement, eliminating the need for external or separate measurement systems and reducing overall measurement complexity.
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 direct and effective assessment of contact quality, improving the accuracy and safety of ablation procedures by correlating dielectric measurements with contact force, thereby enhancing the efficacy of lesion formation and reducing the risk of complications like PV reconnection in cardiac arrhythmia treatments.
Implementation Method 1
measuring dielectric properties of an environment of an electrode of an intra-body type electrode
Implementation Method 2
A high frequency alternating current (e.g., 350-500 kHz) is introduced to a treatment region through the probe, creating an electrical circuit involving tissue, which heats up as it absorbs energy of the applied electrical field
Implementation Method 3
The real part ε′r(ω) is a measure of energy stored in the material (at a given electrical field frequency and voltage), while the imaginary part ε′′r(ω) is a measure of energy dissipated. It is this dissipated energy that is converted, for example, into heat for ablation
Data Source
AI summary
Devices and methods for assessing tissue contact based on dielectric properties and/or impedance sensing are disclosed. In some embodiments, one or more probing frequencies are delivered via electrodes including an electrode in proximity to a tissue (for example, myocardial tissue). In some embodiments, dielectric parameter values, optionally together with other known and/or estimated tissue characteristics, are measured to determine a contact quality with the tissue. In some embodiments, dielectric contact quality is used, for example, in guiding the formation of a lesion (for example, RF ablation of heart tissue to alter electrical transmission characteristics).