PFA Catheter Impedance Path Control for Consistent Lesions
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Solution Overview
Problem
Existing pulsed field ablation (PFA) systems face challenges in accurately delivering electric fields to patient tissue due to complex impedance paths, leading to inconsistent lesion formation and potential collateral damage.
Innovation Solution
A method and system for determining and adjusting excitation voltages and input resistances in a PFA system by considering tissue and parasitic impedances, using a catheter electrode distribution system (CEDS) to optimize electric field delivery, allowing for variable impedance paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional PFA systems deliver electric fields using fixed impedance paths, then the system structure is simple, but the lesion formation is inconsistent and collateral damage occurs
Solution Approach 1:
The patent implements dynamic impedance control by allowing the system to adjust circuit path configurations and excitation voltages in real-time based on measured tissue impedance characteristics. The CEDS dynamically reconfigures connections between electrodes and generator outputs to optimize electric field delivery for each specific tissue target, transforming a static system into an adaptive one that responds to varying tissue properties.
Solution Approach 2:
The system changes multiple parameters simultaneously including excitation voltage amplitude, circuit path configuration, and electrode selection based on measured tissue impedance. By measuring tissue impedance first and then adjusting these parameters accordingly, the system achieves consistent lesion formation across different tissue types and locations, resolving the contradiction between precision and complexity.
2Reliability
If higher excitation voltages are applied to overcome parasitic impedance, then electric field delivery is improved, but energy loss and potential tissue damage increase
Solution Approach 1:
The patent applies local quality by delivering electric fields selectively to specific tissue regions through carefully chosen circuit paths and electrode configurations. By measuring tissue impedance and identifying optimal circuit paths, the system concentrates energy precisely where needed while minimizing exposure of surrounding healthy tissue to high voltages, thus reducing collateral damage while maintaining reliable field delivery to the target.
Solution Approach 2:
The system uses measured tissue impedance as an intermediary parameter to mediate between the generator output and the target tissue. By measuring impedance first and using this information to adjust excitation voltages and select circuit paths, the system acts as an intelligent intermediary that prevents excessive energy delivery, thereby avoiding tissue damage while ensuring sufficient energy reaches the target.
3Adaptability or versatility
If multiple circuit paths are available for electric field delivery, then versatility and adaptability improve, but determining optimal paths becomes more complex
Solution Approach 1:
The patent applies preliminary action by measuring tissue impedance and determining optimal circuit paths before delivering the therapeutic electric field. The system performs preliminary measurements of impedance characteristics for multiple potential circuit paths, selects the最优 configuration, and then proceeds with treatment. This preliminary characterization simplifies the subsequent delivery phase and enables adaptability without overwhelming complexity during active treatment.
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
Enhances the precision and consistency of electric field delivery, reducing collateral tissue damage and improving lesion formation control.
Implementation Method 1
Electroporation is the application of an electric field to cells in order to increase the permeability of the cell membrane. Pulsed field ablation (PFA) which can cause reversible or irreversible electroporation
Implementation Method 2
a desired voltage between the two electrodes; a tissue impedance between the two electrodes; and a parasitic impedance associated with the circuit path
Data Source
AI summary
A method and pulsed field ablation (PFA) system configured to provide variable impedance paths for delivery of electric fields to patient tissue using a PFA catheter are disclosed. According to one aspect, a method includes determining a current for each of a plurality of circuit paths, each circuit path including two electrodes. Each current may be determined based at least in part on: a desired voltage between the two electrodes; a tissue impedance between the two electrodes; and a parasitic impedance associated with the circuit path. The method also includes determining at least one of an excitation voltage and an input resistance for each circuit path of the plurality of circuit paths based at least in part on the determined current for the circuit path, parasitic impedances associated with the circuit path and a tissue impedance between the two electrodes in the circuit path.