RF Transseptal Needle Perforation with Impedance Feedback
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Solution Overview
Problem
Current transseptal perforation procedures face challenges such as complications from RF ablation due to tissue overheating and the risk of life-threatening complications from improper needle puncture, particularly in patients lacking a patent foramen ovale.
Innovation Solution
A transseptal needle equipped with magnetic field sensors and electrodes that monitor impedance changes to control RF ablation, automatically terminating energy delivery when predetermined impedance differences or time limits are reached, ensuring precise tissue contact and perforation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RF current is applied to ablate tissue during transseptal perforation, then tissue heating and ablation efficiency are improved, but tissue overheating and complications such as steam pop, charring, and thrombosis occur
Solution Approach 1:
The system continuously monitors electrical impedance during RF ablation and uses this feedback to control the ablation process. When impedance changes indicate tissue overheating or complete perforation, the system automatically adjusts or terminates energy delivery, preventing steam pop, charring, and thrombosis while maintaining efficient ablation
Solution Approach 2:
The system dynamically changes RF energy parameters (power, duration, frequency) based on real-time impedance measurements. By adjusting these parameters in response to tissue conditions, the system optimizes ablation efficiency while preventing overheating and associated complications
2Length of moving object
If high voltage or extended ablation time is used to increase heating through ablated tissue, then ablation penetration is improved, but overheating of blood and adjacent structures increases
Solution Approach 1:
Real-time impedance monitoring provides feedback on the ablation zone and surrounding tissue conditions. When impedance changes suggest proximity to blood vessels or adjacent structures, the system reduces power or terminates ablation, preventing overheating of blood and surrounding tissues while achieving adequate penetration
Solution Approach 2:
The system applies RF energy in controlled pulses rather than continuous high power, delivering partial energy increments that accumulate to achieve penetration without excessive heating of adjacent structures. This staged approach allows tissue to conduct heat away between pulses
3Speed
If transseptal perforation is performed without precise control, then procedural speed is improved, but life-threatening complications from improper needle puncture increase
Solution Approach 1:
The system provides real-time feedback through impedance monitoring and magnetic field sensor tracking to guide needle advancement. This feedback enables operators to perform perforation quickly while maintaining high safety standards by immediately detecting proper tissue contact and perforation completion
Solution Approach 2:
The patent replaces manual mechanical needle guidance with electromagnetic field-based positioning using magnetic field sensors. This substitution provides more precise and reliable needle location tracking, improving both speed and safety of the puncture procedure
4Measurement precision
If magnetic field sensors and impedance monitoring are added to the transseptal needle, then perforation precision and safety are improved, but device complexity increases
Solution Approach 1:
The patent combines magnetic field sensors, electrodes, and control electronics into an integrated transseptal needle assembly. This merging of components into a single unified device provides precise measurement capabilities while minimizing the complexity of having separate systems, as all functions are coordinated through a single control unit
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 ensures safe and precise transseptal perforation by preventing tissue overheating and reducing complications, providing real-time feedback on perforation status.
Implementation Method 1
The transseptal needle can include one or more magnetic field sensors configured to provide location information of a distal end of the transseptal needle
Implementation Method 2
The electrodes can be disposed proximate the distal end and can be configured to measure impedance indicative of tissue contact
Implementation Method 3
The application of RF current to biological tissue causes heating of the tissue. The higher the RF current density in the biological tissue (current per unit area), the higher the resulting temperature
Implementation Method 4
As tissue is ablated, impedance of the tissue increases, thereby decreasing the current density through the tissue for a given voltage
Data Source
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AI summary
An example RF ablation system including a transseptal needle having an ablation electrode thereon can be used to perform a transseptal perforation using RF energy. Ablation energy can be applied and/or terminated based on a change in impedance at the ablation electrode when the electrode come into or out of contact with tissue. The transseptal needle can further include magnetic field sensors and one or more electrodes. The magnetic field sensors can be positioned approximate a distal end of the transseptal needle and can be configured to provide location information of the distal end.