Catheter Tip Electrode Fluid Flow and Force Sensing
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Solution Overview
Problem
Current catheter designs for ablation procedures lack efficient mechanisms for heat exchange and force measurement during tissue ablation, which can lead to suboptimal ablation efficacy and safety due to inadequate fluid distribution and force regulation.
Innovation Solution
The catheter incorporates a tip electrode with microelectrode apertures and a printed circuit board (PCB) for signal acquisition, thermally isolated microelectrodes for temperature measurement, and a slotted tube with strain gauges to estimate force applied during ablation, along with fluid apertures for efficient heat exchange and fluid flow through a narrow space between the PCB and the tip electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple dedicated irrigation tubings are used to supply fluid to respective electrodes, then fluid delivery to different electrodes at different flow rates is improved, but device complexity increases
Solution Approach 1:
The single irrigation lumen serves multiple functions: it delivers irrigation fluid to the tip electrode, provides a pathway for the PCB assembly, and enables thermal management. This multi-functional design eliminates the need for separate dedicated tubings for each electrode while maintaining the capability to deliver fluid at controlled rates.
Solution Approach 2:
The irrigation fluid pathway and the electronic signal pathway are merged within the same catheter structure. The PCB is positioned within the irrigation lumen, combining the fluid delivery function and electrical signal acquisition function into a single integrated system rather than requiring separate tubings.
2Volume of moving object
If the PCB is positioned within the irrigation lumen, then space utilization is improved, but fluid flow pathway restriction may occur
Solution Approach 1:
The PCB is positioned in the proximal portion of the irrigation lumen, leaving the distal portion of the lumen completely open for unrestricted fluid flow. This localized positioning strategy allows the PCB to occupy only the space it needs while preserving adequate fluid pathway dimensions downstream.
Solution Approach 2:
The PCB is oriented perpendicular to the longitudinal axis of the catheter, extending radially within the lumen rather than longitudinally. This dimensional reorientation allows the PCB to utilize the radial space of the lumen while minimizing obstruction to the longitudinal fluid flow pathway.
3Measurement precision
If microelectrodes are thermally isolated from the tip electrode, then temperature measurement accuracy is improved, but heat exchange efficiency may be reduced
Solution Approach 1:
The microelectrodes are positioned within microelectrode apertures in the tip electrode, using the aperture walls as a thermal intermediary. The thin aperture walls provide sufficient thermal isolation for accurate temperature measurement while still allowing proximity to the tissue for effective heat exchange during ablation.
Solution Approach 2:
The tip electrode is segmented with multiple microelectrode apertures that create discrete thermal zones. Each aperture provides a localized measurement point that is thermally isolated from the main electrode body, enabling independent temperature monitoring at multiple locations without compromising the overall heat exchange function of the tip electrode.
4Measurement precision
If strain gauges are integrated into the catheter structure, then force measurement capability is improved, but device complexity increases
Solution Approach 1:
The catheter structure is designed to serve multiple functions: it delivers ablation energy, provides irrigation fluid flow, and measures contact force through integrated strain gauges. This multi-functional integration eliminates the need for separate force measurement devices while maintaining all essential ablation capabilities.
Solution Approach 2:
The strain gauge measurement system is merged with the catheter's structural framework. The strain gauges are attached to load-bearing components of the catheter, combining the mechanical support function with the force sensing function into a single integrated system.
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 design enhances heat exchange efficiency, prevents blood clots, and accurately measures forces applied to the tissue, improving the safety and efficacy of the ablation procedure by ensuring secure electrode attachment and precise force regulation.
Implementation Method 1
A plurality of strain gauges are coupled to the bridges, and are configured to output signals in response to bending of the bridges
Implementation Method 2
Temperature sensors coupled to the PCB, each of the temperature sensors being thermally coupled to the conducting element of a respective one of the microelectrodes
Implementation Method 3
fluid apertures for efficient heat exchange and fluid flow through a narrow space between the PCB and the tip electrode
Data Source
Figure 1
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AI summary
Described embodiments include apparatus that includes a catheter and a tip electrode, at a distal end of the catheter, shaped to define a plurality of fluid apertures. A structure, within the tip electrode, is configured such that fluid passed distally through a lumen of the catheter flows in a longitudinal direction through a space between the structure and an inner surface of the tip electrode, prior to exiting through the fluid apertures. Other embodiments are also described.