Tip Electrode Flow Directing Member for Irrigated Catheter Cooling
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Solution Overview
Problem
Current irrigated ablation catheters suffer from non-uniform fluid distribution across the tip electrode, leading to incomplete cooling and increased thrombus formation due to direct blood contact, which limits the effectiveness of RF energy application and lesion size.
Innovation Solution
An irrigated ablation catheter design featuring an axially directed flow of irrigation fluid, directed by a thin-walled tubular flow directing member around the tip electrode, ensuring a uniform boundary layer and enhanced convective heat loss through the outer surface, reducing blood contact and protein denaturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If holes are placed in specific locations around the tip electrode to distribute irrigation fluid, then fluid distribution is provided, but uniform fluid distribution along the outer surface of the tip electrode is not achieved
Solution Approach 1:
A flow directing member is introduced as an intermediary component between the irrigation fluid source and the tip electrode. This member actively directs and shapes the fluid flow to wrap around the tip electrode, ensuring uniform distribution along its outer surface rather than relying on passive hole placement.
Solution Approach 2:
The invention changes the flow parameters of the irrigation fluid by using a flow directing member to control velocity, direction, and distribution pattern. This transforms the fluid delivery from discrete holes to a continuous, uniform wraparound flow pattern that maintains consistent contact with the electrode surface.
2Area of stationary object
If irrigation fluid is projected far from the tip electrode, then cooling coverage is extended, but a uniform and complete boundary layer from the surrounding blood is not provided
Solution Approach 1:
The flow directing member creates locally optimized fluid flow characteristics by ensuring the irrigation fluid closely follows and wraps around the contour of the tip electrode. This local adaptation of flow pattern to electrode geometry maintains a stable, uniform boundary layer right at the electrode surface where it is most needed for cooling and thrombus prevention.
3Power
If RF current strength is increased without irrigation, then larger lesions can be created, but electrode heating increases causing char and thrombus formation
Solution Approach 1:
The flow directing member is positioned to deliver irrigation fluid to the tip electrode surface before and during RF energy application. This preliminary cooling action prevents electrode heating and thrombus formation, allowing higher RF power to be applied safely without causing harmful effects.
4Reliability
If a stagnant area forms between the electrode and tissue, then protein coating forms on the electrode surface, but effective cooling and flushing is reduced
Solution Approach 1:
The flow directing member creates a continuous flow of irrigation fluid that constantly wraps around the tip electrode, preventing stagnant areas from forming. This continuous flushing action maintains electrode surface cleanliness and sustains effective cooling throughout the ablation procedure, allowing prolonged operation without thrombus formation.
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 improved fluid distribution and convective heat transfer result in larger, more efficient lesions with reduced thrombus formation, allowing for increased power delivery during RF ablation while maintaining effective cooling of the tip electrode.
Implementation Method 1
the tip electrode is cooled by the flow of saline through it and the surface of the electrode is flushed... improved convective cooling of the tip electrode and tissue-to-tip electrode interface
Implementation Method 2
provide an irrigated catheter with a generally complete and uniform boundary layer reducing direct blood contact with the tip electrode during the application of RF energy
Implementation Method 3
Heating of the tissue occurs due to its electrical resistance. The tissue is heated sufficiently to cause a lesion
Data Source
AI summary
An irrigated ablation catheter provides improved distribution of irrigation fluid across its tip electrode surface resulting in improved cooling and flushing of blood and proteins from the tip region. An axially directed flow of irrigation provides improved heat transfer from the tip electrode to the irrigation fluid allowing for a cooler tip electrode and larger lesions. The irrigation fluid is introduced to the catheter with improved flow by means of a standard constant flow pump. A lumen or tube within a shaft of the catheter transfers the irrigation fluid to a proximal end of the tip electrode where it exits the catheter via a flow directing member mounted on the tip electrode. In one embodiment, the flow directing member is a thin walled tube that surrounds the proximal end of the tip electrode and directs the irrigation fluid distally along an outer surface of the tip electrode.