Open-Irrigated Catheter Tip Segmented Cooling Ports
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Solution Overview
Problem
Open-irrigated RF ablation catheters face challenges such as excessive heating of the proximal electrode portion due to edge effects and current density concentrations, which can lead to current loss or excessive tissue heating, despite efforts to mitigate these issues through modifications in irrigation port sizes and distributions.
Innovation Solution
The design incorporates smaller proximal irrigation ports ('micro-holes') in conjunction with larger distal irrigation ports, ensuring effective cooling fluid flow to the proximal electrode while maintaining desired current pathways, using a hybrid catheter configuration for both mapping and ablation with a deflectable tip and integrated mapping electrodes for precise ECG signal recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If larger irrigation ports are used to improve cooling efficiency, then cooling effectiveness improves, but current loss and excessive tissue heating occur due to edge effects and current density concentrations
Solution Approach 1:
The irrigation system is segmented into multiple small proximal ports and fewer large distal ports. This segmentation allows the proximal region to receive adequate cooling through numerous small openings while maintaining proper current pathways, as the small ports do not create significant edge effects or current density concentrations that would cause current loss or excessive heating.
Solution Approach 2:
Different regions of the catheter tip receive different port configurations tailored to their specific needs. The proximal region, which experiences edge effects, is equipped with multiple small irrigation ports for effective cooling without compromising current pathways. The distal region uses larger ports for primary cooling function. This local differentiation resolves the contradiction by optimizing each region's cooling approach according to its electrical and thermal characteristics.
2Temperature
If proximal irrigation ports are added to cool the proximal electrode portion, then temperature control improves, but device complexity increases
Solution Approach 1:
The proximal and distal irrigation systems are merged into a single integrated catheter structure with unified fluid delivery mechanisms. The proximal ports are integrated into the electrode assembly itself, while distal ports are incorporated into the catheter body, creating a cohesive cooling system that manages proximal temperature control without requiring separate complex subsystems.
3Temperature
If multiple rows of proximal irrigation ports are used to enhance cooling coverage, then temperature uniformity improves, but manufacturing precision requirements increase
Solution Approach 1:
The proximal irrigation ports are arranged in an asymmetric pattern with two rows at different radial positions rather than symmetric uniform distribution. The first row is positioned at a first radial distance from the central axis, and the second row at a second radial distance, creating asymmetric cooling coverage that achieves temperature uniformity while being more tolerant to manufacturing variations in port placement.
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 effectively controls temperature, reduces coagulum formation, prevents impedance rise, and maximizes energy transfer to the tissue, enabling more precise ablation procedures by maintaining current pathways and minimizing adverse heating effects.
Implementation Method 1
a cooling fluid is delivered through the catheter to a tip assembly having a tissue ablation electrode, where the fluid exits through irrigation ports defined in the tissue ablation electrode to cool the electrode
Implementation Method 2
the exterior wall is conductive for delivering radio frequency (RF) energy for an RF ablation procedure
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An open-irrigated catheter system includes a catheter body and a tip assembly, coupled to a distal end of the catheter body. The tip assembly includes an exterior wall that is conductive for delivering radio frequency (RF) energy for an RF ablation procedure, and that defines an interior region. The exterior wall includes a number of proximal irrigation ports and a number of distal irrigation ports. At least one fluid chamber is defined within the interior region and is in fluid communication with at least one of the proximal irrigation ports and the distal irrigation ports. At least one fluid lumen extends from a fluid source, through the catheter body, to the tip assembly, and is in fluid communication with the at least one fluid chamber.