Irrigated Ablation Catheter Fluid Flow Uniformity
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Solution Overview
Problem
Conventional irrigated ablation catheters face limitations in fluid flow efficiency due to design constraints, leading to impedance rises, hot spots, and suboptimal lesion size, with issues like uneven fluid distribution and high energy requirements for irrigation.
Innovation Solution
A catheter with a two-piece ablation tip electrode design featuring a thin outer shell and internal member, including a plenum chamber with noncircular fluid inlets and baffles, which diffuses fluid momentum for uniform distribution and reduces axial variability, enhancing fluid flow without increasing power or fluid load on the patient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional irrigation fluid flow is used in ablation catheters, then the catheter can cool the tip electrode, but fluid distribution is uneven and axial variability is high leading to hot spots and impedance rises
Solution Approach 1:
The tip electrode is divided into multiple segments with separate fluid inlets and outlets arranged in circumferential rows. This segmentation allows independent control of fluid flow to different regions, enabling uniform distribution across the entire tip surface and eliminating axial variability that causes hot spots.
Solution Approach 2:
The patent transitions from conventional single-axis fluid delivery to multi-dimensional circumferential fluid distribution. Fluid inlets and outlets are arranged in multiple circumferential rows around the tip electrode, creating radial and axial flow components that achieve uniform three-dimensional cooling distribution.
2Temperature
If higher irrigation flow rates are used to reduce hot spots, then cooling effectiveness improves, but energy consumption and fluid load on the patient increase
Solution Approach 1:
Different regions of the tip electrode are provided with dedicated fluid inlets and outlets optimized for their specific cooling requirements. The local quality of fluid delivery is enhanced by matching flow rates to the thermal needs of each segment, avoiding unnecessary energy consumption in regions that do not require high flow rates.
Solution Approach 2:
The patent maintains continuous cooling through optimized fluid circulation paths that ensure uninterrupted heat removal from the tip electrode during ablation. This continuous action prevents temperature spikes without requiring intermittent high-flow bursts, reducing overall energy consumption.
3Ease of manufacture
If conventional monolithic tip electrode design is used, then manufacturing is simpler, but fluid flow paths are inefficient and create axial variability
Solution Approach 1:
The tip electrode is segmented into multiple functional sections with dedicated fluid pathways. Each segment has its own inlet and outlet connections, allowing independent optimization of fluid flow paths. This segmentation improves flow efficiency while remaining manufacturable through modular assembly techniques.
Solution Approach 2:
The patent employs a nested structure where internal fluid pathways are integrated within the segmented tip electrode structure. The fluid channels are positioned concentrically and axially within the segmented sections, creating efficient flow paths that maximize cooling surface area contact without adding external complexity.
4Reliability
If larger fluid output area is provided in the tip electrode, then fluid distribution improves, but the diffusion ratio increases requiring more energy for irrigation
Solution Approach 1:
The patent optimizes the local quality of fluid delivery by providing fluid output areas that are specifically sized for each segment and circumferential row. This localized optimization ensures uniform distribution without creating excessive diffusion ratios, as each region receives appropriate flow rates matched to its thermal requirements.
Solution Approach 2:
The patent changes the geometric parameters of the fluid pathways, including the size, shape, and arrangement of inlets and outlets. By optimizing these parameters, the system achieves uniform fluid distribution with reduced diffusion ratios, lowering the energy required for irrigation while maintaining effective cooling.
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 design achieves more uniform and efficient fluid flow, reducing impedance rises and hot spots, allowing for larger, more spherical lesions with reduced energy consumption and fluid load, improving the effectiveness of cardiac ablation procedures.
Implementation Method 1
the cavity is designed to function as a plenum chamber by providing a variable inner cross-section so that momentum of the fluid entering the chamber is diffused and axial variability of fluid mass flow rate through the tip electrode fluid ports is reduced
Implementation Method 2
Irrigation fluid flow through the tip electrode is utilized to cool the tip electrode
Implementation Method 3
RF (radio frequency) current is applied to the tip electrode of the ablating catheter, and current flows through the media that surrounds it, i.e., blood and tissue, toward the reference electrode. Heating of the tissue occurs due to its electrical resistance
Implementation Method 4
The ablation process destroys the unwanted electrical pathways by formation of non-conducting lesions
Data Source
AI summary
An irrigated ablation catheter includes a tip electrode with a thin shell and a plug, defining a plenum chamber. The tip electrode has an inlet of a predetermined size and noncircular shape, and a predetermined number of outlet fluid ports having a predetermined diameter shell wall. The tip electrode thus considers a diffusion ratio of total fluid output area to fluid input area, and a fluid port ratio, and considers a fluid inlet aspect ratio where the fluid inlet has a noncircular radial cross-section. The plenum chamber has a narrow proximal portion opening to a wider distal portion so that fluid pressure decreases while fluid velocity increases thereby increasing turbulence which decreases momentum for a more uniform distribution of fluid in the tip electrode. Extending distally from the plug is a baffle member shaped to diffuse fluid entering the tip electrode and to house an electromagnetic position sensor.