Segmented Ablation Cathode for Clot-Free Tissue Heating
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Solution Overview
Problem
Conventional catheter ablation techniques face challenges in creating lesions of desirable size efficiently and safely, often resulting in prolonged procedures, excessive heat generation, and the risk of blood clot formation due to inadequate cooling and power management.
Innovation Solution
An improved ablation catheter with an electrode design featuring a larger heat-exchanging portion within the catheter and a smaller portion exposed to tissue, allowing for maximum tissue contact while minimizing blood exposure, along with coolant flushing to prevent hot spots and clot formation, enabling efficient power use and reduced ablation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard electrode catheter with small exposed surface area is used for ablation, then the risk of blood clot formation is reduced, but the lesion size is insufficient and ablation efficiency is low
Solution Approach 1:
The electrode is divided into two distinct portions: a first portion with large surface area for cooling and a second portion with small surface area for ablation. This segmentation allows each portion to perform its specialized function optimally without interfering with the other.
Solution Approach 2:
Different portions of the electrode are given different surface area characteristics tailored to their specific functions. The first portion has large surface area for heat exchange with coolant, while the second portion has small surface area for efficient tissue ablation with minimal blood contact.
2Reliability
If high power RF energy is applied to create larger lesions, then the ablation effectiveness is improved, but excessive heat generation occurs causing steam pops and collateral damage
Solution Approach 1:
Coolant is supplied to the electrode before and during RF energy application to pre-cool and continuously cool the electrode. This preliminary cooling action prevents excessive temperature rise and steam pop formation while allowing effective ablation.
Solution Approach 2:
Coolant acts as an intermediary substance between the RF energy source and the tissue. It absorbs excess heat from the electrode, preventing direct transfer of excessive thermal energy to the tissue that would cause steam pops and collateral damage.
3Temperature
If the electrode is continuously cooled by blood contact, then overheating is prevented, but ablation power is lost to the blood instead of being delivered to the tissue
Solution Approach 1:
The electrode is segmented into a first portion for cooling and a second portion for ablation. This separation ensures that cooling functions do not interfere with power delivery to tissue, as the ablation portion has minimal blood contact.
Solution Approach 2:
Different portions of the electrode have different surface area characteristics optimized for their specific functions. The ablation portion has small surface area to minimize blood contact and maximize power delivery to tissue, while the cooling portion has large surface area for efficient heat exchange.
4Temperature
If a larger electrode surface area is exposed to blood for cooling, then overheating is prevented, but the risk of blood clot formation around the electrode increases
Solution Approach 1:
The electrode is divided into a first portion with large surface area for cooling and a second portion with small surface area for ablation. This segmentation concentrates blood contact to the cooling portion, minimizing thrombus formation risk at the ablation site.
Solution Approach 2:
Different portions of the electrode have different surface area characteristics. The cooling portion has large surface area for efficient heat exchange with minimal clotting risk, while the ablation portion has small surface area that minimizes blood contact and clot formation potential.
Data Source
AI summary
An ablation electrode is mounted on the distal end of a catheter with a first portion inside and a second portion outside the catheter. The second portion is adapted to have a surface that makes maximum contact with a tissue to be ablated, leaving a minimum area not covered by the tissue and potentially exposed to blood. The first portion is adapted to provide an extended surface area for efficient exchange of heat with a coolant flowing inside the catheter. Outlets provided near the area not covered by the tissue in the second portion prevents blood from getting close to or come directly in contact with the area, thereby greatly reducing formation of dangerous blood clots. The minimizing of an electrical circuit through blood greatly reduces wasted power into the electrode so that the efficiently cooled electrode is not burdened. The catheter preferably has multiple electrodes with similar features.