Balloon Ablation Electrode Contact Detection by Blood Temperature Sensing
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Solution Overview
Problem
Existing medical probes, such as cardiac RF balloon ablation catheters, face challenges in accurately determining whether ablation electrodes are in good physical contact with tissue, particularly at locations like the pulmonary vein ostium, often relying on tedious methods like fluoroscopy which are not precise for identifying incomplete contact.
Innovation Solution
A system and method using an expandable balloon catheter with multiple electrodes and sensors that measure blood characteristics via fluid injection, allowing a processor to determine electrode-tissue contact based on transient changes in properties like temperature or impedance, providing real-time touch indication without the need for X-ray fluoroscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluoroscopy is used to determine electrode-tissue contact, then positioning accuracy can be achieved, but patient exposure to harmful radiation increases and the process becomes more complex
Solution Approach 1:
The patent replaces the mechanical/optical fluoroscopy system with a thermal sensing system. Temperature sensors detect temperature changes in blood near the electrode, and processor logic determines contact status based on these thermal measurements, eliminating the need for ionizing radiation while maintaining contact detection accuracy
Solution Approach 2:
The patent uses blood temperature as an intermediary parameter to infer electrode-tissue contact. Instead of directly imaging the contact interface, the system measures temperature changes in the blood caused by RF energy transfer, which serves as an indirect but reliable indicator of contact quality
2Measurement precision
If fluoroscopy is used to assess electrode contact, then positioning information can be obtained, but device complexity and procedural time increase
Solution Approach 1:
The complex fluoroscopy imaging system is replaced with a simple thermal measurement system. Temperature sensors and processor logic provide contact detection without the need for X-ray generators, detectors, and complex image processing, significantly reducing device complexity
Solution Approach 2:
The system changes the measurement parameter from optical/radiological properties to thermal properties. By measuring temperature changes in blood rather than using imaging, the system achieves contact detection with simpler, more direct measurements that reduce procedural complexity
3Ease of operation
If traditional temperature sensing is used without fluid flow, then measurement simplicity is maintained, but measurement precision deteriorates due to insufficient transient response
Solution Approach 1:
The system uses periodic or controlled fluid flow through the catheter to create transient temperature changes. By introducing fluid flow that causes periodic or controlled thermal variations, the system generates the dynamic response needed for accurate contact detection while maintaining operational simplicity
Solution Approach 2:
The system performs preliminary fluid flow to establish baseline temperature conditions before making contact determinations. This preliminary action ensures that the measurement environment is properly conditioned, improving precision without adding complex measurement procedures
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
Enhances the accuracy of balloon catheter positioning against tissue, improving the effectiveness of ablation treatments by ensuring complete electrode-tissue contact, and reducing the need for harmful fluoroscopy imaging.
Implementation Method 1
one or more temperature sensors in proximity to each electrode... each temperature sensor to measure a resulting temperature in proximity to the electrode
Implementation Method 2
injecting a coolant fluid... measuring, via the one or more temperature sensors, a dependence of the characteristic of blood on time
Data Source
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AI summary
A method includes positioning an expandable balloon, coupled to a distal end of a catheter, at a target location within an organ of a patient, the expandable balloon including multiple electrodes and one or more sensors in proximity to each electrode, wherein the one or more sensors are configured each to measure a characteristic of blood. The expandable balloon is expanded at the target location. A fluid is flowed through an inner lumen of the catheter and into the blood in a vicinity of each electrode. A dependence of the characteristic of blood on time is measured, via the one or more sensors, in proximity to each electrode. Using a processor, it is determined whether or not each electrode is in physical contact with tissue, based on the measured dependence of the characteristic of blood. An indication of whether or not each electrode is in physical contact with tissue is outputted to a user.