Microfabricated Catheter Tip Temperature Sensor

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Solution Overview

Problem

Current catheters lack accurate and real-time temperature measurement capabilities at the distal tip, leading to impedance rises and limitations in lesion size during cardiac ablation procedures due to incomplete cooling and potential for tissue charring.

Innovation Solution

Integration of a microfabricated thin film temperature sensor on the outer surface of the catheter tip, utilizing thermoresistive material to measure interfacial temperature with multiple sensor layers and lead wires for precise signal communication, enabling real-time monitoring of tissue and catheter tip temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature monitoring is not implemented, then the ablation procedure can proceed without additional device complexity, but impedance rises occur and lesion size is limited due to uncontrolled heating

Engineering Contradiction:

Improvetemperature control reliabilityVSAvoidcatheter device complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The temperature sensor is integrated directly into the catheter tip structure, merging the sensing function with the existing ablation device. This integration approach reduces overall system complexity while enabling reliable temperature monitoring at the treatment site.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The catheter tip is designed to perform multiple functions: RF energy delivery for ablation, temperature sensing through the integrated sensor, and irrigation for cooling. This multi-functionality allows temperature control without requiring a separate dedicated sensing device.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Temperature

If passive cooling by blood circulation is used, then no additional cooling system is needed, but temperature control is insufficient leading to tissue charring and impedance rises

Engineering Contradiction:

Improvecatheter tip temperatureVSAvoidtissue charring and coagulation

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The integrated temperature sensor provides real-time feedback on catheter tip temperature, enabling the control system to adjust RF power delivery dynamically. This feedback mechanism prevents temperature from rising to levels that cause tissue charring and impedance increases.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The temperature sensor is positioned to detect temperature changes before they reach harmful levels. By monitoring temperature in advance, the system can reduce RF power before tissue charring or coagulum formation occurs, preventing these harmful effects.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If temperature sensor is integrated on catheter tip, then real-time temperature measurement is achieved, but manufacturing complexity increases due to microfabrication requirements

Engineering Contradiction:

Improvetemperature measurement precisionVSAvoidcatheter manufacturing ease

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The mechanical temperature sensing approach is replaced with a microfabricated thin film sensor that can be deposited directly onto the catheter tip substrate. This substitution enables precise temperature measurement while using standard semiconductor manufacturing techniques rather than complex mechanical assembly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

A thin film temperature sensor is used instead of bulk temperature sensing elements. The thin film structure can be conformally deposited on the catheter tip surface, providing accurate temperature measurement while maintaining flexibility and compatibility with standard manufacturing processes.

Inventive Principle:

Principle #30Flexible shells and thin films

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 temperature control during procedures, reducing the risk of coagulation and tissue charring, allowing for larger and more controlled lesion creation while minimizing impedance rises and improving overall catheter performance.

Implementation Method 1

The temperature sensor includes a microfabricated thin film assembly of which one layer is a sensor layer of thermoresistive material

Methodology Applied

Scientific EffectThermoresistive effect: Thermo-resistive Effect

Implementation Method 2

Heating of the tissue occurs due to its electrical resistance. The tissue is heated sufficiently to cause cellular destruction in the cardiac tissue resulting in formation of a lesion within the cardiac tissue which is electrically non-conductive.

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 3

In a typical application of RF current to the endocardium, circulating blood provides some cooling of the ablation electrode.

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS8034050B2Catheter with microfabricated temperature sensing

Publication Date: 2011.10.11 BIOSENSE WEBSTER INC

AI summary

A catheter with temperature sensing has a catheter body and a tip section with an integrated thermosistive temperature sensor on its outer surface. The temperature sensor includes a microfabricated thin film assembly of which one layer is a sensor layer of thermoresistive material. In one embodiment, the tip section has a flexible tubing with a temperature sensor on its outer surface. In another embodiment, the tip section has an extended tip electrode with a temperature sensor on its outer surface.