Optical Catheter Tip Sensing for Accurate Tissue Contact Force

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Solution Overview

Problem

Current catheter systems face challenges in ensuring consistent mechanical contact between the electrode and tissue during procedures, leading to potential false positive outcomes and difficulties in controlling irrigation directionality, especially in dynamic environments like the beating heart.

Innovation Solution

An optic-based catheter assembly with an optical sensor system that emits and receives optical signals transverse to the central axis of the electrode, allowing for precise measurement of contact force and orientation by sensing changes in light intensity associated with displacement, thereby enhancing contact accuracy and irrigation control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If remotely placed sensors are used to detect contact, then contact detection capability is improved, but false positive outcomes increase due to detecting catheter shaft deflection rather than actual electrode-tissue contact

Engineering Contradiction:
Improvecontact detection accuracyVSAvoidfalse positive rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The catheter is divided into functionally distinct segments: the shaft for navigation and the electrode tip for contact. The optical sensor is specifically positioned at the electrode tip rather than remotely on the shaft, enabling direct measurement of tip displacement and eliminating false positives from shaft deflection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An optical sensor serves as an intermediary measurement tool that indirectly detects electrode-tissue contact through light intensity changes caused by tip displacement. This intermediary measurement method provides more accurate contact detection compared to direct mechanical sensing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the electrode is placed in consistent mechanical contact with tissue, then procedure effectiveness is improved, but the complexity of maintaining contact in a dynamic beating heart environment increases

Engineering Contradiction:
Improveprocedure effectivenessVSAvoidcontact maintenance complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The optical sensor provides real-time feedback on electrode-tissue contact status by measuring light intensity changes. This feedback enables operators to monitor and maintain consistent contact during procedures in the dynamic beating heart environment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical contact maintenance mechanisms with an optical sensing system that uses light intensity measurements to detect and monitor contact, simplifying the overall system while improving reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If irrigation channels are added to cool the electrode tip, then thermal damage control is improved, but control over irrigation directionality becomes more difficult

Engineering Contradiction:
Improveelectrode cooling efficiencyVSAvoidirrigation directionality control
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent adds a spatial dimension to irrigation control by incorporating directional irrigation channels that can be oriented at specific angles relative to the electrode tip. This allows controlled delivery of cooling fluid in specific directions while maintaining effective thermal management.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 system reduces the likelihood of false positive contact detections and ensures precise contact force measurement, improving the efficacy and safety of procedures like ablation by providing real-time feedback on electrode-tissue interaction and directional irrigation.

Implementation Method 1

optical sensor configured to emit or receive an optical signal, at least a part of the optical signal being transverse to the central axis... sensing changes in intensity of the optical signal based on displacement associated with the tip portion of the electrode on the contact force

Methodology Applied
Scientific EffectLight intensity change: Absorption (EM radiation)

Data Source

PatentEP3372270B1Optic-based contact sensing assembly and system
Publication Date: 2021.10.06 ST JUDE MEDICAL ATRIAL FIBRILLATION DIVISION INC
  • EP3372270B1 patent drawingFigure 1~2
  • EP3372270B1 patent drawingFigure 3A~3B
  • EP3372270B1 patent drawingFigure 4

AI summary

A contact sensing assembly including a catheter and an electrode including a tip portion and a base portion, and a generally central axis, with the electrode being connected to a distal end of the catheter. Optical sensor(s) may be provided for emitting and/or receiving an optical signal, with a part of the optical signal being transverse to the central axis. Optical interference member(s) may be provided for interfering with the optical signal. A method for sensing contact force exerted by an electrode on a tissue includes directing an optical signal along a portion of a catheter, emitting and/or receiving an optical signal, with a part of the optical signal being at a predetermined angle relative to the central axis, and sensing changes in intensity of the optical signal based on displacement associated with the electrode tip portion based on the contact force exerted by the electrode on the tissue.