Ablation Catheter Contact Force Prediction for Isolation Line Gaps

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Solution Overview

Problem

Catheter-based contact ablation techniques for atrial fibrillation face challenges in predicting lesion formation and preventing post-operative recurrence due to electrical reconnection across isolation lines, particularly in the left anterior wall, where stable contact is difficult to achieve, leading to higher incidence of isolation gaps.

Innovation Solution

A device and method that predict lesion size and integrity using a 'lesion size index' (LSI) based on contact force, energization parameters, and duration, and a 'jump index' (JI) to track the sequential formation of lesions, enhancing the prediction of isolation line continuity and reducing gap formation by dynamically determining subsequent contact points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If point contact ablation is used to create isolation lines, then the procedure is minimally invasive and faster, but the predictability of lesion formation is poor and isolation gaps are more common

Engineering Contradiction:
Improveablation procedure speedVSAvoidlesion formation predictability
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements real-time feedback by measuring contact force during ablation and using it to predict lesion size. The system continuously monitors the force applied by the catheter to the tissue and adjusts or alerts the operator to maintain optimal contact force, ensuring predictable lesion formation while maintaining the speed of point contact ablation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces subjective mechanical assessment (operator judgment of contact stability) with objective mechanical measurement (force sensor readings). By substituting the mechanical sensing system with electronic force measurement, the patent achieves both rapid ablation and predictable lesion formation through quantifiable data

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

2Manufacturing precision

If continuous monitoring of contact force is implemented, then lesion size predictability improves, but device complexity increases

Engineering Contradiction:
Improvelesion size prediction accuracyVSAvoidcatheter system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a force sensor as an intermediary element between the catheter and tissue. This sensor acts as a mediator that translates mechanical contact into electrical signals that can be processed and used for prediction, adding minimal complexity while significantly improving lesion size predictability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter being monitored from qualitative (operator assessment) to quantitative (force magnitude in grams). By measuring and utilizing specific force parameter ranges (e.g., 5-20 grams optimal contact), the system achieves accurate lesion prediction without excessive complexity

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If electrical continuity measurements are performed frequently to detect isolation gaps, then detection accuracy improves, but procedure time increases

Engineering Contradiction:
Improveisolation gap detection accuracyVSAvoidprocedure time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary action by predicting lesion size and identifying potential isolation gaps before they occur. By using contact force data to anticipate where gaps might form, the system can take preventive measures during ablation rather than performing multiple post-hoc continuity measurements, saving time while maintaining high detection accuracy

Inventive Principle:
Principle #10Preliminary action

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 solution effectively predicts lesion size and continuity, reducing the occurrence of post-operative gaps and improving the long-term success of isolation lines by providing real-time feedback and optimizing the ablation process.

Implementation Method 1

The ablation head is energized to create a lesion on and within the target tissue

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

Catheter-based contact ablation techniques involve the ablation of groups of cells... Methods of energy delivery include radiofrequency

Methodology Applied
Scientific EffectRadiofrequency ablation:

Implementation Method 3

the catheter including a distal portion having an ablation head operatively coupled with a force sensor

Methodology Applied
Scientific EffectForce sensing:

Data Source

PatentEP3482708B1Prediction of atrial wall electrical reconnection based on contact force measured duing RF ablation
Publication Date: 2021.03.10 ST JUDE MEDICAL INT HLDG SARL
  • EP3482708B1 patent drawingFigure 1~3
  • EP3482708B1 patent drawingFigure 4A~4F
  • EP3482708B1 patent drawingFigure 5~6D

AI summary

A system for forming an isolation line with a series of point contact lesions, comprising means for forming a plurality of lesions by point contact ablation, and means for determining the continuity of the isolation line formed by the plurality of lesions is disclosed. And a method for determining the continuity of an isolation line in a region of a human heart is disclosed, comprising configuring a processor to receive data from a position sensing device during the forming of a plurality of lesions, the received data being indicative of a sensed location of the plurality of lesions substantially along a desired ablation line, determine if a jump occurred between each consecutively formed pair of lesions of said plurality of lesions, said jump being defined by a predetermined criteria of spatial separation between said consecutively formed pairs of lesions, and increment a jump index for each jump detected in the formation of said plurality of lesions along the desired ablation line, and determine a probability of gap formation along said isolation line based on said jump index and force data associated with each of said consecutively formed pairs of lesions.