Ablation Catheter Contact Force Feedback for Isolation Line Continuity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

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 ablation duration, and track the sequential nature of lesion formation using a jump index (JI) to enhance the continuity and predictability of the isolation line, allowing for real-time adjustments during the procedure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If point contact ablation is used to create isolation lines, then the procedure is less invasive and has shorter recuperation time, but stable contact force is difficult to maintain leading to isolation gaps

Engineering Contradiction:

Improveminimally invasive accessVSAvoidisolation line continuity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system incorporates a force sensor that provides real-time feedback on contact force between the ablation catheter and tissue. This feedback loop allows the operator to maintain stable contact force throughout the ablation procedure, preventing isolation gaps while preserving the minimally invasive nature of point contact ablation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system monitors and adjusts ablation parameters (power, duration, contact force) in real-time to optimize lesion formation. By dynamically changing these parameters based on actual contact conditions, the system ensures reliable isolation line creation while maintaining the benefits of catheter-based access.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If contact force is increased to improve lesion formation, then ablation effectiveness increases, but risk of tissue damage and procedure complexity increases

Engineering Contradiction:

Improvelesion formation precisionVSAvoidcontact force control system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical force application mechanisms with a simpler force sensor-based monitoring system. Instead of using complex mechanisms to apply and control force, the system uses a force sensor to detect contact force and provides feedback to guide the operator in maintaining appropriate force levels.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If multiple continuity measurements are taken to predict isolation gaps, then prediction accuracy improves, but procedure time and operational complexity increase

Engineering Contradiction:

Improveisolation gap prediction accuracyVSAvoidprocedure time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary monitoring of contact force during the ablation procedure itself, rather than requiring separate post-procedure continuity measurements. By measuring contact force in real-time during ablation, the system predicts isolation gap formation without adding extra measurement steps or extending procedure time.

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 significantly improves the predictability and effectiveness of forming continuous isolation lines, reducing the occurrence of post-operative gaps and enhancing long-term success rates by providing a statistically significant increase in the absence of gaps within three months after ablation.

Implementation Method 1

Methods of energy delivery include radiofrequency, microwave, cryothermy, laser, and high intensity ultrasound. The probe is then placed in contact with the posterior wall of the left atrium and energized to locally ablate the tissue

Methodology Applied

Scientific EffectRadiofrequency heating: Dielectric Heating

Implementation Method 2

the size of a lesion is predicted on the basis of the contact force between the ablation head and a target tissue

Methodology Applied

Scientific EffectForce sensing:

Data Source

PatentUS9149327B2Prediction of atrial wall electrical reconnection based on contact force measured during RF ablation

Publication Date: 2015.10.06 ST JUDE MEDICAL INT HLDG SARL

AI summary

A method and device for determining the transmuriality and/or continuity of an isolation line formed by a plurality of point contact ablations. In one embodiment, a method for determining the size of a lesion (width, depth and/or volume) is disclosed, based on contact force of the ablation head with the target tissue, and an energization parameter that quantifies the energy delivered to the target tissue during the duration time of the lesion formation. In another embodiment, the sequential nature (sequence in time and space) of the ablation line formation is tracked and quantified in a quantity herein referred to as the “jump index,” and used in conjunction with the lesion size information to determine the probability of a gap later forming in the isolation line.