Catheter Force Sensor for Real-Time Ablation Volume Control

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Solution Overview

Problem

Current methods for intracardiac radio-frequency ablation lack effective real-time monitoring and control of electrode contact force and energy application, leading to inconsistent tissue ablation and potential tissue damage.

Innovation Solution

A method and apparatus that measure mechanical force between a catheter and cardiac tissue, using this force to adjust RF power and application time for precise control of ablation volume, with real-time visualization and monitoring of the ablation process to ensure optimal tissue treatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RF energy is applied to ablate cardiac tissue, then therapeutic effect is achieved, but excessive tissue damage may occur without proper contact control

Engineering Contradiction:
Improvetherapeutic effectVSAvoidexcessive tissue damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements real-time feedback by measuring contact force between the catheter electrode and cardiac tissue using a force sensor, and using this measurement to dynamically adjust RF power delivery. The system continuously monitors contact force and modulates energy application accordingly, preventing excessive tissue damage while ensuring adequate ablation when proper contact is maintained.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the RF power parameter dynamically based on contact force measurements. When contact force exceeds a threshold indicating proper tissue contact, the system increases or maintains RF power for effective ablation. When contact force is below the threshold, the system reduces or stops power delivery to prevent harmful effects from inadequate contact, thus optimizing the therapeutic window.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If contact pressure is increased to ensure proper electrode-tissue contact, then ablation effectiveness improves, but risk of excessive tissue damage increases

Engineering Contradiction:
Improveablation precisionVSAvoidtissue damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The system uses real-time contact force feedback to precisely control the relationship between contact pressure and ablation outcome. By measuring actual contact force and adjusting RF power accordingly, the system achieves precise ablation when proper contact is made while automatically preventing damage when contact is excessive or insufficient, eliminating the need for manual pressure estimation by the operator.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If real-time monitoring of contact force is implemented, then ablation control improves, but device complexity increases

Engineering Contradiction:
Improvecontact force measurementVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical pressure measurement systems with a force sensor that directly measures contact force between the electrode and tissue. This sensor integrates into the catheter structure and provides electrical signals that can be processed by the existing RF control system, achieving precise contact force measurement without requiring overly complex mechanical sensing mechanisms.

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

4Productivity

If RF power is increased to accelerate ablation, then treatment time decreases, but tissue damage control becomes more difficult

Engineering Contradiction:
Improveablation rateVSAvoidtissue damage control
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic RF power delivery that adjusts in real-time based on contact force measurements. The system can rapidly increase power when proper contact is detected to achieve fast ablation, and immediately reduce or stop power when contact is lost or excessive, enabling high productivity while maintaining reliable tissue damage control through continuous adaptation to changing conditions.

Inventive Principle:
Principle #15Dynamics

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

Enables precise and controlled ablation by correlating mechanical force with RF power and time, reducing tissue damage and improving the accuracy of ablation volume prediction and visualization, thereby enhancing the safety and efficacy of cardiac ablation procedures.

Implementation Method 1

RF energy is applied through the catheter to the electrode in order to ablate the heart tissue at the site

Methodology Applied
Scientific EffectRadio-frequency energy heating: Dielectric Heating

Implementation Method 2

ablating the tissue at the site using the electrode

Methodology Applied
Scientific EffectAblation: Ablation

Implementation Method 3

A pressure transducer measures the contact pressure

Methodology Applied
Scientific EffectPressure sensing: Piezoresistive Effect

Data Source

PatentEP2338428B1Estimation and mapping of ablation volume
Publication Date: 2015.08.26 BIOSENSE WEBSTER (ISRAEL) LTD
  • EP2338428B1 patent drawingFigure 1
  • EP2338428B1 patent drawingFigure 2~3
  • EP2338428B1 patent drawingFigure 4

AI summary

Tissue ablation systems are provided, wherein a cardiac catheter incorporates a pressure detector for sensing a mechanical force against the distal tip when engaging an ablation site. Responsively to the pressure detector, a controller computes an ablation volume according to relationships between the contact pressure against the site, the power output of an ablator, and the energy application time. A monitor displays a map of the heart which includes a visual indication of the computed ablation volume. The monitor may dynamically display the progress of the ablation by varying the visual indication.