Transmural Ablation Power Modulation via Impedance Plateau Detection

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Solution Overview

Problem

Current transmural ablation methods are inefficient and prone to over-ablation due to reliance on impedance curves that do not consistently plateau, especially in fatty or inhomogeneous tissues, leading to incomplete tissue ablation.

Innovation Solution

A device that applies ablation energy, monitors tissue impedance, and reduces energy when impedance rises, using a power modulation algorithm to detect transmurality through impedance and temperature feedback, ensuring efficient and complete tissue ablation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional impedance-based transmurality detection is used, then ablation can be performed, but the procedure is inefficient and prone to over-ablation due to inconsistent impedance plateau formation

Engineering Contradiction:
Improveablation efficiencyVSAvoidtransmurality detection accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system continuously monitors tissue impedance during ablation and uses this feedback to detect transmurality. When a characteristic impedance plateau is detected, the system automatically terminates the ablation, providing real-time feedback control that adapts to tissue properties and eliminates the need for fixed time or power protocols.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system monitors changes in electrical impedance parameters during ablation. By detecting specific patterns in impedance parameter evolution (particularly the plateau pattern), the system can reliably determine when transmurality has been achieved, adapting to variations in tissue composition including fatty tissues.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If ablation continues until impedance plateau is detected or minimum time delay occurs, then transmurality is achieved, but over-ablation occurs resulting in unnecessary energy delivery and tissue damage

Engineering Contradiction:
Improvetransmurality completionVSAvoidtissue damage from over-ablation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system uses real-time impedance monitoring to provide feedback on ablation progress. When the characteristic plateau pattern is detected, the system immediately terminates ablation, preventing over-ablation. This feedback mechanism stops energy delivery at the precise moment transmurality is achieved, eliminating unnecessary energy exposure.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system establishes predetermined impedance plateau detection criteria before ablation begins. By having these detection thresholds and patterns pre-programmed, the system can immediately recognize and respond to transmurality conditions, terminating ablation at the optimal moment without requiring conservative time delays.

Inventive Principle:
Principle #10Preliminary action

3Object-affected harmful factors

If ablation terminates on impedance rise due to temperature increase, then over-ablation is prevented, but incomplete ablation occurs in fatty or inhomogeneous tissues where plateau does not form

Engineering Contradiction:
Improveover-ablation preventionVSAvoidtransmurality achievement
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system monitors the pattern of impedance parameter changes over time during ablation. By analyzing the characteristic plateau pattern in impedance evolution, the system can distinguish between impedance rises indicating transmurality completion and those indicating tissue drying or fat ablation, ensuring reliable detection across different tissue types.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The continuous impedance monitoring provides real-time feedback that adapts to the specific tissue being ablated. The system recognizes the characteristic plateau pattern that occurs with transmural ablation regardless of tissue type, allowing it to achieve reliable transmurality detection in fatty and inhomogeneous tissues without premature termination.

Inventive Principle:
Principle #23Feedback

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 enables precise control of ablation energy delivery, reducing the time and energy required for transmural ablation while minimizing the risk of over-ablation and tissue damage, particularly in challenging tissue types like fat.

Implementation Method 1

applying ablation energy to the tissue site

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

monitoring impedance of the tissue site

Methodology Applied
Scientific EffectElectrical impedance measurement: Electrical Resistance

Data Source

PatentEP2076195B1Transmural ablation systems
Publication Date: 2015.12.02 MEDTRONIC INC
  • EP2076195B1 patent drawingFigure 1
  • EP2076195B1 patent drawingFigure 2
  • EP2076195B1 patent drawingFigure 3~4a

AI summary

A method of applying ablation energy to achieve transmurality including applying ablation energy at a starting power to a tissue site and monitoring the impedance of the tissue site. The power applied to the tissue site can be increased in response to detection of a power plateau or application of a first power for a minimum time according to some embodiments. A power applied to the tissue site can be reduced in response to an increase in impedance according to some embodiments. Transmurality can be indicated in response to a transmurality plateau following a rise in impedance according to some embodiments.