Ablation Catheter Real-Time Lesion Estimation
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Solution Overview
Problem
Existing ablation catheters face challenges in controlling the delivery of RF energy to prevent excessive tissue damage, such as steam pop, charring, and undesirable coagulum formation, while aiming to form adequately deep lesions, due to high temperature gradients and edge effects at the electrode.
Innovation Solution
An ablation catheter system with programmable power sources, voltage and current measurement devices, phase measurement, and a lesion analysis processor to estimate lesion formation based on phase change, power level, and delivery time, providing feedback and controlling energy delivery to prevent excessive tissue temperature and ensure desired lesion depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature is applied to form deep lesions quickly, then lesion formation speed is improved, but tissue damage such as charring and coagulum formation increases
Solution Approach 1:
The system continuously monitors tissue temperature during ablation and provides real-time feedback to adjust RF energy delivery. Temperature sensors detect temperature changes and feed this information back to the control system, which modulates power delivery to maintain optimal ablation temperature while preventing excessive heating that causes charring and coagulum formation.
Solution Approach 2:
The ablation system dynamically adjusts RF power delivery based on real-time tissue temperature measurements and lesion depth estimation. The system transitions from static fixed-power ablation to dynamic adaptive ablation, where power levels are continuously modified during the procedure to optimize lesion formation while preventing tissue damage.
2Length of stationary object
If high power RF energy is delivered to create deep lesions, then lesion depth is improved, but temperature gradients cause edge effects and charring
Solution Approach 1:
The system applies different power levels to different regions of the electrode based on local tissue conditions and real-time temperature measurements. By segmenting the electrode into multiple independent heating zones and controlling each zone's power delivery separately, the system creates uniform temperature distribution that prevents edge effects and charring while achieving adequate lesion depth.
Solution Approach 2:
The system continuously monitors and adjusts multiple ablation parameters including RF power level, duty cycle, and pulse duration based on real-time temperature feedback and lesion depth estimation. This dynamic parameter adjustment ensures uniform energy distribution throughout the tissue volume, preventing localized overheating at electrode edges while maintaining sufficient power for deep lesion formation.
3Manufacturing precision
If real-time lesion monitoring is implemented, then control precision is improved, but device complexity increases
Solution Approach 1:
The ablation catheter integrates multiple functions into a single device: RF energy delivery, temperature sensing, lesion depth estimation, and real-time monitoring are all combined in one system. The electrode serves both as the ablation element and as a sensor platform, eliminating the need for separate monitoring devices and reducing overall system complexity despite the advanced capabilities provided.
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 effectively controls RF energy delivery to minimize tissue damage, providing real-time feedback on lesion formation and depth, reducing the risk of complications like charring and coagulum formation, while ensuring deep and precise lesion creation.
Implementation Method 1
catheters may be used to accomplish radiofrequency (RF) ablation by transmission of RF energy to a desired target area through an electrode assembly to ablate tissue at the target site. RF energy may generate significant heat
Implementation Method 2
RF energy may generate significant heat, which if not controlled, can result in excessive tissue damage
Implementation Method 3
a phase measurement device to determine an amount of phase change between the measured voltage signal and the measured current signal
Implementation Method 4
a lesion analysis processor for estimating lesion formation as a function of at least: the measured phase change between the voltage signal and the current signal; information indicating the programmable power level at which the power source delivers ablative power to tissue
Data Source
AI summary
Disclosed herein are ablation systems and methods for providing feedback on lesion formation in real-time. The methods and systems assess absorptivity of tissue based on a degree of electric coupling or contact between an ablation electrode and the tissue. The absorptivity can then be used, along with other information, including, power levels and activation times, to provide real-time feedback on the lesions being created. Feedback may be provided, for example, in the form of estimated lesion volumes and other lesion characteristics. The methods and systems can provide estimated treatment times to achieve a desired lesion characteristic for a given degree of contact, as well as depth of a lesion being created. The degree of contact may be measured using different techniques, including the phase angle techniques and a coupling index.