Catheter Impedance Measurement for Cardiac Tissue Temperature Control
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Solution Overview
Problem
Existing methods for cardiac tissue ablation using radiofrequency energy face challenges in controlling local heating, leading to either ineffective lesions or excessive tissue damage due to overheating, which complicates the procedure and prolongs treatment time.
Innovation Solution
A method and apparatus that measure impedance between irrigated electrodes on a catheter to estimate tissue temperature, allowing for real-time adjustment of the ablation electrode's power level to maintain optimal temperature, thereby preventing overheating and ensuring effective lesion creation without excessive tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radiofrequency energy is applied at high power to create large lesions, then ablation effectiveness is improved, but tissue overheating and damage occur
Solution Approach 1:
The patent implements a feedback control system that continuously monitors tissue temperature during ablation and dynamically adjusts radiofrequency power delivery. Temperature sensors provide real-time feedback to the control system, which modulates the power level to maintain temperature within a therapeutic window, thereby achieving effective ablation while preventing overheating and tissue damage.
Solution Approach 2:
The system dynamically changes the power parameter of radiofrequency energy delivery based on real-time temperature measurements. By adjusting the power level in response to temperature feedback, the system optimizes the balance between creating sufficient thermal damage for effective ablation and avoiding excessive heating that causes tissue charring and steam pops.
2Productivity
If radiofrequency power is increased to reduce procedure time, then productivity is improved, but tissue damage increases
Solution Approach 1:
The feedback control system enables safe operation at higher power levels by continuously monitoring temperature and automatically reducing power when temperature thresholds are approached. This allows the system to deliver higher energy doses more quickly than traditional methods while maintaining temperature control, thereby reducing procedure time without increasing tissue damage.
3Object-affected harmful factors
If slower heating is used to control ablation, then tissue damage is reduced, but procedure time increases
Solution Approach 1:
The system dynamically adjusts the heating rate based on real-time temperature feedback. Rather than using a fixed slow heating rate, the system can operate at high power when temperatures are low and automatically reduces power as temperatures approach the target range, enabling both rapid ablation and precise temperature control throughout the procedure.
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
This approach enables precise control over tissue ablation, reducing the risk of overheating and shortening procedure time by iteratively measuring impedance and adjusting power levels, ensuring effective lesion creation while minimizing tissue damage.
Implementation Method 1
temperature is measured according to the changes in impedance between a pair of irrigated electrodes on a catheter
Implementation Method 2
Ablation of body tissue using electrical energy is known in the art. The ablation is typically performed by applying alternating currents, for example radiofrequency energy, to the electrodes, at a sufficient power to destroy target tissue
Data Source
AI summary
Ablation of cardiac tissue is carried out by inserting a probe having an ablation electrode and a plurality of microelectrodes into a body of a living subject to establish contact between two of the microelectrodes and target tissue, and energizing the ablation electrode. While the ablation electrode is energized impedances are measured between the microelectrodes, and the power level of the ablation electrode adjusted according to the impedances.