Catheter Impedance Ratio Trigger for Contact Detection
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Solution Overview
Problem
Current catheter systems face challenges in accurately determining contact with anatomical structures, as existing methods rely on complex mechanical elements or conductivity measurements that are prone to errors due to blood conductivity variations.
Innovation Solution
A processor circuit generates a trigger signal based on a ratio between impedance measurements from different electrode sets to control the collection of electrode calibration data, ensuring accurate identification of catheter contact with anatomical structures without being influenced by blood conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If impedance measurements are used to determine catheter contact with anatomical structures, then contact detection capability is provided, but measurement accuracy deteriorates due to blood conductivity variations
Solution Approach 1:
The patent introduces a ratio calculation as an intermediary processing step between raw impedance measurements and contact determination. By computing the ratio of impedance measurements from different electrode configurations, the system creates a normalized metric that serves as a mediator, eliminating the direct influence of blood conductivity variations while preserving contact detection capability
Solution Approach 2:
The patent transforms the measurement parameter from absolute impedance values to a ratio of impedance values. This parameter transformation changes the measurement from being sensitive to blood conductivity (absolute impedance) to being insensitive to it (ratio), thereby resolving the accuracy problem while maintaining contact detection functionality
2Ease of manufacture
If manual calibration processes are used for electrode calibration, then calibration can be performed, but error susceptibility increases and productivity decreases
Solution Approach 1:
The system performs automated calibration using the ratio-based methodology without requiring manual intervention. The processor automatically calculates ratios, determines calibration states, and adjusts electrode measurements, enabling the system to self-calibrate while eliminating human error and improving both reliability and productivity
Solution Approach 2:
The patent replaces manual calibration operations with an automated computational system. Instead of physical manual adjustment and measurement, the system uses electronic processing of ratio measurements to perform calibration, substituting mechanical/manual processes with automated electronic control
3Difficulty of detecting and measuring
If complex mechanical elements are used in catheters for contact sensing, then contact detection capability is provided, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical sensing elements with an electrical measurement system based on impedance ratio calculations. Instead of using mechanical springs, force sensors, or complex mechanical linkages, the system uses electrical impedance measurements processed through ratio calculation to detect contact, thereby reducing mechanical complexity while maintaining sensing capability
Solution Approach 2:
The impedance measurement system serves multiple functions: it detects contact, provides calibration data, and enables automated control. This multi-functional approach eliminates the need for separate dedicated mechanical sensing components, reducing overall device complexity while maintaining comprehensive contact detection capability
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 provides a reliable and automated method for obtaining electrode calibration data, enhancing the accuracy of contact detection and reducing errors associated with manual calibration processes.
Implementation Method 1
an input interface configured to obtain: a first measurement, from a first set of one or more electrodes of the catheter, responsive to a change in contact and/or distance between the first set of one or more electrodes and the anatomical structure; and a second measurement, from a second, different set of one or more electrodes of the catheter, responsive to a change in contact and/or distance between the second set of one or more electrodes and the anatomical structure
Data Source
AI summary
A mechanism for providing a trigger signal that is usable to control the collection of electrode calibration data from a catheter. The trigger signal is responsive to a predictive indicator that indicates a likelihood that the catheter is in contact with the anatomical structure, and in particular examples, that the catheter is completely immersed in blood. The predictive indicator is generated using a ratio between two measurements that change responsive to touching the anatomical structure.