Accelerometer-Based Contact Sensing for Catheter Electrodes
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Solution Overview
Problem
Current electrophysiology catheters face challenges in maintaining consistent mechanical contact between electrodes and tissue, particularly in dynamic environments like the beating heart, leading to false positive readings and sensitivity to thermal changes, which complicates procedures like RF ablation.
Innovation Solution
The use of accelerometers coupled to electrodes or carriers to measure acceleration and determine forces acting on the electrodes, allowing for accurate detection of tissue contact by analyzing acceleration vectors and comparing forces to eliminate false positives and thermal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force sensing methods are used to detect electrode contact with tissue, then contact detection capability is improved, but the system becomes sensitive to thermal changes during ablation procedures, leading to incorrect readings
Solution Approach 1:
The patent replaces force sensing methods with accelerometer-based detection. Instead of using mechanical force sensors that are sensitive to thermal changes during RF ablation, the system uses accelerometers to detect tissue contact through mechanical acceleration events. This substitution eliminates thermal sensitivity while maintaining contact detection capability, as accelerometers respond to dynamic motion rather than static force or thermal conditions.
2Measurement precision
If remotely placed sensors are used to detect electrode contact, then contact monitoring is improved, but false positive readings occur when the catheter wall contacts tissue instead of the electrode
Solution Approach 1:
The patent segments the detection function by placing accelerometers directly on the electrode rather than remotely on the catheter shaft. This segmentation ensures that only acceleration events occurring at the electrode itself are detected, eliminating false positives from catheter wall contact. The sensor is divided into distinct functional components: the electrode and the accelerometer, with the accelerometer mounted directly to the electrode to ensure spatial correspondence between the sensing element and the tissue contact point.
Solution Approach 2:
The patent introduces a carrier as an intermediary structure that mechanically couples the accelerometer to the electrode. This carrier serves as a mediator that transmits acceleration events from the electrode to the accelerometer while providing a stable mounting platform. The carrier ensures that the accelerometer accurately follows the electrode's motion without being influenced by unrelated catheter movements, thereby eliminating false positive readings.
3Ease of operation
If the electrode is placed 150 cm away from the operator's hand for endocardial applications, then access to the heart is improved, but maintaining consistent mechanical contact between electrode and tissue becomes difficult
Solution Approach 1:
The patent implements real-time feedback by using accelerometers to detect tissue contact events and providing immediate information about contact status. The system monitors acceleration patterns that indicate tissue interaction and provides feedback to the operator, enabling dynamic adjustment of catheter positioning. This feedback loop compensates for the difficulty of maintaining consistent contact over the 150 cm distance, as operators can respond to real-time contact detection rather than relying solely on manual positioning precision.
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 significantly reduces false positive readings of electrode contact with tissue, ensuring consistent and accurate contact during procedures, enhancing the effectiveness of ablation and diagnostic processes by providing reliable feedback on electrode-tissue interaction.
Implementation Method 1
One or more accelerometers are coupled to an electrode. Signals received from the one or more accelerometers are used to determine either or both of the magnitude and the direction of the acceleration of the electrode.
Implementation Method 2
the force acting on the electrode may be determined from the acceleration of the electrode. For example, the electrode may have a known mass, so the force may be derived by a processor configured to multiply the mass by the acceleration, since Force (F)=Mass (m)×Acceleration (a), i.e. F=ma.
Data Source
AI summary
A catheter system including an accelerometer-based sensing assembly is provided. In particular the present teachings relate to an accelerometer based assembly used to determine contact between a catheter and surrounding proximate tissue, such as cardiac tissue. An embodiment of such a system may, for example, be used for visualization, mapping, ablation, or other methods of diagnosis and treatment of tissue and/or surrounding areas.