Microelectrode Ablation Catheter for Accurate MAP Signal Sensing
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Solution Overview
Problem
Existing catheters struggle to obtain accurate local electrical signals, such as monophasic action potentials (MAPs), due to interference from far-field electrical activity, which can distort local electrical activity measurements.
Innovation Solution
A catheter with microelectrodes and thermocouples that apply a controlled, reversible localized trauma to tissue, allowing for the measurement of MAP signals while minimizing noise and ensuring consistent force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multiple-electrode catheter is used to measure electrical activity at multiple points, then simultaneous measurement capability is improved, but far-field electrical activity interference increases, distorting local electrical activity measurements
Solution Approach 1:
The catheter employs multiple discrete electrode elements (including microelectrodes and macroelectrodes) positioned at different locations along the catheter shaft, allowing simultaneous measurement of electrical activity at multiple points while enabling selective use of specific electrodes to minimize far-field interference
Solution Approach 2:
The catheter incorporates microelectrodes with very small surface areas (e.g., 0.01-0.05 mm²) that are specifically designed to detect local electrical activity with high precision, while macroelectrodes with larger surface areas are used for far-field reference signals, allowing optimization of each electrode type for its specific measurement function
2Measurement precision
If microelectrodes with small surface area are used to reduce far-field interference, then local signal detection precision is improved, but signal amplitude decreases, requiring higher sensitivity amplification
Solution Approach 1:
The catheter combines microelectrodes for local signal detection with macroelectrodes for far-field reference signals, and merges these signals through differential amplification to produce monophasic action potential (MAP) recordings that enhance local signal amplitude while rejecting far-field interference
Solution Approach 2:
The system uses far-field reference electrodes to continuously monitor ambient electrical activity and feeds this information back to the signal processing system, which then subtracts the far-field component from local electrode signals to recover the true local electrical activity with preserved amplitude
3Reliability
If contact force is increased to improve tissue contact and signal quality, then measurement reliability is improved, but risk of tissue damage increases
Solution Approach 1:
The catheter incorporates a force sensor that dynamically monitors contact force between the catheter tip and tissue, allowing real-time adjustment of contact pressure to maintain optimal signal quality while preventing excessive force that could cause tissue damage
Solution Approach 2:
The force sensor provides continuous feedback on contact force to the control system, which adjusts catheter positioning or irrigation flow to maintain reliable tissue contact without exceeding safe force thresholds, thereby ensuring both signal quality and tissue safety
4Reliability
If irrigation flow rate is increased to improve heat dissipation during ablation, then temperature control reliability is improved, but fluid delivery complexity increases
Solution Approach 1:
The irrigation system is integrated with the electrical signal recording and ablation functions, allowing the same fluid delivery mechanism to serve multiple purposes: cooling the tissue during ablation, maintaining catheter-tissue contact through hydrodynamic force, and potentially serving as a conductive medium for electrical signals
Solution Approach 2:
The irrigation flow automatically adjusts based on thermal feedback from temperature sensors, with the system self-regulating the flow rate to maintain optimal temperature without requiring manual intervention, thereby simplifying operation despite the integrated complexity
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
Enables high-fidelity reproduction of transmembrane action potential repolarization time courses, facilitating better tissue response analysis and therapeutic decision-making.
Implementation Method 1
microelectrodes can be utilized to cause a localized therapeutic trauma on the tissue to study MAP on the local tissue
Implementation Method 2
A catheter with microelectrodes and thermocouples that apply a controlled, reversible localized trauma to tissue
Data Source
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AI summary
A catheter having an ablation electrode with at least one microelectrode configured to sense monophasic action potential signals and a force sensor configured to sense contact force of the microelectrode against tissue surface, may be used to acquire pre-ablation MAP signals with monophasic characteristics and post-ablation MAP signals to determine presence or absence of monophasic characteristics in the latter in assessing quality or success of ablation procedure and lesion formation.