Phrenic Nerve Warning System Using Magnetic Diaphragm Tracking
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Solution Overview
Problem
During cardiac ablation procedures, there is a risk of damaging the phrenic nerve due to the proximity of the ablation electrode to the nerve, which can lead to unintended tissue damage, and existing methods rely on manual observation of diaphragm motion, lacking automation and precision.
Innovation Solution
A system that includes a catheter with electrodes, a body surface patch for position sensing, and a processor to compute an index of diaphragm movement, providing alerts and controlling the ablation power generator to prevent nerve damage, using magnetic field generators and sensors to track movement and proximity to the phrenic nerve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual observation of diaphragm motion is used to detect phrenic nerve proximity, then the system complexity is low, but the measurement precision and reliability are insufficient
Solution Approach 1:
The patent replaces manual visual observation of diaphragm motion with an automated magnetic field sensing system. Body surface patches equipped with magnetic sensors detect diaphragm movement through magnetic field changes, converting a mechanical observation task into an automated electromagnetic detection system. This substitution significantly improves measurement precision while the modular patch design keeps the overall system complexity manageable.
Solution Approach 2:
The patent introduces magnetic field generators and magnetic sensors as intermediary elements between the diaphragm and the detection system. The magnetic field acts as a mediator that translates diaphragm movement into detectable signals, enabling precise automated measurement without direct mechanical contact or complex imaging systems.
2Extent of automation
If automated detection system with body surface patches is implemented, then the measurement precision and automation extent improve, but the device complexity increases
Solution Approach 1:
The body surface patches are designed as self-contained units that autonomously generate magnetic fields, sense diaphragm movement, and transmit data to the processing system. Each patch operates independently, performing its own field generation and sensing functions without requiring external control, thereby achieving high automation while maintaining relatively simple individual component design.
Solution Approach 2:
The detection system is divided into multiple independent body surface patches, each functioning as a separate modular unit. This segmentation allows the automated detection capability to be distributed across multiple simple components rather than concentrated in one complex system, making the overall implementation more manageable and scalable.
3Reliability
If real-time monitoring and alert system are implemented, then the reliability and safety improve, but the device complexity and energy consumption increase
Solution Approach 1:
The system implements periodic monitoring of diaphragm movement through intermittent activation of magnetic field generators and sensing cycles, rather than continuous operation. The processor evaluates diaphragm movement indices at regular intervals during the ablation procedure, providing real-time safety monitoring while allowing energy conservation during periods when no significant movement is expected.
Solution Approach 2:
The system employs feedback mechanisms where the processor continuously evaluates the diaphragm movement index and provides alerts or adjusts ablation power based on detected movement. This feedback loop ensures high reliability by immediately responding to nerve proximity indicators, while the intelligent activation only when movement thresholds are approached helps manage energy consumption.
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
Automatically detects and alerts the physician of the proximity of the catheter electrode to the phrenic nerve, preventing potential nerve damage by adjusting the ablation power and providing tactile, audio, or visual alerts, enhancing the precision and safety of the procedure.
Implementation Method 1
Magnetic location sensing is one of the methods known in the art. In magnetic location sensing, magnetic field generators are typically placed at known locations external to the patient. A magnetic field sensor within the distal end of the probe generates electrical signals in response to these magnetic fields
Implementation Method 2
RF (radio frequency) current is applied through the tip electrode(s) of the ablating catheter, and current flows through the media that surrounds it, i.e., blood and tissue, between the tip electrode(s) and an indifferent electrode. The distribution of current depends on the amount of electrode surface in contact with the tissue as compared to blood, which has a higher conductivity than the tissue. Heating of the tissue occurs due to its electrical resistance.
Implementation Method 3
at least one body surface patch configured to be applied to a body surface of the living subject, and provide at least one position signal
Data Source
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AI summary
In one embodiment, an ablation system includes a catheter including at least one electrode, and configured to be inserted into a chamber of a heart of a living subject, an ablation power generator configured to apply an electrical signal to the at least one electrode to ablate tissue of the chamber, at least one body surface patch configured to be applied to a body surface of the living subject, and provide at least one position signal, and a processor configured to compute an index of a measurement of diaphragm movement responsively to the at least one position signal, and perform an action responsively to the computed index.