Catheter Impedance Detection for Phrenic Nerve Stimulation
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Solution Overview
Problem
During cardiac ablation procedures, existing methods fail to effectively prevent damage to the phrenic nerve, which can be stimulated by pacing currents, leading to unintended tissue ablation and potential nerve injury.
Innovation Solution
A system utilizing a catheter with electrodes to navigate and identify the proximity of the phrenic nerve by measuring impedance changes caused by pacing currents, generating a warning to prevent ablation when stimulation is detected, and using the same electrodes for navigation and stimulation without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pacing currents are delivered to navigate and stimulate tissue during cardiac ablation, then catheter navigation and tissue stimulation are achieved, but phrenic nerve stimulation occurs leading to unintended tissue ablation and potential nerve injury
Solution Approach 1:
The system performs preliminary detection of phrenic nerve proximity by measuring impedance changes during pacing currents before delivering ablation energy. This allows the system to identify at-risk locations and prevent ablation near the phrenic nerve, thereby preventing nerve injury before it can occur.
Solution Approach 2:
The system continuously monitors impedance changes during pacing and uses this feedback to determine phrenic nerve stimulation. When stimulation is detected, the system provides feedback to prevent further ablation at that location, creating a closed-loop safety mechanism that adapts to real-time physiological responses.
2Measurement precision
If additional sensors are added to detect phrenic nerve stimulation, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent repurposes existing electrodes already present on the catheter for navigation and stimulation to also serve as impedance sensing elements for phrenic nerve detection. This multi-functional use of existing components eliminates the need for additional dedicated sensors, maintaining detection capability while avoiding increased device complexity.
Solution Approach 2:
The system uses its own existing electrodes and pacing currents to generate the impedance signals needed for nerve detection. Rather than requiring separate sensing components, the system leverages its operational components to provide self-diagnostic capability for phrenic nerve proximity detection.
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
Effectively prevents phrenic nerve damage by accurately identifying nerve stimulation through impedance patterns, allowing for safe catheter placement and avoiding tissue ablation near the nerve, thus enhancing procedural safety.
Implementation Method 1
measuring impedance changes caused by pacing currents
Data Source
AI summary
Described embodiments include an apparatus, including a display and a processor. The processor is configured to navigate a catheter to a particular location within a body of a subject, using each one of a plurality of electrodes coupled to the body of the subject. The processor is further configured to identify, subsequently, from a signal that represents an impedance between a given pair of the electrodes, that a phrenic nerve of the subject was stimulated by a pacing current passed from the catheter into tissue of the subject at the particular location, and to generate an output on the display, in response to the identifying. Other embodiments are also described.