Implantable Lead Breach Detection via Cross-Lead Impedance
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Solution Overview
Problem
Implantable cardiac rhythm management devices face challenges in detecting insulation breaches in leads, which can lead to improper therapy delivery and device failure due to the insensitivity of existing impedance measurement techniques for early detection of small impedance changes caused by abrasion or other lead failures.
Innovation Solution
A method involving the measurement of impedance along single-lead and cross-lead vectors between electrodes to derive a sensitive impedance value that detects insulation breaches by identifying significant deviations over time, using a combination of measurements from right ventricular and right atrial leads to detect shunt impedance changes indicative of a breach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional bipolar impedance measurement is used between tip and ring electrodes, then the measurement is simple to perform, but the sensitivity for detecting early insulation breaches is insufficient
Solution Approach 1:
The patent segments the impedance measurement system by introducing multiple measurement vectors (single-lead vectors and cross-lead vectors) instead of using a single bipolar measurement. This segmentation allows the system to detect insulation breaches at different locations along the lead by measuring impedance between different electrode combinations, thereby improving detection sensitivity without requiring a complete redesign of the measurement system
Solution Approach 2:
The patent uses cross-lead impedance measurements as an intermediary method to detect insulation breaches. By measuring impedance between electrodes on different leads (cross-lead vectors) in addition to traditional single-lead measurements, the system creates additional detection pathways that are more sensitive to insulation breaches, acting as an intermediary detection mechanism between the lead and the detection system
2Reliability
If multiple impedance vectors are measured to improve detection sensitivity, then early detection capability is enhanced, but the measurement and calculation complexity increases
Solution Approach 1:
The patent adds another dimension to impedance measurement by introducing cross-lead vectors that measure impedance between different leads, in addition to the traditional single-lead vectors. This dimensional expansion creates a more comprehensive measurement space that improves detection reliability by providing multiple perspectives on lead integrity, while the systematic approach to vector selection manages the complexity of measurements required
3Loss of time
If traditional impedance measurement is used, then the system operation is simple, but lead failures may go undetected until complete failure occurs
Solution Approach 1:
The patent implements preliminary detection action by continuously monitoring multiple impedance vectors to detect insulation breaches before they progress to complete lead failure. The system performs preliminary assessments using cross-lead vectors that are more sensitive to early-stage insulation degradation, providing advance warning that allows clinicians to replace leads proactively before catastrophic failure occurs, thereby reducing the time loss associated with unexpected lead failures
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 allows for early detection of lead breaches, enabling timely replacement and preventing complete failure, thereby ensuring reliable signal sensing and therapy delivery.
Implementation Method 1
values representative of impedance are measured along various single-lead vectors (i.e. intra-lead vectors) between pairs of electrodes of each individual lead
Data Source
AI summary
Techniques are provided for use with an implantable medical device for detecting breaches in lead insulation or other lead failures. In one example, bipolar impedance is measured along single-lead vectors (i.e. intra-lead vectors) of a right atrial (RA) lead and a right ventricular (RV) leads. Impedance is also measured along various cross-lead vectors (i.e. inter-lead vectors) between electrodes of the two leads. A derived impedance value is then determined from a combination of the measured impedance values, wherein the derived impedance is sensitive to a shunt impedance arising from a breach within the RV lead. A lead breach is then detected relatively early based on the derived impedance by detecting a significant deviation in derived impedance over time. Unipolar impedance measurements are used to confirm the breach.