CRT Pacing Vector Selection Using RV-LV Delay Screening
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Solution Overview
Problem
The challenge in implantable cardiac rhythm management devices, such as CRT devices, is the difficulty in selecting optimal pacing vectors due to patient variability in venous anatomy and lead migration, which can result in diaphragmatic stimulation and increased LV capture thresholds, requiring complex and time-consuming threshold testing.
Innovation Solution
A method that measures RV-LV delay times using different LV electrodes as sensing cathodes to identify the LV electrode with the longest delay, then performs capture and diaphragmatic stimulation threshold tests to select suitable pacing vectors, reducing the number of vectors to be tested and simplifying the workflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all programmable pacing vectors are tested to identify suitable vectors, then the reliability of vector selection is improved, but the time and complexity of the testing process increases
Solution Approach 1:
The patent segments the comprehensive vector selection process into two distinct phases: (1) an initial rapid screening phase using RV-LV delay measurements to identify candidate vectors, and (2) a detailed threshold testing phase only for those candidate vectors. This segmentation reduces the number of vectors requiring comprehensive threshold testing while maintaining selection reliability.
Solution Approach 2:
The patent performs preliminary RV-LV delay measurements before conducting threshold tests. This preliminary action identifies which LV electrodes have the latest activation timing, allowing the system to pre-select candidate vectors for threshold testing rather than testing all possible vectors, thereby reducing overall testing time.
2Measurement precision
If comprehensive threshold testing is performed for all vectors, then the accuracy of identifying suitable pacing vectors is improved, but the device complexity and operational complexity increase
Solution Approach 1:
The patent divides the vector selection process into sequential stages: first measuring RV-LV delays for all vectors, then using those results to select only candidate vectors for threshold testing. This segmentation maintains measurement accuracy for the final selection while reducing procedural complexity by avoiding unnecessary tests.
Solution Approach 2:
The patent applies partial action by performing threshold testing on only a subset of vectors (those identified as candidates through RV-LV delay measurement) rather than all programmable vectors. This partial testing approach maintains sufficient accuracy for clinical decision-making while reducing complexity.
3Adaptability or versatility
If lead migration occurs causing threshold changes, then the adaptability of the pacing system is improved through electronic repositioning, but the time required to identify new suitable vectors increases
Solution Approach 1:
The patent establishes a preliminary RV-LV delay measurement step that can be quickly performed when lead migration is detected. This preliminary measurement rapidly identifies new candidate vectors following migration, enabling fast electronic repositioning without requiring comprehensive re-testing of all vectors.
Solution Approach 2:
The patent allows for discarding previously optimized vector settings when lead migration is detected (indicated by threshold changes), and recovering new suitable vectors through the expedited RV-LV delay measurement and candidate selection process, enabling efficient adaptation to new lead positions.
Data Source
AI summary
Techniques are provided for use with an implantable cardiac stimulation device equipped with a multi-pole left ventricular (LV) lead and a right ventricular (RV) lead for identifying suitable pacing vectors. In one example, RV-LV delay times are measured while using different electrodes of the LV lead as cathodes for sensing. The LV electrode having the longest RV-LV delay time is identified and LV capture thresholds and diaphragmatic stimulation thresholds are measured for pacing vectors that employ that LV electrode as a cathode. Assuming at least one vector employing the selected LV electrode is found to have acceptable thresholds, the vector is selected for use in delivering pacing therapy with the selected LV electrode. If none of the pacing vectors employing the selected LV electrode has acceptable thresholds, another LV electrode is selected and the procedure is repeated. Examples with a multi-pole RV lead are also described.