Electrogram Screening for Injury Current in Cardiac EP Mapping
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Solution Overview
Problem
Existing electrophysiological mapping techniques are hindered by injury current, which causes baseline wander and degrades signal quality, leading to errors in annotation of late activation times during cardiac EP mapping.
Innovation Solution
A method and system for detecting and mitigating the effects of injury current by using a multi-electrode catheter with a central reference electrode, comparing baseline levels with a Wilson Central Terminal configuration, and dropping signals exceeding a threshold to maintain signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If baseline correction is applied to remove noise, then measurement precision is improved, but injury current causes baseline wander that cannot be fully corrected
Solution Approach 1:
The patent extracts and removes signals identified as containing injury current by comparing electrogram characteristics against predefined criteria. Distorted signals are separated from valid signals through detection algorithms that identify baseline wander patterns, allowing clean signals to be processed while excluding contaminated ones.
Solution Approach 2:
The patent changes the approach from attempting to correct baseline wander through traditional baseline correction to instead detecting and excluding signals that exhibit injury current characteristics. By monitoring signal parameters such as baseline stability and electrogram morphology, the system identifies and removes affected signals rather than trying to correct them.
2Productivity
If all acquired electrograms are used for mapping, then productivity is improved, but annotation accuracy deteriorates due to injury current distortion
Solution Approach 1:
The patent implements a feedback mechanism where each acquired electrogram is automatically evaluated against injury current detection criteria before being included in the mapping. The system provides real-time quality assessment, accepting or rejecting signals based on their characteristics, thereby maintaining high productivity while ensuring annotation accuracy through automated quality control.
Solution Approach 2:
The patent performs preliminary detection and filtering of injury current-affected signals before they are used for activation time annotation. By pre-screening electrograms and excluding distorted signals in advance, the system ensures that only high-quality signals proceed to mapping, maintaining both productivity and accuracy without requiring post-processing corrections.
3Stability of the object's composition
If high-pass filtering is applied to remove injury current, then baseline stability is improved, but signal artifacts remain that cause mapping errors
Solution Approach 1:
Instead of relying on high-pass filtering that leaves residual artifacts, the patent extracts and removes the problematic signals entirely by detecting injury current characteristics. This approach eliminates both the baseline instability and the remaining artifacts that would otherwise persist after filtering, providing a cleaner solution.
Solution Approach 2:
The patent converts the harmful effect of injury current into a useful detection signal. By monitoring for the specific patterns caused by injury current (baseline wander, signal distortion), the system identifies and excludes affected signals, transforming what was previously a source of error into a reliable indicator for quality control.
Data Source
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AI summary
A system includes an interface and a processor. The interface is configured to receive an electrogram acquired in a heart of a patient. The processor is configured to (i) estimate a level of injury current present in the electrogram, and (ii) based on the estimated level of injury current, decide whether to use the electrogram in a subsequent analysis.