Catheter ECG Ground Referencing for Unipolar Signal Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Legacy catheter-based systems face challenges in accurately measuring unipolar ECG signals from modern diagnostic catheters due to differences in electrical ground and timing synchronization between the analog to digital converter (ADC) module and the legacy system's Wilson Central Terminal (WCT) ground, leading to incorrect amplitudes and desynchronized signals.
Innovation Solution
The solution involves assigning a first unipolar electrode as a common electrical ground and timing reference, digitizing the signals, and using a processor to estimate and apply ground and timing offsets to synchronize and correct the signals, enabling accurate measurement of multiple unipolar ECG signals by routing them through a cross-correlator circuit and applying high-pass filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a first unipolar electrode is assigned as a common electrical ground and timing reference, then signal synchronization and ground offset correction are improved, but device complexity increases due to additional processing requirements
Solution Approach 1:
A dedicated first unipolar electrode is assigned as an intermediary reference element that mediates between the analog body-surface signal and the digital unipolar signals. This electrode serves as a common electrical ground and timing reference, enabling accurate synchronization and ground offset correction without requiring complex processing of all electrode signals.
Solution Approach 2:
The system performs preliminary actions by estimating ground offset and timing offset between analog and digital signals before actual ECG measurement. This pre-calibration process establishes reference values that are then applied during signal acquisition, simplifying subsequent processing while maintaining high measurement precision.
2Measurement precision
If ground offset and timing offset are estimated and applied, then measurement accuracy of unipolar signals is improved, but processing time increases
Solution Approach 1:
Ground offset and timing offset are estimated in advance during an initial calibration phase before actual ECG measurements are performed. These offset values are stored and applied during subsequent measurements, ensuring high accuracy without adding processing time to routine measurements.
Solution Approach 2:
The system creates a reference model of the ground and timing offsets from the first unipolar electrode and applies this copied reference information to correct all other unipolar electrode signals. This approach avoids processing each signal individually for offset correction, reducing overall processing time while maintaining accuracy.
3Adaptability or versatility
If multiple unipolar signals are digitized and processed through cross-correlator circuit, then diagnostic capability is improved, but device complexity increases
Solution Approach 1:
The processing system is segmented into functional modules: a cross-correlator circuit for timing synchronization, a ground offset correction module, and a signal processing module. This segmentation allows each component to perform its specific function efficiently while maintaining overall system versatility for multiple diagnostic applications.
Solution Approach 2:
The processing system is designed with multi-functionality to handle various ECG measurement configurations and diagnostic requirements. The same infrastructure (cross-correlator, offset correction, digitization) supports multiple unipolar electrode arrangements and different diagnostic protocols, maximizing adaptability without proportionally increasing complexity.
Data Source
AI summary
A method includes receiving analog body-surface signal from body-surface electrode, and multiple analog unipolar signals from multiple unipolar electrodes of an invasive probe. A first unipolar electrode is assigned to serve as a common electrical ground and a common timing reference for the analog unipolar signals and the analog body-surface signal. The analog unipolar signals are digitized to produce digital unipolar signals sampled relative to a digital ground. Defined are an analog bipolar signal between the first unipolar electrode and a second unipolar electrode of the probe, and digital bipolar signal formed from the first unipolar electrode and the second unipolar electrode. Ground and timing offsets between the analog bipolar signal and the digital bipolar signal are estimated, while the first unipolar electrode is connected to the digital ground. The ground offset and the timing offset are applied in measuring a third unipolar signal, sensed by a third unipolar electrode.