Catheter ECG Signal Synchronization Using a Shared Unipolar Reference
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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 routing and processing requirements
Solution Approach 1:
The patent combines the electrical ground and timing reference functions into a single first unipolar electrode, eliminating the need for separate ground and timing reference electrodes. This merging approach resolves the technical contradiction by achieving both ground offset correction and timing synchronization through one integrated reference point, thereby improving measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The first unipolar electrode serves multiple functions simultaneously: it acts as an electrical ground reference, a timing reference, and a signal measurement electrode. This multi-functionality allows the system to achieve accurate signal synchronization and ground offset correction while minimizing the number of dedicated reference components, thus resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If ground offset and timing offset are estimated and applied to correct signal discrepancies, then measurement accuracy is improved, but processing time and computational complexity increase
Solution Approach 1:
The patent performs ground offset and timing offset estimation during an initial calibration phase before actual ECG signal measurement. By pre-calculating and storing these offset values, the system eliminates the need for real-time offset calculation during patient monitoring, thereby improving measurement accuracy while minimizing processing time loss during critical measurement periods.
Solution Approach 2:
The system continuously monitors signal quality and automatically adjusts for ground and timing offsets using pre-established reference values. This feedback mechanism ensures high measurement accuracy without requiring complex real-time computational processing, as the offset corrections are applied based on previously determined parameters rather than continuous calculation.
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.