Wearable Defibrillator ECG Isolation Circuit
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Solution Overview
Problem
Wearable cardioverter defibrillators (WCDs) often experience erroneous readings and false alarms due to electrical noise interference from other system components, which can compromise patient safety and the accuracy of heart arrhythmia detection.
Innovation Solution
The implementation of separate grounds and an isolating circuit to electrically isolate patient parameter electrodes, such as ECG electrodes, from other WCD system circuits, improving the quality of physiological input sensing and reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If patient parameter electrodes are electrically connected to other WCD system circuits using common grounds, then device complexity is reduced, but measurement precision deteriorates due to electrical noise interference
Solution Approach 1:
The patent divides the WCD system into two separate ground systems: an isolated patient parameter ground and a non-isolated system ground. This segmentation prevents electrical noise from the high-power defibrillation circuits from contaminating the sensitive ECG measurement circuits, thereby improving measurement precision without requiring complete system isolation.
Solution Approach 2:
The patent introduces an isolating circuit as an intermediary component between the patient parameter electrodes and the rest of the WCD system. This isolating circuit acts as a mediator that allows electrical connection while blocking noise transmission, resolving the contradiction between maintaining simple connectivity and achieving noise-free measurements.
2Measurement precision
If separate grounds and isolating circuits are implemented to electrically isolate patient parameter electrodes, then measurement precision improves, but device complexity increases
Solution Approach 1:
The ground system is segmented into isolated and non-isolated portions, allowing the ECG circuitry to operate on a clean, isolated ground while the defibrillation circuitry uses the non-isolated ground. This segmentation achieves noise reduction with minimal added complexity by only isolating the measurement portion of the system.
Solution Approach 2:
Electrical isolation is applied locally only to the patient parameter sensing circuits where noise sensitivity is critical, rather than isolating the entire WCD system. This localized approach improves measurement precision while minimizing the overall device complexity increase.
3Reliability
If electrical isolation is implemented for patient parameter electrodes, then reliability improves by reducing false alarms, but manufacturing precision requirements increase
Solution Approach 1:
The isolating circuit serves as a standardized intermediary component that can be pre-tested and pre-assembled as a module. This modular approach reduces manufacturing precision requirements during final system assembly, as the isolating circuit handles the complex isolation requirements internally with standardized connection points.
Data Source
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AI summary
A wearable cardioverter defibrillator (WCD) system (101) is described that includes patient parameter electrodes (114, 118), such as ECG electrodes, that are at least substantially electrically isolated from other circuits of the WCD system. The WCD system includes a power source, an energy storage module and a processor, each connected to a first circuit ground. A patient parameter sense port, such as an ECG port, is coupled to the patient. A measurement circuit is configured to render a physiological input from the sensed patient parameter received at the patient parameter sense port and includes an isolating circuit that electrically isolates the patient parameter sense port from the first circuit ground.