Implantable Defibrillator Noise Detection via 2D EGM Curves
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Solution Overview
Problem
Existing active implantable medical devices for monitoring heart rate and administering electrical pulses to treat heart arrhythmia are prone to false detections due to external noise, leading to inappropriate defibrillation shocks and potential harm to patients, with current filtering techniques not optimally addressing sensitivity issues, especially when noise originates from the lead.
Innovation Solution
The proposed solution enhances noise detection sensitivity by analyzing the variation in a geometrical descriptor of combined endocardial electrogram signals, using a 2D characteristic curve to differentiate between cardiac and extracardiac signals, and statistically analyzing amplitude variations to distinguish between monomorphic and polymorphic tachyarrhythmia, thereby preventing inappropriate therapies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional filtering techniques are used to detect extracardiac noise, then false detections are reduced, but noise detection sensitivity remains insufficient, especially when noise originates from the lead
Solution Approach 1:
The patent transitions from analyzing single-channel EGM signals to analyzing 2D characteristic curves formed by combining multiple EGM channels. This dimensional expansion enables the device to capture spatial relationships between signals, improving noise detection sensitivity by identifying extracardiac noise through its distinctive 2D geometric patterns while maintaining reliability through comprehensive signal analysis
Solution Approach 2:
The patent introduces geometrical descriptors (area, perimeter, circularity, aspect ratio) as new parameters to characterize 2D characteristic curves. By monitoring changes in these geometric parameters, the system can detect extracardiac noise with higher sensitivity while distinguishing it from genuine cardiac signals, thereby resolving the contradiction between detection sensitivity and false detection rate
2Reliability
If the device administers defibrillation shocks to treat detected tachyarrhythmia, then life-threatening arrhythmias are treated, but inappropriate shocks cause severe pain and potential harm to the patient
Solution Approach 1:
The patent performs preliminary analysis of 2D characteristic curves and geometrical descriptors before administering defibrillation therapy. By evaluating the geometric properties of the characteristic curves in advance, the system can distinguish genuine tachyarrhythmia from extracardiac noise, ensuring that defibrillation shocks are only delivered when truly indicated and preventing harmful inappropriate therapy
Solution Approach 2:
The system continuously monitors and analyzes 2D characteristic curves and geometrical descriptors, using this feedback to dynamically adjust therapy delivery decisions. This closed-loop approach ensures that defibrillation shocks are administered only when the geometric analysis confirms genuine tachyarrhythmia, thereby preventing inappropriate therapy while maintaining reliable treatment of life-threatening arrhythmias
Data Source
AI summary
An active implantable medical device includes a detection electrode and a pulse generator. The pulse generator is configured to collect via the detection electrode at least two EGM signals, combine the EGM signals into two time components, and combine the components into a single 2D parametric characteristic representing the cardiac cycle. During a tachyarrhythmia episode, the device measures stores values of a cycle-to-cycle variation in an amplitude of the at least one of the EGM signals, distributes the amplitude variation values into a plurality of classes, each class corresponding to an amplitude interval, and analyzes a size of each of the plurality of classes to deliver at least one of an indicator of suspicion of an artifact of extracardiac origin or an indicator of a type of tachyarrhythmia selectively as a function of at least one predetermined criterion applied to the distribution of the amplitude variation values.