Implantable Cardiac Device Overdetection Analysis
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Solution Overview
Problem
Implantable cardiac devices face challenges in accurately classifying cardiac rhythms due to overdetection of cardiac signals, which can lead to incorrect heart rate calculation and inappropriate therapy decisions.
Innovation Solution
The implementation of methods and devices that analyze the apparent width of detected events to identify overdetection, using techniques such as setting a QRS Width Count Limit and pattern recognition to correct data and improve analytical accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the device uses standard detection methods to identify cardiac events, then it can detect cardiac signals, but it may produce overdetection errors leading to incorrect heart rate calculation
Solution Approach 1:
The patent applies preliminary action by establishing a QRS width count limit before detecting cardiac events. The device pre-determines an expected width range for valid QRS complexes and uses this criterion to filter detections in advance, preventing overdetection errors before they affect heart rate calculation accuracy.
Solution Approach 2:
The patent introduces QRS width analysis as an intermediary criterion between signal detection and heart rate calculation. By measuring and comparing the width of detected QRS complexes against a predetermined limit, the device creates an additional verification layer that mediates between raw detections and final rate determination, eliminating overdetections.
2Loss of information
If the device detects all cardiac signal events, then it captures comprehensive cardiac activity data, but it may include false detections from noise leading to incorrect therapy decisions
Solution Approach 1:
The patent applies local quality by focusing detection criteria specifically on the QRS complex width characteristic rather than treating all cardiac signals uniformly. By identifying and measuring the specific width property of QRS complexes and comparing against a predetermined limit, the device selectively validates detections based on this local characteristic, filtering out noise-induced false detections while preserving true cardiac events.
Solution Approach 2:
The patent uses parameter changes by establishing a predetermined QRS width limit as a detection criterion. The device measures the width parameter of each detected QRS complex and compares it against this threshold parameter, changing from simple presence detection to parameter-based validation, thereby distinguishing true cardiac signals from noise.
Data Source
AI summary
Methods, systems, and devices for signal analysis in an implantable cardiac device such as an implantable cardioverter defibrillator. In illustrative examples, captured data including detected events is analyzed to identify likely overdetection of cardiac events. Analysis of the apparent width of detected events is used to determine whether overdetection is occurring. If overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data.