Implantable Cardiac Signal Filtering for Adaptive R-Wave Sensing
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Solution Overview
Problem
Existing implantable medical devices (IMDs) face challenges in accurately filtering cardiac signals due to varying electrophysiological properties among patients and changes over time, leading to incorrect signal interpretation and interference from noise sources, which affects R-wave sensing and arrhythmia detection.
Innovation Solution
A system with multiple band pass filters and a processor that analyzes filtered signals to determine the optimal filter setting based on individual-specific electrocardiogram signals, optimizing noise attenuation while preserving R-wave amplitude, using scoring criteria to select the most suitable filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed filter settings are used in IMD, then device complexity is reduced, but measurement precision of cardiac signals deteriorates due to varying electrophysiological properties among patients
Solution Approach 1:
The patent implements dynamic filter settings that automatically adapt to each patient's specific electrophysiological characteristics. The system evaluates multiple filter configurations (different cutoff frequencies and filter orders) and selects the optimal settings based on the patient's signal characteristics, transforming static filter parameters into dynamic, patient-specific configurations that maintain measurement precision without excessive complexity
Solution Approach 2:
The system changes filter parameters (cutoff frequencies, filter orders) based on patient-specific signal analysis. By evaluating how different parameter combinations affect signal quality metrics such as R-wave detection accuracy and noise attenuation, the system optimizes filter parameters for each individual patient, resolving the contradiction between simplified fixed settings and precise measurement requirements
2Object-affected harmful factors
If aggressive filtering is applied to remove noise, then noise attenuation is improved, but R-wave amplitude is reduced leading to incorrect signal interpretation
Solution Approach 1:
The system applies filtering actions selectively rather than uniformly. It evaluates multiple filter configurations with varying degrees of aggressiveness and selects the optimal level of filtering that achieves sufficient noise attenuation while preserving R-wave amplitude. This partial action approach avoids both insufficient filtering and excessive filtering that would distort the signal
Solution Approach 2:
The system uses feedback mechanisms to evaluate filter performance based on signal quality metrics. By monitoring how different filter settings affect R-wave detection accuracy and noise attenuation, the system adjusts filter parameters to achieve the optimal balance between noise removal and signal preservation, ensuring correct signal interpretation
3Adaptability or versatility
If multiple filter configurations are evaluated to optimize performance, then adaptability to individual patients is improved, but device complexity and computational requirements increase
Solution Approach 1:
The patent segments the filter evaluation process into discrete, manageable configurations. Instead of continuously varying filter parameters, the system evaluates a finite set of predefined filter configurations (specific cutoff frequencies and filter orders), making the adaptation process more tractable and less complex while still achieving patient-specific optimization
Solution Approach 2:
The system performs self-service by automatically evaluating multiple filter configurations and selecting the optimal settings based on the patient's signal characteristics without requiring external intervention. This automated self-optimization reduces the complexity burden on clinicians and patients while achieving high adaptability to individual needs
Data Source
Figure 1A~1B
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AI summary
A system and a method include an implantable medical device (IMD) (14, 100, 300) having one or more inputs (302) configured to receive one or more sensed signals (303) from one or more electrodes (305). A plurality of filters (304a, 304b, 304c) are configured to filter the one or more sensed signals (303) and output a plurality of filtered signals (310a, 310b, 310c). Memory (308) is configured to store program instructions. A processor (306), when executing the program instructions, is configured to receive the plurality of filtered signals (310a, 310b, 310c), and analyze the plurality of filtered signals (310a, 310b, 310c) to determine a desired one of the plurality of filters (304a, 304b, 304c).