Non-linear Heart Rate Adaptive Cardiac Artifact Filter
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Solution Overview
Problem
Conventional medical monitoring systems face challenges in accurately measuring impedance respiration signals due to the presence of cardiac artifacts, which can lead to false alarms and inaccurate respiration rate measurements.
Innovation Solution
A non-linear, heart rate adaptive, cardiac artifact filter is designed to remove frequency components corresponding to the heart rate from the impedance respiration signal, thereby filtering out cardiac artifacts and providing a more accurate representation of respiratory activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional filtering methods are used to remove cardiac artifacts from impedance respiration signals, then the filtering process becomes simpler, but measurement precision deteriorates due to inaccurate respiration rate measurements and false alarms
Solution Approach 1:
The filter dynamically adapts its cutoff frequency based on the detected heart rate. As the heart rate changes, the filter's characteristics change accordingly to maintain optimal artifact rejection. This is achieved by continuously monitoring the ECG signal to determine heart rate and adjusting the filter parameters in real-time, ensuring the filter remains effective across varying physiological conditions without requiring complex manual configuration.
Solution Approach 2:
The invention changes the filter parameters (specifically the cutoff frequency) based on the heart rate parameter. By establishing a relationship between heart rate and optimal filter cutoff frequency, the system automatically adjusts the filtering characteristics to match the patient's current cardiac state. This parameter adaptation allows the filter to effectively separate cardiac artifacts from respiratory signals across different heart rates while maintaining measurement precision.
2Device complexity
If a fixed frequency filter is used to remove cardiac artifacts, then device complexity is reduced, but reliability worsens due to inaccurate filtering when heart rate varies
Solution Approach 1:
The filter transitions from a static, fixed-frequency design to a dynamic system that automatically adjusts its characteristics based on real-time heart rate monitoring. The system continuously tracks heart rate variations through ECG analysis and correspondingly modifies the filter's cutoff frequency, ensuring reliable artifact rejection across the full range of physiological heart rates without requiring multiple pre-configured filter settings.
Solution Approach 2:
The adaptive filter design provides universal applicability across different heart rate conditions. Instead of requiring separate fixed filters for different heart rate ranges, a single adaptive filter structure can handle all heart rate variations by dynamically adjusting its parameters. This multi-functional capability enhances reliability across diverse clinical scenarios while avoiding the complexity of implementing multiple specialized filters.
3Device complexity
If cardiac artifacts are not filtered from impedance respiration signals, then device complexity is minimized, but measurement precision deteriorates leading to false alarms and inaccurate respiratory monitoring
Solution Approach 1:
The filter selectively extracts and removes the cardiac artifact frequency components from the impedance respiration signal while preserving the respiratory signal components. By identifying the characteristic frequency range of cardiac artifacts based on heart rate and systematically eliminating these specific frequency components, the filter cleans the signal without requiring complex reconstruction or multiple processing stages, achieving good signal-to-noise ratio improvement with moderate complexity.
Data Source
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AI summary
The present disclosure provides a non-linear, heart rate adaptive, cardiac artifact filter designed to reduce cardiac artifacts in a patient's impedance respiration signal. The patient's impedance respiration signal may be acquired using electrocardiogram ("ECG") sensors and may be impacted by the patient's cardiac activity. This impact occurs at a single dynamically changing frequency determined from heart rate measurement. The adaptive cardiac artifact filter can be used to filter unwanted cardiac artifacts from the impedance respiration signal to provide a more accurate representation of the patient's cardiac activity. A filtered impedance respiration signal can then be displayed or analyzed to further the monitoring and treatment of the patient. The heart rate adaptive, cardiac artifact filter may be implemented in a physiological monitoring device that may be, in turn, a part of a system.