Ultra-High Frequency EKG Signal Processing for Cardiac Diagnosis
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Solution Overview
Problem
Current EKG monitors are limited by their frequency range and dynamics, unable to effectively analyze and interpret ultra-high frequency electrical activities above 250 Hz, which restricts the diagnosis of heart abnormalities and the assessment of sudden cardiac death risks.
Innovation Solution
A method and apparatus for processing EKG signals by selecting a frequency range above 250 Hz, calculating and averaging amplitude or power envelopes, and converting them into numerical parameters to enhance signal-to-noise ratio, allowing for the detection of ultra-high frequency oscillations and their time and location of activation in the myocardium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frequency range of EKG monitors is extended above 250 Hz, then the ability to detect ultra-high frequency oscillations and diagnose heart pathologies is improved, but the signal-to-noise ratio deteriorates due to increased noise in the ultra-high frequency range
Solution Approach 1:
The patent applies preliminary action by calculating amplitude or power envelopes of the EKG signal in the ultra-high frequency range before averaging them with respect to R wave positions. This preprocessing step prepares the signal in advance to enhance the signal-to-noise ratio, allowing effective detection of ultra-high frequency oscillations above 250 Hz while mitigating the inherent noise problem in this frequency range.
2Measurement precision
If amplitude or power envelopes are calculated and averaged with respect to R wave positions, then the signal-to-noise ratio is improved, but the complexity of the signal processing method increases
Solution Approach 1:
The patent applies segmentation by dividing the EKG signal processing into distinct stages: first selecting the ultra-high frequency range above 250 Hz, then calculating amplitude or power envelopes, and finally averaging these envelopes with respect to R wave positions. This segmented approach breaks down the complex processing task into manageable steps, making the sophisticated signal processing more systematic and implementable while achieving improved signal-to-noise ratio.
3Device complexity
If the frequency range is limited to up to 250 Hz, then the device complexity and processing requirements are reduced, but the ability to interpret ultra-high frequency electrical activities and diagnose heart abnormalities is lost
Solution Approach 1:
The patent applies the taking out principle by extracting the ultra-high frequency component above 250 Hz from the complete EKG signal. This is achieved through frequency selection that isolates the ultra-high frequency range, allowing the system to focus processing resources on this specific frequency band while still capturing the critical ultra-high frequency electrical activities that contain diagnostic information about heart pathologies.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the non-invasive diagnosis of heart pathologies and risk assessment for sudden cardiac death by providing new insights into myocardial electrical activity, improving the interpretation of ultra-high frequency oscillations and enhancing the detection of cardiac abnormalities.
Implementation Method 1
amplitude or power envelopes of the EKG signal are calculated using Hilbert
Implementation Method 2
the averaged amplitude or power envelopes of the EKG signal within the interval of 300 ms before and 600 ms after the Rm of R wave position of QRS complex from the individual channels are converted to a series of numerical parameters
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C
AI summary
A method of measuring and analyzing the ultra high frequency EKG is performed by measuring the EKG within the frequency range above 250 Hz with a dynamic range of at least 100 dB. In the UHF EKG signal positions of Rm of R wave in QRS complex of EKG are detected on the time axis and the EKG signal is converted to amplitude or power envelopes, the amplitude or power envelopes frequency range is anywhere within the limits from 0,2 Hz to at least 500 Hz. From these envelopes the amplitude and time numerical parameters that describe the myocardium depolarization inhomogeneity and electric myocardium dyssynchrony are determined, and these parameters are used for selecting the patients for multi-chamber stimulators implementation and optimization of their setting.