Aortic Pulse Wave Second Derivative Inflection Point Analysis
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Solution Overview
Problem
Existing biological state analysis techniques rely on detecting oscillations on the body trunk, which are limited in precision and require additional instruments for heart sound measurement, lacking objective and precise methods for analyzing cardiovascular system dynamics.
Innovation Solution
A biological state analyzer that differentiates aortic pulse waves twice to identify inflection points corresponding to heart sounds, allowing for the analysis of cardiovascular system dynamics without external measurement instruments, using inflection points to determine sympathetic nervous system activity and cardiovascular health.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If second derivative waveform analysis of aortic pulse wave is used, then measurement precision of cardiovascular dynamics is improved, but device complexity increases due to requiring differentiation processing
Solution Approach 1:
The patent replaces complex mechanical measurement instruments (stethoscopes, external sensors) with signal processing methods. By using mathematical differentiation (second derivative) of the aortic pulse wave signal to extract inflection points corresponding to heart sounds, the system achieves precise cardiovascular measurement without additional mechanical measurement devices.
Solution Approach 2:
The patent transforms the aortic pulse wave signal by applying second derivative processing to change its parameters. This mathematical transformation extracts inflection points that correspond to heart sound timing, converting a single waveform into multiple diagnostic parameters (inflection point positions, intervals) that reveal cardiovascular dynamics and sympathetic nervous system activity.
2Ease of operation
If inflection points are used to identify heart sounds, then ease of operation is improved by eliminating external instruments, but measurement precision may be affected by signal processing accuracy
Solution Approach 1:
The patent replaces external measurement instruments (stethoscopes, heart sound sensors) with computational analysis of the existing aortic pulse wave signal. The second derivative processing and inflection point detection algorithm substitute for mechanical heart sound detection, simplifying operation while maintaining measurement capability through mathematical transformation.
Solution Approach 2:
The patent creates a computational model (second derivative waveform) that copies and transforms the original aortic pulse wave signal. This copied and processed waveform contains inflection points that replicate heart sound timing information, allowing indirect but accurate measurement without direct heart sound sensing.
Data Source
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AI summary
A novel technique for analyzing a biological state is provided. A body trunk biological signal (aortic pulse wave) extracted from the back of a body trunk is differentiated twice. By using a resultant second derivative waveform, a waveform component of a maximum amplitude of a low frequency appearing as a result of switch of an amplitude from attenuation to amplification in transition from a contracting phase to a diastolic phase of a ventricle is specified in each period of the second derivative waveform. Inflection points are specified that appear before and after the maximum amplitude waveform component. A biological state is analyzed using information about each of the inflection points. The two inflection points obtained from a reference form of the second derivative waveform of the aortic pulse wave substantially agree in time phase with first heart sound and second heart sound (or an R wave and a T wave in an electrocardiogram) indicating the dynamic state of a cardiovascular system. This enables analysis of a biological state.