Angular Motion Sensor for Posture-Independent Cardiac Monitoring

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Solution Overview

Problem

Existing non-invasive cardiac monitoring techniques, such as echocardiography and electrocardiography, face limitations in ambulatory monitoring due to complexity, invasive nature, and posture-dependent measurements, while prior art methods like ballistocardiography are affected by subject posture and incomplete measurement of heartbeat characteristics.

Innovation Solution

A system utilizing a sensor of angular motion to obtain angular ballistocardiograph signals, which are processed to generate output parameters indicative of cardiac operation, using microelectromechanical gyroscopes that are insensitive to posture and location, enabling accurate and portable cardiac monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If linear ballistocardiograph measurement is used, then heart motion can be measured, but measurement is strongly affected by subject posture

Engineering Contradiction:
Improveheart motion measurementVSAvoidposture independence
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent transitions from linear acceleration measurement (one dimension) to angular motion measurement (rotational dimension). By measuring angular motion around multiple axes instead of linear acceleration along spatial axes, the system captures heart-induced rotational movements that are independent of gravitational effects and subject posture, thereby resolving the contradiction between measurement precision and posture independence.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If echocardiography is used, then noninvasive cardiac imaging is achieved, but complex immobile equipment is required

Engineering Contradiction:
ImproveinvasivenessVSAvoidequipment complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical imaging systems (echocardiography with ultrasound transducers and processing equipment) with a simple angular motion sensor system. By substituting mechanical/optical measurement systems with inertial sensing, the invention achieves noninvasive cardiac monitoring without requiring complex immobile equipment, thus resolving the contradiction between noninvasiveness and device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If electrocardiography with multiple electrodes is used, then accurate cardiac measurement is achieved, but proper electrode placement is challenging

Engineering Contradiction:
Improvecardiac measurement accuracyVSAvoidelectrode placement
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts the core measurement function from complex multi-electrode systems and implements it through a single angular motion sensor. By taking out the essential cardiac measurement capability and implementing it through angular ballistocardiography, the system achieves accurate cardiac parameter detection without requiring multiple electrodes and their precise placement, thereby resolving the contradiction between measurement precision and ease of operation.

Inventive Principle:
Principle #2Taking out (Extraction)

4Adaptability or versatility

If linear ballistocardiograph is used, then ambulatory monitoring is possible, but some heartbeat characteristics are not reliably measurable

Engineering Contradiction:
Improveambulatory capabilityVSAvoidheartbeat characteristic measurement
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent measures angular motion around multiple axes (pitch, roll, yaw) instead of linear acceleration along spatial axes. This dimensional change enables reliable measurement of heartbeat characteristics such as stroke volume and cardiac timing parameters during ambulatory monitoring, as rotational movements capture heart-induced chest wall motions more effectively than linear measurements, resolving the contradiction between ambulatory capability and measurement precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

The system provides accurate, posture-independent cardiac monitoring capable of detecting rotational heart movements, improving signal quality and enabling ambulatory monitoring with reduced complexity, allowing for reliable detection of cardiac parameters like stroke volume and atrial fibrillation.

Implementation Method 1

a sensor of angular motion configured to obtain an angular ballistograph signal indicative of rotational movement of a chest of a subject

Methodology Applied
Scientific EffectAngular motion sensing: Gyroscope

Data Source

PatentEP3043712B1Heart monitoring system
Publication Date: 2021.10.27 MURATA MFG CO LTD
  • EP3043712B1 patent drawingFigure 1~3
  • EP3043712B1 patent drawingFigure 4~6
  • EP3043712B1 patent drawingFigure 5

AI summary

A device that includes a sensor of angular motion configured to obtain an angular ballistograph signal indicative of rotational movement of a chest of a subject. Signal processing means are configured to generate from this angular ballistocardiograph signal measured values of an output parameter, which is indicative of cardiac operation of the subject.