Ballistocardiographic Arrhythmia Detection via Accelerometer Signal Processing
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Solution Overview
Problem
Current methods for detecting nocturnal arrhythmias are invasive, inconvenient for patients, and may distort sleep phases, leading to inaccurate diagnoses and potential false arrhythmia detections.
Innovation Solution
A non-invasive system using a single ballistocardiographic signal to detect beat-to-beat times and relative stroke volume, processed to provide information on sleep disorders, stress, recovery, and sleep phases, allowing for the detection of nocturnal arrhythmias and their relationship to these physiological phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive measurement methods are used to detect nocturnal arrhythmias, then measurement precision is improved, but ease of operation and patient comfort deteriorate
Solution Approach 1:
The patent replaces invasive mechanical/electrical measurement systems (ECG electrodes, Holter monitors) with a non-invasive ballistocardiographic system that uses accelerometers to detect mechanical movements of the body caused by cardiac activity. This substitution maintains diagnostic capability while eliminating the discomfort and inconvenience of invasive methods.
Solution Approach 2:
The patent introduces ballistocardiography as an intermediary measurement method that indirectly detects cardiac electrical activity through mechanical movements. Instead of directly measuring electrical signals from the heart, the system measures the mechanical recoil and body movements caused by cardiac contraction, providing a non-invasive pathway to arrhythmia detection.
2Loss of information
If invasive monitoring devices are used during sleep, then diagnostic information is improved, but the sleep quality and natural sleep phases deteriorate
Solution Approach 1:
The patent replaces invasive monitoring equipment that disturbs sleep with a non-invasive ballistocardiographic system using accelerometers. This system captures cardiac-related mechanical movements during natural sleep without requiring skin contact or restrictive equipment, thereby preserving sleep quality while maintaining diagnostic information quality.
Solution Approach 2:
The system allows subjects to sleep naturally without external intervention or restrictive equipment. The accelerometers passively detect ballistocardiographic signals during undisturbed sleep, enabling the monitoring system to serve itself by capturing data during the subject's natural physiological state without requiring active participation or compliance from the subject.
3Measurement precision
If traditional ECG-based methods are used for arrhythmia detection, then measurement precision is improved, but device complexity and invasiveness increase
Solution Approach 1:
The patent replaces complex ECG-based measurement systems with a simpler ballistocardiographic system using accelerometers. By substituting electrical signal measurement with mechanical movement detection, the system reduces device complexity while maintaining arrhythmia detection capability through alternative physiological parameters.
Solution Approach 2:
The ballistocardiographic system using accelerometers serves multiple functions: it detects arrhythmias, monitors sleep phases, and tracks cardiac mechanical activity. This multi-functionality replaces the need for separate specialized devices, reducing overall system complexity while maintaining comprehensive diagnostic capability.
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 enables reliable and accurate detection of nocturnal arrhythmias without affecting the subject's sleep, providing detailed temporal information that facilitates improved diagnosis and understanding of arrhythmia occurrences during sleep.
Implementation Method 1
A ballistocardiographic signal has a characteristic form, which is based on the blood flowing up and down in the body. This signal, for example delay and details of the shape of the BCG signal can reveal cardiac dysfunction.
Implementation Method 2
As heart pumps blood, two mechanical effects may be measured: motion of the heart causes a recoil effect on the chest, and motion of the blood causes a recoil effect in whole body.
Implementation Method 3
Ballistocardiographic data indicates the extent of mechanical movements of a body that take place in response to the myocardial activity of the heart.
Data Source
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Figure 2
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AI summary
The present invention relates to a method and a system for providing temporal information on a subject. The method comprises obtaining a ballistocardiologic signal of the subject with an accelerometer and processing the ballistocardiologic signal to obtain at least a beat-to-beat time (TB2B) signal and a stroke volume (SV) signal. A filtered TB2B signal and a filtered SV signal are provided by filtering the respective signal tore move erroneous values not caused by heart beats. The method further comprises calculating a true HR signal from the filtered TB2B signal and calculating a true SV signal and a stroke volume variability (SVV) signal from the filtered SV signal. The true HR signal is filtered to detect abnormal heart beats and to separate them from normal heart beats,white the true SV and SVV signals are used as parameters to facilitate separation of the abnormal and normal heart beats. If abnormal heartbeats are detected, type of arrhythmia related to the detected abnormal heart beats is identified and temporal information on occurrence and type of the identified arrhythmia is provided to a user.