Pulse Wave Acquisition Research Articles

A Multi-channel System Architecture Design for Myocardial Infarction Prediction

Cardiac and cerebral infarctions represent the most perilous pathologies within the spectrum of cardiovascular and cerebrovascular diseases, with grave consequences following their onset. However, prompt diagnosis and treatment can substantially enhance the chances of successful rescue and avert severe outcomes. Therefore, the development of a non-invasive, low-cost, and easy-to-use cardiac and cerebral infarction prediction system for home and personal use bears considerable social and economic significance.The electrocardiogram (ECG), acupoint electrical signals, and pulse, as physiological signals, contain abundant information on human health status. Integrating the information from these three signals can offer a more comprehensive and accurate risk prediction of cardiovascular and cerebrovascular diseases in patients. This approach represents a promising avenue for advancing the field of healthcare and disease management.Firstly, we analyzed the myocardial infarction and cerebral infarction prediction system requirements. The research determines four pulse collection points, two ECG, and ten acupoint electricity collection points. Then, we completed the cardiovascular and cerebrovascular disease risk warning system’s overall architecture design and front-end scheme design of ECG, acupoint electricit and pulse wave acquisition. The system successfully collects data from the test subjects by connecting to the computer.

Wearable Multi-Channel Pulse Signal Acquisition System Based on Flexible MEMS Sensor Arrays with TSV Structure.

Micro-electro-mechanical system (MEMS) pressure sensors play a significant role in pulse wave acquisition. However, existing MEMS pulse pressure sensors bound with a flexible substrate by gold wire are vulnerable to crush fractures, leading to sensor failure. Additionally, establishing an effective mapping between the array sensor signal and pulse width remains a challenge. To solve the above problems, we propose a 24-channel pulse signal acquisition system based on a novel MEMS pressure sensor with a through-silicon-via (TSV) structure, which connects directly to a flexible substrate without gold wire bonding. Firstly, based on the MEMS sensor, we designed a 24-channel pressure sensor flexible array to collect the pulse waves and static pressure. Secondly, we developed a customized pulse preprocessing chip to process the signals. Finally, we built an algorithm to reconstruct the three-dimensional pulse wave from the array signal and calculate the pulse width. The experiments verify the high sensitivity and effectiveness of the sensor array. In particular, the measurement results of pulse width are highly positively correlated with those obtained via infrared images. The small-size sensor and custom-designed acquisition chip meet the needs of wearability and portability, meaning that it has significant research value and commercial prospects.

A robust and flexible pulse wave sensory array enabling real-time non-invasive blood pressure monitoring

Chronical cardiovascular decreases such as hypertension requires real-time and continuous monitoring of blood pressures (BPs). Pulse wave that contains critical and ample information on cardiovascular dynamics is a direct vital sign to extract BP and therefore an epidermal wearable device enabling real-time acquisition of pulse waves becomes necessary. In this work, we propose and study a flexible pulse wave sensory array aiming for real-time wearable pulse wave acquisition with robustness. A piezoelectric sensor together with a thin-film transistor-based sensor interface circuit is used to detect multiple pulse waveforms at the location of radial artery, which are input to a convolutional neural network for a deep-learning BP estimation model training. The estimated BPs are assessed by a correlation study with the BPs measured by conventional sphygmomanometers. Our study shows a reasonable accuracy of mean deviation and standard deviation of 2.84 ± 7.53 mmHg for systolic BP and 0.88 ± 7.06 mmHg for diastolic BP.

A Novel Multi-Dimensional Composition Method Based on Time Series Similarity for Array Pulse Wave Signals Detecting

Pulse wave signal sensed over the radial artery on the wrist is a crucial physiological indicator in disease diagnosis. The sensor array composed of multiple sensors has the ability to collect abundant pulse wave information. As a result, it has gradually attracted the attention of practitioners. However, few practical methods are used to obtain a one-dimensional pulse wave from the sensor array’s spatial multi-dimensional signals. The current algorithm using pulse wave with the highest amplitude value as the significant data suffers from low consistency because the signal acquired each time differs significantly due to the sensor’s relative position shift to the test area. This paper proposes a processing method based on time series similarity, which can take full advantage of sensor arrays’ spatial multi-dimensional characteristics and effectively avoid the above factors’ influence. A pulse wave acquisition system (PWAS) containing a micro-electro-mechanical system (MEMS) sensor array is continuously extruded using a stable dynamic pressure input source to simulate the pulse wave acquisition process. Experiments are conducted at multiple test locations with multiple data acquisitions to evaluate the performance of the algorithm. The experimental results show that the newly proposed processing method using time series similarity as the criterion has better consistency and stability.

A novel flexible pressure sensor array for depth information of radial artery

Pulse wave collection from multi-points of radial artery under different static pressures is an essential method to diagnose diseases. However, there are some problems in the currently-used measuring instruments. Single-type sensor has limitations to pulse wave acquisition. It is not enough to set three sampling points to detect variation trend of radial artery pulse wave. Adaptation to different wrist surfaces and mutual interference of sensors are neglected. This paper proposes a novel flexible compound pressure sensor array for measuring radial artery pulse wave to overcome the problems mentioned above. Our compound pressure sensor consists of a piezoelectric sensor and a piezoresistive sensor which are used to measure pulse wave and static pressure separately. A bending structure of the sensor could guarantee the signal intensity and prevent the occurrence of inverted waveform. In this study, poroelastic materials are used to achieve flexible connection and decrease interference among sensors. In addition, the amplitude characteristics of pulse wave in radial artery are described and the arrangement and size of the sensor array is designed based on statistical data. Anti-interference, repeatability and validation experiments are carried out to evaluate the performance of the sensor array. The results show that the flexible compound pressure sensor array not only reflects depth information of radial artery pulse wave under a wide range of static pressures, but also has good repeatability and anti-interference performance.

ARM-based Embedded Detection System of Cardiovascular Function Parameters

A cardiovascular function testing system was designed in platform which was built with ARM microprocessor s3c2440 and Linux system, to achieve pulse wave acquisition, feature extraction, index calculation and so on. This article mainly describes the hardware circuit, and describes the touchscreen driver, external ADC driver, and visualization QT-based applications in detail. The system is easy to use, with real-time, low power consumption. Compared with common cardiovascular function test instrument, the results shows that the system can better assess the cardiovascular function, expecially in several key indicators like subendocardial myocardial viability rate and augmentation index, the indicators show good correlations.

Automated oscillometric blood pressure and pulse-wave acquisition for evaluation of vascular stiffness in atherosclerosis

ObjectiveEvaluation of diagnostic accuracy of an oscillometry-based device (VascAssist) combining fully automated ankle-brachial index (ABI) and pulse-wave velocity (PWV) assessment for detection of peripheral arterial disease (PAD).Subjects and methods110 consecutive subjects including symptomatic PAD patients (n = 41) and healthy PAD-free participants (n = 69) were recruited. All subjects underwent standard manual Doppler-based ABI (sABI) and oscillometry-based automated ABI (aABI) measurements (VascAssist). Oscillometry by the VascAssist included central and peripheral PWV assessment. Additionally, arterial stiffness (AS) was evaluated by flow-mediated vasodilation (FMD) of the brachial artery in all patients. All symptomatic PAD patients underwent catheter angiography for endovascular intervention and post-interventional acquisition of sABI, aABI, PWV and FMD.ResultsSensitivity, specificity, PPV and NPV of aABI for detecting PAD was 73%, 100%, 100%, and 86% as compared to 80%, 96%, 92%, and 89% for sABI. Pearson-correlation for diabetics was r = 0.81; (P < .001) and for non-diabetics r = 0.77; (P < .001). Bland–Altman-analysis revealed a difference (95% CI) for diabetics of 0.09 (−0.22–0.4] and non-diabetics 0.022 [−0.25–0.295]. Weak correlation exists for FMD/AS analysis (pre-interventional R = 0.386, P = .043; post-interventional R = −0.06; P = .76) and significant increase of pre-/post-interventional PWV analysis (P < .001).ConclusionCombined automatic ABI and PWV acquisition with the VascAssist device showed excellent diagnostic accuracy for detection of PAD. Compared to FMD, AS analysis may serve as an investigator-independent (screening) tool for determination of functional vascular damage in atherosclerosis.

Accuracy of commercial devices and methods for noninvasive estimation of aortic systolic blood pressure a systematic review and meta-analysis of invasive validation studies.

Although compelling evidence has established the physiological and clinical relevance of aortic SBP (a-SBP), no consensus exists regarding the validity of the available methods/techniques that noninvasively measure it. The systematic review and meta-analysis aimed to determine the accuracy of commercial devices estimating a-SBP noninvasively, which have been validated by invasive measurement of a-SBP. Moreover their optimal mode of application, in terms of calibration, as well as specific technique and arterial site of pulse wave acquisition were further investigated. The study was performed according to the PRISMA guidelines; 22 eligible studies were included, which validated invasively 11 different commercial devices in 808 study participants. Overall, the error in a-SBP estimation (estimated minus actual value) was -4.49 mmHg [95% confidence interval (CI): -6.06 to -2.92 mmHg]. The estimated (noninvasive) a-SBP differed from the actual (invasive) value depending on calibration method: by -1.08 mmHg (95% CI: -2.81, 0.65 mmHg) and by -5.81 mmHg (95% CI: -7.79, -3.84 mmHg), when invasively and noninvasively measured brachial BP values were used respectively; by -1.83 mmHg, (95% CI: -3.32, -0.34 mmHg), and by 7.78 mmHg (95% CI: -10.28, -5.28 mmHg), when brachial mean arterial pressure/DBP and SBP/DBP were used, respectively. Automated recording of waveforms, calibrated noninvasively by brachial mean arterial pressure/DBP values seems the most promising approach that can provide relatively more accurate, noninvasive estimation of a-SBP. It is still uncertain whether a specific device can be recommended as 'gold standard'; however, a consensus is currently demanding.

Development a polymer-based electronic pulse diagnosis instrument for measuring and analyzing pulse wave velocity.

A novel pulse-diagnosis system was proposed in this study for measuring pulse wave velocities. In contrast with most conventional mechanical, rigid-type pulse diagnosis instruments such as pressure transducers and microactuators, a conductive elastic polymer was adopted as the sensor material. The soft and formability properties of such material enabled fabricating a flexible pulse diagnosis instrument. In addition, the flexible design was integrated with a contemporary, wrist-type pulse-wave acquisition system to ensure stable measurements. Closely related to the incidence of cardiovascular diseases, pulse wave velocity was analyzed in applications to verify the feasibility of this system. Regarding signal processing, the cun, guan, and chi pulse signals obtained through the data acquisition device were sent to the LabVIEW platform for reconstructing the pulse waveforms. Finally, the results of 20 measured samples were compared and analyzed to evaluate the level of system performance.

Development a polymer-based electronic pulse diagnosis instrument for measuring and analyzing pulse wave velocity.

A novel pulse-diagnosis system was proposed in this study for measuring pulse wave velocities. In contrast with most conventional mechanical, rigid-type pulse diagnosis instruments such as pressure transducers and microactuators, a conductive elastic polymer was adopted as the sensor material. The soft and formability properties of such material enabled fabricating a flexible pulse diagnosis instrument. In addition, the flexible design was integrated with a contemporary, wrist-type pulse-wave acquisition system to ensure stable measurements. Closely related to the incidence of cardiovascular diseases, pulse wave velocity was analyzed in applications to verify the feasibility of this system. Regarding signal processing, the cun, guan, and chi pulse signals obtained through the data acquisition device were sent to the LabVIEW platform for reconstructing the pulse waveforms. Finally, the results of 20 measured samples were compared and analyzed to evaluate the level of system performance.

Physical exercise, fitness and dietary pattern and their relationship with circadian blood pressure pattern, augmentation index and endothelial dysfunction biological markers: EVIDENT study protocol

BackgroundHealthy lifestyles may help to delay arterial aging. The purpose of this study is to analyze the relationship of physical activity and dietary pattern to the circadian pattern of blood pressure, central and peripheral blood pressure, pulse wave velocity, carotid intima-media thickness and biological markers of endothelial dysfunction in active and sedentary individuals without arteriosclerotic disease.Methods/DesignDesign: A cross-sectional multicenter study with six research groups.Subjects: From subjects of the PEPAF project cohort, in which 1,163 who were sedentary became active, 1,942 were sedentary and 2,346 were active. By stratified random sampling, 1,500 subjects will be included, 250 in each group.Primary measurements: We will evaluate height, weight, abdominal circumference, clinical and ambulatory blood pressure with the Radial Pulse Wave Acquisition Device (BPro), central blood pressure and augmentation index with Pulse Wave Application Software (A-Pulse) and SphymgoCor System Px (Pulse Wave Analysis), pulse wave velocity (PWV) with SphymgoCor System Px (Pulse Wave Velocity), nutritional pattern with a food intake frequency questionnaire, physical activity with the 7-day PAR questionnaire and accelerometer (Actigraph GT3X), physical fitness with the cycle ergometer (PWC-170), carotid intima-media thickness by ultrasound (Micromax), and endothelial dysfunction biological markers (endoglin and osteoprotegerin).DiscussionDetermining that sustained physical activity and the change from sedentary to active as well as a healthy diet improve circadian pattern, arterial elasticity and carotid intima-media thickness may help to propose lifestyle intervention programs. These interventions could improve the cardiovascular risk profile in some parameters not routinely assessed with traditional risk scales. From the results of this study, interventional approaches could be obtained to delay vascular aging that combine physical exercise and diet.Trial RegistrationClinical Trials.gov Identifier: NCT01083082

Photonic textiles for pulse oximetry

Biomedical sensors, integrated into textiles would enable monitoring of many vitally important physiological parameters during our daily life. In this paper we demonstrate the design and performance of a textile based pulse oximeter, operating on the forefinger tip in transmission mode. The sensors consisted of plastic optical fibers integrated into common fabrics. To emit light to the human tissue and to collect transmitted light the fibers were either integrated into a textile substrate by embroidery (producing microbends with a nominal diameter of 0.5 to 2 mm) or the fibers inside woven patterns have been altered mechanically after fabric production. In our experiments we used a two-wavelength approach (690 and 830 nm) for pulse wave acquisition and arterial oxygen saturation calculation. We have fabricated different specimens to study signal yield and quality, and a cotton glove, equipped with textile based light emitter and detector, has been used to examine movement artifacts. Our results show that textile-based oximetry is feasible with sufficient data quality and its potential as a wearable health monitoring device is promising.