Local Pulse Wave Velocity estimation using Magnetic Plethysmograph

A survey on signals and systems in ambulatory blood pressure monitoring using pulse transit time

Abstract: Blood pressure monitoring based on pulse transit or arrival time has been the focus of much research in order to design ambulatory blood pressure monitors. The accuracy of these monitors is limited by several challenges, such as acquisition and processing of physiological signals as well as changes in vascular tone and the pre-ejection period. In this work, a literature survey covering recent developments is presented in order to identify gaps in the literature. The findings of the literature are classified according to three aspects. These are the calibration of pulse transit/arrival times to blood pressure, acquisition and processing of physiological signals and finally, the design of fully integrated blood pressure measurement systems. Alternative technologies as well as locations for the measurement of the pulse wave signal should be investigated in order to improve the accuracy during calibration. Furthermore, the integration and validation of monitoring systems needs to be improved in current ambulatory blood pressure monitors.

Simultaneous analysis system for blood pressure and flow using photoplethysmography and ultrasonic-measurement-integrated simulation

Abstract: We developed a simultaneous analysis system for blood pressure and flow using photoplethysmography and ultrasonic-measurement-integrated simulation. The validity of the system was confirmed by analysis of blood flow field in a carotid artery and corresponding wave intensity (WI) values.

A Review of Methods for Non-Invasive Heart Rate Measurement on Wrist

Abstract: When evaluating general health condition on a patient, heart rate is an essential indicator as it is directly representative of the cardiac system state. Continuous measurement methods of heart rate are required for ambulatory monitoring involved in preliminary diagnostic indicators of cardiac diseases or stroke. The growing number of recent developments in wearable devices is reflective of the increasing demand in wrist-worn activity trackers for fitness and health applications. Indeed, the wrist represents a convenient location in terms of form factor and acceptability for patients. While most commercially-available devices are based on optical methods for heart rate measurement, others methods were also developed, based on various physiological phenomena. This review is focused on heart rate measurement methods located on forearm and more specifically on the wrist. For each method, the physiological mechanism involved is described, and the associated transducers for bio-signal acquisition as well as practical developments and prototypes are presented. Methods are discussed on their advantages, limitations and their suitability for an ambulatory use. More specifically, the superposition of motion artefacts over the signal of interest is one of the largest drawbacks for these methods, when used out of laboratory conditions. As such, artefact reduction techniques proposed in the literature are also presented and discussed.

Development of a Biotechnical Magnetopletysmography System for Monitoring Respiratory Rate and Heart Rate

Abstract: Sleep breathing disorder is a pathological condition characterized by changes in respiratory parameters, which includes obstructive sleep apnea syndrome, which, according to modern research, is associated with cardiovascular diseases. The high prevalence of this pathology and the lack of practical possibility to perform an in-depth examination of all potentially needy people necessitates the development of new diagnostic principles. In this article, the method of magnetic plethysmography as a noninvasive method of diagnostics of obstructive sleep apnea syndrome was considered. The model of biotechnical system was designed and manufactured, taking into account the requirements for ergonomics and low cost, the software for data reception and visualization was developed, an algorithm for automatic registration of respiratory movements frequency was proposed, and the product was tested. According to the results of the research, the performance of the product was proven: the ability to register respiratory wave from the thoracic and abdominal surface, the selection of respiratory rate and heart rate, nighttime sleep monitoring, the ability to detect apnea episodes, the ability of the algorithm to automatically register respiratory rate. It is concluded that the biotechnical system can be used for screening patients with obstructive sleep apnea syndrome and needs further development.

Expert consensus document on arterial stiffness : methodological issues and clinical applications. Commentary

Abstract: In recent years, great emphasis has been placed on the role of arterial stiffness in the development of cardiovascular diseases. Indeed, the assessment of arterial stiffness is increasingly used in the clinical assessment of patients. Although several papers have previously addressed the methodological issues concerning the various indices of arterial stiffness currently available, and their clinical applications, clinicians and researchers still report difficulties in selecting the most appropriate methodology for their specific use. This paper summarizes the proceedings of several meetings of the European Network for Non-invasive Investigation of Large Arteries and is aimed at providing an updated and practical overview of the most relevant methodological aspects and clinical applications in this area.

Expert consensus document on arterial stiffness: methodological issues and clinical applications

Abstract: In recent years, great emphasis has been placed on the role of arterial stiffness in the development of cardiovascular diseases. Indeed, the assessment of arterial stiffness is increasingly used in the clinical assessment of patients. Although several papers have previously addressed the methodological issues concerning the various indices of arterial stiffness currently available, and their clinical applications, clinicians and researchers still report difficulties in selecting the most appropriate methodology for their specific use. This paper summarizes the proceedings of several meetings of the European Network for Non-invasive Investigation of Large Arteries and is aimed at providing an updated and practical overview of the most relevant methodological aspects and clinical applications in this area.

Assessment of Arterial Distensibility by Automatic Pulse Wave Velocity Measurement: Validation and Clinical Application Studies

Abstract: Pulse wave velocity is widely used as an index of arterial distensibility. The aim of this study was to evaluate the accuracy of a new automatic device to measure it and then to analyze the major determinants of pulse wave velocity by application of this device in a large population. We evaluated the accuracy of on-line and computerized measurement of pulse wave velocity using an algorithm based on the time-shifted and repeated linear correlation calculation between the initial rise in pressure waveforms compared with the reference method (manual calculation) in 56 subjects. The results, analyzed according to the recommendations of Bland and Altman, showed a mean difference of -0.20 +/- 0.45 m/s for the mean carotid-femoral pulse wave velocity values (reference method, 11.05 +/- 2.58 m/s; automatic device, 10.85 +/- 2.44 m/s). The interreproducibility and intrareproducibility of measurements by each method were analyzed with the use of the repeatability coefficient according to the British Standards Institution. The interobserver repeatability coefficient was 0.947 for the manual method and 0.890 for the automatic, and intraobserver repeatability coefficients were 0.938 and 0.935, respectively. We evaluated the major determinants of the carotid-femoral pulse wave velocity measured by the automatic method in a separate study performed in 418 subjects of both sexes without any cardiovascular treatment or complication (18 to 77 years of age; 98 to 222 mm Hg systolic and 62 to 130 mm Hg diastolic pressure).(ABSTRACT TRUNCATED AT 250 WORDS)

Pulse wave analysis and arterial stiffness.

Abstract: Assessment of the pulse character is one of the earliest recorded medical skills, but objective recordings of the pulse waveform--sphygmography--emerged only in the nineteenth century. This technique fell into disuse with the advent of the sphygmomanometer, but interest has recently been rekindled with the introduction of computer technology and applanation tonometry. Pulse wave analysis (PWA) is a technique that allows the accurate recording of peripheral pressure waveforms and generation of the corresponding central waveform, from which the augmentation index and central pressure can be derived. In clinical studies, we have shown that PWA is a highly reproducible technique and easy to apply. Together with ECG-gated assessment of pulse wave velocity, also using PWA, these measures provide important information about arterial stiffness. Stiffness may be partly under the functional control of the endothelium, which releases a number of vasoactive mediators, as well as being structurally determined. Increased stiffness is associated with most cardiovascular risk factors and established atherosclerosis. However, increased stiffness may be more than a marker for occult atheroma. It may be involved in the pathogenesis of cardiovascular disease by a number of mechanisms. Assessment of stiffness, perhaps using PWA, may therefore provide better risk assessment and allow treatment to be targeted to those most in need.