Heartbeat Measurement Research Articles

Remote sensing of vital sign of human body with radio frequency

Medical technology has improved remarkably in the field of health monitoring over the past few decades, becoming more sophisticated and less invasive as the years progress. Now, non-contact measurement of respiration and heartbeat with microwave Doppler radar phase modulation, offers an attractive alternative to commonly prescribed chest strap monitors. To monitor the vital signs an unmodulated radio frequency signal is transmitted toward the human body, where it is phase-modulated by the periodic physiological movement and reflected back to the receiver. The radar receiver captures the reflected signal and demodulates it to extract the vital sign signal components. The reflected signal from the body depends on the radar cross section (RCS) of body. In this paper the RCS of human body is measured in the X-band (8–12 GHz). There are several advantages to a noncontact measurement method: physically, it neither confines nor inhibits the subject and does not cause discomfort or skin irritation as electrodes and straps do. By measuring heartbeats, this technology can also be used to detect a person’s presence, search-and-rescue for earthquake or fire victims and border patrol. It has also attracted the interest of organizations requiring high security, such as see-through- wall radar and airport security monitoring.

A novel unconstrained cardiorespiratory monitoring system during sleep

ABSTRACTAs one of the basic means of assessing human health conditions, cardiorespiratory monitoring during sleep has been widely used in diagnosis of sleep disorders. In this paper, a novel method for unconstrained and non-invasive measurement of respiration and heartbeat is proposed. The method is based on the intelligent combination of two sensor systems for respiratory and pulse monitoring. In order to wear comfortable, polyvinylidene fluoride (PVDF) film was taken as the sensor material. For improving the sensor sensitivity, a “double-sided arch” spring and a “thin-shell” spring were designed as the substrate of respiratory sensor and pulse sensor, respectively. To obtain clear cardiorespiratory responses from the sensor probe, hardware filter circuit is applied for further data filtering. Relative cardiorespiratory signal parameters such as respiratory cycle (RC) and heart rate (HR) could be displayed by LabVIEW. The fabrication steps and some experiments results for human monitoring system are described. The results show that respiration and pulse signal can be obtained accurately and the method lays the foundation for medical diagnosis.

Noncontact measurement of body position and vital information using airborne ultrasound

Because of a growing need for unconstrained medical monitoring for unobtrusively observing individuals in a living space, we have been studied about non-contact measurement of vital information such as respiration and heartbeat using airborne ultrasound. In previous study, the measurement system of small displacement using the M-sequence-modulated signal and tracking phase difference of reflected signals from the target has been proposed. The measurement of respiration and heartbeat of the target in a standing position using a pair of the loudspeaker and the microphone has also been performed. However, body position cannot be measured using a pair of the loudspeaker and the microphone because the system can measure the distance to the body only. In this paper, we describe a basic study of the measurement of body position, respiration, and heartbeat. In the system, using microphone array, body position was estimated by synthetic aperture processing. In addition, small body-surface velocity by respiration a...

A System for the Comprehensive Quantification of Real-Time Heartbeat Activity

Heartbeat can reflect the dynamics of the heart control system, and it is also a commonly used index in health monitoring, exercise load calculation and psycho-physiological arousal quantification. This paper fuses three heartbeat measures, i.e. the running mean, the range of local Hurst exponents and the relative fluctuation, to construct a system that can automatically quantify the heartbeat activity both from its static aspect and from its dynamic aspect in a real-time manner. Experiments show that the system can reveal the heartbeat arousal difference between physically relaxed status and exercise-loaded status. When the affective heartbeat data in literature are quantified by this system, the results also show the capability of the system to illustrate psycho-physiological arousal.

Heart rate measurement and electrical pulse signal analysis for subjects span of 20–80 years

The preliminary research constructs the heart beat or pulse measurement for medical science. The electrical pulse signal analysis that supports one significant clinical study. The research prototype focuses the pulse rate and analysis system which consist of hardware and software parts. The hardware uses the ATMEGA 2560 ADK R3 for processing the input optical sensors, output result to LCD, and record data into SD memory card. The software as embedded algorithm is designed for controlling the input/output parts. Research techniques are applied in term of analog to digital converter, I2C, and data grouping.The 40 subjects are informed consent and measured with ethical research. Experimental result explains the subject behaviors with maximum/minimum pulse values, patterns, and similarity three groups. The distinctive point of medical and health science prototype is accuracy, durability, low power consumption, and cheaper price.

A Heartbeat and Temperature Measuring System for Remote Health Monitoring using Wireless Body Area Network

This paper presents the design and development of a microcontroller based heartbeat and body temperature monitor using fingertip and temperature sensor. The device uses the optical technology to detect the flow of blood through the finger and offers the advantage of portability over conventional recording systems. However, wireless body area network based remote patient monitoring systems have been presented with numerous problems including efficient data extraction and dynamic tuning of data to preserve the quality of data transmission. Evaluation of the device on real signals shows accuracy in heartbeat measurement, even under intense physical activity. This paper presents these challenges as well as solution to these problems by proposing an architecture which allows a network to be formed between the patient and doctor in order to enable remote monitoring of patient by analyzing the data of patient. The device consists of sensors which are used to measure heartbeat as well as body temperature of a patient and it is controlled by a central unit. The readings from these sensors are further processed and sent via GSM module to a remote location where it is displayed on cell phone. The optical heartbeat sensor counts the heartbeat per minute and temperature sensor measures the temperature from the body and both the measured data are sent to a receiving end utilizing wireless technology where the data is displayed in a cell phone for further processing and patient care. Moreover, the superiority of this device is shown in comparison to traditional system.

DESIGN AND IMPLEMENTATION OF UBIQUITOUS HEALTH SYSTEM (U-HEALTH) USING SMART-WATCHES SENSORS

Abstract. Today as diseases grow rapidly, the responsibilities of the health clinics in giving services to patients increase and patients have to be more monitored and controlled. Remote systems of monitoring patients result in reducing cost, ease of movement, and also persistent control of patients by their doctors, so that patient can be monitored without need to go to the clinic. Recent advances in the field of ubiquitous sciences as well as using smartphones have resulted in increasingly use of this devices in remote monitoring of patients. The aim of this paper is to design and implement a ubiquitous health system using smartphones and sensors of smart-watches. This is accomplished through the information sent to the smartphone from the sensors of the watch, e.g. heart beat measurement sensor and ultraviolet ray. Then, this information is analyzed in the smartphone and some information based on the position of the patient and the path of him/her using GIS analyses as well as the information about the health level of the patient is sent to the doctor via SMS or phone call. Unnatural heart beats can be resulted in diseases such as Heart Failure and Arterial Fibrillation. With the approach adopted in this study, the patient or the doctor could be aware of these diseases at any time. The proposed approach is a low cost, without need to complex and resilient equipment, system in ubiquitous health that does not limit the movement of the patient.

Simultaneous Measurement of Breathing and Heartbeat using Airborne Ultrasound in a Standing Position

We have been studied about non-contact measurement of respiration and heart rates. In previous papers, the measurement system of small velocity using the M-sequence-modulated signal and phase difference of reflected signals from the target has been proposed. In this paper, we describe measurement of breathing and heartbeat in a standing position using the proposed method. Body-surface velocities by breathing and heartbeat could be observed respectively when the volunteer was breathing and holding the breath. In addition, measured velocity of breathing volunteer includes the component by heartbeat. It is considered that it has possibility to measure breathing and heartbeat concurrently.

柔軟面状触覚センサを用いた呼吸と心拍の無拘束計測

柔軟面状触覚センサを用いた呼吸と心拍の無拘束計測

Basic study of breathing and heartbeat measurement system using Kinect

Basic study of breathing and heartbeat measurement system using Kinect

Determination of locations on a tactile sensor suitable for respiration and heartbeat measurement of a person on a bed.

Sleep monitoring systems that can be used in daily life for the assessment of personal health and early detection of diseases are needed. To this end, we are developing a system for unconstrained measurement of the lying posture, respiration and heartbeat of a person on a soft rubber-based tactile sensor sheet. The respiration and heartbeat signals can be detected from only particular locations on the tactile sensor, and the locations depend on the lying location and posture of the measured person. In this paper, we describe how to determine the measurement locations on the sensor. We also report a realtime program that detects the respiration rate and the heart rate by using this method.

A new method for the acquisition of arterial pulse wave using self-mixing interferometry

In this paper we present a technique based on self-mixing interferometry as a method for the acquisition and reconstruction of the arterial pulse wave. A modification of the classic fringe counting reconstruction algorithm is proposed to deal with some of the problems caused by biological tissue surface roughness, therefore allowing a reconstruction of the arterial displacement with a resolution of 400 nm. The traits of the arterial pulse wave have been retrieved with high detail, allowing their interpretation by a skilled practitioner. The heart beat measurements show a good agreement when compared to the readings of a commercial pulse-meter, therefore proving the versatility and the viability of the technique for the measurement of other cardiovascular signals.

Study of the relationship between the aerobic capacity (VO2 max) and the rating of perceived exertion based on the measurement of heart beat in the metal industries Esfahan.

Background and Objective:To establish a balance between work (physical exercise) and human beings, the aerobic capacity (VO2 max) could be used as a measure. Additionally, the subjective and physiological assessment could be applied as one of the methods for assessing physical exercise. The most commonly used tools for the assessment of fatigue during physical exercise include the Borg scale Rating of perceived Exertion (RPE) in relation to subjective symptoms and heart rate (HR) in relation to physiological symptoms. The study is aimed to investigate the relationship between the aerobic capacity and the RPE based on the measurement of heat rate (HR) of workers from the Metal Industries of Isfahan.Materials and Methods:The subjects were 200 male workers from metal components manufacturers in Isfahan selected by using random sampling based on statistic method. The subjects were examined by using ergometer in accordance with A strand 6 minutes cycle test protocol. Furthermore, the subjects were asked to rate their status based on the Borg rating scale at the end of each minute. Additionally, their heat rates were monitored and recorded automatically at the end of each minutes.Results:Statistical analysis showed that there was a significant relationship between the RPE and the aerobic capacity (VO2 max) (r = –0.904, P < 0.05). The results illustrated that there was a stronger correlation between HR and VO2 max (r = 0.991, P < 0.001). The regression analysis of the quadratic equation also indicated that there was also a significant relationship between the VO2 max and HR.Conclusions:The results indicated that there was a strong relationship between the RPE and VO2 max, as well as a greater correlation between HR and VO2 max. Therefore, the HR could be used as a Prediction measure to estimate VO2 max.

실시간 맥박 및 혈압 측정을 위한 폴리머 기판 압력센서 개발

In this study, we introduce a polymer(polyimide) based pressure sensor to measure real-time heart beat and blood pressure. The sensor have been designed with consideration of skin compatibility of material, cost effectiveness, manufacturability and wireless detection. The designed sensor was composed of inductor coils and an air-gap capacitor which generate self-resonant frequency when electrical source is applied on the system. The sensor was obtained with metalization, etching, photolithography, polymer adhesive bonding and laser cutting. The fabricated sensor was shaped in circular type with 10mm diameter and 0.45 mm thickness to fit radial artery. Resonant frequencies of the fabricated sensors were in the range of 91~96 MHz on 760 mmHg pressurized environment. Also the sensor has good linearity without any pressure-frequency hysteresis. Sensitivity of the sensor was 145.5 kHz/mmHg and accuracy was less than 2 mmHg. Real-time heart beat measurement was executed with a developed hand-held measurement system. Possibility of real-time blood pressure measurement was showed with simulated artery system. After installation of the sensor on skin above radial artery, simple real blood pressure measurement was performed with 64 mmHg blood pressure variation.

Measurement of Blood Pressure and Heart Beat Based on Sensors and Microcontrollers

As heart related diseases are increasing over days, a mandatory need for an accurate, affordable heart rate and blood pressure measurement is essentially required now a day. This paper illustrates the simulation of two devices used to measure the heart rate and the blood pressure. The two proposed designs are built using different type of sensors and the generated results are compared to those of the (HEM-907XL) device from OMRON company. The first proposed design is constructed using either infrared (IR) sensor or light dependent resistance (LDR) to measure the heart rate. On the other hand, the second design is constructed using either a group of strain gauge sensors, or a group of piezoelectric sensors to measure the blood pressure. One hundred human subjects of different ages between 25 and 70 years old are used to test both designs. The two designs are implemented using microcontroller (ATMEGA 16); for it is lower cost and high efficiency. A comprehensive study is conducted on the results using statistical analysis to verify the validity of both designs.

Development of Unconstrained Heartbeat and Respiration Measurement System With Pneumatic Flow

The management of health through daily monitoring of heartbeat and respiration signals is of major importance for early diagnosis to prevent diseases of the respiratory and circulatory system. However, such daily health monitoring is possible only if the monitoring system is physically and psychologically noninvasive. In this paper, an unconstrained method of measuring heartbeat and respiration signals, by using a thermistor to measure the air flows from the air mattress to an air tube accompanying the subject's heartbeat and respiration, is proposed. The SN ratio with interference by opening and closing of a door as environmental noise was compared with that obtained by the conventional condenser microphone method. As a result, the SN ratios with the condenser microphone method were 26.6 ± 4.2 dB for heartbeat and 27.8 ± 3.0 dB for respiration, whereas with the proposed method they were 34.9 ± 3.1 dB and 42.1 ± 2.5 dB, respectively.

Physical Working Principles of Medical Radar

There has been research interest in using radar for contactless measurements of the human heartbeat for several years. While many systems have been demonstrated, not much attention have been given to the actual physical causes of why this work. The consensus seems to be that the radar senses small body movements correlated with heartbeats, but whether only the movements of the body surface or reflections from internal organs are also monitored have not been answered definitely. There has recently been proposed another theory that blood perfusion in the skin could be the main reason radars are able to detect heartbeats. In this paper, an experimental approach is given to determine the physical causes. The measurement results show that it is the body surface reflections that dominate radar measurements of human heartbeats.

Motion Artifact Compensation for Wristwatch Type Photoplethysmography Sensor

Heart beat measurement is useful not just for medical use but also for daily healthcare monitoring and for sports. Photoplethysmography is an optical pulse measurement method that measures the variation of light absorption of the blood flow in capillary. Fingertip and earlobe, which are suitable places for this method, are not suitable for wearing sensors in daily life. Measurement at wrist will be more favorable. Technical difficulties of applying photoplethysmography measurement on wrist are: a) blood flow variation and change of sensor orientation caused by body motions, and b) low sensitivity compared to measurement at fingertips or earlobes because of the low capillary density in the tissue. We derived a transfer function that expresses the relationship between body acceleration and change in capillary blood flow based on a simple fluid dynamics model of artery and capillary. Preliminary experiments have shown that motion the artifacts can be reduced by subtracting the change of blood flow estimated from body acceleration. This method is different from conventional frequency filtering methods that do not consider the relationship between the body motion and the changes in the capillary blood flow. Furthermore, sensor head suspension mechanism has been employed in order to stabilize the sensor orientation with respect to the skin as well as the applied force on the skin.

Radiation dose exposure of patients undergoing 320-row cardiac CT for assessing coronary angiography and global left ventricular function

A 320-row multidetector CT provides the capability for prospective electrocardiogram (ECG)-gated coronary CT angiography (CTA) and tube current modulated cardiac function assessment (CFA). We assessed and compared the effective radiation dose of these two modes. On a prospective basis, we performed ECG-gated cardiac CT on 119 patients (87 were males). For heart rates (HRs) </=65 beats/min (bpm), we used one-heartbeat acquisition and half-scan reconstruction. HRs from 66 to 79 bpm and >/=80 bpm were scanned with either two or three heartbeats acquisitions, respectively. We used two types of scans. One type was based on a prospective ECG-gated CTA mode and the other using a tube current modulated CFA mode covering an entire R-R interval. The mean BMI of patients was 25.4 (range 18.8-49.3). Fifty-one patients (42.9 %) underwent CFA scanning, while the remaining 68 (57.1 %) had CTA. The majority of patients completed the scan in a single heartbeat (59.7 %). The mean dose of CTA mode at 65-85 % phase window for one and two heartbeats was 3.68 mSv (2.40-7.23) and 8.61 mSv (6.76-10.60), respectively. The mean dose of CFA mode for a single heartbeat measurement with dose modulation (25 % dose for CFA, and 100 % dose during 65-85 % phase window for CTA) was 6.32 mSv (4.69-8.89). CTA with prospective ECG-gating allows for acceptable image quality and radiation dose. HR reduction is mandatory to minimize radiation exposure. Global left ventricle function can be assessed with a single heartbeat within an acceptable radiation dose.

Heuristic Algorithm for Photoplethysmographic Heart Rate Tracking During Maximal Exercise Test

Photoplethysmography (PPG) is a non-invasive optical technique that can be used to quantify the arterial blood pulse rate. Signal corruption by motion artifacts limits the practical accuracy and applicability of instruments for monitoring pulse rate during intense physical exercise. This study develops and validates an algorithm, which is based on linear filtering and frequency-domain and heuristic analyses, for extracting the heart rate from a PPG signal in the presence of severe motion artifacts. The basis of the hearth beat frequency selection is the observed high harmonic content of movement artifact signals with respect to the PPG-derived heartbeat. The algorithm, implemented in an experimental PPG measurement device, is developed by analyzing a set of PPG data recorded from a group of athletes exercising on a treadmill. An extensive set of tests is carried out during maximal exercise tests on a treadmill to validate the proposed algorithm by comparison with a reference electrocardiography measurement system. The Bland-Altman method is used to compare and evaluate PPG signals. The accuracy of the heartbeat measurement is better than ± 6.5 beats per minute (bpm) ( ≤ 4.2 %) even under maximal exercise conditions.