Non-invasive Heart Rate Measurement Research Articles

A Non-Invasive Heart Rate Measurement Method Is Improved by Placing the Electrodes on the Ventral Side Rather Than the Dorsal in Loggerhead Turtles.

Heart rate measurement is an essential method for evaluating the physiological status of air-breathing diving animals. However, owing to technical difficulties, many marine animals require an invasive approach to record an electrocardiogram (ECG) in water, limiting the application of this approach in a wide range of marine animals. Recently, a non-invasive system was reported to measure the ECG of hard-shelled sea turtles by pasting the electrodes on the dorsal side of the shell, although the ECG obtained from the moving turtle contains noise produced by muscle contraction. Here, we report that clear ECGs can be obtained by placing the electrodes on the ventral side rather than the dorsal side in loggerhead sea turtles. Using our method, clearer ECG signals were obtained with less electrical noise, even when turtles are swimming. According to the anatomical features, the electrode position on the ventral side is closer to the heart than the dorsal side, minimizing the effects of noise generated by the skeletal muscle. This new biologging technique will elucidate the functioning of the circulatory system of sea turtles during swimming and their adaptabilities to marine environments. This article is part of the theme issue “Methods and Applications in Physio-logging.”

A non-invasive system to measure heart rate in hard-shelled sea turtles: potential for field applications.

To measure the heart rate of unrestrained sea turtles, it has been believed that a probe must be inserted inside the body owing to the presence of the shell. However, inserting the probe is invasive and difficult to apply to animals in the field. Here, we have developed a non-invasive heart rate measurement method for some species of sea turtles. In our approach, an electrocardiogram (ECG) was performed using an animal-borne ECG recorder and two electrodes-which were electrically insulated from seawater-pasted on the carapace. Based on the measured ECG, the heartbeat signals were identified with an algorithm using a band-pass filter. We implemented this algorithm in a user-friendly program package, ECGtoHR. In experiments conducted in a water tank and in a lagoon, we successfully measured the heart rate of loggerhead, olive ridley and black turtles, but not green and hawksbill turtles. The average heart rate of turtles when resting underwater was 6.2 ± 1.9 beats min-1 and that when moving at the surface was 14.0 ± 2.4 beats min-1. Our approach is particularly suitable for endangered species such as sea turtles, and has the potential to be extended to a variety of other free-ranging species. This article is part of the theme issue 'Measuring physiology in free-living animals (Part I)'.

A non-invasive heart rate measurement system using laser Doppler blood flowmetry with husbandry training of the masked palm civet (Parguma larvata)

Husbandry training (HT) is done to facilitate healthcare, treatment or animal research with zoo animals. At the Omuta City Zoo, HT of masked palm civets (Parguma larvata) is used to aid the taking of blood samples. With HT the burden on the animal can be remarkably reduced without the use of anesthesia. However, it is necessary to devise a blood sampling method using HT that reduces stress on the animals as much as possible. To devise such a stress-reducing method, quantitative assessments related to stress are needed. As heart rate increases with stress, we attempted to devise a non-invasive method for measuring heart rate. The attachment of sensors not only stresses the animal but also requires much effort from keepers. Therefore, a laser Doppler blood flowmeter (LDF) was embedded in the HT board, and an LDF and an algorithm to eliminate body motion artifacts were used in measurement attempts. As a result, a clear pulse wave was detected in some sections, and heart rate was calculated from the pulse wave.

Noninvasive Measurement of Heart Rate and Respiratory Rate for Perioperative Infants

A novel fiber optic sensor is designed with mesh microbenders for simultaneous perioperative measurement of heart rate (HR) and respiratory rate (RR) for infants. The feasibility of the mesh microbend fiber sensor was evaluated in ten infants, ranging from 1 to 12 months in a prospective cross-sectional observational study with the sensor placed under the subjects in the perioperative period. All the study subjects received standard intraoperative physiological monitoring of their vital signs. The high order harmonic sensing signals associated with other filtering methods are used for the removal of motion noise. The study results displayed good agreement in the measurement of HR and RR between the proposed microbend fiber sensor and the current standard physiological monitoring used in medical settings.

Distant Measurement of Plethysmographic Signal in Various Lighting Conditions Using Configurable Frame-Rate Camera

Abstract Videoplethysmography is currently recognized as a promising noninvasive heart rate measurement method advantageous for ubiquitous monitoring of humans in natural living conditions. Although the method is considered for application in several areas including telemedicine, sports and assisted living, its dependence on lighting conditions and camera performance is still not investigated enough. In this paper we report on research of various image acquisition aspects including the lighting spectrum, frame rate and compression. In the experimental part, we recorded five video sequences in various lighting conditions (fluorescent artificial light, dim daylight, infrared light, incandescent light bulb) using a programmable frame rate camera and a pulse oximeter as the reference. For a video sequence-based heart rate measurement we implemented a pulse detection algorithm based on the power spectral density, estimated using Welch’s technique. The results showed that lighting conditions and selected video camera settings including compression and the sampling frequency influence the heart rate detection accuracy. The average heart rate error also varies from 0.35 beats per minute (bpm) for fluorescent light to 6.6 bpm for dim daylight.

A Non Invasive Heart Rate Measurement System for Multiple People in the Presence of Motion and Varying Illumination

A real time non-invasive heart rate (HR) measurement system for multiple people in an image has been proposed in this paper. The data has been gathered using a webcam with different distances with the subjects under varying illumination conditions. The effect of motion of the subjects on HR measurement is also observed. The data is gathered from the face and cheeks are selected as the region of interest (ROI). RGB color model is used for processing. Fast Fourier transform is used to detect the peak frequency after band pass filtering. The green channel of RGB color model gives best HR measurement. The minimum percentage error of 3.1% is achieved in the presence of slow movement and multiple persons at the relative distance of 100 cm.

Effects of acute systemic administration of TiO2, ZnO, SiO2, and Ag nanoparticles on hemodynamics, hemostasis and leukocyte recruitment

It has been suggested that engineered nanomaterials (ENM), once arrived in the circulation, may affect the cardiovascular system. The aim of this in vivo study was to screen major cardiovascular effects of acute systemic administration of a panel of five nanomaterials, TiO2 anatase (NM-101), TiO2 rutile (NM-104), ZnO (NM-110), SiO2 (NM-200) and Ag (NM-300). Mice were anesthetized and the ENM were injected at a dose of 1 mg/kg via a catheter placed in the left femoral artery. Hemodynamic parameters were determined by invasive measurement of blood pressure and non-invasive measurement of heart rate. Ten minutes after injection of the ENM, the formation of light/dye-induced thrombi was assessed in the cremasteric microcirculation by intravital microscopy. In addition, the numbers of rolling, firmly adherent and transmigrated leukocytes were recorded in postcapillary cremasteric venules over a time period of 120 min after injection of ENM by intravital microscopy. The systemic administration of a single dose of the ENM tested did not dramatically alter hemodynamic parameters or affect early steps of leukocyte recruitment. However, the presence of circulating TiO2 anatase, but not of TiO2 rutile, SiO2, ZnO or Ag nanoparticles, significantly accelerated thrombus formation in the murine microcirculation. Moreover, TiO2 anatase but not TiO2 rutile nanoparticles increased murine platelet aggregation in vitro. Taken together, only one of the five systemically administered ENM, TiO2 anatase, affected hemostasis, whereas none of the ENM tested in this screening study dramatically modulated hemodynamic parameters or early steps of leukocyte recruitment.

A Comparison of Signal Processing Techniques for the Extraction of Breathing Rate from the Photoplethysmogram

The photoplethysmogram (PPG) is the pulsatile wave- form produced by the pulse oximeter, which is widely used for monitoring arterial oxygen saturation in patients. Various methods for extracting the breathing rate from the PPG waveform have been compared using a consistent data set, and a novel technique using autoregressive modelling is presented. This novel technique is shown to outperform the existing techniques, with a mean error in breathing rate of 0.04 breaths per minute. ULSE oximetry is frequently used in clinical situations for non-invasive measurement of heart rate and arterial oxygen saturation. It has been suggested that signal processing techniques can be used to extract the breathing rate from the photoplethysmogram (PPG), which is the pulsatile waveform produced by a pulse oximeter at one of its two wavelengths (red and infra-red). If this is possible, it would allow non- invasive measurement of breathing rate using a device (the pulse oximeter) that is already used in many clinical situations, and is known to cause a minimum of distress or inconvenience to the patient. A number of methods for deriving the breathing rate from the PPG have been suggested in the literature. Results from the assessment of these methods using a consistent data set are presented in this paper, allowing comparisons between the methods to be made. A new method using autoregressive (AR) modelling has also been developed, and is shown to perform better than the existing techniques. II. MATERIALS AND METHODS Seven records from the MIMIC database in the Physiobank archive (1) were identified for use in assessing the accuracy of the algorithms for the extraction of breathing rate. These records all contain both the PPG waveform, and a synchronous respiratory waveform (believed to be obtained by nasal ther- mistry) for use as a reference. Two five-minute sections from each of the records were identified for use in the tests, resulting in a dataset consisting of fourteen five-minute sections from seven individuals. Sections were identified by looking for the

Noninvasive Heart Rate Measurement Using a Digital Egg Monitor in Chicken and Turkey Embryos

Abstract Monitoring the life status of a developing embryo is very useful, especially during last days of incubation when hatching could potentially be assisted if deemed necessary. A commercially available digital egg monitor (Buddy, Vetronic Services, Devon, UK) uses noninvasive methodology to monitor the heart rate of an embryo by measuring the amount of infrared light absorbed by embryonic blood. Thirty specific pathogen-free (SPF) chicken eggs (29 fertile) were incubated at 37.8 ± 0.1°C and the heart rate of each embryo was measured. Heart rates were first detectable in 13 eggs at day 6 of incubation. At day 7, an average heart rate of 170 ± 20 beats/min was detected in all 29 fertile eggs, which is comparable to reported values. Ten additional SPF chicken eggs were evaluated at day 13 of incubation to test the effects of ambient temperature changes on embryonic heart rate. Embryonic heart rates dropped from 262 to 106 beats/min in eggs kept at room temperature (25°C) for 90 minutes and to <60 beats/...

Síncope convulsivo: características y reproducibilidad mediante la prueba de la cama basculante

To establish the main clinical characteristics of convulsive syncope and the usefulness of the tilt test in its diagnosis. A total of 317 patients (aged 5-18 years old) under clinical suspicion of neurocardiogenic syncope underwent a multiparametric tilt test. Our tilt test protocol includes continuous noninvasive measurement of heart rate, blood pressure, and arterial oxygen saturation, as well as continuous noninvasive measurement of cerebral oxygen saturation by near-infrared spectrophotometry. In selected patients, simultaneous electroencephalogram (EEG) was performed. The tilt test was positive in 216 patients (68.1 %). Of these, 25 (11.6 %) showed seizures during the test (convulsive syncope). Convulsions were asymmetric-tonic in 15 patients (60 %), generalized tonic in 5 (20 %), and tonic-clonic in 5 (20 %). In all patients, convulsive episodes lasted less than 30 seconds and spontaneously ceased upon placing the patient in a horizontal or Trendelenburg position. When simultaneous EEG was performed, diffuse brain wave slowing was observed, without paroxysmal activity. Convulsive syncope is not an uncommon event in children and is easily elicited by means of the tilt test. Pediatricians should be aware of this finding in order to avoid the frequently established unidirectional association between seizures and epileptic disorders. Consequently, the tilt test should be considered an essential tool in the differential diagnosis between convulsive syncope and epilepsy.

Real-time non-invasive measurement of heart rate inworking dogs: a technique with potential applications in the objective assessment of welfare problems

The Polar Sport Tester (Polar Electro OY) is a telemetric heart rate monitor designed for use in humans. Its usefulness as a monitor during training of guide dogs is assessed in this paper. Heart rates from six representative dogs at a similar stage of early training were recorded at 5-s intervals during a 15-20 min work session. The dogs were F1 Labrador Retriever x Golden Retrievers. They were chosen if their behaviour could be clearly categorized by their experienced trainers as either 'calm/non-stress prone' (Type A) or 'excitable/stress prone' (Type B) during work. Verbal recordings were made of environmental cues and behavioural responses in each dog. Variability in heart rate was significantly related to a subject's described temperament.

Artificial eggs: Measuring heart rate and effects of disturbance in nesting penguins

A technique for the noninvasive measurement of heart rate in incubating penguins is described and evaluated. The technique uses an artificial egg fitted with an infrared sensor. Placing the egg in the nest causes minimal disturbance to the resident penguin; this penguin is then paint-marked so that subsequent measurements may be taken from the unmarked, naive partner once it assumes incubation. Heart rate changes are useful indicators of nesting penguins' reactions to events in their environment because often their behaviour does not appear to vary in response to a threat until the point at which they flee, exposing eggs and chicks to predators. The eggs can be readily transferred from one nest to another. They have been successfully deployed on both African ( Spheniscus demersus) and Gentoo Penguins ( Pygoscelis papua). The design should be readily adaptable for use with other seabirds and passerines.

Circulatory adaptation to orthostatic stress in healthy 10-14-year-old children investigated in a general practice.

1. The magnitude and time course of circulatory adaptation to active standing were investigated in healthy premenarchic girls and boys (n = 24; 10-14 years old) by non-invasive measurement of heart rate and continuous finger blood pressure (Finapres). 2. Four subjects (two girls, two boys) showed presyncopal symptoms after 4-9 min of free standing. 3. In the 20 non-fainting subjects, changes in blood pressure and heart rate upon standing did not differ between girls (n = 10) and boys (n = 10). In the initial phase of standing (first 30 s) systolic and diastolic blood pressures dropped by 22 +/- 14 (mean +/- SD) and 16 +/- 7 mmHg, respectively, at 8 +/- 2 s. Blood pressure subsequently recovered and showed an overshoot in all subjects. The transient drop in blood pressure was accompanied by an increase in heart rate of 40 +/- 7 beats/min. These characteristic transient changes were not observed with passive head-up tilt. During the early steady-state phase (2 min), systolic blood pressure was similar to the supine value and diastolic blood pressure rose by 11 +/- 5 mmHg. Heart rate increased by 25 +/- 11 beats/min. In six of the subjects (three girls, three boys) the increase in heart rate exceeded 30 beats/min (postural tachycardia). Little further changes were observed during prolonged (10 min) standing.(ABSTRACT TRUNCATED AT 250 WORDS)