Heartbeat Parameters Research Articles

Laser-Induced Graphene for Heartbeat Monitoring with HeartPy Analysis.

The HeartPy Python toolkit for analysis of noisy signals from heart rate measurements is an excellent tool to use in conjunction with novel wearable sensors. Nevertheless, most of the work to date has focused on applying the toolkit to data measured with commercially available sensors. We demonstrate the application of the HeartPy functions to data obtained with a novel graphene-based heartbeat sensor. We produce the sensor by laser-inducing graphene on a flexible polyimide substrate. Both graphene on the polyimide substrate and graphene transferred onto a PDMS substrate show piezoresistive behavior that can be utilized to measure human heartbeat by registering median cubital vein motion during blood pumping. We process electrical resistance data from the graphene sensor using HeartPy and demonstrate extraction of several heartbeat parameters, in agreement with measurements taken with independent reference sensors. We compare the quality of the heartbeat signal from graphene on different substrates, demonstrating that in all cases the device yields results consistent with reference sensors. Our work is a first demonstration of successful application of HeartPy to analysis of data from a sensor in development.

Drosophila Heart as a Model for Cardiac Development and Diseases.

The Drosophila heart, also referred to as the dorsal vessel, pumps the insect blood, the hemolymph. The bilateral heart primordia develop from the most dorsally located mesodermal cells, migrate coordinately, and fuse to form the cardiac tube. Though much simpler, the fruit fly heart displays several developmental and functional similarities to the vertebrate heart and, as we discuss here, represents an attractive model system for dissecting mechanisms of cardiac aging and heart failure and identifying genes causing congenital heart diseases. Fast imaging technologies allow for the characterization of heartbeat parameters in the adult fly and there is growing evidence that cardiac dysfunction in human diseases could be reproduced and analyzed in Drosophila, as discussed here for heart defects associated with the myotonic dystrophy type 1. Overall, the power of genetics and unsuspected conservation of genes and pathways puts Drosophila at the heart of fundamental and applied cardiac research.

Open access tool and microfluidic devices for phenotypic quantification of heart function of intact fruit fly and zebrafish larvae

In this paper, the heartbeat parameters of small model organisms, i.e. Drosophila melanogaster (fruit fly) and Danio rerio (zebrafish), were quantified in-vivo in intact larvae using microfluidics and a novel MATLAB-based software. Among different developmental stages of flies and zebrafish, the larval stage is privileged due to biological maturity, optical accessibility, and the myogenic nature of the heart. Conventional methods for parametric quantification of heart activities are complex and mostly done on dissected, irreversibly immobilized, or anesthetized larvae. Microfluidics has helped with reversible immobilization without the need for anesthesia, but heart monitoring is still done manually due to challenges associated with the movement of floating organs and cardiac interruptions. In our MATLAB software applied to videos recorded in microfluidic-based whole-organism assays, we have used image segmentation to automatically detect the heart and extract the heartbeat signal based on pixel intensity variations of the most contractile region of the heart tube. The smoothness priors approach (SPA) was applied to remove the undesired low-frequency noises caused by environmental light changes or heart movement. Heart rate and arrhythmicity were automatically measured from the detrended heartbeat signal while other parameters including end-diastolic and end-systolic diameters, shortening distance, shortening time, fractional shortening, and shortening velocity were quantified for the first time in intact larvae, using M-mode images under bright field microscopy. The software was able to detect more than 94% of the heartbeats and the cardiac arrests in intact Drosophila larvae. Our user-friendly software enables in-vivo quantification of D. melanogaster and D. rerio larval heart functions in microfluidic devices, with the potential to be applied to other biological models and used for automatic screening of drugs and alleles that affect their heart.

Biometric signal processing at radar remote diagnostics of cardio-respiratory human activity

Radar units which are able to diagnose the state of living organisms, can find the widest application. The estimation method based on respiration and heartbeat parameters of the person has been suggested. The mathematical modeling for algorithm optimization of obtaining the necessary signals and determination of their spectral characteristics has been carried out.

Effect of supplementation of pelleted hazel (Corylus avellana) leaves on blood antioxidant activity, cellular immune response, and heart beat parameters in sheep1.

Hazel leaves (Corylus avellana) fed to sheep resulted in decreased methane emissions without negatively affecting feed intake and were found to have antioxidant properties in vitro. The objective of this study was to evaluate effects of hazel leaves, rich in tannins, on blood antioxidant activity, cellular immune response, and heart beat parameters in sheep. Four experimental pellets were produced by mixing alfalfa and hazel leaves in different proportions, including alfalfa alone as a control, 30% and 60% of hazel leaves, the latter also with 3.8% polyethylene glycol (PEG). Six adult, nonpregnant, nonlactating female sheep (71 ± 5.7 kg of body weight) were allocated to 4 treatments in a 6 × 4 crossover design with four 18-d periods. The diet consisted of experimental pellets and ryegrass-dominated hay (ratio 80% to 20% in dry matter), resulting in hazel leaf proportions of approximately 0%, 25%, and 50% in the total diet. Blood samples were collected at the end of each period to determine plasma total phenol concentration and markers of oxidative status as well as peripheral blood mononuclear cells (PBMC) activation and proliferation response in vitro. Heart rate (HR) and HR variability parameters were measured for 2 consecutive days in each period, during different activities (i.e., eating pellets or hay, or lying). Treatments were compared with multiple comparisons and contrast analysis was used to test for linear and quadratic relations. Compared with control, feeding a high dosage of hazel leaves enhanced (P = 0.006) the plasma total antioxidant capacity, which linearly (P = 0.016) increased with increasing level of hazel leaves in the diet. The total phenol concentration and activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione reductase in the plasma were not different (P ≥ 0.23) among the treatments; however, the latter slightly increased linearly (P = 0.047) with increasing hazel leaves proportion. No differences were observed in the activation and proliferation of PBMC among treatments. The HR decreased linearly (P ≤ 0.009) during pellet eating and lying and the root mean square of successive differences of interbeat intervals (RMSSD) increased linearly (P = 0.037) when lying with increasing level of hazel leaves in the diet. In conclusion, our findings indicate that hazel leaves are a promising supplement to improve oxidative status with no effect on cellular immune response and cardiac stress level of sheep.

Effect of Benson's relaxation technique on the anxiety of patients undergoing coronary angiography: A randomized control trial

Background and Purpose: Anxiety is a common problem associated with invasive medical procedures, especially in patients undergoing coronary angiography. As an intensifier at cardiovascular reactions, anxiety poses significant risk to the health of patients undergoing angiography. Researchers believe that use of Benson's relaxation technique could reduce anxiety in different patients. This study aimed to evaluate the effect of Benson's relaxation technique on the anxiety of patients undergoing coronary angiography. Methods: This randomized clinical trial was conducted on 70 patients who were candidates for coronary angiography in Mazandaran Heart Center in Sari, Iran in 2014. Patients were selected via randomized sampling and divided into two groups of intervention (n=35) and control (n=35). Data collection tools included demographic questionnaire, Spielberger's State-Trait Anxiety Inventory (STAI), and hemodynamic variables recording sheet. Data analysis was performed in SPSS V. 16 using Chi-square, dependent and paired T-test, and Mann-Whitney U test. Results: Both study groups were homogenous in terms of age, gender, marital status, education level, disease history, and health insurance status. Use of Benson's relaxation technique significantly decreased anxiety in the intervention group (P=0.0001). However, no significant difference was observed in the systolic blood pressure, respiratory rate and heartbeat parameters between the study groups (P=0.0001). Conclusion: According to the results of this study, use of Benson's relaxation technique before coronary angiography reduced the level of anxiety in the patients. Therefore, this complementary approach could be used as an effective healthcare measure without any side effects to provide mental support for patients before invasive procedures, such as angiography.

Effects of sounds of different quality on the behaviour and heart beat parameters of goats

In alpine regions, bells are used to relocate free-ranging grazers like cows and goats. Considering that goats have a well-developed hearing capacity, sounds (e.g. a chime of a bell) may act as stressors depending on their characteristics. The aim of this study was to test whether a non-uniform sound (chime of a bell) varying in amplitude and frequency and a uniform sound (sinusoidal tone) with continuously increasing amplitude and constant frequency lead to stress responses in terms of behaviour and heartbeat. Twenty-nine goats were tested individually in a test arena in two sessions, each lasting five consecutive days with one trial per day. A day before the first trial, reference values were collected without playback. During the following five trials, playbacks were conducted. Differences in behaviour and heartbeat parameters between test and reference values were analysed by using generalised linear mixed-effects models. During the first trial, the relative feeding duration was decreased and the relative alertness duration was increased during both stimuli, but more when goats were exposed to the non-uniform than the uniform sound. For both stimuli, the relative feeding duration increased (trial×stimulus: P=0.05) and the relative alertness duration decreased (trial×stimulus: P=0.004) from the first to the fifth trial but returned to the levels of the reference values sooner when goats were exposed to the uniform than the non-uniform sound. Cardiac activity was not affected by the stimuli. Altogether, the chime of a bell led to higher behavioural arousal than the uniform sinusoidal tone, indicating a potential of the chime to being more aversive to goats than a uniform sound. With repeated exposure to the stimuli, goats habituated to both stimuli, but habituation was faster to the sinusoidal sound than to the chime of a bell. Free-ranging goats in alpine regions usually are equipped with bells 24h a day during the summer season. Thus, the question arises whether the long-term exposure to the chime of a bell might have negative effects on animal welfare.

Automatic zebrafish heartbeat detection and analysis for zebrafish embryos.

A fully automatic detection and analysis method of heartbeats in videos of nonfixed and nonanesthetized zebrafish embryos is presented. This method reduces the manual workload and time needed for preparation and imaging of the zebrafish embryos, as well as for evaluating heartbeat parameters such as frequency, beat-to-beat intervals, and arrhythmicity. The method is validated by a comparison of the results from automatic and manual detection of the heart rates of wild-type zebrafish embryos 36-120 h postfertilization and of embryonic hearts with bradycardia and pauses in the cardiac contraction.

A New Method for Detection and Quantification of Heartbeat Parameters in Drosophila, Zebrafish, and Embryonic Mouse Hearts

The genetic basis of heart development is remarkably conserved from Drosophila to mammals, and insights from flies have greatly informed our understanding of vertebrate heart development. Recent evidence suggests that many aspects of heart function are also conserved and the genes involved in heart development also play roles in adult heart function. We have developed a Drosophila heart preparation and movement analysis algorithm that allows quantification of functional parameters. Our methodology combines high-speed optical recording of beating hearts with a robust, semi-automated analysis to accurately detect and quantify, on a beat-to-beat basis, not only heart rate but also diastolic and systolic intervals, systolic and diastolic diameters, percent fractional shortening, contraction wave velocity, and cardiac arrhythmicity. Here, we present a detailed analysis of hearts from adult Drosophila, 2-3-day-old zebrafish larva, and 8-day-old mouse embryos, indicating that our methodology is potentially applicable to an array of biological models. We detect progressive age-related changes in fly hearts as well as subtle but distinct cardiac deficits in Tbx5 heterozygote mutant zebrafish. Our methodology for quantifying cardiac function in these genetically tractable model systems should provide valuable insights into the genetics of heart function.

Estimation of the involvement of subconsciousness in heartbeat perception in healthy volunteers

The results of analysis of heartbeat parameters and characteristics of its self-monitoring by 25 healthy volunteers have been used as the basis for original estimation of the involvement of subconsciousness in heartbeat perception. The first objective index for such estimation is proposed. It is calculated as the individual fragmentation coefficient of heartbeat perception. The discreteness of heartbeat perception is related to changes in the degree (weight) of involvement of subconsciousness in the perception of cardiac signals. A conclusion is drawn on the relationship between the efficiency of perception of one’s own heartbeat and the degree of involvement of subconsciousness in this process. The practical implication of the study is the possibility of using a similar approach to estimating the weight of unconscious processes in perception of stimuli of different types, including those used in psychodiagnostic studies.