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Sample records for heart rate coordination

  1. Influence of paced maternal breathing on fetal–maternal heart rate coordination

    PubMed Central

    Van Leeuwen, P.; Geue, D.; Thiel, M.; Cysarz, D.; Lange, S.; Romano, M. C.; Wessel, N.; Kurths, J.; Grönemeyer, D. H.

    2009-01-01

    Pregnant mothers often report a special awareness of and bonding with their unborn child. Little is known about this relationship although it may offer potential for the assessment of the fetal condition. Recently we found evidence of short epochs of fetal–maternal heart rate synchronization under uncontrolled conditions with spontaneous maternal breathing. Here, we examine whether the occurrence of such epochs can be influenced by maternal respiratory arrhythmia induced by paced breathing at several different rates (10, 12, 15, and 20 cycles per minute). To test for such weak and nonstationary synchronizations among the fetal–maternal subsystems, we apply a multivariate synchronization analysis technique and test statistics based on twin surrogates. We find a clear increase in synchronization epochs mostly at high maternal respiratory rates in the original but not in the surrogate data. On the other hand, fewer epochs are found at low respiratory rates both in original and surrogate data. The results suggest that the fetal cardiac system seems to possess the capability to adjust its rate of activation in response to external—i.e., maternal—stimulation. Hence, the pregnant mothers' special awareness to the unborn child may also be reflected by fetal–maternal interaction of cardiac activity. Our approach opens up the chance to examine this interaction between independent but closely linked physiological systems. PMID:19597150

  2. Heart Rate Monitors

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Under a NASA grant, Dr. Robert M. Davis and Dr. William M. Portnoy came up with a new type of electrocardiographic electrode that would enable long term use on astronauts. Their invention was an insulated capacitive electrode constructed of a thin dielectric film. NASA subsequently licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber, who founded Heart Rate, Inc., to further develop and manufacture personal heart monitors and to produce exercise machines using the technology for the physical fitness, medical and home markets. Same technology is on both the Home and Institutional Model VersaClimbers. On the Home Model an infrared heart beat transmitter is worn under exercise clothing. Transmitted heart rate is used to control the work intensity on the VersaClimber using the heart rate as the speedometer of the exercise. This offers advantages to a full range of users from the cardiac rehab patient to the high level physical conditioning of elite athletes. The company manufactures and markets five models of the 1*2*3 HEART RATE monitors that are used wherever people exercise to accurately monitor their heart rate. Company is developing a talking heart rate monitor that works with portable headset radios. A version of the heart beat transmitter will be available to the manufacturers of other aerobic exercise machines.

  3. Target Heart Rate Calculator

    MedlinePlus

    ... workout Enter your age to find a target heart rate during exercise. You'll get the most out of your activities by staying within this range of heartbeats/minute. Please enter your age in years Calculate Your target heart rate is beats per minute. How to Check Your ...

  4. The Clinical Coordinator's Role in Heart Transplantation

    PubMed Central

    Powers, Penny L.

    1987-01-01

    The role of the clinical coordinator in a heart transplant program is one of the most comprehensive in nursing, because the coordinator follows the patient through the entire evaluation procedure, through preoperative and postoperative care, and indeed throughout the remainder of his life. (Texas Heart Institute Journal 1987; 14:243-246) PMID:15227305

  5. Heart rate turbulence.

    PubMed

    Cygankiewicz, Iwona

    2013-01-01

    Heart rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of heart rate in response to premature ventricular beats. Heart rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of heart rate following premature beat and turbulence slope (TS) describing subsequent deceleration of heart rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death.

  6. Heart Rate Monitor

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the mid 70's, NASA saw a need for a long term electrocardiographic electrode suitable for use on astronauts. Heart Rate Inc.'s insulated capacitive electrode is constructed of thin dielectric film applied to stainless steel surface, originally developed under a grant by Texas Technical University. HRI, Inc. was awarded NASA license and continued development of heart rate monitor for use on exercise machines for physical fitness and medical markets.

  7. Noninvasive Heart Rate Monitor

    DTIC Science & Technology

    1983-07-31

    plethysmography can be applied to various parts of the body such as finger, toe, ear, forehead, neck, wrist and so on. The choice of location is predicated upon...frequency, hydrostatic, cardiac vibration wave is also explored. 3 2.0 METHODOLOGY The basic methodology and underlying principle of the heart rate monitor...regarding heart rate can be extracted in a number of ways. In the present application, the Doppler effect will be utilized. The principle of

  8. Noninvasive Heart Rate Monitor

    DTIC Science & Technology

    1983-08-01

    NUMOEN2. GVT ACCESSION NO.2 ReCIPICUTS CATALOG NUMOeaR 14 -A674P ;-FR 4. TITLE (end S.dU. L TYPE OF RgPORT & PCFmOO covgeno Noninvasive Heart Rate monitor...WHNWIM AMINOw3 I& SUPPLEMENTARYV NOTES A9-W A IS. KCY WORDS (Canam. an ,. d" it4 II wooe.p ad IiEEr 6F AAm Heart Raet Monitor; Doppler Detector...of using a handheld, battery operated, cv microwave radar, operating at 2.45 GHs, for use as a heart rate monitor under chemically contaminated

  9. All about Heart Rate (Pulse)

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More All About Heart Rate (Pulse) Updated:Aug 22,2017 ... Blood Pressure is Diagnosed BP vs. Heart Rate All About Heart Rate (Pulse) Low Blood Pressure Resistant ...

  10. All about Heart Rate (Pulse)

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More All About Heart Rate (Pulse) Updated:Apr 19,2016 ... are the Symptoms of High Blood Pressure? 7 All About Heart Rate (Pulse) 8 Tachycardia | Fast Heart ...

  11. Modelling Heart Rate Kinetics

    PubMed Central

    Zakynthinaki, Maria S.

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual’s cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  12. Modelling heart rate kinetics.

    PubMed

    Zakynthinaki, Maria S

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual's cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women).

  13. Mechanical signaling coordinates the embryonic heart

    NASA Astrophysics Data System (ADS)

    Chiou, Kevin; Rocks, Jason; Prosser, Benjamin; Discher, Dennis; Liu, Andrea

    The heart is an active material which relies on robust signaling mechanisms between cells in order to produce well-timed, coordinated beats. Heart tissue is composed primarily of active heart muscle cells (cardiomyocytes) embedded in a passive extracellular matrix. During a heartbeat, cardiomyocyte contractions are coordinated across the heart to form a wavefront that propagates through the tissue to pump blood. In the adult heart, this contractile wave is coordinated via intercellular electrical signaling.Here we present theoretical and experimental evidence for mechanical coordination of embryonic heartbeats. We model cardiomyocytes as mechanically excitable Eshelby inclusions embedded in an overdamped elastic-fluid biphasic medium. For physiological parameters, this model replicates recent experimental measurements of the contractile wavefront which are not captured by electrical signaling models. We additionally challenge our model by pharmacologically blocking gap junctions, inhibiting electrical signaling between myocytes. We find that while adult hearts stop beating almost immediately after gap junctions are blocked, embryonic hearts continue beating even at significantly higher concentrations, providing strong support for a mechanical signaling mechanism.

  14. Heart rate monitoring mobile applications

    PubMed Central

    2016-01-01

    Total number of times a heart beats in a minute is known as the heart rate. Traditionally, heart rate was measured using clunky gadgets but these days it can be measured with a smartphone’s camera. This can help you measure your heart rate anywhere and at anytime, especially during workouts so you can adjust your workout intensity to achieve maximum health benefits. With simple and easy to use mobile app, ‘Unique Heart Rate Monitor’, you can also maintain your heart rate history for personal reflection and sharing with a provider. PMID:28293594

  15. Reduced Heart Rate Volatility

    PubMed Central

    Grogan, Eric L.; Morris, John A.; Norris, Patrick R.; France, Daniel J.; Ozdas, Asli; Stiles, Renée A.; Harris, Paul A.; Dawant, Benoit M.; Speroff, Theodore

    2004-01-01

    Objective: To determine if using dense data capture to measure heart rate volatility (standard deviation) measured in 5-minute intervals predicts death. Background: Fundamental approaches to assessing vital signs in the critically ill have changed little since the early 1900s. Our prior work in this area has demonstrated the utility of densely sampled data and, in particular, heart rate volatility over the entire patient stay, for predicting death and prolonged ventilation. Methods: Approximately 120 million heart rate data points were prospectively collected and archived from 1316 trauma ICU patients over 30 months. Data were sampled every 1 to 4 seconds, stored in a relational database, linked to outcome data, and de-identified. HR standard deviation was continuously computed over 5-minute intervals (CVRD, cardiac volatility–related dysfunction). Logistic regression models incorporating age and injury severity score were developed on a test set of patients (N = 923), and prospectively analyzed in a distinct validation set (N = 393) for the first 24 hours of ICU data. Results: Distribution of CVRD varied by survival in the test set. Prospective evaluation of the model in the validation set gave an area in the receiver operating curve of 0.81 with a sensitivity and specificity of 70.1 and 80.0, respectively. CVRD predict death as early as 24 hours in the validation set. Conclusions: CVRD identifies a subgroup of patients with a high probability of dying. Death is predicted within first 24 hours of stay. We hypothesize CVRD is a surrogate for autonomic nervous system dysfunction. PMID:15319726

  16. Tachycardia | Fast Heart Rate

    MedlinePlus

    ... heart disease and stroke. Start exploring today ! Printable Arrhythmia Information Sheets What is Arrhythmia? What is Atrial ... Card See all Answers by Heart patient sheets Arrhythmia • Home • About Arrhythmia Introduction Atrial Fibrillation Bradycardia Conduction ...

  17. Target Heart Rates

    MedlinePlus

    ... a Healthy Heart Healthy Kids Our Kids Programs Childhood Obesity What is childhood obesity? Overweight in Children BMI in Children Is Childhood Obesity an Issue in Your Home? Addressing your Child's ...

  18. Heart rates during competitive orienteering.

    PubMed

    Bird, S R; Bailey, R; Lewis, J

    1993-03-01

    This study investigated the heart rate profiles of 16 experienced, competitive orienteers (aged 15-62 years) during three competitive events. Each competitor was assessed over three different types of course which were classified as: fast run (FR), slow run (SR) and highly physical (HP). The results showed that all subjects recorded heart rates that were between 140 and 180 beats min-1 for the majority of each event (irrespective of age or course type). The heart rate data indicated that the activity was largely aerobic but varied in intensity, with phases of strenuous anaerobic work. The type of course was shown significantly (analysis of variance; P < 0.001) to affect the mean heart rate attained by each orienteer (FR = 160, HP = 158, SR = 150 beats min-1), with courses that required more technical skill and hence slower running producing lower mean heart rates; although the general physical demands were similar for all courses. The older orienteers (> 45 years) recorded heart rate profiles that were similar to those of the young orienteers with no correlation being found between age and mean heart rate while exercising.

  19. Heart rates during competitive orienteering.

    PubMed Central

    Bird, S R; Bailey, R; Lewis, J

    1993-01-01

    This study investigated the heart rate profiles of 16 experienced, competitive orienteers (aged 15-62 years) during three competitive events. Each competitor was assessed over three different types of course which were classified as: fast run (FR), slow run (SR) and highly physical (HP). The results showed that all subjects recorded heart rates that were between 140 and 180 beats min-1 for the majority of each event (irrespective of age or course type). The heart rate data indicated that the activity was largely aerobic but varied in intensity, with phases of strenuous anaerobic work. The type of course was shown significantly (analysis of variance; P < 0.001) to affect the mean heart rate attained by each orienteer (FR = 160, HP = 158, SR = 150 beats min-1), with courses that required more technical skill and hence slower running producing lower mean heart rates; although the general physical demands were similar for all courses. The older orienteers (> 45 years) recorded heart rate profiles that were similar to those of the young orienteers with no correlation being found between age and mean heart rate while exercising. PMID:8457815

  20. Blood Pressure vs. Heart Rate

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Blood Pressure vs. Heart Rate (Pulse) Updated:Jan 18,2017 ... content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

  1. Dimensional analysis of heart rate variability in heart transplant recipients

    SciTech Connect

    Zbilut, J.P.; Mayer-Kress, G.; Geist, K.

    1987-01-01

    We discuss periodicities in the heart rate in normal and transplanted hearts. We then consider the possibility of dimensional analysis of these periodicities in transplanted hearts and problems associated with the record.

  2. Heart rate variability and heart rate recovery as prognostic factors.

    PubMed

    Grad, Cosmin

    2015-01-01

    Heart rate (HR) can appear static and regular at rest, during exercise or recovery after exercise. However, HR is constantly adjusted due to factors such as breathing, blood pressure control, thermoregulation and the renin-angiotensin system, leading to a more dynamic response that can be quantified using HRV (heart rate variability). HRV is defined as the deviation in time between successive normal heart beat and is a noninvasive method to measure the total variation in a number of HR interval. HRV can serve as measure of autonomic activity of sino-atrial node. The aim of the study was to determine the influence of certain clinical and paraclinical parameters on heart rate recovery after exercise in patients with ischemic heart disease and the relation with HRV using 24 h Holter monitoring. The study included 46 patients who were submitted to cardiovascular exercise stress test and also to 24 h Holter EKG monitoring. Subjects had a mean age of 56.2±11.2 years, with a minimum of 25 and a maximum of 79 years. The study included 22 (47.8%) men and 24 (52.2%) women. Statistical analysis was performed using MedCalc software version 14.8.1. Multivariate analysis consisted of the construction of several multiple linear regression models. A p value of 0.05 was considered statistically significant. The HRV values (time domain) were all lower in the IHD compared with the group without coronary heart disease, even if the difference is not statistically significant. Also rest and maximal HR values were similar but during the test varies in the sense that those with IHD had higher values of rest and maximal HR and lower HRR, but not statistically significant. HRV is a very easy and safe method if there is an available device and it is used for evaluation of the autonomic nervous system in many cardiovascular diseases, but also in other pathologies. In uncomplicated ischemic heart disease HRV is depressed, but not significant. HRR, which is also considered an indicator of the

  3. Multifractality and heart rate variability

    NASA Astrophysics Data System (ADS)

    Sassi, Roberto; Signorini, Maria Gabriella; Cerutti, Sergio

    2009-06-01

    In this paper, we participate to the discussion set forth by the editor of Chaos for the controversy, "Is the normal heart rate chaotic?" Our objective was to debate the question, "Is there some more appropriate term to characterize the heart rate variability (HRV) fluctuations?" We focused on the ≈24 h RR series prepared for this topic and tried to verify with two different techniques, generalized structure functions and wavelet transform modulus maxima, if they might be described as being multifractal. For normal and congestive heart failure subjects, the hq exponents showed to be decreasing for increasing q with both methods, as it should be for multifractal signals. We then built 40 surrogate series to further verify such hypothesis. For most of the series (≈75%-80% of cases) multifractality stood the test of the surrogate data employed. On the other hand, series coming from patients in atrial fibrillation showed a small, if any, degree of multifractality. The population analyzed is too small for definite conclusions, but the study supports the use of multifractal series to model HRV. Also it suggests that the regulatory action of autonomous nervous system might play a role in the observed multifractality.

  4. Cilia and coordination of signaling networks during heart development

    PubMed Central

    Koefoed, Karen; Veland, Iben Rønn; Pedersen, Lotte Bang; Larsen, Lars Allan; Christensen, Søren Tvorup

    2014-01-01

    Primary cilia are unique sensory organelles that coordinate a wide variety of different signaling pathways to control cellular processes during development and in tissue homeostasis. Defects in function or assembly of these antenna-like structures are therefore associated with a broad range of developmental disorders and diseases called ciliopathies. Recent studies have indicated a major role of different populations of cilia, including nodal and cardiac primary cilia, in coordinating heart development, and defects in these cilia are associated with congenital heart disease. Here, we present an overview of the role of nodal and cardiac primary cilia in heart development. PMID:24345806

  5. Heart Rate and Behavior of Twins.

    ERIC Educational Resources Information Center

    Boomsma, Dorret I.; Plomin, Robert

    1986-01-01

    Genetic and environmental influences on heart rate were studied in samples of twin pairs in middle childhood. Heart rate was measured in resting situation and under two task conditions. Heart rate was related to parental ratings of shyness, emotionality, and selective attention measure. Multivariate analysis suggested that covariance between heart…

  6. Wearable sensor for heart rate detection

    NASA Astrophysics Data System (ADS)

    Shi, Cong; Liu, Xiaohua; Kong, Lingqin; Wu, Jizhe; Liu, Ming; Dong, Liquan; Hui, Mei; Zhao, Yuejin

    2015-08-01

    In recent years heart and blood vessel diseases kill more people than everything else combined. The daily test of heart rate for the prevention and treatment of the heart head blood-vessel disease has the vital significance. In order to adapt the transformation of medical model and solve the low accuracy problem of the traditional method of heart rate measuring, we present a new method to monitor heart rate in this paper. The heart rate detection is designed for daily heart rate detection .The heart rate signal is collected by the heart rate sensor. The signal through signal processing circuits converts into sine wave and square wave in turn. And then the signal is transmitted to the computer by data collection card. Finally, we use LABVIEW and MATLAB to show the heart rate wave and calculate the heart rate. By doing contrast experiment with medical heart rate product, experimental results show that the system can realize rapidly and accurately measure the heart rate value. A measurement can be completed within 10 seconds and the error is less than 3beat/min. And the result shows that the method in this paper has a strong anti-interference ability. It can effectively suppress the movement interference. Beyond that the result is insensitive to light.

  7. [Resting heart rate and cardiovascular disease].

    PubMed

    Brito Díaz, Buenaventura; Alemán Sánchez, José Juan; Cabrera de León, Antonio

    2014-07-07

    Heart rate reflects autonomic nervous system activity. Numerous studies have demonstrated that an increased heart rate at rest is associated with cardiovascular morbidity and mortality as an independent risk factor. It has been shown a link between cardiac autonomic balance and inflammation. Thus, an elevated heart rate produces a micro-inflammatory response and is involved in the pathogenesis of endothelial dysfunction. In turn, decrease in heart rate produces benefits in congestive heart failure, myocardial infarction, atrial fibrillation, obesity, hyperinsulinemia, insulin resistance, and atherosclerosis. Alteration of other heart rate-related parameters, such as their variability and recovery after exercise, is associated with risk of cardiovascular events. Drugs reducing the heart rate (beta-blockers, calcium antagonists and inhibitors of If channels) have the potential to reduce cardiovascular events. Although not recommended in healthy subjects, interventions for reducing heart rate constitute a reasonable therapeutic goal in certain pathologies.

  8. Rhesus monkey heart rate during exercise

    NASA Technical Reports Server (NTRS)

    Delorge, J.; Thach, J. S., Jr.

    1972-01-01

    Various schedules of reinforcement and their relation to heart rates of rhesus monkeys during exercise are described. All the reinforcement schedules produced 100 per cent or higher increments in the heart rates of the monkeys during exercise. Resting heart rates were generally much lower than those previously reported, which was attributed to the lack of physical restraint of the monkeys during recording.

  9. Heart rate in professional musicians

    PubMed Central

    Iñesta, Claudia; Terrados, Nicolás; García, Daniel; Pérez, José A

    2008-01-01

    Background Very few studies have analysed heart rate (HR) with regard to music playing, and the scarce evidence available is controversial. The purpose of this study was to analyse the HR response of professional musicians during their real-work activity. Methods Sixty-two voluntary professional musicians (20 women, 42 men), whose ages ranged between 15 and 71 years old, underwent the test while playing their instruments in real life scenarios, i.e. rehearsals, practice and public concerts. The musicians carried Sport Tester PE4000 (Polar®, Finland) pulsometers to record their HR. In order to compare data from differently aged subjects we calculated their Maximum Theoretical Heart Rate (MTHR). Later on we found out the MTHR percentages (%MTHR) corresponding to the registered HR of each subject in different situations. The value of the MTHR for every musician was obtained by means of the 220 – age (in years) formula. Results Throughout the HR recordings, we have observed that musicians present a heightened HR while playing (in soloists, mean and maximum HR were 72% and 85%MTHR, respectively). Cardiac demand is significantly higher in concerts than in rehearsals while performing the same musical piece. The HR curves corresponding to the same musician playing in repeated concerts (with the same programme) were similar. Conclusion The cardiac demand of a professional instrument player is higher than previously described, much greater than what would be expected from a supposedly sedentary activity. PMID:18655716

  10. HEART RATE CONDITIONING IN THE RAT,

    DTIC Science & Technology

    PULSE RATE, CONDITIONED RESPONSE), (*CONDITIONED RESPONSE, PULSE RATE), HEART , FEAR, ANXIETY, EMOTIONS, STIMULATION(PHYSIOLOGY), PSYCHOPHYSIOLOGY, AUTONOMIC NERVOUS SYSTEM, ANALYSIS OF VARIANCE, RATS

  11. Rhesus Monkey Heart Rate during Exercise,

    DTIC Science & Technology

    Three rhesus monkeys were implanted with ECG telemeters and performed a calisthenic exercise requiring complete arm extension above their heads and...reinforcement schedules. Heart rate samples were obtained both during sleep and high rates of activity. Two animals provided exercise data and one animal...provided data without the exercise task. Highest heart rates were seen in the two exercise animals. No differences in maximum heart rates were related to

  12. Maternal heart rate changes during labour.

    PubMed

    Söhnchen, N; Melzer, K; Tejada, B Martinez de; Jastrow-Meyer, N; Othenin-Girard, V; Irion, O; Boulvain, M; Kayser, B

    2011-10-01

    Labour and delivery represent a considerable effort for pregnant women. Lack of aerobic fitness may limit pushing efforts during childbirth and represents increased cardiovascular strain and risk. Increasing prevalence of sedentary behaviour and lack of aerobic fitness may reduce heart rate reserve during labour. We quantified maternal heart rate reserve (maximum heart rate minus resting heart rate) of 30 healthy pregnant women during labour and delivery and related it to habitual daily physical activity levels quantified during the third pregnancy trimester by the Pregnancy Physical Activity Questionnaire. Heart rates during labour reached values similar to those observed during moderate to heavy physical exercise. During active pushing one out of five women reached heart rates more than 90% of their heart rate reserve (188 ± 7 beats per min). Half of the women reached more than 70% of heart rate reserve (172 ± 14 beats per min). Physically inactive women used more of their heart rate reserve as physically more active women (87 ± 20% vs. 65 ± 12%, upper and lower tertile respectively, p<0.05). Use of heart rate reserve for the effort of labour is increased in physically inactive women and may potentially limit the intensity and duration of pushing efforts. Such higher cardiovascular strain in physically less active women may represent increased cardiovascular risk during labour. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  13. Heart rate control during treadmill exercise.

    PubMed

    Su, S W; Wang, L; Celler, B G; Savkin, A

    2005-01-01

    A computer-controlled treadmill and related data collection and processing systems have been developed for the control of heart rate during treadmill exercise. Minimizing deviations of heart rate from a preset profile is achieved by controlling the speed and/or the gradient of the treadmill. A simple and practical heart rate measurement algorithm has been developed to robustly measure the variations of heart rate. Both conventional Proportional-Integral-Derivative (PID) control and fuzzy Proportional-Integral (PI) control approaches have been employed for the controller design. The fuzzy Proportional-Integral algorithm achieved better heart rate tracking performance. Finally, a heart rate based exercising protocol was successfully implemented on the newly designed exercise system.

  14. Heart rate reduction and longevity in mice.

    PubMed

    Gent, Sabine; Kleinbongard, Petra; Dammann, Philip; Neuhäuser, Markus; Heusch, Gerd

    2015-03-01

    Heart rate correlates inversely with life span across all species, including humans. In patients with cardiovascular disease, higher heart rate is associated with increased mortality, and such patients benefit from pharmacological heart rate reduction. However, cause-and-effect relationships between heart rate and longevity, notably in healthy individuals, are not established. We therefore prospectively studied the effects of a life-long pharmacological heart rate reduction on longevity in mice. We hypothesized, that the total number of cardiac cycles is constant, and that a 15% heart rate reduction might translate into a 15% increase in life span. C57BL6/J mice received either placebo or ivabradine at a dose of 50 mg/kg/day in drinking water from 12 weeks to death. Heart rate and body weight were monitored. Autopsy was performed on all non-autolytic cadavers, and parenchymal organs were evaluated macroscopically. Ivabradine reduced heart rate by 14% (median, interquartile range 12-15%) throughout life, and median life span was increased by 6.2% (p = 0.01). Body weight and macroscopic findings were not different between placebo and ivabradine. Life span was not increased to the same extent as heart rate was reduced, but nevertheless significantly prolonged by 6.2%.

  15. Heart rate dependency of JT interval sections.

    PubMed

    Hnatkova, Katerina; Johannesen, Lars; Vicente, Jose; Malik, Marek

    2017-08-09

    Little experience exists with the heart rate correction of J-Tpeak and Tpeak-Tend intervals. In a population of 176 female and 176 male healthy subjects aged 32.3±9.8 and 33.1±8.4years, respectively, curve-linear and linear relationship to heart rate was investigated for different sections of the JT interval defined by the proportions of the area under the vector magnitude of the reconstructed 3D vectorcardiographic loop. The duration of the JT sub-section between approximately just before the T peak and almost the T end was found heart rate independent. Most of the JT heart rate dependency relates to the beginning of the interval. The duration of the terminal T wave tail is only weakly heart rate dependent. The Tpeak-Tend is only minimally heart rate dependent and in studies not showing substantial heart rate changes does not need to be heart rate corrected. For any correction formula that has linear additive properties, heart rate correction of JT and JTpeak intervals is practically the same as of the QT interval. However, this does not apply to the formulas in the form of Int/RR(a) since they do not have linear additive properties. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Heart-Rate and Breath-Rate Monitor

    NASA Technical Reports Server (NTRS)

    Cooper, T. G.

    1983-01-01

    Circuit requiring only four integrated circuits (IC's) measures both heart rate and breath rate. Phase-locked loops lock on heart-rate and respiration-rate input signals. Each loop IC contains two phase comparators. Positive-edge-triggered circuit used in making monitors insensitive to dutycycle variations.

  17. Heart-Rate and Breath-Rate Monitor

    NASA Technical Reports Server (NTRS)

    Cooper, T. G.

    1983-01-01

    Circuit requiring only four integrated circuits (IC's) measures both heart rate and breath rate. Phase-locked loops lock on heart-rate and respiration-rate input signals. Each loop IC contains two phase comparators. Positive-edge-triggered circuit used in making monitors insensitive to dutycycle variations.

  18. Losartan improves heart rate variability and heart rate turbulence in heart failure due to ischemic cardiomyopathy.

    PubMed

    Ozdemir, Murat; Arslan, Uğur; Türkoğlu, Sedat; Balcioğlu, Serhat; Cengel, Atiye

    2007-12-01

    Heart rate variability (HRV) and heart rate turbulence are known to be disturbed and associated with excess mortality in heart failure. The aim of this study was to investigate whether losartan, when added on top of beta-blocker and angiotensin-converting enzyme inhibitor (ACEI) therapy, could improve these indices in patients with systolic heart failure. Seventy-seven patients (mean age 60.4 +/- 8.0, 80.5% male) with ischemic cardiomyopathy (mean ejection fraction 34.5 +/- 4.4%) and New York Heart Association Class II-III heart failure symptoms, already receiving a beta-blocker and an ACEI, were randomly assigned to either open-label losartan (losartan group) or no additional drug (control group) in a 2:1 ratio and the patients were followed for 12 weeks. The HRV and heart rate turbulence indices were calculated from 24-hour Holter recordings both at the beginning and at the end of follow-up. The baseline clinical characteristics, HRV, and heart rate turbulence indices were similar in the 2 groups. At 12 weeks of follow-up, all HRV parameters except pNN50 increased (SDNN: 113.2 +/- 34.2 versus 127.8 +/- 24.1, P = .001; SDANN: 101.5 +/- 31.7 versus 115.2 +/- 22.0, P = .001; triangular index: 29.9 +/- 11.1 versus 34.2 +/- 7.9, P = .008; RMSSD: 29.1 +/- 20.2 versus 34.3 +/- 23.0, P = .009; NN50: 5015.3 +/- 5554.9 versus 6446.7 +/- 6101.1, P = .024; NN50: 5.65 +/- 6.41 versus 7.24 +/- 6.99, P = .089; SDNNi: 45.1 +/- 13.3 versus 50.3 +/- 14.5, P = .004), turbulence onset decreased (-0. 61 +/- 1.70 versus -1.24 +/- 1.31, P = .003) and turbulence slope increased (4.107 +/- 3.881 versus 5.940 +/- 4.281, P = .004) significantly in the losartan group as compared with controls. A 12-week-long losartan therapy significantly improved HRV and heart rate turbulence in patients with Class II-III heart failure and ischemic cardiomyopathy already on beta-blockers and ACEI.

  19. Heart rate variability and swimming.

    PubMed

    Koenig, Julian; Jarczok, Marc N; Wasner, Mieke; Hillecke, Thomas K; Thayer, Julian F

    2014-10-01

    Professionals in the domain of swimming have a strong interest in implementing research methods in evaluating and improving training methods to maximize athletic performance and competitive outcome. Heart rate variability (HRV) has gained attention in research on sport and exercise to assess autonomic nervous system activity underlying physical activity and sports performance. Studies on swimming and HRV are rare. This review aims to summarize the current evidence on the application of HRV in swimming research and draws implications for future research. A systematic search of databases (PubMed via MEDLINE, PSYNDEX and Embase) according to the PRISMA statement was employed. Studies were screened for eligibility on inclusion criteria: (a) empirical investigation (HRV) in humans (non-clinical); (b) related to swimming; (c) peer-reviewed journal; and (d) English language. The search revealed 194 studies (duplicates removed), of which the abstract was screened for eligibility. Fourteen studies meeting the inclusion criteria were included in the review. Included studies broadly fell into three classes: (1) control group designs to investigate between-subject differences (i.e. swimmers vs. non-swimmers, swimmers vs. other athletes); (2) repeated measures designs on within-subject differences of interventional studies measuring HRV to address different modalities of training or recovery; and (3) other studies, on the agreement of HRV with other measures. The feasibility and possibilities of HRV within this particular field of application are well documented within the existing literature. Future studies, focusing on translational approaches that transfer current evidence in general practice (i.e. training of athletes) are needed.

  20. Heart Rate and Reinforcement Sensitivity in ADHD

    ERIC Educational Resources Information Center

    Luman, Marjolein; Oosterlaan, Jaap; Hyde, Christopher; van Meel, Catharina S.; Sergeant, Joseph A.

    2007-01-01

    Background: Both theoretical and clinical accounts of attention-deficit/hyperactivity disorder (ADHD) implicate a dysfunctional reinforcement system. This study investigated heart rate parameters in response to feedback associated with reward and response cost in ADHD children and controls aged 8 to 12. Methods: Heart rate responses (HRRs)…

  1. Heart Rate and Reinforcement Sensitivity in ADHD

    ERIC Educational Resources Information Center

    Luman, Marjolein; Oosterlaan, Jaap; Hyde, Christopher; van Meel, Catharina S.; Sergeant, Joseph A.

    2007-01-01

    Background: Both theoretical and clinical accounts of attention-deficit/hyperactivity disorder (ADHD) implicate a dysfunctional reinforcement system. This study investigated heart rate parameters in response to feedback associated with reward and response cost in ADHD children and controls aged 8 to 12. Methods: Heart rate responses (HRRs)…

  2. Heart Rates of Elite Synchronized Swimmers.

    ERIC Educational Resources Information Center

    Gemma, Karen Erickson; Wells, Christine L.

    1987-01-01

    Heart rates were recorded by radiotelemetry in ten elite and national-class synchronized swimmers as they performed competitive figures of high degrees of difficulty. The focus was on changes in heart rates and electrocardiogram patterns for each body position, especially those requiring facial immersion and breath-holding. (Author/MT)

  3. Heart Rates of Elite Synchronized Swimmers.

    ERIC Educational Resources Information Center

    Gemma, Karen Erickson; Wells, Christine L.

    1987-01-01

    Heart rates were recorded by radiotelemetry in ten elite and national-class synchronized swimmers as they performed competitive figures of high degrees of difficulty. The focus was on changes in heart rates and electrocardiogram patterns for each body position, especially those requiring facial immersion and breath-holding. (Author/MT)

  4. Heart rates of participants in wheelchair sports.

    PubMed

    Coutts, K D

    1988-02-01

    The relative stress of participation in wheelchair basketball, volleyball, tennis, and racquetball were determined by monitoring the heart rates of wheelchair athletes. Heart rates were recorded for 5 seconds every 30 seconds during monitoring sessions of 10 min or longer under game or practice conditions. Subjects were volunteer paraplegic athletes with lesions below T5 or with equivalent disability according to an international sport classification system. Average heart rates were 89 beats/min for tennis 'practice', 96 for racquetball 'practice' 107 for volleyball 'practice', 114 for volleyball 'game', 127 for tennis 'game', 129 for basketball 'practice', 135 for racquetball 'game', and 149 for basketball 'game' conditions. The percentage of time when heart rates were above 140 beats/min, followed the same pattern as the average heart rates and ranged from 0 to 62%.

  5. Development of the Jackson Heart Study Coordinating Center

    PubMed Central

    Campbell-Jenkins, Brenda W.; Addison, Clifton C.; Young, Lavon; Anugu, Pramod; Wilson, Gregory; Sarpong, Daniel

    2009-01-01

    The public health burden caused by cardiovascular disease (CVD) continues to adversely affect individuals in terms of cost, life expectancy, medical, pharmaceutical and hospital care. This burden has been excessive in the case of African Americans. The objective of this paper is to chronicle the procedures and processes that were implemented in the development of the Jackson Heart Study Coordinating Center. The Jackson Heart Study (JHS) is a population-based investigation of traditional and emerging risk factors that predict progression to CVD among African Americans. In response to the struggle against CVD, the Jackson Heart Study has convened a professional, technical, and administrative staff with specific competence in the operation of a coordinating center to handle the wide variety of areas related to CVD studies. The Jackson Heart Study Coordinating Center (JHSCC) was created to assure validity of the JHS findings and provide the resources necessary to meet comprehensive statistical needs (planning, implementing and monitoring data analysis); data management (designing, implementing and managing data collection and quality control), and administrative support. The JHSCC began with a commitment to support study functions in order to increase participant recruitment, retention and safety, meet regulatory requirements, prepare progress reports, and facilitate effective communication with the community and between all JHS centers. The JHSCC facilitates the efforts of the JHS scientists through the development and implementation of the study protocol. The efforts of the JHSCC have resulted in the successful preparation of scientific reports and manuscripts for publication and presentation of study findings and results. In summary, the JHSCC has emerged as an effective research mechanism that serves as the driving force behind the Jackson Heart Study activities. PMID:19543408

  6. Development of the Jackson Heart Study Coordinating Center.

    PubMed

    Campbell-Jenkins, Brenda W; Addison, Clifton C; Young, Lavon; Anugu, Pramod; Wilson, Gregory; Sarpong, Daniel

    2009-05-01

    The public health burden caused by cardiovascular disease (CVD) continues to adversely affect individuals in terms of cost, life expectancy, medical, pharmaceutical and hospital care. This burden has been excessive in the case of African Americans. The objective of this paper is to chronicle the procedures and processes that were implemented in the development of the Jackson Heart Study Coordinating Center. The Jackson Heart Study (JHS) is a population-based investigation of traditional and emerging risk factors that predict progression to CVD among African Americans. In response to the struggle against CVD, the Jackson Heart Study has convened a professional, technical, and administrative staff with specific competence in the operation of a coordinating center to handle the wide variety of areas related to CVD studies. The Jackson Heart Study Coordinating Center (JHSCC) was created to assure validity of the JHS findings and provide the resources necessary to meet comprehensive statistical needs (planning, implementing and monitoring data analysis); data management (designing, implementing and managing data collection and quality control), and administrative support. The JHSCC began with a commitment to support study functions in order to increase participant recruitment, retention and safety, meet regulatory requirements, prepare progress reports, and facilitate effective communication with the community and between all JHS centers. The JHSCC facilitates the efforts of the JHS scientists through the development and implementation of the study protocol. The efforts of the JHSCC have resulted in the successful preparation of scientific reports and manuscripts for publication and presentation of study findings and results. In summary, the JHSCC has emerged as an effective research mechanism that serves as the driving force behind the Jackson Heart Study activities.

  7. Resting heart rate estimation using PIR sensors

    NASA Astrophysics Data System (ADS)

    Kapu, Hemanth; Saraswat, Kavisha; Ozturk, Yusuf; Cetin, A. Enis

    2017-09-01

    In this paper, we describe a non-invasive and non-contact system of estimating resting heart rate (RHR) using a pyroelectric infrared (PIR) sensor. This infrared system monitors and records the chest motion of a subject using the analog output signal of the PIR sensor. The analog output signal represents the composite motion due to inhale-exhale process with magnitude much larger than the minute vibrations of heartbeat. Since the acceleration of the heart activity is much faster than breathing the second derivative of the PIR sensor signal monitoring the chest of the subject is used to estimate the resting heart rate. Experimental results indicate that this ambient sensor can measure resting heart rate with a chi-square significance level of α = 0.05 compared to an industry standard PPG sensor. This new system provides a low cost and an effective way to estimate the resting heart rate, which is an important biological marker.

  8. Association between heart rate variability and manual pulse rate.

    PubMed

    Hart, John

    2013-09-01

    One model for neurological assessment in chiropractic pertains to autonomic variability, tested commonly with heart rate variability (HRV). Since HRV may not be convenient to use on all patient visits, more user-friendly methods may help fill-in the gaps. Accordingly, this study tests the association between manual pulse rate and heart rate variability. The manual rates were also compared to the heart rate derived from HRV. Forty-eight chiropractic students were examined with heart rate variability (SDNN and mean heart rate) and two manual radial pulse rate measurements. Inclusion criteria consisted of participants being chiropractic students. Exclusion criteria for 46 of the participants consisted of a body mass index being greater than 30, age greater than 35, and history of: a) dizziness upon standing, b) treatment of psychiatric disorders, and c) diabetes. No exclusion criteria were applied to the remaining two participants who were also convenience sample volunteers. Linear associations between the manual pulse rate methods and the two heart rate variability measures (SDNN and mean heart) were tested with Pearson's correlation and simple linear regression. Moderate strength inverse (expected) correlations were observed between both manual pulse rate methods and SDNN (r = -0.640, 95% CI -0.781, -0.435; r = -0.632, 95% CI -0.776, -0.425). Strong direct (expected) relationships were observed between the manual pulse rate methods and heart rate derived from HRV technology (r = 0.934, 95% CI 0.885, 0.962; r = 0.941, 95% CI 0.897, 0.966). Manual pulse rates may be a useful option for assessing autonomic variability. Furthermore, this study showed a strong relationship between manual pulse rates and heart rate derived from HRV technology.

  9. Heart Rate and Respiratory Rate Influence on Heart Rate Variability Repeatability: Effects of the Correction for the Prevailing Heart Rate

    PubMed Central

    Gąsior, Jakub S.; Sacha, Jerzy; Jeleń, Piotr J.; Zieliński, Jakub; Przybylski, Jacek

    2016-01-01

    Background: Since heart rate variability (HRV) is associated with average heart rate (HR) and respiratory rate (RespRate), alterations in these parameters may impose changes in HRV. Hence the repeatability of HRV measurements may be affected by differences in HR and RespRate. The study aimed to evaluate HRV repeatability and its association with changes in HR and RespRate. Methods: Forty healthy volunteers underwent two ECG examinations 7 days apart. Standard HRV indices were calculated from 5-min ECG recordings. The ECG-derived respiration signal was estimated to assess RespRate. To investigate HR impact on HRV, HRV parameters were corrected for prevailing HR. Results: Differences in HRV parameters between the measurements were associated with the changes in HR and RespRate. However, in multiple regression analysis only HR alteration proved to be independent determinant of the HRV differences—every change in HR by 1 bpm changed HRV values by 16.5% on average. After overall removal of HR impact on HRV, coefficients of variation of the HRV parameters significantly dropped on average by 26.8% (p < 0.001), i.e., by the same extent HRV reproducibility improved. Additionally, the HRV correction for HR decreased association between RespRate and HRV. Conclusions: In stable conditions, HR but not RespRate is the most powerful factor determining HRV reproducibility and even a minimal change of HR may considerably alter HRV. However, the removal of HR impact may significantly improve HRV repeatability. The association between HRV and RespRate seems to be, at least in part, HR dependent. PMID:27588006

  10. How to Take Your Heart Rate

    MedlinePlus

    ... 140 135 Some medications may keep your heart rate from going too high. If you are taking medicine for your heart or blood pressure, check with your health care team about how hard you should exercise. www. move. va. gov Physical Activity Handouts • P09 ...

  11. FPGA Implementation of Heart Rate Monitoring System.

    PubMed

    Panigrahy, D; Rakshit, M; Sahu, P K

    2016-03-01

    This paper describes a field programmable gate array (FPGA) implementation of a system that calculates the heart rate from Electrocardiogram (ECG) signal. After heart rate calculation, tachycardia, bradycardia or normal heart rate can easily be detected. ECG is a diagnosis tool routinely used to access the electrical activities and muscular function of the heart. Heart rate is calculated by detecting the R peaks from the ECG signal. To provide a portable and the continuous heart rate monitoring system for patients using ECG, needs a dedicated hardware. FPGA provides easy testability, allows faster implementation and verification option for implementing a new design. We have proposed a five-stage based methodology by using basic VHDL blocks like addition, multiplication and data conversion (real to the fixed point and vice-versa). Our proposed heart rate calculation (R-peak detection) method has been validated, using 48 first channel ECG records of the MIT-BIH arrhythmia database. It shows an accuracy of 99.84%, the sensitivity of 99.94% and the positive predictive value of 99.89%. Our proposed method outperforms other well-known methods in case of pathological ECG signals and successfully implemented in FPGA.

  12. Elevated heart rate and nondipping heart rate as potential targets for melatonin: a review.

    PubMed

    Simko, Fedor; Baka, Tomas; Paulis, Ludovit; Reiter, Russel J

    2016-09-01

    Elevated heart rate is a risk factor for cardiovascular and all-cause mortalities in the general population and various cardiovascular pathologies. Insufficient heart rate decline during the night, that is, nondipping heart rate, also increases cardiovascular risk. Abnormal heart rate reflects an autonomic nervous system imbalance in terms of relative dominance of sympathetic tone. There are only a few prospective studies concerning the effect of heart rate reduction in coronary heart disease and heart failure. In hypertensive patients, retrospective analyses show no additional benefit of slowing down the heart rate by beta-blockade to blood pressure reduction. Melatonin, a secretory product of the pineal gland, has several attributes, which predict melatonin to be a promising candidate in the struggle against elevated heart rate and its consequences in the hypertensive population. First, melatonin production depends on the sympathetic stimulation of the pineal gland. On the other hand, melatonin inhibits the sympathetic system in several ways representing potentially the counter-regulatory mechanism to normalize excessive sympathetic drive. Second, administration of melatonin reduces heart rate in animals and humans. Third, the chronobiological action of melatonin may normalize the insufficient nocturnal decline of heart rate. Moreover, melatonin reduces the development of endothelial dysfunction and atherosclerosis, which are considered a crucial pathophysiological disorder of increased heart rate and pulsatile blood flow. The antihypertensive and antiremodeling action of melatonin along with its beneficial effects on lipid profile and insulin resistance may be of additional benefit. A clinical trial investigating melatonin actions in hypertensive patients with increased heart rate is warranted.

  13. Remote Measurements of Heart and Respiration Rates for Telemedicine

    PubMed Central

    Qian, Yi; Tsien, Joe Z.

    2013-01-01

    Non-contact and low-cost measurements of heart and respiration rates are highly desirable for telemedicine. Here, we describe a novel technique to extract blood volume pulse and respiratory wave from a single channel images captured by a video camera for both day and night conditions. The principle of our technique is to uncover the temporal dynamics of heart beat and breathing rate through delay-coordinate transformation and independent component analysis-based deconstruction of the single channel images. Our method further achieves robust elimination of false positives via applying ratio-variation probability distributions filtering approaches. Moreover, it enables a much needed low-cost means for preventing sudden infant death syndrome in new born infants and detecting stroke and heart attack in elderly population in home environments. This noncontact-based method can also be applied to a variety of animal model organisms for biomedical research. PMID:24115996

  14. Heart Rate Sensor for Freshwater Mussels

    NASA Astrophysics Data System (ADS)

    Just, C. L.; Vial, D. P.; Kruger, A.; Niemeier, J. J.; Lee, H. W.; Schroer, H. W.

    2014-12-01

    Researchers have long been interested the cardiac activity of mollusks. First, it is important as a basic measure of the animal's metabolism. Further, activities such as feeding and burrowing affect heart rate, as do environmental factors such as water salinity, water temperature, exposure, and predation. We have developed a small, noninvasive sensor for measuring freshwater mussel heart rate. Its working principle is as follows. An infrared (IR) light-emitting diode is placed in contact with the mussel shell. Some of the IR penetrates through the shell, reflects off internal organs, and traverses back. A photodetector detects this IR, and electronics condition the signal. The heartbeat of the animal modulates the IR, allowing one to measure the heart rate. The technique is widely-used in finger heart-rate monitors in humans. The sensors do not have to be positioned above the heart and several locations on the mussel shell work well. The sensor is small (8 mm × 10 mm) and consumes less than 1 mA, and has a simple one-wire interface that allows for easy integration into data acquisition hardware. We present heart rate measurements for the common pocketbook (lampsilis cardium) freshwater mussel.

  15. Heart rate recovery after exercise: an important prognostic criterion.

    PubMed

    Cay, Serkan

    2009-11-12

    Exercise stress testing gives important data about autonomic nervous system activity. It has been demonstrated that heart rate profile parameters such as resting heart rate before exercise, maximum heart rate at peak exercise, heart rate increment during exercise, and heart rate decrement after exercise (heart rate recovery) are important prognostic factors in a variety of patient population. These simply measured parameters give significant and valuable data about prognosis.

  16. Sound and vibration: effects on infants' heart rate and heart rate variability during neonatal transport.

    PubMed

    Karlsson, Björn-Markus; Lindkvist, Marie; Lindkvist, Markus; Karlsson, Marcus; Lundström, Ronnie; Håkansson, Stellan; Wiklund, Urban; van den Berg, Johannes

    2012-02-01

    To measure the effect of sound and whole-body vibration on infants' heart rate and heart rate variability during ground and air ambulance transport. Sixteen infants were transported by air ambulance with ground ambulance transport to and from the airports. Whole-body vibration and sound levels were recorded and heart parameters were obtained by ECG signal. Sound and whole-body vibration levels exceeded the recommended limits. Mean whole-body vibration and sound levels were 0.19 m/s(2) and 73 dBA, respectively. Higher whole-body vibration was associated with a lower heart rate (p < 0.05), and higher sound level was linked to a higher heart rate (p = 0.05). The heart rate variability was significantly higher at the end of the transport than at the beginning (p < 0.01). Poorer physiological status was associated with lower heart rate variability (p < 0.001) and a lower heart rate (p < 0.01). Infants wearing earmuffs had a lower heart rate (p < 0.05). Sound and whole-body vibration during neonatal transport exceed recommended levels for adults, and sound seem to have a more stressful effect on the infant than vibrations. Infants should wear earmuffs during neonatal transport because of the stress-reducing effect. © 2011 The Author(s)/Acta Paediatrica © 2011 Foundation Acta Paediatrica.

  17. Heart-rate pulse-shift detector

    NASA Technical Reports Server (NTRS)

    Anderson, M.

    1974-01-01

    Detector circuit accurately separates and counts phase-shift pulses over wide range of basic pulse-rate frequency, and also provides reasonable representation of full repetitive EKG waveform. Single telemeter implanted in small animal monitors not only body temperature but also animal movement and heart rate.

  18. Monitoring nocturnal heart rate with bed sensor.

    PubMed

    Migliorini, M; Kortelainen, J M; Pärkkä, J; Tenhunen, M; Himanen, S L; Bianchi, A M

    2014-01-01

    This article is part of the Focus Theme of Methods of Information in Medicine on "Biosignal Interpretation: Advanced Methods for Studying Cardiovascular and Respiratory Systems". The aim of this study is to assess the reliability of the estimated Nocturnal Heart Rate (HR), recorded through a bed sensor, compared with the one obtained from standard electrocardiography (ECG). Twenty-eight sleep deprived patients were recorded for one night each through matrix of piezoelectric sensors, integrated into the mattress, through polysomnography (PSG) simultaneously. The two recording methods have been compared in terms of signal quality and differences in heart beat detection. On average, coverage of 92.7% of the total sleep time was obtained for the bed sensor, testifying the good quality of the recordings. The average beat-to-beat error of the inter-beat intervals was 1.06%. These results suggest a good overall signal quality, however, considering fast heart rates (HR > 100 bpm), performances were worse: in fact, the sensitivity in the heart beat detection was 28.4% while the false positive rate was 3.8% which means that a large amount of fast beats were not detected. The accuracy of the measurements made using the bed sensor has less than 10% of failure rate especially in periods with HR lower than 70 bpm. For fast heart beats the uncertainty increases. This can be explained by the change in morphology of the bed sensor signal in correspondence of a higher HR.

  19. Heart Rate Variability Analysis in General Medicine

    PubMed Central

    Gang, Yi; Malik, Marek

    2003-01-01

    Autonomic nervous system plays an integral role in homeostasis. Autonomic modulation can frequently be altered in patients with cardiac disorders as well as in patients with other critical illnesses or injuries. Assessment of heart rate variability is based on analysis of consecutive normal R-R intervals and may provide quantitative information on the modulation of cardiac vagal and sympathetic nerve input. The hypothesis that depressed heart rate variability may occur over a broad range of illness and injury, and may inversely correlated with disease severity and outcome has been tested in various clinical settings over the last decade. This article reviews recent literature concerning the potential clinical implications and limitations of heart rate variability assessment in general medicine. PMID:16943988

  20. Resting Heart Rate and Auditory Evoked Potential

    PubMed Central

    Fiuza Regaçone, Simone; Baptista de Lima, Daiane Damaris; Engrácia Valenti, Vitor; Figueiredo Frizzo, Ana Cláudia

    2015-01-01

    The objective of this study was to evaluate the association between rest heart rate (HR) and the components of the auditory evoked-related potentials (ERPs) at rest in women. We investigated 21 healthy female university students between 18 and 24 years old. We performed complete audiological evaluation and measurement of heart rate for 10 minutes at rest (heart rate monitor Polar RS800CX) and performed ERPs analysis (discrepancy in frequency and duration). There was a moderate negative correlation of the N1 and P3a with rest HR and a strong positive correlation of the P2 and N2 components with rest HR. Larger components of the ERP are associated with higher rest HR. PMID:26504838

  1. Heart Rate and Electrocardiography Monitoring in Mice

    PubMed Central

    Ho, David; Zhao, Xin; Gao, Shumin; Hong, Chull; Vatner, Dorothy E.; Vatner, Stephen F.

    2011-01-01

    The majority of current cardiovascular research involves studies in genetically engineered mouse models. The measurement of heart rate is central to understanding cardiovascular control under normal conditions, with altered autonomic tone, superimposed stress or disease states, both in wild type mice as well as those with altered genes. Electrocardiography (ECG) is the “gold standard” using either hard wire or telemetry transmission. In addition, heart rate is measured or monitored from the frequency of the arterial pressure pulse or cardiac contraction, or by pulse oximetry. For each of these techniques, discussions of materials and methods, as well as advantages and limitations are covered. However, only the direct ECG monitoring will determine not only the precise heart rates but also whether the cardiac rhythm is normal or not. PMID:21743842

  2. Heart Rate Conditioning in Newborn Infants: Relationships Among Conditionability, Heart Rate Variability, and Sex

    ERIC Educational Resources Information Center

    Stamps, Leighton E.; Porges, Stephen W.

    1975-01-01

    Trace conditioning was evaluated in newborn infants by measurements of heart rate responses to a conditioned stimulus in anticipation of or in absence of the unconditioned stimulus. Data suggest females have higher levels of heart rate variability than males, which parallels their greater conditionability. (GO)

  3. Heart Rate Conditioning in Newborn Infants: Relationships Among Conditionability, Heart Rate Variability, and Sex

    ERIC Educational Resources Information Center

    Stamps, Leighton E.; Porges, Stephen W.

    1975-01-01

    Trace conditioning was evaluated in newborn infants by measurements of heart rate responses to a conditioned stimulus in anticipation of or in absence of the unconditioned stimulus. Data suggest females have higher levels of heart rate variability than males, which parallels their greater conditionability. (GO)

  4. Moxifloxacin Increases Heart Rate in Humans

    PubMed Central

    Mason, Jay W.; Moon, Thomas E.

    2017-01-01

    (1) Background: We assessed the effect of moxifloxacin on heart rate, and reviewed the heart rate effects of other antibiotics; (2) Methods: A total of 335 normal volunteers had 12-lead electrocardiograms recorded at multiple time points before and during treatment with moxifloxacin and with placebo in seven consecutive, thorough QT studies of crossover design; (3) Results: The average baseline heart rate across the seven studies was 61.5 bpm. The heart rate after moxifloxacin dosing was analyzed at five time points shared by all seven studies (hours 1, 2, 3, 12 and 24). The maximum mean heart rate (HR) increase for the seven studies combined was 2.4 bpm (95% CI 1.6, 3.3) at hour 2. The range of mean maximum increases among the seven studies was 2.1 to 4.3 bpm. For the seven studies combined, the increase was statistically significant at all but the 24 h time point. The maximum observed individual increase in HR was 36 bpm and the mean maximum increase was 30 ± 4.1 bpm by time point and 8 ± 6.9 bpm by subject. Many antibiotics increase HR, some several-fold more than moxifloxacin. However, clinicians and clinical investigators give little attention to this potential adverse effect in the medical literature; (4) Conclusions: The observed moxifloxacin-induced increase in HR is large enough to be clinically relevant, and it is a potentially important confounder in thorough QT studies using moxifloxacin as an active control. More attention to heart rate effects of antibiotics is warranted. PMID:28165431

  5. Heart rate profile during exercise in patients with early repolarization.

    PubMed

    Cay, Serkan; Cagirci, Goksel; Atak, Ramazan; Balbay, Yucel; Demir, Ahmet Duran; Aydogdu, Sinan

    2010-09-01

    Both early repolarization and altered heart rate profile are associated with sudden death. In this study, we aimed to demonstrate an association between early repolarization and heart rate profile during exercise. A total of 84 subjects were included in the study. Comparable 44 subjects with early repolarization and 40 subjects with normal electrocardiogram underwent exercise stress testing. Resting heart rate, maximum heart rate, heart rate increment and decrement were analyzed. Both groups were comparable for baseline characteristics including resting heart rate. Maximum heart rate, heart rate increment and heart rate decrement of the subjects in early repolarization group had significantly decreased maximum heart rate, heart rate increment and heart rate decrement compared to control group (all P < 0.05). The lower heart rate increment (< 106 beats/min) and heart rate decrement (< 95 beats/min) were significantly associated with the presence of early repolarization. After adjustment for age and sex, the multiple-adjusted OR of the risk of presence of early repolarization was 2.98 (95%CI 1.21-7.34) (P = 0.018) and 7.73 (95%CI 2.84-21.03) (P < 0.001) for the lower heart rate increment and heart rate decrement compared to higher levels, respectively. Subjects with early repolarization have altered heart rate profile during exercise compared to control subjects. This can be related to sudden death.

  6. Temporal Coordination and Adaptation to Rate Change in Music Performance

    ERIC Educational Resources Information Center

    Loehr, Janeen D.; Large, Edward W.; Palmer, Caroline

    2011-01-01

    People often coordinate their actions with sequences that exhibit temporal variability and unfold at multiple periodicities. We compared oscillator- and timekeeper-based accounts of temporal coordination by examining musicians' coordination of rhythmic musical sequences with a metronome that gradually changed rate at the end of a musical phrase…

  7. Temporal Coordination and Adaptation to Rate Change in Music Performance

    ERIC Educational Resources Information Center

    Loehr, Janeen D.; Large, Edward W.; Palmer, Caroline

    2011-01-01

    People often coordinate their actions with sequences that exhibit temporal variability and unfold at multiple periodicities. We compared oscillator- and timekeeper-based accounts of temporal coordination by examining musicians' coordination of rhythmic musical sequences with a metronome that gradually changed rate at the end of a musical phrase…

  8. Estimation of heart rate and heart rate variability from pulse oximeter recordings using localized model fitting.

    PubMed

    Wadehn, Federico; Carnal, David; Loeliger, Hans-Andrea

    2015-08-01

    Heart rate variability is one of the key parameters for assessing the health status of a subject's cardiovascular system. This paper presents a local model fitting algorithm used for finding single heart beats in photoplethysmogram recordings. The local fit of exponentially decaying cosines of frequencies within the physiological range is used to detect the presence of a heart beat. Using 42 subjects from the CapnoBase database, the average heart rate error was 0.16 BPM and the standard deviation of the absolute estimation error was 0.24 BPM.

  9. Heart Rate As a Biomarker in Heart Failure: Role of Heart Rate Lowering Agents.

    PubMed

    Shaaya, Ghazwan; Al-Khazaali, Ali; Arora, Rohit

    Heart failure (HF) is a common clinical condition affecting more than 5.8 million people in the United States, it remains the leading cause of death in the United States and worldwide. Ongoing challenges for biomarker identification include the need for objective assessment, measurement precision, and meaningful replication. Biomarkers not only serve as traditional predictors of prognosis, they can also help to identify high-risk patients who need closer monitoring and more aggressive therapy; therefore, we reviewed the use of heart rate (HR) as a biomarker in HF both of diagnostic and prognostic values, in addition, to being easily detected. HR is a determinant of myocardial oxygen demand, coronary blood flow, and myocardial performance and is central to the adaptation of cardiac output to metabolic needs. Increased HR is known to predict adverse outcome in the general population and in patients with chronic HF. Part of the ability of HR to predict risk is related to the forces driving it, namely, neurohormonal activation. We reviewed therapies, which slow the HR like β-blockers and ivabradine (a drug that is a pure HR-reducing agent), and all the clinical studies suggest the benefit of these drugs in the management of HF, and increasing evidence suggests HR as a biomarker of both diagnostic and prognostic values in HF.

  10. Heart Rate Variability and Cardiovascular Reactivity in Panic Disorder

    DTIC Science & Technology

    1999-04-01

    heart rate reactivity to cold pressor , CO2 and mental arithmetic (Roth et aI., 1992) and orthostatic... heart rates in panic disorder are inconsistent. The decreased heart rate responses to commonly used stressors, such as cold pressor , may indicate that...cardiovascular activation and heart rate variability during naturalistic anxiety and panic. Specific hypotheses to be tested included: HyPOthesis

  11. H2-blocker modulates heart rate variability.

    PubMed

    Ooie, T; Saikawa, T; Hara, M; Ono, H; Seike, M; Sakata, T

    1999-01-01

    The use of H2-blockers in the treatment of patients with peptic ulcer has become popular. However, this treatment has adverse cardiovascular effects. The aim of this study was to investigate proarrhythmic rhythm and autonomic nervous activity by analyzing heart rate variability in patients treated with omeprazole, ranitidine, and plaunotol. Nineteen patients (mean age 67.5 +/- 2.7 years) with active gastric ulcer were treated with omeprazole (20 mg/day) for 8 weeks, then ranitidine (300 mg/day) for the next 4 months, and finally plaunotol (240 mg/day). At each stage of the treatment, Holter electrocardiography was performed, and heart rate variability and arrhythmias analyzed. Heart rate variability yielded power in the low- (0.04-0.15 Hz) and high-frequency components (0.15-0.4 Hz). Although both ranitidine and omeprazole induced little change in cardiac rhythm, the high-frequency power was higher (10.3 +/- 0.8 vs 8.6 +/- 0.6 ms, P < 0.05) and the ratio of low-to-high frequency power was lower (1.41 +/-0.10 vs 1.59 +/- 0.09. P < 0.05) during ranitidine than during plaunotol treatment. Cosinor analysis of heart rate variability revealed a decreased amplitude of low-frequency power during omeprazole compared with during ranitidine and plaunotol treatment. Ranitidine modulated high-frequency power which may be related to the adverse cardiovascular effects of H2-blocker.

  12. Parenting Behaviors, Parent Heart Rate Variability, and Their Associations with Adolescent Heart Rate Variability.

    PubMed

    Graham, Rebecca A; Scott, Brandon G; Weems, Carl F

    2016-11-30

    Adolescence is a potentially important time in the development of emotion regulation and parenting behaviors may play a role. We examined associations among parenting behaviors, parent resting heart rate variability, adolescent resting heart rate variability and parenting behaviors as moderators of the association between parent and adolescent resting heart rate variability. Ninety-seven youth (11-17 years; 49.5 % female; 34 % African American, 37.1 % Euro-American, 22.6 % other/mixed ethnic background, and 7.2 % Hispanic) and their parents (n = 81) completed a physiological assessment and questionnaires assessing parenting behaviors. Inconsistent discipline and corporal punishment were negatively associated with adolescent resting heart rate variability, while positive parenting and parental involvement were positively associated. Inconsistent discipline and parental involvement moderated the relationship between parent and adolescent resting heart rate variability. The findings provide evidence for a role of parenting behaviors in shaping the development of adolescent resting heart rate variability with inconsistent discipline and parental involvement potentially influencing the entrainment of resting heart rate variability in parents and their children.

  13. Reproducibility of heart rate turbulence indexes in heart failure patients.

    PubMed

    D'Addio, Gianni; Cesarelli, Mario; Corbi, Graziamaria; Romano, Maria; Furgi, Giuseppe; Ferrara, Nicola; Rengo, Franco

    2010-01-01

    Cardiovascular oscillations following spontaneous ventricular premature complexes (VPC) are characterized by a short-term heart rate fluctuation known as heart rate turbulence (HRT) described by the so-called turbulence onset (TO) and slope (TS). Despite a recent written consensus on the standard of HRT measurement, reproducibility data are lacking. Aim of the paper was a reproducibility study of HRT indexes in heart failure patients (HF). Eleven HF patients underwent two 24h ECG Holter recordings, spaced 7 ± 5 days. A paired t test was used to assess the clinical stability of patients during the study period and the number of PVC in Holter recordings' couples. Both TO and TS indexes were calculated for each isolated VPC, and due to their skewed distribution, reproducibility of median and mean TO and TS was studied by Bland-Altman technique. Results showed that median HRT indexes might be preferred to commonly suggested mean values and that, although TO showed lower bias value than TS, TS can be considered much more reproducible than TO, comparing limits of agreements with normal values. This preliminary results suggest the use of medians instead of mean HRT indexes values and a reliability of the turbulence slope greater than the turbulence onset index.

  14. Lessons from the Heart: Individualizing Physical Education with Heart Rate Monitors.

    ERIC Educational Resources Information Center

    Kirkpatrick, Beth; Birnbaum, Burton H.

    Learning about the relationship between heart rate and physical activity is an important aspect of fitness education. Use of a heart rate monitor (HRM) helps a student to understand how stretching and large muscle movements gradually increase the heart rate and blood flow, and enables students to measure their exercise heart rates and set goals…

  15. Lessons from the Heart: Individualizing Physical Education with Heart Rate Monitors.

    ERIC Educational Resources Information Center

    Kirkpatrick, Beth; Birnbaum, Burton H.

    Learning about the relationship between heart rate and physical activity is an important aspect of fitness education. Use of a heart rate monitor (HRM) helps a student to understand how stretching and large muscle movements gradually increase the heart rate and blood flow, and enables students to measure their exercise heart rates and set goals…

  16. Heart Rate Variability – A Historical Perspective

    PubMed Central

    Billman, George E.

    2011-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R–R interval – the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration – the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the “Physician’s Pulse Watch” (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV. PMID:22144961

  17. Impact of exercise on heart rate recovery.

    PubMed

    Jolly, Michael A; Brennan, Danielle M; Cho, Leslie

    2011-10-04

    Abnormal heart rate recovery (HRR) has been shown to predict mortality. Although small studies have found that HRR can be improved with cardiac rehabilitation, it is unknown whether an improvement would affect mortality. The aim of this study was to determine whether HRR could be improved with cardiac rehabilitation and whether it would be predictive of mortality. We evaluated 1070 consecutive patients who underwent exercise stress testing before and after completion of a phase 2 cardiac rehabilitation program. Heart rate recovery, defined as the difference between heart rate at peak exercise and exactly 1 minute into the recovery period, and mortality were followed up as the primary end points. Of 544 patients with abnormal baseline HRR, 225 (41%) had normal HRR after rehabilitation. Of the entire cohort, 197 patients (18%) died. Among patients with an abnormal HRR at baseline, failure to normalize after rehabilitation predicted a higher mortality (P<0.001). After multivariable adjustment, the presence of an abnormal HRR at exit was predictive of death in all patients (hazard ratio, 2.15; 95% confidence interval 1.43-3.25). Patients with abnormal HRR at baseline who normalized afterward had survival rates similar to those of the group with normal HRR at baseline and after cardiac rehabilitation (P=0.143). Heart rate recovery improved after phase 2 cardiac rehabilitation in the overall cohort. There was a strong association of abnormal HRR at exit with all-cause mortality. Patients with abnormal HRR at baseline who normalized HRR with exercise had a mortality similar to that of individuals with baseline normal HRR.

  18. [Heart rate variability. Applications in psychiatry].

    PubMed

    Servant, D; Logier, R; Mouster, Y; Goudemand, M

    2009-10-01

    The autonomic nervous system sends messages through the sympathetic and parasympathetic nervous system. The sympathetic nervous system innervates the cardioaccelerating center of the heart, the lungs (increased ventilatory rhythm and dilatation of the bronchi) and the non-striated muscles (artery contraction). It releases adrenaline and noradrenaline. As opposed to the sympathetic nervous system, it innervates the cardiomoderator center of the heart, the lungs (slower ventilatory rhythm and contraction of the bronchi) and the non-striated muscles (artery dilatation). It uses acetylcholine (ACh) as its neurotransmitter. Sympathetic and parasympathetic divisions function antagonistically to preserve a dynamic modulation of vital functions. These systems act on the heart respectively through the stellar ganglion and the vagus nerve. The interaction of these messages towards the sinoauricular node is responsible for normal cardiac variability, which can be measured by monitoring heart rate variability (HRV). Heart rate is primarily controlled by vagal activity. Sensorial data coming from the heart are fed back to the central nervous system. HRV is an indicator of both how the central nervous system regulates the autonomic nervous system, and of how peripheral neurons feed information back to the central level. HRV measures are derived by estimating the variation among a set of temporally ordered interbeat intervals. The state of perfect symmetry, which, in medical parlance, is called respiratory sinus arrhythmia (RSA), can be described as a state of cardiac coherence. Obtaining a series of interbeat intervals requires a continuous measure of heart rate, typically electrocardiography (ECG). Commercially available software is then used to define the interbeat intervals within an ECG recording. The autonomic nervous system is highly adaptable and allows the organism to maintain its balance when experiencing strain or stress. Conversely, a lack of flexibility and a rigid

  19. Heart rate recovery and heart rate complexity following resistance exercise training and detraining in young men.

    PubMed

    Heffernan, Kevin S; Fahs, Christopher A; Shinsako, Kevin K; Jae, Sae Young; Fernhall, Bo

    2007-11-01

    The purpose of this study was to examine heart rate recovery (HRR) and linear/nonlinear heart rate variability (HRV) before and after resistance training. Fourteen young men (25.0 +/- 1.1 yr of age) completed a crossover design consisting of a 4-wk time-control period, 6 wk of resistance training (3 days/wk), and 4 wk of detraining. Linear HRV was spectrally decomposed using an autoregressive approach. Nonlinear dynamics of heart rate complexity included sample entropy (SampEn) and Lempel-Ziv entropy (LZEn). HRR was calculated from a graded maximal exercise test as maximal heart rate attained during the test minus heart rate at 1 min after exercise (HRR). There was no change in SampEn, LZEn, or HRR after the time-control portion of the study (P > 0.05). SampEn (P < 0.05), LZEn (P < 0.05), and HRR (P < 0.05) increased after resistance training and returned to pretraining values after detraining. There was no change in spectral measures of HRV at any time point (P > 0.05). These findings suggest that resistance exercise training increases heart rate complexity and HRR after exercise but has no effect on spectral measures of HRV in young healthy men. These autonomic changes regress shortly after cessation of training.

  20. Heart Rate and Heart Rate Variability in Parents at Risk for Child Physical Abuse.

    PubMed

    Crouch, Julie L; Hiraoka, Regina; McCanne, Thomas R; Reo, Gim; Wagner, Michael F; Krauss, Alison; Milner, Joel S; Skowronski, John J

    2015-12-10

    The present study examined heart rate and heart rate variability (i.e., respiratory sinus arrhythmia [RSA]) in a sample of 48 general population parents (41.7% fathers), who were either at high risk (n = 24) or low risk (n = 24) for child physical abuse. During baseline assessments of heart rate and RSA, parents sat quietly for 3 min. Afterward, parents were presented with a series of anagrams (either easy or difficult) and were instructed to solve as many anagrams as possible in 3 min. As expected, high-risk (compared with low-risk) parents evinced significantly higher resting heart rate and significantly lower resting RSA. During the anagram task, high-risk parents did not evince significant changes in heart rate or RSA relative to baseline levels. In contrast, low-risk parents evinced significant increases in heart rate and significant decreases in RSA during the anagram task. Contrary to expectations, the anagram task difficulty did not moderate the study findings. Collectively, this pattern of results is consistent with the notion that high-risk parents have chronically higher levels of physiological arousal relative to low-risk parents and exhibit less physiological flexibility in response to environmental demands. High-risk parents may benefit from interventions that include components that reduce physiological arousal and increase the capacity to regulate arousal effectively. © The Author(s) 2015.

  1. Modeling heart rate variability by stochastic feedback

    NASA Technical Reports Server (NTRS)

    Amaral, L. A.; Goldberger, A. L.; Stanley, H. E.

    1999-01-01

    We consider the question of how the cardiac rhythm spontaneously self-regulates and propose a new mechanism as a possible answer. We model the neuroautonomic regulation of the heart rate as a stochastic feedback system and find that the model successfully accounts for key characteristics of cardiac variability, including the 1/f power spectrum, the functional form and scaling of the distribution of variations of the interbeat intervals, and the correlations in the Fourier phases which indicate nonlinear dynamics.

  2. Homeopathic effect on heart rate variability.

    PubMed

    Ruiz, G; Torres, J L; Michel, O; Navarro, R

    1999-07-01

    We record ECGs from healthy human subjects during 24-h long intervals, using ambulatory equipment. We calculate from the data various parameters, searching for those that change in a clear and systematic way under a homeopathic stimulus, (Strophantus hispidus 30c). The energy fraction at high frequencies in the power spectrum of heart rate variability fulfills this condition, and we are able to interpret our results in a way consistent with the information on this medicine in the homeopathic Materia Medica.

  3. Multiscale power analysis for heart rate variability

    NASA Astrophysics Data System (ADS)

    Zeng, Peng; Liu, Hongxing; Ni, Huangjing; Zhou, Jing; Xia, Lan; Ning, Xinbao

    2015-06-01

    We first introduce multiscale power (MSP) method to assess the power distribution of physiological signals on multiple time scales. Simulation on synthetic data and experiments on heart rate variability (HRV) are tested to support the approach. Results show that both physical and psychological changes influence power distribution significantly. A quantitative parameter, termed power difference (PD), is introduced to evaluate the degree of power distribution alteration. We find that dynamical correlation of HRV will be destroyed completely when PD>0.7.

  4. Modeling heart rate variability by stochastic feedback

    NASA Technical Reports Server (NTRS)

    Amaral, L. A.; Goldberger, A. L.; Stanley, H. E.

    1999-01-01

    We consider the question of how the cardiac rhythm spontaneously self-regulates and propose a new mechanism as a possible answer. We model the neuroautonomic regulation of the heart rate as a stochastic feedback system and find that the model successfully accounts for key characteristics of cardiac variability, including the 1/f power spectrum, the functional form and scaling of the distribution of variations of the interbeat intervals, and the correlations in the Fourier phases which indicate nonlinear dynamics.

  5. Bluetooth Heart Rate Monitors For Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, R. E.; West, M. R.; Kalogera, K. L.; Hanson, A. M.

    2016-01-01

    Heart rate monitoring is required for crewmembers during exercise aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data are required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth heart rate monitors (BT_HRM) and their ability to provide high quality heart rate data to monitor crew health aboard the ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT_HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) were worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT_HRM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the 2 data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. RESULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6% error), followed by CS4 (3.3% error), CS3 (6.4% error), and CS2 (9.2% error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, but unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to obtain the best quality data. CS2 will be

  6. Rowing Crew Coordination Dynamics at Increasing Stroke Rates

    PubMed Central

    2015-01-01

    In rowing, perfect synchronisation is important for optimal performance of a crew. Remarkably, a recent study on ergometers demonstrated that antiphase crew coordination might be mechanically more efficient by reducing the power lost to within-cycle velocity fluctuations of the boat. However, coupled oscillator dynamics predict the stability of the coordination to decrease with increasing stroke rate, which in case of antiphase may eventually yield breakdowns to in-phase. Therefore, this study examined the effects of increasing stroke rate on in- and antiphase crew coordination in rowing dyads. Eleven experienced dyads rowed on two mechanically coupled ergometers on slides, which allowed the ergometer system to move back and forth as one ‘boat’. The dyads performed a ramp trial in both in- and antiphase pattern, in which stroke rates gradually increased from 30 strokes per minute (spm) to as fast as possible in steps of 2 spm. Kinematics of rowers, handles and ergometers were captured. Two dyads showed a breakdown of antiphase into in-phase coordination at the first stroke rate of the ramp trial. The other nine dyads reached between 34–42 spm in antiphase but achieved higher rates in in-phase. As expected, the coordinative accuracy in antiphase was worse than in in-phase crew coordination, while, somewhat surprisingly, the coordinative variability did not differ between the patterns. Whereas crew coordination did not substantially deteriorate with increasing stroke rate, stroke rate did affect the velocity fluctuations of the ergometers: fluctuations were clearly larger in the in-phase pattern than in the antiphase pattern, and this difference significantly increased with stroke rate. Together, these results suggest that although antiphase rowing is less stable (i.e., less resistant to perturbation), potential on-water benefits of antiphase over in-phase rowing may actually increase with stroke rate. PMID:26185987

  7. Case Studies in Electronic Fetal Heart Rate Monitoring

    PubMed Central

    Yee, J.; Parboosingh, I.J.

    1986-01-01

    Subtle changes in the characteristics of the fetal heart rate are currently used to assess the condition of the fetus in late pregnancy and during labour. The authors present three case studies of fetal heart rate monitoring. PMID:21267323

  8. The mitochondrial uniporter controls fight or flight heart rate increases.

    PubMed

    Wu, Yuejin; Rasmussen, Tyler P; Koval, Olha M; Joiner, Mei-Ling A; Hall, Duane D; Chen, Biyi; Luczak, Elizabeth D; Wang, Qiongling; Rokita, Adam G; Wehrens, Xander H T; Song, Long-Sheng; Anderson, Mark E

    2015-01-20

    Heart rate increases are a fundamental adaptation to physiological stress, while inappropriate heart rate increases are resistant to current therapies. However, the metabolic mechanisms driving heart rate acceleration in cardiac pacemaker cells remain incompletely understood. The mitochondrial calcium uniporter (MCU) facilitates calcium entry into the mitochondrial matrix to stimulate metabolism. We developed mice with myocardial MCU inhibition by transgenic expression of a dominant-negative (DN) MCU. Here, we show that DN-MCU mice had normal resting heart rates but were incapable of physiological fight or flight heart rate acceleration. We found that MCU function was essential for rapidly increasing mitochondrial calcium in pacemaker cells and that MCU-enhanced oxidative phoshorylation was required to accelerate reloading of an intracellular calcium compartment before each heartbeat. Our findings show that MCU is necessary for complete physiological heart rate acceleration and suggest that MCU inhibition could reduce inappropriate heart rate increases without affecting resting heart rate.

  9. BIOPHYSICAL CHARACTERISATION OF THE UNDER-APPRECIATED AND IMPORTANT RELATIONSHIP BETWEEN HEART RATE VARIABILITY AND HEART RATE

    PubMed Central

    Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

    2014-01-01

    Heart rate variability (beat-to-beat changes in the RR interval) has attracted considerable attention over the last 30+ years (PubMed currently lists >17,000 publications). Clinically, a decrease in heart rate variability is correlated to higher morbidity and mortality in diverse conditions, from heart disease to foetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated heart rate variability parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart and single sinoatrial nodal cell) in diverse species, combining this with data from previously published papers. We show that regardless of conditions, there is a universal exponential decay-like relationship between heart rate variability and heart rate. Using two biophysical models, we develop a theory for this, and confirm that heart rate variability is primarily dependent on heart rate and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in heart rate variability and altered morbidity and mortality is substantially attributable to the concurrent change in heart rate. This calls for re-evaluation of the findings from many papers that have not adjusted properly or at all for heart rate differences when comparing heart rate variability in multiple circumstances. PMID:25225208

  10. Passive fetal heart rate monitoring apparatus and method with enhanced fetal heart beat discrimination

    NASA Technical Reports Server (NTRS)

    Zahorian, Stephen A. (Inventor); Livingston, David L. (Inventor); Pretlow, Robert A., III (Inventor)

    1994-01-01

    An apparatus for acquiring signals emitted by a fetus, identifying fetal heart beats and determining a fetal heart rate is presented. Multiple sensor signals are outputted by a passive fetal heart rate monitoring sensor. Multiple parallel nonlinear filters filter these multiple sensor signals to identify fetal heart beats in the signal data. A processor determines a fetal heart rate based on these identified fetal heart beats. The processor includes the use of a figure of merit weighting of heart rate estimates based on the identified heart beats from each filter for each signal. The fetal heart rate thus determined is outputted to a display, storage, or communications channel. A method for enhanced fetal heart beat discrimination includes acquiring signals from a fetus, identifying fetal heart beats from the signals by multiple parallel nonlinear filtering, and determining a fetal heart rate based on the identified fetal heart beats. A figure of merit operation in this method provides for weighting a plurality of fetal heart rate estimates based on the identified fetal heart beats and selecting the highest ranking fetal heart rate estimate.

  11. Passive fetal heart rate monitoring apparatus and method with enhanced fetal heart beat discrimination

    NASA Technical Reports Server (NTRS)

    Zahorian, Stephen A. (Inventor); Livingston, David L. (Inventor); Pretlow, III, Robert A. (Inventor)

    1996-01-01

    An apparatus for acquiring signals emitted by a fetus, identifying fetal heart beats and determining a fetal heart rate. Multiple sensor signals are outputted by a passive fetal heart rate monitoring sensor. Multiple parallel nonlinear filters filter these multiple sensor signals to identify fetal heart beats in the signal data. A processor determines a fetal heart rate based on these identified fetal heart beats. The processor includes the use of a figure of merit weighting of heart rate estimates based on the identified heart beats from each filter for each signal. The fetal heart rate thus determined is outputted to a display, storage, or communications channel. A method for enhanced fetal heart beat discrimination includes acquiring signals from a fetus, identifying fetal heart beats from the signals by multiple parallel nonlinear filtering, and determining a fetal heart rate based on the identified fetal heart beats. A figure of merit operation in this method provides for weighting a plurality of fetal heart rate estimates based on the identified fetal heart beats and selecting the highest ranking fetal heart rate estimate.

  12. Mental workload classification using heart rate metrics.

    PubMed

    Henelius, Andreas; Hirvonen, Kati; Holm, Anu; Korpela, Jussi; Muller, Kiti

    2009-01-01

    The ability of different short-term heart rate variability metrics to classify the level of mental workload (MWL) in 140 s segments was studied. Electrocardiographic data and event related potentials (ERPs), calculated from electroencephalographic data, were collected from 13 healthy subjects during the performance of a computerised cognitive multitask test with different task load levels. The amplitude of the P300 component of the ERPs was used as an objective measure of MWL. Receiver operating characteristics analysis (ROC) showed that the time domain metric of average interbeat interval length was the best-performing metric in terms of classification ability.

  13. Acoustically based fetal heart rate monitor

    NASA Technical Reports Server (NTRS)

    Baker, Donald A.; Zuckerwar, Allan J.

    1991-01-01

    The acoustically based fetal heart rate monitor permits an expectant mother to perform the fetal Non-Stress Test in her home. The potential market would include the one million U.S. pregnancies per year requiring this type of prenatal surveillance. The monitor uses polyvinylidene fluoride (PVF2) piezoelectric polymer film for the acoustic sensors, which are mounted in a seven-element array on a cummerbund. Evaluation of the sensor ouput signals utilizes a digital signal processor, which performs a linear prediction routine in real time. Clinical tests reveal that the acoustically based monitor provides Non-Stress Test records which are comparable to those obtained with a commercial ultrasonic transducer.

  14. Heart-Rate Variability-More than Heart Beats?

    PubMed

    Ernst, Gernot

    2017-01-01

    Heart-rate variability (HRV) is frequently introduced as mirroring imbalances within the autonomous nerve system. Many investigations are based on the paradigm that increased sympathetic tone is associated with decreased parasympathetic tone and vice versa. But HRV is probably more than an indicator for probable disturbances in the autonomous system. Some perturbations trigger not reciprocal, but parallel changes of vagal and sympathetic nerve activity. HRV has also been considered as a surrogate parameter of the complex interaction between brain and cardiovascular system. Systems biology is an inter-disciplinary field of study focusing on complex interactions within biological systems like the cardiovascular system, with the help of computational models and time series analysis, beyond others. Time series are considered surrogates of the particular system, reflecting robustness or fragility. Increased variability is usually seen as associated with a good health condition, whereas lowered variability might signify pathological changes. This might explain why lower HRV parameters were related to decreased life expectancy in several studies. Newer integrating theories have been proposed. According to them, HRV reflects as much the state of the heart as the state of the brain. The polyvagal theory suggests that the physiological state dictates the range of behavior and psychological experience. Stressful events perpetuate the rhythms of autonomic states, and subsequently, behaviors. Reduced variability will according to this theory not only be a surrogate but represent a fundamental homeostasis mechanism in a pathological state. The neurovisceral integration model proposes that cardiac vagal tone, described in HRV beyond others as HF-index, can mirror the functional balance of the neural networks implicated in emotion-cognition interactions. Both recent models represent a more holistic approach to understanding the significance of HRV.

  15. Heart-Rate Variability—More than Heart Beats?

    PubMed Central

    Ernst, Gernot

    2017-01-01

    Heart-rate variability (HRV) is frequently introduced as mirroring imbalances within the autonomous nerve system. Many investigations are based on the paradigm that increased sympathetic tone is associated with decreased parasympathetic tone and vice versa. But HRV is probably more than an indicator for probable disturbances in the autonomous system. Some perturbations trigger not reciprocal, but parallel changes of vagal and sympathetic nerve activity. HRV has also been considered as a surrogate parameter of the complex interaction between brain and cardiovascular system. Systems biology is an inter-disciplinary field of study focusing on complex interactions within biological systems like the cardiovascular system, with the help of computational models and time series analysis, beyond others. Time series are considered surrogates of the particular system, reflecting robustness or fragility. Increased variability is usually seen as associated with a good health condition, whereas lowered variability might signify pathological changes. This might explain why lower HRV parameters were related to decreased life expectancy in several studies. Newer integrating theories have been proposed. According to them, HRV reflects as much the state of the heart as the state of the brain. The polyvagal theory suggests that the physiological state dictates the range of behavior and psychological experience. Stressful events perpetuate the rhythms of autonomic states, and subsequently, behaviors. Reduced variability will according to this theory not only be a surrogate but represent a fundamental homeostasis mechanism in a pathological state. The neurovisceral integration model proposes that cardiac vagal tone, described in HRV beyond others as HF-index, can mirror the functional balance of the neural networks implicated in emotion–cognition interactions. Both recent models represent a more holistic approach to understanding the significance of HRV. PMID:28955705

  16. Heart rate dynamics in a marsupial hibernator.

    PubMed

    Swoap, Steven J; Körtner, Gerhard; Geiser, Fritz

    2017-08-15

    The eastern pygmy possum (Cercartetus nanus) is a small marsupial that can express spontaneous short bouts of torpor, as well as multi-day bouts of deep hibernation. To examine heart rate (fH) control at various stages of torpor in a marsupial hibernator, and to see whether fH variability differs from that of deep placental hibernators, we used radiotelemetry to measure ECG and body temperature (Tb) while measuring the rate of O2 consumption and ventilation. fH and O2 consumption rate during euthermia were at a minimum (321±34 beats min(-1), 0.705±0.048 ml O2 g(-1) h(-1)) at an ambient temperature (Ta) of 31°C. fH had an inverse linear relationship with Ta to a maximum of 630±19 beats min(-1) at a Ta of 20°C. During entry into torpor at a Ta of 20°C, fH slowed primarily as a result of episodic periods of cardiac activity where electrical activity of the heart occurred in groups of 3 or 4 heart beats. When Tb was stable at 24°C in these torpor bouts, the episodic nature of fH had disappeared (i.e. no asystoles) with a rate of 34±3 beats min(-1) For multi-day bouts of deep torpor, Ta was lowered to 6.6±0.8°C. During these deep bouts of torpor, Tb reached a minimum of 8.0±1.0°C, with a minimum fH of 8 beats min(-1) and a minimum O2 consumption rate of 0.029±0.07 ml O2 g(-1) h(-1) Shivering bouts occurred in deep torpor about every 8 min, during which ventilation occurred, and fH was elevated to 40 beats min(-1) The duration of the QRS complex increased from 12 ms during euthermia to 69 ms at a Tb of 8°C. These findings demonstrate the dynamic functioning range of fH to be about 600 beats min(-1) (∼80-fold), one of the largest known ranges in mammals. Our study shows that despite a separation of ∼160 million years, the control and function of the cardiac system seems indistinguishable in marsupial and placental hibernating mammals. © 2017. Published by The Company of Biologists Ltd.

  17. Aerobic Fitness, Heart Rate Recovery and Heart Rate Recovery Time in Indian School Children.

    PubMed

    Fernando, Rajesh Jeniton; Ravichandran, K; Vaz, Mario

    2015-01-01

    Data on aerobic fitness and heart rate recovery in children are limited. This study was done to evaluate the relation between them in Indian school going children. Three hundred children of 7 to 10.5 years were recruited and their aerobic fitness was predicted using modified Harvard's step test (VO₂max) and 20 meter shuttle test (VO₂peak). The heart rate was monitored for 12 minutes post modified Harvard's step test. The difference between the maximum and the 1st minute HR was noted as HRR1 and the time taken to reach the resting heart rate was also recorded. VO₂max was inversely correlated with HRR1 (r = -0.64, p<0.001). However, the partial correlation of the two was not significant (r(partial) = -0.037, p = 0.55), indicating children with higher basal HR had higher HRR1 and that accounted for the observed association with aerobic fitness. Cox regression analysis showed that the recovery rate per unit time was 3% greater with increasing VO₂max (HR = 1.03, 95% CI:1.01 to 1.05, p = 0.013). The heart rate parameters did not show any associat with VO₂peak This study demonstrates that there is no relation between VO₂max and HRR1 after 3 minutes of modified Harvard's step test in Indian children of 7 to 10.5 years. However, aerobic fitness is a positive predictor of heart rate recovery time in this group.

  18. The heart rate VO2 relationship of aerobic dance: a comparison of target heart rate methods.

    PubMed

    Scharff-Olson, M; Williford, H N; Smith, F H

    1992-12-01

    The purpose of this study was to examine the relationship between heart rate (HR) and oxygen consumption (VO2) for aerobic dance exercise. Therefore, eleven females completed 20 minutes of aerobic dance with continuous monitoring of HR and VO2. These physiological responses were analyzed with correlation/regression techniques. The results showed that for aerobic dance to produce a response in excess of 50% of VO2 max, the target HR must be approximately 80% of the age-predicted HR max or greater. In contrast, previously reported data for treadmill running shows that 50% of VO2 max is achieved at approximately 65% of age-predicted HR max in females. The maximum heart rate reserve (Karvonen) method was also found to underestimate the actual VO2 of AD. With the Karvonen method, the target heart rate must approximate 65% of maximum HR reserve in order to elicit a VO2 response which is representative of 50% of VO2 max. These data support recent research which illustrates that target heart rate prescriptions derived from treadmill testing may fail to accurately place AD participants in the recommended training zone.

  19. Heart rate and heart rate variability responses to Tai Chi and jogging in Beijing and Graz.

    PubMed

    Litscher, Gerhard; Zhang, Weibo; Huang, Tao; Wang, Lu

    2011-02-01

    Tai Chi is a famous training method in China, and jogging is a popular kind of exercise both in Austria and China. Nevertheless, there is little information concerning online monitoring of biosignals during both training activities in parallel. Within the last years innovative scientific monitoring tools for evaluating features of neurocardial fitness have been developed. The goal of this study was to demonstrate heart rate and heart rate variability analysis for the first time during Tai Chi and jogging. Continuous electrocardiographic monitoring over a period of 75 minutes was performed simultaneously in two healthy volunteers using the same type of equipment (medilog AR12 systems). Two healthy persons (both male, 49 years and 52 years, respectively), both hobby sportsmen, were monitored continuously during two resting periods before and after active sport and also during Tai Chi and jogging, respectively. Data acquisition was performed without any technical problems in both subjects. Poincaré plots of sequential R-R intervals (beat to beat variability) show two ellipses of different shape and magnitude. During resting periods blood pressure effects can be clearly seen in one subject (jogging). The same effects, however reduced, are obvious in the other volunteer during Tai Chi. The present investigations during Tai Chi and jogging highlight the potential value of heart rate and heart rate variability monitoring even under difficult conditions. The innovative kind of analysis helps to show how well the human body reacts to sport, stress and recovery.

  20. Children's Heart Rate Reactivity Responses to Three School Tasks.

    ERIC Educational Resources Information Center

    Sharpley, Christopher F.; And Others

    1989-01-01

    Investigated effects of 3 routine classroom arithmetic and reading tasks upon the heart rate reactivity of 30 fifth grade children. Results indicated that some children showed large increases in heart rates during the three tasks, and that these children should be considered at risk for coronary heart disease. (Author/TE)

  1. Fighter pilots' heart rate, heart rate variation and performance during an instrument flight rules proficiency test.

    PubMed

    Mansikka, Heikki; Virtanen, Kai; Harris, Don; Simola, Petteri

    2016-09-01

    Increased task demand will increase the pilot mental workload (PMWL). When PMWL is increased, mental overload may occur resulting in degraded performance. During pilots' instrument flight rules (IFR) proficiency test, PMWL is typically not measured. Therefore, little is known about workload during the proficiency test and pilots' potential to cope with higher task demands than those experienced during the test. In this study, fighter pilots' performance and PMWL was measured during a real IFR proficiency test in an F/A-18 simulator. PMWL was measured using heart rate (HR) and heart rate variation (HRV). Performance was rated using Finnish Air Force's official rating scales. Results indicated that HR and HRV differentiate varying task demands in situations where variations in performance are insignificant. It was concluded that during a proficiency test, PMWL should be measured together with the task performance measurement. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Relation of heart rate recovery to heart rate variability in persons with paraplegia.

    PubMed

    Jae, Sae Young; Heffernan, Kevin S; Lee, Miyoung; Fernhall, Bo

    2011-04-01

    Heart rate recovery (HRR) after treadmill exercise testing is an index of cardiac autonomic activity in non-disabled persons, but it is unknown if this is also the case in individuals with spinal cord injury (SCI). We investigated the relationship between HRR after maximal arm exercise testing and resting autonomic activity in persons with paraplegia. A total of 17 (male n = 9, female n = 8) active individuals with paraplegia (injury below T6) were included in the study. Frequency domain analyses of resting heart rate variability were obtained and participants completed a maximal arm exercise test. HRR was calculated as the difference between peak heart rate during the test and heart rate 1 min (HRR1) and 2 (HRR2) min after cessation of exercise. HRR 1 and HRR 2 were statistically significantly correlated with high-frequency (HF) power (r = 0.46, p < 0.05 and r = 0.47, p < 0.05) and the LF/HF ratio (r = -0.49, p < 0.05 and r = -0.50, p < 0.05). After adjusting for age, peak heart rate and peak oxygen uptake, HRR 2 was still significantly associated with HF power (r = 0.50, p < 0.05) and the LF/HF ratio (r = -0.58, p < 0.05). These findings indicate that HRR after maximal arm exercise testing is associated with resting cardiac autonomic activity in persons with paraplegia. This would suggest that HRR after maximal arm exercise testing can be used as an index of autonomic function in this population.

  3. Trans Fat Bans May Have Cut Heart Attack, Stroke Rate

    MedlinePlus

    ... 164605.html Trans Fat Bans May Have Cut Heart Attack, Stroke Rate Pending FDA regulations should remove nearly ... Could the contents of your cupcake affect your heart attack risk? It seems so, according to a new ...

  4. Quantitative analysis of heart rate variability

    NASA Astrophysics Data System (ADS)

    Kurths, J.; Voss, A.; Saparin, P.; Witt, A.; Kleiner, H. J.; Wessel, N.

    1995-03-01

    In the modern industrialized countries every year several hundred thousands of people die due to sudden cardiac death. The individual risk for this sudden cardiac death cannot be defined precisely by common available, noninvasive diagnostic tools like Holter monitoring, highly amplified ECG and traditional linear analysis of heart rate variability (HRV). Therefore, we apply some rather unconventional methods of nonlinear dynamics to analyze the HRV. Especially, some complexity measures that are based on symbolic dynamics as well as a new measure, the renormalized entropy, detect some abnormalities in the HRV of several patients who have been classified in the low risk group by traditional methods. A combination of these complexity measures with the parameters in the frequency domain seems to be a promising way to get a more precise definition of the individual risk. These findings have to be validated by a representative number of patients.

  5. Genetic influences on heart rate variability.

    PubMed

    Golosheykin, Simon; Grant, Julia D; Novak, Olga V; Heath, Andrew C; Anokhin, Andrey P

    2017-05-01

    Heart rate variability (HRV) is the variation of cardiac inter-beat intervals over time resulting largely from the interplay between the sympathetic and parasympathetic branches of the autonomic nervous system. Individual differences in HRV are associated with emotion regulation, personality, psychopathology, cardiovascular health, and mortality. Previous studies have shown significant heritability of HRV measures. Here we extend genetic research on HRV by investigating sex differences in genetic underpinnings of HRV, the degree of genetic overlap among different measurement domains of HRV, and phenotypic and genetic relationships between HRV and the resting heart rate (HR). We performed electrocardiogram (ECG) recordings in a large population-representative sample of young adult twins (n=1060 individuals) and computed HRV measures from three domains: time, frequency, and nonlinear dynamics. Genetic and environmental influences on HRV measures were estimated using linear structural equation modeling of twin data. The results showed that variability of HRV and HR measures can be accounted for by additive genetic and non-shared environmental influences (AE model), with no evidence for significant shared environmental effects. Heritability estimates ranged from 47 to 64%, with little difference across HRV measurement domains. Genetic influences did not differ between genders for most variables except the square root of the mean squared differences between successive R-R intervals (RMSSD, higher heritability in males) and the ratio of low to high frequency power (LF/HF, distinct genetic factors operating in males and females). The results indicate high phenotypic and especially genetic correlations between HRV measures from different domains, suggesting that >90% of genetic influences are shared across measures. Finally, about 40% of genetic variance in HRV was shared with HR. In conclusion, both HR and HRV measures are highly heritable traits in the general population

  6. Heart Rate Variability Measurements During Exercise Test May Improve the Diagnosis of Ischemic Heart Disease

    DTIC Science & Technology

    2001-10-25

    Abstract – In this work we have analyzed changes in the heart rate variability (HRV) during exercise test comparing them with the ST deviation...exactness up to 84%. The very high frequency (0.4 to 1 Hz) at the stress peak has shown to have diagnostic value. Adding the age and the maximum heart ...Keywords – Heart rate variability, exercise test, ischemia. I. INTRODUCTION Heart rate variability (HRV) measurements during exercise test have not

  7. Biophysical characterization of the underappreciated and important relationship between heart rate variability and heart rate.

    PubMed

    Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

    2014-12-01

    Heart rate (HR) variability (HRV; beat-to-beat changes in the R-wave to R-wave interval) has attracted considerable attention during the past 30+ years (PubMed currently lists >17 000 publications). Clinically, a decrease in HRV is correlated to higher morbidity and mortality in diverse conditions, from heart disease to fetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated HRV parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart, and single sinoatrial nodal cell) in diverse species, combining this with data from previously published articles. We show that regardless of conditions, there is a universal exponential decay-like relationship between HRV and HR. Using 2 biophysical models, we develop a theory for this and confirm that HRV is primarily dependent on HR and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in HRV and altered morbidity and mortality is substantially attributable to the concurrent change in HR. This calls for re-evaluation of the findings from many articles that have not adjusted properly or at all for HR differences when comparing HRV in multiple circumstances. © 2014 American Heart Association, Inc.

  8. Procedural Pain Heart Rate Responses in Massaged Preterm Infants

    PubMed Central

    Diego, Miguel A.; Field, Tiffany; Hernandez-Reif, Maria

    2009-01-01

    Heart rate (HR) responses to the removal of a monitoring lead were assessed in 56 preterm infants who received moderate pressure, light pressure or no massage therapy. The infants who received moderate pressure massage therapy exhibited lower increases in HR suggesting an attenuated pain response. The heart rate of infants who received moderate pressure massage also returned to baseline faster than the heart rate of the other two groups, suggesting a faster recovery rate. PMID:19185352

  9. Heart rate reduction in cardiovascular disease and therapy.

    PubMed

    Reil, Jan-Christian; Custodis, Florian; Swedberg, Karl; Komajda, Michel; Borer, Jeffrey S; Ford, Ian; Tavazzi, Luigi; Laufs, Ulrich; Böhm, Michael

    2011-01-01

    Heart rate influences myocardial oxygen demand, coronary blood flow, and myocardial function. Clinical and experimental studies support an association between elevated resting heart rate and a broad range of maladaptive effects on the function and structure of the cardiovascular system. Heart rate has been shown to be an important predictor of mortality in cardiovascular disorders such as coronary artery disease, myocardial infarction, and chronic heart failure. This review summarizes the specific influence of heart rate on vascular morphology and function as well as on myocardial lesions leading from early impact on vascular homeostasis to myocardial hemodynamics in chronic heart failure. Heart rate can be easily determined during physical examination of the patient and therefore allows a simple hint on prognosis and efficiency of therapy.

  10. Ordinal pattern statistics for the assessment of heart rate variability

    NASA Astrophysics Data System (ADS)

    Graff, G.; Graff, B.; Kaczkowska, A.; Makowiec, D.; Amigó, J. M.; Piskorski, J.; Narkiewicz, K.; Guzik, P.

    2013-06-01

    The recognition of all main features of a healthy heart rhythm (the so-called sinus rhythm) is still one of the biggest challenges in contemporary cardiology. Recently the interesting physiological phenomenon of heart rate asymmetry has been observed. This phenomenon is related to unbalanced contributions of heart rate decelerations and accelerations to heart rate variability. In this paper we apply methods based on the concept of ordinal pattern to the analysis of electrocardiograms (inter-peak intervals) of healthy subjects in the supine position. This way we observe new regularities of the heart rhythm related to the distribution of ordinal patterns of lengths 3 and 4.

  11. Inverse Correlation between Heart Rate Variability and Heart Rate Demonstrated by Linear and Nonlinear Analysis

    PubMed Central

    Zhang, Henggui; Aziz, Wajid; Monfredi, Oliver; Abbas, Syed Ali; Shah, Saeed Arif; Kazmi, Syeda Sobia Hassan; Butt, Wasi Haider

    2016-01-01

    The dynamical fluctuations in the rhythms of biological systems provide valuable information about the underlying functioning of these systems. During the past few decades analysis of cardiac function based on the heart rate variability (HRV; variation in R wave to R wave intervals) has attracted great attention, resulting in more than 17000-publications (PubMed list). However, it is still controversial about the underling mechanisms of HRV. In this study, we performed both linear (time domain and frequency domain) and nonlinear analysis of HRV data acquired from humans and animals to identify the relationship between HRV and heart rate (HR). The HRV data consists of the following groups: (a) human normal sinus rhythm (n = 72); (b) human congestive heart failure (n = 44); (c) rabbit sinoatrial node cells (SANC; n = 67); (d) conscious rat (n = 11). In both human and animal data at variant pathological conditions, both linear and nonlinear analysis techniques showed an inverse correlation between HRV and HR, supporting the concept that HRV is dependent on HR, and therefore, HRV cannot be used in an ordinary manner to analyse autonomic nerve activity of a heart. PMID:27336907

  12. The relationship between physical activity and heart rate variability in orthotopic heart transplant recipients.

    PubMed

    Lai, Fu-Chih; Chang, Wen-Lin; Jeng, Chii

    2012-11-01

    To investigate the relationship between physical activity and heart rate variability in orthotopic heart transplant recipients, to compare the difference in heart rate variability between patients one year after orthotopic heart transplant and healthy adults matched to the heart transplant recipients in terms of age, gender and physical activity levels. Although physical activity affects the heart rate variability in patients with heart disease, there is a paucity of literature discussing the correlation between physical activity and heart rate variability among heart transplant recipients. This was a descriptive and cross-sectional study. A total of 120 eligible subjects were divided into the orthotopic heart transplant recipient group (n = 60) and the healthy adult group (n = 60). The Seven-day Physical Activity Recall questionnaire was used to record the subjects' amount of physical activity per week. Heart rate variety parameters were determined by separate frequency domain components. Results indicated heart transplant recipients' heart rate variety was significantly lower than that of healthy adults in terms of mean, sdr, total power (ms(2)), low frequency (ms(2)), low frequency (nu), high frequency (ms(2)) and low frequency/high frequency. Heart transplant recipients' heart rate variety including total power (ms(2)), low frequency (ms(2)) and high frequency (ms(2)) was 18·2, 2 and 7·2% of healthy controls, respectively; the amount of absolutely and relatively moderate physical activity was positively related to high frequency (ms(2)) and high frequency (nu), but was negatively related to low frequency/high frequency. High frequency (nu) increases while the total amount of weekly physical activity increases. Results confirmed that the more the moderate physical activity performed, the better the patient's heart rate variability. We suggest that clinical care providers have to encourage heart transplant recipients to engage in moderate physical activity.

  13. Improving Video Based Heart Rate Monitoring.

    PubMed

    Lin, Jian; Rozado, David; Duenser, Andreas

    2015-01-01

    Non-contact measurements of cardiac pulse can provide robust measurement of heart rate (HR) without the annoyance of attaching electrodes to the body. In this paper we explore a novel and reliable method to carry out video-based HR estimation and propose various performance improvement over existing approaches. The investigated method uses Independent Component Analysis (ICA) to detect the underlying HR signal from a mixed source signal present in the RGB channels of the image. The original ICA algorithm was implemented and several modifications were explored in order to determine which one could be optimal for accurate HR estimation. Using statistical analysis, we compared the cardiac pulse rate estimation from the different methods under comparison on the extracted videos to a commercially available oximeter. We found that some of these methods are quite effective and efficient in terms of improving accuracy and latency of the system. We have made the code of our algorithms openly available to the scientific community so that other researchers can explore how to integrate video-based HR monitoring in novel health technology applications. We conclude by noting that recent advances in video-based HR monitoring permit computers to be aware of a user's psychophysiological status in real time.

  14. Heart rate variability index in trauma patients.

    PubMed

    Proctor, Kenneth G; Atapattu, Suresh A; Duncan, Robert C

    2007-07-01

    Heart rate variability (HRV) changes often reflect autonomic dysfunction with high sensitivity, but the specificity is also low. There are several different methods for measuring HRV, but interpretation is often complex, and the units are not interchangeable. For these reasons, HRV monitoring is not routinely used in many clinical situations. We hypothesized that the specificity of HRV as a screening tool for trauma patients could be improved by controlling some of the confounding influences using multiple logistic regression. A prospective observational trial with waiver of consent was performed in 243 healthy student volunteers and 257 trauma patients, in the resuscitation bay and intensive care units of a Level I trauma center, who received computed axial tomography (CT) scans of the head as part of the initial work up. Electrocardiogram results were recorded for 5 minutes. HRV was defined by SD of normal R-R intervals (SDNN5) and by root mean square of successive differences of R-R intervals (RMSSD5). A head CT scan was considered positive (+) if there were abnormalities in the parenchyma (diffuse axonal injury or contusion), vasculature (intraparenchymal, subdural, or epidural hemorrhage), and/or structural or bony components (fractures of the face or cranium). In volunteers, SDNN5 was 73 +/- 15 (M +/- SD) milliseconds, compared with 42 +/- 22, 31 +/- 19, 28 +/- 17, and 12 +/- 8 milliseconds in, CT(-) patients with no sedation (n = 82), CT(-) with sedation (n = 60), CT(+) with no sedation (n = 55), and CT(+) with sedation (n = 60), respectively. The differences between trauma, sedation, and CT categories were significant (all p < 0.001). RMSSD5 differences were similar and also highly significant (all p < 0.001). For both SDNN5 and RMSSD5, in each category, there was wide overlap in the range of values, and strong inverse correlations with heart rate (all p < 0.001). Using multiple logistic regression in a subset with no missing data (n = 194), an index was

  15. Heart rate variability and blood pressure during dynamic and static exercise at similar heart rate levels.

    PubMed

    Weippert, Matthias; Behrens, Kristin; Rieger, Annika; Stoll, Regina; Kreuzfeld, Steffi

    2013-01-01

    Aim was to elucidate autonomic responses to dynamic and static (isometric) exercise of the lower limbs eliciting the same moderate heart rate (HR) response. 23 males performed two kinds of voluntary exercise in a supine position at similar heart rates: static exercise (SE) of the lower limbs (static leg press) and dynamic exercise (DE) of the lower limbs (cycling). Subjective effort, systolic (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), rate pressure product (RPP) and the time between consecutive heart beats (RR-intervals) were measured. Time-domain (SDNN, RMSSD), frequency-domain (power in the low and high frequency band (LFP, HFP)) and geometric measures (SD1, SD2) as well as non-linear measures of regularity (approximate entropy (ApEn), sample entropy (SampEn) and correlation dimension D2) were calculated. Although HR was similar during both exercise conditions (88±10 bpm), subjective effort, SBP, DBP, MAP and RPP were significantly enhanced during SE. HRV indicators representing overall variability (SDNN, SD 2) and vagal modulated variability (RMSSD, HFP, SD 1) were increased. LFP, thought to be modulated by both autonomic branches, tended to be higher during SE. ApEn and SampEn were decreased whereas D2 was enhanced during SE. It can be concluded that autonomic control processes during SE and DE were qualitatively different despite similar heart rate levels. The differences were reflected by blood pressure and HRV indices. HRV-measures indicated a stronger vagal cardiac activity during SE, while blood pressure response indicated a stronger sympathetic efferent activity to the vessels. The elevated vagal cardiac activity during SE might be a response mechanism, compensating a possible co-activation of sympathetic cardiac efferents, as HR and LF/HF was similar and LFP tended to be higher. However, this conclusion must be drawn cautiously as there is no HRV-marker reflecting "pure" sympathetic cardiac activity.

  16. Interaction of a commercial heart rate monitor with implanted pacemakers.

    PubMed

    Joglar, J A; Hamdan, M H; Welch, P J; Page, R L

    1999-03-01

    Dry-electrode heart rate monitors allow display of heart rate by transmitting a signal to the receiving device, which typically is on the wrist or exercise machine, but due to the potential for electromagnetic interference, their use has been contraindicated in patients with pacemakers. In 12 patients, we found no adverse effect on pacemaker function; in addition, the monitors generally were accurate in measuring heart rate during pacing.

  17. A Bayesian classification of heart rate variability data

    NASA Astrophysics Data System (ADS)

    Muirhead, R. J.; Puff, R. D.

    2004-05-01

    We propose a simple Bayesian method for the classification of time series signals originating from mutually exclusive sources. In particular, the method is used to address the question of whether a 24-h recording of human heart rate data is produced by a normally functioning heart or by one exhibiting symptoms of congestive heart failure. Our method correctly classifies 18 of 18 normal heart data sets, and 38 of 44 congestive failure data sets.

  18. Heart Rate, Life Expectancy and the Cardiovascular System: Therapeutic Considerations.

    PubMed

    Boudoulas, Konstantinos Dean; Borer, Jeffrey S; Boudoulas, Harisios

    2015-01-01

    It has long been known that life span is inversely related to resting heart rate in most organisms. This association between heart rate and survival has been attributed to the metabolic rate, which is greater in smaller animals and is directly associated with heart rate. Studies have shown that heart rate is related to survival in apparently healthy individuals and in patients with different underlying cardiovascular diseases. A decrease in heart rate due to therapeutic interventions may result in an increase in survival. However, there are many factors regulating heart rate, and it is quite plausible that these may independently affect life expectancy. Nonetheless, a fast heart rate itself affects the cardiovascular system in multiple ways (it increases ventricular work, myocardial oxygen consumption, endothelial stress, aortic/arterial stiffness, decreases myocardial oxygen supply, other) which, in turn, may affect survival. In this brief review, the effects of heart rate on the heart, arterial system and survival will be discussed. © 2015 S. Karger AG, Basel.

  19. Critical Scale Invariance in a Healthy Human Heart Rate

    NASA Astrophysics Data System (ADS)

    Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Sakata, Seiichiro; Hayano, Junichiro; Yamamoto, Yoshiharu

    2004-10-01

    We demonstrate the robust scale-invariance in the probability density function (PDF) of detrended healthy human heart rate increments, which is preserved not only in a quiescent condition, but also in a dynamic state where the mean level of the heart rate is dramatically changing. This scale-independent and fractal structure is markedly different from the scale-dependent PDF evolution observed in a turbulentlike, cascade heart rate model. These results strongly support the view that a healthy human heart rate is controlled to converge continually to a critical state.

  20. Accuracy of smartphone apps for heart rate measurement.

    PubMed

    Coppetti, Thomas; Brauchlin, Andreas; Müggler, Simon; Attinger-Toller, Adrian; Templin, Christian; Schönrath, Felix; Hellermann, Jens; Lüscher, Thomas F; Biaggi, Patric; Wyss, Christophe A

    2017-08-01

    Background Smartphone manufacturers offer mobile health monitoring technology to their customers, including apps using the built-in camera for heart rate assessment. This study aimed to test the diagnostic accuracy of such heart rate measuring apps in clinical practice. Methods The feasibility and accuracy of measuring heart rate was tested on four commercially available apps using both iPhone 4 and iPhone 5. 'Instant Heart Rate' (IHR) and 'Heart Fitness' (HF) work with contact photoplethysmography (contact of fingertip to built-in camera), while 'Whats My Heart Rate' (WMH) and 'Cardiio Version' (CAR) work with non-contact photoplethysmography. The measurements were compared to electrocardiogram and pulse oximetry-derived heart rate. Results Heart rate measurement using app-based photoplethysmography was performed on 108 randomly selected patients. The electrocardiogram-derived heart rate correlated well with pulse oximetry ( r = 0.92), IHR ( r = 0.83) and HF ( r = 0.96), but somewhat less with WMH ( r = 0.62) and CAR ( r = 0.60). The accuracy of app-measured heart rate as compared to electrocardiogram, reported as mean absolute error (in bpm ± standard error) was 2 ± 0.35 (pulse oximetry), 4.5 ± 1.1 (IHR), 2 ± 0.5 (HF), 7.1 ± 1.4 (WMH) and 8.1 ± 1.4 (CAR). Conclusions We found substantial performance differences between the four studied heart rate measuring apps. The two contact photoplethysmography-based apps had higher feasibility and better accuracy for heart rate measurement than the two non-contact photoplethysmography-based apps.

  1. Ivabradine: Cardioprotection By and Beyond Heart Rate Reduction.

    PubMed

    Heusch, Gerd; Kleinbongard, Petra

    2016-05-01

    Ivabradine inhibits hyperpolarization-activated cyclic nucleotide-gated channels in the sinus node, thereby reducing heart rate, and heart rate reduction improves regional myocardial blood flow and contractile function in ischemic myocardium. Accordingly, ivabradine reduces anginal symptoms in patients with stable coronary artery disease but does not improve their clinical outcome. Heart rate reduction with ivabradine in patients with symptomatic heart failure reduces symptoms, attenuates remodeling, and improves clinical outcome. In pigs and mice, ivabradine reduces infarct size from myocardial ischemia/reperfusion, even when heart rate reduction is abrogated by atrial pacing. Improved viability is also observed in isolated ventricular cardiomyocytes subjected to simulated ischemia/reperfusion. These beneficial effects are attributed to reduced reactive oxygen species formation from the mitochondria. There is also evidence for a heart rate-independent benefit from ivabradine in the vasculature of mice and humans, and in left ventricular contractile function of pigs. Finally, in mice, ivabradine also has anti-aging potential.

  2. Heart rate variability and suicidal behavior.

    PubMed

    Wilson, Scott T; Chesin, Megan; Fertuck, Eric; Keilp, John; Brodsky, Beth; Mann, J John; Sönmez, Cemile Ceren; Benjamin-Phillips, Christopher; Stanley, Barbara

    2016-06-30

    Identification of biological indicators of suicide risk is important given advantages of biomarker-based models. Decreased high frequency heart rate variability (HF HRV) may be a biomarker of suicide risk. The aim of this research was to determine whether HF HRV differs between suicide attempters and non-attempters. Using the Trier Social Stress Test (TSST), we compared HF HRV between females with and without a history of suicide attempt, all with a lifetime diagnosis of a mood disorder. To investigate a potential mechanism explaining association between HF HRV and suicide, we examined the association between self-reported anger and HF HRV. Results of an Area under the Curve (AUC) analysis showed attempters had a lower cumulative HF HRV during the TSST than non-attempters. In addition, while there was no difference in self-reported anger at baseline, the increase in anger was greater in attempters, and negatively associated with HF HRV. Results suggest that suicide attempters have a reduced capacity to regulate their response to stress, and that reduced capacity to regulate anger may be a mechanism through which decreased HF HRV can lead to an increase in suicide risk. Our results have implications for the prevention of suicidal behavior in at-risk populations.

  3. Heart rate patterns in trisomic fetuses.

    PubMed

    Kariniemi, V; Aula, P

    1982-01-01

    A survey of the clinical records of fifteen fetuses with trisomy 21, six fetuses with trisomy 18, and two fetuses with trisomy 13 was made in order to find out typical patterns of fetal heart rate (FHR) possibly associated with these conditions. Antepartal FHR patterns of 55 normal pregnancies and intrapartal FHR patterns of 14 normal labors were used as a control material. Trisomic fetuses showed significantly fewer FHR accelerations than did the controls. Fetuses with trisomy 18 and 13 had more antepartal decelerations than fetuses with trisomy 21. Trisomic fetuses also showed more intrapartal late decelerations and epochs of silent FHR pattern than did the controls. The abnormal FHR patterns of the trisomic fetuses thus were similar to those in placental insufficiency. Cesarean section was performed for both fetuses with trisomy 13, for five of the six fetuses with trisomy 18 and for nine of fifteen fetuses with trisomy 21. In eleven of sixteen cesarean sections the main indication was abnormal cardiotocogram. Fetal karyotyping from an amniotic fluid sample should perhaps be considered when decelerations and silent patterns of FHR in a growth-retarded, late second or early third trimester fetus are seen. In most cases, however, the decision for optimal management o labor must be based on FHR patterns solely.

  4. Early warnings of heart rate deterioration.

    PubMed

    Almeida, Vania G; Nabney, Ian T

    2016-08-01

    Hospitals can experience difficulty in detecting and responding to early signs of patient deterioration leading to late intensive care referrals, excess mortality and morbidity, and increased hospital costs. Our study aims to explore potential indicators of physiological deterioration by the analysis of vital-signs. The dataset used comprises heart rate (HR) measurements from MIMIC II waveform database, taken from six patients admitted to the Intensive Care Unit (ICU) and diagnosed with severe sepsis. Different indicators were considered: 1) generic early warning indicators used in ecosystems analysis (autocorrelation at-1-lag (ACF1), standard deviation (SD), skewness, kurtosis and heteroskedasticity) and 2) entropy analysis (kernel entropy and multi scale entropy). Our preliminary findings suggest that when a critical transition is approaching, the equilibrium state changes what is visible in the ACF1 and SD values, but also by the analysis of the entropy. Entropy allows to characterize the complexity of the time series during the hospital stay and can be used as an indicator of regime shifts in a patient's condition. One of the main problems is its dependency of the scale used. Our results demonstrate that different entropy scales should be used depending of the level of entropy verified.

  5. Investigation of determinism in heart rate variability

    NASA Astrophysics Data System (ADS)

    Gomes, M. E. D.; Souza, A. V. P.; Guimarães, H. N.; Aguirre, L. A.

    2000-06-01

    The article searches for the possible presence of determinism in heart rate variability (HRV) signals by using a new approach based on NARMA (nonlinear autoregressive moving average) modeling and free-run prediction. Thirty-three 256-point HRV time series obtained from Wistar rats submitted to different autonomic blockade protocols are considered, and a collection of surrogate data sets are generated from each one of them. These surrogate sequences are assumed to be nondeterministic and therefore they may not be predictable. The original HRV time series and related surrogates are submitted to NARMA modeling and prediction. Special attention has been paid to the problem of stationarity. The results consistently show that the surrogate data sets cannot be predicted better than the trivial predictor—the mean—while most of the HRV control sequences are predictable to a certain degree. This suggests that the normal HRV signals have a deterministic signature. The HRV time series derived from the autonomic blockade segments of the experimental protocols do not show the same predictability performance, albeit the physiological interpretation is not obvious. These results have important implications to the methodology of HRV analysis, indicating that techniques from nonlinear dynamics and deterministic chaos may be applied to elicit more information about the autonomic modulation of the cardiovascular activity.

  6. Heart rate variability reproducibility during exercise.

    PubMed

    McNarry, Melitta A; Lewis, Michael J

    2012-07-01

    The use of heart rate variability (HRV) parameters during exercise is not supported by appropriate reliability studies. In 80 healthy adults, ECG was recorded during three 6 min bouts of exercise, separated by 6 min of unloaded cycling. Two bouts were at a moderate intensity while the final bout was at a heavy exercise intensity. This protocol was repeated under the same conditions on three occasions, with a controlled start time (pre-determined at the first visit). Standard time and frequency domain indices of HRV were derived. Reliability was assessed by Bland–Altman plots, 95% limits of agreement and intraclass correlation coefficients (ICC). The sample size required to detect a mean difference ≥30% of the between-subject standard deviation was also estimated. There was no systematic change between days. All HRV parameters demonstrated a high degree of reproducibility during baseline (ICC range: 0.58–0.75), moderate (ICC: 0.58–0.85) and heavy intensity exercise (ICC range: 0.40–0.76). The reproducibility was slightly diminished during heavy intensity exercise relative to both unloaded baseline cycling and moderate exercise. This study indicates that HRV parameters can be reliably determined during exercise, and it underlines the importance of standardizing exercise intensity with regard to fitness levels if HRV is to be reliably determined.

  7. Drowsiness detection using heart rate variability.

    PubMed

    Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel

    2016-06-01

    It is estimated that 10-30 % of road fatalities are related to drowsy driving. Driver's drowsiness detection based on biological and vehicle signals is being studied in preventive car safety. Autonomous nervous system activity, which can be measured noninvasively from the heart rate variability (HRV) signal obtained from surface electrocardiogram, presents alterations during stress, extreme fatigue and drowsiness episodes. We hypothesized that these alterations manifest on HRV and thus could be used to detect driver's drowsiness. We analyzed three driving databases in which drivers presented different sleep-deprivation levels, and in which each driving minute was annotated as drowsy or awake. We developed two different drowsiness detectors based on HRV. While the drowsiness episodes detector assessed each minute of driving as "awake" or "drowsy" with seven HRV derived features (positive predictive value 0.96, sensitivity 0.59, specificity 0.98 on 3475 min of driving), the sleep-deprivation detector discerned if a driver was suitable for driving or not, at driving onset, as function of his sleep-deprivation state. Sleep-deprivation state was estimated from the first three minutes of driving using only one HRV feature (positive predictive value 0.80, sensitivity 0.62, specificity 0.88 on 30 drivers). Incorporating drowsiness assessment based on HRV signal may add significant improvements to existing car safety systems.

  8. Controlling the emotional heart: heart rate biofeedback improves cardiac control during emotional reactions.

    PubMed

    Peira, Nathalie; Fredrikson, Mats; Pourtois, Gilles

    2014-03-01

    When regulating negative emotional reactions, one goal is to reduce physiological reactions. However, not all regulation strategies succeed in doing that. We tested whether heart rate biofeedback helped participants reduce physiological reactions in response to negative and neutral pictures. When viewing neutral pictures, participants could regulate their heart rate whether the heart rate feedback was real or not. In contrast, when viewing negative pictures, participants could regulate heart rate only when feedback was real. Ratings of task success paralleled heart rate. Participants' general level of anxiety, emotion awareness, or cognitive emotion regulation strategies did not influence the results. Our findings show that accurate online heart rate biofeedback provides an efficient way to down-regulate autonomic physiological reactions when encountering negative stimuli.

  9. Sleep problems and heart rate variability over the working day.

    PubMed

    Jackowska, Marta; Dockray, Samantha; Endrighi, Romano; Hendrickx, Hilde; Steptoe, Andrew

    2012-08-01

    The purpose of this study was to discover whether greater sleep problems are associated with reduced heart rate variability during working hours and at night, and to determine whether this association is in part mediated by experienced affective states. This study involved 199 working women with a mean age of 33.8years. Sleep problems were assessed with the Jenkins Sleep Problems Scale, and the Day Reconstruction Method was used to measure positive affect and stress on the evening before and during the working day. Heart rate variability was indexed by the mean square root of the successive standard difference in heart period. Disturbed sleep was inversely related to heart rate variability during the working day (P=0.022), independently of demographic and behavioural confounders. Additional adjustment for positive affect and stress did not lead to further reductions in the association between sleep problems and reduced heart rate variability over the work day. Sleep problems were not predictive of reduced night-time heart rate variability. This report extends the findings from experimental studies and clinical samples, and suggests that disturbed sleep might impair heart rate variability in real life settings, in particular during working hours. Reduced heart rate variability might be a potential pathway linking sleep problems with cardiovascular disease. Based on the current data there was little evidence that the inverse associations between sleep problems and heart rate variability were mediated by experienced affective states.

  10. Aerobic exercise during pregnancy influences fetal cardiac autonomic control of heart rate and heart rate variability.

    PubMed

    May, Linda E; Glaros, Alan; Yeh, Hung-Wen; Clapp, James F; Gustafson, Kathleen M

    2010-04-01

    Previous studies using ultrasound technology showed that fetal heart rate (HR) may be responsive to maternal aerobic exercise. Although it is recognized that cardiac autonomic control may be influenced by the intrauterine environment, little is known about how maternal exercise affects fetal heart development. This study tested the hypothesis that regular maternal exercise throughout gestation influences fetal cardiac autonomic control of HR and heart rate variability (HRV) when compared to fetuses of non-exercising women. Magnetocardiograms (MCGs) were recorded using a dedicated fetal biomagnetometer at 28, 32 and 36 weeks gestational age (GA) from 26 regularly exercising (>30 min of aerobic exercise, 3x per week) and 35 healthy, non-exercising pregnant women. Fetal MCG was isolated and normal R-peaks were marked to derive fetal HR and HRV in the time and frequency domains. We applied a mixed-effects model to investigate the effects of exercise, GA and fetal activity state. At 36 weeks GA, during the active fetal state, fetal HR was significantly lower in the exercise group (p=<0.0006). Post-hoc comparisons showed significantly increased HRV in the exercise group during the active fetal state at 36 weeks GA for both time and frequency domain measures. These results indicate that regular maternal exercise throughout gestation results in significantly lower fetal HR and increased HRV. 2010 Elsevier Ltd. All rights reserved.

  11. Long‐term Cardiovascular Risks Associated With an Elevated Heart Rate: The Framingham Heart Study

    PubMed Central

    Ho, Jennifer E.; Larson, Martin G.; Ghorbani, Anahita; Cheng, Susan; Coglianese, Erin E.; Vasan, Ramachandran S.; Wang, Thomas J.

    2014-01-01

    Background Higher heart rate has been associated with an adverse prognosis, but most prior studies focused on individuals with known cardiovascular disease or examined a limited number of outcomes. We sought to examine the association of baseline heart rate with both fatal and nonfatal outcomes during 2 decades of follow‐up. Methods and Results Our study included 4058 Framingham Heart Study participants (mean age 55 years, 56% women). Cox models were performed with multivariable adjustment for clinical risk factors and physical activity. A total of 708 participants developed incident cardiovascular disease (303 heart failure, 343 coronary heart disease, and 216 stroke events), 48 received a permanent pacemaker, and 1186 died. Baseline heart rate was associated with incident cardiovascular disease (hazard ratio [HR] 1.15 per 1 SD [11 bpm] increase in heart rate, 95% CI 1.07 to 1.24, P=0.0002), particularly heart failure (HR 1.32, 95% CI 1.18 to 1.48, P<0.0001). Higher heart rate was also associated with higher all‐cause (HR 1.17, 95% CI 1.11 to 1.24, P<0.0001) and cardiovascular mortality (HR 1.18, 95% CI 1.04 to 1.33, P=0.01). Spline analyses did not suggest a lower threshold beyond which the benefit of a lower heart rate abated or increased. In contrast, individuals with a higher heart rate had a lower risk of requiring permanent pacemaker placement (HR 0.55, 95% CI 0.38 to 0.79, P=0.001). Conclusions Individuals with a higher heart rate are at elevated long‐term risk for cardiovascular events, in particular, heart failure, and all‐cause death. On the other hand, a higher heart rate is associated with a lower risk of future permanent pacemaker implantation. PMID:24811610

  12. Reduced intrinsic heart rate is associated with reduced arrhythmic susceptibility in guinea-pig heart.

    PubMed

    Osadchii, Oleg E

    2014-12-01

    In the clinical setting, patients with slower resting heart rate are less prone to cardiovascular death compared with those with elevated heart rate. However, electrophysiological adaptations associated with reduced cardiac rhythm have not been thoroughly explored. In this study, relationships between intrinsic heart rate and arrhythmic susceptibility were examined by assessments of action potential duration (APD) rate adaptation and inducibility of repolarization alternans in sinoatrial node (SAN)-driven and atrioventricular (AV)-blocked guinea-pig hearts perfused with Langendorff apparatus. Electrocardiograms, epicardial monophasic action potentials, and effective refractory periods (ERP) were assessed in normokalemic and hypokalemic conditions. Slower basal heart rate in AV-blocked hearts was associated with prolonged ventricular repolarization during spontaneous beating, and with attenuated APD shortening at increased cardiac activation rates during dynamic pacing, when compared with SAN-driven hearts. During hypokalemic perfusion, the inducibility of repolarization alternans and tachyarrhythmia by rapid pacing was found to be lower in AV-blocked hearts. This difference was ascribed to prolonged ERP in the setting of reduced basal heart rate, which prevented ventricular capture at critically short pacing intervals required to induce arrhythmia. Reduced basal heart rate is associated with electrophysiological changes that prevent electrical instability upon an abrupt cardiac acceleration.

  13. Associations of resting heart rate with endothelium-dependent vasodilation and shear rate.

    PubMed

    Laosiripisan, Jitanan; Parkhurst, Kristin L; Tanaka, Hirofumi

    2017-01-01

    Heart rate is an independent risk factor for cardiovascular disease and a hemodynamic factor that can modulate blood flow as it affects the frequency of shear stimuli acting on the arterial wall. However, the association between heart rate and endothelium-dependent vasodilation remains highly controversial. We determined the association between heart rate at rest and endothelium-dependent vasodilation in 98 apparently healthy adults (18-63 years). The mild and positive association between heart rate and flow-mediated dilation (FMD) was no longer significant when age and sex or baseline diameter were controlled for. The path analyses revealed that heart rate was not directly related to FMD but the association was indirectly mediated by shear rate, which was confirmed by a bias-corrected bootstrap 95% CIs (0.0157-0.1056). We concluded that even though heart rate and endothelium-dependent vasodilation were associated with shear rate, there was no independent relation between heart rate and FMD.

  14. Primary prevention of ischaemic heart disease: WHO coordinated cooperative trial

    PubMed Central

    1979-01-01

    Elevated serum cholesterol concentrations are known to be predictive of ischaemic heart disease. It remained to be proven, however, whether reduction of clinically manifest ischaemic heart disease could be achieved by the lowering of elevated serum-cholesterol levels. In order to create a clear and simple unifactorial study design, a lipid-lowering substance (clofibrate) was administered to this effect in a double-blind trial to middle-aged male volunteers whose serum cholesterol levels were within the upper third of the distribution in their respective populations (Budapest, Edinburgh, Prague). After an average of 5.3 years of observation, and with a reduction of some 9% of the initial serum cholesterol levels, the incidence of ischaemic heart disease was reduced by 20% in the intervention group as compared with the placebo group, thus demonstrating the preventive value of lowering this plasma lipid. There was, however, a significant increase in total mortality and in non-cardiovascular mortality in the clofibrate group, precluding the community-wide use of this drug for reduction of serum cholesterol. The explanation of this is not clear, but possible mechanisms are discussed. PMID:317255

  15. Heart rate, health, and hurtful behavior.

    PubMed

    Jennings, J Richard; Pardini, Dustin A; Matthews, Karen A

    2017-03-01

    Hostility is a risk factor for cardiovascular events. When challenged, individuals high on hostility exhibit a hyperreactive psychophysiological response to stressors, thereby increasing risk for developing cardiovascular disease. However, low resting heart rate (HR) is associated with physical aggression and hostility in children, adolescents, and adults. Based on a community sample of 296 men (mean age = 32.0), we (a) address whether aggression/hostility relates to physical health through relationships with cardiovascular levels at rest and in response to stressors, and (b) determine how relations between aggression and health are altered by including psychophysiological indices in statistical models. The Cook-Medley cynical/hostile attitudes and the Buss-Perry physical aggression and hostility measures assessed aggression. Health was assessed as systolic blood pressure (SBP), report of medical conditions, and a metabolic composite. Reactivity to stressors was assessed with HR, SBP, and diastolic blood pressure. Aggression was negatively related to both resting HR and reactivity. High resting HR and reactivity were, however, positively related to poor health. Thus, the relationship between aggression and HR and reactivity suppressed an overall relationship between high aggression/hostility and poor health. In the presence of covariates for socioeconomic status, race, health behaviors, and medications, the relationship between aggression and health was significantly strengthened when HR level and reactivity were included in models. In sum, at early midlife, low HR among aggressive and hostile individuals is related to less health risk. Aggression and hostility have a deleterious influence on health, but primarily among individuals with higher HR and possibly greater cardiovascular reactivity.

  16. [Population characteristics and impact on heart rate variability, heart rate and blood pressure of passive smoking].

    PubMed

    Zhao, Jing; He, Fei; Hu, Da-yi; Ding, Rong-jing; Yu, Xiao-jun; Wang, Long; Zhang, Ping; Li, Xue-bin; Guo, Ji-hong; Liu, Wen-ling; Li, Cui-lan; Li, Lei; Gao, Chuan-yu; Zhao, Luo-sha; Chu, Ying-jie; Huang, Zhen-wen; Wei, Jing-han; Hua, Shao-hua; Liu, Rui-yun; Zhuang, Xiao-feng

    2013-05-01

    To investigate the basic characteristics of passive smoking population, and the impact of passive smoking on heart rate variability, heart rate and blood pressure. Eighty-six passive smokers [mean age: (52.4 ± 7.6) years] were recruited from patients and their relatives who visited cardiovascular outpatient department and excluded structural heart disease between June 2010 and June 2012, 80 normal subjects who were not exposed to smoking served as controls. Questionnaire survey, 24 hours ambulatory electrocardiogram examination and blood pressure measurement were performed in all recruited subjects. (1) Non-marriage rate [18.60% (16/86) vs. 3.75% (3/80), P < 0.01] was significantly higher while education level were significantly lower in passive smoking group than in control group. Passive smokers were more likely service industry workers [29.07% (25/86) vs. 15.00% (12/80), P < 0.05] and had longer daily working time [(7.56 ± 1.24) h vs. (6.02 ± 0.96) h, P < 0.01], and were less likely to be professional technology industry employers [20.93% (18/86) vs. 36.25% (29/80), P < 0.05] and managers [13.95% (12/86) vs. 38.75% (31/80), P < 0.01] compared to controls. The main place of passive smoking was workplace (67.44%, 58/86), entertainment venues (63.95%,55/86), restaurants (48.84%, 42/86). (2) Standard of the normal sinus RR intervals (SDNN), the normal consecutive sinus RR interval difference between the root-mean-square (rMSSD) and adjacent the difference between the RR interval>50 ms the number of share the percentage (PNN50) were significantly lower in passive smoking group than in the control group (all P < 0.05). Every 5 min average of the standard deviation of sinus RR cycle (SDNN index) and 24 h every 5 min sinus RR interval mean standard deviation (SDANN) were similar between the 2 groups (all P > 0.05). Ultra-low-frequency power (VLF), low frequency power (LF), high frequency power (HF) and LF/HF were significantly lower in passive smoking group than in

  17. Effect of Age and Other Factors on Maximal Heart Rate.

    ERIC Educational Resources Information Center

    Londeree, Ben R.; Moeschberger, Melvin L.

    1982-01-01

    To reduce confusion regarding reported effects of age on maximal exercise heart rate, a comprehensive review of the relevant English literature was conducted. Data on maximal heart rate after exercising with a bicycle, a treadmill, and after swimming were analyzed with regard to physical fitness and to age, sex, and racial differences. (Authors/PP)

  18. Using Target Heart-Rate Zones in Your Class

    ERIC Educational Resources Information Center

    Gilbert, Jennie A.

    2005-01-01

    Should teachers teach the calculation of target heart rate to students? And when is it appropriate to engage students in the attainment of these heart rates during physical education class activities? The answers to these questions are not easy. One might be tempted to state a simple yes or no and to identify a specific age to begin using training…

  19. Modeling heart rate variability in healthy humans: a turbulence analogy.

    PubMed

    Lin, D C; Hughson, R L

    2001-02-19

    Many complex systems share similar statistical characteristics. In this Letter, a turbulence analogy is proposed for the long-term heart rate variability of healthy humans. Based on such an analogy, the equivalence of an inertial range is found and a cascade model, which captures the statistical properties of the heart rate data, is given.

  20. Using Target Heart-Rate Zones in Your Class

    ERIC Educational Resources Information Center

    Gilbert, Jennie A.

    2005-01-01

    Should teachers teach the calculation of target heart rate to students? And when is it appropriate to engage students in the attainment of these heart rates during physical education class activities? The answers to these questions are not easy. One might be tempted to state a simple yes or no and to identify a specific age to begin using training…

  1. Modeling Heart Rate Variability in Healthy Humans: A Turbulence Analogy

    NASA Astrophysics Data System (ADS)

    Lin, D. C.; Hughson, R. L.

    2001-02-01

    Many complex systems share similar statistical characteristics. In this Letter, a turbulence analogy is proposed for the long-term heart rate variability of healthy humans. Based on such an analogy, the equivalence of an inertial range is found and a cascade model, which captures the statistical properties of the heart rate data, is given.

  2. The relationship between resting heart rate variability and heart rate recovery.

    PubMed

    Esco, Michael R; Olson, Michele S; Williford, Henry N; Blessing, Daniel L; Shannon, David; Grandjean, Peter

    2010-02-01

    There is limited research available regarding a possible relationship between resting heart rate variability (HRV) and post-exercise heart rate recovery (HRR). The aim of this study was to examine the relationship between resting HRV and HRR after maximal exercise. Sixty-six college age men participated in this study. HRV was measured in a supine position before and for 30 min after a maximal exercise test on a treadmill. HRV was assessed in the time (i.e., SDNN) and frequency (i.e., normalized HF power [HFnu] and normalized LF:HF ratio [LFnu:HFnu]) domains. Heart rate was recorded at maximal exercise (MHR), and at 1- (HR1) and 2- (HR2) min of the cool-down recovery period. HRR was determined from the difference between MHR and HR1 (HRR1) and the difference between MHR and HR2 (HRR2). No significant relationship was found between resting HRV and HRR1 or HRR2. However, SDNN was significantly inversely correlated to MHR (P < 0.05), and HFnu was significantly inversely correlated to MHR (P < 0.01), HR1 (P < 0.01), and HR2 (P < 0.05). Furthermore, MHR accounted for the greatest variation in both SDNN and HFnu (P < 0.05). Therefore, the HRV may not be related to the recovery of HR expressed as a slope (i.e., HRR) within 2 min following a maximal exercise test. This is possibly due to a significant inverse relationship between HRV and MHR, HR1 and HR2 post-maximal exercise.

  3. Validation of heart rate monitor Polar RS800 for heart rate variability analysis during exercise.

    PubMed

    Hernando, David; Garatachea, Nuria; Almeida, Rute; Casajús, Jose Antonio; Bailón, Raquel

    2016-09-27

    Heart rate variability (HRV) analysis during exercise is an interesting non-invasive tool to measure the cardiovascular response to the stress of exercise. Wearable heart rate monitors are a comfortable option to measure RR intervals while doing physical activities. It is necessary to evaluate the agreement between HRV parameters derived from the RR series recorded by wearable devices and those derived from an ECG during dynamic exercise of low to high intensity.23 male volunteers performed an exercise stress test on a cycle ergometer. Subjects wore a Polar RS800 device while ECG was also recorded simultaneously to extract the reference RR intervals. A time-frequency spectral analysis was performed to extract the instantaneous mean heart rate (HRM), and the power of low frequency (PLF) and high frequency (PHF) components, the latter centred on the respiratory frequency. Analysis was done in intervals of different exercise intensity based on oxygen consumption. Linear correlation, reliability and agreement were computed in each interval.The agreement between the RR series obtained from the Polar device and from the ECG is high throughout the whole test, although the shorter the RR is, the more differences there are. Both methods are interchangeable when analysing HRV at rest. At high exercise intensity, HRM and PLF still presented a high correlation (ρ>0.8) and excellent reliability and agreement indices (above 0.9). However, the PHF measurements from the Polar showed reliability and agreement coefficients around 0.5 or lower when the level of the exercise increases (for levels of O2 above 60%).

  4. Effects of different training amplitudes on heart rate and heart rate variability in young rowers.

    PubMed

    Vaz, Marcelo S; Picanço, Luan M; Del Vecchio, Fabrício B

    2014-10-01

    The aim of this study was to investigate the autonomic nervous system recovery and the psychological response as a result of 3 training amplitudes on heart rate (HR), heart rate variability (HRV), and rate of perceived exertion (RPE) in rowing. Eight young rowers (16.8 ± 1.4 years) performed, in a randomized fashion, 2 sessions of high-intensity interval training, with high and low amplitude and a continuous training (CT) session, with the same exercise duration (10 minutes) and mean intensity (60% of maximal stroke test). The data of HR, HRV, and RPE were collected 5 minutes before, immediately after each session, and 24 hours later. High amplitude promoted higher impact in maximum HR (p ≤ 0.05) and RPE (p < 0.001) when compared with CT. For the time domain HRV variable, there was a statistically significant difference between moments of rest (pretraining or post 24 hours) and posttraining in all training sessions. Originally, we conclude that training with higher load variation between effort and recovery impacts HRV, HR, and RPE with greater intensity, but the younger rowers were ready for new training sessions 24 hours after either training method. Coaches can use the polarized training method, observing the stimulus nature and time required for recovery, because it may be an adequate strategy for the development of rower's conditioning.

  5. Effect of early bereavement on heart rate and heart rate variability.

    PubMed

    Buckley, Thomas; Stannard, Angela; Bartrop, Roger; McKinley, Sharon; Ward, Christopher; Mihailidou, Anastasia Susie; Morel-Kopp, Marie-Christie; Spinaze, Monica; Tofler, Geoffrey

    2012-11-01

    Early bereavement is associated with increased cardiovascular events. The mechanism, however, has not been well studied. We assessed whether bereavement is associated with an increased heart rate (HR) and decreased heart rate variability that might contribute to increased cardiovascular risk. A total of 78 bereaved spouses and parents (55 women and 23 men; aged 34 to 87 years, mean 65) were studied with 24-hour Holter monitoring within 2 weeks of bereavement (acute) and at 6 months. Their findings were compared to those from a nonbereaved reference group (52 women and 27 men) aged 33 to 91 years (mean 63.6). All participants were in sinus rhythm. We assessed the mean HR, atrial and ventricular arrhythmias, and both time and frequency domain heart rate variability measures. Acute bereavement was associated with increased 24-hour HR (mean ± SE, 75.1 ± 1.1 vs 70.7 ± 1.0; p = 0.004) and reduced heart rate variability, as indicated by lower standard deviation of the NN intervals index (median 45.4 vs 49.9, p = 0.017), total power (7.78 ± 0.10 vs 8.02 ± 0.09, p = 0.03), very low frequency (7.23 ± 0.09 vs 7.44, p = 0.046) and low frequency (5.76 ± 0.12 vs 6.16 ± 0.09, p = 0.01). At 6 months, the bereaved had a significantly lower HR (p = 0.001) and increased standard deviation of the NN intervals index (p = 0.02), square root of the mean square of differences of successive intervals (p = 0.045), number of interval differences of successive NN intervals >50 ms divided by the number of NN intervals (p = 0.039), low-frequency power (p = 0.02), and high frequency (p = 0.002) compared to the initial acute levels. In conclusion, the present study, the first to report 24-hour HR monitoring in the early weeks of bereavement, has demonstrated increased HR and altered autonomic function that might contribute to the increased cardiovascular events in early bereavement.

  6. Effects of Tai Chi exercise on heart rate variability.

    PubMed

    Cole, Aimee R; Wijarnpreecha, Karn; Chattipakorn, Siriporn C; Chattipakorn, Nipon

    2016-05-01

    Tai Chi is a callisthenic exercise form that incorporates aerobic exercise with diaphragmatic breathing. These two aspects alone have been shown to enhance the heart rate variability, warranting research into the effects of Tai Chi on autonomic nervous system modulation and heart rate variability. A low heart rate variability has been shown to be indicative of compromised health. Any methods to enhance the heart rate variability, in particular, non-pharmacological methods, are therefore seen as beneficial to health and are sought after. The aim of this review was to comprehensively summarize the currently published studies regarding the effects of Tai Chi on heart rate variability. Both consistent and inconsistent findings are presented and discussed, and an overall conclusion attained which could benefit future clinical studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Assessing Heart Rate in Physical Education. Assessment Series: K-12 Physical Education.

    ERIC Educational Resources Information Center

    Buck, Marilyn M.

    This guide discusses the assessment of heart rate and, in particular, the assessment of heart rate using a heart monitor. Part 1, "Foundation for the Use of Heart Rate," reviews literature about heart rate assessment and heart rate monitors, offering an overview of national guidelines for physical activity. It focuses on the importance…

  8. Assessing Heart Rate in Physical Education. Assessment Series: K-12 Physical Education.

    ERIC Educational Resources Information Center

    Buck, Marilyn M.

    This guide discusses the assessment of heart rate and, in particular, the assessment of heart rate using a heart monitor. Part 1, "Foundation for the Use of Heart Rate," reviews literature about heart rate assessment and heart rate monitors, offering an overview of national guidelines for physical activity. It focuses on the importance…

  9. Dynamic nonlinear vago-sympathetic interaction in regulating heart rate.

    PubMed

    Sunagawa, K; Kawada, T; Nakahara, T

    1998-01-01

    Although the characteristics of the static interactions between the sympathetic and parasympathetic nervous systems in regulating heart rate have been well established, how the dynamic interaction modulates the heart rate response remains unknown. Thus, we investigated the dynamic interaction by estimating the transfer function from nerve stimulation to heart rate, using band-limited Gaussian white noise, in anesthetized rabbits. Concomitant tonic vagal stimulation at 5 and 10 Hz increased the gain of the transfer function relating dynamic sympathetic stimulation to heart rate by 55.0%+/-40.1% and 80.7%+/-50.5%, respectively (P < 0.05). Concomitant tonic sympathetic stimulation at 5 and 10 Hz increased the gain of the transfer function relating dynamic vagal stimulation to heart rate by 18.2%+/-17.9% and 24.1%+/-18.0%, respectively (P < 0.05). Such bidirectional augmentation was also observed during simultaneous dynamic stimulation of the sympathetic and vagal nerves independent of their stimulation patterns. Because of these characteristics, changes in sympathetic or vagal tone alone can alter the dynamic heart rate response to stimulation of the other nerve. We explained this phenomenon by assuming a sigmoidal static relationship between autonomic nerve activity and heart rate. To confirm this assumption, we identified the static and dynamic characteristics of heart rate regulation by a neural network analysis, using large-amplitude Gaussian white noise input. To examine the mechanism involved in the bidirectional augmentation, we increased cytosolic adenosine 3',5'-cyclic monophosphate (cAMP) at the postjunctional effector site by applying pharmacological interventions. The cAMP accumulation increased the gain of the transfer function relating dynamic vagal stimulation to heart rate. Thus, accumulation of cAMP contributes, at least in part, to the sympathetic augmentation of the dynamic vagal control of heart rate.

  10. Fetal development assessed by heart rate patterns--time scales of complex autonomic control.

    PubMed

    Hoyer, Dirk; Nowack, Samuel; Bauer, Stephan; Tetschke, Florian; Ludwig, Stefan; Moraru, Liviu; Rudoph, Anja; Wallwitz, Ulrike; Jaenicke, Franziska; Haueisen, Jens; Schleussner, Ekkehard; Schneider, Uwe

    2012-03-01

    The increasing functional integrity of the organism during fetal maturation is connected with increasing complex internal coordination. We hypothesize that time scales of complexity and dynamics of heart rate patterns reflect the increasing inter-dependencies within the fetal organism during its prenatal development. We investigated multi-scale complexity, time irreversibility and fractal scaling from 73 fetal magnetocardiographic 30min recordings over the third trimester. We found different scale dependent complexity changes, increasing medium scale time irreversibility, and increasing long scale fractal correlations (all changes p<0.05). The results confirm the importance of time scales to be considered in fetal heart rate based developmental indices.

  11. Effect of adenosine on heart rate in isolated muskrat and guinea pig hearts.

    PubMed

    McKean, T A; Sterling, H; Streeby, D R; Lynch, A E; Lacroix, C; Vestal, R E

    1993-07-01

    The purpose of this study was to compare the responses of isolated hearts of the diving muskrat with the nondividing guinea pig (GP) to determine the contribution of adenosine (ADO) to the profound bradycardia that was seen in isolated muskrat hearts during exposure to hypoxia. Muskrat hearts were more sensitive than GP hearts to the heart rate-lowering effects of exogenously applied ADO or a stable ADO analogue, (R)-N6-(phenylisopropyl)adenosine. The hearts of both species were unpaced, and the bradycardia appeared to be due to high degree of atrioventricular block. Radioligand binding with 8-cyclopentyl-1,3-[3H]dipropylxanthine to A1-ADO receptors was greater in cardiac membranes prepared from GP hearts than from muskrat hearts. Nucleoside transporter antagonist binding was also greater in GP hearts compared with muskrats. This was determined by membrane binding of [3H]-nitrobenzylthioinosine, an antagonist of nucleoside transport. Both muskrat and GP hearts responded to 30 min of hypoxic perfusion by releasing ADO into the coronary effluent; however, the muskrat hearts released approximately five times more than the GP hearts. When hearts were subjected to hypoxia in the presence of ADO deaminase, theophylline, or 8-(p-sulfophenyl)theophylline, the hypoxia-induced bradycardia was blocked in the GP hearts and either slightly reduced or not affected in muskrat hearts. In contrast to GP hearts, muskrat hearts release larger amounts of ADO during hypoxia and are more sensitive to the negative chronotropic effects of exogenously administered ADO; yet the hypoxia-induced bradycardia does not appear to be exclusively mediated by ADO in the muskrat as it is in the isolated GP heart.

  12. Effects of Exercise During Pregnancy on Maternal Heart Rate and Heart Rate Variability.

    PubMed

    May, Linda E; Knowlton, Jennifer; Hanson, Jessica; Suminski, Richard; Paynter, Christopher; Fang, Xiangming; Gustafson, Kathleen M

    2016-07-01

    Pregnancy is associated with an increased sympathetic state, which can be exacerbated by gestational conditions. Research has shown that exercise during pregnancy lowers heart rate (HR) and can attenuate the symptoms of gestational conditions associated with increased sympathetic control. However, changes in maternal heart autonomic function in response to exercise have not been reported across multiple time points during pregnancy. This analysis is designed to address this gap. To determine if exercise throughout gestation improves maternal cardiac autonomic nervous system functioning, as evidenced by decreased HR and increased heart rate variability (HRV) indices. Case control study. Academic medical institution. A total of 56 women with healthy, singleton, low-risk pregnancies. Participants were asked to complete 3 resting 18-minute HRV recordings at 28, 32, and 36 weeks' gestation, along with a physical activity questionnaire. HRV indices were calculated for time (R peak to R peak interval standard deviation and root mean squared of successive differences) and frequency (very low, low, and high frequency) domain measures. The differences between groups were compared for HRV indices at 28, 32, and 36 weeks. Resting HR was significantly lower in the exercise group at 28 weeks (P < .01) compared with the control group. The exercise group had significantly (P < .05) increased measures of resting HRV time domain measures at 28, 32, and 36 weeks' gestation compared with the control group. Resting HRV power was significantly increased (P < .05) in all frequency domain measures at 32 weeks in the exercise group relative to the control group. No differences occurred in sympathovagal balance (low frequency/high frequency ratio) between groups. Exercise throughout pregnancy can significantly improve cardiac autonomic control. More research is needed to determine if this adaptation to exercise may reduce the risk of adverse outcomes associated with gestational conditions

  13. Aerobic Exercise during Pregnancy and Presence of Fetal-Maternal Heart Rate Synchronization

    PubMed Central

    Van Leeuwen, Peter; Gustafson, Kathleen M.; Cysarz, Dirk; Geue, Daniel; May, Linda E.; Grönemeyer, Dietrich

    2014-01-01

    It has been shown that short-term direct interaction between maternal and fetal heart rates may take place and that this interaction is affected by the rate of maternal respiration. The aim of this study was to determine the effect of maternal aerobic exercise during pregnancy on the occurrence of fetal-maternal heart rate synchronization. Methods In 40 pregnant women at the 36th week of gestation, 21 of whom exercised regularly, we acquired 18 min. RR interval time series obtained simultaneously in the mothers and their fetuses from magnetocardiographic recordings. The time series of the two groups were examined with respect to their heart rate variability, the maternal respiratory rate and the presence of synchronization epochs as determined on the basis of synchrograms. Surrogate data were used to assess whether the occurrence of synchronization was due to chance. Results In the original data, we found synchronization occurred less often in pregnancies in which the mothers had exercised regularly. These subjects also displayed higher combined fetal-maternal heart rate variability and lower maternal respiratory rates. Analysis of the surrogate data showed shorter epochs of synchronization and a lack of the phase coordination found between maternal and fetal beat timing in the original data. Conclusion The results suggest that fetal-maternal heart rate coupling is present but generally weak. Maternal exercise has a damping effect on its occurrence, most likely due to an increase in beat-to-beat differences, higher vagal tone and slower breathing rates. PMID:25162592

  14. Aerobic exercise during pregnancy and presence of fetal-maternal heart rate synchronization.

    PubMed

    Van Leeuwen, Peter; Gustafson, Kathleen M; Cysarz, Dirk; Geue, Daniel; May, Linda E; Grönemeyer, Dietrich

    2014-01-01

    It has been shown that short-term direct interaction between maternal and fetal heart rates may take place and that this interaction is affected by the rate of maternal respiration. The aim of this study was to determine the effect of maternal aerobic exercise during pregnancy on the occurrence of fetal-maternal heart rate synchronization. In 40 pregnant women at the 36th week of gestation, 21 of whom exercised regularly, we acquired 18 min. RR interval time series obtained simultaneously in the mothers and their fetuses from magnetocardiographic recordings. The time series of the two groups were examined with respect to their heart rate variability, the maternal respiratory rate and the presence of synchronization epochs as determined on the basis of synchrograms. Surrogate data were used to assess whether the occurrence of synchronization was due to chance. In the original data, we found synchronization occurred less often in pregnancies in which the mothers had exercised regularly. These subjects also displayed higher combined fetal-maternal heart rate variability and lower maternal respiratory rates. Analysis of the surrogate data showed shorter epochs of synchronization and a lack of the phase coordination found between maternal and fetal beat timing in the original data. The results suggest that fetal-maternal heart rate coupling is present but generally weak. Maternal exercise has a damping effect on its occurrence, most likely due to an increase in beat-to-beat differences, higher vagal tone and slower breathing rates.

  15. Heart Rate Dependency of Large Artery Stiffness.

    PubMed

    Tan, Isabella; Spronck, Bart; Kiat, Hosen; Barin, Edward; Reesink, Koen D; Delhaas, Tammo; Avolio, Alberto P; Butlin, Mark

    2016-07-01

    Carotid-femoral pulse wave velocity (cfPWV) quantifies large artery stiffness, it is used in hemodynamic research and is considered a useful cardiovascular clinical marker. cfPWV is blood pressure (BP) dependent. Intrinsic heart rate (HR) dependency of cfPWV is unknown because increasing HR is commonly accompanied by increasing BP. This study aims to quantify cfPWV dependency on acute, sympathovagal-independent changes in HR, independent of BP. Individuals (n=52, age 40-93 years, 11 female) with in situ cardiac pacemakers or cardioverter defibrillators were paced at 60, 70, 80, 90, and 100 bpm. BP and cfPWV were measured at each HR. Both cfPWV (mean [95% CI], 0.31 [0.26-0.37] m/s per 10 bpm; P<0.001) and central aortic diastolic pressure (3.78 [3.40-4.17] mm Hg/10 bpm; P<0.001) increased with HR. The HR effect on cfPWV was isolated by correcting the BP effects by 3 different methods: (1) statistically, by a linear mixed model; (2) mathematically, using an exponential relationship between BP and cross-sectional lumen area; and (3) using measured BP dependency of cfPWV derived from changes in BP induced by orthostatic changes (seated and supine) in a subset of subjects (n=17). The BP-independent effects of HR on cfPWV were quantified as 0.20 [0.11-0.28] m/s per 10 bpm (P<0.001, method 1), 0.16 [0.11-0.22] m/s per 10 bpm (P<0.001, method 2), and 0.16 [0.11-0.21] m/s per 10 bpm (P<0.001, method 3). With a mean HR dependency in the range of 0.16 to 0.20 m/s per 10 bpm, cfPWV may be considered to have minimal physiologically relevant changes for small changes in HR, but larger differences in HR must be considered as contributing to significant differences in cfPWV.

  16. Firefighter Incident Rehabilitation: Interpreting Heart Rate Responses.

    PubMed

    Smith, Denise L; Haller, Jeannie M; Benedict, Ron; Moore-Merrell, Lori

    2016-01-01

    The primary objective of this observational study was to document the heart rate (HR) responses of firefighters during incident rehabilitation following firefighting activity in a high-rise building with a simulated fire on the 10th floor. Additionally, the study investigated potential factors, including firefighting workload, ambient temperature, firefighter movement, and individual characteristics, that may have affected HR during recovery. Firefighters (n = 198) were assigned to perform a simulation of fire suppression, search and rescue, or material support during one of six firefighting trials that involved different crew sizes and ascent modes, and were performed in different environmental conditions. After completing the simulated firefighting activity, firefighters reported to a rehabilitation area on the 8th floor. The rehabilitation area was staffed by firefighter/paramedics. HR was monitored continuously during simulated firefighting activity and a 15-minute rehabilitation period. Average HR during rehabilitation (HRmean) was calculated and compared across trials. Simulated firefighting activity was performed in the summer in Virginia, USA, and ambient conditions varied among trials (mean ± SD: 31 ± 4°C; 46 ± 15% relative humidity; 32 ± 4°C heat index). Duration of simulated firefighting activity ranged from 12.0 to 20.3 minutes among trials (mean: 15.4 ± 5.2 minutes). Over all trials, mean peak HR during simulations was 173 ± 18 beats·min(-1). Mean HR over all trials at entry into rehabilitation was 149 ± 24 beats·min(-1). Following 15 minutes of recovery, mean HR over all trials was 126 ± 23 beats·min(-1). Exploratory analyses revealed that higher workload during firefighting (stair trials), higher ambient temperature (≥30°C), greater movement during rehabilitation (≥0.1 g-force), higher age (≥45 years), and higher BMI (≥30.0 kg·m(-2)) were associated with higher HR responses during rehabilitation. During complex emergency

  17. Fighter pilots' heart rate, heart rate variation and performance during instrument approaches.

    PubMed

    Mansikka, Heikki; Simola, Petteri; Virtanen, Kai; Harris, Don; Oksama, Lauri

    2016-10-01

    Fighter pilots' heart rate (HR), heart rate variation (HRV) and performance during instrument approaches were examined. The subjects were required to fly instrument approaches in a high-fidelity simulator under various levels of task demand. The task demand was manipulated by increasing the load on the subjects by reducing the range at which they commenced the approach. HR and the time domain components of HRV were used as measures of pilot mental workload (PMWL). The findings of this study indicate that HR and HRV are sensitive to varying task demands. HR and HRV were able to distinguish the level of PMWL after which the subjects were no longer able to cope with the increasing task demands and their instrument landing system performance fell to a sub-standard level. The major finding was the HR/HRV's ability to differentiate the sub-standard performance approaches from the high-performance approaches. Practitioner Summary: This paper examined if HR and HRV were sensitive to varying task demands in a fighter aviation environment and if these measures were related to variations in pilot's performance.

  18. Heart rate and heart rate variability modification in chronic insomnia patients.

    PubMed

    Farina, Benedetto; Dittoni, Serena; Colicchio, Salvatore; Testani, Elisa; Losurdo, Anna; Gnoni, Valentina; Di Blasi, Chiara; Brunetti, Riccardo; Contardi, Anna; Mazza, Salvatore; Della Marca, Giacomo

    2014-01-01

    Chronic insomnia is highly prevalent in the general population, provoking personal distress and increased risk for psychiatric and medical disorders. Autonomic hyper-arousal could be a pathogenic mechanism of chronic primary insomnia. The aim of this study was to investigate autonomic activity in patients with chronic primary insomnia by means of heart rate variability (HRV) analysis. Eighty-five consecutive patients affected by chronic primary insomnia were enrolled (38 men and 47 women; mean age: 53.2 ± 13.6). Patients were compared with a control group composed of 55 healthy participants matched for age and gender (23 men and 32 women; mean age: 54.2 ± 13.9). Patients underwent an insomnia study protocol that included subjective sleep evaluation, psychometric measures, and home-based polysomnography with evaluation of HRV in wake before sleep, in all sleep stages, and in wake after final awakening. Patients showed modifications of heart rate and HRV parameters, consistent with increased sympathetic activity, while awake before sleep and during Stage-2 non-REM sleep. No significant differences between insomniacs and controls could be detected during slow-wave sleep, REM sleep, and post-sleep wake. These results are consistent with the hypothesis that autonomic hyper-arousal is a major pathogenic mechanism in primary insomnia, and confirm that this condition is associated with an increased cardiovascular risk.

  19. The effect of relaxing massage on heart rate and heart rate variability in purebred Arabian racehorses.

    PubMed

    Kowalik, Sylwester; Janczarek, Iwona; Kędzierski, Witold; Stachurska, Anna; Wilk, Izabela

    2016-09-04

    The objective of this study was to assess the effect of relaxing massage on the heart rate (HR) and heart rate variability (HRV) in young racehorses during their first racing season. In the study, 72 Purebred Arabian racehorses were included. The study was implemented during the full race season. The horses from control and experimental groups were included in regular race training 6 days a week. The horses from the experimental group were additionally subject to the relaxing massage 3 days a week during the whole study. HR and HRV were assumed as indicators of the emotional state of the horses. The measurements were taken six times, every 4-5 weeks. The HRV parameters were measured at rest, during grooming and saddling the horse and during warm-up walking under a rider. The changes of the parameters throughout the season suggest that the relaxing massage may be effectively used to make the racehorses more relaxed and calm. Moreover, the horses from the experimental group had better race performance records.

  20. Improvements in fetal heart rate analysis by the removal of maternal-fetal heart rate ambiguities.

    PubMed

    Pinto, Paula; Costa-Santos, Cristina; Gonçalves, Hernâni; Ayres-De-Campos, Diogo; Bernardes, João

    2015-11-19

    Misinterpretation of the maternal heart rate (MHR) as fetal may lead to significant errors in fetal heart rate (FHR) interpretation. In this study we hypothesized that the removal of these MHR-FHR ambiguities would improve FHR analysis during the final hour of labor. Sixty-one MHR and FHR recordings were simultaneously acquired in the final hour of labor. Removal of MHR-FHR ambiguities was performed by subtracting MHR signals from their FHR counterparts when the absolute difference between the two was less or equal to 5 beats per minute. Major MHR-FHR ambiguities were defined when they exceeded 1% of the tracing. Maternal, fetal and neonatal characteristics were evaluated in cases where major MHR-FHR ambiguities occurred and computer analysis of FHR recordings was compared, before and after removal of the ambiguities. Seventy-two percent of tracings (44/61) exhibited episodes of major MHR-FHR ambiguities, which were not significantly associated with any maternal, fetal or neonatal characteristics, but were associated with MHR accelerations, FHR signal loss and decelerations. Removal of MHR-FHR ambiguities resulted in a significant decrease in FHR decelerations, and improvement in FHR tracing classification. FHR interpretation during the final hour of labor can be significantly improved by the removal of MHR-FHR ambiguities.

  1. Heart rate differentiates urgency and emergency in hypertensive crisis.

    PubMed

    Al Bannay, Rashed; Böhm, Michael; Husain, Aysha

    2013-08-01

    To study the clinical significance of presenting blood pressure parameters and heart rate in patients with hypertensive crisis. In patients admitted with hypertensive crisis between January 2011 and May 2011, demography, mode of presentation, co-morbidities, blood pressure readings, and heart rate at presentation were documented. Further clustering of hypertensive crisis into emergency or urgency was based on the presence or absence of target organ involvement. The relationship between blood pressure parameters, heart rate, and other variables was analyzed. 189 patients in sinus rhythm were enrolled in this pilot study. The rate of hypertensive urgency was 56 %, whereas the rate of hypertensive emergency was 44 %, respectively. Subjects with hypertensive emergency had a higher mean heart rate (93 ± 22.7 bpm) than those with urgency (81 ± 11.5 bpm) (P = 0.015). Women had higher heart rates (92 ± 18.5 bpm) than men (86 ± 17.6 bpm) (P = 0.014). Heart rates below 100 bpm had a specificity of 94 %, classifying patients as hypertensive urgency. Tachycardia had a powerful statistical association with hypertensive left ventricular failure (P < 0.0001). Other hemodynamic parameters, including systolic blood pressure, diastolic blood pressure, pulse pressure, and mean blood pressure relates neither to urgency nor to emergency. Diabetic patients with HBA1c levels of more than 53 mmol/mol had a heart rate of more than 100 bpm (P = 0.015) during hypertensive crisis. Normal heart rate is characteristic of hypertensive urgency. Tachycardia in this setting is an ominous sign and denotes hypertensive complications in particular left ventricular failure. Among diabetics, elevated heart rate is associated with poor glycemic control.

  2. Effect of yoga therapy on heart rate, blood pressure and cardiac autonomic function in heart failure.

    PubMed

    Krishna, Bandi Hari; Pal, Pravati; G K, Pal; J, Balachander; E, Jayasettiaseelon; Y, Sreekanth; M G, Sridhar; G S, Gaur

    2014-01-01

    It is well known that a hall mark of heart failure is adverse changes in autonomic function. Elevated blood pressure is a powerful predictor of congestive heart failure and other Cardiovascular Disease (CVD) outcomes. In this study, we planned to examine the effects of a 12 week yoga therapy on blood pressure, heart rate, heart rate variability, and rate pressure product (RPP). Out of 130 heart failure patients recruited for the study, 65 patients were randomly selected to receive 12 week yoga therapy along with standard medical therapy (yoga group). Other patients (n=65) received only standard medical therapy (control group). Heart rate, blood pressure, cardiac autonomic function (by short-term heart-rate variability analysis) and myocardial oxygen consumption (by RPP) were assessed before and after 12 weeks. In the yoga group, 44 patients and in the control group, 48 patients completed the study. There was a significant decrease in heart rate, blood pressure and RPP in yoga group compared to control group. Also, LFnu and LF-HF ratio decreased significantly and HFnu increased significantly in yoga group compared to control group. Twelve-week yoga therapy significantly improved the parasympathetic activity and decreased the sympathetic activity in heart failure patients (NYHA I&II).

  3. Learning by Heart: Students Use Heart Rate Patterns To Identify Nervous System Imbalances.

    ERIC Educational Resources Information Center

    Ackerly, Spafford C.

    2001-01-01

    Introduces a science unit on heart rate variability (HVR) patterns. Uses spectral analysis to determine the effects of environmental stimulants such as music and emotional stress on heart rate. Observes relaxation techniques and their effects on the autonomous nervous system. (Contains 12 references.) (YDS)

  4. Using complexity metrics with R-R intervals and BPM heart rate measures.

    PubMed

    Wallot, Sebastian; Fusaroli, Riccardo; Tylén, Kristian; Jegindø, Else-Marie

    2013-01-01

    Lately, growing attention in the health sciences has been paid to the dynamics of heart rate as indicator of impending failures and for prognoses. Likewise, in social and cognitive sciences, heart rate is increasingly employed as a measure of arousal, emotional engagement and as a marker of interpersonal coordination. However, there is no consensus about which measurements and analytical tools are most appropriate in mapping the temporal dynamics of heart rate and quite different metrics are reported in the literature. As complexity metrics of heart rate variability depend critically on variability of the data, different choices regarding the kind of measures can have a substantial impact on the results. In this article we compare linear and non-linear statistics on two prominent types of heart beat data, beat-to-beat intervals (R-R interval) and beats-per-min (BPM). As a proof-of-concept, we employ a simple rest-exercise-rest task and show that non-linear statistics-fractal (DFA) and recurrence (RQA) analyses-reveal information about heart beat activity above and beyond the simple level of heart rate. Non-linear statistics unveil sustained post-exercise effects on heart rate dynamics, but their power to do so critically depends on the type data that is employed: While R-R intervals are very susceptible to non-linear analyses, the success of non-linear methods for BPM data critically depends on their construction. Generally, "oversampled" BPM time-series can be recommended as they retain most of the information about non-linear aspects of heart beat dynamics.

  5. Using complexity metrics with R-R intervals and BPM heart rate measures

    PubMed Central

    Wallot, Sebastian; Fusaroli, Riccardo; Tylén, Kristian; Jegindø, Else-Marie

    2013-01-01

    Lately, growing attention in the health sciences has been paid to the dynamics of heart rate as indicator of impending failures and for prognoses. Likewise, in social and cognitive sciences, heart rate is increasingly employed as a measure of arousal, emotional engagement and as a marker of interpersonal coordination. However, there is no consensus about which measurements and analytical tools are most appropriate in mapping the temporal dynamics of heart rate and quite different metrics are reported in the literature. As complexity metrics of heart rate variability depend critically on variability of the data, different choices regarding the kind of measures can have a substantial impact on the results. In this article we compare linear and non-linear statistics on two prominent types of heart beat data, beat-to-beat intervals (R-R interval) and beats-per-min (BPM). As a proof-of-concept, we employ a simple rest-exercise-rest task and show that non-linear statistics—fractal (DFA) and recurrence (RQA) analyses—reveal information about heart beat activity above and beyond the simple level of heart rate. Non-linear statistics unveil sustained post-exercise effects on heart rate dynamics, but their power to do so critically depends on the type data that is employed: While R-R intervals are very susceptible to non-linear analyses, the success of non-linear methods for BPM data critically depends on their construction. Generally, “oversampled” BPM time-series can be recommended as they retain most of the information about non-linear aspects of heart beat dynamics. PMID:23964244

  6. Thermal Acclimation of Heart Rates in Reptilian Embryos

    PubMed Central

    Du, Wei-Guo; Ye, Hua; Zhao, Bo; Warner, Daniel A.; Shine, Richard

    2010-01-01

    In many reptiles, the thermal regimes experienced by eggs in natural nests vary as a function of ambient weather and location, and this variation has important impacts on patterns of embryonic development. Recent advances in non-invasive measurement of embryonic heart rates allow us to answer a long-standing puzzle in reptilian developmental biology: Do the metabolic and developmental rates of embryos acclimate to local incubation regimes, as occurs for metabolic acclimation by post-hatching reptiles? Based on a strong correlation between embryonic heart rate and oxygen consumption, we used heart rates as a measure of metabolic rate. We demonstrate acclimation of heart rates relative to temperature in embryos of one turtle, one snake and one lizard species that oviposit in relatively deep nests, but found no acclimation in another lizard species that uses shallow (and hence, highly thermally variable) nests. Embryonic thermal acclimation thus is widespread, but not ubiquitous, within reptiles. PMID:21179473

  7. Thermal acclimation of heart rates in reptilian embryos.

    PubMed

    Du, Wei-Guo; Ye, Hua; Zhao, Bo; Warner, Daniel A; Shine, Richard

    2010-12-14

    In many reptiles, the thermal regimes experienced by eggs in natural nests vary as a function of ambient weather and location, and this variation has important impacts on patterns of embryonic development. Recent advances in non-invasive measurement of embryonic heart rates allow us to answer a long-standing puzzle in reptilian developmental biology: Do the metabolic and developmental rates of embryos acclimate to local incubation regimes, as occurs for metabolic acclimation by post-hatching reptiles? Based on a strong correlation between embryonic heart rate and oxygen consumption, we used heart rates as a measure of metabolic rate. We demonstrate acclimation of heart rates relative to temperature in embryos of one turtle, one snake and one lizard species that oviposit in relatively deep nests, but found no acclimation in another lizard species that uses shallow (and hence, highly thermally variable) nests. Embryonic thermal acclimation thus is widespread, but not ubiquitous, within reptiles.

  8. Stochastic heart-rate model can reveal pathologic cardiac dynamics

    NASA Astrophysics Data System (ADS)

    Kuusela, Tom

    2004-03-01

    A simple one-dimensional Langevin-type stochastic difference equation can simulate the heart-rate fluctuations in a time scale from minutes to hours. The model consists of a deterministic nonlinear part and a stochastic part typical of Gaussian noise, and both parts can be directly determined from measured heart-rate data. Data from healthy subjects typically exhibit the deterministic part with two or more stable fixed points. Studies of 15 congestive heart-failure subjects reveal that the deterministic part of pathologic heart dynamics has no clear stable fixed points. Direct simulations of the stochastic model for normal and pathologic cases can produce statistical parameters similar to those of real subjects. Results directly indicate that pathologic situations simplify the heart-rate control system.

  9. Optimized Treatment and Heart Rate Reduction in Chronic Heart Failure

    PubMed Central

    Moreno, Irineu Blanco; Del Carlo, Carlos Henrique; Pereira-Barretto, Antônio Carlos

    2013-01-01

    Background Heart failure (HF) is a syndrome that leads to poor outcome in advanced forms. The neurohormonal blockade modifies this natural history; however, it is often suboptimal. Objective The aim of this study is to assess at what percentage cardiologists used to treating HF can prescribe target doses of drugs of proven efficacy. Methods A total of 104 outpatients with systolic dysfunction were consecutively enrolled, all under stabilized treatment. Demographic and treatment data were evaluated and the doses achieved were verified. The findings are shown as percentages and correlations are made between different variables. Results The mean age of patients was 64.1 ± 14.2 years, with SBP =115.4 ± 15.3, HR = 67.8 ± 9.4 bpm, weight = 76.0 ± 17.0 kg and sinus rhythm (90.4%). As for treatment, 93.3% received a RAS blocker (ACEI 52.9%), all received beta-blockers (BB), the most often prescribed being carvedilol (92.3%). As for the doses: 97.1% of those receiving an ARB were below the optimal dose and of those who received ACEI, 52.7% received an optimized dose. As for the BB, target doses were prescribed to 76.0% of them. In this group of patients, most with BB target dose, it can be seen that 36.5% had HR ≥ 70 bpm in sinus rhythm. Conclusion Cardiologists used to treating HF can prescribe target doses of ACEI and BB to most patients. Even though they receive the recommended doses, about one third of patients persists with HR > 70 bpm and should have their treatment optimized. PMID:24100693

  10. Phase Transition in a Healthy Human Heart Rate

    NASA Astrophysics Data System (ADS)

    Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Togo, Fumiharu; Yamamoto, Yoshiharu

    2005-07-01

    A healthy human heart rate displays complex fluctuations which share characteristics of physical systems in a critical state. We demonstrate that the human heart rate in healthy individuals undergoes a dramatic breakdown of criticality characteristics, reminiscent of continuous second order phase transitions. By studying the germane determinants, we show that the hallmark of criticality—highly correlated fluctuations—is observed only during usual daily activity, and a breakdown of these characteristics occurs in prolonged, strenuous exercise and sleep. This finding is the first reported discovery of the dynamical phase transition phenomenon in a biological control system and will be a key to understanding the heart rate control system in health and disease.

  11. Scaling Behaviour and Memory in Heart Rate of Healthy Human

    NASA Astrophysics Data System (ADS)

    Cai, Shi-Min; Peng, Hu; Yang, Hui-Jie; Zhou, Tao; Zhou, Pei-Ling; Wang, Bing-Hong

    2007-10-01

    We investigate a set of complex heart rate time series from healthy human in different behaviour states with the detrended fluctuation analysis and diffusion entropy (DE) method. It is proposed that the scaling properties are influenced by behaviour states. The memory detected by DE exhibits an approximately same pattern after a detrending procedure. Both of them demonstrate the long-range strong correlations in heart rate. These findings may be helpful to understand the underlying dynamical evolution process in the heart rate control system, as well as to model the cardiac dynamic process.

  12. Interaction Between Heart Rate Variability and Heart Rate in Pediatric Population

    PubMed Central

    Gąsior, Jakub S.; Sacha, Jerzy; Jeleń, Piotr J.; Pawłowski, Mariusz; Werner, Bożena; Dąbrowski, Marek J.

    2015-01-01

    Background: Heart rate variability (HRV) is primarily heart rate (HR) dependent, and therefore, different HR may exert different impact on HRV. The objectives of the study were to evaluate the effect of HR on HRV in children and to determine whether HRV indices normalized to HR are sex- and age-related. Methods: Short-term ECG recordings were performed in 346 healthy children. Standard time and frequency domain HRV parameters and HR were analyzed in four age subgroups (6–7, 8–9, 10–11, and 12–13 years old). To investigate the HR impact on HRV, standard HRV parameters were normalized to prevailing HR. Results: Standard HRV measures did not differ between age subgroups, however, HR significantly decreased with subjects age and turned out to be the strongest determinant of HRV. The normalization of HRV to prevailing HR allowed to show that sex-related differences in standard HRV resulted from differences in HR between boys and girls. The normalized HRV significantly decreased with age—before the normalization this effect was masked by age-related HR alterations. Conclusions: HR significantly impacts HRV in pediatric population and turns out to be the strongest determinant of all standard HRV indices. The differences in standard HRV between boys and girls result from differences in their HR. The normalized HRV is decreasing with age in healthy children and it is accompanied by the reduction of HR—as a net result, the standard HRV is constant in children at different ages. This may reflect the maturation of the autonomic nervous system. PMID:26733878

  13. Dominant Parasympathetic Modulation of Heart Rate and Heart Rate Variability in a Wild-Caught Seabird.

    PubMed

    Carravieri, Alice; Müller, Martina S; Yoda, Ken; Hayama, Shin-Ichi; Yamamoto, Maki

    2016-01-01

    Heart rate (HR) and heart rate variability (HRV) provide noninvasive measures of the relative activity of the parasympathetic nervous system (PNS), which promotes self-maintenance and restoration, and the sympathetic nervous system (SNS), which prepares an animal for danger. The PNS decreases HR, whereas the SNS increases HR. The PNS and SNS also contribute to oscillations in heartbeat intervals at different frequencies, producing HRV. HRV promotes resilience and adjustment capacity in the organism to intrinsic and extrinsic changes. Measuring HRV can reveal the condition and emotional state of animals, including aspects of their stress physiology. Until now, the functioning of the PNS and SNS and their relationship with other physiological systems have been studied almost exclusively in humans. In this study, we tested their influence on HR and HRV for the first time in a wild-caught seabird, the streaked shearwater (Calonectris leucomelas). We analyzed electrocardiograms collected from birds carrying externally attached HR loggers and that received injections that pharmacologically blocked the PNS, the SNS, or both, as well as those that received a saline (sham) injection or no injection (control). The PNS strongly dominated modulation of HR and also HRV across all frequencies, whereas the SNS contributed only slightly to low-frequency oscillations. The saline injection itself acted as a stressor, causing a dramatic drop in PNS activity in HRV and an increase in HR, though PNS activity continued to dominate even during acute stress. Dominant PNS activity is expected for long-lived species, which should employ physiological strategies that minimize somatic deterioration coming from stress.

  14. A comparison between heart rate and heart rate variability as indicators of cardiac health and fitness.

    PubMed

    Grant, Catharina C; Murray, Carien; Janse van Rensburg, Dina C; Fletcher, Lizelle

    2013-01-01

    Quantification of cardiac autonomic activity and control via heart rate (HR) and heart rate variability (HRV) is known to provide prognostic information in clinical populations. Issues with regard to standardization and interpretation of HRV data make the use of the more easily accessible HR on its own as an indicator of autonomic cardiac control very appealing. The aim of this study was to investigate the strength of associations between an important cardio vascular health metric such as VO2max and the following: HR, HRV indicators, and HR normalized HRV indicators. A cross sectional descriptive study was done including 145 healthy volunteers aged between 18 and 22 years. HRV was quantified by time domain, frequency domain and Poincaré plot analysis. Indirect VO2max was determined using the Multistage Coopers test. The Pearson correlation coefficient was calculated to quantify the strength of the associations. Both simple linear and multiple stepwise regressions were performed to be able to discriminate between the role of the individual indicators as well as their combined association with VO2max. Only HR, RR interval, and pNN50 showed significant (p < 0.01, p < 0.01, and p = 0.03) correlations with VO2max. Stepwise multiple regression indicated that, when combining all HRV indicators the most important predictor of cardio vascular fitness as represented by VO2max, is HR. HR explains 17% of the variation, while the inclusion of HF (high frequency HRV indicator) added only an additional 3.1% to the coefficient of determination. Results also showed when testing the normalized indicators, HR explained of the largest percentage of the changes in VO2max (16.5%). Thus, HR on its own is the most important predictor of changes in an important cardiac health metric such as VO2max. These results may indicate that during investigation of exercise ability (VO2max) phenomena, quantification of HRV may not add significant value.

  15. Guided imagery, anxiety, heart rate, and heart rate variability during centrifuge training.

    PubMed

    Jing, Xiaolu; Wu, Ping; Liu, Fang; Wu, Bin; Miao, Danmin

    2011-02-01

    Centrifuge training is an important method of improving the hypergravity tolerance of pilots, cosmonauts, and Chinese astronauts. However, the concomitants of tension or anxiety often impede training. Guided imagery (GI), a mind-body relaxation technique, provides a behavioral and cognitive means whereby individuals are able to exert control over the focus of attention. This study aims to investigate the immediate effects of GI for reducing stress in centrifuge training. There were 12 healthy young men who were randomly assigned to a GI group or music group. We measured changes in heart rate during centrifuge training, in heart rate variability before and after centrifuge training, and also evaluated relaxation and anxiety in three phases: before intervention, after intervention, and following centrifuge training. The change in the pattern of anxiety was different in the two groups over the three phases. Anxiety (measured by State Anxiety Inventory) in the GI group changed from 31.7 +/- 5.9 to 26.8 +/- 2.6 and 27.8 +/- 4.1, whereas for the music group this changed from 32.2 +/- 7.6 to 31.2 +/- 8.3 and 26.8 +/- 6.8. During centrifuge training, the maximal HR for the GI group (101.2 +/- 8.8) was lower than that of the music group (123.0 +/- 19.1). In addition GI showed a decrease in low frequency (LF, 0.04-0.15 Hz) components and an increase in high frequency (HF, 0.15-0.4 Hz) components before and after centrifuge training. GI was capable of decreasing tension, anxiety, and sympathetic nervous system activity pre- or post-centrifugation.

  16. Resting heart rate variability and heart rate recovery after submaximal exercise.

    PubMed

    Danieli, Aljoša; Lusa, Lara; Potočnik, Nejka; Meglič, Bernard; Grad, Anton; Bajrović, Fajko F

    2014-04-01

    Aerobic training accelerates Heart Rate Recovery after exercise in healthy subjects and in patients with coronary disease. As shown by pharmacological autonomic blockade, HRR early after exercise is dependent primarily on parasympathetic reactivation. Thus, accelerated HRR early after exercise in endurance-trained athletes may be attributed to augmented parasympathetic reactivation. In the present study, we tested the hypothesis that the HRR early after submaximal exercise is related to the pre-exercise parasympathetic modulation. Thirty endurance-trained athletes (20 males, 50 ± 7 years) and thirty control subjects (20 males, 52 ± 6 years) performed a submaximal exercise on a cyclo-ergometer. Pre-exercise resting short-term heart rate variability (HRV) parameters in time and frequency-domains were correlated with HRR during the first 30 s, 1 and 2 min after cessation of exercise. We found that HRR was statistically significantly faster in athletes than in controls at all examination time points (p < 0.05). HF, SDNN and RMSSD were statistically significantly higher in athletes than in controls (p < 0.05), but other resting HRV parameters were not statistically different between groups. After 30 s, 1 and 2 min of recovery, HRR correlation with total power, HF, HFnu and RMSSD was positive, while the correlation with LF/HF was negative for small and positive for larger values. The opposite was true for SDNN. These findings support the hypothesis that HRR early after submaximal exercise is related to resting parasympathetic modulation in the middle-aged subjects. In addition, they suggested an optimal range of HRV for maximal HRR after exercise.

  17. Heart rate responses induced by acoustic tempo and its interaction with basal heart rate.

    PubMed

    Watanabe, Ken; Ooishi, Yuuki; Kashino, Makio

    2017-03-07

    Many studies have revealed the influences of music on the autonomic nervous system (ANS). Since previous studies focused on the effects of acoustic tempo on the ANS, and humans have their own physiological oscillations such as the heart rate (HR), the effects of acoustic tempo might depend on the HR. Here we show the relationship between HR elevation induced by acoustic tempo and individual basal HR. Since high tempo-induced HR elevation requires fast respiration, which is based on sympatho-respiratory coupling, we controlled the participants' respiration at a faster rate (20 CPM) than usual (15 CPM). We found that sound stimuli with a faster tempo than the individual basal HR increased the HR. However, the HR increased following a gradual increase in the acoustic tempo only when the extent of the gradual increase in tempo was within a specific range (around + 2%/min). The HR did not follow the increase in acoustic tempo when the rate of the increase in the acoustic tempo exceeded 3% per minute. These results suggest that the effect of the sympatho-respiratory coupling underlying the HR elevation caused by a high acoustic tempo depends on the basal HR, and the strength and the temporal dynamics of the tempo.

  18. Heart rate responses induced by acoustic tempo and its interaction with basal heart rate

    PubMed Central

    Watanabe, Ken; Ooishi, Yuuki; Kashino, Makio

    2017-01-01

    Many studies have revealed the influences of music on the autonomic nervous system (ANS). Since previous studies focused on the effects of acoustic tempo on the ANS, and humans have their own physiological oscillations such as the heart rate (HR), the effects of acoustic tempo might depend on the HR. Here we show the relationship between HR elevation induced by acoustic tempo and individual basal HR. Since high tempo-induced HR elevation requires fast respiration, which is based on sympatho-respiratory coupling, we controlled the participants’ respiration at a faster rate (20 CPM) than usual (15 CPM). We found that sound stimuli with a faster tempo than the individual basal HR increased the HR. However, the HR increased following a gradual increase in the acoustic tempo only when the extent of the gradual increase in tempo was within a specific range (around + 2%/min). The HR did not follow the increase in acoustic tempo when the rate of the increase in the acoustic tempo exceeded 3% per minute. These results suggest that the effect of the sympatho-respiratory coupling underlying the HR elevation caused by a high acoustic tempo depends on the basal HR, and the strength and the temporal dynamics of the tempo. PMID:28266647

  19. Signal processing methodologies for an acoustic fetal heart rate monitor

    NASA Technical Reports Server (NTRS)

    Pretlow, Robert A., III; Stoughton, John W.

    1992-01-01

    Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones within a noise-contaminated signal from a passive acoustic sensor. A linear predictor algorithm is utilized for detection of the heart tone event and additional processing derives heart rate. The linear predictor is adaptively 'trained' in a least mean square error sense on generic fetal heart tones recorded from patients. A real time monitor system is described which outputs to a strip chart recorder for plotting the time history of the fetal heart rate. The system is validated in the context of the fetal nonstress test. Comparisons are made with ultrasonic nonstress tests on a series of patients. Comparative data provides favorable indications of the feasibility of the acoustic monitor for clinical use.

  20. [Typical spontaneous changes in heart rate in pheochromocytoma].

    PubMed

    Bramann, H U; Zidek, W; Vetter, H; Grosse-Heitmeyer, W

    1985-01-01

    Investigations in 13 hospitalized patients with pheochromocytomata showed peculiar characteristics of heart rate variation at rest, when compared with normals. All patients were given alpha- and beta-sympatholytic drugs. In one case alpha-methyl-Tyrosine caused I-II degree AV blocks and a stable high frequency sinus rate without physiological variations. Resting heart rate in pheochromocytoma varied interindividually from 55-105/min, in the absence of clinical attacks of the underlying disease. The frequency profile was characterized in 12 patients by sudden and inadequate rises of heart rate (200%) of short duration, which were often recorded within 20 seconds of the onset of muscular activity. A similar but less pronounced heart rate modulation was found 1-2 weeks after operation in 3 cases. Our observations indicate that the heart rate profile described may be a sensitive parameter of dysfunction of the autonomous nervous system in pheochromocytoma. Whether the heart rate characteristics are of diagnostic value has to be assessed by further studies.

  1. Arduino-based noise robust online heart-rate detection.

    PubMed

    Das, Sangita; Pal, Saurabh; Mitra, Madhuchhanda

    2017-04-01

    This paper introduces a noise robust real time heart rate detection system from electrocardiogram (ECG) data. An online data acquisition system is developed to collect ECG signals from human subjects. Heart rate is detected using window-based autocorrelation peak localisation technique. A low-cost Arduino UNO board is used to implement the complete automated process. The performance of the system is compared with PC-based heart rate detection technique. Accuracy of the system is validated through simulated noisy ECG data with various levels of signal to noise ratio (SNR). The mean percentage error of detected heart rate is found to be 0.72% for the noisy database with five different noise levels.

  2. Heart rate measurement as a tool to quantify sedentary behavior.

    PubMed

    Åkerberg, Anna; Koshmak, Gregory; Johansson, Anders; Lindén, Maria

    2015-01-01

    Sedentary work is very common today. The aim of this pilot study was to attempt to differentiate between typical work situations and to investigate the possibility to break sedentary behavior, based on physiological measurement among office workers. Ten test persons used one heart rate based activity monitor (Linkura), one pulse oximeter device (Wrist) and one movement based activity wristband (Fitbit Flex), in different working situations. The results showed that both heart rate devices, Linkura and Wrist, were able to detect differences in heart rate between the different working situations (resting, sitting, standing, slow walk and medium fast walk). The movement based device, Fitbit Flex, was only able to separate differences in steps between slow walk and medium fast walk. It can be concluded that heart rate measurement is a promising tool for quantifying and separating different working situations, such as sitting, standing and walking.

  3. Criticality and Universality in Healthy Heart Rate Dynamics

    NASA Astrophysics Data System (ADS)

    Struzik, Zbigniew R.; Kiyono, Ken; Hayano, Junichiro; Sakata, Seiichiro; Kwak, Shin; Yamamoto, Yoshiharu

    2005-08-01

    Methodologies originally developed in the field of statistical physics of complex phenomena have been proven to provide new insights into the modeling, description and understanding of the human heart rate regulatory system. Recent studies have shown the heart rate control system to maintain universality properties characteristic of physical systems exhibiting far-from-equilibrium, critical state-like dynamics. Simultaneously, heart rate regulation has been shown to display correlation properties of antagonist dynamics involving antagonist actors, pertinent to some far-from-equilibrium systems. We discuss the range of validity and breakdown scenarios of the universal properties in heart rate regulation leading to the diagnostic capability and also to new challenges for both analysis methods and up-to-date simulation models.

  4. Heart Rate Response and Lactic Acid Concentration in Squash Players.

    ERIC Educational Resources Information Center

    Beaudin, Paula; And Others

    1978-01-01

    It was concluded that playing squash is an activity that results in heart rate responses of sufficient intensity to elicit aerobic training effects without producing high lactic acid concentration in the blood. (MM)

  5. Method of Discriminant Gravity Tolerance using Heart Rate Variability

    NASA Astrophysics Data System (ADS)

    Yoshida, Yutaka; Yokoyama, Kiyoko; Takada, Hiroki; Iwase, Satoshi

    When returning on the earth by the space flight, the space deconditioning may be developed. As this countermeasure, the artificial gravity load device using the centrifuge is proposed in the space station. But the gravity load might cause the faint, and safe gravity load is uncertainty. We proposed that discriminate strength of gravity tolerance using heart rate variability time series. Step function was inputted to AR model estimated from heart rate variability time series during rest or under light gravity load, and strength of the gravity tolerance was discriminated by the step response function. On the result, discriminant accuracy was 87.5% by using heart rate variability time series when gravity load of 1.0 G was added to the human lying on the supine. Therefore, possibility of discriminant of gravity tolerance was obtained by using heart rate variability time series when sympathetic hyperactivity. Discriminant of the gravity tolerance is expected before countermeasure of space deconditioning is executed.

  6. Heart Rate at Hospital Discharge in Patients With Heart Failure Is Associated With Mortality and Rehospitalization

    PubMed Central

    Laskey, Warren K.; Alomari, Ihab; Cox, Margueritte; Schulte, Phillip J.; Zhao, Xin; Hernandez, Adrian F.; Heidenreich, Paul A.; Eapen, Zubin J.; Yancy, Clyde; Bhatt, Deepak L.; Fonarow, Gregg C.

    2015-01-01

    Background Whether heart rate upon discharge following hospitalization for heart failure is associated with long‐term adverse outcomes and whether this association differs between patients with sinus rhythm (SR) and atrial fibrillation (AF) have not been well studied. Methods and Results We conducted a retrospective cohort study from clinical registry data linked to Medicare claims for 46 217 patients participating in Get With The Guidelines®–Heart Failure. Cox proportional‐hazards models were used to estimate the association between discharge heart rate and all‐cause mortality, all‐cause readmission, and the composite outcome of mortality/readmission through 1 year. For SR and AF patients with heart rate ≥75, the association between heart rate and mortality (expressed as hazard ratio [HR] per 10 beats‐per‐minute increment) was significant at 0 to 30 days (SR: HR 1.30, 95% CI 1.22 to 1.39; AF: HR 1.23, 95% CI 1.16 to 1.29) and 31 to 365 days (SR: HR 1.15, 95% CI 1.12 to 1.20; AF: HR 1.05, 95% CI 1.01 to 1.08). Similar associations between heart rate and all‐cause readmission and the composite outcome were obtained for SR and AF patients from 0 to 30 days but only in the composite outcome for SR patients over the longer term. The HR from 0 to 30 days exceeded that from 31 to 365 days for both SR and AF patients. At heart rates <75, an association was significant for mortality only for both SR and AF patients. Conclusions Among older patients hospitalized with heart failure, higher discharge heart rate was associated with increased risks of death and rehospitalization, with higher risk in the first 30 days and for SR compared with AF. PMID:25904590

  7. Accuracy of Heart Rate Watches: Implications for Weight Management

    PubMed Central

    2016-01-01

    Background Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established. Aim To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha) to measure heart rate and energy expenditure at rest and during exercise. Methods Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years) completed ~1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate) and indirect calorimetry (energy expenditure). Results None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67–0.95 [0.35 to 0.98]) and weak to strong for energy expenditure (0.16–0.86 [-0.25 to 0.95]). All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1–9%) but greater for energy expenditure (9–43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices. Conclusion These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss. PMID:27232714

  8. Idiosyncratic heart rate response in men during sexual arousal.

    PubMed

    Rowland, David L; Crawford, Sara B

    2011-05-01

    Heart rate, sensitive to sympathetic activation, is known to change during sexual arousal and therefore may be a useful tool for investigating psychosomatic differences between sexually functional and dysfunctional men. However, heart rate during arousal also tends to be highly variable across individual men, making its predictability based on group patterns relatively poor. We wanted to determine whether individual men show idiosyncratic heart rate patterns during sexual arousal, that is, whether they exhibit consistent patterns across similar (though not identical) stimulus situations. Agreement between heart rates under the two conditions, visual sexual stimulation (VSS) and VSS + vibrotactile (VIB), was assessed using the concordance correlation coefficient (CCC).   Thirty-eight men, 25 of whom were diagnosed with premature ejaculation (PE), were monitored for penile response and heart rate under two similar (though not identical) conditions: a 9-minute erotic video (VSS), then a 9-minute erotic video combined with vibrotactile penile stimulation (VSS + VIB). CCC for men with PE was 0.65; for the sexually functional comparison group, CCC was 0.82. For both groups combined, CCC was 0.71. For all groupings, the CCC was relatively high, indicating agreement in heart rate from one session to the next within individual men. Despite high intersubject variation in heart rate patterns, individual men show signature heart rates across similar sexual stimulus sessions. Such stereotypy helps explain previous inconsistent findings and may also serve as a marker for the effectiveness of treatments designed to improve ejaculatory control in men with PE. © 2011 International Society for Sexual Medicine.

  9. Assessment of anxiety using heart rate nonlinear dynamics

    NASA Astrophysics Data System (ADS)

    Thayer, Julian F.; Friedman, Bruce H.

    1993-11-01

    Various anxiety states have been linked with disorders of the autonomic nervous system. These autonomic disorders may be revealed by analysis of physiological time series such as the heart rate interbeat interval series. The present paper reports a general model of biological system functioning and related assessment indices based on recent nonlinear dynamical systems approaches. In particular, two experimental studies are reported which suggest the utility of heart rate nonlinear dynamics in the assessment of anxiety.

  10. Resting Heart Rate and Aortic Stiffness in Normotensive Adults.

    PubMed

    Logan, Jeongok G; Kim, Suk-Sun

    2016-11-01

    Large-artery stiffness is an independent predictor of cardiovascular disease (CVD), and carotid-femoral pulse wave velocity (cfPWV) is considered the gold standard measure of arterial stiffness. A resting heart rate is an easily measured vital sign that is also associated with CVD morbidity and mortality. Previous studies have reported the significant relationship of a resting heart rate with arterial stiffness as measured by cfPWV only in hypertensive subjects; their relationship in nonhypertensive subjects remains unknown. The present study, therefore, examined their relationship in normotensive subjects. In 102 healthy Korean Americans between ages 20 and 60 years, their resting heart rate was measured by an automated blood pressure measuring device after a 10 minute rest in the supine position. Arterial stiffness was measured by cfPWV using the SphygmoCor device. The mean resting heart rate of participants (mean age, 39.64 years; 59% women) was 61.91 bpm (standard deviation [SD], 9.62 bpm) and mean the cfPWV was 6.99 (SD, 1.14) m/s. A multiple regression analysis showed that a resting heart rate is a significant predictor of cfPWV after controlling for age, body mass index, and mean arterial pressure. For one bpm increase of resting heart rate, cfPWV increased approximately 0.02 m/s. Our results suggest that a higher resting heart rate is independently associated with increased arterial stiffness as measured by cfPWV in normotensive adults. Arterial stiffness may explain the prognostic role of an individual's heart rate in cardiovascular morbidity and mortality.

  11. Resting Heart Rate and Aortic Stiffness in Normotensive Adults

    PubMed Central

    Logan, Jeongok G.

    2016-01-01

    Background and Objectives Large-artery stiffness is an independent predictor of cardiovascular disease (CVD), and carotid-femoral pulse wave velocity (cfPWV) is considered the gold standard measure of arterial stiffness. A resting heart rate is an easily measured vital sign that is also associated with CVD morbidity and mortality. Previous studies have reported the significant relationship of a resting heart rate with arterial stiffness as measured by cfPWV only in hypertensive subjects; their relationship in nonhypertensive subjects remains unknown. The present study, therefore, examined their relationship in normotensive subjects. Subjects and Methods In 102 healthy Korean Americans between ages 20 and 60 years, their resting heart rate was measured by an automated blood pressure measuring device after a 10 minute rest in the supine position. Arterial stiffness was measured by cfPWV using the SphygmoCor device. Results The mean resting heart rate of participants (mean age, 39.64 years; 59% women) was 61.91 bpm (standard deviation [SD], 9.62 bpm) and mean the cfPWV was 6.99 (SD, 1.14) m/s. A multiple regression analysis showed that a resting heart rate is a significant predictor of cfPWV after controlling for age, body mass index, and mean arterial pressure. For one bpm increase of resting heart rate, cfPWV increased approximately 0.02 m/s. Conclusion Our results suggest that a higher resting heart rate is independently associated with increased arterial stiffness as measured by cfPWV in normotensive adults. Arterial stiffness may explain the prognostic role of an individual's heart rate in cardiovascular morbidity and mortality. PMID:27826343

  12. Heart rate variability in natural time and 1/f "noise"

    NASA Astrophysics Data System (ADS)

    Sarlis, N. V.; Skordas, E. S.; Varotsos, P. A.

    2009-07-01

    Several studies have shown that heart rate fluctuations exhibit the ubiquitous 1/f behavior which is altered in desease. Furthermore, the analysis of electrocardiograms in natural time reveals that important malfunctions in the complex system of the human heart can be identified. Here, we present a simple evolution model in natural time that exhibits the 1/fa behavior with a close to unity. The results of this model are consistent with a progressive modification of heart rate variability in healthy children and adolescents. The model results in complexity measures that separate healthy dynamics from patients as well as from sudden cardiac death individuals.

  13. Short-term heart rate variability in young athletes.

    PubMed

    Aubert, A E; Beckers, F; Ramaekers, D

    2001-01-01

    The purpose of this study was to determine whether the type of training in a young population differentiates heart rate variability parameters between athlete groups and sedentary subjects. The effect of different types of physical training on heart rate variability was evaluated in 10 aerobic trained athletes, in 7 anaerobic trained athletes, in 7 rugby players (mixed type training) and in 10 sedentary control subjects. All groups were age matched (18-34 years). Electrocardiogram tracings were recorded digitally in the supine position and standing position. Measures of heart rate variability were obtained, from both time- and frequency analysis of 10 min resting heart rate. After these tests, blood pressure was measured using an automatic inflation cuff. Resting heart rate was lower in aerobic and mixed type athletes compared to controls. Only aerobic athletes had evidence of increased vagal activity in the time domain compared with control subjects (increased SDNN supine, increased rMSSD supine and standing and pNN50 standing). In the frequency domain, aerobic athletes presented with both higher low-frequency and high-frequency power in the standing position and low-frequency power in the supine position compared to controls. It can be concluded that heart rate variability is affected by chronic exercise, especially in endurance trained athletes. This infers that especially aerobic exercising can have beneficial effects on the cardiovascular risk profile.

  14. Probability of detection of clinical seizures using heart rate changes.

    PubMed

    Osorio, Ivan; Manly, B F J

    2015-08-01

    Heart rate-based seizure detection is a viable complement or alternative to ECoG/EEG. This study investigates the role of various biological factors on the probability of clinical seizure detection using heart rate. Regression models were applied to 266 clinical seizures recorded from 72 subjects to investigate if factors such as age, gender, years with epilepsy, etiology, seizure site origin, seizure class, and data collection centers, among others, shape the probability of EKG-based seizure detection. Clinical seizure detection probability based on heart rate changes, is significantly (p<0.001) shaped by patients' age and gender, seizure class, and years with epilepsy. The probability of detecting clinical seizures (>0.8 in the majority of subjects) using heart rate is highest for complex partial seizures, increases with a patient's years with epilepsy, is lower for females than for males and is unrelated to the side of hemisphere origin. Clinical seizure detection probability using heart rate is multi-factorially dependent and sufficiently high (>0.8) in most cases to be clinically useful. Knowledge of the role that these factors play in shaping said probability will enhance its applicability and usefulness. Heart rate is a reliable and practical signal for extra-cerebral detection of clinical seizures originating from or spreading to central autonomic network structures. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  15. [The exercise training restores the heart rate variability in heart failure patients. A systematic review].

    PubMed

    Segovia, Victoria; Manterola, Carlos; González, Marcelo; Rodríguez-Núñez, Iván

    2017-01-05

    Cardiovascular diseases are an important cause of morbidity and mortality in the general population. In this sense the autonomic imbalance is the cornerstone of the physiopathology underlying the development of these diseases. The aim of this study was to determine the efficacy of exercise training on heart rate variability (HRV) in adult patients with chronic heart failure.

  16. Heart rate, heart rate variability and behaviour of horses during air transport.

    PubMed

    Munsters, C C B M; de Gooijer, J-W; van den Broek, J; van Oldruitenborgh-Oosterbaan, M M Sloet

    2013-01-05

    Heart rate (HR), HR variability (HRV) and behaviour score (BS) of nine horses were evaluated during an eight-hour air transport between The Netherlands and New York. HR and HRV parameters were calculated every five minutes during the air transport. Compared with transit (40±3), mean HRs were higher during loading into the jet stall (67±21, P<0.001), loading into the aircraft (47±6, P=0.011), taxiing (50±8, P=0.001), and during periods of in-flight turbulence (46±7, P=0.017). During the flight, individual horses showed differences in mean HR (P=0.005) and peak HR (P<0.001). By contrast with HR data, HRV data did not differ between stages or horses. BS was highest during turbulence (3.2±0.4). However, behaviour did not always correspond with HR measurements: the least responsive horse had the highest HR. Loading into the jet stall caused the highest increase in HR and was considered the most stressful event. During transit, HR was generally comparable with resting rates. Previous studies have shown that loading and transporting by road caused more elevation in HR than during loading and transporting by air. HRV data were not found to be useful, and caution is needed when interpreting HRV data. Not every horse exhibited stress through visible (evasive) behaviour, and HR measurements may provide an additional tool to assess stress in horses.

  17. Nicotine-induced perturbations on heart rate, body temperature and locomotor activity daily rhythms in rats.

    PubMed

    Pelissier, A L; Gantenbein, M; Bruguerolle, B

    1998-08-01

    The aim of this study was to evaluate the influence of nicotine on the daily rhythms of heart rate, body temperature and locomotor activity in unrestrained rats by use of implanted radiotelemetry transmitters. The study was divided into three seven-day periods: a control period, a treatment period and a recovery period. The control period was used for baseline measurement of heart rate, body temperature and locomotor activity. During the treatment period three rats received nicotine (1 mg kg(-1), s.c.) at 0900 h. Three rats received saline under the same experimental conditions. Heart rate, body temperature and locomotor activity were continuously monitored and plotted every 10 min. During the three periods a power spectrum analysis was used to determine the dominant period of rhythmicity. If daily rhythms of heart rate, body temperature and locomotor activity were detected, the characteristics of these rhythms, i.e. the mesors, amplitudes and acrophases, were determined by cosinor analysis, expressed as means +/- s.e.m. and compared by analysis of variance. Nicotine did not suppress daily rhythmicity but induced decreases of amplitudes and phase-advances of acrophases for heart rate, body temperature and locomotor activity. These perturbations might result from the effects of nicotine on the suprachiasmatic nucleus, the hypothalamic clock that co-ordinates biological rhythms.

  18. Association of heart rate at hospital discharge with mortality and hospitalizations in patients with heart failure.

    PubMed

    Habal, Marlena V; Liu, Peter P; Austin, Peter C; Ross, Heather J; Newton, Gary E; Wang, Xuesong; Tu, Jack V; Lee, Douglas S

    2014-01-01

    Heart failure (HF) is associated with a high burden of morbidity and mortality. Hospital discharge is an opportunity for identification of modifiable prognostic factors in the transition to chronic HF. We examined the association of discharge heart rate with 30-day and 1-year mortality and hospitalization outcomes in a cohort of 9097 patients with HF discharged from hospital. Discharge heart rate was categorized into predefined groups: 40 to 60 (n=1333), 61 to 70 (n=2170), 71 to 80 (n=2631), 81 to 90 (n=1700), and >90 bpm (n=1263). There was a significant increase in all-cause 30-day mortality with adjusted odds ratios of 1.59 (95% confidence interval [CI], 1.18-2.14; P=0.003) for discharge heart rates 81 to 90 bpm and 1.56 (95% CI, 1.13-2.16; P=0.007) for heart rates>90 bpm when compared with the reference group (heart rates, 61-70 bpm). Cardiovascular death risk at 30 days was also higher with adjusted odds ratio 1.59 (discharge heart rates, 81-90 bpm; 95% CI, 1.09-2.33; P=0.017) and 1.65 (discharge heart rates, >90 bpm; 95% CI, 1.09-2.48; P=0.017). One-year all-cause mortality (adjusted odds ratio, 1.41; 95% CI, 1.16-1.72; P<0.001) and cardiovascular death (adjusted odds ratio, 1.47; 95% CI, 1.12-1.92; P=0.005) were higher with discharge heart rates>90 bpm when compared with the reference group (heart rates, 40-60 bpm). Readmissions for HF (adjusted hazard ratio, 1.26; 95% CI, 1.04-1.54; P=0.021) and cardiovascular disease (adjusted hazard ratio, 1.29; 95% CI, 1.08-1.54; P=0.004) within 30 days were also higher with discharge heart rates>90 bpm. Higher discharge heart rates were associated with greater risk of all-cause and cardiovascular mortality≤1-year follow-up and an elevated risk of 30-day readmission for HF and cardiovascular disease.

  19. 1/f scaling in heart rate requires antagonistic autonomic control

    NASA Astrophysics Data System (ADS)

    Struzik, Zbigniew R.; Hayano, Junichiro; Sakata, Seiichiro; Kwak, Shin; Yamamoto, Yoshiharu

    2004-11-01

    We present systematic evidence for the origins of 1/f -type temporal scaling in human heart rate. The heart rate is regulated by the activity of two branches of the autonomic nervous system: the parasympathetic (PNS) and the sympathetic (SNS) nervous systems. We examine alterations in the scaling property when the balance between PNS and SNS activity is modified, and find that the relative PNS suppression by congestive heart failure results in a substantial increase in the Hurst exponent H towards random-walk scaling 1/f2 and a similar breakdown is observed with relative SNS suppression by primary autonomic failure. These results suggest that 1/f scaling in heart rate requires the intricate balance between the antagonistic activity of PNS and SNS.

  20. Heart rate increases linearly in response to acute isovolemic anemia.

    PubMed

    Weiskopf, Richard B; Feiner, John; Hopf, Harriet; Viele, Maurene K; Watson, Jessica J; Lieberman, Jeremy; Kelley, Scott; Toy, Pearl

    2003-02-01

    The cardiovascular response to acute isovolemic anemia in humans is thought to differ from that of other species. Studies of anesthetized humans have found either no change or a decreased heart rate. A previous study showed that in 32 healthy unmedicated humans, heart rate increased during acute isovolemic anemia. The hypothesis that heart rate in humans increases in response to acute isovolemic anemia and that the increase is affected by gender was tested. Acute isovolemic anemia to a Hb concentration of approximately 5 g per dL in 95 unmedicated healthy humans was produced by simultaneous withdrawal of blood and IV replacement with 5-percent HSA and autologous platelet-rich plasma. The relationship between heart rate and Hb concentration was examined using a mixed-effects linear regression model that allowed each person to have a fitted line with its own slope and intercept. Cubic and quadratic terms were added to determine if these improved the goodness of fit. The effect of gender was tested by including it and its interactions with Hb in the mixed model. The relationship between heart rate and Hb concentration was linear (p < 0.001) and consistent among the population studied: heart rate = 116.0-4.0 [Hb] (slope 95% CI: -4.2 to -3.8 beats/min/g Hb). Adding a cubic or quadratic term did not significantly improve the goodness of fit of the mathematical expression to the data, confirming the linear nature of the relationship between heart rate and Hb concentration. For women, the slope of the heart rate response was significantly greater than it was for males (difference +/- SE: 0.70 +/- 0.23, p < 0.005). In 95 unmedicated, healthy humans, heart rate was a linear function of Hb during acute isovolemic anemia. Females had a significantly greater slope of increase in heart rate with decreasing Hb concentration than did males. The relationship is consistent among individuals, is similar to that reported for conscious dogs, and differs from that found previously in

  1. Discharge heart rate and mortality after acute myocardial infarction.

    PubMed

    Seronde, Marie France; Geha, Raghed; Puymirat, Etienne; Chaib, Aurès; Simon, Tabassome; Berard, Laurence; Drouet, Elodie; Bataille, Vincent; Danchin, Nicolas; Schiele, François

    2014-10-01

    We aimed to describe the determinants of discharge heart rate in acute coronary syndrome patients and assess the impact of discharge heart rate on 5-year mortality in hospital survivors. French Registry of Acute ST-Elevation or non-ST-elevation Myocardial Infarction (FAST-MI) 2005 is a nationwide French registry that included all consecutive patients with acute myocardial infarction over 1 month in 223 institutions in 2005. Discharge heart rate was recorded in 3079 patients discharged alive; all had 5-year follow-up. Logistic regression was used to detect predictors of high heart rate at discharge. Cox's proportional hazards model was used to assess the hazard ratio for mortality at 5 years. Heart rate was categorized into 4 groups by quartiles (<60, 61-67, 68-75, >75 beats per minute). High heart rate was defined as ≥75 beats per minute. Landmark analysis was performed at 1 year. Independent predictors of heart rate ≥75 beats per minute at discharge were female sex, ST-segment elevation myocardial infarction, diabetes, chronic obstructive pulmonary disease, bleeding/transfusion during hospitalization, left ventricular dysfunction, renal dysfunction, and prescription (type, but not dose category) of beta-blockers at discharge. Discharge heart rate was significantly related to mortality at 1 year (hazard ratio 1.13; 95% confidence interval, 1.03-1.24 per 10 beats per minute, P = .02); this was confirmed by landmark analysis, with a 39% increase (hazard ratio 1.39; 95% confidence interval 1.05-1.84) in the risk of 1-year death for discharge heart rate ≥75 beats per minute vs <75 beats per minute. This relationship was no longer significant between 2 and 5 years. After acute myocardial infarction, patients discharged with high heart rate (≥75 beats per minute) are at higher risk of death during the first year, but not later, irrespective of beta-blocker use. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Assessing positive emotional states in dogs using heart rate and heart rate variability.

    PubMed

    Zupan, Manja; Buskas, Julia; Altimiras, Jordi; Keeling, Linda J

    2016-03-01

    Since most animal species have been recognized as sentient beings, emotional state may be a good indicator of welfare in animals. The goal of this study was to manipulate the environment of nine beagle research dogs to highlight physiological responses indicative of different emotional experiences. Stimuli were selected to be a more or a less positive food (meatball or food pellet) or social reward (familiar person or less familiar person). That all the stimuli were positive and of different reward value was confirmed in a runway motivation test. Dogs were tested individually while standing facing a display theatre where the different stimuli could be shown by lifting a shutter. The dogs approached and remained voluntarily in the test system. They were tested in four sessions (of 20s each) for each of the four stimuli. A test session consisted of four presentation phases (1st exposure to stimulus, post exposure, 2nd exposure, and access to reward). Heart rate (HR) and heart rate variability (HRV) responses were recorded during testing in the experimental room and also when lying resting in a quiet familiar room. A new method of 'stitching' short periods of HRV data together was used in the analysis. When testing different stimuli, no significant differences were observed in HR and LF:HF ratio (relative power in low frequency (LF) and the high-frequency (HF) range), implying that the sympathetic tone was activated similarly for all the stimuli and may suggest that dogs were in a state of positive arousal. A decrease of HF was associated with the meatball stimulus compared to the food pellet and the reward phase (interacting with the person or eating the food) was associated with a decrease in HF and RMSSD (root mean square of successive differences of inter-beat intervals) compared to the preceding phase (looking at the person or food). This suggests that parasympathetic deactivation is associated with a more positive emotional state in the dog. A similar reduction

  3. Left ventricular performance of the athletic heart during upright exercise: a heart rate-controlled study.

    PubMed

    Rubal, B J; Moody, J M; Damore, S; Bunker, S R; Diaz, N M

    1986-02-01

    This study compares the left ventricular performance of chronically conditioned pentathletes (N = 10) with less-conditioned subjects (N = 10) during dynamic upright exercise. The pentathletes were found to have a superior treadmill performance [24 +/- 4 vs 17 +/- 2 min (SD), P less than 0.01], reduced resting heart rate (41 +/- 13 vs 62 +/- 6 bpm, P less than 0.01), and increased left ventricular mass (254 +/- 85 vs 179 +/- 35 g, P less than 0.05) compared to the control group. Radionuclide ventriculography and heart rate controlled-bicycle ergometry were employed to examine changes in left ventricular ejection fraction, end-diastolic volume, end-systolic volume, and stroke volume. Heart rate was controlled by adjusting the resistance of the ergometer until stable heart rates of 90, 110, 130, and 150 bpm were achieved. Following heart rate stabilization, 99mTc images were acquired during 3-min stages at each target heart rate level. In the pentathletes, left ventricular ejection fraction, end-diastolic volume, and stroke volume increased (P less than 0.01) during exercise, and end-systolic volume tended to decrease. No difference was noted in left ventricular ejection fraction between groups when heart rates were matched. However, the exercise-induced changes in end-diastolic volume and stroke volume were greater (P less than 0.01) in the pentathletes. In conclusion, the athletes studied relied on the same mechanism as the less-conditioned subjects for improving pump performance during exercise stress, but the athletes' ability to mobilize a greater end-diastolic volume accounts for their larger stroke output during each stage of heart rate-matched exercise.

  4. Heart rate variability and heart rate turbulence in mild-to-moderate aortic stenosis.

    PubMed

    Arslan, Ugur; Ozdemir, Murat; Kocaman, Sinan Altan; Balcioglu, Serhat; Cemri, Mustafa; Cengel, Atiye

    2008-12-01

    To study heart rate (HR) variability and HR turbulence parameters in mild-to-moderate aortic stenosis (AS) and to disclose whether any relationship exists between these parameters and echocardiographic findings. Forty-three asymptomatic patients with mild-to-moderate AS (AS group) were studied. Echocardiographic parameters and HR variability and HR turbulence indices obtained over 24 Holter ECG recordings were compared with those of an age and sex matched control population free of cardiovascular disease. Correlation between echocardiographic findings and HR variability and HR turbulence indices was also studied in the AS group. All HR variability parameters except mean RR interval, RMSSD, and pNN50 and one HR turbulence parameter, turbulence onset, were significantly disturbed in the AS group. Echocardiographic findings of diastolic dysfunction had significant correlations with HR variability and HR turbulence parameters in AS patients. Symphatovagal imbalance as shown by disturbed HR variability and HR turbulence parameters was demonstrated for the first time in patients with mild-to-moderate AS. This imbalance, which was shown to be correlated with echocardiographic findings of diastolic dysfunction, may lead to arrhythmic complications in this seemingly low-risk patient population.

  5. Sleep-Wakefulness Determinations from Heart Rate Data.

    DTIC Science & Technology

    1978-08-01

    desirable yet unattained reality . -Por the past decade, a number of projects have been con- ducted in the Biomedical Engineering Program here at the...average, the range of hea.4 -ate is lower during sleep than during waking. virtually all researchers agre 1, ,1,1, 5,5,63 tatthe variability of heart...7 7. 7. 1..-. 13. Carli, G.: Blood pressure and heart rate in the rabbit during animal hypnosis . Electroencephalog. Clin. Neurophysiol., 37:231-237

  6. Long-range dependencies in heart rate signals—revisited

    NASA Astrophysics Data System (ADS)

    Makowiec, Danuta; Gałaşka, Rafał; Dudkowska, Aleksandra; Rynkiewicz, Andrzej; Zwierz, Marcin

    2006-09-01

    The arguments are given that local exponents obtained in multifractal analysis by two methods: wavelet transform modulus maxima (WTMM) and multifractal detrended fluctuation analysis (MDFA) allow to separate statistically hearts of healthy people and subjects suffering from reduced left ventricle systolic function (NYHA I-III class). Proposed indices of fractality suggest that a signal of human heart rate is a mixture of two processes: monofractal and multifractal ones.

  7. Quantification of fetal heart rate regularity using symbolic dynamics.

    PubMed

    van Leeuwen, P; Cysarz, D; Lange, S; Geue, D; Groenemeyer, D

    2007-03-01

    Fetal heart rate complexity was examined on the basis of RR interval time series obtained in the second and third trimester of pregnancy. In each fetal RR interval time series, short term beat-to-beat heart rate changes were coded in 8 bit binary sequences. Redundancies of the 2(8) different binary patterns were reduced by two different procedures. The complexity of these sequences was quantified using the approximate entropy (ApEn), resulting in discrete ApEn values which were used for classifying the sequences into 17 pattern sets. Also, the sequences were grouped into 20 pattern classes with respect to identity after rotation or inversion of the binary value. There was a specific, nonuniform distribution of the sequences in the pattern sets and this differed from the distribution found in surrogate data. In the course of gestation, the number of sequences increased in seven pattern sets, decreased in four and remained unchanged in six. Sequences that occurred less often over time, both regular and irregular, were characterized by patterns reflecting frequent beat-to-beat reversals in heart rate. They were also predominant in the surrogate data, suggesting that these patterns are associated with stochastic heart beat trains. Sequences that occurred more frequently over time were relatively rare in the surrogate data. Some of these sequences had a high degree of regularity and corresponded to prolonged heart rate accelerations or decelerations which may be associated with directed fetal activity or movement or baroreflex activity. Application of the pattern classes revealed that those sequences with a high degree of irregularity correspond to heart rate patterns resulting from complex physiological activity such as fetal breathing movements. The results suggest that the development of the autonomic nervous system and the emergence of fetal behavioral states lead to increases in not only irregular but also regular heart rate patterns. Using symbolic dynamics to

  8. Quantification of fetal heart rate regularity using symbolic dynamics

    NASA Astrophysics Data System (ADS)

    van Leeuwen, P.; Cysarz, D.; Lange, S.; Geue, D.; Groenemeyer, D.

    2007-03-01

    Fetal heart rate complexity was examined on the basis of RR interval time series obtained in the second and third trimester of pregnancy. In each fetal RR interval time series, short term beat-to-beat heart rate changes were coded in 8bit binary sequences. Redundancies of the 28 different binary patterns were reduced by two different procedures. The complexity of these sequences was quantified using the approximate entropy (ApEn), resulting in discrete ApEn values which were used for classifying the sequences into 17 pattern sets. Also, the sequences were grouped into 20 pattern classes with respect to identity after rotation or inversion of the binary value. There was a specific, nonuniform distribution of the sequences in the pattern sets and this differed from the distribution found in surrogate data. In the course of gestation, the number of sequences increased in seven pattern sets, decreased in four and remained unchanged in six. Sequences that occurred less often over time, both regular and irregular, were characterized by patterns reflecting frequent beat-to-beat reversals in heart rate. They were also predominant in the surrogate data, suggesting that these patterns are associated with stochastic heart beat trains. Sequences that occurred more frequently over time were relatively rare in the surrogate data. Some of these sequences had a high degree of regularity and corresponded to prolonged heart rate accelerations or decelerations which may be associated with directed fetal activity or movement or baroreflex activity. Application of the pattern classes revealed that those sequences with a high degree of irregularity correspond to heart rate patterns resulting from complex physiological activity such as fetal breathing movements. The results suggest that the development of the autonomic nervous system and the emergence of fetal behavioral states lead to increases in not only irregular but also regular heart rate patterns. Using symbolic dynamics to

  9. Daily stride rate activity and heart rate response in children with cerebral palsy.

    PubMed

    Balemans, Astrid C J; van Wely, Leontien; Middelweerd, Anouk; van den Noort, Josien C; Becher, Jules G; Dallmeijer, Annet J

    2014-01-01

    To compare daily stride rate activity, daily exercise intensity, and heart rate intensity of stride rate in children with cerebral palsy with that of typically developing children. Forty-three children with cerebral palsy, walking without (Gross Motor Function Classification System (GMFCS) I and II) or with (GMFCS III) an aid and 27 typically developing children (age range 7-14 years) wore a StepWatch™ activity monitor and a heart rate monitor. Time spent and mean heart rate reserve at each stride rate activity level and time spent in each mean heart rate reserve zone was compared. Daily stride rate activity was lower in children with cerebral palsy (39%, 49% and 79% in GMFCS I, II and III, respectively) compared with typically developing children (p < 0.05), while there were no differences in time spent at different mean heart rate reserve zones. Mean heart rate reserve at all stride rate activity levels was not different between typically developing children, GMFCS I and II, while mean heart rate reserve was higher for GFMCS III at stride rates < 30 strides/min (p < 0.05). Stride rate activity levels reflect the effort of walking, in children with cerebral palsy who are walking without aids, similar to that of typically developing, whereas children with cerebral palsy using walking aids show higher effort of walking. Despite a lower stride rate activity in cerebral palsy, daily exercise intensity seems comparable, indicating that the StepWatch™ monitor and the heart rate monitor measure different aspects of physical activity.

  10. Bicycling for transportation improves heart rate variability in young adults.

    PubMed

    Bueno, Henrique M; Sartori, Michelle; Macedo, Hidalina R; Moraes-Silva, Ivana C; Aletti, Federico; Irigoyen, Maria C; DE Angelis, Kátia

    2017-03-01

    Physical activity has been considered an effective method to treat and prevent cardiovascular and metabolic disease. An important mechanism benefited by exercise training is the cardiovascular autonomic control, often impaired in cardiometabolic disease. Cycling used as a daily means of transport can be considered an interesting alternative to regular physical exercise practice. Therefore, this study intent to compare metabolic, hemodynamic and cardiovascular autonomic profiles of young adult men who were used to cycle for transportation (CT) with those considered insufficiently actives (IA). Body composition, blood pressure, glucose, total cholesterol and triglycerides were evaluated at rest. Heart rate variability was analyzed in time and frequency domains. No differences were observed for body composition, blood pressure, glycemia nor lipids between groups. CT group presented resting bradycardia. Heart rate variability was increased in cyclists, as well as the parameters of parasympathetic modulation. Sympathetic modulation was reduced in CT group when compared to IA group. Additionally, positive correlations were observed between resting heart rate and RMSSD and heart rate variability, while heart rate variability was correlated with sympathovagal balance. Our results demonstrated that bicycling regularly used as a means of transport is able to improve cardiovascular autonomic modulation, thus reducing the risk of cardiovascular disease.

  11. Arterial blood pressure and heart rate regulation in shock state.

    PubMed

    DellaVolpe, Jeffrey D; Moore, Jason E; Pinsky, Michael R

    2015-10-01

    Circulatory shock is a complicated problem that carries a high risk of complications and mortality for critically ill patients. The heart rate and blood pressure targets to which a patient in shock should be resuscitated remain a challenge to intensivists. While the ideal blood pressure and heart rate in circulatory shock are still not definitive, recent studies have begun to refine these targets. A recent trial comparing a mean arterial pressure target of 80-85 mmHg with a target of 65-70 mmHg showed no difference in mortality, with a decreased need for renal replacement therapy in patients with pre-existing hypertension based on subgroup analysis. Regulation of heart rate was defined by a trial demonstrating that heart rate control in patients with severe sepsis on high-dose norepinephrine with esmolol titration did not result in additional adverse events. The ideal target blood pressure in the resuscitation of circulatory shock is variable and likely depends on prior blood pressure. Heart rate regulation with β-blockade appears to be safe in selected patients when accompanied by adequate resuscitation and monitoring.

  12. A comparison of heart rate responses in racquet games.

    PubMed Central

    Docherty, D.

    1982-01-01

    The present study investigated the heart rate response to playing tennis with special reference to the skill levels and ages of the participants. Data obtained in a similar manner during earlier studies of badminton and squash players were compared with that obtained during tennis. The number of rallies, mean rally time and actual playing time in 30 minutes of play was also compared for the different skill levels and sports. Results showed that playing tennis raised the players' heart rates to 68-70% of their predicted maximum heart rate (PMHR). Playing squash and badminton could raise heart rates to 80-85% of the players' PMHR which was significantly higher than the values obtained for tennis. The actual skill level of the participants within their chosen sport did not have a significant effect in predicting the physical demands of squash or tennis but was important in predicting the heart rate response of badminton players. The more skillful the badminton player the greater the cardiac response as a result of game play. Analysis of time spent in actual play revealed that tennis players were involved in play for only five of the thirty minutes of game play, compared to 15 and 10 min respectively for squash and badminton. Skill level within each sport was only a significant factor in predicting length of play for squash players in which the medium and highly skilled groups played significantly longer than those of a lower level of skill. Images p96-a PMID:7104564

  13. Autonomic control of heart rate after exercise in trained wrestlers.

    PubMed

    Henríquez, Olguín C; Báez, San Martín E; Von Oetinger, A; Cañas, Jamett R; Ramírez, Campillo R

    2013-06-01

    The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability - SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05) and in the non linear analysis of HRV from SD130-45s (p <0.05) and SD145-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW.

  14. Heart rate measurement based on face video sequence

    NASA Astrophysics Data System (ADS)

    Xu, Fang; Zhou, Qin-Wu; Wu, Peng; Chen, Xing; Yang, Xiaofeng; Yan, Hong-jian

    2015-03-01

    This paper proposes a new non-contact heart rate measurement method based on photoplethysmography (PPG) theory. With this method we can measure heart rate remotely with a camera and ambient light. We collected video sequences of subjects, and detected remote PPG signals through video sequences. Remote PPG signals were analyzed with two methods, Blind Source Separation Technology (BSST) and Cross Spectral Power Technology (CSPT). BSST is a commonly used method, and CSPT is used for the first time in the study of remote PPG signals in this paper. Both of the methods can acquire heart rate, but compared with BSST, CSPT has clearer physical meaning, and the computational complexity of CSPT is lower than that of BSST. Our work shows that heart rates detected by CSPT method have good consistency with the heart rates measured by a finger clip oximeter. With good accuracy and low computational complexity, the CSPT method has a good prospect for the application in the field of home medical devices and mobile health devices.

  15. Concurrent validity of the Armour39 heart rate monitor strap.

    PubMed

    Flanagan, Shawn D; Comstock, Brett A; Dupont, William H; Sterczala, Adam R; Looney, Dave P; Dombrowski, Dylan H; McDermott, Danielle M; Bryce, Alexander; Maladouangdock, Jesse; Dunn-Lewis, Courtenay; Luk, Hui-Ying; Szivak, Tunde K; Hooper, David R; Kraemer, William J

    2014-03-01

    New technology offers potential advantages in physically demanding environments where convenience and comfort are important and accurate and reliable data collection is challenging. Nevertheless, it is important to validate the accuracy and reliability of such biological monitoring systems (BMS) before they are adopted. The purpose of this investigation was to assess the concurrent validity of a new heart rate monitor across a range of exercise intensities and with a large and diverse group of male subjects in a large cohort with diverse physical fitness characteristics. Seventy-five men (age, 23 ± 4 years; height, 181 ± 8 cm; body mass, 83 ± 12 kg; estimated V[Combining Dot Above]O2peak, 3.16 ± 0.63 [L·min]) volunteered and completed a graded cycle ergometer exercise protocol while heart rate was continuously monitored before, during, and after exercise with the new device (Armour39) and the gold standard (electrocardiogram). The 2-minute stages included sitting, standing, and cycling with 35 W increments until volitional fatigue. The coefficient of determination between mean heart rate values at each stage was R = 0.99, whereas Pearson correlations (r) at each stage were ≥ 0.99. Heart rates during exercise were typically within 1 beat of each other. The Armour39 BMS, therefore, is an acceptable means for the valid and reliable determination of heart rate under various bodily positions and levels of exertion, including maximal exercise intensity.

  16. AUTONOMIC CONTROL OF HEART RATE AFTER EXERCISE IN TRAINED WRESTLERS

    PubMed Central

    Báez, San Martín E.; Von Oetinger, A.; Cañas, Jamett R.; Ramírez, Campillo R.

    2013-01-01

    The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability – SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05) and in the non linear analysis of HRV from SD130-45s (p <0.05) and SD145-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW. PMID:24744476

  17. Preparatory heart rate patterns in competitive rifle shooting.

    PubMed

    Konttinen, N; Lyytinen, H; Viitasalo, J

    1998-04-01

    In this study, we examined the relationship between preparatory heart rate patterns and competitive shooting performance. Cardiac activity was recorded from six elite and six non-elite male rifle shooters during the 6 s before the trigger pull. The assessment of shooting performance was based on three variables: shooting score, rifle stability and electromyographic (EMG) activity in the upper body. Each shooter showed a decrease in the pre-trigger heart rate that did not covary with the shooting scores. The magnitude of this change was greater for the non-elite shooters compared to the elite shooters, suggesting that the heart rate patterns reflected skill-related aspects of preparatory performance. The analyses of rifle-hold performance (rifle stability and EMG) suggested that the observed heart rate changes were associated with a shooter's attempts to achieve a rigid rifle position, but depend on his skill level. Interpretation of preparatory heart rate patterns in competitive rifle shooting should not be based solely on the attentional focusing aspect, but should also take into account the effects of a shooter's psychomotor regulation.

  18. The Use of Heart Rate Monitors in Physical Education

    ERIC Educational Resources Information Center

    Nichols, Randall; Davis, Kathryn L.; McCord, Tim; Schmidt, Dave; Slezak, Alex M.

    2009-01-01

    The ever-rising rate of obesity and the need for increased physical activity for young children is well documented. Data suggests that today's youth are not participating in enough quality health-enhancing physical activity either in or outside of school. Heart rate monitors have been used by adult exercisers for many years to monitor and assess…

  19. The Use of Heart Rate Monitors in Physical Education

    ERIC Educational Resources Information Center

    Nichols, Randall; Davis, Kathryn L.; McCord, Tim; Schmidt, Dave; Slezak, Alex M.

    2009-01-01

    The ever-rising rate of obesity and the need for increased physical activity for young children is well documented. Data suggests that today's youth are not participating in enough quality health-enhancing physical activity either in or outside of school. Heart rate monitors have been used by adult exercisers for many years to monitor and assess…

  20. Optimization of pharmacotherapy in chronic heart failure: is heart rate adequately addressed?

    PubMed

    Franke, Jennifer; Wolter, Jan Sebastian; Meme, Lillian; Keppler, Jeannette; Tschierschke, Ramon; Katus, Hugo A; Zugck, Christian

    2013-01-01

    The aim of the study is to evaluate the use of beta-blockers in chronic heart failure (CHF) and the extent of heart rate reduction achieved in clinical practice and to determine differences in outcome of patients who fulfilled select inclusion criteria of the SHIFT study according to resting heart rate modulated by beta-blocker therapy. We evaluated an all-comer population of our dedicated CHF outpatient clinic between 2006 and 2010. For inclusion, individually optimized doses of guideline-recommended pharmacotherapy including beta-blockers had to be maintained for at least 3 months and routine follow-up performed at our outpatient CHF-clinic thereafter. Treatment dosages of beta-blockers, and demographic and clinical profiles including resting heart rate were assessed. The outcome of patients who fulfilled select inclusion criteria of the SHIFT study (left-ventricular ejection fraction (LVEF) ≤35 %, sinus rhythm, NYHA II-IV) and were followed-up for at least 1 year was stratified according to resting heart rates: ≥75 versus <75 bpm and ≥70 versus <70 bpm. The composite primary endpoint was defined as all-cause death or hospital admission for worsening heart failure during 12-month follow-up. In total, 3,181 patients were assessed in regard to treatment dosages of beta-blockers, and demographic and clinical profiles including resting heart rate. Of the overall studied population, 443 patients fulfilled all inclusion criteria and entered outcome analysis. Median observation time of survivors was 27.5 months with 1,039.7 observation-years in total. Up-titration to at least half the evidence-based target dose of beta-blockers was achieved in 69 % and full up-titration in 29 % of these patients. Patients with increased heart rates were younger, more often male, exhibited a higher NYHA functional class and lower LVEF. The primary endpoint occurred in 21 % of patients in the ≥70 bpm group versus 9 % of patients in the group with heart rates <70

  1. Heart rate and heart rate variability in pregnant dairy cows and their fetuses determined by fetomaternal electrocardiography.

    PubMed

    Trenk, Lisa; Kuhl, Juliane; Aurich, Jörg; Aurich, Christine; Nagel, Christina

    2015-11-01

    In this study, fetomaternal electrocardiograms were recorded once weekly in cattle during the last 14 weeks of gestation. From the recorded beat-to-beat (RR) intervals, heart rate and heart rate variability (HRV) variables standard deviation of the RR interval (SDRR) and root mean square of successive RR differences (RMSSD) were calculated. To differentiate between effects of lactation and gestation, pregnant lactating (PL) cows (n = 7) and pregnant nonlactating (PNL) heifers (n = 8) were included. We hypothesized that lactation is associated with stress detectable by HRV analysis. We also followed the hypothesis that heart rate and HRV are influenced by growth and maturation of the fetus toward term. Maternal heart rate changed over time in both groups, and in PL cows, it decreased with drying-off. During the last 5 weeks of gestation, maternal heart rate increased in both groups but was lower in PL cows than in PNL heifers. Maternal HRV did not change over time, but SDRR was significantly higher in PL cows than in PNL heifers, and significant interactions of group × time existed. On the basis of HRV, undisturbed pregnancies are thus no stressor for the dam in cattle. Fetal heart rate decreased from week 14 to week 1 before birth with no difference between groups. Gestational age thus determines heart rate in the bovine fetus. The HRV variables SDRR and RMSSD increased toward the end of gestation in fetuses carried by cows but not in those carried by heifers. The increase in HRV indicates maturation of fetal cardiac regulation which may be overrun by high sympathoadrenal activity in fetuses carried by heifers as suggested by their low HRV. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Fish oil reduces heart rate and oxygen consumption during exercise.

    PubMed

    Peoples, Gregory E; McLennan, Peter L; Howe, Peter R C; Groeller, Herbert

    2008-12-01

    Dietary omega-3 polyunsaturated fatty acids (PUFAs) are readily incorporated into heart and skeletal muscle membranes where, in the heart, animal studies show they reduce O2 consumption. To test the hypothesis that omega-3 PUFAs alter O2 efficiency in humans, the effects of fish oil (FO) supplementation on O2 consumption during exercise were evaluated. Sixteen well-trained men (cyclists), randomly assigned to receive 8 x 1 g capsules per day of olive oil (control) or FO for 8 weeks in a double-blind, parallel design, completed the study (control: n = 7, age 27.1 +/- 2.7 years; FO: n = 9, age 23.2 +/- 1.2 years). Subjects used an electronically braked cycle ergometer to complete peak O2 consumption tests (VO 2peak) and sustained submaximal exercise tests at 55% of peak workload (from the VO 2peak test) before and after supplementation. Whole-body O2 consumption and indirect measurements of myocardial O2 consumption [heart rate and rate pressure product (RPP)] were assessed. FO supplementation increased omega-3 PUFA content of erythrocyte cell membranes. There were no differences in VO 2peak (mL kg(-1) min(-1)) (control: pre 66.8 +/- 2.4, post 67.2 +/- 2.3; FO: pre 68.3 +/- 1.4, post 67.2 +/- 1.2) or peak workload after supplementation. The FO supplementation lowered heart rate (including peak heart rate) during incremental workloads to exhaustion (P < 0.05). In addition, the FO supplementation lowered steady-state submaximal exercise heart rate, whole-body O2 consumption, and RPP (P < 0.01). Time to voluntary fatigue was not altered by FO supplementation. This study indicates that FOs may act within the healthy heart and skeletal muscle to reduce both whole-body and myocardial O2 demand during exercise, without a decrement in performance.

  3. Neuroanatomical substrates for the volitional regulation of heart rate

    PubMed Central

    Jones, Catherine L.; Minati, Ludovico; Nagai, Yoko; Medford, Nick; Harrison, Neil A.; Gray, Marcus; Ward, Jamie; Critchley, Hugo D.

    2015-01-01

    The control of physiological arousal can assist in the regulation of emotional state. A subset cortical and subcortical brain regions are implicated in autonomic control of bodily arousal during emotional behaviors. Here, we combined human functional neuroimaging with autonomic monitoring to identify neural mechanisms that support the volitional regulation of heart rate, a process that may be assisted by visual feedback. During functional magnetic resonance imaging (fMRI), 15 healthy adults performed an experimental task in which they were prompted voluntarily to increase or decrease cardiovascular arousal (heart rate) during true, false, or absent visual feedback. Participants achieved appropriate changes in heart rate, without significant modulation of respiratory rate, and were overall not influenced by the presence of visual feedback. Increased activity in right amygdala, striatum and brainstem occurred when participants attempted to increase heart rate. In contrast, activation of ventrolateral prefrontal and parietal cortices occurred when attempting to decrease heart rate. Biofeedback enhanced activity within occipito-temporal cortices, but there was no significant interaction with task conditions. Activity in regions including pregenual anterior cingulate and ventral striatum reflected the magnitude of successful task performance, which was negatively related to subclinical anxiety symptoms. Measured changes in respiration correlated with posterior insula activation and heart rate, at a more lenient threshold, change correlated with insula, caudate, and midbrain activity. Our findings highlight a set of brain regions, notably ventrolateral prefrontal cortex, supporting volitional control of cardiovascular arousal. These data are relevant to understanding neural substrates supporting interaction between intentional and interoceptive states related to anxiety, with implications for biofeedback interventions, e.g., real-time fMRI, that target emotional

  4. Heart rate variability predicts the magnitude of heart rate decrease after fingolimod initiation.

    PubMed

    Simula, Sakari; Laitinen, Tomi P; Laitinen, Tiina M; Hartikainen, Päivi; Hartikainen, Juha Ek

    2016-11-01

    Fingolimod is an immunomodulator with a disease modifying effect on relapsing-remitting multiple sclerosis (RRMS). A heart rate (HR) decrease shortly after fingolimod initiation, however, requires a clinical vigilance. The aim of this study was to prospectively investigate whether cardiac autonomic regulation can predict the magnitude of HR decrease after fingolimod initiation. Twenty-five patients with RRMS underwent ambulatory 24-h electrocardiogram recording to assess HR variability 20±16 days before fingolimod initiation (baseline) and repeated at the day of fingolimod initiation to assess the magnitude of HR decrease. The percentage of normal RR-intervals with duration more than 50ms different from the previous normal RR-interval (pNN50) was calculated (among the other HR variability parameters) to assess cardiac autonomic regulation. The maximal HR decrease (ΔHR) after the first dose of fingolimod was assessed in absolute units (beats/min) and in percentage (%). The maximal ΔHR was -20±11 beats/min (-23±12%) on the average. pNN50 calculated at baseline correlated with ΔHR% (r=-0.657, p<0.001). A HR decrease ≥20% was found in 10/14 patients with pNN50≥10%. The positive and negative predictive values of pNN50≥10% to predict ΔHR≥20% were 83% and 69%, respectively leading to accuracy of 76%. Cardiac autonomic regulation (pNN50>10%) at baseline can be used to predict the magnitude of HR decrease after the first dose of fingolimod. ClinicalTrials.gov (NCT01704183). Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Heart rate variability and nonlinear analysis of heart rate dynamics following single and multiple Wingate bouts.

    PubMed

    Millar, Philip J; Rakobowchuk, Mark; McCartney, Neil; MacDonald, Maureen J

    2009-10-01

    Sprint interval training involves short bouts of high-intensity exercise and has produced training responses similar to those of endurance training. The effects of multiple supramaximal exercise bouts on neurocardiac modulation have not been examined. Therefore, we investigated the recovery of heart rate (HR) variability and nonlinear HR dynamics in 10 young (20.1 +/- 1.2 years) healthy males following single (1) and multiple (4) Wingate tests. HR variability was assessed with time and frequency domain measures, whereas nonlinear HR dynamics were determined by assessing the complexity (sample entropy) and fractal nature (detrended fluctuation analysis) of the HR time series. Responses were determined at pre-exercise baseline and at 3 time points during recovery from exercise: Post1 (5-20 min), Post2 (45-60 min), and Post3 (105-120 min). Following a single Wingate test, all temporal and spectral HR measures had returned to baseline by 1 h of recovery. In contrast, these measures were different from baseline at 2 h following multiple Wingate tests. Fractal HR properties were altered (p < 0.05) at Post1 following a single Wingate test and at Post1 and Post2 following multiple Wingate tests. HR complexity was reduced (p < 0.001) throughout the 2-h recovery following both exercise conditions. In conclusion, Wingate tests result in alterations in cardiac autonomic control, with multiple Wingate tests resulting in larger, more prolonged alterations. Based on the results of the single Wingate test, nonlinear measures, such as HR complexity, may be more sensitive in detecting subtle alterations in neurocardiac behaviour, compared with traditional measures of HR variability.

  6. Asymmetric acceleration/deceleration dynamics in heart rate variability

    NASA Astrophysics Data System (ADS)

    Alvarez-Ramirez, J.; Echeverria, J. C.; Meraz, M.; Rodriguez, E.

    2017-08-01

    The heart rate variability (HRV) is an important physiological signal used either to assess the risk of cardiac death or to model the cardiovascular regulatory dynamics. Asymmetries in HRV data have been observed using 2D Poincare plots, which have been linked to a non-equilibrium operation of the cardiac autonomic system. This work further explores the presence of asymmetries but in the serial correlations of the dynamics of HRV data. To this end, detrended fluctuation analysis (DFA) was used to estimate the Hurst exponent both when the heart rate is accelerating and when it is decelerating. The analysis is conducted using data collected from subjects under normal sinus rhythm (NSR), congestive heart failure (CHF) and atrial fibrillation (AF) . For the NSR cases, it was found that correlations are stronger (p < 0 . 05) when the heart rate is accelerating than when it is decelerating over different scales in the range 20-40 beats. In contrast, the opposite behavior was detected for the CHF and AF patients. Possible links between asymmetric correlations in the dynamics and the mechanisms controlling the operation of the heart rate are discussed, as well as their implications for modeling the cardiovascular regulatory dynamics.

  7. Is the normal heart rate ``chaotic'' due to respiration?

    NASA Astrophysics Data System (ADS)

    Wessel, Niels; Riedl, Maik; Kurths, Jürgen

    2009-06-01

    The incidence of cardiovascular diseases increases with the growth of the human population and an aging society, leading to very high expenses in the public health system. Therefore, it is challenging to develop sophisticated methods in order to improve medical diagnostics. The question whether the normal heart rate is chaotic or not is an attempt to elucidate the underlying mechanisms of cardiovascular dynamics and therefore a highly controversial topical challenge. In this contribution we demonstrate that linear and nonlinear parameters allow us to separate completely the data sets of the three groups provided for this controversial topic in nonlinear dynamics. The question whether these time series are chaotic or not cannot be answered satisfactorily without investigating the underlying mechanisms leading to them. We give an example of the dominant influence of respiration on heart beat dynamics, which shows that observed fluctuations can be mostly explained by respiratory modulations of heart rate and blood pressure (coefficient of determination: 96%). Therefore, we recommend reformulating the following initial question: "Is the normal heart rate chaotic?" We rather ask the following: "Is the normal heart rate `chaotic' due to respiration?"

  8. Is the normal heart rate "chaotic" due to respiration?

    PubMed

    Wessel, Niels; Riedl, Maik; Kurths, Jürgen

    2009-06-01

    The incidence of cardiovascular diseases increases with the growth of the human population and an aging society, leading to very high expenses in the public health system. Therefore, it is challenging to develop sophisticated methods in order to improve medical diagnostics. The question whether the normal heart rate is chaotic or not is an attempt to elucidate the underlying mechanisms of cardiovascular dynamics and therefore a highly controversial topical challenge. In this contribution we demonstrate that linear and nonlinear parameters allow us to separate completely the data sets of the three groups provided for this controversial topic in nonlinear dynamics. The question whether these time series are chaotic or not cannot be answered satisfactorily without investigating the underlying mechanisms leading to them. We give an example of the dominant influence of respiration on heart beat dynamics, which shows that observed fluctuations can be mostly explained by respiratory modulations of heart rate and blood pressure (coefficient of determination: 96%). Therefore, we recommend reformulating the following initial question: "Is the normal heart rate chaotic?" We rather ask the following: "Is the normal heart rate 'chaotic' due to respiration?"

  9. Increased Heart Rate Variability but Normal Resting Metabolic Rate in Hypocretin/Orexin-Deficient Human Narcolepsy

    PubMed Central

    Fronczek, Rolf; Overeem, Sebastiaan; Reijntjes, Robert; Lammers, Gert Jan; van Dijk, J. Gert; Pijl, Hanno

    2008-01-01

    Study Objectives: We investigated autonomic balance and resting metabolic rate to explore their possible involvement in obesity in hypocretin/orexin-deficient narcoleptic subjects. Methods: Resting metabolic rate (using indirect calorimetry) and variability in heart rate and blood pressure were determined in the fasted resting state. Subjects included 15 untreated, hypocretin-deficient male narcoleptics and 15 male controls matched for age and body mass index. Results: Spectral power analysis revealed greater heart rate and blood pressure variability in hypocretin-deficient male narcoleptic patients (heart rate: p = 0.01; systolic blood pressure: p = 0.02; diastolic: p < 0.01). The low to high frequency ratio of heart rate power did not differ between groups (p = 0.48), nor did resting metabolic rate (controls: 1767 ± 226 kcal/24 h; patients: 1766 ± 227 kcal/24h; p = 0.99). Conclusions: Resting metabolic rate was not reduced in hypocretin-deficient narcoleptic men and therefore does not explain obesity in this group. Whether the increased heart rate and blood pressure variability—suggesting reduced sympathetic tone—is involved in this regard remains to be elucidated. Citation: Fronczek R; Overeem S; Reijntjes R; Lammers GJ; van Dijk JG; Pijl H. Increased heart rate variability but normal resting metabolic rate in hypocretin/orexin-deficient human narcolepsy. J Clin Sleep Med 2008;4(3):248–254. PMID:18595438

  10. Universal structures of normal and pathological heart rate variability.

    PubMed

    Gañán-Calvo, Alfonso M; Fajardo-López, Juan

    2016-02-25

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient.

  11. Universal structures of normal and pathological heart rate variability

    PubMed Central

    Gañán-Calvo, Alfonso M.; Fajardo-López, Juan

    2016-01-01

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient. PMID:26912108

  12. Exaggerated heart rate oscillations during two meditation techniques.

    PubMed

    Peng, C K; Mietus, J E; Liu, Y; Khalsa, G; Douglas, P S; Benson, H; Goldberger, A L

    1999-07-31

    We report extremely prominent heart rate oscillations associated with slow breathing during specific traditional forms of Chinese Chi and Kundalini Yoga meditation techniques in healthy young adults. We applied both spectral analysis and a novel analytic technique based on the Hilbert transform to quantify these heart rate dynamics. The amplitude of these oscillations during meditation was significantly greater than in the pre-meditation control state and also in three non-meditation control groups: i) elite athletes during sleep, ii) healthy young adults during metronomic breathing, and iii) healthy young adults during spontaneous nocturnal breathing. This finding, along with the marked variability of the beat-to-beat heart rate dynamics during such profound meditative states, challenges the notion of meditation as only an autonomically quiescent state.

  13. [An Algorithm for Correcting Fetal Heart Rate Baseline].

    PubMed

    Li, Xiaodong; Lu, Yaosheng

    2015-10-01

    Fetal heart rate (FHR) baseline estimation is of significance for the computerized analysis of fetal heart rate and the assessment of fetal state. In our work, a fetal heart rate baseline correction algorithm was presented to make the existing baseline more accurate and fit to the tracings. Firstly, the deviation of the existing FHR baseline was found and corrected. And then a new baseline was obtained finally after treatment with some smoothing methods. To assess the performance of FHR baseline correction algorithm, a new FHR baseline estimation algorithm that combined baseline estimation algorithm and the baseline correction algorithm was compared with two existing FHR baseline estimation algorithms. The results showed that the new FHR baseline estimation algorithm did well in both accuracy and efficiency. And the results also proved the effectiveness of the FHR baseline correction algorithm.

  14. Dopamine and noradrenaline are unrelated to renalase, heart rate, and blood pressure in heart transplant recipients.

    PubMed

    Wasilewski, G; Przybyłowski, P; Janik, L; Nowak, E; Sadowski, J; Małyszko, J

    2014-10-01

    Renalase may degrade catecholamines and regulate sympathetic tone and blood pressure. The aim of this study was to assess dopamine, norepinephrine, and renalase in 80 heart transplant recipients and 22 healthy volunteers and their correlations with heart rate, blood pressure control, type of hypotensive therapy, and renal function. Renalase, dopamine, and norepinephrine were studied by using commercially available assays. Renalase levels were higher in heart transplant recipients compared with healthy volunteers, and noradrenaline levels were lower in the studied cohort patients than in the healthy volunteers. Noradrenaline was correlated with white blood cell count (r = -0.21, P < .05), copeptin (r = 0.41, P < .01), and left ventricular diameter (r = -0.29, P < .05), whereas dopamine was correlated in univariate analysis with white blood cell count (r = -0.22, P < .05), posterior wall of left ventricular diameter (r = 0.58, P < .01), and left atrium diameter (r = -0.31, P < .05). Neither noradrenaline nor dopamine was correlated with heart rate, blood pressure, kidney function, or New York Heart Association class. Noradrenaline was significantly higher in patients with elevated diastolic blood pressure (>90 mm Hg) compared with those with normal diastolic blood pressure (P < .05). Renalase was related to kidney function but was unrelated to catecholamines. Elevated renalase levels in heart transplant patients were related to kidney function but not linked to the sympathetic nervous system activity in this study population. In heart transplant recipients, these findings might suggest that sympathetic denervation and the modulation of β-receptors persist.

  15. Influence of energy drinks and alcohol on post-exercise heart rate recovery and heart rate variability.

    PubMed

    Wiklund, Urban; Karlsson, Marcus; Oström, Mats; Messner, Torbjörn

    2009-01-01

    Media have anecdotally reported that drinking energy drinks in combination with alcohol and exercise could cause sudden cardiac death. This study investigated changes in the electrocardiogram (ECG) and heart rate variability after intake of an energy drink, taken in combination with alcohol and exercise. Ten healthy volunteers (five men and five women aged 19-30) performed maximal bicycle ergometer exercise for 30 min after: (i) intake of 0.75 l of an energy drink mixed with alcohol; (ii) intake of energy drink; and, (iii) no intake of any drink. ECG was continuously recorded for analysis of heart rate variability and heart rate recovery. No subject developed any clinically significant arrhythmias. Post-exercise recovery in heart rate and heart rate variability was slower after the subjects consumed energy drink and alcohol before exercise, than after exercise alone. The healthy subjects developed blunted cardiac autonomic modulation after exercising when they had consumed energy drinks mixed with alcohol. Although they did not develop any significant arrhythmia, individuals predisposed to arrhythmia by congenital or other rhythm disorders could have an increased risk for malignant cardiac arrhythmia in similar situations.

  16. Repeated heart rate measurement and cardiovascular outcomes in left ventricular systolic dysfunction.

    PubMed

    Hamill, Victoria; Ford, Ian; Fox, Kim; Böhm, Michael; Borer, Jeffrey S; Ferrari, Roberto; Komajda, Michel; Steg, Philippe Gabriel; Tavazzi, Luigi; Tendera, Michal; Swedberg, Karl

    2015-10-01

    Elevated resting heart rate is associated with increased cardiovascular risk, particularly in patients with left ventricular systolic dysfunction. Heart rate is not monitored routinely in these patients. We hypothesized that routine monitoring of heart rate would increase its prognostic value in patients with left ventricular systolic dysfunction. We analyzed the relationship between heart rate measurements and a range of adverse cardiovascular outcomes, including hospitalization for worsening heart failure, in the pooled placebo-treated patients from the morBidity-mortality EvAlUaTion of the If inhibitor ivabradine in patients with coronary disease and left ventricULar dysfunction (BEAUTIFUL) trial and Systolic Heart failure treatment with the If inhibitor ivabradine (SHIFT) Trial, using standard and time-varying covariate Cox proportional hazards models. By adjusting for other prognostic factors, models were fitted for baseline heart rate alone or for time-updated heart rate (latest heart rate) alone or corrected for baseline heart rate or for immediate previous time-updated heart rate. Baseline heart rate was strongly associated with all outcomes apart from hospitalization for myocardial infarction. Time-updated heart rate increased the strengths of associations for all outcomes. Adjustment for baseline heart rate or immediate previous time-updated heart rate modestly reduced the prognostic importance of time-updated heart rate. For hospitalization for worsening heart failure, each 5 beats/min increase in baseline heart rate and time-updated heart rate was associated with a 15% (95% confidence interval, 12-18) and 22% (confidence interval, 19-40) increase in risk, respectively. Even after correction, the prognostic value of time-updated heart rate remained greater. In patients with left ventricular systolic dysfunction, time-updated heart rate is more strongly related with adverse cardiovascular outcomes than baseline heart rate. Heart rate should be measured to

  17. Co-ordinating Notch, BMP, and TGFβ Signalling During Heart Valve Development

    PubMed Central

    Garside, Victoria C.; Chang, Alex C.; Karsan, Aly; Hoodless, Pamela A.

    2015-01-01

    Congenital heart defects affect approximately 1–5% of human newborns each year and of these cardiac defects, 20–30% are due to heart valve abnormalities. Recent literature indicates that key factors and pathways that regulate valve development are also implicated in congenital heart defects and valve disease. Currently, there are limited options for treatment of valve disease and therefore, having a better understanding of valve development can contribute critical insight into congenital valve defects and disease. There are three major signalling pathways required for early specification and initiation of Endothelial-to-Mesenchymal Transformation (EMT) in the cardiac cushions: BMP, TGFβ, and Notch signalling. BMPs secreted from the myocardium setup the environment for the overlying endocardium to become activated, Notch signalling initiates EMT, and both BMP and TGFβ signalling synergizes with Notch to promote the transition of endothelia to mesenchyme and to promote mesenchymal cell invasiveness. Together, these three essential signalling pathways help to form the cardiac cushions and populate them with mesenchyme and, consequently, set off the cascade of events required to develop mature heart valves. Furthermore, integration and cross-talk between these pathways generate highly stratified and delicate valve leaflets and septa of the heart. Here, we discuss BMP, TGFβ, and Notch signalling pathways during mouse cardiac cushion formation and how they together produce a coordinated EMT response in the developing mouse valves. PMID:23161060

  18. Model for complex heart rate dynamics in health and diseases

    NASA Astrophysics Data System (ADS)

    Kotani, Kiyoshi; Struzik, Zbigniew R.; Takamasu, Kiyoshi; Stanley, H. Eugene; Yamamoto, Yoshiharu

    2005-10-01

    A physiologically motivated, dynamical model of cardiovascular autonomic regulation is shown to be capable of generating long-range correlated and multifractal heart rate. Virtual disease simulations are carried out systematically to account for the disease-induced relative dysfunction of the parasympathetic and the sympathetic branches of the autonomic control. Statistical agreement of the simulation results with those of real life data is reached, suggesting the possible use of the model as a state-of-the-art basis for further understanding of the physiological correlates of complex heart rate dynamics.

  19. Heart Rate Monitor for Portable MP3 Player.

    PubMed

    Kim, Jaywoo; Lee, Mi-Hee; Lee, Hyoung-Ki; Choi, Kiwan; Bang, Seokwon; Kim, Sangryong

    2005-01-01

    This paper presents a photoplethysmography sensor based on a heart rate monitor for a portable MP3 player. Two major design issues are addressed: one is to acquire the sensor signal with a proper amplitude despite a wide range of variation and the other is to handle the noise contaminated signal which is caused by a motion artifact. A benchmarking test with a professional medical photoplethysmography sensor shows that our device performs very well in calculating heart rate even though our photoplethysmography sensor module was designed to be cost effective.

  20. The effect of relaxing music on heart rate and heart rate variability during ECG GATED-myocardial perfusion scintigraphy.

    PubMed

    Tan, Yusuf Ziya; Ozdemir, Semra; Temiz, Ahmet; Celik, Fatmanur

    2015-05-01

    The positive changes in human behavior caused by relaxing music demonstrate the psychological effect of music on human body. A meta-analytical study has shown that relaxing music affects blood pressure and heart rate in coronary heart patients and cancer patients. The aim of our study is to research whether there is a significant effect on heart rate and heart rate variability due to listening to relaxing music during ECG GATED MPS imaging under gamma camera. The music group (n = 50 patients) could choose from 15 different musical types including folk music (no lyric). The other 50 patients were placed in a "no music group" and did not get headphones or any music. There was a statistically significant reduction in the heart rate of patients in the music group compared to those in the control group. Relaxing music provides great benefits to both patient and clinician. There is close relationship between relaxing music and health procedure, can use every area of the health noninvasiv, safe, cheap and is a method don't have side effect. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Impairment of heart rate recovery after peak exercise predicts poor outcome after pediatric heart transplantation.

    PubMed

    Giardini, Alessandro; Fenton, Matthew; Derrick, Graham; Burch, Michael

    2013-09-10

    A blunted heart rate recovery (HRR) from peak exercise is associated with adverse outcome in adults with ischemic heart disease. We assessed HRR after pediatric heart transplantation (HTx) and its prognostic use. Between 2004 and 2010 we performed 360 maximal exercise tests (median, 2 tests/patient; range, 1-7) in 128 children (66 men; age at test, 14 ± 3 years) who received HTx (age, 8.5 ± 5.1 years) because of cardiomyopathy (66%) or congenital heart defects (34%). The change in heart rate from peak exercise to 1 minute of recovery was measured as HRR and was expressed as Z score calculated from reference data obtained in 160 healthy children. HRR was impaired soon after HTx (average in first 2 years Z=-1.9 ± 3.5) but improved afterward (Z=+0.52/y), such that HRR Z score normalized in most patients by 6 years after HTx (average, 0.6 ± 1.8). A subsequent decline in HRR Z score was noted from 6 years after HTx (rate of Z=-0.11/y). After 27 ± 15 months from the most recent exercise test, 19 patients died or were re-heart transplantation. For the follow-up after 6 years, HRR Z score was the only predictor of death/re-heart transplantation (P=0.003). Patients in the lowest quartile of HRR Z score had a much higher 5-year event rate (event-free rate, 29% versus 84%; hazard ratio, 7.0; P=0.0013). HRR is blunted soon after HTx but normalizes at ≈ 6 years, potentially as a result of parasympathetic reinnervation of the graft, but then declines. This late decline in HRR Z score is associated with worse outcome.

  2. Direct observation of homoclinic orbits in human heart rate variability

    NASA Astrophysics Data System (ADS)

    Żebrowski, J. J.; Baranowski, R.

    2003-05-01

    Homoclinic trajectories of the interbeat intervals between contractions of ventricles of the human heart are identified. The interbeat intervals are extracted from 24-h Holter ECG recordings. Three such recordings are discussed in detail. Mappings of the measured consecutive interbeat intervals are constructed. In the second and in some cases in the fourth iterate of the map of interbeat intervals homoclinic trajectories associated with a hyperbolic saddle are found. The homoclinic trajectories are often persistent for many interbeat intervals, sometimes spanning many thousands of heartbeats. Several features typical for homoclinic trajectories found in other systems were identified, including a signature of the gluing bifurcation. The homoclinic trajectories are present both in recordings of heart rate variability obtained from patients with an increased number of arrhythmias and in cases in which the sinus rhythm is dominant. The results presented are a strong indication of the importance of deterministic nonlinear instabilities in human heart rate variability.

  3. Inhalation of ultrafine carbon particles alters heart rate and heart rate variability in people with type 2 diabetes.

    PubMed

    Vora, Rathin; Zareba, Wojciech; Utell, Mark J; Pietropaoli, Anthony P; Chalupa, David; Little, Erika L; Oakes, David; Bausch, Jan; Wiltshire, Jelani; Frampton, Mark W

    2014-07-16

    Diabetes may confer an increased risk for the cardiovascular health effects of particulate air pollution, but few human clinical studies of air pollution have included people with diabetes. Ultrafine particles (UFP, ≤100 nm in diameter) have been hypothesized to be an important component of particulate air pollution with regard to cardiovascular health effects. 17 never-smoker subjects 30-60 years of age, with stable type 2 diabetes but otherwise healthy, inhaled either filtered air (0-10 particles/cm3) or elemental carbon UFP (~107 particles/cm3, ~50 ug/m3, count median diameter 32 nm) by mouthpiece, for 2 hours at rest, in a double-blind, randomized, crossover study design. A digital 12-lead electrocardiogram (ECG) was recorded continuously for 48 hours, beginning 1 hour prior to exposure. Analysis of 5-minute segments of the ECG during quiet rest showed reduced high-frequency heart rate variability with UFP relative to air exposure (p = 0.014), paralleled by non-significant reductions in time-domain heart rate variability parameters. In the analysis of longer durations of the ECG, we found that UFP exposure increased the heart rate relative to air exposure. During the 21- to 45-hour interval after exposure, the average heart rate increased approximately 8 beats per minute with UFP, compared to 5 beats per minute with air (p = 0.045). There were no UFP effects on cardiac rhythm or repolarization. Inhalation of elemental carbon ultrafine particles alters heart rate and heart rate variability in people with type 2 diabetes. Our findings suggest that effects may occur and persist hours after a single 2-hour exposure.

  4. Heart-Rate Recovery After Warm-up in Swimming: A Useful Predictor of Training Heart-Rate Response?

    PubMed

    Ganzevles, Sander P M; de Haan, Arnold; Beek, Peter J; Daanen, Hein A M; Truijens, Martin J

    2017-07-01

    For training to be optimal, daily training load has to be adapted to the momentary status of the individual athlete, which is often difficult to establish. Therefore, the current study investigated the predictive value of heart-rate recovery (HRR) during a standardized warm-up for training load. Training load was quantified by the variation in heart rate during standardized training in competitive swimmers. Eight female and 5 male Dutch national-level swimmers participated in the study. They all performed 3 sessions consisting of a 300-m warm-up test and a 10 × 100-m training protocol. Both protocols were swum in front crawl at individually standardized velocities derived from an incremental step test. Velocity was related to 75% and 85% heart-rate reserve (% HRres) for the warm-up and training, respectively. Relative HRR during the first 60 s after the warm-up (HRRw-up) and differences between the actual and intended heart rate for the warm-up and the training (ΔHRw-up and ΔHRtr) were determined. No significant relationship between HRRw-up and ΔHRtr was found (F1,37 = 2.96, P = .09, R(2) = .07, SEE = 4.65). There was considerable daily variation in ΔHRtr at a given swimming velocity (73-93% HRres). ΔHRw-up and ΔHRtr were clearly related (F1,37 = 74.31, P < .001, R(2) = .67, SEE = 2.78). HRR after a standardized warm-up does not predict heart rate during a directly subsequent and standardized training session. Instead, heart rate during the warm-up protocol seems a promising alternative for coaches to make daily individual-specific adjustments to training programs.

  5. Inhalation of ultrafine carbon particles alters heart rate and heart rate variability in people with type 2 diabetes

    PubMed Central

    2014-01-01

    Background Diabetes may confer an increased risk for the cardiovascular health effects of particulate air pollution, but few human clinical studies of air pollution have included people with diabetes. Ultrafine particles (UFP, ≤100 nm in diameter) have been hypothesized to be an important component of particulate air pollution with regard to cardiovascular health effects. Methods 17 never-smoker subjects 30–60 years of age, with stable type 2 diabetes but otherwise healthy, inhaled either filtered air (0–10 particles/cm3) or elemental carbon UFP (~107 particles/cm3, ~50 ug/m3, count median diameter 32 nm) by mouthpiece, for 2 hours at rest, in a double-blind, randomized, crossover study design. A digital 12-lead electrocardiogram (ECG) was recorded continuously for 48 hours, beginning 1 hour prior to exposure. Results Analysis of 5-minute segments of the ECG during quiet rest showed reduced high-frequency heart rate variability with UFP relative to air exposure (p = 0.014), paralleled by non-significant reductions in time-domain heart rate variability parameters. In the analysis of longer durations of the ECG, we found that UFP exposure increased the heart rate relative to air exposure. During the 21- to 45-hour interval after exposure, the average heart rate increased approximately 8 beats per minute with UFP, compared to 5 beats per minute with air (p = 0.045). There were no UFP effects on cardiac rhythm or repolarization. Conclusions Inhalation of elemental carbon ultrafine particles alters heart rate and heart rate variability in people with type 2 diabetes. Our findings suggest that effects may occur and persist hours after a single 2-hour exposure. PMID:25028096

  6. Circadian Variation of Heart Rate Variability Across Sleep Stages

    PubMed Central

    Boudreau, Philippe; Yeh, Wei-Hsien; Dumont, Guy A.; Boivin, Diane B.

    2013-01-01

    Study Objectives: Nocturnal cardiovascular events are more frequent at the beginning and end of the night. It was proposed that this pattern reflects the nocturnal distribution of sleep and sleep stages. Using heart rate variability (HRV), we recently showed an interaction between the circadian system and vigilance states on the regulation of cardiac rhythmicity. Here, we further investigate this interaction in order to clarify the specific effects of sleep stages on the regulation of the heart. Design: Participants underwent a 72-h ultradian sleep-wake cycle procedure in time isolation consisting of alternating 60-min wake episodes in dim light and 60-min nap opportunities in total darkness. Setting: Time isolation suite. Patients or participants: Fifteen healthy young participants; two were subsequently excluded. Interventions: N/A. Measurements and Results: The current study revealed that sleep onset and progression to deeper sleep stages was associated with a shift toward greater parasympathetic modulation, whereas rapid eye movement (REM) sleep was associated with a shift toward greater sympathetic modulation. We found a circadian rhythm of heart rate (HR) and high-frequency power during wakefulness and all non-REM sleep stages. A significant circadian rhythm of HR and sympathovagal balance of the heart was also observed during REM sleep. During slow wave sleep, maximal parasympathetic modulation was observed at ∼02:00, whereas during REM sleep, maximal sympathetic modulation occurred in the early morning. Conclusion: The circadian and sleep stage-specific effects on heart rate variability are clinically relevant and contribute to the understanding of the degree of cardiovascular vulnerability during sleep. Citation: Boudreau P; Yeh WH; Dumont GA; Boivin DB. Circadian variation of heart rate variability across sleep stages. SLEEP 2013;36(12):1919-1928. PMID:24293767

  7. Evaluation of the metabolic rate based on the recording of the heart rate

    PubMed Central

    MALCHAIRE, Jacques; ALFANO, Francesca Romana d’AMBROSIO; PALELLA, Boris Igor

    2017-01-01

    The assessment of harsh working conditions requires a correct evaluation of the metabolic rate. This paper revises the basis described in the ISO 8996 standard for the evaluation of the metabolic rate at a work station from the recording of the heart rate of a worker during a representative period of time. From a review of the literature, formulas different from those given in the standard are proposed to estimate the maximum working capacity, the maximum heart rate, the heart rate and the metabolic rate at rest and the relation (HR vs. M) at the basis of the estimation of the equivalent metabolic rate, as a function of the age, height and weight of the person. A Monte Carlo simulation is used to determine, from the approximations of these parameters and formulas, the imprecision of the estimated equivalent metabolic rate. The results show that the standard deviation of this estimate varies from 10 to 15%. PMID:28250334

  8. Evaluation of the metabolic rate based on the recording of the heart rate.

    PubMed

    Malchaire, Jacques; d'AMBROSIO Alfano, Francesca Romana; Palella, Boris Igor

    2017-06-08

    The assessment of harsh working conditions requires a correct evaluation of the metabolic rate. This paper revises the basis described in the ISO 8996 standard for the evaluation of the metabolic rate at a work station from the recording of the heart rate of a worker during a representative period of time. From a review of the literature, formulas different from those given in the standard are proposed to estimate the maximum working capacity, the maximum heart rate, the heart rate and the metabolic rate at rest and the relation (HR vs. M) at the basis of the estimation of the equivalent metabolic rate, as a function of the age, height and weight of the person. A Monte Carlo simulation is used to determine, from the approximations of these parameters and formulas, the imprecision of the estimated equivalent metabolic rate. The results show that the standard deviation of this estimate varies from 10 to 15%.

  9. Prediction of Heart Rates on a Ropes Course from Simple Physical Measures. Research Update.

    ERIC Educational Resources Information Center

    Priest, Simon; Montelpare, William

    1995-01-01

    This study identified the highest heart rates attained on a ropes course for a corporate population; examined relationships between highest heart rate and other physical measures (basal heart rate, blood pressure, height, weight, body girths, cholesterol, maximum number of pushups, and heart rate after brisk walk); and developed an equation for…

  10. Prediction of Heart Rates on a Ropes Course from Simple Physical Measures. Research Update.

    ERIC Educational Resources Information Center

    Priest, Simon; Montelpare, William

    1995-01-01

    This study identified the highest heart rates attained on a ropes course for a corporate population; examined relationships between highest heart rate and other physical measures (basal heart rate, blood pressure, height, weight, body girths, cholesterol, maximum number of pushups, and heart rate after brisk walk); and developed an equation for…

  11. Heart Rate Variability in Patients Being Treated for Dengue Viral Infection: New Insights from Mathematical Correction of Heart Rate

    DTIC Science & Technology

    2014-02-25

    the Netherlands) at a sampling rate of 1000Hz and exported at a rate of 200Hz to a computer-based data acquisition software package (WinDAQ, Dataq...Instruments, Akron, OH). The ECG waveforms were imported into data anal- ysis software (WinCPRS, Absolute Aliens, Turku, Finland) using a Labview...WinCPRS software , the following metrics were obtained according to a previously described approach (Ryan et al., 2010) RRI, heart rate (HR), RRI low

  12. Ambulatory heart rate range predicts mode-specific mortality and hospitalisation in chronic heart failure.

    PubMed

    Cubbon, Richard M; Ruff, Naomi; Groves, David; Eleuteri, Antonio; Denby, Christine; Kearney, Lorraine; Ali, Noman; Walker, Andrew M N; Jamil, Haqeel; Gierula, John; Gale, Chris P; Batin, Phillip D; Nolan, James; Shah, Ajay M; Fox, Keith A A; Sapsford, Robert J; Witte, Klaus K; Kearney, Mark T

    2016-02-01

    We aimed to define the prognostic value of the heart rate range during a 24 h period in patients with chronic heart failure (CHF). Prospective observational cohort study of 791 patients with CHF associated with left ventricular systolic dysfunction. Mode-specific mortality and hospitalisation were linked with ambulatory heart rate range (AHRR; calculated as maximum minus minimum heart rate using 24 h Holter monitor data, including paced and non-sinus complexes) in univariate and multivariate analyses. Findings were then corroborated in a validation cohort of 408 patients with CHF with preserved or reduced left ventricular ejection fraction. After a mean 4.1 years of follow-up, increasing AHRR was associated with reduced risk of all-cause, sudden, non-cardiovascular and progressive heart failure death in univariate analyses. After accounting for characteristics that differed between groups above and below median AHRR using multivariate analysis, AHRR remained strongly associated with all-cause mortality (HR 0.991/bpm increase in AHRR (95% CI 0.999 to 0.982); p=0.046). AHRR was not associated with the risk of any non-elective hospitalisation, but was associated with heart-failure-related hospitalisation. AHRR was modestly associated with the SD of normal-to-normal beats (R(2)=0.2; p<0.001) and with peak exercise-test heart rate (R(2)=0.33; p<0.001). Analysis of the validation cohort revealed AHRR to be associated with all-cause and mode-specific death as described in the derivation cohort. AHRR is a novel and readily available prognosticator in patients with CHF, which may reflect autonomic tone and exercise capacity. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  13. Ambulatory heart rate range predicts mode-specific mortality and hospitalisation in chronic heart failure

    PubMed Central

    Cubbon, Richard M; Ruff, Naomi; Groves, David; Eleuteri, Antonio; Denby, Christine; Kearney, Lorraine; Ali, Noman; Walker, Andrew M N; Jamil, Haqeel; Gierula, John; Gale, Chris P; Batin, Phillip D; Nolan, James; Shah, Ajay M; Fox, Keith A A; Sapsford, Robert J; Witte, Klaus K; Kearney, Mark T

    2016-01-01

    Objective We aimed to define the prognostic value of the heart rate range during a 24 h period in patients with chronic heart failure (CHF). Methods Prospective observational cohort study of 791 patients with CHF associated with left ventricular systolic dysfunction. Mode-specific mortality and hospitalisation were linked with ambulatory heart rate range (AHRR; calculated as maximum minus minimum heart rate using 24 h Holter monitor data, including paced and non-sinus complexes) in univariate and multivariate analyses. Findings were then corroborated in a validation cohort of 408 patients with CHF with preserved or reduced left ventricular ejection fraction. Results After a mean 4.1 years of follow-up, increasing AHRR was associated with reduced risk of all-cause, sudden, non-cardiovascular and progressive heart failure death in univariate analyses. After accounting for characteristics that differed between groups above and below median AHRR using multivariate analysis, AHRR remained strongly associated with all-cause mortality (HR 0.991/bpm increase in AHRR (95% CI 0.999 to 0.982); p=0.046). AHRR was not associated with the risk of any non-elective hospitalisation, but was associated with heart-failure-related hospitalisation. AHRR was modestly associated with the SD of normal-to-normal beats (R2=0.2; p<0.001) and with peak exercise-test heart rate (R2=0.33; p<0.001). Analysis of the validation cohort revealed AHRR to be associated with all-cause and mode-specific death as described in the derivation cohort. Conclusions AHRR is a novel and readily available prognosticator in patients with CHF, which may reflect autonomic tone and exercise capacity. PMID:26674986

  14. Heart Rate Variability: Effect of Exercise Intensity on Postexercise Response

    ERIC Educational Resources Information Center

    James, David V. B.; Munson, Steven C.; Maldonado-Martin, Sara; De Ste Croix, Mark B. A.

    2012-01-01

    The purpose of the present study was to investigate the influence of two exercise intensities (moderate and severe) on heart rate variability (HRV) response in 16 runners 1 hr prior to (-1 hr) and at +1 hr, +24 hr, +48 hr, and +72 hr following each exercise session. Time domain indexes and a high frequency component showed a significant decrease…

  15. Heart Rate Variability During Early Adaptation to Space

    NASA Technical Reports Server (NTRS)

    Toscano, W. B.; Cowings, P. S.

    1994-01-01

    A recent report hypothesized that episodes of space motion sickness (SMS) were reliably associated with low frequency oscillations (less than 0.03 to less than 0.01 Hz) in heart rate variability. This paper archives a large data set for review of investigators in this field which may facilitate the evaluation of this hypothesis. Continuous recording of Electro-cardiography (ECG) and other measures were made for 6 to 12 hours per day (waking hours) of six Shuttle crewmembers for the first 3 mission days of two separate Shuttle flights. Spectral analyses of heart rate variability during approximately 200 hours of inflight is presented. In addition, nearly 200 hours of data collected on these same individuals during ground tests prior to the mission are presented. The Purpose of this Publication is to document the incidence of low frequency oscillations of heart rate in 4 people exposed to microgravity over a period of five days. In addition, this report contains spectral analyses of heart rate data collected on these same individuals during ground-based mission simulations. By archiving these data in this manner, it is our intention to make this information available to other investigators interested in studying this phenomena.

  16. Heart Rate and Stress in a College Setting

    ERIC Educational Resources Information Center

    Elwess, Nancy L.; Vogt, F. Daniel

    2005-01-01

    Conditions producing stress are present in all colleges and universities. In this paper we report on an investigation utilizing heart rate as an indicator of stress in students when participating in activities encountered in a college classroom or laboratory. The activities included presenting an oral report, taking an exam, and participating in a…

  17. Heart Rate Monitors Promote Physical Education for Children

    ERIC Educational Resources Information Center

    Tipton, Jan; Sander, Allan N.

    2004-01-01

    National health and fitness data suggests that a significant percentage of children are not on a pathway to leading healthy, physically active lifestyles. Many children are leading sedentary lifestyles due to a lack of opportunity, success, or self-motivation in physical activity. Programs that highlight the use of heart rate monitors offer a…

  18. [Analysing heart rate variability to improve the monitoring of pain].

    PubMed

    Butruille, Laura; De Jonckheere, Julien; Jeanne, Mathieu; Tavernier, Benoît; Logier, Régis

    2016-12-01

    An innovative technique based on the analysis of instantaneous heart rate variability helps to improve the prevention and management of pain and discomfort. Simple to implement, this non-invasive technique is based on the continuous recording of the electrocardiograph signal. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  19. Measuring task-related changes in heart rate variability.

    PubMed

    Moses, Ziev B; Luecken, Linda J; Eason, James C

    2007-01-01

    Small beat-to-beat differences in heart rate are the result of dynamic control of the cardiovascular system by the sympathetic and parasympathetic nervous systems. Heart rate variability (HRV) has been positively correlated with both mental and physical health. While many studies measure HRV under rest conditions, few have measured HRV during stressful situations. We describe an experimental protocol designed to measure baseline, task, and recovery values of HRV as a function of three different types of stressors. These stressors involve an attention task, a cold pressor test, and a videotaped speech presentation. We found a measurable change in heart rate in participants (n=10) during each task (all p's < 0.05). The relative increase or decrease from pre-task heart rate was predicted by task (one-way ANOVA, p= 0.0001). Spectral analysis of HRV during the attention task revealed consistently decreased measures of both high (68+/-7%, mean+/-S.E.) and low (62+/-13%) frequency HRV components as compared to baseline. HRV spectra for the cold pressor and speech tasks revealed no consistent patterns of increase or decrease from baseline measurements. We also found no correlation in reactivity measures between any of our tasks. These findings suggest that each of the tasks in our experimental design elicits a different type of stress response in an individual. Our experimental approach may prove useful to biobehavioral researchers searching for factors that determine individual differences in responses to stress in daily life.

  20. Adaptation of autonomic heart rate regulation in astronauts after spaceflight

    PubMed Central

    Vandeput, Steven; Widjaja, Devy; Aubert, Andre E.; Van Huffel, Sabine

    2013-01-01

    Background Spaceflight causes changes in the cardiovascular control system. The aim of this study was to evaluate postflight recovery of linear and nonlinear neural markers of heart rate modulation, with a special focus on day-night variations. Material/Methods Twenty-four-hour Holter ECG recordings were obtained in 8 astronauts participating in space missions aboard the International Space Station (ISS). Data recording was performed 1 month before launch, and 5 and 30 days after return to Earth from short- and long-term flights. Cardiovascular control was inferred from linear and nonlinear heart rate variability (HRV) parameters, separately during 2-hour day and 2-hour night recordings. Results No remarkable differences were found in the postflight recovery between astronauts from short- and long-duration spaceflights. Five days after return to Earth, vagal modulation was significantly decreased compared to the preflight condition (day: p=0.001; night: p=0.019), while the sympathovagal balance was strongly increased, but only at night (p=0.017). A few nonlinear parameters were reduced early postflight compared to preflight values, but these were not always statistically significant. No significant differences remained after 30 days of postflight recovery. Conclusions Our results show that 5 days after return from both short- and long-duration space missions, neural mechanisms of heart rate regulation are still disturbed. After 1 month, autonomic control of heart rate recovered almost completely. PMID:23291736

  1. Exercise blood pressure and heart rate reference values.

    PubMed

    Gläser, Sven; Friedrich, Nele; Koch, Beate; Schäper, Christoph; Völzke, Henry; Felix, Stephan B; Empen, Klaus; Hannemann, Anke; Ewert, Ralf; Dörr, Marcus

    2013-08-01

    Besides their prognostic impact blood pressure and peak heart rate are widely used endpoint parameters for incremental exercise tests. Reference equations and ranges on both are sparse. This study aims to describe prediction equations and reference ranges for systolic and diastolic blood pressure as well as for peak heart rate assessed during a symptom limited incremental exercise test based on a population based study--the Study of Health in Pomerania. For this purpose, 1708 individuals aged 25-85 years underwent cardiopulmonary exercise testing. After exclusion of subjects with cardiopulmonary diseases and antihypertensive medications regression analyses revealed age, sex and body mass index as statistically significant interfering factors. In accordance, prediction equations and reference ranges for blood pressure and peak heart rate with respect to sex, age and BMI have been established. This study provides a reliable set of prediction equations for blood pressure and heart rate values at peak exercise, assessed in a general population over a wide age range. Copyright © 2013 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  2. Relationship between Exercise Heart Rate and Music Tempo Preference

    ERIC Educational Resources Information Center

    Karageorghis, Costas I.; Jones, Leighton; Low, Daniel C.

    2006-01-01

    The present study examined the predicted positive and linear relationship (Iwanaga, 1995a, 1995b) between exercise heart rate and music tempo preference. Initially, 128 undergraduate students (M age = 20.0 years, SD = 0.9) were surveyed to establish their three favorite music artists. A separate experimental group of 29 undergraduates (M age =…

  3. Heart Rate Variability During Early Adaptation to Space

    NASA Technical Reports Server (NTRS)

    Toscano, W. B.; Cowings, P. S.

    1994-01-01

    A recent report hypothesized that episodes of space motion sickness (SMS) were reliably associated with low frequency oscillations (less than 0.03 to less than 0.01 Hz) in heart rate variability. This paper archives a large data set for review of investigators in this field which may facilitate the evaluation of this hypothesis. Continuous recording of Electro-cardiography (ECG) and other measures were made for 6 to 12 hours per day (waking hours) of six Shuttle crewmembers for the first 3 mission days of two separate Shuttle flights. Spectral analyses of heart rate variability during approximately 200 hours of inflight is presented. In addition, nearly 200 hours of data collected on these same individuals during ground tests prior to the mission are presented. The Purpose of this Publication is to document the incidence of low frequency oscillations of heart rate in 4 people exposed to microgravity over a period of five days. In addition, this report contains spectral analyses of heart rate data collected on these same individuals during ground-based mission simulations. By archiving these data in this manner, it is our intention to make this information available to other investigators interested in studying this phenomena.

  4. Volitional Control of Heart Rate During Exercise Stress.

    ERIC Educational Resources Information Center

    LeFevers, Victoria A.

    Thirty five volunteer college women were divided into three groups to determine if heart rate could be conditioned instrumentally and lowered during exercise stress on the treadmill. The three groups were a) experimental group I, 15 subjects who received instrumental conditioning with visual feedback; b) instrumental group II, 9 subjects who…

  5. Volitional Control of Heart Rate During Exercise Stress.

    ERIC Educational Resources Information Center

    LeFevers, Victoria A.

    Thirty five volunteer college women were divided into three groups to determine if heart rate could be conditioned instrumentally and lowered during exercise stress on the treadmill. The three groups were a) experimental group I, 15 subjects who received instrumental conditioning with visual feedback; b) instrumental group II, 9 subjects who…

  6. An improved method of measuring heart rate using a webcam

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Ouyang, Jianfei; Yan, Yonggang

    2014-09-01

    Measuring heart rate traditionally requires special equipment and physical contact with the subject. Reliable non-contact and low-cost measurements are highly desirable for convenient and comfortable physiological self-assessment. Previous work has shown that consumer-grade cameras can provide useful signals for remote heart rate measurements. In this paper a simple and robust method of measuring the heart rate using low-cost webcam is proposed. Blood volume pulse is extracted by proper Region of Interest (ROI) and color channel selection from image sequences of human faces without complex computation. Heart rate is subsequently quantified by spectrum analysis. The method is successfully applied under natural lighting conditions. Results of experiments show that it takes less time, is much simpler, and has similar accuracy to the previously published and widely used method of Independent Component Analysis (ICA). Benefitting from non-contact, convenience, and low-costs, it provides great promise for popularization of home healthcare and can further be applied to biomedical research.

  7. Exploring the Relationship between Fetal Heart Rate and Cognition

    ERIC Educational Resources Information Center

    Kisilevsky, Barbara S.; Hains, Sylvia M. J.

    2010-01-01

    A relationship between fetal heart rate (HR) and cognition is explored within the context of infant, child and adult studies where the association is well established. Lack of direct access to the fetus and maturational changes limit research paradigms and response measures for fetal studies. Nevertheless, neural regulation of HR shows a number of…

  8. Heart Rate Monitors Promote Physical Education for Children

    ERIC Educational Resources Information Center

    Tipton, Jan; Sander, Allan N.

    2004-01-01

    National health and fitness data suggests that a significant percentage of children are not on a pathway to leading healthy, physically active lifestyles. Many children are leading sedentary lifestyles due to a lack of opportunity, success, or self-motivation in physical activity. Programs that highlight the use of heart rate monitors offer a…

  9. Relationship between Exercise Heart Rate and Music Tempo Preference

    ERIC Educational Resources Information Center

    Karageorghis, Costas I.; Jones, Leighton; Low, Daniel C.

    2006-01-01

    The present study examined the predicted positive and linear relationship (Iwanaga, 1995a, 1995b) between exercise heart rate and music tempo preference. Initially, 128 undergraduate students (M age = 20.0 years, SD = 0.9) were surveyed to establish their three favorite music artists. A separate experimental group of 29 undergraduates (M age =…

  10. Infant Heart Rate: A Review of Research and Methodology.

    ERIC Educational Resources Information Center

    Von Bargen, Donna M.

    1983-01-01

    Reviews literature on children up to age one to determine whether heart rate (HR) is a reliable, stable, and valid measure. Considers factors influencing resting HR and the Law of Initial Values, discusses information about response to stimulation and infant perception and affect obtained by using HR measures, and describes HR use in risk…

  11. Heart Rate Variability and Drawing Impairment in Hypoxemic COPD

    ERIC Educational Resources Information Center

    Incalzi, Raffaele Antonelli; Corsonello, Andrea; Trojano, Luigi; Pedone, Claudio; Acanfora, Domenico; Spada, Aldo; D'Addio, Gianni; Maestri, Roberto; Rengo, Franco; Rengo, Giuseppe

    2009-01-01

    We studied 54 patients with hypoxemic chronic obstructive pulmonary disease (COPD). The Mini Mental State Examination and the Mental Deterioration Battery were used for neuropsychological assessment. Heart rate variability (HRV) was assessed based on 24-h Holter ECG recording. Mann-Whitney test was used to compare HRV parameters of patients…

  12. Hierarchical structure in healthy and diseased human heart rate variability

    NASA Astrophysics Data System (ADS)

    Ching, Emily S.; Lin, D. C.; Zhang, C.

    2004-05-01

    It is shown that the healthy and diseased human heart rate variability (HRV) possesses a hierarchical structure of the She-Leveque (SL) form. This structure, first found in measurements in turbulent fluid flows, implies further details in the HRV multifractal scaling. The potential of diagnosis is also discussed based on the characteristics derived from the SL hierarchy.

  13. Exploring the Relationship between Fetal Heart Rate and Cognition

    ERIC Educational Resources Information Center

    Kisilevsky, Barbara S.; Hains, Sylvia M. J.

    2010-01-01

    A relationship between fetal heart rate (HR) and cognition is explored within the context of infant, child and adult studies where the association is well established. Lack of direct access to the fetus and maturational changes limit research paradigms and response measures for fetal studies. Nevertheless, neural regulation of HR shows a number of…

  14. Fetal heart rate changes associated with general anesthesia.

    PubMed

    Fedorkow, D M; Stewart, T J; Parboosingh, J

    1989-07-01

    Decreased fetal heart rate variability was noted 90 seconds after the induction of general anesthesia with sodium thiopentone and fentanyl in a patient undergoing basket extraction of a renal calculus at 30 weeks' gestation. The fetal sleep pattern lasted for 105 minutes after the anesthetic was discontinued, 45 minutes after the mother was fully awake.

  15. Heart Rate Variability and Drawing Impairment in Hypoxemic COPD

    ERIC Educational Resources Information Center

    Incalzi, Raffaele Antonelli; Corsonello, Andrea; Trojano, Luigi; Pedone, Claudio; Acanfora, Domenico; Spada, Aldo; D'Addio, Gianni; Maestri, Roberto; Rengo, Franco; Rengo, Giuseppe

    2009-01-01

    We studied 54 patients with hypoxemic chronic obstructive pulmonary disease (COPD). The Mini Mental State Examination and the Mental Deterioration Battery were used for neuropsychological assessment. Heart rate variability (HRV) was assessed based on 24-h Holter ECG recording. Mann-Whitney test was used to compare HRV parameters of patients…

  16. Heart Rate Variability: Effect of Exercise Intensity on Postexercise Response

    ERIC Educational Resources Information Center

    James, David V. B.; Munson, Steven C.; Maldonado-Martin, Sara; De Ste Croix, Mark B. A.

    2012-01-01

    The purpose of the present study was to investigate the influence of two exercise intensities (moderate and severe) on heart rate variability (HRV) response in 16 runners 1 hr prior to (-1 hr) and at +1 hr, +24 hr, +48 hr, and +72 hr following each exercise session. Time domain indexes and a high frequency component showed a significant decrease…

  17. A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability

    PubMed Central

    Shaffer, Fred; McCraty, Rollin; Zerr, Christopher L.

    2014-01-01

    Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges' polyvagal theory, Thayer and colleagues' neurovisceral integration model, Lehrer et al.'s resonance frequency model, and the Institute of HeartMath's coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain. PMID:25324790

  18. Development of multiscale complexity and multifractality of fetal heart rate variability.

    PubMed

    Gierałtowski, Jan; Hoyer, Dirk; Tetschke, Florian; Nowack, Samuel; Schneider, Uwe; Zebrowski, Jan

    2013-11-01

    During fetal development a complex system grows and coordination over multiple time scales is formed towards an integrated behavior of the organism. Since essential cardiovascular and associated coordination is mediated by the autonomic nervous system (ANS) and the ANS activity is reflected in recordable heart rate patterns, multiscale heart rate analysis is a tool predestined for the diagnosis of prenatal maturation. The analyses over multiple time scales requires sufficiently long data sets while the recordings of fetal heart rate as well as the behavioral states studied are themselves short. Care must be taken that the analysis methods used are appropriate for short data lengths. We investigated multiscale entropy and multifractal scaling exponents from 30 minute recordings of 27 normal fetuses, aged between 23 and 38 weeks of gestational age (WGA) during the quiet state. In multiscale entropy, we found complexity lower than that of non-correlated white noise over all 20 coarse graining time scales investigated. Significant maturation age related complexity increase was strongest expressed at scale 2, both using sample entropy and generalized mutual information as complexity estimates. Multiscale multifractal analysis (MMA) in which the Hurst surface h(q,s) is calculated, where q is the multifractal parameter and s is the scale, was applied to the fetal heart rate data. MMA is a method derived from detrended fluctuation analysis (DFA). We modified the base algorithm of MMA to be applicable for short time series analysis using overlapping data windows and a reduction of the scale range. We looked for such q and s for which the Hurst exponent h(q,s) is most correlated with gestational age. We used this value of the Hurst exponent to predict the gestational age based only on fetal heart rate variability properties. Comparison with the true age of the fetus gave satisfying results (error 2.17±3.29 weeks; p<0.001; R(2)=0.52). In addition, we found that the normally

  19. Effects of biofeedback training on voluntary heart rate control during dynamic exercise.

    PubMed

    Alvarez Moleiro, M; Villamaín Cid, F

    2001-12-01

    The aims of this study were to (1) compare the effect of biofeedback with that of verbal instructions on the control of heart rate during exercise on a treadmill, (2) test the possible effect of workload on this control, and (3) examine the effect of workload on baseline heart rate at rest and during exercise. The study involved 35 participants who were randomly assigned to each of 4 experimental conditions generated by combining the 2 independent variables: training strategy for heart rate control (heart rate biofeedback or verbal control instructions) and work level (30 or 50% of maximal heart rate). By the end of 5 experimental sessions, participants trained with heart rate biofeedback showed a greater attenuation of the increase in heart rate produced by exercise than participants trained with verbal control instructions. The workload did not influence the voluntary control of heart rate, nor did it affect resting baseline heart rate, but it did affect exercise baseline heart rate.

  20. Effect of Selective Heart Rate Slowing in Heart Failure With Preserved Ejection Fraction.

    PubMed

    Pal, Nikhil; Sivaswamy, Nadiya; Mahmod, Masliza; Yavari, Arash; Rudd, Amelia; Singh, Satnam; Dawson, Dana K; Francis, Jane M; Dwight, Jeremy S; Watkins, Hugh; Neubauer, Stefan; Frenneaux, Michael; Ashrafian, Houman

    2015-11-03

    Heart failure with preserved ejection fraction (HFpEF) is associated with significant morbidity and mortality but is currently refractory to therapy. Despite limited evidence, heart rate reduction has been advocated, on the basis of physiological considerations, as a therapeutic strategy in HFpEF. We tested the hypothesis that heart rate reduction improves exercise capacity in HFpEF. We conducted a randomized, crossover study comparing selective heart rate reduction with the If blocker ivabradine at 7.5 mg twice daily versus placebo for 2 weeks each in 22 symptomatic patients with HFpEF who had objective evidence of exercise limitation (peak oxygen consumption at maximal exercise [o2 peak] <80% predicted for age and sex). The result was compared with 22 similarly treated matched asymptomatic hypertensive volunteers. The primary end point was the change in o2 peak. Secondary outcomes included tissue Doppler-derived E/e' at echocardiography, plasma brain natriuretic peptide, and quality-of-life scores. Ivabradine significantly reduced peak heart rate compared with placebo in the HFpEF (107 versus 129 bpm; P<0.0001) and hypertensive (127 versus 145 bpm; P=0.003) cohorts. Ivabradine compared with placebo significantly worsened the change in o2 peak in the HFpEF cohort (-2.1 versus 0.9 mL·kg(-1)·min(-1); P=0.003) and significantly reduced submaximal exercise capacity, as determined by the oxygen uptake efficiency slope. No significant effects on the secondary end points were discernable. Our observations bring into question the value of heart rate reduction with ivabradine for improving symptoms in a HFpEF population characterized by exercise limitation. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02354573. © 2015 The Authors.

  1. Effect of Selective Heart Rate Slowing in Heart Failure With Preserved Ejection Fraction

    PubMed Central

    Pal, Nikhil; Sivaswamy, Nadiya; Mahmod, Masliza; Yavari, Arash; Rudd, Amelia; Singh, Satnam; Dawson, Dana K.; Francis, Jane M.; Dwight, Jeremy S.; Watkins, Hugh; Neubauer, Stefan; Frenneaux, Michael

    2015-01-01

    Background— Heart failure with preserved ejection fraction (HFpEF) is associated with significant morbidity and mortality but is currently refractory to therapy. Despite limited evidence, heart rate reduction has been advocated, on the basis of physiological considerations, as a therapeutic strategy in HFpEF. We tested the hypothesis that heart rate reduction improves exercise capacity in HFpEF. Methods and Results— We conducted a randomized, crossover study comparing selective heart rate reduction with the If blocker ivabradine at 7.5 mg twice daily versus placebo for 2 weeks each in 22 symptomatic patients with HFpEF who had objective evidence of exercise limitation (peak oxygen consumption at maximal exercise [o2 peak] <80% predicted for age and sex). The result was compared with 22 similarly treated matched asymptomatic hypertensive volunteers. The primary end point was the change in o2 peak. Secondary outcomes included tissue Doppler–derived E/e′ at echocardiography, plasma brain natriuretic peptide, and quality-of-life scores. Ivabradine significantly reduced peak heart rate compared with placebo in the HFpEF (107 versus 129 bpm; P<0.0001) and hypertensive (127 versus 145 bpm; P=0.003) cohorts. Ivabradine compared with placebo significantly worsened the change in o2 peak in the HFpEF cohort (-2.1 versus 0.9 mL·kg−1·min−1; P=0.003) and significantly reduced submaximal exercise capacity, as determined by the oxygen uptake efficiency slope. No significant effects on the secondary end points were discernable. Conclusion— Our observations bring into question the value of heart rate reduction with ivabradine for improving symptoms in a HFpEF population characterized by exercise limitation. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT02354573. PMID:26338956

  2. Music structure determines heart rate variability of singers

    PubMed Central

    Vickhoff, Björn; Malmgren, Helge; Åström, Rickard; Nyberg, Gunnar; Ekström, Seth-Reino; Engwall, Mathias; Snygg, Johan; Nilsson, Michael; Jörnsten, Rebecka

    2013-01-01

    Choir singing is known to promote wellbeing. One reason for this may be that singing demands a slower than normal respiration, which may in turn affect heart activity. Coupling of heart rate variability (HRV) to respiration is called Respiratory sinus arrhythmia (RSA). This coupling has a subjective as well as a biologically soothing effect, and it is beneficial for cardiovascular function. RSA is seen to be more marked during slow-paced breathing and at lower respiration rates (0.1 Hz and below). In this study, we investigate how singing, which is a form of guided breathing, affects HRV and RSA. The study comprises a group of healthy 18 year olds of mixed gender. The subjects are asked to; (1) hum a single tone and breathe whenever they need to; (2) sing a hymn with free, unguided breathing; and (3) sing a slow mantra and breathe solely between phrases. Heart rate (HR) is measured continuously during the study. The study design makes it possible to compare above three levels of song structure. In a separate case study, we examine five individuals performing singing tasks (1–3). We collect data with more advanced equipment, simultaneously recording HR, respiration, skin conductance and finger temperature. We show how song structure, respiration and HR are connected. Unison singing of regular song structures makes the hearts of the singers accelerate and decelerate simultaneously. Implications concerning the effect on wellbeing and health are discussed as well as the question how this inner entrainment may affect perception and behavior. PMID:23847555

  3. Increased heart rate variability but normal resting metabolic rate in hypocretin/orexin-deficient human narcolepsy.

    PubMed

    Fronczek, Rolf; Overeem, Sebastiaan; Reijntjes, Robert; Lammers, Gert Jan; van Dijk, J Gert; Pijl, Hanno

    2008-06-15

    We investigated autonomic balance and resting metabolic rate to explore their possible involvement in obesity in hypocretin/orexin-deficient narcoleptic subjects. Resting metabolic rate (using indirect calorimetry) and variability in heart rate and blood pressure were determined in the fasted resting state. Subjects included 15 untreated, hypocretin-deficient male narcoleptics and 15 male controls matched for age and body mass index. Spectral power analysis revealed greater heart rate and blood pressure variability in hypocretin-deficient male narcoleptic patients (heart rate: p = 0.01; systolic blood pressure: p = 0.02; diastolic: p < 0.01). The low to high frequency ratio of heart rate power did not differ between groups (p = 0.48), nor did resting metabolic rate (controls: 1767 +/- 226 kcal/24 h; patients: 1766 +/- 227 kcal/24h; p = 0.99). Resting metabolic rate was not reduced in hypocretin-deficient narcoleptic men and therefore does not explain obesity in this group. Whether the increased heart rate and blood pressure variability--suggesting reduced sympathetic tone--is involved in this regard remains to be elucidated.

  4. Resting Heart Rate and Long-Term Outcomes Among African Americans: Insights From the Jackson Heart Study

    PubMed Central

    Parikh, Kishan S.; Greiner, Melissa A.; Suzuki, Takeki; DeVore, Adam D.; Blackshear, Chad; Maher, Joseph F.; Curtis, Lesley H.; Hernandez, Adrian F.; O’Brien, Emily C.; Mentz, Robert J.

    2016-01-01

    Importance Increased resting heart rate is associated with worse outcomes in studies of mostly white populations, but its significance is not well established in African Americans whose cardiac comorbidities and structural abnormalities differ. Objective We studied the prognostic utility of heart rate in a community-based African American cohort in Jackson, Mississippi. Design We included 5261 participants in the Jackson Heart Study. Baseline heart rate was assessed by quintiles and as a continuous variable. Study follow-up was greater than 7 years and started in 2000. Setting The Jackson Heart Study, a prospective, community-based study in Jackson, Mississippi. Participants All participants with baseline heart rate documented by 12-lead electrocardiogram without pacing or atrial fibrillation on their baseline Jackson Heart Study exam were included in our study. Main Outcomes and Measures We estimated unadjusted and adjusted associations between heart rate and all-cause mortality and heart failure hospitalization using Cox proportional hazards models. Results Median baseline heart rate was 63 bpm (interquartile range, 57–71 bpm). The highest heart rate quintile (73–118 bpm) included more women, higher rates of diabetes and hypertension, higher body mass index, less average activity, and lower β-blocker use compared with lower quintiles. Caffeine intake and ejection fraction were similar between groups. As a continuous variable, elevated heart rate was associated with increased mortality and heart failure hospitalizations with adjusted hazard ratios for every 5 bpm increase of 1.14 (95% CI, 1.10–1.19) and 1.10 (95% CI, 1.05–1.16), respectively. Similar patterns were observed in comparisons between highest and lowest quintiles. Conclusions and Relevance Higher baseline heart rate was associated with increased mortality and heart failure hospitalizations among African Americans in the Jackson Heart Study. PMID:27681113

  5. Assessing heart rate variability from real-world Holter reports.

    PubMed

    Stein, Phyllis K

    2002-09-01

    Real world clinical Holter reports are often difficult to interpret from a heart rate variability (HRV) perspective. In many cases HRV software is absent. Step-by-step HRV assessment from clinical Holter reports includes: making sure that there is enough usable data, assessing maximum and minimum heart rates, assessing circadian HRV from hourly average heart rates, and assessing HRV from the histogram of R-R intervals and from the plot of R-R intervals or heart rate vs. time. If HRV data are available, time domain HRV is easiest to understand and less sensitive to scanning errors. SDNN (the standard deviation of all N-N intervals in ms) and SDANN (the standard deviation of the 5-min average of N-N intervals in ms) are easily interpreted. SDNN < 70 ms post-MI is a cut point for increased mortality risk. Two times ln SDANN is a good surrogate for ln ultra low frequency power and can be compared with published cut points. SDNNIDX (the average of the standard deviations of N-N intervals for each 5-min in ms) < 30 ms is associated with increased risk in patients with congestive heart failure. RMSSD (the root mean square of successive N-N interval difference in ms) < 17.5 ms has also been associated with increased risk post-myocardial infarction. Frequency domain HRV values are often not comparable to published data. However, graphical power spectral plots can provide additional information about whether the HRV pattern is normal and can also identify some patients with obstructive sleep apnea.

  6. [Resting heart rate in subjects with carbohydrate disorders].

    PubMed

    Kowalski, Jan; Brylik, Anna; Irzmański, Robert; Pawlicki, Lucjan; Ciećwierz, Julita; Jarzabek, Krzysztof; Barylski, Marcin

    2012-02-01

    Large epidemiological studies conducted during last 25 years confirmed the importance of resting heart rate as an independent risk factor for total and cardiovascular mortality in females and males, both in overall population and in subjects with cardiovascular diseases such as arterial hypertension, myocardial infarction, coronary heart disease, heart failure or left ventricular dysfunction. The aim of the study was to evaluate the resting heart rate (HR) in subjects with carbohydrate disorders. The study comprised 112 subjects with carbohydrate disorders (54 females and 58 males), aged 30-78 (57.4 +/- 9.6) years. Carbohydrate disorders were diagnosed according to the Polish Diabetes Association criteria from 2007 (group I). 56 subjects had impaired fasting glucose (IFG), 36 - impaired glucose tolerance (IGT) and 20 - type 2 diabetes. Comparative group comprised 30 subjects without cardiovascular diseases and carbohydrate disorders (15 females and 15 males), aged 29-64 (52.7 +/- 8.8) years (group II). The fasting serum glucose level was evaluated using an enzymatic method, Kone Pro biochemical analyzer and bioMérieux Glucose RTU kit. In subjects with fasting glucose level > or = 100 mg/dl, an oral glucose tolerance test (OGTT) was performed. Additionally, in all subjects resting heart rate (HR) was measured, after 10-minute rest, at a room temperature of about 20 degrees C. The measurements were made threefold, every 5 minutes and mean value was assessed. In subjects with carbohydrate disorders HR was significantly higher than in comparative group (82.79 +/- 12.1 vs 69.9 +/- 9.56/min; p < 0.05). In group of subjects with carbohydrate disorders in comparison to comparative group, resting heart rate < 60/min occurred in 1.79 vs 13.33%, in intervals: 60-70/min in 14.29 vs 50%. 71-80/min in 33.93 vs 23.33%, 81-90/min in 25% vs 13.33%, and above 90/min in 25% of studied group (p < 0.05). On the basis of ROC curve analysis and odds ratio (OR) it was shown that HR > or

  7. Improved ultrasound transducer positioning by fetal heart location estimation during Doppler based heart rate measurements.

    PubMed

    Hamelmann, Paul; Vullings, Rik; Schmitt, Lars; Kolen, Alexander Franciscus; Mischi, Massimo; Van Laar, Judith O E H; Bergmans, Jan W M

    2017-09-04

    Doppler Ultrasound (US) is the most commonly applied method to measure the fetal heart rate (fHR). When the fetal heart is not properly located within the ultrasonic beam, fHR measurements often fail. As a consequence, clinical staff needs to reposition the US transducer on the maternal abdomen, which can be a time consuming and tedious task. In this article, a method is presented to aid clinicians with the positioning of the US transducer to produce robust fHR measurements. A maximum likelihood estimation (MLE) algorithm is developed, which provides information on fetal heart location using the power of the Doppler signals received in the individual elements of a standard US transducer for fHR recordings. The performance of the algorithm is evaluated with simulations and in-vitro experiments performed on a beating-heart setup. Both the experiments and the simulations show that the heart location can be accurately determined with an error of less than 7 mm within the measurement volume of the employed US transducer. The results show that the developed algorithm can be used to provide accurate feedback on fetal heart location for improved positioning of the US transducer, which may lead to improved measurements of the fHR. © 2017 Institute of Physics and Engineering in Medicine.

  8. Pulse transducer with artifact signal attenuator. [heart rate sensors

    NASA Technical Reports Server (NTRS)

    Cash, W. H., Jr.; Polhemus, J. T. (Inventor)

    1980-01-01

    An artifact signal attenuator for a pulse rate sensor is described. The circuit for attenuating background noise signals is connected with a pulse rate transducer which has a light source and a detector for light reflected from blood vessels of a living body. The heart signal provided consists of a modulated dc signal voltage indicative of pulse rate. The artifact signal resulting from light reflected from the skin of the body comprises both a constant dc signal voltage and a modulated dc signal voltage. The amplitude of the artifact signal is greater and the frequency less than that of the heart signal. The signal attenuator circuit includes an operational amplifier for canceling the artifact signal from the output signal of the transducer and has the capability of meeting packaging requirements for wrist-watch-size packages.

  9. Regulation of heart rate and rumen temperature in red deer: effects of season and food intake

    PubMed Central

    Turbill, Christopher; Ruf, Thomas; Mang, Thomas; Arnold, Walter

    2012-01-01

    SUMMARY Red deer, Cervus elaphus, like other temperate-zone animals, show a large seasonal fluctuation in energy intake and expenditure. Many seasonal phenotypic adjustments are coordinated by endogenous signals entrained to the photoperiod. The cues determining variation in the resting metabolism of ungulates remain equivocal, however, largely because of the confounding effects of food intake and thus the heat increment of feeding. To distinguish endogenous seasonal and environmental effects on metabolism, we subjected 15 female red deer to two feeding treatments, 80% food restriction and low/high protein content, over two winter seasons in a cross-over design experiment. We used rumen-located transmitters to measure heart rate and rumen temperature, which provided indices of metabolism and core body temperature, respectively. Our mixed model (R2=0.85) indicated a residual seasonal effect on mean daily heart rate that was unexplained by the pellet food treatments, activity, body mass or air temperature. In addition to an apparently endogenous down-regulation of heart rate in winter, the deer further reduced heart rate over about 8 days in response to food restriction. We found a strong correlation between rumen temperature and seasonal or periodic variation in heart rate. An effect of lowered rumen (and hence core body) temperature was enhanced during winter, perhaps owing to peripheral cooling, which is known to accompany bouts of hypometabolism. Our experimental results therefore support the hypothesis that a reduction in body temperature is a physiological mechanism employed even by large mammals, like red deer, to reduce their energy expenditure during periods of negative energy balance. PMID:21346124

  10. Regulation of heart rate and rumen temperature in red deer: effects of season and food intake.

    PubMed

    Turbill, Christopher; Ruf, Thomas; Mang, Thomas; Arnold, Walter

    2011-03-15

    Red deer, Cervus elaphus, like other temperate-zone animals, show a large seasonal fluctuation in energy intake and expenditure. Many seasonal phenotypic adjustments are coordinated by endogenous signals entrained to the photoperiod. The cues determining variation in the resting metabolism of ungulates remain equivocal, however, largely because of the confounding effects of food intake and thus the heat increment of feeding. To distinguish endogenous seasonal and environmental effects on metabolism, we subjected 15 female red deer to two feeding treatments, 80% food restriction and low/high protein content, over two winter seasons in a cross-over design experiment. We used rumen-located transmitters to measure heart rate and rumen temperature, which provided indices of metabolism and core body temperature, respectively. Our mixed model (R²=0.85) indicated a residual seasonal effect on mean daily heart rate that was unexplained by the pellet food treatments, activity, body mass or air temperature. In addition to an apparently endogenous down-regulation of heart rate in winter, the deer further reduced heart rate over about 8 days in response to food restriction. We found a strong correlation between rumen temperature and seasonal or periodic variation in heart rate. An effect of lowered rumen (and hence core body) temperature was enhanced during winter, perhaps owing to peripheral cooling, which is known to accompany bouts of hypometabolism. Our experimental results therefore support the hypothesis that a reduction in body temperature is a physiological mechanism employed even by large mammals, like red deer, to reduce their energy expenditure during periods of negative energy balance.

  11. Abnormal heart rate recovery on exercise in ankylosing spondylitis.

    PubMed

    Kaya, Mehmet G; Akpek, Mahmut; Lam, Yat-Yin; Dogdu, Orhan; Ardic, Idris; Akgul, Ozgur; Ozgocmen, Salih

    2013-11-05

    This study evaluated the heart rate recovery response in ankylosing spondylitis (AS) patients and control subjects. Delayed heart rate recovery after exercise reflects AD and independently predicts adverse cardiac outcome. Fifty-one patients with AS and 50 age- and matched controls received electrocardiography, echocardiography, and treadmill exercise testing. The heart rate recovery (HRR) index was calculated as the reduction in heart rate from the rate at peak exercise to the rate at the 1st (HRR1), 2nd (HRR2), 3rd (HRR3) and 5th (HRR5) minute after the cessation of exercise stress testing. There were significant differences in HRR1 and HRR2 indices between patients and controls (24.8 ± 12.1 vs 34.9 ± 11.0; p<0.001 and 41.2 ± 14.2 vs 54.3 ± 11.8; p<0.001, beats/min, respectively). Similarly, HRR3 and HRR5 indices were lower in patients than controls (51.3 ± 15.1 vs 65.2 ± 14.0; p<0.001 and 61.0 ± 14.2 vs 76.1 ± 14.8; p<0.001). In addition, exercise capacity was markedly lower (8.1 ± 2.0 vs 10.5 ± 2.5 METs; p<0.001) in AS than controls. The HRR index is impaired in AS patients, implying the occurrence of autonomic dysfunction even without active joint disease or frank cardiac involvement. © 2013.

  12. Mind and heart: heart rate variability in major depressive disorder and coronary heart disease - a review and recommendations.

    PubMed

    Stapelberg, Nicolas J; Hamilton-Craig, Ian; Neumann, David L; Shum, David H K; McConnell, Harry

    2012-10-01

    There is a reciprocal association between major depressive disorder (MDD) and coronary heart disease (CHD). These conditions are linked by a causal network of mechanisms. This causal network should be quantitatively studied and it is hypothesised that the investigation of vagal function represents a promising starting point. Heart rate variability (HRV) has been used to investigate cardiac vagal control in the context of MDD and CHD. This review aims to examine the relationship of HRV to both MDD and CHD in the context of vagal function and to make recommendations for clinical practice and research. The search terms 'heart rate variability', 'depression' and 'heart disease' were entered into an electronic multiple database search engine. Abstracts were screened for their relevance and articles were individually selected and collated. Decreased HRV is found in both MDD and CHD. Both diseases are theorized to disrupt autonomic control feedback loops on the heart and are linked to vagal function. Existing theories link vagal function to both mood and emotion as well as cardiac function. However, several factors can potentially confound HRV measures and would thus impact on a complete understanding of vagal mechanisms in the link between MDD and CHD. The quantitative investigation of vagal function using HRV represents a reasonable starting point in the study of the relationship between MDD and CHD. Many psychotropic and cardiac medications have effects on HRV, which may have clinical importance. Future studies of HRV in MDD and CHD should consider antidepressant medication, as well as anxiety, as potential confounders.

  13. Heart Rate and Heart Rate Variability in Dairy Cows with Different Temperament and Behavioural Reactivity to Humans

    PubMed Central

    Tőzsér, János; Szenci, Ottó; Póti, Péter; Pajor, Ferenc

    2015-01-01

    From the 1990s, extensive research was started on the physiological aspects of individual traits in animals. Previous research has established two extreme (proactive and reactive) coping styles in several animal species, but the means of reactivity with the autonomic nervous system (ANS) activity has not yet been investigated in cattle. The aim of this study was the characterization of cardiac autonomic activity under different conditions in cows with different individual characteristics. For this purpose, we investigated heart rate and ANS-related heart rate variability (HRV) parameters of dairy cows (N = 282) on smaller- and larger-scale farms grouped by (1) temperament and (2) behavioural reactivity to humans (BRH). Animals with high BRH scores were defined as impulsive, while animals with low BRH scores were defined as reserved. Cardiac parameters were calculated for undisturbed lying (baseline) and for milking bouts, the latter with the presence of an unfamiliar person (stressful situation). Sympathetic tone was higher, while vagal activity was lower in temperamental cows than in calm animals during rest both on smaller- and larger-scale farms. During milking, HRV parameters were indicative of a higher sympathetic and a lower vagal activity of temperamental cows as compared to calm ones in farms of both sizes. Basal heart rate did not differ between BRH groups either on smaller- or larger-scale farms. Differences between basal ANS activity of impulsive and reserved cows reflected a higher resting vagal and lower sympathetic activity of reserved animals compared to impulsive ones both on smaller- and larger-scale farms. There was no difference either in heart rate or in HRV parameters between groups during milking neither in smaller- nor in larger-scale farms. These two groupings allowed to draw possible parallels between personality and cardiac autonomic activity during both rest and milking in dairy cows. Heart rate and HRV seem to be useful for

  14. Heart Rate and Heart Rate Variability in Dairy Cows with Different Temperament and Behavioural Reactivity to Humans.

    PubMed

    Kovács, Levente; Kézér, Fruzsina Luca; Tőzsér, János; Szenci, Ottó; Póti, Péter; Pajor, Ferenc

    2015-01-01

    From the 1990s, extensive research was started on the physiological aspects of individual traits in animals. Previous research has established two extreme (proactive and reactive) coping styles in several animal species, but the means of reactivity with the autonomic nervous system (ANS) activity has not yet been investigated in cattle. The aim of this study was the characterization of cardiac autonomic activity under different conditions in cows with different individual characteristics. For this purpose, we investigated heart rate and ANS-related heart rate variability (HRV) parameters of dairy cows (N = 282) on smaller- and larger-scale farms grouped by (1) temperament and (2) behavioural reactivity to humans (BRH). Animals with high BRH scores were defined as impulsive, while animals with low BRH scores were defined as reserved. Cardiac parameters were calculated for undisturbed lying (baseline) and for milking bouts, the latter with the presence of an unfamiliar person (stressful situation). Sympathetic tone was higher, while vagal activity was lower in temperamental cows than in calm animals during rest both on smaller- and larger-scale farms. During milking, HRV parameters were indicative of a higher sympathetic and a lower vagal activity of temperamental cows as compared to calm ones in farms of both sizes. Basal heart rate did not differ between BRH groups either on smaller- or larger-scale farms. Differences between basal ANS activity of impulsive and reserved cows reflected a higher resting vagal and lower sympathetic activity of reserved animals compared to impulsive ones both on smaller- and larger-scale farms. There was no difference either in heart rate or in HRV parameters between groups during milking neither in smaller- nor in larger-scale farms. These two groupings allowed to draw possible parallels between personality and cardiac autonomic activity during both rest and milking in dairy cows. Heart rate and HRV seem to be useful for

  15. Improvements in heart rate variability with exercise therapy

    PubMed Central

    Routledge, Faye S; Campbell, Tavis S; McFetridge-Durdle, Judith A; Bacon, Simon L

    2010-01-01

    Heart rate variability (HRV) is a noninvasive, practical and reproducible measure of autonomic nervous system function. A heart rate that is variable and responsive to demands is believed to bestow a survival advantage, whereas reduced HRV may be associated with poorer cardiovascular health and outcomes. In recent years, many researchers have investigated the prognostic implications of HRV in a variety of clinical populations. Evidence suggests that reduced HRV has prognostic significance for individuals with myocardial infarction, chronic heart failure, unstable angina and diabetes mellitus. Interventions to increase HRV, such as exercise therapy, have also been examined. The findings of the present review suggest that exercise therapy may improve HRV in myocardial infarction, chronic heart failure and revascularization patients by increasing vagal tone and decreasing sympathetic activity. One hypothesis is that a shift toward greater vagal modulation may positively affect the prognosis of these individuals. While the underlying mechanisms by which exercise training improves vagal modulation are speculative at present, angiotensin II and nitric oxide may be potential mediators. PMID:20548976

  16. General anesthesia suppresses normal heart rate variability in humans

    NASA Astrophysics Data System (ADS)

    Matchett, Gerald; Wood, Philip

    2014-06-01

    The human heart normally exhibits robust beat-to-beat heart rate variability (HRV). The loss of this variability is associated with pathology, including disease states such as congestive heart failure (CHF). The effect of general anesthesia on intrinsic HRV is unknown. In this prospective, observational study we enrolled 100 human subjects having elective major surgical procedures under general anesthesia. We recorded continuous heart rate data via continuous electrocardiogram before, during, and after anesthesia, and we assessed HRV of the R-R intervals. We assessed HRV using several common metrics including Detrended Fluctuation Analysis (DFA), Multifractal Analysis, and Multiscale Entropy Analysis. Each of these analyses was done in each of the four clinical phases for each study subject over the course of 24 h: Before anesthesia, during anesthesia, early recovery, and late recovery. On average, we observed a loss of variability on the aforementioned metrics that appeared to correspond to the state of general anesthesia. Following the conclusion of anesthesia, most study subjects appeared to regain their normal HRV, although this did not occur immediately. The resumption of normal HRV was especially delayed on DFA. Qualitatively, the reduction in HRV under anesthesia appears similar to the reduction in HRV observed in CHF. These observations will need to be validated in future studies, and the broader clinical implications of these observations, if any, are unknown.

  17. Slower heart rate and altered rate dependence of ventricular repolarization in patients with lone atrial fibrillation.

    PubMed

    Maury, Philippe; Caudron, Guillaume; Bouisset, Frédéric; Fourcade, Joëlle; Duparc, Alexandre; Mondoly, Pierre; Rollin, Anne; Hascoët, Sébastien; Detis, Nicolas; Cardin, Christelle; Delay, Marc; Lairez, Olivier; Roncalli, Jérome; Galinier, Michel; Carrié, Didier; Elbaz, Meyer; Ferrières, Jean; Fauvel, Jean-Marie; Zimmermann, Marc

    2013-01-01

    Electrophysiological alterations in atrial fibrillation (AF) may be genetically based and may lead to changes in ventricular repolarization. Short QT syndrome is a rare channelopathy with abbreviated ventricular repolarization and a propensity for AF. To determine if minor unrecognized forms of short QT syndrome can explain some cases of lone AF. We prospectively compared QT intervals in 66 patients with idiopathic lone AF and 132 age- and sex-matched controls. QT intervals were measured during sinus rhythm in each of the 12 surface electrocardiogram leads and corrected using Bazett's formula (QTc). QT intervals were also corrected using other formulae. Uncorrected QT and heart rate regression lines were compared between AF patients and controls. AF patients presented with a slower resting heart rate (64 ± 10 beats per minute [bpm] vs 69 ± 9 bpm; P=0.0006). QTc intervals were shorter in AF patients in 11/12 electrocardiogram leads (significant in 7/12, borderline in 2/12; mean QTc 381 ± 21 ms vs 388 ± 22 ms; P=0.02). QTc intervals were also shorter in AF patients, significantly or not, using other correction formulae. For similar heart rates, uncorrected QT intervals were shorter in patients when heart rates were greater than 70 bpm and longer when heart rates were less than 60 bpm. AF patients displayed steeper QT/heart rate regression line slopes than controls (P=0.009). Heart rate is significantly slower and the rate dependence of ventricular repolarization is significantly altered in patients with lone AF compared with controls. Further study is warranted to determine if AF induces subsequent ventricular repolarization changes or if these modifications are caused by an underlying primary electrical disease. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  18. Heart rate variability in neonates of type 1 diabetic pregnancy.

    PubMed

    Russell, Noirin E; Higgins, Mary F; Kinsley, Brendan F; Foley, Michael E; McAuliffe, Fionnuala M

    2016-01-01

    Cardiomyopathy is a common finding in offspring of pre-gestational type 1 diabetic pregnancy. Echocardiographic and biochemical evidence of fetal cardiac dysfunction have also been reported. Studies suggest that offspring of diabetic mothers (ODM) undergo a fetal programming effect due to the hyperglycaemic intrauterine milieu which increases their risk of cardiovascular morbidity in adult life. Decreased neonatal heart rate variability (HRV) has been described in association with in-utero growth restriction, prematurity, sudden infant death syndrome and congenital heart disease. The effect of in-utero exposure to hyperglycaemia in diabetic pregnancy on neonatal HRV is unknown. Our aim was to determine if neonatal HRV differs between normal and diabetic pregnancy. This was a prospective observational study of 38 patients with pregestational type 1 diabetes and 26 controls. HRV assessment was performed using Powerlab (ADI Instruments Ltd). Heart rate variability assessment and cord blood sampling for pH and glucose were performed for all neonates. Maternal glycaemic control was assessed via measurement of glycosylated haemoglobin in each trimester in the diabetic cohort. Neonates of diabetic mothers had evidence of altered heart rate variability, with increased low frequency to high frequency ratio (LF: HF), suggestive of a shift towards sympathetic predominance (p<0.05). This altered HRV was significantly related to fetal acidaemia, cord blood glucose values and maternal glycaemic control during pregnancy (p<0.05). Neonates of pregestational diabetic pregnancy have altered HRV which is related to maternal hyperglycaemia, fetal acidaemia and fetal glycaemia. Exposure of the developing heart to fluctuations in maternal glycaemia with subsequent alterations in HRV may explain why infants of diabetic mothers are at greater risk of cardiovascular disease in later life. Copyright © 2015. Published by Elsevier Ireland Ltd.

  19. Heart Rate Dynamics During A Treadmill Cardiopulmonary Exercise Test in Optimized Beta-Blocked Heart Failure Patients

    PubMed Central

    Carvalho, Vitor Oliveira; Guimarães, Guilherme Veiga; Ciolac, Emmanuel Gomes; Bocchi, Edimar Alcides

    2008-01-01

    BACKGROUND Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS Twenty-five heart failure patients (49±11 years, 76% male), with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS Basal heart rate was lower in heart failure patients (57±3 bpm) compared to controls (89±14 bpm; p<0.0001). Similarly, the peak heart rate (% maximum predicted for age) was lower in HF patients (65.4±11.1%) compared to controls (98.6±2.2; p<0.0001). Maximum respiratory exchange ratio did not differ between the groups (1.2±0.5 for controls and 1.15±1 for heart failure patients; p=0.42). All controls reached the maximum heart rate for their age, while no patients in the heart failure group reached the maximum. Moreover, the % increase of heart rate from rest to peak exercise between heart failure (48±9%) and control (53±8%) was not different (p=0.157). CONCLUSION No patient in the heart failure group reached the maximum heart rate for their age during a treadmill cardiopulmonary exercise test, despite the fact that the percentage increase of heart rate was similar to sedentary normal subjects. A heart rate increase in optimized beta-blocked heart failure patients during cardiopulmonary exercise test over 65% of the

  20. Atrial and ventricular rate response and patterns of heart rate acceleration during maternal-fetal terbutaline treatment of fetal complete heart block.

    PubMed

    Cuneo, Bettina F; Zhao, Hui; Strasburger, Janette F; Ovadia, Marc; Huhta, James C; Wakai, Ronald T

    2007-08-15

    Terbutaline is used to treat fetal bradycardia in the setting of complete heart block (CHB); however, little is known of its effects on atrial and ventricular beat rates or patterns of heart rate (HR) acceleration. Fetal atrial and ventricular beat rates were compared before and after transplacental terbutaline treatment (10 to 30 mg/day) by fetal echocardiography in 17 fetuses with CHB caused by immune-mediated damage to a normal conduction system (isoimmune, n = 8) or a congenitally malformed conduction system associated with left atrial isomerism (LAI, n = 9). While receiving terbutaline, 9 of the 17 fetuses underwent fetal magnetocardiography (fMCG) to assess maternal HR and rhythm, patterns of fetal HR acceleration, and correlation between fetal atrial and ventricular accelerations (i.e., AV correlation). Maternal HR and fetal atrial and ventricular beat rates increased with terbutaline. However, terbutaline's effects were greater on the atrial pacemaker(s) in fetuses with isoimmune CHB and greater on the ventricular pacemaker(s) in those with LAI-associated CHB. Patterns of fetal HR acceleration also differed between isoimmune and LAI CHB. Finally, despite increasing HR, terbutaline did not restore the normal coordinated response between atrial and ventricular accelerations in isoimmune or LAI CHB. In conclusion, the pathophysiologic heterogeneity of CHB is reflected in the differing effect of terbutaline on the atrial and ventricular pacemaker(s) and varying patterns of HR acceleration. However, regardless of the cause of CHB, terbutaline augments HR but not AV correlation, suggesting that its effects are determined by the conduction system defect rather than the autonomic control of the developing heart.

  1. Atrial and Ventricular Rate Response and Patterns of Heart Rate Acceleration during Maternal–Fetal Terbutaline Treatment of Fetal Complete Heart Block

    PubMed Central

    Cuneo, Bettina F.; Zhao, Hui; Strasburger, Janette F.; Ovadia, Marc; Huhta, James C.; Wakai, Ronald T.

    2012-01-01

    Terbutaline is used to treat fetal bradycardia in the setting of complete heart block (CHB); however, little is known of its effects on atrial and ventricular beat rates or patterns of heart rate (HR) acceleration. Fetal atrial and ventricular beat rates were compared before and after transplacental terbutaline treatment (10 to 30 mg/day) by fetal echocardiography in 17 fetuses with CHB caused by immune-mediated damage to a normal conduction system (isoimmune, n = 8) or a congenitally malformed conduction system associated with left atrial isomerism (LAI, n = 9). While receiving terbutaline, 9 of the 17 fetuses underwent fetal magnetocardiography (fMCG) to assess maternal HR and rhythm, patterns of fetal HR acceleration, and correlation between fetal atrial and ventricular accelerations (i.e., AV correlation). Maternal HR and fetal atrial and ventricular beat rates increased with terbutaline. However, terbutaline's effects were greater on the atrial pacemaker(s) in fetuses with isoimmune CHB and greater on the ventricular pacemaker(s) in those with LAI-associated CHB. Patterns of fetal HR acceleration also differed between isoimmune and LAI CHB. Finally, despite increasing HR, terbutaline did not restore the normal coordinated response between atrial and ventricular accelerations in isoimmune or LAI CHB. In conclusion, the pathophysiologic heterogeneity of CHB is reflected in the differing effect of terbutaline on the atrial and ventricular pacemaker(s) and varying patterns of HR acceleration. However, regardless of the cause of CHB, terbutaline augments HR but not AV correlation, suggesting that its effects are determined by the conduction system defect rather than the autonomic control of the developing heart. PMID:17697825

  2. Association between oral variables and heart rate variability

    PubMed Central

    2013-01-01

    The heart rate variability is a useful method to assess cardiac autonomic modulation in patients undergoing dental procedures, because knowledge of physiological conditions provides greater security to the professional as well as the possibility of a better plan treatment to patient benefit. The aim of our study was to describe the association between cardiac autonomic control and dental variables. We consulted the databases Medline, SciELO, Lilacs and Cochrane, using the terms “autonomic”, “dentistry”, “heart rate variability”, “cardiovascular physiology.” The selected studies indicated a strong relationship between dental variables and HRV. There was an association between malocclusion, TMD, dental procedures cirugia and low HRV. Thus, they become more studies that relate to HRV in dental science, especially in clinical practice. PMID:24373329

  3. gHRV: Heart rate variability analysis made easy.

    PubMed

    Rodríguez-Liñares, L; Lado, M J; Vila, X A; Méndez, A J; Cuesta, P

    2014-08-01

    In this paper, the gHRV software tool is presented. It is a simple, free and portable tool developed in python for analysing heart rate variability. It includes a graphical user interface and it can import files in multiple formats, analyse time intervals in the signal, test statistical significance and export the results. This paper also contains, as an example of use, a clinical analysis performed with the gHRV tool, namely to determine whether the heart rate variability indexes change across different stages of sleep. Results from tests completed by researchers who have tried gHRV are also explained: in general the application was positively valued and results reflect a high level of satisfaction. gHRV is in continuous development and new versions will include suggestions made by testers. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Association between oral variables and heart rate variability.

    PubMed

    Santana, Milana Drumond Ramos; de Souza, Ana Cecilia Amorim; de Abreu, Luiz Carlos; Valenti, Vitor E

    2013-12-27

    The heart rate variability is a useful method to assess cardiac autonomic modulation in patients undergoing dental procedures, because knowledge of physiological conditions provides greater security to the professional as well as the possibility of a better plan treatment to patient benefit. The aim of our study was to describe the association between cardiac autonomic control and dental variables. We consulted the databases Medline, SciELO, Lilacs and Cochrane, using the terms "autonomic", "dentistry", "heart rate variability", "cardiovascular physiology." The selected studies indicated a strong relationship between dental variables and HRV. There was an association between malocclusion, TMD, dental procedures cirugia and low HRV. Thus, they become more studies that relate to HRV in dental science, especially in clinical practice.

  5. Qigong Effects on Heart Rate Variability and Peripheral Vasomotor Responses.

    PubMed

    Chang, Mei-Ying

    2015-11-01

    Population aging is occurring worldwide, and preventing cardiovascular event in older people is a unique challenge. The aim of this study was to examine the effects of a 12-week qigong (eight-form moving meditation) training program on the heart rate variability and peripheral vasomotor response of middle-aged and elderly people in the community. This was a quasi-experimental study that included the pre-test, post-test, and nonequivalent control group designs. Seventy-seven participants (experimental group = 47; control group = 30) were recruited. The experimental group performed 30 min of eight-form moving meditation 3 times per week for 12 weeks, and the control group continued their normal daily activities. After 12 weeks, the interaction effects indicated that compared with the control group, the experimental group exhibited significantly improved heart rate variability and peripheral vasomotor responses.

  6. Evaluation of wearable consumer heart rate monitors based on photopletysmography.

    PubMed

    Parak, Jakub; Korhonen, Ilkka

    2014-01-01

    Wearable monitoring of heart rate (HR) during physical activity and exercising allows real time control of exercise intensity and training effect. Recently, technologies based on pulse plethysmography (PPG) have become available for personal health management for consumers. However, the accuracy of these monitors is poorly known which limits their application. In this study, we evaluated accuracy of two PPG based (wrist i.e. Mio Alpha vs forearm i.e. Schosche Rhythm) commercially available HR monitors during exercise. 21 healthy volunteers (15 male and 6 female) completed an exercise protocol which included sitting, lying, walking, running, cycling, and some daily activities involving hand movements. HR estimation was compared against values from the reference electrocardiogram (ECG) signal. The heart rate estimation reliability scores for <;5% accuracy against reference were following: mio Alpha 77,83% and Scosche Rhytm 76,29%. The estimated results indicate that performance of devices depends on various parameters, including specified activity, sensor type and device placement.

  7. Heart rate variability reactivity and new romance: Cause or consequence?

    PubMed

    Bailey, Laura K; Davis, Ron

    2017-09-01

    There are documented physiological differences between single and coupled individuals during the "honeymoon period" of nascent romantic relationships. One such difference is in autonomic reactivity, specifically heart rate variability (HRV) reactivity. This finding had previously been interpreted as evidence of a stress buffering effect of relationship formation. The present study explored among university women two competing longitudinal hypotheses conceptualizing differences in HRV reactivity as either a cause or a consequence of romantic relationship formation. Results did not support the hypothesis that HRV reactivity changes as a consequence of beginning a new romantic relationship. Instead, lower HRV reactivity predicted greater relationship formation amongst women with low BMI and higher resting HRV. The functioning of the heart therefore predicted the likelihood that an individual would find love. These interactions may be the result of differing success rates of various mating strategies for women with low and high BMI and HRV. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Spectral photoplethysmographic imaging sensor fusion for enhanced heart rate detection

    NASA Astrophysics Data System (ADS)

    Amelard, Robert; Clausi, David A.; Wong, Alexander

    2016-03-01

    Continuous heart rate monitoring can provide important context for quantitative clinical assessment in scenarios such as long-term health monitoring and disability prevention. Photoplethysmographic imaging (PPGI) systems are particularly useful for such monitoring scenarios as contact-based devices pose problems related to comfort and mobility. Each pixel can be regarded as a virtual PPG sensor, thus enabling simultaneous measurements of multiple skin sites. Existing PPGI systems analyze temporal PPGI sensor uctuations related to hemodynamic pulsations across a region of interest to extract the blood pulse signal. However, due to spatially varying optical properties of the skin, the blood pulse signal may not be consistent across all PPGI sensors, leading to inaccurate heart rate monitoring. To increase the hemodynamic signal-to-noise ratio (SNR), we propose a novel spectral PPGI sensor fusion method for enhanced estimation of the true blood pulse signal. Motivated by the observation that PPGI sensors with high hemodynamic SNR exhibit a spectral energy peak at the heart rate frequency, an entropy-based fusion model was formulated to combine PPGI sensors based on the sensors' spectral energy distribution. The optical PPGI device comprised a near infrared (NIR) sensitive camera and an 850 nm LED. Spatially uniform irradiance was achieved by placing optical elements along the LED beam, providing consistent illumination across the skin area. Dual-mode temporally coded illumination was used to negate the temporal effect of ambient illumination. Experimental results show that the spectrally weighted PPGI method can accurately and consistently extract heart rate information where traditional region-based averaging fails.

  9. Scaling and Ordering of Neonatal Heart Rate Variability

    NASA Astrophysics Data System (ADS)

    Aghili, Ali A.; Rizwan-Uddin, Rizwan-Uddin; Griffin, M. Pamela; Moorman, J. Randall

    1995-02-01

    By analyzing cardiac beat-to-beat intervals and interbeat increments, we find that-unlike adults-the difference in the pattern of interbeat increments in healthy and sick newborn infants is more due to a change in the amplitude and much less to a change in the ordering of the interbeat increments. This suggests that very low-frequency elements of neonatal and adult heart rate variability rise from fundamentally different mechanisms.

  10. Orthostatic heart rate responses after prolonged space flights.

    PubMed

    Tank, Jens; Baevsky, Roman M; Funtova, Irina I; Diedrich, André; Slepchenkova, Irina N; Jordan, Jens

    2011-04-01

    Orthostatic tachycardia (POTS) can occur after space flights. We determined orthostatic heart rate responses in 18 cosmonauts before and 3-5 days after long-term space missions. Cosmonauts undergoing a cardiovascular training program in space experienced only moderate POTS after their return to earth. Cardiovascular countermeasures may have attenuated POTS. Another possible interpretation is that cardiovascular deconditioning is not sufficient to elicit full blown POTS in the absence of additional genetic or environmental factors.

  11. Assessing Metabolic Syndrome Through Increased Heart Rate During Exercise.

    PubMed

    Sadeghi, Masoumeh; Gharipour, Mojgan; Nezafati, Pouya; Shafie, Davood; Aghababaei, Esmaeil; Sarrafzadegan, Nizal

    2016-11-01

    The present study aimed to assess changes in resting and maximum heart rates as primary indicators of cardiac autonomic function in metabolic syndrome (MetS) patients and to determine their value for discriminating MetS from non-MetS. 468 participants were enrolled in this cross-sectional study and assessed according to the updated adult treatment panel III (ATP-III) definition of MetS. Resting and maximum heart rates were recorded following the Bruce protocol during an exercise. A receiver operating characteristic (ROC) curve was used to identify the best cutoff point for discriminating MetS from the non-MetS state. 194 participants (41.5%) were diagnosed as MetS. The mean resting heart rate (RHR) was not statistically different between the two groups (P=0.078). However, the mean maximum heart (MHR) rate was considerably higher in participants with MetS (142.37±14.84 beats per min) compared to the non-MetS group (134.62±21.63 beats per min) (P<0.001). In the MetS group, the MHR was positively correlated with the serum triglyceride level (β=0.185, P=0.033) and was inversely associated with age (β=-0.469, P<0.001). The MHR had a moderate value for discriminating MetS from the non-MetS state (c=0.580, P=0.004) with the optimal cutoff point of 140 beats per min. In MetS patients, the MHR was significantly greater compared to non-MetS subjects and was directly correlated with serum triglyceride levels and inversely with advanced age. Moreover, MHR can be used as a suspicious indicator for identifying MetS.

  12. Prediction of Maximal Heart Rate in Children and Adolescents.

    PubMed

    Gelbart, Miri; Ziv-Baran, Tomer; Williams, Craig A; Yarom, Yoni; Dubnov-Raz, Gal

    2017-03-01

    To identify a method to predict the maximal heart rate (MHR) in children and adolescents, as available prediction equations developed for adults have a low accuracy in children. We hypothesized that MHR may be influenced by resting heart rate, anthropometric factors, or fitness level. Cross-sectional study. Sports medicine center in primary care. Data from 627 treadmill maximal exercise tests performed by 433 pediatric athletes (age 13.7 ± 2.1 years, 70% males) were analyzed. Age, sex, sport type, stature, body mass, BMI, body fat, fitness level, resting, and MHR were recorded. To develop a prediction equation for MHR in youth, using stepwise multivariate linear regression and linear mixed model. To determine correlations between existing prediction equations and pediatric MHR. Observed MHR was 197 ± 8.6 b·min. Regression analysis revealed that resting heart rate, fitness, body mass, and fat percent were predictors of MHR (R = 0.25, P < 0.001), whereas age was not. Resting heart rate explained 15.6% of MHR variance, body mass added 5.7%, fat percent added 2.4%, and fitness added 1.2%. Existing adult equations had low correlations with observed MHR in children and adolescents (r = -0.03-0.34). A new equation to predict MHR in children and adolescents was developed, but was found to have low predictive ability, a finding similar to adult equations applied to children. Considering the narrow range of MHR in youth, we propose using 197 b·min as the mean MHR in children and adolescents, with 180 b·min the minimal threshold value (-2 standard deviations).

  13. Heart rate variability related to effort at work.

    PubMed

    Uusitalo, Arja; Mets, Terhi; Martinmäki, Kaisu; Mauno, Saija; Kinnunen, Ulla; Rusko, Heikki

    2011-11-01

    Changes in autonomic nervous system function have been related to work stress induced increases in cardiovascular morbidity and mortality. Our purpose was to examine whether various heart rate variability (HRV) measures and new HRV-based relaxation measures are related to self-reported chronic work stress and daily emotions. The relaxation measures are based on neural network modelling of individual baseline heart rate and HRV information. Nineteen healthy hospital workers were studied during two work days during the same work period. Daytime, work time and night time heart rate, as well as physical activity were recorded. An effort-reward imbalance (ERI) questionnaire was used to assess chronic work stress. The emotions of stress, irritation and satisfaction were assessed six times during both days. Seventeen subjects had an ERI ratio over 1, indicating imbalance between effort and reward, that is, chronic work stress. Of the daily emotions, satisfaction was the predominant emotion. The daytime relaxation percentage was higher on Day 2 than on Day 1 (4 ± 6% vs. 2 ± 3%, p < 0.05) and the night time relaxation (43 ± 30%) was significantly higher than daytime or work time relaxation on the both Days. Chronic work stress correlated with the vagal activity index of HRV. However, effort at work had many HRV correlates: the higher the work effort the lower daytime HRV and relaxation time. Emotions at work were also correlated with work time (stress and satisfaction) and night time (irritation) HRV. These results indicate that daily emotions at work and chronic work stress, especially effort, is associated with cardiac autonomic function. Neural network modelling of individual heart rate and HRV information may provide additional information in stress research in field conditions.

  14. Cholesterol enhances classical conditioning of the rabbit heart rate response.

    PubMed

    Schreurs, Bernard G; Smith-Bell, Carrie A; Darwish, Deya S; Wang, Desheng; Burhans, Lauren B; Gonzales-Joekes, Jimena; Deci, Stephen; Stankovic, Goran; Sparks, D Larry

    2007-07-19

    The cholesterol-fed rabbit is a model of atherosclerosis and has been proposed as an animal model of Alzheimer's disease. Feeding rabbits cholesterol has been shown to increase the number of beta amyloid immunoreactive neurons in the cortex. Addition of copper to the drinking water of cholesterol-fed rabbits can increase this number still further and may lead to plaque-like structures. Classical conditioning of the nictitating membrane response in cholesterol-fed rabbits is retarded in the presence of these plaque-like structures but may be facilitated in their absence. In a factorial design, rabbits fed 2% cholesterol or a normal diet (0% cholesterol) for 8 weeks with or without copper added to the drinking water were given trace classical conditioning using a tone and periorbital electrodermal stimulation to study the effects of cholesterol and copper on classical conditioning of heart rate and the nictitating membrane response. Cholesterol-fed rabbits showed significant facilitation of heart rate conditioning and conditioning-specific modification of heart rate relative to normal diet controls. Consistent with previous research, cholesterol had minimal effects on classical conditioning of the nictitating membrane response when periorbital electrodermal stimulation was used as the unconditioned stimulus. Immunohistochemical analysis showed a significant increase in the number of beta amyloid positive neurons in the cortex, hippocampus and amygdala of the cholesterol-fed rabbits. Supplementation of drinking water with copper increased the number of beta amyloid positive neurons in the cortex of cholesterol-fed rabbits but did not produce plaque-like structures or have a significant effect on heart rate conditioning. The data provide additional support for our finding that, in the absence of plaques, dietary cholesterol may facilitate learning and memory.

  15. Cholesterol enhances classical conditioning of the rabbit heart rate response

    PubMed Central

    Schreurs, Bernard G.; Smith-Bell, Carrie A.; Darwish, Deya S.; Wang, Desheng; Burhans, Lauren B.; Gonzales-Joekes, Jimena; Deci, Stephen; Stankovic, Goran; Sparks, D. Larry

    2007-01-01

    The cholesterol-fed rabbit is a model of atherosclerosis and has been proposed as an animal model of Alzheimer's disease. Feeding rabbits cholesterol has been shown to increase the number of beta amyloid immunoreactive neurons in the cortex. Addition of copper to the drinking water of cholesterol-fed rabbits can increase this number still further and may lead to plaque-like structures. Classical conditioning of the nictitating membrane response in cholesterol-fed rabbits is retarded in the presence of these plaque-like structures but may be facilitated in their absence. In a factorial design, rabbits fed 2% cholesterol or a normal diet (0% cholesterol) for 8 weeks with or without copper added to the drinking water were given trace classical conditioning using a tone and periorbital electrodermal stimulation to study the effects of cholesterol and copper on classical conditioning of heart rate and the nictitating membrane response. Cholesterol-fed rabbits showed significant facilitation of heart rate conditioning and conditioning-specific modification of heart rate relative to normal diet controls. Consistent with previous research, cholesterol had minimal effects on classical conditioning of the nictitating membrane response when periorbital electrodermal stimulation was used as the unconditioned stimulus. Immunohistochemical analysis showed a significant increase in the number of beta amyloid positive neurons in the cortex, hippocampus and amygdala of the cholesterol-fed rabbits. Supplementation of drinking water with copper increased the number of beta amyloid positive neurons in the cortex of cholesterol-fed rabbits but did not produce plaque-like structures or have a significant effect on heart rate conditioning. The data provide additional support for our finding that, in the absence of plaques, dietary cholesterol may facilitate learning and memory. PMID:17466388

  16. Obstructive sleep apnea and heart rate asymmetry microstructure during sleep.

    PubMed

    Guzik, Przemyslaw; Piskorski, Jaroslaw; Awan, Kokab; Krauze, Tomasz; Fitzpatrick, Michael; Baranchuk, Adrian

    2013-04-01

    Heart rate decelerations and accelerations have unequal input to heart rate variability (HRV) and patterns created by consecutive cardiac cycles-this phenomenon is known as heart rate asymmetry (HRA). The analysis of monotonic runs of heart rate decelerations and accelerations provides a detailed insight into the HRA microstructure and thus of HRV. To evaluate the relation between the severity of obstructive sleep apnea (OSA) and the HRA microstructure during sleep. Seventy-eight patients with suspected OSA underwent overnight polysomnography. The 300-min ECGs from the polysomnography were selected and analyzed. The HRA microstructure was quantified by measuring (1) the contribution of monotonic runs of decelerations or accelerations of different lengths to the number of all sinus beats, and (2) the length of the longest deceleration and acceleration runs. There were 19 patients with no/mild OSA (Apnea/Hypopnea Index (AHI) 5.1 ± 2.5/h), 18 with moderate OSA (AHI 21.8 ± 4.0/h) and 41 with severe OSA (AHI 42.8 ± 17.4/h). Patients with severe OSA had significantly reduced deceleration and acceleration runs of length 1 compared to the moderate OSA group, and compared to patients with no/mild OSA they had an increased number of longer runs (from 5 to 10 for accelerations and from 5 to 8 for decelerations; p < 0.05 for all comparisons). The longest acceleration runs were significantly longer in severe OSA group (p < 0.05) than in subjects with no/mild OSA. HRA microstructure is related with OSA severity. An increased number of longer deceleration and acceleration runs is more common in severe OSA patients.

  17. Heritability of heart rate recovery and vagal rebound after exercise.

    PubMed

    Nederend, Ineke; Schutte, Nienke M; Bartels, Meike; Ten Harkel, Arend D J; de Geus, Eco J C

    2016-12-01

    The prognostic power of heart rate recovery (HRR) after exercise has been well established but the exact origin of individual differences in HRR remains unclear. This study aims to estimate the heritability of HRR and vagal rebound after maximal exercise in adolescents. Furthermore, the role of voluntary regular exercise behavior (EB) in HRR and vagal rebound is tested. 491 healthy adolescent twins and their siblings were recruited for maximal exercise testing, followed by a standardized cooldown with measurement of the electrocardiogram and respiratory frequency. Immediate and long-term HRR (HRR60 and HRR180) and vagal rebound (heart rate variability in the respiratory frequency range) were assessed 1 and 3 min after exercise. Multivariate twin modeling was used to estimate heritability of all measured variables and to compute the genetic contribution to their covariance. Heritability of HRR60, HRR180 and immediate and long-term vagal rebound is 60 % (95 % CI: 48-67), 65 % (95 % CI: 54-73), 23 % (95 % CI: 11-35) and 3 % (95 % CI: 0-11), respectively. We find evidence for two separate genetic factors with one factor influencing overall cardiac vagal control, including resting heart rate and respiratory sinus arrhythmia, and a specific factor for cardiac vagal exercise recovery. EB was only modestly associated with resting heart rate (r = -0.27) and HRR (rHRR60 = 0.10; rHRR180 = 0.19) with very high genetic contribution to these associations (88-91 %). Individual differences in HRR and immediate vagal rebound can to a large extent be explained by genetic factors. These innate cardiac vagal exercise recovery factors partly reflect the effects of heritable differences in EB.

  18. Blood pressure and heart rate adjustment following acute Frenkel's ambulatory exercise in chronic hemiparetics stroke survivors: a comparative study.

    PubMed

    Isa, Lawal; Abubakar, Aliyu; Rufa'i, Ahmad; Mukadas, Akindele

    2014-12-01

    Frenkel's ambulatory activity has been routinely employed by physiotherapists for rehabilitation of gait coordination, however, its immediate influence on blood pressure and heart rate has not been investigated. To investigate the acute effect of Frenkel's ambulatory activity on blood pressure and heart rate of chronic hemiparetic stroke survivors. Using a comparative study design, 60 chronic hemiparetic stroke survivors of varying onset of stroke, ≤6, >6-11 and ≥12 months were subjected to a 2-minute Frenkel's ambulatory activity on marked footsteps (from standard adult described footsteps). Participants were assessed for both blood pressure and heart rate before and after the Frenkel's ambulatory activity. Blood pressure and heart rate significantly increased (p<0.05) following Frenkel's ambulatory activity in all the 3 categories of stroke onset above baseline. However, there was no significant difference (p>0.05) across the onsets in both blood pressure and heart rate responses. The outcome of this study indicated that Frenkel's ambulatory activity has the propensity to increase blood pressure and heart rate of hemiparetic stroke survivors irrespective of the onset of stroke. We recommend a pre, within and post-activity monitoring of stroke survivors while subjecting them to Frenkel's ambulatory activity.

  19. Post-Exercise Heart Rate Recovery Independently Predicts Mortality Risk in Patients with Chronic Heart Failure

    PubMed Central

    Tang, Yi-Da; Dewland, Thomas A.; Wencker, Detlef; Katz, Stuart D.

    2009-01-01

    Background Post-exercise heart rate recovery (HRR) is an index of parasympathetic function associated with clinical outcomes in populations with and without documented coronary heart disease. Decreased parasympathetic activity is thought to be associated with disease progression in chronic heart failure (HF), but an independent association between post-exercise HRR and clinical outcomes among such patients has not been established. Methods and Results We measured HRR (calculated as the difference between heart rate at peak exercise and after 1 minute of recovery) in 202 HF subjects and recorded 17 mortality and 15 urgent transplantation outcome events over 624 days of follow-up. Reduced post-exercise HRR was independently associated with increased event risk after adjusting for other exercise-derived variables (peak oxygen uptake and VE/VCO2 slope), for the Heart Failure Survival Score (adjusted HR 1.09 for one beat/min reduction, 95% CI 1.05-1.13, p<0.0001) and the Seattle Heart Failure Model score (adjusted HR 1.08 for one beat/min reduction, 95% CI 1.05-1.12, p<0.0001). Subjects in the lowest risk tertile based on post-exercise HRR (≥30 beats/min) had low risk of events irrespective of the risk predicted by the survival scores. In a subgroup of 15 subjects, reduced post-exercise HRR was associated with increased serum markers of inflammation (interleukin-6 r=0.58, p=0.024, high sensitivity C-reactive protein r=0.66, p=0.007). Conclusions Post-exercise HRR predicts mortality risk in patients with HF and provides prognostic information independent of previously described survival models. Pathophysiologic links between autonomic function and inflammation may be mediators of this association. PMID:19944361

  20. Post-exercise heart rate recovery independently predicts mortality risk in patients with chronic heart failure.

    PubMed

    Tang, Yi-Da; Dewland, Thomas A; Wencker, Detlef; Katz, Stuart D

    2009-12-01

    Post-exercise heart rate recovery (HRR) is an index of parasympathetic function associated with clinical outcomes in populations with and without documented coronary heart disease. Decreased parasympathetic activity is thought to be associated with disease progression in chronic heart failure (HF), but an independent association between post-exercise HRR and clinical outcomes among such patients has not been established. We measured HRR (calculated as the difference between heart rate at peak exercise and after 1 minute of recovery) in 202 HF subjects and recorded 17 mortality and 15 urgent transplantation outcome events over 624 days of follow-up. Reduced post-exercise HRR was independently associated with increased event risk after adjusting for other exercise-derived variables (peak oxygen uptake and change in minute ventilation per change in carbon dioxide production slope), for the Heart Failure Survival Score (adjusted HR 1.09 for 1 beat/min reduction, 95% CI 1.05-1.13, P < .0001), and the Seattle Heart Failure Model score (adjusted HR 1.08 for one beat/min reduction, 95% CI 1.05-1.12, P < .0001). Subjects in the lowest risk tertile based on post-exercise HRR (>or=30 beats/min) had low risk of events irrespective of the risk predicted by the survival scores. In a subgroup of 15 subjects, reduced post-exercise HRR was associated with increased serum markers of inflammation (interleukin-6, r = 0.58, P = .024; high-sensitivity C-reactive protein, r = 0.66, P = .007). Post-exercise HRR predicts mortality risk in patients with HF and provides prognostic information independent of previously described survival models. Pathophysiologic links between autonomic function and inflammation may be mediators of this association.

  1. Effect of lung transplantation on heart rate response to exercise.

    PubMed

    Armstrong, Hilary F; Gonzalez-Costello, Jose; Thirapatarapong, Wilawan; Jorde, Ulrich P; Bartels, Matthew N

    2015-01-01

    To evaluate if patients have a change in percent of predicted heart rate reserve used at peak exercise (%HRR) after lung transplantation, even at matching workloads. Lung disease of obstructive, restrictive, and mixed types may be associated with an autonomic imbalance. Lung transplantation may improve the effects of pulmonary disease on cardiac function. However, the effect of lung transplantation on heart rate responses during exercise has not been investigated in detail. Retrospective review of patients who underwent lung transplantation. Pre and post transplant cardiopulmonary exercise tests were reviewed. The %HRR significantly improved by a median of 37% (p < 0.001) following lung transplantation. When matching workloads were analyzed, the %HRR also decreased from a median of 36% to 24% (p < 0.001). Corresponding to an increase in peak exercise capacity, percentage of heart rate reserve used improves significantly after lung transplantation, even at matching workloads, indicating a likely improvement in autonomic modulation. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Practical remarks on the heart rate and saturation measurement methodology

    NASA Astrophysics Data System (ADS)

    Kowal, M.; Kubal, S.; Piotrowski, P.; Staniec, K.

    2017-05-01

    A surface reflection-based method for measuring heart rate and saturation has been introduced as one having a significant advantage over legacy methods in that it lends itself for use in special applications such as those where a person’s mobility is of prime importance (e.g. during a miner’s work) and excluding the use of traditional clips. Then, a complete ATmega1281-based microcontroller platform has been described for performing computational tasks of signal processing and wireless transmission. In the next section remarks have been provided regarding the basic signal processing rules beginning with raw voltage samples of converted optical signals, their acquisition, storage and smoothing. This chapter ends with practical remarks demonstrating an exponential dependence between the minimum measurable heart rate and the readout resolution at different sampling frequencies for different cases of averaging depth (in bits). The following section is devoted strictly to the heart rate and hemoglobin oxygenation (saturation) measurement with the use of the presented platform, referenced to measurements obtained with a stationary certified pulsoxymeter.

  3. Modeling heart rate variability including the effect of sleep stages

    NASA Astrophysics Data System (ADS)

    Soliński, Mateusz; Gierałtowski, Jan; Żebrowski, Jan

    2016-02-01

    We propose a model for heart rate variability (HRV) of a healthy individual during sleep with the assumption that the heart rate variability is predominantly a random process. Autonomic nervous system activity has different properties during different sleep stages, and this affects many physiological systems including the cardiovascular system. Different properties of HRV can be observed during each particular sleep stage. We believe that taking into account the sleep architecture is crucial for modeling the human nighttime HRV. The stochastic model of HRV introduced by Kantelhardt et al. was used as the initial starting point. We studied the statistical properties of sleep in healthy adults, analyzing 30 polysomnographic recordings, which provided realistic information about sleep architecture. Next, we generated synthetic hypnograms and included them in the modeling of nighttime RR interval series. The results of standard HRV linear analysis and of nonlinear analysis (Shannon entropy, Poincaré plots, and multiscale multifractal analysis) show that—in comparison with real data—the HRV signals obtained from our model have very similar properties, in particular including the multifractal characteristics at different time scales. The model described in this paper is discussed in the context of normal sleep. However, its construction is such that it should allow to model heart rate variability in sleep disorders. This possibility is briefly discussed.

  4. Emotions, heart rate and performance in archery. A case study.

    PubMed

    Robazza, C; Bortoli, L; Nougier, V

    1999-06-01

    A case study of an elite female archer was conducted to gain insight into individual psychophysical reactions accompanying an athletic event, and to test predictions of pre-performance emotions effects upon performance. Good performance was expected when the actual pre-performance emotions resembled the recalled optimal emotion pattern. Conversely, poor performance was expected when the actual pre-performance emotions paralleled the recalled ineffective emotion pattern. the investigation comprised individual emotion profiling, emotions and heart rate monitoring, final interview and performance evaluation. The research was accomplished during the 1996 European Archery Championships, one of the most important international archery competitions. An 18-year-old female athlete of the Italian archery national team. Because of the exploratory nature of the study, no intervention was implemented. Emotion profiling was carried out using an idiographic approach based on recalled optimal and poor performances, according to the Individual Zones of Optimal Functioning (IZOF) model. Emotions, heart rate, and performance were monitored across the five days of practice and competition. Individual pre-performance optimal emotion pattern, heart rate deceleration during shooting, consistent shooting scores were revealed throughout practice and competition. The good performance predicted on the basis of pre-performance emotion assessments was met and was confirmed by the archer's interpretation.

  5. Stress Detection Using Low Cost Heart Rate Sensors.

    PubMed

    Salai, Mario; Vassányi, István; Kósa, István

    2016-01-01

    The automated detection of stress is a central problem for ambient assisted living solutions. The paper presents the concepts and results of two studies targeted at stress detection with a low cost heart rate sensor, a chest belt. In the device validation study ( n = 5), we compared heart rate data and other features from the belt to those measured by a gold standard device to assess the reliability of the sensor. With simple synchronization and data cleaning algorithm, we were able to select highly (>97%) correlated, low average error (2.2%) data segments of considerable length from the chest data for further processing. The protocol for the clinical study ( n = 46) included a relax phase followed by a phase with provoked mental stress, 10 minutes each. We developed a simple method for the detection of the stress using only three time-domain features of the heart rate signal. The method produced accuracy of 74.6%, sensitivity of 75.0%, and specificity of 74.2%, which is impressive compared to the performance of two state-of-the-art methods run on the same data. Since the proposed method uses only time-domain features, it can be efficiently implemented on mobile devices.

  6. Modeling heart rate variability including the effect of sleep stages.

    PubMed

    Soliński, Mateusz; Gierałtowski, Jan; Żebrowski, Jan

    2016-02-01

    We propose a model for heart rate variability (HRV) of a healthy individual during sleep with the assumption that the heart rate variability is predominantly a random process. Autonomic nervous system activity has different properties during different sleep stages, and this affects many physiological systems including the cardiovascular system. Different properties of HRV can be observed during each particular sleep stage. We believe that taking into account the sleep architecture is crucial for modeling the human nighttime HRV. The stochastic model of HRV introduced by Kantelhardt et al. was used as the initial starting point. We studied the statistical properties of sleep in healthy adults, analyzing 30 polysomnographic recordings, which provided realistic information about sleep architecture. Next, we generated synthetic hypnograms and included them in the modeling of nighttime RR interval series. The results of standard HRV linear analysis and of nonlinear analysis (Shannon entropy, Poincaré plots, and multiscale multifractal analysis) show that-in comparison with real data-the HRV signals obtained from our model have very similar properties, in particular including the multifractal characteristics at different time scales. The model described in this paper is discussed in the context of normal sleep. However, its construction is such that it should allow to model heart rate variability in sleep disorders. This possibility is briefly discussed.

  7. Factors related to heart rate variability among firefighters.

    PubMed

    Shin, Jae-Hong; Lee, Jung-Youb; Yang, Seon-Hee; Lee, Mi-Young; Chung, In-Sung

    2016-01-01

    The aim of this study was to investigate factors associated with heart rate variability in firefighters working in a metropolitan city in South Korea. Self-administered questionnaires including Korean Occupational Stress Scale (KOSS) as well as surveys collecting socio-demographic characteristics and work-related factors were given to 962 firefighters. After exclusion for missing data, 645 firefighters were included, and analysis of covaiance adjusted for the general risk factors and job characteristics were used to assess the relationship between heart rate variability and associated factors. SDNN and RMSSD and were decreased in the area of occupational climate of the group with high job stress (p = 0.027, p = 0.036). HF(ln) was decreased in the area of organizational system and occupational climate of the group with high stress that statistically significant level (p = 0.034, p = 0.043). Occupational climate and organizational system are associated with reduction of heart rate variability. Preventive medical care plans for cardiovascular disease of firefighters through the analysis and evaluation of job stress factors are needed.

  8. Stress Detection Using Low Cost Heart Rate Sensors

    PubMed Central

    Salai, Mario; Kósa, István

    2016-01-01

    The automated detection of stress is a central problem for ambient assisted living solutions. The paper presents the concepts and results of two studies targeted at stress detection with a low cost heart rate sensor, a chest belt. In the device validation study (n = 5), we compared heart rate data and other features from the belt to those measured by a gold standard device to assess the reliability of the sensor. With simple synchronization and data cleaning algorithm, we were able to select highly (>97%) correlated, low average error (2.2%) data segments of considerable length from the chest data for further processing. The protocol for the clinical study (n = 46) included a relax phase followed by a phase with provoked mental stress, 10 minutes each. We developed a simple method for the detection of the stress using only three time-domain features of the heart rate signal. The method produced accuracy of 74.6%, sensitivity of 75.0%, and specificity of 74.2%, which is impressive compared to the performance of two state-of-the-art methods run on the same data. Since the proposed method uses only time-domain features, it can be efficiently implemented on mobile devices. PMID:27372071

  9. Experimental heart rate regulation in cycle-ergometer exercises.

    PubMed

    Paradiso, Michele; Pietrosanti, Stefano; Scalzi, Stefano; Tomei, Patrizio; Verrelli, Cristiano Maria

    2013-01-01

    The heart rate can be effectively used as a measure of the exercise intensity during long duration cycle-ergometer exercises: precisely controlling the heart rate (HR) becomes crucial especially for athletes or patients with cardiovascular/obesity problems. The aim of this letter is to experimentally show how the nonlocal and nonswitching nonlinear control that has been recently proposed in the literature for the HR regulation in treadmill exercises can be effectively applied to cycle-ergometer exercises at constant cycling speed. The structure of the involved nonlinear model for the HR dynamics in cycle-ergometer exercises is mathematically inspired by the structure of a recently identified and experimentally validated nonlinear model for the HR dynamics in treadmill exercises: the role played by the treadmill speed is played here by the work load while the zero speed case for the treadmill exercise is here translated into the cycling operation under zero work load. Experimental results not only validate the aforementioned nonlinear model but also demonstrate the effectiveness--in terms of precise HR regulation--of an approach which simply generalizes to the nonlinear framework the classical proportional-integral control design. The possibility of online modifying the HR reference on the basis of the heart rate variability (HRV) is also suggested and experimentally motivated.

  10. Effects of Stretching Exercise on Heart Rate Variability During Pregnancy.

    PubMed

    Logan, Jeongok G; Yeo, SeonAe

    Little evidence exists for effects of low-intensity exercises such as stretching on cardiovascular health in pregnant women. Our aim was to evaluate the effect of a 20-minute stretching exercise on heart rate variability (HRV), blood pressure (BP), and heart rate (HR) in healthy pregnant women. In 15 pregnant women with a mean (SD) age of 29.47 (4.07) years and mean (SD) gestational weeks of 26.53 (8.35), HRV, and BP were measured before and after the 20-minute stretching exercise. Compared with before the stretching exercise, standard deviation of the normal-to-normal intervals, total variability of heart rate, increased by 7.40 milliseconds (t = -2.31, P = .04) and root mean square of successive differences, a surrogate measure of parasympathetic outflow, also increased by 11.68 milliseconds (Z = -2.04, P = .04) after the stretching exercise. Diastolic BP and HR decreased by 2.13 mm Hg (t = 1.93, P = .07) and 3.31 bpm (t = 2.17, P = .05), respectively, but they did not reach statistical significance. These preliminary data suggest that 20 minutes of stretching exercise may promote cardiovascular health by attenuating the loss of parasympathetic tone associated with pregnancy.

  11. Impaired post exercise heart rate recovery in anabolic steroid users.

    PubMed

    dos Santos, M R; Dias, R G; Laterza, M C; Rondon, M U P B; Braga, A M F W; de Moraes Moreau, R L; Negrão, C E; Alves, M-J N N

    2013-10-01

    Previous study showed that muscle sympathetic nerve activity (MSNA) was augmented in anabolic steroids users (AASU). In the present study, we tested the hypothesis that the heart rate (HR) responses after maximal exercise testing would be reduced in AASU. 10 male AASU and 10 AAS nonusers (AASNU) were studied. Cardiopulmonary exercise was performed to assess the functional capacity and heart rate recovery. MSNA was recorded directly from the peroneal nerve by microneurography technique. Peak oxygen consumption (VO₂) was lower in AASU compared to AASNU (43.66±2.24 vs. 52.70±1.68 ml/kg/min, P=0.005). HR recovery (HRR) at first and second minute was lower in AASU than AASNU (21±2 vs. 27±2 bpm, P=0.02 and 37±4 vs. 45±2 bpm, P=0.05, respectively). MSNA was higher in AASU than AASNU (29±3 vs. 20±1 bursts/min, P=0.01). Further analysis showed a correlation between HRR and MSNA (r=- 0.64, P=0.02), HRR at first minute and peak VO₂ (r=0.70, P=0.01) and HRR at second minute and peak VO₂ (r=0.62, P=0.02). The exacerbated sympathetic outflow associated with a lower parasympathetic activation after maximal exercise, which impairs heart rate recovery, strengthens the idea of autonomic imbalance in AASU. © Georg Thieme Verlag KG Stuttgart · New York.

  12. Design and development of a heart rate variability analyzer.

    PubMed

    Mohan, Aparna; James, Frana; Fazil, Sajeer; Joseph, Paul K

    2012-06-01

    Heart rate variability (HRV), analysis gives an insight into the state of the autonomic nervous system which modulates the cardiac activity. Here a digital signal controller based handy device is developed which acquires the beat to beat time interval, processes it using techniques based on non-linear dynamics, fractal time series analysis, and information theory. The technique employed, that can give reliable results by assessing heart beat signals fetched for a duration of a few minutes, is a huge advantage over the already existing methodologies of assessing cardiac health, those being dependant on the tedious task of acquiring Electro Cardio Gram(ECG) signals, which in turn requires the subject to lie down at a stretch for a couple of hours. The sensor used, relies on the technique of Photoplethysmography, rendering the whole approach as noninvasive. The device designed, calculates parameters like, Largest Lyapunov Exponent, Fractal dimension, Correlation Dimension, Approximate Entropy and α-slope of Poincare plots, which based on the range in which they fall, the cardiac health condition of the subject can be assessed to even the extend of predicting upcoming disorders. The design of heart beat sensor, the technique used in the acquisition of heart beat data, the relevant algorithm developed for the analysis purpose, are presented here.

  13. Classifying work rate from heart rate measurements using an adaptive neuro-fuzzy inference system.

    PubMed

    Kolus, Ahmet; Imbeau, Daniel; Dubé, Philippe-Antoine; Dubeau, Denise

    2016-05-01

    In a new approach based on adaptive neuro-fuzzy inference systems (ANFIS), field heart rate (HR) measurements were used to classify work rate into four categories: very light, light, moderate, and heavy. Inter-participant variability (physiological and physical differences) was considered. Twenty-eight participants performed Meyer and Flenghi's step-test and a maximal treadmill test, during which heart rate and oxygen consumption (VO2) were measured. Results indicated that heart rate monitoring (HR, HRmax, and HRrest) and body weight are significant variables for classifying work rate. The ANFIS classifier showed superior sensitivity, specificity, and accuracy compared to current practice using established work rate categories based on percent heart rate reserve (%HRR). The ANFIS classifier showed an overall 29.6% difference in classification accuracy and a good balance between sensitivity (90.7%) and specificity (95.2%) on average. With its ease of implementation and variable measurement, the ANFIS classifier shows potential for widespread use by practitioners for work rate assessment.

  14. Introducing a novel mechanism to control heart rate in the ancestral Pacific hagfish.

    PubMed

    Wilson, Christopher M; Roa, Jinae N; Cox, Georgina K; Tresguerres, Martin; Farrell, Anthony P

    2016-10-15

    Although neural modulation of heart rate is well established among chordate animals, the Pacific hagfish (Eptatretus stoutii) lacks any cardiac innervation, yet it can increase its heart rate from the steady, depressed heart rate seen in prolonged anoxia to almost double its normal normoxic heart rate, an almost fourfold overall change during the 1-h recovery from anoxia. The present study sought mechanistic explanations for these regulatory changes in heart rate. We provide evidence for a bicarbonate-activated, soluble adenylyl cyclase (sAC)-dependent mechanism to control heart rate, a mechanism never previously implicated in chordate cardiac control. © 2016. Published by The Company of Biologists Ltd.

  15. Pleiotropic, heart rate-independent cardioprotection by ivabradine

    PubMed Central

    Kleinbongard, P; Gedik, N; Witting, P; Freedman, B; Klöcker, N; Heusch, G

    2015-01-01

    Background and Purpose In pigs, ivabradine reduces infarct size even when given only at reperfusion and in the absence of heart rate reduction. The mechanism of this non-heart rate-related cardioprotection is unknown. Hence, in the present study we assessed the pleiotropic action of ivabradine in more detail. Experimental Approach Anaesthetized mice were pretreated with ivabradine (1.7 mg·kg−1 i.v.) or placebo (control) before a cycle of coronary occlusion/reperfusion (30/120 min ± left atrial pacing). Infarct size was determined. Isolated ventricular cardiomyocytes were exposed to simulated ischaemia/reperfusion (60/5 min) in the absence and presence of ivabradine, viability was then quantified and intra- and extracellular reactive oxygen species (ROS) formation was detected. Mitochondria were isolated from mouse hearts and exposed to simulated ischaemia/reperfusion (6/3 min) in glutamate/malate- and ADP-containing buffer in the absence and presence of ivabradine respectively. Mitochondrial respiration, extramitochondrial ROS, mitochondrial ATP production and calcium retention capacity (CRC) were assessed. Key Results Ivabradine decreased infarct size even with atrial pacing. Cardiomyocyte viability after simulated ischaemia/reperfusion was better preserved with ivabradin, the accumulation of intra- and extracellular ROS decreased in parallel. Mitochondrial complex I respiration was not different without/with ivabradine, but ivabradine significantly inhibited the accumulation of extramitochondrial ROS, increased mitochondrial ATP production and increased CRC. Conclusion and Implications Ivabradine reduces infarct size independently of a reduction in heart rate and improves ventricular cardiomyocyte viability, possibly by reducing mitochondrial ROS formation, increasing ATP production and CRC. PMID:26076181

  16. Pleiotropic, heart rate-independent cardioprotection by ivabradine.

    PubMed

    Kleinbongard, P; Gedik, N; Witting, P; Freedman, B; Klöcker, N; Heusch, G

    2015-09-01

    In pigs, ivabradine reduces infarct size even when given only at reperfusion and in the absence of heart rate reduction. The mechanism of this non-heart rate-related cardioprotection is unknown. Hence, in the present study we assessed the pleiotropic action of ivabradine in more detail. Anaesthetized mice were pretreated with ivabradine (1.7 mg · kg(-1) i.v.) or placebo (control) before a cycle of coronary occlusion/reperfusion (30/120 min ± left atrial pacing). Infarct size was determined. Isolated ventricular cardiomyocytes were exposed to simulated ischaemia/reperfusion (60/5 min) in the absence and presence of ivabradine, viability was then quantified and intra- and extracellular reactive oxygen species (ROS) formation was detected. Mitochondria were isolated from mouse hearts and exposed to simulated ischaemia/reperfusion (6/3 min) in glutamate/malate- and ADP-containing buffer in the absence and presence of ivabradine respectively. Mitochondrial respiration, extramitochondrial ROS, mitochondrial ATP production and calcium retention capacity (CRC) were assessed. Ivabradine decreased infarct size even with atrial pacing. Cardiomyocyte viability after simulated ischaemia/reperfusion was better preserved with ivabradine, the accumulation of intra- and extracellular ROS decreased in parallel. Mitochondrial complex I respiration was not different without/with ivabradine, but ivabradine significantly inhibited the accumulation of extramitochondrial ROS, increased mitochondrial ATP production and increased CRC. Ivabradine reduces infarct size independently of a reduction in heart rate and improves ventricular cardiomyocyte viability, possibly by reducing mitochondrial ROS formation, increasing ATP production and CRC. © 2015 The British Pharmacological Society.

  17. Abnormal heart rate variability and atrial fibrillation after aortic surgery

    PubMed Central

    Compostella, Leonida; Russo, Nicola; D’Onofrio, Augusto; Setzu, Tiziana; Compostella, Caterina; Bottio, Tomaso; Gerosa, Gino; Bellotto, Fabio

    2015-01-01

    Introduction Complete denervation of transplanted heart exerts protective effect against postoperative atrial fibrillation; various degrees of autonomic denervation appear also after transection of ascending aorta during surgery for aortic aneurysm. Objective This study aimed to evaluate if the level of cardiac denervation obtained by resection of ascending aorta could exert any effect on postoperative atrial fibrillation incidence. Methods We retrospectively analysed the clinical records of 67 patients submitted to graft replacement of ascending aorta (group A) and 132 with aortic valve replacement (group B); all episodes of postoperative atrial fibrillation occurred during the 1-month follow-up have been reported. Heart Rate Variability parameters were obtained from a 24-h Holter recording; clinical, echocardiographic and treatment data were also evaluated. Results Overall, 45% of patients (group A 43%, group B 46%) presented at least one episode of postoperative atrial fibrillation. Older age (but not gender, abnormal glucose tolerance, ejection fraction, left atrial diameter) was correlated with incidence of postoperative atrial fibrillation. Only among a subgroup of patients with aortic transection and signs of greater autonomic derangement (heart rate variability parameters below the median and mean heart rate over the 75th percentile), possibly indicating more profound autonomic denervation, a lower incidence of postoperative atrial fibrillation was observed (22% vs. 54%). Conclusion Transection of ascending aorta for repair of an aortic aneurysm did not confer any significant protective effect from postoperative atrial fibrillation in comparison to patients with intact ascending aorta. It could be speculated that a limited and heterogeneous cardiac denervation was produced by the intervention, creating an eletrophysiological substrate for the high incidence of postoperative atrial fibrillation observed. PMID:25859868

  18. Resting autonomic modulations and the heart rate response to exercise.

    PubMed

    Nunan, David; Jakovljevic, Djordje G; Donovan, Gay; Singleton, Lynette D; Sandercock, Gavin R H; Brodie, David A

    2010-08-01

    Identify the underlying role of resting heart rate variability (HRV) in the hearts response to graded exercise testing (GXT). Resting 5-min HRV and heart rate (HR) measurements were made in 33 volunteers (19 males, median age 34, range 25-63 years and 14 females median age 48, range 21-63 years). Measures of VO2 peak and HR obtained during a maximal GXT and heart rate recovery (HRR) post-GXT were assessed for associations with resting HRV. Differences and effect size (d) for measures of HRV were assessed between groups based on established risk cut-points for resting, exercise and recovery HR responses. Small associations were observed for the majority of resting HRV and GXT HR responses (best r value = -0.27, P > 0.05). Measures of HRV demonstrated moderate associations with HRR (best r value = 0.46, P < 0.05) and were able to predict a negative risk HRR. In contrast to other dependent variables, measures of HRV were consistently able to demonstrate significant and moderate to large (d = 0.9-2.0) differences between groups based on literature defined prognostic HR cut-points. Small associations with HR responses to exercise prevent their accurate prediction from resting HRV. Data support the use of vagally mediated resting HRV in predicting better HRR. Lower resting autonomic modulations underlined high risk resting and exercise HR responses. Resting short-term HRV measurements should be considered when assessing cardiac autonomic health from the HR response before, during and/or after exercise.

  19. Mesenchymal Stem Cells Improve Heart Rate Variability and Baroreflex Sensitivity in Rats with Chronic Heart Failure

    PubMed Central

    de Morais, Sharon Del Bem Velloso; da Silva, Luiz Eduardo Virgilio; Lataro, Renata Maria; Silva, Carlos Alberto Aguiar; de Oliveira, Luciano Fonseca Lemos; de Carvalho, Eduardo Elias Vieira; Simões, Marcus Vinicius; da Silva Meirelles, Lindolfo; Fazan, Rubens

    2015-01-01

    Heart failure induced by myocardial infarct (MI) attenuates the heart rate variability (HRV) and baroreflex sensitivity, which are important risk factors for life-threatening cardiovascular events. Therapies with mesenchymal stem cells (MSCs) have shown promising results after MI. However, the effects of MSCs on hemodynamic (heart rate and arterial pressure) variability and baroreflex sensitivity in chronic heart failure (CHF) following MI have not been evaluated thus far. Male Wistar rats received MSCs or saline solution intravenously 1 week after ligation of the left coronary artery. Control (noninfarcted) rats were also evaluated. MI size was assessed using single-photon emission computed tomography (SPECT). The left ventricular ejection fraction (LVEF) was evaluated using radionuclide ventriculography. Four weeks after MSC injection, the animals were anesthetized and instrumented for chronic ECG recording and catheters were implanted in the femoral artery to record arterial pressure. Arterial pressure and HRVs were determined in time and frequency domain (spectral analysis) while HRV was also examined using nonlinear methods: DFA (detrended fluctuation analysis) and sample entropy. The initial MI size was the same among all infarcted rats but was reduced by MSCs. CHF rats exhibited increased myocardial interstitial collagen and sample entropy combined with the attenuation of the following cardiocirculatory parameters: DFA indices, LVEF, baroreflex sensitivity, and HRV. Nevertheless, MSCs hampered all these alterations, except the LVEF reduction. Therefore, 4 weeks after MSC therapy was applied to CHF rats, MI size and myocardial interstitial fibrosis decreased, while baroreflex sensitivity and HRV improved. PMID:26059001

  20. Skeletal muscle electrical stimulation improves baroreflex sensitivity and heart rate variability in heart failure rats.

    PubMed

    Lazzarotto Rucatti, Ananda; Jaenisch, Rodrigo Boemo; Rossato, Douglas Dalcin; Bonetto, Jéssica Hellen Poletto; Ferreira, Janaína; Xavier, Leder Leal; Sonza, Anelise; Dal Lago, Pedro

    2015-12-01

    The goal of the current study was to evaluate the effects of electrical stimulation (ES) on the arterial baroreflex sensitivity (BRS) and cardiovascular autonomic control in rats with chronic heart failure (CHF). Male Wistar rats were designated to one of four groups: placebo sham (P-Sham, n=9), ES sham (ES-Sham, n=9), placebo CHF (P-CHF, n=9) or ES CHF (ES-CHF, n=9). The ES was adjusted at a low frequency (30 Hz), duration of 250 μs, with hold and rest time of 8s (4 weeks, 30 min/day, 5 times/week). It was applied on the gastrocnemius muscle with intensity to produce a visible muscle contraction. The rats assigned to the placebo groups performed the same procedures with the equipment turned off. The two-way ANOVA and the post hoc Student-Newman-Keuls tests (P<0.05) were used to data comparison. The BRS was higher in ES-Sham group compared to the P-Sham group and the ES-CHF group compared to the P-CHF group. ES was able to decrease heart rate sympatho-vagal modulation and peripheral sympathetic modulation in ES-CHF compared to P-CHF group. Interestingly, heart rate sympatho-vagal modulation was similar between ES-CHF and P-Sham groups. Thus, ES enhances heart rate parasympathetic modulation on heart failure (ES-CHF) compared to placebo (P-CHF), with consequent decrease of sympatho-vagal balance in the ES-CHF group compared to the P-CHF. The results show that a 4 week ES protocol in CHF rats enhances arterial BRS and cardiovascular autonomic control.

  1. Bluetooth(Registered Trademark) Heart Rate Monitors for Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, Roxanne E.; West, Michael R.; Kalogera, Kent L.; Hanson, Andrea M.

    2016-01-01

    Heart rate monitoring is required during exercise for crewmembers aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data is required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth® heart rate monitors (BT_HRM) and their ability to provide high quality heart rate data to monitor crew health on board ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT_HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) was worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT_RHM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the two data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. REULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6%error), followed by CS4 (3.3%error), CS3 (6.4%error), and CS2 (9.2%error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to get the best quality data. CS2 will be used in an

  2. Visual evoked potentials and heart rate during white noise stimulation.

    PubMed

    Lucchese, F; Mecacci, L

    1999-03-01

    Visual evoked potentials (VEPs) were recorded in 12 adult participants as a function of the temporal frequency of a phase-reversed checkerboard, with or without a simultaneously presented white noise. During the VEP recordings also the pulse rate was measured. VEP amplitude changed as function of temporal frequency, but it was not affected by noise. Pulse rate was stable during the session without noise, but it increased during the white noise stimulation at high temporal frequencies. Heart acceleration might be associated to conditions when processing at low levels of visual sensitivity (high temporal frequencies) is furthermore disturbed by interfering stimulation (noise).

  3. Coordinate-dependent diffusion coefficients: Decay rate in open quantum systems

    SciTech Connect

    Sargsyan, V. V.; Palchikov, Yu. V.; Antonenko, N. V.; Kanokov, Z.; Adamian, G. G.

    2007-06-15

    Based on a master equation for the reduced density matrix of an open quantum collective system, the influence of coordinate-dependent microscopical diffusion coefficients on the decay rate from a metastable state is treated. For various frictions and temperatures larger than a crossover temperature, the quasistationary decay rates obtained with the coordinate-dependent microscopical set of diffusion coefficients are compared with those obtained with the coordinate-independent microscopical set of diffusion coefficients and coordinate-independent and -dependent phenomenological sets of diffusion coefficients. Neglecting the coordinate dependence of diffusion coefficients, one can strongly overestimate or underestimate the decay rate at low temperature. The coordinate-dependent phenomenological diffusion coefficient in momentum are shown to be suitable for applications.

  4. Assessment of post-laparotomy pain in laboratory mice by telemetric recording of heart rate and heart rate variability

    PubMed Central

    Arras, Margarete; Rettich, Andreas; Cinelli, Paolo; Kasermann, Hans P; Burki, Kurt

    2007-01-01

    Background Pain of mild to moderate grade is difficult to detect in laboratory mice because mice are prey animals that attempt to elude predators or man by hiding signs of weakness, injury or pain. In this study, we investigated the use of telemetry to identify indicators of mild-to-moderate post-laparotomy pain. Results Adult mice were subjected to laparotomy, either combined with pain treatment (carprofen or flunixin, 5 mg/kg s/c bid, for 1 day) or without pain relief. Controls received anesthesia and analgesics or vehicle only. Telemetrically measured locomotor activity was undisturbed in all animals, thus confirming that any pain experienced was of the intended mild level. No symptoms of pain were registered in any of the groups by scoring the animals' outer appearance or spontaneous and provoked behavior. In contrast, the group receiving no analgesic treatment after laparotomy demonstrated significant changes in telemetry electrocardiogram recordings: increased heart rate and decreased heart rate variability parameters pointed to sympathetic activation and pain lasting for 24 hours. In addition, core body temperature was elevated. Body weight and food intake were reduced for 3 and 2 days, respectively. Moreover, unstructured cage territory and destroyed nests appeared for 1–2 days in an increased number of animals in this group only. In controls these parameters were not affected. Conclusion In conclusion, real-time telemetric recordings of heart rate and heart rate variability were indicative of mild-to-moderate post-laparotomy pain and could define its duration in our mouse model. This level of pain cannot easily be detected by direct observation. PMID:17683523

  5. Skinfold thickness is related to cardiovascular autonomic control as assessed by heart rate variability and heart rate recovery.

    PubMed

    Esco, Michael R; Williford, Henry N; Olson, Michele S

    2011-08-01

    The purpose of this study was to determine if heart rate recovery (HRR) and heart rate variability (HRV) are related to maximal aerobic fitness and selected body composition measurements. Fifty men (age = 21.9 ± 3.0 years, height = 180.8 ± 7.2 cm, weight = 80.4 ± 9.1 kg, volunteered to participate in this study. For each subject, body mass index (BMI), waist circumference (WC), and the sum of skinfolds across the chest, abdomen, and thigh regions (SUMSF) were recorded. Heart rate variability (HRV) was assessed during a 5-minute period while the subjects rested in a supine position. The following frequency domain parameters of HRV were recorded: normalized high-frequency power (HFnu), and low-frequency to high-frequency power ratio (LF:HF). To determine maximal aerobic fitness (i.e., VO2max), each subject performed a maximal graded exercise test on a treadmill. Heart rate recovery was recorded 1 (HRR1) and 2 (HRR2) minutes during a cool-down period. Mean VO2max and BMI for all the subjects were 49.5 ± 7.5 ml·kg(-1)·min(-1) and 24.7 ± 2.2 kg·m(-2), respectively. Although VO2max, WC, and SUMSF was each significantly correlated to HRR and HRV, only SUMSF had a significant independent correlation to HRR1, HRR2, HFnu, LF:HF (p < 0.01). The results of the regression procedure showed that SUMSF accounted for the greatest variance in HRR1, HRR2, HFnu, and LF:HF (p < 0.01). The results of this study suggest that cardiovascular autonomic modulation is significantly related to maximal aerobic fitness and body composition. However, SUMSF appears to have the strongest independent relationship with HRR and HRV, compared to other body composition parameters and VO2max.

  6. Predictive value of casual ECG-based resting heart rate compared with resting heart rate obtained from Holter recording.

    PubMed

    Carlson, Nicholas; Dixen, Ulrik; Marott, Jacob L; Jensen, Magnus T; Jensen, Gorm B

    2014-03-01

    Elevated resting heart rate (RHR) is associated with cardiovascular mortality and morbidity. Assessment of heart rate (HR) from Holter recording may afford a more precise estimate of the effect of RHR on cardiovascular risk, as compared to casual RHR. Comparative analysis was carried out in an age-stratified subsample of 131 subjects in the Copenhagen City Heart Study (CCHS). Casual RHR was assessed from electrocardiograms recorded during clinical assessment. Hourly daytime HRs were mapped by Holter recording. Holter RHR was defined as the average of the lowest 3 hourly HRs recorded and mean HR calculated from all daytime HRs. Follow-up was recorded from public registers. Outcome measure was hazard rate for the combined endpoint of cardiovascular mortality, non-fatal heart failure and non-fatal acute myocardial infarction. Comparison of casual RHR, Holter RHR and mean HR by Multivariate Cox regression was performed. A total of 57 composite endpoints occurred during 17.1 years of follow-up. Regression analysis suggests correlation between Casual RHR and Holter RHR. Multivariate Cox regression analysis adjusted for gender and age demonstrated hazard rates of 1.02 (p = 0.079) for casual RHR, 1.04 (p = 0.036*) for Holter RHR, and 1.03 (p = 0.093) for mean HR for each 10 beat increment in HR. In a comparative analysis on the correlation and significance of differing RHR measurement modalities RHR measured by 24-hour Holter recording was found to be marginally superior as a predictor of cardiovascular morbidity and mortality. The results presented here do not however warrant the abandonment of a tested epidemiological variable.

  7. Acute exposure to environmental tobacco smoke and heart rate variability.

    PubMed Central

    Pope, C A; Eatough, D J; Gold, D R; Pang, Y; Nielsen, K R; Nath, P; Verrier, R L; Kanner, R E

    2001-01-01

    Environmental tobacco smoke (ETS) has been associated with cardiovascular mortality. Pathophysiologic pathways leading from ETS exposure to cardiopulmonary disease are still being explored. Reduced cardiac autonomic function, as measured by heart rate variability (HRV), has been associated with cardiac vulnerability and may represent an important pathophysiologic mechanism linking ETS and risk of cardiac mortality. In this study we evaluated acute ETS exposure in a commercial airport with changes in HRV in 16 adult nonsmokers. We conducted ambulatory electrocardiographic (ECG) monitoring for 8-hr periods while participants alternated 2 hr in nonsmoking and smoking areas. Nicotine and respirable suspended particle concentrations and participants' blood oxygen saturation were also monitored. We calculated time and frequency domain measures of HRV for periods in and out of the smoking area, and we evaluated associations with ETS using comparative statistics and regression modeling. ETS exposure was negatively associated with all measures of HRV. During exposure periods, we observed an average decrement of approximately 12% in the standard deviation of all normal-to-normal heart beat intervals (an estimate of overall HRV). ETS exposures were not associated with mean heart rate or blood oxygen saturation. Altered cardiac autonomic function, assessed by decrements in HRV, is associated with acute exposure to ETS and may be part of the pathophysiologic mechanisms linking ETS exposure and increased cardiac vulnerability. PMID:11485870

  8. Ivabradine in acute coronary syndromes: Protection beyond heart rate lowering.

    PubMed

    Niccoli, Giampaolo; Borovac, Josip Anđelo; Vetrugno, Vincenzo; Camici, Paolo G; Crea, Filippo

    2017-06-01

    Ivabradine is a heart rate reducing agent that exhibits anti-ischemic effects through the inhibition of funny electrical current in the sinus node resulting in heart rate reduction, thus enabling longer diastolic perfusion time, and reduced myocardial oxygen consumption without detrimental changes in arterial blood pressure, coronary vasomotion, and ventricular contractility. The current guideline-based clinical use of Ivabradine is reserved for patients with stable angina pectoris who cannot tolerate or whose symptoms are inadequately controlled with beta blockers. In patients with chronic heart failure and reduced ejection fraction, Ivabradine has demonstrated beneficial effects in improving clinical outcomes when added to conventional therapy. However, the role of Ivabradine in acute coronary syndromes has not been established. Based on the results from some relevant preclinical studies and a limited amount of clinical data that were reported recently, the role of Ivabradine in acute ischemic events warrants further investigation. The aim of this review is to provide an overview of the available literature on the potential role of Ivabradine in the clinical context of acute coronary syndromes. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Is there a relationship between obesity, heart rate variability and inflammatory parameters in heart failure?

    PubMed

    Taçoy, Gülten; Açikgöz, Kadri; Kocaman, Sinan Altan; Ozdemir, Murat; Cengel, Atiye

    2010-02-01

    To investigate the effect of body mass index (BMI) on heart rate variability (HRV) and inflammatory parameters in patients with heart failure. We analyzed 55 consecutive patients (mean age, 63.5 +/- 12.8 years; male/female, 39/16) with symptomatic left ventricular systolic (ejection fraction <45%) heart failure. The participants were classified into three categories according to BMI: lean (BMI < 25 kg/m2), overweight (BMI = 25-29.9 kg/m2) and obese (BMI >or= 30 kg/m2). The cause of heart failure was mainly ischemic heart disease (75%) with mean ejection fraction 30 +/- 7%. Plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) and C-reactive protein levels were measured, and time-domain HRV indices were determined on Holter electrocardiogram. The relationship between HRV indices and laboratory, inflammatory and echocardiographic parameters was investigated with correlation analysis. Age, sex, clinical characteristics (hypertension, diabetes mellitus, dyslipidemia, family history, smoking) were similar between groups. BMI was inversely correlated with NT-pro BNP levels (P = 0.001). HRV indices did not differ between groups. Correlation analysis demonstrated the relationship between HRV indices and fasting blood glucose (SDNN, SDANN, SDNNI, root mean square successive differences, VTI), C-reactive protein (SDANN, SDNNI, VTI), pulmonary artery pressure (SDNN, SDANN, VTI) levels. In systolic heart failure patients a higher BMI is associated with decreased NT-proBNP levels. Although HRV indices were not different between groups, inflammatory parameters, fasting blood glucose and pulmonary artery pressure were correlated with them.

  10. Respiratory modulation and baroreflex control of heart rate in space

    NASA Astrophysics Data System (ADS)

    Verheyden, Bart; Couckuyt, Kurt; Liu, Jiexin; Aubert, Andre

    During everyday life, gravity constantly stresses the human circulation by diminishing venous return in the upright position. This induces baroreflex-mediated cardiovascular adjustments that are aimed to prevent the blood pressure from falling. In weightlessness, gravitational pressure gradients do not arise in the circulation so that baroreflex function remains chronically unchallenged. This may contribute to the development of post spaceflight orthostatic intolerance. The purpose of this study was to evaluate respiratory modulation and baroreflex control of heart rate after a week of weightlessness in space. We tested the hypothesis that cardiovascular control in space will be similar to the baseline supine condition on Earth. We studied nine male cosmonauts during seven different space missions aboard the ISS (age 40 - 52 yrs, height 1.69 - 1.85 m, weight 67 - 90 kg). Data collection was performed between 30 and 45 days before launch in the standing and supine positions, and after 8 days in space. Cosmonauts were carefully trained to perform in-flight data collection by themselves. They were instructed to pace their breathing to a fixed rate of 12 breaths per minute (0.2 Hz) for a total duration of 3 minutes. The electrocardiogram and beat-by-beat finger arterial blood pressure were recorded at 1-kHz sample rate. Respiratory rate was evaluated using an abdominal pressure sensor. We used power spectral analysis to calculate respiratory sinus arrhythmia (RSA) as well as the low-frequency (0.04 - 0.15 Hz) powers of spontaneous oscillations in heart rate and systolic blood pressure. Baroreflex sensitivity (BRS) was estimated in the time domain using cross-correlation analysis. As expected, there was a rise in heart rate upon assuming the standing position before space- flight (59 ± 6 to 79 ± 11 beats per min; p ¡ 0.001). This was accompanied by an increase in mean arterial blood pressure (84 ± 6 to 93 ± 6 mmHg; p ¡ 0.001). Standing up further induced a marked

  11. Characterizing heart rate variability by scale-dependent Lyapunov exponent

    NASA Astrophysics Data System (ADS)

    Hu, Jing; Gao, Jianbo; Tung, Wen-wen

    2009-06-01

    Previous studies on heart rate variability (HRV) using chaos theory, fractal scaling analysis, and many other methods, while fruitful in many aspects, have produced much confusion in the literature. Especially the issue of whether normal HRV is chaotic or stochastic remains highly controversial. Here, we employ a new multiscale complexity measure, the scale-dependent Lyapunov exponent (SDLE), to characterize HRV. SDLE has been shown to readily characterize major models of complex time series including deterministic chaos, noisy chaos, stochastic oscillations, random 1/f processes, random Levy processes, and complex time series with multiple scaling behaviors. Here we use SDLE to characterize the relative importance of nonlinear, chaotic, and stochastic dynamics in HRV of healthy, congestive heart failure, and atrial fibrillation subjects. We show that while HRV data of all these three types are mostly stochastic, the stochasticity is different among the three groups.

  12. Nonstationarity and 1/f noise characteristics in heart rate.

    PubMed

    Pilgram, B; Kaplan, D T

    1999-01-01

    The power spectrum of human heart rate (HR) measured over 24 h exhibits "power-law" 1/f alpha-type spectral behavior with alpha approximately 1. We investigate possible nonstationarity in time of the exponent alpha using maximum likelihood estimation, which allows relatively short data segments to be used. Examination of 24-h HR records from ambulatory normal and congestive heart failure (CHF) subjects indicates that the power-law structure of HR is nonstationary. In addition, alpha varies with time scale and is different for normal (alpha approximately 1) and CHF (alpha approximately 1.5) subjects. Simulations suggest that a possible mechanism underlying the observed power-law spectrum may be a switching between values of alpha near zero (white noise) and near two (Brownian motion). This mechanism generates power-law forms quantitatively similar to CHF subjects when the switching occurs very rapidly and similar to normal subjects when the switching is less rapid.

  13. Reading multifractal spectra: Aging by multifractal analysis of heart rate

    NASA Astrophysics Data System (ADS)

    Makowiec, D.; Rynkiewicz, A.; Gałaska, R.; Wdowczyk-Szulc, J.; Żarczyńska-Buchowiecka, M.

    2011-06-01

    The method of effective reading of multifractal properties is proposed. The method consists in the analysis of a given signal together with the analysis of an integrated signal. A practical way to separate monofractal-type signals from other signals is given. The method is applied to 24-hour ECG recordings of RR-interbeat intervals to assess the effect of aging on autonomic regulation of the heart in healthy adults. Heart rate variability is evaluated by multifractal analysis in the VLF band. A switch from mono- to multifractality is observed between diurnal and nocturnal parts of series in the group of young adults. With aging the multifractal structure of nocturnal signals declines. The observed changes can be related to the circadian alternation in the central mechanisms controlling the cardiovascular system which becomes impaired with advance in age in human. Indices for age impairment of autonomic regulation are proposed.

  14. Heart rate and outcome in patients with cardiovascular disease undergoing major noncardiac surgery.

    PubMed

    Biccard, B M

    2008-07-01

    There is an increasing awareness that an elevated resting heart rate is associated with increased all-cause mortality in the general population and that this may be an independent coronary risk factor This review was undertaken to determine whether heart rate is predictive of increased mortality and major morbidity in noncardiac surgical patients and whether heart rate manipulation improves perioperative outcome. A search of Medline from 1966 until October 2007 was conducted using the terms "heart rate", "surgery", "cardiac", "morbidity", "mortality" and "perioperative". The main findings were that an elevated perioperative heart rate, an absolute increase in heart rate and heart rate lability are independent predictors of both short- and long-term adverse outcomes in patients at cardiovascular risk undergoing major noncardiac surgery. Although prospective nonrandomised and retrospective data suggest heart rate control improves perioperative outcome, there is conflicting evidence from randomised trials that perioperative heart rate control improves outcome. This may be because drug-associated bradycardia influences mortality in the perioperative period. Further studies reporting the absolute heart rate, the absolute change of heart rate and the time period of the observations are needed to identify 'early warning systems', which may allow earlier triage and improved outcome. Enthusiasm for this approach must be tempered by the appreciation that a J-shaped relationship probably exists between heart rate and morbidity, particularly following bradycardic therapy. Therefore, any bradycardic manipulation of heart rate in the perioperative period must be accompanied by simultaneous attention to other physiological variables associated with increased morbidity and mortality.

  15. Differential effects of heart rate modification training on college students, older males, and patients with ischemic heart disease.

    PubMed

    Lang, P J; Troyer, W G; Twentyman, C T; Gatchel, R J

    1975-01-01

    Seventy male subjects participated in a six session study of feedback-mediated heart rate modification. Three groups of subjects were compared: (1) college students, (2) patients with ischemic heart disease, and (3) healthy males, age-matched to the patients. The groups did not differ in heart rate during rest or in response to a perceptual-motor tracking task. However, the college students produced significantly larger changes in cardiac rate than the other two groups when instructed to modify heart rate (speed or slow) and provided with exteroceptive feedback. The patients showed the poorest overall feedback performance. These differences between groups were greater for speeding than for the slowing task. Relationships were explored between feedback performance and resting heart and respiration rate, drug regime, and personality questionnaires. The results were consistent with the hypothesis that interdependence between psychological stimuli and cardiovascular events is reduced in heart disease.

  16. Breathing rates and heart rate spectrograms regarding body position in normal subjects.

    PubMed

    Avbelj, Viktor; Kalisnik, Jurij-Matija; Trobec, Roman; Gersak, Borut

    2003-05-01

    The right lateral body position has been proposed as an effective vagal enhancer. However, the possibility of breathing affecting heart rate power spectra in different body positions has not been assessed. The level of vagal modulation in various body positions in normal subjects was estimated by calculating heart rate power spectra. The results suggest that the levels of vagal modulation do not necessarily reflect a change due to assuming different body position, but might be the consequence of changed breathing patterns. Before adopting the right lateral body position as vagal enhancing, the contribution of varying breathing pattern should be eliminated.

  17. Heart dimensions may influence the occurrence of the heart rate deflection point in highly trained cyclists

    PubMed Central

    Lucia, A.; Carvajal, A.; Boraita, A.; Serratosa, L.; Hoyos, J.; Chicharro, J. L.

    1999-01-01

    OBJECTIVES: To determine whether the heart rate (HR) response to exercise in 21 highly trained cyclists (mean (SD) age 25 (3) years) was related to their heart dimensions. METHODS: Before performing an incremental exercise test involving a ramp protocol with workload increases of 25 W/min, each subject underwent echocardiographic evaluation of the following variables: left ventricular end diastolic internal diameter (LVIDd), left ventricular posterior wall thickness at end diastole (LVPWTd), interventricular septal wall thickness at end diastole (IVSTd), left ventricular mass index (LVMI), left atrial dimension (LAD), longitudinal left atrial (LLAD) and right atrial (LRAD) dimensions, and the ratio of early to late (E/A) diastolic flow velocity. RESULTS: The HR response showed a deflection point (HRd) at about 85% VO2MAX in 66.7% of subjects (D group; n = 14) and was linear in 33.3% (NoD group; n = 7). Several echocardiographic variables (LVMI, LAD, LLAD, LRAD) indicative of heart dimensions were similar in each group. However, mean LPWTd (p<0.01) and IVSTd (p<0.05) values were significantly higher in the D group. Finally, no significant difference between groups was found with respect to the E/A. CONCLUSIONS: The HR response is curvilinear during incremental exercise in a considerable number of highly trained endurance athletes-that is, top level cyclists. The departure of HR increase from linearity may predominantly occur in athletes with thicker heart walls. 


 PMID:10597846

  18. Terminology and Methodology Related to the Use of Heart Rate Responsivity in Infancy Research

    ERIC Educational Resources Information Center

    Woodcock, James M.

    1971-01-01

    Methodological problems in measuring and interpreting infantile heart rate reactivity in research are discussed. Various ways of describing cardiac activity are listed. Attention is given to the relationship between resting state and heart rate responsivity. (Author/WY)

  19. Terminology and Methodology Related to the Use of Heart Rate Responsivity in Infancy Research

    ERIC Educational Resources Information Center

    Woodcock, James M.

    1971-01-01

    Methodological problems in measuring and interpreting infantile heart rate reactivity in research are discussed. Various ways of describing cardiac activity are listed. Attention is given to the relationship between resting state and heart rate responsivity. (Author/WY)

  20. Comparison of rate assessment between resting heart rate and 24-hour Holter monitoring in patients with chronic atrial fibrillation.

    PubMed

    Srisukwattana, Akanis; Krittayaphong, Rungroj

    2012-02-01

    Target heart rate in rate control strategy has been proposed by the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study. There is limited data on the correlation of measured heart rate at rest and during Holter monitoring. To evaluate the proportion of achieved target heart rate between resting heart rate measuring and 24-hour Holter monitoring in patients with chronic atrial fibrillation who receive rate control strategy. Patients with chronic atrial fibrillation who archived target resting heart rate under rate control strategy at Siriraj Hospital and who underwent 24-hour Holter monitoring were studied to evaluate the correlation between two methods of heart rate control. 47 patients were enrolled. Underlying cardiac conditions were as follows: hypertensive heart disease 44.7%, valvular heart disease 25%, coronary artery disease 17% and dilated cardiomyopathy 12.8%. There were 10 patients (21.3%) whose achieving target resting heart rate was not correlated with 24-hour Holter monitoring. Three patients (6.4%) underwent permanent pacemaker implantation due to sick sinus syndrome (SSS) or tachycardia-bradycardia syndrome. In chronic atrial fibrillation patients that receive rate control strategy, evaluation of only resting heart rate might not be enough for long-term evaluation and treatment and 24-hour monitoring may be an additional helpful test in order to more precisely adjust medication for long-term treatment and detection of SSS.

  1. Association between atrial fibrillatory rate and heart rate variability in patients with atrial fibrillation and congestive heart failure.

    PubMed

    Corino, Valentina D A; Cygankiewicz, Iwona; Mainardi, Luca T; Stridh, Martin; Vasquez, Rafael; Bayes de Luna, Antonio; Holmqvist, Fredrik; Zareba, Wojciech; Platonov, Pyotr G

    2013-01-01

    Even if atrial fibrillatory rate (AFR) has been related to clinical outcome in patients with atrial fibrillation (AF), its relation with ventricular response has not been deeply studied. The aim of this study was to investigate the relation between AFR and RR series variability in patients with AF. Twenty-minute electrocardiograms in orthogonal leads were processed to extract AFR, using spatiotemporal QRST cancellation and time frequency analysis, and RR series in 127 patients (age 69 ± 11 years) with congestive heart failure (NYHA II-III) enrolled in the MUSIC study (MUerte Subita en Insufficiencia Cardiaca). Heart rate variability and irregularity were assessed by time domain parameters and entropy-based indices, respectively and their correlation with AFR investigated. Variability measures seem not to be related to AFR, while irregularity measures do. A significant correlation between AFR and variability parameters of heart rate variability during AF was found only in patients not treated with antiarrhythmics drugs (correlation = 0.56 P < 0.05 for pNN50), while this correlation was lost in patients taking rate- or rhythm-control drugs. A significant positive correlation between AFR and indices of RR irregularity was found, showing that a higher AFR is related to a less organized RR series (correlation = 0.33 P < 0.05 for regularity index for all patients, correlation increased in subgroups of patients treated with the same drug). These results suggest that a higher AFR is associated with a higher degree of irregularity of ventricular response that is observed regardless of the use of rate-controlling drugs. ©2012, Wiley Periodicals, Inc.

  2. Effect of Cardiac Rehabilitation Program on Heart Rate Recovery in Coronary Heart Disease.

    PubMed

    Mahdavi Anari, Leila; Ghanbari-Firoozabadi, Mahdieh; Ansari, Zahra; Emami, Mahmoud; Vafaii Nasab, Mohammadreza; Nemaiande, Mahdieh; Boostany, Fatemeh; Neishaboury, Mohamadreza

    2015-10-27

    It has been suggested that the autonomic system function and the metabolic syndrome can significantly affect patients' survival. The aim of the current study was to investigate the impact of the cardiac rehabilitation program on the autonomic system balance in patients with coronary artery disease. Patients with a previous diagnosis of coronary artery disease who were referred to the Cardiovascular Rehabilitation Center of Afshar Hospital (Yazd, Iran) between March and November 2011 were enrolled. All the patients participated in rehabilitation sessions 3 times a week for 12 weeks. Heart rate recovery (HRR) was measured as an indicator of the autonomic system balance. In order to calculate HRR, the maximum heart rate during the exercise test was recorded. At the end of the exercise test, the patients were asked to sit down without having a cooldown period and their heart rate was recorded again after 1 minute. The difference between these 2 measurements was considered as HRR. A total of 108 patients, including 86 (79.6%) men and 22 (20.4%) women, completed the rehabilitation course. The mean age of the study participants was 58.25 ± 9.83 years. A statistically significant improvement was observed in HRR (p value = 0.040). Significant declines were also observed in the patients' waist circumference (p value < 0.001) and systolic and diastolic blood pressures (p value = 0.018 and 0.003, respectively). A decreasing trend was observed in the patients' body mass index, but it failed to reach statistical significance (p value = 0.063). No statistically meaningful changes were noted in fasting blood glucose (p value = 0.171), high-density lipoprotein (p value = 0.070), or triglyceride concentrations (p value = 0.149). The cardiac rehabilitation program may help to improve HRR and several components of the metabolic syndrome in patients with coronary heart disease.

  3. Pilot Program to Improve Self-Management of Patients with Heart Failure by Redesigning Care Coordination

    PubMed Central

    Shaw, Jessica D.; O'Neal, Daniel J.; Siddharthan, Kris; Neugaard, Britta I.

    2014-01-01

    Objectives. We tested both an educational and a care coordination element of health care to examine if better disease-specific knowledge leads to successful self-management of heart failure (HF). Background. The high utilization of health care resources and poor patient outcomes associated with HF justify tests of change to improve self-management of HF. Methods. This prospective study tested two components of the Chronic Care Model (clinical information systems and self-management support) to improve outcomes in the self-management of HF among patients who received intensive education and care coordination during their acute care stay. A postdischarge follow-up phone call assessed their knowledge of HF self-management compared to usual care patients. Results. There were 20 patients each in the intervention and usual care groups. Intervention patients were more likely to have a scale at home, write down their weight, and practice new or different health behaviors. Conclusion. Patients receiving more intensive education knew more about their disease and were better able to self-manage their weight compared to patients receiving standard care. PMID:24864206

  4. Omega-3 Polyunsaturated Fatty Acids and Heart Rate Variability

    PubMed Central

    Christensen, Jeppe Hagstrup

    2011-01-01

    Omega-3 polyunsaturated fatty acids (PUFA) may modulate autonomic control of the heart because omega-3 PUFA is abundant in the brain and other nervous tissue as well as in cardiac tissue. This might partly explain why omega-3 PUFA offer some protection against sudden cardiac death (SCD). The autonomic nervous system is involved in the pathogenesis of SCD. Heart rate variability (HRV) can be used as a non-invasive marker of cardiac autonomic control and a low HRV is a predictor for SCD and arrhythmic events. Studies on HRV and omega-3 PUFA have been performed in several populations such as patients with ischemic heart disease, patients with diabetes mellitus, patients with chronic renal failure, and in healthy subjects as well as in children. The studies have demonstrated a positive association between cellular content of omega-3 PUFA and HRV and supplementation with omega-3 PUFA seems to increase HRV which could be a possible explanation for decreased risk of arrhythmic events and SCD sometimes observed after omega-3 PUFA supplementation. However, the results are not consistent and further research is needed. PMID:22110443

  5. Optimum Heart Rate to Minimize Pulsatile External Cardiac Power

    NASA Astrophysics Data System (ADS)

    Pahlevan, Niema; Gharib, Morteza

    2011-11-01

    The workload on the left ventricle is composed of steady and pulsatile components. Clinical investigations have confirmed that an abnormal pulsatile load plays an important role in the pathogenesis of left ventricular hypertrophy (LVH) and progression of LVH to congestive heart failure (CHF). The pulsatile load is the result of the complex dynamics of wave propagation and reflection in the compliant arterial vasculature. We hypothesize that aortic waves can be optimized to reduce the left ventricular (LV) pulsatile load. We used an in-vitro experimental approach to investigate our hypothesis. A unique hydraulic model was used for in-vitro experiments. This model has physical and dynamical properties similar to the heart-aorta system. Different compliant models of the artificial aorta were used to test the hypothesis under various aortic rigidities. Our results indicate that: i) there is an optimum heart rate that minimizes LV pulsatile power (this is in agreement with our previous computational study); ii) introducing an extra reflection site at the specific location along the aorta creates constructive wave conditions that reduce the LV pulsatile power.

  6. Elevated resting heart rate is associated with the metabolic syndrome

    PubMed Central

    Rogowski, Ori; Steinvil, Arie; Berliner, Shlomo; Cohen, Michael; Saar, Nili; Kliuk Ben-Bassat, Orit; Shapira, Itzhak

    2009-01-01

    Background Increased resting heart rate (RHR) may be associated with increased cardiovascular morbidity. Our aim was to explore the possibility that increased RHR is associated with the prevalence of the metabolic syndrome (MetS) in a sample of apparently healthy individuals and those with cardiovascular risk factors. Methods We performed a cross-sectional analysis in a large sample of apparently healthy individuals who attended a general health screening program and agreed to participate in our survey. We analyzed a sample of 7706 individuals (5106 men and 2600 women) with 13.2% of men and 8.9% of the women fulfilling the criteria for the MetS. The participants were divided into quintiles of resting heart rate. Multiple adjusted odds ratio was calculated for having the MetS in each quintile compared to the first. Results The multi-adjusted odds for the presence of the MetS increased gradually from an arbitrarily defined figure of 1.0 in the lowest RHR quintile (<60 beats per minute (BPM) in men and <64 BPM in women) to 4.1 and 4.2 in men and women respectively in the highest one (≥80 BPM in men and ≥82 BPM in women). Conclusion Raised resting heart rate is significantly associated with the presence of MetS in a group of apparently healthy individuals and those with an atherothrombotic risk. The strength of this association supports the potential presence of one or more shared pathophysiological mechanisms for both RHR and the MetS. PMID:19828043

  7. Spectral analysis of heart rate variability during trigger point acupuncture.

    PubMed

    Kitagawa, Yoji; Kimura, Kenichi; Yoshida, Sohei

    2014-06-01

    To clarify changes in the cardiovascular autonomic nervous system function due to trigger point acupuncture, we evaluated differences in responses between acupuncture at trigger points and those at other sites using spectral analysis of heart rate variability. Subjects were 35 healthy men. Before measurements began the subjects were assigned to a trigger point acupuncture or control group based on the presence/absence of referred pain on applying pressure to a taut band within the right tibialis anterior muscle. The measurements were conducted in a room with a temperature of 25°C, with subjects in a long sitting position after 10 min rest. Acupuncture needles were retained for 10 min at two sites on the right tibialis anterior muscle. ECG was performed simultaneously with measurements of blood pressure and the respiratory cycle. Based on the R-R interval on the ECG, frequency analysis was performed, low-frequency (LF) and high-frequency (HF) components were extracted and the ratio of LF to HF components (LF/HF) was evaluated. The trigger point acupuncture group showed a transient decrease in heart rate and an increase in the HF component but no significant changes in LF/HF. In the control group, no significant changes were observed in heart rate, the HF component or LF/HF. There were no consistent changes in systolic or diastolic blood pressure in either group. These data suggest that acupuncture stimulation of trigger points of the tibialis anterior muscle transiently increases parasympathetic nerve activity. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  8. Elevated resting heart rate is associated with the metabolic syndrome.

    PubMed

    Rogowski, Ori; Steinvil, Arie; Berliner, Shlomo; Cohen, Michael; Saar, Nili; Ben-Bassat, Orit Kliuk; Shapira, Itzhak

    2009-10-14

    Increased resting heart rate (RHR) may be associated with increased cardiovascular morbidity. Our aim was to explore the possibility that increased RHR is associated with the prevalence of the metabolic syndrome (MetS) in a sample of apparently healthy individuals and those with cardiovascular risk factors. We performed a cross-sectional analysis in a large sample of apparently healthy individuals who attended a general health screening program and agreed to participate in our survey. We analyzed a sample of 7706 individuals (5106 men and 2600 women) with 13.2% of men and 8.9% of the women fulfilling the criteria for the MetS. The participants were divided into quintiles of resting heart rate. Multiple adjusted odds ratio was calculated for having the MetS in each quintile compared to the first. The multi-adjusted odds for the presence of the MetS increased gradually from an arbitrarily defined figure of 1.0 in the lowest RHR quintile (<60 beats per minute (BPM) in men and <64 BPM in women) to 4.1 and 4.2 in men and women respectively in the highest one (>or=80 BPM in men and >or=82 BPM in women). Raised resting heart rate is significantly associated with the presence of MetS in a group of apparently healthy individuals and those with an atherothrombotic risk. The strength of this association supports the potential presence of one or more shared pathophysiological mechanisms for both RHR and the MetS.

  9. Playing a violent television game affects heart rate variability.

    PubMed

    Ivarsson, Malena; Anderson, Martin; Akerstedt, Torbjörn; Lindblad, Frank

    2009-01-01

    To investigate how playing a violent/nonviolent television game during the evening affects sympathetic and parasympathetic reactions during and after playing as well as sleep quality during the night after playing. In total, 19 boys, 12-15 years of age, played television games on two occasions in their homes and participated once without gaming. Heart rate, heart rate variability (HRV) and physical activity were measured during gaming/participating and the night to follow using a portable combined heart rate and movement sensor. A sleep diary and questionnaires about gaming experiences and session-specific experiences were filled in. Criteria for Selection of Games: Violent game involves/rewards direct physical violence (no handguns) against another person, and nonviolent game involves/rewards no violence; same game design ('third-person game'); conducted in the same manner; no differences concerning motor activity; similar sound and light effects; no sexual content, violence against women or racial overtones. During violent (vs. nonviolent) gaming, there was significantly higher activity of the very low frequency component of the HRV and total power. During the night after playing, very low frequency, low frequency and high frequency components were significantly higher during the violent (vs. nonviolent) condition, just as total power. There were no significant differences between the three conditions (violent/nonviolent/no gaming) with respect to an index reflecting subjectively perceived sleep difficulties. Nor was there any difference between violent and nonviolent condition for any single sleep item. Violent gaming induces different autonomic responses in boys compared to nonviolent gaming--during playing and during the following night--suggesting different emotional responses. Subjectively perceived sleep quality is not influenced after a single gaming experience. Future studies should address the development of the autonomic balance after gaming over longer

  10. Noisy fluctuation of heart rate indicates cardiovascular system instability.

    PubMed

    Fortrat, Jacques-Olivier; Baum, Charlotte; Jeanguillaume, Christian; Custaud, Marc-Antoine

    2013-09-01

    Heart rate spontaneously fluctuates despite homeostatic regulatory mechanisms to stabilize it. Harmonic and fractal fluctuations have been described. Non-harmonic non-fractal fluctuation has not been studied because it is usually thought that it is caused by apparatus noise. We hypothesized that this fluctuation looking like apparatus noise (that we call "noisy fluctuation") is linked to challenged blood pressure stabilization and not to apparatus noise. We assessed noisy fluctuation by quantifying the small and fastest beat-to-beat fluctuation of RR-interval by means of spectral analysis (Nyquist power of heart rate variability: nyHRV) after filtering out its fractal component. We observed nyHRV in healthy supine subjects and in patients with vasovagal symptoms. We challenged stabilization of blood pressure by upright posture (by means of a head-up tilt table test). Head-up position on the tilt table dramatically decreased nyHRV (0.128 ± 0.063 vs. 0.004 ± 0.002, p < 0.01) in healthy subjects (n = 12). Head-up position also decreased nyHRV in patients without vasovagal symptoms (n = 24; 0.220 ± 0.058 vs. 0.034 ± 0.015, p < 0.05), but not in patients with vasovagal symptoms during a head-up tilt table test (age and sex paired, 0.103 ± 0.041 vs. 0.122 ± 0.069, not significant). Heart rate variability includes a physiological non-harmonic non-fractal noisy fluctuation. This noisy fluctuation indicates low engagement of regulatory mechanisms because it disappears when the cardiovascular system is challenged (upright posture). It also indicates cardiovascular instability because it does not disappear in upright patients before vasovagal syncope, a transient failure of cardiovascular regulation.

  11. [Heart rate variability and physical exercise. Current status].

    PubMed

    Hottenrott, Kuno; Hoos, Olaf; Esperer, Hans Dieter

    2006-09-01

    Heart rate variability (HRV) has long been used in risk stratification for sudden cardiac death and diabetic autonomic neuropathy. In recent years, both time and frequency domain indices of HRV also gained increasing interest in sports and training sciences. In these fields, HRV is currently used for the noninvasive assessment of autonomic changes associated with short-term and long-term endurance exercise training in both leisure sports activity and high-performance training. Furthermore, HRV is being investigated as a diagnostic marker of overreaching and overtraining.A large body of evidence shows that, in healthy subjects and cardiovascular patients of all ages (up to an age of 70 years), regular aerobic training usually results in a significant improvement of overall as well as instantaneous HRV. These changes, which are accompanied by significant reductions in heart rates both at rest and during submaximal exercise, reflect an increase in autonomic efferent activity and a shift in favor of enhanced vagal modulation of the cardiac rhythm. Regular aerobic training of moderate volume and intensity over a minimum period of 3 months seems to be necessary to ensure these effects, which might be associated with a prognostic benefit regarding overall mortality.At present, available data does not allow for final conclusions with respect to the usefulness of traditional HRV indices in assessing an individual's exercise performance and monitoring training load. The discrepant results published so far are due to several factors including insufficient study size and design, and different HRV methods. Large-sized and prospectively designed studies are necessary for clarification. It also remains to be seen, whether the traditional HRV indices prove useful in the diagnosis of overreaching and overtraining. Preliminary results, though promising, need to be confirmed in larger cohorts.A basic problem in HRV analysis is nonstationarity of the heart rate signal, which holds

  12. Relationship between exercise heart rate and music tempo preference.

    PubMed

    Karageorghis, Costas I; Jones, Leighton; Low, Daniel C

    2006-06-01

    The present study examined the predicted positive and linear relationship (Iwanaga, 1995a, 1995b) between exercise heart rate and music tempo preference. Initially, 128 undergraduate students (M age = 20.0 years, SD = 0.9) were surveyed to establish their three favorite music artists. A separate experimental group of 29 undergraduates (M age = 20.3 years, SD = 1.2) selected the music of a single artist from the three highest-rated artists from the earlier survey. They reported their preference for slow, medium, and fast tempo selections from each artist for three treadmill walking conditions at 40%, 60%, and 75% maximal heart rate reserve. A mixed-model 3 x 3 x 2 (Exercise Intensity x Music Tempo x Gender) analysis of variance was used to analyze the data. Results indicated there was no three-way interaction for music preference. There was, however, a significant (p < .05) two-way interaction for Exercise Intensity x Music Tempo (partial eta2 = .09) and a significant (p < .05) main effect for music tempo, with large differences evident between preference for medium versus slow tempo and fast versus slow tempo music at all exercise intensities (partial eta2 = .78). Participants reported a preference for both medium and fast tempo music at low and moderate exercise intensities and for fast tempo music at high intensity. Only partial support was found for the expected linear relationship between exercise intensity and music tempo preference.

  13. Simulation of heart rate variability model in a network

    NASA Astrophysics Data System (ADS)

    Cascaval, Radu C.; D'Apice, Ciro; D'Arienzo, Maria Pia

    2017-07-01

    We consider a 1-D model for the simulation of the blood flow in the cardiovascular system. As inflow condition we consider a model for the aortic valve. The opening and closing of the valve is dynamically determined by the pressure difference between the left ventricular and aortic pressures. At the outflow we impose a peripheral resistance model. To approximate the solution we use a numerical scheme based on the discontinuous Galerkin method. We also considering a variation in heart rate and terminal reflection coefficient due to monitoring of the pressure in the network.

  14. Heart rate variability biofeedback: how and why does it work?

    PubMed Central

    Lehrer, Paul M.; Gevirtz, Richard

    2014-01-01

    In recent years there has been substantial support for heart rate variability biofeedback (HRVB) as a treatment for a variety of disorders and for performance enhancement (Gevirtz, 2013). Since conditions as widely varied as asthma and depression seem to respond to this form of cardiorespiratory feedback training, the issue of possible mechanisms becomes more salient. The most supported possible mechanism is the strengthening of homeostasis in the baroreceptor (Vaschillo et al., 2002; Lehrer et al., 2003). Recently, the effect on the vagal afferent pathway to the frontal cortical areas has been proposed. In this article, we review these and other possible mechanisms that might explain the positive effects of HRVB. PMID:25101026

  15. Heart rate and estimated energy expenditure during ballroom dancing.

    PubMed

    Blanksby, B A; Reidy, P W

    1988-06-01

    Ten competitive ballroom dance couples performed simulated competitive sequences of Modern and Latin American dance. Heart rate was telemetered during the dance sequences and related to direct measures of oxygen uptake and heart rate obtained while walking on a treadmill. Linear regression was employed to estimate gross and net energy expenditures of the dance sequences. A multivariate analysis of variance with repeated measures on the dance factor was applied to the data to test for interaction and main effects on the sex and dance factors. Overall mean heart rate values for the Modern dance sequence were 170 beats.min-1 and 173 beats.min-1 for males and females respectively. During the Latin American sequence mean overall heart rate for males was 168 beats.min-1 and 177 beats.min-1 for females. Predicted mean gross values of oxygen consumption for the males were 42.8 +/- 5.7 ml.kg-1 min-1 and 42.8 +/- 6.9 ml.kg-1 min-1 for the Modern and Latin American sequences respectively. Corresponding gross estimates of oxygen consumption for the females were 34.7 +/- 3.8 ml.kg-1 min-1 and 36.1 +/- 4.1 ml.kg-1 min-1. Males were estimated to expand 54.1 +/- 8.1 kJ.min-1 of energy during the Modern sequence and 54.0 +/- 9.6 kJ.min-1 during the Latin American sequence, while predicted energy expenditure for females was 34.7 +/- 3.8 kJ.min-1 and 36.1 +/- 4.1 kJ.min-1 for Modern and Latin American dance respectively. The results suggested that both males and females were dancing at greater than 80% of their maximum oxygen consumption. A significant difference between males and females was observed for predicted gross and net values of oxygen consumption (in L.min-1 and ml.kg-1 min-1).

  16. Correlation of sleep EEG frequency bands and Heart Rate Variability.

    PubMed

    Abdullah, Haslaile; Holland, Gerard; Cosic, Irena; Cvetkovic, Dean

    2009-01-01

    Sleep apnoea is a sleep breathing disorder which causes changes in cardiac and neuronal activity and discontinuities in sleep pattern when observed via electrocardiogram (ECG) and electroencephalogram (EEG). This paper presents a pilot study result of assessing the correlation between EEG frequency bands and ECG Heart Rate Variability (HRV) in normal and sleep apnoea human clinical patients at different sleep stages. In sleep apnoea patients, the results have shown that EEG delta, sigma and beta bands exhibited a strong correlation with cardiac HRV parameters at different sleep stages.

  17. Heart rate turbulence predicts all-cause mortality and sudden death in congestive heart failure patients.

    PubMed

    Cygankiewicz, Iwona; Zareba, Wojciech; Vazquez, Rafael; Vallverdu, Montserrat; Gonzalez-Juanatey, Jose R; Valdes, Mariano; Almendral, Jesus; Cinca, Juan; Caminal, Pere; de Luna, Antoni Bayes

    2008-08-01

    Abnormal heart rate turbulence (HRT) has been documented as a strong predictor of total mortality and sudden death in postinfarction patients, but data in patients with congestive heart failure (CHF) are limited. The aim of this study was to evaluate the prognostic significance of HRT for predicting mortality in CHF patients in New York Heart Association (NYHA) class II-III. In 651 CHF patients with sinus rhythm enrolled into the MUSIC (Muerte Subita en Insuficiencia Cardiaca) study, the standard HRT parameters turbulence onset (TO) and slope (TS), as well as HRT categories, were assessed for predicting total mortality and sudden death. HRT was analyzable in 607 patients, mean age 63 years (434 male), 50% of ischemic etiology. During a median follow up of 44 months, 129 patients died, 52 from sudden death. Abnormal TS and HRT category 2 (HRT2) were independently associated with increased all-cause mortality (HR: 2.10, CI: 1.41 to 3.12, P <.001 and HR: 2.52, CI: 1.56 to 4.05, P <.001; respectively), sudden death (HR: 2.25, CI: 1.13 to 4.46, P = .021 for HRT2), and death due to heart failure progression (HR: 4.11, CI: 1.84 to 9.19, P <.001 for HRT2) after adjustment for clinical covariates in multivariate analysis. The prognostic value of TS for predicting total mortality was similar in various groups dichotomized by age, gender, NYHA class, left ventricular ejection fraction, and CHF etiology. TS was found to be predictive for total mortality only in patients with QRS > 120 ms. HRT is a potent risk predictor for both heart failure and arrhythmic death in patients with class II and III CHF.

  18. Heart rate reduction with ivabradine in patients with acute decompensated systolic heart failure.

    PubMed

    Sargento, Luis; Satendra, Milan; Longo, Susana; Lousada, Nuno; dos Reis, Roberto Palma

    2014-06-01

    In patients with acute decompensated systolic heart failure (ADSHF) high resting heart rate (HR) could be either a compensatory mechanism or contribute to worsening heart failure. The aim of this study was to evaluate, in patients with ADSHF and resting HR >70 bpm, the early (within 24 h) and late (at discharge) effects of oral administration of ivabradine on HR reduction. Ten consecutive patients with ADSHF, left ventricular ejection fraction <40 % and HR >70 bpm, without other acute conditions or inotropic therapy, began open-label treatment with oral ivabradine according to a pre-established Heart Failure Unit protocol. We obtained clinical and laboratory data at four periods: admission (T0), immediately before initiation of ivabradine (T2), 24 h after initiation of ivabradine (T3), and at discharge (T4). Ivabradine was administered in 60 % of the patients before the second day. HR decreased 10.7 ± 7.2 bpm at T3 (p < 0.001) and 16.3 ± 8.2 bpm at T4 (p = 0.002). The systolic blood pressure decreased at T3 (p = 0.012), returning to baseline values at T4. There was no change in diastolic and mean blood pressure. New York Heart Association (NYHA) class improvement by two levels was associated with lower HR at T4 (p = 0.033). HR and N-terminal pro-brain natriuretic peptide (Nt-ProBNP) at baseline correlated significantly [Spearman correlation coefficient (rs) = 0.789, p = 0.013]. Total Nt-ProBNP reduction correlated with the HR before (r = 0.762, p = 0.028) and after (T3: r = 0.647, p = 0.083; T4: r = 0.738, p = 0.037) ivabradine addition. In the present cohort of patients with ADSHF and HR >70 bpm, the selective reduction of HR with oral ivabradine was safe and efficient.

  19. Analysis of heart rate variability in the presence of ectopic beats using the heart timing signal.

    PubMed

    Mateo, Javier; Laguna, Pablo

    2003-03-01

    The time-domain signals representing the heart rate variability (HRV) in the presence of an ectopic beat exhibit a sharp transient at the position of the ectopic beat, which corrupts the signal, particularly the power spectral density (PSD) of the HRV. Consequently, there is a need for correction of this type of beat prior to any HRV analysis. This paper deals with the PSD estimation of the HRV by means of the heart timing (HT) signal when ectopic beats are present. These beat occurrence times are modeled from a generalized, continuous time integral pulse frequency modulation model and, from this point of view, a specific method for minimizing the effect of the presence of ectopic beats is presented to work together with the HT signal. By using both, a white noise driven autoregressive model of the HRV signal with artificially introduced ectopic beats and actual heart rate series including ectopic beats, the more usual methods of HRV spectral estimation are compared. Results of the PSD estimation error function of the number of ectopic beats are presented. These results demonstrate that the proposed method has one order of magnitude lower error than usual ectopic beats removal strategies in preserving PSD, thus, this strategy better recovers the original clinical indexes of interest.

  20. Estimating 'lost heart beats' rather than reductions in heart rate during the intubation of critically-ill children.

    PubMed

    Jones, Peter; Ovenden, Nick; Dauger, Stéphane; Peters, Mark J

    2014-01-01

    Reductions in heart rate occur frequently in children during critical care intubation and are currently considered the gold standard for haemodynamic instability. Our objective was to estimate loss of heart beats during intubation and compare this to reduction in heart rate alone whilst testing the impact of atropine pre-medication. Data were extracted from a prospective 2-year cohort study of intubation ECGs from critically ill children in PICU/Paediatric Transport. A three step algorithm was established to exclude variation in pre-intubation heart rate (using a 95%CI limit derived from pre-intubation heart rate variation of the children included), measure the heart rate over time and finally the estimate the numbers of lost beats. 333 intubations in children were eligible for inclusion of which 245 were available for analysis (74%). Intubations where the fall in heart rate was less than 50 bpm were accompanied almost exclusively by less than 25 lost beats (n = 175, median 0 [0-1]). When there was a reduction of >50 bpm there was a poor correlation with numbers of lost beats (n = 70, median 42 [15-83]). During intubation the median number of lost beats was 8 [1]-[32] when atropine was not used compared to 0 [0-0] when atropine was used (p<0.001). A reduction in heart rate during intubation of <50 bpm reliably predicted a minimal loss of beats. When the reduction in heart rate was >50 bpm the heart rate was poorly predictive of lost beats. A study looking at the relationship between lost beats and cardiac output needs to be performed. Atropine reduces both fall in heart rate and loss of beats. Similar area-under-the-curve methodology may be useful for estimating risk when biological parameters deviate outside normal range.

  1. Estimating ‘Lost Heart Beats’ Rather than Reductions in Heart Rate during the Intubation of Critically-Ill Children

    PubMed Central

    Jones, Peter; Ovenden, Nick; Dauger, Stéphane; Peters, Mark J.

    2014-01-01

    Purpose Reductions in heart rate occur frequently in children during critical care intubation and are currently considered the gold standard for haemodynamic instability. Our objective was to estimate loss of heart beats during intubation and compare this to reduction in heart rate alone whilst testing the impact of atropine pre-medication. Methods Data were extracted from a prospective 2-year cohort study of intubation ECGs from critically ill children in PICU/Paediatric Transport. A three step algorithm was established to exclude variation in pre-intubation heart rate (using a 95%CI limit derived from pre-intubation heart rate variation of the children included), measure the heart rate over time and finally the estimate the numbers of lost beats. Results 333 intubations in children were eligible for inclusion of which 245 were available for analysis (74%). Intubations where the fall in heart rate was less than 50 bpm were accompanied almost exclusively by less than 25 lost beats (n = 175, median 0 [0–1]). When there was a reduction of >50 bpm there was a poor correlation with numbers of lost beats (n = 70, median 42 [15–83]). During intubation the median number of lost beats was 8 [1]–[32] when atropine was not used compared to 0 [0–0] when atropine was used (p<0.001). Conclusions A reduction in heart rate during intubation of <50 bpm reliably predicted a minimal loss of beats. When the reduction in heart rate was >50 bpm the heart rate was poorly predictive of lost beats. A study looking at the relationship between lost beats and cardiac output needs to be performed. Atropine reduces both fall in heart rate and loss of beats. Similar area-under-the-curve methodology may be useful for estimating risk when biological parameters deviate outside normal range. PMID:24503645

  2. Dynamic analysis of heart rate may predict subsequent ventricular tachycardia after myocardial infarction

    NASA Technical Reports Server (NTRS)

    Makikallio, T. H.; Seppanen, T.; Airaksinen, K. E.; Koistinen, J.; Tulppo, M. P.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

    1997-01-01

    Dynamics analysis of RR interval behavior and traditional measures of heart rate variability were compared between postinfarction patients with and without vulnerability to ventricular tachyarrhythmias in a case-control study. Short-term fractal correlation of heart rate dynamics was better than traditional measures of heart rate variability in differentiating patients with and without life-threatening arrhythmias.

  3. Heart Rate and Lactate Levels during Weight-Training Exercise in Trained and Untrained Men.

    ERIC Educational Resources Information Center

    Stone, Michael H.; And Others

    1987-01-01

    A study of effects of squatting exercise on heart rate and blood lactate levels in trained and untrained males indicated that trained subjects performed more work and had higher heart rates and lactate levels at exhaustion untrained subjects, though heart rate and lactate levels were lower for trained subjects at a given bar mass or submaximal…

  4. The Relationship between Heart Rate Reserve and Oxygen Uptake Reserve in Children and Adolescents

    ERIC Educational Resources Information Center

    Hui, Stanley Sai-chuen; Chan, Janus Wan-sze

    2006-01-01

    The purpose of the present study was to examine the relationship between oxygen uptake (VO[subscript 2]) and heart rate (HR) responses during rest and exercise in Chinese children and youth and to evaluate the relationships between maximal heart rate (%HRmax), heart rate reserve (%HRR), peak oxygen uptake (%VO[subscript 2]peak), and oxygen uptake…

  5. Comparison of Traditional and Alternative Fitness Teaching Formats on Heart Rate Intensity and Perceived Enjoyment.

    ERIC Educational Resources Information Center

    Ha, Amy Sau-ching; Heung-Sang Wong, Stephen

    2002-01-01

    Compared a traditional and an alternative (skill-fitness- music) fitness teaching format to determine whether there would be differences on Hong Kong middle school students' heart rate intensity and perceived enjoyment. Data from heart rate monitors and student surveys indicated that the two formats did not produce differences in heart rates.…

  6. Making the Most of the "Daphnia" Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine

    ERIC Educational Resources Information Center

    Corotto, Frank; Ceballos, Darrel; Lee, Adam; Vinson, Lindsey

    2010-01-01

    Students commonly test the effects of chemical agents on the heart rate of the crustacean "Daphnia" magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in "Daphnia." Ethanol at 5% and 10% (v/v) reduced mean heart rate to…

  7. Heart Rates of High School Physical Education Students during Team Sports, Individual Sports, and Fitness Activities

    ERIC Educational Resources Information Center

    Laurson, Kelly R.; Brown, Dale D.; Cullen, Robert W.; Dennis, Karen K.

    2008-01-01

    This study examined how activity type influenced heart rates and time spent in target heart rate zones of high school students participating in physical education classes. Significantly higher average heart rates existed for fitness (142 plus or minus 24 beats per minute [bpm]) compared to team (118 plus or minus 24 bpm) or individual (114 plus or…

  8. Dynamic analysis of heart rate may predict subsequent ventricular tachycardia after myocardial infarction

    NASA Technical Reports Server (NTRS)

    Makikallio, T. H.; Seppanen, T.; Airaksinen, K. E.; Koistinen, J.; Tulppo, M. P.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

    1997-01-01

    Dynamics analysis of RR interval behavior and traditional measures of heart rate variability were compared between postinfarction patients with and without vulnerability to ventricular tachyarrhythmias in a case-control study. Short-term fractal correlation of heart rate dynamics was better than traditional measures of heart rate variability in differentiating patients with and without life-threatening arrhythmias.

  9. The Relationship between Heart Rate Reserve and Oxygen Uptake Reserve in Children and Adolescents

    ERIC Educational Resources Information Center

    Hui, Stanley Sai-chuen; Chan, Janus Wan-sze

    2006-01-01

    The purpose of the present study was to examine the relationship between oxygen uptake (VO[subscript 2]) and heart rate (HR) responses during rest and exercise in Chinese children and youth and to evaluate the relationships between maximal heart rate (%HRmax), heart rate reserve (%HRR), peak oxygen uptake (%VO[subscript 2]peak), and oxygen uptake…

  10. Heart Rate and Lactate Levels during Weight-Training Exercise in Trained and Untrained Men.

    ERIC Educational Resources Information Center

    Stone, Michael H.; And Others

    1987-01-01

    A study of effects of squatting exercise on heart rate and blood lactate levels in trained and untrained males indicated that trained subjects performed more work and had higher heart rates and lactate levels at exhaustion untrained subjects, though heart rate and lactate levels were lower for trained subjects at a given bar mass or submaximal…

  11. Making the Most of the "Daphnia" Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine

    ERIC Educational Resources Information Center

    Corotto, Frank; Ceballos, Darrel; Lee, Adam; Vinson, Lindsey

    2010-01-01

    Students commonly test the effects of chemical agents on the heart rate of the crustacean "Daphnia" magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in "Daphnia." Ethanol at 5% and 10% (v/v) reduced mean heart rate to…

  12. Heart Rates of High School Physical Education Students during Team Sports, Individual Sports, and Fitness Activities

    ERIC Educational Resources Information Center

    Laurson, Kelly R.; Brown, Dale D.; Cullen, Robert W.; Dennis, Karen K.

    2008-01-01

    This study examined how activity type influenced heart rates and time spent in target heart rate zones of high school students participating in physical education classes. Significantly higher average heart rates existed for fitness (142 plus or minus 24 beats per minute [bpm]) compared to team (118 plus or minus 24 bpm) or individual (114 plus or…

  13. Deep breathing heart rate variability is associated with inspiratory muscle weakness in chronic heart failure.

    PubMed

    Reis, Michel Silva; Arena, Ross; Archiza, Bruno; de Toledo, Carlos Fischer; Catai, Aparecida Maria; Borghi-Silva, Audrey

    2014-03-01

    There is a synchronism between the respiratory and cardiac cycles. However, the relationship of inspiratory muscle weakness in chronic heart failure (CHF) on cardiac autonomic modulation is unknown. The purpose of the present investigation was to evaluate the impact of inspiratory muscle strength on the magnitude of respiratory sinus arrhythmia. Ten CHF (62 ± 7 years--left ventricle eject fraction of 40 ± 5% and New York Heart Association class I-III) and nine matched-age healthy volunteers (64 ± 5 years) participated in this study. Heart rate variability (HRV) was obtained at rest and during deep breathing manoeuvre (DB-M) by electrocardiograph. CHF patients demonstrated impaired cardiac autonomic modulation at rest and during DB-M when compared with healthy subjects (p < 0.05). Moreover, significant and positive correlations between maximal inspiratory pressure and inspiratory-expiratory differences (r = 0.79), expiratory/inspiratory ratio (r = 0.83), root mean square of the successive differences (r = 0.77), standard deviation of NN intervals (r = 0.77), low frequency (r = 0.77), and high frequency (r = 0.70) were found during DB-M. At rest, significant correlations were found also. Patients with CHF presented impaired cardiac autonomic modulation at rest. In addition, cardiac autonomic control of heart rate was associated with inspiratory muscle weakness in CHF. Based on this evidence, recommendations for future research applications of respiratory muscle training can bring to light a potentially valuable target for rehabilitation. Copyright © 2013 John Wiley & Sons, Ltd.

  14. Effects of Vibration and G-Loading on Heart Rate, Breathing Rate, and Response Time

    NASA Technical Reports Server (NTRS)

    Godinez, Angelica; Ayzenberg, Ruthie; Liston, Dorian B.; Stone, Leland S.

    2013-01-01

    Aerospace and applied environments commonly expose pilots and astronauts to G-loading and vibration, alone and in combination, with well-known sensorimotor (Cohen, 1970) and performance consequences (Adelstein et al., 2008). Physiological variables such as heart rate (HR) and breathing rate (BR) have been shown to increase with G-loading (Yajima et al., 1994) and vibration (e.g. Guignard, 1965, 1985) alone. To examine the effects of G-loading and vibration, alone and in combination, we measured heart rate and breathing rate under aerospace-relevant conditions (G-loads of 1 Gx and 3.8 Gx; vibration of 0.5 gx at 8, 12, and 16 Hz).

  15. Mercury Exposure and Heart Rate Variability: A Systematic Review

    PubMed Central

    Gribble, Matthew O.; Cheng, Alan; Berger, Ronald D.; Rosman, Lori; Guallar, Eliseo

    2015-01-01

    Background Mercury affects the nervous system and has been implicated in altering heart rhythm and function. We sought to better define its role in modulating heart rate variability, a well-known marker of cardiac autonomic function. Design Systematic review. Methods We searched PubMed, Embase, TOXLINE and DART databases without language restriction. We report findings as a qualitative systematic review because heterogeneity in study design and assessment of exposures and outcomes across studies, as well as other methodological limitations of the literature, precluded a quantitative meta-analysis. Results We identified 12 studies of mercury exposure and heart rate variability in human populations (10 studies involving primarily environmental methylmercury exposure and two studies involving occupational exposure to inorganic mercury) conducted in Japan, the Faroe Islands, Canada, Korea, French Polynesia, Finland and Egypt. The association of prenatal mercury exposure with lower high-frequency band scores (thought to reflect parasympathetic activity) in several studies, in particular the inverse association of cord blood mercury levels with the coefficient of variation of the R-R intervals and with low frequency and high frequency bands at 14 years of age in the Faroe Islands birth cohort study, suggests that early mercury exposure could have a long-lasting effect on cardiac parasympathetic activity. Studies with later environmental exposures to mercury in children or in adults were heterogeneous and did not show consistent associations. Conclusions The evidence was too limited to draw firm causal inferences. Additional research is needed to elucidate the effects of mercury on cardiac autonomic function, particularly as early-life exposures might have lasting impacts on cardiac parasympathetic function. PMID:26231507

  16. Effects of atropine and pirenzepine on heart rate turbulence.

    PubMed

    Vukajlovic, Dejan D; Guettler, Norbert; Miric, Milutin; Pitschner, Heinz Friedrich

    2006-01-01

    It has been shown that mortality risk in patients after myocardial infarction could be estimated by heart rate turbulence (HRT), a short-term change in heart rate after ventricular premature beat (VPB), presumably caused by baroreceptor mechanism. We sought to determine whether pharmacological blockade with atropine, or augmentation of vagal tone with pirenzepine given in small doses would influence HRT. In 30 patients with normal echocardiogram, and without signs or symptoms of coronary artery disease, after electrophysiologic examination or radiofrequency ablation for supraventricular arrhythmias was completed, turbulence onset (TO) and turbulence slope (TS) in basal state, after 1.3 mg IV pirenzepine and finally, after atropine in dose of 0.04 mg/kg of body weight were compared. As assessed by Friedman ANOVA test both pirenzepine and atropine caused a significant change in both TO (P < 0.01) and TS (P < 0.01). The mean basal TO of -3.6 +/- 2.9%, changed after pirenzepine to -5.99 +/- 5.6% (P < 0.01), and after atropine it changed to -3.3 +/- 18.1% (P < 0.01). The mean basal TS of 18.6 +/- 10.1 ms/R-R interval increased after pirenzepine to 26.8 +/- 19.9 ms/R-R interval (P < 0.05), and decreased after atropine to 1.2 +/- 0.8 ms/R-R interval (P < 0.01). Mean cycle length increased after pirenzepine from 706.8 +/- 106.8 to 830 +/- 151.9 ms (P < 0.01), and decreased after atropine to 454.2 +/- 58.1 ms (P < 0.01). A conclusion could be drawn that vagomymetic manipulation with intravenous pirenzepine increases HRT; vagal blockade with atropine decreases HRT. This finding suggests that a normal vagal innervation of heart is a prerequisite for the phenomenon of HRT.

  17. Heart rate variability changes in physicians working on night call.

    PubMed

    Malmberg, Birgitta; Persson, Roger; Flisberg, Per; Ørbaek, Palle

    2011-03-01

    Adverse effects by night-call duty have become an important occupational health issue. The aim of this study was to investigate whether the heart rate variability (HRV) differed during recovery from day work and night-call duty between distinct physician specialities. We studied the impact of a 16-h night-call duty on autonomic balance, measured by HRV, among two physician groups differing with respect to having to deal with life-threatening conditions while on call. Nineteen anaesthesiologists (ANEST) and 16 paediatricians and ear, nose and throat surgeons (PENT) were monitored by ambulatory digital Holter electrocardiogram (ECG). Heart rate variability was analysed between 21:00 and 22:00 after an ordinary workday, on night call and in the evening post-call. Absolute and normalized high-frequency power (HF, HFnu) were the main outcome variables, expressing parasympathetic influence on the heart. ANEST had lower HF power than PENT while on night call and post-daytime work (p < 0.05), but not at post-night call. In the whole group of physicians, HFnu was lower on call and post-daytime work compared with post-night-call duty (p < 0.05). The physiological recovery after night duty seemed sufficient in terms of HRV patterns for HFnu, reflecting autonomic balance and did not differ between specialities. However, the less dynamic HRV after daytime work and during night-call duty in the ANEST group may indicate a higher physiological stress level. These results may contribute to the improvement of night-call schedules within the health care sector.

  18. Heart-rate variability and precompetitive anxiety in swimmers.

    PubMed

    Cervantes Blásquez, Julio César; Rodas Font, Gil; Capdevila Ortís, Lluís

    2009-11-01

    The aim of this study was to test the utility of heart-rate variability (HRV) analyses as a noninvasive means of quantifying cardiac autonomic regulation during precompetitive anxiety situations in swimmers. Psychophysiological state evaluation of 10 volunteer swimmers (6 women and 4 men) was obtained by comparing baseline training condition (TC) with competition condition (CC). Self-evaluation of precompetitive somatic anxiety measured by CSAI-2 showed significant increase from the TC to CC. Analysis showed that during higher precompetitive anxiety level, a significant reduction in the timing (RMSSD), frequency (HFms2 and HFnu) and Poincaré plot (SD1) of heart-rate variability was observed, and a significant increase in the low frequency to high frequency ratio (LF/HF %). The results indicate a shift towards sympathetic predominance as a result of parasympathetic withdrawal. Our results provide an HRV analysis in a valid, useful and non-invasive way to evaluate the change of sympathovagal balance in presence of precompetitive stress.

  19. Abnormal intermittency of heart rate in patients with neurocardiogenic syncope

    NASA Astrophysics Data System (ADS)

    Yum, Myung-Kul; Kim, Kyung-Sik; Kim, June-Soo

    2002-03-01

    Introduction: We aim to test our hypothesis that, during daily activity, though not as prominent as during HUT test, the patients may show different degree of intermittency in heart rates compared to healthy persons. METHOD AND RESULTS: Thirty patients with neurocardiogenic syncope who showed a positive HUT test and thirty healthy controls without history of syncope were included. Their twenty-four hour ambulatory electrocardiograms were digitized and RR interval (RRI) data of six-hour interval were analyzed. To quantify the intermittency (C1) behavior, The intermittency analysis was performed using Mexican hat wavelet. For the syncope group, the values of C1 were significantly higher at 6AM-6PM and lower at 6AM-midnight, respectively. However, the values were not different at midnight-6AM. The significant night-day circadian change shown in the control group was lost in C1. CONCLUSION: When compared to healthy control, the patients with neurocardiogenic syncope shows increased intermittency of heart rates in daytime during daily activity, and abnormal circadian rhythms of the index. These new findings may be useful for investigating the pathophysiology of neurocardiogenic syncope and early identification of the patients.

  20. Motion-compensated non-contact detection of heart rate

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Liu, Ming; Dong, Liquan; Zhao, Yuejin; Liu, Xiaohua

    2015-12-01

    A new non-contact heart rate detection method based on the dual-wavelength technique is proposed and demonstrated experimentally. It is a well-known fact that the differences in the circuits of two detection modules result in different responses of two modules for motion artifacts. This poses a great challenge to compensate the motion artifacts during measurements. In order to circumvent this problem, we have proposed the amplitude spectrum and phase spectrum adaptive filter. Comparing with the time-domain adaptive filter and independent component analysis, the amplitude spectrum and phase spectrum adaptive filter can suppress the interference caused by the two circuit differences and effectively compensate the motion artifacts. To make the device is much compact and portable, a photoelectric probe is designed. The measurement distance is from several centimeters up to several meters. Moreover, the data obtained by using this non-contact detection system is compared with those of the conventional finger blood volume pulse (BVP) sensor by simultaneously measuring the heart rate of the subject. The data obtained from the proposed non-contact system are consistent and comparable with that of the BVP sensor.

  1. Robust estimation of fetal heart rate from US Doppler signals

    NASA Astrophysics Data System (ADS)

    Voicu, Iulian; Girault, Jean-Marc; Roussel, Catherine; Decock, Aliette; Kouame, Denis

    2010-01-01

    Introduction: In utero, Monitoring of fetal wellbeing or suffering is today an open challenge, due to the high number of clinical parameters to be considered. An automatic monitoring of fetal activity, dedicated for quantifying fetal wellbeing, becomes necessary. For this purpose and in a view to supply an alternative for the Manning test, we used an ultrasound multitransducer multigate Doppler system. One important issue (and first step in our investigation) is the accurate estimation of fetal heart rate (FHR). An estimation of the FHR is obtained by evaluating the autocorrelation function of the Doppler signals for ills and healthiness foetus. However, this estimator is not enough robust since about 20% of FHR are not detected in comparison to a reference system. These non detections are principally due to the fact that the Doppler signal generated by the fetal moving is strongly disturbed by the presence of others several Doppler sources (mother' s moving, pseudo breathing, etc.). By modifying the existing method (autocorrelation method) and by proposing new time and frequency estimators used in the audio' s domain, we reduce to 5% the probability of non-detection of the fetal heart rate. These results are really encouraging and they enable us to plan the use of automatic classification techniques in order to discriminate between healthy and in suffering foetus.

  2. Predicted maximal heart rate for upper body exercise testing.

    PubMed

    Hill, M; Talbot, C; Price, M

    2016-03-01

    Age-predicted maximal heart rate (HRMAX ) equations are commonly used for the purpose of prescribing exercise regimens, as criteria for achieving maximal exertion and for diagnostic exercise testing. Despite the growing popularity of upper body exercise in both healthy and clinical settings, no recommendations are available for exercise modes using the smaller upper body muscle mass. The purpose of this study was to determine how well commonly used age-adjusted prediction equations for HRMAX estimate actual HRMAX for upper body exercise in healthy young and older adults. A total of 30 young (age: 20 ± 2 years, height: 171·9 ± 32·8 cm, mass: 77·7 ± 12·6 kg) and 20 elderly adults (age: 66 ± 6 years, height: 162 ± 8·1 cm, mass: 65·3 ± 12·3 kg) undertook maximal incremental exercise tests on a conventional arm crank ergometer. Age-adjusted maximal heart rate was calculated using prediction equations based on leg exercise and compared with measured HRMAX data for the arms. Maximal HR for arm exercise was significantly overpredicted compared with age-adjusted prediction equations in both young and older adults. Subtracting 10-20 beats min(-1) from conventional prediction equations provides a reasonable estimate of HRMAX for upper body exercise in healthy older and younger adults. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  3. Exercise heart rates in patients with hypertrophic cardiomyopathy.

    PubMed

    Luo, Hong-Chang; Dimaano, Veronica L; Kembro, Jackelyn M; Hilser, Alex; Hurtado-de-Mendoza, David; Pozios, Iraklis; Tomas, Miguel S; Yalcin, Hulya; Dolores-Cerna, Ketty; Mormontoy, Wilfredo; Aon, Miguel A; Cameron, Duke; Bluemke, David A; Stewart, Kerry J; Russell, Stuart D; Cordova, Jorge G; Abraham, Theodore P; Abraham, M Roselle

    2015-04-15

    The exercise heart rate (HR) profile and its relation to cardiac function and arrhythmias were investigated in patients with hypertrophic cardiomyopathy (HC). Chronotropic response (CR) and heart rate recovery (HRR) were computed during and after treadmill exercise testing in 273 patients with HC and 95 age-matched healthy controls. Patients with HC had higher prevalence of chronotropic incompetence and lower HRR1-5min compared with controls. Exercise capacity, diastolic function (assessed by E/e') and left atrial volume index were associated with HRR1min and CR in HC. Septal myectomy was associated with reduction in chronotropic incompetence but did not affect HRR1min. In conclusion, impaired CR and HRR1min are associated with advanced disease and do not appear to be independent clinical markers indicating high-risk status in HC. Improving CR by titrating doses of negative chronotropic agents, myectomy, and atrial pacing may be useful to increase exercise capacity in patients with HC. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Human heart rate variability relation is unchanged during motion sickness

    NASA Technical Reports Server (NTRS)

    Mullen, T. J.; Berger, R. D.; Oman, C. M.; Cohen, R. J.

    1998-01-01

    In a study of 18 human subjects, we applied a new technique, estimation of the transfer function between instantaneous lung volume (ILV) and instantaneous heart rate (HR), to assess autonomic activity during motion sickness. Two control recordings of ILV and electrocardiogram (ECG) were made prior to the development of motion sickness. During the first, subjects were seated motionless, and during the second they were seated rotating sinusoidally about an earth vertical axis. Subjects then wore prism goggles that reverse the left-right visual field and performed manual tasks until they developed moderate motion sickness. Finally, ILV and ECG were recorded while subjects maintained a relatively constant level of sickness by intermittent eye closure during rotation with the goggles. Based on analyses of ILV to HR transfer functions from the three conditions, we were unable to demonstrate a change in autonomic control of heart rate due to rotation alone or due to motion sickness. These findings do not support the notion that moderate motion sickness is manifested as a generalized autonomic response.

  5. Human heart rate variability relation is unchanged during motion sickness

    NASA Technical Reports Server (NTRS)

    Mullen, T. J.; Berger, R. D.; Oman, C. M.; Cohen, R. J.

    1998-01-01

    In a study of 18 human subjects, we applied a new technique, estimation of the transfer function between instantaneous lung volume (ILV) and instantaneous heart rate (HR), to assess autonomic activity during motion sickness. Two control recordings of ILV and electrocardiogram (ECG) were made prior to the development of motion sickness. During the first, subjects were seated motionless, and during the second they were seated rotating sinusoidally about an earth vertical axis. Subjects then wore prism goggles that reverse the left-right visual field and performed manual tasks until they developed moderate motion sickness. Finally, ILV and ECG were recorded while subjects maintained a relatively constant level of sickness by intermittent eye closure during rotation with the goggles. Based on analyses of ILV to HR transfer functions from the three conditions, we were unable to demonstrate a change in autonomic control of heart rate due to rotation alone or due to motion sickness. These findings do not support the notion that moderate motion sickness is manifested as a generalized autonomic response.

  6. Heart rate variability in children with type 1 diabetes mellitus

    PubMed Central

    Gardim, Camila Balsamo; de Oliveira, Bruno Affonso P.; Bernardo, Aline Fernanda B.; Gomes, Rayana Loch; Pacagnelli, Francis Lopes; Lorençoni, Roselene Modolo R.; Vanderlei, Luiz Carlos M.

    2014-01-01

    OBJECTIVE: To gather current information about the effects of type 1 diabetes mellitus on children's cardiac autonomic behavior. DATA SOURCES: The search of articles was conducted on PubMed, Ibecs, Medline, Cochrane, Lilacs, SciELO and PEDro databases using the MeSH terms: "autonomic nervous system", "diabetes mellitus", "child", "type 1 diabetes mellitus", "sympathetic nervous system" and "parasympathetic nervous system", and their respective versions in Portuguese (DeCS). Articles published from January 2003 to February 2013 that enrolled children with 9-12 years old with type 1 diabetes mellitus were included in the review. DATA SYNTHESIS: The electronic search resulted in four articles that approached the heart rate variability in children with type 1 diabetes mellitus, showing that, in general, these children present decreased global heart rate variability and vagal activity. The practice of physical activity promoted benefits for these individuals. CONCLUSIONS: Children with type 1 diabetes mellitus present changes on autonomic modulation, indicating the need for early attention to avoid future complications in this group. PMID:25119762

  7. Determinants for Heart Rate Variability in a Normal Korean Population

    PubMed Central

    Kim, Gyung-Mee

    2011-01-01

    This study examined the normal ranges and the determinants for various parameters of the short-term heart rate variability (HRV) measurements in a large Korean sample of healthy people. HRV measurements were obtained in 2,748 healthy men and 735 healthy women 18-65 yr of age. The mean total power (TP), low frequency (LF), high frequency (HF), and LF/HF ratio were 1,358.9 ± 1,840.8 ms2, 417.3 ± 807.6 ms2, 254.1 ± 414.1 ms2, and 2.4 ± 20.9 ms2 in the frequency-domain spectral analysis. The mean standard deviation of the normal-to-normal (NN) interval (SDNN) and the square root of the mean squared differences of successive NN intervals (RMSSD) were 39.6 ± 22.1 ms and 29.7 ± 18.1 ms in the time-domain analysis. The female subjects had significantly higher SDNN, RMSSD, and HF values than the male subjects. After controlling for age, there was no statistically significant difference in the SDNN. Quantile regression analysis showed that age and mean heart rate had a significant impact on short-term HRV measurement. Given that both clinicians and researchers are increasingly relying on short-term HRV assessment in measuring stress, our work suggests that age and gender should be considered as independent determinants for HRV. PMID:22022180

  8. Estimation of Measurement Characteristics of Ultrasound Fetal Heart Rate Monitor

    NASA Astrophysics Data System (ADS)

    Noguchi, Yasuaki; Mamune, Hideyuki; Sugimoto, Suguru; Yoshida, Atsushi; Sasa, Hidenori; Kobayashi, Hisaaki; Kobayashi, Mitsunao

    1995-05-01

    Ultrasound fetal heart rate monitoring is very useful to determine the status of the fetus because it is noninvasive. In order to ensure the accuracy of the fetal heart rate (FHR) obtained from the ultrasound Doppler data, we measure the fetal electrocardiogram (ECG) directly and obtain the Doppler data simultaneously. The FHR differences of the Doppler data from the direct ECG data are concentrated at 0 bpm (beats per minute), and are practically symmetrical. The distribution is found to be very close to the Student's t distribution by the test of goodness of fit with the chi-square test. The spectral density of the FHR differences shows the white noise spectrum without any dominant peaks. Furthermore, the f-n (n>1) fluctuation is observed both with the ultrasound Doppler FHR and with the direct ECG FHR. Thus, it is confirmed that the FHR observation and observation of the f-n (n>1) fluctuation using the ultrasound Doppler FHR are as useful as the direct ECG.

  9. Simulation of fetal heart rate variability with a mathematical model.

    PubMed

    Jongen, Germaine J L M; van der Hout-van der Jagt, M Beatrijs; Oei, S Guid; van de Vosse, Frans N; Bovendeerd, Peter H M

    2017-04-01

    In the clinic, the cardiotocogram (CTG), the combined registration of fetal heart rate (FHR) and uterine contractions, is used to predict fetal well-being. Amongst others, fetal heart rate variability (FHRV) is an important indicator of fetal distress. In this study we add FHRV to our previously developed CTG simulation model, in order to improve its use as a research and educational tool. We implemented three sources of variability by applying either 1/f or white noise to the peripheral vascular resistance, baroreceptor output, or efferent vagal signal. Simulated FHR tracings were evaluated by visual inspection and spectral analysis. All power spectra showed a 1/f character, irrespective of noise type and source. The clinically observed peak near 0.1 Hz was only obtained by applying white noise to the different sources of variability. Similar power spectra were found when peripheral vascular resistance or baroreceptor output was used as source of variability. Sympathetic control predominantly influenced the low frequency power, while vagal control influenced both low and high frequency power. In contrast to clinical data, model results did not show an increase of FHRV during FHR decelerations. Still, addition of FHRV improves the applicability of the model as an educational and research tool.

  10. Facets of psychopathy, heart rate variability and cognitive function.

    PubMed

    Hansen, Anita Lill; Johnsen, Bjørn Helge; Thornton, David; Waage, Leif; Thayer, Julian F

    2007-10-01

    The aim of the present study was to investigate whether the four facets of Hare's Psychopathy Checklist-Revised (PCL-R; Hare, 1991; Bolt, Hare, Vitale, & Newman, 2004) were related to physiological and cognitive mechanisms. Fifty-three male prisoners participated in this study. Physiological responses were measured as heart rate variability (HRV) and heart rate (HR). Cognitive functions were measured using a continuous performance test (CPT; California Computerized Assessment Package, Abbreviated version) and a working memory test (WMT); based on Baddeley & Hitch (1974). The regression analysis of the HRV revealed that the interpersonal facet explained most of the variance during baseline (28%), CPT (16%), and WMT (12%). This was also true for the HR data during baseline (28%), CPT (20%), WMT (10%), and recovery (13%). The antisocial facet explained 10% of the variance only during baseline. Subjects scoring high compared to low on the interpersonal facet also showed better cognitive functioning. The study suggests that the different facets were differently associated with both physiological and cognitive functions.

  11. TRPA1 mediates changes in heart rate variability and cardiac ...

    EPA Pesticide Factsheets

    Short-term exposure to ambient air pollution is linked with adverse cardiovascular effects. While previous research focused primarily on particulate matter-induced responses, gaseous air pollutants also contribute to cause short-term cardiovascular effects. Mechanisms underlying such effects have not been adequately described; however, the immediate nature of the response suggests involvement of irritant neural activation and downstream autonomic dysfunction. Thus, this study examines the role of TRPA1, an irritant sensory receptor found in the airways, in the cardiac response of mice to acrolein and ozone. Conscious unrestrained wild-type C57BL/6 (WT) and TRPA1 knockout (KO) mice implanted with radiotelemeters were exposed once to 3ppm acrolein, 0.3ppm ozone, or filtered air. Heart rate (HR) and electrocardiogram (ECG) were recorded continuously before, during and after exposure. Analysis of ECG morphology, incidence of arrhythmia and heart rate variability (HRV) were performed. Cardiac mechanical function was assessed using a Langendorff perfusion preparation 24h post-exposure. Acrolein exposure increased HRV independent of HR, as well as incidence of arrhythmia. Acrolein also increased left ventricular developed pressure in WT mice at 24h post-exposure. Ozone did not produce any changes in cardiac function. Neither gas produced ECG effects, changes in HRV, arrhythmogenesis, or mechanical function in KO mice. These data demonstrate that a single exposure to ac

  12. Intra-task variability of trunk coordination during a rate-controlled bipedal dance jump.

    PubMed

    Smith, Jo Armour; Siemienski, Adam; Popovich, John M; Kulig, Kornelia

    2012-01-01

    In this study, we investigated trunk coordination during rate-controlled bipedal vertical dance jumps. The aims of the study were to investigate the pattern of coordination and the magnitude of coordination variability within jump phases and relative to phase-defining events during the jump. Lumbar and thoracic kinematics were collected from seven dancers during a series of jumps at 95 beats per minute. The vector coding technique was used to quantify the pattern and variability of trunk coordination. Coordination was predominantly anti-phase during propulsion and landing. Mean coordination variability peaked just before the landing phase and at the transition from landing to propulsion phases, and was lowest during the propulsion phase just before toe-off. The results indicate that peaks in variability could be explained by task and phase-specific biomechanical demands.

  13. Resting Heart Rate as Predictor for Left Ventricular Dysfunction and Heart Failure: The Multi-Ethnic Study of Atherosclerosis

    PubMed Central

    Opdahl, Anders; Venkatesh, Bharath Ambale; Fernandes, Veronica R. S.; Wu, Colin O.; Nasir, Khurram; Choi, Eui-Young; Almeida, Andre L. C.; Rosen, Boaz; Carvalho, Benilton; Edvardsen, Thor; Bluemke, David A.; Lima, Joao A. C.

    2014-01-01

    OBJECTIVE To investigate the relationship between baseline resting heart rate and incidence of heart failure (HF) and global and regional left ventricular (LV) dysfunction. BACKGROUND The association of resting heart rate to HF and LV function is not well described in an asymptomatic multi-ethnic population. METHODS Participants in the Multi-Ethnic Study of Atherosclerosis had resting heart rate measured at inclusion. Incident HF was registered (n=176) during follow-up (median 7 years) in those who underwent cardiac MRI (n=5000). Changes in ejection fraction (ΔEF) and peak circumferential strain (Δεcc) were measured as markers of developing global and regional LV dysfunction in 1056 participants imaged at baseline and 5 years later. Time to HF (Cox model) and Δεcc and ΔEF (multiple linear regression models) were adjusted for demographics, traditional cardiovascular risk factors, calcium score, LV end-diastolic volume and mass in addition to resting heart rate. RESULTS Cox analysis demonstrated that for 1 bpm increase in resting heart rate there was a 4% greater adjusted relative risk for incident HF (Hazard Ratio: 1.04 (1.02, 1.06 (95% CI); P<0.001). Adjusted multiple regression models demonstrated that resting heart rate was positively associated with deteriorating εcc and decrease in EF, even in analyses when all coronary heart disease events were excluded from the model. CONCLUSION Elevated resting heart rate is associated with increased risk for incident HF in asymptomatic participants in MESA. Higher heart rate is related to development of regional and global LV dysfunction independent of subclinical atherosclerosis and coronary heart disease. PMID:24412444

  14. Resting heart rate as predictor for left ventricular dysfunction and heart failure: MESA (Multi-Ethnic Study of Atherosclerosis).

    PubMed

    Opdahl, Anders; Ambale Venkatesh, Bharath; Fernandes, Veronica R S; Wu, Colin O; Nasir, Khurram; Choi, Eui-Young; Almeida, Andre L C; Rosen, Boaz; Carvalho, Benilton; Edvardsen, Thor; Bluemke, David A; Lima, João A C

    2014-04-01

    The objective of this study was to investigate the relationship between baseline resting heart rate and incidence of heart failure (HF) and global and regional left ventricular (LV) dysfunction. The association of resting heart rate to HF and LV function has not been well described in an asymptomatic multi-ethnic population. Resting heart rate was measured in participants in the MESA (Multi-Ethnic Study of Atherosclerosis) trial at inclusion. Incident HF was registered (n = 176) during follow-up (median 7 years) in those who underwent cardiac magnetic resonance imaging (n = 5,000). Changes in ejection fraction (ΔEF) and peak circumferential strain (Δεcc) were measured as markers of developing global and regional LV dysfunction in 1,056 participants imaged at baseline and 5 years later. Time to HF (Cox model) and Δεcc and ΔEF (multiple linear regression models) were adjusted for demographics, traditional cardiovascular risk factors, calcium score, LV end-diastolic volume, and mass in addition to resting heart rate. Cox analysis demonstrated that for 1 beat/min increase in resting heart rate, there was a 4% greater adjusted relative risk for incident HF (hazard ratio: 1.04; 95% CI: 1.02 to 1.06; p < 0.001). Adjusted multiple regression models demonstrated that resting heart rate was positively associated with deteriorating εcc and decrease in EF, even when all coronary heart disease events were excluded from the model. Elevated resting heart rate was associated with increased risk for incident HF in asymptomatic participants in the MESA trial. Higher heart rate was related to development of regional and global LV dysfunction independent of subclinical atherosclerosis and coronary heart disease. (Multi-Ethnic Study of Atherosclerosis [MESA]; NCT00005487). Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  15. Heart rate and physical activity patterns in persons with profound intellectual and multiple disabilities.

    PubMed

    Waninge, Aly; van der Putten, Annette A J; Stewart, Roy E; Steenbergen, Bert; van Wijck, Ruud; van der Schans, Cees P

    2013-11-01

    Because physical fitness and health are related to physical activity, it is important to gain an insight into the physical activity levels of persons with profound intellectual and multiple disabilities (PIMD). The purpose of this study was to examine heart rate patterns to measure the activity levels of persons with PIMD and to analyze these heart rate patterns according to participant characteristics, observed level of activity, days, and time of day. The heart rate patterns of 24 participants with PIMD were measured continuously using a heart rate monitor for 8 h · d for a period of 6 days. Physical activity levels were measured with questionnaires. Data were analyzed using multilevel analysis. The results indicate that the participants use only 32% of their heart rate reserve over 6 days. The intensity of heart rate reserve ranged from 1 to 62%. On a given day, wide ranges in heart rates between participants and within persons were observed. Between days, only small ranges in the heart rate were found. The participants could be grouped into 4 classes according to their heart rate. In addition, factors such as time of day, physical activity, and age are significantly related to heart rate patterns. In conclusion, this study is an important first step in exploring activity patterns based on heart rate patterns in persons with PIMD. The participants used relatively small fractions of their heart rate reserves. Time of day and age appear to have a considerable influence on heart rate patterns. The observed classes in heart rate patterns suggest that other probably more personal and psychosocial factors have significant influences on heart rate patterns, as well.

  16. Resting Heart Rate and Outcomes in Patients with Cardiovascular Disease: Where Do We Currently Stand?

    PubMed Central

    Menown, Ian BA; Davies, Simon; Gupta, Sandeep; Kalra, Paul R; Lang, Chim C; Morley, Chris; Padmanabhan, Sandosh

    2013-01-01

    Background Data from large epidemiological studies suggest that elevated heart rate is independently associated with cardiovascular and all-cause mortality in patients with hypertension and in those with established cardiovascular disease. Clinical trial findings also suggest that the favorable effects of beta-blockers and other heart rate–lowering agents in patients with acute myocardial infarction and congestive heart failure may be, at least in part, due to their heart rate–lowering effects. Contemporary clinical outcome prediction models such as the Global Registry of Acute Coronary Events (GRACE) score include admission heart rate as an independent risk factor. Aims This article critically reviews the key epidemiology concerning heart rate and cardiovascular risk, potential mechanisms through which an elevated resting heart rate may be disadvantageous and evaluates clinical trial outcomes associated with pharmacological reduction in resting heart rate. Conclusions Prospective randomised data from patients with significant coronary heart disease or heart failure suggest that intervention to reduce heart rate in those with a resting heart rate >70 bpm may reduce cardiovascular risk. Given the established observational data and randomised trial evidence, it now appears appropriate to include reduction of elevated resting heart rate by lifestyle +/− pharmacological therapy as part of a secondary prevention strategy in patients with cardiovascular disease. PMID:22954325

  17. Effect of energy drink dose on exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise.

    PubMed

    An, Sang Min; Park, Jong Suk; Kim, Sang Ho

    2014-03-01

    The purpose of this research was to investigate the effects of exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise on caffeine concentration of energy drink. The volunteers for this study were 15 male university student. 15 subjects were taken basic physical examinations such as height, weight and BMI before the experiment. Primary tests were examined of VO2max per weight of each subjects by graded exercise test using Bruce protocol. Each of five subject was divided 3 groups (CON, ECGⅠ, ECGⅡ) by matched method based on weight and VO2max per weight what gained of primary test for minimize the differences of exercise capacity and ingestion of each groups. For the secondary tests, the groups of subjects were taken their materials before and after exercise as a blind test. After the ingestion, subjects were experimented on exercise test of VO2max 80% by treadmill until the all-out. Heart rate was measured by 1minute interval, and respiratory variables were analyzed VO2, VE, VT, RR and so on by automatic respiratory analyzer. And exercise exhaustion time was determined by stopwatch. Moreover, HRV was measured after exercise and recovery 3 min. Among the intake groups, ECGⅡ was showed the longest of exercise exhaustion time more than CON group (p = .05). Result of heart rate during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). Result of RPE during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). In conclusion, EDGⅡ showed the significant increase of exercise exhaustion time more than CON group (p=.05) and not significant differences in HR, RPE, RER, HRV, HRR, blood pressure (p > .05). Therefore, 2.5 mg/kg(-1) ingestion of energy drink might be positive effect

  18. Assessment of cardiac autonomic functions by heart rate recovery, heart rate variability and QT dynamicity parameters in patients with acromegaly.

    PubMed

    Dural, Muhammet; Kabakcı, Giray; Cınar, Neşe; Erbaş, Tomris; Canpolat, Uğur; Gürses, Kadri Murat; Tokgözoğlu, Lale; Oto, Ali; Kaya, Ergün Barış; Yorgun, Hikmet; Sahiner, Levent; Dağdelen, Selçuk; Aytemir, Kudret

    2014-04-01

    Cardiovascular complications are the most common causes of morbidity and mortality in acromegaly. However, there is little data regarding cardiac autonomic functions in these patients. Herein, we aimed to investigate several parameters of cardiac autonomic functions in patients with acromegaly compared to healthy subjects. We enrolled 20 newly diagnosed acromegalic patients (55% female, age:45.7 ± 12.6 years) and 32 age- and gender-matched healthy subjects. All participants underwent 24 h Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting 1st, 2nd and 3rd minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV) and QT dynamicity analysis. Baseline characteristics were similar except diabetes mellitus and hypertension among groups. Mean HRR1 (29.2 ± 12.3 vs 42.6 ± 6.5, p = 0.001), HRR2 (43.5 ± 15.6 vs 61.1 ± 10.8, p = 0.001) and HRR3 (46.4 ± 16.2 vs 65.8 ± 9.8, p = 0.001) values were significantly higher in control group. HRV parameters as, SDNN [standard deviation of all NN intervals] (p = 0.001), SDANN [SD of the 5 min mean RR intervals] (p = 0.001), RMSSD [root square of successive differences in RR interval] (p = 0.001), PNN50 [proportion of differences in successive NN intervals >50 ms] (p = 0.001) and high-frequency [HF] (p = 0.001) were significantly decreased in patients with acromegaly; but low frequency [LF] (p = 0.046) and LF/HF (p = 0.001) were significantly higher in acromegaly patients. QTec (p = 0.009), QTac/RR slope (p = 0.017) and QTec/RR slope (p = 0.01) were significantly higher in patients with acromegaly. Additionally, there were significant negative correlation of disease duration with HRR2, HRR3, SDNN, PNN50, RMSSD, variability index. Our study results suggest that cardiac autonomic functions are impaired in patients with acromegaly. Further large scale studies are needed to exhibit the prognostic significance of impaired autonomic functions in patients with

  19. Effect of energy drink dose on exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise

    PubMed Central

    An, Sang Min; Park, Jong Suk; Kim, Sang Ho

    2014-01-01

    [Purpose] The purpose of this research was to investigate the effects of exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise on caffeine concentration of energy drink. [Methods] The volunteers for this study were 15 male university student. 15 subjects were taken basic physical examinations such as height, weight and BMI before the experiment. Primary tests were examined of VO2max per weight of each subjects by graded exercise test using Bruce protocol. Each of five subject was divided 3 groups (CON, ECGⅠ, ECGⅡ) by matched method based on weight and VO2max per weight what gained of primary test for minimize the differences of exercise capacity and ingestion of each groups. For the secondary tests, the groups of subjects were taken their materials before and after exercise as a blind test. After the ingestion, subjects were experimented on exercise test of VO2max 80% by treadmill until the all-out. Heart rate was measured by 1minute interval, and respiratory variables were analyzed VO2, VE, VT, RR and so on by automatic respiratory analyzer. And exercise exhaustion time was determined by stopwatch. Moreover, HRV was measured after exercise and recovery 3 min. [Results] Among the intake groups, ECGⅡ was showed the longest of exercise exhaustion time more than CON group (p = .05). Result of heart rate during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). Result of RPE during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). [Conclusion] In conclusion, EDGⅡ showed the significant increase of exercise exhaustion time more than CON group (p=.05) and not significant differences in HR, RPE, RER, HRV, HRR, blood pressure (p > .05). Therefore, 2.5 mg/kg-1 ingestion

  20. Complexity analysis of fetal heart rate preceding intrauterine demise

    PubMed Central

    Schnettler, William T.; Goldberger, Ary L.; Ralston, Steven J.; Costa, Madalena

    2016-01-01

    Background Visual non-stress test interpretation lacks the optimal specificity and observer-agreement of an ideal screening tool for intrauterine fetal demise (IUFD) syndrome prevention. Computational methods based on traditional heart rate variability have also been of limited value. Complexity analysis probes properties of the dynamics of physiologic signals that are otherwise not accessible and, therefore, might be useful in this context. Objective To explore the association between fetal heart rate (FHR) complexity analysis and subsequent IUFD. Our specific hypothesis is that the complexity of the fetal heart rate dynamics is lower in the IUFD group compared with controls. Study Design This case-control study utilized cases of IUFD at a single tertiary-care center among singleton pregnancies with at least 10 minutes of continuous electronic FHR monitoring on at least 2 weekly occasions in the 3 weeks immediately prior to fetal demise. Controls delivered a live singleton beyond 35 weeks’ gestation and were matched to cases by gestational age, testing indication, and maternal age in a 3 to 1 ratio. FHR data was analyzed using the multiscale entropy (MSE) method to derive their complexity index. In addition, pNNx, a measure of short-term heart rate variability, which in adults is ascribable primarily to cardiac vagal tone modulation, was also computed. Results 211 IUFDs occurred during the 9-year period of review, but only 6 met inclusion criteria. The median gestational age at the time of IUFD was 35.5 weeks. Three controls were matched to each case for a total of 24 subjects, and 87 FHR tracings were included for analysis. The median gestational age at the first fetal heart rate tracing was similar between groups (median [1st– 3rd quartiles] weeks: IUFD cases: 34.7 (34.4–36.2); controls: 35.3 (34.4–36.1); p=.94). The median complexity of the cases’ tracings was significantly less than the controls’ (12.44 [8.9–16.77] vs. 17.82 [15.21–22.17]; p

  1. Complexity analysis of fetal heart rate preceding intrauterine demise.

    PubMed

    Schnettler, William T; Goldberger, Ary L; Ralston, Steven J; Costa, Madalena

    2016-08-01

    Visual non-stress test interpretation lacks the optimal specificity and observer-agreement of an ideal screening tool for intrauterine fetal demise (IUFD) syndrome prevention. Computational methods based on traditional heart rate variability have also been of limited value. Complexity analysis probes properties of the dynamics of physiologic signals that are otherwise not accessible and, therefore, might be useful in this context. To explore the association between fetal heart rate (FHR) complexity analysis and subsequent IUFD. Our specific hypothesis is that the complexity of the fetal heart rate dynamics is lower in the IUFD group compared with controls. This case-control study utilized cases of IUFD at a single tertiary-care center among singleton pregnancies with at least 10min of continuous electronic FHR monitoring on at least 2 weekly occasions in the 3 weeks immediately prior to fetal demise. Controls delivered a live singleton beyond 35 weeks' gestation and were matched to cases by gestational age, testing indication, and maternal age in a 3:1 ratio. FHR data was analyzed using the multiscale entropy (MSE) method to derive their complexity index. In addition, pNNx, a measure of short-term heart rate variability, which in adults is ascribable primarily to cardiac vagal tone modulation, was also computed. 211 IUFDs occurred during the 9-year period of review, but only 6 met inclusion criteria. The median gestational age at the time of IUFD was 35.5 weeks. Three controls were matched to each case for a total of 24 subjects, and 87 FHR tracings were included for analysis. The median gestational age at the first fetal heart rate tracing was similar between groups (median [1st-3rd quartiles] weeks: IUFD cases: 34.7 (34.4-36.2); controls: 35.3 (34.4-36.1); p=.94). The median complexity of the cases' tracings was significantly less than the controls' (12.44 [8.9-16.77] vs. 17.82 [15.21-22.17]; p<.0001). Furthermore, the cases' median complexity decreased as

  2. How to avoid misinterpretation of heart rate variability power spectra?

    PubMed

    Cammann, Henning; Michel, Josef

    2002-04-01

    Spectral analysis of R-R Interval time series is increasingly used to determine periodic components of heart rate variability (HRV). Particular diagnostic relevance is assigned to a low-frequency (LF) component, associated with blood pressure regulation, and a high-frequency (HF) component, also referred to as respiratory sinus arrhythmia (RSA) in the HRV power spectra. Frequency ranges for parametrisation of power spectra have been defined for either component in numerous publications.Results obtained from examinations with standardised psychic load in which ECG and respiratory signal are continuously recorded and adequately processed have shown that the true individual frequency range of the HF component can be reliably determined only by means of characteristics of respiration (respiratory rate (RR), range and median value of RR, tidal depth). Respiratory rhythms are interindividually extremely differentiated and of individual-specific nature. In many cases LF and HF components may be totally superimposed on each other and, consequently, cannot be diagnostically evaluated.

  3. Neural network based feature extraction scheme for heart rate variability

    NASA Astrophysics Data System (ADS)

    Raymond, Ben; Nandagopal, Doraisamy; Mazumdar, Jagan; Taverner, D.

    1995-04-01

    Neural networks are extensively used in solving a wide range of pattern recognition problems in signal processing. The accuracy of pattern recognition depends to a large extent on the quality of the features extracted from the signal. We present a neural network capable of extracting the autoregressive parameters of a cardiac signal known as hear rate variability (HRV). Frequency specific oscillations in the HRV signal represent heart rate regulatory activity and hence cardiovascular function. Continual monitoring and tracking of the HRV data over a period of time will provide valuable diagnostic information. We give an example of the network applied to a short HRV signal and demonstrate the tracking performance of the network with a single sinusoid embedded in white noise.

  4. Heart Rate Variability in Sleep-Related Migraine without Aura

    PubMed Central

    Vollono, Catello; Gnoni, Valentina; Testani, Elisa; Dittoni, Serena; Losurdo, Anna; Colicchio, Salvatore; Di Blasi, Chiara; Mazza, Salvatore; Farina, Benedetto; Della Marca, Giacomo

    2013-01-01

    Objectives: This is an observational study aimed to investigate the activity of autonomic nervous system during sleep in patients with sleep-related migraine. Methods: Eight consecutive migraineurs without aura were enrolled (6 women and 2 men), aged 30 to 62 years (mean 48.1 ± 9.3 years). Inclusion criteria were: high frequency of attacks (> 5 per month) and occurrence of more than 75% of the attacks during sleep causing an awakening. Patients were compared with a control group of 55 healthy subjects (23 men and 32 women, mean age 54.2 ± 13.0 years), and with a further control group of 8 age- and gender-matched healthy controls. Patient and controls underwent polysomnography and heart rate variability analysis. Results: A significant reduction of the LF/HF ratio during N2 and N3 sleep stages was observed in migraineurs compared with controls. No differences in sleep macrostructure were observed; cyclic alternating pattern (CAP) time and CAP rate were lower in migraineurs than in controls. Conclusions: These findings indicate a peculiar modification of the autonomic balance during sleep in sleep-related migraine. The reduction of LF/HF ratio in NREM sleep was observed in controls, but it was quantitatively much more evident in migraineurs. Changes in LF/HF could be consequent to an autonomic unbalance which could manifest selectively (or alternatively become more evident) during sleep. These findings, together with the reduction in CAP rate, could be an expression of reduced arousability during sleep in patients with sleep-related migraine. The simultaneous involvement of the autonomic, arousal, and pain systems might suggest involvement of the hypothalamic pathways. Citation: Vollono C; Gnoni V; Testani E; Dittoni S; Losurdo A; Colicchio S; Di Blasi C; Mazza S; Farina B; Della Marca G. Heart rate variability in sleep-related migraine without aura. J Clin Sleep Med 2013;9(7):707-714. PMID:23853566

  5. Exercise stroke volume and heart rate response differ in right and left heart failure.

    PubMed

    Groepenhoff, Herman; Westerhof, Nico; Jacobs, Wouter; Boonstra, Anco; Postmus, Piet E; Vonk-Noordegraaf, Anton

    2010-07-01

    In pulmonary arterial hypertension (PAH), the exercise-induced increase in stroke volume (SV) is limited by the increase in pulmonary artery pressure. In left heart failure (LHF), systemic arterial pressure increases little during exercise, and the SV increase is limited by the left ventricle itself. These differences might be reflected by a dissimilar SV and heart rate (HR) response to exercise, which could have important therapeutic implications, for example in beta-blocker therapy. Therefore, we tested the hypothesis that SV and HR responses during exercise are different between PAH and LHF patients. We included 28 PAH and 18 LHF patients (recruited from the heart failure unit) matched on a maximal oxygen uptake of <15 mL/kg/min, who were referred to our Pulmonary Function Department between 2000 and 2008 for a maximal cardio-pulmonary exercise test. Only patients who had not been exposed to beta-blockers were included. Pulmonary arterial hypertension and LHF patient groups had equally impaired exercise tolerance (about 42% of predicted) with a maximal oxygen uptake of 0.80 +/- 0.29 and 0.86 +/- 0.19 L/min. The peak SV response to exercise was significantly lower in PAH patients (-14 mL, P = 0.01); this was compensated by a steeper slope of HR relating to oxygen uptake (0.03 beats/mL, P = 0.001). We conclude that PAH patients have a smaller SV response, but a larger HR response than LHF patients.

  6. Prognostic significance of heart rate turbulence parameters in patients with chronic heart failure

    PubMed Central

    2014-01-01

    Background This study is aimed to evaluate the clinical significance of heart rate turbulence (HRT) parameters in predicting the prognosis in patients with chronic heart failure (CHF). Methods From June 2011 to December 2012, a total of 104 CHF patients and 30 healthy controls were enrolled in this study. We obtained a 24-hour Holter ECG recording to assess the HRT parameters, included turbulence onset (TO), turbulence slope (TS), standard deviation of N-N intervals (SDNN), and resting heart rate (RHR). The relationships between HRT parameters and the prognosis of CHF patients were determined. Results The assessment follow-up period lasted until January 31, 2013. The overall mortality of CHF patients was 9.6% (10/104). Our results revealed that CHF patients had higher levels of TO than those of healthy subjects, but the TS levels of CHF patients were lower than that of the control group. CHF patients with NYHA grade IV had higher HRT1/2 rate than those with NYHA grade II/III. There were statistical differences in TS, LVEF, SDNN and RHR between the non-deteriorating group and the non-survivor group. Significant differences in TS among the three groups were also found. Furthermore, CHF patients in the non-survivor group had lower levels of TS than those in the deteriorating group. Correlation analyses indicated that TO negatively correlate with SDNN, while TS positively correlated with SDNN and left ventricular ejection fraction (LVEF). We also observed negative correlations between TS and left ventricular end-diastolic cavity dimension (LVEDD), RHR, homocysteine (Hcy) and C-reactive protein (CRP). Multivariate Cox regression analysis further confirmed that LVEF (≤30%), HRT2, SDNN and RHR were independent risk factors which can indicate poor prognosis in CHF patients. Conclusions Our findings indicate that HRT may have good clinical predictive value in patients with CHF. Thus, quantifying HRT parameters could be a useful tool for predicting mortality in CHF

  7. Newborn infant pain assessment using heart rate variability analysis.

    PubMed

    Faye, Papa M; De Jonckheere, Julien; Logier, Regis; Kuissi, Eliane; Jeanne, Mathieu; Rakza, Thameur; Storme, Laurent

    2010-01-01

    Systems controlling cardiovascular function are closely coupled with the perception of pain. Heart rate variability (HRV) is a well-established noninvasive measure of cardiac autonomic control. We hypothesized that pain may alter HRV in the newborn infant and that HRV analysis could be used as an indicator of prolonged pain in the newborn infant. To test the hypothesis, we measured the magnitude of the heart rate high-frequency variations using an innovative High Frequency Variability Index (HFVI) in newborn infants at risk of postoperative pain. We investigated newborn infants with a gestational age (GA) more than 34 weeks, and who were admitted after a major surgical procedure. Inclusions ranged from 2 to 72 hours after the surgery. The postoperative pain was scored using EDIN scale (neonatal pain and discomfort scale) at the end of the 2 hours recording period. The infants were separated in: (1) Group "Low EDIN," when EDIN<5; and (2) Group "High EDIN," when EDIN >=5. Predictive positive and negative values of a threshold value of HFVI in assessing pain have been studied. Twenty-eight newborn infants were enrolled in the study (mean GA=37.8+/-1.5 wk) at a median delay between the surgery and the recording of 5 hours. Mean EDIN were 2+/-1 and 7+/-2 in respectively the groups "Low EDIN" and "High EDIN." The 2 groups were similar for GA, basal heart and respiratory rates, SpO2, mean arterial blood pressure, and morphine infusion rate. HFVI was significantly lower in the group "High EDIN" than in the group "Low EDIN" (0.7+/-0.2 vs. 1.2+/-0.3, respectively; P<0.01). An HFVI <0.9 was able to predict an EDIN score >=5, with a sensitivity of 90%, and a specificity of 75%. The results of this study indicate that postoperative pain is associated with a decreased high-frequency HRV in full-term newborn infants. Our findings suggest that HRV could be used as an indicator to assess prolonged pain in the newborn infants.

  8. Comparison of pulse rate variability with heart rate variability during obstructive sleep apnea.

    PubMed

    Khandoker, Ahsan H; Karmakar, Chandan K; Palaniswami, Marimuthu

    2011-03-01

    We investigate whether pulse rate variability (PRV) extracted from finger photo-plethysmography (Pleth) waveforms can be the substitute of heart rate variability (HRV) from RR intervals of ECG signals during obstructive sleep apnea (OSA). Simultaneous measurements (ECG and Pleth) were taken from 29 healthy subjects during normal (undisturbed sleep) breathing and 22 patients with OSA during OSA events. Highly significant (p<0.01) correlations (1.0>r>0.95) were found between heart rate (HR) and pulse rate (PR). Bland-Altman plot of HR and PR shows good agreement (<5% difference). Comparison of 2 min recording epochs demonstrated significant differences (p<0.01) in time, frequency domains and complexity analysis, between normal and OSA events using PRV as well as HRV measures. Results suggest that both HRV and PRV indices could be used to distinguish OSA events from normal breathing during sleep. However, several variability measures (SDNN, RMSSD, HF power, LF/HF and sample entropy) of PR and HR were found to be significantly (p<0.01) different during OSA events. Therefore, we conclude that PRV provides accurate inter-pulse variability to measure heart rate variability under normal breathing in sleep but does not precisely reflect HRV in sleep disordered breathing. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

  9. Acetylcholinesterase inhibition with pyridostigmine improves heart rate recovery after maximal exercise in patients with chronic heart failure

    PubMed Central

    Androne, A S; Hryniewicz, K; Goldsmith, R; Arwady, A; Katz, S D

    2003-01-01

    Objective: To characterise the effects of acetylcholinesterase inhibition with pyridostigmine on parasympathetic tone in patients with chronic heart failure (CHF). Design: Prospective randomised, double blind crossover trial. Setting: University hospital outpatient heart failure clinic. Patients: 20 ambulatory subjects with stable CHF (mean age 55 years, mean ejection fraction 24%). Interventions: Oral administration of a single dose of pyridostigmine 30 mg and matching placebo on separate days. Main outcome measures: Heart rate recovery at one minute and three minutes after completion of maximal exercise. Results: Heart rate recovery at one minute after exercise was significantly greater after administration of pyridostigmine than after administration of placebo (mean (SEM) 27.4 (3.2) beats/min v 22.4 (2.4) beats/min, p < 0.01). Heart rate recovery at three minutes after exercise did not differ after administration of pyridostigmine and placebo (mean (SEM) 44.4 (3.9) beats/min v 41.8 (3.6) beats/min, NS). Peak heart rate, peak oxygen uptake, peak respiratory exchange ratio, plasma noradrenaline (norepinephrine) concentrations, and plasma brain natriuretic peptide concentrations did not differ after administration of pyridostigmine and placebo. Conclusions: Acetylcholinesterase inhibition with pyridostigmine increased heart rate recovery at one minute but not at three minutes after exercise. A specific effect of pyridostigmine on heart rate one minute after exercise suggests that pyridostigmine augments parasympathetic tone in patients with CHF. PMID:12860856

  10. Effects of functional water on heart rate, heart rate variability, and salivary immunoglobulin a in healthy humans: a pilot study.

    PubMed

    Johansson, Benny

    2009-08-01

    This study was designed to explore the effects of drinking an average dietary volume of functional water on blood pressure, short-term cardiovascular variables, and salivary immunoglobulin A. Subjects were studied in a randomized pre-post crossover design the morning after an overnight fast. Fifteen (15) healthy nonsmoking subjects, 8 males and 7 females, aged between 15 and 49 years, participated in the study. Short-term (10 minute) electrocardiography was measured in the participants before and after drinking either control mineral or functional water. The measurements were randomized, double blinded, and held two weeks apart. Saliva was collected for 4 minutes before the start of each electrocardiograph measurement. Blood pressure was monitored at 5 minute intervals for one hour as the mean of triplicate consecutive measurements. Drinking 100 mL of control mineral or functional water did not alter arterial blood pressure in the 60 minutes post-drinking. Drinking control mineral water led to a significant fall in the heart rate, although all time domain and power density parameters remained unaffected. Consumption of functional water resulted in a significant difference in all time domain measures and in three of the power density parameters. The heart rate fell, while RR interbeat intervals, standard deviation of the normal-to-normal heartbeats (SDNN), and the square root of the mean squared differences of successive NN intervals (RMSSD) increased. A large rise in low (LF) and high frequency (HF) power had a significant effect on total power, indicating homeodynamic balance. Elevated LF power indicated intensified spectral power at frequencies in the range of 0.1 Hz, thus improving autonomic stability. The effect on the heart rate may confirm changes in cellular metabolism. Parasympathetic pathway activation stimulated secretory immunoglobulin A on mucosal surfaces, which protects against pathogenic invasion. The drinking of functional water in healthy subjects

  11. Hierarchical Structure of Heart Rate Variability in Humans

    NASA Astrophysics Data System (ADS)

    Gao, X. Z.; Ching, E. S. C.; Lin, D. C.

    2004-03-01

    We show a hierarchical structure (HS) of the She-Leveque form in the beat-to-beat RR intervals of heart rate variability (HRV) in humans. This structure, first found as an empirical law in turbulent fluid flows, implies further details in the HRV multifractal scaling. We tested HS using daytime RRi data from healthy subjects and heart diseased patients with congestive heart failure and found a universal law C(b) where b characterizes the multifractality of HRV and C is related to a co-dimension parameter of the most violent events in the fluctuation. The potential of diagnosis is discussed based on the characteristics of this finding. To model the HRV phenomenology, we propose a local-feedback-global-cascade (LFGC) model based on the She-Waymire (SW) cascade solution to the HS in fluid turbulence. This model extends from the previous work in that it integrates additive law multiplicatively into the cascade structure. It is an attempt to relate to the cardiovascular physiology which consists of numerous feedback controls that function primarily on the principle of additive law. In particular, the model is based on the same philosophy as the SW cascade that its multifractal dynamics consists of a singular and a modulating component. In the LFGC model, we introduce local feedback to model the dynamics of the modulating effect. The novelty of our model is to incorporate the cascade structure in the scheduling for the feedback control. This model also represents an alternative solution to the HS. We will present the simulation results by the LFGC model and discuss its implication in physiology terms.

  12. Heart rate and blood pressure: any possible implications for management of hypertension?

    PubMed

    Reule, Scott; Drawz, Paul E

    2012-12-01

    Hypertension is a common clinical problem and a major risk factor for cardiovascular disease and stroke. Elevated heart rate is associated with elevated blood pressure, increased risk for hypertension, and, among hypertensives, increased risk for cardiovascular disease. Despite these important relationships, heart rate is generally not a major consideration in choosing antihypertensive medications. In part, this is due to a lack of evidence supporting heart rate lowering as a therapeutic strategy in hypertension. Additionally, while there is a positive correlation between heart rate and peripheral blood pressure, there is an inverse relationship between heart rate and central blood pressure. The use of antihypertensive medications, specifically medications that affect heart rate, may not reliably reduce central blood pressure to a similar extent as observed peripherally. We review the relationship between heart rate and peripheral and central blood pressure, with a focus on the implications for chronotropic therapy in hypertension.

  13. Heart rates increase after hatching in two species of Natricine snakes.

    PubMed

    Aubret, Fabien

    2013-11-29

    Experimental studies have shown heart rates to decrease from embryo to hatchling stage in turtles, remain steady in skinks, and increase in birds. However, no snake species has been studied in this regard. I recorded heart rate evolution trajectories from embryo to juvenile stage in 78 eggs from two species of European Natricine snakes. Unexpectedly, snakes behaved more like birds than turtles or lizards: heart rates increased after hatching in both N. maura and N. natrix, respectively by 43.92 ± 22.84% and 35.92 ± 24.52%. Heart rate shift was not related to an abrupt elevation of metabolism per se (snakes that increased their heart rates the most sharply grew the least after birth), but rather due to a number of smaller eggs that experienced lower than normal heart rates throughout the incubation and recovered a normal heart rate post-birth. This finding is discussed in the light of hatching synchrony benefits.

  14. Heart rates increase after hatching in two species of natricine snakes

    PubMed Central

    Aubret, Fabien

    2013-01-01

    Experimental studies have shown heart rates to decrease from embryo to hatchling stage in turtles, remain steady in skinks, and increase in birds. However, no snake species has been studied in this regard. I recorded heart rate evolution trajectories from embryo to juvenile stage in 78 eggs from two species of European Natricine snakes. Unexpectedly, snakes behaved more like birds than turtles or lizards: heart rates increased after hatching in both N. maura and N. natrix, respectively by 43.92 ± 22.84% and 35.92 ± 24.52%. Heart rate shift was not related to an abrupt elevation of metabolism per se (snakes that increased their heart rates the most sharply grew the least after birth), but rather due to a number of smaller eggs that experienced lower than normal heart rates throughout the incubation and recovered a normal heart rate post-birth. This finding is discussed in the light of hatching synchrony benefits. PMID:24287712

  15. The effect of ATP-sensitive potassium channel modulation on heart rate in isolated muskrat and guinea pig hearts.

    PubMed

    Streeby, D R; McKean, T A

    1994-12-01

    Muskrats (Ondontra zibethicus) are common freshwater diving mammals exhibiting a bradycardia with both forced and voluntary diving. This bradycardia is mediated by vagal innervation; however, if hypoxia is present there may be local factors that also decrease heart rate. Some of these local factors may include ATP-sensitive potassium channel activation and extracellular accumulation of potassium ions, hydrogen ions and lactate. The purpose of this study was to investigate the role of these factors in the isolated perfused hearts of muskrats and of a non-diving mammal, the guinea pig. Although lactate and proton administration reduced heart rate in isolated muskrat and guinea pig hearts, there was no difference in the response to lactate and proton infusion between the two species. Muskrat hearts were more sensitive to the heart-rate-lowering effects of exogenously applied potassium than were guinea pig hearts. Early increases in extracellular potassium concentration during hypoxia are thought to be mediated by the ATP-sensitive potassium channel. Activation of these channels under normoxic conditions had a mildly negative chronotropic effect in both species; however, activation of these channels with Lemakalim under hypoxic conditions caused the guinea pig heart to respond with an augmented bradycardia similar to that seen in the hypoxic muskrat heart in the absence of drugs. Inhibition of these channels by glibenclamide during hypoxia was partially successful in blocking the bradycardia in guinea pig hearts, but inhibition of the same channels in hypoxic muskrat hearts had a damaging effect as two of five hearts went into contracture during the hypoxia. Thus, although ATP-sensitive potassium channels appear to have a major role in the bradycardia of hypoxia in guinea pigs, the failure to prevent the bradycardia by inhibition of these channels in muskrat hearts suggests that multiple factors are involved in the hypoxia-induced bradycardia in this species.

  16. Combined effects of molt and chronic stress on heart rate, heart rate variability, and glucocorticoid physiology in European starlings.

    PubMed

    Kostelanetz, Sophia; Dickens, Molly J; Romero, L Michael

    2009-12-01

    Molt is an important life-history stage in avian species, but little is known about the effects of chronic stress during this period. Three weeks after the onset of molt, captive European starlings (Sturnus vulgaris) were exposed to 18 days of chronic stress, induced with four 30-minute randomized stressors presented daily. Birds showed no chronic-stress-induced changes in heart rate or heart rate variability when measured either during the middle of the day or at night. These data suggest that chronic stress did not alter the balance between sympathetic and parasympathetic nervous system regulation of cardiovascular function, which contrasts with data from an earlier study indicating that chronic stress profoundly alters cardiovascular function in non-molting starlings. Additionally, there was a significant increase in restraint-induced corticosterone secretion the first week of chronic stress that subsequently returned to pre-chronic-stress levels by the second week of exposure. The attenuated corticosterone response again contrasts with data from non-molting starlings that showed significant decreases in corticosterone responses. Consequently, the resistance to cardiovascular and corticosterone changes indicates that the physiological changes induced by chronic stress are greatly attenuated in molting birds. Overall, the data suggest that molt requires a degree of physiological stability that must be protected, so that if a bird is exposed to chronic stress during this life-history stage, molt takes priority.

  17. Influence of polyunsaturated fatty acids on blood pressure, resting heart rate and heart rate variability among French Polynesians.

    PubMed

    Valera, Beatriz; Suhas, Edouard; Counil, Emilie; Poirier, Paul; Dewailly, Eric

    2014-01-01

    To analyze the associations between marine n-3 polyunsaturated fatty acids (PUFAs) and blood pressure (BP), resting heart rate (HR), and heart rate variability (HRV) in a population highly exposed to methylmercury through the diet. Concentrations of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in erythrocytes membranes were measured in 180 French Polynesian adults (≥18 years) residing in Tubuai, which is a community with a traditional lifestyle, or Papeete, which has a modern lifestyle. HRV was measured using a 2-hour ambulatory electrocardiogram (Holter). Resting HR and BP were measured using standardized protocols and pulse pressure (PP) was calculated as systolic BP - diastolic BP. The associations between n-3 PUFAs and the dependent variables were studied using simple and multiple linear regressions. Increasing DHA concentration was associated with lower resting HR (β = -2.57, p = 0.005) and diastolic BP (β = -1.96, p = 0.05) and higher HRV in multivariable models. Specifically, DHA was associated with high frequency (HF; β = 0.19, p = 0.02) and the square root of the mean squared differences of successive R-R intervals (difference between two consecutive R waves; rMSSD; β = 0.08, p = 0.03), which are specific indices of the parasympathetic activity of the autonomic nervous system. DHA was associated with lower BP and resting HR and higher HRV among French Polynesians who are also exposed to high methylmercury levels.

  18. Resting heart rate, heart rate reserve, and metabolic syndrome in professional firefighters: A cross-sectional study.

    PubMed

    Choi, BongKyoo; Ko, SangBaek; Kojaku, Stacey

    2017-10-01

    Little is known about the associations of resting heart rate (RHR) and heart rate reserve (HRR) with metabolic syndrome (MetS) in firefighters. For each of 288 professional firefighters, HRR was calculated as the difference between measured RHR and estimated maximum HR. For comparison, VO2 max based on a treadmill test was included. MetS was defined according to the NCEP/ATP III criteria. The prevalence of MetS was 14.2%. The average of RHR was 61.5 beat/min. Only 5.8% of the firefighters had RHR of ≥80 beat/min. Between the firefighters in the lowest and highest quintiles, the prevalence ratios (95% confidence intervals) for MetS were 1.88 (0.71-4.94), 5.90 (1.74-20.02), and 8.03 (1.86-34.75) for RHR, HRR, and VO2 max, respectively. Both HRR and VO2 max, but not RHR, were significantly associated with MetS and its most component risk factors in middle-aged firefighters. HRR, a simple cardiovascular fitness measure, was inversely associated with MetS among middle-aged professional firefighters. © 2017 Wiley Periodicals, Inc.

  19. Heart rate-based window segmentation improves accuracy of classifying posttraumatic stress disorder using heart rate variability measures

    PubMed Central

    Reinertsen, Erik; Nemati, Shamim; Vest, Adriana N; Vaccarino, Viola; Lampert, Rachel; Shah, Amit J; Clifford, Gari D

    2017-01-01

    Objective Heart rate variability (HRV) characterizes changes in autonomic nervous system function and varies with posttraumatic stress disorder (PTSD). In this study we developed a classifier based on heart rate (HR) and HRV measures, and improved classifier performance using a novel HR-based window segmentation. Approach Single-channel ECG data were collected from 23 subjects with current PTSD, and 25 control subjects with no history of PTSD over 24 h. RR intervals were derived from these data, cleaned, and used to calculate HR and HRV metrics. These metrics were used as features in a logistic regression classifier. Performance was assessed via repeated random sub-sampling validation. To reduce noise and activity-related effects, we calculated features from five non-overlapping ten-minute quiescent segments of RR intervals defined by lowest HR, as well as random ten-minute segments as a control. Main Results Using a combination of the four most predictive features derived from quiescent segments we achieved a median area under the receiver operating curve (AUC) of 0.86 on out-of-sample test set data. This was significantly higher than the AUC using 24 h of data (0.72) or random segments (0.67). Significance These results demonstrate our segmentation approach improves the classification of PTSD from HR and HRV measures, and suggest the potential for tracking PTSD illness severity via objective physiological monitoring. Future studies should prospectively evaluate if classifier output changes significantly with worsening or effective treatment of PTSD. PMID:28489609

  20. Heart rate-based window segmentation improves accuracy of classifying posttraumatic stress disorder using heart rate variability measures.

    PubMed

    Reinertsen, Erik; Nemati, Shamim; Vest, Adriana N; Vaccarino, Viola; Lampert, Rachel; Shah, Amit J; Clifford, Gari D

    2017-06-01

    Heart rate variability (HRV) characterizes changes in autonomic nervous system function and varies with posttraumatic stress disorder (PTSD). In this study we developed a classifier based on heart rate (HR) and HRV measures, and improved classifier performance using a novel HR-based window segmentation. Single-channel ECG data were collected from 23 subjects with current PTSD, and 25 control subjects with no history of PTSD over 24 h. RR intervals were derived from these data, cleaned, and used to calculate HR and HRV metrics. These metrics were used as features in a logistic regression classifier. Performance was assessed via repeated random sub-sampling validation. To reduce noise and activity-related effects, we calculated features from five non-overlapping ten-minute quiescent segments of RR intervals defined by lowest HR, as well as random ten-minute segments as a control. Using a combination of the four most predictive features derived from quiescent segments we achieved a median area under the receiver operating curve (AUC) of 0.86 on out-of-sample test set data. This was significantly higher than the AUC using 24 h of data (0.72) or random segments (0.67). These results demonstrate our segmentation approach improves the classification of PTSD from HR and HRV measures, and suggest the potential for tracking PTSD illness severity via objective physiological monitoring. Future studies should prospectively evaluate if classifier output changes significantly with worsening or effective treatment of PTSD.

  1. Chemical sympathectomy restores baroreceptor-heart rate reflex and heart rate variability in rats with chronic nitric oxide deficiency.

    PubMed

    Chaswal, M; Das, S; Prasad, J; Katyal, A; Fahim, M

    2015-01-01

    Nitric oxide (NO) plays a crucial role not only in regulation of blood pressure but also in maintenance of cardiac autonomic tone and its deficiency induced hypertension is accompanied by cardiac autonomic dysfunction. However, underlying mechanisms are not clearly defined. We hypothesized that sympathetic activation mediates hemodynamic and cardiac autonomic changes consequent to deficient NO synthesis. We used chemical sympathectomy by 6-hydroxydopamine to examine the influence of sympathetic innervation on baroreflex sensitivity (BRS) and heart rate variability (HRV) of chronic N(G)-nitro-L-arginine methyl ester (L-NAME) treated adult Wistar rats. BRS was determined from heart rate responses to changes in systolic arterial pressure achieved by intravenous administration of phenylephrine and sodium nitroprusside. Time and frequency domain measures of HRV were calculated from 5-min electrocardiogram recordings. Chronic L-NAME administration (50 mg/kg per day for 7 days orally through gavage) in control rats produced significant elevation of blood pressure, tachycardia, attenuation of BRS for bradycardia and tachycardia reflex and fall in time as well as frequency domain parameters of HRV. Sympathectomy completely abolished the pressor as well as tachycardic effect of chronic L-NAME. In addition, BRS and HRV improved after removal of sympathetic influence in chronic L-NAME treated rats. These results support the concept that an exaggerated sympathetic activity is the principal mechanism of chronic L-NAME hypertension and associated autonomic dysfunction.

  2. T-box genes coordinate regional rates of proliferation and regional specification during cardiogenesis.

    PubMed

    Cai, Chen-Leng; Zhou, Wenlai; Yang, Lei; Bu, Lei; Qyang, Yibing; Zhang, Xiaoxue; Li, Xiaodong; Rosenfeld, Michael G; Chen, Ju; Evans, Sylvia

    2005-05-01

    Mutations in T-box genes are the cause of several congenital diseases and are implicated in cancer. Tbx20-null mice exhibit severely hypoplastic hearts and express Tbx2, which is normally restricted to outflow tract and atrioventricular canal, throughout the heart. Tbx20 mutant hearts closely resemble those seen in mice overexpressing Tbx2 in myocardium, suggesting that upregulation of Tbx2 can largely account for the cardiac phenotype in Tbx20-null mice. We provide evidence that Tbx2 is a direct target for repression by Tbx20 in developing heart. We have also found that Tbx2 directly binds to the Nmyc1 promoter in developing heart, and can repress expression of the Nmyc1 promoter in transient transfection studies. Repression of Nmyc1 (N-myc) by aberrantly regulated Tbx2 can account in part for the observed cardiac hypoplasia in Tbx20 mutants. Nmyc1 is required for growth and development of multiple organs, including the heart, and overexpression of Nmyc1 is associated with childhood tumors. Despite its clinical relevance, the factors that regulate Nmyc1 expression during development are unknown. Our data present a paradigm by which T-box proteins regulate regional differences in Nmyc1 expression and proliferation to effect organ morphogenesis. We present a model whereby Tbx2 directly represses Nmyc1 in outflow tract and atrioventricular canal of the developing heart, resulting in relatively low proliferation. In chamber myocardium, Tbx20 represses Tbx2, preventing repression of Nmyc1 and resulting in relatively high proliferation. In addition to its role in regulating regional proliferation, we have found that Tbx20 regulates expression of a number of genes that specify regional identity within the heart, thereby coordinating these two important aspects of organ development.

  3. Unobtrusive heart rate monitor based on a fiber specklegram sensor and a single-board computer

    NASA Astrophysics Data System (ADS)

    Benevides, Alessandro B.; Frizera, Anselmo; Cotrina, Anibal; Ribeiro, Moisés. R. N.; Segatto, Marcelo E. V.; Pontes, Maria José

    2015-09-01

    This paper proposes a portable and unobtrusive heart rate monitor based on fiber specklegram sensors. The proposed module uses the Raspberry Pi module to perform the image acquisition and the fiber specklegram sensor, which is based on multimode plastic optical fibers. The heart rate is obtained by welch power spectral density estimate and the heart beats are identified by means of a threshold analysis.

  4. Problem Behavior and Heart Rate Reactivity in Adopted Adolescents: Longitudinal and Concurrent Relations

    ERIC Educational Resources Information Center

    Bimmel, Nicole; van IJzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Juffer, Femmie; De Geus, Eco J. C.

    2008-01-01

    The present longitudinal study examined resting heart rate and heart rate variability and reactivity to a stressful gambling task in adopted adolescents with aggressive, delinquent, or internalizing behavior problems and adopted adolescents without behavior problems (total N=151). Early-onset delinquent adolescents showed heart rate…

  5. Problem Behavior and Heart Rate Reactivity in Adopted Adolescents: Longitudinal and Concurrent Relations

    ERIC Educational Resources Information Center

    Bimmel, Nicole; van IJzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Juffer, Femmie; De Geus, Eco J. C.

    2008-01-01

    The present longitudinal study examined resting heart rate and heart rate variability and reactivity to a stressful gambling task in adopted adolescents with aggressive, delinquent, or internalizing behavior problems and adopted adolescents without behavior problems (total N=151). Early-onset delinquent adolescents showed heart rate…

  6. Exercise Training Improves Heart Rate Variability after Methamphetamine Dependency

    PubMed Central

    Dolezal, Brett A.; Chudzynski, Joy; Dickerson, Daniel; Mooney, Larissa; Rawson, Richard A.; Garfinkel, Alan; Cooper, Christopher B.

    2014-01-01

    Purpose Heart rate variability (HRV) reflects a healthy autonomic nervous system and is increased with physical training. Methamphetamine dependence (MD) causes autonomic dysfunction and diminished HRV. We compared recently abstinent MD participants with age-matched, drug free controls (DF) and also investigated whether HRV can be improved with exercise training in the MD participants. Methods In 50 participants (MD=28; DF=22) resting heart rate (R-R intervals) was recorded over 5 min while seated using a monitor affixed to a chest strap. Previously reported time-domain (SDNN, RMSSD, pNN50) and frequency-domain (LFnu, HFnu, LF/HF) parameters of HRV were calculated with customized software. MD were randomized to thrice weekly exercise training (ME=14) or equal attention without training (MC=14) over 8 weeks. Groups were compared using paired and unpaired t-tests. Statistical significance was set at P≤0.05. Results Participant characteristics were matched between groups: age 33±6 years; body mass 82.7±12 kg, BMI 26.8±4.1 kg•min−2, mean±SD. Compared with DF, the MD group had significantly higher resting heart rate (P<0.05), LFnu, and LF/HF (P<0.001) as well as lower SDNN, RMSSD, pNN50 and HFnu (all P<0.001). At randomization, HRV indices were similar between ME and MC groups. However, after training, the ME group significantly (all P<0.001) increased SDNN (+14.7±2.0 ms, +34%), RMSSD (+19.6±4.2 ms, +63%), pNN50 (+22.6±2.7%, +173%), HFnu (+14.2±1.9, +60%) and decreased HR (−5.2±1.1 beats·min−1, −7%), LFnu (−9.6±1.5, −16%) and LF/HF (−0.7±0.3, −19%). These measures did not change from baseline in the MC group. Conclusion HRV, based on several conventional indices, was diminished in recently abstinent, methamphetamine dependent individuals. Moreover, physical training yielded a marked increase of HRV representing increased vagal modulation or improved autonomic balance. PMID:24162556

  7. CAFFEINE IMPROVES HEART RATE WITHOUT IMPROVING SEPSIS SURVIVAL

    PubMed Central

    Bauzá, Gustavo; Remick, Daniel

    2015-01-01

    Introduction Caffeine is consumed on a daily basis for its nervous system stimulant properties and is a global adenosine receptor antagonist. Since adenosine receptors have been found to play a major role in regulating the immune response to a septic insult, we investigated if caffeine consumption prior to a septic insult would alter immunological and physiological responses, as well as survival. Methods Two separate experimental designs were employed, both using outbred female ICR mice. In the first experiment mice were administered 20mg/kg of caffeine (equal to 2–3 cups of coffee for a human) or normal saline intraperitoneally at the time of cecal ligation and puncture (CLP). Immunological parameters including cytokines and local cell recruitment measured. In the second experiment caffeine (10mg/kg/hr) was delivered continuously for 24 hours via a subcutaneous infusion pump placed the day prior to CLP and hemodynamic parameters were examined. In both experiments survival was followed for five days. Results A single dose of caffeine at the initiation of sepsis did not alter survival. This single dose of caffeine did significantly increase in plasma levels of the chemokine KC six hours after the onset of sepsis compared to septic mice given normal saline. There were no changes in IL-6 or IL-10 levels in the caffeine groups. Peritoneal lavages performed 24 hours post-CLP showed no difference in the levels of IL-6, TNF, KC, MIP-1, IL-10 or the IL-1 receptor antagonist between caffeine and normal saline treated mice. Additionally, the lavages yielded similar numbers of cells (4.1×106 vehicle vs. 6.9×106 caffeine) and bacterial colony forming units (CFU, 4.1 million CFU vehicle vs. 2.8 million CFU caffeine). In the infusion group, caffeine also did not alter survival. However, caffeine infusion did increase heart rate prior to CLP, and prevented the decline in heart rate after CLP. Conclusion Caffeine increased heart rate in mice but does not impact cytokine

  8. Validation of Biofeedback Wearables for Photoplethysmographic Heart Rate Tracking

    PubMed Central

    Jo, Edward; Lewis, Kiana; Directo, Dean; Kim, Michael J.; Dolezal, Brett A.

    2016-01-01

    The purpose of this study was to examine the validity of HR measurements by two commercial-use activity trackers in comparison to ECG. Twenty-four healthy participants underwent the same 77-minute protocol during a single visit. Each participant completed an initial rest period of 15 minutes followed by 5 minute periods of each of the following activities: 60W and 120W cycling, walking, jogging, running, resisted arm raises, resisted lunges, and isometric plank. In between each exercise task was a 5-minute rest period. Each subject wore a Basis Peak (BPk) on one wrist and a Fitbit Charge HR (FB) on the opposite wrist. Criterion measurement of HR was administered by 12-lead ECG. Time synced data from each device and ECG were concurrently and electronically acquired throughout the entire 77-minute protocol. When examining data in aggregate, there was a strong correlation between BPk and ECG for HR (r = 0.92, p < 0.001) with a mean bias of -2.5 bpm (95% LoA 19.3, -24.4). The FB demonstrated a moderately strong correlation with ECG for HR (r = 0.83, p < 0.001) with an average mean bias of -8.8 bpm (95% LoA 24.2, -41.8). During physical efforts eliciting ECG HR > 116 bpm, the BPk demonstrated an r = 0.77 and mean bias = -4.9 bpm (95% LoA 21.3, -31.0) while the FB demonstrated an r = 0.58 and mean bias = -12.7 bpm (95% LoA 28.6, -54.0). The BPk satisfied validity criteria for HR monitors, however showed a marginal decline in accuracy with increasing physical effort (ECG HR > 116 bpm). The FB failed to satisfy validity criteria and demonstrated a substantial decrease in accuracy during higher exercise intensities. Key points Modern day wearable multi-sensor activity trackers incorporate reflective photoplethymography (PPG) for heart rate detection and monitoring at the dorsal wrist. This study examined the validity of two PPG-based activity trackers, the Basis Peak and Fitbit Charge HR. The Basis Peak performed with accuracy compared with ECG and results substantiate

  9. Heart rate variability and methylphenidate in children with ADHD.

    PubMed

    Buchhorn, Reiner; Conzelmann, Annette; Willaschek, Christian; Störk, Dagmar; Taurines, Regina; Renner, Tobias J

    2012-06-01

    Although an extensive number of studies support the efficacy and tolerability of stimulants in the treatment of attention deficit/hyperactivity disorder (ADHD), in recent years, increasing concerns have been raised about their cardiovascular safety. We investigated whether a time domain analysis of heart rate variability (HRV) recordings in 24-h ECG under medication with stimulants yielded new information about therapy control in ADHD. We analysed the HRV parameter standard deviation of all normal sinus RR intervals over 24 h (SDNN), percentage of successive normal sinus RR intervals > 50 ms (pNN50) and root-mean-square of the successive normal sinus RR interval difference (rMSSD) from 23 children diagnosed by ADHD (19 boys and 4 girls), aged 10.5 ± 2.2 years, who were consecutively referred to our outpatient clinic for paediatric cardiology. Eleven children received medication with methylphenidate (MPH), while twelve children were initially examined without medication. Of these, eight probands were re-examined after therapy with MPH was established. Controls comprised 19 children (10 boys, 9 girls) from our Holter ECG data base without any cardiac or circulatory disease. Compared to healthy controls, the ADHD children with and without MPH treatment showed significantly higher mean heart rates (ADHD without MPH: 94.3 ± 2.2; ADHD with MPH: 90.5 ± 1.8, controls: 84.7 ± 1.8). pNN50 (ADHD without MPH: 6.5 ± 2.7; ADHD with MPH: 14.2 ± 6.9, controls: 21.5 ± 9.0) and rMSSD (ADHD without MPH: 26.1 ± 4.1; ADHD with MPH: 36.7 ± 8.3, controls: 44.5 ± 10.1) were lowest in ADHD children without MPH, middle in ADHD children with MPH and highest in controls. SDNN values were not significantly different. The hourly analysis shows highly significant reduced pNN50 and rMSSD values in untreated ADHD children between 5:00 pm and 6:00 am while the pattern approaches to levels of controls during MPH treatment. Data of this pilot study indicate a decreased vagal tone with

  10. Exercise Heart Rate Reserve and Recovery as Predictors of Incident Type 2 Diabetes.

    PubMed

    Jae, Sae Young; Kurl, Sudhir; Laukkanen, Jari A; Zaccardi, Francesco; Choi, Yoon-Ho; Fernhall, Bo; Carnethon, Mercedes; Franklin, Barry A

    2016-05-01

    We tested the hypothesis that selected exercise heart rate responses, specifically those providing indices of autonomic dysfunction, may be associated with incident type 2 diabetes in 2231 apparently healthy men with normal baseline fasting glucose levels. Heart rate reserve was calculated as the difference between the maximal attained heart rate and the supine resting heart rate, whereas heart rate recovery was defined as the maximal heart rate minus the heart rate measured at 2 minutes of recovery after peak or symptom-limited cardiopulmonary exercise testing. Type 2 diabetes was defined as glycated hemoglobin >6.5% or fasting plasma glucose >126 mg/dL at the follow-up examination. During a median follow-up interval of 5 years, 90 of the 2231 men (4.0%) developed type 2 diabetes. The relative risks of incident type 2 diabetes in men within the lowest quartiles of heart rate reserve and heart rate recovery versus men comprising the highest quartiles of heart rate reserve and heart rate recovery were 2.71 (95% confidence interval, 1.20-6.11) and 2.81 (95% confidence interval, 1.36-5.78) after adjusting for potential confounding variables. Each unit increment (1 beat/min) in heart rate reserve and heart rate recovery was associated with a 2% to 3% decreased incidence of type 2 diabetes. Exercise heart rate reserve and recovery predicted incidence of type 2 diabetes in healthy men, suggesting that autonomic dysfunction may be associated with an increased likelihood for the development of this cardiometabolic risk factor. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Electrocardiogram, heart movement and heart rate in the awake gecko (Hemidactylus mabouia).

    PubMed

    Germer, Carina M; Tomaz, Juliana M; Carvalho, Ana F; Bassani, Rosana A; Bassani, José W M

    2015-01-01

    The electrocardiogram (ECG) is the simplest and most effective non-invasive method to assess the electrical activity of the heart and to obtain information on the heart rate (HR) and rhythm. Because information on the HR of very small reptiles (body mass <10 g) is still scarce in the literature, in the present work we describe a procedure for recording the ECG in non-anesthetized geckos (Hemidactylus mabouia, Moreau de Jonnès, 1818) under different conditions, namely manual restraint (MR), spontaneous tonic immobility (TI), and in the non-restrained condition (NR). In the gecko ECG, the P, QRS and T waves were clearly distinguishable. The HR was 2.83 ± 0.02 Hz under MR, which was significantly greater (p < 0.001) than the HR under the TI (1.65 ± 0.09 Hz) and NR (1.60 ± 0.10 Hz) conditions. Spontaneously beating isolated gecko hearts contracted at 0.84 ± 0.03 Hz. The in vitro beating rate was affected in a concentration-dependent fashion by adrenoceptor stimulation with noradrenaline, as well as by the muscarinic cholinergic agonist carbachol, which produced significant positive and negative chronotropic effects, respectively (p < 0.001). To our knowledge, this is the first report on the ECG morphology and HR values in geckos, particularly under TI. The methodology and instrumentation developed here are useful for non-invasive in vivo physiological and pharmacological studies in small reptiles without the need of physical restraint or anesthesia.

  12. The Effect of Exertion on Heart Rate and Rating of Perceived Exertion in Acutely Concussed Individuals.

    PubMed

    Hinds, Andrea; Leddy, John; Freitas, Michael; Czuczman, Natalie; Willer, Barry

    2016-08-01

    Research suggests that one physiological effect of concussion is a disruption in regulation of autonomic nervous system control that affects the balance between parasympathetic and sympathetic output. While changes in heart rate after concussion have been observed, the nature of the heart rate change during progressive exercise has not been well evaluated in acutely symptomatic patients. Additionally, little is known about the relationship between HR and RPE in this population. We compared changes in heart rate and perceived effort during graded treadmill exertion in recently concussed patients to elucidate the effect of brain injury on cardiovascular response to exercise. Resting HR, HR on exercise initiation, and changes in HR and RPE during the Buffalo Concussion Treadmill Test (BCTT) were compared on two test visits: When patients were symptomatic (acute) and after recovery. Results were compared with the test-retest results obtained from a control group consisting of healthy, non-concussed individuals. Patients had a significantly lower HR at onset of exercise when acutely concussed as compared to when recovered and reported greater perceived exertion at every exercise intensity level when symptomatic, despite exercising at lower workloads, than when recovered. Sympathetic response to increased exertion was not affected by concussion - HR increased in response to exercise at a comparable rate in both tests. These differences observed in response to exercise between the first BCTT and follow-up evaluation in initially concussed patients were not present in non-concussed individuals. Our results suggest that during the acute phase after concussion, acutely concussed patients demonstrated an impaired ability to shift from parasympathetic to sympathetic control over heart rate at the onset of exercise. Changes in the autonomic nervous system after concussion may be more complex than previously reported. Continued evaluation of autonomic regulatory effects in the

  13. The Effect of Exertion on Heart Rate and Rating of Perceived Exertion in Acutely Concussed Individuals

    PubMed Central

    Hinds, Andrea; Leddy, John; Freitas, Michael; Czuczman, Natalie; Willer, Barry

    2016-01-01

    Objective Research suggests that one physiological effect of concussion is a disruption in regulation of autonomic nervous system control that affects the balance between parasympathetic and sympathetic output. While changes in heart rate after concussion have been observed, the nature of the heart rate change during progressive exercise has not been well evaluated in acutely symptomatic patients. Additionally, little is known about the relationship between HR and RPE in this population. Methods We compared changes in heart rate and perceived effort during graded treadmill exertion in recently concussed patients to elucidate the effect of brain injury on cardiovascular response to exercise. Resting HR, HR on exercise initiation, and changes in HR and RPE during the Buffalo Concussion Treadmill Test (BCTT) were compared on two test visits: When patients were symptomatic (acute) and after recovery. Results were compared with the test-retest results obtained from a control group consisting of healthy, non-concussed individuals. Results Patients had a significantly lower HR at onset of exercise when acutely concussed as compared to when recovered and reported greater perceived exertion at every exercise intensity level when symptomatic, despite exercising at lower workloads, than when recovered. Sympathetic response to increased exertion was not affected by concussion - HR increased in response to exercise at a comparable rate in both tests. These differences observed in response to exercise between the first BCTT and follow-up evaluation in initially concussed patients were not present in non-concussed individuals. Conclusion Our results suggest that during the acute phase after concussion, acutely concussed patients demonstrated an impaired ability to shift from parasympathetic to sympathetic control over heart rate at the onset of exercise. Changes in the autonomic nervous system after concussion may be more complex than previously reported. Continued evaluation of

  14. U.S. Heart Failure Rates on the Rise

    MedlinePlus

    ... who are at increased risk for heart failure. Cardiovascular disease includes all types of heart disease, high blood ... than one-third of adults (92 million) have cardiovascular disease. In 2014, nearly 808,000 Americans died from ...

  15. Heart Rate and Initial Presentation of Cardiovascular Diseases (Caliber)

    ClinicalTrials.gov

    2013-09-17

    Abdominal Aortic Aneurysm; Coronary Heart Disease NOS; Unheralded Coronary Death; Intracerebral Haemorrhage; Heart Failure; Ischemic Stroke; Myocardial Infarction; Stroke; Peripheral Arterial Disease; Stable Angina Pectoris; Subarachnoid Haemorrhage; Transient Ischemic Attack; Unstable Angina; Cardiac Arrest, Sudden Cardiac Death

  16. Getting to the Heart of the Matter: Written Disclosure, Gender, and Heart Rate

    PubMed Central

    Epstein, Eva M.; Sloan, Denise M.; Marx, Brian P.

    2006-01-01

    Objective The present study examined gender differences in the psychologic and physical symptom changes associated with written disclosure. Methods Male (n = 48) and female (n = 46) college students were assigned to either a written disclosure condition or a control writing condition. Participants in each condition wrote on 3 consecutive days for 20 minutes each session. Heart rate was recorded during each writing session and the narratives were examined for linguistic content. Participants completed measures of psychologic and physical health at baseline and again 1 month later. Results Participants assigned to the written disclosure condition reported significantly greater psychological and physical health benefits at follow up compared with the control group participants. No significant gender differences were found among those participants assigned to the written disclosure condition. Additionally, although heart rate reactivity and changes in the use of words denoting positive emotion, negative emotion, and cognitive appraisal significantly differed between the writing conditions, no significant gender differences in these variables were found among individuals assigned to the written disclosure condition. Conclusions Written disclosure is associated with significant improvements in both psychologic and physical health for men and women. There was no support for the notion that men may derive greater benefits than women from written disclosure. Furthermore, the results of this study indicate that changes in physiological reactivity and word use associated with written disclosure do not differ between men and women. PMID:15911904

  17. Alterations in the heart rate and activity rhythms of three orbital astronauts on a space mission.

    PubMed

    Liu, Zhizhen; Wan, Yufeng; Zhang, Lin; Tian, Yu; Lv, Ke; Li, Yinghui; Wang, Chunhui; Chen, Xiaoping; Chen, Shanguang; Guo, Jinhu

    2015-01-01

    Environmental factors in space are dramatically different from those on Earth. The spaceflight environment has been known to influence human physiology and behavior on orbital missions. In this study, we investigated alterations in the diurnal rhythms of activity and heart rate of three Chinese astronauts on a space mission. An analysis of the heart rate data showed a significant decrease in heart rate amplitudes during flight in all three subjects. The heart rate amplitudes of all the three astronauts were significantly dampened during flight, and the minimum as well as the maximum value of heart rate increased after flight. A phase shift in heart rate was observed in one of the three astronauts after flight. These results demonstrate the influence of spaceflight on heart physiology and function. In addition, a significant decrease in body trunk activity and rhythmicity occurred during flight, demonstrating that the spaceflight environment disturbs motion adaptation and diurnal activity rhythms.

  18. Alterations in the heart rate and activity rhythms of three orbital astronauts on a space mission

    NASA Astrophysics Data System (ADS)

    Liu, Zhizhen; Wan, Yufeng; Zhang, Lin; Tian, Yu; Lv, Ke; Li, Yinghui; Wang, Chunhui; Chen, Xiaoping; Chen, Shanguang; Guo, Jinhu

    2015-01-01

    Environmental factors in space are dramatically different from those on Earth. The spaceflight environment has been known to influence human physiology and behavior on orbital missions. In this study, we investigated alterations in the diurnal rhythms of activity and heart rate of three Chinese astronauts on a space mission. An analysis of the heart rate data showed a significant decrease in heart rate amplitudes during flight in all three subjects. The heart rate amplitudes of all the three astronauts were significantly dampened during flight, and the minimum as well as the maximum value of heart rate increased after flight. A phase shift in heart rate was observed in one of the three astronauts after flight. These results demonstrate the influence of spaceflight on heart physiology and function. In addition, a significant decrease in body trunk activity and rhythmicity occurred during flight, demonstrating that the spaceflight environment disturbs motion adaptation and diurnal activity rhythms.

  19. Design of an FECG scalp electrode fetal heart rate monitor.

    PubMed

    Reguig, F B; Kirk, D L

    1996-03-01

    The design of a fetal heart rate (FHR) monitor using fetal electrocardiogram (FECG) scalp electrodes is described. It is shown that the design approach followed two stages: generation of FHR pulses at R-R intervals and FHR computation. The former uses a simple hardware approach for QRS detection and R-wave enhancement, while the latter requires a software implementation in order to produce FHR traces on a beat to beat basis. The QRS detection is based on bandpass filtering using switched mode capacitor technique; the R-wave enhancement and amplitude information are achieved by differentiation followed by fullwave rectification and peak detection. An adaptive threshold together with a comparator circuit are used to generate FHR pulses at R-R intervals. Beat to beat variations of FHR traces are produced by hardware and software implementation on a Z80 microprocessor board. Results obtained by the FHR monitor are evaluated and contrasted to other commercial FHR monitors.

  20. Heart rate variability monitoring and assessment system on chip.

    PubMed

    Massagram, Wansuree; Boric-Lubecke, Olga; Macchiarulo, Luca; Chen, Mingqi

    2005-01-01

    This paper describes a system on a chip for heart rate variability monitoring and assessment. The system design applies digital techniques to measure RR intervals from ECG signals, then categorizes and stores HRV measures in an internal memory. The system has been tested for functionality, synthesized and laid out in a 0.5 μm CMOS technology in a 3x3 mm2chip with less than 1.5 μW power dissipation. The chip detects all R peaks with millisecond accuracy after the initial 2 seconds of data, and stores up to 2 minutes of continuous ECG data and up to 4 minutes of HRV histogram. Compact size, low cost, and low power consumption make this chip suitable for employment in modern implantable and portable devices.

  1. Heart rate variability in kittens during early postnatal ontogeny.

    PubMed

    Fateev, M M; Nikolaeva, T N; Dashichev, K V; Olendar, N V

    2009-06-01

    Heart rate variability in awake kittens under resting conditions was studied during the following periods of postnatal ontogeny: newborn animals, 10-day-old animals (eye opening), 20-day-old animals (rise on the legs), and 30-day-old animals (control). Newborn animals were characterized by high activity of the sympathoadrenal system due to birth stress. The effect of stress factors increased in 10-day-old kittens, which was related to the start of functioning of distant receptors and delivery of new environmental information into the brain. The acquisition of upright posture and locomotion on the limbs were accompanied by activation of the vagus nerve in kittens. Significant changes in temporal, geometric, and spectral characteristics illustrate an increase in adaptability of the organism and possibility for independent living (particularly, by the 30th day of life).

  2. Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots

    SciTech Connect

    Georgieva, A. E.; Payne, S. J.; Moulden, M.; Redman, C. W. G.

    2010-10-25

    Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced 'modified' Sensitivity (SE deg.) and 'modified' Positive Predictive Value (PPV deg.) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

  3. Correlated and uncorrelated heart rate fluctuations during relaxing visualization

    NASA Astrophysics Data System (ADS)

    Papasimakis, N.; Pallikari, F.

    2010-05-01

    The heart rate variability (HRV) of healthy subjects practicing relaxing visualization is studied by use of three multiscale analysis techniques: the detrended fluctuation analysis (DFA), the entropy in natural time (ENT) and the average wavelet (AWC) coefficient. The scaling exponent of normal interbeat interval increments exhibits characteristics of the presence of long-range correlations. During relaxing visualization the HRV dynamics change in the sense that two new features emerge independent of each other: a respiration-induced periodicity that often dominates the HRV at short scales (<40 interbeat intervals) and the decrease of the scaling exponent at longer scales (40-512 interbeat intervals). In certain cases, the scaling exponent during relaxing visualization indicates the breakdown of long-range correlations. These characteristics have been previously seen in the HRV dynamics during non-REM sleep.

  4. Tracking driver's heart rate by continuous-wave Doppler radar.

    PubMed

    Kwang Jin Lee; Chanki Park; Boreom Lee

    2016-08-01

    Developing driving safety system with medical assistance devices for preventing accidents has become a major social issue in recent year. These devices have been developed using electrocardiogram (ECG) and photoplethysmogram (PPG) for measuring the heart rate (HR). However, driver should directly contact with the sensor for monitoring the HR. Recently, non-contact system based on continuous-wave Doppler radar has widely studied for monitoring HR. The periodogram by Fast Fourier Transform (FFT) was used for estimating HR. However, if motion artifacts by movement of driver and vehicle vibration contaminate the radar signal, we cannot find spectral peak of HR using FFT. In this paper, we propose a method using multiple signal classification (MUSIC) for estimating HR. We compared MUSIC algorithms with a commonly used FFT method using real experiment data while driving. The results indicate that our proposed method can estimate HR accurately from received radar Doppler signal with motion artifacts.

  5. Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots

    NASA Astrophysics Data System (ADS)

    Georgieva, A. E.; Payne, S. J.; Moulden, M.; Redman, C. W. G.

    2010-10-01

    Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced `modified' Sensitivity (SE°) and `modified' Positive Predictive Value (PPV°) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

  6. Heart rate, startle response, and intrusive trauma memories

    PubMed Central

    Chou, Chia-Ying; Marca, Roberto La; Steptoe, Andrew; Brewin, Chris R

    2014-01-01

    The current study adopted the trauma film paradigm to examine potential moderators affecting heart rate (HR) as an indicator of peritraumatic psychological states and as a predictor of intrusive memories. We replicated previous findings that perifilm HR decreases predicted the development of intrusive images and further showed this effect to be specific to images rather than thoughts, and to detail rather than gist recognition memory. Moreover, a group of individuals showing both an atypical sudden reduction in HR after a startle stimulus and higher trait dissociation was identified. Only among these individuals was lower perifilm HR found to indicate higher state dissociation, fear, and anxiety, along with reduced vividness of intrusions. The current findings emphasize how peritraumatic physiological responses relate to emotional reactions and intrusive memory. The moderating role of individual difference in stress defense style was highlighted. PMID:24397333

  7. Robust estimation of fetal heart rate variability using Doppler ultrasound.

    PubMed

    Fernando, Kumari L; Mathews, V John; Varner, Michael W; Clark, Edward B

    2003-08-01

    This paper presents a new measure of heart rate variability (HRV) that can be estimated using Doppler ultrasound techniques and is robust to variations in the angle of incidence of the ultrasound beam and the measurement noise. This measure employs the multiple signal characterization (MUSIC) algorithm which is a high-resolution method for estimating the frequencies of sinusoidal signals embedded in white noise from short-duration measurements. We show that the product of the square-root of the estimated signal-to-noise ratio (SNR) and the mean-square error of the frequency estimates is independent of the noise level in the signal. Since varying angles of incidence effectively changes the input SNR, this measure of HRV is robust to the input noise as well as the angle of incidence. This paper includes the results of analyzing synthetic and real Doppler ultrasound data that demonstrates the usefulness of the new measure in HRV analysis.

  8. Heart Rate Variability Dynamics for the Prognosis of Cardiovascular Risk

    PubMed Central

    Ramirez-Villegas, Juan F.; Lam-Espinosa, Eric; Ramirez-Moreno, David F.; Calvo-Echeverry, Paulo C.; Agredo-Rodriguez, Wilfredo

    2011-01-01

    Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis. PMID:21386966

  9. The role of heart rate variability in sports physiology.

    PubMed

    Dong, Jin-Guo

    2016-05-01

    Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology.

  10. Enkephalin inhibits vagal control of heart rate, contractile force and coronary blood flow in the canine heart in vivo.

    PubMed

    Caffrey, J L

    1999-05-28

    The following studies were conducted to determine if the ability of the intrinsic cardiac opioid, met-enkephalin-arg-phe to interrupt vagal bradycardia can be generalized to include the disruption of vagal effects on atrial contraction and coronary blood flow. Anesthetized dogs were instrumented to measure heart rate and left atrial contractile force or heart rate and coronary blood flow. The response of each variable was recorded at rest and during vagal stimulation. During the evaluation of vagal effects on contractile activity and coronary blood flow, heart rate was maintained constant by electrically pacing the hearts above their resting heart rate. In the first protocol, vagal stimulation reduced both heart rate and atrial contractile force in a frequency dependent fashion. When met-enkephalin-arg-phe (MEAP) was infused systemically for three min at 3 nmol min(-1) kg(-1), there were no observed changes in resting heart rate or atrial contraction. However, when the vagal stimuli were reapplied during the peptide infusion, the previously observed vagal effects on rate and contractile force were reduced in magnitude by one-half to two-thirds. The ability of MEAP to interrupt the vagal control of heart rate and contractile activity involves opiate receptors since the effect was eliminated in both cases by prior opiate receptor blockade with the high affinity antagonist, diprenorphine. In the second protocol, vagal stimulation produced a transient increase in coronary blood flow and an accompanying increase in myocardial oxygen consumption. These effects were reduced by approximately 80% during the systemic infusion of MEAP. A similar increase in coronary blood flow mediated by the direct acting muscarinic agonist, methacholine, was unaltered by the infusion of peptide. In summary, these data suggest that the intrinsic cardiac enkephalin, MEAP, is capable of inhibiting the vagal control of heart rate, contractile force and coronary blood flow and probably does so

  11. Running demands and heart rate response in rugby sevens referees.

    PubMed

    Suarez-Arrones, Luis; Calvo-Lluch, África; Portillo, Javier; Sánchez, Francisco; Mendez-Villanueva, Alberto

    2013-06-01

    The purpose of this study was to examine for the first time the match running demands and heart rate (HR) responses associated with elite rugby sevens referees. Twelve referees were analyzed over 38 games, using Global Positioning System. Referees covered an average distance of 1665.2 ± 203.5 m per game (15.1 ± 0.5 minutes). Over this distance, 22.3% (371.8 ± 48.9 m) was spent standing and walking, 25.9% (431.2 ± 92.6 m) jogging, 12.4% (206.5 ± 53.2 m) cruising, 23.8% (395.6 ± 94.3 m) striding, 8% (133.3 ± 61.6 m) high-intensity running, and 7.6% (126.7 ± 87.3 m) sprinting. The average maximal distance of sprints, the number of sprints, and the mean sprint distance over the game were 31.3 ± 13.4 m, 5.76 ± 3.6 sprints, and 19.9 ± 7.8 m, respectively. The referee's work-to-rest ratio was 3.5:1. There were no statistical differences between the first and second half in any of the running variables analyzed. The average HR in the second half (160 ± 9 b·min(-1); 86 ± 5% maximal heart rate (HRmax) of the estimated) was higher (p < 0.05) than the HR recorded in the first half (154 ± 11 b·min(-1); 83 ± 6% of the estimated HRmax). This study also suggests that the physical demands of referring in rugby sevens are quite different from those encountered in other rugby codes, and the training regimes need to meet the increased overall running demands and high-intensity running activity.

  12. Fetal magnetocardiography: time intervals and heart rate variability.

    PubMed

    Van Leeuwen, P

    2004-11-30

    Biomagnetism in the perinatal domain has been dominated by fetal cardiology, and early work pointed out the potential of both fetal cardiac time intervals (CTI) and heart rate variability (HRV) for future clinical applications. Recent improvements in instrumentation have permitted numerous groups to investigate a substantial number of healthy fetuses in these two areas and to lay the groundwork for a delineation of normal ranges. With respect to fetal CTI it is now clear that in particular the duration of P wave, PR interval and QRS complex reflect fetal growth and development. Preliminary studies have shown that the age-adjusted CTI are shorter in growth-retarded fetuses and altered in ca