WorldWideScience
 
 
1

Conclusion  

International Nuclear Information System (INIS)

Author come to conclusion that received systematic data let estimate the geochemical background of sediments layers of depression of Tajikistan on bismuth, indium and thallium and other elements and also can be used at estimation of balance of chemical elements in Earth crust, at searching works in the region, at solving of ecology problems

2006-01-01

2

Conclusion  

International Nuclear Information System (INIS)

[en] In this chapter of book are present conclusions about work done by author, in particular that he found comparatively simple and available ways of synthesis of glycerin of acetylene line and glycerin of ethylen line which before was unknown or almost unknown in the chemical literature

1961-01-01

3

HEART RATE MEASURING DEVICE  

UK PubMed Central (United Kingdom)

The invention relates to a heart rate measuring apparatus and a method, adapted for measuring a subject's (6) heart rate and/or heart rate variation. The heart rate measuring apparatus (1) comprises a holder (2) adapted for carrying a portion of a body part of the subject (6) lying on or resting against the holder (2), a motion sensor (4) operatively connected to the holder (2), wherein the holder (2) is adapted for being at least partly moveable in a horizontal direction relative to the ground (7), the motion sensor (4) being adapted for measuring a signal generated by a movement of the subject (6) at least partly in the horizontal direction. In this way, a reliable signal is obtained adapted for measuring the heart rate and/or heart rate variation of a subject while keeping the implementation costs low.

AARTS RONALDUS MARIA; BAMBANG OETOMO SIDARTO

4

HEART RATE VARIABILITY MEASUREMENT METHOD  

UK PubMed Central (United Kingdom)

A heart rate variability measurement method is revealed. The method includes the following steps. At first, play a piece of music for a participant. Then detect a change in vascular volume of the participant. Next depict a continuous waveform signal of the change in vascular volume. Thus while measuring the heart rate as well as heart rate variability, the participant is not easy to get nervous or impatient and the real heart rate as well as heart rate variability can be obtained, without being affected by the mood. Therefore, the accuracy of the heart rate variability during measurement is increased.

HU WEI-CHIH; CHANG CHAO-FENG

5

Nonlinear fetus heart rate tester  

UK PubMed Central (United Kingdom)

Disclosed is a nonlinear fetus heart rate tester, belonging to the technical field of the medical health care. The device adopts a supersonic Doppler sensor to extract out the fetal heart sound signal, then a fetal heart rate signal extractor extracts out the envelope of the sound frequency signal from the sound frequency signal of the fetal heart sound, the square signal obtained by the fetal heart rate signal extractor is transferred to a PC6360 analog/digit interface card to finish the analog/digit conversion of the fetal heart rate signal and is transferred to a nonlinear computer analysis processor, and the instantaneous fetal heart rate is computed according to the time interval of the adjacent twice square waves to finish the real-time display and recurrence of the data and patterns of the fetal heart rate signal and the storage of the data. Doctors can work out the diagnostic proposals to advise the clinic and family planning and raise the population quality according to the corresponding relation of the different distribution regions of the nonlinear characteristic quantity and the different fetuses' health conditions. The utility model has low price and good market outlook, which can extended in the hospitals that are higher than the county level and the teaching and scientific research fields of the clinical medicine of the colleges and universities at the whole country, and the economic benefit and the social benefit have obviously positive effects.

XIAO QING LIU

6

HEART RATE MONITOR FOR SWIMMERS  

UK PubMed Central (United Kingdom)

There provided a heart rate monitor that includes a pair of electrodes, a program control panel having a power supply, a vibration feedback module for advising the user when predetermined heart rates have been reached, and a data retrieval member. The electrodes are arranged to be in contact with the swimmer's body and connected to a microcontroller in program control panel. The program control panel has a plurality of heart rate selection members that provide a signal for sending to the swimmer when the predetermined heart rate has been reached. When the predetermined heart rate is reached, the signal is sent to a vibration feedback module. Another aspect of the present invention is to log heart rate data and swimming duration.; This is accomplished by providing the program control panel with blue tooth zone selectors that export data from the program control panel and imports the data to a hand held computer. There are several embodiments of the heart rate monitor described, each of which uses various aspects of a swimsuit depending upon the style and convenience desired by the user.

MCDONOUGH DANIEL K

7

Heart rate changes during electroconvulsive therapy.  

UK PubMed Central (United Kingdom)

BACKGROUND: This observational study documented heart rate over the entire course of electrically induced seizures and aimed to evaluate the effects of stimulus electrode placement, patients' age, stimulus dose, and additional predictors. METHOD: In 119 consecutive patients with 64 right unilateral (RUL) and 55 bifrontal (BF) electroconvulsive treatments, heart rate graphs based on beat-to-beat measurements were plotted up to durations of 130 s. RESULTS: In RUL stimulation, the initial drop in heart rate lasted for 12.5 ± 2.6 s (mean ± standard deviation). This depended on stimulus train duration, age, and baseline heart rate. In seizures induced with BF electrode placement, a sympathetic response was observed within the first few seconds of the stimulation phase (median 3.5 s). This was also the case with subconvulsive stimulations. The mean peak heart rate in all 119 treatments amounted to 135 ± 20 bpm and depended on baseline heart rate and seizure duration; electrode placement, charge dose, and age were insignificant in regression analysis. A marked decline in heart rate in connection with seizure cessation occurred in 71% of treatments. CONCLUSIONS: A significant independent effect of stimulus electrode positioning on cardiac action was evident only in the initial phase of the seizures. Electrical stimulation rather than the seizure causes the initial heart rate increase in BF treatments. The data reveal no rationale for setting the stimulus doses as a function of intraictal peak heart rates ('benchmark method'). The marked decline in heart rate at the end of most seizures is probably mediated by a baroreceptor reflex.

Nagler J

2013-01-01

8

Association between heart rate variability and manual pulse rate.  

UK PubMed Central (United Kingdom)

INTRODUCTION: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Hart J

2013-09-01

9

Heart rate in professional musicians  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract 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.

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

2008-01-01

10

HCN Channels and Heart Rate  

Directory of Open Access Journals (Sweden)

Full Text Available Hyperpolarization and Cyclic Nucleotide (HCN) -gated channels represent the molecular correlates of the “funny” pacemaker current (If), a current activated by hyperpolarization and considered able to influence the sinus node function in generating cardiac impulses. HCN channels are a family of six transmembrane domain, single pore-loop, hyperpolarization activated, non-selective cation channels. This channel family comprises four members: HCN1-4, but there is a general agreement to consider HCN4 as the main isoform able to control heart rate. This review aims to summarize advanced insights into the structure, function and cellular regulation of HCN channels in order to better understand the role of such channels in regulating heart rate and heart function in normal and pathological conditions. Therefore, we evaluated the possible therapeutic application of the selective HCN channels blockers in heart rate control.

Pietro Scicchitano; Santa Carbonara; Gabriella Ricci; Cosimo Mandurino; Manuela Locorotondo; Gabriella Bulzis; Michele Gesualdo; Annapaola Zito; Rosa Carbonara; Ilaria Dentamaro; Graziano Riccioni; Marco Matteo Ciccone

2012-01-01

11

Fetal Heart Rate Monitoring during Labor  

Science.gov (United States)

... Why is fetal heart rate monitoring done during labor and delivery? Fetal heart rate monitoring may help ... Why is fetal heart rate monitoring done during labor and delivery? • What are the types of monitoring? • ...

12

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

UK PubMed Central (United Kingdom)

AIM: To measure the effect of sound and whole-body vibration on infants' heart rate and heart rate variability during ground and air ambulance transport. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Karlsson BM; Lindkvist M; Lindkvist M; Karlsson M; Lundström R; Håkansson S; Wiklund U; van den Berg J

2012-02-01

13

Heart rate and heart failure: the role of ivabradine therapy.  

UK PubMed Central (United Kingdom)

PURPOSE OF REVIEW: The clinical data about the impact of heart rate reduction in heart failure therapy will be reviewed. RECENT FINDINGS: Clinical and experimental studies showed an association between elevated resting heart rate and mortality risk in heart failure patients. This review summarizes that heart rate level at rest and its extent of reduction is a sensitive indicator for outcome in heart failure. In addition to the nonspecific heart rate reducing drugs like ?-blockers, cardiac glycosides and Ca(2+) antagonists, ivabradine is a highly selective heart rate reducing agent without modifying ventricular contractility and atrioventricular conduction in humans and animals, and has recently been shown to improve cardiovascular outcomes in patients with systolic heart failure by lowering the heart rate only. The present and future role of heart rate reduction in the spectrum of heart failure disease and therapy will be outlined and evaluated. SUMMARY: Elevated heart rate at rest represents a key indicator of adverse outcome in heart failure and implies a major treatment target in these patients.

Reil JC; Böhm M

2013-05-01

14

[Resting heart rate and cardiovascular disease.  

UK PubMed Central (United Kingdom)

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.

Brito Díaz B; Alemán Sánchez JJ; Cabrera de León A

2013-08-01

15

Heart rate recovery after exercise: relations to heart rate variability and complexity  

Directory of Open Access Journals (Sweden)

Full Text Available Physical exercise is associated with parasympathetic withdrawal and increased sympathetic activity resulting in heart rate increase. The rate of post-exercise cardiodeceleration is used as an index of cardiac vagal reactivation. Analysis of heart rate variability (HRV) and complexity can provide useful information about autonomic control of the cardiovascular system. The aim of the present study was to ascertain the association between heart rate decrease after exercise and HRV parameters. Heart rate was monitored in 17 healthy male subjects (mean age: 20 years) during the pre-exercise phase (25 min supine, 5 min standing), during exercise (8 min of the step test with an ascending frequency corresponding to 70% of individual maximal power output) and during the recovery phase (30 min supine). HRV analysis in the time and frequency domains and evaluation of a newly developed complexity measure - sample entropy - were performed on selected segments of heart rate time series. During recovery, heart rate decreased gradually but did not attain pre-exercise values within 30 min after exercise. On the other hand, HRV gradually increased, but did not regain rest values during the study period. Heart rate complexity was slightly reduced after exercise and attained rest values after 30-min recovery. The rate of cardiodeceleration did not correlate with pre-exercise HRV parameters, but positively correlated with HRV measures and sample entropy obtained from the early phases of recovery. In conclusion, the cardiodeceleration rate is independent of HRV measures during the rest period but it is related to early post-exercise recovery HRV measures, confirming a parasympathetic contribution to this phase.

M. Javorka; I. Zila; T. Balhárek; K. Javorka

2002-01-01

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Influence of heart failure severity on heart rate variability  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. Autonomic regulation of cardiovascular functions in congestive heart failure is characterised by enhanced sympathetic and diminished parasympathetic activity. The long term predominance of sympathetic tone is a significant factor in arrhythmogenesis, sudden cardiac death, and progressive pump failure. Heart rate variability (HRV) is a noninvasive method for estimating the sympatho vagal balance in cardiovascular control. Aim. The aim of this study was to analyse the influence of heart failure severity on HRV. Method. HRV was estimated through the spectral analysis of short term ECG (Cardiovit AT 60, Schiller, CH) in 63 patients (78% male, mean age 56.9±10.9 years) and 14 healthy volunteers (57.1% male, mean age 53.1±8.2 years). The following spectral components were measured: VLF (very low frequency), LF (low frequency), HF (high frequency), and total power (Tot Power). Results. All spectral components were statistically, significantly lower in patients with heart failure in comparison to healthy controls (VLF: 159.89±147.02 vs. 285.50±202.77 ms2; p=0.023, LF: 161.48±204.01 vs. 474.57±362.93 ms2; p<0.001, HF: 88.58±102.47 vs. 362.71±318.28 ms2; p<0.001), as well as total power (Tot Power: 723.39±644.52 vs. 1807.29±1204.74 ms2; p<0.001). A significant, negative correlation between HRV parameters and NYHA class was detected in heart failure patients (VLF: r=-0.391; p=0.002, LF: r=-0.401; p=0.001, and Tot Power r=-0.372; p=0.003). Ejection fraction proved to be in significant, positive correlation to VLF (r=0.541; p=0.002), LF (r=0.531; p=0.003), HF (r=0.418; p=0.020), and Tot Power (r=0.457; p=0.013). Conclusion. Significant HRV reduction is a precursor to incipient heart failure (NYHA I). In heart failure progression, total power as well as the power of all spectral components is progressively reduced. LF and Tot Power are the most prominent parameters for discriminating between the different stages of heart failure. These results could promote HRV as an important decision-making tool in heart failure treatment as well as in monitoring the results of that treatment.

Zamaklar-Trifunovi? Danijela; Seferovi? Petar M.; Živkovi? Mirjana; Jeli? Vera; Vukomanovi? Goran; Petrovi? Milan; Mili? Nataša; Risti? Arsen D.; Simeunovi? Dejan

2005-01-01

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Acute alcohol ingestion reduces heart rate variability.  

UK PubMed Central (United Kingdom)

Blood pressure, heart rate and heart rate variability (HRV) prior and during acute ethanol intoxication (0.7 g/kg) were studied in 8 healthy volunteers. Blood pressure and heart rate remained unaltered during intoxication. While HRV was significantly reduced immediately after ingestion (2P = 0.01). It is speculated that the reduction of HRV after heavy ethanol consumption contributes to the genesis of cardiac arrhythmias in chronic alcoholics with or without clinical evidence of heart disease.

Weise F; Krell D; Brinkhoff N

1986-05-01

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Assessing resting heart rate in adolescents: determinants and correlates.  

Science.gov (United States)

The aim of this study was to evaluate the distribution of resting heart rate and its biological and environmental determinants in adolescents. The study was cross- sectional and the population consisted of 2230 children and adolescents, age range 12-18 years, enrolled randomly from state schools in Turin, Italy. In all participants the following parameters were evaluated: heart rate, blood pressure (BP), weight, height, degree of sexual development, physical activity, parental socio-cultural level. Heart rate and BP were measured after 5, 10 and 15 min in a sitting position. Furthermore, to obtain regression equations to define heart rate as a function of the other variables available, a multiple regression analysis was performed. In both sexes BP, but not heart rate, declined significantly from the first to the last determination. Heart rate was positively and significantly correlated to BP level in both sexes; heart rate was higher in girls (3 bpm) and followed a progressive decreasing trend with age in both sexes, that was opposite to BP values. Age, sexual maturation, height, physical activity and parental socio-cultural level were independent determinants of resting heart rate. In conclusion, resting heart rate in adolescents is related to several methodological, constitutional and environmental factors that have to be taken into account when assessing heart rate values and constructing tables of normal values. PMID:12082493

Rabbia, F; Grosso, T; Cat Genova, G; Conterno, A; De Vito, B; Mulatero, P; Chiandussi, L; Veglio, F

2002-05-01

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Assessing resting heart rate in adolescents: determinants and correlates.  

UK PubMed Central (United Kingdom)

The aim of this study was to evaluate the distribution of resting heart rate and its biological and environmental determinants in adolescents. The study was cross- sectional and the population consisted of 2230 children and adolescents, age range 12-18 years, enrolled randomly from state schools in Turin, Italy. In all participants the following parameters were evaluated: heart rate, blood pressure (BP), weight, height, degree of sexual development, physical activity, parental socio-cultural level. Heart rate and BP were measured after 5, 10 and 15 min in a sitting position. Furthermore, to obtain regression equations to define heart rate as a function of the other variables available, a multiple regression analysis was performed. In both sexes BP, but not heart rate, declined significantly from the first to the last determination. Heart rate was positively and significantly correlated to BP level in both sexes; heart rate was higher in girls (3 bpm) and followed a progressive decreasing trend with age in both sexes, that was opposite to BP values. Age, sexual maturation, height, physical activity and parental socio-cultural level were independent determinants of resting heart rate. In conclusion, resting heart rate in adolescents is related to several methodological, constitutional and environmental factors that have to be taken into account when assessing heart rate values and constructing tables of normal values.

Rabbia F; Grosso T; Cat Genova G; Conterno A; De Vito B; Mulatero P; Chiandussi L; Veglio F

2002-05-01

20

Resting heart rate and the risk of heart failure in healthy adults: the Rotterdam Study.  

UK PubMed Central (United Kingdom)

BACKGROUND: An elevated resting heart rate is associated with rehospitalization for heart failure and is a modifiable risk factor in heart failure patients. We aimed to examine the association between resting heart rate and incident heart failure in a population-based cohort study of healthy adults without pre-existing overt heart disease. METHODS AND RESULTS: We studied 4768 men and women aged ?55 years from the population-based Rotterdam Study. We excluded participants with prevalent heart failure, coronary heart disease, pacemaker, atrial fibrillation, atrioventricular block, and those using ?-blockers or calcium channel blockers. We used extended Cox models allowing for time-dependent variation of resting heart rate along follow-up. During a median of 14.6 years of follow-up, 656 participants developed heart failure. The risk of heart failure was higher in men with higher resting heart rate. For each increment of 10 beats per minute, the multivariable adjusted hazard ratios in men were 1.16 (95% confidence interval, 1.05-1.28; P=0.005) in the time-fixed heart rate model and 1.13 (95% confidence interval, 1.02-1.25; P=0.017) in the time-dependent heart rate model. The association could not be demonstrated in women (P for interaction=0.004). Censoring participants for incident coronary heart disease or using time-dependent models to account for the use of ?-blockers or calcium channel blockers during follow-up did not alter the results. CONCLUSIONS: Baseline or persistent higher resting heart rate is an independent risk factor for the development of heart failure in healthy older men in the general population.

Nanchen D; Leening MJ; Locatelli I; Cornuz J; Kors JA; Heeringa J; Deckers JW; Hofman A; Franco OH; Stricker BH; Witteman JC; Dehghan A

2013-05-01

 
 
 
 
21

Heart Rate Turbulence: a Review  

Directory of Open Access Journals (Sweden)

Full Text Available Heart rate turbulence (HRT) is a recently coined phrase that describes the short term fluctuation in sinus cycle length that follows a ventricular premature complex (VPC). Its proven clinical significance lies in its ability to predict mortality and sudden cardiac death following myocardial infarction, although small studies suggest that it is also applicable to many other cardiac diseases. This review will attempt to summarize the literature to date, and to speculate on possible mechanisms. Because HRT is a new field, there are only a handful of full length papers on it. In order to present the full breadth of the research being carried out, the information provided here is based on conference abstracts as well as peer reviewed articles, and readers should keep this in mind. Most of the literature cited here, and downloadable HRT calculation programs (in C++) are available on the website www.h-r-t.org.

Mari A. Watanabe

2003-01-01

22

Heart rate variability in healthy population  

International Nuclear Information System (INIS)

Background: Heart rate variability has been considered as an indicator of autonomic status. Little work has been done on heart rate variability in normal healthy volunteers. We aimed at evolving the reference values of heart rate variability in our healthy population. Methods: Twenty-four hour holter monitoring of 37 healthy individuals was done using Holter ECG recorder 'Life card CF' from 'Reynolds Medical'. Heart rate variability in both time and frequency domains was analysed with 'Reynolds Medical Pathfinder Digital/700'. Results: The heart rate variability in normal healthy volunteers of our population was found in time domain using standard deviation of R-R intervals (SDNN), standard deviation of average NN intervals (SDANN), and Square root of the mean squared differences of successive NN intervals (RMSSD). Variation in heart rate variability indices was observed between local and foreign volunteers and RMSSD was found significantly increased (p

2010-01-01

23

Heart Rate Control Via Vagus Nerve Stimulation.  

Science.gov (United States)

Objectives.? There is ample and well-established evidence that direct electrical stimulation of the vagus nerve can change heart rate in animals and humans. Since tachyarrhythmias cannot always be controlled through medication, we sought, in this pilot study, to elucidate whether a clinical implantable lead system that is used in cervical vagus nerve stimulation therapy (VNS therapy) also can be used for control of heart rate, and tachycardia in particular. Materials and Methods.? Experiments were carried out in three pigs (weight 21-26 kg) under general anesthesia. The right and left vagus nerves in the neck region were exposed by dissection, and bipolar, multiturn, helical, silicone leads were wrapped around the vagus nerves. Stimulation was applied by an external device with multivariable settings: frequency 10-100 Hz, pulse duration 100-700 µsec; delay 0-0.5 msec; current 0.5-14 mA. Measurements were performed under normal sinus rhythm (RR-interval 501 ± 30 msec) and during isoprenaline-induced tachycardia (RR-interval 284 ± 11 msec). Results.? VNS, under optimal pacing conditions (100 Hz; 5 mA; 0.2 msec; 70 msec delay), in an electrocardiogram-triggered (ECG-triggered) pacing mode, increased RR-intervals by approximately 40%, irrespective of the duration of the RR-interval preceding VNS. The maximum effect on heart rate was established within approximately 5 sec after the onset of stimulation and was reversible and reproducible. No differences were found between stimulation of the right or left vagus nerve. Conclusion.? VNS can be used effectively and rapidly to decrease heart rate, in acute settings, when connected to an external pacing system. Future devices that are fully implantable may be used for nonpharmacological treatment of illnesses in which tachycardia results in deterioration of cardiac function. PMID:22151709

Buschman, Hendrik P; Storm, Corstiaan J; Duncker, Dirk J; Verdouw, Pieter D; van der Aa, Hans E; van der Kemp, Peter

2006-07-01

24

Influence of blood glucose on heart rate and cardiac autonomic function. The DESIR study.  

UK PubMed Central (United Kingdom)

OBJECTIVES: ? To evaluate in a general population, the relationships between dysglycaemia, insulin resistance and metabolic variables, and heart rate, heart rate recovery and heart rate variability. METHODS: ? Four hundred and forty-seven participants in the Data from an Epidemiological Study on the Insulin Resistance syndrome (DESIR) study were classified according to glycaemic status over the preceding 9 years. All were free of self-reported cardiac antecedents and were not taking drugs which alter heart rate. During five consecutive periods: rest, deep breathing, recovery, rest and lying to standing, heart rate and heart rate varability were evaluated and compared by ANCOVA and trend tests across glycaemic classes. Spearman correlation coefficients quantified the relations between cardio-metabolic risk factors, heart rate and heart rate varability. RESULTS: ? Heart rate differed between glycaemic groups, except during deep breathing. Between rest and deep-breathing periods, patients with diabetes had a lower increase in heart rate than others (P(trend) < 0.01); between deep breathing and recovery, the heart rate of patients with diabetes continued to increase, for others, heart rate decreased (P(trend) < 0.009). Heart rate was correlated with capillary glucose and triglycerides during the five test periods. Heart rate variability differed according to glycaemic status, especially during the recovery period. After age, sex and BMI adjustment, heart rate variability was correlated with triglycerides at two test periods. Change in heart rate between recovery and deep breathing was negatively correlated with heart rate variability at rest, (r=-0.113, P < 0.05): lower resting heart rate variability was associated with heart rate acceleration. CONCLUSIONS: ? Heart rate, but not heart rate variability, was associated with glycaemic status and capillary glucose. After deep breathing, heart rate recovery was altered in patients with known diabetes and was associated with reduced heart rate variability. Being overweight was a major correlate of heart rate variability.

Valensi P; Extramiana F; Lange C; Cailleau M; Haggui A; Maison Blanche P; Tichet J; Balkau B

2011-04-01

25

What is the “normal” fetal heart rate?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Aim. There is no consensus about the normal fetal heart rate. Current international guidelines recommend for the normal fetal heart rate (FHR) baseline different ranges of 110 to 150 beats per minute (bpm) or 110 to 160 bpm. We started with a precise definition of “normality” and performed a retrosp...

Stephanie Pildner von Steinburg; Anne-Laure Boulesteix; Christian Lederer; Stefani Grunow; Sven Schiermeier; Wolfgang Hatzmann

26

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

Directory of Open Access Journals (Sweden)

Full Text Available Background: 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. Aims: The goal of this study was to demonstrate heart rate and heart rate variability analysis for the first time during Tai Chi and jogging. Volunteers and Methods: 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. Results: 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. Conclusions: 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.

Gerhard Litscher; Weibo Zhang; Tao Huang; Lu Wang

2011-01-01

27

Ear Acupressure, Heart Rate, and Heart Rate Variability in Patients with Insomnia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This high-tech “teleacupuncture study” describes a neurovegetative ear acupressure effect in patients with chronic insomnia by using heart rate variability analysis. Heart rate (HR) and heart rate variability (HRV) measurements in 31 patients (mean age?±?SD: 54.3?±?10.6 years) were performed under s...

Wang, Lu; Cheng, Weiping; Sun, Zhongren; Xu, Yangyang; Cheng, Guangyu; Gaischek, Ingrid; Kuang, Haixue; Litscher, Gerhard

28

Volitional Control of the Heart Rate.  

UK PubMed Central (United Kingdom)

The heart rate is largely under control of the autonomic nervous system. The aim of the present study is to investigate interactions between the brain and heart underlying volitional control of the heart and to explore the effectiveness of volition as a strategy to control heart rate without biofeedback. Twenty seven healthy male subjects voluntarily participated in the study and were instructed to decrease and increase their heart beats according to rhythmic, computer generated sound either 10% faster or slower than the subjects' measured heart rate. Sympathetic and parasympathetic activities were estimated with heart rate variability (HRV) obtained by power spectral analysis of RR intervals. Functional coupling patterns of cerebral cortex with heart were determined by Partial Directed Coherence (PDC). In HRslow task; HR and sympathetic activity significantly decreased. However parasympathetic activity and power spectral density of EEG in low Alpha (8 -10.5Hz) band significantly increased. Moreover information flow from parietal area (P3 and P4) to RR interval significantly increased. During HRquick task; HR, sympathetic activity and power spectral density of EEG in low Beta (14 -24Hz) band significantly increased. Parasympathetic activity significantly decreased. Information flow from FT8, CZ and T8 electrodes to RR interval significantly increased. Our findings suggested that the heart beat can be controlled by volition and is related to some special areas in the cortex.

Abukonna A; Yu X; Zhang C; Zhang J

2013-06-01

29

Heart rate reduction in heart failure: ivabradine or beta blockers?  

Science.gov (United States)

Ivabradine, a selective I f current inhibitor, decreasing the heart rate in those with sinus rhythm, has been added to the most recent European guidelines on heart failure. It is indicated in addition to beta blockers in patients with decreased left ventricular ejection fraction and sinus rate of over 70 beats per minute. Several well-designed studies including the BEAUTIFUL and the SHIFT trials demonstrated clear benefits of ivabradine in symptomatic patients, both with angina and with heart failure, with left ventricular systolic dysfunction. The main objective of this review is to provide a comprehensive summary of data on ivabradine, and to discuss the potential role of this new agent in the spectrum of modern therapeutics for heart failure. PMID:22972475

Guglin, Maya

2013-07-01

30

Heart rate reduction in heart failure: ivabradine or beta blockers?  

UK PubMed Central (United Kingdom)

Ivabradine, a selective I f current inhibitor, decreasing the heart rate in those with sinus rhythm, has been added to the most recent European guidelines on heart failure. It is indicated in addition to beta blockers in patients with decreased left ventricular ejection fraction and sinus rate of over 70 beats per minute. Several well-designed studies including the BEAUTIFUL and the SHIFT trials demonstrated clear benefits of ivabradine in symptomatic patients, both with angina and with heart failure, with left ventricular systolic dysfunction. The main objective of this review is to provide a comprehensive summary of data on ivabradine, and to discuss the potential role of this new agent in the spectrum of modern therapeutics for heart failure.

Guglin M

2013-07-01

31

Metaiodobenzylguanidine and heart rate variability in heart failure  

International Nuclear Information System (INIS)

[en] It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac 123I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF. (author)

1998-01-01

32

Metaiodobenzylguanidine and heart rate variability in heart failure  

Energy Technology Data Exchange (ETDEWEB)

It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac {sup 123}I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF. (author)

Kurata, Chinori; Shouda, Sakae; Mikami, Tadashi; Uehara, Akihiko; Ishikawa, Keiko [Hamamatsu Univ., Shizuoka (Japan). School of Medicine; Tawarahara, Kei; Nakano, Tomoyasu; Matoh, Fumitaka; Takeuchi, Kazuhiko

1998-10-01

33

Heart Rate Variability in Obstructive Sleep Apnea.  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Obstructive Sleep Apnea (OSA) is characterized by repeated episodes of upper airway obstruction leading to increased airway resistance and respiratory effort, producing oxygen desaturation, hypercapnia and central nervous system arousal. The intermittent hypoxemia and carbon-dioxide retention is responsible for the changes in autonomic and hemodynamic responses to sleep. Heart rate variability (HRV) is a marker of autonomic activity and can be analyzed using time-domain and frequency-domain methods. This study was undertaken to compare the HRV in patients with Obstructed Sleep Apnoea Syndrome (OSAS) and normal subjects. Methods: Heart rate variability in 30 controls (Group I) and 30 patients with Obstructive Sleep Apnea Syndrome (Group II) aged 35-45 yrs was studied by using electrocardiographic data obtained during Polysomnography. Low frequency (LF) power, High frequency (HF) power and Low frequency/ High frequency ratio (LF/HF) were analyzed using frequency-domain analysis. Results: There was a significant difference (p Conclusion: In our study, there was evidence of increased Sympathetic activity and a Parasympathetic attenuation in patients with Obstructive Sleep Apnea. Further studies can evaluate the usefulness of HRV indices for the non-invasive screening of asymptomatic patients suspected to have OSAS.

Selvakumar Jagannathan; Suzanne Maria D'cruz; Valarmathy Selvakumar; Vishwanatha Rao Badanidiyur

2013-01-01

34

Heart rate differentiates urgency and emergency in hypertensive crisis.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To study the clinical significance of presenting blood pressure parameters and heart rate in patients with hypertensive crisis. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Al Bannay R; Böhm M; Husain A

2013-08-01

35

Selective heart rate reduction with ivabradine unloads the left ventricle in heart failure patients.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The study aimed to determine whether isolated heart rate reduction with ivabradine reduces afterload of patients with systolic heart failure. BACKGROUND: The effective arterial elastance (Ea) represents resistive and pulsatile afterload of the heart derived from the pressure volume relation. Heart rate modulates Ea, and, therefore, afterload burden. METHODS: Among the patients with systolic heart failure (EF?35%) randomized to either placebo or ivabradine in the SHIFT (Systolic Heart failure treatment with the I(f) inhibitor ivabradine Trial) study, 275 (n=132 with placebo, n=143 with ivabradine 7.5mg bid) were included in the echocardiographic substudy. Ea, total arterial compliance (TAC) and end-systolic elastance (Ees) were calculated at baseline and after 8 months of treatment. Blood pressure was measured by arm cuff; stroke volume, ejection fraction and end-diastolic volume were assessed by echocardiography. RESULTS: At baseline Ea, TAC, heart rate and Ees did not differ significantly between ivabradine and placebo- treated patients. After 8 months of treatment heart rate was significantly reduced in the ivabradine group (p<0.0001) and was accompanied by marked reduction in Ea (p<0.0001) and improved TAC (p=0.004) compared to placebo. While contractility remained unchanged, ventricular-arterial coupling was markedly improved (p=0.002) resulting in a higher stroke volume (p<0.0001) in the ivabradine-treated patients. CONCLUSION: Isolated heart rate reduction by ivabradine improves total arterial compliance, thus reducing Ea. Since Ees is unaltered, improved ventricular-arterial coupling is responsible for increased stroke volume. Therefore, unloading of the heart may contribute to the beneficial effect of isolated heart rate reduction in patients with systolic heart failure.

Reil JC; Tardif JC; Ford I; Lloyd SM; O Meara E; Komajda M; Borer JS; Tavazzi L; Swedberg K; Bohm M

2013-07-01

36

APPARATUS FOR MEASUREMENT OF HEART RATE VARIABILITY  

UK PubMed Central (United Kingdom)

The present invention provides an apparatus for measurement of heart rate variability, comprising a main body of a earphone to be inserted into a patient's ear, a light source disposed on one side of the main body, emitting light projected onto the skin of the patient's ear, and a sensor disposed on the same side of the main body with the light source, receiving a reflection light from the skin of the patient's ear, and accordingly generating and transmitting a sensing signal to an analyzer for measurement of the heart rate variability. Thus, the heart rate variability of the patient can be measured by operation of the light source and the sensor when the patient is listening to the music through the earphone. In this way, true heart rate variability, without being affected by the patient's nervousness or impatience, can be derived.

HU WEI-CHIH; CHANG CHAO-FENG

37

Erythrocyte sedimentation rate as a marker for coronary heart disease  

Directory of Open Access Journals (Sweden)

Full Text Available Josef YayanDepartment of Internal Medicine, Vinzentius Hospital, Landau, GermanyBackground: Patients with angina pectoris or myocardial infarction frequently present without evidence of cardiac-specific heart enzymes by laboratory analysis or specific pathologic electrocardiogram findings. The current study analyzed the efficacy of the erythrocyte sedimentation rate as an additional potential indicator for coronary heart disease, the aim being to enable quicker identification of patients with angina pectoris or myocardial infarction so that they can be more rapidly treated.Methods: Patients with angina pectoris or myocardial infarction who had undergone a heart catheter examination were included in the study. The diagnosis of acute coronary heart disease was made by the physician who performed coronary angiography. Patients without coronary heart disease were used as a control group. The erythrocyte sedimentation rate was measured in all patients. Patients with angina pectoris or myocardial infarction and an inflammatory or tumor disease were excluded.Results: The erythrocyte sedimentation rate was prolonged in 79 (58.09%) of 136 patients; 69 (50.74%) patients (95% confidence interval ±8.4%, 42.34%–59.14%) had coronary heart disease and a prolonged erythrocyte sedimentation rate. The erythrocyte sedimentation rate was prolonged in ten (7.35%) patients (95% confidence interval ±4.39%, 2.96%–11.74%) without coronary heart disease by coronary angiography. The specificity of the erythrocyte sedimentation rate for coronary heart disease was 70.59% and the sensitivity was 67.65%.Conclusion: Erythrocyte sedimentation rate may be a useful additional diagnostic criterion for coronary heart disease.Keywords: erythrocyte sedimentation rate, coronary heart disease, myocardial infarction, coronary angiography

Yayan J

2012-01-01

38

Atrial fibrillation and heart failure: beyond the heart rate.  

UK PubMed Central (United Kingdom)

PURPOSE OF REVIEW: Atrial fibrillation and heart failure are two of the most prevalent cardiovascular disease conditions. They often coexist and lead to significant morbidity and mortality. Adequate management strategies for this dual epidemic continue to be the subject of many research studies. RECENT FINDINGS: Recent clinical trials suggest that a rhythm control strategy for atrial fibrillation does not offer a survival advantage over rate control in heart failure patients with reduced systolic function. Rhythm control in these trials was achieved using antiarrhythmic drugs, with evidence of increased mortality associated with certain agents. Catheter ablation is a more effective and increasingly used approach to maintain sinus rhythm in atrial fibrillation patients, with promising results in the heart failure population. Late-gadolinium-enhancement cardiac MRI (LGE-MRI) assessment of atrial fibrosis helps in selecting the better candidates for atrial fibrillation ablation. AV nodal ablation and bi-ventricular pacing remains another viable option. Atrial fibrillation patients with heart failure and preserved systolic function are another group in whom maintenance of sinus rhythm is thought to be advantageous. SUMMARY: Patients with atrial fibrillation and heart failure are a heterogeneous group and require a personalized treatment approach. Catheter ablation to restore and maintain sinus rhythm is a modality that promises to be advantageous beyond rate control.

Garg A; Akoum N

2013-05-01

39

The relationship between phase and heart rate  

International Nuclear Information System (INIS)

[en] The Fourier phase image is used in rest and stress radionuclide angiocardiography to assess the timing of ventricular wall motion in a regional fashion, and areas of high phase are taken to reprensent areas of delayed contraction. However, phase increases with heart rate and this can make interpretation difficult. This study investigates the relationship between phase and heart rate. A heterogenous group of 43 subjects was studied by ECG-gated equilibrium radionuclide angiocardiography, all of the subjects having normal extent of left ventricular wall motion as judged by normal ejection fraction and normal amplitude image. Mean left ventricular phase correlated well with mean time of end systole (r=0.92), but there was no correlation with time of end diastole.Thus phase reflects the time of end systole as a proportion of cycle length and should be linearly related to heart rate provided the duration of systole is unchanged. In 28 normal subjects mean left ventricular phase correlated linearly with resting rate (r=0.91), and when exercised the relationship was maintained up to 90 beats per minute. Above this rate the increases were less marked as the duration of systole shortened. The same was true in 4 subjects paced at different rates. Mean resting heart rate in the normal subjects was 70 beats per minute and correcting phase linearly to rate 70 did not change mean left ventricular phase but did decrease the standard deviation from 18 degree to 12 degree. It is concluded that correcting phase for heart rate below 90 beats per minute will increase the sensitivity of the phase image to abnormalities of the timing of ventricular contraction. This correction should be appropriate in resting, isometric exercise, and cold pressor studies but because of the higher heart rates involved will not be appropriate for bicycle exercise. (Author)

1984-01-01

40

Increased heart rate variability during nondirective meditation.  

UK PubMed Central (United Kingdom)

PURPOSE: Meditation practices are in use for relaxation and stress reduction. Some studies indicate beneficial cardiovascular health effects of meditation. The effects on the autonomous nervous system seem to vary among techniques. The purpose of the present study was to identify autonomic nerve activity changes during nondirective meditation. MATERIALS AND METHODS: Heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) were monitored in 27 middle-aged healthy participants of both genders, first during 20?min regular rest with eyes closed, thereafter practising Acem meditation for 20?min. Haemodynamic and autonomic data were collected continuously (beat-to-beat) and non-invasively. HRV and BPV parameters were estimated by power spectral analyses, computed by an autoregressive model. Spontaneous activity of baroreceptors were determined by the sequence method. Primary outcomes were changes in HRV, BPV, and BRS between rest and meditation. RESULTS: HRV increased in the low-frequency (LF) and high-frequency (HF) bands during meditation, compared with rest (p?=?0.014, 0.013, respectively). Power spectral density of the RR-intervals increased as well (p?=?0.012). LF/HF ratio decreased non-significantly, and a reduction of LF-BPV power was observed during meditation (p?heart rates remained unchanged. Blood pressure increased slightly during meditation. CONCLUSION: There is an increased parasympathetic and reduced sympathetic nerve activity and increased overall HRV, while practising the technique. Hence, nondirective meditation by the middle aged may contribute towards a reduction of cardiovascular risk.

Nesvold A; Fagerland MW; Davanger S; Ellingsen Ø; Solberg EE; Holen A; Sevre K; Atar D

2012-08-01

 
 
 
 
41

What is the “normal” fetal heart rate?  

Directory of Open Access Journals (Sweden)

Full Text Available Aim. There is no consensus about the normal fetal heart rate. Current international guidelines recommend for the normal fetal heart rate (FHR) baseline different ranges of 110 to 150 beats per minute (bpm) or 110 to 160 bpm. We started with a precise definition of “normality” and performed a retrospective computerized analysis of electronically recorded FHR tracings. Methods. We analyzed all recorded cardiotocography tracings of singleton pregnancies in three German medical centers from 2000 to 2007 and identified 78,852 tracings of sufficient quality. For each tracing, the baseline FHR was extracted by eliminating accelerations/decelerations and averaging based on the “delayed moving windows” algorithm. After analyzing 40% of the dataset as “training set” from one hospital generating a hypothetical normal baseline range, evaluation of external validity on the other 60% of the data was performed using data from later years in the same hospital and externally using data from the two other hospitals. Results. Based on the training data set, the “best” FHR range was 115 or 120 to 160 bpm. Validation in all three data sets identified 120 to 160 bpm as the correct symmetric “normal range”. FHR decreases slightly during gestation. Conclusions. Normal ranges for FHR are 120 to 160 bpm. Many international guidelines define ranges of 110 to 160 bpm which seem to be safe in daily practice. However, further studies should confirm that such asymmetric alarm limits are safe, with a particular focus on the lower bound, and should give insights about how to show and further improve the usefulness of the widely used practice of CTG monitoring.

Stephanie Pildner von Steinburg; Anne-Laure Boulesteix; Christian Lederer; Stefani Grunow; Sven Schiermeier; Wolfgang Hatzmann; Karl-Theodor M. Schneider; Martin Daumer

2013-01-01

42

What is the "normal" fetal heart rate?  

UK PubMed Central (United Kingdom)

Aim. There is no consensus about the normal fetal heart rate. Current international guidelines recommend for the normal fetal heart rate (FHR) baseline different ranges of 110 to 150 beats per minute (bpm) or 110 to 160 bpm. We started with a precise definition of "normality" and performed a retrospective computerized analysis of electronically recorded FHR tracings. Methods. We analyzed all recorded cardiotocography tracings of singleton pregnancies in three German medical centers from 2000 to 2007 and identified 78,852 tracings of sufficient quality. For each tracing, the baseline FHR was extracted by eliminating accelerations/decelerations and averaging based on the "delayed moving windows" algorithm. After analyzing 40% of the dataset as "training set" from one hospital generating a hypothetical normal baseline range, evaluation of external validity on the other 60% of the data was performed using data from later years in the same hospital and externally using data from the two other hospitals. Results. Based on the training data set, the "best" FHR range was 115 or 120 to 160 bpm. Validation in all three data sets identified 120 to 160 bpm as the correct symmetric "normal range". FHR decreases slightly during gestation. Conclusions. Normal ranges for FHR are 120 to 160 bpm. Many international guidelines define ranges of 110 to 160 bpm which seem to be safe in daily practice. However, further studies should confirm that such asymmetric alarm limits are safe, with a particular focus on the lower bound, and should give insights about how to show and further improve the usefulness of the widely used practice of CTG monitoring.

Pildner von Steinburg S; Boulesteix AL; Lederer C; Grunow S; Schiermeier S; Hatzmann W; Schneider KT; Daumer M

2013-01-01

43

Heart rate during training and competition for long-distance running.  

UK PubMed Central (United Kingdom)

Heart rate monitors are used widely by scientists, coaches and sports participants to monitor heart rate during physical activity. Although there are data that show that heart rate monitors measure heart rate accurately during a range of physical activities, there is less consensus on the interpretation of heart rate data. The day-to-day variation in heart rate under controlled submaximal exercise conditions is approximately 6 beats min (-1), which is generally less than the decrease in the submaximal heart rate that results from endurance training. A bout of exercise that causes moderate dehydration can affect heart rate during submaximal exercise. It has been estimated that, for every 1% loss in body weight due to dehydration, heart rate increases by 7 beats min (-1). During a 10-km race, the heart rate is approximately 20 beats min (-1) higher at racing pace compared to the heart rate at the same running speed under non-competitive conditions. In conclusion, heart rate monitors measure heart rate accurately under diverse conditions, and have the potential to be regarded as 'ergogenic aids'. However, further scientific studies are needed before the heart rate data can be interpreted accurately and used to improve long-distance running performance.

Lambert MI; Mbambo ZH; St Clair Gibson A

1998-01-01

44

Heart Rate Variability Analysis in General Medicine  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Yi Gang; Marek Malik

2003-01-01

45

Interdependence of parameters of varia-tional pulsometry, entropy of heart rate, temporal and spectral analyses of heart rate variability in normal state and in ischemic heart disease  

Directory of Open Access Journals (Sweden)

Full Text Available The research goal is to study the correlation between indices of variational pulsometry, entropy of heart rate, temporal and spectral analyses and heart rate variability in healthy patients and patients with coronary heart disease. Materials. Of the study are indicators of variational pulsometry and temporal and spectral analyses from 111 patients with coronary heart disease and in 61 healthy individuals. Results. Most parameters of HRV correlated with each other. In healthy patients the greatest independence was characterized by Mo and LF/HF, in patients with coronary artery disease — only by LF/HF Significant correlation with SDNN RMSSD, TP, LF, HF was determined. Conclusion. The variational pulsometry, temporal and spectral analyses of HRV and entropy of heart rate provide HRV assessment. The indices are interdependent and indicate interchangeability of methods

Durnova N.Yu.; Dovgalevskiy Ya.P.; Burlaka A.N.; Kiselev A. R.; Furman N.V.

2011-01-01

46

Wireless monitoring of Heart Rate using Microcontroller  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes the development of wireless monitoring of a heart rate based on a microcontroller. We can record the ECG signals and Heart beats of all patients in a single computer. These biomedical signals are acquired and then processed with a microcontroller. After processing, all data are sent to a communication interface that can send this information to a personal computer. For the patient suffering from the cardiac disease it is very necessary to perform accurate and quick diagnosis. For this purpose a continuous monitoring of the ECG signal, patient’s current heart rate and BP are essential. We can monitor the patient’s ECG signal by using Bluetooth transmission and reception in the central place in any hospital. The MATLAB software is used to simulate the ECG waveform.

J.S. Prasath

2013-01-01

47

Prediction of sleep bruxism events by increased heart rate.  

UK PubMed Central (United Kingdom)

PURPOSE: To investigate the hypothesis that sleep bruxism (SB) events could be predicted by an increase in heart rate. MATERIALS AND METHODS: Fourteen sleep bruxers were recruited. Each participant recorded his or her own electromyography (EMG) and electrocardiography (ECG) at home for 2 consecutive nights using a portable telemetry system. Ten heartbeats before (B10 to B1) and three heartbeats after (A1 to A3) the onset of SB events were analyzed, and the threshold for the prediction of an SB event was determined. The validity of the threshold was tested by EMG and ECG recorded in the same manner for an additional night. The prediction accuracy of SB events was evaluated for sensitivity and specificity. RESULTS: A gradual increase in heart rate was observed before an SB event, and B1, A1, A2, and A3 were significantly higher than B10 (P < .01). The threshold value was set at 110% when the mean of all heart rates of the second night of recording was set at 100%. A total of 324 SB events were observed and 299 were preceded by increased heart rate that exceeded the threshold (sensitivity, 92.3%). The total number of increased heart rate events was 1,239, and the total number of threshold applications was estimated to be 120,000. The specificity was 99.2%. CONCLUSION: Over 90% of SB events could be predicted by an increasing heart rate of 110%. Since the sensitivity and specificity were extremely high, the hypothesis that SB events could be predicted by increased heart rate was positively verified.

Mizumori T; Sumiya M; Kobayashi Y; Inano S; Yatani H

2013-05-01

48

Heart rate variability and heart rate recovery in patients with type 1 diabetes mellitus.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Patients with diabetes mellitus (DM) are at an increased risk of sudden cardiac death (SCD) partly explained by cardiac autonomic neuropathy (CAN). There have been fewer studies to evaluate CAN using heart rate variability (HRV) and heart rate recovery (HRR) in patients with type 2 DM.To our knowledge, there has been no study to investigate the association between HRR, HRV and type 1 DM. The purpose of this study was to examine the changes in HRR and HRV measurements in type 1 diabetic patients. METHODS: The study population consisted of 35 consecutive patients with type 1 diabetes and 35 sex- and age-matched non-diabetic controls. We performed electrocardiography, echocardiography, Holter analysis, exercise stress test, routine biochemical tests including haemoglobin Ale, high-sensitivity C-reactive protein and evaluated the clinical characteristics. HRR was calculated by subtracting the heart rate values at the first minute of the recovery phase from the peak heart rate. Abnormal HRR was defined as HRR < or = 18 beats.The HRV analysis was performed in both time domain and frequency domain. RESULTS: In HRV analysis, type 1 diabetic patients had significantly lower time domain [SDNN (P=0.041), SDANN (P=0.016), r-MSSD (P<0.001), pNN50 (P<0.001)] and frequency domain [total power (P=0.002), VLF (P<0.001), LF (P<0.001), HF (P=0.001), LF/HF (P=0.034)] HRV parameters as compared to controls. In logistic regression analysis, the HRR (OR 0.927, 95% CI 0.872 to 0.985, P= 0.014), METs (OR 0.562, 95% CI 0.355 to 0.890, P= 0.014), pNN50 (OR 0.729, 95% CI 0.566 to 0.941, P= 0.015) and HF (OR 0.952, 95% CI 0.911 to 0.994, P= 0.027) were independently associated with type 1 DM. CONCLUSION: The results of this study showed that HRV parameters and HRR were significantly reduced in patients with type 1 versus healthy controls. We found that HRV parameters correlated with HRR in type 1 diabetic patients. There is a relationship between CAN and inflammation and also, there may be a relationship between CAN and intensive glycaemic control according to this study.

Turker Y; Aslantas Y; Aydin Y; Demirin H; Kutlucan A; Tibilli H; Turker Y; Ozhan H

2013-04-01

49

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

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate the basic characteristics of passive smoking population, and the impact of passive smoking on heart rate variability, heart rate and blood pressure. METHODS: 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. RESULTS: (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 (SDNNindex) 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 the control group (all P < 0.01). (3) Heart rate and diastolic blood pressure were significantly higher in passive smoking group than in control group (all P < 0.05) while systolic blood pressure was similar between the 2 groups (P > 0.05). CONCLUSIONS: Marriage status, education level, profession and daily working time are independent determinants for passive smoking. Passive smoking mainly occurred in the workplace, entertainment venues and restaurants. Passive smoking is linked with reduced heart rate variability, increased 24 h average heart rate and diastolic blood pressure.

Zhao J; He F; Hu DY; Ding RJ; Yu XJ; Wang L; Zhang P; Li XB; Guo JH; Liu WL; Li CL; Li L; Gao CY; Zhao LS; Chu YJ; Huang ZW; Wei JH; Hua SH; Liu RY; Zhuang XF

2013-05-01

50

Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients  

Directory of Open Access Journals (Sweden)

Full Text Available 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 maximum age-adjusted value should be considered an effort near the maximum. This information may be useful in rehabilitation programs and ischemic tests, although further studies are required.

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

2008-01-01

51

Resting heart rate and outcomes in patients with cardiovascular disease: where do we currently stand?  

UK PubMed Central (United Kingdom)

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.

Menown IB; Davies S; Gupta S; Kalra PR; Lang CC; Morley C; Padmanabhan S

2013-08-01

52

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

UK PubMed Central (United Kingdom)

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 bpm (p <0.01). Likewise, comparing the groups ?75 and <75 bpm, the primary endpoint was significantly increased in the group of patients with heart rates ?75 bpm 27 vs. 12.2 %; p < 0.01). 5-year event-free survival was significantly lower among patients with heart rates ?70 bpm as compared to those with <70 bpm (log-rank test p < 0.05) and among patients in the ?75 bpm group versus <75 bpm group (log-rank test p < 0.01). In conclusion, in clinical practice, 53 % of CHF patients have inadequate heart rate control (heart rates ?75 bpm) despite concomitant beta-blocker therapy. In this non-randomized cohort, adequate heart rate control under individually optimized beta-blocker therapy was associated with improved mid- and long-term clinical outcome up to 5 years. As further up titration of beta-blockers is not achievable in many patients, the administration of a selective heart rate lowering agent, such as ivabradine adjuvant to beta-blockers may pose an opportunity to further modulate outcome.

Franke J; Wolter JS; Meme L; Keppler J; Tschierschke R; Katus HA; Zugck C

2013-01-01

53

Possible influence on heart rate on tinnitus.  

Science.gov (United States)

Assuming the possibility of the inner ear damage due to a hemodynamic imbalance essentially due to an abnormal vasomotor regulatory response, the possibility that heart rate (HR) has a correlation with the onset and/or the enhancement of tinnitus is hypothesized. In fact, recent studies have drawn the influence of other factors than blood pressure, in normotensive subjects, in taking part to the regulation of peripheral resistance, outlining the importance of both cardiac output (CO) - which is a function of heart rate (HR) and stroke volume (SV) and SV itself as a dynamic component to baroreflex control of muscle sympathetic nerve activity (MSNA). From this point of view, it could be possible that a condition of bradycardia can enhance tinnitus regardless of its cause, and conversely that a more elevated HR can be related to a relief of this symptom. PMID:18951725

Pirodda, Antonio; Brandolini, Cristina; Ferri, Gian Gaetano; Raimondi, Maria Chiara; Modugno, Giovanni Carlo; Esposti, Daniela Degli; Borghi, C

2008-10-31

54

Possible influence on heart rate on tinnitus.  

UK PubMed Central (United Kingdom)

Assuming the possibility of the inner ear damage due to a hemodynamic imbalance essentially due to an abnormal vasomotor regulatory response, the possibility that heart rate (HR) has a correlation with the onset and/or the enhancement of tinnitus is hypothesized. In fact, recent studies have drawn the influence of other factors than blood pressure, in normotensive subjects, in taking part to the regulation of peripheral resistance, outlining the importance of both cardiac output (CO) - which is a function of heart rate (HR) and stroke volume (SV) and SV itself as a dynamic component to baroreflex control of muscle sympathetic nerve activity (MSNA). From this point of view, it could be possible that a condition of bradycardia can enhance tinnitus regardless of its cause, and conversely that a more elevated HR can be related to a relief of this symptom.

Pirodda A; Brandolini C; Ferri GG; Raimondi MC; Modugno GC; Esposti DD; Borghi C

2009-01-01

55

Effects of aerobic training on heart rate  

Directory of Open Access Journals (Sweden)

Full Text Available Regular physical exercise is an important factor to reduce the indexes of cardiovascular and all causes morbimortality. However, there is, apparently, additional and independent benefits of the regular practice of physical exercise and the improvement of the level of aerobic condition. Heart rate (HR) is mediated primarily by the direct activity of the autonomic nervous system (ANS), specifically through the sympathetic and parasympathetic branches activities over the sinus node autorhythmicity, with predominance of the vagal activity (parasympathetic) at rest, that is progressively inhibited since the onset of the exercise. The HR behavior has been widely studied during different conditions and protocols associated to the exercise. A reduction of the cardiac vagal tone (parasympathetic function) and consequently a diminished HR variability in rest, independently of the protocol of measurement used, is related to an autonomic dysfunction, chronic-degenerative diseases and increased mortality risk. Individuals with high levels of aerobic condition have a lower resting HR, along with a larger parasympathetic activity or smaller sympathetic activity, but it is not necessarily a direct consequence of the exercise training, as long as other inherent adaptations to the aerobic conditioning can influence the resting HR. The HR response in the onset of the exercise represents the integrity of the vagus nerve, and the HR recovery on the post-exercise transient also denotes important prognostic information; by the way, individuals that have a slow HR recovery in the first minute post-exercise have increased mortality risk. In conclusion, the physiological mechanisms modulating HR during or after an exercise program are not totally clear, and further studies are needed.

Almeida Marcos B.; Araújo Claudio Gil S.

2003-01-01

56

Heart rate and heart rate variability in dogs with different degrees of myxomatous mitral valve disease  

DEFF Research Database (Denmark)

HEART RATE AND HEART RATE VARIABILITY IN DOGS WITH DIFFERENT DEGREES OF MYXOMATOUS MITRAL VALVE DISEASE. CE Rasmussen1, T Falk1, NE Zois1, SG Moesgaard1, HD Pedersen2, J Häggström3 and LH Olsen1. 1. Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark. 2. Novo Nordic A/S, Maaloev, Denmark. 3. Department of Clinical Sciences, Swedish University of Agricultural Science, Uppsala, Sweden. Heart rate variability (HRV) is an indirect measurement of the autonomic modulation of heart rate (HR). Reduced HRV measured from short-time electrocardiography is seen in dogs with heart failure (HF) secondary to myxomatous mitral valve disease (MMVD). However, HRV is suggested to increase with disease severity at early stages of MMVD. The aims of this study were 1) to associate HR and HRV with severity of MMVD in Cavalier King Charles Spaniels (CKCS) and 2) to compare HR and HRV between CKCS and other dog breeds in a group of dogs in HF secondary toMMVD. One-hundred dogs were examined by echocardiography and 24-hour electrocardiography. The dogs were divided into five groups: 1) CKCS with no/minimal mitral regurgitation (MR) (MR jet=15% of the left atrial area using color Doppler mapping) and no murmur, 2) CKCS with mild MR (20%50%) and no clinical signs of HF, 4) CKCS in HF (HF defined as left atrium to aortic root ratio (LA/Ao) >1.5, clinical signs of HF and furosemide responsiveness) and 5) non-CKCS in HF. Dogs in HF were allowed HF therapy. Both HR and HRV were analysed over a 24-hour period, while HRV were also analysed over a 6-hour nightly period. Analyses of variance were performed with HR or HRV as response variables and the explanatory variables dog group and echocardiographic indices of MMVD were included separately. All P-values were Bonferroni corrected. Minimum- and mean HR were significantly higher in CKCS with moderate/severe MR and in HF compared to CKCS with no/minimal and mild MR (all P<0.001). Seven out of 26 HRV variables were significantly decreased in CKCS with moderate/severe MR and in HF compared to CKCS with no/minimal and mild MR (all P<0.02). Another 10 HRV variables showed the same groupwise differences (all P<0.02), except that the difference between CKCS with mild MR and CKCS with moderate/severe MR did not reach statistical significance. Minimum HR, mean HR and the HRV variables (7 and 10) differing between dog groups, also consistently decreased with increasing MR, LA/Ao and the proximal isovelocity surface area in CKCS. Non-CKCS in HF had a lower minimum HR compared to CKCS in HF (P=0.03) and a higher triangular index measured in both periods (all P<0.04). In conclusion, HR increased and most HRV variables decreased with increasing severity of MMVD in CKCS, even prior to the development of HF. Other breeds in HF secondary to MMVD had lower minimum HR, but higher triangular index compared to CKCS in HF.

Rasmussen, Caroline Elisabeth; Falk, Bo Torkel

2011-01-01

57

Effect of endotoxemia on heart rate dynamics in rat isolated perfused hearts  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Beat-to-beat variation in heart rate shows a complex dynamics, and this complexity is changed during systemic inflammatory response syndrome (e.g. sepsis). It is not known whether or not cardiac pacemaker dynamical rhythm is affected by sepsis. The aim of this study was to investigate heart rate dynamics of isolated heart as well as expression of pacemaker channels (HCN) in a rat model of sepsis (endotoxemia) compared with normal rats. Methods: Male rats weighing 250-300 g were used in this study. Bacterial lipopolysaccharide was injected intraperitoneally (1mg/kg) in the endotoxemia group, and sterile saline in the control group. Three hours after injection, cardiac tissues were isolated and studied using Langendorff apparatus. Heart rate dynamics was assessed by calculating the standard deviation of inter-beat intervals as well as detrended fluctuation analysis (DFA). Quantitative RT-PCR was used to assess HCN expression in atria. Results: Hypoxia had a significantly different effect on heart rate variability in endotoxemic rats compared with controls (P<0.05). DFA analysis showed a linear relationship between logarithm of variance and the logarithm of scale in both endotoxemic and control rats. Atrial expression of HCN1 and HCN2 at mRNA level were significantly higher in endotoxemic rats in comparison with controls (P<0.05). Conclusion: Spontaneous beatings of isolated hearts exhibit a fractal-like dynamics which did not change after global hypoxia and/or endotoxemia. Endotoxemia was associated with altered heart rate variability and increased expression of pacemaker channels that might play a role in pathophysiology of cardiac complications of sepsis.

Mohammad Karim Azadbakht; Roham Mazloom; Shahram Shahabi; AliReza Mani

2013-01-01

58

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

UK PubMed Central (United Kingdom)

BACKGROUND: 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. METHODS AND RESULTS: 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). CONCLUSIONS: 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.

Giardini A; Fenton M; Derrick G; Burch M

2013-09-01

59

Voluntary heart rate reduction following yoga using different strategies.  

UK PubMed Central (United Kingdom)

BACKGROUND/AIMS: One month of yoga training has been shown to reduce the pulse rate voluntarily without using external cues. Hence, the present study was designed to understand the strategies used by yoga practitioners and autonomic changes associated with voluntary heart rate reduction. MATERIALS AND METHODS: Fifty volunteers (group mean age ± S.D., 25.4 ± 4.8 years; 25 males) were assessed in two trials on separate days. Each trial was for 12 minutes, with a 'pre' state and 'during' state of 6 minutes each. For both trials the 'pre' state was relaxation with eyes closed. In the 'during' state of Trial I, subjects were asked to voluntarily reduce their heart rate using a strategy of their choice. From their responses to specific questions it was determined that 22 out of 50 persons used breath regulation as a strategy. Hence, in the 'during' state of Trial II, subjects were asked to voluntarily reduce their heart rate by breath regulation. RESULTS: In the first trial, the heart rate was reduced by an average of 19.6 beats per minute and in the second trial (with breath regulation exclusively) an average decrease of 22.2 beats per minute was achieved. CONCLUSIONS: Hence, the strategy used did not markedly alter the outcome.

Raghavendra B; Telles S; Manjunath N; Deepak K; Naveen K; Subramanya P

2013-01-01

60

Heart rate and heart rate variability as indirect markers of surgeons' intraoperative stress.  

UK PubMed Central (United Kingdom)

OBJECTIVE: In a difficult and demanding environment such as the operating room, the individual workload response of physicians is of particular importance. The aim of this study was to examine the specific effects of intraoperative stress on the cardiovascular system by measuring heart rate (HR) and heart rate variability (HRV). METHODS: In a cross-sectional study, the effect of intraoperative stress on autonomic balance, measured by HRV, among surgeons differing with respect to their intraoperative stress levels was studied. Based on their perceived stress (State Trait Anxiety Inventory), surgeons were classified into a stressed and a non-stressed sample. Data on HR and HRV were collected by means of ambulatory ECG-recordings. Changes in autonomic nervous system activity were quantified by frequency and time domain analysis of R-R interval variability. Demographic, anthropometric, and surgery-related group differences were assessed by non-parametric Mann-Whitney U test, differences between relative changes of HR and HRV by Wilcoxon signed-ranks test. In multivariate linear analysis of covariance, group differences were adjusted for possible confounding factors. RESULTS: There was a significant difference in intraoperative HR for stressed and non-stressed surgeons (median: 99.3 vs. 63.7; P < 0.05). During sleep, HRV indices indicated a reduced autonomic recovery in stressed participants. CONCLUSIONS: Our results reveal that higher perceived stress in the operating room is associated with increased intraoperative HR and decreased HRV at night. Non-stressed surgeons show greater relaxation during sleep compared to their stressed colleagues.

Rieger A; Stoll R; Kreuzfeld S; Behrens K; Weippert M

2013-02-01

 
 
 
 
61

Heart rate in coronary artery disease: should we lower it?  

UK PubMed Central (United Kingdom)

OPINION STATEMENT: Elevated resting heart rate is an independent risk factor for cardiovascular morbidity and mortality in patients with and without coronary artery disease. In patients with known coronary artery disease, elevated heart rate reduces diastolic filling time and increases cardiac workload, resulting in supply demand mismatch with consequent ischemia and angina. While lower heart rate is associated with better prognosis, it is not known if pharmacological reduction in heart rate is beneficial and if heart rate is merely a marker for increased risk and worse outcomes. Certainly, physiologically lower resting heart rate as attained by exercise improves morbidity and mortality. While physiological reduction in heart rate is mainly a manifestation of increased parasympathetic drive, pharmacological reduction of heart rate with beta-blockers is mediated via the sympathetic pathway and associated with mixed outcomes. In addition, beta-blockers have other cardiovascular effects (lowering blood pressure), are metabolically active, and it is unknown if the beneficial effects (if any) are mediated via reduction in heart rate versus other cardiovascular effects. Ivabradine is a new medication that lowers heart rate selectively by inhibiting the I(f) current without other cardiovascular effects, offering for the first time a therapeutic agent that selectively targets heart rate. The medication has shown promise in early trials in patients with heart failure, but it is unclear if this agent will be beneficial in patients with stable coronary artery disease without heart failure.

Axsom K; Bangalore S

2013-02-01

62

Influence of semen collection on salivary cortisol release, heart rate, and heart rate variability in stallions.  

UK PubMed Central (United Kingdom)

The aim of this study was to evaluate the stress response of stallions (n = 16) aged 3-13 years with previous sexual experience to semen collection by determination of heart rate, heart rate variability, and cortisol in saliva. Recordings were done on two consecutive days. The time intervals from leaving the box until arrival in the collection barn and from first exposure to the teaser mare until ejaculation as well as the number of mounts until ejaculation were neither affected by collection day nor by age, sexual experience (i.e., the number of breeding seasons the stallion experienced), or sexual workload of the stallion (i.e., the mean number of semen collections per week). Heart rate was continuously determined from 30 minutes before to 30 minutes after ejaculation and significantly increased in response to the semen collection procedure (P < 0.001). Changes in heart rate were significantly influenced by sexual experience (P < 0.01) and sexual workload (P < 0.05) but not by the age of the stallions. Day of semen collection did not have any effects. The heart rate variability variable root mean square of successive RR differences was not affected by semen collection procedures. Cortisol concentration in saliva was determined from 60 minutes before to 120 minutes after ejaculation and did not change significantly. The results indicate that semen collection is perceived as not more than a modest temporary stressor in sexually experienced and well-trained stallions.

Pasing S; von Lewinski M; Wulf M; Erber R; Aurich C

2013-08-01

63

Influence of semen collection on salivary cortisol release, heart rate, and heart rate variability in stallions.  

Science.gov (United States)

The aim of this study was to evaluate the stress response of stallions (n = 16) aged 3-13 years with previous sexual experience to semen collection by determination of heart rate, heart rate variability, and cortisol in saliva. Recordings were done on two consecutive days. The time intervals from leaving the box until arrival in the collection barn and from first exposure to the teaser mare until ejaculation as well as the number of mounts until ejaculation were neither affected by collection day nor by age, sexual experience (i.e., the number of breeding seasons the stallion experienced), or sexual workload of the stallion (i.e., the mean number of semen collections per week). Heart rate was continuously determined from 30 minutes before to 30 minutes after ejaculation and significantly increased in response to the semen collection procedure (P < 0.001). Changes in heart rate were significantly influenced by sexual experience (P < 0.01) and sexual workload (P < 0.05) but not by the age of the stallions. Day of semen collection did not have any effects. The heart rate variability variable root mean square of successive RR differences was not affected by semen collection procedures. Cortisol concentration in saliva was determined from 60 minutes before to 120 minutes after ejaculation and did not change significantly. The results indicate that semen collection is perceived as not more than a modest temporary stressor in sexually experienced and well-trained stallions. PMID:23664794

Pasing, Stephanie; von Lewinski, Mareike; Wulf, Manuela; Erber, Regina; Aurich, Christine

2013-05-09

64

Technical note: a noninvasive procedure for measuring goat heart rates.  

UK PubMed Central (United Kingdom)

Heart rates were obtained simultaneously from FM radio transmitters and heart rate monitors externally mounted on unanesthetized and unrestrained mixed-breed goats. Data from transmitters were highly correlated (r = .92, P < .0001) with data from monitors and the percentage difference in heart rates between the two devices was less than that observed between animals. Analyses also revealed that radio transmitters provided a reliable, repeatable, and valid method for the noninvasive measurement of goat heart rates.

Besch EL; Varosi SM; Brigmon RL

1992-11-01

65

Analysis of heart rate variability in polycystic ovary syndrome.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To compare the modulation of heart rate in a group of volunteers with polycystic ovary syndrome (PCOS) to that of a group of healthy ovulatory women on the basis of R-R interval variability and analyze the relationships between heart rate variability (HRV) and other cardiovascular risk factors. METHODS: In a cross-sectional study, HRV and anthropometric, biochemical and hormonal parameters were measured in 23 women with PCOS and 23 age-matched controls. Mean outcomes measures: HRV indexes in the time (SDNN and rMSSD) and frequency domain (low frequency-LF and high frequency-HF). Differences between groups and correlation analysis were performed. RESULTS: Intergroup analysis showed significant differences (p < 0.05) between groups, with lower SDNN, rMSSD, LF and HF indexes in PCOS women when compared to the control group. There was significant negative correlation between BMI and SDNN, LF and HF, indicating a decrease in the autonomic modulation of heart rate with increasing weight. A negative correlation was also found between the high-sensitivity C-reactive protein level and the rMSSD index. CONCLUSION: Our results show that PCOS is associated with alterations in the autonomic modulation of heart rate, possibly due to the influence of weight gain.

de Sá JC; Costa EC; da Silva E; Zuttin RS; da Silva EP; Lemos TM; De Azevedo GD

2011-06-01

66

Adaptation of autonomic heart rate regulation in astronauts after spaceflight.  

UK PubMed Central (United Kingdom)

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.

Vandeput S; Widjaja D; Aubert AE; Van Huffel S

2013-01-01

67

Adaptation of autonomic heart rate regulation in astronauts after spaceflight.  

Science.gov (United States)

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

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

2013-01-04

68

Determination of heart rate variability with an electronic stethoscope.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Heart rate variability (HRV) is widely used to characterize cardiac autonomic function by measuring beat-to-beat alterations in heart rate. Decreased HRV has been found predictive of worse cardiovascular (CV) outcomes. HRV is determined from time intervals between QRS complexes recorded by electrocardiography (ECG) for several minutes to 24 h. Although cardiac auscultation with a stethoscope is performed routinely on patients, the human ear cannot detect heart sound time intervals. The electronic stethoscope digitally processes heart sounds, from which cardiac time intervals can be obtained. METHODS: Accordingly, the objective of this study was to determine the feasibility of obtaining HRV from electronically recorded heart sounds. We prospectively studied 50 subjects with and without CV risk factors/disease and simultaneously recorded single lead ECG and heart sounds for 2 min. RESULTS: Time and frequency measures of HRV were calculated from R-R and S1-S1 intervals and were compared using intra-class correlation coefficients (ICC). CONCLUSION: The majority of the indices were strongly correlated (ICC 0.73-1.0), while the remaining indices were moderately correlated (ICC 0.56-0.63). In conclusion, we found HRV measures determined from S1-S1 are in agreement with those determined by single lead ECG, and we demonstrate and discuss differences in the measures in detail. In addition to characterizing cardiac murmurs and time intervals, the electronic stethoscope holds promise as a convenient low-cost tool to determine HRV in the hospital and outpatient settings as a practical extension of the physical examination.

Kamran H; Naggar I; Oniyuke F; Palomeque M; Chokshi P; Salciccioli L; Stewart M; Lazar JM

2013-02-01

69

Heart rate variability, sleep and sleep disorders.  

UK PubMed Central (United Kingdom)

Heart rate (HR) is modulated by the combined effects of the sympathetic and parasympathetic nervous systems. Therefore, measurement of changes in HR over time (heart rate variability or HRV) provides information about autonomic functioning. HRV has been used to identify high risk people, understand the autonomic components of different disorders and to evaluate the effect of different interventions, etc. Since the signal required to measure HRV is already being collected on the electrocardiogram (ECG) channel of the polysomnogram (PSG), collecting data for research on HRV and sleep is straightforward, but applications have been limited. As reviewed here, HRV has been applied to understand autonomic changes during different sleep stages. It has also been applied to understand the effect of sleep-disordered breathing, periodic limb movements and insomnia both during sleep and during the daytime. HRV has been successfully used to screen people for possible referral to a Sleep Lab. It has also been used to monitor the effects of continuous positive airway pressure (CPAP). A novel HRV measure, cardiopulmonary coupling (CPC) has been proposed for sleep quality. Evidence also suggests that HRV collected during a PSG can be used in risk stratification models, at least for older adults. Caveats for accurate interpretation of HRV are also presented.

Stein PK; Pu Y

2012-02-01

70

HEART RATE DURING SLEEP: IMPLICATIONS FOR MONITORING TRAINING STATUS  

Directory of Open Access Journals (Sweden)

Full Text Available Resting heart rate has sometimes been used as a marker of training status. It is reasonable to assume that the relationship between heart rate and training status should be more evident during sleep when extraneous factors that may influence heart rate are reduced. Therefore the aim of the study was to assess the repeatability of monitoring heart rate during sleep when training status remained unchanged, to determine if this measurement had sufficient precision to be used as a marker of training status. The heart rate of ten female subjects was monitored for 24 hours on three occasions over three weeks whilst training status remained unchanged. Average, minimum and maximum heart rate during sleep was calculated. The average heart rate of the group during sleep was similar on each of the three tests (65 ± 9, 63 ± 6 and 67 ± 7 beats·min-1 respectively). The range in minimum heart rate variation during sleep for all subjects over the three testing sessions was from 0 to 10 beats·min-1 (mean = 5 ± 3 beats·min-1) and for maximum heart rate variation was 2 to 31 beats·min-1 (mean = 13 ± 9 beats·min-1). In summary it was found that on an individual basis the minimum heart rate during sleep varied by about 8 beats·min-1. This amount of intrinsic day-to-day variation needs to be considered when changes in heart rate that may occur with changes in training status are interpreted

Miriam R. Waldeck; Michael I. Lambert

2003-01-01

71

Heart Rate and Cardiovascular Disease: An Alternative to Beta Blockers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ivabradine, an If inhibitor, acts primarily on the sinoatrial node and is used to reduce the heart rate with minimal effect on myocardial contractility, blood pressure, and intracardiac conduction. Heart rate reduction is an important aspect of care in patients with chronic stable angina and heart f...

Liang, Michael; Puri, Aniket; Devlin, Gerard

72

Significance of reduction in heart rate in cardiovascular disease.  

Science.gov (United States)

Epidemiologic studies suggest that lower heart rate is associated with decreased cardiovascular and all-cause mortality. Heart rate has also been reported to be an independent predictor of outcome after myocardial infarction (MI). Because it is a major determinant of oxygen consumption and metabolic demand, a decrease in heart rate would be expected to decrease cardiac workload. Among patients with restricted coronary blood flow, increased heart rate is associated with more severe myocardial ischemia, angina, and an increase in size of MI. Pharmacologic interventions that reduce heart rate, such as beta blockers, generally reduce mortality and improve outcome. A number of clinical trials using beta blockers after MI has shown a relationship between reduction in heart rate and reduction in mortality. Most beta blockers demonstrate a nearly linear relationship between reductions in mortality and in heart rate. The evidence from trials with calcium antagonists is more equivocal, possibly because until very recently none were available that decreased heart rate without decreasing myocardial contractility. Drugs that do not reduce the heart rate after an MI and in congestive heart failure have not been found to improve survival. In light of the findings thus far reported, reduction in heart rate should be a therapeutic goal in the treatment of cardiovascular disease. PMID:9853192

Hjalmarson, A

1998-12-01

73

Significance of reduction in heart rate in cardiovascular disease.  

UK PubMed Central (United Kingdom)

Epidemiologic studies suggest that lower heart rate is associated with decreased cardiovascular and all-cause mortality. Heart rate has also been reported to be an independent predictor of outcome after myocardial infarction (MI). Because it is a major determinant of oxygen consumption and metabolic demand, a decrease in heart rate would be expected to decrease cardiac workload. Among patients with restricted coronary blood flow, increased heart rate is associated with more severe myocardial ischemia, angina, and an increase in size of MI. Pharmacologic interventions that reduce heart rate, such as beta blockers, generally reduce mortality and improve outcome. A number of clinical trials using beta blockers after MI has shown a relationship between reduction in heart rate and reduction in mortality. Most beta blockers demonstrate a nearly linear relationship between reductions in mortality and in heart rate. The evidence from trials with calcium antagonists is more equivocal, possibly because until very recently none were available that decreased heart rate without decreasing myocardial contractility. Drugs that do not reduce the heart rate after an MI and in congestive heart failure have not been found to improve survival. In light of the findings thus far reported, reduction in heart rate should be a therapeutic goal in the treatment of cardiovascular disease.

Hjalmarson A

1998-12-01

74

Gender differences of heart rate variability in healthy volunteers.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To identify the basic values of heart rate variability in Pakistani population and to verify our hypothesis that there are gender differences in cardiovascular autonomic modulation. METHODS: The descriptive cross sectional study based on convenience probability sampling was conducted at Armed Forces Institute of Cardiology/National Institute of Heart Diseases (AFIC/NIHD) Pakistan. The duration of the study was from December 2009 to July 2010. It involved 24-hour holter monitoring of 45 healthy individuals using holter electrocardiography (ECG) recorder. Heart rate variability was analysed in time (SDNN, SDANN, SDNNi, rMSSD, pNN50) and frequency domains (power, VLF, LF, and HF). RESULTS: The time domain indices; SDNN (male = 140 +/- 36ms vs. females = 122 +/- 33ms; p = 0.09), SDANN (male = 123 +/- 34ms vs. females = 111 +/- 34ms; P = 0.23), SDNNi (male = 64 +/- 19ms vs. females = 52 +/- 14ms; P = 0.03), and pNN50 (male = 14 +/- l0ms vs. females = 12 +/- 7ms; P = 0.43) were decreased in female volunteers when compared with males. Comparison of frequency domain indices; Total power (male = 4041 +/- 3150ms(2) vs. females = 2750 +/- 1439ms(2); P = 0.07), VLF (male = 2912 +/- 2675ms(2) vs. females = 1843 +/- 928ms(2); P = 0.06), LF (male = 788 +/- 397ms(2) vs. females = 556 +/- 346ms(2); P = 0.04) and HF (male = 318 +/- 251ms(2) vs. females = 312 +/- 277ms(2): P = 0.94) amongst males and females showed attenuated heart rate variability in females. Of all the observed values, SDNNi and LF were found significantly (p < 0.05) decreased in women. CONCLUSION: In healthy population, heart rate variability is low in women than men. It reflects sympathetic dominance in women in our population.

Saleem S; Hussain MM; Majeed SM; Khan MA

2012-05-01

75

Global Heart Failure Rates and Erythropoietin  

Directory of Open Access Journals (Sweden)

Full Text Available Global variation in heart failure (HF) prevalence and mortality rates is evident and multiple factors have been hypothesised to explain such non-random distribution. The author hypothesised that this non-random HF distribution could be attributed, in part, to individual variation in the level of erythropoietin (EPO), a hormone and a possible cardioprotectant. Such individual EPO variation can be explained by hypoxia resulting from regional differences in geographic elevation. This hypothesis was justified using results from various animal-based and clinical studies. In addition, data from the population-based Healthcare Cost and Utilization Project was used. The global distribution of HF can be explained, in part, by the geographic landscape. Prospective studies based on the author’s hypothesis may provide new treatment opportunities for such an important health issue as HF. In addition, this hypothesis may demonstrate new insights into the mechanism of HF.

Rovshan M. Ismailov

2012-01-01

76

Erythropoietin, Heart Disease and Global Rate  

Directory of Open Access Journals (Sweden)

Full Text Available In medicine, the relationship between erythropoietin and heart disease is sometimes mentioned. An attempt to demonstrate connection between erythropoietin and heart failure is very interesting. The attempt is based on the interrelationship among erythropoietin disturbance, anemia and heart disorder. However, the factors that can affect the endemic pattern must be considered

Viroj Wiwanitkit

2013-01-01

77

Heart rate variability and red cell distribution width in patients with systolic left heart failure.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Red cell distribution width (RDW) is a strong prognostic marker for systolic left heart failure regardless of the anemia status, and heart rate variability (HRV) is negatively associated with mortality and sudden cardiac death in patients with systolic left heart failure. Their relationship has not been investigated in the previous literature. DESIGN: One hundred eighty four patients who had been previously diagnosed with systolic left heart failure (with ischemic or non-ischemic etiology) were retrospectively enrolled in our study. Patients underwent 24-h electrocardiographic monitoring, and blood samples for RDW and other variables were analyzed. Study population was grouped into tertiles of RDW (Tertile 1: 13.4 ± 1.4%, Tertile 2: 14.6 ± 1.4%, and Tertile 3: 17.1 ± 1.2%). RESULTS: Most of the characteristics of patients were similar among RDW tertiles. Standard deviation of all normal RR intervals (SDNN), standard deviation of the averages of RR intervals in all 5-min segments (SDANN) and root-mean square of difference of successive RR intervals (RMSSD) values significantly differed among groups (p < 0.001). The highest RDW tertile had the lowest HRV values, and Pearson correlation analysis yielded a negative correlation between HRV parameters and RDW (for SDNN, SDANN, RMSSD; r = 0.373, 0.340, 0.362, respectively, p < 0.001 for all). In stepwise multivariate analysis HRV was independently associated with RDW. CONCLUSIONS: The HRV parameters were independently associated with RDW in patients with systolic left heart failure.

Özcan F; Turak O; Avci S; Tok D; ??leyen A; Aras D; Aydo?du S

2013-08-01

78

Ordinal pattern statistics for the assessment of heart rate variability  

Science.gov (United States)

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.

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

2013-06-01

79

Harmonic relationship between preferred tempi and heart rate.  

UK PubMed Central (United Kingdom)

Since people tend to prefer musical tempi ranging from 70 to 100 beats per minute, cyclic physiological response like heart rate is considered on of the factors affected by tempo preference. The present study aimed to examine the relationship between preferred tempi and heart rate. Subjects were instructed to find their favorite tempi while their hart rates were being measured. The presented tone stimulus was 440 Hz, 60 dB pressure of pure tone, and the presented tempo varied from 10 to 300 cycles per minute. The relationship between heart rate and preferred tempo was examined to calculate the density function of ratios of preferred tempi to heart rate. This density function indicated that preferred tempi were distributed mostly one, one and a half, and two times as fast as heart rate. This finding indicated preferred tempi had a simple harmonic relationship to heart rate.

Iwanaga M

1995-08-01

80

Conclusions and recommendations for electrical energy conservation based on the Washington Rate Demonstrations Project. [Motivation  

Energy Technology Data Exchange (ETDEWEB)

Based upon indications from previous research, a set of studies were conducted by a University of Washington research team to further explore the potential of using feedback to bring about conservation of electrical energy. Specifically, individual studies focused on feedback in the form of the utility bill itself when that bill reflects an increased rate; a more informative bill; daily meter readings; instantaneous information on electricity used in showers; continuous feedback on energy use by a household or a business as a whole; rebates; hints on achieving conservation; and meter-reading instructions. In gereral, the interventions found most effective entailed the use of feedback at relatively frequent intervals and in combination with an incentive or some other positive involvement of the subject. Thus (moderate) rate increases were found most effective for a short period after their implementation, and a month of daily meter readings resulted in significantly lower electricity use for about a year after the readings had been stopped. A shower-flow restrictor that involved the subject by enabling him to make adjustments in flow also seemed to hold promise for achieving significant conservation. Neither rebates nor non-contingent conservation information were found effective in producing energy conservation.

Kohlenberg, R.J.; Anschell, S.

1980-06-30

 
 
 
 
81

Heart rate variability in menopausal hot flashes during sleep.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The aim of this study was to determine if heart rate variability changes during hot flashes recorded during sleep. METHODS: This study was performed in a university medical center laboratory with 16 postmenopausal women demonstrating at least four hot flashes per night. Polysomnography, heart rate, and sternal skin conductance to indicate hot flashes were recorded in controlled, laboratory conditions. RESULTS: For the frequency bin of 0 to 0.15 Hz, spectral power was greater during waking compared with non-rapid eye movement sleep and less during stages 3 and 4 compared with stages 1 and 2. Power was greater during hot flashes compared with subsequent periods for all hot flashes. Power was greater during hot flashes compared with preceding and subsequent periods for those recorded during stage 1 sleep. For waking hot flashes, power in this band was higher before hot flashes than during or after them. CONCLUSIONS: These data are consistent with our theory of elevated sympathetic activation as a trigger for menopausal hot flashes and with previous work on heart rate variability during the stages of sleep.

Freedman RR; Kruger ML; Wasson SL

2011-08-01

82

Heart Rate Variability in Patients with Rheumatoid Arthritis  

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Full Text Available Background: Altered cardiovascular autonomic nerve function with impaired sympathovagal balance is found in rheumatoid arthritis (RA). Heart Rate Variability (HRV) analysis is an important tool for assessment of autonomic nerve activity.Objective: To assess cardiac autonomic nerve function status in patients with Rheumatoid arthritis (RA) by time domain measures of HRV.Methods: This cross sectional study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka from January to December 2010. Sixty female RA patients, age range 18-50 years were constituted study group enrolled from the Out- patient Rheumatology Wing, Department of Medicine, BSMMU. Age matched thirty apparently healthy females were studied as control. Time domain measures of Heart Rate Variability (HRV) such as Mean RR intervals, Mean HR, SDNN, RMSSD, NN50% and PNN 50% were recorded for 5 minutes by a Polygraph machine to observe cardiac autonomic nerve function activity. Data were analyzed by independent sample t test.Results: Mean R-R interval, SDNN, RMSSD, PNN50%, NN50% were significantly lower (p<0.001) but heart rate was significantly (P<0.001) higher in rheumatoid arthritis patients.Conclusion: Cardiac autonomic nerve function is impaired and characterized by reduced resting parasympathetic activity in female Rheumatoid Arthritis patients.

Kawser Jahan, Noorzahan Begum, Sultana Ferdousi

2012-01-01

83

Dissociation of heart rate variability and heart rate recovery in well-trained athletes.  

UK PubMed Central (United Kingdom)

The purpose of this investigation was to examine the relationships between aerobic fitness, volume of physical activity (PA), heart rate variability (HRV), and heart rate recovery (HRR) in a group of well-trained endurance athletes. Nineteen endurance athletes participated in this study and had aerobic capacities that placed them above the 99th percentile based on normative values (VO(2max): 67.1 ± 2 ml kg(-1) min(-1)). HRV was obtained via an EKG collected during supine rest and reported as high-frequency (HF), low-frequency (LF), and total power (TP). Natural log (ln) transformation was applied when variables violated assumptions of normality. HRR recovery was reported as the reduction in heart rate from peak exercise to the heart rate 1 min after cessation of exercise and PA was estimated from a questionnaire. HRR was significantly correlated with PA and VO(2max) (r = 0.67, P = 0.003 and 0.51, P = 0.039, respectively), but not with any index of HRV. Age was significantly correlated with lnHF (r = -0.49, P = 0.033), lnLF/lnHF (r = 0.48, P = 0.037), and normalized units (NU) of LF (r = 0.47, P = 0.042) and HF (r = -0.47, P = 0.042). Stepwise regression revealed that the strongest predictor of HRR was PA (R (2) = 0.45) and that VO(2max) did not add significant predictive value to the model. The relationship between HRV and age is evident in well-trained endurance athletes, whereas the relationship between HRV and PA/aerobic fitness is not. The maintained relationship between HRR and PA/aerobic fitness suggests that HRR may be a better marker of fitness-related differences in autonomic control in this population.

Lee CM; Mendoza A

2012-07-01

84

Prediction of heart rate response to conclusion of spontaneous breathing trial by fluctuation dissipation theory  

Science.gov (United States)

The non-equilibrium fluctuation dissipation theorem is applied to predict how critically ill patients respond to treatment, based upon data currently collected by standard hospital monitoring devices. This framework is demonstrated on a common procedure in critical care: the spontaneous breathing trial. It is shown that the responses of groups of similar patients to the spontaneous breathing trial can be predicted by the non-equilibrium fluctuation dissipation approach. This mathematical framework, when fully formed and applied to other clinical interventions, may serve as part of the basis for personalized critical care.

Chen, Man; Niestemski, Liang Ren; Prevost, Robert; McRae, Michael; Cholleti, Sharath; Najarro, Gabriel; Buchman, Timothy G.; Deem, Michael W.

2013-01-01

85

Prediction of heart rate response to conclusion of the spontaneous breathing trial by fluctuation dissipation theory.  

UK PubMed Central (United Kingdom)

The non-equilibrium fluctuation dissipation theorem is applied to predict how critically ill patients respond to treatment, based upon data currently collected by standard hospital monitoring devices. This framework is demonstrated on a common procedure in critical care: the spontaneous breathing trial. It is shown that the responses of groups of similar patients to the spontaneous breathing trial can be predicted by the non-equilibrium fluctuation dissipation approach. This mathematical framework, when fully formed and applied to other clinical interventions, may serve as part of the basis for personalized critical care.

Chen M; Niestemski LR; Prevost R; McRae M; Cholleti S; Najarro G; Buchman TG; Deem MW

2013-02-01

86

Prediction of heart rate response to conclusion of the spontaneous breathing trial by fluctuation dissipation theory.  

Science.gov (United States)

The non-equilibrium fluctuation dissipation theorem is applied to predict how critically ill patients respond to treatment, based upon data currently collected by standard hospital monitoring devices. This framework is demonstrated on a common procedure in critical care: the spontaneous breathing trial. It is shown that the responses of groups of similar patients to the spontaneous breathing trial can be predicted by the non-equilibrium fluctuation dissipation approach. This mathematical framework, when fully formed and applied to other clinical interventions, may serve as part of the basis for personalized critical care. PMID:23361135

Chen, Man; Niestemski, Liang Ren; Prevost, Robert; McRae, Michael; Cholleti, Sharath; Najarro, Gabriel; Buchman, Timothy G; Deem, Michael W

2013-01-30

87

Ear acupressure, heart rate, and heart rate variability in patients with insomnia.  

UK PubMed Central (United Kingdom)

This high-tech "teleacupuncture study" describes a neurovegetative ear acupressure effect in patients with chronic insomnia by using heart rate variability analysis. Heart rate (HR) and heart rate variability (HRV) measurements in 31 patients (mean age?±?SD: 54.3?±?10.6 years) were performed under standardized conditions in Harbin, China, and the data analysis was performed in Graz, Austria. Similar to our previous clinical and basic teleacupuncture research works, the electrocardiograms (ECGs) were recorded by an HRV Medilog AR12 system during ear acupressure of the Shenmen point on the left ear. HR decreased significantly (P < 0.05) during and after acupressure stimulation. The effect was not visible after the first stimulation, rather it appeared in the phase following the second acupressure stimulation (10 min after the first stimulation). Total HRV showed significant stimulation-dependent increases (P < 0.05), immediately after each acupressure stimulation with a maximum after the third stimulation (20 min after the first stimulation), but there was no long-lasting effect. The present results can serve as a solid basis for the further investigations of auricular point stimulation for noninvasive complementary use in treating insomnia.

Wang L; Cheng W; Sun Z; Xu Y; Cheng G; Gaischek I; Kuang H; Litscher G

2013-01-01

88

Ear acupressure, heart rate, and heart rate variability in patients with insomnia.  

Science.gov (United States)

This high-tech "teleacupuncture study" describes a neurovegetative ear acupressure effect in patients with chronic insomnia by using heart rate variability analysis. Heart rate (HR) and heart rate variability (HRV) measurements in 31 patients (mean age?±?SD: 54.3?±?10.6 years) were performed under standardized conditions in Harbin, China, and the data analysis was performed in Graz, Austria. Similar to our previous clinical and basic teleacupuncture research works, the electrocardiograms (ECGs) were recorded by an HRV Medilog AR12 system during ear acupressure of the Shenmen point on the left ear. HR decreased significantly (P acupressure stimulation. The effect was not visible after the first stimulation, rather it appeared in the phase following the second acupressure stimulation (10 min after the first stimulation). Total HRV showed significant stimulation-dependent increases (P acupressure stimulation with a maximum after the third stimulation (20 min after the first stimulation), but there was no long-lasting effect. The present results can serve as a solid basis for the further investigations of auricular point stimulation for noninvasive complementary use in treating insomnia. PMID:23476702

Wang, Lu; Cheng, Weiping; Sun, Zhongren; Xu, Yangyang; Cheng, Guangyu; Gaischek, Ingrid; Kuang, Haixue; Litscher, Gerhard

2013-02-11

89

Match analysis and heart rate of futsal players during competition.  

Science.gov (United States)

Heart rates were monitored and time-motion analysis performed for 10 players (mean age 25.6 years, s = 2.5; body mass 73.8 kg, s = 5.7 kg; height 1.75 m, s = 0.06) during four competitive futsal matches. Mean heart rate during the match was 90% (s = 2) of maximum heart rate. Heart rate records were classified based on the percentage of time spent in three zones (>85%, 85-65%, and futsal is a multiple-sprints sport in which there are more high-intensity phases than in soccer and other intermittent sports. PMID:17899472

Barbero-Alvarez, J C; Soto, V M; Barbero-Alvarez, V; Granda-Vera, J

2008-01-01

90

Study Heart Rate by Tools from Complex Networks  

International Nuclear Information System (INIS)

Heart rate measured as beat-to-beat time intervals varies in time. It is believed that time intervals between subsequent normal heart contractions carry information about the regulatory system of the heart. How to quantify such signals is not clear and because of that heart rate variability is still apart from the clinic routine. In the following, we propose a method for representing a heart rate signal as a directed network. Then we study the signal properties by complex network tools. The signals to study were collected from patients recovering after the heart transplantation. The aim is to classify the progress of adapting of the new heart - graft. Moreover, it is expected that the method allows for visual classification. Our investigations are preliminary, however the obtained results are promising. (authors)

2011-01-01

91

Impact of left bundle branch block on heart rate and its relationship to treatment with ivabradine in chronic heart failure.  

UK PubMed Central (United Kingdom)

AIMS: Left bundle branch block (LBBB) increases morbidity and mortality in heart failure (HF). Heart rate reduction with ivabradine improves outcomes in patients with systolic HF. Therefore, we aimed to analyse the impact of LBBB on outcomes in patients with systolic HF as a function of heart rate, and the relationship between LBBB and the effect of treatment with ivabradine. METHODS AND RESULTS: Patients from the SHIFT (n = 6505) were divided into groups with (n = 912) or without (n = 5593) LBBB at baseline, and according to tertiles of heart rate (70-73, 74-80, and ?81 b.p.m.). The effect of LBBB, heart rate, and ivabradine on the primary endpoint (cardiovascular death or HF hospitalization) and other endpoints was analysed. LBBB was associated with increases in the primary endpoint by 65%, cardiovascular mortality by 49%, HF hospitalization by 86%, and all-cause mortality by 49% (all P < 0.001). No interaction appeared between the impact of heart rate on outcomes and presence of LBBB (P = 0.83 for the primary endpoint); thus LBBB increases risk for all heart rates. No interaction was apparent in the effect of ivabradine with LBBB or without LBBB. Ivabradine did not increase the prevalence of bradycardia in patients with LBBB. CONCLUSION: LBBB increases risk in HF patients with heart rates ?70 b.p.m. in sinus rhythm, unmodulated by heart rate. Ivabradine was safe in LBBB. Its effect was directionally similar to that in patients without LBBB, but did not reach statistical significance, possibly due to lack of power to test this effect because of the small number of LBBB patients.

Reil JC; Robertson M; Ford I; Borer J; Komajda M; Swedberg K; Tavazzi L; Böhm M

2013-09-01

92

Is there a relationship between obesity, heart rate variability and inflammatory parameters in heart failure?  

UK PubMed Central (United Kingdom)

BACKGROUND: To investigate the effect of body mass index (BMI) on heart rate variability (HRV) and inflammatory parameters in patients with heart failure. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Taçoy G; Açikgöz K; Kocaman SA; Ozdemir M; Cengel A

2010-02-01

93

Highly comparative fetal heart rate analysis.  

UK PubMed Central (United Kingdom)

A database of fetal heart rate (FHR) time series measured from 7 221 patients during labor is analyzed with the aim of learning the types of features of these recordings that are informative of low cord pH. Our 'highly comparative' analysis involves extracting over 9 000 time-series analysis features from each FHR time series, including measures of autocorrelation, entropy, distribution, and various model fits. This diverse collection of features was developed in previous work [1]. We describe five features that most accurately classify a balanced training set of 59 'low pH' and 59 'normal pH' FHR recordings. We then describe five of the features with the strongest linear correlation to cord pH across the full dataset of FHR time series. The features identified in this work may be used as part of a system for guiding intervention during labor in future. This work successfully demonstrates the utility of comparing across a large, interdisciplinary literature on time-series analysis to automatically contribute new scientific results for specific biomedical signal processing challenges.

Fulcher BD; Georgieva AE; Redman CW; Jones NS

2012-01-01

94

Kubios HRV - Heart rate variability analysis software.  

UK PubMed Central (United Kingdom)

Kubios HRV is an advanced and easy to use software for heart rate variability (HRV) analysis. The software supports several input data formats for electrocardiogram (ECG) data and beat-to-beat RR interval data. It includes an adaptive QRS detection algorithm and tools for artifact correction, trend removal and analysis sample selection. The software computes all the commonly used time-domain and frequency-domain HRV parameters and several nonlinear parameters. There are several adjustable analysis settings through which the analysis methods can be optimized for different data. The ECG derived respiratory frequency is also computed, which is important for reliable interpretation of the analysis results. The analysis results can be saved as an ASCII text file (easy to import into MS Excel or SPSS), Matlab MAT-file, or as a PDF report. The software is easy to use through its compact graphical user interface. The software is available free of charge for Windows and Linux operating systems at http://kubios.uef.fi.

Tarvainen MP; Niskanen JP; Lipponen JA; Ranta-Aho PA; Karjalainen PO

2013-08-01

95

Heart Rate Variability Analysis in Different Age and Pathological Conditions  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Heart Rate Variability (HRV) has been used as a measure of mortality primarily with patients who had undergone cardiac surgery. The analysis of Heart Rate Variability (HRV) demands specific capabilities which are not provided either by parametric or nonparametric conventional estimation methods. The Empirical Mode Decomposition (EMD) adaptively estimates the Intrinsic Mode Functions (IMFs) of nonlinear nonstationary signals. Approach: The intrinsic mode functions estimated from the HRV signal were based on local characteristics of the signal. The principle objective was to analyze the HRV latencies of healthy subjects in different age and pathological conditions. The method was applied to HRV signal of 17 healthy young control subjects, 17 healthy old control subjects and 20 congestive heart failure patients for half hour duration. Results: The results showed that a healthy person?s HRV rapidly rises to its maximum response much earlier than the HRV of pathological subjects. The rising slope of the time scale?s plot discriminates the healthy controls and pathological subjects with 100% sensitivity and specificity. Conclusion: This fact makes the method a promising approach to be applied in clinical practice as a screening test for specific risk-groups.

M. E.S. Chelladurai; N. Kumaravel

2011-01-01

96

Heart rate turbulence and variability in patients with ventricular arrhythmias  

Directory of Open Access Journals (Sweden)

Full Text Available Background: To evaluate the changes in autonomic neural control mechanisms before malignant ventricular arrhythmias, we measured heart rate variability (HRV) and heart rate turbulence (HRT) in patients with ventricular tachycardia or fibrillation (Group I; n=6), non sustained ventricular tachycardia (Group II; n=32), frequent premature ventricular beats (Group III; n=26) and with ICD implantation (Group IV; n=11). Methods: Time domain parameters of HRV and turbulence onset (TO) and slope (TS) were calculated on 24 hour Holter recordings. Normal values were: SDNN > 70 msec for HRV, TO 2.5 msec/RR-I for HRT. Results: Whereas SDNN was within normal range and similar in all study groups, HRT parameters were significantly different in patients who experienced VT/VF during Holter recording. Abnormal TO and/or TS were present in 100% of Group I patients and only in about 50% of Group II and IV. On the contrary, normal HRT parameters were present in 40-70% of Group II, III and IV patients and none of Group I. Conclusions: These data suggest that HRT analysis is more suitable than HRV to detect those transient alterations in autonomic control mechanisms that are likely to play a major trigger role in the genesis of malignant cardiac arrhythmias. (Heart International 2007; 3: 51-7)

Federico Lombardi; Fabrizio Tundo; Abdalrahim Abukwaik; Diego Tarricone

2007-01-01

97

Heart rate turbulence and variability in patients with ventricular arrhythmias  

Directory of Open Access Journals (Sweden)

Full Text Available Background: To evaluate the changes in autonomic neural control mechanisms before malignant ventricular arrhythmias, we measured heart rate variability (HRV) and heart rate turbulence (HRT) in patients with ventricular tachycardia or fibrillation (Group I; n=6), non sustained ventricular tachycardia (Group II; n=32), frequent premature ventricular beats (Group III; n=26) and with ICD implantation (Group IV; n=11). Methods: Time domain parameters of HRV and turbulence onset (TO) and slope (TS) were calculated on 24 hour Holter recordings. Normal values were: SDNN > 70 msec for HRV, TO 2.5 msec/RR-I for HRT. Results: Whereas SDNN was within normal range and similar in all study groups, HRT parameters were significantly different in patients who experienced VT/VF during Holter recording. Abnormal TO and/or TS were present in 100% of Group I patients and only in about 50% of Group II and IV. On the contrary, normal HRT parameters were present in 40-70% of Group II, III and IV patients and none of Group I. Conclusions: These data suggest that HRT analysis is more suitable than HRV to detect those transient alterations in autonomic control mechanisms that are likely to play a major trigger role in the genesis of malignant cardiac arrhythmias. (Heart International 2007; 3: 51-7)

Federico Lombardi; Fabrizio Tundo; Abdalrahim Abukwaik; Diego Tarricone

2009-01-01

98

The influence of respiratory pattern on heart rate variability analysis in heart failure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Introduction. Autonomic dysfunction is present early in the course of heart failure, and has a direct role on deterioration of cardiac function and prognosis. Heart rate variability (HRV) estimates sympathovagal control of heart frequency. The influence of respiratory pattern on HRV is clinically im...

Zamaklar-Trifunovi? Danijela; Seferovi? Petar M.; Petrovi? Milan; Živkovi? Mirjana; Vukomanovi? Goran; Mili? Nataša

99

Variations in circadian heart rate in psychiatric disorders: theoretical and practical implications  

Directory of Open Access Journals (Sweden)

Full Text Available HG Stampfer,1 SB Dimmitt2 1School of Psychiatry and Clinical Neurosciences, University of Western Australia, 2School of Medicine and Pharmacology, University of Western Australia, Crawley, WA, AustraliaBackground: Data are presented to demonstrate dimensions of variation in circadian heart rate in patients under treatment for a psychiatric disorder and to comment on their clinical relevance.Method: Serial recordings of 24-hour heart rates were obtained from individuals under treatment for a psychiatric disorder and from healthy volunteers.Results: The mean 24-hour heart rate can vary independently of the circadian rate pattern or “rate architecture.” Sleep and waking heart rate can vary independently. Variations in circadian heart rate are state-dependent: broadly different clinical states are associated with distinctly different patterns of circadian heart rate, particularly during sleep.Conclusion: Different regulatory mechanisms or pathways are involved in mediating different aspects of circadian heart rate. An analysis of circadian heart rate can contribute useful physiological adjunct information to psychiatric assessment and the monitoring of patient response to treatment.Keywords: anxiety, depression, neuroendocrine regulation

Stampfer HG; Dimmitt SB

2013-01-01

100

Loss of lag-response curvilinearity of indices of heart rate variability in congestive heart failure  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Heart rate variability (HRV) is known to be impaired in patients with congestive heart failure (CHF). Time-domain analysis of ECG signals traditionally relies heavily on linear indices of an essentially non-linear phenomenon. Poincaré plots are commonly used to study non-linear behavior of physiologic signals. Lagged Poincaré plots incorporate autocovariance information and analysis of Poincaré plots for various lags can provide interesting insights into the autonomic control of the heart. Methods Using Poincaré plot analysis, we assessed whether the relation of the lag between heart beats and HRV is altered in CHF. We studied the influence of lag on estimates of Poincaré plot indices for various lengths of beat sequence in a public domain data set (PhysioNet) of 29 subjects with CHF and 54 subjects with normal sinus rhythm. Results A curvilinear association was observed between lag and Poincaré plot indices (SD1, SD2, SDLD and SD1/SD2 ratio) in normal subjects even for a small sequence of 50 beats (p value for quadratic term 3 × 10-5, 0.002, 3.5 × 10-5 and 0.0003, respectively). This curvilinearity was lost in patients with CHF even after exploring sequences up to 50,000 beats (p values for quadratic term > 0.5). Conclusion Since lagged Poincaré plots incorporate autocovariance information, these analyses provide insights into the autonomic control of heart rate that is influenced by the non-linearity of the signal. The differences in lag-response in CHF patients and normal subjects exist even in the face of the treatment received by the CHF patients.

Thakre Tushar P; Smith Michael L

2006-01-01

 
 
 
 
101

The heart beat does not make us tick: the impacts of heart rate and arousal on time perception.  

UK PubMed Central (United Kingdom)

According to popular models of human time perception, variations in prospective timing are caused by two factors: the pulse rate of an internal pacemaker and the amount of attention directed to the passage of time. The results concerning the effect of attention on subjective timing have been conclusive, but the mechanisms that drive the pacemaker are still far from being understood. In two experiments, we examined the impact of two factors that in the existing literature on human time perception have been argued to affect such a pacemaker: arousal and heart rate. Experienced arousal and heart rate were varied independently by means of specific physical exercises: (a) A muscle exercise increased arousal and heart rate; (b) a breath-holding exercise increased arousal but decreased heart rate; and (c) in the control condition, arousal and heart rate were held constant. The results indicate that increased subjective arousal leads to higher time estimates, whereas heart rate itself has no relevant impact on time perception. The results are discussed with respect to the underlying mechanisms of prospective time perception.

Schwarz MA; Winkler I; Sedlmeier P

2013-01-01

102

Heart Rate and Cardiovascular Disease: An Alternative to Beta Blockers  

Science.gov (United States)

Ivabradine, an If inhibitor, acts primarily on the sinoatrial node and is used to reduce the heart rate with minimal effect on myocardial contractility, blood pressure, and intracardiac conduction. Heart rate reduction is an important aspect of care in patients with chronic stable angina and heart failure. Many patients with coronary artery disease have coexisting asthma or chronic obstructive airway disease, and most of them are unable to tolerate beta blockers. Ivabradine may thus be a useful medicine in therapeutic heart rate management especially in patients who are intolerant of beta-blockers.

Liang, Michael; Puri, Aniket; Devlin, Gerard

2009-01-01

103

Heart rate variability analysis using a seismocardiogram signal.  

UK PubMed Central (United Kingdom)

Seismocardiography is a simple and non invasive method of recording cardiac activity from the movements of the body caused by heart pumping. In this preliminary study we use a smartphone to record this acceleration and estimate the heart rate. We compare the heart rate variability parameters from the seismocardiogram and ECG reference signal. The results show a great similarity and are strongly influenced by the instability in the sampling frequency of the device. The differences between RR series are lower than 10 ms.

Ramos-Castro J; Moreno J; Miranda-Vidal H; García-González MA; Fernández-Chimeno M; Rodas G; Capdevila L

2012-01-01

104

Discharge heart rate and future events among Japanese patients with acute heart failure receiving beta-blocker therapy  

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Full Text Available Background: Randomized trials have demonstrated the efficacy of beta-blockers (BBs) in heart failure (HF) patients. We sought to assess the impact of BBs on long-term outcome; in particular, we assessed the association between outcome and BB dose and discharge heart rate. Methods and Results: Prescriptions for dispensed medication and outcomes were identified from a prospective, single-institution HF registry. Long-term prognosis was compared between users and non-users of BBs. BB users were further divided into 2 groups based on dose (full and non-full dose) and discharge heart rate (70 bpm was significantly associated with impaired long-term outcome (HR = 1.872, P = 0.04). Conclusions: Optimizing heart rate, rather than maximizing BB dose, appears to be an appropriate treatment strategy for the beta-sensitive Japanese population.

Kazuki Oshima; Shun Kohsaka; Kimi Koide; Yuji Nagatomo; Toshiyuki Nagai; Yutaka Endo; Tsutomu Yoshikawa; Keiichi Fukuda

2013-01-01

105

Variation in heart rate influences the assessment of transient ischemic dilation in myocardial perfusion scintigraphy  

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Full Text Available Abstract Background Transient arrhythmias can affect transient ischemic dilation (TID) ratios. This study was initiated to evaluate the frequency and effect of normal heart rate change on TID measures in routine clinical practice. Methods Consecutive patients undergoing stress/rest sestamibi gated myocardial perfusion scintigraphy were studied (N = 407). Heart rate at the time of stress and rest imaging were recorded. TID ratios were analyzed in relation to absolute change in heart rate (stress minus rest) for subjects with normal perfusion and systolic function (Group 1, N = 169) and those with abnormalities in perfusion and/or function (Group 2, N = 238). Results In Group 1, mean TID ratio was inversely correlated with the change in heart rate (r = -0.47, P Conclusion Normal variation in heart rate between the stress and rest components of myocardial perfusion scans is common and can influence TID ratios in patients with normal and abnormal cardiac scans.

Leslie William D; Levin Daniel P; Demeter Sandor J

2007-01-01

106

Cycling cadence affects heart rate variability.  

Science.gov (United States)

The purpose of this study was to examine the effect different cycling cadences have on heart rate variability (HRV) when exercising at constant power outputs. Sixteen males had ECG and respiratory measurements recorded at rest and during 8, 10 min periods of cycling at four different cadences (40, 60, 80 and 100 revs min(-1)) and two power outputs (0 W (unloaded) and 100 W (loaded)). The cycling periods were performed following a Latin square design. Spectral analyses of R-R intervals by fast Fourier transforms were used to quantify absolute frequency domain HRV indices (ms(2)) during the final 5 min of each bout, which were then log transformed using the natural logarithm (Ln). HRV indices of high frequency (HF) power were reduced when cadence was increased (during unloaded cycling (0 W) log transformed HF power decreased from a mean [SD] of 6.3 [1.4] Ln ms(2) at 40 revs min(-1) to 3.9 [1.3] Ln ms(2) at 100 revs min(-1)). During loaded cycling (at 100 W), the low to high frequency (LF:HF) ratio formed a 'J' shaped curve as cadence increased from 40 revs min(-1) (1.4 [0.4]) to 100 revs min(-1) (1.9 [0.7]), but dipped below the 40 revs min(-1) values during the 60 revs min(-1) 1.1 (0.3) and 80 revs min(-1) 1.2 (0.6) cadence conditions. Cardiac frequency (f(C)) and ventilatory variables were strongly correlated with frequency domain HRV indices (r = -0.80 to -0.95). It is concluded that HRV indices are influenced by both cycling cadence and power output; this is mediated by the f(C) and ventilatory changes that occur as cadence or exercise intensity is increased. Consequently, if HRV is assessed during exercise, both power output/exercise intensity and cadence should be standardized. PMID:21693796

Lunt, Heather C; Corbett, Jo; Barwood, Martin J; Tipton, Michael J

2011-06-21

107

Heart rate variability in myotonic dystrophy type 1 patients.  

UK PubMed Central (United Kingdom)

BACKGROUND: Cardiac involvement is common in myotonic dystrophy (MD) patients. Heart rate variability (HRV) is a simple and reliable technique that can be useful for studying the influence of the autonomic nervous system on the heart. OBJECTIVE: Study heart rate variability in patients with type 1 MD. METHODS: We studied HRV during 5-minute recordings in MD patients and in a healthy control group. We analyzed frequency domains (LF and HF) in normalized units (nu) and sympathovagal balance, in the sitting and supine position. RESULTS: Seventeen patients (10 men and 7 women) and seventeen matched healthy individuals (10 men and 7 women) were studied. Sympathetic and parasympathetic modulations of the heart increased in male MD patients from supine to sitting position in 19% of LFnu and the LF/HF ratio rose by 42.3%. In the sitting position, male MD patients exhibited significantly higher sympathovagal balances in 50.9% compared to healthy control individuals. HRV was influenced by both gender and disease. Gender influenced LFnu in the supine position while the LF/HF ratio and HFnu were affected in both positions. Post hoc analyses showed that gender significantly impacts MD patients and healthy individuals in different ways (p < 0.01). The low frequency domain in the sitting position (LFnu) was significantly influenced by the disease. CONCLUSION: The results of this study suggest that the sympathetic drive in middle-aged male MD patients who are not severely impaired and present moderate disease duration seems to be greater than in healthy matched individuals.

Fregonezi G; Araújo T; Dourado Junior ME; Ferezini J; Silva E; Resqueti V

2012-04-01

108

Heart rate as a therapeutic target in angina pectoris.  

UK PubMed Central (United Kingdom)

Heart rate is a major determinant of cardiac output and myocardial oxygen utilization and is increasingly being nominated as a modifiable risk factor for cardiovascular disease. Despite this evidence, screening strategies for preventing cardiovascular diseases do not include routine assessment of resting heart rate. Reasonably, heart rate reduction has been suggested as a useful approach against angina pectoris in subjects with acute or chronic coronary syndromes. Accordingly, reduction of heart rate in patients with stable angina could be an additional goal of therapy. Important data have shown retrospectively the beneficial effect of heart rate-lowering drugs, such as betaadrenoceptor antagonists, non-dihydropyridine calcium channel antagonists, as well as other agents, on several parameters in patients with coronary artery disease and stable angina. However, additional data are now being sought to assess the impact of this approach on clinical practice.

Androulakis E; Tousoulis D; Papageorgiou N; Kontogeorgou A; Briasoulis A; Charakida M; Siasos G; Oikonomou E; Siama K; Latsios G; Stefanadis C

2013-01-01

109

Association between atrial fibrillatory rate and heart rate variability in patients with atrial fibrillation and congestive heart failure.  

UK PubMed Central (United Kingdom)

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Corino VD; Cygankiewicz I; Mainardi LT; Stridh M; Vasquez R; Bayes de Luna A; Holmqvist F; Zareba W; Platonov PG

2013-01-01

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Heart rate turbulence predicts all-cause mortality and sudden death in congestive heart failure patients.  

UK PubMed Central (United Kingdom)

BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: HRT is a potent risk predictor for both heart failure and arrhythmic death in patients with class II and III CHF.

Cygankiewicz I; Zareba W; Vazquez R; Vallverdu M; Gonzalez-Juanatey JR; Valdes M; Almendral J; Cinca J; Caminal P; de Luna AB

2008-08-01

111

Resting heart rate is a predictor of mortality in COPD.  

UK PubMed Central (United Kingdom)

The clinical significance of high heart rate in chronic obstructive pulmonary disease (COPD) is unexplored. We investigated the association between resting heart rate, pulmonary function, and prognosis in subjects with COPD. 16 696 subjects aged ?40 years from the Copenhagen City Heart Study, a prospective study of the general population, were followed for 35.3 years, 10 986 deaths occurred. Analyses were performed using time-dependent Cox-models and net reclassification index (NRI). Resting heart rate increased with severity of COPD (p<0.001). Resting heart rate was associated with both cardiovascular and all-cause mortality across all stages of COPD (p<0.001). Within each stage of COPD, resting heart rate improved prediction of median life expectancy; the difference between <65 bpm and >85 bpm was 5.5 years without COPD, 9.8 years in mild (Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I), 6.7 years in moderate (GOLD stage II) and 5.9 years in severe/very severe COPD (GOLD stage III/IV), (p<0.001). Resting heart rate significantly improved risk prediction when added to GOLD stage (categorical NRI 4.9%, p = 0.01; category less NRI 23.0%, p<0.0001) or forced expiratory volume in 1 s % predicted (categorical NRI 7.8%, p = 0.002; category less NRI 24.1%, p<0.0001). Resting heart rate increases with severity of COPD. Resting heart rate is a readily available clinical variable that improves risk prediction in patients with COPD above and beyond that of pulmonary function alone. Resting heart rate may be a potential target for intervention in COPD.

Jensen MT; Marott JL; Lange P; Vestbo J; Schnohr P; Nielsen OW; Jensen JS; Jensen GB

2013-08-01

112

Should we SHIFT our thinking about digoxin? Observations on ivabradine and heart rate reduction in heart failure.  

UK PubMed Central (United Kingdom)

AIMS: The importance of heart rate in the pathophysiology of heart failure with reduced LVEF has recently attracted attention. In particular, the findings of the Systolic Heart failure treatment with the I(f) inhibitor ivabradine Trial (SHIFT) have put special emphasis on heart rate reduction with ivabradine for improvement in clinical outcomes. Of course, there is a much older drug that reduces heart rate, i.e. digoxin. METHODS AND RESULTS: In this short commentary, we retrospectively analyse the Digitalis Investigation Group (DIG) Trial looking at the primary composite endpoint used in SHIFT (i.e. cardiovascular death or hospital admission for worsening heart failure) and compare the effect of digoxin on this endpoint with that of ivabradine. A remarkably similar risk reduction in the composite outcome and in its components appears evident among patients receiving the active treatment in both studies (although ivabradine was added to a beta-blocker, whereas digoxin was not). CONCLUSIONS: This raises the question of whether the Cardiological community dismissed digoxin too readily and if we should reappraise its potential role in the treatment of heart failure.

Castagno D; Petrie MC; Claggett B; McMurray J

2012-05-01

113

The effect of heart rate on the heart rate variability response to autonomic interventions  

Science.gov (United States)

Heart rate variability (HRV), the beat-to-beat variation in either heart rate (HR) or heart period (R-R interval), has become a popular clinical and investigational tool to quantify cardiac autonomic regulation. However, it is not widely appreciated that, due to the inverse curvilinear relationship between HR and R-R interval, HR per se can profoundly influence HRV. It is, therefore, critical to correct HRV for the prevailing HR particularly, as HR changes in response to autonomic neural activation or inhibition. The present study evaluated the effects of HR on the HRV response to autonomic interventions that either increased (submaximal exercise, n = 25 or baroreceptor reflex activation, n = 20) or reduced (pharmacological blockade: ?-adrenergic receptor, muscarinic receptor antagonists alone and in combination, n = 25, or bilateral cervical vagotomy, n = 9) autonomic neural activity in a canine model. Both total (RR interval standard deviation, RRSD) and the high frequency (HF) variability (HF, 0.24–1.04 Hz) were determined before and in response to an autonomic intervention. All interventions that reduced or abolished cardiac parasympathetic regulation provoked large reductions in HRV even after HR correction [division by mean RRsec or (mean RRsec)2 for RRSD and HF, respectively] while interventions that reduced HR yielded mixed results. ?-adrenergic receptor blockade reduced HRV (RRSD but not HF) while both RRSD and HF increased in response to increases in arterial blood (baroreceptor reflex activation) even after HR correction. These data suggest that the physiological basis for HRV is revealed after correction for prevailing HR and, further, that cardiac parasympathetic activity is responsible for a major portion of the HRV in the dog.

Billman, George E.

2013-01-01

114

Heart Rate and Heart Rate Variability Modification in Chronic Insomnia Patients.  

UK PubMed Central (United Kingdom)

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.

Farina B; Dittoni S; Colicchio S; Testani E; Losurdo A; Gnoni V; Di Blasi C; Brunetti R; Contardi A; Mazza S; Della Marca G

2013-10-01

115

Temperature to heart rate relationship in the neonate  

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Full Text Available In neonatal intensive care, measurement of heart rate is part of every clinical examination and it is used for monitoring hemodynamic status. However, it is influenced by some exogenous and endogenous factors, such as medication, pain, and stress. (1) Similarly, an increased heart rate is a normal physiological response to fever. Heart rate is known to increase by 10 beats per minute (bpm) per degree centigrade increase in body temperature in children. (2) In order to allow physicians to identify patients who have a higher heart rate than would be expected for a given level of temperature, Thompson et al. (3) created temperature specific heart rate centile charts adaptable to children from three months to ten years. Very few data exist on the relationship of temperature and heart rate in younger infants. The only study on this topic so far was performed in an emergency department that included infants up to the age of 12 months, where they found no linear correlation between fever and heart rate in the group of infants younger than two months. (4) To our knowledge no studies have ever addressed this issue in newborns.

Nora Hofer; Wilhelm Müller; Bernhard Resch

2012-01-01

116

Application of the Poincare plot to heart rate variability: a new measure of functional status in heart failure.  

UK PubMed Central (United Kingdom)

BACKGROUND: Conventional methods of quantifying heart rate variability using summary statistics have shown that decreased variability is associated with increased mortality in heart failure. However, many patients with heart failure have arrhythmias which make the 'raw' heart rate variability data less suitable for the use of summary statistical measures. AIMS: To examine the clinical potential of a new measure of heart rate variability data, presented by the Poincaré plot pattern, as an adjunct to the summary statistical measures of R-R interval variability. METHODS: We used the Poincaré plot pattern to display beat-to-beat heart rate variability data from a group of 23 patients with heart failure and compared them with data collected from 20 healthy age-matched control subjects. The data, which consists of 2000 consecutive R-R intervals, were gathered over 20-40 minutes while the subjects rested supine in a quiet darkened room. RESULTS: The morphological classification scheme proposed reflected the functional status of patients in heart failure. There was a significant difference (chi-square = 27.5, p < 0.0001) in the different pattern types between patients with NYHA Class I and II compared to patients with NYHA Class II and IV. All healthy subjects displayed a 'cluster' type of pattern characterised by normally distributed data. Sixteen of the 23 patients in heart failure also produced data which were normally distributed but the remaining seven produced data which required careful filtering to make them suitable for analysis using summary statistics, but which could be analysed by the Poincaré plot. CONCLUSIONS: The Poincaré plot pattern is a semi-quantitative tool which can be applied to the analysis of R-R interval data. It has potential advantages in that it allows assessment of data which are grossly non-Gaussian in distribution, and is a simple and easily implemented method which can be used in a clinical setting to augment the standard electrocardiogram to provide 'real time' visualisation of data.

Kamen PW; Tonkin AM

1995-02-01

117

Relation between heart rate, heart rhythm, and reverse left ventricular remodelling in response to carvedilol in patients with chronic heart failure: a single centre, observational study  

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Objective: To determine whether the process of reverse left ventricular remodelling in response to carvedilol is dependent on baseline heart rate (BHR), heart rhythm, or heart rate reduction (HRR) in response to carvedilol.

Arnold, R H; Kotlyar, E; Hayward, C; Keogh, A M; Macdonald, P S

118

Heart rate variability and extubation readiness in extremely preterm infants.  

UK PubMed Central (United Kingdom)

BACKGROUND: Mechanical ventilation (MV) is associated with changes in autonomic nervous system activity in preterm infants, which can be assessed by measurements of heart rate variability (HRV). Decreased HRV has been described in adults undergoing disconnection from MV; such information is not available in preterm infants. OBJECTIVE: To compare differences in HRV between infants successfully extubated and those who failed, and to evaluate the accuracy of HRV as a predictor of extubation readiness. METHODS: This is a prospective, observational study of infants with a birth weight ?1,250 g undergoing their first extubation attempt. Heart rate was measured during a 60-min period immediately prior to extubation and HRV was calculated using the frequency domain analysis. RESULTS: A total of 47 infants were studied; 36 were successfully extubated and 11 reintubated. There were no differences in patient demographics, ventilator settings, blood gases or postextubation management between the groups. All components of the HRV analysis were significantly decreased in infants who failed, generating high areas under the receiver operating characteristic curve. The specificity and positive predictive values were 100, but with limited sensitivity and negative predictive values. CONCLUSIONS: Infants considered 'ready to be extubated' but who subsequently failed their first extubation attempt had decreased HRV prior to extubation. Though promising, the value of HRV as a predictor of extubation readiness requires further evaluation.

Kaczmarek J; Chawla S; Marchica C; Dwaihy M; Grundy L; Sant'Anna GM

2013-01-01

119

Heart rate variability and turbulence analysis in patients with psoriasis  

Directory of Open Access Journals (Sweden)

Full Text Available Objectives: Psoriasis vulgaris (PV) is a chronic inflammatory skin disorder with increased incidence of many systemic abnormalities. However, the effects of psoriasis on autonomic nervous system have not been previously well-defined. Impaired autonomic function with an increase in sympathetic activity may be associated with ventricular arrhythmias and sudden cardiac death in the general population. Heart rate turbulence (HRT) is a noninvasive test to reflect the increased sympathetic tone and abnormal baroreflex sensitivity. The aim of current study was to investigate the effect of psoriasis on cardiac autonomic function by using HRT and heart rate variability (HRV) parameters as possible indicators of increased risk for ventricular arrhythmias and sudden cardiac death.Materials and methods: The study comprised 20 psoriatic patients without cardiovascular involvement and age and sex matched 20 healthy subjects. The severity of the disease was evaluated by the “Psoriasis Area and Severity Index”. The HRV and turbulence analysis were assessed from a 24-hour Holter recording.Results: There were no statistically significant differences between the two groups with respect to clinical, demographic and biochemical characteristics. When HRT parameters were compared; the values of the turbulence onset and slope in psoriatic patients were not significantly different from the control group (p>0.05). HRV parameters except for high frequency power (significantly lower in psoriatic patients, p0.05).Conclusion: Psoriasis appeared not to be associated with impaired autonomic function regarding to HRT and HRV values. Further investigations are needed to confirm these results

Asuman Biçer; Ramazan Akdemir; Özlem Karakurt; Havva Kaya Ak??; Betül Karasu; Yusuf Sezen; Ünal Güntekin; Ali Y?ld?z; Recep Demirba?; Fatma Eskio?lu

2010-01-01

120

Heart rate turbulence in patients with metabolic syndrome.  

UK PubMed Central (United Kingdom)

BACKGROUND: Metabolic syndrome is a cluster of risk factors leading to cardiometabolic diseases. The association between metabolic syndrome and cardiovascular disease (CVD) has been evaluated previously, but none of those studies looked at cardiac autonomic functions in these patients. The aim of the present study was to investigate the effect of metabolic syndrome on heart rate turbulence, which plays an important role in the development of CVD. METHODS: Thirty-seven patients (17 females and 20 males) were included in the metabolic syndrome group and 37 subjects (19 females and 18 males) were included in the control group. Heart rate turbulence (HRT) indices [turbulence onset (TO) and turbulence slope (TS)] were calculated from 24-hr ambulatory electocardiographic recordings. RESULTS: At least one of the TO or TS values were within the abnormal range in 62% of the patients within the metabolic syndrome group. In the control group, at least one of the TO or TS values were within the abnormal range in 27% of the subjects. CONCLUSIONS: Our study results indicate that cardiac autonomic function is impaired even in the absence of overt cardiac disease in patients with metabolic syndrome. Further studies are needed to elucidate the prognostic significance and clinical implications of impaired autonomic functions in patients with metabolic syndrome.

Y?lmaz M; Akyaz?c? F; Ar?can Ozluk O; Peker T; Karaagac K

2013-04-01

 
 
 
 
121

Vagal heart rate control in patients with atrial fibrillation: impact of tonic activation of peripheral chemosensory function in heart failure.  

UK PubMed Central (United Kingdom)

Heart failure (HF) and atrial fibrillation (AF), emerging as two epidemics of the twenty-first century, are commonly associated with each other. Both have been mechanistically linked to changes in cardiac vagal control. The importance of peripheral chemosensors, located in the carotid body, has not been elucidated so far. We therefore investigated whether tonic activation of excitatory chemoreceptor afferents contributes to the altered vagal control in HF patients with a history of AF. In 18 patients (72 ±9 year, 7 male) with sinus rhythm and a history of AF (n=9, without any evidence of structural heart disease, AF group; n=9 with structural heart disease and clinical presentation of HF, AFHF group) we investigated the impact of chemosensory deactivation (by breathing 100% oxygen) on heart rate, blood pressure, cardiac output, total peripheral resistance, oxygen saturation and breathing rate. Ten healthy individuals served as a control group. In addition, we performed a deep breathing test demonstrating an impaired heart rate variation in patients with and without HF as compared with controls (expiration/inspiration difference: 23.9±6.9 vs. 6.9±6.1 bpm, and 23.9±6.9 vs. 7.8±4.8 bpm; p<0.05). In both control and AF groups, heart rate decreased during chemoreceptor deactivation (control: -4.8±3.4%; AF: -5.1±3.0%; p<0.05), whereas heart rate did not change in AFHF patients. This resulted in impaired cardiac chemoreflex sensitivity in AFHF patients (1.9±1.6 vs. 0.5±1.2 ms/mmHg; p<0.05). In conclusion, our data suggest that tonic activation of excitatory chemoreceptor afferents contributes to a low vagal tone in heart failure patients with a history of AF (Clinical Trials NCT01262508).

Drexel T; Eickholt C; Mühlsteff J; Ritz A; Siekiera M; Kirmanoglou K; Schulze V; Shin DI; Balzer J; Rassaf T; Kelm M; Meyer C

2013-01-01

122

Vagal heart rate control in patients with atrial fibrillation: impact of tonic activation of peripheral chemosensory function in heart failure.  

Science.gov (United States)

Heart failure (HF) and atrial fibrillation (AF), emerging as two epidemics of the twenty-first century, are commonly associated with each other. Both have been mechanistically linked to changes in cardiac vagal control. The importance of peripheral chemosensors, located in the carotid body, has not been elucidated so far. We therefore investigated whether tonic activation of excitatory chemoreceptor afferents contributes to the altered vagal control in HF patients with a history of AF. In 18 patients (72 ±9 year, 7 male) with sinus rhythm and a history of AF (n=9, without any evidence of structural heart disease, AF group; n=9 with structural heart disease and clinical presentation of HF, AFHF group) we investigated the impact of chemosensory deactivation (by breathing 100% oxygen) on heart rate, blood pressure, cardiac output, total peripheral resistance, oxygen saturation and breathing rate. Ten healthy individuals served as a control group. In addition, we performed a deep breathing test demonstrating an impaired heart rate variation in patients with and without HF as compared with controls (expiration/inspiration difference: 23.9±6.9 vs. 6.9±6.1 bpm, and 23.9±6.9 vs. 7.8±4.8 bpm; p<0.05). In both control and AF groups, heart rate decreased during chemoreceptor deactivation (control: -4.8±3.4%; AF: -5.1±3.0%; p<0.05), whereas heart rate did not change in AFHF patients. This resulted in impaired cardiac chemoreflex sensitivity in AFHF patients (1.9±1.6 vs. 0.5±1.2 ms/mmHg; p<0.05). In conclusion, our data suggest that tonic activation of excitatory chemoreceptor afferents contributes to a low vagal tone in heart failure patients with a history of AF (Clinical Trials NCT01262508). PMID:22826079

Drexel, T; Eickholt, C; Mühlsteff, J; Ritz, A; Siekiera, M; Kirmanoglou, K; Schulze, V; Shin, D-I; Balzer, J; Rassaf, T; Kelm, M; Meyer, C

2013-01-01

123

Effect of retrobulbar nerve block on heart rate variability during enucleation in horses under general anesthesia.  

Science.gov (United States)

OBJECTIVE: Analysis of any effect of retrobulbar block during ocular surgery on heart rate variability and oculocardiac reflex. STUDY DESIGN: Prospective study. ANIMAL STUDIED: Horses (n = 16) undergoing eye enucleation due to chronic ophthalmologic diseases. PROCEDURE: Eye enucleation was performed under general anesthesia. The horses were randomly assigned to the first (inhalation anesthesia only, n = 10) or second group (inhalation and local retrobulbar anesthesia, n = 6). The retrobulbar block was performed using 12 mL of mepivacaine hydrochloride 2%. ECG data were taken by a Telemetric ECG before, during, and after surgery. Heart rate variability was analyzed in the time domain as mean heart rate, mean beat-to-beat interval duration, and standard deviation of continuous beat-to-beat intervals. The frequency domain analysis included the low- and high-frequency components of heart rate variability and the sympathovagal balance (low/high frequency). The low frequency represents mainly sympathetic influences on the heart, whereas high frequency is mediated by the parasympathetic tone. RESULTS: All horses without a retrobulbar block showed a significant decrease in the heart rate during traction on the globe and pressure on the orbital fat pad for homoestasis (P = 0.04). Simultaneously, high-frequency power, as an indicator of vagal stimulation, increased significantly. High-frequency and low-frequency power in the retrobulbar block group increased in five horses, and heart rate decreased in only one horse. Both were not significant within the group, but there was a significant difference between both groups relating to the incidence of heart rate decrease occurring at globe traction. CONCLUSIONS AND CLINICAL RELEVANCE: Heart rate variability is a sensitive, non-invasive parameter to obtain sympathovagal stimulations during general anesthesia. The retrobulbar block can prevent heart rate decrease associated with initiation of the oculocardiac reflex. PMID:23738675

Oel, Carolin; Gerhards, Hartmut; Gehlen, Heidrun

2013-06-01

124

Effect of retrobulbar nerve block on heart rate variability during enucleation in horses under general anesthesia.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Analysis of any effect of retrobulbar block during ocular surgery on heart rate variability and oculocardiac reflex. STUDY DESIGN: Prospective study. ANIMAL STUDIED: Horses (n = 16) undergoing eye enucleation due to chronic ophthalmologic diseases. PROCEDURE: Eye enucleation was performed under general anesthesia. The horses were randomly assigned to the first (inhalation anesthesia only, n = 10) or second group (inhalation and local retrobulbar anesthesia, n = 6). The retrobulbar block was performed using 12 mL of mepivacaine hydrochloride 2%. ECG data were taken by a Telemetric ECG before, during, and after surgery. Heart rate variability was analyzed in the time domain as mean heart rate, mean beat-to-beat interval duration, and standard deviation of continuous beat-to-beat intervals. The frequency domain analysis included the low- and high-frequency components of heart rate variability and the sympathovagal balance (low/high frequency). The low frequency represents mainly sympathetic influences on the heart, whereas high frequency is mediated by the parasympathetic tone. RESULTS: All horses without a retrobulbar block showed a significant decrease in the heart rate during traction on the globe and pressure on the orbital fat pad for homoestasis (P = 0.04). Simultaneously, high-frequency power, as an indicator of vagal stimulation, increased significantly. High-frequency and low-frequency power in the retrobulbar block group increased in five horses, and heart rate decreased in only one horse. Both were not significant within the group, but there was a significant difference between both groups relating to the incidence of heart rate decrease occurring at globe traction. CONCLUSIONS AND CLINICAL RELEVANCE: Heart rate variability is a sensitive, non-invasive parameter to obtain sympathovagal stimulations during general anesthesia. The retrobulbar block can prevent heart rate decrease associated with initiation of the oculocardiac reflex.

Oel C; Gerhards H; Gehlen H

2013-06-01

125

Statistical analysis of heart rate and heart rate variability monitoring through the use of smart phone cameras.  

UK PubMed Central (United Kingdom)

Video recordings of finger tips made using a smartphone camera contain a pulsatile component caused by the cardiac pulse equivalent to that present in a photoplethysmographic signal. By performing peak detection on the pulsatile signal it is possible to extract a continuous heart rate signal. We performed direct comparisons between 5-lead electrocardiogram based heart rate variability measurements and those obtained from an iPhone 4s and Motorola Droid derived pulsatile signal to determine the accuracy of heart rate variability measurements obtained from the smart phones. Monitoring was performed in the supine and tilt positions for independent iPhone 4s (2 min recordings, n=9) and Droid (5 min recordings, n=13) experiments, and the following heart rate and heart rate variability parameters were estimated: heart rate, low frequency power, high frequency power, ratio of low to high frequency power, standard deviation of the RR intervals, and root mean square of successive RR-differences. Results demonstrate that accurate heart rate variability parameters can be obtained from smart phone based measurements.

Bolkhovsky JB; Scully CG; Chon KH

2012-01-01

126

Depressed low frequency power of heart rate variability as an independent predictor of sudden death in chronic heart failure.  

UK PubMed Central (United Kingdom)

AIMS: Identification of patients with chronic heart failure at risk for sudden death remains difficult. We sought to assess the prognostic value for all-cause and sudden death of time and frequency domain measures of heart rate variability in chronic heart failure. METHODS AND RESULTS: We prospectively enrolled 190 patients with chronic heart failure in sinus rhythm, mean age 61+/-12 years, 109 (57.4%) in NYHA class II and 81 (42.6%) in classes III or IV, mean cardiothoracic ratio 57.6+/-6.4% and mean left ventricular ejection fraction 28.2+/-8.8%, 85 (45%) with ischaemic and 105 (55%) with idiopathic dilated cardiomyopathy. Time and frequency domain measures of heart rate variability were obtained from 24 h Holter ECG recordings, spectral measures were averaged for calculation of daytime (1000h-1900h) and night-time (2300h-0600h) values. During follow-up (22+/-18 months), 55 patients died, 21 of them suddenly and two presented with a syncopal spontaneous sustained ventricular tachycardia. In multivariate analysis, independent predictors for all-cause mortality were: ischaemic heart disease, cardiothoracic ratio > or =60% and standard deviation of all normal RR intervals <67 ms (RR = 2.5, 95% CI 1.5-4.2). Independent predictors of sudden death were: ischaemic heart disease and daytime low frequency power <3.3 ln (ms(2)) (RR = 2.8, 95% CI 1.2-8.6). CONCLUSION: Depressed heart rate variability has independent prognostic value in patients with chronic heart failure; spectral analysis identifies an increased risk for sudden death in these patients.

Galinier M; Pathak A; Fourcade J; Androdias C; Curnier D; Varnous S; Boveda S; Massabuau P; Fauvel M; Senard JM; Bounhoure JP

2000-03-01

127

Recurrence Plots of Heart Rate Signals during Meditation  

Directory of Open Access Journals (Sweden)

Full Text Available The current study analyses the dynamics of the heart rate signals during specific psychological states in order to obtain a detailed understanding of the heart rate patterns during meditation. In the proposed approach, heart rate time series available in Physionet database are used. The dynamics of the signals are then analyzed before and during meditation by examining the attractors in the phase space and recurrence quantification analysis. In general, the results reveal that the heart rate signals transit from a chaotic, highly-complex behavior before meditation to a low dimensional chaotic (and quasi-periodic) motion during meditation. This can be due to decreased nonlinear interaction of variables in meditation states and may be related to increased parasympathetic activity and increase of relaxation state. The results suggest that nonlinear chaotic indices may serve as a quantitative measure for psychophysiological states.

Ateke Goshvarpour; Atefeh Goshvarpour

2012-01-01

128

SCUBA-dive-related changes in heart rate in children.  

Science.gov (United States)

The purpose of this study was to monitor heart rate (HR) and rhythm during open water SCUBA dives. Nine children performed 25-min open water SCUBA dives to 8 m depth. Before, during and after these dives, ECG was recorded. Compared with predive heart rate, heart rate declined by -24 ± 8% (range -36%; -15%) during the dive. In some children a further decline in HR was observed within the last minutes of the dive. Older and taller subjects and those with a high initial HR showed a more pronounced decline in HR. Furthermore singular supraventricular and ventricular extrasystoles were observed in some children. Immersion as well as facial and skin cooling presumably account for the initial decline in heart rate. A further drop in HR within the last minutes of the dive might be related to mild hypothermia. Single supraventricular and ventricular extrasystoles might occur in healthy children during dives. PMID:21881159

Winkler, Bernd E; Tetzlaff, Kay; Muth, Claus-Martin; Paulat, Klaus; Hebestreit, Helge

2011-08-01

129

SCUBA-dive-related changes in heart rate in children.  

UK PubMed Central (United Kingdom)

The purpose of this study was to monitor heart rate (HR) and rhythm during open water SCUBA dives. Nine children performed 25-min open water SCUBA dives to 8 m depth. Before, during and after these dives, ECG was recorded. Compared with predive heart rate, heart rate declined by -24 ± 8% (range -36%; -15%) during the dive. In some children a further decline in HR was observed within the last minutes of the dive. Older and taller subjects and those with a high initial HR showed a more pronounced decline in HR. Furthermore singular supraventricular and ventricular extrasystoles were observed in some children. Immersion as well as facial and skin cooling presumably account for the initial decline in heart rate. A further drop in HR within the last minutes of the dive might be related to mild hypothermia. Single supraventricular and ventricular extrasystoles might occur in healthy children during dives.

Winkler BE; Tetzlaff K; Muth CM; Paulat K; Hebestreit H

2011-08-01

130

The fall in the rate of death from heart diseases  

International Nuclear Information System (INIS)

A self limiting interaction between heart disease producing factors and genetic factors is postulated. Such an interaction could be responsable for the fall in rate of death from ischemic disease observed in the United States. (Author)

1983-01-01

131

Change of Diurnal Heart Rate Patterns During Pregnancy and Lactation in Dogs (Canis familiaris)  

Directory of Open Access Journals (Sweden)

Full Text Available Pregnancy and lactation involve great demands on the cardiovascular system. The purpose of this study was to investigate how the heart rate and diurnal heart rate pattern change when dogs become pregnant or lactate. Five clinically healthy female beagle dogs were mated, and delivered three to seven healthy puppies. The heart rate was investigated with 24-h ECG (Holter) once during anoestrus, at 3, 5, 7 and 9 weeks of pregnancy, and at week 4 postpartum (lactation). However, at 9 weeks, the ECG could not be recorded for the fully 24 h in 4 of 5 dogs, because labour started and the dogs then appeared disturbed by the recordings. The results at this date are not included in the statistical comparison. The heart rate increased progressively during pregnancy and was still elevated at 4 weeks of lactation. During late pregnancy the difference in heart rates between daytime and nighttime became smaller, but the heart rate was significantly higher in daytime in all periods. In conclusion, the increased heart rates during pregnancy and lactation reflect increased demands on the cardiovascular system and may be important to consider in clinical practice.

Olsson K; Lagerstedt A-S; Bergström A; Häggström J

2003-01-01

132

Parental stethoscope use for infant heart rate counting.  

UK PubMed Central (United Kingdom)

Accurate measurement of an infant's heart rate by palpation or auscultation is challenging. (1,2,3,4,5) The standard of care for infant heart rate assessment by a healthcare professional is by apical auscultation using a stethoscope.(6,7,8) For the lay person, apical auscultation by ear to chest technique is often taught. This article is protected by copyright. All rights reserved.

McKillop SJ; Pepelassis D; Buffo Sequeira I

2013-06-01

133

Serum AChE Activities Predict Exercise Heart Rate Parameters of Asymptomatic Individuals  

Directory of Open Access Journals (Sweden)

Full Text Available Background specific heart rate parameters notably associate with variable risks of cardiovascular disease and mortal-ity, however, to date there are no readily available blood tests associated with these parameters. Because of the estab-lished parasympathetic contributions towards cardiac regulation, we challenged the working hypothesis that serum acetylcholinesterase (AChE) activity is involved. Methods A total of 403 Healthy men and women were included in the study and underwent treadmill exercise testing. Prior to exercise testing the subject’s serum AChE activity levels were assessed by measuring rates of acetylthiocholine hydrolysis. Results In male subjects AChE activity was positively cor-related to resting heart rate (r = 0.210, p = 0.001). Complementing this observation, AChE activity was negatively correlated to the exercise-induced heart rate increase (r = –0.181, p = 0.005) and to heart rate recovery at 1, 2 and 5 minutes following cessation of exercise (r = –0.150, p = 0.022; r = –0.157, p = 0.016; r = –0.176, p = 0.008 respec-tively). This indicated that lower than average AChE activities, which presumably reflect increased peripheral ACh levels, might be correlated to favorable heart rate parameters. Similar observations were made in female subjects, ex-cept for lack of correlation to their resting heart rate. Additionally, we observed that we were able to stratify subjects into two groups of significantly different AChE activity (p = 0.001) based on a cut point of heart rate recovery below 20 beats one minute after cessation of exercise. Conclusion In asymptomatic individuals lower than average AChE activity is associated with favorable indices of exercise-inducible heart rate increase as well as heart rate recovery. Future studies will be needed to evaluate the added prognostic significance gained by implementing this marker into routine practice.

Canaani Jonathan; Shenhar-Tsarfaty Shani; Weiskopf Nir; Yakobi Reut; Ben Assayag Einor; Berliner Shlomo; Soreq Hermona

2010-01-01

134

Heart rate variability analysis using a seismocardiogram signal.  

Science.gov (United States)

Seismocardiography is a simple and non invasive method of recording cardiac activity from the movements of the body caused by heart pumping. In this preliminary study we use a smartphone to record this acceleration and estimate the heart rate. We compare the heart rate variability parameters from the seismocardiogram and ECG reference signal. The results show a great similarity and are strongly influenced by the instability in the sampling frequency of the device. The differences between RR series are lower than 10 ms. PMID:23367209

Ramos-Castro, J; Moreno, J; Miranda-Vidal, H; García-González, M A; Fernández-Chimeno, Mireya; Rodas, G; Capdevila, Ll

2012-01-01

135

Maximal rate of increase in heart rate during the rest-exercise transition tracks reductions in exercise performance when training load is increased.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Heart rate kinetics are faster in well-trained athletes at exercise onset, indicating sensitivity to training status, but whether they track performance changes due to changes in training load is unknown. DESIGN: Randomised, counterbalanced, cross-over. METHODS: 17 cyclists completed two weeks of light and two weeks of heavy training. The day after each training period heart rate was recorded during 5min cycling at 100W to determine the maximal rate of heart rate increase. Participants then performed a 5min cycle time-trial after which heart rate recovery was determined. RESULTS: Work during 5min cycle time-trial decreased 3.5% (P<0.04) in participants (n=8) who increased training load (completed light training then heavy training) and, although maximal rate of heart rate increase did not change (P=0.27), within-individual changes in work were correlated with changes in maximal rate of heart rate increase (r=0.87, P=0.005). Work during 5min cycle time-trial increased 6.5% (P<0.001) in 9 participants who decreased training load (completed heavy training then light training) and maximal rate of heart rate increase increased 28% (P=0.002) but the changes in maximal work were not related to changes in rate of heart rate increase (r=0.32, P=0.40). Heart rate recovery tended to track changes in 5min cycle time-trial work following increases and decreases in training load (r=0.65-0.75, P=0.03-0.08). CONCLUSIONS: Maximal rate of heart rate increases during cycling at 100W tracks reductions in exercise performance when training load is increased, but not performance improvements when training loads are reduced. Maximal rate of heart rate increase may be a useful adjunct to heart rate recovery for tracking changes in exercise performance.

Nelson MJ; Thomson RL; Rogers DK; Howe PR; Buckley JD

2013-04-01

136

Match analysis and heart rate of futsal players during competition.  

UK PubMed Central (United Kingdom)

Heart rates were monitored and time-motion analysis performed for 10 players (mean age 25.6 years, s = 2.5; body mass 73.8 kg, s = 5.7 kg; height 1.75 m, s = 0.06) during four competitive futsal matches. Mean heart rate during the match was 90% (s = 2) of maximum heart rate. Heart rate records were classified based on the percentage of time spent in three zones (>85%, 85-65%, and <65% maximum heart rate); players spent 83%, 16%, and 0.3% in these three zones, respectively. During the second period, there was a significant reduction (P < 0.01) in the percentage of time spent at an intensity above 85% of maximum heart rate (first vs. second period: 86% vs. 79%). Players' movements were classified as standing, walking, jogging, medium-intensity running, high-intensity running, and sprinting (maximal speed running). Time-motion analysis indicated that the mean distance covered per minute of play was 117.3 m (s = 11.6), of which 28.5% (s = 2.2) was covered while performing medium-intensity running, 13.7% (s = 2) during high-intensity running, and 8.9% (s=3.4) while sprinting. From the results, we conclude that futsal is a multiple-sprints sport in which there are more high-intensity phases than in soccer and other intermittent sports.

Barbero-Alvarez JC; Soto VM; Barbero-Alvarez V; Granda-Vera J

2008-01-01

137

Reduced Heart Rate Variability in Social Anxiety Disorder: Associations with Gender and Symptom Severity  

Science.gov (United States)

Background Polyvagal theory emphasizes that autonomic nervous system functioning plays a key role in social behavior and emotion. The theory predicts that psychiatric disorders of social dysfunction are associated with reduced heart rate variability, an index of autonomic control, as well as social inhibition and avoidance. The purpose of this study was to examine whether heart rate variability was reduced in treatment-seeking patients diagnosed with social anxiety disorder, a disorder characterized by social fear and avoidance. Methods Social anxiety patients (n?=?53) were recruited prior to receiving psychological therapy. Healthy volunteers were recruited through the University of Sydney and the general community and were matched by gender and age (n?=?53). Heart rate variability was assessed during a five-minute recording at rest, with participants completing a range of self-report clinical symptom measures. Results Compared to controls, participants with social anxiety exhibited significant reductions across a number of heart rate variability measures. Reductions in heart rate variability were observed in females with social anxiety, compared to female controls, and in patients taking psychotropic medication compared to non-medicated patients. Finally, within the clinical group, we observed significant associations between reduced heart rate variability and increased social interaction anxiety, psychological distress, and harmful alcohol use. Conclusions The results of this study confirm that social anxiety disorder is associated with reduced heart rate variability. Resting state heart rate variability may therefore be considered a marker for social approach-related motivation and capacity for social engagement. Additionally, heart rate variability may provide a useful biomarker to explain underlying difficulties with social approach, impaired stress regulation, and behavioral inhibition, especially in disorders associated with significant impairments in these domains.

Alvares, Gail A.; Quintana, Daniel S.; Kemp, Andrew H.; Van Zwieten, Anita; Balleine, Bernard W.; Hickie, Ian B.; Guastella, Adam J.

2013-01-01

138

Parathyroidectomy and heart rate variability in patients with stage 5 CKD.  

UK PubMed Central (United Kingdom)

BACKGROUND AND OBJECTIVES: Lower heart rate variability implies increased risk of cardiovascular disease. This study aimed to evaluate the relationship between mineral metabolism and heart rate variability and longitudinal changes of heart rate variability after parathyroidectomy in stage 5 CKD patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This cross-sectional study included 118 stage 5 CKD patients, 87 controls, and a prospective study in two subgroups classified as successful (n=17) and unsuccessful (n=4) parathyroidectomy follow-up enrolled from March of 2011 to December of 2012. Blood examination and 24-hour Holter for heart rate variability were measured. RESULTS: Most heart rate variability indices were lower in stage 5 CKD patients. In multivariate stepwise regression models, serum intact parathyroid hormone was correlated with mean normal-to-normal R-R intervals, mean heart rate, and very low frequency, serum calcium was correlated with SD of 5-minute average of normal R-R intervals, and serum phosphorus was correlated with very low frequency and low frequency/high frequency. Compared with baseline, the successful parathyroidectomy subgroup had significant improvements in mean normal-to-normal R-R intervals, mean heart rate, SD of normal-to-normal R-R intervals, SD of 5-minute average of normal R-R intervals, very low frequency, high frequency, and low frequency/high frequency. There was no significant change of heart rate variability in patients after unsuccessful parathyroidectomy. CONCLUSIONS: Disorders of mineral metabolism are associated with decreased heart rate variability in stage 5 CKD. Successful parathyroidectomy may contribute to reverse this cardiovascular disease risk in severe secondary hyperparathyroidism patients.

Zhang J; Yu X; Sun B; Bai J; Wei Y; Zha X; Cui Y; Zeng M; Zhang J; Liu J; Mao H; Zhang B; Ren H; Ge Y; Xu X; Shen Z; Xing C; Cao K; Wang N

2013-08-01

139

Reduced heart rate variability in social anxiety disorder: associations with gender and symptom severity.  

UK PubMed Central (United Kingdom)

BACKGROUND: Polyvagal theory emphasizes that autonomic nervous system functioning plays a key role in social behavior and emotion. The theory predicts that psychiatric disorders of social dysfunction are associated with reduced heart rate variability, an index of autonomic control, as well as social inhibition and avoidance. The purpose of this study was to examine whether heart rate variability was reduced in treatment-seeking patients diagnosed with social anxiety disorder, a disorder characterized by social fear and avoidance. METHODS: Social anxiety patients (n?=?53) were recruited prior to receiving psychological therapy. Healthy volunteers were recruited through the University of Sydney and the general community and were matched by gender and age (n?=?53). Heart rate variability was assessed during a five-minute recording at rest, with participants completing a range of self-report clinical symptom measures. RESULTS: Compared to controls, participants with social anxiety exhibited significant reductions across a number of heart rate variability measures. Reductions in heart rate variability were observed in females with social anxiety, compared to female controls, and in patients taking psychotropic medication compared to non-medicated patients. Finally, within the clinical group, we observed significant associations between reduced heart rate variability and increased social interaction anxiety, psychological distress, and harmful alcohol use. CONCLUSIONS: The results of this study confirm that social anxiety disorder is associated with reduced heart rate variability. Resting state heart rate variability may therefore be considered a marker for social approach-related motivation and capacity for social engagement. Additionally, heart rate variability may provide a useful biomarker to explain underlying difficulties with social approach, impaired stress regulation, and behavioral inhibition, especially in disorders associated with significant impairments in these domains.

Alvares GA; Quintana DS; Kemp AH; Van Zwieten A; Balleine BW; Hickie IB; Guastella AJ

2013-01-01

140

Differences in heart rate profile during exercise among subjects with subclinical thyroid disease.  

Science.gov (United States)

Background: Clinical thyroid disease is associated with changes in the cardiovascular system, including changes in heart rate during exercise. However, data on the relation between subclinical thyroid disease (SCTD) and heart rate during exercise are limited. Methods: We investigated 3799 apparently healthy subjects who were evaluated in the Institute for Preventive Medicine at the Sheba Medical Center. All subjects answered standard health questionnaires; were examined by a physician; completed routine blood tests including thyrotropin, free triiodothyronine, and free thyroxine levels; and underwent a treadmill exercise according to the Bruce protocol. Subjects with known thyroid disease or those who were taking thyroid-related drugs were excluded from the analysis. Heart rate profile was compared between patients with subclinical hypothyroidism (SCHypoT), patients with normal thyroid function, and patients with subclinical hyperthyroidism (SCHyperT) using propensity score matching. Results: Seventy patients had SCHyperT and 273 had SCHypoT. Compared with age- and sex-matched normal subjects, SCHyperT subjects had a higher resting heart rate (83±17 vs. 76±12 beats per minute [bpm], p=0.006), a significantly higher recovery heart rate (94±12 vs. 90±12?bpm, p=0.045), and a significantly lower heart rate reserve (80±20 vs. 87±18?bpm, p=0.006). Subjects with SCHypoT showed a trend toward a lower resting heart rate (75±13 vs. 77±15?bpm, p=0.09) and had a significantly lower recovery heart rate (88±12 vs. 90±13?bpm, p=0.035). There was no significant difference in exercise duration or blood pressure between subjects with SCTD and their matched normal controls. Conclusions: Subjects with SCTD have a significantly different heart rate profile during rest, exercise, and recovery. PMID:23777550

Maor, Elad; Kivity, Shaye; Kopel, Eran; Segev, Shlomo; Sidi, Yechezkel; Goldenberg, Ilan; Olchovsky, David

2013-09-14

 
 
 
 
141

A combined heart rate and movement sensor: proof of concept and preliminary testing study.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Heart rate monitoring has previously been used as a technique for measuring energy expenditure (EE) in field studies. However, the combination of heart rate monitoring with movement sensoring could have theoretical advantages compared to either method used alone. Therefore, this study was undertaken to develop and validate a new combined heart rate monitor and movement sensor instrument (HR+M) for measuring EE. METHODS: The HR+M instrument is a single-piece instrument worn around the chest which records minute-by-minute heart rate and movement. Eight subjects underwent an individual calibration in which EE and heart rate were measured at rest and during a sub-maximal bicycle ergometer test. They then wore the HR+M for 24 hours in a whole-body calorimeter and underwent a standard protocol including periods of physical activity and inactivity. Minute-by-minute heart rate was converted to EE using individual calibration curves with the motion data discriminating between periods of inactivity and activity at low heart rate levels. EE was also calculated using the HRFlex method which relies on heart rate alone. Both estimates of EE were compared to EE measured in the whole-body calorimeter. RESULTS: The mean percentage error of the HR+M method calculating TEE compared with the gold standard of the calorimeter measurement was 0.00% (95% CI of the mean error -0.25, 1. 25). The HRFlex method using the heart rate information alone resulted in a mean percentage error of 16.5% (95% CI of the mean error -0.57, 1.76). CONCLUSIONS: This preliminary test of HR+M demonstrates its ability to estimate EE and the pattern of EE and activity throughout the day. Further validation studies in free-living individuals are necessary. SPONSORSHIP: NJW is an MRC Clinician Scientist Fellow. KLR holds an MRC PhD scholarship.

Rennie K; Rowsell T; Jebb SA; Holburn D; Wareham NJ

2000-05-01

142

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

Science.gov (United States)

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. PMID:23143989

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

2012-11-09

143

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

UK PubMed Central (United Kingdom)

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.

Munsters CC; de Gooijer JW; van den Broek J; van Oldruitenborgh-Oosterbaan MM

2013-01-01

144

Heart rate variability during sleep in detoxified alcohol-dependent males: A comparison with healthy controls.  

UK PubMed Central (United Kingdom)

CONTEXT: Alcohol dependence can lead to autonomic neuropathy resulting in increased cardiac morbidity and mortality. This has previously been evaluated using heart-rate variability. AIMS: We compared sleep heart-rate variability of alcohol-dependent patients with that of healthy controls in this study. SETTINGS AND DESIGN: This study was conducted at NIMHANS, Bangalore. A case control study design was adopted. MATERIALS AND METHODS: Sleep heart-rate variability of 20 male alcohol-dependent inpatients was recorded on the 5(th) day after detoxification. Sleep heart-rate variability was also recorded in 18 age- and gender-matched healthy controls. STATISTICAL ANALYSIS: The groups were compared using t-test for continuous variables and Chi-squared test for discrete variables. RESULTS: Both time and frequency domain measures were significantly lower in the patients as compared to the controls, indicating decreased HRV in alcohol-dependent individuals. CONCLUSIONS: Decreased HRV in alcohol dependence indicates potential autonomic neuropathy.

Ganesha S; Thirthalli J; Muralidharan K; Benegal V; Gangadhar BN

2013-04-01

145

Both right and left cervical cordotomies depress sympathetic indexes derived from heart rate variability in humans.  

UK PubMed Central (United Kingdom)

Unilateral percutaneous cervical cordotomy, performed in humans to relieve intractable cancer pain, elicits signs of ipsilateral sympathetic block. In patients undergoing right or left percutaneous cervical cordotomy (9 per group), changes in sympathovagal balance were evaluated by spectral analysis of heart rate to confirm the sympatholytic effect of this surgical procedure and to investigate the lateralization of sympathetic cardiac control. For these purposes, heart rate variability was recorded 1 hour before cordotomy and 24 hours later. Cordotomy significantly depressed the low frequency peak (LF) of heart rate variability and increased the high frequency component (HF), when measured as a percentage of total power. As a consequence, the LF/HF ratio decreased significantly (P =.001), particularly during standing. The effects of right or left cordotomies were not significantly different. In conclusion, in humans unilateral percutaneous cervical cordotomy depresses some sympathetic indexes (LF/total power ratio and LF/HF ratio) derived from heart rate variability, irrespective of side.

Verlato G; Polati E; Speranza G; Finco G; Gottin L; Ischia S

2001-10-01

146

Effect of immersion, submersion, and scuba diving on heart rate variability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background—Heart rate variability (HRV) describes the cyclic variations in heart rate and offers a non-invasive tool for investigating the modulatory effects of neural mechanisms elicited by the autonomic nervous system on intrinsic heart rate.

Schipke, J; Pelzer, M

147

Heart rate: a prognostic factor and therapeutic target in chronic heart failure. The distinct roles of drugs with heart rate-lowering properties.  

UK PubMed Central (United Kingdom)

Heart rate not only predicts outcome but may also be a therapeutic target in patients with chronic heart failure. Several classes of pharmacological agents can be used to modulate heart rate, including beta-blockers, ivabradine, digoxin, amiodarone, and verapamil. Choice of agent will depend on heart rhythm, co-morbidities, and disease phenotype. Beneficial and harmful interactions may also exist. The aim of this paper is to summarize the current body of knowledge regarding the relevance of heart rate as a prognostic factor (risk marker) and particularly as a therapeutic target (risk factor) in patients with chronic heart failure, with a special focus on ivabradine, a novel agent that is currently the only available purely bradycardic agent.

Dobre D; Borer JS; Fox K; Swedberg K; Adams KF; Cleland JG; Cohen-Solal A; Gheorghiade M; Gueyffier F; O'Connor CM; Fiuzat M; Patak A; Piña IL; Rosano G; Sabbah HN; Tavazzi L; Zannad F

2013-08-01

148

The effect of altering heart rate on ventricular function in patients with heart failure treated with beta-blockers.  

UK PubMed Central (United Kingdom)

BACKGROUND: Beta-blockers are effective for the treatment of heart failure, but their mechanism of action is unresolved. Heart rate reduction may be a central mechanism or a troublesome side effect. METHODS: A randomized, double-blind, parallel group study comparing chronic higher-rate (80 pulses per minute) with lower-rate (60 pulses per minute) pacing in pacemaker-dependent patients with symptomatic left ventricular (LV) systolic dysfunction, receiving beta-blockers. Gated radionuclide ventriculography (RNVG) was performed at baseline and after at least 9 months. The primary outcome was change in LV volumes, as a marker of beneficial reverse remodeling, from baseline to follow-up. RESULTS: Forty-nine patients were randomized. Mean age was 74 +/- 6 years and with LV ejection fraction of 26% +/- 9% at baseline. During 14 +/- 13 months of follow-up, 21 patients (43%) died and 25 (51%) completed the study protocol: 12 in the higher-rate and 13 in the lower-rate group. Mean LV end-diastolic (higher rate +20 +/- 104 mL vs lower rate -65 +/- 92 mL, P = .03) and systolic (higher rate +29 +/- 83 mL vs lower rate -60 +/- 74 mL, P = .006) volumes increased with higher-rate versus lower-rate pacing, whereas LV ejection fraction declined (higher rate -4.2% +/- 4.4% vs lower rate +2.2% +/- 5.4%, P = .002). CONCLUSION: Reversal of beta-blocker-induced bradycardia has deleterious effects on ventricular function, suggesting heart rate reduction is an important mediator of their effects. The prognosis of patients with pacemakers and heart failure is poor.

Thackray SD; Ghosh JM; Wright GA; Witte KK; Nikitin NP; Kaye GC; Clark AL; Tweddel A; Cleland JG

2006-10-01

149

The heart field effect: Synchronization of healer-subject heart rates in energy therapy.  

Science.gov (United States)

Recent health research has focused on subtle energy and vibrational frequency as key components of health and healing. In particular, intentional direction of bioenergy is receiving increasing scientific attention. This study investigates the effect of the healer's electromagnetic (EM) heart field upon subjects during energy healing as measured by synchronization of heart rates and scores on a Subjective Units of Distress (SUD) scale and a Profile of Mood States (POMS) inventory. A nonequivalent pretest-posttest design was used based on heart rate comparisons between healer and subject and correlated with pre-and posttest SUD and POMS scores. Subjects included those who sat within the 3- to 4-foot "strong" range of the independent variable, the healer's heart field, while performing self-application of WHEE (the wholistic hybrid derived from EMDR [eye movement desensitization and reprocessing], and EFT [emotional freedom technique]), a meridian-based tapping technique (n=50); and those who performed the same process beyond the 15- to 18-foot range of the healer's EM heart field (n=41). The dependent variables were heart rate, SUD, and POMS inventory. All subjects completed these measures within 1 hour. Study results showed statistically significant heart-rate synchronization with the intervention population. In addition, SUD and POMS scores demonstrated considerably more improvement than in the control population, indicating additional benefit beyond the meridian-based therapies, such as WHEE, alone. Additional findings and future research recommendations are presented in this article. PMID:20664147

Bair, Christine Caldwell

2008-01-01

150

Effect of bucindolol on heart failure outcomes and heart rate response in patients with reduced ejection fraction heart failure and atrial fibrillation.  

UK PubMed Central (United Kingdom)

AIMS: There is little evidence of beta-blocker treatment benefit in patients with heart failure and reduced left ventricular ejection fraction (HFREF) and atrial fibrillation (AF). We investigated the effects of bucindolol in HFREF patients with AF enrolled in the Beta-blocker Evaluation of Survival Trial (BEST). METHODS AND RESULTS: A post-hoc analysis of patients in BEST with and without AF was performed to estimate the effect of bucindolol on mortality and hospitalization. Patients were also evaluated for treatment effects on heart rate and the influence of beta1-adrenergic receptor position 389 (?(1)389) arginine (Arg) vs. glycine (Gly) genotypes. In the 303/2708 patients in AF, patients receiving bucindolol were more likely to achieve a resting heart rate ? 80 b.p.m. at 3 months (P < 0.005) in the absence of treatment-limiting bradycardia. In AF patients and sinus rhythm (SR) patients who achieved a resting heart rate ? 80 b.p.m., there were beneficial treatment effects on cardiovascular mortality/cardiovascular hospitalization [hazard ratio (HR) 0.61, P = 0.025, and 0.79, P = 0.002]. Without achieving a resting heart rate ? 80 b.p.m., there were no treatment effects on events in either group. ?(1)389-Arg/Arg AF patients had nominally significant reductions in all-cause mortality/HF hospitalization and cardiovascular mortality/hospitalization with bucindolol (HR 0.23, P = 0.037 and 0.28, P = 0.039), whereas Gly carriers did not. There was no evidence of diminished heart rate response in ?(1)389-Arg homozygotes. CONCLUSION: In HFREF patients with AF, bucindolol was associated with reductions in composite HF endpoints in those who achieved a resting heart rate ? 80 b.p.m. and nominally in those with the ?(1)389-Arg homozygous genotype.

Kao DP; Davis G; Aleong R; O'Connor CM; Fiuzat M; Carson PE; Anand IS; Plehn JF; Gottlieb SS; Silver MA; Lindenfeld J; Miller AB; White M; Murphy GA; Sauer W; Bristow MR

2013-03-01

151

Heart rate at baseline influences the effect of ivabradine on cardiovascular outcomes in chronic heart failure: analysis from the SHIFT study.  

UK PubMed Central (United Kingdom)

BACKGROUND: We analysed the effect of ivabradine on outcomes in heart failure (HF) patients on recommended background therapies with heart rates ?75 bpm and <75 bpm in the SHIFT trial. A cut-off value of ?75 bpm was chosen by the EMEA for approval for the use of ivabradine in chronic heart failure. METHODS: The SHIFT population was divided by baseline heart rate ?75 or <75 bpm. The effect of ivabradine was analysed for primary composite endpoint (cardiovascular death or HF hospitalization) and other endpoints. RESULTS: In the ?75 bpm group, ivabradine reduced primary endpoint (HR 0.76, 95 % CI 0.68-0.85, P < 0.0001), all-cause mortality (HR 0.83, 95 % CI, 0.72-0.96, P = 0.0109), cardiovascular mortality (HR 0.83, 95 % CI, (0.71-0.97, P = 0.0166), HF death (HR 0.61, 95 % CI, 0.46-0.81, P < 0.0006), and HF hospitalization (HR 0.70, 95 % CI, 0.61-0.80, P < 0.0001). Risk reduction depended on heart rate after 28 days, with the best protection for heart rates <60 bpm or reductions >10 bpm. None of the endpoints was significantly reduced in the <75 bpm group, though there were trends for risk reductions in HF death and hospitalization for heart rate <60 bpm and reductions >10 bpm. Ivabradine was tolerated similarly in both groups. CONCLUSION: The effect of ivabradine on outcomes is greater in patients with heart rate ?75 bpm with heart rates achieved <60 bpm or heart rate reductions >10 bpm predicting best risk reduction. Our findings emphasize the importance of identification of high-risk HF patients by high heart rates and their treatment with heart rate-lowering drugs such as ivabradine.

Böhm M; Borer J; Ford I; Gonzalez-Juanatey JR; Komajda M; Lopez-Sendon J; Reil JC; Swedberg K; Tavazzi L

2013-01-01

152

Cuff inflation during ambulatory blood pressure monitoring and heart rate  

Directory of Open Access Journals (Sweden)

Full Text Available Mia Skov-Madsen, My Svensson, Jeppe Hagstrup ChristensenDepartment of Nephrology, Aarhus University Hospital, Aalborg, DenmarkIntroduction: Twenty four-hour ambulatory blood pressure monitoring is a clinically validated procedure in evaluation of blood pressure (BP). We hypothesised that the discomfort during cuff inflation would increase the heart rate (HR) measured with 24-h ambulatory BP monitoring compared to a following HR measurement with a 24-h Holter monitor.Methods: The study population (n = 56) were recruited from the outpatient’s clinic at the Department of Nephrology, Aalborg Hospital, Aarhus University Hospital at Aalborg, Denmark. All the patients had chronic kidney disease (CKD). We compared HR measured with a 24-h Holter monitor with a following HR measured by a 24-h ambulatory BP monitoring.Results: We found a highly significant correlation between the HR measured with the Holter monitor and HR measured with 24-h ambulatory blood pressure monitoring (r = 0.77, p < 0.001). Using the Bland-Altman plot, the mean difference in HR was only 0.5 beat/min during 24 hours with acceptable limits of agreement for both high and low HR levels. Dividing the patients into groups according to betablocker treatment, body mass index, age, sex, angiotensin-converting enzyme inhibitor treatment, statins treatment, diuretic treatment, or calcium channel blocker treatment revealed similar results as described above.Conclusion: The results indicate that the discomfort induced by cuff inflation during 24-h ambulatory BP monitoring does not increase HR. Thus, 24-h ambulatory BP monitoring may be a reliable measurement of the BP among people with CKD.Keywords: ambulatory blood pressure monitoring, Holter monitoring, heart rate, chronic kidney disease, hypertension

Mia Skov-Madsen; My Svensson; Jeppe Hagstrup Christensen

2008-01-01

153

Neonatal heart rate variability and its relation to respiration.  

UK PubMed Central (United Kingdom)

The heart rate and respiration signals from nine healthy full term neonates were studied using autoregressive spectral analysis and cross-correlation techniques. The heart rate spectra could be divided into three regions of activity: a very low frequency (VLF) region from 0-0.04 Hz; a low frequency (LF) band from 0.04-0.20 Hz; and a high frequency (HF) region above 0.20 Hz. The newborns exhibited very little respiratory sinus arrhythmia in their heart rate variability in contrast to the situation for adults and older infants. However, variations in heart rate correlated strongly with changes in the breath amplitude, leading to what may be termed a breath amplitude sinus arrhythmia. The neonatal heart rate behaviour under stable conditions of oscillation could be simulated with a nonlinear control model provided the delay time in the baroreceptor loop of the model was taken to be approximately 2 seconds longer than in adults. This is consistent with the immature neurological status of neonates.

Giddens DP; Kitney RI

1985-04-01

154

AUTONOMIC CONTROL OF HEART RATE AFTER EXERCISE IN TRAINED WRESTLERS  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Carlos F Henríquez; Eduardo Báez; Astrid Von Oetinger; Rodrigo Cañas; Rodrigo Ramírez

2013-01-01

155

Heart rate variability in complex regional pain syndrome during rest and mental and orthostatic stress.  

UK PubMed Central (United Kingdom)

BACKGROUND: Complex regional pain syndrome (CRPS) is a pain condition with regional sensory and autonomic abnormalities in the affected limb. The authors studied systemic autonomic and hemodynamic function in CRPS patients during rest, and during orthostatic and mental arithmetic stress. METHODS: Twenty patients with CRPS and 20 age-, sex-, and body mass index-matched control subjects participated. Mean values of heart rate variability, baroreceptor sensitivity, blood pressure, stroke volume, cardiac output, and total peripheral resistance were estimated during supine rest and 60° tilt-table testing. On a separate day, heart rate variability was also measured during mental arithmetic stress testing induced by a paced auditory serial addition task. RESULTS: Heart rate was increased and heart rate variability reduced in patients with CRPS patients compared with control subjects during rest and mental and orthostatic stress, whereas baroreceptor sensitivity was unaffected. When tilted from supine to upright position, patients with CRPS were not able to preserve cardiac output in comparison with control subjects, and they exhibited an exaggerated increase in the total peripheral resistance. The hemodynamic changes correlated to pain duration but not to pain intensity. CONCLUSION: The increased heart rate and decreased heart rate variability in CRPS suggest a general autonomic imbalance, which is an independent predictor for increased mortality and sudden death. The inability of the patients to protect their cardiac output during orthostatic stress was aggravated with the chronicity of the disease.

Terkelsen AJ; Mølgaard H; Hansen J; Finnerup NB; Krøner K; Jensen TS

2012-01-01

156

Predicted Heart Rate Effect of Inhaled LABA PF-00610355 in volunteers and COPD patients.  

Science.gov (United States)

AIM: To assess the cardiovascular effects of a new inhaled long-acting beta agonist PF-00610355 in COPD Patients. METHODS: 13,062 heart rate measurements collected in 10 clinical studies from 579 healthy volunteers, asthma, and COPD patients, were analyzed. The relationship between heart rate profiles and predicted plasma concentration profiles, patient status, demographics, and concomitant medication was evaluated using non-linear mixed-effects models. The median heart rate increase in COPD patients for doses of PF-00610355 up to 280 ?g QD was simulated with the final pharmacokinetics/pharmacodynamics (PKPD) model. RESULTS: An EMAX model accounting for delayed on- and offset of the PF-00610355-induced change in heart rate was developed. The predicted potency in COPD patients was 3-fold lower compared to healthy volunteers, while no difference in maximum drug effect was identified. Simulations suggested a maximum placebo-corrected increase of 2.7 (0.90-4.82) bpm in COPD patients for a PF-00610355 dose of 280 ?g QD, with 19% subjects experiencing a heart rate increase of more than 20 bpm compared to 8% in the placebo group. CONCLUSIONS: This PKPD analysis supports the clinical observation that no relevant effects of PF-00610355 on heart rate in COPD patients should be expected for doses up to 280 ?g QD. PMID:23323609

Diderichsen, Paul Matthias; Cox, Eugène; Martin, Steven W; Cleton, Adriaan; Ribbing, Jakob

2013-01-17

157

The effect of competition on heart rate during kart driving: A field study  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Both the act of competing, which can create a kind of mental stress, and participation in motor sports, which induces physical stress from intense g-forces, are known to increase heart rate dramatically. However, little is known about the specific effect of competition on heart rate during motor sports, particularly during four-wheel car driving. The goal of this preliminary study, therefore, was to investigate whether competition increases heart rate under such situations. Findings The participants drove an entry-level formula kart during two competitive races and during solo driving against the clock while heart rate and g-forces were measured. Analyses showed that heart rate values during the races (168.8 beats/min) were significantly higher than those during solo driving (140.9 beats/min) and rest (75.1 beats/min). Conclusions The results of this preliminary study indicate that competition heightens heart rate during four-wheel car driving. Kart drivers should be concerned about maintaining good health and developing physical strength.

Matsumura Kenta; Yamakoshi Takehiro; Yamakoshi Yasuhiro; Rolfe Peter

2011-01-01

158

Heart Rate Variability in Complex Regional Pain Syndrome during Rest and Mental and Orthostatic Stress  

DEFF Research Database (Denmark)

BACKGROUND:: Complex regional pain syndrome (CRPS) is a pain condition with regional sensory and autonomic abnormalities in the affected limb. The authors studied systemic autonomic and hemodynamic function in CRPS patients during rest, and during orthostatic and mental arithmetic stress. METHODS:: Twenty patients with CRPS and 20 age-, sex-, and body mass index-matched control subjects participated. Mean values of heart rate variability, baroreceptor sensitivity, blood pressure, stroke volume, cardiac output, and total peripheral resistance were estimated during supine rest and 60° tilt-table testing. On a separate day, heart rate variability was also measured during mental arithmetic stress testing induced by a paced auditory serial addition task. RESULTS:: Heart rate was increased and heart rate variability reduced in patients with CRPS patients compared with control subjects during rest and mental and orthostatic stress, whereas baroreceptor sensitivity was unaffected. When tilted from supine to upright position, patients with CRPS were not able to preserve cardiac output in comparison with control subjects, and they exhibited an exaggerated increase in the total peripheral resistance. The hemodynamic changes correlated to pain duration but not to pain intensity. CONCLUSIONS:: The increased heart rate and decreased heart rate variability in CRPS suggest a general autonomic imbalance, which is an independent predictor for increased mortality and sudden death. The inability of the patients to protect their cardiac output during orthostatic stress was aggravated with the chronicity of the disease.

Terkelsen, Astrid J; MØlgaard, Henning

2012-01-01

159

Kramers-Moyal Expansion of Heart Rate Variability  

International Nuclear Information System (INIS)

The first six Kramers-Moyal coefficients were extracted from human heart rate variability recordings. The method requires the determination of the Markov time and of the proper conditional probability densities. We analyzed heart rate data recorded in a group of ten young, healthy subjects. We obtained non-negligible higher order Kramers-Moyal (K-M) terms in 6 h nighttime parts of the 24 h recordings. This indicates that the data is a non-Gaussian process and probably a correlated signal. The analysis yielded important new insights into the character and distribution of the stochastic processes measured in healthy group. In the night hours, the dominant oscillation in the heart rate is the so called respiratory sinus arrhythmia (RSA)-a physiological phenomenon in which respiration acts as a drive for the heart rate. Certain kinds of pathology may disrupt RSA. We compared nighttime recordings of the healthy group with those recorded in six patients with hypertrophic cardiomyopathy (HCM). HCM is generally a pathology of heart cells but abnormalities in autonomic regulation are also observed. Using the higher order Kramers-Moyal coefficients, we analyzed the skewness and kurtosis in the nighttime recordings for the normal subjects. (author)

2009-01-01

160

Effects of smoking on heart rate at rest and during exercise, and on heart rate recovery, in young adults.  

UK PubMed Central (United Kingdom)

INTRODUCTION: There is an established link between smoking, abnormal heart rate (HR) values, and impaired cardiovascular health in middle-aged or older populations. The purpose of this study was to examine the effects of smoking on resting HR and on HR responses during and after exercise in young adults. METHODS: A sample of 298 young adults (159 men), aged 20-29 years old, were selected from a large population of health-science students based on health status, body mass index, physical activity, and smoking habit. All subjects underwent a maximal Bruce treadmill test and their HR was recorded during, at peak, and after termination of exercise. RESULTS: Smokers had significantly higher resting HR values than non-smokers. Both female and male smokers showed a significantly slower HR increase during exercise. Female smokers failed to reach their age-predicted maximum HR by 6.0 bpm and males by 3.6 bpm. The actual maximum HR achieved (HRmax) was significantly lower for both female smokers (191.0 bpm vs.198.0 bpm) and male smokers (193.2 bpm vs.199.3 bpm), compared to non-smokers. Heart rate reserve was also significantly lower in female (114.6 bpm vs. 128.1 bpm) and male smokers (120.4 bpm vs. 133.0 bpm). During recovery, the HR decline was significantly attenuated, but only in female smokers. Females had a higher resting HR and showed a higher HR response during sub-maximal exercise compared to males. CONCLUSIONS: Smoking was found to affect young smokers' HR, increasing HR at rest, slowing HR increase during exercise and impairing their ability to reach the age-predicted HRmax. In addition, smoking was associated with an attenuated HR decline during recovery, but only in females.

Papathanasiou G; Georgakopoulos D; Papageorgiou E; Zerva E; Michalis L; Kalfakakou V; Evangelou A

2013-05-01

 
 
 
 
161

The Effect of Valsartan on Heart Rate Variability and Heart Rate Recovery in Patients with Mild to Moderate Mitral Stenosis  

Directory of Open Access Journals (Sweden)

Full Text Available Summary: Atrial fibrillation (AF) is known to be one of the most important complications of mitral stenosis (MS). It has been reported that autonomic nervous system (ANS) had an effect on AF development, heart rate variability (HRV) and heart rate recovery (HRR) were under the control of ANS, and their disorders were present in MS. We studied the effect of Valsartan on HRV and HRT, and thus its effect on ANS. Methods: Eleven patients (39±8 years, 10 females) with mild to moderate MS were included in the study. Sixteen volunteers (38±8 years, 14 females) matched for age and sex were selected for control group. All subjects underwent transthoracic echocardiography (TTE), symptom-limited treadmill test and 24 hour Holter monitorization.The patients were administered 160 mg of Valsartan daily for 14 weeks. TTE, treadmill test and Holter monitorization were repeated at the end of treatment period. In Holter monitorization, the time and frequency domain analysis of HRV and in exercise test, HRR at first and third minutes (HRR1 and HRR3) were examined. Results: Before Valsartan treatment, no significant difference was found in HRR and HRV parameters between the two groups. Systolic and diastolic blood pressure, and also HRR1values were significantly decreased after treatment of Valsartan (117±6 vs. 107±4 mmHg p<0.002, 76±6 vs. 69±9 mmHg p<0.044, 44±14 vs. 33±12 p< 0.014, respectively), while the exercise time was significantly increased (786±114 vs. 846±95 sn p< 0.044). In Holter analysis neither time nor frequency domain of HRV parameters showed a meaningful change. Conclusion: In moderate MS, treatment with Valsartan improved the effort capacity, while autonomic function parameters have been defined on the base of HRV and HRR were not significantly different.

Hekim Karap?nar; Özlem Batukan Esen; Mustafa Akçakoyun; Göksel Açar; Selçuk Pala; Ramazan Karg?n; Hasan Kaya; Anil Avc?; Cevat K?rma; Ali Metin Esen

2010-01-01

162

Spectral analysis of heart rate variability of lizard, Gallotia galloti.  

UK PubMed Central (United Kingdom)

The beat-to-beat heart rate of the lizard, Gallotia galloti, at rest shows short-term oscillations, the frequency of which varies with body temperature. Spectral analysis of the heart rate variability signal shows that, above 20 degrees C, two major frequency components are present: the first component has a mean frequency ranging from 0.032 at 20 degrees C to 0.070 Hz at 35 degrees C and the second from 0.039 at 20 degrees C to 0.10 Hz at 35 degrees C of body temperature. The beat-to-beat heart rate variability does not seem to be correlated with ventilatory activity. The two spectral components could be associated as in mammals with the activity of the control systems that regulate the circulation, especially with the cutaneous vasomotor thermoregulatory and endogenous pressure vasomotor activities. Transient interactions between both components are described.

Gonzalez Gonzalez J; De Vera Porcell L

1988-02-01

163

Estimating sleep disordered breathing based on heart rate analysis.  

UK PubMed Central (United Kingdom)

Heart rate variability and the analysis of the ECG with ECG derived respiration has been used to diagnose sleep disordered breathing. Recently it was possible to distinguish obstructive sleep apnea and central sleep apnea. This can be achieved by analyzing both, heart rate variability and the more mechanically induced ECG derived respiration in parallel. In addition the analysis of cardiopulmonary coupling facilitates to predict the personal risk factor for cardiovascular disorders. The analysis of heart rate, ECG and respiration goes beyond this analysis. Some studies indicate that it is possible to derive sleep stages from these signals. In order to derive sleep stages a more complex analysis of the signals is applied taking into account non-linear properties by using methods of statistical physics. To extract coupling information supports the distinction between sleep stages. Results are reported in this review.

Penzel T; Glos M; Schobel C; Lal S; Fietze I

2013-07-01

164

Stability of heart rate variability indices reflecting parasympathetic activity.  

UK PubMed Central (United Kingdom)

Heart rate variability (HRV) is a measure of autonomic influences on heart rate that has frequently been used as a transsituationally consistent biomarker for cardiovascular health and emotional or cognitive functions. The psychometric properties of HRV however remain unclear. In the present study, we examined the reliability and temporal stability of parasympathetic HRV measures and estimated the portion of variance explained by transsituationally consistent trait variance and by effects of the situation and person-situation interaction with structural equation modeling. The results show good reliability of indices reflecting central parasympathetic control over heart rate and that about 40% of the variance of a single HRV measurement can be explained by effects of the situation and person-situation interaction. An aggregation across at least two measurements may be recommended when using HRV as a transsituationally consistent biomarker or trait.

Bertsch K; Hagemann D; Naumann E; Schächinger H; Schulz A

2012-05-01

165

Impaired heart rate recovery in patients with endemic fluorosis.  

UK PubMed Central (United Kingdom)

The objective of the present study was to determine the heart rate recovery index (HRRI), a marker of autonomic nervous system function in patients with endemic fluorosis. Forty patients with endemic fluorosis (16 men/24 women) and 40 age-, sex-, and body mass index-matched healthy controls (16 men/24 women) with normal fluoride intake were enrolled in this study. HRRI was calculated by subtracting the heart rate values at the first, second, and third minutes of the recovery phase from the peak heart rate (HRRI 1, HRRI 2, HRRI 3). Urine fluoride levels of fluorosis patients were significantly (P?

Adali MK; Varol E; Aksoy F; Icli A; Ersoy IH; Ozaydin M; Erdogan D; Dogan A

2013-06-01

166

Impaired heart rate recovery in patients with endemic fluorosis.  

Science.gov (United States)

The objective of the present study was to determine the heart rate recovery index (HRRI), a marker of autonomic nervous system function in patients with endemic fluorosis. Forty patients with endemic fluorosis (16 men/24 women) and 40 age-, sex-, and body mass index-matched healthy controls (16 men/24 women) with normal fluoride intake were enrolled in this study. HRRI was calculated by subtracting the heart rate values at the first, second, and third minutes of the recovery phase from the peak heart rate (HRRI 1, HRRI 2, HRRI 3). Urine fluoride levels of fluorosis patients were significantly (P?fluorosis patients than in the controls. The incidence of abnormal HRRI 1 was significantly higher in fluorosis patients than in the controls (P?fluorosis. PMID:23417496

Adali, M Koray; Varol, Ercan; Aksoy, Fatih; Icli, Atilla; Ersoy, I Hakki; Ozaydin, Mehmet; Erdogan, Dogan; Dogan, Abdullah

2013-02-16

167

Cardiac peroxisome proliferator-activated receptor ? (PPAR?) as a new target for increased contractility without altering heart rate.  

UK PubMed Central (United Kingdom)

BACKGROUND AND AIMS: Agents having a positive inotropic effect on the heart are widely used for the treatment of heart failure. However, these agents have the side effect of altering heart rate. It has been established that peroxisome proliferator-activated receptor ? (PPAR?) is mediated in cardiac contraction, however the effect on heart rate is unknown. Thus, we used an agonist of PPAR?, GW0742, to investigate this issue in the present study. METHODS AND RESULTS: We used isolated hearts in Langendorff apparatus and hemodynamic analysis in catheterized rats to measure the actions of GW0742 extra-vivo and in vivo. In diabetic rats with heart failure, GW0742 at a dose sufficient to activate PPAR? reversed cardiac contraction without changes in heart rate. In normal rats, PPAR? enhanced cardiac contractility and hemodynamic dP/dtmax significantly more than dobutamine. Both actions were diminished by GSK0660 at a dose enough to block PPAR?. However, GW0742 at the same dose failed to modify heart rate, although it did produce a mild increase in blood pressure. Detection of intracellular calcium level and Western blotting analysis showed that the intracellular calcium concentration and troponin I phosphorylation were both enhanced by GW0742. CONCLUSION: Activation of PPAR? by GW0742 increases cardiac contractility but not heart rate. Thus, PPAR? may be a suitable target for the development of inotropic agents to treat heart failure without changing heart rate.

Chen ZC; Lee KS; Chen LJ; Wang LY; Niu HS; Cheng JT

2013-01-01

168

Cardiac Peroxisome Proliferator-Activated Receptor ? (PPAR?) as a New Target for Increased Contractility without Altering Heart Rate  

Science.gov (United States)

Background and Aims Agents having a positive inotropic effect on the heart are widely used for the treatment of heart failure. However, these agents have the side effect of altering heart rate. It has been established that peroxisome proliferator-activated receptor ? (PPAR?) is mediated in cardiac contraction, however the effect on heart rate is unknown. Thus, we used an agonist of PPAR?, GW0742, to investigate this issue in the present study. Methods and Results We used isolated hearts in Langendorff apparatus and hemodynamic analysis in catheterized rats to measure the actions of GW0742 extra-vivo and in vivo. In diabetic rats with heart failure, GW0742 at a dose sufficient to activate PPAR? reversed cardiac contraction without changes in heart rate. In normal rats, PPAR? enhanced cardiac contractility and hemodynamic dP/dtmax significantly more than dobutamine. Both actions were diminished by GSK0660 at a dose enough to block PPAR?. However, GW0742 at the same dose failed to modify heart rate, although it did produce a mild increase in blood pressure. Detection of intracellular calcium level and Western blotting analysis showed that the intracellular calcium concentration and troponin I phosphorylation were both enhanced by GW0742. Conclusion Activation of PPAR? by GW0742 increases cardiac contractility but not heart rate. Thus, PPAR? may be a suitable target for the development of inotropic agents to treat heart failure without changing heart rate.

Chen, Li-Jen; Wang, Lin-Yu; Niu, Ho-Shan; Cheng, Juei-Tang

2013-01-01

169

Development of a Fetal Heart Rate Detection Algorithm using Phonogram  

Energy Technology Data Exchange (ETDEWEB)

This study describes a fetal heart rate(FHR) estimation algorithm using phonogram. Using a phonogram amplifier, various fetal heart sounds are collected in a university hospital. The FHR estimation algorithm consists of a lowpass filter, decimation, envelop detection, pitch detection, and post-processing. The post-processing is the FHR decision procedure using all informations of fetal heart rates. Using the algorithm and other parameters of fetal heart sound, a fetal monitoring software was developed. This can display the original signals, the FFT spectra, FHR and its trajectory. Even though the fetal phonogram amplifier detects the fetal heart sounds well, the sound quality is not so good as the ultrasonography. In case of very week fetal heart sound, autocorrelation of it showed clear periodicity. But two main peaks in one period is an obstacle in pitch detection and peaks are not so vivid. The proposed FHR estimation algorithm showed very accurate and stable results. Since the developed software displays multiple parameters in real time and has convenient functions, it will be useful for the phonogram-style fetal monitoring device. (author). 14 refs., 17 figs.

Kim, D.J.; Kang, D.K. [Chongju University, Chongju (Korea)

2002-04-01

170

Heart rate variability and target organ damage in hypertensive patients  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background We evaluated the association between linear standard Heart Rate Variability (HRV) measures and vascular, renal and cardiac target organ damage (TOD). Methods A retrospective analysis was performed including 200 patients registered in the Regione Campania network (aged 62.4?±?12, male 64%). HRV analysis was performed by 24-h holter ECG. Renal damage was assessed by estimated glomerular filtration rate (eGFR), vascular damage by carotid intima-media thickness (IMT), and cardiac damage by left ventricular mass index. Results Significantly lower values of the ratio of low to high frequency power (LF/HF) were found in the patients with moderate or severe eGFR (p-value? Conclusions Depressed HRV appeared to be associated with vascular and renal TOD, suggesting the involvement of autonomic imbalance in the TOD. However, as the mechanisms by which abnormal autonomic balance may lead to TOD, and, particularly, to renal organ damage are not clearly known, further prospective studies with longitudinal design are needed to determine the association between HRV and the development of TOD.

Melillo Paolo; Izzo Raffaele; De Luca Nicola; Pecchia Leandro

2012-01-01

171

Development of heart and respiratory rate percentile curves for hospitalized children.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To develop and validate heart and respiratory rate percentile curves for hospitalized children and compare their vital sign distributions to textbook reference ranges and pediatric early warning score (EWS) parameters. METHODS: For this cross-sectional study, we used 6 months of nurse-documented heart and respiratory rates from the electronic records of 14,014 children on general medical and surgical wards at 2 tertiary-care children's hospitals. We developed percentile curves using generalized additive models for location, scale, and shape with 67% of the patients and validated the curves with the remaining 33%. We then determined the proportion of observations that deviated from textbook reference ranges and EWS parameters. RESULTS: We used 116,383 heart rate and 116,383 respiratory rate values to develop and validate the percentile curves. Up to 54% of heart rate observations and up to 40% of respiratory rate observations in our sample were outside textbook reference ranges. Up to 38% of heart rate observations and up to 30% of respiratory rate observations in our sample would have resulted in increased EWSs. CONCLUSIONS: A high proportion of vital signs among hospitalized children would be considered out of range according to existing reference ranges and pediatric EWSs. The percentiles we derived may serve as useful references for clinicians and could be used to inform the development of evidence-based vital sign parameters for physiologic monitor alarms, inpatient electronic health record vital sign alerts, medical emergency team calling criteria, and EWSs.

Bonafide CP; Brady PW; Keren R; Conway PH; Marsolo K; Daymont C

2013-04-01

172

The relationship between heart rate reserve and oxygen uptake reserve in heart failure patients on optimized and non-optimized beta-blocker therapy  

Directory of Open Access Journals (Sweden)

Full Text Available BACKGROUND: The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients either on non-optimized or off beta-blocker therapy is known to be unreliable. The aim of this study was to evaluate the relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients receiving optimized and non-optimized beta-blocker treatment during a treadmill cardiopulmonary exercise test. METHODS: A total of 27 sedentary heart failure patients (86% male, 50±12 years) on optimized beta-blocker therapy with a left ventricle ejection fraction of 33±8% and 35 sedentary non-optimized heart failure patients (75% male, 47±10 years) with a left ventricle ejection fraction of 30±10% underwent the treadmill cardiopulmonary exercise test (Naughton protocol). Resting and peak effort values of both the percentage of oxygen consumption reserve and percentage of heart rate reserve were, by definition, 0 and 100, respectively. RESULTS: The heart rate slope for the non-optimized group was derived from the points 0.949±0.088 (0 intercept) and 1.055±0.128 (1 intercept), p<0.0001. The heart rate slope for the optimized group was derived from the points 1.026±0.108 (0 intercept) and 1.012±0.108 (1 intercept), p=0.47. Regression linear plots for the heart rate slope for each patient in the non-optimized and optimized groups revealed a slope of 0.986 (almost perfect) for the optimized group, but the regression analysis for the non-optimized group was 0.030 (far from perfect, which occurs at 1). CONCLUSION: The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in patients on optimized beta-blocker therapy was reliable, but this relationship was unreliable in non-optimized heart failure patients.

Vitor Oliveira Carvalho; Guilherme Veiga Guimarães; Edimar Alcides Bocchi

2008-01-01

173

Heart rate variability as determinism with jump stochastic parameters.  

UK PubMed Central (United Kingdom)

We use measured heart rate information (RR intervals) to develop a one-dimensional nonlinear map that describes short term deterministic behavior in the data. Our study suggests that there is a stochastic parameter with persistence which causes the heart rate and rhythm system to wander about a bifurcation point. We propose a modified circle map with a jump process noise term as a model which can qualitatively capture such this behavior of low dimensional transient determinism with occasional (stochastically defined) jumps from one deterministic system to another within a one parameter family of deterministic systems.

Zheng J; Skufca JD; Bollt EM

2013-08-01

174

Pathophysiology of exercise heart rate recovery: a comprehensive analysis.  

UK PubMed Central (United Kingdom)

Expanded use of exercise heart rate recovery (HRR) has renewed interest in the pathophysiology of heart rate control. This study uses basic physiologic principles to construct a unique model capable of describing the full time course of sympathetic and parasympathetic activity during HRR. The model is tested in a new study of 22 diverse subjects undergoing both maximal and submaximal treadmill exercise. Based on this analysis, prolongation of HRR involves changes within the sinus node, changes in sympathetic function, in parasympathetic function, and in the central mechanisms regulating autonomic balance. The methods may provide unique insight into alterations in autonomic control in health and disease.

Pierpont GL; Adabag S; Yannopoulos D

2013-03-01

175

Heart rate distribution and predictors of resting heart rate after initiation of beta-blocker treatment in patients with coronary artery disease: REsults of Sympathetic Evaluation And Research of China (RESEARCH) study.  

UK PubMed Central (United Kingdom)

BACKGROUND: The importance of heart rate as secondary prevention strategies for patients with coronary artery disease (CAD) is emphasized by multiple guidelines. However, limited information is available on the heart rate distribution and the change patterns of resting heart rate when initiating beta-blocker therapy among Chinese patients with CAD. METHODS: The REsults of Sympathetic Evaluation And Research of China (RESEARCH) study is a multi-centre, prospective, observational study involving 147 centers in 23 cities across China. All eligible beta-blocker naive patients were prescribed with metroprolol succinate. Initial dosage and target heart rate were selected at the discretion of their physicians in charge according to their usual institutional practice. The heart rate distribution and the change patterns of resting heart rate after initiation of beta-blocker therapy were observed. RESULTS: The majority of patients (63.6%) were prescribed with 47.5 mg metroprolol succinate. At baseline, there were only 17.4% of patients whose heart rate was less than 70 beats per minute, and the proportion reached 42.5% and 79.1%, one month and two months after initiation of beta-blockers, respectively. Multivariate linear regression analysis showed that baseline heart rate (B = 0.900, SE = 0.006, t = 141.787, P < 0.0001) and the dosage (B = -0.007, SE = 0.002, t = -3.242, P = 0.001) were independent predictors of resting heart rate 2 months after beta-blocker therapy. CONCLUSIONS: Resting heart rate is not optimally controlled in a broadly representative cohort of Chinese outpatients with CAD even after initiation of ?-blocker therapy, and baseline heart rate and the dosage of beta-blocker are both independent predictors of resting heart rate after ?-blocker therapy.

Zhao YX; Li YP; Gao F; Ma HY; Wang ZJ; Han HY; Shen H; Zhou YJ

2013-09-01

176

The effect of orthostatic stress on multiscale entropy of heart rate and blood pressure.  

UK PubMed Central (United Kingdom)

Cardiovascular control acts over multiple time scales, which introduces a significant amount of complexity to heart rate and blood pressure time series. Multiscale entropy (MSE) analysis has been developed to quantify the complexity of a time series over multiple time scales. In previous studies, MSE analyses identified impaired cardiovascular control and increased cardiovascular risk in various pathological conditions. Despite the increasing acceptance of the MSE technique in clinical research, information underpinning the involvement of the autonomic nervous system in the MSE of heart rate and blood pressure is lacking. The objective of this study is to investigate the effect of orthostatic challenge on the MSE of heart rate and blood pressure variability (HRV, BPV) and the correlation between MSE (complexity measures) and traditional linear (time and frequency domain) measures. MSE analysis of HRV and BPV was performed in 28 healthy young subjects on 1000 consecutive heart beats in the supine and standing positions. Sample entropy values were assessed on scales of 1-10. We found that MSE of heart rate and blood pressure signals is sensitive to changes in autonomic balance caused by postural change from the supine to the standing position. The effect of orthostatic challenge on heart rate and blood pressure complexity depended on the time scale under investigation. Entropy values did not correlate with the mean values of heart rate and blood pressure and showed only weak correlations with linear HRV and BPV measures. In conclusion, the MSE analysis of heart rate and blood pressure provides a sensitive tool to detect changes in autonomic balance as induced by postural change.

Turianikova Z; Javorka K; Baumert M; Calkovska A; Javorka M

2011-09-01

177

The effect of orthostatic stress on multiscale entropy of heart rate and blood pressure.  

Science.gov (United States)

Cardiovascular control acts over multiple time scales, which introduces a significant amount of complexity to heart rate and blood pressure time series. Multiscale entropy (MSE) analysis has been developed to quantify the complexity of a time series over multiple time scales. In previous studies, MSE analyses identified impaired cardiovascular control and increased cardiovascular risk in various pathological conditions. Despite the increasing acceptance of the MSE technique in clinical research, information underpinning the involvement of the autonomic nervous system in the MSE of heart rate and blood pressure is lacking. The objective of this study is to investigate the effect of orthostatic challenge on the MSE of heart rate and blood pressure variability (HRV, BPV) and the correlation between MSE (complexity measures) and traditional linear (time and frequency domain) measures. MSE analysis of HRV and BPV was performed in 28 healthy young subjects on 1000 consecutive heart beats in the supine and standing positions. Sample entropy values were assessed on scales of 1-10. We found that MSE of heart rate and blood pressure signals is sensitive to changes in autonomic balance caused by postural change from the supine to the standing position. The effect of orthostatic challenge on heart rate and blood pressure complexity depended on the time scale under investigation. Entropy values did not correlate with the mean values of heart rate and blood pressure and showed only weak correlations with linear HRV and BPV measures. In conclusion, the MSE analysis of heart rate and blood pressure provides a sensitive tool to detect changes in autonomic balance as induced by postural change. PMID:21799239

Turianikova, Zuzana; Javorka, Kamil; Baumert, Mathias; Calkovska, Andrea; Javorka, Michal

2011-07-28

178

Effect of interscalene brachial plexus block on heart rate variability.  

UK PubMed Central (United Kingdom)

BACKGROUND: Interscalene brachial plexus block (ISB) may be followed by cardiovascular instability. Until date, there is no clear picture available about the underlying mechanisms of ISB. In this study, we aimed to determine the changes in heart rate variability (HRV) parameters after ISB and the differences between right- and left-sided ISBs. METHODS: We prospectively studied 24 patients operated for shoulder surgery in sitting position and divided them into two respective groups: R (right-sided block = 14 pts) and L (left-sided block = 10 pts). HRV data were taken before and 30 min after the block. Ropivacaine without ephedrine was used for the ISB through an insulated block needle connected to a nerve stimulator. Statistical analysis implemented chi-square, Student's and t-paired tests. Skewed distributions were analyzed after logarithmic transformation. RESULTS: All the studied patients had successful blocks. Horner's syndrome signs were observed in 33.3% of the patients (R = 5/14, L = 3/10; [P = 0.769]). There were no significant differences in pre-block HRV between the groups. The application of ISB had differential effect on HRV variables: R-blocks increased QRS and QTc durations and InPNN50, while a statistical decrease was seen in InLF. L-blocks did not show any significant changes. These changes indicate a reduced sympathetic and an increased parasympathetic influence on the heart's autonomic flow after R-block. CONCLUSIONS: Based on the obtained results we conclude that ISB, possibly through extension of block to the ipsilateral stellate ganglion, alters the autonomic outflow to the central circulatory system in a way depending on the block's side.

Simeoforidou M; Vretzakis G; Chantzi E; Bareka M; Tsiaka K; Iatrou C; Karachalios T

2013-05-01

179

Heart rate recovery in exercise test in diabetic patients with and without microalbuminuria.  

UK PubMed Central (United Kingdom)

BACKGROUND: Diabetes mellitus (DM) has a lot of complications such as macrovessel and microvessel disease. Another complication of DM is cardiac autonomic neuropathy (CAN), which have effect on automatic nervous system of heart. Failure in heart rate slowing after exercise is a presentation of this abnormality. METHODS: We selected diabetic patients and divided them to case and control group based on microalbuminuria. Case group comprised of diabetic patients with microalbuminuria and control group included those without microalbuminuria. Patients in both groups exercised on treadmill using Bruce protocol and heart rate was measured in first and second minutes in the recovery period. RESULTS: We selected 35 patients with microalbuminuria (case group) and 35 without microalbuminuria (control group) among diabetic patients. No statistically significant difference was seen in sex and age between case and control groups. Heart rate recovery in the first minute of recovery in the case and control groups did not show significant difference; but in the second minute of recovery, it was significantly higher in control group (97 ± 19.4 vs. 101.9 ± 12.4 beat per minute, P = 0.04). CONCLUSION: In this study we evaluated the heart rate recovery or deceleration in diabetic patients with albuminuria and without microalbuminuria in recovery phase after exercise test. We found out that heart rate recovery at the second minute in the case and control groups has statistically significant difference but at the first minute, it did not.

Pourmoghaddas A; Moghaddasian A; Garakyaraghi M; Nezarat N; Mehrabi A

2013-05-01

180

Modeling baroreflex regulation of heart rate during orthostatic stress  

DEFF Research Database (Denmark)

During orthostatic stress, arterial and cardiopulmonary baroreflexes play a key role in maintaining arterial pressure by regulating heart rate. This study, presents a mathematical model that can predict the dynamics of heart rate regulation in response to postural change from sitting to standing. The model uses blood pressure measured in the finger as an input to model heart rate dynamics in response to changes in baroreceptor nerve firing rate, sympathetic and parasympathetic responses, vestibulo-sympathetic reflex, and concentrations of norepinephrine and acetylcholine. We formulate an inverse least squares problem for parameter estimation and successfully demonstrate that our mathematical model can accurately predict heart rate dynamics observed in data obtained from healthy young, healthy elderly, and hypertensive elderly subjects. One of our key findings indicates that to successfully validate our model against clinical data it is necessary to include the vestibulo-sympathetic reflex. Furthermore our model reveals that the transfer between the nerve firing and blood pressure is non-linear and follows a hysteresis curve. In healthy young people, the hysteresis loop is wide, while in healthy and hypertensive elderly people the hysteresis loop shifts to higher blood pressure values and its area is diminished. Finally, for hypertensive elderly people the hysteresis loop is generally not closed indicating that during postural change from sitting to standing, the blood pressure resettles at a different steady state value.

Olufsen, Mette; Tran, Hien T.

2006-01-01

 
 
 
 
181

Remote measurements of heart and respiration rates for telemedicine.  

Science.gov (United States)

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

Zhao, Fang; Li, Meng; Qian, Yi; Tsien, Joe Z

2013-10-08

182

Remote Measurements of Heart and Respiration Rates for Telemedicine  

Science.gov (United States)

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.

Qian, Yi; Tsien, Joe Z.

2013-01-01

183

Doppler Radar for Heartbeat Rate and Heart Rate Variability Extraction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a Doppler radar system used to detect the heartbeat signal from a d?istance of one meter. The proposed system is based on using a vector network analyzer and two antennas. Measurements are performed at 16 GHz for different power levels between 0 and -25 dBm. Both heartbeat rate a...

Obeid, Dany; Sadek, Sawsan; Zaharia, Gheorghe; El Zein, Ghaïs

184

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

Science.gov (United States)

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 ivabradine adjuvant to beta-blockers may pose an opportunity to further modulate outcome. PMID:22760479

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

2012-07-04

185

Effect of exercise on heart-rate response to mental stress in teenagers.  

UK PubMed Central (United Kingdom)

PURPOSE: We sought to determine if an exercise programme of moderate aerobic intensity would decrease the heart-rate response to mental stress in teenagers with normal hearts. METHODS: Mental stress testing (50 arithmetic problems) was performed in student volunteers before and after a 5-week period of rigorous aerobic exercise training of 2.5 h for 5 days/week. RESULTS: In the baseline state, the mental stress test increased the heart rate by an average of 20 ± 12 bpm to its observed peak at 30 s of testing (p < 0.001). Exercise training had a significant effect on the maximum heart rate (106 ± 19 vs. 89 ± 13 bpm, p < 0.001) and on the maximum increase in heart rate with mental stress (20 ± 12 pre vs. 9 ± 15 bpm post training, p < 0.001). CONCLUSION: Mental stress results in a marked heart response consistent with a marked neurohormonal effect. This response is effectively blunted by a 5-week moderately intensive exercise programme. These results should encourage endorsement of a regular exercise programme as an important lifestyle modification for improving maladaptive responses to stress.

Costin A; Costin N; Cohen P; Eisenach C; Marchlinski F

2013-08-01

186

Heart Rate Variability and Drawing Impairment in Hypoxemic COPD  

Science.gov (United States)

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…

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

187

Heart rate variability in sleep-related migraine without aura.  

UK PubMed Central (United Kingdom)

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.

Vollono C; Gnoni V; Testani E; Dittoni S; Losurdo A; Colicchio S; Di Blasi C; Mazza S; Farina B; Della Marca G

2013-07-01

188

When heart goes "BOOM" to fast. Heart rate greater than 80 as mortality predictor in acute myocardial infarction  

Science.gov (United States)

Many prospective studies established association between high heart rate and increased cardiovascular morbidity and mortality, independently of other risk factors. Heart rate over 80 beats per minute more often leads to atherosclerotic plaque disruption, the main step in developing acute coronary syndrome. Purpose was to investigate the incidence of higher heart rate levels in patients with anterior wall acute myocardial infarction with ST-segment elevation and the influence of heart rate on mortality. Research included 140 patients with anterior wall acute myocardial infarction with ST-segment elevation treated in Coronary Unit, Clinical Center Kragujevac in the period from January 2001-June 2006. Heart rate was calculated as the mean value of baseline and heart rate in the first 30 minutes after admission. Other risk factors were also followed to determine their connection with elevated heart rate. Results showed that the majority of patients survived (over 70%). In a total number of patients, more than 75% had a heart rate levels greater than 80 beats per minute. There was a significant difference in heart rate on addmision between survivors and patients who died, with a greater levels in patients with fatal outcome. Both, univariate and multivariate regression analysis singled out heart rate greater than 80 beats per minute as independent mortality predictor in these patients. Heart rate greater than 80 beats per minute is a major, independent risk factor for morbidity and important predictor of mortality in patients with acute myocardial infarction.

Davidovic, Goran; Iric-Cupic, Violeta; Milanov, Srdjan; Dimitijevic, Aleksandra; Petrovic-Janicijevic, Mirjana

2013-01-01

189

Heart Rate Recovery after Cognitive Challenge is Preserved with Age  

Science.gov (United States)

Objectives To investigate the effect of age on heart rate recovery (HRR) from cognitive challenge. Background Aging is an independent risk factor for the development of cardiovascular disease. HRR from exercise is an established predictor of cardiac morbidity and mortality, and evidence suggests that HRR from cognitive challenge is predictive of cardiac morbidity as well. Aging is associated with delayed HRR from exercise stress, but little is known about the effect of aging on HRR from psychological stress. We tested the hypothesis that age would be related to delayed HRR from psychological stress. Methods HRR following exposure to cognitive challenge (mental arithmetic and Stroop) was investigated in a sample of 436 participants aged 35–84 in MIDUS II, a national study of health and well-being. HRR was measured as (1) the amount of change from the stress level; (2) time to recover; and (3) the area under the curve (AUC). The analyses were controlled for medical comorbidities and medications that influence HR, such as BMI, smoking, sex, menopausal status, and amount of physical activity/exercise. Results There was no effect for age on HRR as evaluated by all three recovery assessment methods. Conclusions Contrary to expectation and in contrast to findings concerning HRR from exercise, HRR from cognitive challenge was preserved with age. These findings require further inquiry into differential mechanism(s) underlying HRR from psychological vs. exercise stress, including any role for improved emotion regulation with greater age.

Shcheslavskaya, Olga V.; Burg, Matthew M.; McKinley, Paula S.; Schwartz, Joseph E.; Gerin, William; Ryff, Carol D.; Weinstein, Maxine; Seeman, Teresa E.; Sloan, Richard P.

2010-01-01

190

Seminar conclusions  

Energy Technology Data Exchange (ETDEWEB)

To compete in a market economy, all businesses require a strategy which, when implemented, will enable to sell their products at a profit. As part of any business strategy, it is necessary to consider how the business can minimise the production costs. In the case of the chemical industry, raw materials and energy represent a significant part of production costs. Environmental safety audits can help to determine how such savings in raw materials and energy can be accomplished. Such audits can identify how much energy and raw materials are required for each unit of product; how much energy and raw materials are lost in the process and through the creation of wastes; and what steps can be taken to further cleaner production process. It was further recognized that audits help identify potential risks of major accidents and allow companies to identify practical means to reduce these risks. In light of this, it is recommended that: industry in Ukraine should make a commitment to apply environmental auditing procedures to relevant facilities, as described higher. Public authorities of Ukraine should support cleaner production strategies by different ways ( given in the conclusions). The OECD, should facilitate the implementation of cleaner production strategies in Ukraine by six well defined points. Last point, the western and private sector has and should continue to play an important role in transferring business and environmental know how.

NONE

1995-12-31

191

Office and 24-hour heart rate and target organ damage in hypertensive patients  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background We investigated the association between heart rate and its variability with the parameters that assess vascular, renal and cardiac target organ damage. Methods A cross-sectional study was performed including a consecutive sample of 360 hypertensive patients without heart rate lowering drugs (aged 56 ± 11 years, 64.2% male). Heart rate (HR) and its standard deviation (HRV) in clinical and 24-hour ambulatory monitoring were evaluated. Renal damage was assessed by glomerular filtration rate and albumin/creatinine ratio; vascular damage by carotid intima-media thickness and ankle/brachial index; and cardiac damage by the Cornell voltage-duration product and left ventricular mass index. Results There was a positive correlation between ambulatory, but not clinical, heart rate and its standard deviation with glomerular filtration rate, and a negative correlation with carotid intima-media thickness, and night/day ratio of systolic and diastolic blood pressure. There was no correlation with albumin/creatinine ratio, ankle/brachial index, Cornell voltage-duration product or left ventricular mass index. In the multiple linear regression analysis, after adjusting for age, the association of glomerular filtration rate and intima-media thickness with ambulatory heart rate and its standard deviation was lost. According to the logistic regression analysis, the predictors of any target organ damage were age (OR = 1.034 and 1.033) and night/day systolic blood pressure ratio (OR = 1.425 and 1.512). Neither 24 HR nor 24 HRV reached statistical significance. Conclusions High ambulatory heart rate and its variability, but not clinical HR, are associated with decreased carotid intima-media thickness and a higher glomerular filtration rate, although this is lost after adjusting for age. Trial Registration ClinicalTrials.gov: NCT01325064

García-García Ángel; Gómez-Marcos Manuel A; Recio-Rodríguez José I; Patino-Alonso Maria C; Rodríguez-Sánchez Emiliano; Agudo-Conde Cristina; García-Ortiz Luis

2012-01-01

192

An evaluation of heart rate variability and its modifying factors in children with type 1 diabetes.  

UK PubMed Central (United Kingdom)

Objective: To evaluate heart rate variability by Holter monitoring in type 1 diabetic children compared with a healthy control group and determine the factors modifying heart rate variability. Methods: This was designed as a prospective study comparing 28 patients, diagnosed with type 1 diabetes and under follow-up, with 27 healthy control group subjects. Results: The patients were aged 9.9 ± 4.2 years in the diabetic group, including 13 (46.5%) girls and 15 (53.5%) boys. The healthy control group comprised 20 (74%) girls and seven boys (26%) with an average age of 8.6 ± 3.7 years. The search for factors modifying heart rate variability yielded the following correlations: for the time-dependent variables, negative between age and both average and maximal heart rate (r = -0.263 and -0.460, respectively), negative between haemoglobin A1c and percentage of differences between adjacent RR intervals >50 ms, positive between diabetes duration and square root of the mean of the sum of squares of differences between adjacent NN intervals. The average heart rate and percentage of differences between adjacent RR intervals >50 ms was significantly higher in the girls than the boys in all groups. With regard to the frequency-dependent factors affecting heart rate variability, correlations were found between haemoglobin A1c level and both total power and very low frequency (r = -0.751 and -0.644) and between very low frequency and diabetes duration. Conclusion: A reduction in heart rate variability parameters was observed in type 1 diabetes mellitus patients who had a long disease duration or were poorly controlled, as compared with healthy controls.

Ozgür S; Ceylan O; Senocak F; Orün UA; Do?an V; Y?lmaz O; Keskin M; Aycan Z; Okutucu S; Karademir S

2013-09-01

193

Exposure to wood smoke increases arterial stiffness and decreases heart rate variability in humans.  

UK PubMed Central (United Kingdom)

BACKGROUND: Emissions from biomass combustion are a major source of indoor and outdoor air pollution, and are estimated to cause millions of premature deaths worldwide annually. Whilst adverse respiratory health effects of biomass exposure are well established, less is known about its effects on the cardiovascular system. In this study we assessed the effect of exposure to wood smoke on heart rate, blood pressure, central arterial stiffness and heart rate variability in otherwise healthy persons. METHODS: Fourteen healthy non-smoking subjects participated in a randomized, double-blind crossover study. Subjects were exposed to dilute wood smoke (mean particle concentration of 314+/-38 mug/m3) or filtered air for three hours during intermittent exercise. Heart rate, blood pressure, central arterial stiffness and heart rate variability were measured at baseline and for one hour post-exposure. RESULTS: Central arterial stiffness, measured as augmentation index, augmentation pressure and pulse wave velocity, was higher after wood smoke exposure as compared to filtered air (p < 0.01 for all), and heart rate was increased (p < 0.01) although there was no effect on blood pressure. Heart rate variability (SDNN, RMSSD and pNN50; p = 0.003, p < 0.001 and p < 0.001 respectively) was decreased one hour following exposure to wood smoke compared to filtered air. CONCLUSIONS: Acute exposure to wood smoke as a model of exposure to biomass combustion is associated with an immediate increase in central arterial stiffness and a simultaneous reduction in heart rate variability. As biomass is used for cooking and heating by a large fraction of the global population and is currently advocated as a sustainable alternative energy source, further studies are required to establish its likely impact on cardiovascular disease.Trial registration: ClinicalTrials.gov, NCT01488500.

Unosson J; Blomberg A; Sandström T; Muala A; Boman C; Nyström R; Westerholm R; Mills NL; Newby DE; Langrish JP; Bosson JA

2013-06-01

194

Functionality of the baroreceptor nerves in heart rate regulation  

DEFF Research Database (Denmark)

Two models describing the afferent baroreceptor firing are analyzed, a basic model predicting firing using a single nonlinear differential equation, and an extended model, coupling K nonlinear responses. Both models respond to the the rate (derivative) and the rate history of the carotid sinus arterial pressure. As a result both the rate and the relative level of the carotid sinus arterial pressure is sensed. Simulations with these models show that responses to step changes in pressure follow from the rate sensitivity as observed in experimental studies. Adaptation and asymmetric responses are a consequence of the memory encapsulated by the models, and the nonlinearity gives rise to sigmoidal response curves. The nonlinear afferent baroreceptor models are coupled with an effector model, and the coupled model has been used to predict baroreceptor feedback regulation of heart rate during postural change from sitting to standing and during head-up tilt. The efferent model couples the afferent nerve paths to the sympathetic and parasympathetic outflow, and subsequently predicts the build up of an action potential at the sinus knot of the heart. In this paper, we analyze the nonlinear afferent model and show that the coupled model is able to predict heart rate regulation using blood pressure data as an input.

Ottesen, Johnny T.; Olufsen, Mette

2011-01-01

195

Original paper Heart rate variability in adult patients with congenital heart disease  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Heart rate variability (HRV) illustrates an autonomic nervous system influence on the sinus node. It is known that low HRV parameters indicate poor prognosis in patients with myocardial infarction, predict sudden cardiac death and death due to heart failure. Adult population with congenital heart disease (CongHD) is particularly exposed to these complications. The aim of this study was to evaluate HRV parameters in adult patients with CongHD and to analyse the impact of the specific type of CongHD and past cardiac surgery on HRV.Materials and methods: Data of 345 adult patients aged 18-67 with CongHD were analysed. From the 24-hour ECG monitoring time domain indexes of HRV were calculated: SDNN, SDANN-i, SDNN-I, r-MSSD, pNN50.Results: All analysed HRV parameters were not different in CongHD patients comparing to the control group, and gradual, physiologic decrease due to aging was also present. Age at operation had no effect on HRV values, except in patients after correction of coarctation of the aorta (SDNNi r=-0.312; p=0.005; rMSSD r=-0.354; p=0.001; pNN50 r=-0.41; p=0.0001) and ventricular septal defect (rMSSD r=-0.310; p=0.02; pNN50 r=-0.336; p=0.01), where a negative correlation was found. Conclusions: 1. Despite slight differences between subgroups of CongHD patients, HRV values in adult patients with CongHD are similar to those in the healthy population, and gradual, physiologic decrease due to aging is also present. 2. Age at operation does not influence the HRV profile in the general population of patients with CongHD. Age at operation influences HRV in patients with left ventricle overload. Similar relations are not observed in the group with impaired right ventricle hemodynamics.

Olga Trojnarska; Piotr Br?borowicz; Magdalena ?anocha; Maciej Lesiak; Wies?aw Bryl; Andrzej Cie?li?ski

2005-01-01

196

Heart rate detection from an electronic weighing scale.  

Science.gov (United States)

We propose a novel technique for beat-to-beat heart rate detection based on the ballistocardiographic (BCG) force signal from a subject standing on a common electronic weighing scale. The detection relies on sensing force variations related to the blood acceleration in the aorta, works even if wearing footwear and does not require any sensors attached to the body because it uses the load cells in the scale. We have devised an approach to estimate the sensitivity and frequency response of three commercial weighing scales to assess their capability to detect the BCG force signal. Static sensitivities ranged from 490 nV V(-1) N(-1) to 1670 nV V(-1) N(-1). The frequency response depended on the subject's mass but it was broad enough for heart rate estimation. We have designed an electronic pulse detection system based on off-the-shelf integrated circuits to sense heart-beat-related force variations of about 0.24 N. The signal-to-noise ratio of the main peaks of the force signal detected was higher than 30 dB. A Bland-Altman plot was used to compare the RR time intervals estimated from the ECG and BCG force signals for 17 volunteers. The error was +/-21 ms, which makes the proposed technique suitable for short-term monitoring of the heart rate. PMID:18641428

González-Landaeta, R; Casas, O; Pallàs-Areny, R

2008-07-18

197

Music structure determines heart rate variability of singers.  

UK PubMed Central (United Kingdom)

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.

Vickhoff B; Malmgren H; Aström R; Nyberg G; Ekström SR; Engwall M; Snygg J; Nilsson M; Jörnsten R

2013-01-01

198

Compression based entropy estimation of heart rate variability on multiple time scales.  

UK PubMed Central (United Kingdom)

Heart rate fluctuates beat by beat in a complex manner. The aim of this study was to develop a framework for entropy assessment of heart rate fluctuations on multiple time scales. We employed the Lempel-Ziv algorithm for lossless data compression to investigate the compressibility of RR interval time series on different time scales, using a coarse-graining procedure. We estimated the entropy of RR interval time series of 20 young and 20 old subjects and also investigated the compressibility of randomly shuffled surrogate RR time series. The original RR time series displayed significantly smaller compression entropy values than randomized RR interval data. The RR interval time series of older subjects showed significantly different entropy characteristics over multiple time scales than those of younger subjects. In conclusion, data compression may be useful approach for multiscale entropy assessment of heart rate variability.

Baumert M; Voss A; Javorka M

2013-07-01

199

Heart rate correlates of utilitarian moral decision-making in alcoholism.  

UK PubMed Central (United Kingdom)

BACKGROUND: Recent studies of moral reasoning in patients with alcohol use disorders have indicated a 'utilitarian' bias, whereby patients are more likely to endorse emotionally aversive actions in favor of aggregate welfare (e.g., to kill a person in order to save a group of people). The aim of the present study was to examine psychophysiological correlates of this tendency indexed by heart rate. METHODS: The sample was composed by 31 alcohol-dependent individuals and 34 healthy controls without alcohol use disorders. Electrocardiogram was recorded at rest and during execution of a validated moral judgment task, including non-moral scenarios, and moral dilemmas that were either high in emotional salience ("personal scenarios") or low in emotional salience ("impersonal scenarios"). RESULTS: Alcohol-dependent individuals showed a blunted response to moral dilemmas. Furthermore, healthy controls displayed decreased heart rate to the personal vs. impersonal or non-moral scenarios, while alcohol-dependent individuals failed to differentiate dilemmas in terms of heart rate both prior decision-making and its post appraisal. These deficits were not related to baseline differences in Heart Rate. CONCLUSION: Our findings indicate that alcohol-dependent individuals failed to engage emotional aversive reactions to personal moral violations in terms of heart rate response.

Carmona-Perera M; Reyes Del Paso GA; Pérez-García M; Verdejo-García A

2013-07-01

200

Attenuated heart rate response is associated with hypocretin deficiency in patients with narcolepsy.  

UK PubMed Central (United Kingdom)

STUDY OBJECTIVE: Several studies have suggested that hypocretin-1 may influence the cerebral control of the cardiovascular system. We analyzed whether hypocretin-1 deficiency in narcolepsy patients may result in a reduced heart rate response. DESIGN: We analyzed the heart rate response during various sleep stages from a 1-night polysomnography in patients with narcolepsy and healthy controls. The narcolepsy group was subdivided by the presence of +/- cataplexy and +/- hypocretin-1 deficiency. SETTING: Sleep laboratory studies conducted from 2001-2011. PARTICIPANTS: In total 67 narcolepsy patients and 22 control subjects were included in the study. Cataplexy was present in 46 patients and hypocretin-1 deficiency in 38 patients. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: All patients with narcolepsy had a significantly reduced heart rate response associated with arousals and leg movements (P < 0.05). Heart rate response associated with arousals was significantly lower in the hypocretin-1 deficiency and cataplexy groups compared with patients with normal hypocretin-1 levels (P < 0.04) and patients without cataplexy (P < 0.04). Only hypocretin-1 deficiency significantly predicted the heart rate response associated with arousals in both REM and non-REM in a multivariate linear regression. CONCLUSIONS: Our results show that autonomic dysfunction is part of the narcoleptic phenotype, and that hypocretin-1 deficiency is the primary predictor of this dysfunction. This finding suggests that the hypocretin system participates in the modulation of cardiovascular function at rest.

Sorensen GL; Knudsen S; Petersen ER; Kempfner J; Gammeltoft S; Sorensen HB; Jennum P

2013-01-01

 
 
 
 
201

Is elevated pre-ictal heart rate associated with secondary generalization in partial epilepsy?  

UK PubMed Central (United Kingdom)

BACKGROUND: People with epilepsy are at risk for sudden unexpected death. Cardiac arrhythmia is one possible mechanism. We have studied seizure-related changes in cardiac rhythm. METHODS: Video-EEG and ECG from 38 patients with epileptic seizures during long-term monitoring for investigation of partial epilepsy with ictal impairment of consciousness were obtained. Seizures were classified as either complex partial or secondarily generalized. Inter-ictal, pre-ictal, ictal and post-ictal heart rate was calculated for the first recorded seizure. RESULTS: Heart rate during the pre-ictal period was higher (p=0.016) in patients with secondarily generalized seizures (n=11) compared to patients with complex partial seizures (n=27). Heart rate was also elevated during and after generalized seizures (p<0.015). Inter-ictal heart rate was not different in patients with secondary generalization compared to patients with partial seizures. CONCLUSION: We report elevated heart rate prior to partial seizure onset in those attacks which become secondarily generalized compared to seizures which remain localized. The finding may be relevant for the understanding of sudden death in epilepsy.

Nilsen KB; Haram M; Tangedal S; Sand T; Brodtkorb E

2010-06-01

202

Prognostic significance of heart rate in hospitalized patients presenting with myocardial infarction  

Directory of Open Access Journals (Sweden)

Full Text Available AIM: To investigate the prognostic significance of resting heart rate in patients with acute coronary syndrome (ACS), independent of other known factors. METHODS: Patients 40 years of age or older who had been admitted with acute coronary syndrome (ACS) to one of the 94 hospitals participating in the Prevalence of Peripheral Arterial Disease in Patients with Acute Coronary Syndrome (PAMISCA) study were included. Patients were divided into two groups based on their resting heart rate (HR ? or < 70 bpm). Complications were recording during a follow-up period of 1 year. RESULTS: There were 1054 ACS patients analyzed (43.5% with ST segment elevation and 56.5% without elevation). Mean age was 66.6 ± 11.7 years, 70.6% were male and 29.4% of subjects were female. During follow-up, more patients in the HR ? 70 bpm group were hospitalized for heart failure and they also had a higher mortality rate. In the multivariate analysis, a heart rate of ? 70 bpm was independently related to overall mortality during the follow-up period (hazard ratio 2.5; 95% confidence interval, 1.26-4.97, P = 0.009). CONCLUSION: A resting heart rate ? 70 bpm in patients who survive an ACS is an indicator of a high risk of suffering cardiovascular events during follow-up.

Lorenzo Fácila; Pedro Morillas; Juan Quiles; Federico Soria; Alberto Cordero; Pilar Mazón; Manuel Anguita; Cándido Martín-Luengo; Jose Ramón Gonzalez-Juanatey; Vicente Bertomeu; on behalf of the “The Prevalence of Peripheral Arterial Disease in Patients with Acute Coronary Syndrome” (PAMISCA) Investigators

2012-01-01

203

Suboccipital decompression enhances heart rate variability indices of cardiac control in healthy subjects.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Osteopathic manipulative treatment (OMT) focused on the upper cervical spine is theorized to affect the function of the vagus nerve and thereby influence the parasympathetic branch of the autonomic nervous system. This study was designed to determine the acute effect of upper cervical spine manipulation on cardiac autonomic control as measured by heart rate variability. DESIGN: Nineteen healthy, young adult subjects underwent three different experimental interventions administered in random order: cervical OMT, sham manipulation, and time control. Six minutes of electrocardiographic data were collected before and after each intervention, and heart rate variability was assessed by both time-domain and frequency-domain measures. RESULTS: No differences in resting heart rate or any measure of heart rate variability were observed between the baseline periods prior to each intervention. The OMT protocol resulted in an increase in the standard deviation of the normal-to-normal intervals (0.12±0.082 seconds, p<0.01), an increase in the high frequency spectral power (p=0.03), and a decrease in the low/high frequency spectral ratio (p=0.01) relative to the sham and time control conditions. No significant differences between sham and time control were observed (p>0.11 for all variables). CONCLUSIONS: These data support the hypothesis that upper cervical spine manipulation can acutely affect measures of heart rate variability in healthy individuals.

Giles PD; Hensel KL; Pacchia CF; Smith ML

2013-02-01

204

Embryonic Heart Rate correlation with pregnancy outcome in women with first trimester bleeding  

Directory of Open Access Journals (Sweden)

Full Text Available Objective : To assess the correlation between fetal heart rate and the fate of pregnancy in women with first trimester bleeding. Methods : This prospective observational study included 281 consecutive women with first trimester bleeding and Singleton pregnancies. The embryonic heart rate measured at the time of first trans-vaginal scan as per protocol in our university hospital for the evaluation of pregnancy. The heart rate was classified as slow if it was fewer than 110 beats per minute. The primary outcome measure is the occurrence of spontaneous early pregnancy loss prior to 12 weeks. Other outcome measures included the occurrence of late pregnancy loss (prior to 24 weeks), gestational age at birth, and fetal weight at birth. Results : Embryonic heart rate at less than 110 bpm was associated with a high likelihood of pregnancy loss. The sensitivity, specificity, positive and negative predictive value, and accuracy were 43.1%, 86%, 40.7%, 87.2%, and 78.2%, respectively. The OR (95% CI) of first-trimester pregnancy. Conclusion: embryonic heart rate can be an independent predictor of the outcome of pregnancy in women with intrauterine pregnancy complaining of first trimester bleeding.

Naemat Mohamed H.ELDin Shiry

2011-01-01

205

Heart rate variability in ?-thalassaemia major with or without cardiac siderosis.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Iron cardiomyopathy remains the major cause of death in ?-thalassaemia major. Excessive iron loading could lead to cardiac dysfunction and arrhythmias. Reduced heart rate variability is associated with a higher risk of arrhythmia and sudden death after myocardial infarction and heart failure. Previous data have reported on reduced heart rate variability in patients with marked cardiac iron accumulation. In this study, we compared heart rate variability among ?-thalassaemia major (TM) patients with or without cardiac siderosis. METHODS: Out of 70 ?-thalassaemia major patients with preserved ejection fractions, 38 patients with cardiac T2* magnetic resonance imaging assessment were included in our study. Time domain heart rate variability parameters were analysed from 24-hour recorded electrocardiograms and were compared with the control group. RESULTS: The mean T2* magnetic resonance imaging value was 22.9 ± 13.3 (4.7-47.5). In 21 patients with ?-thalassaemia major, the T2* magnetic resonance imaging values were greater than 20 ms and these patients were considered to be in the early stage of the disease. When we compare these patients with control subjects, the standard deviation of all NN intervals was still significantly lower (133.0 ± 32.2 versus 162.8 ± 32.9, p = 0.001) in ?-thalassaemia major patients despite normal T2* magnetic resonance imaging values. On the contrary, the standard deviation of all NN intervals was not correlated with haemoglobin levels in these patients (p > 0.05). CONCLUSIONS: Heart rate variability parameters were reduced even in ?-thalassaemia major patients without evident cardiac siderosis, as specified by magnetic resonance imaging data. The results of this study show that reduction of heart rate variability may start before cardiac iron loading is demonstrated by T2* magnetic resonance imaging in ?-thalassaemia major.

Alp A; Ozdogan O; Guloglu CC; Turker M; Atabay B

2013-02-01

206

HEART RATE AND ACTIVITY PROFILE FOR YOUNG FEMALE SOCCER  

Directory of Open Access Journals (Sweden)

Full Text Available The physical and physiological demands of high-level male soccer have been studied extensively, while few studies have investigated the demands placed on females during match-play, however, there is no information available about the heart rate and activity profile of young female soccer players during match play. Therefore, the aim of this study was to examine cardiovascular (heart-rates HR) and physical demands of young female soccer players during a match. Players were observed during a friendly competitive match (7-a-side) over 2 x 25-min halves. Match activities were assessed with Global Position System technology (1Hz). Result showed that young female soccer players attain 88±4.4% and 86.3±4.8% of HRmax during the first and second half respectively (P=0.3), the average heart rate was 87%. During the first and second half, they covered 2072±197 m and 1905±144 m (P13 km/h) resulted lower than that previously reported for age-matched male soccer players and elite female soccer players. This seems to indicate that gender and competitive level differences in match physical performance seem to occur mainly in the absolute match work-rate domain.

Barbero-Álvarez, JC.; Gómez-López, M; Barbero-Álvarez, V; Granda, J.; Castagna, C

2008-01-01

207

Frequency dependent effect of selective biphasic left vagus nerve stimulation on heart rate and arterial pressure  

Directory of Open Access Journals (Sweden)

Full Text Available Activation of the parasympathetic pathway leads to negative chronotropic, dromotropic, and inotropic changes of heart function. The ability to selectively stimulate certain superficial compartments of peripheral nerves has been demonstrated previously. The aim of the present study was to find a clinically acceptable selective biphasic vagus nerve stimulation technique, which could allow gradual regulation of heart rate and systemic arterial pressure. In two patients, the left vagus nerve was stimulated with a combination of quasi-trapezoidal cathodic and rectangular anodic current pulses with different stimulation frequencies (10Hz, 20Hz, 30Hz) and increasing current. The heart rate and systemic arterial pressure decreased with increasing current at all different stimulation frequencies (p<0.05). The heart rate and arterial pressure response was more gradual with 10Hz compared to 20Hz/30Hz vagus nerve stimulation (p<0.05). In conclusion, selective vagus nerve stimulation, with a combination of quasi-trapezoidal cathodic and rectangular anodic current pulses at 10Hz, offers gradual heart rate and systolic arterial pressure control.

MATEJ PODBREGAR; IVAN RADAN; TOMISLAV MIRKOVIC; IVAN KNEŽEVI?; BORUT GERŠAK; JANEZ ROZMAN

2012-01-01

208

Association of Psychosocial Factors and Heart Rate Variability in Heart Failure Patients.  

UK PubMed Central (United Kingdom)

The purpose of this study was to examine the association of psychosocial factors (depression, social support, and health-related quality of life) with heart rate variability (HRV) in patients with heart failure. The sample comprised 91 outpatients from a medical center. Data were collected using the Beck Depression Inventory-II, Medical Outcomes Study (MOS) Social Support Survey, and Minnesota Living With Heart Failure Questionnaire. HRV was measured in terms of time-domain parameters from a 24-hr ambulatory Holter electrocardiogram. After adjusting for demographic and clinical variables, quality of life and social support were significantly associated with HRV. HRV (time-domain measures) was significantly higher in patients who perceived better quality of life and more social support. Our findings suggest that nurses could screen early for patients' risk of adverse psychosocial conditions and suggest online or other social supportive interventions to help at-risk patients minimize the negative associations with HRV.

Kao CW; Tseng LF; Lin WS; Cheng SM

2013-09-01

209

Clinical significance of sinusoidal fetal heart rate pattern.  

UK PubMed Central (United Kingdom)

Sinusoidal fetal heart rate pattern has been regarded as a sign of fetal jeopardy and 92 instances of this pattern were analysed. The morphologically different major and minor sinusoidal patterns were assessed with regard to their clinical significance as predictors of fetal compromise. There were 83 instances of minor sinusoidal pattern (amplitude of oscillation less than 25 beats/min) with only one antepartum fetal death. Major sinusoidal pattern (amplitude of oscillation greater than 25 beats/min) was diagnosed in nine patients and in six of them the fetus died before, during or after delivery. It is concluded that patients with minor sinusoidal heart rate patterns may be managed expectantly, whereas on the rare occasion when a major sinusoidal pattern is seen expeditious delivery is justified.

Katz M; Meizner I; Shani N; Insler V

1983-09-01

210

Methods for heart rate variability analysis during sleep.  

UK PubMed Central (United Kingdom)

In the last years we have witnessed the growing interest in the heart rate variability (HRV) signal analysis during sleep. The study of the autonomic regulation during sleep allowed developing methods for automatic detection and classification of some sleep characteristics, both in physiological and pathological conditions. The main problems which require to be faced are the presence of frequent non-stationarities in the signal and the need of dealing with long term analysis, in order to provide reliable indices able to describe the whole night of sleep. In the present paper we are presenting some of the methodologies we recently employed in the study of the heart rate variability during sleep, ranging from time-frequency analysis to long time correlation. Some results are also presented, related to different applications, dealing with both physiological and pathological conditions.

Bianchi AM; Mendez MO

2013-07-01

211

Predicting energy expenditures for activities of caribou from heart rates  

Directory of Open Access Journals (Sweden)

Full Text Available Highly significant (P<0.001) linear relationships between oxygen comsumption (VO2) and heart rate (HR) were found for six caribou (Rangifer tarandus grand) at several times during the year. The standard error of the estimate for predicting VO2 from HR was within 10% of the mean VO2 for 9 of 13 caribou/season combinations. Energy expenditures by caribou while feeding on grain at a trough, grazing, browsing and walking within a large enclosure were 12%, 17%), 18% and 46% higher than the cost of standing. HR's recorded during a given activity decreased sharply during September and October, and reached a minimum in January. An abrupt increase in HR's of female caribou occurred 3 weeks prior to parturition. Heart rate telemetry can be used to determine the relative energy expenditures of free-ranging caribou with reasonable accuracy.

Steve G. Fancy; Robert G. White

1986-01-01

212

Heart rate variability related to effort at work.  

Science.gov (United States)

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. PMID:21356531

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

2011-02-26

213

Heart rate variability related to effort at work.  

UK PubMed Central (United Kingdom)

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.

Uusitalo A; Mets T; Martinmäki K; Mauno S; Kinnunen U; Rusko H

2011-11-01

214

The effects of hypnosis on heart rate variability.  

UK PubMed Central (United Kingdom)

Uslu et al. (2012 ) suggested that hypnotic status can modulate cerebral blood flow. The authors investigated the effects of hypnosis on heart rate variability (HRV). In women, HRV decreased during hypnosis. Posthypnotic values were higher compared to prehypnotic and hypnotic values. Women had highest HRV parameters in the posthypnotic condition. It appears that hypnosis can produce cardiac and cognitive activations. Hypnotherapy may be useful in some cardiac clinical conditions characterized by an autonomic imbalance or some cardiac arrhythmias.

Yüksel R; Ozcan O; Dane S

2013-04-01

215

The effects of hypnosis on heart rate variability.  

Science.gov (United States)

Uslu et al. (2012 ) suggested that hypnotic status can modulate cerebral blood flow. The authors investigated the effects of hypnosis on heart rate variability (HRV). In women, HRV decreased during hypnosis. Posthypnotic values were higher compared to prehypnotic and hypnotic values. Women had highest HRV parameters in the posthypnotic condition. It appears that hypnosis can produce cardiac and cognitive activations. Hypnotherapy may be useful in some cardiac clinical conditions characterized by an autonomic imbalance or some cardiac arrhythmias. PMID:23427840

Yüksel, Ramazan; Ozcan, Osman; Dane, Senol

2013-04-01

216

Impaired post exercise heart rate recovery in anabolic steroid users.  

Science.gov (United States)

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. PMID:23606338

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

2013-04-19

217

Experimental heart rate regulation in cycle-ergometer exercises.  

UK PubMed Central (United Kingdom)

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.

Paradiso M; Pietrosanti S; Scalzi S; Tomei P; Verrelli CM

2013-01-01

218

Heart rate, sympathetic cardiovascular influences, and the metabolic syndrome.  

UK PubMed Central (United Kingdom)

Alterations in glucose and lipid metabolism frequently cluster with overweight, obesity as well as hypertension in the clinical condition known as metabolic syndrome. The "cardiometabolic clustering" is characterized by well-known alterations that increase cardiovascular risk profile such as insulin-resistance, endothelial dysfunction, arterial stiffening, cardiac hypertrophy, and sympathetic activation. The present article will review the evidence collected throughout by years that an increase in the different markers of adrenergic drive, such as plasma norepinephrine and muscle sympathetic nerve traffic, characterizes this condition. Frequently, the increase also involves heart rate, as documented by the results of different epidemiological studies, such as the Pressioni Arteriose Monitorate E Loro Associazioni, in which an increase in heart rate has been shown in patients with metabolic syndrome, in which this hemodynamic parameter has been assessed in the doctor's office, at home, or during the 24-hour period. Finally, current findings suggest that in metabolic syndrome heart rate displays a significant correlation with other indirect and direct adrenergic markers. Taken together, these findings reinforce the concept that drugs used in the metabolic syndrome should exert sympathoinhibitory effects.

Grassi G; Arenare F; Quarti-Trevano F; Seravalle G; Mancia G

2009-07-01

219

Multi-detector computed tomography to analyze in-stent-restenoses at different heart rates  

International Nuclear Information System (INIS)

Purpose: This study was performed to evaluate the visualization of coronary in-stent restenosis by multi-detector computed tomography (MDCT). Materials and Methods: A restenosis phantom with different stented stenoses was used. The phantom was placed into a dynamic heart phantom with heart rates from 40 to 120 bpm. MDCT was performed with two scan protocols: a standard and an ultra-high resolution scan protocol. Results: Using the ultra-high resolution protocol, artifacts occurred at 0.6 mm around the stent struts (p30% was feasible up to 120 bpm. Conclusion: Multi-detector computed tomography ultra-high resolution scans allowed the assessment of a wide range of degrees of in-stent restenoses. In this experimental setup, standard protocols allowed a discrimination of low, moderate and high-grade stenoses even at heart rates above 100 bpm.

2008-01-01

220

Delta entropy of heart rate variability along with deepening anesthesia.  

UK PubMed Central (United Kingdom)

BACKGROUND: Conventional time and frequency domain measures of heart rate variability (HRV) are strongly influenced by anesthetic drugs, and are therefore not able to detect subtle changes in HRV, even during light anesthesia. Approximate entropy of R-R intervals is an HRV measure that has a tendency to decrease during anesthesia, but it is severely compromised by low-frequency variations of the signal. However, the negative effect of the low-frequency variations can be eliminated by differentiating the R-R interval tachogram before analysis. We designed this study to investigate characteristics of a novel HRV measure, named ? entropy (dEn), during deepening anesthesia. METHODS: Eight healthy subjects were anesthetized with sevoflurane and 8 with propofol in a stepwise manner using 3 escalating concentrations (2%, 3%, and 4% end-tidal concentration and 7.4 ± 1.7, 12.3 ± 2.6, and 18.3 ± 5.0 ?g/mL plasma concentration, respectively) at 30-minute intervals. A third group of 8 subjects received a supramaximal IV dose of glycopyrrolate without anesthesia to examine the effect of cardiac vagal activity on dEn. We computed dEn at baseline, during each step of anesthesia and during the anticholinergic blockade. RESULTS: The dEn decreased along with deepening levels of sevoflurane and propofol anesthesia up to 33% (95% confidence interval [CI] 21%-44%) and 38% (95% CI 28%-48%), respectively. At each anesthesia level, dEn differed significantly (P < 0.05) from that measured at the preceding level, similarly in both the sevoflurane and propofol groups. Parasympathetic blockade by glycopyrrolate was found to decrease dEn by 17% (95% CI 6%-28%). CONCLUSIONS: The dEn is a novel HRV measure able to detect subtle sympathetic- and parasympathetic-mediated alterations in HRV both during deepening levels of sevoflurane and propofol anesthesia and during exceedingly deep anesthesia.

Mäenpää M; Laitio T; Kuusela T; Penttilä J; Kaisti K; Aalto S; Hinkka-Yli-Salomäki S; Scheinin H

2011-03-01

 
 
 
 
221

Fetal heart rate pattern and umbilical cord nucleated RBC count  

Directory of Open Access Journals (Sweden)

Full Text Available "nBackground: Previous studies have suggested the presence of a relationship between the increase of NRBC and the duration and intensity of asphyxia. The purpose of this study was to evaluate the relationship of fetal heart rate pattern and the number of NRBC's in umbilical cord blood sample at birth. "nMethods: We enrolled 322 pregnant women with healthy, term fetuses who referred to Mirza Kouchak Khan Hospital for pregnancy termination in 2005 in a case-control study. All patients underwent continuous FHR monitoring and based on their FHR pattern, they were divided into two groups with normal FHR pattern and at least one abnormality in FHR pattern (including absence of beat to beat variability; absence of proper acceleration; and early, late, variable and prolonged deceleration). Samples of umbilical cord blood were evaluated for NRBC count and pH immediately after birth. The variables were compared in these two groups. "nResults: The mean NRBC count was significantly higher in patients with any kind of deceleration (late, variable, early or prolonged) in comparison with controls (respectively 11.88±4.406, 8.32±4.64, 10.58±5.366, and 4.11±4.913 vs. 0.93±1.790 in controls). Furthermore the mean NRBC count was significantly higher in patients with absence of acceleration or beat to beat variability (10.73±5.07 and 13.73±3.58 vs. 1.47±2.50). There was a negative correlation between 5th minute Apgar score and umbilical cord blood sample with mean NRBC count of umbilical cord blood sample. "nConclusion: Any abnormality in FHR pattern is associated with a significant increase in mean NRBC count of umbilical cord blood sample. There is also a significant relationship between the 5th minute Apgar score and umbilical cord blood sample pH, and mean NRBC count in umbilical cord blood sample.

Niroumanesh Sh; Mohebi M

2009-01-01

222

APPARATUS AND METHOD FOR DETECTING FETUS HEART SOUND AND HEART RATE USING MULTI-CHANNEL DOPPLER  

UK PubMed Central (United Kingdom)

PURPOSE: An apparatus and a method for detecting fetus heart sound and heart rate using multi-channel doppler are provided to detect a sound source within a short period of time by using ultrasonic sensors of N number to track a position of a transmitting and receiving sensor module. CONSTITUTION: An apparatus for detecting fetus heart sound and heart rate using multi-channel doppler includes an ultrasonic probe array(90), a channel selector(70), a beam forming module(30), and a microcomputer controller(10). The ultrasonic probe array(90) is formed with a plurality of ultrasonic probes to detect a sound source. The channel selector(70) is used for providing an ultrasonic wave to the ultrasonic probe array and controlling the ultrasonic probe array by collecting ultrasonic signals. The beam forming module(30) is used for extracting noiseless signals by averaging the collected ultrasonic signals. The microcomputer controller(10) extracts a position of the sound source and a generation signal by controlling the channel selector and the ultrasonic probe array.

JANG DONG PYO; KIM IN YOUNG; KIM SUN ILL; LEE SANG MIN

223

Gender differences of heart rate variability in healthy volunteers  

International Nuclear Information System (INIS)

Objective: To identify the basic values of heart rate variability in Pakistani population and to verify our hypothesis that there are gender differences in cardiovascular autonomic modulation. Methods: The descriptive cross sectional study based on convenience probability sampling was conducted at Armed Forces Institute of Cardiology/National Institute of Heart Diseases (AFIC/NIHD) Pakistan. The duration of the study was from December 2009 to July 2010. It involved 24-hour holter monitoring of 45 healthy individuals using holter electrocardiography (ECG) recorder. Heart rate variability was analysed in time (SDNN, SDANN, SDNNi, rMSSD, pNN50) and frequency domains (power, VLF, LF, and HF). Results: The time domain indices; SDNN (male=140 +- 36 ms vs. females=122 +- 33 ms; p =0.09), SDANN (male=123 +- 34 ms vs. females=111+- 34 ms; P= 0.23), SDNNi (male=64 +-19 ms vs. females=52 +- 14 ms; P= 0.03), and pNN50 (male=14 +- 10 ms vs. females=12 +- 7 ms; P= 0.43) were decreased in female volunteers when compared with males. Comparison of frequency domain indices; Total power (male=4041 +- 3150 ms/sup 2/ vs. females=2750 +- 1439 ms/sup 2/; P= 0.07), VLF (male=291 2675 ms/sup 2/ vs. females=1843 +- 928 ms/sup 2/; P= 0.06), LF (male=788 +- 397 ms/sup 2/ vs. females=556 +- 346 ms/sup 2/; P= 0.04) and HF (male=318 +- 251 ms/sup 2/ vs. females=31 277 ms/sup 2/; P= 0.94) amongst males and females showed attenuated heart rate variability in females. Of all the observed values, SDNNi and LF were found significantly (p

2012-01-01

224

Heart rate responses and fluid balance of competitive cross-country hang gliding pilots.  

UK PubMed Central (United Kingdom)

PURPOSE: To evaluate the physiological challenges of competitive cross-country hang gliding. METHODS: Seventeen experienced male pilots (age=41+/-9 y; mean+/-SD) were fitted with a monitor that recorded heart rate and altitude at 0.5 Hz throughout a competitive flight. Fluid losses were evaluated by comparing pilot pre- and postflight mass. RESULTS: The pilots' displacement was 88.4+/-43.7 km in 145.5+/-49.4 min. Mean flight altitude was 1902+/-427 m (range=1363-2601 m) with a maximum altitude of 2925+/-682 m (1870-3831 m). The mean in-flight heart rate of the pilots was 112+/-11 bpm (64+/-6% predicted HRmax). For all except one subject, heart rate was highest while launching (165+/-12 bpm, 93+/-7% predicted HRmax), followed by landing (154+/-13 bpm, 87+/-7% predicted HRmax). No statistically significant relationship was observed between heart rate during the launch and reported measures of state anxiety. Heart rate was inversely related (P<.01) to altitude for all pilots except one. Fluid loss during the flight was 1.32+/-0.70 L, which approximated 0.55 L/h, while mean in-flight fluid consumption was 0.39+/-0.44 L. Six pilots consumed no fluid during the flight. CONCLUSIONS: Even among experienced pilots, high heart rates are more a function of state anxiety than physical work demand. Fluid losses during flight are surprisingly moderate but pilots may still benefit from attending to fluid balance.

Morton DP

2010-03-01

225

Correlation of radiation dose and heart rate in dual-source computed tomography coronary angiography  

International Nuclear Information System (INIS)

Background: Computed tomography coronary angiography (CTCA) has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but the relatively high radiation dose remains a major concern. Purpose: To evaluate the relationship between radiation exposure and heart rate (HR), in dual-source CTCA. Material and Methods: Data from 218 CTCA examinations, performed with a dual-source 64-slices scanner, were statistically evaluated. Effective radiation dose, expressed in mSv, was calculated as the product of the dose-length product (DLP) times a conversion coefficient for the chest (mSv = DLPx0.017). Heart rate range and mean heart rate, expressed in beats per minute (bpm) of each individual during CTCA, were also provided by the system. Statistical analysis of effective dose and heart rate data was performed by using Pearson correlation coefficient and two-sample t-test. Results: Mean HR and effective dose were found to have a borderline positive relationship. Individuals with a mean HR >65 bpm observed to receive a statistically significant higher effective dose as compared to those with a mean HR =65 bpm. Moreover, a strong correlation between effective dose and variability of HR of more than 20 bpm was observed. Conclusion: Dual-source CT scanners are considered to have the capability to provide diagnostic examinations even with high HR and arrhythmias. However, it is desirable to keep the mean heart rate below 65 bpm and heart rate fluctuation less than 20 bpm in order to reduce the radiation exposure

2011-01-01

226

[ECG monitoring in full-term infants. Analysis of the rhythm and variability of heart rate  

UK PubMed Central (United Kingdom)

BACKGROUND: Heart Rate (HR) and Heart Rate Variability (HRV) depend on the neural control to the heart. HRV can be measured from 24-hours function. Little information is available on cardiac rhythm and on autonomic nervous control to the heart at birth. The aims of the study weew: 1) to study the cardiac rhythm in healthy newborn babies; 2) to asses the normal values for HRV at birth. METHODS: We studied 20 full term healthy newborn babies. Newborns underwent 24-hours ECG-Holter monitoring. Analysis was performed by a 750 A Del Mar Avionics Analyzer. We determined: Heart Rate (HR), number of extrasystoles, Standard Deviation of all R-R intervals over 24 hours (SDNN) and mean hourly HRV (HRVM). Results about HRV were matched with those of 50 healthy adults. RESULTS: 1) Average HR in the newborn babies was 108 (range: 55-198); we found high prevalence of supraventricular extrasystoles. 2) We determined reference value for HRV. SDNN was 55 +/- 17 ms in newborns. SDNN of adults was 132 +/- 25 ms (44% higher than in newborns; p < 0.001). HRVM was 46 +/- 14 ms in newborns and 76 +/- 14 ms (p < 0.001). CONCLUSION: 1) Larger intervals of HR in newborn babies compared to literature data and an high prevalence of supraventricular arrhythmias in full term healthy newborn babies. 2) Reference values for HRV in newborn babies. The low values of HRV confirm the immaturity of autonomic cardiac control.

Pandolfi M; Falsini G; Lazzerini S; Giani I; Rosati C; Mantini G; Grazzini M

1993-11-01

227

Effect of meditation on scaling behavior and complexity of human heart rate variability  

CERN Multimedia

The heart beat data recorded from samples before and during meditation are analyzed using two different scaling analysis methods. These analyses revealed that mediation severely affects the long range correlation of heart beat of a normal heart. Moreover, it is found that meditation induces periodic behavior in the heart beat. The complexity of the heart rate variability is quantified using multiscale entropy analysis and recurrence analysis. The complexity of the heart beat during mediation is found to be more.

Sarkar, A

2006-01-01

228

Association between the Rating Perceived Exertion, Heart Rate and Blood Lactate in Successive Judo Fights (Randori).  

UK PubMed Central (United Kingdom)

PURPOSE: This study aims to investigate the association between the rating of perceived exertion (RPE), heart rate (HR) and the blood lactate concentration ([La]) in successive judo fight simulations (randori). METHODS: TEN ATHLETES PARTICIPATED IN THE STUDY (AGE: 25.6±2.1 years; stature: 1.75±0.07 m; body mass: 75.6±14.9kg; %BF: 11.5±7.8%; practice: 14.5±6.2 years) and completed 4 judo fight simulations (T1 to T4) with duration of 5 min separated by 5 min passive recovery periods. Before each randori, [La] and HR were collected, and after each randori, the same measures and the RPE (CR-10 scale) were collected. RESULTS: SIGNIFICANT CORRELATIONS WERE OBSERVED BETWEEN: (1) CR-10 and HR (T2: r =0.70; T3: r =0.64; both, P<0.05); (2) ?CR-10 and ?[La] (T1-T2: r = .71, P< 0.05; T2-T3: r =0.92, P<0.01; T3-T4: r =0.73, P<0.05). Moreover, significant differences were noted in the behavior of the HR between the 2(nd) (T2) and 3(rd) (T3) judo fight simulations (P<0.05). CONCLUSION: The use of CR-10 in the evaluation process, as well as in deciding the load of training in judo, should be done with caution.

Branco BH; Massuça LM; Andreato LV; Marinho BF; Miarka B; Monteiro L; Franchini E

2013-06-01

229

Association between the Rating Perceived Exertion, Heart Rate and Blood Lactate in Successive Judo Fights (Randori)  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: This study aims to investigate the association between the rating of perceived exertion (RPE), heart rate (HR) and the blood lactate concentration ([La]) in successive judo fight simulations (randori).Methods: Ten athletes participated in the study (age: 25.6±2.1 years; stature: 1.75±0.07 m; body mass: 75.6±14.9kg; %BF: 11.5±7.8%; practice: 14.5±6.2 years) and completed 4 judo fight simulations (T1 to T4) with duration of 5 min separated by 5 min passive recovery periods. Before each randori, [La] and HR were collected, and after each randori, the same measures and the RPE (CR-10 scale) were collected.Results: Significant correlations were observed between: (1) CR-10 and HR (T2: r =0.70; T3: r =0.64; both, P<0.05); (2) ?CR-10 and ?[La] (T1-T2: r = .71, P< 0.05; T2-T3: r =0.92, P<0.01; T3-T4: r =0.73, P<0.05). Moreover, significant differences were noted in the behavior of the HR between the 2nd (T2) and 3rd (T3) judo fight simulations (P<0.05).Conclusion: The use of CR-10 in the evaluation process, as well as in deciding the load of training in judo, should be done with caution

Braulio Henrique Magnani Branco; Luis Miguel Massuça; Leonardo Vidal Andreato; Bianca Miarka; Luis Monteiro; Bruno Ferreira Marinho; Emerson Fanchini

2013-01-01

230

Assessing the California Transfer Function: The Transfer Rate and Its Measurement. Conclusions of the Data Needs Task Force.  

Science.gov (United States)

In the fall of 1989, the Intersegmental Coordinating Council organized the Data Needs Task Force (DNTF) to determine the feasibility of establishing a transfer rate definition. Specifically, the DNTF was charged with defining the information needed to strengthen intersegmental transfer programs, establishing common definitions (including "transfer…

Intersegmental Coordinating Council, Sacramento, CA.

231

Effects of changes in vertical occlusal dimension on heart rate fluctuations in guinea pigs.  

UK PubMed Central (United Kingdom)

BACKGROUND: We have previously reported that the decrease of the vertical occlusal dimension (VOD) led to heart failure and abnormalities in creatine phosphokinase (CPK) in guinea pigs. In the present study, we investigated the autonomic activity and the origin of the abnormality in CPK under different occlusal conditions. MATERIALS AND METHODS: Guinea pigs were separated into the following five groups: untreated control, reduced VOD, slit, restored VOD and increased VOD groups and compared for their electrocardiogram and heart rate fluctuations for two weeks using Fluclet, computer software. RESULTS: The control group revealed no changes in heart rate fluctuations or posture. The reduced VOD group exhibited a two-phase wave of heart rate fluctuations, with the first peak 0-2 days after teeth grinding, and the second peak starting from 4 days after teeth grinding until sudden death (usually 12th day), accompanied by head drop. The slit and the restored VOD groups exhibited only the first peak. The increased VOD group, with approximately 3 mm-thick acrylic pellets bonded to the posterior teeth, showed no heart rate fluctuations. Body weight loss was most prominent in the reduced VOD group, and became much milder in the order of increased VOD, restored and slit groups. The reduced VOD group exhibited transient elevation of skeletal muscle type of CPK isozyme activity within two days after treatment. CONCLUSION: The present study suggests that the first peak of heart rate fluctuations is caused by pulpal stimulation, and the second peak by excessive contraction (excessive excitation of the motor output system and the autonomic nervous system) of the masticatory muscles. On the other hand, increased VOD did not influence either the motor or the autonomic nervous system.

Taga H; Azuma Y; Maehara K; Nomura S

2012-03-01

232

A COMPARATIVE STUDY OF HEART RATE VARIABILITY IN DIABETIC SUBJECTS AND NORMAL SUBJECTS  

Directory of Open Access Journals (Sweden)

Full Text Available Aim: The main objective of this study is to enlighten medical faculty and diabetic patients about neurological and cardiovascular complications in Diabetes and to compare heart rate variability in normal individuals and diabetic patients. Materials and method :This research study was case-control study using Niviqure data acquisition system to record 5-minutes E.C.G. in 400 individuals who consisted of the cases group comprised of 200 diabetic patients and controls group consisted of 200 healthy individuals.5-minutes E.C.G. data gathered was subjected to frequency domain analysis of Heart Rate Variability and from which various parameter depicting parasympathetic activity and sympathetic activity were analyzed. HbA1c levels were estimated by high performance liquid chromatography. Statistical analysis was done using MS office excel 2007 software. Results: In the present study it was observed that parameters of heart rate variability are reduced (power of High Frequency-H.F., power of Low Frequency-L.F., total power-T.P. and L.F. /H.F. ratio) and parameters of heart rate variability depicting parasympathetic modulation of heart (H.F.) are more reduced when compared to parameters of heart rate variability depicting sympathetic modulation (L.F.) in diabetics compared to normal individuals. It was also found that there is a negative correlation between HbA1c values of subjects and parameters of HRV. Conclusion: These results may be attributed to early parasympathetic damage due to axonal degeneration of longer vagal fibers .This axonal degeneration is mostly caused due to chronically elevated levels of blood glucose.

Mudassir Mirza; Lakshmi A.N.R.

2012-01-01

233

256-slice CT coronary angiography in atrial fibrillation: The impact of mean heart rate and heart rate variability on image quality  

International Nuclear Information System (INIS)

Objective: The aim of this study was to evaluate the image quality of 256-MDCT in atrial fibrillation and to compare the findings with those among patients in sinus rhythm. Materials: All reconstructed images were evaluated by two independent experienced readers blinded to patient information, heart rate, and ECG results to assess the diagnostic quality of images of the coronary artery segments using axial images, multi-planar reformations, maximum intensity projections, and volume rendering technique. Results: No statistical significance was detected in terms of the overall image quality between patients in sinus rhythm and with atrial fibrillation. Pearson's correlation analysis showed no significant association between image quality and mean heart rate no matter for patients in sinus rhythm or with atrial fibrillation. Similarly, there was no correlation between image quality and heart rate variability for either patients in sinus rhythm or with atrial fibrillation. Our results showed that the optimal reconstruction window depends on patient's HR, and the pattern for patients in atrial fibrillation is similar to that obtained from non-atrial fibrillation patients. Conclusion: This study shows the potential of using 256-MDCT coronary angiography in patients with atrial fibrillation. Our results suggest that when appropriate reconstruction timing window is applied, patients with atrial fibrillation do not have to be excluded from MDCT coronary angiographic examinations.

2011-08-21

234

Comparison of heart rate variability adjusted for age and heart rate in women with rheumatoid arthritis and women without rheumatic diseases  

Directory of Open Access Journals (Sweden)

Full Text Available Aim. To compare the 24-hour indicators of heart rate variability (HRV), adjusted for age and 24-hour average heart rate (HR24) in women with rheumatoid arthritis (RA) and womenof the control group.Material and methods. Women with RA (n=291) at the age of 20-60 were examined. Women without rheumatic diseases (n=125) were included into control group. The presenceof traditional cardiovascular risk factors, the results of 24-hour ECG monitoring were assessed in addition to clinical symptoms, RA activity and severity. Transformation ofthe initial HRV parameters in their logarithms, and the standardization of the logarithms of age and HR24, the calculation of the exponential of the standardized logarithm wereperformed to remove the effects of age and heart rate on HRV.Results. Time and frequency HRV indices, adjusted for age and HP24 (HRVa) in women with RA were lower than these in women of control group. HRVa decline was observed in14–24% of women with RA. The maximum HRVa decrease was observed among the parameters that reflect an activity of parasympathetic autonomic nervous system (RMSSDn,pNN50n, HFn).Conclusion. The young and middle age women with RA differ from the women of the control group in significant decrease in the time and spectral HRV indices adjusted forage and HR24.

D.S. Novikova; T.V. Popkova; A.N. Gerasimov; A.V. Volkov; E.L. Nasonov

2013-01-01

235

256-slice CT coronary angiography in atrial fibrillation: The impact of mean heart rate and heart rate variability on image quality  

Energy Technology Data Exchange (ETDEWEB)

Objective: The aim of this study was to evaluate the image quality of 256-MDCT in atrial fibrillation and to compare the findings with those among patients in sinus rhythm. Materials: All reconstructed images were evaluated by two independent experienced readers blinded to patient information, heart rate, and ECG results to assess the diagnostic quality of images of the coronary artery segments using axial images, multi-planar reformations, maximum intensity projections, and volume rendering technique. Results: No statistical significance was detected in terms of the overall image quality between patients in sinus rhythm and with atrial fibrillation. Pearson's correlation analysis showed no significant association between image quality and mean heart rate no matter for patients in sinus rhythm or with atrial fibrillation. Similarly, there was no correlation between image quality and heart rate variability for either patients in sinus rhythm or with atrial fibrillation. Our results showed that the optimal reconstruction window depends on patient's HR, and the pattern for patients in atrial fibrillation is similar to that obtained from non-atrial fibrillation patients. Conclusion: This study shows the potential of using 256-MDCT coronary angiography in patients with atrial fibrillation. Our results suggest that when appropriate reconstruction timing window is applied, patients with atrial fibrillation do not have to be excluded from MDCT coronary angiographic examinations.

Chen, Liang-Kuang [Department of Radiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); College of Medicine, Fu Jen Catholic University, Taipei, Taiwan (China); Hsu, Shih-Ming [Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan (China); Mok, Greta S.P. [Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Macau (China); Law, Wei-Yip; Lu, Kun-Mu [Department of Radiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); Yang, Ching-Ching, E-mail: g39220003@yahoo.com.tw [Department of Radiological Technology, Tzu Chi College of Technology, 880, Sec.2, Chien-kuo Rd. Hualien 970, Taiwan (China); Wu, Tung-Hsin, E-mail: tung@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, 155 Li-Nong St., Sec. 2, Taipei 112, Taiwan (China)

2011-08-21

236

[The influence of individually fitted controlled breathing frequency on the heart rate variability indexes].  

UK PubMed Central (United Kingdom)

We studied the changes in indexes of variability of heart rate and fractal neurodynamics under conditions of controlled breathing on fluctuation frequency of a spectrum of heart rate. It is shown that the controlled breathing, which frequency corresponds to a frequency of localization of the maximum peak of capacity ofa heart rate in low-frequency is a powerful mechanism of management of heart rate and change of a functional condition of an organism as a whole.

Chuian OM; Biriukova OO; Ravaieva MIu

2010-01-01

237

Limited Value of Cystatin-C over Estimated Glomerular Filtration Rate for Heart Failure Risk Stratification  

Science.gov (United States)

Background To compare the prognostic value of estimated glomerular filtration rate, cystatin-C, an alternative renal biomarker, and their combination, in an outpatient population with heart failure.Estimated glomerular filtration rate is routinely used to assess renal function in heart failure patients. We recently demonstrated that the Cockroft-Gault formula is the best among the most commonly used estimated glomerular filtration rate formulas for predicting heart failure prognosis. Methodology/Principal Findings A total of 879 consecutive patients (72% men, age 70.4 years [P25–75 60.5–77.2]) were studied. The etiology of heart failure was mainly ischemic heart disease (52.7%). The left ventricular ejection fraction was 34% (P25–75 26–43%). Most patients were New York Heart Association class II (65.8%) or III (25.9%). During a median follow-up of 3.46 years (P25–75 1.85–5.05), 312 deaths were recorded. In an adjusted model, estimated glomerular filtration rate and cystatin-C showed similar prognostic value according to the area under the curve (0.763 and 0.765, respectively). In Cox regression, the multivariable analysis hazard ratios were 0.99 (95% CI: 0.98–1, P?=?0.006) and 1.14 (95% CI: 1.02–1.28, P?=?0.02) for estimated glomerular filtration rate and cystatin-C, respectively. Reclassification, assessed by the integration discrimination improvement and the net reclassification improvement indices, was poorer with cystatin-C (?0.5 [?1.0;?0.1], P?=?0.024 and ?4.9 [?8.8;?1.0], P?=?0.013, respectively). The value of cystatin-C over estimated glomerular filtration rate for risk-stratification only emerged in patients with moderate renal dysfunction (eGFR 30–60 ml/min/1.73 m2, chi-square 12.9, P<0.001). Conclusions/Significance Taken together, the results indicate that estimated glomerular filtration rate and cystatin-C have similar long-term predictive values in a real-life ambulatory heart failure population. Cystatin-C seems to offer improved prognostication in heart failure patients with moderate renal dysfunction.

Zamora, Elisabet; Lupon, Josep; de Antonio, Marta; Vila, Joan; Galan, Amparo; Gastelurrutia, Paloma; Urrutia, Agustin; Bayes-Genis, Antoni

2012-01-01

238

Heart rate: A global target for cardiovascular disease and therapy along the cardiovascular disease continuum.  

Science.gov (United States)

Heart rate is a predictor of cardiovascular and all-cause mortality in the general population and in patients with cardiovascular disease. Increased resting heart rate multiplies risk and interferes at all stages of the cardiovascular disease continuum initiating from endothelial dysfunction and continuing via atherosclerotic lesion formation and plaque rupture to end-stage cardiovascular disease. As a therapeutic target, heart rate is accessible via numerous pharmacological interventions. The concept of selective heart rate reduction by the I(f) current inhibitor ivabradine provides an option to intervene effectively along the chain of events and to define the specific and prognostic role of heart rate for patients with coronary artery disease and heart failure. Future interventional studies will further clarify the significance of heart rate and targeted heart rate reduction for primary and secondary prevention in cardiovascular and cerebrovascular events. PMID:23806547

Custodis, Florian; Reil, Jan-Christian; Laufs, Ulrich; Böhm, Michael

2013-06-24

239

Identification of heart rate-associated loci and their effects on cardiac conduction and rhythm disorders.  

Science.gov (United States)

Elevated resting heart rate is associated with greater risk of cardiovascular disease and mortality. In a 2-stage meta-analysis of genome-wide association studies in up to 181,171 individuals, we identified 14 new loci associated with heart rate and confirmed associations with all 7 previously established loci. Experimental downregulation of gene expression in Drosophila melanogaster and Danio rerio identified 20 genes at 11 loci that are relevant for heart rate regulation and highlight a role for genes involved in signal transmission, embryonic cardiac development and the pathophysiology of dilated cardiomyopathy, congenital heart failure and/or sudden cardiac death. In addition, genetic susceptibility to increased heart rate is associated with altered cardiac conduction and reduced risk of sick sinus syndrome, and both heart rate-increasing and heart rate-decreasing variants associate with risk of atrial fibrillation. Our findings provide fresh insights into the mechanisms regulating heart rate and identify new therapeutic targets. PMID:23583979

den Hoed, Marcel; Eijgelsheim, Mark; Esko, Tõnu; Brundel, Bianca J J M; Peal, David S; Evans, David M; Nolte, Ilja M; Segrè, Ayellet V; Holm, Hilma; Handsaker, Robert E; Westra, Harm-Jan; Johnson, Toby; Isaacs, Aaron; Yang, Jian; Lundby, Alicia; Zhao, Jing Hua; Kim, Young Jin; Go, Min Jin; Almgren, Peter; Bochud, Murielle; Boucher, Gabrielle; Cornelis, Marilyn C; Gudbjartsson, Daniel; Hadley, David; van der Harst, Pim; Hayward, Caroline; den Heijer, Martin; Igl, Wilmar; Jackson, Anne U; Kutalik, Zoltán; Luan, Jian'an; Kemp, John P; Kristiansson, Kati; Ladenvall, Claes; Lorentzon, Mattias; Montasser, May E; Njajou, Omer T; O'Reilly, Paul F; Padmanabhan, Sandosh; St Pourcain, Beate; Rankinen, Tuomo; Salo, Perttu; Tanaka, Toshiko; Timpson, Nicholas J; Vitart, Veronique; Waite, Lindsay; Wheeler, William; Zhang, Weihua; Draisma, Harmen H M; Feitosa, Mary F; Kerr, Kathleen F; Lind, Penelope A; Mihailov, Evelin; Onland-Moret, N Charlotte; Song, Ci; Weedon, Michael N; Xie, Weijia; Yengo, Loic; Absher, Devin; Albert, Christine M; Alonso, Alvaro; Arking, Dan E; de Bakker, Paul I W; Balkau, Beverley; Barlassina, Cristina; Benaglio, Paola; Bis, Joshua C; Bouatia-Naji, Nabila; Brage, Søren; Chanock, Stephen J; Chines, Peter S; Chung, Mina; Darbar, Dawood; Dina, Christian; Dörr, Marcus; Elliott, Paul; Felix, Stephan B; Fischer, Krista; Fuchsberger, Christian; de Geus, Eco J C; Goyette, Philippe; Gudnason, Vilmundur; Harris, Tamara B; Hartikainen, Anna-Liisa; Havulinna, Aki S; Heckbert, Susan R; Hicks, Andrew A; Hofman, Albert; Holewijn, Suzanne; Hoogstra-Berends, Femke; Hottenga, Jouke-Jan; Jensen, Majken K; Johansson, Asa; Junttila, Juhani; Kääb, Stefan; Kanon, Bart; Ketkar, Shamika; Khaw, Kay-Tee; Knowles, Joshua W; Kooner, Angrad S; Kors, Jan A; Kumari, Meena; Milani, Lili; Laiho, Päivi; Lakatta, Edward G; Langenberg, Claudia; Leusink, Maarten; Liu, Yongmei; Luben, Robert N; Lunetta, Kathryn L; Lynch, Stacey N; Markus, Marcello R P; Marques-Vidal, Pedro; Mateo Leach, Irene; McArdle, Wendy L; McCarroll, Steven A; Medland, Sarah E; Miller, Kathryn A; Montgomery, Grant W; Morrison, Alanna C; Müller-Nurasyid, Martina; Navarro, Pau; Nelis, Mari; O'Connell, Jeffrey R; O'Donnell, Christopher J; Ong, Ken K; Newman, Anne B; Peters, Annette; Polasek, Ozren; Pouta, Anneli; Pramstaller, Peter P; Psaty, Bruce M; Rao, Dabeeru C; Ring, Susan M; Rossin, Elizabeth J; Rudan, Diana; Sanna, Serena; Scott, Robert A; Sehmi, Jaban S; Sharp, Stephen; Shin, Jordan T; Singleton, Andrew B; Smith, Albert V; Soranzo, Nicole; Spector, Tim D; Stewart, Chip; Stringham, Heather M; Tarasov, Kirill V; Uitterlinden, André G; Vandenput, Liesbeth; Hwang, Shih-Jen; Whitfield, John B; Wijmenga, Cisca; Wild, Sarah H; Willemsen, Gonneke; Wilson, James F; Witteman, Jacqueline C M; Wong, Andrew; Wong, Quenna; Jamshidi, Yalda; Zitting, Paavo; Boer, Jolanda M A; Boomsma, Dorret I; Borecki, Ingrid B; van Duijn, Cornelia M; Ekelund, Ulf; Forouhi, Nita G; Froguel, Philippe; Hingorani, Aroon; Ingelsson, Erik; Kivimaki, Mika; Kronmal, Richard A; Kuh, Diana; Lind, Lars; Martin, Nicholas G; Oostra, Ben A; Pedersen, Nancy L; Quertermous, Thomas; Rotter, Jerome I; van der Schouw, Yvonne T; Verschuren, W M Monique; Walker, Mark; Albanes, Demetrius; Arnar, David O; Assimes, Themistocles L; Bandinelli, Stefania; Boehnke, Michael; de Boer, Rudolf A; Bouchard, Claude; Caulfield, W L Mark; Chambers, John C; Curhan, Gary; Cusi, Daniele; Eriksson, Johan; Ferrucci, Luigi; van Gilst, Wiek H; Glorioso, Nicola; de Graaf, Jacqueline; Groop, Leif; Gyllensten, Ulf; Hsueh, Wen-Chi; Hu, Frank B; Huikuri, Heikki V; Hunter, David J; Iribarren, Carlos; Isomaa, Bo; Jarvelin, Marjo-Riitta; Jula, Antti; Kähönen, Mika; Kiemeney, Lambertus A; van der Klauw, Melanie M; Kooner, Jaspal S; Kraft, Peter; Iacoviello, Licia; Lehtimäki, Terho; Lokki, Marja-Liisa L; Mitchell, Braxton D; Navis, Gerjan; Nieminen, Markku S; Ohlsson, Claes; Poulter, Neil R; Qi, Lu; Raitakari, Olli T; Rimm, Eric B; Rioux, John D; Rizzi, Federica; Rudan, Igor; Salomaa, Veikko; Sever, Peter S; Shields, Denis C; Shuldiner, Alan R; Sinisalo, Juha; Stanton, Alice V; Stolk, Ronald P; Strachan, David P; Tardif, Jean-Claude; Thorsteinsdottir, Unnur; Tuomilehto, Jaako; van Veldhuisen, Dirk J; Virtamo, Jarmo; Viikari, Jorma; Vollenweider, Peter; Waeber, Gérard; Widen, Elisabeth; Cho, Yoon Shin; Olsen, Jesper V; Visscher, Peter M; Willer, Cristen; Franke, Lude; Erdmann, Jeanette; Thompson, John R; Pfeufer, Arne; Sotoodehnia, Nona; Newton-Cheh, Christopher; Ellinor, Patrick T; Stricker, Bruno H Ch; Metspalu, Andres; Perola, Markus

2013-04-14

240

Identification of heart rate-associated loci and their effects on cardiac conduction and rhythm disorders.  

UK PubMed Central (United Kingdom)

Elevated resting heart rate is associated with greater risk of cardiovascular disease and mortality. In a 2-stage meta-analysis of genome-wide association studies in up to 181,171 individuals, we identified 14 new loci associated with heart rate and confirmed associations with all 7 previously established loci. Experimental downregulation of gene expression in Drosophila melanogaster and Danio rerio identified 20 genes at 11 loci that are relevant for heart rate regulation and highlight a role for genes involved in signal transmission, embryonic cardiac development and the pathophysiology of dilated cardiomyopathy, congenital heart failure and/or sudden cardiac death. In addition, genetic susceptibility to increased heart rate is associated with altered cardiac conduction and reduced risk of sick sinus syndrome, and both heart rate-increasing and heart rate-decreasing variants associate with risk of atrial fibrillation. Our findings provide fresh insights into the mechanisms regulating heart rate and identify new therapeutic targets.

den Hoed M; Eijgelsheim M; Esko T; Brundel BJ; Peal DS; Evans DM; Nolte IM; Segrè AV; Holm H; Handsaker RE; Westra HJ; Johnson T; Isaacs A; Yang J; Lundby A; Zhao JH; Kim YJ; Go MJ; Almgren P; Bochud M; Boucher G; Cornelis MC; Gudbjartsson D; Hadley D; van der Harst P; Hayward C; den Heijer M; Igl W; Jackson AU; Kutalik Z; Luan J; Kemp JP; Kristiansson K; Ladenvall C; Lorentzon M; Montasser ME; Njajou OT; O'Reilly PF; Padmanabhan S; St Pourcain B; Rankinen T; Salo P; Tanaka T; Timpson NJ; Vitart V; Waite L; Wheeler W; Zhang W; Draisma HH; Feitosa MF; Kerr KF; Lind PA; Mihailov E; Onland-Moret NC; Song C; Weedon MN; Xie W; Yengo L; Absher D; Albert CM; Alonso A; Arking DE; de Bakker PI; Balkau B; Barlassina C; Benaglio P; Bis JC; Bouatia-Naji N; Brage S; Chanock SJ; Chines PS; Chung M; Darbar D; Dina C; Dörr M; Elliott P; Felix SB; Fischer K; Fuchsberger C; de Geus EJ; Goyette P; Gudnason V; Harris TB; Hartikainen AL; Havulinna AS; Heckbert SR; Hicks AA; Hofman A; Holewijn S; Hoogstra-Berends F; Hottenga JJ; Jensen MK; Johansson A; Junttila J; Kääb S; Kanon B; Ketkar S; Khaw KT; Knowles JW; Kooner AS; Kors JA; Kumari M; Milani L; Laiho P; Lakatta EG; Langenberg C; Leusink M; Liu Y; Luben RN; Lunetta KL; Lynch SN; Markus MR; Marques-Vidal P; Mateo Leach I; McArdle WL; McCarroll SA; Medland SE; Miller KA; Montgomery GW; Morrison AC; Müller-Nurasyid M; Navarro P; Nelis M; O'Connell JR; O'Donnell CJ; Ong KK; Newman AB; Peters A; Polasek O; Pouta A; Pramstaller PP; Psaty BM; Rao DC; Ring SM; Rossin EJ; Rudan D; Sanna S; Scott RA; Sehmi JS; Sharp S; Shin JT; Singleton AB; Smith AV; Soranzo N; Spector TD; Stewart C; Stringham HM; Tarasov KV; Uitterlinden AG; Vandenput L; Hwang SJ; Whitfield JB; Wijmenga C; Wild SH; Willemsen G; Wilson JF; Witteman JC; Wong A; Wong Q; Jamshidi Y; Zitting P; Boer JM; Boomsma DI; Borecki IB; van Duijn CM; Ekelund U; Forouhi NG; Froguel P; Hingorani A; Ingelsson E; Kivimaki M; Kronmal RA; Kuh D; Lind L; Martin NG; Oostra BA; Pedersen NL; Quertermous T; Rotter JI; van der Schouw YT; Verschuren WM; Walker M; Albanes D; Arnar DO; Assimes TL; Bandinelli S; Boehnke M; de Boer RA; Bouchard C; Caulfield WL; Chambers JC; Curhan G; Cusi D; Eriksson J; Ferrucci L; van Gilst WH; Glorioso N; de Graaf J; Groop L; Gyllensten U; Hsueh WC; Hu FB; Huikuri HV; Hunter DJ; Iribarren C; Isomaa B; Jarvelin MR; Jula A; Kähönen M; Kiemeney LA; van der Klauw MM; Kooner JS; Kraft P; Iacoviello L; Lehtimäki T; Lokki ML; Mitchell BD; Navis G; Nieminen MS; Ohlsson C; Poulter NR; Qi L; Raitakari OT; Rimm EB; Rioux JD; Rizzi F; Rudan I; Salomaa V; Sever PS; Shields DC; Shuldiner AR; Sinisalo J; Stanton AV; Stolk RP; Strachan DP; Tardif JC; Thorsteinsdottir U; Tuomilehto J; van Veldhuisen DJ; Virtamo J; Viikari J; Vollenweider P; Waeber G; Widen E; Cho YS; Olsen JV; Visscher PM; Willer C; Franke L; Erdmann J; Thompson JR; Pfeufer A; Sotoodehnia N; Newton-Cheh C; Ellinor PT; Stricker BH; Metspalu A; Perola M; Beckmann JS; Smith GD; Stefansson K; Wareham NJ; Munroe PB; Sibon OC; Milan DJ; Snieder H; Samani NJ; Loos RJ

2013-06-01

 
 
 
 
241

Omega-3 Polyunsaturated Fatty Acids and Heart Rate Variability  

DEFF Research Database (Denmark)

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 afteromega-3 PUFA supplementation. However, the results are not consistent and further research is needed.

Christensen, Jeppe Hagstrup

2011-01-01

242

Aging Affects the Response of Heart Rate Variability Autonomic Indices to Atropine and Isoproteronol  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Normalized ratios of portions of the power frequency spectrum of heart rate (HR) are commonly used to gain insight into cardiac “sympathovagal balance.” Whether aging, which alters both sympathtetic and parasympathetic activities, infl uences these measures has not been well characterized.Objectives: We examined the ability of normalized ratios of the power frequency spectrum of heart rate to describe autonomic activity at the sinus node in older and younger adults during conditions of sympathetic predominance.Methods: 20 older (mean age 70.0 ± 1.5 years) and 24 younger (mean age 25.4 ± 0.9 years) normal adults were screened by history, physical examination, blood work (CBC, electrolytes, creatinine, liver function tests), ECG, exercise tolerance test, echocardiogram and myocardial perfusion scan (if 65 years old). A 2-channel Holter was used to monitor heart rate. Total (TP), low frequency (LF) and high frequency power (HF) were obtained by Fast Fourier Transform. Intravenous atropine (2 boluses of 0.01 mg/kg) was followed by isoproterenol infusions of 7 and 21 ng/kg/min to tilt the “sympathovagal balance” to the sympathetic nervous system side.Results: Normalized HF power gave expected results in response to atropine only in younger subjects. Changes in normalized LF power had a much stronger correlation with changes in heart rate in older as opposed to younger subjects.Conclusions: The response of normalized power ratios to atropine and isoproterenol varies between different age groups.

Kenneth M. Madden; Wayne C. Levy; John R. Stratton

2008-01-01

243

Time Domain Measures of Heart Rate Variability to Assess Autonomic Dysfunction In Irritable Bowel Syndrome  

Directory of Open Access Journals (Sweden)

Full Text Available AbstractBackground: Autonomic nerve function impairment is related to development of Irritable Bowel Syndrome (IBS). Time domain measures of Heart rate variability (HRV) is a useful tool to measure autonomic nerve function activity.Objective: To assess autonomic nerve function activity by time domain measures of heart rate variability in patients with Irritable Bowel Syndrome.Methods: This cross sectional study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka in 2011. Ninety patients aged 20-50 years of both sex with Irritable bowel syndrome were included in the study group. They were collected from the OPD of Gastroenterology in BSMMU. Age and sex matched 30 apparently healthy subjects served as control. For assessing HRV by time domain method, Mean heart rate Mean R-R interval, Max/Min R-R interval, SDNN, RMSSD, PNN50%, NN50% were recorded by a digital Polyrite. ANOVA, independent sample t-test and Pearson’s correlation coefficient tests were performed as applicable.Results: Mean heart rate were significantly higher and Mean R-R interval, Max/Min R-R interval, SDNN, RMSSD, PNN50%, NN50% were significantly lower in IBS groups compared to those of control. Correlation analysis showed negative correlations of SDNN, RMSSD, PNN50%, NN50% with duration of disease.Conclusion: This study concludes that parasympathetic activity was reduced in patients of IBS. In addition, decreased vagal modulation is inversely related to the duration IBS.

Mohammad Nayem, Noorzahan Begum, Sultana Ferdousi

2012-01-01

244

Heart rate variability and baroreceptor responsiveness to evaluate autonomic cardiovascular adaptations to exercise  

Directory of Open Access Journals (Sweden)

Full Text Available Exercise physiologists routinely evaluate adaptations to exercise such as aerobic capacity, muscular strength and flexibility, and body composition, but often overlook the effects of exercise training on autonomic regulation of cardiovascular function. A preponderance of cross-sectional studies report significant resting sinus bradycardia and high heart rate variability in active subjects, and suggest that exercise training induces adaptations in autonomic cardiovascular control. Alternatively, data from cross-sectional studies leave open the possibility that individuals with a genetic predisposition for lower heart rates or greater heart rate variability are also endowed with greater aerobic capacity. Conflicting results from a limited number of exercise training studies fail to conclusively demonstrate a direct effect of exercise training on the autonomic nervous system. In this report I suggest that simple measures of heart rate variability during controlled frequency breathing, and arterial baroreceptor responsiveness to Valsalva's maneuver provide unique insights into autonomic regulation of cardiovascular function. I propose that systemic-wide integration of exercise training effects might be better characterized if exercise physiologists would perform tests of autonomic function in conjunction with standard exercise tests during routine laboratory evaluations.

WILLIAM H. COOKE

1998-01-01

245

Heart rate variability, overnight urinary norepinephrine, and plasma cholesterol in apparently healthy human adults.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The aim of this study was to assess the relationship between autonomic nervous system activity as indexed by measures of heart rate variability and overnight urinary norepinephrine, and plasma cholesterol levels in a large sample of working adults. METHODS: The study population comprised 611 apparently healthy employees of an airplane manufacturing plant in Southern Germany. Heart rate variability was calculated as beat-to-beat intervals over the course of one 24-hour weekday measured with an ambulatory ECG recorder. Overnight urine collection and blood samples were also obtained. RESULTS: We found an inverse association between indices of vagally-mediated heart rate variability and plasma levels of total cholesterol, low density lipoprotein (LDL), and the ratio of LDL to high density lipoprotein (HDL) that remained significant in multivariate models after controlling for relevant covariates including norepinephrine. Urinary norepinephrine was not significantly related to any measure of cholesterol in multivariate models. CONCLUSIONS: We report here for the first time, in a large sample of healthy human adults, evidence supporting the hypothesis of a clinically relevant inverse relationship between measures of plasma cholesterol and vagally-mediated heart rate variability after controlling for sympathetic nervous system activity. This suggests an important role for the vagal control of plasma cholesterol levels in cardiovascular disease.

Thayer JF; Fischer JE

2013-01-01

246

[Heart rate and blood pressure are not good parameters to evaluate preoperative anxiety.].  

UK PubMed Central (United Kingdom)

BACKGROUND AND OBJECTIVES: Surgical patients are subject to different levels of preoperative distress. Anxious patients may present unfavorable psychophysical reactions, such as hypertension and tachycardia. This study aimed at evaluating the level of preoperative anxiety in a population of surgical patients, and at detecting heart rate and blood pressure changes and their relationship with age, gender, education and previous surgical experience. METHODS: Participated in this randomized study 145 adult patients of both genders, physical status ASA I - III, perfectly oriented in time and space, literate and scheduled for elective surgeries, to whom the Amsterdam preoperative anxiety questionnaire was applied during preanesthetic evaluation. Patients with scores > 11 were considered anxious. Age, gender, education, systolic and diastolic blood pressure, heart rate, previous surgical experience and history of hypertension were recorded. RESULTS: Sixty-nine patients (47.58%) were considered anxious, while 76 (52.41%) were considered not anxious. There were no significant differences between anxious and non-anxious patients in age, systolic and diastolic blood pressure, and heart rate. Among anxious patients 68.12% were females and 31.88% were males (p < 0.05). There were no significant differences in education, previous surgical experience and history of hypertension between anxious and non-anxious patients. CONCLUSIONS: Heart rate and blood pressure do not reflect the level of preoperative anxiety. Females are more anxious then males in the preoperative period.

Conceição DB; Schonhorst L; Conceição MJ; Oliveira Filho GR

2004-12-01

247

Influence of blood glucose on heart rate and cardiac autonomic function. The DESIR study.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

OBJECTIVES: To evaluate in a general population, the relationships between dysglycaemia, insulin resistance and metabolic variables, and heart rate, heart rate recovery and heart rate variability. METHODS: Four hundred and forty-seven participants in the Data from an Epidemiological Study on the Ins...

Valensi, Paul; Extramiana, Fabrice; Lange, Céline; Cailleau, Martine; Haggui, Abdeddayem; Maison Blanche, Pierre

248

Patients with uncomplicated coronary artery disease have reduced heart rate variability mainly affecting vagal tone  

Digital Repository Infrastructure Vision for European Research (DRIVER)

AIM—To investigate whether uncomplicated chronic coronary artery disease causes changes in heart rate variability and if so, whether the heart rate variability pattern is different from that described in patients with acute myocardial infarction.?METHODS—Heart rate variability was studied in 65 pati...

Wennerblom, B; Lurje, L; Tygesen, H; Vahisalo, R; Hjalmarson, A

249

Making the Most of the "Daphnia" Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine  

Science.gov (United States)

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…

Corotto, Frank; Ceballos, Darrel; Lee, Adam; Vinson, Lindsey

2010-01-01

250

Higher heart rate increases risk of diabetes among men: The Australian Diabetes Obesity and Lifestyle (AusDiab) Study.  

UK PubMed Central (United Kingdom)

AIMS: A very limited number of prospective studies have reported conflicting data on the relation between heart rate and diabetes risk. Our aim therefore was to determine in a large, national, population-based cohort if heart rate predicts the development of diabetes. METHODS: The Australian Diabetes Obesity and Lifestyle study followed up 6537 people over 5 years. Baseline measurements included questionnaires, anthropometrics and blood and urine collection. Heart rate was recorded in beats per min (Dinamap). An oral glucose tolerance test was performed at baseline and follow-up, and diabetes was defined using World Health Organization criteria. RESULTS: A total of 5817 participants were eligible for analysis, 221 of whom developed diabetes. Compared with participants with a heart rate < 60 b min(-1), those with a heart rate ? 80 b min(-1) were more likely to develop diabetes (odds ratio 1.89, 95% CI 1.07-3.35) over 5 years, independent of traditional risk factors. This relationship was highly significant, particularly in non-obese men (odds ratio 5.61, 95% CI 1.75-17.98), but not in their obese counterparts or in women. CONCLUSIONS: Resting heart rate is associated with an increased risk of diabetes over a 5-year period, particularly among non-obese men. This suggests that sympathetic overactivity may be a contributing factor to the development of diabetes, and that resting heart rate may be useful in predicting risk of Type 2 diabetes in non-obese men.

Grantham NM; Magliano DJ; Tanamas SK; Söderberg S; Schlaich MP; Shaw JE

2013-04-01

251

Study of foetal heart rate patterns in pregnancy with intra-uterine growth restriction during antepartum period.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To evaluate foetal heart rate pattern during antepartum period in pregnancies suffering from intrauterine growth restriction. METHODS: The case control study was conducted at the Alzahra Hospital, Tabriz, Iran from April 2008 to April 2011. It comprised 100 pregnancies with intra-uterine growth restriction and 92 normal pregnancies. The foetal heart rate pattern including basal heart rate, beat-to-beat variation, non-stress test (NST) result and acceleration and deceleration patterns of the heart rate were determined in both groups during the antepartum period. Findings were compared between the two groups and their relation with pregnancy-foetal outcomes was specified in the case group. SPSS 15 was used for statistical analysis. RESULTS: There was no statistically significant difference between the foetus mean basal heart rate in the two groups (p <0.960). Frequency of cases with non-reactive non-stress test in the Cases was significantly higher than Controls (p <0.005). The difference in heart rate acceleration was also not statistically significant (p <0.618). Frequency of cases with low birth weight and caesarian was non-significantly but borderline higher among the Cases (p <0.081 and 0.060, respectively). CONCLUSION: Abnormal foetal heart rate pattern is more common in pregnancies marked by intra-uterine growth restriction and is directly associated with worse pregnancy/foetal outcomes.

Fardiazar Z; Abad NM; Abassalizade F; Torab R; Goldust M

2013-07-01

252

Heart rate variability abnormalities in young patients with dilated cardiomyopathy.  

Science.gov (United States)

Heart rate variability (HRV) has become the conventionally accepted term for describing variations in both instantaneous heart rate and R-R intervals. In the pediatric age group, HRV has been investigated in healthy children, diabetics, respiratory distress syndrome of the newborn, and sudden infant death syndrome. This study aimed to evaluate HRV in pediatric patients with dilated cardiomyopathy and to compare it with that of age-matched normal subjects. The study evaluated 21 patients with dilated cardiomyopathy: 11 females (mean age, 7 ± 4 years; range, 2-17 years) and 10 males (mean age, 10 ± 6 years; range, 2-18 years). Dilated cardiomyopathy (DCM) was diagnosed according to commonly accepted criteria after a noninvasive cardiologic examination, echocardiography, and 24-h Holter monitoring (MR45 and MR45-3 Oxford recorder). The patients were divided into six groups according to age, sex, and type of cardiomyopathy. Heart rate variability was recorded and analyzed in the time domain. The patients with DCM showed an abnormal HRV pattern. Particularly in the 5-6-year-old male patient group, the HRV values all were significantly increased (p = 0.05). In the 2-6-year-old female patient group, the mean cycle length, the standard deviation of all normal sinus R-R intervals during 24 h (SDNN), and the standard deviation of the average normal sinus R-R intervals for all 5-min segments (SDANN) were significantly increased (p = 0.05). The 13-18-year-old female patient group showed a significant reduction in SDNN and the mean of the standard deviation of all normal sinus R-R intervals for all 5-min segments (SDNNi) (p = 0.05). The modification of the HRV pattern in the time domain, partially age- and gender-dependent modification, may reflect an imbalance of the autonomic nervous system in children who show a delayed or reduced activity, such as pediatric patients with DCM. PMID:22411717

Grutter, Giorgia; Giordano, Ugo; Alfieri, Sara; Iodice, Francesca; Drago, Fabrizio; Ravà, Lucilla; Silvetti, Massimo Stefano

2012-03-13

253

Heart rate variability abnormalities in young patients with dilated cardiomyopathy.  

UK PubMed Central (United Kingdom)

Heart rate variability (HRV) has become the conventionally accepted term for describing variations in both instantaneous heart rate and R-R intervals. In the pediatric age group, HRV has been investigated in healthy children, diabetics, respiratory distress syndrome of the newborn, and sudden infant death syndrome. This study aimed to evaluate HRV in pediatric patients with dilated cardiomyopathy and to compare it with that of age-matched normal subjects. The study evaluated 21 patients with dilated cardiomyopathy: 11 females (mean age, 7 ± 4 years; range, 2-17 years) and 10 males (mean age, 10 ± 6 years; range, 2-18 years). Dilated cardiomyopathy (DCM) was diagnosed according to commonly accepted criteria after a noninvasive cardiologic examination, echocardiography, and 24-h Holter monitoring (MR45 and MR45-3 Oxford recorder). The patients were divided into six groups according to age, sex, and type of cardiomyopathy. Heart rate variability was recorded and analyzed in the time domain. The patients with DCM showed an abnormal HRV pattern. Particularly in the 5-6-year-old male patient group, the HRV values all were significantly increased (p = 0.05). In the 2-6-year-old female patient group, the mean cycle length, the standard deviation of all normal sinus R-R intervals during 24 h (SDNN), and the standard deviation of the average normal sinus R-R intervals for all 5-min segments (SDANN) were significantly increased (p = 0.05). The 13-18-year-old female patient group showed a significant reduction in SDNN and the mean of the standard deviation of all normal sinus R-R intervals for all 5-min segments (SDNNi) (p = 0.05). The modification of the HRV pattern in the time domain, partially age- and gender-dependent modification, may reflect an imbalance of the autonomic nervous system in children who show a delayed or reduced activity, such as pediatric patients with DCM.

Grutter G; Giordano U; Alfieri S; Iodice F; Drago F; Ravà L; Silvetti MS

2012-10-01

254

Influence of heart rate on mortality after acute myocardial infarction.  

UK PubMed Central (United Kingdom)

Elevated heart rate (HR) during hospitalization and after discharge has been predictive of death in patients with acute myocardial infarction (AMI), but whether this association is primarily due to associated cardiac failure is unknown. The major purpose of this study was to characterize in 1,807 patients with AMI admitted into a multicenter study the relation of HR to in-hospital, after discharge and total mortality from day 2 to 1 year in patients with and without heart failure. HR was examined on admission at maximum level in the coronary care unit, and at hospital discharge. Both in-hospital and postdischarge mortality increased with increasing admission HR, and total mortality (day 2 to 1 year) was 15% for patients with an admission HR between 50 and 60 beats/min, 41% for HR greater than 90 beats/min and 48% for HR greater than or equal to 110 beats/min. Mortality from hospital discharge to 1 year was similarly related to maximal HR in the coronary care unit and to HR at discharge. In patients with severe heart failure (grade 3 or 4 pulmonary congestion on chest x-ray, or shock), cumulative mortality was high regardless of the level of admission HR (range 61 to 68%). However, in patients with pulmonary venous congestion of grade 2, cumulative mortality for patients with admission HR greater than or equal to 90 beats/min was over twice as high as that in patients with admission HR less than 90 beats/min (39 vs 18%, respectively); the same trend was evident in patients with absent to mild heart failure (mortality 18 vs 10%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Hjalmarson A; Gilpin EA; Kjekshus J; Schieman G; Nicod P; Henning H; Ross J Jr

1990-03-01

255

Influence of heart rate on mortality after acute myocardial infarction.  

Science.gov (United States)

Elevated heart rate (HR) during hospitalization and after discharge has been predictive of death in patients with acute myocardial infarction (AMI), but whether this association is primarily due to associated cardiac failure is unknown. The major purpose of this study was to characterize in 1,807 patients with AMI admitted into a multicenter study the relation of HR to in-hospital, after discharge and total mortality from day 2 to 1 year in patients with and without heart failure. HR was examined on admission at maximum level in the coronary care unit, and at hospital discharge. Both in-hospital and postdischarge mortality increased with increasing admission HR, and total mortality (day 2 to 1 year) was 15% for patients with an admission HR between 50 and 60 beats/min, 41% for HR greater than 90 beats/min and 48% for HR greater than or equal to 110 beats/min. Mortality from hospital discharge to 1 year was similarly related to maximal HR in the coronary care unit and to HR at discharge. In patients with severe heart failure (grade 3 or 4 pulmonary congestion on chest x-ray, or shock), cumulative mortality was high regardless of the level of admission HR (range 61 to 68%). However, in patients with pulmonary venous congestion of grade 2, cumulative mortality for patients with admission HR greater than or equal to 90 beats/min was over twice as high as that in patients with admission HR less than 90 beats/min (39 vs 18%, respectively); the same trend was evident in patients with absent to mild heart failure (mortality 18 vs 10%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1968702

Hjalmarson, A; Gilpin, E A; Kjekshus, J; Schieman, G; Nicod, P; Henning, H; Ross, J

1990-03-01

256

Neural Network Analysis and Evaluation of the Fetal Heart Rate  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the present study is to obtain a highly objective automatic fetal heart rate (FHR) diagnosis. The neural network software was composed of three layers with the back propagation, to which 8 FHR data, including sinusoidal FHR, were input and the system was educated by the data of 20 cases with a known outcome. The output was the probability of a normal, intermediate, or pathologic outcome. The neural index studied prolonged monitoring. The neonatal states and the FHR score strongly correlated with the outcome probability. The neural index diagnosis was correct. The completed software was transferred to other computers, where the system function was correct.

Yasuaki Noguchi; Fujihiko Matsumoto; Kazuo Maeda; Takashi Nagasawa

2009-01-01

257

Telemetered heart rate as an index of energy expenditure in moose (Alces alces).  

UK PubMed Central (United Kingdom)

Metabolic rate, heart rate and respiratory rate of three adult moose were monitored simultaneously on selected days between January 1982 and October 1983. Heart rate was successfully monitored using two types of implanted radio transmitters. Metabolic rate was significantly (P less than 0.001) correlated with heart rate for individual animals (r = 0.94-0.98). The relationship was best described by an exponential equation. A mean weighted equation predicted metabolic rate within 9% of individual equations. In adult moose cows, heart rate was a more reliable predictor of energy expenditure than respiratory rate.

Renecker LA; Hudson RJ

1985-01-01

258

Stress biomarkers in children: heart rate variability versus salivary cortisol  

Directory of Open Access Journals (Sweden)

Full Text Available Rationale/statement of the problem : Stress is a complex phenomenon coordinated by several neural systems and has consequently been measured by several biomarkers. Salivary cortisol is the classical used stress biomarker representing the hypothalamic-pituitary-adrenal system. Heart rate variability (HRV), defined as the distance variability between consecutive R peaks, is increasingly used as marker of the autonomic nervous system and as a result also as a stress marker (defined as sympathetic over parasympathetic dominance). Associations between children's salivary cortisol and HRV will be examined. Methods : In 190 children (5–10 year) of the Belgian ChiBS study salivary cortisol and HRV were sampled. Salivary cortisol samples were collected when waking up, 30 minutes and 60 minutes after wake-up and in the evening on two weekdays. HRV measurements in supine position were undertaken with Polar chest belts during 5 minutes. Apart from HRV time-domain analysis, also frequency-domain analysis was performed in the low-frequency (LF) and high-frequency (HF) bands. Multilevel growth curve modelling with adjustments for age, sex, physical activity and wake-up time was used to analyse the HRV associations with overall cortisol, cortisol awakening response (CAR) and cortisol diurnal decline. Results : Higher overall cortisol levels were negatively associated with mean RR, root mean square of successive differences (RMSSD), percentage of RR intervals differing more than 5 0ms (pNN50) and HF. A steeper diurnal decline was positively associated with normalised LF and the LF/HF ratio and negatively with HF. The CAR was positively associated with normalised LF and the LF/HF ratio and negatively with normalised HF. Conclusion : Higher salivary cortisol levels were associated with lower parasympathetic activity. A larger CAR and steeper diurnal decline were associated with a sympathetic over parasympathetic dominance. Consequently, the two main neural stress systems (represented by cortisol and HRV) show good agreement in reflecting children's stress status, although not all parameters were significantly related. Measuring both pathways stays recommended as the pathways might be stimulated differently depending on the stressor.

Nathalie Michels; Els Clays; Marc de Buyzere; Inge Huybrechts; Barbara Vanaelst; Stefaan de Henauw; Isabelle Sioen

2012-01-01

259

Impact of basal heart rate on long-term prognosis of heart transplant patients.  

UK PubMed Central (United Kingdom)

Previous studies in patients with heart failure have shown that an elevated basal heart rate (HR) is associated with a poor outcome. Our aim with this study was to investigate if this relationship is also present in heart transplantation (HTx) recipients. From 2003 until 2010, 256 HTx performed in our center were recruited. Patients who required pacemaker, heart-lung transplants, pediatrics, retransplants, and those patients with a survival of less than 1 year were excluded. The final number included in the analysis was 191. Using the HR obtained by EKG during elective admission at 1 year post-HTx and the survival rate, an ROC-curve was performed. The best point under the curve was achieved with 101 beats per minute (bpm), so patients were divided in two groups according to their HR. A comparison between survival curves of both groups was performed (Kaplan-Meier). Subsequently, a multivariate analysis considering HR and other variables with influence on survival according to the literature was carried out. A total of 136 patients were included in the group with HR ?100 bpm, and 55 in the one with HR >100 bpm. There were no basal differences in both groups except for primary graft failure, which was more frequent in the >100 bpm group (30.9 vs. 17%, P = 0.033). Patients with ?100 bpm had a better long prognosis (P < 0.001). The multivariate analysis proved that high HR was an independent predictor of mortality. Our study shows that HR should be considered as a prognosis factor in HTx patients.

Melero-Ferrer JL; Sánchez-Lázaro IJ; Almenar-Bonet L; Martínez-Dolz L; Buendía-Fuentes F; Portolés-Sanz M; Rivera-Otero M; Salvador-Sanz A

2013-05-01

260

Validity and reliability of Polar® RS800CX heart rate monitor, measuring heart rate in dogs during standing position and at trot on a treadmill.  

UK PubMed Central (United Kingdom)

UNLABELLED: The aim of the present study was to assess criterion validity, and relative and absolute reliability of Polar® RS800CX heart rate monitor, compared to simultaneously recorded electrocardiogram (ECG) data, in measuring heart rate of dogs during standing position and at trot on a treadmill. METHODS: Heart beats from Polar® RS800CX and Cardiostore ECG were recorded simultaneously during seven continuous minutes in standing position and at trot, in 10 adult healthy dogs. Polar® data was statistically compared to ECG data for a variety of mean beats per minute (BPM), standard deviation and confidence interval. Criterion validity was calculated by Pearson product moment correlation method and intraclass correlation coefficient (ICC2.1). Relative and absolute reliability were calculated by ICC2.1, the Bland and Altman analysis and standard error of measurement (SEM and SEM%). RESULTS: The correlation, criterion validity, between Polar® and ECG data in standing position was r=0.99 (p<0.0005) and at trot r=0.97 (p<0.0005). Polar® data was not significantly different from ECG data. Mean difference between ECG and uncorrected Polar® data was -0.6 BPM in standing position and -0.6 BPM at trot. Polar® was over- and underestimating ECG data. SEM and SEM% in standing were ±2.6 BPM and 3.0%, at trot ±3.8 BPM and 3.1%, indicating that measurement errors were low. CONCLUSION: This study showed that the criterion validity and the instrument reliability were excellent in Polar® RS800CX heart rate measuring system. The equipment seemed to be valid and reliable in measuring BPM in the dogs studied during submaximal cardiovascular conditions such as in standing position and at trot on a treadmill.

Essner A; Sjöström R; Ahlgren E; Lindmark B

2013-04-01

 
 
 
 
261

Circadian periodicity of heart rate variability in hospitalized angor patients.  

UK PubMed Central (United Kingdom)

The relationship between unstable angor (angina) and circadian periodicity of heart rate variability (HRV) was explored in a group of patients hospitalized in a coronary care unit (CCU). Patients were classified as normal (whose symptoms had non-cardiovascular origin, n=8), moderate angor (n=13) and severe angor (n=11). A fourth group of ambulatory healthy volunteers (n=12) was included. Individual 24 h Holter records were analyzed, mean RR and standard deviation of RR (SDNN) being obtained from 1 h-length windows. For frequency domain analysis, 5 min-length windows were employed. The spectral components analyzed were total power (spectral power between 0.01 and 0.5 Hz), low frequency power (LF: power between 0.04 and 0.15 Hz), and high frequency power (HF: power between 0.15 and 0.4 Hz). In addition, LF to HF areas ratio (L/H) was computed. Mesor, amplitude and acrophase for every 24 h rhythm were calculated by cosinor analysis. As compared to ambulatory controls, admission to the CCU diminished amplitude and phase-delayed the circadian oscillation of most HRV parameters, except for SDNN. Moderate angor patients showed decreased amplitude of RR and L/H and augmented amplitude of SDNN when compared to normal hospitalized subjects. A phase delay of about 1.5 h for RR intervals and a phase advance of 3.5-6 h for LFA and SDNN were found in the moderate angor group when compared to normal. Amplitude of 24 h variation of total power decreased in severely angor patients and the circadian oscillation of HF (an indicator of vagal control on the heart) became free running. A phase delay of 2.5 h in SDNN acrophase was found in severely affected patients when compared to moderate. The results indicate that severity of unstable angor correlates with desynchronization of parasympathetic control of heart rate.

D'Negri CE; Marelich L; Vigo D; Acunzo RS; Girotti LA; Cardinali DP; Siri LN

2005-06-01

262

Circadian periodicity of heart rate variability in hospitalized angor patients.  

Science.gov (United States)

The relationship between unstable angor (angina) and circadian periodicity of heart rate variability (HRV) was explored in a group of patients hospitalized in a coronary care unit (CCU). Patients were classified as normal (whose symptoms had non-cardiovascular origin, n=8), moderate angor (n=13) and severe angor (n=11). A fourth group of ambulatory healthy volunteers (n=12) was included. Individual 24 h Holter records were analyzed, mean RR and standard deviation of RR (SDNN) being obtained from 1 h-length windows. For frequency domain analysis, 5 min-length windows were employed. The spectral components analyzed were total power (spectral power between 0.01 and 0.5 Hz), low frequency power (LF: power between 0.04 and 0.15 Hz), and high frequency power (HF: power between 0.15 and 0.4 Hz). In addition, LF to HF areas ratio (L/H) was computed. Mesor, amplitude and acrophase for every 24 h rhythm were calculated by cosinor analysis. As compared to ambulatory controls, admission to the CCU diminished amplitude and phase-delayed the circadian oscillation of most HRV parameters, except for SDNN. Moderate angor patients showed decreased amplitude of RR and L/H and augmented amplitude of SDNN when compared to normal hospitalized subjects. A phase delay of about 1.5 h for RR intervals and a phase advance of 3.5-6 h for LFA and SDNN were found in the moderate angor group when compared to normal. Amplitude of 24 h variation of total power decreased in severely angor patients and the circadian oscillation of HF (an indicator of vagal control on the heart) became free running. A phase delay of 2.5 h in SDNN acrophase was found in severely affected patients when compared to moderate. The results indicate that severity of unstable angor correlates with desynchronization of parasympathetic control of heart rate. PMID:15944873

D'Negri, Carlos E; Marelich, Liliana; Vigo, Daniel; Acunzo, Rafael S; Girotti, Luis A; Cardinali, Daniel P; Siri, Leonardo Nicola

2005-06-01

263

Atenolol is associated with lower day-of-surgery heart rate compared to long- and short-acting metoprolol.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The authors analyzed the association between outpatient ?-blocker type and day-of-surgery (DOS) heart rate in ambulatory surgical patients. They further investigated whether differences in DOS heart rate between atenolol and metoprolol could be explained by once-daily versus twice-daily dosing regimens. DESIGN: Retrospective observational study. SETTING: Veterans Administration hospital. PARTICIPANTS: Ambulatory surgical patients on long-term atenolol or metoprolol. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Using a propensity-score-matched cohort, DOS heart rates were compared in patients prescribed atenolol versus metoprolol. Then, once-daily and twice-daily metoprolol formulations were differentiated and DOS heart rates were compared within a general linear model. DOS heart rates in patients prescribed atenolol versus any metoprolol formulation were slower by a mean of 5.1 beats/min (66.6 v 71.7; 95% confidence interval [CI] of difference, 1.9-8.3; p = 0.002), a difference that was not observed in preoperative primary care visits. The general linear model showed that patients prescribed atenolol (typically once-daily dosing) had a mean DOS heart rate 5.6 beats/min lower compared with patients prescribed once-daily metoprolol succinate (68.9 v 74.5; 95% CI of difference, -8.6 to -2.6; p < 0.001) and 3.8 beats/min lower compared with patients prescribed twice-daily metoprolol tartrate (68.9 v 72.7; 95% CI of difference, -6.1 to -1.6; p < 0.001). DOS heart rates were similar between different formulations of metoprolol (95% CI of difference, -1.0 to +4.6; p = 0.22). CONCLUSIONS: Atenolol is associated with a lower DOS heart rate versus metoprolol. The heart rate difference is specific to the day of surgery and is not explained by once-daily versus twice-daily dosing regimens.

Schonberger RB; Brandt C; Feinleib J; Dai F; Burg MM

2013-04-01

264

Does heart rate variability change in angina pectoris patients treated with spinal cord stimulation?  

Science.gov (United States)

To determine whether spinal cord stimulation has any effect on the autonomic nervous tone of the heart, heart rate variability was used as an indicator of autonomic nervous control of the heart. The components time domain and power spectral analyses of heart rate variability were measured in 21 patients with angina pectoris. Twenty-four-hour Holter recordings were obtained before and after 12 months with spinal cord stimulation. No significant attenuation of time domain or spectral components of heart rate variability analyses were found. Apparently, spinal cord stimulation does not influence the autonomic tone of the heart. PMID:9452151

Andersen, C

1998-01-01

265

Does heart rate variability change in angina pectoris patients treated with spinal cord stimulation?  

UK PubMed Central (United Kingdom)

To determine whether spinal cord stimulation has any effect on the autonomic nervous tone of the heart, heart rate variability was used as an indicator of autonomic nervous control of the heart. The components time domain and power spectral analyses of heart rate variability were measured in 21 patients with angina pectoris. Twenty-four-hour Holter recordings were obtained before and after 12 months with spinal cord stimulation. No significant attenuation of time domain or spectral components of heart rate variability analyses were found. Apparently, spinal cord stimulation does not influence the autonomic tone of the heart.

Andersen C

1998-01-01

266

Heart-rate variability and precompetitive anxiety in swimmers.  

UK PubMed Central (United Kingdom)

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.

Cervantes Blásquez JC; Rodas Font G; Capdevila Ortís L

2009-11-01

267

Importance of heart rate analysis in exercise tolerance test  

Directory of Open Access Journals (Sweden)

Full Text Available After many years away from the limelights, at the beginning of this century, exercise tolerance testing has earned back an important position in international medical journals. The different sorts of information derived from a variety of studies based on it have shown us that this propedeutic method has a highly valuable prognostic impact. Because of its low cost and easy applicability, the exercise testing reinforces its position in the clinical practice of the cardiologist. In the early 70's, research relating the influence of the autonomic nervous system in heart rate behavior in all phases of an exercise tolerance testing began. Ever since, a number of hypotheses tried to clarify which would be the mechanisms related to the chronotropic response during effort and its performance in the recovery period. In this updating article the authors deal with an important data referring to the chronotropic deficit and the abnormal heart rate recovery, commenting on the prognostic implication of keeping the focus on the potential of its clinical impact. In other words, approaches that can be used whenever there is someone performing a monitored exercise tolerance testing.

Herdy Artur Haddad; Fay Carlos Eduardo Schio; Bornschein Christian; Stein Ricardo

2003-01-01

268

HEART RATE AND MOTION ANALYSIS BY GPS IN BEACH SOCCER  

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Full Text Available Although beach soccer has become increasingly popular in recent years very little scientific research has been conducted into the sport. A pilot study was carried out with the aim of examining the physiological (heart rate) and physical (motion analysis) responses of beach soccer players during competitive matches. Ten players (age 25.5 ± 0.5 years; height 1.80 ± 0.08 m; weight 78.2 ± 5.6 kg.) were studied over five beach soccer matches. The physiological demands were analysed by measuring heart rate (HR) using telemetric devices, while the physical profile was evaluated by recording motion and speed by means of GPS devices. During competitive matches, players obtained a HRmean of 165.2 bpm (86.5% HRmax), with 59.3% of the time participating (TP) corresponding to values above 90% of the HRmax. The distance covered per minute of participation was 97.7 m, with 9.5% of this distance corresponding to high-intensity running and 2.5% to sprint; the work:rest ratio was 1.4:1 and the maximum speed 21.7 km·h-1. These results showed that beach soccer is an intermittent physical activity of greater intensity than other team games. It requires a major contribution from the anaerobic system as emphasis is placed on players making quick bursts of high-intensity activity separated by brief rest periods

Julen Castellano; David Casamichana

2010-01-01

269

Heart rate monitoring and control in altered gravity conditions.  

UK PubMed Central (United Kingdom)

On the basis of indirect evidences it has been hypothesized that during space missions the almost complete absence of gravity might impair the baroreflex control of circulation. In the first part of this paper we report results obtained from a series of experiments carried out to directly verify this hypothesis during the 16-day STS 107 Shuttle flight. Spontaneous baroreflex sensitivity was assessed in four astronauts before flight (baseline) and at days 0-1, 6-7 and 12-13 during flight, both at rest and while performing moderate exercise. Our results indicate that at rest the baroreflex sensitivity significantly increased in the early flight phase, as compared to pre-flight values and tended to return to baseline in the mid-late phase of flight. During exercise, baroreflex sensitivity was lower than at rest, without any difference among pre-flight and in-flight values. These findings seem to exclude the hypothesis of an impairment of the baroreflex control of heart rate during exposure to microgravity, at least over a time window of 16 days. In the second part of the paper we propose a novel textile-based methodology for heart rate and other vital signs monitoring during gravity stress. The positive results obtained from its use during parachute jumps support the use of smart garments for the unobtrusive assessment of physiological parameters in extreme environments.

Di Rienzo M; Parati G; Rizzo F; Meriggi P; Merati G; Faini A; Castiglioni P

2007-01-01

270

Assessment of cardiac autonomic functions by heart rate recovery, heart rate variability and QT dynamicity parameters in patients with acromegaly.  

UK PubMed Central (United Kingdom)

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 acromegaly.

Dural M; Kabakc? G; C?nar N; Erba? T; Canpolat U; Gürses KM; Tokgözo?lu L; Oto A; Kaya EB; Yorgun H; Sahiner L; Da?delen S; Aytemir K

2013-04-01

271

Regulation of ?-adrenergic control of heart rate by GTP-cyclohydrolase 1 (GCH1) and tetrahydrobiopterin.  

UK PubMed Central (United Kingdom)

AIMS: Clinical markers of cardiac autonomic function, such as heart rate and response to exercise, are important predictors of cardiovascular risk. Tetrahydrobiopterin (BH4) is a required cofactor for enzymes with roles in cardiac autonomic function, including tyrosine hydroxylase and nitric oxide synthase. Synthesis of BH4 is regulated by GTP cyclohydrolase I (GTPCH), encoded by GCH1. Recent clinical studies report associations between GCH1 variants and increased heart rate, but the mechanistic importance of GCH1 and BH4 in autonomic function remains unclear. We investigate the effect of BH4 deficiency on the autonomic regulation of heart rate in the hph-1 mouse model of BH4 deficiency. METHODS AND RESULTS: In the hph-1 mouse, reduced cardiac GCH1 expression, GTPCH enzymatic activity, and BH4 were associated with increased resting heart rate; blood pressure was not different. Exercise training decreased resting heart rate, but hph-1 mice retained a relative tachycardia. Vagal nerve stimulation in vitro induced bradycardia equally in hph-1 and wild-type mice both before and after exercise training. Direct atrial responses to carbamylcholine were equal. In contrast, propranolol treatment normalized the resting tachycardia in vivo. Stellate ganglion stimulation and isoproterenol but not forskolin application in vitro induced a greater tachycardic response in hph-1 mice. ?1-adrenoceptor protein was increased as was the cAMP response to isoproterenol stimulation. CONCLUSION: Reduced GCH1 expression and BH4 deficiency cause tachycardia through enhanced ?-adrenergic sensitivity, with no effect on vagal function. GCH1 expression and BH4 are novel determinants of cardiac autonomic regulation that may have important roles in cardiovascular pathophysiology.

Adlam D; Herring N; Douglas G; De Bono JP; Li D; Danson EJ; Tatham A; Lu CJ; Jennings KA; Cragg SJ; Casadei B; Paterson DJ; Channon KM

2012-03-01

272

Heart rate variability on antihypertensive drugs in Black patients living in sub-Saharan Africa.  

UK PubMed Central (United Kingdom)

Background. Compared with Caucasians, African Americans have lower heart rate variability (HRV) in the high-frequency domain, but there are no studies in Blacks born and living in Africa. Methods. In the Newer versus Older Antihypertensive agents in African Hypertensive patients trial (NCT01030458), patients (30-69 years) with uncomplicated hypertension (140-179/90-109 mmHg) were randomized to single-pill combinations of bisoprolol/hydrochlorothiazide (R) or amlodipine/valsartan (E). 72 R and 84 E patients underwent 5-min ECG recordings at randomization and 8, 16 and 24 weeks. HRV was determined by fast Fourier transform and autoregressive modelling. Results. Heart rate decreased by 9.5 beats/min in R patients with no change in E patients (- 2.2 beats/min). R patients had reduced total (- 0.13 ms²; p = 0.0038) and low-frequency power (- 3.6 nu; p = 0.057), higher high-frequency (+ 3.3 nu; p = 0.050) and a reduced low- to high-frequency ratio (- 0.08; p = 0.040). With adjustment for heart rate, these differences disappeared, except for the reduced low-frequency power in the R group (- 4.67 nu; p = 0.02). Analyses confined to 39 R and 47 E patients with HRV measurements at all visits or based on autoregressive modelling were confirmatory. Conclusion. In native Black African patients, antihypertensive drugs modulate HRV, an index of autonomous nervous tone. However, these effects were mediated by changes in heart rate except for low-frequency variability, which was reduced on beta blockade independent of heart rate.

Osakwe CE; Jacobs L; Anisiuba BC; Ndiaye MB; Lemogoum D; Ijoma CK; Kamdem MM; Thijs L; Boombhi HJ; Kaptue J; Kolo PM; Mipinda JB; Odili AN; Ezeala-Adikaibe B; Kingue S; Omotoso BA; Ba SA; Ulasi II; M'buyamba-Kabangu JR; Staessen JA

2013-09-01

273

Impact of caffeine on heart rate and blood pressure at rest and during exercise  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction:Several studies have evaluated the impact of caffeine consumption on athletes performance from different aspects; however, the findings are varied. The aim of this research was to evaluate the impact of caffeine consumption on some of the cardiovascular factors including heart rate and blood pressure at rest, at the end of exercise, and during the 3rd and 5th minutes of recovery. Material and Methods:The subjects of this study included 20 female athletes, voluntarily participating in the study. Two separate tests with an interval of one week were conducted. The subjects received placebo for the first test and caffeine containing capsules (5 mg/kg) for the second test. The patient heart rate and blood pressure were measured at rest, at the end of the exercise and during the 3rd and 5th minutes of recovery after submaximal test. Maximal oxygen consumption (VO2max) was measured using Fax submaximal cardiorespiratory test. Paired t- test was used for data analysis. Results:Caffeine consumption had no significantly effect on VO2max, resting and end exercise heart rate, and blood pressure recorded at the end of the exercise. Caffeine consumption caused a significant increase in the heart rate during 3rd and 5th minutes of recovery, and in blood pressure at rest, and during the 3rd and the 5th minutes of recovery in the athletes. Conclusion:Due to the caffeine induced increase in blood pressure and heart rate, caffeine consumption (5 mg/kg) before submaximal exercise is not recommended either for those who suffer hypertension or cardiac disease nor for those who do exercise for health or athletic purposes.

Azam Mousavi; Maryam Koushki Jahromi; Mohsen Salesi; Farhad Daryanoush; Ebrahim Khoshnam; Asghar Nikseresht; Ebrahim Hemati

2011-01-01

274

[Heart rate reduction: beneficial effects in heart failure and post-infarcted myocardium].  

UK PubMed Central (United Kingdom)

Heart rate (HR) is an independent predicting factor of cardiovascular events in patients with advanced heart failure. Clinical trials conducted with beta-blockers have demonstrated that reduction of HR is a fundamental mechanism to explain the reduction of morbidity-mortality in such a disease. Trials conducted with ivabradine, the first selective inhibitor of the I(f) current in cardiac pacemaker cells, have also clearly confirmed that reduction of HR lead to powerful and sustained favourable effects in patients with cardiac failure and post-infarcted myocardial diseases. These effects are not only due to the reduction of the risk factors associated with myocardial ischemia but also to the reduction of cardiac and perivascular fibrosis associated with the remodelling process at the ventricular level. Although the mechanisms associated with reduction of HR following administration of beta-blockers and ivabradine are to a large extent similar, others like their effects on post-systolic contraction are totally opposed. So, new clinical trials are necessary to know whether it is possible to substitute these drugs or conversely to associate them for an optimal therapeutic strategy in patients with advanced heart failure and post-infarcted myocardium.

Berdeaux A; Tissier R; Couvreur N; Salouage I; Ghaleh B

2009-03-01

275

Effects of aerobic exercise training on 24 hr profile of heart rate variability in female athletes.  

UK PubMed Central (United Kingdom)

BACKGROUND: The aim of this study was to investigate the effects of exercise training on autonomic regulation of heart rate under daily life conditions. METHODS: Twenty-six healthy female athletes (age 24.5 +/- 1.9 yrs) involved in regular physical activity were recruited during a period of yearly rest and randomly assigned to a five-week aerobic exercise training program (n = 13) or to a non-exercise control group (n = 13). MEASURES: Before and after the five-week training, all subjects underwent a bycicle ergometer stress test and a 24-hour dynamic ECG monitoring. Autonomic regulation of heart rate has been investigated by means of both time and frequency domain analyses of heart rate variability (HRV). Spectral analysis of R-R interval variability (autoregressive algorithm) provided markers of sympathetic (low frequency, LF, 0.10 Hz) and parasympathetic (high frequency, HF, 0.25 Hz) modulation of the sinus node. RESULTS: Trained subjects showed a reduced heart rate response to submaximal workload. Before training there was no significant difference between the two groups. After training resting heart rate did not significantly differ between trained and untrained subjects. No significant differences were observed in the different time domain indexes of heart rate variability. The day-night difference in SD and SDRR were significantly less in the trained as compared to the untrained group. Normalized LF and HF components did not significantly differ between trained and untrained subjects, during the awake period. The decrease in the LF and the increase in the HF component during nighttime were significantly less in the trained group. The LF/HF ratio was significantly decreased during the night in the untrained group whereas it was not significantly different from the awake state in the trained group. CONCLUSIONS: These findings of the relative night-time increase in LF and the decrease in the day-night difference in time domain indexes of heart rate variability suggest that, in young female athletes, exercise training is able to induce an increase in the sympathetic modulation of the sinus node which may coexist with signs of relatively reduced, or unaffected, vagal modulation.

Pigozzi F; Alabiso A; Parisi A; Di Salvo V; Di Luigi L; Spataro A; Iellamo F

2001-03-01

276

Combined effects of depressive symptoms and resting heart rate on mortality: the Whitehall II prospective cohort study.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To examine the combined effects of depressive symptoms and resting heart rate on mortality risk. METHOD: Analysis was performed on data from 5,936 participants in the Whitehall II study with a mean ± SD age of 61 ± 6 years. Depressive symptoms were assessed from 2002 to 2004 using the Center for Epidemiologic Studies Depression Scale (cutoff score for depression at ? 16). Resting heart rate was measured at the same study phase via electrocardiogram. Participants were assigned to 1 of 6 risk-factor groups on the basis of depression status (yes/no) and resting heart rate categories (< 60, 60-80, and > 80 beats/minute [bpm]). All-cause mortality was the main outcome in our analysis. Mean follow-up for mortality was 5.6 years. RESULTS: In mutually adjusted Cox regression models, depression (hazard ratio = 1.93, P < .001) and resting heart rate > 80 bpm (hazard ratio = 1.67, P < .001) were independent predictors of mortality. After adjustment for potential confounding and mediating variables, participants with both depression and high resting heart rate had a 3-fold higher (P < .001) risk of death compared to depression-free participants with resting heart rates ranging from 60 to 80 bpm. This risk is particularly marked in participants with prevalent coronary heart disease. CONCLUSIONS: This study provides evidence that the coexistence of depressive symptoms and elevated resting heart rate is associated with substantially increased risk of death compared to those without these 2 factors. This finding suggests the possibility that treatments that improve both depression and resting heart rate might improve survival.

Nabi H; Kivimäki M; Empana JP; Sabia S; Britton A; Marmot MG; Shipley MJ; Singh-Manoux A

2011-09-01

277

Step and shoot coronary CT angiography using 256-slice CT: effect of heart rate and heart rate variability on image quality  

International Nuclear Information System (INIS)

To evaluate the effect of heart rate variability (HRV) and heart rate (HR) on intra-image ''motion'' and inter-image ''stairstep'' artefacts in step-and-shoot coronary CT angiography (CCTA) using a wide detector CT scanner. 66 patients underwent step-and-shoot CCTA using 256-slice CT. Patients were divided into two groups (Group 1: HR

2011-01-01

278

Newborn infant pain assessment using heart rate variability analysis.  

UK PubMed Central (United Kingdom)

OBJECTIVES: 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. METHODS: 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. RESULTS: 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%. DISCUSSION: 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.

Faye PM; De Jonckheere J; Logier R; Kuissi E; Jeanne M; Rakza T; Storme L

2010-11-01

279

A Comparison of Verapamil and Digoxin for Heart Rate Control in Atrial Fibrillation  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Atrial fibrillation (AF) is one of the most common types of sustained dysrhythmia and there are some disagreements about its treatment. The goals of AF treatment include the control of ventricular rate, the establishment of sinus rhythm and the prevention of thromboembolic events. In this study, the effect of verapamil was compared to digoxin on heart rate control in patients with AF. Methods:This descriptive study was conducted in an emergency department (ED) in Iran. Sixty patients with a new onset AF and rapid ventricular response receiving digoxin or verapamil were included and observed. Results:Two thirty-patient groups receiving verapamil or digoxin were evaluated. The heart rate was significantly decreased in both groups (p = 0.002); however, the cardioversion was not noticed in both of them. The best rate control in verapamil and digoxin groups was observed after 5.9 mg (46.7%) and 0.6 mg (36.7%), respectively. Conclusion: Administration of verapamil in comparison with digoxin has no difference to control the heart rate in AF patients. It should be taken into consideration that prospective randomized studies should be conducted to identify the efficacy and select the best of these two drugs to treat AF patients.

Mohammad Afzali Moghadam; Maryam Fadaie Dashti; Kavous Shahsavarinia; Ata Mahmoodpoor; Kazem Jamali

2012-01-01

280

Blue 405 nm laser light mediates heart rate – investigations at the acupoint Neiguan (Pe.6) in Chinese adults  

Directory of Open Access Journals (Sweden)

Full Text Available Background: In previous studies, we showed that laser needle acupuncture with red and infrared light has specific effects on bio-signals of the brain and heart. Aims: In this publication we report the effect of blue laser light on heart rate and heart rate variability (HRV) before, during and after acupuncture at the acupoint Neiguan (Pe.6) in Chinese adults. These are the first data published concerning heart rate and HRV, obtained with blue laser acupuncture equipment. Patients and Methods: The investigations were carried out in 13 healthy Chinese volunteers with a mean age of 31.2 ± 7.5 years within a randomized, controlled study. Stimulation was performed with painless blue laser light (wavelength: 405 nm; activation: 10 minutes) bilaterally at Pe.6. In a second session, for control reasons the laser was not activated. Results Heart rate showed a significant (p=0.008) decrease during blue laser light stimulation. In contrast, no significant changes were found when the laser was deactivated. The evaluation parameter LF/HF ratio (low frequency/high frequency ratio) from the HRV spectral analysis showed a very slight increase during stimulation, however it was not significant. Conclusions: Our main conclusion is that continuous blue laser light stimulation on Neiguan significantly reduces heart rate of Chinese adults.

Gerhard Litscher; Zheng Xie; Lu Wang; Ingrid Gaischek

2009-01-01

 
 
 
 
281

Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate variability  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english In order to assess the relative influence of age, resting heart rate (HR) and sedentary life style, heart rate variability (HRV) was studied in two different groups. The young group (YG) consisted of 9 sedentary subjects aged 15 to 20 years (YG-S) and of 9 nonsedentary volunteers (YG-NS) also aged 15 to 20. The elderly sedentary group (ESG) consisted of 16 sedentary subjects aged 39 to 82 years. HRV was assessed using a short-term procedure (5 min). R-R variability was ca (more) lculated in the time-domain by means of the root mean square successive differences. Frequency-domain HRV was evaluated by power spectrum analysis considering high frequency and low frequency bands. In the YG the effort tolerance was ranked in a bicycle stress test. HR was similar for both groups while ESG showed a reduced HRV compared with YG. Within each group, HRV displayed a negative correlation with HR. Although YG-NS had better effort tolerance than YG-S, their HR and HRV were not significantly different. We conclude that HRV is reduced with increasing HR or age, regardless of life style. The results obtained in our short-term study agree with others of longer duration by showing that age and HR are the main determinants of HRV. Our results do not support the idea that changes in HRV are related to regular physical activity.

Migliaro, E.R.; Contreras, P.; Bech, S.; Etxagibel, A.; Castro, M.; Ricca, R.; Vicente, K.

2001-04-01

282

Does rating of perceived exertion result in target exercise intensity during interval training in cardiac rehabilitation? A study of the Borg scale versus a heart rate monitor.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To assess whether rating of perceived exertion using the Borg 6-20 scale is a valid method for achieving target exercise intensity during high-intensity interval training in cardiac rehabilitation. DESIGN: A single-group cross-over design. METHODS: Ten participants (56 (6.5) years) who were enrolled in a high-intensity interval training cardiac rehabilitation program were recruited. A target exercise intensity of Borg 17 (very hard) was used for exercise intensity guidance in the initial four exercise sessions that took place before a cardiopulmonary exercise test, as in usual care rehabilitation. The heart rate was recorded and blinded to the participants. After performing the test, the participants were then instructed using heart rate monitors openly for exercise guidance in four subsequent exercise sessions, at an intensity corresponding to 85-95% of peak heart rate. RESULTS: The mean exercise intensity during high-intensity bouts was 82% (6%) of peak heart rate for the rating of perceived exertion and 85% (6%) using heart rate monitors (p=0.005). Bland-Altman limits of agreement analysis with a mean bias showed a bias of 2.97 (-2.08, 8.02) percentage points for the two methods. Exercise intensity was highly repeatable with intra-class correlations of 0.95 (95% CI 0.86-0.99, p<0.001) and 0.96 (95% CI 0.88-0.99, p<0.001) in the exercise sessions using rating of perceived exertion and percentage of peak heart rate for intensity control, respectively. CONCLUSIONS: Rating of perceived exertion results in an exercise intensity below target during high-intensity interval training bouts in cardiac rehabilitation. Heart rate monitoring should be used for accurate intensity guidance.

Aamot IL; Forbord SH; Karlsen T; Støylen A

2013-08-01

283

Heart rate control in patients with chronic atrial fibrillation and heart failure.  

UK PubMed Central (United Kingdom)

The goal of this study was to determine whether aggressive heart rate (HR) control in patients with both chronic atrial fibrillation (AF) and heart failure (HF) is associated with improved outcomes. HR control is one of the mainstays in management of patients with AF. However, rate control can be challenging in patients with HF. This study was designed as an interventional clinical trial, using patients with chronic AF and left ventricular systolic dysfunction with left ventricular ejection fraction ?40% (n=20) as their own controls. Intervention consisted of increasing doses of metoprolol succinate to achieve target resting HR <70 beats per minute. Clinical data were collected at baseline and after intervention, with paired t test used to evaluate statistically significant change. After 3 months of intervention, average resting HR decreased from 94±14 beats per minute to 85±12 beats per minute. Average metoprolol succinate dose at the end of the study was 121 mg. None of the outcomes improved significantly after the intervention, including exercise tolerance (meters walked on 6-minute walk test 326±83 vs 330±86), quality of life (Minnesota Living With Heart Failure Questionnaire score of 42.5±19 vs 38±21), and brain natriuretic peptide (242±306 pg/mL vs 279±395 pg/mL). Aggressive HR control was difficult in this group of patients with chronic AF and HF due to patient intolerance of increasing doses of ?-blockade, and not associated with improved outcomes. Further studies are needed to establish guidelines for target HR in patients with chronic AF who also have significant HF.

Silvet H; Hawkins LA; Jacobson AK

2013-01-01

284

Joint symbolic analyses of heart rate, blood pressure and respiratory dynamics.  

UK PubMed Central (United Kingdom)

INTRODUCTION: The dynamics of cardiovascular variables are modulated by respiration. The aim of this study was to assess baroreflex function in normal subjects based on the joint symbolic dynamics of heart rate, blood pressure and respiration. METHODS: ECG, continuous blood pressure and respiration were recorded in ten healthy subjects during rest in the supine position and upon standing. Beat-to-beat time series of heart rate, systolic blood pressure and respiratory phase were extracted and transformed into binary symbol sequences. Words of length two that were reflective of baroreflex activity were statistically analysed with respect to the respiratory phase. RESULTS: Symbolic analysis showed a significant influence of the respiratory phase on the occurrence of baroreflex patterns. Upon standing, the frequency of baroreflex words increased and the effect of respiration appeared to be reduced. CONCLUSIONS: Symbolic dynamics provide a simple representation of cardiovascular dynamics and may be useful for assessing baroreflex function.

Baumert M; Javorka M; Kabir MM

2013-08-01

285

Heart rate variability during a continuous performance test in children with problems of attention.  

UK PubMed Central (United Kingdom)

BACKGROUND: Children with impulsive behavior and poor self regulation have been shown to have low parasympathetic tone. High vagal tone is associated with attention to novel stimuli. OBJECTIVE: To study if Heart Rate Variability, an index of vagal tone, is a mediator of attention. METHOD: 77 children who performed a Continuous Performance test (TOVA test) had their EKG recorded for Heart Rate Variability Measurements. Subjects were assigned to groups according to their performance on the TOVA test and a general linear model for repeated measures applied. Pearson Correlations were applied for TOVA scores and HRV Values at four epochs. RESULTS: No individual correlations were found between Attention Scores and HRV. However, there was a significant group difference showing that good performers had a higher "vagal" tone than poor performers. CONCLUSION: The parasympathetic system as measured through HRV is not a mediator of attention. HRV may be an indicator of better health and ability to self regulate.

Eisenberg J; Richman R

2011-01-01

286

Heart rate recovery and heart rate variability are unchanged in patients with coronary artery disease following 12 weeks of high-intensity interval and moderate-intensity endurance exercise training.  

UK PubMed Central (United Kingdom)

Decreased heart rate variability and attenuated heart rate recovery following exercise are associated with an increased risk of mortality in cardiac patients. This study investigated the effects of 12 weeks of moderate-intensity endurance exercise (END) and a novel low-volume high-intensity interval exercise protocol (HIT) on measures of heart rate recovery and heart rate variability in patients with coronary artery disease (CAD). Fourteen males with CAD participated in 12 weeks of END or HIT training, each consisting of 2 supervised exercise sessions per week. END consisted of 30-50 min of continuous cycling at 60% peak power output (PPO). HIT involved ten 1-min intervals at 88% PPO separated by 1-min intervals at 10% PPO. Heart rate recovery at 1 min and 2 min was measured before and after training (pre- and post-training, respectively) using a submaximal exercise bout. Resting time and spectral and nonlinear domain measures of heart rate variability were calculated. Following 12 weeks of END and HIT, there was no change in heart rate recovery at 1 min (END, 40 ± 12 beats·min(-1) vs. 37 ± 19 beats·min(-1); HIT, 31 ± 8 beats·min(-1) vs. 35 ± 8 beats·min(-1); p ? 0.05 for pre- vs. post-training) or 2 min (END, 44 ± 18 beats·min(-1) vs. 43 ± 19 beats·min(-1); HIT, 42 ± 10 beats·min(-1) vs. 50 ± 6 beats·min(-1); p ? 0.05 for pre- vs. post-training). All heart rate variability indices were unchanged following END and HIT training. In conclusion, neither END nor HIT exercise programs elicited training-induced improvements in cardiac autonomic function in patients with CAD. The absence of improvements with training may be attributed to the optimal medical management and normative pretraining state of our sample.

Currie KD; Rosen LM; Millar PJ; McKelvie RS; Macdonald MJ

2013-06-01

287

Sleeping and resting respiratory rates in dogs with subclinical heart disease.  

Science.gov (United States)

Objective-To characterize sleeping respiratory rates (SRRs) and resting respiratory rates (RRRs), collected in the home environment, of dogs with subclinical heart disease that could result in left-sided congestive heart failure. Design-Prospective cross-sectional study. Animals-190 adult dogs with subclinical left-sided heart disease. Procedures-Most dogs had mitral valve disease or dilated cardiomyopathy of various severities. Clients collected ten 1-minute SRRs or RRRs during a period ranging from 1 week to 6 months. Clinicians provided echocardiographic and medical data on each patient. Results-The within-dog mean SRR (SRRmean; 16 breaths/min) was significantly lower than the within-dog mean RRR (RRRmean; 21 breaths/min). Seven dogs had SRRmean and 33 dogs had RRRmean > 25 breaths/min; 1 dog had SRRmean and 12 dogs had RRRmean > 30 breaths/min; these dogs mostly had a left atrial (LA)-to-aortic ratio > 1.8. Dogs with moderate LA enlargement had a significantly higher SRRmean than did other dogs. However, median SRRmean for each of 4 levels of LA enlargement was dog SRR and RRR remained stable for 10 consecutive measurements. Treatment with cardiac medications or presence of pulmonary hypertension was not associated with SRRmean or RRRmean. Conclusions and Clinical Relevance-Results suggested that dogs with confirmed subclinical left-sided heart disease of various severities generally had SRRmean dog SRRmean or RRRmean. (J Am Vet Med Assoc 2013;243:839-843). PMID:24004231

Ohad, Dan G; Rishniw, Mark; Ljungvall, Ingrid; Porciello, Francesco; Häggström, Jens

2013-09-15

288

Complex character analysis of heart rate variability following brain asphyxia.  

UK PubMed Central (United Kingdom)

In the present study Renyi entropy and L-Z complexity were used to characterize heart rate variability (HRV) of rats that were suffered from brain asphyxia and ischemia. Two groups of rats were studied: (a) rats (n=5) injected with NAALADase inhibitor, 2-PMPA, which has been proven neuroprotective in asphyxia injury and (b) control subjects (n=5) without medication. Renyi entropy and L-Z complexity of the R-R intervals (RRI) at different experiment stages were investigated in the two groups. The results show that both measures indicate less injury and better recovery in the drug injection group. The dynamic change of 90 min RRI signal after the asphyxia was investigated. The sudden reduction of the two parameters shows their sensitivity to the asphyxia insult.

Cai Y; Qiu Y; Wei L; Zhang W; Hu S; Smith PR; Crabtree VP; Tong S; Thakor NV; Zhu Y

2006-05-01

289

Spectral and Time Based Assessment of Meditative Heart Rate Signals  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this article was to study the effects of Chi meditation on heart rate variability (HRV). For this purpose, the statistical and spectral measures of HRV from the RR intervals were analyzed. In addition, it is concerned with finding adequate Auto-Regressive Moving Average (ARMA) model orders for spectral analysis of the time series formed from RR intervals. Therefore, Akaike’s Final Prediction Error (FPE) was taken as the base for choosing the model order. The results showed that overall the model order chosen most frequently for FPE was p = 8 for before meditation and p = 5 for during meditation. The results suggested that variety of orders in HRV models upon different psychological states could be due to some differences in intrinsic properties of the system.

Ateke Goshvarpour; Mousa Shamsi; Atefeh Goshvarpour

2013-01-01

290

[Continuous wavelet analysis of heart rate variability during general anesthesia].  

UK PubMed Central (United Kingdom)

The depth of anesthesia can be assessed by means of analyzing heart rate variability (HRV). Continuous wavelet transform (CWT) was used to obtain more accurate results on the changes of low frequency (LF) and high frequency (HF) components of HRV signals (RR interval sequences) before and after general anesthesia. With wavelet scale transformed into frequency, the obtained time-frequency energy distributions showed that the LF and HF components of HRV signals were suppressed after general anesthesia, while the LF/HF ratio reduced from 9.0219 to 3.5573. The time-frequency distribution showed that CWT can more accurately locate the abrupt changes in time-domain, giving more precise range of frequency changing, compared with traditional time-frequency analysis method. The results indicated that, as a new time-frequency analysis method of analyzing HRV during general anesthesia, CWT provides more accurate time-frequency location, and consequently, offers more accurate monitoring results of anesthesia depth.

Wang Y; Li C

2012-04-01

291

Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots  

International Nuclear Information System (INIS)

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.

2010-10-25

292

Design of an FECG scalp electrode fetal heart rate monitor.  

UK PubMed Central (United Kingdom)

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.

Reguig FB; Kirk DL

1996-03-01

293

Design of an FECG scalp electrode fetal heart rate monitor.  

Science.gov (United States)

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. PMID:8673321

Reguig, F B; Kirk, D L

1996-03-01

294

Heart rate variability and motion sickness during forklift simulator driving.  

UK PubMed Central (United Kingdom)

The goal of the study was to determine the effect of a 1-h hour long forklift truck virtual simulator driving on the mechanism of autonomic heart rate (HR) regulation in operators. The participants were divided into 2 subgroups: subjects with no definite inclination to motion sickness (group A) and subjects with a definite inclination to motion sickness (group B). Holter monitoring of electrocardiogram (ECG) signal was carried out in all subjects during the virtual simulator driving. For 12 consecutive epochs of ECG signal, HR variability analysis was conducted in time and frequency domains. In subjects with a definite inclination to motion sickness after ~30 min of the driving, changes in parameter values were found indicating an increase in sympathetic and parasympathetic activity with parasympathetic dominance.

Zu?ewicz K; Saulewicz A; Konarska M; Kaczorowski Z

2011-01-01

295

Heart rate variability exhibits complication-dependent changes postsurgery.  

UK PubMed Central (United Kingdom)

"Surgical stress response" is tissue damage postsurgery, leading to a systemic response (inflammation, sympathetic upregulation, and release of vasoactive chemicals), which is typically measured by C-reactive protein (CRP). We assessed arterial stiffness and heart rate variability (HRV)-additional parameters reflecting autonomic and vascular functions-in this response and their potential associations with postoperative complications. In 47 participants undergoing abdominal surgery, CRP, arterial stiffness, and HRV were measured pre- and postoperatively (days 1 and 2). C-reactive protein was significantly higher postoperatively in participants experiencing complications but not preoperatively. Compared to participants without complications, those with complications had increased HRV and pnn50 (time domain) and tendency toward increasing low-frequency/high-frequency ratio (frequency domain) on postoperative day 2. Therefore, time and frequency domain HRV parameters show perioperative changes in relation to complication development. These findings suggest the applicability of this noninvasive technology to a variety of abdominal operations. Larger studies need to confirm these findings.

Scheffler P; Muccio S; Egiziano G; Doonan RJ; Yu A; Carli F; Daskalopoulou SS

2013-11-01

296

A subtle threat cue, heart rate variability, and cognitive performance.  

UK PubMed Central (United Kingdom)

This research was designed to extend the literature on heart rate variability (HRV) in cognitive performance contexts by examining whether a subtle threat cue (the color red) in a test environment influences HRV reactivity and whether HRV reactivity is associated with change in cognitive performance. Thirty-three participants took an IQ test, briefly viewed red or a chromatic or achromatic control color, and then took a parallel form of the IQ test. High frequency (HF)-HRV (often referred to as respiratory sinus arrhythmia), was assessed before and after the color manipulation. Results indicated that participants who viewed red (relative to a control color) exhibited a decrease in HF-HRV and that decreased HF-HRV was associated with worse IQ performance. These findings demonstrate the sensitivity of HRV as an index of effective and efficient emotion regulation in an achievement context.

Elliot AJ; Payen V; Brisswalter J; Cury F; Thayer JF

2011-10-01

297

Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients  

CERN Multimedia

In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtain a time-frequency representation of the signal, which provides better insight in the frequency distribution of the signal with time. A 6 level decomposition of HRV was achieved with db4 as mother wavelet, and the above two bands LF and HF were combined in 12 specialized frequencies sub-bands obtained in wavelet package transform. Features extracted from these coefficients can efficiently represent the characteristics of the original signal. ANOVA statistical test is used for the evaluation of proposed algorithm.

Kheder, G; Massoued, M Ben; Samet, M

2009-01-01

298

Relationship Between Maternal Distress with Fetus Growth Rate: Mediator Role of Heart Rate  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of present investigation was to study the relationship between mothers` distress and fetal growth. In this correlational study, 110 pregnant women selected randomly and completed Depression Anxiety Stress Scale (DASS) before ultrasound measurement of fetus. The results of structural equation model have shown that the overall model has been accepted (?2 = 36.4, df = 24, p>0.05). In fact, by increasing mothers` stress and anxiety, the fetus heart rate was increased and it decreased the height, weight, head circumference and width and femur length of fetus. Therefore, one of the environmental variables that have negative effect on the fetus growth is mother distress, because it can stimulate the fetal autonomic nervous system through the mediating of heart rate.

M. Shafizadeh; M. Mehdizadeh

2009-01-01

299

The prognostic significance of heart rate recovery is not dependent upon maximal effort in patients with heart failure.  

UK PubMed Central (United Kingdom)

BACKGROUND: Heart rate recovery (HRR) has been observed to be a significant prognostic measure in patients with heart failure (HF). However, the prognostic value of HRR has not been examined in regard to the level of patient effort during exercise testing. Using the peak respiratory exchange ratio (RER) and a large multicenter HF database we examined the prognostic utility of HRR. METHODS: Cardiopulmonary exercise testing (CPX) was performed in 806 HF patients who then underwent an active cool-down of at least 1min. Peak oxygen consumption (VO(2)), ventilatory efficiency (VE/VCO(2) slope), and peak RER were determined with subjects categorized into subgroups according to peak RER (<1.00, 1.00-1.09, ?1.10). HRR was defined as the difference between heart rate at peak exercise and 1min following test termination. Patients were followed for major cardiac events for up to four years post-CPX. RESULTS: There were 163 major cardiac events (115 deaths, 20 left ventricular assist device implantations, and 28 transplantations) during the four year tracking period. Univariate Cox regression analysis results identified HRR as a significant (p<0.05) univariate predictor of adverse events regardless of the RER achieved. Multivariate Cox regression analysis in the overall group revealed that the VE/VCO(2) slope was the strongest predictor of adverse events (chi-square: 110.9, p<0.001) with both HRR (residual chi-square: 16.7, p<0.001) and peak VO(2) (residual chi-square: 10.4, p<0.01) adding significant prognostic value. CONCLUSIONS: HRR after symptom-limited exercise testing performed at sub-maximal efforts using RER to categorize level of effort is as predictive as HRR after maximal effort in HF patients.

Cahalin LP; Forman DE; Chase P; Guazzi M; Myers J; Bensimhon D; Peberdy MA; Ashley E; West E; Arena R

2013-02-01

300

The benefits of ivabradine are independent of resting heart rate.  

Science.gov (United States)

Evaluation of: Tardif JC, Ponikowski P, Kahan T; on behalf of the ASSOCIATE investigators. Effects of ivabradine in patients with stable angina receiving beta-blockers according to baseline heart rate: an analysis of the ASSOCIATE study. Int. J. Cardiol. pii:S0167-5273(12)01385-X (2012). Chronic stable angina pectoris is the most common manifestation of coronary artery disease. A large body of evidence points to high resting heart rate (HR) as a risk factor for mortality in various populations, including patients with cardiovascular disease. Elevated HR is an important pathophysiological variable that increases myocardial oxygen demand and also limits tissue perfusion by reducing the duration of diastole, during which most myocardial perfusion occurs. Large epidemiological trials have established that elevated resting HR is a prognostic factor for cardiovascular events and mortality in healthy individuals and in patients with myocardial infarction, stable coronary artery disease and heart failure. The classical treatments for HR reduction show such negative aspects. ?-blocker therapy exerts negative effects on regional myocardial blood flow and function when HR reduction is eliminated by atrial pacing. Calcium channel antagonists functionally antagonize coronary vasoconstriction mediated through ?-adrenoreceptors and are thus devoid of this undesired effect, but the compounds are nevertheless negative inotrope. Ivabradine (IVA), a pure HR-lowering drug, reduces the myocardial oxygen demand of exercise and contributes to the restoration of oxygen balance, which has demonstrated a benefit in chronic cardiovascular disease. No relevant negative effects are evidenced on cardiac conduction, contractility, relaxation or repolarization, or blood pressure. In this post-hoc analysis, the authors show that IVA treatment, compared with the placebo group, had no significant impact on systolic or diastolic blood pressure at rest or during exercise and reduces HR in all stages of physical exercise and during the treatment period. These benefits are independent of baseline HR, both at rest and during physical exercise, confirming that HR reduction with IVA is beneficial in all patients, even with ?-blocker therapy, if their resting HR is above 60 bpm. PMID:23668736

Riccioni, Graziano

2013-05-01

 
 
 
 
301

The benefits of ivabradine are independent of resting heart rate.  

UK PubMed Central (United Kingdom)

Evaluation of: Tardif JC, Ponikowski P, Kahan T; on behalf of the ASSOCIATE investigators. Effects of ivabradine in patients with stable angina receiving beta-blockers according to baseline heart rate: an analysis of the ASSOCIATE study. Int. J. Cardiol. pii:S0167-5273(12)01385-X (2012). Chronic stable angina pectoris is the most common manifestation of coronary artery disease. A large body of evidence points to high resting heart rate (HR) as a risk factor for mortality in various populations, including patients with cardiovascular disease. Elevated HR is an important pathophysiological variable that increases myocardial oxygen demand and also limits tissue perfusion by reducing the duration of diastole, during which most myocardial perfusion occurs. Large epidemiological trials have established that elevated resting HR is a prognostic factor for cardiovascular events and mortality in healthy individuals and in patients with myocardial infarction, stable coronary artery disease and heart failure. The classical treatments for HR reduction show such negative aspects. ?-blocker therapy exerts negative effects on regional myocardial blood flow and function when HR reduction is eliminated by atrial pacing. Calcium channel antagonists functionally antagonize coronary vasoconstriction mediated through ?-adrenoreceptors and are thus devoid of this undesired effect, but the compounds are nevertheless negative inotrope. Ivabradine (IVA), a pure HR-lowering drug, reduces the myocardial oxygen demand of exercise and contributes to the restoration of oxygen balance, which has demonstrated a benefit in chronic cardiovascular disease. No relevant negative effects are evidenced on cardiac conduction, contractility, relaxation or repolarization, or blood pressure. In this post-hoc analysis, the authors show that IVA treatment, compared with the placebo group, had no significant impact on systolic or diastolic blood pressure at rest or during exercise and reduces HR in all stages of physical exercise and during the treatment period. These benefits are independent of baseline HR, both at rest and during physical exercise, confirming that HR reduction with IVA is beneficial in all patients, even with ?-blocker therapy, if their resting HR is above 60 bpm.

Riccioni G

2013-05-01

302

Heart rate response to hypoxic exercise : role of dopamine D2-receptors and effect of oxygen supplementation  

DEFF Research Database (Denmark)

This study examined the effects of dopamine D(2)-receptor blockade on the early decrease in maximal heart rate at high altitude (4559 m). We also attempted to clarify the time-dependent component of this reduction and the extent to which it is reversed by oxygen breathing. Twelve subjects performed two consecutive maximal exercise tests, without and with oxygen supplementation respectively, at sea level and after 1, 3 and 5 days at altitude. On each study day, domperidone (30 mg; n=6) or no medication (n=6) was given 1 h before the first exercise session. Compared with sea level, hypoxia progressively decreased the maximal heart rate from day 1 and onwards; also, hypoxia by itself increased plasma noradrenaline levels after maximal exercise. Domperidone further increased maximal noradrenaline concentrations, but had no effect on maximal heart rate. On each study day at altitude, oxygen breathing completely reversed the decrease in maximal heart rate to values not different from those at sea level. In conclusion, dopamine D(2)-receptor blockade with domperidone demonstrates that hypoxic exercise in humans activates D(2)-receptors, resulting in a decrease in circulating levels of noradrenaline. However, dopamine D(2)-receptors are not involved in the hypoxia-induced decrease in the maximal heart rate. These data suggest that receptor uncoupling, and not down-regulation, of cardiac adrenoreceptors, is responsible for the early decrease in heart rate at maximal hypoxic exercise.

Lundby, C; MØller, P

2001-01-01

303

Role of GABAA receptors of bed nucleus stria terminalis in controlling of blood pressure and heart rate in rats  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: The Bed nucleus stria terminalis (BST) is a part of the limbic system. It was recently shown that chemical stimulation of the BST by L-glutamate elicited cardiovascular depressive responses. In the present study, we have investigated the possible cardiovascular role of the GABAergic receptors in BST by microinjection of its agonist and antagonists. Methods: Experiments were performed on 21 anaesthetized rats. Drugs were microinjected into the BST in volume of 50 nl using streotaxic apparatus. Blood pressure and heart rate were recorded before and throughout each experiment. The averages of maximum changes in the arterial pressure and heart rate were compared with control group and with its average in before injections using student t-test and paired t-test, respectively. Results: GABAA receptor antagonist, bicuculline met iodide (BMI, 1 mM), increased both arterial pressure (+14.2±3.08) and heart rate (+9.8± 2.5) (p<0.05). Muscimole, a GABAA agonist (5 mM), caused a significant decrease of the arterial pressure (-10.2 ±4.1) and heart rate (-20.3±9.40) (p<0.01). However, microinjection of phaclofen (5 mM), a GABAB receptor antagonist caused small unsignificant changes of the heart rate and blood pressure. Conclusion: GABAergic inhibitory neurons of the BST seems to cause decrease in the blood pressure and heart rate by GABAA but not GABAB receptors.

Maesoumeh Hatam; Ali Nasimi

2007-01-01

304

Safety and efficacy of oral ivabradine as a heart rate-reducing agent in patients undergoing CT coronary angiography.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate the role of oral ivabradine as a heart rate reducing agent in patients undergoing CT coronary angiography (CTCA). Despite the routine use of ?-blockers prior to CTCA studies, it is not uncommon to have patients with heart rates persistently above the target range of 65 bpm. Ivabradine is a selective inhibitor of the I(f) current, which primarily contributes to sinus node pacemaker activity, and has no significant direct cardiovascular effects such as reduction of blood pressure, cardiac contractility or impairment of cardiac conduction. METHODS: We investigated 100 consecutive patients who had been referred for CTCA for the evaluation of suspected coronary artery disease (CAD). Patients were randomised to receive either of the following two pre-medication protocols: oral metorprolol or oral ivabradine. RESULTS: Ivabradine was significantly more effective than metorprolol in lowering the heart rate; the mean percentage reduction in heart rate with ivabradine vs metorpolol was 23.89+6.95% vs 15.20+4.50%, respectively (p=0.0001). Metoprolol significantly lowered both systolic and diastolic blood pressure while ivabradine did not. The requirement of additional doses to achieve a target heart rate of <65 beats per min was also significantly more frequent with metoprolol. CONCLUSION: Ivabradine is a potentially attractive alternative to currently used drugs for reduction of heart rate in patients undergoing CTCA.

Adile KK; Kapoor A; Jain SK; Gupta A; Kumar S; Tewari S; Garg N; Goel PK

2012-08-01

305

Resonance of about-weekly human heart rate rhythm with solar activity change.  

UK PubMed Central (United Kingdom)

In several human adults, certain solar activity rhythms may influence an about 7-day rhythm in heart rate. When no about-weekly feature was found in the rate of change in sunspot area, a measure of solar activity, the double amplitude of a circadian heart rate rhythm, approximated by the fit of a 7-day cosine curve, was lower, as was heart rate corresponds to about-weekly features in solar activity and/or relates to a sunspot cycle.

Cornelissen G; Halberg F; Wendt HW; Bingham C; Sothern RB; Haus E; Kleitman E; Kleitman N; Revilla MA; Revilla M Jr; Breus TK; Pimenov K; Grigoriev AE; Mitish MD; Yatsyk GV; Syutkina EV

1996-12-01

306

Impact of heart rate and rhythm on radiation exposure in prospectively ECG triggered computed tomography.  

UK PubMed Central (United Kingdom)

PURPOSE: To evaluate the influence of different heart rates and arrhythmias on scanner performance, image acquisition and applied radiation exposure in prospectively ECG triggered computed tomography (pCT). MATERIALS AND METHODS: An ECG simulator (EKG Phantom 320, Müller & Sebastiani Elektronik GmbH, Munich, Germany) was used to generate different heart rhythms and arrhythmias: sinus rhythm (SR) at 45, 60, 75, 90 and 120/min, supraventricular arrhythmias (e.g. sinus arrhythmia, atrial fibrillation) and ventricular arrhythmias (e.g. ventricular extrasystoles), pacemaker-ECGs, ST-changes and technical artifacts. The analysis of the image acquisition process was performed on a 64-row multidetector CT (Brilliance, Philips Medical Systems, Cleveland, USA). A prospectively triggered scan protocol as used for routine was applied (120 kV; 150 mAs; 0.4s rotation and exposure time per scan; image acquisition predominantly in end-diastole at 75% R-R-interval, in arrythmias with a mean heart rate above 80/min in systole at 45% of the R-R-interval; FOV 25 cm). The mean dose length product (DLP) and its percentage increase from baseline (SR at 60/min) were determined. RESULT: Radiation exposure can increase significantly when the heart rhythm deviates from sinus rhythm. ECG-changes leading to a significant DLP increase (p<0.05) were bifocal pacemaker (61%), pacemaker dysfunction (22%), SVES (20%), ventricular salvo (20%), and atrial fibrillation (14%). Significantly (p<0.05) prolonged scan time (>8 s) could be observed in bifocal pacemaker (12.8 s), pacemaker dysfunction (10.7 s), atrial fibrillation (10.3 s) and sinus arrhythmia (9.3 s). CONCLUSION: In prospectively ECG triggered CT, heart rate and rhythm can provoke different types of scanner performance, which can significantly alter radiation exposure and scan time. These results might have an important implication for indication, informed consent and contrast agent injection protocols.

Luecke C; Andres C; Foldyna B; Nagel HD; Hoffmann J; Grothoff M; Nitzsche S; Gutberlet M; Lehmkuhl L

2012-09-01

307

Early Ventilation-Heart Rate Breakpoint during Incremental Cycling Exercise.  

UK PubMed Central (United Kingdom)

Previous observations having reported a transient hypoxia at the onset of incremental exercise, we investigated the existence of concomitant ventilatory and heart rate (HR) breakpoints.33 subjects executed a maximal cycling exercise with averaging for successive 5-s periods of HR, ventilation, tidal volume (VT), mean inspiratory flow rate (VT/Ti), and end-tidal partial pressures of O2 (PETO2) and CO2. In 10 subjects, the transcutaneous partial pressure of O2 (PtcO2) was recorded and the venous blood lactic acid (LA) concentration measured.At the beginning of exercise, PETO2 decreased, reaching a nadir, then progressively increased until the exercise ended. PtcO2 varied in parallel. Whether or not a 0-W cycling period preceded the incremental exercise, the rate of changes in VE, VT, VT/Ti and HR significantly increased when the nadir PO2 was reached. The ventilatory/ HR breakpoint was measured at 33±4% of VO2max, whereas the ventilatory threshold (VTh) was detected at 67±4% of VO2max and LA began to increase at 45 to 50% of VO2max.During incremental cycling exercise, we identified the existence of HR and ventilatory breakpoints in advance of both lactate and ventilatory thresholds which coincided with modest hypoxia and hypercapnia.

Gravier G; Delliaux S; Ba A; Delpierre S; Guieu R; Jammes Y

2013-08-01

308

Cortisol release, heart rate and heart rate variability in the horse and its rider: different responses to training and performance.  

UK PubMed Central (United Kingdom)

Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n=6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (P<0.001) but did not differ between performance and rehearsal. HR in horses and riders increased during the rehearsal and the public performance (P<0.001) but the increase in HR was more pronounced (P<0.01) in riders than in their horses during the public performance (from 91 ± 10 to 150 ± 15 beats/min) compared to the rehearsal (from 94 ± 10 to 118 ± 12 beats/min). The SDRR decreased significantly during the equestrian tasks in riders (P<0.001), but not in their horses. The RMSSD decreased in horses and riders (P<0.001) during rehearsal and performance, indicating a decrease in parasympathetic tone. The decrease in RMSSD in the riders was more pronounced (P<0.05) during the performance (from 32.6 ± 6.6 to 3.8 ± 0.3 ms) than during the rehearsal (from 27.5 ± 4.2 to 6.6 ± 0.6 ms). The study has shown that the presence of spectators caused more pronounced changes in cardiac activity in the riders than it did in their horses.

von Lewinski M; Biau S; Erber R; Ille N; Aurich J; Faure JM; Möstl E; Aurich C

2013-08-01

309

Cortisol release, heart rate and heart rate variability in the horse and its rider: Different responses to training and performance.  

Science.gov (United States)

Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n=6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (P<0.001) but did not differ between performance and rehearsal. HR in horses and riders increased during the rehearsal and the public performance (P<0.001) but the increase in HR was more pronounced (P<0.01) in riders than in their horses during the public performance (from 91±10 to 150±15beats/min) compared to the rehearsal (from 94±10 to 118±12beats/min). The SDRR decreased significantly during the equestrian tasks in riders (P<0.001), but not in their horses. The RMSSD decreased in horses and riders (P<0.001) during rehearsal and performance, indicating a decrease in parasympathetic tone. The decrease in RMSSD in the riders was more pronounced (P<0.05) during the performance (from 32.6±6.6 to 3.8±0.3ms) than during the rehearsal (from 27.5±4.2 to 6.6±0.6ms). The study has shown that the presence of spectators caused more pronounced changes in cardiac activity in the riders than it did in their horses. PMID:23380228

von Lewinski, Mareike; Biau, Sophie; Erber, Regina; Ille, Natascha; Aurich, Jörg; Faure, Jean-Michel; Möstl, Erich; Aurich, Christine

2013-02-04

310

Docosahexaenoic acid-rich fish oil improves heart rate variability and heart rate responses to exercise in overweight adults.  

Science.gov (United States)

Dietary fish oil supplementation and regular physical activity can improve outcomes in patients with established CVD. Exercise has been shown to improve heart rate variability (HRV), a predictor of cardiac death, but whether fish oil benefits HRV is controversial. Obese adults at risk of future coronary disease have impaired HRV and may benefit from these interventions. We evaluated the effect of DHA-rich tuna fish oil supplementation with and without regular exercise on HRV in sedentary, overweight adults with risk factors for coronary disease. In a randomised, double-blind, parallel comparison, sixty-five volunteers consumed 6 g fish oil/d (DHA 1.56 g/d, EPA 0.36 g/d) or sunflower-seed oil (placebo) for 12 weeks. Half of each oil group also undertook regular moderate physical activity (3 d/week for 45 min, at 75 % of age-predicted maximal heart rate (HR)). Resting HR and the HR response to submaximal exercise were measured at weeks 0, 6 and 12. In forty-six subjects, HRV was also assessed by power spectrum analysis of 20 min electrocardiogram recordings taken supine at baseline and 12 weeks. Fish oil supplementation improved HRV by increasing high-frequency power, representing parasympathetic activity, compared with placebo (P = 0.01; oil x time interaction). It also reduced HR at rest and during submaximal exercise (P = 0.008; oil x time interaction). There were no significant fish oil x exercise interactions. Dietary supplementation with DHA-rich fish oil reduced HR and modulated HRV in keeping with an improved parasympathetic-sympathetic balance in overweight adults with risk factors for future coronary disease. PMID:18339222

Ninio, Daniel M; Hill, Alison M; Howe, Peter R; Buckley, Jonathan D; Saint, David A

2008-03-13

311

Skeletal muscle signaling and the heart rate and blood pressure response to exercise : insight from heart rate pacing during exercise with a trained and a deconditioned muscle group  

DEFF Research Database (Denmark)

Endurance training lowers heart rate and blood pressure responses to exercise, but the mechanisms and consequences remain unclear. To determine the role of skeletal muscle for the cardioventilatory response to exercise, 8 healthy young men were studied before and after 5 weeks of 1-legged knee-extensor training and 2 weeks of deconditioning of the other leg (leg cast). Hemodynamics and muscle interstitial nucleotides were determined during exercise with the (1) deconditioned leg, (2) trained leg, and (3) trained leg with atrial pacing to the heart rate obtained with the deconditioned leg. Heart rate was ˜15 bpm lower during exercise with the trained leg (P

Mortensen, Stefan Peter; Svendsen, Jesper H

2013-01-01

312

Heart rate and stroke volume response patterns to augmented orthostatic stress.  

UK PubMed Central (United Kingdom)

AIMS: Combined head up tilt (HUT) and lower body negative pressure (LBNP) can be used to exploit the full spectrum of cardiovascular control mechanisms and to reveal characteristics of individual blood pressure control. We studied whether the response to combined HUT and LBNP was reproducible within subjects and whether characteristic response patterns could be distinguished between different subjects. MATERIALS AND METHODS: Ten healthy young males were subjected to combined HUT and graded LBNP to achieve a presyncopal end point in four tests, each separated by more than 2 weeks. Heart rate, blood pressure and thoracic impedance were monitored, cardiac output and peripheral vascular resistance were computed. RESULTS: From supine control to presyncope, heart rate, mean arterial blood pressure, pulse pressure and stroke index changed as expected. The time courses of heart rate and stroke volume as well as orthostatic tolerance times (15 +/- 6 to 18 +/- 7 minutes, n.s) appeared reproducible between trials within subjects but different between different subjects. CONCLUSION: LBNP-tilt approach was repeatable in time and pattern. Furthermore, differences observed between subjects indicated preferred activation of selected pathways of blood pressure control in different individuals while at the same time, reproducibility measured within the same subject showed that preferential mechanisms were highly conserved within the same individual. These characteristics are a prerequisite to use the combined graded orthostatic paradigm for hemodynamic testing and identification.

Goswami N; Roessler A; Lackner HK; Schneditz D; Grasser E; Hinghofer-Szalkay HG

2009-06-01

313

Heart rate reduction by ivabradine improves aortic compliance in apolipoprotein E-deficient mice.  

UK PubMed Central (United Kingdom)

BACKGROUND: Impaired vascular compliance is associated with cardiovascular mortality. The effects of heart rate on vascular compliance are unclear. Therefore, we characterized effects of heart rate reduction (HRR) by I(f) current inhibition on aortic compliance and underlying molecular mechanisms in apolipoprotein E-deficient (ApoE(-)/(-)) mice. METHODS: ApoE(-)/(-) mice fed a high-cholesterol diet and wild-type (WT) mice were treated with ivabradine (20 mg/kg/d) or vehicle for 6 weeks. Compliance of the ascending aorta was evaluated by MRI. RESULTS: Ivabradine reduced heart rate by 113 ± 31 bpm (~19%) in WT mice and by 133 ± 6 bpm (~23%) in ApoE(-)/(-) mice. Compared to WT controls, ApoE(-)/(-) mice exhibited reduced distensibility and circumferential strain. HRR by ivabradine increased distensibility and circumferential strain in ApoE(-)/(-) mice but did not affect both parameters in WT mice. Ivabradine reduced aortic protein and mRNA expression of the angiotensin II type 1 (AT1) receptor and reduced rac1-GTPase activity in ApoE(-)/(-) mice. Moreover, membrane translocation of p47(phox) was inhibited. In ApoE(-)/(-) mice, HRR induced anti-inflammatory effects by reduction of aortic mRNA expression of IL-6, TNF-alpha and TGF-beta. CONCLUSION: HRR by ivabradine improves vascular compliance in ApoE(-)/(-) mice. Contributing mechanisms include downregulation of the AT1 receptor, attenuation of oxidative stress and modulation of inflammatory cytokine expression.

Custodis F; Fries P; Müller A; Stamm C; Grube M; Kroemer HK; Böhm M; Laufs U

2012-01-01

314

Resting heart rate as a predictor of metabolic dysfunctions in obese children and adolescents.  

UK PubMed Central (United Kingdom)

BACKGROUND: Recent studies have identified that a higher resting heart rate (RHR) is associated with elevated blood pressure, independent of body fatness, age and ethnicity. However, it is still unclear whether RHR can also be applied as a screening for other risk factors, such as hyperglycemia and dyslipidemia. Thus, the purpose of the presented study was to analyze the association between RHR, lipid profile and fasting glucose in obese children and adolescents. METHODS: The sample was composed of 180 obese children and adolescents, aged between 7-16 years. Whole-body and segmental body composition were estimated by Dual-energy X-ray absorptiometry. Resting heart rate (RHR) was measured by heart rate monitors. The fasting blood samples were analyzed for serum triglycerides, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and glucose, using the colorimetric method. RESULTS: Fasting glucose, TC, triglycerides, HDL-C, LDL-C and RHR were similar in both genders. The group of obese subjects with a higher RHR presented, at a lower age, higher triglycerides and TC. There was a significant relationship between RHR, triglycerides and TC. In the multivariate model, triglycerides and TC maintained a significant relationship with RHR independent of age, gender, general and trunk adiposity. The ROC curve indicated that RHR has a high potential for screening elevated total cholesterol and triglycerides as well as dyslipidemia. CONCLUSION: Elevated RHR has the potential to identify subjects at an increased risk of atherosclerosis development.

Freitas Júnior IF; Monteiro PA; Silveira LS; Cayres SU; Antunes BM; Bastos KN; Codogno JS; Sabino JP; Fernandes RA

2012-01-01

315

Exercise heart rate monitors for anxiety treatment in a rural primary care setting: a pilot study.  

UK PubMed Central (United Kingdom)

BACKGROUND AND OBJECTIVES: Rural patients with anxiety often lack access to traditional biofeedback modalities. Exercise heart rate monitors (HRMs) are tools used in the fitness industry to provide athletes with feedback on heart rate and regulatory breathing strategies. HRMs are inexpensive, discrete, and publicly accessible. This randomized controlled pilot study explored whether use of HRMs for biofeedback during guided mindfulness, diaphragmatic breathing, and progressive muscle relaxation techniques could facilitate anxiety reduction as compared to these techniques alone. METHODS: Fifty-three rural anxiety patients were randomized to HRM or control groups for four weekly 20-minute, scripted sessions with a non-behaviorist wherein they practiced these techniques; the HRM group received feedback on their heart rate response. RESULTS: The HRM group had significantly greater improvement in state anxiety (State-Trait Anxiety Inventory) and self-efficacy (General Self Efficacy Scale), and a greater percentage of the group indicated that they "felt in control of their anxiety." CONCLUSIONS: This pilot study demonstrates that this novel, inexpensive, and accessible tool may be a useful clinical intervention for anxiety and can be easily incorporated by both behaviorists and non-behaviorist primary care clinicians into individual or group biofeedback treatment for patients with anxiety. This tool has additional potential for patients to use for anxiety self-management. Further study with a larger sample and blinded design is warranted.

Houser MM; Rosen L; Seagrave MP; Grabowski D; Matthew JD; Craig WA

2013-10-01

316

Heart rate variability analysis during central hypovolemia using wavelet transformation.  

UK PubMed Central (United Kingdom)

Detection of hypovolemia prior to overt hemodynamic decompensation remains an elusive goal in the treatment of critically injured patients in both civilian and combat settings. Monitoring of heart rate variability has been advocated as a potential means to monitor the rapid changes in the physiological state of hemorrhaging patients, with the most popular methods involving calculation of the R-R interval signal's power spectral density (PSD) or use of fractal dimensions (FD). However, the latter method poses technical challenges, while the former is best suited to stationary signals rather than the non-stationary R-R interval. Both approaches are also limited by high inter- and intra-individual variability, a serious issue when applying these indices to the clinical setting. We propose an approach which applies the discrete wavelet transform (DWT) to the R-R interval signal to extract information at both 500 and 125 Hz sampling rates. The utility of machine learning models based on these features were tested in assessing electrocardiogram signals from volunteers subjected to lower body negative pressure induced central hypovolemia as a surrogate of hemorrhage. These machine learning models based on DWT features were compared against those based on the traditional PSD and FD, at both sampling rates and their performance was evaluated based on leave-one-subject-out fold cross-validation. Results demonstrate that the proposed DWT-based model outperforms individual PSD and FD methods as well as the combination of these two traditional methods at both sample rates of 500 Hz (p value <0.0001) and 125 Hz (p value <0.0001) in detecting the degree of hypovolemia. These findings indicate the potential of the proposed DWT approach in monitoring the physiological changes caused by hemorrhage. The speed and relatively low computational costs in deriving these features may make it particularly suited for implementation in portable devices for remote monitoring.

Ji SY; Belle A; Ward KR; Ryan KL; Rickards CA; Convertino VA; Najarian K

2013-06-01

317

Heart rate variability analysis during central hypovolemia using wavelet transformation.  

Science.gov (United States)

Detection of hypovolemia prior to overt hemodynamic decompensation remains an elusive goal in the treatment of critically injured patients in both civilian and combat settings. Monitoring of heart rate variability has been advocated as a potential means to monitor the rapid changes in the physiological state of hemorrhaging patients, with the most popular methods involving calculation of the R-R interval signal's power spectral density (PSD) or use of fractal dimensions (FD). However, the latter method poses technical challenges, while the former is best suited to stationary signals rather than the non-stationary R-R interval. Both approaches are also limited by high inter- and intra-individual variability, a serious issue when applying these indices to the clinical setting. We propose an approach which applies the discrete wavelet transform (DWT) to the R-R interval signal to extract information at both 500 and 125 Hz sampling rates. The utility of machine learning models based on these features were tested in assessing electrocardiogram signals from volunteers subjected to lower body negative pressure induced central hypovolemia as a surrogate of hemorrhage. These machine learning models based on DWT features were compared against those based on the traditional PSD and FD, at both sampling rates and their performance was evaluated based on leave-one-subject-out fold cross-validation. Results demonstrate that the proposed DWT-based model outperforms individual PSD and FD methods as well as the combination of these two traditional methods at both sample rates of 500 Hz (p value DWT approach in monitoring the physiological changes caused by hemorrhage. The speed and relatively low computational costs in deriving these features may make it particularly suited for implementation in portable devices for remote monitoring. PMID:23371800

Ji, Soo-Yeon; Belle, Ashwin; Ward, Kevin R; Ryan, Kathy L; Rickards, Caroline A; Convertino, Victor A; Najarian, Kayvan

2013-02-01

318

Heart Rate Variability in Cavalier King Charles Spaniels with Different Degree of Myxomatous Mitral Valve Disease  

DEFF Research Database (Denmark)

Heart Rate Variability in Cavalier King Charles Spaniels with Different Degree of Myxomatous Mitral Valve Disease Rasmussen, C.E. 1, Falk, T. 1, Zois, N.E. 1, Moesgaard, S.G. 1, Häggström, J. 2, Pedersen, H.D. 3 and Olsen, L.H1. 1Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark, 2Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden; and 3Novo Nordic A/S, Maaloev, Denmark. Introduction: Modulation of heart rate by the autonomic nervous system can indirectly be measured by heart rate variability (HRV). Reduced HRV is seen in dogs with heart failure secondary to myxomatous mitral valve disease (MMVD). However, HRV is suggested to increase with disease progression in dogs with early stages of MMVD. Comparable results are found in people with primary mitral valve prolapse, a disease resembling canine MMVD. Aim: To associate progression of MMVD in dogs with time and frequency domain HRV, analysed from 24-hour electrocardiography. Materials and Methods: Eighty-one Cavalier King Charles Spaniels (CKCS) were examined by echocardiography and 24-hour electrocardiography. CKCS were divided into 4 groups: 1) no or minimal mitral regurgitation (MR) (MR jet=15% of the left atrial area) and no murmur, 2) mild MR (20%50%) and no clinical signs of heart failure, 4) left atrium to aortic root ratio >1.5, clinical signs of heart failure and furosemide responsiveness. Results: Ten out of 13 HRV variables decreased with increasing MMVD severity. In group 1, 10 HRV variables were increased compared to group 3 and 4 (P<0.05) and 2 HRV variables were increased compared to group 2 (P<0.04). Eight and 10 HRV variables were increased in group 2 compared to group 3 (P<0.01) and group 4 (P<0.001), respectively. Group 1 and 2 were younger than group 3 and 4 (P<0.0001). Only 2 HRV variables were influenced by age. Discussion and conclusion: Most HRV variables decreased with progression of MMVD in dogs; even prior to the development of overt congestive heart failure.

Rasmussen, Caroline Elisabeth; Falk, Bo Torkel

319

Blood pressure, heart rate and lipids in professional handball and water polo players  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Blood pressure, heart rate and lipoprotein lipids are affected by family history, obesity, diet, smoking and physical activity habits. The aim of this paper was to estimate the values of blood pressure and heart rate in professional handball and water polo players before and after training and submaximal exercise test and to analyze the lipid state in these professional athletes in comparison with people who have never been in sports. Material and methods The investigation included 30 professional handball players, 30 professional water polo players and 15 men who have never been in sports (control group). All groups were matched for age, smoking habits, family predisposition to arterial hypertension and dyslipidemia. Results Between these groups there were statistically significant differences of blood pressure values and heart rate in the state of rest, after exercise test and after the training. There were also statistically significant differences of total cholesterol values, LDL cholesterol, triglycerides, HDL cholesterol, LDL cholesterol/HDL cholesterol ratio and total cholesterol/HDL ratio between these groups. Discussion Differences between these groups can be explained by various values of body mass index, by activity of lipoprotein lipase in athletes, by body position during the sports activity, by thermoregulatory vasoconstriction in the water, and by effects of hydrostatic pressure and reflex mechanisms during swimming. Conclusions Cardiovascular reaction in professional athletes depends on the type of sports activity, body position and medium during training. Professional athletes have a lower atherogenic risk than non-sportsmen. Changes of blood pressure and heart rate after submaximal exercise test are not the same as changes after training. .

Jovanovi? Jovica; Jovanovi? Milan

2005-01-01

320

Cardiac resynchronization therapy: implant rates, temporal trends and relationships with heart failure epidemiology.  

UK PubMed Central (United Kingdom)

BACKGROUND: Consensus guidelines define indications for cardiac resynchronization therapy (CRT), but the variability in implant rates in 'real world' clinical practice, as well as the relationship with the epidemiology of heart failure are not defined. METHODS AND RESULTS: In Emilia-Romagna, an Italian region with around 4.4 million inhabitants, a registry was instituted to collect data on implanted devices for CRT, with (CRT-D) or without defibrillation (CRT-P) capabilities. Data from all consecutive patients resident in this region who underwent a first implant of a CRT device in years 2006-2010 were collected and standardized (considering each of the nine provinces of the region). The number of CRT implants increased progressively, with a 71% increase in 2010 compared to 2006. Between 84 and 90% of implants were with CRT-D devices. The variability in standardized implant rates among the provinces was substantial and the ratio between the provinces with the highest and the lowest implant rates was always greater than 2. Considering prevalent cases of heart failure in the period 2006-2010, the proportion of patients implanted with CRT per year ranged between 0.23 and 0.30%. CONCLUSIONS: The application in 'real world' clinical practice of CRT in heart failure is quite heterogeneous, with substantial variability even among areas belonging to the same region, with the need to make the access to this treatment more equitable. Despite the increased use of CRT, its overall rate of adoption is low, if a population of prevalent heart failure patients is selected on the basis of administrative data on hospitalizations.

Boriani G; Berti E; Belotti LM; Biffi M; Carboni A; Bandini A; Casali E; Tomasi C; Toselli T; Baraldi P; Bottoni N; Barbato G; Sassone B

2013-06-01

 
 
 
 
321

Effects of umbilical venous catheters on arrhythmia and heart rate variability in premature newborns  

Directory of Open Access Journals (Sweden)

Full Text Available Aim: Cardiac rhythm abnormalities associated with umbilical venous catheters in newborns are limited to anecdotal case reports. The present study intended to evaluate association between umbilical venous catheter, arrhythmic potential, and changes in heart rate variability.Material and Method: The study consisted of two groups; 26 preterm newborns with a umbilical venous catheter (group 1), and 26 control group without (group 2). The following parameters were recorded prospectively: gender, gestation at birth, birth weight, and clinical assessment scores (SNAP-II and SNAPPE-II). Holter recordings were fitted in all newborns. The heart rate variability study was performed by utilizing time-domain and frequency-domain analyses. Results: The study population consisted of group 1 (30.63±2.67 weeks of gestation) and group 2 (31.60±2.45 weeks of gestation). There was no statistical difference between the two groups for gestational age, birth weight, SNAP-II and SNAPPE- II scores. When compared for arrhythmia there was no statistical difference in any parameters between the two study groups. Premature atrial contraction was noted in 11 babies (42.3%) in group 1 and in 7 babies (26.9%) in group 2. Premature ventricular contraction was noted in 3 babies (11.5%) in group 1 and in one baby in group 2. Sinus tachycardia detected in 3 patients in only the group 1. None of the heart rate variability parameters were found to be statistically different between the two groups.Conclusions: Our study reassuringly demonstrated that umbilical venous catheter does not have any significant effect on arrhythmia or heart rate variability in preterm newborns. (Turk Arch Ped 2013; 48: 131-7)

Kadir Babao?lu; Murat Seringeç; Gürkan Altun; Selim Öncel; Ay?e Engin Ar?soy

2013-01-01

322

Autonomic dysfunction in HIV patients on antiretroviral therapy: studies of heart rate variability.  

DEFF Research Database (Denmark)

BACKGROUND: The presence of autonomic dysfunction in HIV patients is largely unknown. Early studies found autonomic dysfunction in patients with AIDS. Introduction of highly active antiretroviral combination therapy (ART) has dramatically changed the course of the disease and improved prognosis and decreased morbidity. At present it is not known whether introduction of ART also has decreased autonomic dysfunction. AIM: To evaluate whether autonomic dysfunction is present in an ART-treated HIV population. METHODS: HIV patients receiving ART for at least 3 years (n = 16) and an age-matched control group of healthy volunteers (n = 12) were included. All were non-smokers, non-diabetic and had never received medication for dyslipidaemia or hypertension. Following a 10 min resting period a 5 min ECG recording was performed. Heart rate variability (HRV) analysis was performed in accordance with current guidelines and data reported as median (interquartile range). RESULTS: The resting heart rate was higher in HIV patients compared with controls [69 (62-74) versus 57 (52-60); P<0.001]. Total HRV measured as standard deviation of normal-to-normal (SONN) was lower in the HIV group compared with the controls [36 (25-55) versus 74 (57-84) ms; P<0.01] as was parasympathetic activity measured as square root of the mean squared difference of successive normal-to-normal intervals (RMSSD) [22 (9-30) versus 35 (24-62) ms; P<0.05]. Low frequency power was lower in the HIV group compared with the control group [294 (161-602) versus 946 (711-1668) ms(2); P<0.01]. High frequency power as well as systolic and diastolic blood pressure did not differ between the groups. CONCLUSIONS: The HIV patients in ART have increased resting heart rate and decreased short-term heart rate variability indicating parasympathetic dysfunction.

Lebech, Anne-Mette; Kristoffersen, Ulrik Sloth

2007-01-01

323

A study of orthostatic hypotension, heart rate variability and baroreflex sensitivity in late-life depression.  

UK PubMed Central (United Kingdom)

BACKGROUND: To determine if subjects with late-life depression have significant cardiovascular autonomic abnormalities (orthostatic blood pressure drop, heart rate variability and baroreflex sensitivity). METHODS: A case-control study, in secondary care facilities, of forty two older (> 60 years) individuals with lifetime history of major depression and 31 age and sex matched comparison subjects. Autonomic function was assessed by measuring postural blood pressure, heart rate variability and baroreflex sensitivity using non-invasive beat-to-beat blood pressure and continuous ECG monitoring (Task Force® Monitor, CNSystems, Graz, Austria). The main outcome measures were maximal reduction in systolic blood pressure with active stand, low frequency and high frequency heart rate variability and baroreflex sensitivity using the sequence method. RESULTS: Participants with depression had a significantly larger drop in systolic blood pressure on standing from a supine position. Depression was an independent predictor for developing systolic orthostatic hypotension. Depressed participants also had lower low frequency heart rate variability and lower baroreflex sensitivity. LIMITATIONS: This was a cross-sectional and observational study; longitudinal effects or causality cannot be inferred from the findings and we could not distinguish state from trait related changes. CONCLUSIONS: Late-life depression has been associated with vascular disease but previous studies examining vascular risk factors have been inconsistent. Brain MRI white matter hyperintensities are ischemic and increased in late-life depression and associated with orthostatic blood pressure drops in animals. The presence of autonomic abnormalities in late-life depression may partly explain these inconsistencies and be associated with the development of brain white matter hyperintensities.

Vasudev A; O'Brien JT; Tan MP; Parry SW; Thomas AJ

2011-06-01

324

Job strain and heart rate variability in resident physicians within a general hospital.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To evaluate the association of heart rate variability with job strain in first year resident physicians. METHODS: We performed the study at the "Manuel Gea González" General Hospital in Mexico City. 54 resident doctors were studied over a period of 24 hr in their first year of specialization. Two questionnaires were administered: the first on general demographics, and the second, the Job Content Questionnaire. Heart rate variability was evaluated through the frequency domain (low-frequency power, high-frequency power, and low-frequency power/high-frequency power ratio) and time domain (SDNN). The doctors wore a Holter monitor over a 24-hr period, which included a workday plus their on-call time. They recorded their activities in a log. RESULTS: Compared to physicians in the "low strain" category, physicians working in the "passive" category had lower overall peak-to-peak cardiac variability (standard deviation of N-N intervals, SDNN), -9.08% (95% CI -17.97, 0.74), a -25% (95% CI -45.00, 0.22) lower high-frequency power, and -26.95% (95% CI -39.00, -12.53) lower low-frequency power. Physicians working in the "high strain" category had lower low-frequency power, -17.85% (95%CI -32.34, -0.25), and lower low-frequency/high-frequency ratio -24.29% (95% CI 38.08, 7.42) compared to those in the "low strain" category. CONCLUSIONS: High job strain and low job control among medical residents were associated with several indicators of lowered heart rate variability. Thus, analysis of heart rate variability may be an informative marker for evaluating the physiological impacts of workplace stressors.

Hernández-Gaytan SI; Rothenberg SJ; Landsbergis P; Becerril LC; De León-León G; Collins SM; Díaz-Vásquez FJ

2013-01-01

325

The prognostic significance of heart rate recovery is not dependent upon maximal effort in patients with heart failure.  

Science.gov (United States)

BACKGROUND: Heart rate recovery (HRR) has been observed to be a significant prognostic measure in patients with heart failure (HF). However, the prognostic value of HRR has not been examined in regard to the level of patient effort during exercise testing. Using the peak respiratory exchange ratio (RER) and a large multicenter HF database we examined the prognostic utility of HRR. METHODS: Cardiopulmonary exercise testing (CPX) was performed in 806 HF patients who then underwent an active cool-down of at least 1min. Peak oxygen consumption (VO(2)), ventilatory efficiency (VE/VCO(2) slope), and peak RER were determined with subjects categorized into subgroups according to peak RER (VCO(2) slope was the strongest predictor of adverse events (chi-square: 110.9, p<0.001) with both HRR (residual chi-square: 16.7, p<0.001) and peak VO(2) (residual chi-square: 10.4, p<0.01) adding significant prognostic value. CONCLUSIONS: HRR after symptom-limited exercise testing performed at sub-maximal efforts using RER to categorize level of effort is as predictive as HRR after maximal effort in HF patients. PMID:23391698

Cahalin, Lawrence P; Forman, Daniel E; Chase, Paul; Guazzi, Marco; Myers, Jonathan; Bensimhon, Daniel; Peberdy, Mary Ann; Ashley, Euan; West, Erin; Arena, Ross

2013-02-01

326

Arrhythmia and reduced heart rate variability during pregnancy in women with congenital heart disease and previous reparative surgery.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Tachyarrhythmia during pregnancy may have an adverse effect on the mother and the fetus. Heart rate variability (HRV) is a significant marker of autonomic nervous function and may predict tachyarrhythmia. HRV and incidence of arrhythmia in women with repaired congenital heart disease (CHD) during pregnancy were examined. METHODS: Twenty-eight patients with repaired CHD (35 pregnancies, age: 26+/-3.5 years at their first pregnancy, 22+/-6.2 years post-repair) and 19 healthy pregnant volunteers (controls, 19 pregnancies, age: 28+/-5.5 years) were enrolled. Holter monitoring and laboratory tests were examined at 28+/-4 weeks of gestation and 22+/-13 weeks postpartum in patients and 28+/-3 weeks of gestation in controls. Time and frequency variables of HRV were analyzed. RESULTS: Compared with controls and postpartum, there was a significantly higher incidence of tachyarrhythmia during pregnancy in women with CHD (4 episodes of supraventricular tachyarrhythmia (SVT) and 5 of non-sustained ventricular tachycardia, P=0.02). HR response in tetralogy of Fallot was impaired (781+/-50 ms, P=0.02). Most of HRV variables were significantly suppressed (average RR 740+/-64 ms, SDRR 99+/-22 ms, low and high frequency domains (341+/-165 ms2 and 256+/-181 ms2) (P<0.05). Reduced SDRR and high frequency domains were observed in patients with tachyarrhythmia. Furthermore, there were increased left ventricular end-diastolic dimensions 48+/-5 mm (P=0.001) and atrial natriuretic peptide levels 33+/-13 pg/ml (P=0.01) in the CHD patients compared with postpartum levels. CONCLUSIONS: Impaired autonomic nervous activity, volume overload of the heart and operative scar all play a contributory role in higher incidence of tachyarrhythmia during pregnancy in patients with repaired CHD compared to healthy pregnant controls. Close monitoring of patients with CHD for tachyarrhythmia during pregnancy is, thus, warranted.

Niwa K; Tateno S; Akagi T; Himeno W; Kawasoe Y; Tatebe S; Matsuo K; Gatzoulis MA; Nakazawa M

2007-11-01

327

Effect of bronchodilators on heart rate variability in patients with chronic obstructive pulmonary disease  

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Full Text Available Aim. To study effect of long-acting theophylline (Theotard, KRKA) and combination of salmeterol and fluticasone (Seretide, GlaxoSmithKline) on heart rhythm variability (HRV) and number of arrhythmic episodes in patients with chronic obstructive pulmonary disease (COPD).Material and methods. 144 patients with COPD and 35 patients of control group were examined. The analysis of HRV and Holter monitoring were made f on 2th and 14th days. Results. Treatment with both drugs led to increase in power of low- and high frequencies and their ratio (LF/HF), decrease in rate of supraventricular and ventricular arrhythmias. Theophylline therapy raised in a number of single and pair supraventricular extrasystoles. Treatment with combination of salmeterol and fluticasone did not change a number of extrasystoles.Conclusion. Combination of salmeterol and fluticasone is more preferable as a broncholytic therapy for patients with COPD and heart rhythm disorders.

H.H. Shugushev; M.V. Gurizeva; V.M. Vasilenko

2007-01-01

328

Noninvasive coronary angiography using 64-slice spiral computed tomography in an unselected patient collective: Effect of heart rate, heart rate variability and coronary calcifications on image quality and diagnostic accuracy  

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Objective: The aim of this study was to assess the impact of heart rate, heart rate variability and calcification on image quality and diagnostic accuracy in an unselected patient collective. Subjects and methods: One hundred and two consecutive patients with known or suspected coronary artery disease underwent both 64-MSCT and invasive coronary angiography. Image quality (IQ) was assessed by independent observers using a 4-point scale from excellent (1) to non-diagnostic (4). Accuracy of MSCT regarding detection or exclusion of significant stenosis (>50%) was evaluated on a per segment basis in a modified AHA 13-segment model. Effects of heart rate, heart rate variability, calcification and body mass index (BMI) on IQ and accuracy were evaluated by multivariate regression. IQ and accuracy were further analysed in subgroups of significant predictor variables and simple regression performed to calculate thresholds for adequate IQ. Results: Mean heart rate was 68.2 {+-} 13.3 bpm, mean heart rate variability 11.5 {+-} 16.0 beats per CT-examination (bpct) and median Agatston score 226.5. Average IQ score was 2 {+-} 0.6 whilst diagnostic quality was obtained in 89% of segments. Overall sensitivity, specificity, PPV or NPV was 91.2%, 99.2%, 95.3% or 98.3%. According to multivariate regression, overall IQ was significantly related to heart rate and calcification (P = 0.0038; P < 0.0001). The effect of heart rate variability was limited to IQ of RCA segments (P = 0.018); BMI was not related to IQ (P = 0.52). Calcification was the only predictor variable with significant effect on the number of non-diagnostic segments (P < 0.0001). In a multivariate regression, calcification was also the single factor with impact on diagnostic accuracy (P = 0.0049). Conclusion: Whilst heart rate, heart rate variability and calcification all show an inverse correlation to IQ, severe calcium burden remains the single factor with translation of such effect into decrease of diagnostic accuracy.

Brodoefel, H. [Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: h.brodoefel@t-online.de; Reimann, A. [Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Burgstahler, C. [Department of Cardiology, Eberhard-Karls-University, Otfried-Mueller-Str. 10, 72076 Tuebingen (Germany); Schumacher, F. [Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Herberts, T. [Department of Medical Biometry, Westbahnhofstr. 55, 72070 Tuebingen (Germany); Tsiflikas, I. [Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Schroeder, S. [Department of Cardiology, Eberhard-Karls-University, Otfried-Mueller-Str. 10, 72076 Tuebingen (Germany); Claussen, C.D.; Kopp, A.F.; Heuschmid, M. [Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)

2008-04-15

329

Effect of Green tea on Heart Rate of Male and Female  

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Full Text Available Camellia sinensis (Green tea) as a hot decoction is widely used throughout the Asia. Therefore to find out their effects on all the body functions are the need of hour, to recommend its safe use. In the current study the effect of Camellia sinensis on human (male and females) heart rate has been studied, by giving one cup of hot decoction of green tea to each subject of fifty four male and fifty four females. The heart rate per minute before and after the decoction was evaluated as; a great increase in the heart rate had been noted in case of males. Also a great decrease in the heart rate of individuals has been identified in case of females. From the current study it can be concluded that green tea have an effect of increasing heart rate in males and decreasing in the females, so the heart patients have to take care while using green tea.

Naveed Ullah; Mir Azam Khan; Afzal Haq Asif; Afrasiab Ali Shah; Sadaf Anwar; Hazrat Wahid; Aamir Nazir

2011-01-01

330

Effect of cold or thermoneutral water immersion on post-exercise heart rate recovery and heart rate variability indices.  

UK PubMed Central (United Kingdom)

This study aimed to investigate the effect of cold and thermoneutral water immersion on post-exercise parasympathetic reactivation, inferred from heart rate (HR) recovery (HRR) and HR variability (HRV) indices. Twelve men performed, on three separate occasions, an intermittent exercise bout (all-out 30-s Wingate test, 5 min seated recovery, followed by 5 min of submaximal running exercise), randomly followed by 5 min of passive (seated) recovery under either cold (CWI), thermoneutral water immersion (TWI) or control (CON) conditions. HRR indices (e.g., heart beats recovered in the first minute after exercise cessation, HRR(60)(s)) and vagal-related HRV indices (i.e., natural logarithm of the square root of the mean of the sum of the squares of differences between adjacent normal R-R intervals (Ln rMSSD)) were calculated for the three recovery conditions. HRR(60)(s) was faster in water immersion compared with CON conditions [30+/-9 beats min(-)(1) for CON vs. 43+/- 10 beats min(-)(1) for TWI (P=0.003) and 40+/-13 beats min(-)(1) for CWI (P=0.017)], while no difference was found between CWI and TWI (P=0.763). Ln rMSSD was higher in CWI (2.32+/-0.67 ms) compared with CON (1.98+/-0.74 ms, P=0.05) and TWI (2.01+/-0.61 ms, P=0.08; aES=1.07) conditions, with no difference between CON and TWI (P=0.964). Water immersion is a simple and efficient means of immediately triggering post-exercise parasympathetic activity, with colder immersion temperatures likely to be more effective at increasing parasympathetic activity.

Al Haddad H; Laursen PB; Chollet D; Lemaitre F; Ahmaidi S; Buchheit M

2010-08-01

331

The Development of a Microcontroller Based LowCost Heart Rate Counter for Health Care Systems  

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Full Text Available The heart rate is one of the significant physiological parameters of the human cardiovascular system. Heart rate is the number of times the heart beats per minute. Heart rate data reflects various physiological states such as biological workload, stress at work and concentration on tasks, drowsiness and the active state of the autonomic nervous system. Human cardiac dynamics are driven by the complex nonlinear interactions of two competing forces: sympathetic regulation increases and parasympathetic regulation decreases the heart rate. Thus, monitoring of heart rate plays a significant role in providing the status of cardiovascular system and clinically correlated information to medical professionals. Heart rate measurement is also regarded as an essential parameter in patient care monitoring system.Heart rate can be measured either by the ECG waveform or by sensing the pulse - the rhythmic expansion and contraction of an artery as blood is forced through it by the regular contractions of the heart. The pulse can be felt from those areas where the artery is close to the skin. This paper highlights on the design of a microcontroller (PIC series) based heart rate counter that is able to capture the pulse from finger tip by sensing the change in blood volume. The heart rates of fifteen healthy normal subjects (students of age 21-22 yrs.) both in relaxed and excited states were measured using the designed device and a standard heart rate measuring device. The outputs of the measured device were satisfactory. Also, the designed device, being noninvasive one, can easily find its place in health care monitoring system.

Souvik Das

2013-01-01

332

Immediate effect of slow pace bhastrika pranayama on blood pressure and heart rate.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The objective of this study was to evaluate the immediate effect of slow pace bhastrika pranayama (respiratory rate 6/min) for 5 minutes on heart rate and blood pressure and the effect of the same breathing exercise for the same duration of time (5 minutes) following oral intake of hyoscine-N-butylbromide (Buscopan), a parasympathetic blocker drug. SUBJECTS AND METHODS: Heart rate and blood pressure of volunteers (n = 39, age = 25-40 years) was recorded following standard procedure. First, subjects had to sit comfortably in an easy and steady posture (sukhasana) on a fairly soft seat placed on the floor keeping head, neck, and trunk erect, eyes closed, and the other muscles reasonably loose. The subject is directed to inhale through both nostrils slowly up to the maximum for about 4 seconds and then exhale slowly up to the maximum through both nostrils for about 6 seconds. The breathing must not be abdominal. These steps complete one cycle of slow pace bhastrika pranayama (respiratory rate 6/min). During the practice the subject is asked not to think much about the inhalation and exhalation time, but rather was requested to imagine the open blue sky. The pranayama was conducted in a cool, well-ventilated room (18-20 degrees C). After 5 minutes of this breathing practice, the blood pressure and heart rate again were recorded in the aforesaid manner using the same instrument. The other group (n = 10) took part in another study where their blood pressure and heart rate were recorded following half an hour of oral intake of hyoscine-N-butylbromide 20 mg. Then they practiced the breathing exercise as stated above, and the abovementioned parameters were recorded again to study the effect of parasympathetic blockade on the same pranayama. RESULTS: It was noted that after slow bhastrika pranayamic breathing (respiratory rate 6/min) for 5 minutes, both the systolic and diastolic blood pressure decreased significantly with a slight fall in heart rate. No significant alteration in both blood pressure and heart rate was observed in volunteers who performed the same breathing exercise for the same duration following oral intake of hyoscine-N-butylbromide. DISCUSSION: Pranayama increases frequency and duration of inhibitory neural impulses by activating pulmonary stretch receptors during above tidal volume inhalation as in Hering Bruer reflex, which bring about withdrawal of sympathetic tone in the skeletal muscle blood vessels, leading to widespread vasodilatation, thus causing decrease in peripheral resistance and thus decreasing the diastolic blood pressure. After hyoscine-N-butylbromide, the parasympathetic blocker, it was observed that blood pressure was not decreased significantly as a result of pranayama, as it was observed when no drug was administered. CONCLUSIONS: Vagal cardiac and pulmonary mechanisms are linked, and improvement in one vagal limb might spill over into the other. Baroreceptor sensitivity can be enhanced significantly by slow breathing (supported by a small reduction in the heart rate observed during slow breathing and by reduction in both systolic and diastolic pressure). Slow pace bhastrika pranayama (respiratory rate 6/min) exercise thus shows a strong tendency to improving the autonomic nervous system through enhanced activation of the parasympathetic system.

Pramanik T; Sharma HO; Mishra S; Mishra A; Prajapati R; Singh S

2009-03-01

333

Entertainment Capture through Heart Rate Activity in Physical Interactive Playgrounds  

DEFF Research Database (Denmark)

An approach for capturing and modeling individual entertainment (“fun”) preferences is applied to users of the innovative Playware playground, an interactive physical playground inspired by computer games, in this study. The goal is to construct, using representative statistics computed from children’s physiological signals, an estimator of the degree to which games provided by the playground engage the players. For this purpose children’s heart rate (HR) signals, and their expressed preferences of how much “fun” particular game variants are, are obtained from experiments using games implemented on the Playware playground. A comprehensive statistical analysis shows that children’s reported entertainment preferences correlate well with specific features of the HR signal. Neuro-evolution techniques combined with feature set selection methods permit the construction of user models that predict reported entertainment preferences given HR features. These models are expressed as artificial neural networks and are demonstrated and evaluated on two Playware games and two control tasks requiring physical activity. The best network is able to correctly match expressed preferences in 64% of cases on previously unseen data (p?value 6 · 10?5). The generality of the methodology, its limitations, its usability as a real-time feedback mechanism for entertainment augmentation and as a validation tool are discussed. Udgivelsesdato: February

Yannakakis, Georgios; Hallam, John

2008-01-01

334

Wireless and portable heart rate variability monitor device  

UK PubMed Central (United Kingdom)

The invention relates to a wireless and portable heart rate variability monitor device in the technical field of medical testing, which comprises an electrocardiograph acquisition module, a data processing module, a wireless transmission module and a human-computer interaction module, wherein the input end and the output end of the data processing module are respectively connected with the electrocardiograph acquisition module and the wireless transmission module to receive original electrocardiograph analog signals and output digital electrocardiograph data and the human-computer interactionmodule is connected with the data processing module to receive the digital electrocardiograph data and output user instructions. The device can directly carry out calculation and display of HRV parameters on the device, or can use Zigbee protocol to transmit related data to an upper computer in a wireless way and then conduct follow-up processing. In order to reduce the power consumption of wireless transmission, the electrocardiograph data is defaulted and not uploaded in real time, while abnormal electrocardiograph data is unloaded after data acquisition. Compared with the prior art, the external hardware circuit is greatly simplified, the volume and power consumption of the monitor device are greatly reduced, and the monitor device is more applicable for carrying about.

JINHAI NIU; MENG CUI; LAN LUO; YISHENG ZHU; SHANBAO TONG

335

Gender differences in personality and heart-rate variability.  

UK PubMed Central (United Kingdom)

Both personality traits and autonomic functioning show as gender differences, but their relationship is not well understood. Medically unexplained symptoms are related to personality features and can be assessed by autonomic measurement. The patterns are hypothesised to identify gender differences. We recruited 30 male and 30 female healthy volunteers. All participants completed the Tridimensional Personality Questionnaire (TPQ) and heart-rate variability (HRV) measurement. Correlation analysis was performed to identify the relationships between TPQ scores and HRV parameters. For the subjects as a whole, the subdimension harm avoidance 4 (HA4, fatigability and asthenia) was found to be negatively correlated with low-frequency (LF) power, high-frequency (HF) power and total power (TP) of HRV. Novelty seeking 1 (NS1, exploratory excitability) was found to be positively correlated with LF power and TP. Multiple linear regression analysis revealed that the interactions exploratory excitability x gender and fatigability x gender are predictors of LF and HF power, respectively. Our result supports the hypothesis that personality features such as exploratory excitability and fatigability are associated with autonomic functioning and that gender is a moderator in these relationships.

Huang WL; Chang LR; Kuo TB; Lin YH; Chen YZ; Yang CC

2013-03-01

336

Empirical Mode Decomposition Analysis of Heart Rate Variability  

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Full Text Available The analysis of heart rate variability (HRV) demands specific capabilities not provided by either parametric or nonparametric spectral estimation methods. Empirical mode decomposition (EMD) has the possibility of dealing with nonstationary and nonlinear embedded phenomena, for a proper assessment of dynamic and transient changes in amplitude and time scales of HRV signal. In this work EMD and a non-linear curve fitting technique are used to study half an hour HRV signal and its intrinsic mode function obtained from 20 healthy young control subjects, 20 healthy old control subjects and 20 subjects with long term ST. The intrinsic oscillations are measured by means of its meanperiod and variance. Significant meanperiod reduction is observed in the intrinsic time scales of healthy old control subjects and subjects with long term ST, which is used to classify the three groups of HRV signal with high sensitivity and specificity. The estimated slope using the non-linear curve fitting technique represents the flexibility of the cardiovascular system. The main advantage of this method is it does not make any prior assumption about the HRV signal being analyzed and no artificial information is introduced into the filtering method.

C. Santhi; N. Kumaravel

2010-01-01

337

[Heart rate variability in offspring of hypertensive parents].  

UK PubMed Central (United Kingdom)

UNLABELLED: The aim of the study was the assessment of power spectrum of heart rate variability in young people with family history of hypertension. The study included healthy subjects in their second or third decade of their life. According to the family history of hypertension, the following groups were specified: group A--both parents hypertensive (n = 30, age = 24.5 +/- 4.0 years), group B--only one parent hypertensive (n = 94, age = 24.1 +/- 5.1 years) and group C--both parents normotensive (n = 35, age = 25.9 +/- 7.4 years). METHODS: HRV analysis was performed using CardioPSA System, Medatec, Belgium. In every person, 30 minute ECG was assessed: 15 min.lying, 15 min standing. For data analysis Fast Fourier transform was used, total variability, LF (0.04-0.15 Hz) and HF (0.15-0.40, Hz) components were calculated. We observed similar values of HRV components in all groups. Subjects with family history of hypertension showed however a tendency towards higher LF values in lying position. Standing caused in all groups decrease of total variability, increase of LF component and decrease of HF component. Changes were less pronounced in subjects with both parents hypertensive. Young adults with both parents hypertensive have shown a tendency towards higher values of LF component and less pronounced changes of HRV components after standing up.

Stolarz K; Grodzicki T; Lubaszewski W; Adamkiewicz-Piejko A; Olszanecka A; Kawecka-Jaszcz K

2002-01-01

338

Muscle metaboreflex and autonomic regulation of heart rate in humans.  

Science.gov (United States)

We elucidated the autonomic mechanisms whereby heart rate (HR) is regulated by the muscle metaboreflex. Eight male participants (22 ± 3 years) performed three exercise protocols: (1) enhanced metaboreflex activation with partial flow restriction (bi-lateral thigh cuff inflation) during leg cycling exercise, (2) isolated muscle metaboreflex activation (post-exercise ischaemia; PEI) following leg cycling exercise, (3) isometric handgrip followed by PEI. Trials were undertaken under control (no drug), ?1-adrenergic blockade (metoprolol) and parasympathetic blockade (glycopyrrolate) conditions. HR increased with partial flow restriction during leg cycling in the control condition (11 ± 2 beats min(-1); P 0.05 between conditions). During PEI following handgrip, HR was similarly elevated from rest under control and parasympathetic blockade (4 ± 1 vs. 4 ± 2 beats min(-1); P > 0.05 between conditions) conditions, but attenuated with ?-adrenergic blockade (0.2 ± 1 beats min(-1); P > 0.05 vs. rest). Thus muscle metaboreflex activation-mediated increases in HR are principally attributable to increased cardiac sympathetic activity, and only following exercise with a large muscle mass (PEI following leg cycling) is there a contribution from the partial withdrawal of cardiac parasympathetic tone. PMID:23713032

Fisher, James P; Adlan, Ahmed M; Shantsila, Alena; Secher, J Frederik; Sørensen, Henrik; Secher, Niels H

2013-05-27

339

Estimation of human core temperature from sequential heart rate observations.  

UK PubMed Central (United Kingdom)

Core temperature (CT) in combination with heart rate (HR) can be a good indicator of impending heat exhaustion for occupations involving exposure to heat, heavy workloads, and wearing protective clothing. However, continuously measuring CT in an ambulatory environment is difficult. To address this problem we developed a model to estimate the time course of CT using a series of HR measurements as a leading indicator using a Kalman filter. The model was trained using data from 17 volunteers engaged in a 24 h military field exercise (air temperatures 24-36 °C, and 42%-97% relative humidity and CTs ranging from 36.0-40.0 °C). Validation data from laboratory and field studies (N = 83) encompassing various combinations of temperature, hydration, clothing, and acclimation state were examined using the Bland-Altman limits of agreement (LoA) method. We found our model had an overall bias of -0.03 ± 0.32 °C and that 95% of all CT estimates fall within ±0.63 °C (>52 000 total observations). While the model for estimating CT is not a replacement for direct measurement of CT (literature comparisons of esophageal and rectal methods average LoAs of ±0.58 °C) our results suggest it is accurate enough to provide practical indication of thermal work strain for use in the work place.

Buller MJ; Tharion WJ; Cheuvront SN; Montain SJ; Kenefick RW; Castellani J; Latzka WA; Roberts WS; Richter M; Jenkins OC; Hoyt RW

2013-07-01

340

Increased heart rate and atherosclerosis: Potential implications of ivabradine therapy  

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Full Text Available Despite all the therapeutic advances in the field of cardiology, cardiovascular diseases, and in particular coronary artery disease, remain the leading cause of death and disability worldwide, thereby underlining the importance of acquiring new therapeutic options in this field. A reduction in elevated resting heart rate (HR) has long been postulated as a therapeutic approach in the management of cardiovascular disease. An increased HR has been shown to be associated with increased progression of coronary atherosclerosis in animal models and patients. A high HR has also been associated with a greatly increased risk of plaque rupture in patients with coronary atherosclerosis. Endothelial function may be an important link between HR and atherosclerosis. An increased HR has been shown experimentally to cause endothelial dysfunction. Inflammation plays a significant role in the pathogenesis and progression of atherosclerosis. In the literature, there is data that shows an association between HR and circulating markers of vascular inflammation. In addition, HR reduction by pharmacological intervention with ivabradine (a selective HR-lowering agent that acts by inhibiting the pacemaker ionic current If in sinoatrial node cells) reduces the formation of atherosclerotic plaques in animal models of lipid-induced atherosclerosis. The aim of this editorial is to review the possible role of ivabradine on atherosclerosis.

Alberto Dominguez-Rodriguez; Gabriela Blanco-Palacios; Pedro Abreu-Gonzalez

2011-01-01