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1

Correlation between heart rate and performance during Olympic windsurfing competition  

Microsoft Academic Search

  \\u000a The aim of this study was to examine the heart rate (HR) response to Olympic windsurfing competition and to check if there\\u000a was any correlation between racing HR, performance, and the variables measured during laboratory maximal exercise. Ten elite\\u000a windsurfers [age: 20.93 (3.46) years; height: 178.10 (6.34) cm; body mass: 66.79 (5.90) kg] performed a laboratory maximal\\u000a oxygen consumption (VO2max) trial and

Karim Chamari; Imen Moussa-Chamari; Olivier Galy; Mustapha Chaouachi; Donia Koubaa; Chokri Ben Hassen; Olivier Hue

2003-01-01

2

Heart rate recovery predicts memory performance in older adults.  

PubMed

The current study examined cardiovascular reactivity and recovery during memory testing in a sample of 28 younger and 28 older adults. Heart rate (HR) levels were measured before, during, and after a memory test (word list recall). Contrary to prediction, older adults did not have a blunted cardiovascular response to memory tasks compared to younger adults. Word list recall performance was predicted by both Age and an Age x HR recovery interaction. As expected, younger adults performed better on the word list task than older adults. In addition, older adults with better posttest HR recovery performed significantly better than older adults with poor posttest HR recovery, whereas HR recovery differences in younger adults were inconsequential. These relationships were not affected by subjective appraisals of anxiety and task difficulty. Overall, cardiac dysregulation, seen here as low HR recovery, represents an important, potentially modifiable, factor in memory performance in older adults. In addition to being beneficial to overall health, interventions designed to help older adults regulate their HR responses may help offset certain memory declines. PMID:19760500

Pearman, Ann; Lachman, Margie E

2009-09-17

3

Correlation between heart rate and performance during Olympic windsurfing competition.  

PubMed

The aim of this study was to examine the heart rate (HR) response to Olympic windsurfing competition and to check if there was any correlation between racing HR, performance, and the variables measured during laboratory maximal exercise. Ten elite windsurfers [age: 20.93 (3.46) years; height: 178.10 (6.34) cm; body mass: 66.79 (5.90) kg] performed a laboratory maximal oxygen consumption (.VO(2max)) trial and national windsurf competitions wearing a HR monitor. One hundred and forty-three individual races were examined. Racing HR was expressed as a percentage of (1) HR(max) (maximal treadmill HR) and (2) HR(reserve) (HR(max)-HR(rest)). The performance (racing classification: RC, which is inversely proportional to performance) was significantly correlated to the racing HR response in both light wind (LW): LW-RC=-0.12(%HR(reserve))+13.03; r=-0.71, r(2)=0.50, p<0.001, and medium wind (MW): MW-RC=-0.11(%HR(reserve))+10.99; r=-0.66, r(2)=0.43, p<0.001. The results showed similar correlations between performance and %HR(max). Post racing lactate concentration was higher in LW compared to MW [7.14 (0.21) and 5.18 (2.02) mmol.l(-1), respectively]. There was a negative correlation between the highest racing HR (%HR(reserve)) of each athlete and the second ventilatory threshold expressed as a percentage of .VO(2max) ( r=-0.71, p<0.05). To summarize, this study showed that light and medium wind Olympic windsurfing performances are highly dependent on the capacity of the athlete to maintain a high HR for long periods of time. Furthermore, windsurfing is highly dependent on the athlete's physical fitness level as shown by the correlations between racing HRs and laboratory physiological variables. PMID:12682836

Chamari, Karim; Moussa-Chamari, Imen; Galy, Olivier; Chaouachi, Mustapha; Koubaa, Donia; Hassen, Chokri Ben; Hue, Olivier

2003-04-01

4

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

PubMed

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

5

Cognitive Performance and Heart Rate Variability: The Influence of Fitness Level  

PubMed Central

In the present study, we investigated the relation between cognitive performance and heart rate variability as a function of fitness level. We measured the effect of three cognitive tasks (the psychomotor vigilance task, a temporal orienting task, and a duration discrimination task) on the heart rate variability of two groups of participants: a high-fit group and a low-fit group. Two major novel findings emerged from this study. First, the lowest values of heart rate variability were found during performance of the duration discrimination task, compared to the other two tasks. Second, the results showed a decrement in heart rate variability as a function of the time on task, although only in the low-fit group. Moreover, the high-fit group showed overall faster reaction times than the low-fit group in the psychomotor vigilance task, while there were not significant differences in performance between the two groups of participants in the other two cognitive tasks. In sum, our results highlighted the influence of cognitive processing on heart rate variability. Importantly, both behavioral and physiological results suggested that the main benefit obtained as a result of fitness level appeared to be associated with processes involving sustained attention.

Luque-Casado, Antonio; Zabala, Mikel; Morales, Esther; Mateo-March, Manuel; Sanabria, Daniel

2013-01-01

6

The effect of feedback-assisted reduction in heart rate reactivity on videogame performance  

Microsoft Academic Search

In 67 male volunteers, we examined the reduction of cardiovascular responsivity to a psychomotor challenge (videogame) achieved by use of heart rate (HR) feedback and effects of these procedures on concomitant behavioral performance. Each subject participated in a pretraining assessment of his cardiovascular responses to the videogame, a training condition, and a posttraining assessment identical to the initial evaluation. During

Kevin T. Larkin; Stephen B. Manuck; Alfred L. Kasprowicz

1990-01-01

7

Heart Rate and Exercise  

NSDL National Science Digital Library

In this activity about heart health (on page 27 of the PDF), learners measure their heart rates after a variety of physical activities and compare the results with their resting heart rates, and with the heart rates of other learners in their groups. Learners also make predictions about their pulse rates. This lesson guide includes background information, setup and management tips, extension ideas, information about the heart in space and a handout.

Tharp, Barbara Z.; Erdmann, Deanne B.; Matyas, Marsha L.; Mcneel, Ronald L.; Moreno, Nancy P.

2009-01-01

8

Effect of 30% Oxygen Administration on Verbal Cognitive Performance, Blood Oxygen Saturation and Heart Rate  

Microsoft Academic Search

This study investigated the effect of 30% oxygen administration on verbal cognitive performance, blood oxygen saturation, and heart rate. Five male (24.6(±0.9) years) and five female (22.2(±1.9) years) college students were selected as the subjects for this study. Two psychological tests were developed to measure the performance level of verbal cognition. The experiment consisted of two runs: one was a

Soon-Cheol Chung; Sunao Iwaki; Gye-Rae Tack; Jeong-Han Yi; Ji-Hye You; Ji-Hun Kwon

2006-01-01

9

Increased heart rate variability and executive performance after aerobic training in the elderly  

Microsoft Academic Search

This study examined the effects of two short physical training programs on various parameters of heart rate variability (HRV)\\u000a and on executive performance in older people. Twenty-four sedentary men and women aged 65–78 years were randomly assigned\\u000a to an aerobic exercise program or a stretching program three times a week for 12 weeks. Resting HRV was measured in time and\\u000a frequency domains

Cédric T. Albinet; Geoffroy Boucard; Cédric A. Bouquet; Michel Audiffren

2010-01-01

10

Glucose administration, heart rate and cognitive performance: effects of increasing mental effort  

Microsoft Academic Search

Rationale: It is known that glucose administration is capable of improving performance on tests of declarative verbal memory and non-mnemonic\\u000a tasks requiring high ”mental effort”. At the same time, cognitively demanding tasks are associated with elevated heart rate,\\u000a a response that could feasibly be part of a physiological mechanism serving to increase the delivery of glucose to active\\u000a brain substrates.

David O. Kennedy; Andrew B. Scholey

2000-01-01

11

The effect of heart rate variability biofeedback on performance psychology of basketball players.  

PubMed

Coping with pressure and anxiety is an ineluctable demand of sports performance. Heart rate variability (HRV) Biofeedback (BFB) shall be used as a tool for self regulating physiological responses resulting in improved psycho physiological interactions. For further analysis, the present study has been designed to examine the relationship between anxiety and performance and also effectiveness of biofeedback protocol to create stress-eliciting situation in basketball players. Thirty basketball players of university level and above (both male and female) aged 18-28 years, who scored a minimum of 20 in state trait anxiety inventory, were randomly divided into three equal groups- Experimental (Biofeedback) group, Placebo group and Control (No Treatment) group. The BFB group received HRV BFB training for 10 consecutive days for 20 min that included breathing at individual's resonant frequency through a pacing stimulus; Placebo group was shown motivational video clips for 10 consecutive days for 10 min, whereas No Treatment Control group was not given any intervention. Two way repeated measure ANOVA was applied to analyze the differences within and between the groups. Anxiety, coping self-efficacy, heart rate variability, respiration rate, and performance (dribbling, passing and shooting) at session 1, 10 and 1 month follow up were statistically significant in each group along with interaction of group and time (p < 0.001). Also, all the measures showed statistically significant inter group difference (p < 0.05). The findings are harmonious with existing data on HRV BFB as a strategy for dealing with anxiety. The Placebo group showed improvement in self efficacy and performance post training. The Control group showed no change in any variable except performance. The results of the study support the idea that HRV BFB lowers the anxiety and thus there seems to be a potential association between HRV BFB and performance optimization. PMID:22402913

Paul, Maman; Garg, Kanupriya

2012-06-01

12

Heart Rate adjustment of ST segment depression and performance of the exercise electrocardiogram: A critical evaluation  

Microsoft Academic Search

Analysis of the rate-related change in exercise-induced ST segment depression using the exercise ST segment\\/heart rate slope and ST segment\\/heart rate index can improve the accuracy of the exercise electrocardiogram (ECG) for the identification of patients with coronary artery disease, recognition of patients with anatomically or functionally severe coronary obstruction and detection of patients at increased risk for future coronary

Peter M. Okin; Paul Kligfield

1995-01-01

13

Heart failure performance measures: do they have an impact on 30-day readmission rates?  

PubMed

Congestive heart failure (CHF) accounts for more health care costs than any other diagnosis. Readmissions contribute to this expenditure. The authors evaluated the relationship between adherence to performance metrics and 30-day readmissions. This was a retrospective study of 6063 patients with CHF between 2001 and 2008. Data were collected for 30-day readmissions and compliance with CHF performance measures at discharge. Rates of readmission for CHF increased from 16.8% in 2002 to 24.8% in 2008. Adherence to performance measures increased concurrently from 95.8% to 99.9%. Except for left ventricular function (LVF) assessment, the 30-day readmission rate was not associated with adherence to performance measures. Readmitted patients had twice the odds of not having their LVF assessed (odds ratio = 2.0; P < .00005; 95% confidence interval = 1.45-2.63). CHF performance measures, except for the LVF assessment, have little relationship to 30-day readmissions. Further studies are needed to identify performance measures that correlate with quality of care. PMID:23110998

Mazimba, Sula; Grant, Nakash; Parikh, Analkumar; Mwandia, George; Makola, Diklar; Chilomo, Christine; Redko, Cristina; Hahn, Harvey S

2012-10-30

14

Heart Rate Variability in Heart Failure  

Microsoft Academic Search

The autonomic nervous system has an important role in the development and progression of the heart failure syndrome. Increased sympathetic, reduced parasympathetic, and impaired baroreceptor activity are well-documented features of heart failure. The analysis of heart rate variability can give insight into these autonomic abnormalities. A number of techniques now exist for assessing heart rate variability, and in general they

John E. Sanderson

1998-01-01

15

Assessment of mortality rates for congenital heart defects and surgeons’ performance  

Microsoft Academic Search

Background. In the absence of reliable national data, we have collected results of all operations for congenital heart defects from five departments to assess mortality rates and compare them among surgeons and departments.Methods. Data relating to all operations (2,718) carried out at the five centers during a period from April 1, 1997 through March 31, 1999. Clearly defined criteria were

Jaroslav F Stark; Steve Gallivan; Katie Davis; John R. L Hamilton; James L Monro; James C. S Pollock; Kevin G Watterson

2001-01-01

16

Consecutive days of cold water immersion: effects on cycling performance and heart rate variability.  

PubMed

We investigated performance and heart rate (HR) variability (HRV) over consecutive days of cycling with post-exercise cold water immersion (CWI) or passive recovery (PAS). In a crossover design, 11 cyclists completed two separate 3-day training blocks (120 min cycling per day, 66 maximal sprints, 9 min time trialling [TT]), followed by 2 days of recovery-based training. The cyclists recovered from each training session by standing in cold water (10 °C) or at room temperature (27 °C) for 5 min. Mean power for sprints, total TT work and HR were assessed during each session. Resting vagal-HRV (natural logarithm of square-root of mean squared differences of successive R-R intervals; ln rMSSD) was assessed after exercise, after the recovery intervention, during sleep and upon waking. CWI allowed better maintenance of mean sprint power (between-trial difference [90 % confidence limits] +12.4 % [5.9; 18.9]), cadence (+2.0 % [0.6; 3.5]), and mean HR during exercise (+1.6 % [0.0; 3.2]) compared with PAS. ln rMSSD immediately following CWI was higher (+144 % [92; 211]) compared with PAS. There was no difference between the trials in TT performance (-0.2 % [-3.5; 3.0]) or waking ln rMSSD (-1.2 % [-5.9; 3.4]). CWI helps to maintain sprint performance during consecutive days of training, whereas its effects on vagal-HRV vary over time and depend on prior exercise intensity. PMID:22752345

Stanley, Jamie; Peake, Jonathan M; Buchheit, Martin

2012-07-03

17

Comparison of mathematically determined blood lactate and heart rate "threshold" points and relationship with performance.  

PubMed

The purpose of this study was to investigate the relationship between threshold points for heart rate (Thfc) and blood lactate (Thla) as determined by two objective mathematical models. The models used were the mono-segmental exponential (EXP) model of Hughson et al. and the log-log (LOG) model of Beaver et al. Inter-correlations of these threshold points and correlations with performance were also studied. Seventeen elite runners (mean, SD = 27.5, 6.5 years; 1.73, 0.05 m; 63.8, 7.3 kg; and maximum oxygen consumption of 67.8, 3.7 ml.kg-1.min-1) performed two maximal multistage running field tests on a 183.9-m indoor track with inclined turns. The initial speed of 9 km.h-1 (2.5 m.s-1) was increased by 0.5 km.h-1 (0.14 m.s-1) every lap for the fc test and by 1 km.h-1 (0.28 m.s-1) every 4 min for the la test. After fitting the la or the fc data to the two mathematical models, the threshold speed was assessed in the LOG model from the intersection of the two linear segments (LOG-la; LOG-fc) and in the EXP model from a tangent point (TI-la; TI-fc). Thla and Thfc speeds computed with the two models were significantly different (P less than 0.001) and poorly correlated (LOG-la vs LOG-fc: r = 0.36, TI-la vs TI-fc: r = 0.13). In general, Thfc were less well correlated with performance than Thla. With two different objective mathematical models, this study has shown significant differences and poor correlations between Thla and Thfc.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1592055

Tokmakidis, S P; Léger, L A

1992-01-01

18

Evaluation of Weight Factor Mode and EEMD performance on measuring heart rate activity in the presence of cardiac arrhythmia  

Microsoft Academic Search

In this work we aim at evaluating the performance of our previously proposed method Weight Factor Mode (WFM), which is based on Ensemble Empirical Mode Decomposition (EEMD), in the case of cardiac arrhythmia. For this, we have used MIT-BIH Arrhythmia ECG database. Obtained results show high sensitivity detecting the heart rate activity (99.5%). We also found that, in order to

Mohamed Kharrat; Yuki Wakuda; Shinsuke Kobayashi; Noboru Koshizuka; Ken Sakamura

2012-01-01

19

Reduced Heart Rate Volatility  

PubMed Central

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

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

2004-01-01

20

Heart rate conditioning in newborn infants: Relationships among conditionability, heart rate variability, and sex  

Microsoft Academic Search

Evaluated trace conditioning in 20 newborn infants by examining heart rate responses to the conditioned stimulus (CS), in anticipation of the unconditioned stimulus (UCS) and in the absence of the UCS. 2 sets of analyses were performed using subgroups based on preexperimental heart rate variability and sex. Preexperimental heart rate variability was related only to the response to the CS,

Leighton E. Stamps; Stephen W. Porges

1975-01-01

21

The impact of a naturalistic hands-free cellular phone task on heart rate and simulated driving performance in two age groups  

Microsoft Academic Search

Heart rate and driving performance were assessed while late middle age (51–66) and younger adults (19–23) engaged in a naturalistic hands free phone task that was designed to place objectively equivalent cognitive demands on all participants. Although heart rate measures have been used in evaluating driver workload, prior studies had not compared responses in late middle age and younger adults

Bryan Reimer; Bruce Mehler; Joseph F. Coughlin; Nick Roy; Jeffery A. Dusek

2011-01-01

22

Nonlinear analysis of the performance and reliability of wavelet singularity detection based denoising for doppler ultrasound fetal heart rate signals  

Microsoft Academic Search

Many studies on the physiology of the cardiovascular system revealed that nonlinear chaotic dynamics govern the generation of the heart rate signal. This is also valid for the fetal heart rate (FHR) variability, where however the variability is affected by many more factors and is significantly more complicated than for the adult case. Recently an adaptive wavelet denoising method for

S. Papadimitriou; A. Bezerianos

1999-01-01

23

Heart Rates of Elite Synchronized Swimmers.  

ERIC Educational Resources Information Center

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

Gemma, Karen Erickson; Wells, Christine L.

1987-01-01

24

Heart Rate Variability, Prefrontal Neural Function, and Cognitive Performance: The Neurovisceral Integration Perspective on Self-regulation, Adaptation, and Health  

Microsoft Academic Search

Background  In the present paper, we describe a model of neurovisceral integration in which a set of neural structures involved in cognitive,\\u000a affective, and autonomic regulation are related to heart rate variability (HRV) and cognitive performance.\\u000a \\u000a \\u000a \\u000a Methods  We detail the pathways involved in the neural regulation of the cardiovascular system and provide pharmacological and neuroimaging\\u000a data in support of the neural structures

Julian F. Thayer; Anita L. Hansen; Evelyn Saus-Rose; Bjorn Helge Johnsen

2009-01-01

25

Effects of Ramadan Fasting on Body Composition, Aerobic Performance and Lactate, Heart Rate and Perceptual Responses in Young Soccer Players  

PubMed Central

The purpose of this study was to examine the effects of Ramadan fasting on body composition, aerobic exercise performance and blood lactate, heart rate and perceived exertion in regularly trained young soccer players. Sixteen male soccer players participated in this study. Mean age, stature, body mass and training age of the players were 17.4±1.2 years, 175.4±3.6 cm, 69.6±4.3 kg and 5.1±1.3 years, respectively. During the Ramadan period, all subjects voluntarily chose to follow the fasting guidelines and abstained from eating and drinking from sunrise to sunset. Body composition, hydration status, dietary intake and sleep duration were assessed on four occasions: before Ramadan, at the beginning of Ramadan, at the end of Ramadan and 2 weeks after the end of Ramadan. On each occasion, aerobic exercise performance and blood lactate, heart rate and rating of perceived exertion responses of players were also determined during an incremental running test. Repeated measures of ANOVA revealed that body mass, percentage of body fat, fat-free mass, hydration status, daily sleeping time and daily energy and macronutrient intake of players did not vary significantly throughout the study period (p>0.05). However, players experienced a small but significant decrease in skinfold thicknesses over the course of the study (p<0.05). Although ratings of perceived exertion at submaximal workloads increased during Ramadan (p<0.05), blood lactate and heart rate responses had decreased by the end of Ramadan (p<0.05). In line with these changes, peak running performance and running velocity at anaerobic threshold also improved by the end of Ramadan (p<0.05). Improvements in aerobic exercise performance with time were probably due to the effects of pre-season training program that was performed after the break of the fast (Iftar) during the month of Ramadan. The results of the present study suggest that if regular training regimen, body fluid balance, daily energy intake and sleep duration are maintained as before Ramadan, Ramadan fasting does not have detrimental effects on aerobic exercise performance or body composition in young soccer players.

Guvenc, Alpay

2011-01-01

26

Heart rate and heart rate variability, a pharmacological target  

Microsoft Academic Search

Heart rate varies with respiration, blood pressure, emotion, etc., and heart rate variability (HRV) is presently one of the best indices to predict fatal issues in cardiac failure and after myocardial infarction. HRV depends on various reflexes. In addition, parallel studies of HRV and the myocardial adrenergic and muscarinic transduction system in experimental models of cardiac hypertrophy (CH) have suggested

Bernard Swynghedauw; Sylvain Jassonfl; Brigitte Chevalierfl; Jean Clairambault; Sandrine Hardouinfl; Christophe Heymesfl; Laurence Mangin; Pascale Manster; Claire Médigue; Jean-Marie Moalic; Nancy Thibault; François Carré

1997-01-01

27

Heart rate variability: a review  

Microsoft Academic Search

Heart rate variability (HRV) is a reliable reflection of the many physiological factors modulating the normal rhythm of the\\u000a heart. In fact, they provide a powerful means of observing the interplay between the sympathetic and parasympathetic nervous\\u000a systems. It shows that the structure generating the signal is not only simply linear, but also involves nonlinear contributions.\\u000a Heart rate (HR) is

U. Rajendra Acharya; Paul K. Joseph; N. Kannathal; Choo Min Lim; Jasjit S. Suri

2006-01-01

28

Heart rates during competitive orienteering  

Microsoft Academic Search

This study investigated the heart rate profiles of 16 experienced, competitive orienteers (aged 15-62 years) during three competitive events. Each competitor was assessed over three different types of course which were classified as: fast run (FR), slow run (SR) and highly physical (HP). The results showed that all subjects recorded heart rates that were between 140 and 180 beats min-1

S R Bird; R Bailey; J Lewis

1993-01-01

29

The Effects of an Intervention Strategy on Children's Heart Rates and Skill Performance  

ERIC Educational Resources Information Center

|The purpose of this project was to examine the effectiveness of a fitness infusion instructional strategy (FI) on children's activity levels and skill performance scores. This strategy included aerobic activity within the skill practice tasks and game play. In other words, students performed short bouts of activity between the practice and…

Ignico, Arlene; Corson, Arleen; Vidoni, Carla

2006-01-01

30

Assessment of gravitational stress on heart rate variability during maneuvers on high performance jet flights.  

PubMed

The Push-Pull Effect (PPE) is a physiological phenomenon defined as a reduction of +Gz tolerance induced by a previous exposure to a -Gz acceleration, that may lead to loss of consciousness. Aim of this study was to evaluate, for the first time, the cardiac rhythm changes associated with PPE during real flights. Data were collected in 3 pilots during flights on the Aermacchi MB- 339-CD aircraft. In each flight, lasting about 60 minutes, ECG, respiration and 3D accelerations were recorded by a new smart garment (the MagIC System). The flight protocol included a maneuver eliciting a reference +5Gz acceleration for 15 seconds (Ref+5G), followed, after a while, by a push-pull maneuver with a profile characterized by a 5-s acceleration at -1Gz (PP-1G) and, with a 1G/s onset, by 15 seconds at +5Gz (PP+5G), so to induce the push-pull gravitational stress. From each ECG recording, a beat-by-beat RR Interval (RRI) series was derived. RRI mean, standard deviation (SDNN) and the RRI Root Mean Square of Successive Difference (RMSSD) were estimated in each pilot during the Ref+5G and the PP+5G maneuvers. As compared with Ref+5G, all pilots displayed significant reductions in RRI mean, SDNN and RMSSD during PP+5G. These findings are compatible with a PP-induced enhancement in the sympathetic drive to the heart -as shown by the reduction in RRI mean and SDNN- and a concomitant deactivation of the parasympathetic control as shown by the reduction in RMSSD. PMID:21097262

Di Rienzo, Marco; Castiglioni, Paolo; Meriggi, Paolo; Rizzo, Francesco; Trivelloni, Pierandrea; Cacopardo, Salvatore; Guadagno, Anton Giulio

2010-01-01

31

The Effects of Cognitive Appraisal of Stress on Heart Rate and Task Performance.  

National Technical Information Service (NTIS)

In aviation occupations, performance impairment under stress conditions is particularly undesirable. However, individuals may show differing amounts of impairment under stress, and the reasons for these differences are not clear. The present study explore...

R. I. Thackray D. W. Pearson

1968-01-01

32

The Influence of Heart Rate on the Doppler-Derived Myocardial Performance Index  

Microsoft Academic Search

The Doppler-derived myocardial performance index (MPI), defined as the sum of isovolumetric contraction and relaxation durations divided by ejection time and reflecting both systolic and diastolic myocardial function, has been found to be related to morbidity and mortality in cardiac diseases. The MPI is easily obtained, reproducible, and has a narrow range in healthy subjects. The goal of this study

Steen H. Poulsen; Jens C. Nielsen; Henning R. Andersen

2000-01-01

33

Average heart rate, heart rate variability and the sympathovagal balance  

Microsoft Academic Search

Investigated are the responses of the average heart rate and of the balance between the 0.07-0.14 and 0.14-0.40-Hz components of the heart power spectrum to gravitational stress. This was done by taking finger blood pressure measurements in 18 young normals during two 1-hour sessions. In each session there were two supine-standing and two standing-supine transitions. For each transition the changes

Marc J. A. Janssen; Cees A. Swenne; Johan de Bie; Volkert Manger Cats; Albert V. G. Bruschke

1990-01-01

34

The effect of post-exercise hydrotherapy on subsequent exercise performance and heart rate variability.  

PubMed

We investigated the effect of hydrotherapy on time-trial performance and cardiac parasympathetic reactivation during recovery from intense training. On three occasions, 18 well-trained cyclists completed 60 min high-intensity cycling, followed 20 min later by one of three 10-min recovery interventions: passive rest (PAS), cold water immersion (CWI), or contrast water immersion (CWT). The cyclists then rested quietly for 160 min with R-R intervals and perceptions of recovery recorded every 30 min. Cardiac parasympathetic activity was evaluated using the natural logarithm of the square root of mean squared differences of successive R-R intervals (ln rMSSD). Finally, the cyclists completed a work-based cycling time trial. Effects were examined using magnitude-based inferences. Differences in time-trial performance between the three trials were trivial. Compared with PAS, general fatigue was very likely lower for CWI (difference [90% confidence limits; -12% (-18; -5)]) and CWT [-11% (-19; -2)]. Leg soreness was almost certainly lower following CWI [-22% (-30; -14)] and CWT [-27% (-37; -15)]. The change in mean ln rMSSD following the recovery interventions (ln rMSSD(Post-interv)) was almost certainly higher following CWI [16.0% (10.4; 23.2)] and very likely higher following CWT [12.5% (5.5; 20.0)] compared with PAS, and possibly higher following CWI [3.7% (-0.9; 8.4)] compared with CWT. The correlations between performance, ln rMSSD(Post-interv) and perceptions of recovery were unclear. A moderate correlation was observed between ln rMSSD(Post-interv) and leg soreness [r = -0.50 (-0.66; -0.29)]. Although the effects of CWI and CWT on performance were trivial, the beneficial effects on perceptions of recovery support the use of these recovery strategies. PMID:21710292

Stanley, Jamie; Buchheit, Martin; Peake, Jonathan M

2011-06-28

35

Heart Rate Slowing for Myocardial Dysfunction\\/Heart Failure  

Microsoft Academic Search

Heart failure is a major health problem, and is one of the few cardiovascular diseases that increased its prevalence over the last decade. Increased heart rate, generally observed in patients with heart failure, is involved in the deterioration of cardiac pump function. However, the effects of ’pure’ heart rate reduction on the progression of heart failure are unknown. In a

P. Mulder; C. Thuillez

2006-01-01

36

Instantaneous monitoring of heart rate variability  

Microsoft Academic Search

Most of the currently accepted approaches to compute heart rate and assess heart rate variability operate on interpolated, continuous-valued heart rate signals, thereby ignoring the underlying discrete structure of human heart beats. To overcome this limitation, we model the stochastic structure of heart beat intervals as a history-dependent, inverse Gaussian process and derive from it an explicit probability density describing

R. Barbieri; E. C. Matten; E. N. Brown

2003-01-01

37

Relationship of Hospital Performance with Readmission and Mortality Rates for Patients Hospitalized with Acute Myocardial Infarction, Heart Failure, or Pneumonia  

PubMed Central

Context The Centers for Medicare & Medicaid Services publicly reports hospital 30-day all-cause risk-standardized mortality rates (RSMRs) and 30-day all-cause risk-standardized readmission rates (RSRRs) for acute myocardial infarction (AMI), heart failure (HF), and pneumonia. The relationship between hospital performance as measured by RSMRs and RSRRs has not been well characterized. Objective We determined the relationship between hospital RSMRs and RSRRs overall, and within subgroups defined by hospital characteristics. Design, Setting, and Participants We studied Medicare fee-for-service beneficiaries discharged with AMI, HF, or pneumonia between July 1, 2005 and June 30, 2008. We quantified the correlation between hospital RSMRs and RSRRs using weighted linear correlation; evaluated correlations in groups defined by hospital characteristics; and determined the proportion of hospitals with better and worse performance on both measures. Main Outcome Measures Hospital 30-day RSMRs and RSRRs. Results The analyses included 4506 hospitals for AMI; 4767 hospitals for HF; and 4811 hospitals for pneumonia. The mean RSMRs and RSRRs were 16.60% and 19.94% for AMI; 11.17% and 24.56% for HF; and 11.64% and 18.22% for pneumonia. The correlations (95% confidence intervals [CIs]) between RSMRs and RSRRs were 0.03 (95% CI: ?0.002, 0.06) for AMI, ?0.17 (95% CI: ?0.20, ?0.14) for HF, and 0.002 (95% CI: ?0.03, 0.03) for pneumonia. The results were similar for subgroups defined by hospital characteristics. Although there was a significant negative linear relationship between RSMRs and RSRRs for HF, the shared variance between them was only 2.90% (r2 = 0.029). Conclusions Our findings do not support concerns that hospitals with lower RSMRs will necessarily have higher RSRRs. The rates are not associated for patients admitted with an AMI or pneumonia and only weakly associated, within a certain range, for patients admitted with HF.

Krumholz, Harlan M.; Lin, Zhenqiu; Keenan, Patricia S.; Chen, Jersey; Ross, Joseph S.; Drye, Elizabeth E.; Bernheim, Susannah M.; Wang, Yun; Bradley, Elizabeth H.; Han, Lein F.; Normand, Sharon-Lise T.

2013-01-01

38

Dimensional analysis of heart rate variability in heart transplant recipients  

SciTech Connect

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

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

1987-01-01

39

Relationship between Heart Rate Turbulence and Heart Rate Variability in Korean Adults with Structurally Normal Heart  

Microsoft Academic Search

Background and Objectives:Heart rate variability (HRV) illustrates the autonomic integration of the heart. Depressed HRV has been proven to be associated with an increased risk of cardiac death, whereas heart rate turbu- lence (HRT) is believed to reflect baroreflex sensitivity and it was recently introduced as another noninvasive tool for risk stratification. The aim of this study was to determine

Ji Ho Yoon; Jin Ho Kang; Byung Jin Kim; Bum Soo Kim

40

A double-blind study on the effects of piracetam upon perceptual and psychomotor performance at varied heart rates in patients treated with artificial pacemakers  

Microsoft Academic Search

Pacemaker-patients have previously been found to have significantly impaired performance in tests of critical flicker fusion (CFF), two-choice reaction time (RT) and vernier visual acuity (KVAT) when the heart rate is reduced from 70 to 45 beats\\/min in sitting position.

Krister Lagergren; Sten Levander

1974-01-01

41

Heart rate variability and familial amyloidosis  

Microsoft Academic Search

A 32-year-old man with family history of amyloidosis was admitted to the hospital because of orthostatic hypotension. An echocardiogram was suggestive for cardiac amyloidosis. Heart rate variability analysis, performed on 24-h Holter monitoring, showed markedly low values in both frequency and time domain, reflecting a severe autonomic nervous system dysfunction.

Sergio Morelli; Enrico Carmenini; Alessandro Sgreccia; Ada Francia

2002-01-01

42

Heart rate monitors: State of the art  

Microsoft Academic Search

Heart rate is a useful indicator of physiological adaptation and intensity of effort. Therefore, heart rate monitoring is an important component of cardiovascular fitness assessment and training programmes. The electrocardiogram (ECG) and Holter monitoring devices are accurate, but they are not appropriate for use in field settings due to cost, size and complexity of operation. Lightweight telemetric heart rate monitors

Raija M. T. Laukkanen; Paula K. Virtanen

1998-01-01

43

Analysis of nonlinear heart rate dynamics in cardiac arrhythmias  

Microsoft Academic Search

Summary   Analysis of heart rate dynamics by methods based on nonlinear dynamics has opened a new approach for studying the abnormalities\\u000a in heart rate behavior as a predictor of cardiac arrhythmias. Recent studies have shown that the new nonlinear measures, particularly\\u000a fractal analysis methods of heart rate dynamics, perform better than traditional analysis methods as a predictor of sudden\\u000a cardiac

T. H. Mäkikallio; M. P. Tulppo; T. Seppänen; H. V. Huikuri

2000-01-01

44

Performance enhancing genetic variants, oxygen uptake, heart rate, blood pressure and body mass index of elite high altitude mountaineers.  

PubMed

Aim: To analyse and compare the ACE (angiotensin-converting enzyme), ACTN3 (actinin-3) and AMPD1 (adenosine monophosphate deaminase 1) genetic variants, oxygen uptake (VO2max), heart rate (HR), blood pressure (BP) and body mass index (BMI) of elite high altitude mountaineers and average athletes. Methods: Elite Bulgarian alpinists (n = 5) and control group of athletes (n = 72) were recruited. VO2max was measured using a treadmill graded protocol. HR, BP and BMI were recorded. Genotyping was done by polymerase chain reaction (PCR) amplification followed by agarose gel electrophoresis. Chi2-test and Fisher's exact test were used for statistical analysis. Results: Alpinists showed significantly higher frequencies of 60% ACE I allele (p = 0.002), 50% ACTN3 X allele (p = 0.032) and 30% AMPD1 T allele (p = 0.003) compared to controls - 39%, 36%, 13%, respectively. ACE ID genotype prevalence and null DD genotype were observed in mountaineers. Higher absolute VO2max, but no differences in VO2max ml kg-1 min-1, HR, oxygen pulse, blood pressure and BMI were found. Conclusions: The ID genotype and higher frequencies of ACE I allele could contribute to successful high altitude ascents in mountaineers. The genetic make-up of the two mountaineers who made the summit of Mt Everest was distinctive, revealing ACE ID genotype, mutant ACTN3 XX and AMPD1 TT genotypes. PMID:24058088

Djarova, Trayana; Bardarev, D; Boyanov, D; Kaneva, R; Atanasov, P

2013-09-01

45

Alexithymia, depression and heart rate in candidates for cardiac surgery  

Microsoft Academic Search

Effects of psychological traits on heart rate (HR) and heart rate variability (HRV) were evaluated in patients awaiting cardiac surgery. Alexithymics demonstrated slowed HR, whereas high cognitive performance was associated with elevated HR in 2–3 days before surgery. Depression negatively correlated with HRV low frequency power. These data are consistent with previous findings of diverse moderate stress effects on HR regulation

Leo A. Bokeriia; Elena Z. Golukhova; Anna G. Polunina; Dmitry M. Davydov; Maria V. Kruglova

2008-01-01

46

Heart Rate Control Via Vagus Nerve Stimulation.  

PubMed

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

47

Pre-stimuli heart rate differences  

Microsoft Academic Search

In this paper the results of an exploratory experiment on heart rate pre-stimuli reactions are presented. The 4 basic colours (blue, green, red and yellow) were presented as full-screen images on the computer (presentation phase), for a period of 4 seconds each. During this phase the heart rate was measured at fix intervals of 1 second, for a total of

Antonella Vannini; Ulisse Di Corpo

48

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

PubMed

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

49

Heart to Heart: Using Heart Rate Telemetry to Meet Physical Education Outcomes.  

ERIC Educational Resources Information Center

|Presents a foundation for establishing measurable physical education outcomes, demonstrating how heart rate telemetry can help measure and achieve such outcomes. After explaining heart rate telemetry function, the article examines student and teacher outcomes that could be included in school physical education outcomes and achieved using heart

Deal, Tami Benham; Deal, Laurence O.

1995-01-01

50

Heart to Heart: Using Heart Rate Telemetry to Meet Physical Education Outcomes.  

ERIC Educational Resources Information Center

Presents a foundation for establishing measurable physical education outcomes, demonstrating how heart rate telemetry can help measure and achieve such outcomes. After explaining heart rate telemetry function, the article examines student and teacher outcomes that could be included in school physical education outcomes and achieved using heart

Deal, Tami Benham; Deal, Laurence O.

1995-01-01

51

Elevated heart rate in cardiovascular diseases: a target for treatment?  

PubMed

Heart rate is a major determinant of myocardial oxygen consumption and of cardiac work, and thus reduction of heart rate may represent an important strategy for the treatment of patients with a wide range of cardiac disorders. In addition, several experimental lines of research point to high heart rate as an important risk factor for atherosclerosis and, thus, pharmacologic heart rate reduction could prevent or retard the development of atherosclerotic plaques and increase survival. Today, in patients with acute or chronic coronary syndromes or with congestive heart failure, reducing heart rate is a generally accepted treatment modality. Up to now, no human study has been performed to demonstrate the efficacy and the risk-benefit ratio of cardiac slowing in patients without cardiac disorders. However, recent retrospective analyses of the INternational VErapamil-SR/trandolapril STudy and the Paris Prospective Study 1 provided promising results. Treatment of high heart rate in healthy subjects appears to be premature, but in clinical conditions such as hypertension or diabetes, the reduction of elevated heart rate appears a desirable additional goal of therapy. PMID:19615493

Palatini, Paolo

52

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

PubMed

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. PMID:23366214

Bolkhovsky, Jeffrey B; Scully, Christopher G; Chon, Ki H

2012-01-01

53

The Evoked Heart Rate Response During Sleep.  

National Technical Information Service (NTIS)

Heart rate responses evoked by a 3-sec auditory stimulus were averaged within stages of sleep for five subjects. Although there were some individual differences, the evoked HR response is generally diphasic, with the peak of the acceleratory component occ...

D. J. Hord A. Lubin L. C. Johnson

1966-01-01

54

Heart rate-based nighttime awakening detection.  

PubMed

Sleep fragmentation is a cause of impaired daytime performance. We have developed an algorithm for detection of nighttime awakenings based on heart rate. As much as 15 healthy normal sleepers, 23 +/- 3 years, participated in this study. The dataset contains 33 nights of polysomnographic (PSG) and electrocardiographic (ECG) measurements. After a habituation night, the subjects underwent a reference night without interventions, followed by some nights with interventions. These included noise, light, physical and cognitive interventions. Nighttime awakenings were subdivided in to awakenings (>15 s) and short awakenings (<15 s). The overall number of awakenings was 18.5 (+/-10.5) and short awakenings 13.2 (+/-10.5). The number of nighttime awakenings did not differ significantly between the reference and intervention nights; a repeated measures ANOVA resulted in a p value of 0.66 for awakenings and 0.57 for short awakenings. As much as 5 reference nights were used as training set, 28 as validation set. The algorithm detects the awakening periods with a sensitivity of 80.5% (confidence interval 77.9-82.9%). Heart rate is an adequate measure that allows for detection of nighttime awakenings and hence sleep quality. PMID:20094892

Bulckaert, Arnoud; Exadaktylos, Vasileios; De Bruyne, Guido; Haex, Bart; De Valck, Elke; Wuyts, Johan; Verbraecken, Johan; Berckmans, Daniel

2010-01-23

55

Heart Rate Variability Biofeedback for Major Depression  

Microsoft Academic Search

Heart rate variability for the treatment of major depression is a novel, alternative approach that can offer symptom reduction with minimal-to-no noxious side effects. The following material will illustrate some of the work being conducted at our laboratory to demonstrate the efficacy of heart rate variability. Namely, results will be presented regarding our published work on an initial open-label study

Maria Karavidas

56

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

PubMed

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. PMID:23476702

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

2013-02-11

57

Heart rate dynamics during three forms of meditation  

Microsoft Academic Search

Objective: This study was designed to quantify and compare the instantaneous heart rate dynamics and cardiopulmonary interactions during sequential performance of three meditation protocols with different breathing patterns. Background: We analyzed beat-to-beat heart rate and continuous breathing signals from 10 experienced meditators (4 females; 6 males; mean age 42 years; range 29–55 years) during three traditional interventions: relaxation response, breath

C.-K. Peng; Isaac C. Henry; Joseph E. Mietus; Jeffrey M. Hausdorff; Gurucharan Khalsa; Herbert Benson; Ary L. Goldberger

2004-01-01

58

Heart rate and heart rate variability in patients with frequent ventricular arrhythmias  

Microsoft Academic Search

The authors studied associations between heart rate and heart rate variability in 31 patients with frequent ventricular arrhythmias. For each patient, a 24-h Holter tape was analyzed. Tapes were divided into 5-min episodes. Per episode, they computed heart rate (HR), the fraction low-frequency power (LF), and the coefficient of variance (CV). For each patient, scatterplots were made of LF=f(HR), CV=f(HR),

Cees A. Swenne; M. J. A. Janssen; V. M. Cats

1992-01-01

59

What is the "normal" fetal heart rate?  

PubMed Central

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, Stephanie; Boulesteix, Anne-Laure; Lederer, Christian; Grunow, Stefani; Schiermeier, Sven; Hatzmann, Wolfgang; Schneider, Karl-Theodor M.

2013-01-01

60

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

PubMed

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

61

Reduced heart rate variability following repair of tetralogy of Fallot  

PubMed Central

OBJECTIVE—To examine autonomic function as assessed by heart rate variability in patients 10 or more years after repair of tetralogy of Fallot, and to relate this to cardiac structure, function, and electrocardiographic indices.?METHODS—Heart rate variability was measured by standard time domain techniques on a 24 hour Holter ECG in 28 patients, aged 12 to 34 years (mean 19.5), who had undergone repair of tetralogy of Fallot at least 10 years previously. Echocardiography was performed to assess left ventricular size and function, right ventricular size and pressure, and any proximal pulmonary arterial stenosis. Right ventricular function was evaluated by radionuclide scan. QRS duration, QT interval, and QT dispersion were measured on a standard 12 lead ECG. Measurements of heart rate variability were compared with values from 28 age matched healthy controls (mean age 19.9 years). Interrelations between variables were assessed using Pearson correlation coefficients and stepwise regression analysis.?RESULTS—Heart rate variability was reduced, compared with values for age matched normal controls, in 12 of the 28 patients. Reduced heart rate variability was associated with increased age, increased right ventricular size and pressure, and widening of the QRS complex.?CONCLUSIONS—Reduced heart rate variability is a feature following repair of tetralogy of Fallot. It is associated with increasing age, impaired right ventricular haemodynamics, and widening of the QRS complex. Under these circumstances, reduced heart rate variability may be a marker for deteriorating right ventricular function. Increased QRS duration has been identified as a risk factor for sudden death following repair of tetralogy of Fallot, and impaired cardiac autonomic control may be one of the mechanisms involved.???Keywords: tetralogy of Fallot; heart rate variability; right ventricular function; congenital heart disease

McLeod, K; Hillis, W; Houston, A; Wilson, N; Trainer, A; Neilson, J; Doig, W

1999-01-01

62

Match analysis and heart rate of futsal players during competition.  

PubMed

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. PMID:17899472

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

2008-01-01

63

Heart Rate Recovery: Validation and Methodologic Issues  

Microsoft Academic Search

OBJECTIVES The goal of this study was to validate the prognostic value of the drop in heart rate (HR) after exercise, compare it to other test responses, evaluate its diagnostic value and clarify some of the methodologic issues surrounding its use. BACKGROUND Studies have highlighted the value of a new prognostic feature of the treadmill test—rate of recovery of HR

Katerina Shetler; Rachel Marcus; Victor F. Froelicher; Shefali Vora; Damayanthi Kalisetti; Manish Prakash; Jonathan Myers

2001-01-01

64

Heart rate variability in the individual fetus.  

PubMed

The change in fetal heart rate and its variability (HRV) during the course of gestation has been documented by numerous studies. The overall drop in heart rate and increase in fetal HRV is associated with fetal growth in general and with the increase in neural integration in particular. The increased complexity of the demands on the cardiovascular system leads to more variation in the temporal course of the heart rate. Most studies that document and interpret these changes are based on data acquired in groups of fetuses. The aim of this work was to investigate HRV within single fetuses. We acquired 213 5min fetal magnetocardiograms in 11 fetuses during the second and third trimesters (at least 10 data sets per fetus, median 17). From the magnetocardiograms we determined the fetal RR interval time series and calculated the standard deviation (SDNN), root mean square of successive differences (RMSSD), approximate entropy (ApEn) and temporal asymmetry (Irrev). For each subject and HRV measure, we performed regression analysis with respect to gestational age, alone and in combination with RR interval. The coefficient of determination R(2) was used to estimate goodness-of-fit. The coefficient of quartile dispersion (CQD) was used to compare the regression parameters for each HRV measure. Overall, the HRV measures increased with age and RR interval. The consistency of the HRV measures within the individual fetuses was greater than in the data pooled over all fetuses. The individual R(2) for the model including age and RR interval was best for ApEn (.79, .59-.94; median, 90% CI), followed by RMSSD (.71, .25-.88), SDNN (.55, .18-.90) and Irrev (.16, .01-.39). These values, except for Irrev, were higher than those calculated over all 213 data sets (R(2)=.65, .63, .35, .28, respectively). The slopes of the regressions of each individual's data were most consistent over all subjects for ApEn, followed by RMSSD and SDNN and Irrev. Interindividually, the time domain measures showed discrepancies and the within-fetus courses were more consistent than the course over all fetuses. On the other hand, the course of ApEn during gestation was not only very consistent within each fetus but also very similar between most of subjects. Complexity measures such as ApEn may thus more consistently reflect prenatal developmental factors influencing cardiovascular regulation. PMID:23369622

Van Leeuwen, Peter; Cysarz, Dirk; Edelhäuser, Friedrich; Grönemeyer, Dietrich

2013-01-29

65

Changes in heart rate variability during fainting.  

PubMed

Studies of heart rate variability in people who faint may yield insights into normal physiologic mechanisms which probably are dynamic. These insights might be gained because fainting appears to be due to a breakdown of these mechanisms. Tilt table testing reliably induces fainting in patients with a history of fainting and can be used to study these mechanisms. During tilt tests ending in fainting heart rate changes markedly, with a loss of high-frequency components on power spectral analysis and a progressive slowing of overall sinus node discharge. These changes appear to be due to changes in efferent vagal nerve traffic. Several possible mechanisms of these changes in heart rate variability are discussed. PMID:12779923

Sheldon, Robert; Riff, Kenneth

1991-10-01

66

Heart Rate and Electrocardiography Monitoring in Mice  

PubMed Central

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

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

2011-01-01

67

Physiological state characterization by clustering heart rate, heart rate variability and movement activity information  

Microsoft Academic Search

The objective is to identify whether it is possible to discriminate between normal and abnormal physiological state based on heart rate (HR), heart rate variability (HRV) and movement activity information in subjects with cardiovascular complications. HR, HRV and movement information were obtained from cardiac patients over a period of 6 weeks using an ambulatory activity and single lead ECG monitor.

Niranjan Bidargaddi; Antti Sarela; Ilkka Korhonen

2008-01-01

68

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

PubMed

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

69

Periodic Limb Movements and Heart Rate Changes  

PubMed Central

Periodic limb movements (PLM) during sleep are believed to be under the control of the sympathetic nervous system and may cause interrupted sleep and daytime sleepiness. The present case highlights the close relationship between PLM and significant heart rate changes independent of the presence of arousals. Thus, in addition to the already known deleterious effect on sleep continuity, moderate-severe PLM may also affect cardiovascular health. Citation: Oksenberg A; Gadoth N. Periodic limb movements and heart rate changes. J Clin Sleep Med 2012;8(4):447-449.

Oksenberg, Arie; Gadoth, Natan

2012-01-01

70

LED indicator for heart rate monitoring system in sport application  

Microsoft Academic Search

This paper presents a current invention for monitoring the athletes' heart rate during training or exercise session. A bracelet with different color code of Light Emitting Diode (LED) is designed as a wrist heart rate monitor. This color-coding makes the heart rate easier to monitor and enabling the user to know their heart rate range at a certain moment. Our

N. H. Mahmood; N. Uyop; N. Zulkarnain; F. K. Che Harun; M. F. Kamarudin; A. Linoby

2011-01-01

71

Heart rate characteristics monitoring for neonatal sepsis  

Microsoft Academic Search

While heart rate variability has been measured in many clinical settings and has offered insights into how HR is controlled, rarely has it offered unique information that has led to changes in patient management. We review our experience in developing continuous HR characteristics monitoring to aid in the early diagnosis of sepsis in premature infants in the neonatal intensive care

J. Randall Moorman; Douglas E. Lake; M. Pamela Griffin

2006-01-01

72

Heart rate variability in brain death  

Microsoft Academic Search

The sensitivity and specificity of heart rate variability (HRV) in the corroboration of brain death diagnosis in patients with acute traumatic intracranial lesions was evaluated in 20 patients with clinical criteria of brain death, nine patients in deep coma (Glasgow scale

J. Freitas; J. Puig; A. P. Rocha; P. Lago; J. Teixeira; M. J. Carvalho; O. Costa; A. Falcão de Freitas

1996-01-01

73

Heart Rate Preceding Motility in Sleep.  

National Technical Information Service (NTIS)

Heart rate (HR) increases before movement in sleep have been attributed to vascular congestion resulting from maintenance of a constant body position for a long period of time. An alternative hypothesis is that movements during sleep may be regulated by s...

R. E. Townsend L. C. Johnson P. Naitoh A. G. Muzet

1975-01-01

74

Electrocardiographic pill for cattle heart rate determination  

Microsoft Academic Search

Decreased agricultural profit margins and recent bioterrorism concerns have led to an increased interest in monitoring livestock health. Heart rate and core body temperature are traditional vital parameters for cattle health assessment, as they provide warnings for illness and disease. However, obtaining these data in the field is time and labor intensive, which speaks to the need for solutions that

Steve Warren; Angel Martinez; Timothy Sobering; Daniel Andresen

2008-01-01

75

Increased heart rate variability during nondirective meditation  

Microsoft Academic Search

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

Anders Nesvold; Morten W Fagerland; Svend Davanger; Øyvind Ellingsen; Erik E Solberg; Are Holen; Knut Sevre; Dan Atar

2012-01-01

76

Toward quantitative fetal heart rate monitoring  

Microsoft Academic Search

Continuous electronic fetal heart rate (FHR) monitoring during labor is motivated by the clinical experience that fetal distress causes loss of FHR variation and the occurrence of decelerations late during uterine contraction. This practice is of uncertain clinical benefit, perhaps because the interpretation is qualitative. We have developed new quantitative measures and analyzed cardiotocograph records from 148 consecutive patients, 44

Hanqing Cao; Douglas E. Lake; James E. Ferguson; Christian A. Chisholm; M. Pamela Griffin; J. Randall Moorman

2006-01-01

77

Voluntary heart rate deceleration: A critical evaluation  

Microsoft Academic Search

This experiment was designed as a test of the view that the human heart rate (HR) deceleration response can be brought under voluntary control, when some form of exteroceptive feedback is available. Sixteen female volunteers were randomly assigned to two groups. The first group received instructions to decrease their HR plus a continuous negative (failure) binary feedback, while the second

Marc-André Bouchard; Jacques Labelle

1982-01-01

78

Age-related heart rate response to exercise in heart transplant recipients. Functional significance  

Microsoft Academic Search

The heart rate (HR) and O2 uptake ($\\\\mathop V\\\\limits^\\\\cdot O_2 $ ) responses to cycle ergometer exercise and the role of O2 transport in limiting submaximal and maximal aerobic performance were assessed in 33 heart transplant recipients (HTR) [14 children (P-HTR), 11 young adults (YA-HTR) and 8 middle-age adults (A-HTR)] and in 28 age-matched control subjects (CTL). In 7 P-HTR

Claudio Marconi; Mauro Marzorati; Roberto Fiocchi; Filippo Mamprin; Paolo Ferrazzi; Guido Ferretti; Paolo Cerretelli

2002-01-01

79

Gaussian Mixture Model of Heart Rate Variability  

PubMed Central

Heart rate variability (HRV) is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters.

Costa, Tommaso; Boccignone, Giuseppe; Ferraro, Mario

2012-01-01

80

Validity of a heart rate inflection point or a 3.2 kilometer performance pace as estimators of maximal steady?state running velocity in high school runners  

Microsoft Academic Search

Fifty?seven high school middle distance runners (39 male and 18 female athletes) were assessed for maximal steady?state (MSS) running velocity (RV), RV at a heart rate inflection point (HRi), and a competitive 3.2 km RV (RV3.2km) for the purpose of determining the correlation between actual MSS RV (MSS RVOBS) and that estimated from the Conconi and LaFontaine field test A

James Walker; Patricia Eisenman

1995-01-01

81

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

ERIC Educational Resources Information Center

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

Kirkpatrick, Beth; Birnbaum, Burton H.

82

Physiological control of intraaorta pump based on heart rate.  

PubMed

Because of the special structures of intraaorta pump, the pressure and blood flow sensors cannot be implanted in the blood pump. Moreover, the cardiovascular pump is a very complex system that has no accurate model but much uncertainty and disturbance. Hence, the conventional control algorithm cannot achieve good performance. To overcome this problem, on one hand, a cardiovascular pump model is established. The heart rate in this model is chosen as a controlled variable that is a nonlinear function of the mean arterial pressure. On the other hand, a fuzzy logic feedback control algorithm, which maintains the actual heart rate tracking the desired heart rate, is designed. Computer simulations are performed to verify the robustness and dynamic characters of the controller. The simulation results demonstrate that the controller can maintain the actual heart rate tracking the desired one without static error. When the desired heart rate changed from 100 to 80 bpm, the settling time is <10 seconds. When the peripheral resistance increases from 1.0 to 0.7 mm Hg/ml, the settling time is <10 seconds. PMID:21307771

Gao, Bin; Nie, Li Ya; Chang, Yu; Zeng, Yi

83

Investigation of determinism in heart rate variability.  

PubMed

The article searches for the possible presence of determinism in heart rate variability (HRV) signals by using a new approach based on NARMA (nonlinear autoregressive moving average) modeling and free-run prediction. Thirty-three 256-point HRV time series obtained from Wistar rats submitted to different autonomic blockade protocols are considered, and a collection of surrogate data sets are generated from each one of them. These surrogate sequences are assumed to be nondeterministic and therefore they may not be predictable. The original HRV time series and related surrogates are submitted to NARMA modeling and prediction. Special attention has been paid to the problem of stationarity. The results consistently show that the surrogate data sets cannot be predicted better than the trivial predictor-the mean-while most of the HRV control sequences are predictable to a certain degree. This suggests that the normal HRV signals have a deterministic signature. The HRV time series derived from the autonomic blockade segments of the experimental protocols do not show the same predictability performance, albeit the physiological interpretation is not obvious. These results have important implications to the methodology of HRV analysis, indicating that techniques from nonlinear dynamics and deterministic chaos may be applied to elicit more information about the autonomic modulation of the cardiovascular activity. (c) 2000 American Institute of Physics. PMID:12779396

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

2000-06-01

84

Heart rate chaos as a mortality predictor in mild to moderate heart failure.  

PubMed

Linear and nonlinear indices of heart rate variability (HRV) have been shown to predict mortality in congestive heart failure (CHF). However, most nonlinear indices describe only the fractality or complexity of HRV but not the intrinsic chaotic properties. In the present study, we performed linear (time- and frequency-domain), complexity (sample entropy), fractal (detrended fluctuation analysis) and chaos (numerical titration) analyses on the HRV of 50 CHF patients from the United Kingdom heart failure evaluation and assessment of risk trial database. Receiver operating characteristic and survival analysis yielded the chaos level to be the best predictor of mortality (followed by low/high frequency power ratio, LF/HF), such that these indices were significant in both univariate and multivariate models. These results indicate the power of heart rate chaos analysis as a potential prognostic tool for CHF. PMID:18003141

Arzeno, Natalia M; Kearney, Mark T; Eckberg, Dwain L; Nolan, James; Poon, Chi-Sang

2007-01-01

85

Vaginal Intercourse Frequency and Heart Rate Variability  

Microsoft Academic Search

We examined the relationship between recalled and diary recorded frequency of penile-vaginal intercourse (FSI) and both resting heart rate variability (HRV; an index of cardiac autonomic control and parasympathetic tone associated with cardiovascular health outcomes) and resting diastolic blood pressure (DBP) in 120 healthy adults aged 19-38 (subjects scoring above the 87th percentile on the Lie scale of the Eysenck

STUART BRODY; RAGNAR PREUT

2003-01-01

86

Heart rate variability and intima media thickness  

Microsoft Academic Search

Increased activity in the sympathetic nervous system is part of the physiological stress response and is expressed in the\\u000a heart rate variability (HRV). The objective of this study was to examine associations of HRV and intima media thickness (IMT).\\u000a In 2002, satisfactory measurements of HRV of 78 voluntary participants were made, both during a stress test and during sleep.\\u000a IMT

Nanna Hurwitz Eller; Birgitta Malmberg; Peter Bruhn

2006-01-01

87

Periodic limb movements and heart rate changes.  

PubMed

Periodic limb movements (PLM) during sleep are believed to be under the control of the sympathetic nervous system and may cause interrupted sleep and daytime sleepiness. The present case highlights the close relationship between PLM and significant heart rate changes independent of the presence of arousals. Thus, in addition to the already known deleterious effect on sleep continuity, moderate-severe PLM may also affect cardiovascular health. PMID:22893777

Oksenberg, Arie; Gadoth, Natan

2012-08-15

88

H 2 Blocker modulates heart rate variability  

Microsoft Academic Search

Summary  The use of H2-blockers in the treatment of patients with peptic ulcer has become popular. However, this treatment has adverse cardiovascular\\u000a effects. The aim of this study was to investigate proarrhythmic rhythm and autonomic nervous activity by analyzing heart rate\\u000a variability in patients treated with omeprazole, ranitidine, and plaunotol. Nineteen patients (mean age 67.5 ± 2.7 years)\\u000a with active gastric

Tatsuhiko Ooie; Tetsunori Saikawa; Masahide Hara; Hidenobu Ono; Masataka Seike; Toshiie Sakata

1999-01-01

89

Heart Rate Patterns in Fetal Anemia  

Microsoft Academic Search

Fetal heart rate (FHR) was monitored immediately before cordocentesis on 105 occasions in 49 red cell-isoimmunized patients at 27–37 weeks of gestation. The fetal hemoglobin concentration, oxygen tension and oxygen content were measured and the values related to the FHR patterns, which were classified as reactive, non-reactive, decelerative (isolated or repetitive), terminal or sinusoidal. In 88% of non-anemic fetuses the

G. Sadovsky; G. H. A. Visser; K. H. Nicolaides

1988-01-01

90

System to measure heart performance  

NASA Astrophysics Data System (ADS)

Systems to measure heart condition are applied to patients with early or chronic cardiac problems with the aim of diagnosing and exactly locat- ing the problem. Two very important factors exist that are taken into account in order to obtain a reliable diagnosis and to be able to give suitable medical treatment. One of them is the volume of blood that the heart pumps, the other is the temperature gradient. In our system we measure both parameters at the same time with the purpose of determining how the heart is working from the amount of blood pumped per unit time. (To be presented in Spanish.)

Andrade, Armando; Rios, Heriberto; Lizana, Pablo R.; Puente, Ernestina; Mendoza, Diego

2002-11-01

91

Autonomic control of heart rate during physical exercise and fractal dimension of heart rate variability.  

PubMed

The objectives of the present study were to investigate autonomic nervous system influence on heart rate during physical exercise and to examine the relationship between the fractal component in heart rate variability (HRV) and the system's response. Ten subjects performed incremental exercise on a cycle ergometer, consisting of a 5-min warm-up period followed by a ramp protocol, with work rate increasing at a rate of 2.0 W/min until exhaustion. During exercise, alveolar gas exchange, plasma norepinephrine (NE) and epinephrine (E) responses, and beat-to-beat HRV were monitored. HRV data were analyzed by "coarse-graining spectral analysis" (Y. Yamamoto and R. L. Hughson. J. Appl. Physiol. 71: 1143-1150, 1991) to break down their total power (Pt) into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low-frequency (0.0-0.15 Hz) and high-frequency (0.15-0.8 Hz) components, from which low-frequency and high-frequency power (Pl and Ph, respectively) were calculated. Parasympathetic (PNS) and sympathetic (SNS) nervous system activity indicators were evaluated by Ph/Pt and Pl/Ph, respectively. From the fractal component, the fractal dimension (DF) and the spectral exponent (beta) were calculated. The PNS indicator decreased significantly (P < 0.05) when exercise intensity exceeded 50% of peak oxygen uptake (VO2 peak). Conversely, the SNS indicator initially increased at 50-60% VO2peak (P < 0.05) and further increased significantly (P < 0.05) at > 60% VO2peak when there were also more pronounced increases in NE and E.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8458809

Nakamura, Y; Yamamoto, Y; Muraoka, I

1993-02-01

92

Reinnervation of the transplanted human heart as evidenced from heart rate variability studies  

Microsoft Academic Search

This study evaluated heart rate variability (HRV) after cardiac transplantation in humans in an attempt to test the hypothesis that cardiac reinnervation occurs in the post-transplant period. HRV was measured using 24-hour Holter recordings performed on 37 ambulant patients 1 to 122 months after cardiac transplantation. All patients were free of histologic rejection and were taking no medication likely to

Igor Halpert; A. David Goldberg; Arlene B. Levine; T. Barry Levine; Robert Kornberg; Colleen Kelly; Michael Lesch

1996-01-01

93

Decreased heart rate variability in amyotrophic lateral sclerosis.  

PubMed

Autoregressive spectral analysis of heart rate variability (HRV) was performed in 29 patients with amyotrophic lateral sclerosis (ALS) and 33 age-matched healthy subjects to evaluate the involvement of the autonomic nervous system. HRV analysis provides a means to recognize low (LF) and high (HF) frequency components, respectively mediated by sympathetic and parasympathetic heart control. An increase in the mean heart rate at rest (P < 0.001), a decrease in standard deviation of R-R interval as well as in PNN50 (P < 0.001), and an increase in the LF/HF component ratio (P < 0.01) were found in the ALS patients, indicating a vagal-sympathetic imbalance. These alterations were not related to the clinical features and to the duration of the disease. Our results suggest a subclinical involvement of the autonomic nervous system in ALS, particularly affecting parasympathetic cardiovascular control. PMID:7565918

Pisano, F; Miscio, G; Mazzuero, G; Lanfranchi, P; Colombo, R; Pinelli, P

1995-11-01

94

Squirrel monkey heart rate during formation of status orders  

Microsoft Academic Search

Determined the heart rate of 5 male squirrel monkeys by FM telemetry during the formation of status orders assessed with a full pair comparison design on 6 occasions over a 3-wk period. Heart rate was related to rank on the status order by a curvilinear function with the middle-ranking Ss showing the lowest heart rate during test sessions, but not

Douglas K. Candland

1970-01-01

95

Response of fetal heart rate to uterine contractions  

Microsoft Academic Search

The heart rate variability of fetuses under stress from maternal uterine contractions conveys critical information to clinicians and also provides theoretical clues about heart rate regulatory mechanisms. According to the polyvagal theory, the deceleration of fetal heart rate under stress is caused by the withdrawal of vagal tone. Recovery is mediated by its reestablishment. An implication of this mechanism is

N. S. Padhye; Z. Duan; M. T. Verklan

2004-01-01

96

A robust control design for heart rate tracking during exercise  

Microsoft Academic Search

In this study, a control design is proposed for the tracking control of heart rate response during treadmill exercise. The controller tracks an exerciser's heart rate to a given heart rate profile, that may represent a prescribed exercise protocol, by varying the speed of the treadmill. A guaranteed cost control approach is adopted in the control design so that the

Teddy M. Cheng; Andrey V. Savkin; Steven W. Su; Branko G. Celler; Lu Wang

2008-01-01

97

Catastrophe Theory Model for Decelerations of Fetal Heart Rate  

Microsoft Academic Search

Background: Decelerations of fetal heart rate (FHR) are the results of many pathophysiological factors that modulate the intrinsic rate of the heart. FHR change is a complex phenomenon and can be viewed as a type of nonlinear dynamic system. This paper presents a qualitative model of FHR decelerations based on catastrophe theory, especially to account for abrupt heart rate changes

Akihiko Kikuchi; Nobuya Unno; Tsuguhiro Horikoshi; Shiro Kozuma; Yuji Taketani

2006-01-01

98

Reproducibility of heart rate changes following adenosine infusion in man  

Microsoft Academic Search

The change in heart rate following infusion of adenosine in healthy human subjects was studied on two occasions. Adenosine produced a significant, dose-related increase in heart rate. Tachyphylaxis to this effect of the naturally occurring nucleoside did not occur. There was a tendency for prolonged infusion to cause a greater increase in heart rate, but this did not reach significance.

B. Clarke; T.-B. Conradson; C. M. S. Dixon; P. J. Barnes

1988-01-01

99

Evidence of transient heart rate change after smoking cessation  

Microsoft Academic Search

Heart rate slows immediately after smoking cessation but it is unclear whether this is a permanent or transient effect. Examining this issue may improve our understanding of nicotine withdrawal effects. A transient heart rate pattern would suggest that the cardiovascular system adapts chronically to nicotine and requires a period of adjustment to achieve a new homeostasis after cessation. Heart rate

Kenneth D. Ward; Arthur J. Garvey; Ryan E. Bliss

1992-01-01

100

Air Pollution and Heart Rate Variability  

PubMed Central

Background Outdoor air pollution and lead exposure can disturb cardiac autonomic function, but the effects of both these exposures together have not been studied. Methods We examined whether higher cumulative lead exposures, as measured by bone lead, modified cross-sectional associations between air pollution and heart rate variability among 384 elderly men from the Normative Aging Study. We used linear regression, controlling for clinical, demographic, and environmental covariates. Results We found graded, significant reductions in both high-frequency and low-frequency powers of heart rate variability in relation to ozone and sulfate across the quartiles of tibia lead. Interquartile range increases in ozone and sulfate were associated respectively, with 38% decrease (95% confidence interval = -54.6% to -14.9%) and 22% decrease (-40.4% to 1.6%) in high frequency, and 38% decrease (-51.9% to -20.4%) and 12% decrease (-28.6% to 9.3%) in low frequency, in the highest quartile of tibia lead after controlling for potential confounders. We observed similar but weaker effect modification by tibia lead adjusted for education and cumulative traffic (residuals of the regression of tibia lead on education and cumulative traffic). Patella lead modified only the ozone effect on heart rate variability. Conclusions People with long-term exposure to higher levels of lead may be more sensitive to cardiac autonomic dysfunction on high air pollution days. Efforts to understand how environmental exposures affect the health of an aging population should consider both current levels of pollution and history of lead exposure as susceptibility factors.

Park, Sung Kyun; O'Neill, Marie S.; Vokonas, Pantel S.; Sparrow, David; Wright, Robert O.; Coull, Brent; Nie, Huiling; Hu, Howard; Schwartz, Joel

2009-01-01

101

What's Normal? -- Temperature, Gender, and Heart Rate  

NSDL National Science Digital Library

This article, created by Allen L. Shoemaker of Calvin College, describes a dataset on body temperature, gender, and heart rate. The data is taken from a paper in the "Journal of the American Medical Association" that examined whether humans' true body temperature was 98.6 degrees. It addresses concepts like true means, confidence intervals, t-statistics, t-tests, the normal distribution, and regression. The author states that "it helps students to grasp concepts about true means, confidence intervals and t-statistics." This is a nice introduction into how statistics can be used in the medical field.

Shoemaker, Allen L.

2009-06-19

102

Vaginal intercourse frequency and heart rate variability.  

PubMed

We examined the relationship between recalled and diary recorded frequency of penile-vaginal intercourse (FSI) and both resting heart rate variability (HRV; an index of cardiac autonomic control and parasympathetic tone associated with cardiovascular health outcomes) and resting diastolic blood pressure (DBP) in 120 healthy adults aged 19-38 (subjects scoring above the 87th percentile on the Lie scale of the Eysenck Personality Inventory were excluded from analyses). As in a previous smaller study, greater HRV was associated with greater FSI (but not masturbation or non-coital sex with a partner) and rated importance of intercourse. There were no sex differences in the HRV-FSI relationship, and the relationship was not explained by including measures of Extraversion, Neuroticism, Depression, Trait Anxiety, or partnership satisfaction. However, the previously obtained negative association of FSI with DBP was not replicated. PMID:14504008

Brody, Stuart; Preut, Ragnar

103

Respostas de Freqüência Cardíaca, Consumo de Oxigênio e Sensação Subjetiva ao Esforço em um Exercício de Hidroginástica Executado por Mulheres em Diferentes Situações Com e Sem o Equipamento Aquafins ? Heart Rate, Oxygen Consumption and Rating of Perceived Exertion Responses in a Water Aerobic Exercise Performed by Women at Different Situations with and without the Aquafins Apparatus  

Microsoft Academic Search

Aquatic exercise sessions are becoming increasingly diversified due to the use of apparatus appropriate to aquatic environment. However, few studies analyzed the influence of the use of such apparatus in the car- diorespiratory responses. The purpose was to analyze the heart rate, oxygen consumption and the rating of perceived exertion of effort in women during an aquatic exercise performed in

Stephanie Santana Pinto; Cristine Lima Alberton; Paulo André; Luiz Fernando Martins Kruel; Porto Alegre

104

Heart rate changes during avoidance learning in dogs  

Microsoft Academic Search

Ten animals were first trained to avoid an intense shock, and then all Ss were run until the avoidance response extinguished. Heart rate responses measured on each trial  [showed] an increase [to the CS]  There was a relationship between the intensity of the heart rate response and the occurrence of the avoidance response during acquisition. Also skeletal activity and heart

A. H. Black

1959-01-01

105

Significance of reduction in heart rate in cardiovascular disease.  

PubMed

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

106

Heart rate variability and drawing impairment in hypoxemic COPD  

Microsoft Academic Search

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 performing normally or abnormally on individual neuropsychological tasks. Spearman’s rho was used

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

2009-01-01

107

Oxygen consumption during fire suppression: error of heart rate estimation  

Microsoft Academic Search

Ten male firefighters were tested on a treadmill to determine their heart rate (HR) × oxygen consumption ( [Vdot]O2) relationship. These men then performed a simulated fire suppression protocol during which HR and [Vdot]O2 were measured m simultaneously by a protable physiological monitoring system. Average [Vdot]O2 in the simulated setting was 31.0±7.0ml-kg?1-min at a HR of 176 ±9 bpm. This

M. SOTHMANN; K. SAUPE; P. RAVEN; J. PAWELCZYK; P. DAVIS; C. DOTSON; F. LANDY; M. SILIUNAS

1991-01-01

108

Heart rate and oxygen consumption relationship changes following intense training  

Microsoft Academic Search

Seven male competitive runners (maximal oxygen consumption [VO2max] 66.2 ± 3.6 mlkg?min) participated in an evaluation of the effect of intense training on the relationships between heart rate (HR), VO2, and running speed. To establish a baseline relationship, subjects twice performed four randomly ordered steady?state runs at a constant grade of 2.5%, and one maximal graded exercise test, following days

Russ S. Richardson; Stephen C. Johnson; James A. Walker

1992-01-01

109

Heart Rate Variability and Sustained Attention in ADHD Children  

Microsoft Academic Search

The major goal of the current study was to investigate the association between continuous performance tests (CPTs) and the heart rate variability (HRV) of attention deficit hyperactivity disorder (ADHD) children. The HRV, specifically the 0.10-Hz component, may be considered to be a psychophysiological index of effort allocation (motivation): The less effort the subject allocates, the greater the 0.10-Hz component. Results

Norbert Börger; Jaap van Der Meere; Arjen Ronner; Ed Alberts; Reint Geuze; Hans Bogte

1999-01-01

110

Music structure determines heart rate variability of singers.  

PubMed

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

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

2013-07-09

111

First trimester embryonic\\/fetal heart rate in normal pregnant women  

Microsoft Academic Search

Objective: To establish reference ranges for first trimester embryonic\\/fetal heart rate in normal pregnant women. Materials and methods: This was a cross-sectional study. We performed ultrasonogram in 319 normal pregnant women, gestation age between 6+0 and 14+6 weeks and measured embryonic\\/fetal heart rates using M-mode. The embryonic\\/fetal heart rates were analyzed according to gestational ages (GA). Results: Data of 319

Tharangrut Hanprasertpong; Vorapong Phupong

2006-01-01

112

Heart rate variability and its relation to ventricular arrhythmias in congestive heart failure.  

PubMed Central

BACKGROUND--It has been shown that heart rate variability is decreased in patients with congestive heart failure and that depressed heart rate variability is associated with a propensity to ventricular arrhythmias. Little is known, however, about heart rate variability in patients with both congestive heart failure and ventricular arrhythmias. METHODS--Spectral heart rate variability was analysed from 24 hour ambulatory electrocardiograms in 15 controls, 15 patients with non-sustained ventricular tachycardia associated with clinically normal hearts (NHVT group), and 40 patients with congestive heart failure (CHF group) secondary to either ischaemic heart disease (n = 15) or idiopathic dilated cardiomyopathy (n = 25). Of the 40 patients with congestive heart failure 15 had no appreciable ventricular arrhythmias (ventricular extrasystoles < 10 beats/h and no salvos) and formed the CHF-VA- group. Another 15 patients with congestive heart failure and non-sustained ventricular tachycardia formed the CHF-NSVT group. RESULTS--Heart rate variability was significantly lower in the CHF group than in controls (mean (SD) total frequency 23 (12) v 43 (13) ms; low frequency 12 (8) v 28 (9) ms; high frequency 8 (5) v 14 (7) ms; p < 0.001). The differences in heart rate variability between controls and the NHVT group, between ischaemic heart disease and dilated cardiomyopathy, and between the CHF-VA- and CHF-NSVT groups were not significant. In the CHF group heart rate variability was significantly related to left ventricular ejection fraction but not associated with ventricular arrhythmias. The frequency of ventricular extrasystoles was significantly related to the high frequency component of heart rate variability (r = 0.54, p < 0.05) in the NHVT group. Stepwise multiple regression analysis showed that in the CHF group, heart rate variability was predominantly related to left ventricular ejection fraction (p < 0.05). There was no significant difference in heart rate variability between survivors (n = 34) and those who died suddenly (n = 6) at one year of follow up in the CHF group. CONCLUSION--In patients with congestive heart failure, heart rate variability is significantly decreased. The depressed heart rate variability is principally related to the degree of left ventricular impairment and is independent of aetiology and the presence of ventricular arrhythmias. The data suggest that analysis of heart rate variability does not help the identification of patients with congestive heart failure at increased risk of sudden death.

Fei, L.; Keeling, P. J.; Gill, J. S.; Bashir, Y.; Statters, D. J.; Poloniecki, J.; McKenna, W. J.; Camm, A. J.

1994-01-01

113

Modeling ventricular contraction with heart rate changes  

Microsoft Academic Search

Recently, a mathematical model of the pumping heart has been proposed describing the heart as a pressure source depending on time, volume and flow. The underlying concept is based on a new two-step paradigm that allows separation between isovolumic (non-ejecting) and ejecting heart properties. The first step describes the ventricular pressure in the isovolumic ventricle. In the following step, the

J. T. Ottesen; M. Danielsen

2003-01-01

114

Contactless and unobtrusive measurement of heart rate in home environment.  

PubMed

Current technology trends, such as ubiquitous computing and calm technology, call for novel unobtrusive sensors. The commonly used heart rate monitoring techniques require direct contact to the patient which makes the patient well aware of the sensors. In this paper, a novel method for detecting the distance of an approaching patient and for measuring his or her heart rate with a microwave Doppler radar is presented. This enables a truly non-contact and unobtrusive measurement. In addition, the measurement can be performed even through thick clothing. Furthermore, the patient does not need to be aware of being monitored since the method enables measurement to be started automatically as the patient approaches the sensor. PMID:17946492

Zakrzewski, Mari; Kolinummi, Arto; Vanhala, Jukka

2006-01-01

115

To what extent does a given heart rate correlate with following heart rates in the developing human fetus?  

Microsoft Academic Search

To quantitatively determine the extent to which a given heart rate correlates with the following heart rate(s) at any gestational age, we studied 181 uncomplicated human fetuses between 23 and 41 weeks gestation. A continuous 90–120 min observation was made for each case using external Doppler-ultrasound cardiotocography. For every individual fetal heart rate dataset, ‘probability distribution matrices’ were calculated with

Masanobu Ogawa; Toshiyuki Yoshizato; Takeshi Takashima; Takashi Koyanagi; Takahiko Suzuki; Hitoo Nakano

1996-01-01

116

Particle Effects on Heart-Rate Regulation in Senescent Mice  

Microsoft Academic Search

Because epidemiology studies consistently identify the elderly at risk for air pollution-related morbidity and mortality, we developed a model of senescent-dependent susceptibility based on indices of physiological aging. In the current study, we hypothesized that heart-rate regulation during particulate matter (PM) exposure differs with senescence-dependent susceptibility owing to variation in autonomic nervous control. Heart rate (HR) and heart-rate variability (HRV)

Clarke G. Tankersley; Matthew Campen; Alexis Bierman; Susan E. Flanders; Karl W. Broman; Richard Rabold

2004-01-01

117

Relevance of heart rate as a risk factor in hypertension  

Microsoft Academic Search

Numerous studies have shown that resting heart rate is closely correlated with blood pressure and that it is prospectively\\u000a related to the development of hypertension. Moreover, there is mounting evidence to indicate that a high heart rate is associated\\u000a with increased cardiovascular morbidity and mortality. In this respect, heart rate can be considered both as a marker of risk\\u000a and

Paolo Palatini; Stevo Julius

1999-01-01

118

Characteristics of maternal heart rate patterns during labor and delivery  

Microsoft Academic Search

OBJECTIVE:To find patterns characteristic of maternal heart rates recorded by an electronic fetal monitor and compare them with concomitant fetal heart rate (FHR) patterns.METHODS:Maternal heart rates and FHRs during active labor and delivery were simultaneously recorded in 26 parturients with singleton pregnancies in vertex presentation. The FHRs were obtained by an external ultrasound transducer or via a spiral scalp electrode

Dan J Sherman; Eugenia Frenkel; Yaffa Kurzweil; Anna Padua; Shlomo Arieli; Murat Bahar

2002-01-01

119

Unconstrained Evaluation System for Heart Rate Using Ultrasonic Vibrograph  

NASA Astrophysics Data System (ADS)

Unconstrained health monitoring systems have received much considerable attention in medical applications, because such system can examine a subject without constraint. In this study, we propose a detection method based on a fuzzy logic for evaluating heart rate using our ultrasonic vibrograph. In the experiment for confirming heart rate, our method has been successfully used to detect the heart rates of four subjects, compared with a method using an electrocardiograph.

Nagamune, Kouki; Kobashi, Syoji; Kondo, Katsuya; Hata, Yutaka; Taniguchi, Kazuhiko; Sawayama, Toshiyuki

2004-05-01

120

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

PubMed

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. PMID:22124525

Lee, C Matthew; Mendoza, Albert

2011-11-29

121

Heart rate and rate of oxygen consumption during flight of the barnacle goose, Branta leucopsis  

Microsoft Academic Search

We report the first measurements of heart rate (fH) and the rate of oxygen consumption (V?O2) during flights from a species of bird larger than 500 g. V?O2was obtained from nine forward flapping flights of 8.9 min mean duration at a mean speed of 13.2 m s?1 performed by three barnacle geese of mean mass 1.68 kg. Mean V?O2was 332

P. J Butler; A. J Woakes; R. M Bevan; R Stephenson

2000-01-01

122

The effect of magnesium sulfate on fetal heart rate parameters: A randomized, placebo-controlled trial  

Microsoft Academic Search

Objective: We sought to determine the effect of magnesium sulfate on fetal heart rate baseline value, variability, and acceleration-deceleration pattern. Study Design: Normal, nonlaboring pregnant patients at >30 weeks’ gestation were recruited. Baseline fetal heart rate monitoring for 1 hour was performed. After an 800-kcal meal, patients were randomized to receive either an intravenous loading dose of 6 g of

Mordechai Hallak; Juan Martinez-Poyer; Michael L. Kruger; Sonia Hassan; Sean C. Blackwell; Yoram Sorokin

1999-01-01

123

Effect of Antidysrhythmic Drugs on the Heart Rate and Blood Pressure Response to Treadmill Exercise  

Microsoft Academic Search

The heart rate and blood pressure response to exercise are clinically important parameters evaluated during treadmill testing. These responses may be altered by cardiac drugs. We evaluated the effect of procainamide and disopyramide on the heart rate and blood pressure response to treadmill exercise in 9 healthy volunteers. Each subject performed one Bruce protocol treadmill test while on each of

Paul E. Fenster; Keith A. Comess; Christine Dahl Hanson

1982-01-01

124

Correlations of left ventricular diastolic parameters and heart rate: assessment through right ventricular pacing  

Microsoft Academic Search

This study evaluated the correlations between left ventricular (LV) diastolic parameters assessed by equilibrium radionuclide angiography (ERNA) and heart rate (HR) through right ventricular pacing. Twelve patients with a permanent right ventricular apex pacemaker were included. Serial ERNA studies were performed under 6 sets of pacing cycle length (heart rate=52, 62, 72, 82, 92, 104 beats\\/min) for each patient. The

Zuo-Xiang He; Jacques Darcourt; Jean Pierre Camous; José Benoliel; Octave Migneco; Françoise Bussière-Lapalus; Marcel Baudouy; Philippe Morand

1992-01-01

125

Heart rate differences between right and left unilateral electroconvulsive therapy.  

PubMed Central

Left and right unilateral electrode placements were alternately applied in electroconvulsive therapy given to 21 men with melancholia. Accompanying heart rate elevations were greater following right unilateral treatment than left unilateral, apparently because of longer persistence of peak rates. This is consistent with right cerebral hemisphere superiority in the control of heart rate activity in neurologically intact humans.

Swartz, C M; Abrams, R; Lane, R D; DuBois, M A; Srinivasaraghavan, J

1994-01-01

126

Heart Rate: Changes during Conditioned Suppression in Rats  

Microsoft Academic Search

Heart rate of rats was recorded in the Estes-Skinner conditioned emotional response situation. Response to the conditioned stimulus was a decrease in rate. The change in heart rate was conditioned more slowly than suppression of bar-pressing; it was of shorter duration and was more variable than suppression.

Leyla de Toledo; A. H. Black

1966-01-01

127

Heart rate variability in left ventricular dysfunction and heart failure: effects and implications of drug treatment.  

PubMed Central

OBJECTIVE--To review the importance of heart rate variability analysis in left ventricular dysfunction and heart failure and to assess the effects of drug treatment. In patients with left ventricular dysfunction or heart failure, a low heart rate variability is a strong predictor of a low probability of survival. Because drug treatment in these patients has rapidly changed over the past two decades, the effect of these drugs on heart rate variability needs special attention. DESIGN--A study of published reports to give an overview of heart rate variability in patients with left ventricular dysfunction or heart failure and how it is affected by drug treatment. RESULTS--Analysis of heart rate variability provides an easily obtained early marker for progression of disease. It seems to be more closely related to the degree of neurohumoral activation than to haemodynamic variables. Cardiovascular drugs may either stimulate or inhibit the degree of neurohumoral activation, and the effects of pharmacological intervention can be closely monitored with this method. CONCLUSIONS--The analysis of heart rate variability, including spectral analysis, is a novel non-invasive way to obtain potentially useful clinical information in patients with reduced left ventricular function. The effects of drug treatment on heart rate variability are in general consistent with their long-term effects in left ventricular dysfunction and heart failure.

Tuininga, Y S; van Veldhuisen, D J; Brouwer, J; Haaksma, J; Crijns, H J; Man in't Veld, A J; Lie, K I

1994-01-01

128

Impaired post exercise heart rate recovery in anabolic steroid users.  

PubMed

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

129

Sleep problems and heart rate variability over the working day.  

PubMed

The purpose of this study was to discover whether greater sleep problems are associated with reduced heart rate variability during working hours and at night, and to determine whether this association is in part mediated by experienced affective states. This study involved 199 working women with a mean age of 33.8years. Sleep problems were assessed with the Jenkins Sleep Problems Scale, and the Day Reconstruction Method was used to measure positive affect and stress on the evening before and during the working day. Heart rate variability was indexed by the mean square root of the successive standard difference in heart period. Disturbed sleep was inversely related to heart rate variability during the working day (P=0.022), independently of demographic and behavioural confounders. Additional adjustment for positive affect and stress did not lead to further reductions in the association between sleep problems and reduced heart rate variability over the work day. Sleep problems were not predictive of reduced night-time heart rate variability. This report extends the findings from experimental studies and clinical samples, and suggests that disturbed sleep might impair heart rate variability in real life settings, in particular during working hours. Reduced heart rate variability might be a potential pathway linking sleep problems with cardiovascular disease. Based on the current data there was little evidence that the inverse associations between sleep problems and heart rate variability were mediated by experienced affective states. PMID:22309485

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

2012-02-07

130

Predictors of abnormal heart rate recovery in patients with heart failure reduced and preserved ejection fraction.  

PubMed

BACKGROUND: Heart rate recovery (HRR) is becoming an important prognostic maker in heart failure (HF), but very little is known about the underlying mechanisms responsible for its clinical efficacy. Therefore, we examined echocardiographic and exercise (submaximal and maximal) characteristics to gain a better appreciation of HRR and factors responsible for the development of abnormal HRR in patients with both heart failure reduced ejection fraction (HFrEF) and heart failure preserved ejection fraction (HFpEF). METHODS: Cardiopulmonary exercise testing (CPX), a 6-minute walk test (6MWT), and resting 2D echocardiography were randomly performed in 240 HF patients (200 HFrEF, 40 HFpEF) after which HRR was measured. HRR was defined as the difference between heart rate at peak exercise and 1?minute following test termination. RESULTS: Bivariate correlation analyses found significant relationships among most CPX and 6MWT measurements with the highest correlations between 6MWT HRR and 6MWT peak HR (r?=?0.65; p?performance in patients with HFrEF and HFpEF. PMID:23335654

Cahalin, Lawrence P; Arena, Ross; Labate, Valentina; Bandera, Francesco; Guazzi, Marco

2013-03-11

131

Heart Rate and Cardiovascular Disease: An Alternative to Beta Blockers  

PubMed Central

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

132

The Circadian Clock Influences Heart Performance  

Microsoft Academic Search

Circadian clocks are believed to provide the selective advantage of anticipation, thus allowing organisms to respond efficiently to stimuli at the appropriate moment. Disrupted circadian rhythms have been found to affect a variety of basic physiological processes. However, the importance of the circadian clock in regulating heart performance remains undetermined. We hypothesized that the circadian clock plays a crucial role

Xi Wu; Zhiwei Liu; Guangsen Shi; Lijuan Xing; Xiaohan Wang; Xiwen Gu; Zhipeng Qu; Zhen Dong; Jing Xiong; Xiang Gao; Chenyu Zhang; Ying Xu

2011-01-01

133

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

ERIC Educational Resources Information Center

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

Buck, Marilyn M.

134

Heart rate variability in depressive and anxiety disorders  

Microsoft Academic Search

Loss of normal autonomic nervous system control of heart rate and rhythm is an important risk factor for adverse cardiovascular events. After myocardial infarction, reduction in beat-to-beat heart rate variability, a measure of cardiac autonomic innervation by the brain, is a strong predictor of death. With loss of vagal innervation, as is noted in patients with severe neuropathy and in

Jack M. Gorman; Richard P. Sloan

2000-01-01

135

Heart Rate Slowing versus Other Pharmacological Antianginal Strategies  

Microsoft Academic Search

Relieving the symptoms of angina and improving the quality of life and functional status are important objectives in the management of patients with chronic stable angina. A high heart rate induces or exacerbates myocardial ischemia and angina because it both increases oxygen demand and decreases myocardial perfusion. &Bgr;-Blockers are effective at reducing anginal symptoms largely by decreasing heart rate. Physician

A. Diaz; J. Tardif

2006-01-01

136

Heart Rate Variability as a Predictor of Speaking Anxiety  

Microsoft Academic Search

This study examines the relations among the perception of speaking anxiety and difficulties in emotion regulation with 2 measures of physiological activity: heart rate (HR) and heart rate variability (HRV). Results show significant changes in HR and state anxiety, but not HRV, among the 6 experimental conditions: quiet, reading in both sitting and standing positions, and speaking in both sitting

Valerie A. MacIntyre; Peter D. MacIntyre; Geoff Carre

2010-01-01

137

Accentuated antagonism in the control of human heart rate  

Microsoft Academic Search

Invasive animal models indicate that the accelerative effects of the sympathetic nervous system on heart rate are highly dependent on the background level of vagal activity. A noninvasive, parasympathetic chronotropic index (respiratory sinus arrhythmia) and a sympathetic chronotropic index (left ventricular ejection time) were used to evaluate autonomic control of human heart rate. A strong interaction, previously called accentuated antagonism,

Sebastian H. J. Uijtdehaage; Julian F. Thayer

2000-01-01

138

Heart Rate Recovery During a College Basketball Game.  

National Technical Information Service (NTIS)

It has been established by several investigators that heart rate is a good indicator of the energy expenditure for a given work task. Heart rate has also been shown to give quicker response to emotional involvement than do other measures of physiological ...

J. D. Ramsey M. M. Ayoub R. A. Dudek H. S. Edgar

1970-01-01

139

Hypertension, Heart Rate, Use of Antihypertensives, and Incident Prostate Cancer  

Microsoft Academic Search

PURPOSE: Recent studies have reported conflicting results on a possible relationship between hypertension, heart rate, and prostate cancer. A model has been developed suggesting that high blood pressure and high heart rate may both be markers for increased central sympathetic nervous activity, which may result in androgen-mediated stimulation of prostate cancer growth.METHODS: In this study we examined the associations between

Annette L Fitzpatrick; Janet R Daling; Curt D Furberg; Richard A Kronmal; Joel L Weissfeld

2001-01-01

140

A monitoring device for continuous analysis of heart rate variability  

Microsoft Academic Search

A computer based system for bedside investigation of the autonomic nervous system (ANS) using spectral analysis of heart rate variability (HRV) is described. Primary information, electrocardiogram (ECG) signal, is obtained from a classical cardiotachymeter which is the interface between the patient and the device. A special software has been designed to continuously acquire the ECG samples, build the heart rate

U. Shim; A. Kumarakrishnan; S. B. Cahn; T. Sleator

1997-01-01

141

Acute Effects of Noise on Blood Pressure and Heart Rate  

Microsoft Academic Search

The authors assessed the acute effects of exposure to noise on systolic and diastolic blood pressure, and heart rate, among 46 workers in a midwestern auto assembly plant. Workers wore ambulatory blood pressure monitors and personal noise dosimeters during one work shift. After adjustment for covariates of cardiovascular function, systolic and diastolic blood pressure, along with heart rate, were shown

Sally L. Lusk; Brenda Gillespie; Bonnie M. Hagerty; Rosemary A. Ziemba

2004-01-01

142

Exaggerated heart rate oscillations during two meditation techniques  

Microsoft Academic Search

We report extremely prominent heart rate oscillations associated with slow breathing during specific traditional forms of Chinese Chi and Kundalini Yoga meditation techniques in healthy young adults. We applied both spectral analysis and a novel analytic technique based on the Hilbert transform to quantify these heart rate dynamics. The amplitude of these oscillations during meditation was significantly greater than in

Herbert Benson; Ary L. Goldberger

143

Exaggerated heart rate oscillations during two meditation techniques  

Microsoft Academic Search

We report extremely prominent heart rate oscillations associated with slow breathing during specific traditional forms of Chinese Chi and Kundalini Yoga meditation techniques in healthy young adults. We applied both spectral analysis and a novel analytic technique based on the Hilbert transform to quantify these heart rate dynamics. The amplitude of these oscillations during meditation was significantly greater than in

C.-K Peng; Joseph E Mietus; Yanhui Liu; Gurucharan Khalsa; Pamela S Douglas; Herbert Benson; Ary L Goldberger

1999-01-01

144

Development of Heart Rate Circadian Rhythm in Chickens  

Microsoft Academic Search

In chick embryos, various instantaneous heart rate (IHR) fluctuations (e.g. HR variability, HR irregularities) have been found and developmental patterns of mean heart rate (MHR) have been elucidated. IHR changes have also measured in newly hatched and young chickens in order to investigate the developmental patterns of MHR and any potential diurnal HR rhythmicity such as a circadian rhythm. The

K. Moriya; R. Akiyama; E. M. Dzialowski; W. W. Burggren; H. Tazawa

2004-01-01

145

Inverse temperature acclimation of heart rate in hibernating land snails  

Microsoft Academic Search

The heart rates of quiescent land snailsHelix lucorum andH. aspersa were recorded by impedance pneumography over several days. When snails acclimated to warm, humid, long days were transferred in late autumn to cool, dry, short days, in order to permit hibernation inverse rotational acclimation occurred, so that heart rates at low temperatures were lowered. However, temperature dependence increased so that

Stuart E. R. Bailey; Maria Lazaridou-Dimitriadou

1991-01-01

146

Seasonal Variation in Heart Rate Response to Core Temperature Changes.  

National Technical Information Service (NTIS)

The heart rate of normal, intact, unrestrained, unanesthetized, adult male Rana pipiens was studied over a range of core temperatures (16-32C) throughout a 12-month period. During the summer, heart rate response to increasing temperature was linear with a...

L. C. Miller S. Mizell

1971-01-01

147

Behavioural correlation of heart rate changes in family dogs  

Microsoft Academic Search

Fourteen dogs (7 males and 7 females) were tested for their heart rate (HR) and heart rate variability (HRV) responses in different activities and environmental challenges while their movement was controlled. First, we wanted to compare the dogs’ cardiac responses in different body positions (lying, sitting and standing) and during slow walking to reveal their possible influence on HR and

Katalin Maros; Antal Dóka; Ádám Miklósi

2008-01-01

148

Playing a violent television game affects heart rate variability  

Microsoft Academic Search

Objective: To investigate how playing a violent\\/nonviolent television game during the evening affects sympathetic and parasympathetic reactions during and after playing as well as sleep quality during the night after playing. Subjects and Methods: In total, 19 boys, 12-15 years of age, played television games on two occasions in their homes and participated once without gaming. Heart rate, heart rate

Malena Ivarsson; Martin Anderson; Torbjörn Åkerstedt; Frank Lindblad

2009-01-01

149

Heart rate variability related to effort at work  

Microsoft Academic Search

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

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

2011-01-01

150

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

PubMed

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. PMID:23489468

Melero-Ferrer, Josep L; Sánchez-Lázaro, Ignacio J; Almenar-Bonet, Luis; Martínez-Dolz, Luis; Buendía-Fuentes, Francisco; Portolés-Sanz, Manuel; Rivera-Otero, Miguel; Salvador-Sanz, Antonio

2013-03-15

151

Nocturnal evolution of heart rate variability indices in sleep apnea.  

PubMed

Heart rate variability (HRV) is a valuable clinical tool in diagnosing multiple diseases. This paper presents the results of a spectral HRV analysis conducted with 46 patients. HRV indices for the whole night show differences among patients with severe and mild apnea, and healthy subjects. These differences also appear when performing the analysis over 5-min intervals, regarding apneas being present or not in the intervals. Differences were also observed when analyzing the HRV nocturnal evolution. Results are consistent with the hypothesis that cardiovascular risk remains constant for OSA patients while it increases towards the end of the night for healthy subjects. PMID:23084286

Lado, María J; Méndez, Arturo J; Rodríguez-Liñares, Leandro; Otero, Abraham; Vila, Xosé A

2012-10-16

152

Heart rate and heart rate variability in pregnant warmblood and Shetland mares as well as their fetuses  

Microsoft Academic Search

Heart rate (HR) is an important parameter of fetal well-being. In horses, HR and heart rate variability (HRV) can be determined by fetomaternal electrocardiography (ECG) from mid-pregnancy to foaling. Normal values for physiological parameters in larger breeds are often used as reference values in ponies. However, HR increases with decreasing size of the animal and in ponies is higher than

Christina Nagel; Jörg Aurich; Franziska Palm; Christine Aurich

2011-01-01

153

Linear and nonlinear heart rate variability risk stratification in heart failure patients  

Microsoft Academic Search

Chronic heart failure (CHF) is a major and growing public health concern (~23 million people worldwide) with five-year survival rates of 25% in men and 38% in women. Objective of this study was to investigate whether linear and nonlinear heart rate variability (HRV) indices enhance risk prediction in patients with CHF. To discriminate between low risk (stable condition, N =

A. Voss; R. Schroeder; M. Vallverdu; I. Cygankiewicz; R. Vazquez; A. Bayes de Luna; P. Caminal

2008-01-01

154

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

ERIC Educational Resources Information Center

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

Ackerly, Spafford C.

2001-01-01

155

Performance Ratings and Librarians Rights  

ERIC Educational Resources Information Center

|Two aspects of rating personnel performance are explored: (1) the rating form and some guidelines for filling it in and (2) the right of the librarian who is being rated to discuss or appeal a rating he believes to be biased. (NH)|

Peele, David

1970-01-01

156

Study of Heart Rate Changes in Different Salat’s Positions  

Microsoft Academic Search

This paper describes the changes in the heart rate (HR) for 24 healthy subjects (10 males and 14 females) during performing\\u000a different Salat’s positions. Salat is the muslim prayer which involve performing certain physical postures as well as spiritual act. Heart rate was measured\\u000a using Schiller AT-102 augmented Electrocardiogram (ECG) at each of the following Salat’s positions: standing (qiyyam), bowing

Fatimah Ibrahim; W. A. Wan Ahmad

157

[Association between level of intelligence and heart rate variability].  

PubMed

Earlier we discovered that heart rate variability was associated with the level of intelligence. The purpose of this study is to confirm this association using more reliable method and to define more precisely the frequency band within which the amplitude of the heart rate modulations is related to intelligence. 13 males (aged 14 to 17) were the study subjects. The total score of the computer game Tetris was taken as a general measure of the intelligence level. Heart rate was recorded electrocardiographically both at rest and during playing Tetris. Frequency analysis of heart rate was carried out with digital Fourier transformation. Correlation analysis showed that there was positive association between the level of intelligence and the amplitude of heart rate modulation at the frequencies 0.30 and 0.15 modulations per RR interval. This association is closer for the heart rate at rest than for the heart rate during mental work and for the frequency 0.30 than for the 0.15 modulations per RR interval. PMID:21961308

Mukhin, V N; Iakovlev, N M

2011-08-01

158

Omega-3 Polyunsaturated Fatty Acids and Heart Rate Variability  

PubMed Central

Omega-3 polyunsaturated fatty acids (PUFA) may modulate autonomic control of the heart because omega-3 PUFA is abundant in the brain and other nervous tissue as well as in cardiac tissue. This might partly explain why omega-3 PUFA offer some protection against sudden cardiac death (SCD). The autonomic nervous system is involved in the pathogenesis of SCD. Heart rate variability (HRV) can be used as a non-invasive marker of cardiac autonomic control and a low HRV is a predictor for SCD and arrhythmic events. Studies on HRV and omega-3 PUFA have been performed in several populations such as patients with ischemic heart disease, patients with diabetes mellitus, patients with chronic renal failure, and in healthy subjects as well as in children. The studies have demonstrated a positive association between cellular content of omega-3 PUFA and HRV and supplementation with omega-3 PUFA seems to increase HRV which could be a possible explanation for decreased risk of arrhythmic events and SCD sometimes observed after omega-3 PUFA supplementation. However, the results are not consistent and further research is needed.

Christensen, Jeppe Hagstrup

2011-01-01

159

Changes in Respiratory Rate, Blood Pressure and Heart Rate Variability in Rabbits during Orthostasis  

Microsoft Academic Search

Mokr? J, T. RemeÀová, K. Javorka: Changes in Respiratory Rate, Blood Pressure and Heart Rate Variability in Rabbits during Orthostasis. Acta Vet. Brno 2006, 75: 3-12. The purpose of the study was to evaluate the changes of respiratory rate, systemic blood pressure and heart rate variability parameters (HRV) during orthostasis in anaesthetized rabbits. Furthermore, these changes were influenced by affecting

J. Mokrý; T. Reme?ová; K. Javorka

2006-01-01

160

Real-time Continuous Assessment Method for Mental and Physiological Condition using Heart Rate Variability  

NASA Astrophysics Data System (ADS)

It is necessary to monitor the daily health condition for preventing stress syndrome. In this study, it was proposed the method assessing the mental and physiological condition, such as the work stress or the relaxation, using heart rate variability at real time and continuously. The instantanuous heart rate (HR), and the ratio of the number of extreme points (NEP) and the number of heart beats were calculated for assessing mental and physiological condition. In this method, 20 beats heart rate were used to calculate these indexes. These were calculated in one beat interval. Three conditions, which are sitting rest, performing mental arithmetic and watching relaxation movie, were assessed using our proposed algorithm. The assessment accuracies were 71.9% and 55.8%, when performing mental arithmetic and watching relaxation movie respectively. In this method, the mental and physiological condition was assessed using only 20 regressive heart beats, so this method is considered as the real time assessment method.

Yoshida, Yutaka; Yokoyama, Kiyoko; Ishii, Naohiro

161

Scaling Behaviour and Memory in Heart Rate of Healthy Human  

NASA Astrophysics Data System (ADS)

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

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

2007-10-01

162

Long-range dependencies in heart rate signals—revisited  

Microsoft Academic Search

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

Danuta Makowiec; Aleksandra Dudkowska; Andrzej Rynkiewicz; Marcin Zwierz

2006-01-01

163

Circadian Rhythms of Spectral Components of Heart Rate Variability  

Microsoft Academic Search

Circadian rhythms of heart rate variability have been widely studied in recent years. However, most previous reports described such rhythms in terms of normalized units of the low- and high-frequency (LF and HF) spectral components. In this study, we analyzed circadian rhythms of spectral components in absolute units and found unexpected results in normal subjects as well as coronary heart

G. Q. Wu; L. L. Shen; D. K. Tang; D. A. Zheng; C.-S. Poon

2006-01-01

164

Screening of heart diseases with multivariate short-term heart rate variability analysis  

Microsoft Academic Search

\\u000a Heart diseases are the leading cause of mortality in the western world. The aim of this pilot study was to examine the possibility\\u000a of screening heart diseases for the general practitioner by short-term analysis (five-minute ECG segments) of the heart rate\\u000a variability (HRV) applying linear (time domain and frequency domain) and nonlinear (detrended fluctuation analysis (DFA),\\u000a compression entropy (CE), symbolic

A. Heitmann; T. Huebner; R. Schroeder; S. Perz; A. Voss

165

Predictive power of increased heart rate versus depressed left ventricular ejection fraction and heart rate variability for risk stratification after myocardial infarction  

Microsoft Academic Search

Objectives. The aim of this study was to compare the predictive value of mean RR interval assessed from predischarge Holter recordings with that of heart rate variability and left ventricular ejection fraction for risk stratification after myocardial infarction.Background. Heart rate variability is a powerful tool for risk stratification after myocardial infarction. Although heart rate variability is related to heart rate,

Xavier Copie; Katerina Hnatkova; Anne Staunton; Lü Fei; A. John Camm; Marek Malik

1996-01-01

166

Models for Handling Uncertainty Fetal Heart Rate and ECG Analysis.  

National Technical Information Service (NTIS)

Methods for handling imprecision and uncertainty in computer-based analysis of fetal heart rate patterns and ECG wave shape during childbirth are presented. Computational intelligence models, based on fuzzy logic techniques, that explicitly handle the imp...

E. C. Ifeachor J. S. Curnow N. J. Outram J. F. Skinner

2001-01-01

167

Method of Discriminant Gravity Tolerance using Heart Rate Variability  

NASA Astrophysics Data System (ADS)

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

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

168

Heart rate and body temperature as indices of metabolic rate during work  

Microsoft Academic Search

Summary  The possibility of using heart rate and body temperature as indices of metabolic rate during work has been investigated. Pulse determinations can advantageously be used at work of short duration whereas body temperature determinations can be useful for work of long dunation. These methods have to be used with great care due to the fact that both heart rate and

G. Berggren; E. Hohwü Christensen

1950-01-01

169

Heart rate monitoring and control in altered gravity conditions.  

PubMed

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. PMID:18003559

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

2007-01-01

170

VAGAL INFLUENCE ON HEART RATE IN HIBERNATING GROUND SQUIRRELS  

Microsoft Academic Search

Summary The heart rate of anesthetized golden mantled ground squirrels ( Spermophilus lateralis) falls from 372±20 to 37±9beatsmin 21 during hibernation at 7?C body temperature. Heart rate in the hibernating animals often waxed and waned in a fashion that was not clearly linked to the breathing pattern. Similar observations have been made on unanesthetized ground squirrels. Under anesthesia, the effects

WILLIAM K. MILSOM; ROY F. BURLINGTON

171

Drop in heart rate following smoking cessation may be permanent  

Microsoft Academic Search

Data are reported on the heart rates of nine smokers who underwent 5 weeks of abstinence. There was an initial fall of 9.1 beats per min from 79 to 69.9 beats per min on the 1st day, with no significant change thereafter. The average heart rates after 2, 3, 4 and 5 weeks were 69.1, 69.1, 71.7 and 69.9 beats

Nina Schneider

1988-01-01

172

Heart Rate and Blood Pressure Variability: Implications for Psychiatric Research  

Microsoft Academic Search

Symptoms of anxiety suggest autonomic dysfunction and most of the psycho-tropic agents used to treat anxiety and affective disorders have strong autonomic effects. This article describes the utility and importance of analysis of heart rate and blood pressure time series to study cardiac autonomic function in psychiatric research. The variability of heart rate between 0.15 and 0.5 Hz is related

Vikram K. Yeragani

1995-01-01

173

Age and Heart Rate Variability After Soccer Games  

Microsoft Academic Search

To observe the effect of age on the changes in heart rate variability (HRV) of adult amateur athletes after playing a soccer game, 20 male were divided into two groups: middle-aged (n = 10, 35–55 years) and aged (n = 10, 56–75 years). Before and after 2-hour soccer games, HRV and blood pressure were recorded. In both groups heart rate

Shuchun Yu; Takasumi Katoh; Hiroshi Makino; Soichiro Mimuno; Shigehito Sato

2010-01-01

174

Assessment of anxiety using heart rate nonlinear dynamics  

NASA Astrophysics Data System (ADS)

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

Thayer, Julian F.; Friedman, Bruce H.

1993-11-01

175

Complex demodulation of heart rate changes during orthostatic testing  

Microsoft Academic Search

Heart rate changes induced by the standing up of young healthy subjects are processed by a complex demodulation algorithm yielding time-local estimates of the amplitude of the heart-rate variability function. Complex demodulate of the high-frequency band (0.15 to 0.45 Hz) shows an abrupt decrease of amplitude immediately after standing up, presumably due into vagal withdrawal. Complex demodulation of a part

T. Kiauta; F. Jager; W. N. Tapp

1990-01-01

176

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

PubMed

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

177

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

NASA Astrophysics Data System (ADS)

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

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

2009-07-01

178

Major depression, heart rate, and plasma norepinephrine in patients with coronary heart disease  

Microsoft Academic Search

Background: Although it is now well established that psychiatric depression is associated with adverse outcomes in patients with coronary heart disease (CHD), the mechanism underlying this association is unclear. Elevated heart rate (HR) and plasma norepinephrine (NE), possibly reflecting altered autonomic nervous system activity, have been documented in medically well depressed psychiatric patients, and this pattern is associated with increased

Robert M Carney; Kenneth E Freedland; Richard C Veith; Philip E Cryer; Judith A Skala; Tiffany Lynch; Allan S Jaffe

1999-01-01

179

Magnesium administration may improve heart rate variability in patients with heart failure  

Microsoft Academic Search

Background and aimIntracellular magnesium (icMg) depletion may coexist with normomagnesemia. Mg deficiency (serum and\\/or intracellular) and decreased heart rate variability (HRV) are common in heart failure (HF). Since both are predictors of poor prognosis, it was of interest to evaluate the effect of Mg supplementation on HRV in patients with HF.

D. Almoznino-Sarafian; G. Sarafian; S. Berman; M. Shteinshnaider; I. Tzur; N. Cohen; O. Gorelik

2009-01-01

180

Matter Over Mind: A Randomised-Controlled Trial of Single-Session Biofeedback Training on Performance Anxiety and Heart Rate Variability in Musicians  

PubMed Central

Background Musical performance is a skilled activity performed under intense pressure, thus is often a profound source of anxiety. In other contexts, anxiety and its concomitant symptoms of sympathetic nervous system arousal have been successfully ameliorated with HRV biofeedback (HRV BF), a technique involving slow breathing which augments autonomic and emotional regulatory capacity. Objective: This randomised-controlled study explored the impact of a single 30-minute session of HRV BF on anxiety in response to a highly stressful music performance. Methods A total of 46 trained musicians participated in this study and were randomly allocated to a slow breathing with or without biofeedback or no-treatment control group. A 3 Group×2 Time mixed experimental design was employed to compare the effect of group before and after intervention on performance anxiety (STAI-S) and frequency domain measures of HRV. Results Slow breathing groups (n?=?30) showed significantly greater improvements in high frequency (HF) and LF/HF ratio measures of HRV relative to control (n?=?15) during 5 minute recordings of performance anticipation following the intervention (effect size: ?2?=?0.122 and ?2?=?0.116, respectively). The addition of biofeedback to a slow breathing protocol did not produce differential results. While intervention groups did not exhibit an overall reduction in self-reported anxiety, participants with high baseline anxiety who received the intervention (n?=?15) displayed greater reductions in self-reported state anxiety relative to those in the control condition (n?=?7) (r?=?0.379). Conclusions These findings indicate that a single session of slow breathing, regardless of biofeedback, is sufficient for controlling physiological arousal in anticipation of psychosocial stress associated with music performance and that slow breathing is particularly helpful for musicians with high levels of anxiety. Future research is needed to further examine the effects of HRV BF as a low-cost, non-pharmacological treatment for music performance anxiety.

Wells, Ruth; Outhred, Tim; Heathers, James A. J.; Quintana, Daniel S.; Kemp, Andrew H.

2012-01-01

181

Stretching increases heart rate variability in healthy athletes complaining about limited muscular flexibility  

Microsoft Academic Search

An increase in muscular flexibility, as well as a significant beneficial effect on heart rate and heart rate variability (HRV), was observed in healthy male athletes after performing a standardized 15-minute stretching-program over a period of 28 days. We believe the HRV increase to be due, at least in part, to the improved vagal and\\/or diminished sympathetic control. Therefore, we

Michael Mueck-Weymann; G. Janshoff; H. Mueck

2004-01-01

182

The relationship between anaerobic threshold and heart rate linearity during cycle ergometry  

Microsoft Academic Search

Summary  Recent studies have demonstrated there is a definitive deflection in the heart rate response to incremental velocity work\\u000a that coincides with the anaerobic threshold. These studies were conducted with elite athletes who performed the specific activities\\u000a in which they were trained. The purpose of this study was to determine if the same relationship in heart rate and ventilatory\\u000a response to

K. T. Francis; P. R. McClatchey; J. R. Sumsion; D. E. Hansen

1989-01-01

183

Developmental Change in Feedback Processing as Reflected by Phasic Heart Rate Changes  

Microsoft Academic Search

Heart rate was recorded from 3 age groups (8–10, 12, and 20–26 years) while they performed a probabilistic learning task. Stimuli had to be sorted by pressing a left versus right key, followed by positive or negative feedback. Adult heart rate slowed following negative feedback when stimuli were consistently mapped onto the left or right key (response-dependent condition) but not

Eveline A. Crone; J. Richard Jennings; Maurits W. Van der Molen

2004-01-01

184

Lactic acidosis, potassium, and the heart rate deflection point in professional road cyclists  

Microsoft Academic Search

Objective: To determine the influence of lactic acidosis, the Bohr effect, and exercise induced hyperkalaemia on the occurrence of the heart rate deflection point (HRDP) in elite (professional) cyclists.Methods: Sixteen professional male road cyclists (mean (SD) age 26 (1) years) performed a ramp test on a cycle ergometer (workload increases of 5 W\\/12 s, averaging 25 W\\/min). Heart rate (HR),

A Luci?a; J Hoyos; A Santalla; M Pe?rez; A Carvajal; J L Chicharro

2002-01-01

185

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

PubMed

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

186

Autonomic control of heart rate during exercise studied by heart rate variability spectral analysis.  

PubMed

Spectral analysis of heart rate variability (HRV) might provide an index of relative sympathetic (SNS) and parasympathetic nervous system (PNS) activity during exercise. Eight subjects completed six 17-min submaximal exercise tests and one resting measurement in the upright sitting position. During submaximal tests, work rate (WR) was increased for the initial 3 min in a ramp fashion until it reached constant WRs of 20 W, or 30, 60, 90, 100, and 110% of the predetermined ventilatory threshold (Tvent). Ventilatory profile and alveolar gas exchange were monitored breath by breath, and beat-to-beat HRV was measured as R-R intervals of an electrocardiogram. Spectral analysis was applied to the HRV from 7 to 17 min. Low-frequency (0-0.15 Hz) and high-frequency (0.15-1.0 Hz) areas under power spectra (LO and HI, respectively) were calculated. The indicator of PNS activity (HI) decreased dramatically (P less than 0.05) when the subjects exercised compared with rest and continued to decrease until the intensity reached 60% Tvent. The indicator of SNS activity (LO/HI) remained unchanged up to 100% Tvent, whereas it increased abruptly (P less than 0.05) at 110% Tvent. The results suggested that (cardiac) PNS activity decreased progressively from rest to a WR equivalent to 60% Tvent, and SNS activity increased only when exercise intensity exceeded Tvent. PMID:1757310

Yamamoto, Y; Hughson, R L; Peterson, J C

1991-09-01

187

A plausible explanation for heart rates in mammals.  

PubMed

We consider a simple model to give a plausible mechanical explanation of what are the actual resting heart rates of mammals optimized for. We study what is the optimal frequency for a viscoelastic fluid circulating in a pulsatile way through a network of tubes and conclude that the heart rate is not optimized to transport blood through the whole net. Rather, actual resting heart rates of mammals happen at frequencies that optimize flow in vessels of radii that correspond to large arteries, which bring oxygenated blood rapidly far away from the heart, towards head and limbs. Our results for the optimal frequencies, obtained using observed radii of femoral arteries in mammals, agree best with the heart rates observed. We find a theoretical allometric relation between optimal flow frequency and radius: nu approximately R(-1). This one, agrees with the exponent obtained when plotting observed heart rates versus radii of both, femoral arteries and carotids in mammals of different sizes, from mice to horses. PMID:20665970

Flores, J; Corvera Poiré, E; del Rio, J A; López de Haro, M

2010-08-21

188

A plausible explanation for heart rates in mammals.  

PubMed

We consider a simple model to give a plausible mechanical explanation of what are the actual resting heart rates of mammals optimized for. We study what is the optimal frequency for a viscoelastic fluid circulating in a pulsatile way through a network of tubes and conclude that the heart rate is not optimized to transport blood through the whole net. Rather, actual resting heart rates of mammals happen at frequencies that optimize flow in vessels of radii that correspond to large arteries, which bring oxygenated blood rapidly far away from the heart, towards head and limbs. Our results for the optimal frequencies, obtained using observed radii of femoral arteries in mammals, agree best with the heart rates observed. We find a theoretical allometric relation between optimal flow frequency and radius: nu approximately R(-1). This one, agrees with the exponent obtained when plotting observed heart rates versus radii of both, femoral arteries and carotids in mammals of different sizes, from mice to horses. PMID:20685604

Flores, J; Corvera Poiré, E; Del Río, J A; López de Haro, M

2010-06-01

189

Natural killer cell and proinflammatory cytokine responses to mental stress: associations with heart rate and heart rate variability  

Microsoft Academic Search

Associations between natural killer (NK) cell, proinflammatory cytokine stress responsivity, and cardiac autonomic responses (indexed by heart rate and heart rate variability) were assessed in 211 middle-aged men and women. Blood was drawn at baseline, immediately following color–word interference and mirror tracing tasks for the assessment of NK cell numbers, and 45 min post-stress for assessing plasma interleukin 6 (IL-6)

Natalie Owen; Andrew Steptoe

2003-01-01

190

Child's Heart Beat: Developmental Changes in Heart Rate and Attention during Middle Childhood.  

National Technical Information Service (NTIS)

The main goal of the thesis is to document developmental changes in heart rate responsitivity and attention during the middle childhood period. The thesis consists of two parts--a methodological and an empirical part. The methodological part concerns the ...

E. J. M. Weber

1993-01-01

191

Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots  

NASA Astrophysics Data System (ADS)

Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced `modified' Sensitivity (SE°) and `modified' Positive Predictive Value (PPV°) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

Georgieva, A. E.; Payne, S. J.; Moulden, M.; Redman, C. W. G.

2010-10-01

192

Heart rate variability and target organ damage in hypertensive patients  

PubMed Central

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?heart were found in patients with plaque compared to those with a normal IMT (p-value <0.05). These associations remained significant after adjustment for other factors known to contribute to the development of target organ damage, such as age. Moreover, depressed LF/HF was found also in patients with left ventricular hypertrophy but this association was not significant after adjustment for other factors. 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.

2012-01-01

193

Transfer of heart rate feedback training to reduce heart rate response to laboratory tasks.  

PubMed

To examine whether transfer of heart rate (HR) feedback training to tasks not used during training could be improved by using multiple tasks during training, a modified multiple baseline across tasks, single subject design study was conducted using six high HR-reactive young adults. Participants received HR feedback training during the presentation of a videogame, and transfer of training was assessed to a mental arithmetic challenge and handgrip task. Transfer of training was next assessed following training with the mental arithmetic challenge and handgrip task. HR responses to each training task with no HR feedback were assessed during a pre-treatment session, an immediate post-training period following training on each task, a short delay (1-2 days) post-training session, and a long delay (1-2 weeks) post-training session. HR response to a novel speech task was assessed at pre-treatment and during short delay and long delay post-training sessions. Results revealed that participants reduced HR during training and generally maintained this reduction in HR during the immediate post-training assessment when HR feedback was not present. Participants were not able to reduce HR responses to tasks during short delay and long delay post-training sessions, and they were unable to transfer HR reduction skills to the speech task. Transfer of HR feedback training to new tasks was limited in nature and efforts to train across multiple stressors did not appear to improve transfer of training. PMID:16906468

Goodie, Jeffrey L; Larkin, Kevin T

2006-09-01

194

Effect of pacemaker rate-adaptation on 24h beat-to-beat heart rate and blood pressure profiles  

Microsoft Academic Search

Abstract,Aims,The aims,of the study,were,to evaluate,the 24-h beat-to-beat heart rate (RR) and,blood,pressure,changes,during closed,loop stimulation,(DDD- CLS) pacing,and,conventional,fixed rate DDD pacing,with respect,to spontaneous activity. Methods,We simultaneously,and,continuously,measured,beat-to-beat heart rate and blood pressure for 24 h in patients implanted with Inos,C (Biotronik GmbH, Berlin, Germany). A randomised cross-over comparison of DDD-CLS and DDD pacing was,performed,by short- and long-term analyses. Results Seventeen patients (10 males, aged

Raffaele Quaglione; Giovanni Calcagnini; Federica Censi; Mario Malavasi; Marco Raveggi; Gianluca Biancalana; Pietro Bartolini; Giuseppe Critelli

2005-01-01

195

Fetal Heart Rate Monitoring during Labor  

MedlinePLUS

... method of periodically listening to the fetal heartbeat. Electronic fetal monitoring is a procedure in which instruments ... be checked and recorded more frequently. How is electronic fetal monitoring performed? Electronic fetal monitoring uses special ...

196

Thermal Acclimation of Heart Rates in Reptilian Embryos  

Microsoft Academic Search

In many reptiles, the thermal regimes experienced by eggs in natural nests vary as a function of ambient weather and location, and this variation has important impacts on patterns of embryonic development. Recent advances in non-invasive measurement of embryonic heart rates allow us to answer a long-standing puzzle in reptilian developmental biology: Do the metabolic and developmental rates of embryos

Wei-Guo Du; Hua Ye; Bo Zhao; Daniel A. Warner; Richard Shine; Yan Ropert-Coudert

2010-01-01

197

The Use of Heart Rate Monitors in Physical Education  

ERIC Educational Resources Information Center

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

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

2009-01-01

198

The effect of uterine rupture on fetal heart rate patterns  

Microsoft Academic Search

The high success rate of vaginal birth after cesarean section (VBAC) and its low association with complications has led to VBACs being attempted at all types of facilities, including birth centers. It must be kept in mind that unpredictable uterine rupture can occur and that uterine rupture necessitates emergency intervention. The only reported predictable feature of fetal heart rate patterns

Cydney Afriat Menihan

1999-01-01

199

Heart rate variability and autonomic nerve activities in ambulatory dogs.  

PubMed

Analysis of heart rate variability is a valuable method to investigate the sympathetic and parasympathetic function of the autonomic nervous system. Although such analyses can provide quantitative estimates of autonomic neural activity, simultaneous recording of neural activities and ECG will allow more direct investigation of neural modulation of heart rate. We developed a method that allows direct and long-term recording of neural activities and ECG using wireless device implanted in ambulatory dogs. The aim of this study was to investigate the relationship between autonomic neural firing and heart rate variability. In this study, HRV and neural activities were assessed for 5 continuous days. HRV was evaluated by calculating the mean and the standard deviation of inter-beat intervals in 24 hours. Neural activities were obtained by the sum of the filtered rectified neural signals after 200 Hz high-pass filtering to remove ECG interference. The plots showing HRV as a function of both the sympathetic and vagal activities will offer significant insights into neural modulation of heart rate in normal and diseased hearts. PMID:17946069

Song, Juan; Ogawa, Masahiro; Tan, Alex Y; Chen, Peng-Sheng; Lin, Shien-Fong

2006-01-01

200

Exaggerated heart rate oscillations during two meditation techniques.  

PubMed

We report extremely prominent heart rate oscillations associated with slow breathing during specific traditional forms of Chinese Chi and Kundalini Yoga meditation techniques in healthy young adults. We applied both spectral analysis and a novel analytic technique based on the Hilbert transform to quantify these heart rate dynamics. The amplitude of these oscillations during meditation was significantly greater than in the pre-meditation control state and also in three non-meditation control groups: i) elite athletes during sleep, ii) healthy young adults during metronomic breathing, and iii) healthy young adults during spontaneous nocturnal breathing. This finding, along with the marked variability of the beat-to-beat heart rate dynamics during such profound meditative states, challenges the notion of meditation as only an autonomically quiescent state. PMID:10454297

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

1999-07-31

201

Impaired heart rate recovery in patients with endemic fluorosis.  

PubMed

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

2013-02-16

202

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

Microsoft Academic Search

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

Tushar P Thakre; Michael L Smith

2006-01-01

203

Pathophysiology of exercise heart rate recovery: a comprehensive analysis.  

PubMed

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. PMID:23530480

Pierpont, Gordon L; Adabag, Selcuk; Yannopoulos, Demetri

2013-03-01

204

Heart rate variability and cognitive function: effects of physical effort.  

PubMed

This study investigated alterations in heart rate variability (HRV) and cognitive performance before and after physical effort, for 30 high-level track and field athletes (23 males and 7 females). Interbeat intervals were assessed at the baseline and during each task of a CogState cognitive battery (simple reaction time, choice reaction time, working memory, short-term memory and sustained attention). Time and frequency domain measures of HRV were compared between conditions and between tasks. The results indicated differences in HRV between executive and non-executive tasks. There was a significant increase in sympathetic-modulation-related indices after physical effort. The differences between executive and non-executive tasks were the same in post-test. Correlations were found between HRV and cognitive performance, which differed by speed and accuracy. We conclude that HRV is related to cognitive demand and that the correlation between HRV and cognitive performance seems to be stronger after physical exercise. The results raise questions about the psychophysiological meaning of different HRV signals and this has implications for future research about the relationship between HRV and cognition. PMID:19632295

Luft, Caroline Di Bernardi; Takase, Emílio; Darby, David

2009-07-24

205

Double blind crossover comparison of the effects of dual chamber pacing (DDD) and ventricular rate adaptive (VVIR) pacing on neuroendocrine variables, exercise performance, and symptoms in complete heart block  

Microsoft Academic Search

OBJECTIVE--To compare the effects of dual chamber pacing (DDD) and ventricular rate adaptive pacing (activity sensing) (VVIR) in patients with complete heart block. DESIGN--Double blind crossover comparison with one month in each pacing mode. PATIENTS--10 consecutive patients aged 23-74 presenting with complete anterograde atrioventricular block at rest and on exercise and with an intact atrial rate response received Synergyst I

K G Oldroyd; A P Rae; R Carter; C Wingate; S M Cobbe

1991-01-01

206

Analysis of the work rates and heart rates of association football referees  

Microsoft Academic Search

This study aimed to describe the work-rate profiles of referees during soccer matches and record heart-rate responses during these games. Using video-recordings 14 referees were observed and their heart rates during the games were monitored by short-range radio telemetry. These included 11 football league matches. The exercise intensity was largely submaximal with a change in activity every 6 s. The

C Catterall; T Reilly; G Atkinson; A Coldwells

1993-01-01

207

Delayed heart rate recovery after adenosine stress testing with supplemental arm exercise predicts mortality  

Microsoft Academic Search

Background  Delayed heart rate (HR) recovery after treadmill exercise testing predicts mortality. Patients with suspected ischemic heart\\u000a disease who cannot perform adequate treadmill exercise are typically evaluated with pharmacological stress myocardial perfusion\\u000a imaging (MPI) studies, but little prognostic significance has been attributed to the hemodynamic response to vasodilator stress\\u000a testing with low-level exercise. We hypothesized that a delay in HR recovery

Yasushi Akutsu; Shawn A. Gregory; Arash Kardan; Gerasimos D. Zervos; Gregory S. Thomas; Henry Gewirtz; Tsunehiro Yasuda

2009-01-01

208

Low-dose coronary-CT angiography using step and shoot at any heart rate: comparison of image quality at systole for high heart rate and diastole for low heart rate with a 128-slice dual-source machine.  

PubMed

To compare image quality of coronary CT angiography in step-and-shoot mode at the diastolic phase at low heart rates (<70 bpm) and systolic phase at high heart rates (?70 bpm). We prospectively included 96 consecutive patients then excluded 5 patients with arrhythmia. Coronary CT-angiography was performed using a dual-source 128-slice CT machine, at the diastolic phase in the 55 patients with heart rates <70 bpm (group D) and at the systolic phase in the 36 patients with heart rates ?70 (group S). Image quality was scored on a 5 point-scale (1, not interpretable; 2, insufficient for diagnosis; 3, fair, sufficient for diagnosis; 4, good; 5, excellent). In addition, we compared the number of stair-step artifacts in the two groups. Mean image quality score was 4 (0.78) in group D and 4.1 (0.34) in group S (NS), with an unequal distribution (p = 0.01). Step artifacts were seen in 44 % of group D and 18 % of group S patients (p = 0.02). In 3 group D patients and no group S patients, the image score was <3 due to artifacts, requiring repeat CT-angiography. When performing dual-source 128-slice CT-angiography, step-and-shoot acquisition provides comparable mean image quality in systole, with less variability and fewer stair-step artifacts, compared to diastole. This method may be feasible at any heart rate in most patients in sinus rhythm, allowing low-dose prospective acquisition without beta-blocker premedication. PMID:22918571

Paul, Jean-François; Amato, Aude; Rohnean, Adela

2012-08-24

209

Electrocardiographic Measures and Heart Rate Variability in Patients with Familial Dysautonomia  

Microsoft Academic Search

Cardiovascular abnormalities are prominent in the genetic disorder, familial dysautonomia (FD). To determine if autonomic dysfunction involves cardiac, as well as peripheral vascular integrity, noninvasive tests were performed in 10 FD patients and 8 healthy control subjects while supine and at 90° tilt. Simultaneous blood pressure (BP) and heart rate (HR) and QTc were obtained, while performing signal-averaged electrocardiography (SAECG)

Felicia B. Axelrod; Donald Putman; Dena Berlin; Monika Rutkowski

1997-01-01

210

Human circadian rhythms in heart rate response to a maximal exercise stress  

Microsoft Academic Search

Circadian rhythmicity of maximum heart rate response to an exercise task was studied using ten male subjects. Resting heart rate data were collected at seven separate times during a 24 hour period. Exercise heart rate data werecollected at the exact same times, as follows: 0400,0800, 1200, 1500, 1800,2100 and 2400 h. Lowest resting heart rate for all subjects occurred at

C. J. COHEN

1980-01-01

211

Remote Measurements of Heart and Respiration Rates for Telemedicine  

PubMed Central

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

212

Remote measurements of heart and respiration rates for telemedicine.  

PubMed

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

213

Depressed heart rate variability is associated with events in patients with stable coronary artery disease and preserved left ventricular function  

Microsoft Academic Search

Background: Little is known about the value of heart rate variability in patients with symptomatic coronary artery disease with a preserved left ventricular function. We hypothesized that in these patients heart rate variability might be a helpful adjunct to conventional parameters to predict clinical events. Methods: In a prospective 2-year follow-up study ambulatory electrocardiographic recordings were performed in 263 consecutive

Ad J. van Boven; J. Wouter Jukema; Jaap Haaksma; Aeilko H. Zwinderman; Harry J. G. M. Crijns; Kong I. Lie

1998-01-01

214

Changes in Heart Rate Variability in Patients under Local Anesthesia  

Microsoft Academic Search

Spectral analysis of Heart Rate Variability (HRV) is widely used for the assessment of cardiovascular autonomic control. Several studies have shown the effect of anesthetic agents on HRV parameters. In this study a systematic approach of HRV analysis has been employed. The effect caused by the ectopic beats on the spectral measurements has been investigated and results are presented. A

K. Shafqat; S. K. Pal; S. Kumari; P. A. Kyriacou

2007-01-01

215

Relationship between Exercise Heart Rate and Music Tempo Preference  

ERIC Educational Resources Information Center

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

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

2006-01-01

216

Heart Rate Variability: Effect of Exercise Intensity on Postexercise Response  

ERIC Educational Resources Information Center

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

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

2012-01-01

217

Depression, heart rate variability, and exercise training in dialysis patients  

Microsoft Academic Search

Background Functional limitations, altered cardiac autonomic activity, and psychological distress are known disorders in chronic hemodialysis (HD) patients, relating to increased morbidity and mortality. The aim of this study was to examine the influence of an exercise training program on emotional parameters and heart rate variability (HRV) indices, as well as to determine whether emotional stress contributes to autonomic dysfunction

Evangelia Kouidi; Vassilis Karagiannis; Dimitrios Grekas; Apostolos Iakovides; George Kaprinis; Achilleas Tourkantonis; Asterios Deligiannis

2010-01-01

218

Relationship between major depression and heart rate variability  

Microsoft Academic Search

A high sympathetic and\\/or a low cardiovagal activity in patients with major depression (MD) may contribute to the higher cardiac morbidity and mortality of MD patients. Standardized tests of heart rate variability (HRV) allow a quantitative estimation of autonomic nervous system function. However, previous studies on the relationship between HRV and MD have revealed conflicting results. Our study compared time

Marcus W Agelink; Cavit Boz; Heiko Ullrich; Jürgen Andrich

2002-01-01

219

Power Spectral Analysis of Heart Rate Variability in Psychiatry  

Microsoft Academic Search

Power spectrum analysis of heart rate variability (PSA of HRV) is a promising method, which can be used as an index of cardiac autonomic balance. PSA of HRV is a noninvasive technique, based on ECG sampling of RR interval variation, thus providing a dynamic assessment of sympathetic and parasympathetic tone, reflecting the interactions between the two. It has been shown

Hagit Cohen; Michael A. Matar; Zeev Kaplan; Moshe Kotler

1999-01-01

220

Depression, Heart Rate Variability, and Acute Myocardial Infarction  

Microsoft Academic Search

Background—Clinical depression is associated with an increased risk for mortality in patients with a recent myocardial infarction (MI). Reduced heart rate variability (HRV) has been suggested as a possible explanation for this association. The purpose of this study was to determine if depression is associated with reduced HRV in patients with a recent MI. Methods and Results—Three hundred eighty acute

Robert M. Carney; James A. Blumenthal; Phyllis K. Stein; Lana Watkins; Diane Catellier; Lisa F. Berkman; Susan M. Czajkowski; Christopher O'Connor; Peter H. Stone; Kenneth E. Freedland

221

Influence of Vertical Vibration on Heart Rate of Pigs1  

Microsoft Academic Search

Pigs with a body weight between 15 and 20 kg were vibrated in the vertical direction for 1 h at 2, 8, and 18 Hz, in combination with root mean square (RMS) acceleration magnitudes of 1 or 3 m\\/s2. Welfare and stress were quantified by comparing heart rate characteristics during a control period (2200 to 0600) before vibration exposure and

S. Perremans; J. M. Randall; L. Allegaert; M. A. Stiles; G. Rombouts; R. Geers

2010-01-01

222

Identifying chaos from heart rate: The right task?  

NASA Astrophysics Data System (ADS)

Providing a conclusive answer to the question ``is this dynamics chaotic?'' remains very challenging when experimental data are investigated. We showed that such a task is actually a difficult problem in the case of heart rates. Nevertheless, an appropriate dynamical analysis can discriminate healthy subjects from patients.

Freitas, Ubiratan; Roulin, Elise; Muir, Jean-François; Letellier, Christophe

2009-06-01

223

Heart rate variability is altered following spinal cord injury  

Microsoft Academic Search

Spinal cord injury (SCI) patients are know to suffer from autonomic failure as a result of their injury. The magnitude of the dysautonomia resulting from such an injury is difficult to predict or characterize and, in varying degree, it impedes the recovery of physiological homeostasis. This study is intended to investigate the effectiveness of heart rate variability (HRV) analysis as

David C. Bunten; Alberta L. Warner; Sherry R. Brunnemann; Jack L. Segal

1998-01-01

224

Heart Rate Monitors Promote Physical Education for Children  

ERIC Educational Resources Information Center

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

Tipton, Jan; Sander, Allan N.

2004-01-01

225

Formulas for Dynamic Exercise Heart Rate and Blood Pressure  

Microsoft Academic Search

Formulas are proposed for the ranges of normal heart rate and blood pressure during dynamic exercise. They apply to normotensive men and women approximately 20–50 years old. The numerical values of the parameters may have to be modified for other populations, partial populations or other age groups.

Ernst H. Jager

2000-01-01

226

Heart Rate Variability and Drawing Impairment in Hypoxemic COPD  

ERIC Educational Resources Information Center

|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

227

Heart Rate Variability on Exposure to Severe Gold at Antarctica  

Microsoft Academic Search

An attempt has been made to evaluate Heart Rate Variability (HRV) as a reliable index for sympathetic and parasympathetic components of the autonomic nervous system response during the course of acclimatization to severe cold at Antarctica. Two groups (10 each) of healthy men in the age group of 2344 years participated in the study. Group A consisted of fresh inductees

K. Harinath; A. S. Malhotra; Karan Pal; R. Prasad; R. C. Sawhney

228

How to interpret psychology from heart rate variability?  

Microsoft Academic Search

In this paper, we have used the color stimuli to define the arousal level of subjects by analyzing their heart rate variability (HRV). For this analysis, we have used the novel Triangular Phase Space Mapping (TPSM) and try to distinguish two groups of emotions, calm and energetic. The results show that cold colors are associated with low arousal level and

Sadaf Moharreri; Nader Jafarnia Dabanloo; Saman Parvaneh; Ali M Nasrabadi

2011-01-01

229

Long-term measurement of heart rate in chicken eggs  

Microsoft Academic Search

Taking advantage of acoustocardiogram (ACG), we measured the heart rate (HR) of chick embryos continuously from day 12 until hatching and then investigated the development of HR irregularities (HRI), HR variability (HRV), and the existence of a circadian rhythm in mean HR (MHR). HRI comprised transient bradycardia and tachycardia, which first developed on day 14 and 16 in most embryos,

Ryuichi Akiyama; Akira Matsuhisa; James T Pearson; Hiroshi Tazawa

1999-01-01

230

Alteration of Heart Rate Variability Parameters in Nondiabetic Hemodialysis Patients  

Microsoft Academic Search

Objective: We attempt to identify heart rate variability (HRV) components and decide whether or not such components are more sensitive to the hemodialysis (HD) process by excluding the presence of comorbid conditions known to affect HRV. Methods: It was a prospective cohort study of factors associated with HRV. Thirty-five HD patients were admitted to the study. The research was divided

Yan-Qing Tong; Huo-Ming Hou

2007-01-01

231

Exploring the Relationship between Fetal Heart Rate and Cognition  

ERIC Educational Resources Information Center

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

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

2010-01-01

232

Acupuncture and heart rate variability: A systematic review  

Microsoft Academic Search

Acupuncture has been reported to affect the autonomic system. Currently, there are no systematic reviews examining the effect of acupuncture on HRV available in the literature. Therefore, the aim of this systematic review was to summarize and critically assess the effects of acupuncture on heart rate variability. We searched the literature using 14 databases for articles published from the earliest

Sanghoon Lee; Myeong Soo Lee; Jun-Yong Choi; Seung-Won Lee; Sang-Yong Jeong; Edzard Ernst

2010-01-01

233

Sleep-Wakefulness Determinations from Heart Rate Data.  

National Technical Information Service (NTIS)

During the second year of this research the REM-NREM algorithm developed during the first year of work to separate the sleep cycles on the basis of minute-by-minute heart rate was re-evaluated on new data as was the algorithm for separation and classifica...

P. C. Richardson A. J. Welch M. J. Lisenby T. P. Daubek

1976-01-01

234

Acute Effect of Cigarette Smoking on Heart Rate Variability  

Microsoft Academic Search

Acute cigarette smoking enhances adrenergic activity and thus may be associated with hemodynamic changes in the cardiovascular system. In this study, the acute effect of cigarette smoking on heart rate variability (HRV) was studied. Fifteen subjects were included in the study. Time domain (the mean R-R interval, the standard deviation of R-R interval, and the root mean square of successive

Osman Karakaya; Irfan Barutcu; Dayimi Kaya; Ali Metin Esen; Mustafa Saglam; Mehmet Melek; Ersel Onrat; Muhsin Turkmen; Ozlem Batukan Esen; Cihangir Kaymaz

2007-01-01

235

Transient suppression of heart rate complexity in concussed athletes  

Microsoft Academic Search

Heart rate variability (HRV) and complexity (HRC) were calculated at rest and during an isometric hand grip test (IHGT) within 48-hours (48 h) and two weeks (Week Two) of a concussion in athletes (CG) and control subjects. No differences were present at rest or in HRV during IGHT. HRC was significantly lower in the CG compared to controls at 48 h during

Michael F. La Fountaine; Kevin S. Heffernan; James D. Gossett; William A. Bauman; Ronald E. De Meersman

2009-01-01

236

The Effect of Colored Illumination on Heart Rate Variability  

Microsoft Academic Search

We investigated the effects of illumination with colored fluorescent light on heart rate variability (HRV) and autonomic regulation. Previous examinations have only focused on full-spectrum fluorescent bright light as it is used for the therapy of seasonal affective disorder and disturbances of circadian rhythms. Materials and Methods: In 3 experiments, 12 healthy volunteers were exposed for 10 min to red,

Axel Schäfer; Karl W. Kratky

2006-01-01

237

Discriminative heart rate conditioning with sustained inspiration as respiratory control  

Microsoft Academic Search

In a classical discrimination paradigm with instructions to expect shock at certain temporal loci used to obtain anticipatory heart rate CRs, Ss expected shock on a specific flash in 5 red sequences (CS+ trials), but not in 5 white sequences (CS-). 2 groups were compared with their preconditioning controls with the same respiration. The Normal Respiration group showed acceleration-deceleration on

Robert W. Smith

1966-01-01

238

Heart rate variability analysis during central hypovolemia using wavelet transformation.  

PubMed

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. PMID:23371800

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

2013-02-01

239

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

PubMed Central

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

240

Longitudinal analysis of heart rate variability in chronic hypertensive pregnancy.  

PubMed

In the US, it is currently estimated that 3% of pregnant women have chronic hypertension, or more than 100,000 pregnant women each year. The aim of our study was to investigate the adaptation of autonomic control during pregnancy based on heart rate variability analysis and to determine whether chronic hypertension during pregnancy has an impact on this adaptation. Sixteen pregnant women with chronic hypertension (CH group; mean age, 30 years; range, 25-33 years) and 35 healthy pregnant women serving as controls (CON group; mean age, 28 years; range, 24-30 years) were recruited for this longitudinal study. Beginning at the 20th week of pregnancy, the women were monitored every 4th week until delivery. For the analysis of heart rate variability, Portapres signals (200 Hz) were recorded for 30 min under resting conditions. Women in the CH group had significantly elevated blood pressure compared to controls (CON, 111 mmHg [105-132]; CH, 140 mmHg [132-148]; p<0.001). An increased heart rate was found in both groups during the second half of pregnancy. Consequently, decreased heart rate variability was observed, but was more pronounced in the CON group. There was a shift in the frequency bands indicated by an elevation of the low-to-high frequency ratio (LF/HF) in both groups due to a decrease in HF, and thus a significant increase in LFn (LF power in normalized units). However, VLF (power of very low frequency range) increased exclusively in the CON pregnancies. Our data showed no significant difference in heart rate variability between the subjects of the CH and CON groups. Longitudinal variations were detectable in normal pregnancies and also, albeit to a lesser degree, in chronic hypertensive pregnant women. Thus, our data indicate that patients with long-term hypertension are still able to respond to the physiological changes occurring during pregnancy. PMID:16025737

Walther, Thomas; Wessel, Niels; Baumert, Mathias; Stepan, Holger; Voss, Andreas; Faber, Renaldo

2005-02-01

241

Severe depression is associated with markedly reduced heart rate variability in patients with stable coronary heart disease  

Microsoft Academic Search

Objective: The purpose of this study was to investigate the relationship between depression and heart rate variability in cardiac patients. Methods: Heart rate variability was measured during 24-hour ambulatory electrocardiographic (ECG) monitoring in 40 medically stable out-patients with documented coronary heart disease meeting current diagnostic criteria for major depression, and 32 nondepressed, but otherwise comparable, patients. Patients discontinued ?-blockers and

Phyllis K Stein; Robert M Carney; Kenneth E Freedland; Judith A Skala; Allan S Jaffe; Robert E Kleiger; Jeffrey N Rottman

2000-01-01

242

The relationship between heart rate and oxygen consumption in heart transplant recipients during a cardiopulmonary exercise test  

Microsoft Academic Search

BackgroundIn healthy subjects, the percentage of heart rate reserve (%HRR) versus the percentage of oxygen consumption reserve (%VO2R) is the closest relationship between heart rate and VO2 and it seems also to be true to heart failure patients only if they are under optimized beta-blocker therapy.

Vitor Oliveira Carvalho; Edimar Alcides Bocchi; Lucas Nóbilo Pascoalino; Guilherme Veiga Guimarães

2010-01-01

243

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

PubMed

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. PMID:20403733

Al Haddad, Hani; Laursen, Paul B; Chollet, Didier; Lemaitre, Frédéric; Ahmaidi, Saïd; Buchheit, Martin

2010-04-18

244

A heart rate sensor based on seismocardiography for vital sign monitoring systems  

Microsoft Academic Search

Heart rate is essential in monitoring the health of an individual. Traditional use of ECG to measure the heart beat poses complication in many applications. There is need for a less intrusive, simple, easy to use, and versatile heart rate sensor. This paper describes the design and testing of a heart rate sensor using a low cost accelerometer. The design

Anh Dinh; Younhee Choi; Seok-Bum Ko

2011-01-01

245

Assessment of mental stress in warmblood horses: heart rate variability in comparison to heart rate and selected behavioural parameters  

Microsoft Academic Search

The aim of the study was to investigate whether heart rate variability (HRV) could assess alterations of the autonomic nervous system (ANS) at different levels of excitement. The behavioural and physiological responses of 20 warmblood horses to a challenging ground exercise task were studied. Prior to the experiment, the horses were evaluated at rest and during forward walking (FW). The

T. R. Rietmann; A. E. A. Stuart; P. Bernasconi; M. Stauffacher; J. A. Auer; M. A. Weishaupt

2004-01-01

246

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

National Technical Information Service (NTIS)

In this work we have analyzed changes in the heart rate variability (HRV) during exercise test comparing them with the ST deviation criteria to improve the diagnostic value of the exercise test. Coronary angiography was considered as gold standard to esta...

J. Mateo P. Serrano R. Bailon J. Garcia A. Ferreira

2001-01-01

247

Running demands and heart rate response in rugby union referees.  

PubMed

Suarez-Arrones, L, Portillo, LJ, García, JM, Calvo-Lluch, A, Roberts, SP, and Mendez-Villanueva, A. Running demands and heart rate response in rugby union referees. J Strength Cond Res 27(11): 2946-2951, 2013-The aim of this study was to examine the match physical demands and exercise intensity associated with men rugby union refereeing using global positioning system technology. Ten male rugby union referees (age, 37.1 ± 5.9 years; body mass, 83.7 ± 4.8 kg; height, 175.5 ± 6.2 cm) were analyzed 2-4 times during a total of 30 national level matches. The average total distance covered by the referees throughout the game was 6,322.2 ± 564.9 m. As a percentage of total distance, 37.3% (2,356.9 ± 291.3 m) was spent walking, 24.1% (1,524.4 ± 229.4 m) jogging, 10.4% (656.2 ± 130.7 m) running at low intensity, 17.6% (1,110.3 ± 212.2 m) at medium intensity, 5.5% (347.1 ± 27.1 m) at high intensity, and 5.2% (328.1 ± 230.3 m) at sprint. A significant decrease (p < 0.05) in running performance was observed between the first and the second halves in the last 3 speed zones. When the total distance traveled during consecutive 10-minute periods was compared, there was a significantly greater distance covered in the first 10 minutes of the game (876.3 ± 163 m) compared with 50-60 minutes (679.8 ± 117.6 m), 60-70 minutes (713.03 ± 122.3 m), and 70-80 minutes (694.2 ± 125.7 m; all p < 0.05). The average heart rate responses were similar (p > 0.05) in the first (157 ± 7 b·min; 85% HRmax) and second half (155 ± 7 b·min; 84% HRmax). This study provides evidence of reduced high-intensity running toward the end of the game. These findings offer important information to design better training strategies adapted to the requirements and demands of rugby union refereeing. PMID:23439341

Suarez-Arrones, Luis; Portillo, Luis J; García, Jose M; Calvo-Lluch, Africa; Roberts, Simon P; Mendez-Villanueva, Alberto

2013-11-01

248

Gender differences in personality and heart-rate variability.  

PubMed

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. PMID:23499230

Huang, Wei-Lieh; Chang, Li-Ren; Kuo, Terry B J; Lin, Yu-Hsuan; Chen, Ying-Zai; Yang, Cheryl C H

2013-03-15

249

Genome-wide association analysis identifies multiple loci related to resting heart rate  

PubMed Central

Higher resting heart rate is associated with increased cardiovascular disease and mortality risk. Though heritable factors play a substantial role in population variation, little is known about specific genetic determinants. This knowledge can impact clinical care by identifying novel factors that influence pathologic heart rate states, modulate heart rate through cardiac structure and function or by improving our understanding of the physiology of heart rate regulation. To identify common genetic variants associated with heart rate, we performed a meta-analysis of 15 genome-wide association studies (GWAS), including 38 991 subjects of European ancestry, estimating the association between age-, sex- and body mass-adjusted RR interval (inverse heart rate) and ?2.5 million markers. Results with P < 5 × 10?8 were considered genome-wide significant. We constructed regression models with multiple markers to assess whether results at less stringent thresholds were likely to be truly associated with RR interval. We identified six novel associations with resting heart rate at six loci: 6q22 near GJA1; 14q12 near MYH7; 12p12 near SOX5, c12orf67, BCAT1, LRMP and CASC1; 6q22 near SLC35F1, PLN and c6orf204; 7q22 near SLC12A9 and UfSp1; and 11q12 near FADS1. Associations at 6q22 400 kb away from GJA1, at 14q12 MYH6 and at 1q32 near CD34 identified in previously published GWAS were confirmed. In aggregate, these variants explain ?0.7% of RR interval variance. A multivariant regression model including 20 variants with P < 10?5 increased the explained variance to 1.6%, suggesting that some loci falling short of genome-wide significance are likely truly associated. Future research is warranted to elucidate underlying mechanisms that may impact clinical care.

Eijgelsheim, Mark; Newton-Cheh, Christopher; Sotoodehnia, Nona; de Bakker, Paul I.W.; Muller, Martina; Morrison, Alanna C.; Smith, Albert V.; Isaacs, Aaron; Sanna, Serena; Dorr, Marcus; Navarro, Pau; Fuchsberger, Christian; Nolte, Ilja M.; de Geus, Eco J.C.; Estrada, Karol; Hwang, Shih-Jen; Bis, Joshua C.; Ruckert, Ina-Maria; Alonso, Alvaro; Launer, Lenore J.; Hottenga, Jouke Jan; Rivadeneira, Fernando; Noseworthy, Peter A.; Rice, Kenneth M.; Perz, Siegfried; Arking, Dan E.; Spector, Tim D.; Kors, Jan A.; Aulchenko, Yurii S.; Tarasov, Kirill V.; Homuth, Georg; Wild, Sarah H.; Marroni, Fabio; Gieger, Christian; Licht, Carmilla M.; Prineas, Ronald J.; Hofman, Albert; Rotter, Jerome I.; Hicks, Andrew A.; Ernst, Florian; Najjar, Samer S.; Wright, Alan F.; Peters, Annette; Fox, Ervin R.; Oostra, Ben A.; Kroemer, Heyo K.; Couper, David; Volzke, Henry; Campbell, Harry; Meitinger, Thomas; Uda, Manuela; Witteman, Jacqueline C.M.; Psaty, Bruce M.; Wichmann, H-Erich; Harris, Tamara B.; Kaab, Stefan; Siscovick, David S.; Jamshidi, Yalda; Uitterlinden, Andre G.; Folsom, Aaron R.; Larson, Martin G.; Wilson, James F.; Penninx, Brenda W.; Snieder, Harold; Pramstaller, Peter P.; van Duijn, Cornelia M.; Lakatta, Edward G.; Felix, Stephan B.; Gudnason, Vilmundur; Pfeufer, Arne; Heckbert, Susan R.; Stricker, Bruno H.Ch.; Boerwinkle, Eric; O'Donnell, Christopher J.

2010-01-01

250

Voluntary Control of Human Heart Rate. Effect on Reaction to Aversive Stimulation.  

National Technical Information Service (NTIS)

In anticipation of receiving painful stimuli, 20 female subjects learned to control their heart rate when provided with external feedback and reward for criterion heart rate changes and were instructed to increase or decrease their rate. Voluntary slowing...

A. D. Sirota G. E. Schwartz D. Shapiro

1973-01-01

251

Heart Rate Variability Analysis of Ischemic and Heart Rate Related ST-segment Deviation Episodes Based on Time-frequency Method  

Microsoft Academic Search

ST-segment deviation is the routine method for the diagnosis of coronary heart diseases. However, other phenomena, such as heart rate changes and a posture change can cause similar manifestations in the ST segment, lowing the sensitivity and specificity of the detection. In this study, a different method, based on time-frequency analysis of heart rate variability, was proposed to evaluate the

Wang Xing; Xu Liang; Sun Zhongwei; Yang Zibin; Peng Yi

2007-01-01

252

Heart rate changes in cardiac transplant patients and in the denervated cat heart after edrophonium  

Microsoft Academic Search

Purpose  The effect of edrophonium on heart rate in cardiac transplant patients and in an animal model of acute cardiac denervation\\u000a were studied, to evaluate the functional state of the peripheral parasympathetic pathway fol lowing cardiac denervation.\\u000a \\u000a \\u000a \\u000a Methods  Edrophonium was studied in patients with normally innervated hearts (controls) and m cardiac trans plants. Edrophonium was\\u000a also studied in vagotomized. beta-blocked cats. In

Steven B. Backman; Reuben D. Stein; Gordon S. Fox; Canio Polosa

1997-01-01

253

Sampling period determination for heart rate logging under an exercise regimen  

Microsoft Academic Search

Using a mathematical procedure, we determine appropriate sampling rates for logging heart rate, at a variety of exercise intensities. The mathematical procedure involves correlating exercise and heart rate data to determine a dynamical mathematical model, from which the frequency response of the relationship between exercise intensity and heart rate can be determined. The sampling rate is then straightforwardly deduced by

M. McCarthy; J. V. Ringwood

2006-01-01

254

Use of reversed regulation of work rate intensity by heart rate in testing physical fitness (CHR test)  

Microsoft Academic Search

A method of testing endurance capacity and physical fitness (40?minute test) based on control of the test work rate by a defined heart rate (clamped heart rate [CHR] test) is proposed. This test was used on 26 men and 19 women with sedentary occupations, about half of whom had regular unorganized sporting activity. A subject's physiologic reaction to a heart

Pavel Stejskal; Richard Sup; Ivo Doležal; Jindriška Hejnová

1993-01-01

255

The predictive value of low heart rate and heart rate variability during stress for reoffending in delinquent male adolescents.  

PubMed

Low autonomic (re)activity is a consistent correlate of antisocial behavior in juveniles. However, longitudinal research relating autonomic measures to persistent antisocial behavior has remained scarce. Therefore, in the present study we examined the predictive value of heart rate (HR) and heart rate variability (HRV, often studied as respiratory sinus arrhythmia) for reoffending in delinquent male adolescents. At initial assessment, HR and HRV were measured at rest and in response to a public speaking task. Registered reoffending was assessed after 5-year follow-up. Attenuated HR response and stronger HRV response to stress predicted higher reoffending rates. Results provide evidence that HR/HRV reactivity are neurobiological markers for persistent juvenile antisocial behavior. Although effect sizes were small to moderate, our findings underscore the consistency of the relationship between autonomic markers and antisocial behavior. PMID:21824152

De Vries-Bouw, Marjan; Popma, Arne; Vermeiren, Robert; Doreleijers, Theo A H; Van De Ven, Peter M; Jansen, Lucres M C

2011-08-08

256

An arrhythmia detector and heart rate estimator for overnight polysomnography studies  

Microsoft Academic Search

We present an algorithm for automatic on-line analysis of the ECG channel acquired during overnight polysomnography (PSG) studies. The system is independent of ECG morphology, requires no manual initialization, and operates automatically throughout the night. It highlights likely occurrences of arrhythmias and intervals of bad signal quality while outputting a continual estimate of heart rate. Algorithm performance is validated against

Anton Bartolo; Bradley D. Clymer; Richard C. Burgess; John P. Turnbull; Joseph A. Golish; Michael C. Perry

2001-01-01

257

Evaluation of two detrending techniques for application in Heart Rate Variability  

Microsoft Academic Search

The performance of two different algorithms of detrending the RR-interval before Heart Rate Variability (HRV) analysis has been evaluated using both, simulated signals and real RR-interval time series. The first algorithm is based on the smoothness prior approach (SPA) and the second algorithm is implemented using wavelet packet (WP) analysis. The calculated time and frequency domain parameters obtained from real

K. Shafqat; S. K. Pal; P. A. Kyriacou

2007-01-01

258

Electroencephalogram and Heart Rate Measures of Working Memory at 5 and 10 Months of Age  

ERIC Educational Resources Information Center

|We recorded electroencephalogram (EEG; 6-9 Hz) and heart rate (HR) from infants at 5 and 10 months of age during baseline and performance on the looking A-not-B task of infant working memory (WM). Longitudinal baseline-to-task comparisons revealed WM-related increases in EEG power (all electrodes) and EEG coherence (medial frontal-occipital…

Cuevas, Kimberly; Bell, Martha Ann; Marcovitch, Stuart; Calkins, Susan D.

2012-01-01

259

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

Microsoft Academic Search

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.

Giuseppe Verlato; Enrico Polati; Giorgio Speranza; Gabriele Finco; Leonardo Gottin; Stefano Ischia

2001-01-01

260

Heart rate, blood lactate concentration, and time–motion analysis of female basketball players during competition  

Microsoft Academic Search

The aim of this study was to examine the physiological demands and movement patterns of female basketball players after changes in the rules of the game. Nine varsity players were studied during nine official games. Each game was videotaped to identify the frequencies of the main movements performed, heart rate was recorded continuously, and blood samples were collected to determine

Dionne Matthew; Anne Delextrat

2009-01-01

261

Surgical left cardiac sympathetic denervation for long QT syndrome: effects on QT interval and heart rate  

Microsoft Academic Search

The primary aim of the present study was to investigate the short-term effects of surgical left cardiac sympathetic denervation (LCSD) on the QT interval and heart rate in patients with congenital long QT syndrome (LQTS). Left cardiac sympathetic denervation was performed in five LQTS patients who had a history of syncope. The patients’ 12-lead and 24-h Holter monitoring ECG was

Cuilan Li; Dayi Hu; Lihua Shang; Shan Ma; Wenling Liu; Yuntian Li; Zhimin Ma; Chuzhong Tang; Yunqing Mei; Lexin Wang

2005-01-01

262

Evaluation of a Neyman-Pearson heart-rate turbulence detector  

Microsoft Academic Search

In this paper we propose and evaluate a Neyman-Pearson approach to detect and characterize heart-rate turbulence after ventricular premature beats (VPB). For quantification of the detection performance an evaluation dataset was built based on real RR interval series. The ROC curves obtained from the test set show the proposed method to outperform the detection capability of the two parameters currently

Juan Pablo Martinez; Pablo Laguna; Kristian Solem; Leif Sornmo

2008-01-01

263

Detection of atrial fibrillation episodes using multiple heart rate variability features in different time periods  

Microsoft Academic Search

Circadian variations of cardiac diseases have been well known. For example, atrial fibrillation (AF) episodes show nocturnal predominance. In this study, we have developed multiple formulas that detect AF episodes in different times of the day. Heart rate variability features were calculated from randomly sampled three min ECG data. Logistic regression analyses were performed to generate three formulas for the

Desok Kim; Yunhwan Seo; Chan Hyun Youn

2008-01-01

264

Reduction in extracellular muscle volume increases heart rate and blood pressure response to isometric exercise  

Microsoft Academic Search

Summary  To investigate the effect of local dehydration on heart rate and blood pressure during static exercise, six healthy male subjects performed exercise of the calf muscles with different extracellular volumes of the working muscles. Exercise consisted of 5 min of static calf muscle contractions at about 10% of maximal voluntary contraction. The body position during exercise was identical in all

K. Baum; D. Essfeld; J. Stegemann

1990-01-01

265

Analysis of twenty-four hour heart rate variability in patients with panic disorder  

Microsoft Academic Search

Growing evidence suggests that alterations in autonomic function contribute to the pathophysiology of panic disorder (PD). This retrospective study employed 24-h heart rate variability (HRV) analysis of Holter records to compare autonomic function in PD patients (n=38) with healthy, age- and gender-matched controls. Both time and frequency domain measures were calculated, and a circadian rhythm analysis was performed. The SDNN

Rollin McCraty; Mike Atkinson; Dana Tomasino; William P. Stuppy

2001-01-01

266

Heart rate patterns in sedentary shift work: influence of circadian rhythm, meals and personality  

Microsoft Academic Search

Heart rate was recorded at regular intervals during the course of 8-h sessions of simulated sedentary shift work performed for 12 consecutive days. Separate groups of subjects were assigned to one of three shifts, commencing either at 0400 hours (“morning” shift), 0800 hours (“day” shift) or 2200 hours (“night” shift). A major meal was taken during a break in the

W. P. Colquhoun

1988-01-01

267

Systolic function, readmission rates, and survival among consecutively hospitalized patients with congestive heart failure  

Microsoft Academic Search

We sought to describe the relation between left ventricular systolic function and rates of hospital readmission and survival among consecutively hospitalized patients with congestive heart failure. Medical records were reviewed for these patients at an academic medical center between Jan. 1, 1992, and Dec. 31, 1993. Left ventricular systolic function assessments performed within 6 months before discharge were used to

Mary McGrae McDermott; Joe Feinglass; Peter I. Lee; Shruti Mehta; Brian Schmitt; Frank Lefevre; Mihai Gheorghiade

1997-01-01

268

Heart rate changes during partial seizures: A study amongst Singaporean patients  

Microsoft Academic Search

INTRODUCTION: Studies in Europe and America showed that tachycardia, less often bradycardia, frequently accompanied partial seizures in Caucasian patients. We determine frequency, magnitude and type of ictal heart rate changes during partial seizures in non-Caucasian patients in Singapore. METHODS: Partial seizures recorded during routine EEGs performed in a tertiary hospital between 1995 and 1999 were retrospectively reviewed. All routine EEGs

Einar Wilder-Smith; Shih-Hui Lim

2001-01-01

269

Influence of vagal activity on classically conditioned heart rate in rats  

Microsoft Academic Search

Examined the relative contributions of parasympathetic and sympathetic activity in controlling classically conditioned heart rate (HR) in 112 female Long-Evans rats in a 2 * 2 * 2 factorial design involving comparisons of the following factors: (a) conditioning vs sensitization, (b) vagal blockade vs nonblockade, and (c) acquisition vs extinction. Vagal blockade led to a substantial reduction in the performance

Robert D. Fitzgerald; Glen K. Martin; James H. OBrien

1973-01-01

270

Multifractal heart rate dynamics in human cardiovascular model  

NASA Astrophysics Data System (ADS)

Human cardiovascular and/or cardio-respiratory systems are shown to exhibit both multifractal and synchronous dynamics, and we recently developed a nonlinear, physiologically plausible model for the synchronization between heartbeat and respiration (Kotani, et al. Phys. Rev. E 65: 051923, 2002). By using the same model, we now show the multifractality in the heart rate dynamics. We find that beat-to-beat monofractal noise (fractional Brownian motion) added to the brain stem cardiovascular areas results in significantly broader singularity spectra for heart rate through interactions between sympathetic and parasympathetic nervous systems. We conclude that the model proposed here would be useful in studying the complex cardiovascular and/or cardio- respiratory dynamics in humans.

Kotani, Kiyoshi; Takamasu, Kiyoshi; Safonov, Leonid; Yamamoto, Yoshiharu

2003-05-01

271

Heart rate recovery following maximal arm and leg-ergometry  

Microsoft Academic Search

Introduction  Different exercise modes result in different heart rate recovery (HRR) patterns which could be related to the greater vagal\\u000a reactivation following arm compared to leg-ergometry.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Heart rate recovery was calculated following maximal arm and leg-ergometry.\\u000a \\u000a \\u000a \\u000a Results  HRR-1 following maximal arm-ergometry was significantly higher than HRR-1 post maximal and sub-maximal leg-ergometry.\\u000a \\u000a \\u000a \\u000a Conclusion  This may be of clinical significance to individuals relying on their

Sushant M. Ranadive; Christopher A. Fahs; Huimin Yan; Lindy M. Rossow; Stamatis Agliovlastis; Bo Fernhall

2011-01-01

272

Estimating mental fatigue based on electroencephalogram and heart rate variability  

NASA Astrophysics Data System (ADS)

The effects of long term mental arithmetic task on psychology are investigated by subjective self-reporting measures and action performance test. Based on electroencephalogram (EEG) and heart rate variability (HRV), the impacts of prolonged cognitive activity on central nervous system and autonomic nervous system are observed and analyzed. Wavelet packet parameters of EEG and power spectral indices of HRV are combined to estimate the change of mental fatigue. Then wavelet packet parameters of EEG which change significantly are extracted as the features of brain activity in different mental fatigue state, support vector machine (SVM) algorithm is applied to differentiate two mental fatigue states. The experimental results show that long term mental arithmetic task induces the mental fatigue. The wavelet packet parameters of EEG and power spectral indices of HRV are strongly correlated with mental fatigue. The predominant activity of autonomic nervous system of subjects turns to the sympathetic activity from parasympathetic activity after the task. Moreover, the slow waves of EEG increase, the fast waves of EEG and the degree of disorder of brain decrease compared with the pre-task. The SVM algorithm can effectively differentiate two mental fatigue states, which achieves the maximum classification accuracy (91%). The SVM algorithm could be a promising tool for the evaluation of mental fatigue. Fatigue, especially mental fatigue, is a common phenomenon in modern life, is a persistent occupational hazard for professional. Mental fatigue is usually accompanied with a sense of weariness, reduced alertness, and reduced mental performance, which would lead the accidents in life, decrease productivity in workplace and harm the health. Therefore, the evaluation of mental fatigue is important for the occupational risk protection, productivity, and occupational health.

Zhang, Chong; Yu, Xiaolin

2010-01-01

273

Fetal heart rate pattern and risk for respiratory disturbance in full-term newborns.  

PubMed

Etiologic and pathogenetic factors responsible for respiratory disturbances in full-term infants are still unclear. The authors' intention was to analyze to what extent fetal stress, expressed in terms of abnormal fetal heart rate pattern, was reflected in neonatal respiratory disturbance. The study was performed prospectively over one year and included 157 term infants. Contrary to general belief, there was a significantly lower incidence of respiratory disturbances after ominous fetal heart rate pattern, ie, basal bradycardia, late or severe variable decelerations, and reduced variability than after a normal fetal heart rate pattern. It is suggested that these results may be due to a favorable effect on the fetal lung of systemic or local factors, produced in response to intrauterine stress. PMID:3725259

Wennergren, M; Krantz, M; Hjalmarson, O; Karlsson, K

1986-07-01

274

Developmental change in intentional action and inhibition: a heart rate analysis.  

PubMed

The ability to inhibit is a major developmental dimension. Previous studies examined developmental change in instructed inhibition. The current study, however, focused on intentional inhibition. We examined heart rate responses to intentional action and inhibition, with a focus on developmental differences. Three age groups (8-10, 11-12, and 18-26 years) performed a child-friendly marble paradigm in which they had to choose between intentionally acting on, or inhibiting, a prepotent response. As instructed, all age groups chose to intentionally inhibit on approximately 50 percent of the intentional trials. A pronounced heart rate deceleration was observed during both intentional action and intentional inhibition, but this deceleration was most pronounced for intentional inhibition. Heart rate responses did not differentiate between age groups, suggesting that intentional action and inhibition reach mature levels early in childhood. PMID:23718701

Schel, Margot A; Windhorst, Dafna A; van der Molen, Maurits W; Crone, Eveline A

2013-05-30

275

Heart Rate Variability and Disease Characteristics in Patients with COPD  

Microsoft Academic Search

Heart rate variability (HRV) is reduced in patients with chronic obstructive pulmonary disease (COPD). However, the relationships\\u000a among HRV and characteristics of COPD are unknown. The aim of this study was to characterize HRV in patients with COPD and\\u000a to verify the correlation of HRV measured during rest with disease severity and pulmonary, muscular, and functional impairment.\\u000a Thirty-one patients with

Carlos A. Camillo; Fabio Pitta; Heloíse V. Possani; Marcus V. R. A. Barbosa; Divina S. O. Marques; Vinícius Cavalheri; Vanessa S. Probst; Antonio F. Brunetto

2008-01-01

276

Risk Stratification After Acute Myocardial Infarction by Heart Rate Turbulence  

Microsoft Academic Search

Background—Retrospective postinfarction studies revealed that decreased heart rate turbulence (HRT) indicates increased risk for subsequent death. This is the first prospective study to validate HRT in a large cohort of the reperfusion era. Methods and Results—One thousand four hundred fifty-five survivors of an acute myocardial infarction (age 76 years) in sinus rhythm were enrolled. HRT onset (TO) and slope (TS)

Petra Barthel; Raphael Schneider; Axel Bauer; Kurt Ulm; Claus Schmitt; Albert Schömig; Georg Schmidt

2010-01-01

277

Heart rate reactivity in attention deficit disorder subgroups  

Microsoft Academic Search

Beat-to-beat heart rate (HR) was analyzed for 9 contiguous seconds in a warned reaction time (RT) paradigm. Imperative stimuli were tones of three\\u000a intensity levels (55, 78, and 100 db); a visual warning signal occurred 5 sec before tone onset. Baseline and reward conditions\\u000a were run. Normal controls were contrasted with three Attention Deficit Disorder (ADD) subgroups: ADD-only, ADD with

Roscoe A. Dykman; Peggy T. Ackerman; D. Michael Oglesby

1992-01-01

278

Heart rate and ventilatory frequency as dimension-dependent variables  

Microsoft Academic Search

Summary  Heart rate (HR) and ventilatory frequency (f) were determined at rest in 79 boys and 91 girls aged 0.07–20 years and with a range in heights from 54–198 cm to establish the relationship between decrease in HR and f during early life with increase in body dimensions. From theoretical considerations it is assumed that frequencies such as HR and f

Erling Asmussen; N. H. Secher; E. A. Andersen

1981-01-01

279

Ovulation and equine body temperature and heart rate circadian rhythms  

Microsoft Academic Search

Deep body temperature (DBT) and heart rate (HR) circadian rhythms were determined by radiotelemetry in 4 mares kept under controlled light and temperature conditions. Ovulations were determined by rectal palpation of their ovaries. Mean DBT values ranged from 35.85 ± .04 to 37.22 ± .02°C The circadian range of oscillation was extremely low, approximately 0.5° C, with time of maximum

J. W. Evans; C. M. Winget; C. De Roshia; D. C. Holley

1976-01-01

280

Reduced serotonergic functioning changes heart rate in ADHD  

Microsoft Academic Search

Reduced mean heart rate (HR) was shown to be a biophysiological marker for aggression, which in turn was proven to be related\\u000a to changed serotonergic neurotransmission. A total of 16 ADHD-diagnosed boys were subjected to rapid tryptophan depletion\\u000a (RTD) and a placebo in a double-blind within-subject crossover-design. Mean HR was assessed under RTD\\/placebo. Low impulsive\\u000a patients behaving aggressively under RTD

Florian Daniel Zepf; M. Holtmann; C. Stadler; L. Wöckel; F. Poustka

2009-01-01

281

Heart-Rate responses (HRR) to lateralized visual stimuli  

Microsoft Academic Search

Direction of changes in heart-rate responses (HRR) were investigated in three separate experiments as a measure of differential\\u000a cognitive and emotional specialization of the cerebral hemispheres. Visual stimuli were presented via the visual half-field\\u000a technique in all three experiments. Slides with different contents were flashed for 200 msec on each trial either to the left\\u000a or right of a center

Kenneth Hugdahl; Mikael Franzon; Britta Andersson; Gunilla Walldebo

1983-01-01

282

The effects of hypnosis on heart rate variability.  

PubMed

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

283

Cholesterol enhances classical conditioning of the rabbit heart rate response  

PubMed Central

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

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

2007-01-01

284

Time-domain system for assessing variation in heart rate  

Microsoft Academic Search

The paper presents an alternative to Fourier techniques for assessment of heart rate variation. The system operates on R-R\\u000a interval data (intervals between successive R-waves of an ECG). Artefacts are first detected and corrected by recombination\\u000a of deviant intervals. Next, the highest frequency variation is recognised by identifying changes in the sign of the slope\\u000a of successive R-R intervals as

V. L. Schechtman; K. A. Kluge; R. M. Harper

1988-01-01

285

The effect of cigarette smoking on fetal heart rate characteristics  

Microsoft Academic Search

OBJECTIVE:To evaluate the effect of repeated cigarette smoking on fetal heart rate (FHR) characteristics.METHODS:Fifteen chronic smokers who were between 28 and 36 weeks’ gestation were evaluated during an 8-hour smoking session. Baseline FHR and reactivity were evaluated before an initial cigarette and 4 hours later (after the fourth cigarette), when the effects of smoking on FHR were expected to be

Cheryl Oncken; Henry Kranzler; Paulette O’Malley; Paula Gendreau; Winston A Campbell

2002-01-01

286

Orthostatic heart rate responses after prolonged space flights  

Microsoft Academic Search

Orthostatic tachycardia (POTS) can occur after space flights. We determined orthostatic heart rate responses in 18 cosmonauts\\u000a before and 3–5 days after long-term space missions. Cosmonauts undergoing a cardiovascular training program in space experienced\\u000a only moderate POTS after their return to earth. Cardiovascular countermeasures may have attenuated POTS. Another possible\\u000a interpretation is that cardiovascular deconditioning is not sufficient to elicit full

Jens TankRoman; Roman M. Baevsky; Irina I. Funtova; André Diedrich; Irina N. Slepchenkova; Jens Jordan

2011-01-01

287

Relationship of Heart Rate Variability to Parasympathetic Effect  

Microsoft Academic Search

Background—Baroreflex-mediated parasympathetic stimulation has variable effects on heart rate variability (HRV). We postulated that a quadratic function would describe the relationship between HRV and parasympathetic effect better than a linear function. Methods and Results—Twenty-nine normal volunteers (15 women; mean age 39 612 years) were studied after b-adrenergic blockade with intravenous propranolol. Five-minute ECG recordings were made during graded infusions of

Jeffrey J. Goldberger; Sridevi Challapalli; Roderick Tung; Michele A. Parker; Alan H. Kadish

2010-01-01

288

The Effect of Chorionic Villus Sampling on Fetal Heart Rate  

Microsoft Academic Search

Objective: Fetal heart rate (FHR) variation during chorionic villus sampling (CVS) is a controversial topic. Limited studies have been published on this subject. Our study intended to evaluate the effects of CVS on the FHR. Method: One hundred and sixty-five patients undergoing first-trimester elective CVS for prenatal diagnosis of ?-thalassemia were entered into a prospective study. M-mode FHR was obtained

Shahram Akhlaghpoor; Taraneh Hosseinipoor

2005-01-01

289

Threshold modeling of autonomic control of heart rate variability.  

PubMed

Even in the absence of external perturbation to the human cardiovascular system, measures of cardiac function, such as heart rate, vary with time in normal physiology. The primary source of the variation is constant regulation by a complex control system which modulates cardiac function through the autonomic nervous system. Here, we present methods of characterizing the statistical properties of the underlying processes that result in variations in ECG R-wave event times within the framework of an integrate-and-fire model. We first present techniques for characterizing the noise processes that result in heart rate variability even in the absence of autonomic input. A relationship is derived that relates the spectrum of R-R intervals to the spectrum of the underlying noise process. We then develop a technique for the characterization of the dynamic nature of autonomically related variability resulting from exogenous inputs, such as respiratory-related modulation. A method is presented for the estimation of the transfer function that relates the respiratory-related input to the variations in R-wave event times. The result is a very direct analysis of autonomic control of heart rate variability through noninvasive measures, which provides a method for assessing autonomic function in normal and pathological states. PMID:11008415

Stanley, G B; Poolla, K; Siegel, R A

2000-09-01

290

Experimental heart rate regulation in cycle-ergometer exercises.  

PubMed

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. PMID:23086500

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

2012-10-16

291

Target Dyspnea Ratings Predict Expected Oxygen Consumption as Well as Target Heart Rate Values  

Microsoft Academic Search

A target heart rate (THR) is the traditional method to prescribe and monitor exercise training inten- sity in healthy individuals. However, patients with chronic obstructive pulmonary disease (COPD) are limited by ventilatory impairment and dyspnea rather than cardiovascular factors. An alternative ap- proach is to use dyspnea ratings as a target for exercise training in patients with respiratory disease just

ROBERTO MEJIA; JOSEPH WARD; TIMOTHY LENTINE; DONALD A. MAHLER

1999-01-01

292

Catecholamine-Independent Heart Rate Increases Require CaMKII  

PubMed Central

Background Catecholamines increase heart rate by augmenting the cAMP responsive HCN4 ‘pacemaker current’ (If) and/or by promoting inward Na+/Ca2+ exchanger current (INCX), by a ‘Ca2+ clock’ mechanism in sinoatrial nodal cells (SANCs). The importance, identity and function of signals that connect If and Ca2+ clock mechanisms are uncertain and controversial, but the multifunctional Ca2+ and calmodulin-dependent protein kinase II (CaMKII) is required for physiological heart rate responses to ?-adrenergic receptor (?-AR) stimulation. The aim of this stuy is to measure the contribution of the Ca2+ clock and CaMKII to cardiac pacing independent of ?-AR agonist stimulation. Methods and Results We used the L-type Ca2+ channel agonist BayK 8644 (BayK) to activate the SANC Ca2+ clock. BayK and isoproterenol were similarly effective in increasing rates in SANCs and Langendorff-perfused hearts from WT control mice. In contrast, SANCs and isolated hearts from mice with CaMKII inhibition by transgenic expression of an inhibitory peptide (AC3-I) were resistant to rate increases by BayK. BayK only activated CaMKII in control SANCs, but increased ICa equally in all SANCs, indicating that increasing ICa was insufficient and suggesting CaMKII activation was required for heart rate increases by BayK. BayK did not increase If or protein kinase A (PKA)-dependent phosphorylation of phospholamban (at Ser16), indicating that increased SANC Ca2+ by BayK did not augment cAMP/PKA signaling at these targets. Late diastolic intracellular Ca2+ release and INCX were significantly reduced in AC3-I SANCs and the response to BayK was eliminated by ryanodine in all groups. Conclusions The Ca2+ clock is capable of supporting physiological fight or flight responses, independent of ?-AR stimulation or If increases. Complete Ca2+ clock and ?-AR stimulation responses require CaMKII.

Gao, Zhan; Singh, Madhu V; Hall, Duane D; Koval, Olha M.; Luczak, Elizabeth D.; Joiner, Mei-ling A.; Chen, Biyi; Wu, Yuejin; Chaudhary, Ashok K; Martins, James B; Hund, Thomas J; Mohler, Peter J; Song, Long-Sheng; Anderson, Mark E.

2011-01-01

293

Heart-rate reactivity to cold pressor stress following biofeedback training  

Microsoft Academic Search

Three previous studies have shown that biofeedback training is useful in modifying heart-rate and pain ratings during ice water stimulation (cold pressor test). Subjects were given an initial cold pressor followed by heart-rate biofeedback training and a final cold pressor test in which they were instructed to control their heart rate in accordance with the prior training. It was assumed

John L. Reeves; David Shapiro

1983-01-01

294

The effect of long-term bradycardia on heart microvascular supply and performance.  

PubMed

Bradycardia has been shown to be beneficial for the normal and ischaemic heart because it improves diastolic perfusion and oxygen supply demand balance. Experimentally, a chronically induced decrease in heart rate, either by electrical pacing or pharmacological means, was found previously to increase myocardial capillary supply in normal rabbit and rat hearts. These studies have been extended to a larger mammal, the pig, in which a direct bradycardia (approximately 30% decrease in heart rate) was induced by electrical pacing for 4-5 weeks. There was no evidence of heart hypertrophy and capillary density was found to be significantly increased in the left, but not right, ventricle. Cardiac function during dobutamine inotropic challenge was better in pig hearts which had been paced bradycardially. They performed greater stroke work-higher stroke flow output at lower heart rate--for similar coronary blood flow, thus demonstrating an improved economy of flow utilisation. Heart rate reduction may facilitate capillary growth in the absence of cardiac hypertrophy by prolonging diastolic perfusion, and/or mechanical stretch of vessels due to increased stroke volume capacity. In either case, capillaries would be exposed to increased wall tension which could trigger angiogenesis. PMID:7531559

Brown, M D; Davies, M K; Hudlicka, O

1994-01-01

295

Genetic locus on mouse chromosome 7 controls elevated heart rate  

PubMed Central

Elevated heart rate (HR) is a risk factor for cardiovascular diseases. The goal of the study was to map HR trait in mice using quantitative trait locus (QTL) analysis followed by genome-wide association (GWA) analysis. The first approach provides mapping power and the second increases genome resolution. QTL analyses were performed in a C3HeB×SJL backcross. HR and systolic blood pressure (SBP) were measured by the tail-cuff plethysmography. HR was ?80 beats/min higher in SJL compared with C3HeB. There was a wide distribution of the HR (536–763 beats/min) in N2 mice. We discovered a highly significant QTL (logarithm of odds = 6.7, P < 0.001) on chromosome 7 (41 cM) for HR in the C3HeB×SJL backcross. In the Hybrid Mouse Diversity Panel (58 strains, n = 5–6/strain) we found that HR (beats/min) ranged from 546 ± 12 in C58/J to 717 ± 7 in MA/MyJ mice. SBP (mmHg) ranged from 99 ± 6 in strain I/LnJ to 151 ± 4 in strain BXA4/PgnJ. GWA analyses were done using the HMDP, which revealed a locus (64.2–65.1 Mb) on chromosome 7 that colocalized with the QTL for elevated HR found in the C3HeB×SJL backcross. The peak association was observed for 17 SNPs that are localized within three GABAA receptor genes. In summary, we used a combined genetic approach to fine map a novel elevated HR locus on mouse chromosome 7.

Smolock, Elaine M.; Ilyushkina, Irina A.; Ghazalpour, Anatole; Gerloff, Janice; Murashev, Arkady N.; Lusis, Aldons J.

2012-01-01

296

Muscle metaboreflex and autonomic regulation of heart rate in humans.  

PubMed

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). The magnitude of this increase in HR was similar with parasympathetic blockade (11 ± 2 beats min(-1)), but attenuated with ?-adrenergic blockade (4 ± 1 beats min(-1); P < 0.05 vs. control and parasympathetic blockade). During PEI following leg cycling exercise, HR remained similarly elevated above rest under all conditions (11 ± 2, 13 ± 3 and 9 ± 4 beats min(-1), for control, ?-adrenergic and parasympathetic blockade; 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

297

Heart rate variability and disease characteristics in patients with COPD.  

PubMed

Heart rate variability (HRV) is reduced in patients with chronic obstructive pulmonary disease (COPD). However, the relationships among HRV and characteristics of COPD are unknown. The aim of this study was to characterize HRV in patients with COPD and to verify the correlation of HRV measured during rest with disease severity and pulmonary, muscular, and functional impairment. Thirty-one patients with COPD (16 male; 66 +/- 8 years; BMI = 24 +/- 6 kg/m(2); FEV(1) = 46 +/- 16% predicted) without severe cardiac dysfunction were included. HRV assessment was performed by the head-up tilt test (HUTT), and the main variables used for analysis were SDNN index, LF/HF ratio, and R-R intervals. Other tests included spirometry, bioelectrical impedance, cardiopulmonary exercise test, 6-minute walk test, respiratory and peripheral muscle force, health-related quality of life and functional status questionnaires, and objective quantification of physical activity level in daily life with the DynaPort and SenseWear armband activity monitors, besides calculation of the BODE index. There was a statistical difference in all variables of HRV between the HUTT positions (lying and standing). There was no correlation of HRV with BODE index or FEV(1). Out of the BODE index, just the BMI was correlated with SDNN and R-R intervals (r = 0.44; p < 0.05 and r = 0.37; p < 0.05, respectively). There was correlation between HRV reduction and a lower level of physical activity in daily life, besides worse health-related quality of life, functional status, and respiratory and peripheral muscle force. Cardiac autonomic function of patients with COPD is not related to disease severity but mainly to the level of physical activity in daily life. PMID:18815834

Camillo, Carlos A; Pitta, Fabio; Possani, Heloíse V; Barbosa, Marcus V R A; Marques, Divina S O; Cavalheri, Vinícius; Probst, Vanessa S; Brunetto, Antonio F

2008-09-25

298

Analysis of heart rate variability using fuzzy measure entropy.  

PubMed

This paper proposed a new entropy measure, Fuzzy Measure Entropy (FuzzyMEn), for the analysis of heart rate variability (HRV) signals. FuzzyMEn was calculated based on the fuzzy set theory and improved the poor statistical stability in the approximate entropy (ApEn) and sample entropy (SampEn). The simulation results also demonstrated that the FuzzyMEn had better algorithm discrimination ability when compared with the recently published fuzzy entropy (FuzzyEn), The validity of FuzzyMEn was tested for clinical HRV analysis on 120 subjects (60 heart failure and 60 healthy control subjects). It is concluded that FuzzyMEn could be considered as a valid and reliable method for a clinical HRV application. PMID:23273774

Liu, Chengyu; Li, Ke; Zhao, Lina; Liu, Feng; Zheng, Dingchang; Liu, Changchun; Liu, Shutang

2012-12-27

299

Meta-analysis: Blocker Dose, Heart Rate Reduction, and Death in Patients With Heart Failure  

Microsoft Academic Search

Data Extraction: Two reviewers independently extracted data on study characteristics, -blocker dosing and heart rate reduction, and death. Data Synthesis: The mean left ventricular ejection fraction in the 23 -blocker trials ranged from 0.17 to 0.36, and more than 95% of the 19 209 patients had systolic dysfunction. The overall risk ratio for death was 0.76 (95% CI, 0.68 to

Finlay A. McAlister; Natasha Wiebe; Justin A. Ezekowitz; Alexander A. Leung; Paul W. Armstrong

2009-01-01

300

The relationships among heart rate variability, inflammatory markers and depression in coronary heart disease patients  

Microsoft Academic Search

Studies show negative correlations between heart rate variability (HRV) and inflammatory markers. In cardiac patients, depression is related to both. We investigated links between short-term HRV and inflammatory markers in relation to depression in acute coronary syndrome (ACS) patients.We measured C-reactive protein (CRP), interleukin-6 (IL-6), depression symptoms (Beck Depression Inventory, BDI-II), and SDNN, high frequency (HF) and low frequency (LF)

Nancy Frasure-Smith; François Lespérance; Michael R. Irwin; Mario Talajic; Bruce G. Pollock

2009-01-01

301

Influence of high-frequency bandwidth on heart rate variability analysis during physical exercise  

Microsoft Academic Search

Heart rate variability (HRV) analysis of beat-to-beat RR interval data was performed in 11 asymptomatic young male subjects during a progressive bicycle exercise test. RR interval data (Polar S810) and breath-by-breath respiratory data (rate, minute ventilation and oxygen uptake) (Oxycon Pro) were simultaneously recorded throughout exercise. ‘Ventilation per second’ was defined as V?Esec, the change (from the previous epoch) in

M. J. Lewis; M. Kingsley; A. L. Short; K. Simpson

2007-01-01

302

Terminology and Methodology Related to the Use of Heart Rate Responsivity in Infancy Research  

ERIC Educational Resources Information Center

Methodological problems in measuring and interpreting infantile heart rate reactivity in research are discussed. Various ways of describing cardiac activity are listed. Attention is given to the relationship between resting state and heart rate responsivity. (Author/WY)

Woodcock, James M.

1971-01-01

303

Nonlinear Systems Dynamics in Cardiovascular Physiology: The Heart Rate Delay MAP and Lower Body Negative Pressure.  

National Technical Information Service (NTIS)

A preliminary study of the applicability of nonlinear dynamic systems analysis techniques to low body negative pressure (LBNP) studies. In particular, the applicability of the heart rate delay map is investigated. It is suggested that the heart rate delay...

J. C. Hooker

1990-01-01

304

The loss of circadian heart rate variations in patients undergoing mitral valve replacement and Corridor procedure--comparison to heart transplant patients.  

PubMed

We have presently demonstrated that when added to mitral valve replacement (MVR) the corridor procedure is 75% efficient in restoring and maintaining sinus rhythm in patients with chronic atrial fibrillation (AF), caused by rheumatic mitral valve disease, (follow up 13.9months). In the same patient population, we observed that the typical day-night cycle heart rate (HR) variations were lost and our present study concentrates on this subject. Heart rate variability analysis based on 24-h Holter ECG recording (StrataScan 563 DelMar Avionics) or hospital discharge (12th-14th postoperative days) was performed in 3 patient groups: Group I: Patients with a Corridor procedure added to MVR (12pts, m/f 10/2, mean age 47.3+/-7.5yr); Group II (control): with patients MVR performed through the left atrial approach, without additional antiarrhythmic procedures (10pts, m/f 3/7 mean age 51.5+/-6.7yr), and Group III: heart transplant recipients (5pts, mean age 46.4+/-11.22yr). We analyzed the hourly heart rate over 24-h period divided into three 8-h segments (07-14h; 15-22h and 23-06h). Statistical comparison of mean hourly heart rate values was made between the three time periods of Holter monitoring. The Corridor procedure performed with mitral valve replacement resulted in conversion of sinus rhythm in 75% of patients (Group I), but postoperative heart rate variability analyses based on Holter monitoring disclosed that the mean heart rate was not statistically significantly difficult between the three 8-h segments of the day-night (P>0.05). The same results were found in the group of patients after heart transplant (P>0.05). The same results were found in the group of patients after heart transplant (P>0.05). In the second group (classical MVR), statistically significant differences in mean HR variation existed between the three 8-h intervals (P<0.05), and although atrial fibrillation occurred postoperatively physiologic circadian heart rate variations were preserved. With the Corridor procedure, both atria were surgically and electrically isolated and chronotropic function of the ventricles was restored by creating a small strip of atrial tissue with isolated sinus node and atrio-ventricular node, connected to the ventricles. This technique produced heart denervation nervous system influence, producing the loss of circadian HR variations, similar to the transplanted heart. PMID:11137811

Velimirovic, D B; Pavlovic, S U; Petrovic, P; Neskovic, A; Zivkovic, M; Bojic, M

2001-02-01

305

5 CFR 430.308 - Rating performance.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Rating performance. 430.308 Section 430.308 Administrative...MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT Managing Senior Executive Performance § 430.308 Rating...

2013-01-01

306

Deceleration capacity of heart rate as a predictor of mortality after myocardial infarction: cohort study  

Microsoft Academic Search

Background Decreased vagal activity after myocardial infarction results in reduced heart-rate variability and increased risk of death. To distinguish between vagal and sympathetic factors that aff ect heart-rate variability, we used a signal- processing algorithm to separately characterise deceleration and acceleration of heart rate. We postulated that diminished deceleration-related modulation of heart rate is an important prognostic marker. Our prospective

Axel Bauer; Jan W Kantelhardt; Petra Barthel; Raphael Schneider; Timo Mäkikallio; Kurt Ulm; Katerina Hnatkova; Albert Schömig; Heikki Huikuri; Armin Bunde; Marek Malik; Georg Schmidt

2006-01-01

307

Correlation of heart rate and radionuclide index of left ventricular contraction and relaxation  

Microsoft Academic Search

Since the cardiac function indices derived from radionuclide ventriculography (RNV) are considered to depend on the heart\\u000a rate, we studied the relationship between systolic or diastolic indices and heart rates in patients with normal RNV and devised\\u000a a method of correcting these indices according to the heart rate.\\u000a \\u000a For the systolic indices, the heart rate showed significant correlation with ET

Haruhiko Adachi; Hiroki Sugihara; Hiroaki Nakagawa; Suetsugu Inagaki; Yasushi Kubota; Masao Nakagawa

1990-01-01

308

Heart rate and physical activity patterns in persons with profound intellectual and multiple disabilities.  

PubMed

Waninge, A, van der Putten, AAJ, Stewart, RE, Steenbergen, B, Van Wijck, R, and van der Schans, CP. Heart rate and physical activity patterns in persons with profound intellectual and multiple disabilities. J Strength Cond Res 27(11): 3150-3158, 2013-Because physical fitness and health are related to physical activity, it is important to gain an insight into the physical activity levels of persons with profound intellectual and multiple disabilities (PIMD). The purpose of this study was to examine heart rate patterns to measure the activity levels of persons with PIMD and to analyze these heart rate patterns according to participant characteristics, observed level of activity, days, and time of day. The heart rate patterns of 24 participants with PIMD were measured continuously using a heart rate monitor for 8 h·d for a period of 6 days. Physical activity levels were measured with questionnaires. Data were analyzed using multilevel analysis. The results indicate that the participants use only 32% of their heart rate reserve over 6 days. The intensity of heart rate reserve ranged from 1 to 62%. On a given day, wide ranges in heart rates between participants and within persons were observed. Between days, only small ranges in the heart rate were found. The participants could be grouped into 4 classes according to their heart rate. In addition, factors such as time of day, physical activity, and age are significantly related to heart rate patterns. In conclusion, this study is an important first step in exploring activity patterns based on heart rate patterns in persons with PIMD. The participants used relatively small fractions of their heart rate reserves. Time of day and age appear to have a considerable influence on heart rate patterns. The observed classes in heart rate patterns suggest that other probably more personal and psychosocial factors have significant influences on heart rate patterns, as well. PMID:23442278

Waninge, Aly; van der Putten, Annette A J; Stewart, Roy E; Steenbergen, Bert; van Wijck, Ruud; van der Schans, Cees P

2013-11-01

309

Acute effects of alinidine on heart rate and blood pressure in healthy subjects and patients with hyperkinetic heart syndrome  

Microsoft Academic Search

The effects of a single dose of alinidine (0.5 mg\\/kg i.v.), the N-allyl-derivative of clonidine, on heart rate and blood pressure were investigated in healthy volunteers and in patients with hyperkinetic heart syndrome, at rest and during bicycle exercise. In healthy volunteers plasma catecholamine levels were also determined. Alinidine did not change heart rate at rest in the healthy volunteers

B. Stanek; W. Reiterer; P. Placheta; G. Raberger

1983-01-01

310

Resting Heart Rate and Outcomes in Patients with Cardiovascular Disease: Where Do We Currently Stand?  

PubMed Central

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, Ian BA; Davies, Simon; Gupta, Sandeep; Kalra, Paul R; Lang, Chim C; Morley, Chris; Padmanabhan, Sandosh

2013-01-01

311

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

PubMed

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

312

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

PubMed

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

313

Heart rate analysis in 24 patients treated with 150 mg amitriptyline per day  

Microsoft Academic Search

Twenty-four patients treated with 150 mg amitriptyline per day for an episode of major depression underwent a standardized heart rate analysis (HRA) before therapy and after 14 days. The battery of cardiovascular reflex tests included the determination of the coefficient of variation (CV) while resting and during deep respiration, a spectral analysis of heart rate, the heart rate response to

Thomas Rechlin; Detlef Claus; Maria Weis

1994-01-01

314

Has Non-linear Analysis of Heart Rate Variability Any Practical Value?  

Microsoft Academic Search

In this article, we focus on the recent advances in the assessment of the heart rate variability (HRV). Speci~cally, we review some of the new methods to assess heart rate dynamics based on non-linear mathematics and chaos theory. These methods do not quantify the actual magnitude of HRV but describe the complexity and dynamics of heart rate _uctuation. Although the

Antti E. Hedman; Juha E. K. Hartikainen

1999-01-01

315

Heart rate variability: Response to graded head up tilt in healthy men  

Microsoft Academic Search

Background: Heart rate variability is actually a misnomer for R to R variability in cardiac cycle. Variation in successive cycle length is called the heart rate variability (HRV). Head-up tilt is a model of studying cardiovascular haemodynamics, which refl ects in heart rate variability (HRV). Objectives: To study the effect of 10° and 70° head-up tilt on HRV. Materials and

Sharma P; Paudel BH; Singh PN; Limbu P

316

Resemblances of parents and twins in sports participation and heart rate  

Microsoft Academic Search

A model to analyze resemblances of twins and parents using LISREL is outlined and applied to sports participation and heart-rate data. Sports participation and heart rate were measured in 44 monozygotic and 46 dizygotic adolescent twin pairs and in their parents. Genetic factors influence variation in both sports behavior and heart rate, while there is no evidence for transmission from

D. I. Boomsma; M. B. M. van den Bree; J. F. Orlebeke; P. C. M. Molenaar

1989-01-01

317

A pharmacokinetic–pharmacodynamic model of heart rate during cocaine administration in humans  

Microsoft Academic Search

We developed a pharmacokinetic-pharmacodynamic model of the heart rate response to cocaine consisting of the sum of the baseline heart rate, a chronotropic drug effect, and a conditioned heart rate response. The conditioned response was modeled as having a monoexponential decline. Cocaine's chronotropic effect was modeled as obeying a maximum (Emax) drug-effect relationship without tachyphylaxis. The model was tested by

Dennis A Noe; Karen M Kumor

1991-01-01

318

Human Fetal Heart Rate Dishabituation between Thirty and Thirty-Two Weeks Gestation.  

ERIC Educational Resources Information Center

|Examined the ability of 32-week human fetuses to learn and recall information. Found a significant heart rate habituation pattern for a series of vibroacoustic stimuli. After a single novel stimulus, the heart rate to stimulus 1 reemerged. Uterine contractions were not related to presentation of the novel stimulus or change in heart rate after…

Sandman, Curt A.; Wadhwa, Pathik; Hetrick, William; Porto, Manuel; Peeke, Harmon V. S.

1997-01-01

319

Problem Behavior and Heart Rate Reactivity in Adopted Adolescents: Longitudinal and Concurrent Relations  

ERIC Educational Resources Information Center

|The present longitudinal study examined resting heart rate and heart rate variability and reactivity to a stressful gambling task in adopted adolescents with aggressive, delinquent, or internalizing behavior problems and adopted adolescents without behavior problems (total N=151). Early-onset delinquent adolescents showed heart rate

Bimmel, Nicole; van IJzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Juffer, Femmie; De Geus, Eco J. C.

2008-01-01

320

Early Childhood Heart Rate Does Not Predict Externalizing Behavior Problems at Age 7 Years  

Microsoft Academic Search

ObjectiveIn previous research, low resting heart rate in childhood and adolescence has been shown to predict aggressive and\\/or delinquent behavior at subsequent ages. It has been found that heart rate recorded as early as age 3 years could predict externalizing behavior at age 11 years. This study explored the possibility of a similar relationship between heart rate and externalizing behavior

CAROL A. VAN HULLE; ROBIN CORLEY; CAROLYN ZAHN-WAXLER; JEROME KAGAN; JOHN K. HEWITT

2000-01-01

321

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

ERIC Educational Resources Information Center

|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

322

Effect of ethanol of heart rate and blood pressure in nonstressed and stressed rats  

Microsoft Academic Search

The effect of ethanol on the cardiovascular system (ECG, heart rate, blood pressure) was studied in anesthetized, nonstressed or stressed rats. In anesthetized rats, ethanol showed no effect on heart rate or ECG. In nonstressed rats, ethanol sedated the animals but increased heart rate significantly. This ethanol induced tachycardia seemed the result of a direct stimulation of the sympathetic nerves

M. G. Sparrow; H. Roggendorf; W. H. Vogel

1987-01-01

323

The effect of artifact correction on spectral estimates of heart rate variability  

Microsoft Academic Search

Spectral analysis of fetal heart rate variability might offer additional information that can be used for assessing the fetal condition more reliably. Clinical recordings of fetal heart rate are usually contaminated by artifacts. These artifacts can be detected and corrected or removed, but this can affect the spectral estimates obtained from the heart rate data. To determine what level of

Chris Peters; Rik Vullings; Jan Bergmans; Guid Oei; Pieter Wijn

2008-01-01

324

Functional assessment of nutritional status: heart rate response to submaximal work1'2  

Microsoft Academic Search

The heart rate response to submaximal treadmill work has been calculated using the heart rates and oxygen intakes obtained from normally nourished and undernourished adult male subjects during a maximal oxygen consumption test. Increased severity of malnutrition was associated with an increased heart rate response to the same submaximal work loads. The response was observed to decrease during a period

G. B. Spurr; M. Barac-Nieto; M. G. Maksud

1979-01-01

325

A novel method to detect Heart Beat Rate using a mobile phone  

Microsoft Academic Search

Heart Beat Rate calculation has traditionally been conducted using specialized hardware most commonly in the form of pulse oximeters or Electrocardiogram devices. Even though these methods offer high reliability, they require the users to have special sensor to measure their heart rate. In this paper we propose a system capable of estimating the heart beat rate using just a camera

P. Pelegris; K. Banitsas; T. Orbach; K. Marias

2010-01-01

326

Heart rate change as evidence for vaginally elicited orgasm and orgasm intensity  

Microsoft Academic Search

The purposes of this study were a) to further replicate previous findings on vaginal eroticism, using heart rate change as corroborative evidence for the subjective perception of sexual arousal and orgasm; and b) to investigate the correlation between heart rate change and subjective intensity of female orgasm. Heart rate measurements were obtained from ECG tracings. Eleven coitally experienced volunteers were

Heli Alzate; Bernardo Useche; Magdalena Villegas

1989-01-01

327

The Relationship between Heart Rate Reserve and Oxygen Uptake Reserve in Children and Adolescents  

ERIC Educational Resources Information Center

|The purpose of the present study was to examine the relationship between oxygen uptake (VO[subscript 2]) and heart rate (HR) responses during rest and exercise in Chinese children and youth and to evaluate the relationships between maximal heart rate (%HRmax), heart rate reserve (%HRR), peak oxygen uptake (%VO[subscript 2]peak), and oxygen uptake…

Hui, Stanley Sai-chuen; Chan, Janus Wan-sze

2006-01-01

328

Elevated heart rate and atherosclerosis: An overview of the pathogenetic mechanisms  

Microsoft Academic Search

Several epidemiological studies have reported that an elevated heart rate is associated with coronary atherosclerosis independently of other risk factors. In this review we explore the pathophysiologic mechanisms involved in the pro-atherosclerotic effect of elevated heart rate, apart from its association with sympathetic tone. An elevated heart rate enhances the magnitude and frequency of the tensile stress imposed on the

George D. Giannoglou; Yiannis S. Chatzizisis; Chrysanthos Zamboulis; George E. Parcharidis; Dimitri P. Mikhailidis; George E. Louridas

2008-01-01

329

Genome-wide association analysis identifies multiple loci related to resting heart rate  

Microsoft Academic Search

Higher resting heart rate is associated with increased cardiovascular disease and mortality risk. Though heritable factors play a substantial role in population variation, little is known about specific genetic determinants. This knowledge can impact clinical care by identifying novel factors that influence pathologic heart rate states, modulate heart rate through cardiac structure and function or by improving our understanding of

Mark Eijgelsheim; Christopher Newton-Cheh; Nona Sotoodehnia; Bakker de P. I. W; M. Müller; Alanna C. Morrison; Albert V. Smith; Aaron Isaacs; Serena Sanna; M. Dörr; P. Navarro; C. Fuchsberger; I. M. Nolte; Geus de E. J. C; K. Estrada; S.-J. Hwang; J. C. Bis; I.-M. Ruckert; A. Alonso; L. J. Launer; J. J. Hottenga; F. Rivadeneira Ramirez; P. A. Noseworthy; T. A. Rice; S. Perz; D. E. Arking; T. D. Spector; J. A. Kors; Y. S. Aulchenko; K. V. Tarasov; G. Homuth; S. H. Wild; F. Marroni; C. Gieger; C. M. M. Licht; R. J. Prineas; A. Hofman; J. I. Rotter; A. A. Hicks; F. D. J. Ernst; S. S. Najjar; A. F. Wright; A. Peters; E. R. Fox; B. A. Oostra; H. K. Kroemer; D. J. Couper; H. Völzke; H. Campbell; T. Meitinger; M. Uda; J. C. M. Witteman; B. M. Psaty; H.-E. Wichmann; T. B. Harris; S. Kääb; D. S. Siscovick; Y. Jamshidi; A. G. Uitterlinden; A. R. Folsom; M. G. Larson; J. F. Wilson; B. W. J. H. Penninx; H. Snieder; P. P. Pramstaller; P. Tikka-Kleemola; E. G. Lakatta; S. B. Felix; V. Gudnason; A. Pfeufer; S. R. Heckbert; B. H. Ch. Stricker; E. Boerwinkle; C. J. O'Donnell

2010-01-01

330

Heart rate variability abnormalities in young patients with dilated cardiomyopathy.  

PubMed

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

331

Noisy fluctuation of heart rate indicates cardiovascular system instability.  

PubMed

Heart rate spontaneously fluctuates despite homeostatic regulatory mechanisms to stabilize it. Harmonic and fractal fluctuations have been described. Non-harmonic non-fractal fluctuation has not been studied because it is usually thought that it is caused by apparatus noise. We hypothesized that this fluctuation looking like apparatus noise (that we call "noisy fluctuation") is linked to challenged blood pressure stabilization and not to apparatus noise. We assessed noisy fluctuation by quantifying the small and fastest beat-to-beat fluctuation of RR-interval by means of spectral analysis (Nyquist power of heart rate variability: nyHRV) after filtering out its fractal component. We observed nyHRV in healthy supine subjects and in patients with vasovagal symptoms. We challenged stabilization of blood pressure by upright posture (by means of a head-up tilt table test). Head-up position on the tilt table dramatically decreased nyHRV (0.128 ± 0.063 vs. 0.004 ± 0.002, p < 0.01) in healthy subjects (n = 12). Head-up position also decreased nyHRV in patients without vasovagal symptoms (n = 24; 0.220 ± 0.058 vs. 0.034 ± 0.015, p < 0.05), but not in patients with vasovagal symptoms during a head-up tilt table test (age and sex paired, 0.103 ± 0.041 vs. 0.122 ± 0.069, not significant). Heart rate variability includes a physiological non-harmonic non-fractal noisy fluctuation. This noisy fluctuation indicates low engagement of regulatory mechanisms because it disappears when the cardiovascular system is challenged (upright posture). It also indicates cardiovascular instability because it does not disappear in upright patients before vasovagal syncope, a transient failure of cardiovascular regulation. PMID:23652709

Fortrat, Jacques-Olivier; Baum, Charlotte; Jeanguillaume, Christian; Custaud, Marc-Antoine

2013-05-08

332

Wireless patch sensor for remote monitoring of heart rate, respiration, activity, and falls.  

PubMed

Unobtrusive continuous monitoring of important vital signs and activity metrics has the potential to provide remote health monitoring, at-home screening, and rapid notification of critical events such as heart attacks, falls, or respiratory distress. This paper contains validation results of a wireless Bluetooth Low Energy (BLE) patch sensor consisting of two electrocardiography (ECG) electrodes, a microcontroller, a tri-axial accelerometer, and a BLE transceiver. The sensor measures heart rate, heart rate variability (HRV), respiratory rate, posture, steps, and falls and was evaluated on a total of 25 adult participants who performed breathing exercises, activities of daily living (ADLs), various stretches, stationary cycling, walking/running, and simulated falls. Compared to reference devices, the heart rate measurement had a mean absolute error (MAE) of less than 2 bpm, time-domain HRV measurements had an RMS error of less than 15 ms, respiratory rate had an MAE of 1.1 breaths per minute during metronome breathing, posture detection had an accuracy of over 95% in two of the three patch locations, steps were counted with an absolute error of less than 5%, and falls were detected with a sensitivity of 95.2% and specificity of 100%. PMID:24111135

Chan, Alexander M; Selvaraj, Nandakumar; Ferdosi, Nima; Narasimhan, Ravi

2013-07-01

333

Influence of heart rate on mortality after acute myocardial infarction.  

PubMed

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

334

Heart rate variability changes in physicians working on night call  

Microsoft Academic Search

Purpose  Adverse effects by night-call duty have become an important occupational health issue. The aim of this study was to investigate\\u000a whether the heart rate variability (HRV) differed during recovery from day work and night-call duty between distinct physician\\u000a specialities.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  We studied the impact of a 16-h night-call duty on autonomic balance, measured by HRV, among two physician groups differing\\u000a with

Birgitta Malmberg; Roger Persson; Per Flisberg; Palle Ørbaek

2011-01-01

335

Effects of autonomic blockade on nonlinear heart rate dynamics  

Microsoft Academic Search

Introduction  Analysis of nonlinear heart rate (HR) dynamics may provide greater insight into neurocardiac influences during exercise and\\u000a disease than traditional HR variability. However, the physiological basis of nonlinear HR dynamics has not been investigated\\u000a in individuals with spinal cord injury (SCI). The purpose of this study was to compare the effects of autonomic blockade in\\u000a SCI and able-bodied participants.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Five

Philip J. Millar; Lisa M. Cotie; Tim St. Amand; Neil McCartney; David S. Ditor

2010-01-01

336

Influence of Changes in Heart Rate, Aortic Pressure and Flow Rate upon Experimental Coronary Insufficiency  

Microsoft Academic Search

This study was designed to evaluate the role of heart rate, aortic pressure, and aortic flow in the development of coronary insufficiency following acute coronary stenosis. In dogs, each of these parameters was controlled at a predetermined level while the left anterior descending coronary artery was constricted with a small screw clamp. The critical coronary pressure (CCP), i.e. the pressure

Kunihiko Hirasawa; Tsuneaki Sugimoto; Tetsuo Nohara; Nobuo Ohya; Tohru Inasaka; Kensuke Kaseno; Jugoro Takeuchi

1974-01-01

337

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

PubMed

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

338

Predicting rate of oxygen consumption from heart rate while little penguins work, rest and play  

Microsoft Academic Search

The relationship between heart rate (fH) and rate of oxygen consumption (V?O2) was investigated under changing conditions of ambient temperature, digestive state and exercise state in the little penguin (Eudyptula minor). Both fH and V?O2 were recorded simultaneously from 12 little penguins while they each (a) rested and exercised within their reported thermo-neutral zone (TNZ), (b) rested and exercised below

J. A. Green; P. B. Frappell; T. D. Clark; P. J. Butler

2008-01-01

339

Patterns of heart rate responses to hydralazine in normotensive and hypertensive rats.  

PubMed

Hydralazine (H) induces hypotension accompanied by cardiac stimulation due to activation of the arterial baroreflex. Both clinical and experimental observations suggest, however, that in certain conditions H hypotension can be accompanied by unchanged or even depressed cardiac performance. The present study determined whether varying patterns of heart rate responses could be detected in large populations of conscious normotensive (n = 61) and renal hypertensive (n = 59) rats receiving a single dose of H. These patterns were compared with those of normotensive pentobarbital-anesthetized rats (n = 43). In the three groups, hypotension was accompanied by either tachycardia, unchanged heart rate or bradycardia. Tachycardia was found in 52% of normotensive conscious rats, in 51% of hypertensives and in only 14% of anesthetized animals. Heart rate did not change in 26, 35 and 23%, while bradycardia was detected in 22, 14 and 63%, respectively. These results were explained by postulating the initiation by H of two reflexes with opposite effects on heart rate: the arterial baroreflex producing tachycardia and a cardiac mechanoreceptor reflex producing bradycardia. These reactions would compete with each other, with results depending on their relative sensitivity in a given animal. PMID:8854385

Vidrio, H

1996-01-01

340

Increased Amygdala Activation is Related to Heart Rate During Emotion Processing in Adolescent Subjects  

PubMed Central

Emotions have been conceptualized as representations of bodily responses to a stimulus that critically involves the autonomic nervous system (ANS). An association between amygdala activation and ANS activity has been shown in adults. However, to date, no studies have demonstrated this association in adolescents. Examining the interaction between the ANS and amygdala in healthy adolescents may provide information about age-related changes in the association between amygdala activation and ANS measures. Therefore, the aim of this study was to examine the relationship between amygdala activation and heart rate in normal adolescents. Eighteen 12- to 17-year old adolescents participated. Heart rate data was collected during functional magnetic resonance imaging while subjects performed a facial expression matching task that reliably activates the amygdala. Adolescents showed significant amygdala activation for all facial expressions relative to the shape-matching, control task. Moreover, the degree of activation in the right amygdala for Fearful faces was significantly correlated with heart rate (Spearman’s rho = 0.55, p = 0.018, two-tailed). This study shows that amygdala activity is related to heart rate in healthy adolescents. Thus, similar to adults, adolescents show a coupling between processing emotional events and adjusting the ANS accordingly. Furthermore, this study confirms previous adolescent studies showing amygdala activation to Fearful, Angry, and Happy faces. Finally, the results of the present study lay the foundation for future research to investigate whether adolescents with mood or anxiety disorders show an altered coupling between processing emotionally salient events and ANS activity.

Yang, Tony T.; Simmons, Alan N.; Matthews, Scott C.; Tapert, Susan F.; Bischoff-Grethe, Amanda; Frank, Guido; Arce, Estibaliz; Paulus, Martin P.

2007-01-01

341

A comparison of heart rate during rest and work in shift workers with different work styles.  

PubMed

To determine if the type of work performed should be considered in research on shift work and cardiovascular disease, we compared the heart rates, total number of steps walked, and blood pressures of 12 shift workers on the same rotating 3-shift schedule in a pulp and paper mill. Six workers were selected from the paper manufacturing section (group 1) and six workers from the chemical products section (group 2). Average heart rate (in beats per min) monitored during duty time was 84.3 in group 1 and 87.4 in group 2. Average heart rate during work was not significantly higher than that during rest in both groups 1 (work 85.8, rest 75.3) and 2 (work 87.9, rest 83.1). There was no significant difference in the total number of steps walked. A non-significant decrease in systolic blood pressure value was found in group 1 compared with that in group 2. Although future studies will be needed to explain the relation between different work styles and their effects on the health of shift workers, our results suggest no significant difference in heart rates among workers engaged in different kinds of work on the same shift work schedule. PMID:14620672

Inoue, Masaiwa; Fujimura, Takae; Morita, Hideko; Inagaki, Junko; Kan, Hirohiko; Harada, Noriaki

2003-10-01

342

Estimation of Measurement Characteristics of Ultrasound Fetal Heart Rate Monitor  

NASA Astrophysics Data System (ADS)

Ultrasound fetal heart rate monitoring is very useful to determine the status of the fetus because it is noninvasive. In order to ensure the accuracy of the fetal heart rate (FHR) obtained from the ultrasound Doppler data, we measure the fetal electrocardiogram (ECG) directly and obtain the Doppler data simultaneously. The FHR differences of the Doppler data from the direct ECG data are concentrated at 0 bpm (beats per minute), and are practically symmetrical. The distribution is found to be very close to the Student's t distribution by the test of goodness of fit with the chi-square test. The spectral density of the FHR differences shows the white noise spectrum without any dominant peaks. Furthermore, the f-n (n>1) fluctuation is observed both with the ultrasound Doppler FHR and with the direct ECG FHR. Thus, it is confirmed that the FHR observation and observation of the f-n (n>1) fluctuation using the ultrasound Doppler FHR are as useful as the direct ECG.

Noguchi, Yasuaki; Mamune, Hideyuki; Sugimoto, Suguru; Yoshida, Atsushi; Sasa, Hidenori; Kobayashi, Hisaaki; Kobayashi, Mitsunao

1995-05-01

343

Fetal behavior and heart rate in twin pregnancy: a review.  

PubMed

Fetal movements and fetal heart rate (FHR) are well-established markers of fetal well-being and maturation of the fetal central nervous system. The purpose of this paper is to review and discuss the available knowledge on fetal movements and heart rate patterns in twin pregnancies. There is some evidence for an association or similarity in fetal movement incidences or FHR patterns between both members of twin pairs. However, the temporal occurrence of these patterns seems to be for the most part asynchronous, especially when stricter criteria are used to define synchrony. The available data suggest that fetal behavior is largely independent of sex combination, fetal position, and presentation. Conversely, chorionicity appears to have some influence on fetal behavior, mainly before 30 weeks of gestation. There is preliminary evidence for the continuity of inter-individual differences in fetal activity and FHR patterns over pregnancy. Comparisons between studies are limited by large methodological differences and absence of uniform concepts and definitions. Future studies with high methodological quality are needed to provide a more comprehensive knowledge of normal fetal behavior in twin pregnancy. PMID:23312077

Tendais, Iva; Visser, Gerard H A; Figueiredo, Bárbara; Montenegro, Nuno; Mulder, Eduard J H

2013-01-14

344

Relation of Anemia to Low Heart Rate Variability in Patients With Coronary Heart Disease (from the Heart and Soul Study)  

PubMed Central

We examined the association between anemia (hemoglobin ?12 g/dl) and 6 indexes of heart rate variability (HRV) as measured by 24-hour ambulatory electrocardiography in a cross-sectional study of 874 outpatients who had stable coronary heart disease. Of 90 participants who had anemia, 29% to 41% had low HRV, defined as the lowest quartile of each HRV index, compared with 23% to 25% of the 784 participants who did not have anemia (comparison p values <0.05 for all HRV indexes except high-frequency power). With the exception of high-frequency power, each 1 g/dl decrease in hemoglobin was associated with increased odds of having low HRV. This association remained strong after adjustment for potential confounding variables, including ischemia, left ventricular mass, left ventricular ejection fraction, and diastolic dysfunction. Thus, anemia is associated with low HRV in ambulatory patients who have stable coronary heart disease. Low HRV could potentially mediate the association of anemia with increased cardiac risk.

Gehi, Anil; Ix, Joachim; Shlipak, Michael; Pipkin, Sharon S.; Whooley, Mary A.

2009-01-01

345

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

PubMed

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. PMID:23553172

Dural, Muhammet; Kabakc?, Giray; C?nar, Ne?e; Erba?, Tomris; Canpolat, U?ur; Gürses, Kadri Murat; Tokgözo?lu, Lale; Oto, Ali; Kaya, Ergün Bar??; Yorgun, Hikmet; Sahiner, Levent; Da?delen, Selçuk; Aytemir, Kudret

2013-04-01

346

Scientific Comparison of Different Online Heart Rate Monitoring Systems  

PubMed Central

Recent technical development focused on real-time heart rate monitoring instead of postexercise evaluation of recorded data. There are several systems on the market that allow direct and real-time monitoring of several individuals at the same time. The present study compared the systems of Polar, Acentas, Activio, and Suunto in a field test with twelve subjects regarding failure quota, operating distance, and ECG validity. Moreover, the installation and use of software and hardware were evaluated with a quality rating system. Chest belts were evaluated with a questionnaire, too. Overall the system of Acentas reached the best mark of all systems, but detailed results showed that every system has its advantages and disadvantages depending on using purpose, location, and weather. So this evaluation cannot recommend a single system but rather shows strength and weakness of all systems and additionally can be used for further system improvements.

Schonfelder, Martin; Hinterseher, Georg; Peter, Philipp; Spitzenpfeil, Peter

2011-01-01

347

Contact-free heart rate measurement using multiple video data  

NASA Astrophysics Data System (ADS)

In this paper, we propose a contact-free heart rate measurement method by analyzing sequential images of multiple video data. In the proposed method, skin-like pixels are firstly detected from multiple video data for extracting the color features. These color features are synchronized and analyzed by independent component analysis. A representative component is finally selected among these independent component candidates to measure the HR, which achieves under 2% deviation on average compared with a pulse oximeter in the controllable environment. The advantages of the proposed method include: 1) it uses low cost and high accessibility camera device; 2) it eases users' discomfort by utilizing contact-free measurement; and 3) it achieves the low error rate and the high stability by integrating multiple video data.

Hung, Pang-Chan; Lee, Kual-Zheng; Tsai, Luo-Wei

2013-10-01

348

A Role for BK Channels in Heart Rate Regulation in Rodents  

PubMed Central

The heart generates and propagates action potentials through synchronized activation of ion channels allowing inward Na+ and Ca2+ and outward K+ currents. There are a number of K+ channel types expressed in the heart that play key roles in regulating the cardiac cycle. Large conductance calcium-activated potassium (BK) ion channels are not thought to be directly involved in heart function. Here we present evidence that heart rate can be significantly reduced by inhibiting the activity of BK channels. Agents that specifically inhibit BK channel activity, including paxilline and lolitrem B, slowed heart rate in conscious wild-type mice by 30% and 42%, respectively. Heart rate of BK channel knock-out mice (Kcnma1?/?) was not affected by these BK channel inhibitors, suggesting that the changes to heart rate were specifically mediated through BK channels. The possibility that these effects were mediated through BK channels peripheral to the heart was ruled out with experiments using isolated, perfused rat hearts, which showed a significant reduction in heart rate when treated with the BK channel inhibitors paxilline (1 µM), lolitrem B (1 µM), and iberiotoxin (0.23 µM), of 34%, 60%, and 42%, respectively. Furthermore, paxilline was shown to decrease heart rate in a dose-dependent manner. These results implicate BK channels located in the heart to be directly involved in the regulation of heart rate.

Imlach, Wendy L.; Finch, Sarah C.; Miller, John H.; Meredith, Andrea L.; Dalziel, Julie E.

2010-01-01

349

Oxygen Kinetics and Heart Rate Response during Early Recovery from Exercise in Patients with Heart Failure.  

PubMed

Background. The purpose of this study was to assess the post-exercise O(2) uptake and heart rate response in patients with heart failure (HF) in comparison to healthy individuals. Methods and Results. Exercise testing of all subjects was conducted according to the RITE-protocol. The study subjects were classified according to their peak oxygen uptake (peak VO(2)) in four groups: healthy individuals with a peak VO(2) >22?mL/kg/min (group 1, n: 50), and patients with HF and a peak VO(2) of 18-22?mL/kg/min, (group 2, n: 48), 14-18?mL/kg/min (group 3, n: 57), and <14?mL/kg/min (group 4, n: 31). Both peak VO(2) and HR declined more slowly in the patients with HF than in the normal subjects. Recovery of VO(2) and HR followed monoexponential kinetics in the early post-recovery phase. This enabled the determination of a time constant for both HR and VO(2) (TC VO(2) and TC HR). From group 1 to 4 there was a prolongation of the time constant for VO(2) and HR: TC VO(2) (group 1: 110 ± 34, group 2: 197 ± 43, group 3: 238 ± 80, and group 4: 278 ± 50?sec), and TC HR (group 1: 148 ± 82, group 2: 290 ± 65, group 3: 320 ± 58, and group 4: 376 ± 55?sec). Conclusion. The rate of decline of VO(2) and HR in the early post-exercise phase is inversely related to the peak VO(2). The time constant for oxygen uptake (TC VO(2)) and heart rate (TC HR) might prove a useful parameter for more precise monitoring and grading of HF. PMID:22312564

Kriatselis, Charalampos D; Nedios, Sotirios; Kelle, Sebastian; Helbig, Sebastian; Gottwik, Martin; von Bary, Christian

2012-01-24

350

Simultaneous measurement of instantaneous heart rate and chest wall plethysmography in short-term, metronome guided heart rate variability studies: suitability for assessment of autonomic dysfunction  

Microsoft Academic Search

Instantaneous heart rate and chest wall motion were measured using a 3-lead ECG and an air pressure chest wall plethysmography system. Chest wall plethysmography traces were found to accurately represent the breathing pattern as measured by spirometry (average correlation coefficient 0.944); though no attempt was made to calibrate plethysmography voltage output to tidal volume. Simultaneous measurements of heart rate and

S. Perring; E. Jones

2003-01-01

351

Vagally mediated heart rate variability and heart rate entropy as predictors of treatment outcome in flight phobia.  

PubMed

In the present study a computer-assisted exposure-based treatment was applied to 54 flight phobics and the predictive role of vagally mediated heart rate (HR) variability (high frequency, 0.15-0.4 Hz band power) and heart rate entropy (HR time series sample entropy) on treatment outcome was investigated. Both physiological measures were taken under controlled breathing at 0.2 Hz and during exposure to a fearful sequence of audiovisual stimuli. Hierarchical regression analyses were conducted to assess the predictive power of these variables in these conditions on treatment self-report measures at the end of treatment and at 6 months follow-up, as well as on the behavioral treatment outcome (i.e. flying at the end of treatment). Regression models predicting significant amounts of outcome variance could be built only when HR entropy was added to the HR variability measure in a second step of the regression analyses. HR variability alone was not found to be a good predictor of neither self-reported nor behavioral treatment outcomes. PMID:17765387

Bornas, Xavier; Llabrés, Jordi; Tortella-Feliu, Miquel; Fullana, Miquel A; Montoya, Pedro; López, Ana; Noguera, Miquel; Gelabert, Joan M

2007-07-28

352

Trends in age-adjusted coronary heart disease mortality rates in Slovakia between 1993 and 2009.  

PubMed

Cardiovascular diseases (CVD) and especially coronary heart disease (CHD) are the main causes of death in the Slovak Republic (SR). The aim of this study is to explore trends in age-adjusted coronary heart disease mortality rates in the whole Slovak population and in the population of working age between the years 1993 and 2009. A related indicator - potential years of life lost (PYLL) due to CHD--was calculated in the same period for males and females. Crude CHD mortality rates were age-adjusted using European standard population. The joinpoint Poisson regression was performed in order to find out the annual percentage change in trends. The age-adjusted CHD mortality rates decreased in the Slovak population and also in the population of working age. The change was significant only within the working-age sub-group. We found that partial diagnoses (myocardial infarction and chronic ischaemic heart disease) developed in the mirror-like manner. PYLL per 100,000 decreased during the observed period and the decline was more prominent in males. For further research we recommend to focus on several other issues, namely, to examine the validity of cause of death codes, to examine the development of mortality rates in selected age groups, to find out the cause of differential development of mortality rates in the Slovak Republic in comparison with the Czech Republic and Poland, and to explain the causes of decrease of the age-adjusted CHD mortality rates in younger age groups in Slovakia. PMID:24053062

Psota, Marek; Pekarciková, Jarmila; O'Mullane, Monica; Rusnák, Martin

2013-06-01

353

Several common variants modulate heart rate, PR interval and QRS duration  

Microsoft Academic Search

Electrocardiographic measures are indicative of the function of the cardiac conduction system. To search for sequence variants that modulate heart rate, PR interval and QRS duration in individuals of European descent, we performed a genome-wide association study in ?10,000 individuals and followed up the top signals in an additional ?10,000 individuals. We identified several genome-wide significant associations (with P <

Daniel F Gudbjartsson; David O Arnar; Gudmar Thorleifsson; Gudmundur Thorgeirsson; Hrafnhildur Stefansdottir; Sigurjon A Gudjonsson; Aslaug Jonasdottir; Ellisiv B Mathiesen; Inger Njølstad; Audhild Nyrnes; Tom Wilsgaard; Erin M Hald; Kristian Hveem; Camilla Stoltenberg; Maja-Lisa Løchen; Augustine Kong; Unnur Thorsteinsdottir; Hilma Holm; Kari Stefansson

2010-01-01

354

Circadian control of heart rate in young insulin-dependent diabetes mellitus patients  

Microsoft Academic Search

Our objective was to determine whether young insulin-dependent diabetes mellitus (IDDM) patients without complications have abnormal circadian patterns of sympathetic or parasympathetic control of heart rate. Twenty-four-hour electrocardiographic recordings in 26 IDDM patients without complications and 27 control subjects were obtained. Patients were in good health and participated in their usual daily activities. Power spectral analysis was performed to determine

Robert P. Hoffman; Michael G. Kienzle

1996-01-01

355

Orthostatic influence on heart rate and blood pressure variability in trained persons with tetraplegia  

Microsoft Academic Search

To examine the orthostatic influence on heart rate and blood pressure variability in persons with tetraplegia playing wheelchair\\u000a basketball, ten trained persons with tetraplegia, ten untrained persons with tetraplegia, and ten able-bodied participated\\u000a in this study. Spectrum analysis of the ECG R–R interval and blood-pressure on a beat-by-beat basis during head-up tilt 60°\\u000a sitting were performed. The ratio of the

Yasuko Otsuka; Norihiro Shima; Toshio Moritani; Kuniharu Okuda; Kyonosuke Yabe

2008-01-01

356

Effects of isokinetic, isotonic and isometric submaximal exercise on heart rate and blood pressure  

Microsoft Academic Search

The purpose of the present study was to compare arterial pressure (AP) and heart rate (HR) responses to submaximal isokinetic,\\u000a isotonic and isometric exercises currently employed in physical rehabilitation therapy in terms of both magnitude and time-course.\\u000a To this aim AP and HR were continuously and noninvasively measured in ten healthy subjects performing isokinetic, isotonic\\u000a and isometric exercises at the

Ferdinando Iellamo; Jacopo M. Legramante; Gianfranco Raimondi; Filippo Castrucci; Carlo Damiani; Calogero Foti; Giuseppe Peruzzi; Ignazio Caruso

1997-01-01

357

Blood pressure, heart rate and catecholamine response during riberoptic nasotracheal intubation under general anesthesia  

Microsoft Academic Search

Arterial blood pressure (ABP) and heart rate were recorded at one-minute intervals during several stages of intubation in\\u000a the fiberscope group and the laryngoscope group, to determine if fiberoptic nasotracheal intubation would result in fewer\\u000a hemodynamic and catecholamine responses than when intubation was performed with a Macintosh laryngoscope. Blood samples were\\u000a also taken to measure plasma catecholamine concentration immediately after

Takayuki Tsubaki; Kazuya Aono; Takahisa Nakajima; Akio Shigematsu

1992-01-01

358

Determinants of the variability of heart rate measures during a competitive period in young soccer players  

Microsoft Academic Search

Measurements of exercise heart rate (HRex), HR recovery (HRR) and HR variability (HRV) are used as indices of training status. However, the day-to-day variability\\u000a of these indices throughout a competitive soccer period is unknown. On 14 occasions during a 3-week competition camp, 18 under\\u000a 15 (U15) and 15 under 17 (U17) years soccer players performed a 5-min submaximal run, followed

Martin Buchheit; Alberto Mendez-Villanueva; Marc J. Quod; Nicholas Poulos; Pitre Bourdon

2010-01-01

359

Face immersion increases vagal activity as assessed by heart rate variability  

Microsoft Academic Search

We examined whether the diving reflex without breath-holding (face immersion alone) increases vagal activity, as determined\\u000a by heart rate variability. A group of 15 men [mean age 20 (SD 3) years, height 172 (SD 5)?cm, body mass 68 (SD 9)?kg] performed\\u000a 12 trials at various breathing frequencies (5, 10, 15, 20, 30 breaths?·?min?1 and uncontrolled breath) with or without face

Naoyuki Hayashi; Mutsuhisa Ishihara; Ayumu Tanaka; Tomonori Osumi; Takayoshi Yoshida

1997-01-01

360

Through-wall UWB radar operating within FCC's mask for sensing heart beat and breathing rate  

Microsoft Academic Search

Non-invasive sensing of heart beat and breathing rate using UWB radar within the FCC's mask between 3.1 to 10.6 GHz and operating within -41 dbm\\/MHz has been developed. Compared to existing radars, the EIRP of UWB is much lower and it can also achieve comparable performance with the unique capability of through the wall environment. The UWB radar transceiver system

M. Y. W. Chia; S. W. Leong; C. K. Sim; K. M. Chan

2005-01-01

361

Estimation and Modeling of QT-Interval Adaptation to Heart Rate Changes  

Microsoft Academic Search

This paper introduces a new method for QT-interval estimation. It consists in a batch processing mode of the improved Woody’s method. Performance of this methodology is evaluated using synthetic data. In parallel, a new model of QT-interval dynamics behavior related to heart rate changes is presented. Since two kinds of QT response have been pointed out, the main idea is

Aline Cabasson; Olivier Meste; Jean-Marc Vesin

2012-01-01

362

Utilizing Wearable Sensors to Investigate the Impact of Everyday Activities on Heart Rate  

Microsoft Academic Search

\\u000a Advances in sensor technologies have provided the opportunity to perform continuous and unobtrusive capturing of physiological\\u000a signals. One particular application that has benefitted from this technology is the remote monitoring and management of cardiovascular\\u000a conditions. In this paper, details of an investigation considering the impact of everyday activities on heart rate are presented.\\u000a ECG and accelerometer signals collected from wearable

Leo Galway; Shuai Zhang; Chris Nugent; Sally McClean; Dewar Finlay; Bryan Scotney

363

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

PubMed

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. PMID:22958623

Silvet, Helme; Hawkins, Lee Ann; Jacobson, Alan K

2012-09-09

364

Anxiety is not Manifested by Elevated Heart Rate and Blood Pressure in Acutely Ill Cardiac Patients.  

National Technical Information Service (NTIS)

Patients with acute myocardial infarction and heart failure are often anxious. Anxiety after acute myocardial infarction may cause in-hospital complications and increased mortality. Clinicians often use heart rate and blood pressure as indicators of anxie...

M. J. DeJong D. K. Moser K. An M. L. Chung

2004-01-01

365

Getting to the Heart of the Matter: Written Disclosure, Gender, and Heart Rate  

PubMed Central

Objective The present study examined gender differences in the psychologic and physical symptom changes associated with written disclosure. Methods Male (n = 48) and female (n = 46) college students were assigned to either a written disclosure condition or a control writing condition. Participants in each condition wrote on 3 consecutive days for 20 minutes each session. Heart rate was recorded during each writing session and the narratives were examined for linguistic content. Participants completed measures of psychologic and physical health at baseline and again 1 month later. Results Participants assigned to the written disclosure condition reported significantly greater psychological and physical health benefits at follow up compared with the control group participants. No significant gender differences were found among those participants assigned to the written disclosure condition. Additionally, although heart rate reactivity and changes in the use of words denoting positive emotion, negative emotion, and cognitive appraisal significantly differed between the writing conditions, no significant gender differences in these variables were found among individuals assigned to the written disclosure condition. Conclusions Written disclosure is associated with significant improvements in both psychologic and physical health for men and women. There was no support for the notion that men may derive greater benefits than women from written disclosure. Furthermore, the results of this study indicate that changes in physiological reactivity and word use associated with written disclosure do not differ between men and women.

Epstein, Eva M.; Sloan, Denise M.; Marx, Brian P.

2006-01-01

366

5 CFR 430.208 - Rating performance.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Rating performance. 430.208 Section 430.208 Administrative...PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT Performance Appraisal for General Schedule,...

2013-01-01

367

Heart Rate and Initial Presentation of Cardiovascular Diseases (Caliber)  

ClinicalTrials.gov

Abdominal Aortic Aneurysm; Coronary Heart Disease NOS; Unheralded Coronary Death; Intracerebral Haemorrhage; Heart Failure; Ischemic Stroke; Myocardial Infarction; Stroke; Peripheral Arterial Disease; Stable Angina Pectoris; Subarachnoid Haemorrhage; Transient Ischemic Attack; Unstable Angina; Cardiac Arrest, Sudden Cardiac Death

2013-09-17

368

The predictive value of resting heart rate following osmotherapy in brain injury: back to basics  

PubMed Central

Background The importance of resting heart rate as a prognostic factor was described in several studies. An elevated heart rate is an independent risk factor for adverse cardiovascular events and total mortality in patients with coronary artery disease, chronic heart failure, and the general population. Also heart rate is elevated in the Multi Organ Dysfunction Syndrome (MODS) and the mortality due to MODS is highly correlated with inadequate sinus tachycardia. To evaluate the value of resting heart rate in predicting mortality in patients with traumatic brain injury along scoring systems like Acute Physiology and Chronic Health Evaluation(APACHE II), Sequential Organ Failure Assessment (SOFA) and Glasgow Coma Score (GCS). Method By analyzing data which was collected from an open labeled randomized clinical trial that compared the different means of osmotherapy (mannitol vs bolus or infusion hypertonic saline), heart rate, GCS, APACHE II and SOFA score were measured at baseline and daily for 7 days up to 60 days and the relationship between elevated heart rate and mortality during the first 7 days and 60th day were assessed. Results After adjustments for confounding factors, although there was no difference in mean heart rate between either groups of alive and expired patients, however, we have found a relative correlation between 60th day mortality rate and resting heart rate (P=0.07). Conclusion Heart rate can be a prognostic factor for estimating mortality rate in brain injury patients along with APACHE II and SOFA scores in patients with brain injury.

2012-01-01

369

Major Depression with Ischemic Heart Disease: Effects of Paroxetine and Nortriptyline on Measures of Nonlinearity and Chaos of Heart Rate  

Microsoft Academic Search

Depression is associated with increased cardiovascular mortality in patients with preexisting cardiac illness. A decrease in cardiac vagal function as suggested by a decrease in heart rate variability (HRV) or heart period variability has been linked to sudden death in patients with cardiac disease as well as in normal controls. Recent studies have shown decreased vagal function in cardiac patients

Vikram K. Yeragani; Steven Roose; Mallika Mallavarapu; R. K. A. Radhakrishna; Vanessa Pesce

2002-01-01

370

Ventilatory response to exercise correlates with impaired heart rate variability in patients with chronic congestive heart failure  

Microsoft Academic Search

In chronic congestive heart failure (CHF) an overactivity of muscle ergoreceptors and peripheral chemoreceptors may lead to an increased ventilatory response to exercise and contribute to the autonomic imbalance. The analysis of heart rate variability (HRV), which is a reliable method of studying autonomic regulations within the cardiovascular system, showed depressed HRV indexes in CHF, but predictors of abnormal HRV

Piotr Ponikowski; Tuan Peng Chua; Massimo Piepoli; Waldemar Banasiak; Stefan D Anker; Roman Szelemej; Wlodzimierz Molenda; Krzysztof Wrabec; Alessandro Capucci; Andrew J. S Coats

1998-01-01

371

Effects of pinacidil, verapamil, and heart rate on afterdepolarizations in the guinea-pig heart in vivo  

Microsoft Academic Search

Summary Recently, ionic current simulation in the Luo-Rudy model has elucidated putative mechanisms of afterdepolarizations under various experimental conditions. The present study was aimed at gaining insight into the differential mechanism of different types of afterdepolarizations in the guinea-pig heart in vivo. The effects of pharmacological and heart rate perturbations on early (EADs) and delayed (DADs) afterdepolarizations, induced by either

Jiang Xu; Sina Zaim; Amir Pelleg

1996-01-01

372

Interaction between heart rate and calcium concentration in the control of contractile strength of the frog heart  

PubMed Central

1. The changes in twitch tension during the ascending and descending staircase of the frog heart have been examined under various experimental conditions including the hypodynamic and prehypodynamic state. 2. The descending staircase resembles the tension change after reduction of external calcium concentration in showing two consecutive phases, an initial rapid and later slow phase of tension decline. 3. The time course of the ascending staircase depends on the condition of the heart; it is slow after, and rapid before, development of the hypodynamic state. It is also rapid when elicited after conditioning periods of increased heart rate. 4. The tension transients in response to brief concentration steps of external calcium concentration were examined at various levels of heart rate. The results indicate that at high heart rates the sensitivity of heart cells to external calcium is increased. 5. The results are interpreted along the lines of a previous hypothesis relating tension development to the cooperative action of two intracellular calcium compounds. The additional assumption is made that an intermediary exists which facilitates calcium movements in heart cells to an extent depending on the level of heart rate.

Chapman, R. A.; Niedergerke, R.

1970-01-01

373

Pulse pressure and heart rate: independent risk factors for cancer?  

PubMed

In the present study, the roles of heart rate (HR) and pulse pressure (PP) on cancer mortality, after taking into account physical activity, cigarette smoking, alcohol consumption and other confounding factors or underlying disease, were examined in men. The study included 125,513 men aged 20 to 95 years who had a health check-up at the IPC Center between 1978 and 1988. HR and PP were classified into three groups: < 60, 60-80, > 80 bpm for HR and < 50, 51-64, > or = 65 mmHg for PP. Adjusted risk ratios related to the increment from one class of HR or PP to the next for all cancer mortality were 1.4 (1.2-1.5) and 1.3 (1.1-1.4), respectively. This relationship was independent of several known risk and confounding factors, especially cigarette smoking and physical activity, and could not be explained by the presence of underlying disease. PMID:11438415

Thomas, F; Guize, L; Bean, K; Benetos, A

2001-07-01

374

Robustness and perturbation in the modeled cascade heart rate variability  

NASA Astrophysics Data System (ADS)

In this study, numerical experiments are conducted to examine the robustness of using cascade to describe the multifractal heart rate variability (HRV) by perturbing the hierarchical time scale structure and the multiplicative rule of the cascade. It is shown that a rigid structure of the multiple time scales is not essential for the multifractal scaling in healthy HRV. So long as there exists a tree structure for the multiplication to take place, a multifractal HRV and related properties can be captured by using the cascade. But the perturbation of the multiplicative rule can lead to a qualitative change. In particular, a multifractal to monofractal HRV transition can result after the product law is perturbed to an additive one at the fast time scale. We suggest that this explains the similar HRV scaling transition in the parasympathetic nervous system blockade.

Lin, D. C.

2003-03-01

375

Correlated and uncorrelated heart rate fluctuations during relaxing visualization  

NASA Astrophysics Data System (ADS)

The heart rate variability (HRV) of healthy subjects practicing relaxing visualization is studied by use of three multiscale analysis techniques: the detrended fluctuation analysis (DFA), the entropy in natural time (ENT) and the average wavelet (AWC) coefficient. The scaling exponent of normal interbeat interval increments exhibits characteristics of the presence of long-range correlations. During relaxing visualization the HRV dynamics change in the sense that two new features emerge independent of each other: a respiration-induced periodicity that often dominates the HRV at short scales (<40 interbeat intervals) and the decrease of the scaling exponent at longer scales (40-512 interbeat intervals). In certain cases, the scaling exponent during relaxing visualization indicates the breakdown of long-range correlations. These characteristics have been previously seen in the HRV dynamics during non-REM sleep.

Papasimakis, N.; Pallikari, F.

2010-05-01

376

Heart rate variability in newborns with hypoxic brain injury.  

PubMed

In neonatal intensive care units, there is a need for continuous monitoring of sick newborns with perinatal hypoxic ischemic brain injury (HIE). We assessed the utility of heart rate variability (HRV) in newborns with acute HIE undergoing simultaneous continuous EEG (cEEG) and ECG monitoring. HIE was classified using clinical criteria as well as visual grading of cEEG. Newborns were divided into two groups depending on the severity of the hypoxic injury and outcome. Various HRV parameters were compared between these groups, and significantly decreased HRV was found in neonates with severe HIE. As HRV is affected by many factors, it is difficult to attribute this difference solely to HIE. However, this study suggests that further investigation of HRV as a monitoring tool for acute neonatal hypoxic injury is warranted. PMID:23852475

Mati?, Vladimir; Cherian, Perumpillichira J; Widjaja, Devy; Jansen, Katrien; Naulaers, Gunnar; Van Huffel, Sabine; De Vos, Maarten

2013-01-01

377

Running demands and heart rate response in rugby sevens referees.  

PubMed

The purpose of this study was to examine for the first time the match running demands and heart rate (HR) responses associated with elite rugby sevens referees. Twelve referees were analyzed over 38 games, using Global Positioning System. Referees covered an average distance of 1665.2 ± 203.5 m per game (15.1 ± 0.5 minutes). Over this distance, 22.3% (371.8 ± 48.9 m) was spent standing and walking, 25.9% (431.2 ± 92.6 m) jogging, 12.4% (206.5 ± 53.2 m) cruising, 23.8% (395.6 ± 94.3 m) striding, 8% (133.3 ± 61.6 m) high-intensity running, and 7.6% (126.7 ± 87.3 m) sprinting. The average maximal distance of sprints, the number of sprints, and the mean sprint distance over the game were 31.3 ± 13.4 m, 5.76 ± 3.6 sprints, and 19.9 ± 7.8 m, respectively. The referee's work-to-rest ratio was 3.5:1. There were no statistical differences between the first and second half in any of the running variables analyzed. The average HR in the second half (160 ± 9 b·min(-1); 86 ± 5% maximal heart rate (HRmax) of the estimated) was higher (p < 0.05) than the HR recorded in the first half (154 ± 11 b·min(-1); 83 ± 6% of the estimated HRmax). This study also suggests that the physical demands of referring in rugby sevens are quite different from those encountered in other rugby codes, and the training regimes need to meet the increased overall running demands and high-intensity running activity. PMID:22990568

Suarez-Arrones, Luis; Calvo-Lluch, África; Portillo, Javier; Sánchez, Francisco; Mendez-Villanueva, Alberto

2013-06-01

378

Heart Rate and Motion Analysis by GPS in Beach Soccer  

PubMed Central

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. Key points The distance covered per minute of play is around 100 m. Beach soccer is an intermittent sport with a work:rest ratio of 1.4:1. The playing surface in beach soccer is an important handicap to obtain maximum speeds. Beach soccer has a high physiological intensity, with more than half of the game is spent at intensities above 90 % of the HRmax.

Castellano, Julen; Casamichana, David

2010-01-01

379

Restlessness behaviour, heart rate and heart-rate variability of dairy cows milked in two types of automatic milking systems and auto-tandem milking parlours  

Microsoft Academic Search

In order to assess the welfare of cows milked in automatic milking systems (AMS), restlessness behaviour during milking (stepping, foot-lifting), heart rate (HR) and heart-rate variability (HRV) were investigated in cows milked in two different AMS models (AMS-1, AMS-2) and in auto-tandem milking parlours (ATM) on four commercial farms in each case.Stepping rates and proportions of milkings with foot-lifting were

Lorenz Gygax; Isabelle Neuffer; Christine Kaufmann; Rudolf Hauser; Beat Wechsler

2008-01-01

380

Effects of Moxa (Folium Artemisiae argyi) Smoke Exposure on Heart Rate and Heart Rate Variability in Healthy Young Adults: A Randomized, Controlled Human Study.  

PubMed

Objective. To determine the effects of the moxa smoke on human heart rate (HR) and heart rate variability (HRV). Methods. Fifty-five healthy young adults were randomly divided into experimental (n = 28) and control (n = 27) groups. Experimental subjects were exposed to moxa smoke (2.5 ± 0.5?mg/m(3)) twice for 25 minutes in one week. ECG monitoring was performed before, during, and after exposure. Control subjects were exposed to normal indoor air in a similar environment and similarly monitored. Followup was performed the following week. Short-term (5?min) HRV parameters were analyzed with HRV analysis software. SPSS software was used for statistical analysis. Results. During and after the first exposure, comparison of percentage changes or changes in all parameters between groups showed no significant differences. During the second exposure, percentage decrease in HR, percentage increases in lnTP, lnHF, lnLF, and RMSSD, and increase in PNN50 were significantly greater in the experimental group than in control. Conclusion. No significant adverse HRV effects were associated with this clinically routine 25-minute exposure to moxa smoke, and the data suggests that short-term exposure to moxa smoke might have positive regulating effects on human autonomic function. Further studies are warranted to confirm these findings. PMID:23762143

Cui, Yingxue; Zhao, Baixiao; Huang, Yuhai; Chen, Zhanghuang; Liu, Ping; Huang, Jian; Lao, Lixing

2013-05-23

381

The combined effect of the cold pressor test and isometric exercise on heart rate and blood pressure  

Microsoft Academic Search

Summary  The purpose of this study was to determine if the cold pressor test during isometric knee extension [15% of maximal voluntary contraction (MVC)] could have an additive effect on cardiovascular responses. Systolic and diastolic blood pressures, heart rate and pressure rate product were measured in eight healthy male subjects. The subjects performed the cold pressor tests and isometric leg extensions

D. Peikert; J. Smolander

1991-01-01

382

The heart rate method for estimating metabolic rate: review and recommendations.  

PubMed

Under most circumstances heart rate (f(H)) is correlated with the rate of oxygen consumption (VO(2)) and hence the rate of energy expenditure or metabolic rate (MR). For over 60 years this simple principle has underpinned the use of heart rate to estimate metabolic rate in a range of animal species and to answer questions about their physiology, behaviour and ecology. The heart rate method can be applied both quantitatively and qualitatively. The quantitative approach is a two-stage process where firstly f(H) and MR are measured simultaneously under controlled conditions and a predictive calibration relationship derived. Secondly, measurements of heart rate are made and converted to estimates of MR using the calibration relationship. The qualitative approach jumps directly to the second stage, comparing estimates of f(H) under different circumstances and drawing conclusions about MR under the assumption that a relationship exists. This review describes the range of studies which have adopted either the quantitative or qualitative approach to estimating the MR of birds, mammals and reptiles. Studies have tended to focus on species, states and questions which are hard to measure, control or define using other techniques. For example, species studied include large, wide-ranging species such as ungulates, marine predators, and domestic livestock while research questions have concerned behaviours such as flight, diving and the effects of stress. In particular, the qualitative approach has applied to circumstances and/or species where it may be hard or impossible to derive a calibration relationship for practical reasons. The calibration process itself can be complex and a number of factors such as body mass, activity state and stress levels can affect the relationship between f(H) and VO(2). I recommend that a quantitative approach be adopted wherever possible but that this may entail deriving a calibration relationship which is practical and applicable, rather than the most accurate possible. I conclude with a series of recommendations for the application and development of this method. PMID:20869457

Green, Jonathan A

2010-09-22

383

Effect of interscalene brachial plexus block on heart rate variability  

PubMed Central

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, Marina; Chantzi, Eleni; Bareka, Metaxia; Tsiaka, Katerina; Iatrou, Christos; Karachalios, Theophilos

2013-01-01

384

Pulse Modulated UHF Energy Illumination of the Heart Associated with Change in Heart Rate.  

National Technical Information Service (NTIS)

Recent reports indicate that illumination with UHF energy affects the heart and CNS. Isolated frog hearts were illuminated with pulse modulated UHF energy in this investigation. The pulses were synchronized with the ECG in an attempt to induce a positive ...

A. H. Frey E. Seifert

1968-01-01

385

Assessment of the effect of EMLA ® during venipuncture in the newborn by analysis of heart rate variability  

Microsoft Academic Search

The objective of this study was to investigate the effect of EMLA on the pain response when venipuncture was performed in 60 3-day-old healthy newborns. EMLA\\/placebo was applied to the back of the baby's hand, following a randomized, double-blind procedure. ECG and crying were recorded during the test. The incidence of crying, heart rate (HR) and spectral analysis of heart

Viveca Lindh; Urban Wiklund; Stellan Håkansson

2000-01-01

386

Performance measurement in congenital heart surgery: Benefits and drawbacks  

Microsoft Academic Search

Performance monitoring is playing an increasing role in modern congenital heart surgery. We present a number of examples to show the kinds of benefits that it can lead to. Conversely, we discuss some of the potential pitfalls including: errors in the collection of data; use of inappropriate data originally collected for a different purpose; assessment based on inadequate sample size;

Jaroslav F. Stark

2003-01-01

387

Heart rate variability during sympatho-excitatory challenges: Comparison between spontaneous and metronomic breathing  

Microsoft Academic Search

Respiration influences heart rate variability, leading to the suggestion that respiration should be controlled to assess autonomic\\u000a function by using heart rate variability. Clearly, control of respiration is advantageous or even essential in several experimental\\u000a circumstances. However, control of respiration, by itself, produces a small, but significant, increase in mean heart rate\\u000a and a decrease in respiratory synchronous variation in

Abhijit Patwardhan; Joyce Evans; Eugene Bruce; Charles Knapp

2001-01-01

388

Removal of Respiratory Influences From Heart Rate Variability in Stress Monitoring  

Microsoft Academic Search

This paper addresses a major weakness of traditional heart-rate-variability (HRV) analysis for the purpose of moni- toring stress: sensitivity to respiratory influences. To address this issue, a linear system-identification model of the cardiorespiratory system using commercial heart rate monitors and respiratory sensors was constructed. Subtraction of respiratory driven fluc- tuations in heart rate leads to a residual signal where the

Jongyoon Choi; Ricardo Gutierrez-Osuna

2011-01-01

389

Heart rate responses of women aged 23–67 years during competitive orienteering  

Microsoft Academic Search

Objectives: To compare the heart rate responses of women orienteers of different standards and to assess any relation between heart rate responses and age.Methods: Eighteen competitive women orienteers completed the study. They were divided into two groups: eight national standard orienteers (ages 23–67 years); 10 club standard orienteers (ages 24–67 years). Each participant had her heart rate monitored during a

S Bird; M George; J Balmer; R C R Davison

2003-01-01

390

Circadian rhythm changes in heart rate variability during chronic sound stress  

Microsoft Academic Search

To study the circadian rhythm changes of the heart rate variability (HRV) during chronic sound stress, Wistar rats were implanted\\u000a with telemetry transmitters and exposed to chronic ultrasound stress for 14 days. The heart rate, mean R-R intervals (mean\\u000a R-R) and body temperature were monitored hourly. The spectra of five-minute heart rate variability were plotted on a log-log\\u000a scale of

H. Takeuchi; A. Enzo; H. Minamitani

2001-01-01

391

Scaling graphs of heart rate time series in athletes demonstrate the VLF, LF and HF regions  

Microsoft Academic Search

Scaling analysis of heart rate time series has emerged as an useful tool for\\u000aassessment of autonomic cardiac control. We investigate the heart rate time\\u000aseries of ten athletes (five males and five females), by applying detrended\\u000afluctuation analysis (DFA). High resolution ECGs are recorded under\\u000astandardized resting conditions over 30 minutes and subsequently heart rate\\u000atime series are extracted

Mathias Baumert; Lars M Brechtel; Juergen Lock; Andreas Voss; Derek Abbott

2006-01-01

392

Diurnal variations in arousal: a naturalistic heart rate study in children with ADHD  

Microsoft Academic Search

Previous studies suggest an altered circadian regulation of arousal in children with attention-deficit hyperactivity disorder\\u000a (ADHD) as measured by activity, circadian preference, and sleep-wake patterns. Although heart rate is an important measure\\u000a to evaluate arousal profiles, to date it is unknown whether 24-h heart rate patterns differentiate between children with and\\u000a without ADHD. In this study, 24-h heart rate data

Lindita Imeraj; Inge Antrop; Herbert Roeyers; Ellen Deschepper; Sarah Bal; Dirk Deboutte

393

Amygdala Central Nucleus Lesions Attenuate Acoustic Startle Stimulus-Evoked Heart Rate Changes in Rats  

Microsoft Academic Search

Amygdala central nucleus (CNA) lesions were used to test the hypothesis that stimulus-evoked heart rate changes can reflect the development of fear during acoustic startle testing. A 120-dB white noise startle stimulus produced freezing as well as phasic heart rate accelerations and decelerations, and an abrupt decrease in tonic heart rate, in sham-operated rats. These responses were all significantly reduced

Brian J. Young; Robert N. Leaton

1996-01-01

394

Confronting a cardiovascular system model with heart rate and blood pressure data  

Microsoft Academic Search

The cardiovascular system may be investigated by observing fluctuations in the heart rate, blood pressure and rate of respiration. Its time evolution is governed by the baroreflex control mechanism, where the sympathetic and vagal nerves compete to increase and decrease the heart rate respectively. A nonlinear delay-differential equation model is constructed to describe this control mechanism and to explore the

P. E. McSharry; M. J. McGuinness; A. C. Fowler

2005-01-01

395

Chaotic Signatures of Heart Rate Variability and Its Power Spectrum in Health, Aging and Heart Failure  

PubMed Central

A paradox regarding the classic power spectral analysis of heart rate variability (HRV) is whether the characteristic high- (HF) and low-frequency (LF) spectral peaks represent stochastic or chaotic phenomena. Resolution of this fundamental issue is key to unraveling the mechanisms of HRV, which is critical to its proper use as a noninvasive marker for cardiac mortality risk assessment and stratification in congestive heart failure (CHF) and other cardiac dysfunctions. However, conventional techniques of nonlinear time series analysis generally lack sufficient sensitivity, specificity and robustness to discriminate chaos from random noise, much less quantify the chaos level. Here, we apply a ‘litmus test’ for heartbeat chaos based on a novel noise titration assay which affords a robust, specific, time-resolved and quantitative measure of the relative chaos level. Noise titration of running short-segment Holter tachograms from healthy subjects revealed circadian-dependent (or sleep/wake-dependent) heartbeat chaos that was linked to the HF component (respiratory sinus arrhythmia). The relative ‘HF chaos’ levels were similar in young and elderly subjects despite proportional age-related decreases in HF and LF power. In contrast, the near-regular heartbeat in CHF patients was primarily nonchaotic except punctuated by undetected ectopic beats and other abnormal beats, causing transient chaos. Such profound circadian-, age- and CHF-dependent changes in the chaotic and spectral characteristics of HRV were accompanied by little changes in approximate entropy, a measure of signal irregularity. The salient chaotic signatures of HRV in these subject groups reveal distinct autonomic, cardiac, respiratory and circadian/sleep-wake mechanisms that distinguish health and aging from CHF.

Wu, Guo-Qiang; Arzeno, Natalia M.; Shen, Lin-Lin; Tang, Da-Kan; Zheng, Da-An; Zhao, Nai-Qing; Eckberg, Dwain L.; Poon, Chi-Sang

2009-01-01

396

Abnormal baroreflex control of heart rate in decompensated congestive heart failure and reversal after compensation.  

PubMed

Congestive heart failure (CHF) causes impairment of baroreflex control of heart rate (HR). To determine if this derangement is reversible, the cardiac chronotropic control was assessed in 10 patients with class IV chronic CHF of various etiologies before and after compensation achieved by bed rest, salt restriction, diuretics and vasodilators. Mean time between the 2 studies was 15 +/- 3 days. The management was modified 3 days before the second autonomic evaluation, so as to reestablish the same diet and pharmacologic conditions of the previous study. Compensation led to significant reduction in symptom-based class, body weight, and pulmonary and systemic congestion. Mean +/- standard error of the mean HR responses (beats/min) before and after compensation were, respectively: (1) to atropine (0.04 mg/kg): 10 +/- 2 and 27 +/- 2 (p less than 0.01); (2) to handgrip (30% maximum capacity, 1 minute): 9 +/- 2 and 19 +/- 3 (p less than 0.005); (3) to headup tilt (5 minutes): 4 +/- 3 and 20 +/- 4 (p less than 0.005). Mean +/- standard error of the mean baroreflex sensitivity (ms/mm Hg) of RR responses to phenylephrine and amyl nitrate-induced changes in systolic pressure was, respectively, in each condition: phenylephrine, 0.9 +/- 0.2 and 8 +/- 2.3 (p less than 0.05); amyl nitrate, 0.3 +/- 0.2 and 4.1 +/- 1.1 (p less than 0.05). A significant correlation between improvement in HR responses to atropine and tilt and changes in body weight was obtained. These findings show a reversible component of impaired baroreflex control of HR in severe CHF, possibly due to its congestive effects. PMID:2000793

Marin-Neto, J A; Pintya, A O; Gallo Júnior, L; Maciel, B C

1991-03-15

397

Resting heart rate in patients with ischemic heart disease in Saudi Arabia and Egypt  

PubMed Central

Aim To assess the level of resting heart rate (RHR) in an outpatient population presenting with stable coronary artery disease (CAD) as well as to measure its association with current therapeutic management strategies for cardiovascular events. Materials and methods A multi-center cross-sectional survey was carried out in Saudi Arabia and Egypt over a three month period (between January 2007 and April 2007). 2049 patients with CAD without clinical heart failure (HF) were included in this study through “cluster sampling”. RHR was measured by manual palpitation. Results Mean age of CAD patients was 56.7 ± 10.4 and the mean RHR was 78.9 ± 13.9 b/m. 1686 patients (83.1%) were on ?-blockers for whom the RHR was 78.5 ± 14.0 b/m (95.5% had RHR ? 60 b/m, which is higher than recommended by the guidelines). 1094 (73.5%) of patients on ?-blockers were on a lower dose, probably to avoid the complications associated with such a class. Among those not on ?-blockers (16.9%), RHR was 80.9 ± 13.0 b/m. Moreover, 98 patients (4.8%) were on calcium channel blocker (diltiazem or verapamil) but not on ?-blockers, for whom the RHR was 80.9 ± 12.0 b/m. Finally, 163 patients (8.0%) were on both ?-blockers and the calcium channel blocker, and their RHR was 79.0 ± 14.4 b/m. Conclusion Optimal target RHR has not been achieved in a significant number of screened patients. Achievements of such targets are known to decrease mortality and to improve survival.

Kinsara, Abdulhalim J.; Najm, Hani K.; Anazi, Menwar Al; Tamim, Hani

2011-01-01

398

Changes in Heart Rate Variability in patients under local anesthesia.  

PubMed

Spectral analysis of Heart Rate Variability (HRV) is widely used for the assessment of cardiovascular autonomic control. Several studies have shown the effect of anesthetic agents on HRV parameters. In this study a systematic approach of HRV analysis has been employed. The effect caused by the ectopic beats on the spectral measurements has been investigated and results are presented. A detrending method using Wavelet Packets has been developed which was able to remove slow varying trend from HRV signals without causing significant changes in the low frequency (LF) and high frequency (HF) component of the HRV signal. Using this methodology electrocardiogram (ECG) signals from 14 patients undergoing local anesthesia (brachial plexus block) were analyzed with parametric Autoregressive (AR) method. The results showed that the LF/HF ratio values calculated from the HRV signal decreases within an hour of the application of the brachial plexus block compared to the values at the start of the procedure. This change was noticed in approximately 80% of the patients. PMID:18001949

Shafqat, K; Pal, S K; Kumari, S; Kyriacou, P A

2007-01-01

399

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

PubMed

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. PMID:22616190

Wang, Yudong; Li, Chuanyong

2012-04-01

400

Heart rate variability as a biomarker of fibromyalgia syndrome  

PubMed Central

Fibromyalgia (FM) is a chronic pain syndrome characterized by widespread mechanical tenderness, fatigue, nonrefreshing sleep and depressed mood. Several biological abnormalities have been described in FM patients, including elevated substance P in the cerebrospinal fluid, increased CNS sensitivity to painful and nonpainful stimuli and pervasive dysfunction of the autonomic nervous system (ANS). Such ANS abnormalities include, but are not limited to: tachycardia, postural intolerance, Raynaud’s phenomenon, and diarrhea or constipation. Heart rate variability (HRV) analysis of FM patients can be used to assess ANS dysfunction, specifically related to sympathovagal balance, which has provided evidence for nonabating sympathetic hyperactivity in this chronic pain population. Although not specific for FM, ANS dysfunction can be readily determined by HRV analysis requiring only computer analysis of electrocardiogram recordings by commercially available software. HRV has been shown to correlate with FM pain and is sensitive to change; in particular, pain related to physical and mental stressors. Thus, ANS dysfunction as assessed by HRV analysis may serve as a useful biomarker, and may become part of future FM diagnostic criteria and serve as a surrogate end point in clinical trials.

Staud, Roland

2009-01-01

401

Heart Rate Variability Analysis in Patients with Allergic Rhinitis  

PubMed Central

Background. Very few studies investigate the role of the autonomic nervous system in allergic rhinitis. In this study, we evaluated the autonomic nervous system in allergic rhinitis patients using heart rate variability (HRV) analysis. Methods. Eleven patients with allergic rhinitis and 13 healthy controls, aged between 19 and 40 years old, were enrolled in the study. Diagnosis of allergic rhinitis was based on clinical history, symptoms, and positive Phadiatop test. Electrocardiographic recordings on the sitting and supine positions were obtained for HRV analysis. Results. In the supine position, there were no significant statistical differences in very-low-frequency power (VLF, ?0.04?Hz), low-frequency power (LF, 0.04–0.15?Hz), high-frequency power (HF, 0.15–0.40?Hz), and the ratio of LF to HF (LF/HF) between the patient and control groups. The mean RR intervals significantly increased, while LF% and LF/HF significantly decreased in the patient group in the sitting position. Moreover, mean RR intervals, LF, and LF/HF, which were significantly different between the two positions in the control group, did not show a significant change with the posture change in the patient group. Conclusion. These suggest that patients with allergic rhinitis may have poor sympathetic modulation in the sitting position. Autonomic dysfunction may therefore play a role in the pathophysiology of allergic rhinitis.

Lee, Guo-She; Shiao, An-Suey; Ko, Jen-Hung; Shu, Chih-Hung

2013-01-01

402

Heart rate variability exhibits complication-dependent changes postsurgery.  

PubMed

"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. PMID:23091271

Scheffler, Patrick; Muccio, Salvatore; Egiziano, Giordano; Doonan, Robert J; Yu, Alice; Carli, Franco; Daskalopoulou, Stella S

2012-10-21

403

Heart-rate monitoring by air pressure and causal analysis  

NASA Astrophysics Data System (ADS)

Among lots of vital signals, heart-rate (HR) is an important index for diagnose human's health condition. For instance, HR provides an early stage of cardiac disease, autonomic nerve behavior, and so forth. However, currently, HR is measured only in medical checkups and clinical diagnosis during the rested state by using electrocardiograph (ECG). Thus, some serious cardiac events in daily life could be lost. Therefore, a continuous HR monitoring during 24 hours is desired. Considering the use in daily life, the monitoring should be noninvasive and low intrusive. Thus, in this paper, an HR monitoring in sleep by using air pressure sensors is proposed. The HR monitoring is realized by employing the causal analysis among air pressure and HR. The causality is described by employing fuzzy logic. According to the experiment on 7 males at age 22-25 (23 on average), the correlation coefficient against ECG is 0.73-0.97 (0.85 on average). In addition, the cause-effect structure for HR monitoring is arranged by employing causal decomposition, and the arranged causality is applied to HR monitoring in a setting posture. According to the additional experiment on 6 males, the correlation coefficient is 0.66-0.86 (0.76 on average). Therefore, the proposed method is suggested to have enough accuracy and robustness for some daily use cases.

Tsuchiya, Naoki; Nakajima, Hiroshi; Hata, Yutaka

2011-05-01

404

Heart Rate Recovery after Cognitive Challenge is Preserved with Age  

PubMed Central

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

405

Heart rate variability in children with cyanotic and acyanotic congenital heart disease: analysis by spectral and non linear indices.  

PubMed

Congenital heart defects affect the efficiency and functionality of the heart, and autonomic control of heart rate and of circulation can display a pathologic behavior in order to compensate for the hemodynamic alterations due to disease. While previous works have investigated heart rate variability (HRV) in specific pathologies, e.g. tetralogy of Fallot, the goal of this study was to assess HRV in children with a congenital heart malformation taking into account the effects of cyanotic and acyanotic defects, and comparing pathologic children with age matched controls. HRV, approximate entropy (ApEn) and sample entropy (SampEn) were calculated to discuss the dynamics and complexity of heart rhythms, and to evaluate the potential impairment of control mechanisms. Analyses showed that low frequency (LF) power and total power of HRV were significantly higher in children with a condition than in healthy controls, independently of cyanosis. Non linear indices were also significantly higher in pathologic subjects. Significant differences in LF, total power, ApEn and SampEn were found among cyanotic, acyanotic and healthy children. These results suggested that children with a congenital heart condition display more complex HRV and sympathetic overactivity, which may be aimed at compensating for hemodynamic alterations. Further studies should investigate whether corrective surgery and rehabilitation can improve HRV and restore its physiological features. PMID:23366851

Aletti, Federico; Ferrario, Manuela; de Jesus, Taiana Bertacini Almas; Stirbulov, Roberto; Silva, Audrey Borghi; Cerutti, Sergio; Sampaio, Luciana Malosa

2012-01-01

406

Higher Precision of Heart Rate Compared with VO2 to Predict Exercise Intensity in Endurance-Trained Runners.  

PubMed

The aim of the present study was to assess the precision of oxygen uptake with heart rate regression during track running in highly-trained runners. Twelve national and international level male long-distance road runners (age 30.7 ± 5.5 yrs, height 1.71 ± 0.04 m and mass 61.2 ± 5.8 kg) with a personal best on the half marathon of 62 min 37 s ± 1 min 22 s participated in the study. Each participant performed, in an all-weather synthetic track five, six min bouts at constant velocity with each bout at an increased running velocity. The starting velocity was 3.33 m·s(-1) with a 0.56 m·s(-1) increase on each subsequent bout. VO2 and heart rate were measured during the runs and blood lactate was assessed immediately after each run. Mean peak VO2 and mean peak heart rate were, respectively, 76.2 ± 9.7 mL·kg(-1)·min(-1) and 181 ± 13 beats·min(-1). The linearity of the regressions between heart rate, running velocity and VO2 were all very high (r > 0.99) with small standard errors of regression (i.e. Sy.x < 5% at the velocity associated with the 2 and 4 mmol·L(-1) lactate thresholds). The strong relationships between heart rate, running velocity and VO2 found in this study show that, in highly trained runners, it is possible to have heart rate as an accurate indicator of energy demand and of the running speed. Therefore, in this subject cohort it may be unnecessary to use VO2 to track changes in the subjects' running economy during training periods. Key pointsHeart rate is used in the control of exercise intensity in endurance sports.However, few studies have quantified the precision of its relationship with oxygen uptake in highly trained runners.We evaluated twelve elite half-marathon runners during track running at various intensities and established three regressions: oxygen uptake / heart rate; heart rate / running velocity and oxygen uptake / running velocity.The three regressions presented, respectively, imprecision of 4,2%, 2,75% and 4,5% at the velocity associated with the 4 mmol·L(-1) threshold.The results of the present study show that, in highly trained runners, it is possible to use heart rate as an accurate index of the external work rate during sub maximal running speeds. PMID:24149310

Reis, Victor M; den Tillaar, Roland Van; Marques, Mario C

2011-03-01

407

Heart rate after cardiac transplantation-lessons from the tortoise and the shrew.  

PubMed

There is a striking consistency in the total number of heart beats accrued over a lifetime across a range of animal species despite vast differences in size. Moreover, an inverse relationship is observed between heart rate and lifespan, leading to speculation that elevated heart rate could significantly affect longevity. It is the aim of this review to analyze heart rate as a contributing factor in defining the functional lifespan of the transplanted human heart, which may unavoidably determine the longevity of the recipient. Sinus tachycardia occurs as a result of sympathetic/parasympathetic denervation, an unavoidable consequence of transplantation. The effect of elevated heart rate in this cohort has been scarcely reported. We highlight herein multitudinous mechanisms whereby elevated heart rate accelerates the deterioration in cardiac function and arterial elasticity due to injury and stress accumulation. Additionally, we propose a significant role for heart rate in confounding the alloimmune response. Tachycardia exacerbates injurious episodes of myocardial ischemia and significantly increases the production of reactive oxygen species via increased metabolism. These factors promote immune infiltration and activation, contributing to acute and chronic rejection. Further research is required to assess the potential therapeutic benefits of heart rate reduction. PMID:23104250

Critchley, William R; Yonan, Nizar; Shaw, Steven M; Fildes, James E

2013-01-27

408

Impact of cyanotic heart disease on school performance.  

PubMed Central

Surgical correction greatly decreases the mortality and cardiac morbidity of cyanotic congenital heart disease, but children remain at risk of long term difficulties in other areas. A historical cohort study was conducted to determine the relation between heart disease and school performance in 29 children aged 7 to 12 years old with simple transposition of the great arteries or tetralogy of Fallot. All children had surgical correction of their lesion before 2.5 years of age. Those at greater risk of school difficulties because of recognised complications of their heart disease or for reasons other than directly attributable to the heart disease were excluded. Comparison was made with 36 children who had presented with cardiac murmurs at a similar age, but who did not require treatment. Children with cyanotic disease showed significantly poorer performance in all academic areas assessed by the Wide Range Achievement Test-Revised; the difference in group mean score (adjusted for differences in maternal education, sex, and parental occupational prestige) for reading was 10.3 points (confidence interval (CI) 1.25 to 19.34), for spelling 7.8 (CI 1.11 to 14.52), and for arithmetic 6.8 (CI 0.19 to 13.39). The differences in adjusted group means for the Wechsler Intelligence Scale for Children-Revised full scale, performance and verbal IQs were significant, particularly the later at 10.1 points (CI 2.59 to 17.61). Teacher reports indicated significant differences in arithmetic when outcome was dichotomised to 'below grade' or 'not below grade'. There were no significant associations between outcome measures and the medical or perioperative parameters, however, including those related to hypoxia. It is concluded that the increased incidence of academic problems and the nature of the cognitive difficulties in children with uncomplicated corrective cardiac surgery for cyanotic heart disease are not fully explained by chronic hypoxia, or by other factors related to the cardiac surgery.

Wright, M; Nolan, T

1994-01-01

409

Short communication Vagal heart rate responses to chronic beta-blockade in human heart failure relate to cardiac norepinephrine spillover  

Microsoft Academic Search

We have documented a pre-junctional h-2 adrenoceptor mediated reduction in cardiac norepinephrine spillover (CNES) in heart failure patients receiving chronic h-blockade. Our present objective was to ascertain the consequence of this decrease for vagal heart rate (HR) regulation by determining CNES, arterial baroreflex sensitivity for HR (BRS) and arterial baroreflex modulation of muscle sympathetic nerve activity (MSNA) before and upon

Toshihiko Kubo; John D. Parker; Eduardo R. Azevedo; Deborah J. Atchison; Gary E. Newton; Peter Picton; John S. Floras

410

Effects of Particulate Air Pollution on Blood Pressure and Heart Rate in Subjects with Cardiovascular Disease: A Multicenter Approach  

Microsoft Academic Search

Given the hypothesis that air pollution is associated with elevated blood pressure and heart rate, the effect of daily concentrations of air pollution on blood pressure and heart rate was assessed in 131 adults with coronary heart disease in Helsinki, Finland; Erfurt, Germany; and Amsterdam, the Netherlands. Blood pressure was measured by a digital monitor, and heart rate was calculated

Angela Ibald-Mulli; Kirsi L. Timonen; Annette Peters; Joachim Heinrich; Gabriele Wölke; Timo Lanki; Gintautas Buzorius; Wolfgang G. Kreyling; Jeroen de Hartog; Gerard Hoek; Harry M. ten Brink; Juha Pekkanen

2003-01-01

411

The effect of lithium chloride administration on brain and heart norepinephrine turnover rates  

Microsoft Academic Search

Summary The effect of Li+ on NE turnover rates in rat heart and brain was studied. Turnover rates were determined in brain and heart by blocking tyrosine hydroxylase with L-?-methyltyrosine and following the decline of NE with time or in heart by injecting3H-NE and following the decline of NE specific activity with time. Subacute treatment with LiCl in doses that

D. N. Stern; R. R. Fieve; N. H. Neff; E. Costa

1969-01-01

412

The role of heart rate in the development of cardiovascular disease  

Microsoft Academic Search

Heart rate is an independent risk factor for patients with cardiovascular disease, in particular with arterial hypertension,\\u000a myocardial infarction, coronary artery disease and heart failure. This relation is supported by a large number of animal studies\\u000a as well as clinical trials which are summarized in this article. These studies demonstrated detrimental effects of increased\\u000a heart rate on the function and

J.-C. Reil; M. Böhm

2007-01-01

413

Changes in extracellular muscle volume affect heart rate and blood pressure responses to static exercise  

NASA Astrophysics Data System (ADS)

To investigate the effect of ?g-induced peripheral extracellular fluid reductions on heart rate and blood pressure during isometric exercise, six healthy male subjects performed three calf ergometer test with different extracellular volumes of working muscles. In all tests, body positions during exercise were identical (supine with the knee joint flexed to 900). After a pre-exercise period of 25 min, during which calf volumes were manipulated, subjects had to counteract an external force of 180 N for 5 min. During the pre-exercise period three different protocols were applied. Test A: Subjects rested in the exercise position; test B: Body position was the same as in A but calf volume was increased by venous congestion (cuffs inflated to 80 mm Hg); test C: Calf volumes were decreased by a negative hydrostatic pressure (calves about 40 cm above heart level with the subjects supine). To clamp the changed calf volumes in tests B and C, cuffs were inflated to 300 mm Hg 5 min before the onset of exercise. This occlusion was maintained until termination of exercise. Compared to tests A and B, the reduced volume of test C led to significant increases in heart rate and blood pressure during exercise. Oxygen uptake did not exceed resting levels in B and C until cuffs were deflated, indicating that exclusively calf muscles contributed to the neurogenic peripheral drive. It is concluded that changes in extracellular muscle volume have to be taken into account when comparing heart rate and blood pressure during lg- and ?g- exercise.

Baum, K.; Essfeld, D.; Stegemann, J.

414

Electroencephalogram and Heart Rate Regulation to Familiar and Unfamiliar People in Children with Autism Spectrum Disorders  

ERIC Educational Resources Information Center

|Few studies have examined whether familiarity of partner affects social responses in children with autism. This study investigated heart rate regulation (respiratory sinus arrhythmia [RSA]: The myelinated vagus nerve's regulation of heart rate) and temporal-parietal electroencephalogram (EEG) activity while nineteen 8- to 12-year-old children…

Van Hecke, Amy Vaughan; Lebow, Jocelyn; Bal, Elgiz; Lamb, Damon; Harden, Emily; Kramer, Alexis; Denver, John; Bazhenova, Olga; Porges, Stephen W.

2009-01-01

415

Variations of Heart Rate During Sleep as a Function of the Sleep Cycle.  

National Technical Information Service (NTIS)

The paper describes heart rate characteristics during sleep paying particular attention to the sleep cycle. Averages and variances of heart rate are presented on ten subjects during two entire nights of sleep using approximately 3200 epochs of R-R interva...

A. J. Welch J. L. Aldredge

1973-01-01

416

Effects of shift work on QTc interval and blood pressure in relation to heart rate variability  

Microsoft Academic Search

Objectives: There is evidence that shift work contributes to excess cardiovascular mortality. The purpose of this study was to determine the effects of shift work on heart rate-corrected QT (QTc) and blood pressure in relation to heart rate variability (CVRR). Methods: The study population consisted of 153 male shiftworkers and 87 male day workers who were employed at a copper-smelting

Katsuyuki Murata; Eiji Yano; Hideki Hashimoto; Kanae Karita; Miwako Dakeishi

2005-01-01

417

Heart rate turbulence and left ventricular ejection fraction in Chagas disease  

Microsoft Academic Search

Aims Chagas disease patients often present premature ventricular complexes (PVCs), depression of left ventricular ejection fraction (LVEF) and autonomic dysfunction, which is generally evaluated by heart rate variability (HRV) analysis. As frequent PVCs may complicate HRV computation, we measured heart rate turbulence (HRT) and evaluated the correlation between ejection fraction and HRT or HRV in Chagas disease. Methods We studied

Fabrizio Tundo; Federico Lombardi; Manoel C. Rocha; Fernando Botoni; Georg Schmidt; Vladimir C. Barros; Braulio Muzzi; Murilo Gomes; Airandes Pinto; Antonio L. Ribeiro

2005-01-01

418

Incidence and hospital death rates associated with heart failure: A community-wide perspective  

Microsoft Academic Search

PurposeDespite often stated references to the emerging epidemic of heart failure in the United States, relatively little data are available describing the incidence and short-term death rates associated with this clinical syndrome. The objectives of this study were to describe the hospital incidence and death rates associated with acute heart failure and factors associated with an adverse hospital prognosis in

Robert J. Goldberg; Frederick A. Spencer; Cheryl Farmer; Theo E. Meyer; Stephen Pezzella

2005-01-01

419

Cardiovascular Fitness and Maximal Heart Rate Differences Among Three Ethnic Groups.  

ERIC Educational Resources Information Center

Examination of differences in maximal heart rate and treadmill time among three ethnic groups revealed no significant age-adjusted differences among white, black, and Mexican-American males, and suggested that black females' lower maximal heart rate may be explained by their lower cardiovascular fitness level when compared to those of other…

Farrell, S. W.

1988-01-01

420

Using Heart Rate Monitors in Research on Fitness Levels of Children in Physical Education.  

ERIC Educational Resources Information Center

Demonstrates the use of heart rate monitors (HRMs) in fitness research and examines heart rate intensity levels of middle school students while they participated in a variety of physical education activities throughout a school year. Research shows the HRM has considerable potential in assessing fitness achievements in school-age children. (GLR)

Strand, Brad; Reeder, Steve

1993-01-01

421

A model for the genesis of arterial pressure Mayer waves from heart rate and sympathetic activity  

Microsoft Academic Search

Both theoretic models and cross-spectral analyses suggest that an oscillating sympathetic nervous outflow generates the low-frequency arterial pressure fluctuations termed Mayer waves. Fluctuations in heart rate also have been suggested to relate closely to Mayer waves, but empiric models have not assessed the joint causative influences of heart rate and sympathetic activity. Therefore, we constructed a model based simply upon

Christopher W Myers; Michael A Cohen; Dwain L Eckberg; J. Andrew Taylor

2001-01-01

422

Interaction between age and aerobic fitness in determining heart rate dynamics  

Microsoft Academic Search

Heart rate variability (HRV) and phase-rectified signal averaging (PRSA) estimates of heart rate dynamics are diminished in older people compared with younger people. However, it is not fully elucidated whether these differences are related to age per se or to the concomitant influence of aerobic fitness. Aerobic fitness (peak oxygen uptake, gas exchange threshold, oxygen uptake kinetics, exercise economy) was

M A McNarry; M J Lewis

2012-01-01

423

A model of heart rate changes to detect seizures in severe epilepsy  

Microsoft Academic Search

Summary Aim of the study: An explorative study to assess the value of a model for the automatic detection and characterization of heart rate (HR) changes during seizures in severe epilepsy. Methods: Heart rate changes were monitored in 10 patients with 104 seizures, mostly tonic and myoclonic, to assess the value of various modalities for the detection of seizures based

Wouter J. C. van Elmpt; Tamara M. E. Nijsen; Paul A. M. Griep; Johan B. A. M. Arends

2006-01-01

424

Heart rate variability effect on the myocyte action potential duration restitution: Insights from switched systems theory  

Microsoft Academic Search

The physiological heart rate presents a stochastic behavior known as heart rate variability (HRV). In this framework the influence of HRV on the action potential duration (APD) of the atrial myocyte is analyzed in a computer model. We have found that introducing HRV into the myocyte action potential model decreases the APD of the extra beat S2 in an S1-S2

Hila Dvir; Sharon Zlochiver

2011-01-01

425

Clutch Effects Explain Heart Rate Variation in Embryonic Frogs (Cave Coqui, Eleutherodactylus cooki )  

Microsoft Academic Search

Few physiological studies to date have focused on whether var- iation among sibling groups during development can account for often large, intraspecific physiological variation. In this study, we measured heart rate in the direct-developing frog Eleutherodactylus cooki throughout its embryonic development and examined heart rate variation among egg clutches com- prising from 10 to 40 eggs. Clutches were collected in

W. Burggren; D. Crossley III; G. Rogowitz; D. Thompson

2003-01-01

426

Heart Rates of Elementary Physical Education Students during the Dancing Classrooms Program  

ERIC Educational Resources Information Center

|We examined how different types of dance activities, along with their duration, influenced heart rate responses among fifth-grade physical education students (N = 96) who participated in the Dancing Classrooms program. Results indicated that the overall Dancing Classrooms program elicits a moderate cardiovascular heart rate response (M = 124.4…

Nelson, Larry; Evans, Melissa; Guess, Wendy; Morris, Mary; Olson, Terry; Buckwalter, John

2011-01-01

427

Heart Rate Responses of Coach and Referee to Selected Events During a College Basketball Game.  

National Technical Information Service (NTIS)

Heart rate responses of a coach and a referee were continuously monitored by radio telemetry during a college basketball game. Analysis of data indicated that the heart rate of the coach was higher than that of the official for most of the contest. Events...

A. E. Coleman

1972-01-01

428

The relationships between exercise intensity, heart rate, and blood pressure during an incremental isometric exercise test  

Microsoft Academic Search

Currently, it is not possible to prescribe isometric exercise at an intensity that corresponds to given heart rates or systolic blood pressures. This might be useful in optimizing the effects of isometric exercise training. Therefore, the aim of this study was to explore the relationships between isometric exercise intensity and both heart rate and systolic blood pressure during repeated incremental

Jonathan D. Wiles; Simon R. Allum; Damian A. Coleman; Ian L. Swaine

2008-01-01

429

Relationship study of heart rate and systolic blood pressure for healthy peoples  

Microsoft Academic Search

Manual blood pressure measurement is not practical if it is taken frequently. Therefore, in this paper, an automatic measurement system that can measure systolic blood pressure (SBP) incessantly based on its relationship with a heart rate is introduced. The system examines the heart rate based on the electrocardiography (ECG) and its relationship with SBP from the healthy subjects. The data

N. H. Mahmood; N. A. Zakaria; S. N. Jalaludin; N. B. Sharifmuddin

2010-01-01

430

Blood Pressure and Heart Rate Responses to Anticipated High-stress Dental Treatment  

Microsoft Academic Search

Twenty-four healthy adults participated in a study to determine the effects of anticipated high-stress dental treatment on blood pressure and heart rate. Blood pressure, heart rate, and state anxiety were assessed prior to four consecutive dental appointments. Appointments 1, 2, and 4 were of relatively low stress and appointment 3 was of relatively high stress. Blood pressure was unaffected while

Frank M. Beck; Joël M. Weaver

1981-01-01

431

Risk factors for alcohol misuse: Examining heart rate reactivity to alcohol, alcohol sensitivity, and personality constructs  

Microsoft Academic Search

ObjectiveHeart rate reactivity to alcohol has been conceptualized as an index of alcohol-induced reward and has been associated with a sensation seeking personality profile. The goal of this study is to expand on previous findings regarding the significance of heart rate reactivity to alcohol while examining convergent lines of research on alcohol sensitivity, the rewarding effects of alcohol, and personality

Lara A. Ray; John McGeary; Erin Marshall; Kent E. Hutchison

2006-01-01

432

Cardiovascular Endurance and Heart Rate Variability in Adolescents With Type 1 or Type 2 Diabetes  

Microsoft Academic Search

Background. Incidence rates of both type 1 and type 2 diabetes mellitus (DM) are increasing in youth and may eventually contribute to premature heart disease in early adulthood. This investigation explored the influence of type of diabetes, gender, body mass index (BMI), metabolic control (HbA1c), exercise beliefs and physical activity on cardiovascular endurance (CE), and heart rate variability (HRV). Differences

Melissa Spezia Faulkner; Laurie Quinn; James H. Rimmer; Barry H. Rich

2005-01-01

433

Genetic correlation of exercise with heart rate and respiratory sinus arrhythmia  

Microsoft Academic Search

DE GEUS, E. J. C., D. I. BOOMSMA, and H. SNIEDER. Genetic Correlation of Exercise with Heart Rate and Respiratory Sinus Arrhythmia. Med. Sci. Sports Exerc., Vol. 35, No. 8, pp. 1287-1295, 2003. Purpose: A twin design was used to test whether the association between exercise behavior and heart rate and the association between exercise behavior and respiratory sinus arrhythmia

Geus de E. J. C; DORRET I. BOOMSMA; HAROLD SNIEDER

2003-01-01

434

The Influence of Motor Impairment on Autonomic Heart Rate Modulation among Children with Cerebral Palsy  

ERIC Educational Resources Information Center

|The study of heart rate variability is an important tool for a noninvasive evaluation of the neurocardiac integrity. The present study aims to evaluate the autonomic heart rate modulation in supine and standing positions in 12 children diagnosed with cerebral palsy and 16 children with typical motor development (control group), as well as to…

Zamuner, Antonio Roberto; Cunha, Andrea Baraldi; da Silva, Ester; Negri, Ana Paola; Tudella, Eloisa; Moreno, Marlene Aparecida

2011-01-01

435

Heart Rate-Specific Reference Ranges for Qt-Interval in Beagle Dogs  

Microsoft Academic Search

In toxicity studies, the ECG is recorded over a range of escalating doses and the assessment of QT prolongation is made by comparing treated to untreated animals. As the QT interval and heart rate are inversely related, any imbalance in the distribution of heart rate across groups may bias this comparison. To avoid that risk, a formula for correcting QT

Francois Vandenhende

2001-01-01

436

Circadian rhythms of heart rate in freely moving and restrained American lobsters, Homarus americanus  

Microsoft Academic Search

While circadian rhythms of locomotion have been reported in the American lobster, Homarus americanus, it is unclear whether heart rate is also modulated on a circadian basis. To address this issue, both heart rate and locomotor activity were continuously monitored in light-dark (LD) cycles and constant darkness (DD). Lobsters in running wheels exhibited significant nocturnal increases in locomotor activity and

Christopher C. Chabot; Laura K. Webb

2008-01-01

437

SKIPPING BREAKFAST: GENDER EFFECTS ON RESTING HEART RATE MEASURES IN PREADOLESCENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The cardiovascular response in children to morning nutrition has received little attention, and associated gender-related effects are virtually uninvestigated. This study evaluated resting heart-rate (HR) and heart-rate variability (HRV) in preadolescents after overnight fasting and again after eati...

438

Marihuana: Standardized Smoke Administration and Dose Effect Curves on Heart Rate in Humans  

Microsoft Academic Search

A spirometer was used to deliver marihuana and placebo smoke to human subjects. This procedure produced linear dose-effect curves on heart rate and replicable dose effects in individual subjects. No differences were observed between experienced and inexperienced smokers in responsiveness to heart rate increases produced by marihuana.

Pierre F. Renault; Charles R. Schuster; Richard Heinrich; Daniel X. Freeman

1971-01-01

439

The association of fetal heart rate patterns with nucleated red blood cell counts at birth  

Microsoft Academic Search

Objective: The purpose of this study was to evaluate the relationship between fetal heart rate patterns and fetal nucleated red blood cell counts. Study Design: Data were collected prospectively from March through September 2000. Umbilical cord blood was used for nucleated red blood cell analysis. The fetal heart rate pattern was analyzed for reactivity; presence, duration, and type of decelerations;

Asaf Ferber; Armando Grassi; Didem Akyol; Christopher O'Reilly-Green; Michael Y. Divon

2003-01-01

440

MINIMAL AND MAXIMAL SENSORY INTAKE AND EXERCISE AS UNCONDITIONED STIMULI IN HUMAN HEART-RATE CONDITIONING  

Microsoft Academic Search

THE ANTICIPATORY HUMAN HEART-RATE RESPONSES RESULTING FROM THE USE OF 3 CLASSES OF UCSS WERE EVALUATED IN 3 EXPERIMENTS. SS WERE 62 MALE UNDERGRADUATES. STIMULUS CLASSES WERE DERIVED FROM A PROPOSAL THAT HIGH STIMULUS INTAKE RESULTS IN A DECELERATORY HEART-RATE UCR, THAT REJECTION OF ENVIRONMENTAL INTAKE RESULTS IN AN ACCELERATORY CARDIAC UCR, AND THAT PHYSICAL EXERCISE RESULTS IN CARDIAC ACCELERATION.

DONALD M. WOOD; PAUL A. OBRIST

1968-01-01

441

Study of Algorithm for Heart Rate Detection Based on Bipolar Motion ECG  

Microsoft Academic Search

Heart rate is a very important indicator for both amount of exercise and motor function. A waistband-like bipolar ECG collect system was designed and used. Traditional method was ineffective to get correct heart rate value from the bipolar ECG signals collected under motion state. Two popular time-frequency analysis methods were used and compared. The result showed that Discrete Wavelet Transform

Lei Sheng; Chen Wei; Guo Lihua; Chen Yuquan

2011-01-01

442

Fear Potentiation of Acoustic Startle Stimulus-Evoked Heart Rate Changes in Rats  

Microsoft Academic Search

The present study examined the extent to which heart rate changes evoked by acoustic startle stimuli are affected by the development of fear during startle testing. The phasic heart rate responses of rats elicited by a 120-dB startle stimulus were characterized by decelerations that habituated across trials and accelerations that developed across trials in a manner that paralleled the development

Brian J. Young; Robert N. Leaton

1994-01-01

443

Using Heart Rate Monitors in Research on Fitness Levels of Children in Physical Education.  

ERIC Educational Resources Information Center

|Demonstrates the use of heart rate monitors (HRMs) in fitness research and examines heart rate intensity levels of middle school students while they participated in a variety of physical education activities throughout a school year. Research shows the HRM has considerable potential in assessing fitness achievements in school-age children. (GLR)|

Strand, Brad; Reeder, Steve

1993-01-01

444

Exercise Heart Rate as a Predictor of Oxygen Consumption During Decompression from Saturation Diving.  

National Technical Information Service (NTIS)

The correlation between heart rate and oxygen consumption has been questioned during submerged exercise or exercise under pressure. We studied the relationships of heart rate to oxygen consumption (VO2) and of VO2 to ergometer setting in eight divers duri...

B. E. Shykoff M. E. Knafelc

2002-01-01

445

Adaptive Mean and Trend Removal of Heart Rate Variability Using Kalman Filtering.  

National Technical Information Service (NTIS)

Analysis of heart rate van ability requires the calculation of the mean heart rate, Adaptive methods are important for online and real-time parameter estimation, In this paper we demonstrate the use of Kalman filtering to estimate adaptively the mean hear...

A. Schloegl J. Fortin W. Habenbacher M. Akay

2001-01-01

446

Evaluation of activity level of daily life based on heart rate and acceleration  

Microsoft Academic Search

A method for evaluating activity levels in daily life based on the heart rate and body acceleration is proposed. The method evaluates the amount of activity, excluding the effect of stress, by comparing between body acceleration and the intensity of exercise calculate from heart rate. A prototyping system that measures and displays the intensity of exercise and body acceleration at

Syunji Yazaki; Toshio Matsunaga

2010-01-01

447

Relations between the development of patterns of sleeping heart rate and body temperature in infants  

Microsoft Academic Search

Overnight patterns of rectal temperature and heart rate were recorded from 119 normal infants at weekly intervals from 7 to about 16 weeks of age. All data were collected in the infants' own homes. As previously reported, different infants developed an adult-like night time rectal temperature pattern abruptly at different ages. When heart rate data were collated by age, there

S A Petersen; C Pratt; M P Wailoo

2001-01-01

448

Heart rate variation for iodinated contrast medium injection based on adaptive template matching algorithm  

Microsoft Academic Search

CT scan provide valuable medical image information and intravenous iodinated contrast medium injection can enhance the image contrast quality. Some patients, who may suffer palpitation, emesis, and other stress phenomena, even induce death after intravenous iodinated contrast medium injection. In this paper, we develop a real-time risk indicator based on patients' heart rate variation. The heart rate was extracted from

Kang-Ming Chang; You-Cyuan Su; Shing-Hong Liu; Shi-Chung Yang; Yu-Ling Li

2006-01-01

449

Sensitivity and reproducibility of accelerometry and heart rate in physical strain assessment during prosthetic gait  

Microsoft Academic Search

Accelerometry and heart rate (HR) are frequently used indicators of physical strain during normal daily life. The present study focused on the sensitivity and reproducibility of accelerometry (body motility, the intensity of body movement measured with accelerometry) and HR (percentage maximal heart rate reserve, %HRR max) in the assessment of physical strain during walking in persons with a lower leg

Johannes B. J. Bussmann; Hendrika J. G. van den Berg-Emons; Sonia M. Angulo; Theo Stijnen; Henk J. Stam

2004-01-01

450

Digestive state influences the heart rate hysteresis and rates of heat exchange in the varanid lizard Varanus rosenbergi  

Microsoft Academic Search

To maximize the period where body temperature (Tb) exceeds ambient temperature (Ta), many reptiles have been reported to regulate heart rate (fH) and peripheral blood flow so that the rate of heat gain in a warming environment occurs more rapidly than the rate of heat loss in a cooling environment. It may be hypothesized that the rate of cooling, particularly

T. D. Clark; P. J. Butler; P. B. Frappell

2005-01-01

451

Heart Rate Variability and Exercise in Aging Women  

PubMed Central

Abstract Background Our group has shown a positive dose-response in maximal cardiorespiratory exercise capacity (VO2max) and heart rate variability (HRV) to 6 months of exercise training but no improvement in VO2max for women ?60 years. Here, we examine the HRV response to exercise training in postmenopausal women younger and older than 60 years. Methods We examined 365 sedentary, overweight, hypertensive, postmenopausal women randomly assigned to sedentary control or exercise groups exercising at 50% (4?kcal/kg/week, [KKW]), 100% (8 KKW) and 150% (12 KKW) of the National Institutes of Health (NIH) Consensus Development Panel physical activity guidelines. Primary outcomes included time and frequency domain indices of HRV. Results Overall, our analysis demonstrated a significant improvement in parasympathetic tone (rMSSD and high frequency power) for both age strata at 8 KKW and 12 KKW. For rMSSD, the age-stratified responses were: control, <60 years, 0.20?ms, 95% confidence interval (CI)?2.40, 2.81; ?60 years, 0.07?ms, 95% CI ?3.64, 3.79; 4 KKW, <60 years, 3.67?ms, 95% CI 1.55, 5.79; ?60 years, 1.20?ms, 95% CI ?1.82, 4.22; 8-KKW, <60 years, 3.61?ms, 95% CI 0.88, 6.34; ?60 years, 5.75?ms, 95% CI 1.89, 9.61; and 12-KKW, <60 years, 5.07?ms, 95% CI 2.53, 7.60; ?60 years, 4.28?ms, 95% CI 0.42, 8.14. Conclusions VO2max and HRV are independent risk factors for cardiovascular disease (CVD) mortality. Despite no improvement in VO2max, parasympathetic indices of HRV increased in women ?60 years. This is clinically important, as HRV has important CVD risk and neurovisceral implications beyond cardiorespiratory function.

Blair, Steven N.; Church, Timothy S.

2012-01-01

452

Heart rate variability in normal and pathological sleep  

PubMed Central

Sleep is a physiological process involving different biological systems, from molecular to organ level; its integrity is essential for maintaining health and homeostasis in human beings. Although in the past sleep has been considered a state of quiet, experimental and clinical evidences suggest a noteworthy activation of different biological systems during sleep. A key role is played by the autonomic nervous system (ANS), whose modulation regulates cardiovascular functions during sleep onset and different sleep stages. Therefore, an interest on the evaluation of autonomic cardiovascular control in health and disease is growing by means of linear and non-linear heart rate variability (HRV) analyses. The application of classical tools for ANS analysis, such as HRV during physiological sleep, showed that the rapid eye movement (REM) stage is characterized by a likely sympathetic predominance associated with a vagal withdrawal, while the opposite trend is observed during non-REM sleep. More recently, the use of non-linear tools, such as entropy-derived indices, have provided new insight on the cardiac autonomic regulation, revealing for instance changes in the cardiovascular complexity during REM sleep, supporting the hypothesis of a reduced capability of the cardiovascular system to deal with stress challenges. Interestingly, different HRV tools have been applied to characterize autonomic cardiac control in different pathological conditions, from neurological sleep disorders to sleep disordered breathing (SDB). In summary, linear and non-linear analysis of HRV are reliable approaches to assess changes of autonomic cardiac modulation during sleep both in health and diseases. The use of these tools could provide important information of clinical and prognostic relevance.

Tobaldini, Eleonora; Nobili, Lino; Strada, Silvia; Casali, Karina R.; Braghiroli, Alberto; Montano, Nicola

2013-01-01

453

Heart rate affects endothelial function in essential hypertension.  

PubMed

Increased heart rate (HR) is a risk factor for cardiovascular morbidity and mortality in the general population and in some clinical conditions. Endothelial dysfunction is an adverse prognostic factor for cardiovascular events. The aim of the study was to evaluate the effect of HR on central hemodynamic parameters and endothelial function in hypertension. We evaluated forearm blood flow (FBF) response to intra-arterial infusion of acetylcholine (ACh) and sodium nitroprusside (SNP) in 30 patients with HR ?60 min(-1) and 30 with HR ?80 min(-1). The FBF was measured by strain-gauge plethysmography. Transesophageal atrial pacing was used to increase the HR. Radial artery applanation tonometry and pulse wave analysis were used to derive central aortic pressures and correlate hemodynamic indices. The FBF response to ACh is lower in hypertensives with HR ?60 min(-1) than in those with HR ?80 min(-1) (10.6 ± 4.2 vs. 13.6 ± 5.1 ml × 100 ml(-1) of tissue × min(-1), P < 0.001). Vascular resistance decreases to 9.3 ± 2.8 U in patients with lower HR versus 7.2 ± 2.1 U in those with higher HR (P = 0.002). The FBF response to SNP is similar in both groups. Central systolic and pulse pressure are higher in bradycardic patients than in those with HR ?80 min(-1) (140 ± 8 vs. 131 ± 8 mmHg, P = 0.0001 and 49 ± 10 vs. 39 ± 11 mmHg, P = 0.0001). All central hemodynamic parameters decrease during incremental atrial pacing. Augmentation index is the strongest predictor of endothelial dysfunction at multivariate analysis. These findings demonstrate that low HR affects endothelium-dependent vasodilation in hypertension. Increased central aortic pressure and hemodynamic correlates seem to be the underlying mechanisms by which bradycardia interferes with endothelium-dependent reactivity. PMID:21559746

Maio, Raffaele; Miceli, Sofia; Sciacqua, Angela; Leone, Giulia Galiano; Bruni, Rosamaria; Naccarato, Paola; Martino, Francesco; Sesti, Giorgio; Perticone, Francesco

2011-05-11

454

Aberrant heart rate and brainstem BDNF signaling in a mouse model of Huntington's disease  

PubMed Central

Huntington’s disease (HD) is associated with profound autonomic dysfunction including dysregulation of cardiovascular control often preceding cognitive or motor symptoms. Brain-derived neurotrophic factor (BDNF) levels are decreased in HD brain, and restoring BDNF levels prevents neuronal loss and extends lifespan. We reasoned that heart rate changes in HD may be associated with altered BDNF signalling in cardiovascular control nuclei in the brainstem. Here we show that heart rate is elevated in HD (N171-82Q) mice at presymptomatic and early disease stages, and heart rate responses to restraint stress are attenuated. BDNF and TrkB mRNA and protein levels were significantly decreased in brainstem cardiovascular nuclei in HD mice. Central administration of BDNF restored the heart rate to control levels. Our findings establish a link between diminished BDNF expression in brainstem cardiovascular nuclei and abnormal heart rates in HD mice, and suggest a novel therapeutic target for correcting cardiovascular dysfunction in HD.

Griffioen, Kathleen J.; Wan, Ruiqian; Brown, Tashalee R.; Okun, Eitan; Camandola, Simonetta; Mughal, Mohamed R.; Phillips, Terry M.; Mattson, Mark P.

2012-01-01

455

Dynamics of heart rate parameters in students with various personal anxiety levels during computerized testing.  

PubMed

Students with low level of initial (pre-test) personal anxiety demonstrated a high level of modulating effects on the heart rate in all basic frequency ranges (VLF, LF, and HF) resulting in a greater total power of heart rate variability spectrum compared to students with high personal anxiety. The peculiarities of dynamics of heart rate variability were revealed during a real learning task, which correlated with personal anxiety level. In comparison with highly anxious students, the low-anxious group demonstrated more pronounced drop in the power of all ranges of the heart rate variability spectrum during testing followed by restoration of these power indices to initial levels after completion of the test. In contrast, the drop of the total power of the heart rate variability spectrum and in the power of its individual components persisted in students with high anxiety level even after the end of the testing. PMID:23113242

Dzhebrailova, T D; Sulejmanova, R G

2012-09-01

456

Reduction of heart rate by omega-3 fatty acids and the potential underlying mechanisms  

PubMed Central

An elevated resting heart rate is one of the strongest predictors of cardiovascular mortality and is independently associated with sudden cardiac death (SCD). Agents capable of reducing heart rate without significant side effects are therefore of particular interest for the prevention of SCD. Recent human and animal studies have shown that omega-3 fatty acids can reduce heart rate. Our work has shown that omega-3 fatty acids significantly reduce membrane electrical excitability of the cardiac myocyte by lowering its resting membrane potential and the duration of the refractory period through inhibition of ion channels. We propose that these actions may be the underlying mechanisms for the omega-3 fatty acid-induced reduction of heart rate observed in both humans and animals. The heart rate-lowering capability of omega-3 fatty acids may contribute to their preventive effect against SCD.

Kang, Jing X.

2012-01-01

457

Learned cardiac control with heart rate biofeedback transfers to emotional reactions.  

PubMed

Emotions involve subjective feelings, action tendencies and physiological reactions. Earlier findings suggest that biofeedback might provide a way to regulate the physiological components of emotions. The present study investigates if learned heart rate regulation with biofeedback transfers to emotional situations without biofeedback. First, participants learned to decrease heart rate using biofeedback. Then, inter-individual differences in the acquired skill predicted how well they could decrease heart rate reactivity when later exposed to negative arousing pictures without biofeedback. These findings suggest that (i) short lasting biofeedback training improves heart rate regulation and (ii) the learned ability transfers to emotion challenging situations without biofeedback. Thus, heart rate biofeedback training may enable regulation of bodily aspects of emotion also when feedback is not available. PMID:23894574

Peira, Nathalie; Pourtois, Gilles; Fredrikson, Mats

2013-07-23

458

On auditory evoked potentials and heart rate in man during whole-body vibration  

Microsoft Academic Search

Summary  Auditory evoked brain potentials and heart rate were recorded from three healthy male subjects during sinusoidal whole-body vibration exposure in the longitudinal (±az) direction (two intensities: I1=0.57 ms–2 r.m.s., I2=3.2 ms–2 r.m.s., frequency: 4 Hz) and under no-vibration control conditions according to a change-over design. All conditions were performed at a constant noise level. The part of vibration-synchronous activity contaminating

P. Ullsperger; H. Seidel

1980-01-01

459

Changes in heart rate recovery after high-intensity training in well-trained cyclists  

Microsoft Academic Search

Heart rate recovery (HRR) after submaximal exercise improves after training. However, it is unknown if this also occurs in\\u000a already well-trained cyclists. Therefore, 14 well-trained cyclists (VO2max 60.3 ± 7.2 ml kg?1 min?1; relative peak power output 5.2 ± 0.6 W kg?1) participated in a high-intensity training programme (eight sessions in 4 weeks). Before and after high-intensity training,\\u000a performance was assessed with a peak power output test including respiratory gas

Robert P. Lamberts; Jeroen Swart; Timothy D. Noakes; Michael I. Lambert

2009-01-01

460

Decreased heart rate variability in survivors of sudden cardiac death not associated with coronary artery disease.  

PubMed Central

BACKGROUND--Although heart rate variability has already been studied in survivors of sudden cardiac death secondary to coronary artery disease, an assessment of heart rate variability in survivors of sudden cardiac death not associated with coronary artery disease has not been made. METHODS--10 patients with aborted sudden cardiac death not associated with coronary artery disease (seven patients with primary ventricular fibrillation and three with unclassified mild cardiomyopathy) underwent two channel 24 hour Holter monitoring in a drug free state. All subjects were in sinus rhythm and had normal atrioventricular conduction and normal cardiac function. Spectral heart rate variability was analysed on a Holter analysis system and was expressed as total (0.01-1.00 Hz), low (0.04-0.15 Hz) and high (0.15-0.40 Hz) frequency components for each hour. Heart rate variability index was calculated for the 24 hour periods. 10 age and sex matched healthy subjects were taken as a control group. RESULTS--The spectral heart rate variability over 24 hours was significantly lower in survivors of sudden cardiac death than in controls (total 38(15) v 48(14) ms; low, 25(11) v 32(13) ms; and high, 13(8) v 18(8) ms; p < 0.05 for all comparisons). The differences in the ratio of low/high (2.19(0.76) v 1.98(0.50), p = 0.132), mean heart rate (77(12) v 69(12) beats/min, p = 0.070), and heart rate variability index (38(12) v 44(16), p = 0.287) over 24 hours between survivors of sudden cardiac death and controls did not reach significance. Comparisons of the hourly heart rate variability over the 24 hour period between the two groups showed that the differences in all components of heart</