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Behaviour, heart rate, and heart rate variability in pigs exposed to novelty

Behaviour, heart rate, and heart rate variability in pigs exposed to novelty

ABSTRACT - In the present study, we investigated behavioural responses and determined parameters of heart rate variability (HRV) to elucidate a relative activation of autonomic nervous system (ANS) during baseline (10 min) and in response to potentially stressful situations (10 min) in two pig breeds and sexes. Gilts (n = 21) and barrows (n = 9) of the Landrace × Yorkshire (LY; n = 15) and Landrace/Yorkshire × Landrace/Duroc (LYLD; n = 15) breeds were subjected to a novel object test (NOT) and a novel arena test (NAT). Basal ANS state differed in pigs across breeds but not sexes. Landrace × Yorkshire pigs had a significantly lower basal heart rate (HR) and low-frequency band (LF) with a higher root mean square of successive interbeat intervals (RMSSD) and high-frequency band (HF) than LYLD pigs. In the NOT, despite having similar cardiac responses, gilts had a longer duration of contact with a novel object, higher lying and standing duration, and a lower duration of walking compared with barrows. In the NAT, we found similar behaviour across sexes but a different degree of ANS state, with barrows having a significantly higher increase in LF/HF (power of the low frequency component divided by the power of the high-frequency band) compared with gilts. Landrace/Yorkshire × Landrace/Duroc pigs showed longer duration of contact with a novel object in the NOT accompanied by less lying and standing than LY pigs in both tests. No difference in ANS activation between breeds was found in the NOT. In the NAT, HR increased more from baseline to testing in LY pigs than in LYLD pigs. There is a complex and often contradictory nature of relationships between behaviour and cardiac responses to novelty in pigs of different breeds and sexes.
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Nonlinear indices of heart rate variability during endodontic treatment

Nonlinear indices of heart rate variability during endodontic treatment

Abstract: Dental treatment promotes psychosomatic change that can inluence the procedure and compromise the general well-being of the patient. In this context, it highlights the importance of evaluating the function of the autonomic nervous system in individuals undergoing endodontic treatment. Thus, this manuscript aimed to analyse cardiac autonomic modulation, through non-linear indices of heart rate variability (HRV) during endodontic treatment. Analysis of 50 subjects of either sex aged between 18 and 40 years diagnosed with irreversible pulp necrosis of lower molars undergoing endodontic treatment was undertaken. We carried out fractal and symbolic analysis of HRV, which was recorded in the irst session of the endodontic treatment at four intervals: T1: 0-10 min before the onset of the treatment session; T2: 0–10 min after the application of anaesthesia; T3: throughout the period of treatment; and T4: 0-30 min after the end of the treatment session. There was reduction of α1 in T2 compared to T1 and T4 (p < 0.0001). The α2 index also reduced in T2 compared to T3 (p = 0.0035). There was an increase in the α1/α2 ratio in T4 compared to T2 and T3 (p = 0.0003). It was found that 0V% was signiicantly lower in T2 (p = 0.002), while 2UV% was signiicantly higher (p < 0.0001) when compared to other points in time. In conclusion, HRV is reduced during endodontic treatment, and after applying local anaesthetic the parasympathetic component of HRV increases. These data indicate that endodontic treatment acutely overcharges the heart, supporting the stress involved in this situation.
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Chronic obstructive pulmonary disease and heart rate variability: a literature update

Chronic obstructive pulmonary disease and heart rate variability: a literature update

In order to analyze HRV after two exercise programs in patients with COPD, Camillo and coworkers [19] assessed 40 patients divided into two groups: high inten- sity, characterized by endurance exercise and strength, and of low intensity, that consisted of calisthenics and breathing exercises for a period of 3 months. Cardiac autonomic control was assessed before and after 3 months of training and, was judged during rest and as a response to an orthostatic stimulus using a head-up tilt test following a previous published protocol. Patients were positioned on an orthostatic table where they ini- tially stayed for 10 minutes in supine position. The table was then lifted 75°, and this was followed by a period of more 10 minutes in orthostatic position. The authors concluded that three months of high-intensity exercise training enable an important improvement in post- training cardiac autonomic function in patients with COPD. Additionally, better baseline values of upper limbs muscle force, physical activity in daily life and total heart rate variability may help predicting those patients who will more likely improve their cardiac autonomic function after a high-intensity exercise training program. An important study [15] attempted to investigate the effect of pulmonary rehabilitation on heart rate variabil- ity during exercise in patients with COPD. Beyond, the effect of pulmonary rehabilitation on health-related quality of life and exercise capacity concurrently. Cardiac autonomic control was measured with a total recording time of 5 minutes at rest and at peak exercise and, were obtained from the ECG signals. The protocol program consisted of 12-week outpatient-based program with two sessions per week. Before all training sessions, patients went through prior educational training, then the lower limb cycle ergometer exercise was performed. The train- ing protocol of the lower limb exercise consisted of warm up of 4 minute, followed by 60-100% peak VO 2
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Heart rate variability under resting conditions in postmenopausal and young women

Heart rate variability under resting conditions in postmenopausal and young women

The aim of the present study was to compare the modulation of heart rate in a group of postmenopausal women to that of a group of young women under resting conditions on the basis of R-R interval variabil- ity. Ten healthy postmenopausal women (mean ± SD, 58.3 ± 6.8 years) and 10 healthy young women (mean ± SD, 21.6 ± 0.82 years) were submitted to a control resting electrocardiogram (ECG) in the supine and sitting positions over a period of 6 min. The ECG was obtained from a one-channel heart monitor at the CM5 lead and processed and stored using an analog to digital converter connected to a microcom- puter. R-R intervals were calculated on a beat-to-beat basis from the ECG recording in real time using a signal-processing software. Heart rate variability (HRV) was expressed as standard deviation (RMSM) and mean square root (RMSSD). In the supine position, the postmeno- pausal group showed significantly lower (P<0.05) median values of RMSM (34.9) and RMSSD (22.32) than the young group (RMSM: 62.11 and RMSSD: 49.1). The same occurred in the sitting position (RMSM: 33.0 and RMSSD: 18.9 compared to RMSM: 57.6 and RMSSD: 42.8 for the young group). These results indicate a decrease in parasympathetic modulation in postmenopausal women compared to young women which was possibly due both to the influence of age and hormonal factors. Thus, time domain HRV proved to be a nonin- vasive and sensitive method for the identification of changes in autonomic modulation of the sinus node in postmenopausal women.
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Cognitive performance and heart rate variability: the influence of fitness level.

Cognitive performance and heart rate variability: the influence of fitness level.

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.
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Geometric index of heart rate variability in chronic obstructive pulmonary disease

Geometric index of heart rate variability in chronic obstructive pulmonary disease

28. Kulur AB, Haleagrahara N, Adhikary P, Jeganathan PS. Effect of diaphragmatic breathing on heart rate variability in ischemic heart disease with diabetes. Arq Bras Cardiol. 2009;92:423---9. 29. Tuncer M, Gunes Y, Guntekin U, Gumrukcuoglu HA, Eryonucu B, Guler N, et al. Heart rate variability in patients with iron deficiency anemia. Arq Bras Cardiol. 2009;92:368---71. 30. Vanderlei LC, Pastre CM, Freitas Jr IF, Godoy MF. Geometric

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Ecg artifacts and poincare plot based heart rate variability

Ecg artifacts and poincare plot based heart rate variability

Abstract: The analysis of beat to beat fluctuations of heart rate known as heart rate variability (HRV) become a non- invasive clinical research tool to study the modulation that the autonomic nervous system exerts on the cardiovascular system. The missing RR intervals contribute a serious limitation to HRV analysis. The linear HRV measures are very sensitive to ECG artifacts. The objective of present study was to evaluate the robustness of Poincaré plot analysis in presence of missing RR intervals. Poincaré plot is a visual tool in which each RR interval is plotted as a function of previous RR interval. The Poincaré plot provides summary as well as detailed beat-to-beat information on the behavior of the heart. The study involves RR interval time-series data of 25 healthy volunteers. The ectopic free RR interval tachograms with length N=1000 were derived from Lead-II ECG recordings having a sampling frequency of 500 Hz. In each data set, consecutive RR interval data were randomly selected for removal, and the data length removed was increased from 0 to 100 RR intervals in an increment of 5 RR intervals. Two random selections of RR intervals were made to analyze the average effects of the missing data. In each case, the Poincaré plot (SD1 and SD2) based HRV parameters were calculated. Mean relative errors were found to be less than 1.8 for SD1 and SD2 even in the presence of 100 missing RR intervals. Poincaré plot parameters are found to be more robust than linear measures to missing RR intervals.
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Ultra-short-term heart rate variability during resistance exercise in the elderly

Ultra-short-term heart rate variability during resistance exercise in the elderly

Heart rate variability (HRV) analysis provides a quantifi- cation of heart rate (HR) and beat-to-beat fluctuations, and is the most frequently used approach to assess cardiac autonomic balance (1). HRV analysis is a simple, inexpen- sive, and well-validated tool that provides, among others, significant prognosis markers for coronary heart disease (2), cardiac (3) and all-cause mortality, all of which can be calculated in resting conditions (4). HRV indices have been used to assess the autonomic HR control in physiological conditions, including exercise for adult and elderly sub- jects (5–8). Furthermore, studies show that HRV analysis is an important tool for exercise prescription and for the evaluation of adaptations to exercise training (9).
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Physical activity as a health factor modifying heart rate variability (HRV)

Physical activity as a health factor modifying heart rate variability (HRV)

, a period of a high physical activity, in the volleyball players’ group, growth trends of the sympathetic part tension appeared in comparison to the pre-competition period. According to Iellamo F. et al. [20] growth of the sympathetic component, as a result of an intensified physical activity confirms good contestants’ preparation for starts and achieving high performances. Authors quoted above state that longer maintaining of sympathicotonia can contribute to contestants’ overtraining. Mourot L. et al. [39] confirm that too intensive trainings are connected with a balance shift in AUN towards sympathetic direction. The authors examined persons of a different physical activity (8 healthy men, 8 training, 7 with overtraining symptoms). On the base of the researches and the obtained results, it has been stated that the contestants with the overtraining symptoms showed an increase in sympathetic activity accompanied by the drop in parasympathetic activity and total power. Such a situation is connected with an overtraining of the Basedow type, which can appear with contestants [40]. Together with the training intensity reduction, the balance in AUN is restored. Nowosielska-Swadźba D [38]. examined boys aged 14- 16 training athletics, volleyball and swimming. The results were compared to the physically inactive control group. A small domination of the sympathetic part has been marked in the control group. However, in the swimmers’ group, subjected to more physical load, there has been a trend reversal, from a characteristic vagotonia to sympathicotonia. In our own research, in the control group, with the sympathetic domination, a shortened RR intervals have been observed and a high frequency of the heart rate in comparison to volleyball players group. LF and LF/HF factors testify the balance shift towards sympathetic direction in the control group. In the control group, the average value of the heart rate was 101,3/min and it was 41,1 beats higher in comparison to the people training volleyball. In the control group, sympathetic predominance, low total power value may be the result of the reduced physical activity [2]. Karjalainen j. et al. [41] write that tachycardia is caused, among others, by an increased activity of the sympathetic system. Rajab M. et al. [42] state that the reduction of high-frequency component (HF) in the total heart rate variability may be a diabetes complication, a risk factor for a sudden death.
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Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate variability

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

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

Heart rate variability and arrhythmias evaluated with Holter in dogs with degenerative mitral valve disease

Cardiac diseases promote alterations in the autonomic control of the heart, leading to an increase in heart rate and, as a result, a decrease in heart rate variability (HRV).The aim of this study was to evaluate if the development of heart failure secondary to degenerative mitral valve disease (DMVD) concurs with changes in autonomic modulation of heart rhythm which are assessed by long electrocardiography examination (Holter). Dogs were evaluated by clinical examination and echocardiography in order to be categorized into the following groups: Control (healthy; n=6), DMVD (disease without heart failure; n=8), and DMVD heart failure (disease with heart failure; n=13). Arrhythmias and frequency domain HRV were determined by Holter. Diseased animals, when compared to healthy, had significantly lower total power, which indicates overall HRV. DMVD heart failure dogs also showed other disturbances such as high incidence of supraventricular arrhythmias, high heart rate, little amount of pauses (2.0s long between consecutive heartbeats), longer time in tachycardia, shorter time in bradycardia, low high frequency (parasympathetic control), and high low frequency (sympathetic and parasympathetic control) when compared to control (p<0.05). In DMVD dogs, Holter-derived variables changed with the development of heart failure. Keywords: electrocardiography, heart failure, frequency-domain, cardiology
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Heart rate variability in normal and pathological sleep

Heart rate variability in normal and pathological sleep

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

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

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

Gaussian mixture model of heart rate variability.

Because of this experimental evidence spectral analysis has become an increasingly popular method to investigate heart rate variability because it provides the basic information of how power distributes as a function of frequency. Spectral analysis enables to identify and measure the principal rhythmical fluctuations that characterise the R{R time series and contain physiological information; further, it has has been proven to provide important and accurate information on sympathetic and vagal modulation of sinus node in normal subjects and in patients with a variety of organic heart diseases, see, for instance, [1].
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Influence of heart failure severity on heart rate variability

Influence of heart failure severity on heart rate variability

Heart rate variability in healthy controls and heart failure patients classified in NYHA functional classes. VLF =ǓǢǝǠǟǚǣǜǑǦǢǗǜǓǗǟǨǚǹǑ LF =ǟǚǣǜǑǦǢǗǜǓǗǟǨǚǹǑ HF =ǓǚǣǠǜǑǦǢǗǜǓǗǟǨǚǹǑ Tot Powe[r]

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Autonomic nervous system response to remote ischemic conditioning: heart rate variability assessment

Autonomic nervous system response to remote ischemic conditioning: heart rate variability assessment

Background: Remote ischemic conditioning (RIC) is a procedure applied in a limb for triggering endogenous protective pathways in distant organs, namely brain or heart. The underlying mechanisms of RIC are still not fully understood, and it is hypothesized they are mediated either by humoral factors, immune cells and/or the autonomic nervous system. Herein, heart rate variability (HRV) was used to evaluate the electrophysiological processes occurring in the heart during RIC and, in turn to assess the role of autonomic nervous system. Methods: Healthy subjects were submitted to RIC protocol and electrocardiography (ECG) was used to evaluate HRV, by assessing the variability of time intervals between two consecutive heart beats. This is a pilot study based on the analysis of 18 ECG from healthy subjects submitted to RIC. HRV was characterized in three domains (time, frequency and non-linear features) that can be correlated with the autonomic nervous system function.
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State Anxiety and Nonlinear Dynamics of Heart Rate Variability in Students.

State Anxiety and Nonlinear Dynamics of Heart Rate Variability in Students.

The hallmark of physiological systems is their extraordinary complexity [56]. Experimental and theoretical evidence suggests that under healthy conditions physiological signals may have a fractal temporal structure [57]. Introduced by Peng and collaborators [58], DFA has become a widely used technique for the determination of (mono-) fractal scaling properties and the detection of long-range correlations in noisy, non-stationary time series. DFA is a scaling anal- ysis method that involves the calculation of a simple quantitative parameter—the scaling expo- nent α—to represent the correlation properties of a signal. The DFA method may be useful in identifying and quantifying different states of the same system according to its different scaling behaviors. For example, the scaling exponent α for heart interbeat intervals differs between normal and pathological conditions [59]. DFA was originally used to analyze 24-hr Holter recordings [58], but it is impractical for assessing HRV stress responses. Recent studies have reported the susceptibility of short-term HRV to DFA [60]; this was the basis for computation of DFA measures for a 5-min RR sequence. Unmedicated patients with major depressive disor- der had a significantly increased DFA when compared with controls [35]. Pre-competitive anx- iety is associated with an increased level of the short-term scaling exponent (α1) [54].
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Analysis of heart rate variability in a rat model of induced pulmonary hypertension

Analysis of heart rate variability in a rat model of induced pulmonary hypertension

were preferred at our laboratory, as they seemed to be more sensi- tive to MCT than males. Another aspect that probably contributed to the large intra- and inter-rat variations, that should be consid- ered in future studies, was the type of instrumentation used to record HR, implying anesthesia with Ketamine and rat manipu- lation. Ketamine induces a state of sedation, immobility, amnesia and marked analgesia. At pulmonary level, ketamine has no effects in pulmonary vascular resistance. It induces an increase in arte- rial blood pressure, cardiac output and heart rate. This effect is attributed to an increase in sympathetic activity [22]. Hopefully, this should be substituted by telemetric HR recording avoiding anesthesia and minimizing artificial rat manipulation and instru-
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Analysis of heart rate variability on diabetic patients

Analysis of heart rate variability on diabetic patients

In both experiments described in the next sections, the biomedical signals selected were ECGs collected from The PTB Diagnostic data base and only thirty seconds of that data was considered, which contains 549 records from 290 subjects (aged 17 to 87, mean 57.2; 209 men, mean age 55.5, and 81 women, mean age 61.6 with different heart diseases. PTB is an abbreviation for Physikalisch-Technische Bundesanstalt, the National Metrology Institute of Germany, which has provided this digitized ECGs for research. The sampling frequency in this database is 1000 Hz [13].

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Rev. Nutr.  vol.30 número1

Rev. Nutr. vol.30 número1

DARK CHOCOLATE AND HEART RATE VARIABILITY | 145. Rev.[r]

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