Abstract The traditional methods of analysing heart rate variability based on means and variance are unable to detect subtle but potentially important changes in interbeat heart rate behaviour. This research was designed to evaluate the clinical applicability and prognostic significance of new dynamical methods of analysing heart rate behaviour derived from nonlinear mathematics. The study covered four different patient populations, their controls and one general population of elderly people. The first patient group consisted of 38 patients with coronary artery disease without previous myocardial infarction, the second of 40 coronary artery disease patients with a prior Q-wave myocardial infarction, and the third of 45 patients with a history of ventricular tachyarrhythmia. The fourth group comprised 10 patients with a previous myocardial infarction who had experienced ventricular fibrillation during electrocardiographic recordings. The fifth group comprised a random sample of 347 community-living elderly people invited for a follow-up of 10 years after electrocardiographic recordings. Heart rate variability was analysed by traditional time and frequency domain methods. The new dynamical measures derived from nonlinear dynamics were: 1) approximate entropy, which reflects the complexity of the data, 2) detrended fluctuation analysis, which describes the presence or absence of fractal correlation properties of time series data, and 3) power-law relationship analysis, which demonstrates the distribution of spectral characteristics of RR intervals, but does not reflect the magnitude of spectral power in different spectral bands. Approximate entropy was higher in postinfarction patients (1.17 ± 0.22), but lower in coronary artery disease patients without myocardial infarction (0.93 ± 0.17) than in healthy controls (1.03 ± 014, p < 0.01, p < 0.05 respectively). It did not differ between patients with and without ventricular arrhythmia. The short term fractal-like scaling exponent of the detrended fluctuation analysis was higher in coronary artery disease patients without myocardial infarction (1.34 ± 0.15, p < 0.001), but not in postinfarction patients without arrhythmia (1.06 ± 0.13) compared with healthy controls (1.09 ± 0.13). The short term exponent was markedly reduced in patients with life-threatening arrhythmia (0.85 ± 0.25 ventricular tachycardia patients, 0.68 ± 0.18 ventricular fibrillation patients, p < 0.001 for both). The long term power-law slope of the power-law scaling analysis was lower in the ventricular fibrillation group than in postinfarction controls without arrhythmia risk (-1.63 ± 0.24 vs. -1.33 ± 0.23, p < 0.01) and predicted mortality in a general elderly population with an adjusted relative risk of 1.74 (95% CI 1.42–2.13). The present observations demonstrate that dynamic analysis of heart rate behaviour gives new insight into analysis of heart rate dynamics in various cardiovascular disorders. The breakdown of the normal fractal-like organising principle of heart rate variability is associated with an increased risk of mortality and vulnerability to life-threatening arrhythmias.

Abstract Ischemic stroke is associated with cardiovascular autonomic nervous system (ANS) disturbances, including reduced heart rate (HR) variability and acute phase neurohumoral activation with elevated stress hormone levels. The impact of HR variability and neurohumoral factors such as natriuretic peptides on the long-term survival of patients with ischemic stroke has not been studied previously. This study was designed to evaluate cardiovascular autonomic regulation in ischemic stroke patients by assessing HR dynamics and various neurohumoral factors. The values of the assessed variables in predicting mortality were evaluated. HR variability assessments were performed in the acute phase of ischemic stroke and for a general elderly population. Various neurohumoral factors were also assessed in the acute phase of stroke. After follow-up, the survival of the subjects was assessed and the prognostic values of the measured factors were evaluated. Stroke patients were found to have cardiovascular autonomic and hormonal disturbances manifested as reduced traditional time and frequency domain measures of HR variability, altered long-term HR dynamics and elevated levels of natriuretic peptides in the acute phase. Altered long-term HR dynamics in the acute phase of stroke predicted long-term mortality after stroke and cerebrovascular mortality in the general elderly population. Neuroendocrine activation involving elevated natriuretic peptide values that were associated with high cortisol and catecholamine levels was observed in the acute phase of ischemic stroke. Neurohumoral disturbance was prognostically unfavourable. The most powerful predictors of poststroke mortality were altered long-term HR dynamics and elevated levels of natriuretic peptides and cortisol, which predicted mortality independently of the conventional risk factors in multivariate analysis. Prognostically unfavourable cardiovascular autonomic dysfunction with disturbances in the long-term behaviour of HR dynamics was found to be related to ischemic stroke. Neurohormonal activation with elevated natriuretic peptide and cortisol levels in the acute phase predicts long-term mortality after ischemic stroke.

>Magister Scientiae - MSc / Leonotis leonurus (L. Leonurus) has relatively abundant diterpenes and has been used as a traditional herbal medicine for treating several ailments including influenza, muscular cramps, skin related diseases, menstrual, antilipidemic, hyperglycaemia and hypertension. In this study, diterpenoid compounds such as; Dubiin, SaponifiedDubiin, Hispanol, Marrubiin and DC9 were isolated from L. Leonurus plant. The cardiovascular effects of these isolated compounds were investigated in order to determine the response of anaesthetised normotensive Wistar rats (in-vivo) to the compounds. Also, the druglikeness of the isolated diterpenoid compounds and their binding interaction with β1 adrenoceptor (PDB: 2Y04), angiotensin II receptor (Ang II) (PDB: 3R8A), Angiotensin converting enzyme (ACE) (PDB: 4XX3), and renin receptor (PDB: 2X8Z) by using molecular docking methods and Chemoinformatics analysis was performed (in-silico). Important molecular descriptors and molecular docking were used in our Chemoinformatics (in-silico) analysis to study the druglikeness and the binding affinity for of each molecule (Dubiin, SaponifiedDubiin, Hispanol, Marrubiin and DC9). The molecular descriptors and the binding energy were calculated by using the molecular operating environment software (MOE 2013). The lowest energy and highest cluster conformations of the molecules were further analysed. All the five (5) diterpenoids were predicted to have good oral bioavailability after oral administration and passed the BloodBrain Barrier (BBB) rules. Also, the compounds were predicted to have high probability of being good Druglike candidates, except for DC9, which is predicted to have lower possibilities of being Druglike candidate than the other diterpenoids. Furthermore, these compounds (Dubiin, SaponifiedDubiin, Hispanol, Marrubiin and DC9) were shown to interact with β1 adrenoceptors in-silico, an interaction that was confirmed in-vivo by increases in Blood pressure (SP, DP and MAP) and Heart rate (HR). In anaesthetized normotensive male Wistar rats (in-vivo), Dubiin (0.5 40mg/kg; IV), SaponifiedDubiin (0.5 60mg/kg; IV) Hispanol (0.5 40mg/kg; IV), DC9 (0.5 40mg/kg; IV) and Marrubiin (0.5 40mg/kg; IV) produced dose dependent increase in Systolic pressure (SP), Diastolic pressure (DP), and Mean arterial pressure (MAP) at all doses. Also, the compounds produced dose dependent increase in Heart rate (HR). From the in-vivo and in-silico studies it can be concluded that all the five (5) isolated diterpenoid compounds showed cardiovascular effects on Blood pressure (BP) and Heart rate (HR) by acting as β1 adrenoceptor agonists. Also, these diterpenoids compounds could be responsible for the cardiovascular effect observed in the methanol extracts from previous studies. These cardioactive compounds are prototype or ''lead compounds'' for designing and developing new nontoxic and effective drugs for cardiovascular disease (CVD) treatment.

Monitoring of women in labour is an important aspect of the practice of the health care professionals working in the labour ward. The pregnancy of a woman mightappear to be normal but it is not possible to predict the positive outcome of labour until the baby is born because foetal distress can occur suddenly or other problems can arise during the course of labour. Doctors need to closely monitor the progress of labour of all the women regardless of whether he pregnancy is rated low risk or not. The use of Cardiotocography (CTG) during labour thus becomes critical. In the current study the perceptions of the doctors working in labour ward units will be explored and described in order to recommend activities that could optimize the use of CTG by doctors as an intrapartum monitoring tool. A qualitative research design will be used and the data collection method will be by means of semi-structured audio-taped one-on-one interviews.

Driving can be a stressful task, especially under congestion conditions. Several studies have shown a positive correlation between stress and aggressive behaviour behind the wheel, leading to accidents. One common way to minimize stress while driving is to avoid highly congested roads. However, not all drivers show the same response towards high traffic situations or other road conditions. For instance, some drivers may prefer congested routes to longer ones to minimize travel time. Increasingly, drivers are employing Advanced Traveller Information Systems while commuting to both familiar and unfamiliar destinations, not just to obtain information on how to reach a certain endpoint, but to acquire real-time data on the state of the roads and avoid undesired traffic conditions. In this thesis, we propose an Advanced Traveller Information System that personalizes the driver’s route using their road preferences and measures their physiological signals during the trip to assess mental stress. The system then links road attributes, such as number of lanes, speed limit, and traffic severity, with the driver’s stress levels. Then, it uses machine learning to predict their stress levels on similar roads. Hence, routes that contribute to high-levels of stress can therefore be avoided in future trips. The average accuracy of the proposed stress level prediction model is 76.11%.

No description available.

Orexin A and B, two recently isolated hypothalamic peptides, have been reported to increase food consumption upon intracerebroventricular injections in rats. In addition to the hypothalamus, orexin A-immunoreactive fibers have been observed in several areas of the medulla that are associated with cardiovascular functions. The present study was undertaken to evaluate the hypothesis that orexins may influence cardiovascular response by interacting with neurons in the medulla. Intracisternal injections of orexins A (0.0056- 7.0 nmol) or B (0.028-0.28 nmol) dose dependently increased mean arterial pressure (MAP) by 4-27 mmHg and heart rate (HR) by 26-80 beats/min in urethan-anesthetized rats, with orexin A being more effective in this regard. MAP and HR were not changed by intravenous injection of orexins at higher concentrations. Microinjection of orexin A (14 pmol/50.6 nl) to the rostral ventrolateral medulla, which was confirmed by histological examination, increased MAP and HR. Our results indicate that, in addition to a role in positive feeding behavior, orexins may enhance cardiovascular response via an action on medullary neurons.

Published by Oxford University Press on behalf of the International Epidemiological Association. Background: To investigate the association between resting heart rate and the risk of developing impaired fasting glucose (IFG), diabetes and conversion from IFG to diabetes. Methods: The prospective analysis included 73 357 participants of the Kailuan cohort (57 719 men and 15 638 women). Resting heart rate was measured via electrocardiogram in 2006. Incident diabetes was defined as either the fasting blood glucose (FBG) ≥ 7.0 mmol/l or new active use of diabetes medications during the 4-year follow-up period. IFG was defined as a FBG between 5.6 and 6.9 mmol/l. A meta-analysis including seven published prospective studies focused on heart rate and diabetes risk, and our current study was then conducted using random-effects models. Results: During 4 years of follow-up, 17 463 incident IFG cases and 4 649 incident diabetes cases were identified. The corresponding adjusted hazard ratios (HRs) for each 10 beats/min increase in heart rate were 1.23 [95% confidence interval (CI): 1.19, 1.27] for incident diabetes, 1.11 (95% CI: 1.09, 1.13) for incident IFG and 1.13 (95% CI: 1.08, 1.17) for IFG to diabetes conversion. The risks of incident IFG and diabetes were significantly higher among participants aged < 50 years than those aged ≥ 50 years (P-interaction < 0.02 for both). A meta-analysis confirmed the positive association between resting heart rate and diabetes risk (pooled HR for the highest vs lowest heart rate quintile=1.59, 95% CI:1.27, 2.00; n=8). Conclusion: Faster resting heart rate is associated with higher risk of developing IFG and diabetes, suggesting that heart rate could be used to identify individuals with a higher future risk of diabetes.

The development of perceptual-cognitive processes during infancy has been traditionally studied using visual habituation and paired-comparison techniques. There has been extensive work within the field of infant attention that has focused on the development of visual attention. Within this field, it has been well established that there are two distinct classifications of infants' visual behavior; infants with short visual fixations who perform well in a recognition task following familiarization and infants with long visual fixation with impaired performance. There are two hypotheses for the differences underlying these groups. First, that visual fixation duration is reflective of the speed of information processing such that long-looking infants process information more slowly than short-looking infants. The second hypothesis is that infants who are long-looking have difficulty disengaging and shifting their attention to another location. There has not been any work exploring how these differences manifest themselves in other modalities. Thus, this project has three purposes: (1) to explore whether group differences emerge in an auditory recognition task similar to those found in the visual recognition phase of the paired-comparison task, (2) to better understand how performance differences in the visual task correspond to any observed differences in an auditory task, and (3) to identify any potential mechanisms which may account for the observed differences in group performance on an auditory task. / Ph. D.

Emotion regulation is processes by which individuals influence which emotions they have, when they have them, and how they experience and express those emotions. In the field of developmental psychology, there is a large literature on affect regulation focused almost exclusively on infants and young children with a focus on temperamental differences in reactivity, both affective and physiological, and accompanying regulatory strategies. The purpose of the current study was to examine the role of two dimensions of temperament, negative affect (NA) and effortful control (EC), and how these dimensions relate to physiology, self-report of emotion, and behavior during resting and stressor tasks (Stroop, video game, hand cold pressor, and delayed gratification), the latter in which emotion suppression instructions were given. Using the Adult Temperament Questionnaire (ATQ) to screen 656 subjects, 24 males and 53 females were recruited to take part in the second phase of the study, creating four groups with their screening ATQ scores: high NA/high EC, low NA/low EC, high NA/low EC, low NA/high EC. Physiological measures derived from electrocardiogram (ECG) and impedance cardiography were recorded during each task and behaviors were coded using the Emotion Expressive Behavior Coding System. EC Group and NA Group were not significant for the majority of the physiological, self-report, and behavioral variables. However, the EC subscale inhibitory control was predictive of lower resting HRV for females only, and the Extraversion/Surgency subscale Sociability was a significant predictor of cardiac sympathetic activity during the tasks, with low sociability subjects showing a stronger sympathetic response. Neither self-report of emotion nor behavioral variables show a clear group difference in response to the tasks. Future studies will examine the use of other types of regulatory tasks, such as social interactions, as well as the need for a balance between emotion expressivity and emotion regulation. / Ph. D.