No description available.

Thesis (MMed)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Introduction - Accurate computerized analysis of the fetal heart rate (FHR) pattern has become more feasible and clinically relevant in recent years. Taking into account advances in neonatal care resulting in a declining lower limit for fetal viability as well as research into fetal effects of maternal high risk behaviour and escalating intra-uterine exposure to harmful toxins and drugs, fetal heart rate patterns need to be more accurately described in earlier gestations than what is currently available in literature. With advancing technology it is becoming possible to accurately record and interpret the FHR patterns from gestations as early as 20 weeks' gestation. By using the Monica AN24 transabdominal electrocardiographic fetal monitor and product specific software, we analysed early FHR patterns according to the Dawes-Redman criteria, as used in later gestations. Methods - The aim of our study was to describe patterns of FHR (short-term variability, basal heart rate, accelerations and decelerations) at 20-24 weeks' gestation. Physiological data were obtained from the routine second trimester fetal assessment by the Monica AN24 monitor as used in the Safe Passage Study. As of December 31, 2009, 411 participants completed their first fetal assessment and met our inclusion criteria. Because our aim was the description of patterns in pregnancies with a normal outcome, we excluded all adverse neonatal outcomes, preterm deliveries, babies with low birth weights as well as cases where delivery data were lost. After recordings of poor technical quality were also removed from our data pool, 281 recordings remained for analysis. Results - Distinct FHR patterns and quantifiable parameters of heart rate variability were consistently observed. In contrast to what has previously been published, accelerations of the FHR and reassuring baseline variation are present from as early as 20 weeks. Conclusion - Information from this study provides an important foundation for further studies of early FHR patterns and it will help us better assess the fetus at a crucial age for indicators of good outcome at early delivery. / AFRIKAANSE OPSOMMING: Inleiding - Akkurate gerekenariseerde ontleding van die fetale hartpatroon het in die afgelope paar jaar meer tegnologies haalbaar met toenemende kliniese toepassing geword. Tans ervaar ons besondere vooruitgang in neonatale sorg en dus dalende grense vir vroeë lewensvatbaarheid in kliniese praktyk. Daar is ook 'n toename in navorsing oor moederlike hoë risiko gedrag tydens swangerskap en die effek hiervan op die ontwikkeling die fetus asook die neonatale uitkomste. Akkurater beskrywing van fetale hartpatrone in vroeëre gestasies as wat huidiglik in die literatuur beskikbaar is, is dus genoodsaak om die effekte van blootstelling op die fetus waar te neem. Met vooruitgang in tegnologie is dit nou moontlik om deur nie-indringende elektrokardiografie, fetale hartpatrone te registreer en te interpreteer van so vroeg as 'n swangerskapsdurte van 20 weke. Deur die gebruik van die Monica AN24 transabdominale monitor en produk-spesifieke programmatuur, kon ons vroeë fetale hartpatrone ontleed volgens die Dawes-Redman kriteria wat gewoonlik in later swangerskapsduurtes gebruik word. Metodes - Die doel van ons studie was die beskrywing van verskeie fetale hartpatrone (naamlik korttermyn variasie, basale hartspoed, versnellings asook vestadigings) rondom 20 – 24 weke swangerskapsduurte. Fisiologiese data is in die tweede trimester verkry deur die Monica AN24 monitor, soos gebruik word in die voortgaande Veilige Geboorte Studie by Tygerberg hospitaal. Tot en met 31 Desember 2009, het 411 deelnemers hulle eerste fetale evaluasie vir die Veilige Geboorte Studie gehad en ook voldoen aan die insluitingskriteria van hierdie projek. Aangesien ons fokus die beskrywing van hartpatrone in normale swangerskappe was, het ons alle nie-wenslike neonatale uitkomste, voortydse verlossings, babas met lae geboorte gewig asook gevalle waarvan die geboortedata nie beskikbaar was nie, uitgesluit. Alle opnames met sub-standaard tegniese kwaliteit is ook verwyder uit ons finale data vir ontleding, wat ons met 281 opnames gelaat het vir hierdie studie. Resultate - Duidelike fetale hartpatrone en meetbare afmetings is deurgangs opgemerk. In teenstryd met wat voorheen gedokumenteer is, is die teenwoordigheid van versnellings asook gerusstellende basislyn variasie meetbaar vanaf 20 weke gestasie. Samevatting - Informasie vanaf hierdie studie verskaf 'n belangrike grondslag vir verdere projekte in die ontleding van fetale hartpatrone met die fokus op ondersoek van vroeë voorspelling van goeie neonatale uitkomste.

The change in R-R intervals between adjacent heartbeats is referred to as Heart Rate Variability (HRV). HRV data provides information regarding an individual’s Autonomic Nervous System (ANS), specifically the ANS’s two branches, the Sympathetic Nervous System (SNS) and the Parasympathetic Nervous System (PNS). The HRV of a healthy, well-conditioned heart is large at rest, while low HRV is associated with adverse health outcomes such diabetes, heart disease and early mortality. There has been a substantial amount of HRV research conducted with typically developing individuals. One group who is greatly underrepresented in research is individuals with intellectual disabilities. Currently, no studies have been undertaken with Special Olympics athletes. Therefore, the purpose of this study was to create HRV profiles at rest, during submaximal exercise, and at recovery of adult Special Olympic athletes. The study also sought to examine the impact that Down syndrome, age, sex, and medication on HRV profiles. The current study found that although heart rate responded appropriately during the three testing conditions (rest, exercise, recovery) the athletes were sympathetically dominated across all three conditions, indicating an imbalance between the SNS and the PNS. In addition, male and female athletes were significantly different with regards to low frequency and high frequency power. It is possible that anxiety or excitement about the testing influenced some athletes, and future research should examine how additional protocol familiarization could impact the HRV profiles within this population. Additionally, more research with larger sample sizes is needed to more fully understand the impact that age, etiology of intellectual disability, and medication use may be having on HRV profiles. / Graduate

The impact of colour and lighting conditions on the emotions and performance of people is gaining greater importance in our urban societies. While large resources are allocated for well designed spaces with the right choices of colour and lighting conditions, there is little scientific evidence that supports these choices. Although the literature on light and colour is extensive, it does not present a uniform set of findings for a consistent perspective on the influence of colour and light. Most of the research reported in this field uses subjective measures to study the emotional effects of light and colour on people. It has been reported in literature that emotion manifests itself in three separate sections; (i) physiological (i.e. objective measures), (ii) psychological (subjective measures), (iii) behavioral, and it is necessary that studies not be limited to the assessment of a single response but include sample measures from each of the three manifestations. This research is built on the current body of knowledge that there is a need for a study on the emotional effects of light and colour on people using physiological and psychological measures, to ensure the objectivity and reproductivity of the experiments. It is well documented in literature that there is close correlation between emotions, heart rate (HR), and skin conductance (SC). Hence HR and SC are expected to be good physiological measures of environmental conditions on people. Thus this thesis reports changes in the HR, SC and self-assessment reports of arousal and valence (SAM) for people when exposed to different colour and intensity lights. The aim is to help provide an objective rationale for the choice for light intensity and colour by architects, interior designers and other professionals. The experiments were conducted on 15 participants who were exposed to 8 different colour and intensity light conditions. The participants' HR and SC were recorded under each colour and intensity light, and they were asked to complete SAM. The research demonstrates that there is a change in HR, SC, arousal and valence of participants due to change in the colour and intensity of lights. However, the direction of change was subject dependent, where the same colour and intensity light can have different effects on people. The research suggests that architects and designers of any space must take into account the individual differences of the predicted users when designing the lights and colours. It is also seen from the results that some colour and intensity lights have greater impact on the emotions of participants than others. Although it is not possible to correlate the colour and lighting conditions to a specific effect on all participants, general effects for some colour lights were drawn from the results. It is well documented in literature that HR and SC are a good measure of emotion. However the results of this study show very high inter subject variation in HR and SC. This is due to people having different HR and SC in normal conditions. This research demonstrates that the use of HR and SC to measure the effect of a stimulus on a group of people is unreliable because it is hard to compare the results.

The objective of this project is to develop a device that can monitor the heart rate and respiration of cetaceans. This would provide a way to quantitatively measure stress and determine the impact of human activity on cetaceans, especially for certain species that have been difficult to monitor in the past. There are many challenges to developing such a device, including determining the appropriate type of sensor, reducing the effect of flow noise, and designing an effective attachment method; this paper primarily focuses on determining the most suitable acoustic transducer. Experiments were conducted to compare various acoustic sensors in detecting heart rate. The electronic stethoscope performed the best in the experiments, but the results showed that other transducers, such as accelerometers and pressure sensors, also performed well and could be successful options with further development. Data processing methods to identify heartbeats and characterize signals are also discussed in this paper. Future work on the project involves subsequent tests to address other design variables as well as replicate experiments on animals.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.

Context: Sudden Infant Death Syndrome (SIDS) is a phenomenon in which new-born-infants die, often during sleeping, and no cause of death is identified after the autopsy and examination. Assumptions can be made in order to understand what happened to the infant, e.g. heart failures and insufficient breathing rate due to the position of the infant, although deeper studies are hard to be performed, since recording real-cases of sudden infant death on camera is not so trivial. Objectives: Our main objective with the work hereby presented is to perform a study on practical issues that may arise when one is contemplating to build a mobile application for monitoring the heart rate of individuals. These issues may include the levels of accuracy of heart rate measurements that can be retrieved by the current technology, best room conditions for the application to work and positioning of the device in respect to the subject under monitoring. Our secondary objective with this work is to present a heart rate monitor prototype application at a conceptual level. Methods: We conducted a literature review and an analysis of the current available technology, approaches and applications for smart-phones. We conducted experiments on a controlled environment by taking heart rate measurements and comparing results obtained from one smart phone application with results obtained with one standard electrocardiogram tool. After gathering the outputs of the experiments, we analyzed the patterns with the ultimate goal to identify the best set of parameters for the application to work. Results: Our main achievements were obtained through the data that we collected. Although related this work with SIDS, we collected data from adults. The procedures for obtaining the Heart Rate with the application analyze the skin of an individual and, thus, it does not matter if it is an infant or adult. We identified relevant parameters that affect directly the performance of the application, leading it to malfunction. Finally, we proposed a prototype of a mobile heart rate monitoring, that we named The Mobile Heart Rate Monitoring System (MHRMS) at a conceptual level, adding-up functionality to the existing technology and also outlining the best conditions and positioning for it to work correctly. Conclusions: The main conclusion that we reached is that it is reasonable to make use of the current technology that are available in today’s smart phones for having a trustworthy heart rate monitoring tool.

Abstract Heart rate variability (HRV) is used in the assessment of cardiovascular health. However, often contradictory results have impeded the efficient use of HRV in clinical practice. HRV signals can contain artifacts leading to errors in the interpretation of HRV results. Various methods have been used for artifact editing, but there is relatively little information on how the actual editing can influence the HRV measures. The main aim of this thesis was to improve the reliability of HRV analysis by concentrating on the HRV signal preprocessing methods. The effects of three editing methods on the HRV of short (512 R-R) and long-term (24-hour) R-R interval data were studied with non-edited and edited data from healthy subjects (n=10) and patients with acute myocardial infarction (AMI) (n=10). The effects of ectopic beats on short (α1) and long-term (α2) fractal scaling exponents were studied by inserting artificial ectopic beats into the HRV signals of 20 healthy subjects and 20 AMI patients. The prognostic significance of edited and non-edited α1 and α2 was studied in random elderly (n=84) and post-AMI (n=84) populations. A new method to quantify respiratory sinus arrhythmia (RSA) was developed based on the HRV signals of 13 healthy subjects. A new measure, the RSA index, was defined to evaluate the risk to sudden cardiac death (SCD) in 1631 AMI patients. Lastly, a new algorithm was developed in order to edit heart rate (HR) turbulence occurring immediately after a ventricular premature beat (VPB). The effects of HR turbulence editing on the HRV analysis were studied in 267 AMI patients. Editing had distinct effects on the HRV analysis depending on the editing method and data type. Deletion editing was found to be unsuitable for the HRV spectrum analysis. There was no universal editing method for the time and frequency domain HRV analyses. Unedited ectopic beats increased the randomness of short-term R-R interval dynamics, especially in AMI patients. However, unedited α1 differed significantly between survivors and those who died during the follow-up. Ectopic beats do not necessarily need to be edited if fractal analysis is used in the risk evaluation. A depressed RSA index was found to be a strong predictor of SCD but a weak predictor of non-SCD in AMI patients. Editing of HR turbulence affected differently the various HRV measures. ULF and VLF components were most clearly influenced by HR turbulence removal. The amount of VBPs had an important impact on the results. When the VBPs/hour were >50, ULF and VLF were >30% lower after turbulence removal. The results of this thesis highlight the importance of editing the erroneous or irrelevant R-R interval oscillation in an HRV analysis. The careful choice of preprocessing method is essential if one wishes to obtain reliable HRV analyses for clinical purposes.

Magister Curationis - MCur / The objectives of this study were to determine midwives’ knowledge in performing foetal heart rate monitoring, to assess midwives’ abilities in the interpretation of foetal heart rate patterns according to their years of clinical experience as a registered midwife.

Title Repeated individual comparasion of heart rate on the land and in the water. Objective Find if exist significant difference of heart rate in repeated measurements between rating heart rate on dry land and in the water. Used methods The quantitative empirical research was carried out. The research method was the measurement of resting heart rate. Measurements were carried out in the form of intraindividual comparative analysis among six probands who were repeatedly tested supine for 5 minutes on land and subsequently 5 minutes in water. The water temperature was 30 řC and the water column height was 30 cm. Heart rate was measured using sporttester. Results The same tendency of reaction of the organism during repeated measurements did not confirm in 4 cases. Results in two cases confirmed the trend of decreasing heart rate during a stay in the water. The most measured resting heart rate decreased in water compared with the resting heart rate on dry land by 21.1% and increased the most by 6.1%. Keywords swimming, water, heart rate, resting heart rate, diving