10 research outputs found

    Recovery of heart rate variability after treadmill exercise analyzed by lagged Poincaré plot and spectral characteristics

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    © 2017 International Federation for Medical and Biological Engineering The aim of this study was to analyze the recovery of heart rate variability (HRV) after treadmill exercise and to investigate the autonomic nervous system response after exercise. Frequency domain indices, i.e., LF(ms 2 ), HF(ms 2 ), LF(n.u.), HF(n.u.) and LF/HF, and lagged Poincaré plot width (SD1 m ) and length (SD2 m ) were introduced for comparison between the baseline period (Pre-E) before treadmill running and two periods after treadmill running (Post-E1 and Post-E2). The correlations between lagged Poincaré plot indices and frequency domain indices were applied to reveal the long-range correlation between linear and nonlinear indices during the recovery of HRV. The results suggested entirely attenuated autonomic nervous activity to the heart following the treadmill exercise. After the treadmill running, the sympathetic nerves achieved dominance and the parasympathetic activity was suppressed, which lasted for more than 4 min. The correlation coefficients between lagged Poincaré plot indices and spectral power indices could separate not only Pre-E and two sessions after the treadmill running, but also the two sessions in recovery periods, i.e., Post-E1 and Post-E2. Lagged Poincaré plot as an innovative nonlinear method showed a better performance over linear frequency domain analysis and conventional nonlinear Poincaré plot

    Poincaré Plot analysis and Graphical User Interface development for the study of Heart Rate Variability in asthmatic children

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    Asthma is a chronic lung disease that inflames and narrows the airways, and although it affects people of all ages it most often starts during childhood. However, there is still not a clinical method for the premature diagnosis of asthma, what makes it dependent on the doctor criteria. Some studies have shown that the pathophysiology of asthma is related with an abnormal ANS function that is responsible of bronchoconstriction. As ANS activity is reflected in HRV, the analysis of this HRV could lead to an interpretation of the physiologic processes underlying asthma, thus serving as a non-invasive way to diagnose it. It is nowadays agree that the several processes involved in HR control interact in a non-linear way and so non-linear analysis of HRV has received high research interest in the last years, so in this work the focus is on Poincaré plot analysis, which is one of the most representative non-linear HRV analysis techniques. Poincaré plot is a quantitative-visual technique extracted from non-linear dynamics, although the indexes extracted from it have been proven to not provide additional information to that obtained with other methods. Due to this fact, in this work a research in the origins of Poincaré plot has been attempted, in order to define new parameters that can display the non-linear characteristics of the plot. The angle of the plot and the short-term analysis of its shape were proposed, being the objective to find an index that can be used to classify a set of patients aged 3-7 years attending to their risk of suffering from asthma. Furthermore, a GUI was developed so that the information provided by Poincaré plots can be easily compared and integrated with the information extracted from several other indexes. Although the methods proposed for the extraction of the angle and the shape information were successful, the results obtained in this work showed that the use of both the classical HRV indexes and the new proposed parameters is not enough to stratify the risk of asthma in children. However, the GUI developed was shown to result useful when interpreting Poincaré plot information. Also a qualitative analysis of a Poincaré domain filtering technique proposed in the literature was performed, and several future work lines were established

    Examination of cardio-respiratory coupling preservation and its predictive role in response to resynchronization therapy in patients with heart failure

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    njihove promene izazvane resinhronizacionom terapijom kod bolesnika sa srčanom slabošću (SS) i redukovanom ejekcionom frakcijom leve komore (EFLK). Metode: U istraživanje su uključeni bolesnici sa dilatativnom kardiomiopatijom i indikacijom za resinhronizacionu terapiju srčane slabosti (CRT) i/ili ugradnju implantabilnog kardioverter defibrilatora. Ispitanici su tokom istraživanja bili deljeni u podgrupe u odnosu na karakteristike srčanog ritma, a poređenje je vršeno sa grupom zdravih kontrola. Srčani i respiratorni signali su simultano beleženi tokom 20 minuta, i ispitivani različitim linerarnim i nelinearnim metodama analize vremenskih serija. Kod ispitanika kojima je ugrađen CRT, snimanje signala je ponovljeno nakon godinu dana i analiza promene parametara autonomne funkcije je odvojeno rađena u grupi CRT „rispondera“ i „nerispondera“. Rezultati: U istraživanje je uključeno 156 ispitanika. Kod bolesnika sa SS redukovana je respiratorna sinusna aritmija, kao i bidirekciona interakcija srčanog i respiratornog signala. Bolesnici iz HF-VES grupe su imali najregularniji srčani ritam i najveću sinhronizaciju rada srca i disanja. Identifikovali smo odnos kratkodometnog, α1(RR), i dugodometnog, α2(RR), skalirajućeg eksponenta vremenskog niza RR intervala kao parametar na osnovu kojeg je moguće grupisanje bolesnika sa SS nezavisno od do sada korišćenih karakterisitka bolesnika. Parametar koji je preoperativno odvojio buduće CRT „rispondere“ od „nerispondera“ bio je α2(RR). Tokom praćenja, kompleksnost srčanog i respiratornog ritma je rasla kod CRT „rispondera“, kao i α1(RR) koji je na kontrolnom snimanju imao značajno više vrednosti u odnosu na „nerispondere“. Na kontroli se beleži porast respiratornih skalirajućih eksponenata kod svih bolesnika, sa izuzetkom α1(Resp) kod CRT „nerispondera“. Tokom praćenja, kardiopulmonalna sinhronizacija je bila očuvana kod CRT „rispondera“. Zaključak: kardio-respiratorne interakcije su narušene kod bolesnika sa SS i redukovanom EFLK, i zavise od prisustva komorskih odnosno pretkomorskih aritmija. Uspeh resinhronizacione terapije je značajno povezan sa njihovom stabilnošćuAim: Examine cardio-respiratory interactions, cardiac and respiratory rhythm, and their changes caused by cardiac resynchronization therapy (CRT) in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF). Methods: We included patients with dilated cardiomyopathy and an indication for CRT and/or implantable cardioverter defibrillator implantation. During the study, patients were divided into subgroups according to heart rhythm characteristics, and compared with a group of healthy controls. Cardiac and respiratory signals were simultaneously recorded during 20 minutes, and examined by different linear and nonlinear methods of time series analysis. In subjects with implanted CRT, signal recording was repeated after one year, and the analysis of changes in autonomic function parameters was performed separately in the group of CRT responders and non-responders. Results: We included 156 patients. In HF patients, respiratory sinus arrhythmia and bidirectional causal interactions between the respiratory and cardiac signals were reduced. Patients from the HF-VES group had the most regular heart rhythm and the greatest synchronization of cardiac and respiratory function. We identified the ratio of short-term, α1(RR), and long-term, α2(RR), scaling exponent of RR interval series as a parameter capable to differentiate HF patients regardless of previously used patient characteristics. The parameter that preoperatively separated future CRT "responders" from "non-responders" was α2(RR). During follow-up, the complexity of cardiac and respiratory rhythm increased in CRT responders, as well as α1(RR), which had significantly higher values at the control recording compared to non-responders. Control measurements showed an increase in respiratory scaling exponents in all patients, with the exception of α1(Resp) in CRT non-responders. During follow-up, cardiopulmonary synchronization was preserved in CRT responders. Conclusion: Cardio-respiratory coupling is altered in HF patients with reduced LVEF and depends on the presence of atrial and ventricular arrhythmias. CRT success is related to cardio-respiratory coupling stability

    Análisis lineal y no lineal de la dinámica de la regulación autonómica de los sistemas cardiovascular y respiratorio durante la prueba ortostática

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    En la presente tesis doctoral en Ciencias en Ingeniería Biomédica se investigó la regulación autonómica durante el reto ortostático con un enfoque en el análisis de su dinámica temporal utilizando segmentos de corto plazo de las series de tiempo cardiovasculares y respiratorias. Los sujetos enrolados en el estudio incluyeron 12 hombres y 12 mujeres sanos jóvenes, así como 16 mujeres con diagnóstico de síncope vasovagal, con edad similar. La investigación tuvo un doble objetivo: primero, estudiar el efecto de género en personas sanas y segundo, evaluar en mujeres el efecto del síncope vasovagal, sobre la regulación autonómica de los sistemas cardiovascular y respiratorio utilizando un reto ortostático. Además de incluir el análisis de variables hemodinámicas, se analizaron la variabilidad de los intervalos entre latido y latido, de las señales respiratorias, así como de la presión arterial sistólica y diastólica. Las series de tiempo se adquirieron durante la prueba de inclinación a 70°. Las series de tiempo se analizaron mediante técnicas de procesamiento univariadas y bivariadas que proporcionaron información de la variabilidad, la complejidad, el acoplamiento y las interacciones presentes durante la progresión del reto ortostático. La extracción de características se llevó a cabo usando diversos métodos lineales y no lineales en los dominios del tiempo, frecuencia e información. Las técnicas lineales incluyen las recomendadas por Task Force como la función de correlación, el método de doble secuencia y la función de coherencia dirigida parcial. Los métodos no lineales involucraron la dinámica simbólica, la compresión por entropía, análisis de fluctuación sin tendencia, análisis de la irreversibilidad con respecto al tiempo, información mutua, así como diferentes enfoques basados en la entropía en múltiples escalas de tiempo, análisis de la representación de Poincaré y la dinámica simbólica conjunta. En cuanto a los resultados, los valores medios de las variables hemodinámicas no arrojaron diferencias estadísticas entre grupos. Con respecto al efecto del género en los controles, en hombres se obtuvieron diferencias estadísticas durante la línea de base (posición supina) incluyendo una mayor presión arterial sistólica, una menor variabilidad y complejidad de la frecuencia cardíaca, así como un acoplamiento cardiorrespiratorio reducido. Durante la progresión de la fase ortostática, las diferencias de género siguieron o fueron más pronunciadas, especialmente con relación a la variabilidad de la frecuencia cardíaca. Además, la frecuencia respiratoria también aumentó significativamente durante la fase ortostática. Del mismo modo, en hombres el acoplamiento cardiovascular y cardiorrespiratorio disminuyó durante la fase ortostática.En general, los resultados indicaron que en los controles masculinos existió un incremento de la actividad simpática, inmediatamente después de la inclinación, y que se mantuvo durante la fase ortostática. Por el contrario en las mujeres sanas, la regulación autonómica se caracterizó por un equilibrio simpático-vagal pronunciado durante el reto ortostático seguido por un ligero aumento, pero retrasado, de la actividad simpática al final de la fase ortostática. En consecuencia, los análisis mostraron que en estudios de reto ortostático los hombres y las mujeres deben investigarse por separado debido a las diferentes respuestas temporales autonómicas. Con respecto al efecto de síncope vasovagal en las mujeres, casi todas las técnicas aplicadas demostraron diversas diferencias estadísticamente significativas, durante varios minutos e incluso en toda la fase ortostática. Varios de los métodos mostraron diferencias considerables dentro de los primeros minutos después de inclinar al sujeto, donde aún no existían síntomas de presíncope. Las diferencias distintivas durante la fase ortostática incluyeron un aumento de la frecuencia respiratoria, una disminución de la variabilidad y complejidad de la frecuencia cardiaca, un aumento de la variabilidad y complejidad respiratoria, un aumento de la variabilidad y complejidad de la presión arterial sistólica así como una disminución y/o alteración de los acoplamientos e interacciones cardiovasculares y cardiorrespiratorias en pacientes femeninas. Los resultados claramente señalaron un aumento sostenido de la actividad simpática que afectó la regulación autonómica del sistema cardiovascular y respiratorio debido al reto ortostático en pacientes femeninas jóvenes y susceptibles al síncope vasovagal. Los resultados mostraron la ventaja de realizar una descripción temporal detallada de la regulación autonómica durante el reto ortostático que depende del género y de la susceptibilidad al síncope vasovagal. Además, durante la investigación doctoral se formularon y evaluaron procedimientos alternativos para analizar la dinámica temporal de las series de tiempo cardiovasculares y respiratorias. Se propusieron nuevos procedimientos que combinan la entropía multiescala y la dinámica simbólica, y se establecieron sugerencias para el análisis segmentado de Poincaré. Asimismo, se propusieron nuevos parámetros para la dinámica simbólica a corto plazo y la entropía multiescala. Adicionalmente, se introdujo un nuevo método no lineal para estudiar acoplamientos e interacciones, llamado el análisis gráfico en el espacio delta. Estos índices y métodos revelaron resultados prometedores que deben de investigarse en mayor medida en futuros estudios

    From Ecological Epitome to Medical Model: An investigation into Applications for the use of Daphnia in Heart Science.

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    The primary aim of this research was to determine whether Daphnia might become a model for cardiovascular concentration-response trials. This would provide a high throughput means of testing cardiac therapeutics without resort to small mammal trials. We found Daphnia are inappropriate in this context due to high population variance and sensitivity to small, subtle, environmental changes. A new aim was developed to determine whether beat-to-beat variation could be correlated with an individual’s response to toxic insult. Further, to develop more accurate and efficient means of gathering heart rhythm data by recording heart movement from whole live Daphnia. This opens the way to individualising cardio therapeutics; by correlating the stability of individual hearts with response to cardiac insult, regression analysis provides a means of finding a prediction tool. Daphnia are a convenient example here, but successful scoring systems might also be applied to the human heart via analysis of ECG readouts. Collecting signals from whole live Daphnia did not fulfil the goal of gathering heart data as this instead recorded limb movement. However, this provides a means of improving toxicology testing in aquatic ecology. This thesis offers three contributions to knowledge: 1. Daphnia are an inappropriate model for cardiovascular therapeutic dose-response trials due to extreme environmental sensitivities. 2. Baseline heart rhythm can be correlated with paired response to cardiac insult, with significance at the 0.01 alpha level, using an adjusted version of the Lyapnov equation; Finite Time Growth (Wessel, 2010). However, this is only if population variation is adequate. It is better applied to a natural in situ population than a homegenic lab population. 3. A novel technique for measuring Daphnia electromechanical movement records feeding limbs rather than the heart. This offers a novel and more efficient technique for aquatic ecotoxicology, where visual observation or films of the same are currently used

    A Systematic Review and Meta-Analysis of the Incidence of Injury in Professional Female Soccer

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    The epidemiology of injury in male professional football is well documented and has been used as a basis to monitor injury trends and implement injury prevention strategies. There are no systematic reviews that have investigated injury incidence in women’s professional football. Therefore, the extent of injury burden in women’s professional football remains unknown. PURPOSE: The primary aim of this study was to calculate an overall incidence rate of injury in senior female professional soccer. The secondary aims were to provide an incidence rate for training and match play. METHODS: PubMed, Discover, EBSCO, Embase and ScienceDirect electronic databases were searched from inception to September 2018. Two reviewers independently assessed study quality using the Strengthening the Reporting of Observational Studies in Epidemiology statement using a 22-item STROBE checklist. Seven prospective studies (n=1137 professional players) were combined in a pooled analysis of injury incidence using a mixed effects model. Heterogeneity was evaluated using the Cochrane Q statistic and I2. RESULTS: The epidemiological incidence proportion over one season was 0.62 (95% CI 0.59 - 0.64). Mean total incidence of injury was 3.15 (95% CI 1.54 - 4.75) injuries per 1000 hours. The mean incidence of injury during match play was 10.72 (95% CI 9.11 - 12.33) and during training was 2.21 (95% CI 0.96 - 3.45). Data analysis found a significant level of heterogeneity (total Incidence, X2 = 16.57 P < 0.05; I2 = 63.8%) and during subsequent sub group analyses in those studies reviewed (match incidence, X2 = 76.4 (d.f. = 7), P <0.05; I2 = 90.8%, training incidence, X2 = 16.97 (d.f. = 7), P < 0.05; I2 = 58.8%). Appraisal of the study methodologies revealed inconsistency in the use of injury terminology, data collection procedures and calculation of exposure by researchers. Such inconsistencies likely contribute to the large variance in the incidence and prevalence of injury reported. CONCLUSIONS: The estimated risk of sustaining at least one injury over one football season is 62%. Continued reporting of heterogeneous results in population samples limits meaningful comparison of studies. Standardising the criteria used to attribute injury and activity coupled with more accurate methods of calculating exposure will overcome such limitations
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