The Hilbert transform is a widely used transform in signal processing. In this thesis we explore its use for three different applications: electrocardiography, the Hilbert-Huang transform and modulation. For electrocardiography, we examine how and why the Hilbert transform can be used for QRS complex detection. Also, what are the advantages and limitations of this method? The Hilbert-Huang transform is a very popular method for spectral analysis for nonlinear and/or nonstationary processes. We examine its connection with the Hilbert transform and show limitations of the method. Lastly, the connection between the Hilbert transform and single-sideband modulation is investigated.

Sudden cardiac death (SCD) in a young person is a rare but tragic event, and the potential of prevention is unknown. The aim of this thesis is to contribute to the prevention by analysing SCD in the young in Sweden during the period 1992-1999. Data of SCD in the young based on a national registry is not previously reported. The approach is broad, covering the spectrum from epidemiology to supportive needs of families confronted with SCD. The survey methods comprised analyses of national registries, questionnaires, personal interviews, forensic-, police-, medical- and military conscription records. The SCD group selected from the database of the National Board of forensic Medicine consisted of 181 persons, 15 to 35 years old, who had suffered an SCD during 1992-1999 in Sweden, 132 men (73 %) and 49 women (27 %). The mean incidence was 0.93 per 100,000 per year. The trend showed no decrease during the surveyed years, 1992-1999. The most common diagnoses were the structurally normal heart (21 %), coronary artery disease (18 %), and dilated cardiomyopathy (12 %). In a study group of 162 individuals (19 cases of aortic aneurysm, 17 men and two women, were excluded), ECGs, symptoms and lifestyle factors were analysed and related to the autopsy findings. ECGs were available in 66 individuals (59 men and seven women) and 50 % of these were pathological. The most frequent aberrations were repolarisation abnormalities and in half of the cases with more than one ECG a development in a pathological direction was seen. In four out of ten seeking medical advice because of symptoms an ECG was taken and three of these were pathological. Possibly cardiac-related alpitations were common, but also non-specific symptoms such as fatigue after an influenza- like illness. It was not possible to link a certain sign or symptom to a specific diagnosis. In 26 (16 %) there was a family history of SCD. Physical activity and body mass index (BMI) in men were the same as in a control group, whilst women had a higher BMI and a lower level of physical activity than the controls. In coronary artery disease deaths there were a high percentage of smokers and BMI was higher than in the controls in both sexes. Competing athletes more often died during physical activity than non-athletes, but were not overrepresented in the SCD group. The majority of the athletes who died during physical activity had an underlying structural cardiac disease. Death during sleep was the most common mode of death in subjects with structurally normal heart. A lack of supportive structures in the handling of bereaved relatives were disclosed in the interviews. Most participants felt that they had been left mainly to themselves to find information and support. A common reflection from the bereaved was that there is a need of the same supportive routines in cases of a single death as in accidents where there are several casualties. The bereaved had a need of getting an explanation and a need of supportive structures. The cognitive dimension of understanding and the emotional dimension of being understood were found to be significant for the complex processes of mourning and recreating one’s life as a bereaved. In summary, SCD was uncommon in the young, but the incidence was not decreasing during the study period. The most common autopsy findings were the structurally normal heart and coronary artery disease. Symptoms preceding SCD were common but often misinterpreted. The SCD group was very similar to the normal population with regard to life style factors. In certain cardiac disorders physical activity seemed to trigger sudden death, whilst in others death during sleep was the most common mode of death. There is no single test which predicts if a person is at risk of SCD. A further cardiac evaluation in cases with pathological ECGs, and in cases with a positive family history or serious unexplained symptoms such as syncope, might permit the early identification of persons at risk of SCD. ECG is an underused tool in the investigation of symptoms, and a database with old ECGs available for comparison could be useful in the prevention of SCD. There is a need of better care of the bereaved, and based on our findings we propose the introduction of a supportive program.

Η διπλωματική εργασία με τίτλο «Μέθοδοι για Ανίχνευση και Χαρακτηρισμό Βιοσημάτων σε Θορυβώδεις Χρονοσειρές βασισμένοι στο Μετασχηματισμό Hilbert-Huang» μελετάει ζητήματα που σχετίζονται με βιοϊατρικά σήματα και την ανάλυση τους. Γίνεται διερεύνηση των διαθέσιμων τεχνικών και μεθόδων ανάλυσης βιοϊατρικών σημάτων, επισημαίνονται τα ιδιαίτερα χαρακτηριστικά των χρονοσειρών που προκύπτουν από την παρατήρηση και καταγραφή των σημάτων και έμφαση δίνεται στη μη στασιμότητα, την μη γραμμικότητα των υποκείμενων φυσικών διεργασιών και την ανάγκη προσαρμοστικότητας της μεθόδου. Μια μέθοδος που ικανοποιεί αυτές τις απαιτήσεις είναι η εμπειρική μέθοδος αποσύνθεσης η οποία αναλύει ένα σήμα σε ένα σύνολο συνιστωσών (IMFs) από τις οποίες ένα υποσύνολο θεωρείται ότι έχει φυσική σημασία. Επιπλέον, με το μετασχηματισμό Hilbert ανιχνεύονται οι στιγμιαίες συχνότητες και διαμορφώνεται η χρονοσυχνοτική κατανομή του σήματος. Τα θέματα που διερευνώνται αναφορικά με την εμπειρική μέθοδο αποσύνθεσης αφορούν τη στατιστική σημαντικότητα των IMFs, την αποθορυβοποίηση βιοϊατρικών σημάτων, την εξαγωγή χαρακτηριστικών από ηλεκτροκαρδιογράφημα και την απόδοση της μεθόδου. Ειδικά η απόδοση της εμπειρικής μεθόδου αποσύνθεσης είναι κρίσιμη παράμετρος για συστήματα με περιορισμένους πόρους όπως είναι οι κόμβοι ασύρματων δικτύων αισθητήρων ή τα ενσωματωμένα συστήματα. Η μοντελοποίηση μεθόδων που υλοποιούνται στο επίπεδο κόμβων ασύρματου δικτύου αισθητήρων είναι απαραίτητη για τη βέλτιστη διαχείριση πόρων και τον προγραμματισμό διεργασιών ώστε να μην διαταραχθεί η λειτουργία και λειτουργικότητα του συστήματος / This diploma thesis entitled "Methods for Identification and Characterization of Biosignals in Noise corrupted Time Series based on Hilbert-Huang Transform " studies issues concerning biomedical signal analysis. There is a review of the available techniques and methods for biomedical signal analysis pointing at certain characteristics of biomedical time series such as non stationarity, the non linearity of the underlying physical process and the need for the adaptive nature of the analysis method. One method that meets these requirements is considered to be the Empirical Mode Decomposition (EMD) which decomposes a signal into a set of components (IMFs) that a subset of them is believed to have a physical meaning. Application of Hilbert Transform on these IMFs provides the instantaneous frequencies and forms the time-frequency distribution of the signal. Issues studied are related to the statistical significance of the IMFs, denoising of biomedical signals, characteristics extraction and feature selection out of the electrocardiogram as well as the performance of the method. Particularly, the performance of empirical mode decomposition is considered to be a critical parameter especially in the case of implementation on nodes of wireless sensor networks or generally embedded systems due to the limited amount of resources available onboard. Modeling method's performance and demand for resources is a significant task facilitating the optimum resource management and task execution schedule of these systems.

Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-04-13T17:44:56Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wallinson_oliveira_schutte.pdf: 2955879 bytes, checksum: 7d21ec1707fa5cf82b0b96642d27fa03 (MD5) / Rejected by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br), reason: Verificar refer?ncia e keywords. on 2018-04-20T15:00:26Z (GMT) / Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-05-15T18:16:15Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wallinson_oliveira_schutte.pdf: 2955879 bytes, checksum: 7d21ec1707fa5cf82b0b96642d27fa03 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-05-15T19:38:43Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wallinson_oliveira_schutte.pdf: 2955879 bytes, checksum: 7d21ec1707fa5cf82b0b96642d27fa03 (MD5) / Made available in DSpace on 2018-05-15T19:38:43Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wallinson_oliveira_schutte.pdf: 2955879 bytes, checksum: 7d21ec1707fa5cf82b0b96642d27fa03 (MD5) Previous issue date: 2017 / O presente estudo prop?e o desenvolvimento de duas ferramentas para se fazer a classifica??o de batimentos card?acos a fim de detectar a Isquemia Card?aca. Uma baseada em propriedades da Distribui??o Normal e Teorema de Bayes e a outra baseada em Redes Neurais Artificiais. Utilizando o banco de dados Long-Term ST Database, foi efetuado um filtro de dados, que foram agrupados pelas seguintes deriva??es: A-S, E-S, A-I, ML2, MV2, ML3, V4 e V5. Por meio dos algoritmos propostos, implementados por interm?dio da Linguagem de Programa??o PHP, p?de-se verificar a deriva??o mais prop?cia a se detectar essa doen?a. Foi poss?vel observar as deriva??es V5 e A-S com melhores resultados utilizando-se o algoritmo h?brido. Na V5, foi obtido Sensibilidade de 100%, Especificidade de 97%, Valor Preditivo Positivo de 95.89% e Valor Preditivo Negativo de 100% e, na A-S, valores de 99.22%, 99.99%, 99.99% e 99.61% para Sensibilidade, Especificidade, Valor Preditivo Positivo e Valor Preditivo Negativo. O algoritmo de Redes Neurais Artificiais apresentou o melhor resultado para deriva??o A-S com 99.98%, 100%, 100% e 99.99% para Sensibilidade, Especificidade, Valor Preditivo Positivo e Valor Preditivo Negativo respectivamente. Tamb?m foi calculado o intervalo de confian?a para propor??es populacionais com 95% de confian?a, a fim de se estabelecer n?veis de precis?o das bases utilizadas. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Tecnologia, Sa?de e Sociedade, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The present study proposes the development of two tools to classify heart beats in order to detect cardiac ischemia. One based on properties of Normal Distribution and Bayes' Theorem and the other based on Artificial Neural Networks. Using the Long-Term ST Database, a data filter was performed, which was grouped by the following derivations: A-S, E-S, A-I, ML2, MV2, ML3 and V4, V5. By means of the algorithms proposed, implemented through the PHP Programming Language, we could verify the most favorable derivation to detect this disease. It was possible to observe the V5 and A-S leads with better results using the hybrid algorithm. In V5, 100% sensitivity, 97% specificity, 95.89% positive predictive value and 100% negative predictive value were obtained, and in A-S, values of 99.22%, 99.99%, 99.99% and 99.61% for sensitivity, specificity, positive predictive value, and negative predictive value. The algorithm of Artificial Neural Networks presented the best result for A-S derivation with 99.98%, 100%, 100% and 99.99% for sensitivity, specificity, positive predictive value and negative predictive value respectively. We also calculated the confidence interval for population proportions with 95% confidence in order to establish precision levels of the bases used. / El presente estudio propone el desarrollo de dos herramientas para la clasificaci?n de los latidos del coraz?n con el fin de detectar la isquemia card?aca. Uno basado en las propiedades de la Distribuci?n Normal y el Teorema de Bayes y el otro basado en las Redes Neuronales Artificiales. Utilizando la base de datos Long-Term ST Database, se llev? a cabo un filtro de datos, que fueron agrupados seg?n las siguientes derivaciones: a-S, E, S, A-I, ML2, MV2, ML3, V4 y V5. Por medio de los algoritmos propuestos, implementado a trav?s del lenguaje de programaci?n PHP, pudimos comprobar la derivaci?n m?s favorable para detectar esta enfermedad. Fue posible observar las derivaciones V5 y A-S con mejores resultados utilizando el algoritmo h?brido. En V5 se obtuvo una sensibilidad del 100%, uma especificidad del 97%, 95.89% de valor predictivo positivo y 100% de valor predictivo negativo y en A-S, valores de 99.22%, 99.99%, 99.99% y 99.61% para la sensibilidad, especificidad, valor predictivo positivo, y valor predictivo negativo respectivamente. El algoritmo de Redes Neuronales Artificiales present? el mejor resultado para la derivaci?n A-S con 99.98%, 100%, 100% y 99.99% para la sensibilidad, especificidad, valor predictivo positivo y valor predictivo negativo, respectivamente. Tambi?n fue calculado el intervalo de confianza para proporciones de las poblaciones con 95% de confianza con el fin de establecer los niveles de confianza precisi?n de las bases utilizadas

Made available in DSpace on 2016-06-02T19:22:07Z (GMT). No. of bitstreams: 1 4026.pdf: 5869233 bytes, checksum: 564f050b40a7e6caef2306f78b3a44da (MD5) Previous issue date: 2011-12-21 / Financiadora de Estudos e Projetos / Aquatic environments are subjected to wide variations in their physicochemical properties which can compromise the survival of the animals that inhabit these waters, especially the fish, which exhibit adaptive behavioral, physiological, biochemical and genetic responses to face such variations. The aim of the present study was to assess the relationship between heart morphology and the cardiorespiratory responses to hypoxia at different temperatures (15, 25 and 35 °C) of two fish species with different habits and habitats: matrinxã (Brycon amazonicus) and trahira (Hoplias malabaricus). Both species presented pyramidal ventricles with compact and spongy layers (mixed myocardium), differentiated by the thickness of the compact layer and its irrigation, which occurs in greater proportion in matrinxã, the active species. Gradual temperature reductions decreased the values of metabolic rate ( ̇ ), gill ventilation ( ̇ ), respiratory frequency (fR), ventilatory volume (VT), and heart rate (fH) while increases in temperature induced opposite responses, increasing the values of these parameters. In matrinxã and trahira, the gradual reduction in the water O2 concentration at different temperatures induced significant changes in the cardiorespiratory parameters. The combined effects of low temperature (15 °C) and hypoxia led to a significant reduction in ̇ , ̇ , fR, VT, EO2 (O2 extraction) and fH, while high temperature (35 °C) and hypoxia led to a significant increase in these parameters. The results showed that temperature acts in the overall metabolism of fish as well as in myocardial metabolism and membrane permeability to the ions involved in their polarity. Moreover, the active species matrinxã presented higher values of cardiorespiratory parameters and a lower tolerance to hypoxia when compared to trahira, the sedentary species. / Os ambientes aquáticos estão sujeitos a grandes variações em suas propriedades físicoquímicas as quais pode comprometer a sobrevivência dos animais que habitam essas águas, especialmente os peixes, os quais exibem comportamento adaptativo, respostas fisiológicas, bioquímicas e genéticas para enfrentar tais mudanças. O objetivo do presente estudo foi avaliar a relação entre a morfologia cardíaca e as respostas cardiorrespiratórias à hipóxia e em diferentes temperaturas (15, 25 e 35 °C) em duas espécies de peixes de diferentes hábitos e habitats: matrinxã (Brycon amazonicus) e traíra (Hoplias malabaricus). Ambas as espécies possuem ventrículos piramidais, com camada compacta e esponjosa (miocárdio misto), diferenciadas pela espessura da camada compacta e sua irrigação, a qual ocorre em maior proporção em matrinxã, espécie ativa. A redução gradual da temperatura diminuiu os valores da taxa metabólica ( ̇ ), ventilação branquial ( ̇ ), frequência respiratória (fR), volume ventilatório (VT) e frequência cardíaca (fH), enquanto o aumento da temperatura levou a respostas opostas, aumentando os valores destes parâmetros. Tanto no matrinxã, quanto na traíra, a redução gradual na concentração O2 da água em diferentes temperaturas induziram alterações significativas nos parâmetros cardiorrespiratórios. Os efeitos combinados da baixa temperatura e hipóxia levaram a uma redução significativa na ̇ , na ̇ , na fR, no VT, na EO2 (extração de O2) e na fH, enquanto altas temperaturas (35 °C) e hipóxia levaram a um aumento destes parâmetros. Os resultados sugerem que a temperatura atue no metabolismo global do peixe, bem como no metabolismo do miocárdio e na permeabilidade de membrana aos íons envolvidos em sua polaridade. Além disso, o matrinxã, espécie ativa, apresentou valores mais elevados dos parâmetros cardiorrespiratórios e uma menor tolerância à hipóxia, quando comparada com traíra, espécie de hábito sedentário.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Quercetin is a flavonoid widely distributed in plants, and it is shown to have several biological activities. This study aims to describe the effects of quercetin on the contracting and electrophysiological properties of the cardiac muscle as well as the homeostasis of intracellular calcium. This study evaluated the inotropic effect of quercetin in guinea pigs’ left atria, its effects on the adrenergic receptors, and on the electrocardiographic parameters. In mice ventricular cardiomyocytes the L-type Ca2+ current (ICa,L), the intracellular Ca2+ global transient and the calcium sparks were evaluated. The results revealed a positive inotropic effect from quercetin (EC50 3.64 x 10-6 M, n = 4) that was significantly reduced by 1 M propranolol. Furthermore, quercetin caused diastolic relaxation (~7%). In ventricular cardiomyocytes, 30 μM quercetin increased the density of ICa,L at 0 mV of −0.95 ± 0.01 A/F from −1.21 ± 0.08 A/F (n = 5, p < 0.05) and membrane potential at which 50% of the channels are activated (V0.5) diminished to -13.06 ± 1.52 mV from -19.26 ± 1.72 mV (n = 5, p < 0.001) not altering the slope factor. Furthermore, cardiomyocytes exposure at 30 μM quercetin presented [Ca2+]i transient of 4.61± 0.22 (n = 91 cells, p < 0.001) that was 28% higher compared with control situation (3.60 ± 0.14, n = 40 cells). Quercetin also accelerated the [Ca2+]i transient decay kinetics at 90% (t90) from 875.8 ± 13.44 ms to 740.0 ± 26.74 ms (p < 0.001) and at 50% (t50) from 253.3 ± 7.75 ms to 181.4 ± 12.67 ms (p < 0.001). In cardiomyocytes not electrically stimulated, quercetin did not increase the frequency of calcium sparks. In isolated guinea pig heart, quercetin increased the heart rate from 133.1 ± 5.49 bpm to 146.2 bpm ± 5.28 (n = 5, p <0.0001); decreased the PR interval from 107.3 ± 4.69 ms to 100.3 ± 1.79 ms (n = 5, p < 0.05) and decreased the QTc from 10.49 ± 0.048 ms to 10.23 ± 0.06 ms. The duration of the QRS complex was not significantly changed, and there was also no evidence of the appearance of cardiac arrhythmias. Thus, we showed that quercetin activates β-adrenergic receptors, leading to increased L-type calcium current and intracellular calcium transient, not inducing the increase of calcium sparks or arrhythmogenic effects. / A quercetina é um flavonoide, amplamente distribuído nas plantas e apresenta várias atividades biológicas. Esse trabalho tem como objetivo descrever os efeitos da quercetina sobre as propriedades contráteis e eletrofisiológicas do músculo cardíaco, assim como a homeostase do cálcio intracelular. Nesse estudo, foi avaliado o efeito inotrópico da quercetina em átrio esquerdo de cobaia, sua ação nos receptores adrenérgicos e sobre os parâmetros eletrocardiográficos. Em cardiomiócito ventricular de camundongo, foram estudadas as correntes de Ca+2 tipo-L (ICa,L), o transiente intracelular global de cálcio e as sparks de cálcio. Os resultados revelaram que a quercetina promoveu efeito inotrópico positivo (EC50 3,64 x 10-6 M, n = 4) que foi significativamente reduzido pelo propranolol a 1 M. Além disso, a quercetina induziu relaxamento diastólico (~7%). Em cardiomiócito ventricular, 30 μM de quercetina promoveu aumento da densidade da ICa,L em 0 mV de -0,95 ± 0,01 A/F para -1,21 ± 0,08 A/F (n = 5, p < 0,05) e o potencial de membrana, onde 50% dos canais estão ativados (V0,5) diminuiu de -13,06 ± 1,52 mV para -19,26 ± 1,72 mV (n = 5, p < 0,001) sem alterar a inclinação da curva. Além disso, os cardiomiócitos expostos a 30 μM de quercetina apresentaram um transiente intracelular de cálcio de 4,61 ± 0,22 (n = 91 células, p < 0,001) que foi 28% maior comparado com cardiomiócito na situação controle (3,60 ± 0,14, n = 40 células). A quercetina também acelerou a cinética do decaimento do transiente da Ca+2, em 90% (t90) foi reduzido de 875,8 ± 13,44 ms para 740,0 ± 26,74 ms (p < 0,001) e em 50% (t50) de 253,3 ± 7,7 ms para 181,4 ± 12,67 ms (p < 0,001). Em cardiomiócito não estimulados eletricamente, a quercetina não aumentou a frequência de sparks de cálcio. Em coração isolado de cobaia, a quercetina aumentou a frequência cardíaca de 133,1 ± 5,49 bpm para 146,2 ± 5,28 bpm (n = 5, p < 0,0001); diminuiu o intervalo PR de 107,3 ± 4,69 ms para 100,3 ± 1,79 ms (n = 5, p < 0,05); diminuiu o QTc de 10,49 ± 0,048 ms para 10,23 ± 0,06 ms. A duração do complexo QRS não apresentou alteração significativa, assim como não foi evidenciado o aparecimento de arritmias cardíacas. Assim, evidenciamos que a quercetina ativa receptores β-adrenérgicos, levando ao aumento da corrente de cálcio tipo-L e do transiente intracelular de cálcio, sem induzir o aumento de sparks de cálcio ou efeitos arritmogênicos.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The farnesol (C15H26O) is a sesquiterpene alcohol found in herbs and essential oils. Research show some beneficial properties of farnesol as: antioxidant, anti-inflammatory and chemopreventive properties. However, the farnesol futher inhibition of activity of L-type calcium channels in smooth muscle. This study sought to analyze the involvement of calcium channels L-type in the cardiodepressant farnesol response in the rat heart. To this, contractile studies were conducted on left atria drawn to rest tension 5mN (0,5gf) and subjected to field stimulation with above-threshold current pulses of the 1 Hz, kept in isolated organ vessel, submerged in Krebs-Henseleit solution (8 mL) and aerated with carbogênica mixture (95% O2 and 5% CO2). The atrial contraction force was capture by an isometric transducer. Electrocardiographic recordings were performe on isolated heart, aortic perfusion under a constant flow (10 ml / min) Langendorff type system. The hearts were keep spontaneously beating, to determine the heart rate, and in heart stimulated were determined PR interval (PRI), QT (QTi) and complex QRS. Left ventricular pressure was determined in the heart stimulated electrically by means of a balloon inflated with water at a pressure of 15 cmHg. In rat left atrium, the farnesol response to the contraction strength showed a negative inotropic effect, reducing the contraction force at 41.63% at the maximum concentration used, with an EC50 of 2.84 ± 0.19 mM. To evaluate the effect of farnesol of the positive inotropic response of CaCl2 and (±)-Bay K8644 was observed that the farnesol shifted to the right CaCl2 concentration-response curve and decreased maximum efficiency (100% to 23%) and abolished curve of (±)-Bay K8644. TEA was use to evaluate the role of K+ channels in the negative inotropic response and the maximum effect by farnesol (41.63 to 63.02%) was increased. In isolated heart, there was an increase of PRI, QTi and QRS complex, and reduced left ventricular pressure (37, 38%) and heart rate (25.22%). Thus, farnesol exerts inotropic and negative chronotropic responses in the heart by reducing current to the L-type Ca2+. / O farnesol (C15H26O) é um álcool sesquiterpênico encontrado em óleos essenciais e ervas aromáticas. Pesquisas evidenciam algumas propriedades benéficas do farnesol como: propriedades antioxidantes, anti-inflamatórias e quimiopreventivas. Entretanto, o farnesol promoveu inibição dos canais de cálcio tipo-L em músculo liso. Neste trabalho procurou-se analisar os efeitos do farnesol sobre os mecanismos contráteis e eletrofisiológicos sobre o coração de rato. Para esse fim, os estudos contráteis foram realizados em átrios esquerdo estirados a para uma tensão de repouso de 5mN (0,5gf) e submetidos a estimulação de campo com pulsos de corrente supralimiares de 1 Hz, mantido em cuba para órgão isolado, submerso em solução de Krebs-Henseleit (8 mL) e aerado com mistura carbogênica (95 % O2 e 5 % CO2). A força de contração atrial foi captada por um transdutor isométrico. Os registros eletrocardiográficos foram obtidos em coração isolado, sob perfusão aórtica de fluxo constante (10 mL/min), em sistema de Langendorff. Os corações foram mantidos com batimento espontâneo, para determinar a frequência cardíaca, e em corações estimulados foram determinados os intervalos PR (PRi), QT (QTi) e complexo QRS. A pressão ventricular esquerda foi determinada, em coração estimulado eletricamente, por meio de um balonete insuflado com água até uma pressão de 15 cmHg. Em átrio esquerdo de rato, a resposta do farnesol sobre a força de contração apresentou efeito inotrópico negativo, diminuindo a força de contração em 41,63% na concentração máxima usada, apresentando uma CE50 de 2,843 ± 0,19 mM. Ao avaliar o efeito do farnesol sobre a resposta inotrópica positiva do CaCl2 e (±)-BAY K8644 foi observado que o farnesol deslocou para direita a curva concentração-resposta do CaCl2 e diminuiu a eficácia máxima (100% para 23%) e aboliu a curva do (±)-BAY K8644. Para avaliar a participação dos canais para potássio na resposta inotrópica negativa foi utilizado TEA tendo aumento da eficácia máxima do farnesol de 41,63 para 63,02%. Em coração isolado, foi observado aumento do PRi, QTi e complexo QRS, e redução da pressão ventricular esquerda (37,38%) e frequência cardíaca (25,22%). Assim sendo, o farnesol exerce respostas inotrópicas e cronotrópicas negativas no coração, por redução das correntes para Ca2+ tipo-L.

Made available in DSpace on 2016-08-17T14:53:06Z (GMT). No. of bitstreams: 1 Fausto Lucena de Oliveira.pdf: 744487 bytes, checksum: 189e44c92f58b262f0b8901410cec223 (MD5) Previous issue date: 2006-02-23 / The estimation of heart rate variability (HRV) makes use of the RR intervals obtained from the electrocardiogram (ECG) and prevails as a standard procedure to analyze the modulation regulated by the autonomous nervous system. Moreover, many works have been trying to show that is possible to obtain the HRV from the systolic blood pressure (SBP). Those works often present results of the comparison in the time and frequency domains between the HRV calculated from the RR intervals and the discrete series composed by the maximum values of SBP. However, these comparisons were shown to be reliable only over time domain, for they exhibit disparities on the high frequency bands. In this work we show that the reported disparities on high frequencies could be related to many procedures adopted during the processing of these signals to extract the intervals referred to the cardiac cycles. Here, we use a recent technique called heart instantaneous frequency, proposed to calculate the HRV from both ECG and blood pressure (BP) signals, with the benefit of being more robust to undesired artifacts than the usual peak detectors. Then, we present temporal and spectral results with nonsignificant statistical differences between the HRV extracted from both ECG signals using peak detectors and BP waveforms using the HIF algorithm. / O calculo da variabilidade de frequencia cardıaca (HRV) se utiliza dos intervalos RR obtidos a partir do eletrocardiograma (ECG) e prevalece como um procedimento padrão para se analisar a modulação do sistema nervoso autonomo. Apesar disso, um grande numero de trabalhos tem tentado mostrar que é potencialmente útil obter a HRV a partir da pressão sanguinea sistólica (PSS). Estes estudos geralmente apresentam resultados da comparação no domınio do tempo e frequencia entre a HRV obtida a partir dos intervalos RR com a serie discreta formada pelos valores maximos da PSS. Entretanto, essas comparações mostraram haver apenas confiabilidade nos parametros temporais, pois apresentam disparidades nas bandas de alta frequencia. Neste trabalho, nós mostramos que as diferenças apresentadas nas altas frequencias podem estar relacionadas com os vários procedimentos adotados durante o processamento desses sinais ao se extrair os intervalos referentes aos ciclos cardıacos. Aqui, nós usamos uma técnica recente denominada de frequencia instantanea cardıaca (HIF, do inglês heart instantaneous frequency), que foi proposta para se calcular a HRV tanto com sinais de ECG quanto de pressão sanguınea (PS), com a vantagem de ser mais robusta aos artefatos indesejados que os usuais detectores de pico. Assim, nós mostramos resultados temporais e espectrais com diferenças estatısticas insignificantes entre a HRV extraıda a partir do ECG usando detectores de pico com os obtidos pelas formas de onda de PS usando o algoritmo HIF.

Obstruções uretrais em felinos geralmente são secundárias à doença do trato urinário inferior felino (DTUIF), afecção comum em gatos. A doença pode ser auto-limitante, mas a obstrução uretral leva à parada da função renal, gerando uma série de distúrbios no organismo, que necessitam tratamento imediato. A maioria dos estudos sobre as alterações decorrentes da obstrução foi feito em animais em estado crítico ou experimentalmente. O objetivo do presente estudo foi descrever as principais alterações observadas em gatos obstruídos atendidos na rotina clínica e correlacioná-las. Foram avaliados 32 gatos machos com obstrução uretral e sem tratamento prévio. A avaliação constou de exame clínico, hemograma, bioquímica sérica (uréia, creatinina, proteína total, ALT, AST, fosfatase alcalina, sódio, potássio, cálcio, fósforo, magnésio, glicemia e lactato), gasometria venosa, exame e cultura de urina e eletrocardiograma (ECG). Os animais foram agrupados conforme o tempo de obstrução (mais e menos de 36 horas). As alterações mais comuns no histórico foram disúria (100% dos animais), disorexia (84,4%), apatia (71,8%), vocalização (68,7%) e oligodipsia (68,7%); no exame físico, desidratação (71,8%), taquipnéia (53,1%) e hipotermia (53,1%). As alterações laboratoriais mais freqüentes foram hipermagnesemia (100%), acidose metabólica (89,6%), hiperglicemia (88,9%), hiperazotemia (84,4%) e hiperpotassemia (80,6%). Vinte por cento dos gatos tinham infecção urinária. Alterações no ECG foram evidenciadas em 39,3% dos casos, sendo a parada atrial com ritmo sinoventricular a mais freqüente. Não houve relação entre as alterações no ECG e os níveis de potássio sérico. A análise dos grupos sugere agravamento da hiperazotemia, hiperpotassemia, hipermagnesemia e do estado geral com a evolução do processo. Nas correlações, a temperatura e a freqüência cardíaca apresentaram relação direta com pH sanguíneo, excesso de base e bicarbonato, e relação inversa com uréia, creatinina, potássio e fósforo. A uréia e creatinina se correlacionaram inversamente com sódio, pH sanguíneo, excesso de base e bicarbonato, e diretamente com potássio e fósforo. O estado geral correlacionou-se com a temperatura, uréia, creatinina, potássio, pH sanguíneo, excesso de base e bicarbonato. / Urethral obstruction is a frequent complication in cats with feline lower urinary tract disease (FLUTD), considered a common disease in cats. Most cases are self-limiting, but the urethral obstruction causes renal failure and metabolic alterations which needs immediate treatment. Previous reports selected cats that were critically ill or had a experimental induction of the disease. The goal of this study was to describe the clinical signs, laboratory and electrocardiographyc abnormalities in cats with urethral obstruction and to correlate these results. Thirty-two male cats with natural urethral obstruction and without previous therapy were studied. Complete blood count, serum chemistry profile (urea, creatinine, plasma protein, alanine transferase, aspartate transferase, alkaline phosphatase, sodium, potassium, calcium, phosphorus, magnesium, glucose and lactate), venous blood gas, urinalysis, urine culture and electrocardiogram (ECG) were performed. Two groups of 16 cats were composed (animals under and over 36 hours of obstruction). The most frequent abnormalities described were dysuria (100%), anorexia (84,4%), lethargy (71,8%), vocalization (68,7%), hypodipsia (68,7%), and dehydration (71,8%), tachypnea (53,1%) and hypothermia (53,1%) in physical evaluation. The laboratorial abnormalities most frequently observed were hypermagnesemia (100%), metabolic acidosis (89,6%), hyperglicemia (88,9%), azotemia (84,4%) and hyperkalemia (80,6%). Twenty per cent of cats had urinary infections. Abnormalities in ECG, such as atrial standstill with sinoventricular rhythm, were seen in 39,3% of cases, and there were no correlation with hyperkalemia. The analyses of the groups suggest worsening of azotemia, hyperkalemia, hypermagnesemia and lethargy with evolution of obstruction. Temperature and heart rate were positively correlated with blood pH, base excess and bicarbonate, and inversely correlated with urea, creatinine, potassium and phosphorus. Lethargy was correlated with temperature, blood pH, base excess and bicarbonate.

Le niveau de risque dans l'HTA est lié en partie au niveau de pression artérielle systolique (PAS) et diastolique (PAD) mais également aux atteintes d'organes cibles infracliniques. Les objectifs de ce travail sont de rechercher des facteurs pronostiques concernant le remodelage du ventricule gauche et de l'aorte dans le cadre des pathologies cardiovasculaires. Les résultats ont été obtenus à partir de la cohorte historique OLD-HTA constituée au début des années 1970 et des patients pris en charge actuellement dans le service de cardiologie. Concernant le remodelage ventriculaire gauche, nous démontrons que l'onde R aVL sur l'ECG est corrélé à l'hypertrophie ventriculaire gauche en s'appuyant sur l'IRM cardiaque comme gold standard et qu'elle permet de prédire la mortalité toute cause et cardiovasculaire dans l'HTA. D'autre part, nos résultats permettent de mieux appréhender la valeur pronostique de la PAD qui devient un élément protecteur pour une PAS donnée en cas d'athérome aortique. Enfin, nous démontrons que la présence d'athérome aortique ou de calcifications aortiques est un élément prédicteur d'événements cardiovasculaires dans les suites d'un remplacement valvulaire aortique percutané et lorsque la fréquence cardiaque est élevée chez le patient hypertendu. L'ensemble de ces éléments pronostiques permettra à l'avenir de mieux stratifier le risque cardiovasculaire de nos patients en évaluant afin de leur proposer les thérapeutiques les plus adaptées / Risk stratification in hypertension is related to the level of systolic blood pressure (SBP) and diastolic blood pressure (DBP) but also to the presence of subclinical target organ damages. The aims of the studies conducted were to determine the prognostic values of left ventricular and aortic remodeling in the clinical setting of cardiovascular disease. Results were obtained in our historic OLD-HTA cohort started in the 70’s and with patients currently treated in our cardiology department. Regarding left ventricular remodeling, we demonstrated that R wave in aVL lead from the electrocardiogram is a robust index of left ventricular hypertrophy using cardiac MRI and this index is also a powerful predictor of all-cause and cardiovascular mortality in hypertension. Moreover, our results indicated that at a specific level of SBP, a low DBP is harmful in the presence of aortic atheroma. Therefore, aortic atherosclerosis or aortic calcifications are a major predictor of cardiovascular events after transcutaneous aortic valve implantation and in hypertensive patients with high resting heart rate. Taken together these data emphasize the interplay between aorta and the heart and provide some new hints to improve risk stratification particularly in hypertension