Estudos relatam alterações cardiovasculares após a estimulação química ou elétrica do córtex pré-límbico (PL) em ratos. O sistema renina-angiotensina (SRA) central está envolvido na regulação do sistema cardiovascular, tendo como um dos principais componentes ativos desse sistema a angiotensina II (ANGII). Além disso, foi demonstrada a presença de um sistema SRA funcional no PL, com a presença de peptídeos e receptores angiotensinérgicos. Sendo assim, o objetivo do presente estudo foi investigar se a estimulação do PL com ANG II induz respostas cardiovasculares mediadas por ativação do sistema nervoso simpático ou por liberação de vasopressina. A microinjeção de ANGII no PL de ratos não anestesiados causou resposta pressora e bradicardíaca de forma dose-dependente. O pré-tratamento sistêmico com o bloqueador ganglionar, pentolínio (5mg/Kg), não alterou a resposta pressora, mas bloqueou a resposta bradicárdiaca causada pela microinjeção de ANGII no PL, sugerindo que o sistema nervoso simpático não medeia a resposta pressora. Além disso, o pré-tratamento sistêmico com antagonista dos receptores vasopressinérgicos do tipo V1, o dTyr(CH2)5(Me)AVP (50 g/kg), bloqueou as respostas cardiovasculares causadas pela microinjeção de ANGII no PL, demonstrando o envolvimento do mecanismo vasopressinérgico humoral na mediação destas respostas. Centralmente, o pré-tratamento do PL com o antagonista AT1, candesartan, bloqueou a resposta cardiovascular induzida pela microinjeção de ANGII, assim como o pré-tratamento com CGP42112A, antagonista AT2, foi capaz de atenuar as respostas cardiovasculares induzidas pela microinjeção de ANGII, sugerindo o envolvimento de ambos os receptores no desencadeamento dessas respostas cardiovasculares. Foi investigada a participação do sistema noradrenérgico no desencadeamento das respostas cardiovasculares à ANGII, através da administração local de um antagonista de receptores 1- adrenérgicos, o WB4101; o qual foi efetivo em reduzir a resposta pressora sem alterar a resposta bradicardíaca à ANGII. Em conclusão, a administração de ANGII no PL de ratos não-anestesiados, através da estimulação de receptores AT1 e AT2, evoca respostas pressoras e bradicardíacas mediadas por liberação sistêmica de vasopressina, envolvendo também a participação do sistema noradrenérgico do PL. / Previous studies have reported cardiovascular responses after chemical or electrical stimulation of the prelimbic cortex (PL) in rats. The central renin-angiotensin system (RAS) is involved in the regulation of the cardiovascular system, being angiotensin II (ANG II) one of the major active components of this system. Furthermore, there are angiotensinergic receptors and peptides in the PL, indicating the presence of a functional RAS in this brain area. Thus, the aim of this study was to investigate if the PL stimulation with ANG II induces cardiovascular responses mediated by activation of the sympathetic nervous system or through the release of vasopressin. ANG II microinjection into the PL of anesthetized rats caused pressor and bradycardiac responses, in a dose-dependent manner. Systemic pretreatment with the ganglionic blocker pentolinium (5 mg / kg) did not affect the pressor response, but blocked the bradycardiac response induced by ANG II, suggesting that the sympathetic nervous system does not mediate the pressor response. Furthermore, systemic pretreatment with the V1-vasopressinergic receptor antagonist, dTyr (CH2) 5 (Me) AVP (50 mg / kg) blocked the cardiovascular responses caused by the microinjection of ANG II into the PL, demonstrating the involvement of the humoral vasopressinergic mechanism in the mediation of these responses. PL pretreatment with the AT1 antagonist candesartan blocked the cardiovascular response induced by the microinjection of ANG II, while PL pretreatment with CGP42112A, an AT2 antagonist, attenuated the cardiovascular responses induced by microinjection of ANG II, suggesting the local involvement of both receptors in triggering these cardiovascular responses. We also investigated the participation of the local noradrenergic system in the triggering of cardiovascular responses to ANG II pretreating the PLwith the 1- adrenergic receptor antagonist WB4101. The pretreatment with WB4101 reduced the pressor response without changing the bradycardiac response. In summary, administration ANG II into the PL of non-anesthetized rats evoked pressor and bradycardiac responses mediated by local stimulation of AT1 and AT2 receptors, with concomitant involvement PL noradrenergic mechanisms, and systemic release of vasopressin.

Esforços físicos prolongados em ritmo dinâmico parecem promover menor demanda metabólica, estresse fisiológico e cardiovascular comparado a tarefas em ritmo constante. Contudo, os mecanismos não são completamente descritos. Além disso, sugere-se que o tempo que o indivíduo é capaz de suportar um exercício em intensidade máxima (TLim[FCmax]) correlaciona-se com o desempenho no ciclismo. Assim, os objetivos do presente estudo foram verificar como a estratégia de prova (EP) influencia nas respostas fisiológicas, no controle autonômico cardiovascular e no desempenho de tarefas aeróbias subseqüentes. Adicionalmente, verificar se o Lim[FCmax] correlaciona-se com o desempenho em teste contrarelógio de 3 km (CR3KM). Participaram desse estudo oito ciclistas treinados masculinos. Após avaliações antropométricas e familiarização com os cicloergômetros, os indivíduos foram submetidos: (i) teste máximo progressivo para determinação da potência aeróbia máxima e dos limiares metabólicos; (ii) teste TLim[FCmax]; (iii) teste de 20 km adotando diferentes EP, mas mantendo a potência média em todas as sessões; (iv) teste CR3KM realizado 30 minutos após as EP. A frequência cardíaca (FC), a variabilidade da FC, a percepção de esforço (PSE) e o lactato sanguíneo [Lac] foram registrados em todas as situações experimentais. A transformada de Fourier e a amostragem entrópica foram empregadas para analisar a VFC, ao passo que a FC foi descrita por função exponencial. Adicionalmente, a ANOVA two way (estratégia de prova x distância) e a correlação produto momento de Pearson foram utilizadas para comparações estatísticas. Para todas as análises, foi assumido um p < 0,05. Os principais achados foram que o TLim[FCmax] não correlacionou-se o desempenho do CR3KM, a EP não modificou o teste CR3KM subseqüente. No entanto, houve menores incrementos de [Lac], FC e PSE na EP positiva. Possivelmente o início rápido na EP positiva reduz o déficit anaeróbio de oxigênio, reduzindo a contribuição glicolítica nesse período inicial. Finalmente, a VFC apresentou menor complexidade imediatamente após a tarefa, comparado ao repouso e aos minutos finais de recuperação, indicando maior redundância do sistema na tentativa de evitar eventos catastróficos ao organismo / Prolonged physical efforts in variable pacing promote lower metabolic demand, physiological and cardiovascular stress compared with workouts in even pacing. However, the mechanisms is not completely understanding. Additionally, one suggests that the period of time that someone can support exercises in maximal intensity (TLim[FCmax]) could be correlate with performance on the cycling. Thus, the objectives of this study were verified if the pacing strategy (EP) could influence the physiological responses, cardiovascular autonomic control and the performance of the subsequent aerobic exercises. Additionally, to verify the correlation between TLim[FCmax] with the performance on time trials of 3 km (CR3KM). Eight male trained cyclists took part of this study. After anthropometric tests and familiarization with the ergometers, the subjects were submitted: (i) maximal progressive test to determinate the maximal aerobic power and metabolic thresholds; (ii) TLim[FCmax] test; (iii) 20 km test taken different EP, but keeping the average power output in all sessions; (iv) CR3KM test performed 30 minutes after EP. The heart rate (FC), the heart rate variability (VFC), the perceived of effort (PSE) and the blood lactate [Lac] were recorded in all experimental tests. The fast Fourier transformer and the sample entropy were used to analyze the VFC, whilst the FC was analyzed employing exponential function. Further, the ANOVA two way (pacing strategy x distance) and the Pearson product moment correlation were used to statistical comparison. For all the analysis, we assumed p < 0,05. The mains finding were that TLim[FCmax] did not correlate with performance on the CR3KM and the EP did not modify the subsequent CR3KM test . However, there was lower increment for [Lac], FC and PSE on positive EP. Possibly the fast start in the positive EP reduce the anaerobic oxygen deficit, narrowing the glycolytic contribution on the initial effort. Finally, the VFC showed lower complexity immediately after the workout than the rest and the last minutes of recovery, suggesting higher redundancy of the system, probably trying avoid catastrophic occurrence to the organism

Nesta tese, medidas hemodinâmicas como o débito cardíaco (DC), o volume sistólico (VS) não invasivo, os índices representativos da modulação vagal (RMSSD e SD1), a VFC total (SD2) e a função endotelial por meio da vasodilatação mediada por fluxo (FMD) da artéria braquial (%FMD) foram estudados nas primeiras 24h do diagnóstico de sepse. Foram avaliados 60 pacientes e acompanhados até o 28° dia. O DC e o VS foram obtidos batimento a batimento por meio da cardioimpedância. Os intervalos RR foram captados por um monitor cardíaco e transferidos para um software para processamento dos índices de VFC. O ultrassom Doppler foi utilizado para avaliar a % da FMD. Os resultados mostraram que 65% dos pacientes foram a óbito. No grupo não sobrevivente (GNS) foram observados menores valores de VS, RMSSD, SD1, índice triangular de RR, e SD2, bem como maiores valores de FC (P<0,05). Além disso, observamos que a %FMD apresentou-se reduzida para este grupo (GNS). Os índices RMSSD e SD1 foram preditores da %FMD, delta FMD e FMDpico. Valores de corte de RMSSD<11,2, SOFA>9 e %FMD>2,9 foram preditores de risco de morte em pacientes com sepse. Os dados sugerem que os índices representativos da modulação vagal, assim como a função vascular precoce podem ser marcadores de mortalidade na sepse. / In this thesis, hemodynamic measures such as cardiac output (DC), noninvasive stroke volume (SV), indices representative of vagal modulation (RMSSD and SD1), total HRV (SD2) and endothelial function through by flow mediated dilation (FMD) of the brachial artery (% FMD) were studied in the first 24 hours of the diagnosis of sepsis. Sixty patients were evaluated and followed up until the 28th day. The CO and SV were obtained beat-to-beat by cardio-impedance method. The RR intervals were captured by a cardiac monitor and transferred to a software for processing the HRV indices. Doppler ultrasound was used to evaluate the% of FMD. The results showed that 65% of the patients died. In the non-surviving group (NSG), lower values of SV, RMSSD, SD1, triangular index of RR, and SD2 were observed, as well as higher HR values (P<0.05). In addition, we observed that% FMD was reduced for this group (NSG). The RMSSD and SD1 indices were predictors of% FMD, delta FMD and peak of FMD. Cut-off values of RMSSD <11.2, SOFA> 9 and% FMD> 2.9 were predictors of death risk in patients with sepsis. The data suggest that representative indices of vagal modulation as well as early vascular function may be markers of mortality in sepsis.

O objetivo do presente estudo foi verificar a possibilidade de identificação dos dois limiares metabólicos pelo comportamento da VFC. Para isso, 22 voluntários do gênero masculino [74,5 + 7,99kg, 177,0 + 8cm, 23,86 + 1,69 (índice de massa corporal) e 9,10 % de gordura], habituados à prática do ciclismo, realizaram teste ergométrico em bicicleta estacionária com carga inicial de 120W e incrementos de 30W a cada 3min, até a exaustão. Durante todo o teste foram feitos os registros da freqüência cardíaca (FC) e de sua variabilidade (VFC) e ao final de cada carga foram coletados 25µL de sangue para análise da concentração sangüínea de lactato. Aplicou-se um modelo matemático que ajustou a curva da VFC em três retas e o primeiro e segundo limiar de VFC foram identificados nas intersecções entre as retas. Para identificação do primeiro e segundo limiar de lactato, considerou-se as concentrações fixas de 2,0 e 3,5mM, respectivamente. A análise de variância para medidas repetidas indicou não haver diferenças significativas nas cargas em que os limiares de VFC e de lactato foram encontrados, mostrando que a metodologia proposta pode ser promissora. Entretanto a falta de correlação entre as variáveis indica que novos estudos necessitam ser realizados para confirmação desta possibilidade. / The purpose of this study was to verify the possibility of metabolic thresholds identifications through HRV. For that, 22 male volunteers [74,5 + 7,99kg, 177,0 + 8cm, 23,86 + 1,69 (body mass index) e 9,10 % fat], familiarized to cyclism practice, realized a cycloergometer test with initial load of 120W and 30W increases every 3min., until exhaustion. During all test, it was registered heart rate (HR) and its variability (HRV) and, at the end of each load, it was collected 25mL blood for lactate concentration analysis. It was applied a mathematical model to adjust HRV curve in three straight lines and first and second HRV thresholds were identified in intersections among the lines. For the identification of first and second lactate thresholds, it was considered 2,0 and 3,5mM fixed concentrations, respectively. Variance analysis for repeated measures indicated that there were no significant differences between loads in which HRV and lactate thresholds were found, showing that purposed methodology can be promissor. However, the lack of correlation between variables indicate that new studies must be made to confirm that possibility.

Trata-se de estudo prospectivo, comparativo da resposta da freqüência cardíaca fetal (FCF) à estimulação vibratória e sônica, quanto à amplitude e duração, em 113 fetos de gestações de baixo risco. A população estudada foi discriminada em quatro grupos: 1) 25 semanas a 28 semanas e seis dias; 2) 29 semanas a 32 semanas e seis dias; 3) 33 semanas a 36 semanas e seis dias e 4) 37 a 42 semanas. Comparando-se a amplitude e a duração da resposta da FCF na faixa três e na faixa quatro, a resposta à estimulação vibratória foi menor que a sônica. Nas faixas um e dois não houve diferença nas respostas. Conclui-se que a estimulação vibratória promove resposta fetal (FCF) menos intensa com amplitude e duração de resposta menor quando comparada à estimulação sônica em faixa de idade gestacional mais tardia / This prospective study compares the response in terms of fetal heart rate acceleration after vibratory and sonic stimulation, in a sample of 113 fetuses of low-risk pregnancies. The study population was divided into four groups according to gestational age: group 1 - 25 weeks to 28 weeks and 6 days; group 2 - 29 weeks to 32 weeks and 6 days; group 3 - 33 weeks to 36 weeks and 6 days, and group 4 - 37 to 42 weeks. Comparing the amplitude and duration of the cardioacceleratory response between group 3 and 4, the response after vibratory stimulation was lower than sonic. In the groups 1 and 2, the response was similar. The study concludes that vibratory stimulation promotes a less intense response with amplitude and duration lower than sonic stimulation in latter gestational age

O objetivo deste estudo foi avaliar os efeitos cardiovasculares da infiltração maxilar usando lidocaína 2% associada à epinefrina 1:100.000, articaína 4% associada à epinefrina 1:100.000 e 1:200.000 em diferentes etapas da consulta odontológica para realização de procedimento restaurador. Vinte voluntários receberam, aleatoriamente, 1,8 ml dos três anestésicos locais. A pressão arterial sistólica, diastólica e média e a freqüência cardíaca foram avaliadas pelos métodos oscilométrico e fotopletismográfico em sete etapas da consulta odontológica. A análise estatística dos parâmetros cardiovasculares através dos testes ANOVA e Tukey não mostrou diferenças significativas entre as três soluções anestésicas. Houve diferença estatisticamente significante para os parâmetros cardiovasculares entre as diferentes etapas clínicas da consulta odontológica. A variação dos parâmetros cardiovasculares é semelhante para as soluções de articaína e lidocaína associadas à epinefrina e é influenciada pelas etapas da consulta odontológica. / The aim of this study was to evaluate cardiovascular effects by maxillary infiltration using 2% lidocaine with 1:100.000 epinephrine, 4% articaine with 1:100.000 and 1:200.000 epinephrine in different stages of dental appointment for restorative procedures. Twenty healthy patients randomly received 1,8 ml of the three local anesthetics. Systolic blood pressure, average blood pressure, diastolic blood pressure and heart rate were evaluated by the oscillometric and photoplethysmograph methods in seven stages of the appointment. Statistical analysis by ANOVA and Tukey tests of cardiovascular parameters did not show significant differences between the anesthetic associations. There were significant differences for the parameters among different clinical stages of the dental appointment. The variation of cardiovascular parameters is similar for articaine and lidocaine solutions and it is influenced by the stages of the dental appointment.

Tse On Ki. / Thesis submitted in: June, 1997. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 97-113). / Abstract also in Chinese. / List of Tables --- p.xiii / List of Figures --- p.xiv / List of Abbreviations --- p.xv / Chapter Chapter 1. --- Introduction to thesis --- p.2 / Chapter 1.1 --- Misoprostol --- p.2 / Chapter 1.1.1 --- Description and History of Drug --- p.2 / Chapter 1.1.2 --- Current Use in Obstetrics and Gynaecology --- p.3 / Chapter 1.1.2.1 --- Termination of Pregnancy (TOP) --- p.3 / Chapter 1.1.2.2 --- Cervix Priming prior to Surgical Treatment of Pregnancy Failure --- p.4 / Chapter 1.1.2.3 --- Medical management of spontaneous abortion --- p.4 / Chapter 1.2 --- Gemeprost --- p.4 / Chapter 1.3 --- Doppler Sonography and Assessment of Blood Velocity --- p.5 / Chapter 1.4 --- Overview of Thesis --- p.5 / Chapter 1.5 --- Aim of this Study --- p.8 / Chapter Chapter 2. --- Physiological and Anatomical Features of Pregnancy --- p.10 / Chapter 2.1 --- Cardiovascular System Changes in Pregnancy --- p.10 / Chapter 2.1.1 --- Changes in the Blood --- p.10 / Chapter 2.1.2 --- Changes in Circulation --- p.11 / Chapter 2.1.3 --- The Distribution of Blood Flow in Uterus --- p.12 / Chapter 2.2 --- Blood Supply to Uterus --- p.13 / Chapter 2.3 --- Pelvic Anatomy in Early Pregnancy via Transvaginal Sonography --- p.15 / Chapter 2.3.1 --- Uterus --- p.15 / Chapter 2.3.2 --- The Adnexa --- p.17 / Chapter 2.3.3 --- Other Pelvic Structures --- p.17 / Chapter Chapter 3. --- Prostaglandins and Analogues --- p.19 / Chapter 3.1 --- Natural Prostaglandins --- p.19 / Chapter 3.2 --- The Source of PGs in Reproductive Organs of Women --- p.19 / Chapter 3.3 --- PGs Synthesis and Metabolism --- p.20 / Chapter 3.4 --- PGE1 Analogue: Misoprostol --- p.21 / Chapter 3.4.1 --- Misoprostol --- p.22 / Chapter 3.4.1.1 --- Pharmacology --- p.22 / Chapter 3.4.1.2 --- Adverse Side Effects --- p.23 / Chapter 3.4.1.3 --- Toxicology --- p.23 / Chapter 3.4.1.4 --- Misoprostol in Obstetrics & Gynaecology --- p.24 / Chapter 3.4.1.4.1 --- To Induce Abortion in First and Second Trimesters --- p.24 / Chapter 3.4.1.4.2 --- Cervix Priming prior to Surgical Evacuation of Uterus --- p.27 / Chapter 3.4.1.4.3 --- Medical Management of Miscarriage --- p.28 / Chapter 3.4.1.4.4 --- Induction of Labour with Dead Fetus --- p.29 / Chapter 3.4.1.4.5 --- Induction of labour --- p.29 / Chapter 3.4.2 --- The Potential Dangers of PGE1 analogues --- p.30 / Chapter Chapter 4. --- Doppler Sonography and Parameter Measurements --- p.34 / Chapter 4.1 --- The Principles of Ultrasound and Doppler Sonography --- p.34 / Chapter 4.1.1 --- The Basic Principles of Ultrasound --- p.34 / Chapter 4.1.2 --- Principles of Doppler Sonography --- p.36 / Chapter 4.2 --- Doppler Mode --- p.39 / Chapter 4.2.1 --- Continuous Wave Doppler Imaging --- p.39 / Chapter 4.2.2 --- Pulsed Wave Doppler Systems --- p.39 / Chapter 4.2.3 --- Colour Doppler Sonography (CDS) --- p.40 / Chapter 4.3 --- The Instrument of Doppler Sonography --- p.40 / Chapter 4.4 --- "Resistance Indices - S/D, PI and RI" --- p.42 / Chapter 4.5 --- Flow Measurement of Uterine artery --- p.44 / Chapter 4.5.1 --- Sampling Sites and Waveforms --- p.44 / Chapter 4.5.2 --- Waveform Components --- p.45 / Chapter 4.5.3 --- Identification of the Main Uterine Arteries --- p.45 / Chapter 4.5.4 --- UA Waveform Changes in Normal Pregnancy --- p.46 / Chapter 4.5.5 --- Factors Affecting the UA Waveforms --- p.48 / Chapter 4.5.6 --- Uterine Artery Resistance in Normal Pregnancy and Labour --- p.49 / Chapter 4.5.6.1 --- Uterine Artery Resistance in Normal Pregnancy --- p.49 / Chapter 4.5.6.2 --- Uterine Artery Resistance during normal labour --- p.51 / Chapter 4.5.7 --- Doppler Measure of Fetal Heart Rate --- p.52 / Chapter 4.6 --- Sonography in Estimation of Gestational Age --- p.53 / Chapter Chapter 5. --- Research Protocol --- p.56 / Chapter 5.1 --- The Ethics --- p.56 / Chapter 5.2 --- Apparatus --- p.58 / Chapter 5.3 --- Drug and Dosage --- p.59 / Chapter 5.4 --- Research Protocol --- p.59 / Chapter 5.4.1 --- Subjects --- p.59 / Chapter 5.4.2 --- Transvaginal Scan --- p.60 / Chapter 5.4.3 --- Parameters Measured --- p.61 / Chapter 5.4.4 --- Misoprostol --- p.65 / Chapter 5.5 --- Data analysis --- p.66 / Chapter Chapter 6. --- Results --- p.68 / Chapter 6.1 --- The Patients' Characteristics --- p.68 / Chapter 6.2 --- The Intra-observer Error --- p.70 / Chapter 6.3 --- Results of Study --- p.70 / Chapter 6.3.1 --- Effect of Misoprostol on the S/D ratio of Both Uterine Arteries --- p.70 / Chapter 6.3.2 --- Effect of Misoprostol on the PI of Both Uterine Arteries --- p.73 / Chapter 6.3.3 --- Effect of Misoprostol on Fetal Heart Rate (FHR) --- p.76 / Chapter 6.3.4 --- Left and Right UA-S/D --- p.78 / Chapter 6.3.5 --- Left and Right UA-PI --- p.81 / Chapter 6.3.6 --- The relationship Between Subgroups --- p.84 / Chapter 6.3.7 --- Side Effects of Misoprostol --- p.85 / Chapter 6.3.8 --- The Changes of UA-S/D and UA-PI According to Gestation --- p.86 / Chapter Chapter 7. --- Discussions and Conclusions --- p.89 / Chapter 7.1 --- Difficulties Encountered during Study --- p.89 / Chapter 7.2 --- Results of Study --- p.90 / Chapter 7.3 --- Implications --- p.94 / Chapter 7.4 --- Summary of Thesis --- p.95 / Chapter 7.5 --- Conclusions --- p.96 / Chapter 8. --- References and Appendix --- p.97

by Yeung Yuk-Ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 119-129). / Abstracts in English and Chinese. / Abstract in English --- p.ii / Abstract in Chinese --- p.v / Glossary --- p.viii / Acknowledgements --- p.x / Publications Arising From this Thesis --- p.xii / List of Tables --- p.xviii / List of Figures --- p.xix / Chapter 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Definition of Heart Rate Variability --- p.1 / Chapter 1.2 --- Physiology --- p.1 / Chapter 1.2.1 --- Review of Autonomic Nervous System and Influence of Heart Rate --- p.1 / Chapter 1.2.2 --- The Role of Baroreceptors in the Control of Circulation --- p.4 / Chapter 1.2.3 --- The Control and Physiological Importance of Heart Rate --- p.7 / Chapter 1.2.3.1 --- Normal Heart Rate --- p.7 / Chapter 1.2.3.2 --- Autonomic Control of Heart Rate --- p.8 / Chapter 1.2.3.2.1 --- Sympathetic Effects --- p.8 / Chapter 1.2.3.2.2 --- Vagal Effects --- p.8 / Chapter 1.2.3.3 --- Reflexes Influencing Heart Rate --- p.9 / Chapter 1.2.3.3.1 --- Baroreceptors --- p.10 / Chapter 1.2.3.3.2 --- Chemoreceptors --- p.10 / Chapter 1.2.3.3.3 --- Atrial Receptors --- p.11 / Chapter 1.2.3.3.4 --- Coronary Chemoreflex --- p.11 / Chapter 1.2.3.3.5 --- Other Reflexes --- p.12 / Chapter 1.2.3.4 --- Influence of Complex Events on Heart Rate --- p.12 / Chapter 1.2.3.4.1 --- Respiratory Influence --- p.12 / Chapter 1.2.3.4.2 --- Effects of Decreases in Venous Return --- p.13 / Chapter 1.2.3.4.3 --- Exercise --- p.13 / Chapter 1.2.3.5 --- Physiological Importance of Heart Rate --- p.14 / Chapter 1.3 --- Spectral Analysis of Blood Pressure and Heart Rate Variability in Evaluating Cardiovascular Regulation --- p.14 / Chapter 1.4 --- Clinical Relevance --- p.15 / Chapter 1.4.1 --- Increased Sympathetic Activity --- p.15 / Chapter 1.4.2 --- Reduced Parasympathetic Activity --- p.15 / Chapter 1.4.3 --- Low Heart Rate Variability --- p.16 / Chapter 1.4.4 --- Depressed Baroreflex Sensitivity --- p.17 / Chapter 1.4.5 --- Prognostic Value of Heart Rate Variability in Disease States --- p.17 / Chapter 1.4.6 --- Abnormality of Autonomic Nervous System in Heart Failure --- p.17 / Chapter 2 --- METHODS FOR ASSESSING HEART RATE VARIABILITY --- p.20 / Chapter 2.1 --- Time Domain Analysis of Heart Rate Variability --- p.20 / Chapter 2.1.1 --- Statistical Methods --- p.21 / Chapter 2.1.2 --- Geometric Methods --- p.22 / Chapter 2.2 --- Spectral Analysis of Heart Rate Variability --- p.23 / Chapter 2.3 --- "Nonlinear Indices (fractal, entropy, chaos theory)" --- p.27 / Chapter 3 --- HEART FAILURE --- p.28 / Chapter 3.1 --- Heart Rate Variability in Heart Failure --- p.28 / Chapter 3.2 --- Effect of Changes in Respiratory Frequency and Posture on Heart Rate Variability Analysis in Heart Failure --- p.34 / Chapter 3.3 --- Effect of Respiratory Rates on Baroreceptor Function in Heart Failure --- p.34 / Chapter 3.4 --- Effect of Treatment on Heart Rate Variability in Heart Failure Patients --- p.35 / Chapter 4 --- AIMS --- p.39 / Chapter 4.1 --- Effect of Changes in Respiratory Frequency and Posture on Heart Rate Variability --- p.39 / Chapter 4.2 --- Effect of Slow Breathing --- p.39 / Chapter 4.3 --- Effect of Therapeutic Interventions in Chronic Heart Failure --- p.39 / Chapter 4.3.1 --- A Comparison of Celiprolol with Metoprolol --- p.39 / Chapter 4.3.2 --- A Comparison of Carvedilol with Metoprolol --- p.40 / Chapter 5 --- STUDIES --- p.41 / Chapter 5.1 --- Impact of Changes in Respiratory Frequency and Posture on Power Spectral Analysis of Heart Rate and Systolic Blood Pressure Variability in Normal Subjects and Patients with Heart Failure --- p.41 / Chapter 5.1.1 --- Subjects --- p.41 / Chapter 5.1.2 --- Recording Technique and Protocol --- p.42 / Chapter 5.1.3 --- Signal Acquisition --- p.42 / Chapter 5.1.4 --- Power Spectral Analysis --- p.43 / Chapter 5.1.5 --- Statistical Analysis --- p.46 / Chapter 5.1.6 --- Results --- p.46 / Chapter 5.1.7 --- Discussion --- p.52 / Chapter 5.1.8 --- Summary --- p.56 / Chapter 5.2 --- Slow Breathing Increases Arterial Baroreflex Sensitivityin Patients with Chronic Heart Failure --- p.57 / Chapter 5.2.1 --- Subjects --- p.57 / Chapter 5.2.2 --- Assessment of Baroreflex Sensitivity --- p.57 / Chapter 5.2.3 --- Statistical Analysis --- p.58 / Chapter 5.2.4 --- Results --- p.59 / Chapter 5.2.5 --- Discussion --- p.62 / Chapter 5.2.6 --- Summary --- p.63 / Chapter 5.3 --- β-Blockers in Heart Failure: a Comparison of a Vasodilating β- Blocker with Metoprolol on Heart Rate Variability by 24 Hour ECG Recordings (Time-Domain & Spectral Analysis) --- p.65 / Chapter 5.3.1 --- Trial Design --- p.65 / Chapter 5.3.2 --- Study Patients --- p.65 / Chapter 5.3.3 --- Study Measurements --- p.66 / Chapter 5.3.4 --- Statistical Analysis --- p.67 / Chapter 5.3.5 --- Results --- p.67 / Chapter 5.3.6 --- Discussion --- p.80 / Chapter 5.3.7 --- Summary --- p.81 / Chapter 5.4 --- Effect of β-Blockade on Baroreceptor and Autonomic Function in Heart Failure-Assessment by Short Term Spectral Analysis --- p.83 / Chapter 5.4.1 --- Trial Design and Study Patients --- p.83 / Chapter 5.4.2 --- Recording Technique and Protocol --- p.83 / Chapter 5.4.3 --- "Signal Acquisition, Power Spectral Analysis and Cross Spectral Analysis" --- p.83 / Chapter 5.4.4 --- Reproducibility --- p.84 / Chapter 5.4.5 --- Statistical Analysis --- p.84 / Chapter 5.4.6 --- Results --- p.84 / Chapter 5.4.7 --- Discussion --- p.93 / Chapter 5.4.8 --- Summary --- p.97 / Chapter 5.5 --- β-Blockade in Heart Failure: A Comparison of Carvedilol with Metoprolol on HRV by 24 hour ECG Recordings (Time-Domain & Spectral Analysis) --- p.98 / Chapter 5.5.1 --- Trial Design and Patient Demographics --- p.98 / Chapter 5.5.2 --- Study Measurements --- p.98 / Chapter 5.5.3 --- Statistical Analysis --- p.99 / Chapter 5.5.4 --- Results --- p.99 / Chapter 5.5.5 --- Discussion --- p.105 / Chapter 5.5.6 --- Conclusions --- p.107 / Chapter 5.6 --- Comparison of Carvedilol and Metoprolol on Baroreceptor Gain in Heart Failure by Short Term Spectral Analysis --- p.108 / Chapter 5.6.1 --- Study Design --- p.108 / Chapter 5.6.2 --- Study Patients --- p.108 / Chapter 5.6.3 --- Recording Technique and Protocol --- p.108 / Chapter 5.6.4 --- "Signal Acquisition, Power Spectral Analysis and Cross Spectral Analysis" --- p.108 / Chapter 5.6.5 --- Statistical Analysis --- p.109 / Chapter 5.6.6 --- Results --- p.109 / Chapter 5.6.7 --- Discussion --- p.112 / Chapter 5.6.8 --- Summary --- p.112 / Chapter 6 --- "GENERAL DISCUSSION, LIMITATIONS & CONCLUSIONS" --- p.113 / Chapter 6.1 --- Discussion --- p.113 / Chapter 6.2 --- Conclusions --- p.117 / Chapter 7 --- REFERENCES --- p.119

"As water covers over 75% surface area of the earth, humans have an innate desire to explore the underwater environment for various aims. Physiological responses are induced in humans and animals to adapt to different stresses imposed by the hyperbaric environment. When these stresses become overwhelming, certain hazards can occur to individuals in underwater or in similar hyperbaric environments, and they may include nitrogen narcosis, oxygen toxicity and decompression sickness (DCS). There are evidences showing that the autonomic nervous system (ANS) plays an important role in diving reflex and physiological responses to diving hazards. However, the assessment of the autonomic nervous activity during SCUBA dives and diving-related hazards are mostly absent from the literature. Thus, in order to evaluate the autonomic nervous alterations that may occur during diving, especially during DCS, the following three experiments were performed in this study: the simulated dives of human subjects in a hyperbaric chamber, the SCUBA diving performed in seawater and induced decompression sickness in a swine model. A novel algorithm developed in our lab, principal dynamic mode (PDM) analysis, is applied to the above data. It has been shown that the PDM is able to accurately separate the sympathetic and parasympathetic dynamics of the ANS, and subsequently it is able to obtain a better quantification of the autonomic nervous activity than a current golden-standard approach. Through the study, dominance of the parasympathetic modulation was found in both hyperbaric chamber and SCUBA diving conditions. And more stresses were present in real dives, compared to simulated dives in chamber. In the swine DCS model, we found neurological DCS and cardiopulmonary DCS resulted in different alterations in the ANS. Furthermore, tracking dynamics of the parasympathetic modulations via the PDM method may allow discrimination between cardiopulmonary DCS and neurological DCS, and has potential use as a marker for early diagnosis of cardiopulmonary DCS. "

A wireless, battery operated pulse oximeter system with a forehead mounted optical sensor was designed in our laboratory. This wireless pulse oximeter (WPO) would enable field medics to monitor arterial oxygen saturation (SpO2) and heart rate (HR) information accurately following injuries, thereby help to prioritize life saving medical interventions when resources are limited. Pulse oximeters developed for field-based applications must be resistant to motion artifacts since motion artifacts degrade the signal quality of the photoplethysmographic (PPG) signals from which measurements are derived. This study was undertaken to investigate if accelerometer-based adaptive noise cancellation (ANC) can be used to reduce SpO2 and HR errors induced by motion artifacts typically encountered during field applications. Preliminary studies conducted offline showed that ANC can minimize SpO2 and HR errors during jogging, running, and staircase climbing. An 8th order LMS filter with ì = 0.01 was successfully implemented in the WPO's embedded microcontroller. After real-time adaptive filtering of motion corrupted PPG signals, errors for HR values ranging between 60 - 180BPM were reduced from 12BPM to 6BPM. Similarly, ambient breathing SpO2 errors were reduced from 5% to 2%.