Photoplethysmography (PPG) is a simple means of measuring the pulse wave in humans, exploitable for the purposes of timing the arrival of the pulse at a particular point in the arterial tree, and for pulse contour analysis. This thesis describes a methodology for measuring arterial pulse transit time (PTT) from cardiac ejection to pulse arrival at the finger. It describes the effect on PTT of drug and exercise induced changes in BP. The nature of the relationship between the PPG and arterial pressure is also examined, and the PTT technique extended to assessment of conduit vessel pulse wave velocity (PWV) during exercise. PTT measured from ECG R-wave to PPG finger wave (rPTT) had a negative correlation (R2=0.39) with systolic BP (SBP), unaffected by vasoactive drugs in some but not all persons. rPTT showed similar beat-to-beat variability to SBP, unaffected by drugs. rPTT correlated weakly with diastolic (DBP) and mean (MAP) pressure. Cardiac pre-ejection period (PEP) formed a substantial and variable part of rPTT (12% to 35%). Transit time adjusted for PEP (pPTT) correlated better with DBP (R2=0.41) and MAP (R2=0.45), than with SBP. The PPG wave tracked changes in the peripheral pressure wave. Drugs had little effect on the generalised transfer function (GTF) describing the association between arterial and PPG waves. Strenuous exercise induced a large decrease in rPTT, mainly accounted for by decreases in PEP (53% of the total change in rPTT) and in transit time from aorta to distal brachial artery (33%). In contrast, minimal change in transit time from wrist to finger tip occurred with exercise. Simultaneous ear-finger PPG signals were used to measure conduit artery PWV during exercise. Ear-finger PWV (PWVef) overestimated carotid-radial PWV throughout exertion (overall bias 0.81±1.05ms-1, p<0.001), but the degree of difference remained constant. The increase in PWVef with exercise, was greater (1.18±0.54ms-1, p=0.035) in healthy subjects with a positive cardiovascular family history compared to those without. PPG enables analysis of the pulse contour during exercise, but estimation of the radial pressure wave from finger PPG by use of a GTF derived at rest, resulted in inaccuracy following exertion. These effects were variable and relatively short-lived. Furthermore, a resting GTF used to determine central pressure from the peripheral wave, resulted in underestimation of SBP (-5.9±2.1mmHg) and central pressure augmentation index (-8.3±2.9%), which persisted for 10 minutes post-exercise. rPTT had a negative linear association with SBP (R2=0.94) during strenuous exercise, slightly stronger than during recovery (R2=0.85). Differences existed in area-undercurve of the rPTT/SBP relationship between exercise and recovery, due to discrepancies in rate and degree of recovery of SBP and PEP. The linear relationship between the rPTT/SBP during exercise was affected by aerobic capacity, and the regression slope was less in the anaerobic compared to aerobic phase of exercise due to minimal change in PEP during anaerobic exertion. The correlation between rPTT/SBP did not change with prolonged aerobic exercise. Finally, measures of baroreflex sensitivity during exercise, were not significantly different between actual beat-to-beat SBP and SBP estimated using rPTT. In conclusion, absolute BP cannot be reliably estimated by measurement of rPTT following administration of drugs and during exercise. However, rPTT may have a role in measuring BP variability and in the assessing exercise capacity. PPG may also be useful in determining the effects of exercise on arterial stiffness, and for estimating the pressure wave contour, although its use during exercise for the latter purpose must be treated with caution.

<p> This study examined the effects of isometric handgrip training (IHG) on resting blood pressure and resting arterial compliance in the carotid and brachial arteries of medicated hypertensive individuals. Previous studies found that isometric training reduced resting arterial blood pressure (RBP) in high-normal and medicated hypertensive individuals. Investigators have also found an improvement in central arterial compliance with aerobic training and a reduction in central arterial compliance with age, cardiovascular disease and resistance training. The effects of isometric training on arterial compliance have not been examined previously.</p> <p> Ten participants participated in a one-hand IHG intervention, nine participants in a two-hand IHG intervention and 5 participants served as the non-exercising controls. Each experimental group performed four, 30% maximal voluntary IHG contractions for 2 minutes, 3 days a week, for 8 weeks. The one-hand group trained only their non-dominant hand, while the two-hand group trained both hands. Measurements of resting arterial blood pressure, and cross sectional compliance of the brachial and carotid arteries were made pre-training, after four weeks of training and after the completion of the eight-week training protocol.</p> <p> There were no changes in resting arterial blood pressure after training. Mean carotid and brachial artery diameters did not change with resistance training. There were no significant changes in brachial or carotid cross sectional compliance with isometric training. In conclusion, moderated level isometric training did not elicit changes in resting arterial blood pressure and resting muscular and elastic arterial compliance in medicated hypertensive individuals compared to a non-exercising control group.</p> / Thesis / Master of Science (MSc)

Introdução: A detecção de hipertensão arterial sistêmica (HAS) em crianças vem aumentando e tem sido relacionada ao aumento da prevalência da obesidade na infância. A evidência da transição nutricional em escolares torna importante o desenvolvimento de pesquisas que avaliem a relação entre pressão arterial (PA), crescimento e estado nutricional em escolares. Objetivos: Avaliar a PA, o crescimento e o estado nutricional de crianças de seis e sete anos e de nove e dez anos de idade de escolas públicas de Florianópolis, SC. Métodos: estudo transversal, analítico de uma amostra aleatória e probabilística de 1082 escolares, de dois grupos de idade. Foram avaliados indicadores antropométricos e de composição corporal: peso (P), estatura (E), prega cutânea tricipital (PCT), circunferência da cintura (CC), cintura abdominal (CA), razão de CC/E e CA/E e índice de massa Corporal (IMC), área gorda (AGB) e área muscular do braço (AMB), analisados pelos referenciais da OMS de 2007 e de Frisancho. Os níveis pressóricos foram classificados individualmente em percentis em relação ao referencial norte-americano, para sexo, idade e estatura, segundo o preconizado pelo National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents (NHBPEP). Analisou-se a correlação entre crescimento, estado nutricional, composição corporal e a PA nos dois grupos etários e as relações com peso de nascimento e estado nutricional. A análise de risco para a razão CC/E (sensibilidade e especificidade) foi calculada pela curvas ROC. Resultados: os escolares apresentaram crescimento adequado, superior ao do referencial; observou-se pressão arterial alterada em 13,8 por cento das crianças, com frequência maior para as mais velhas (17,6 por cento ). A análise isolada da PA sistólica e da diastólica revelou a mesma tendência. Quanto ao estado nutricional verificou-se 25,1 por cento das crianças com sobrepeso e 13,0 por cento com obesidade, destas 4,4 por cento apresentavam obesidade grave, mais frequente nos meninos (7,1 por cento ), independentemente da idade. Os níveis de PA (sistólica e/ou diastólica) foram maiores quanto maior o escore z de estatura. Quanto a composição corporal, a PA elevada esteve associada de maneira significante a maiores escores z de IMC, AGB, AMB, PCT, CC, razão da CC/E e CA/E e a uma menor proporção ( por cento ) de AMB. Na Análise de Regressão Múltipla a CC/E mostrou uma OR de 25842,37 e pela curva ROC o ponto de corte otimizado para razão da CC/E foi >0,49, (56,1 por cento de Sensibilidade e 72,6 por cento de Especificidade). Conclusões: Os escolares têm crescimento adequado, superior ao proposto pela OMS e sem relação com o peso de nascimento. Apresentam também prevalência elevada (13.7 por cento ) de pré-hipertensão e hipertensão arterial, que tende a aumentar com a idade. Têm prevalência elevada (42,5 por cento ) de sobrepeso, obesidade e obesidade grave, que é proporcionalmente mais elevada entre meninos (7,1 por cento ). Apresentam maiores níveis de PA quanto maior o seu crescimento em estatura e um maior risco de elevação de PA associado a uma maior massa corpórea, maior AMB e menor proporção ( por cento ) de AMB. A razão de circunferência da cintura para a estatura em escolares além de apresentar correlação com a PA elevada, se mostra, para ambos os sexos e nas diferentes idades, um bom marcador de alterações de pressão arterial. / Introduction: The detection of Systemic Arterial Hypertension (SAH) in children is increasing and is being associated with increased prevalence of obesity in childhood. The evidence of the nutritional transition in schoolchildren makes it important to develop studies to evaluate the relationships between blood pressure (BP), growth and nutritional status of schoolchildren. Objectives: Evaluate BP, growth and nutritional status of children six and seven, and nine and 10 years of age, who attend public schools in Florianópolis, Santa Catarina Method: A cross sectional analytical study of a probabilistic sample of 1,082 school children from two age groups. The following anthropometric and body composition data were evaluated: Weight (W), Height (H), Triceps Skinfold Thickness (TST), Waist Circumference (WC), Abdominal Waist (AW), ratio of WC/H and AW/H, Body Mass Index (BMI), Arm Fat Area (AFA) and Arm Muscle Area (AMA). These measurements were analysed based on the WHO reference (2007) and Frisancho tables. Blood pressure levels were individually classified in percentiles according to the U.S. benchmark test in relation to sex, age and height in line with the recommendations of the National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents (NHBPEP). We analysed the correlation between growth, nutritional status, body composition and BP of the two age groups, as well as the relationship between birth weight and nutritional status. Sensitivity and specificity analyses for the WC/H ratio were calculated by ROC curve. Results: The results showed that the school children had adequate growth and that these measurements were higher than the U.S. benchmark; blood pressure changes were observed in 13.8 per cent of children, most often in the older group (17.6 per cent ). The separate analysis of systolic and diastolic blood showed the same trend. Regarding nutritional status, 25.1 per cent were overweight and 13.0 per cent were obese; 4.4 per cent of the sample evinced severe obesity (more frequent in boys, at 7.1 per cent ) regardless of age. BP levels (systolic/diastolic) were higher in children with high z-scores for height. BP also was significantly associated with higher z-scores for BMI, AFA, AMA, TST and WC, WC/H and AW/H ratio, and an AMA smaller proportion ( per cent ). In the multiple regression analysis, the WC/H and AW/H showed an OR of 25842.37, and in the ROC curve, the optimized cut-off point for the WC/H was > 0.49 (56.1 per cent of Sensitivity and 72.6 per cent of Specificity). Conclusions: The school-children evinced adequate growth, higher than the values proposed by WHO, regardless their birth weight. They also showed a high frequency of pre-high blood pressure and of hypertension (13.7 per cent ), which tends to increase with age. They had a high prevalence (42.5 per cent ) of being overweight and obese, especially severely obese (7.1 per cent higher in boys). They presented greater BP levels associated with a higher stature, as well as an increased risk of BP elevation associated with a higher body mass index, a higher AMB and a smaller AMA proportion ( per cent ). The ratio of waist circumference to height in school aged children, in addition to its correlation with elevated BP, has shown to be a good marker of changes in blood pressure for both sexes and in different age groups.

Introdução: A detecção de hipertensão arterial sistêmica (HAS) em crianças vem aumentando e tem sido relacionada ao aumento da prevalência da obesidade na infância. A evidência da transição nutricional em escolares torna importante o desenvolvimento de pesquisas que avaliem a relação entre pressão arterial (PA), crescimento e estado nutricional em escolares. Objetivos: Avaliar a PA, o crescimento e o estado nutricional de crianças de seis e sete anos e de nove e dez anos de idade de escolas públicas de Florianópolis, SC. Métodos: estudo transversal, analítico de uma amostra aleatória e probabilística de 1082 escolares, de dois grupos de idade. Foram avaliados indicadores antropométricos e de composição corporal: peso (P), estatura (E), prega cutânea tricipital (PCT), circunferência da cintura (CC), cintura abdominal (CA), razão de CC/E e CA/E e índice de massa Corporal (IMC), área gorda (AGB) e área muscular do braço (AMB), analisados pelos referenciais da OMS de 2007 e de Frisancho. Os níveis pressóricos foram classificados individualmente em percentis em relação ao referencial norte-americano, para sexo, idade e estatura, segundo o preconizado pelo National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents (NHBPEP). Analisou-se a correlação entre crescimento, estado nutricional, composição corporal e a PA nos dois grupos etários e as relações com peso de nascimento e estado nutricional. A análise de risco para a razão CC/E (sensibilidade e especificidade) foi calculada pela curvas ROC. Resultados: os escolares apresentaram crescimento adequado, superior ao do referencial; observou-se pressão arterial alterada em 13,8 por cento das crianças, com frequência maior para as mais velhas (17,6 por cento ). A análise isolada da PA sistólica e da diastólica revelou a mesma tendência. Quanto ao estado nutricional verificou-se 25,1 por cento das crianças com sobrepeso e 13,0 por cento com obesidade, destas 4,4 por cento apresentavam obesidade grave, mais frequente nos meninos (7,1 por cento ), independentemente da idade. Os níveis de PA (sistólica e/ou diastólica) foram maiores quanto maior o escore z de estatura. Quanto a composição corporal, a PA elevada esteve associada de maneira significante a maiores escores z de IMC, AGB, AMB, PCT, CC, razão da CC/E e CA/E e a uma menor proporção ( por cento ) de AMB. Na Análise de Regressão Múltipla a CC/E mostrou uma OR de 25842,37 e pela curva ROC o ponto de corte otimizado para razão da CC/E foi >0,49, (56,1 por cento de Sensibilidade e 72,6 por cento de Especificidade). Conclusões: Os escolares têm crescimento adequado, superior ao proposto pela OMS e sem relação com o peso de nascimento. Apresentam também prevalência elevada (13.7 por cento ) de pré-hipertensão e hipertensão arterial, que tende a aumentar com a idade. Têm prevalência elevada (42,5 por cento ) de sobrepeso, obesidade e obesidade grave, que é proporcionalmente mais elevada entre meninos (7,1 por cento ). Apresentam maiores níveis de PA quanto maior o seu crescimento em estatura e um maior risco de elevação de PA associado a uma maior massa corpórea, maior AMB e menor proporção ( por cento ) de AMB. A razão de circunferência da cintura para a estatura em escolares além de apresentar correlação com a PA elevada, se mostra, para ambos os sexos e nas diferentes idades, um bom marcador de alterações de pressão arterial. / Introduction: The detection of Systemic Arterial Hypertension (SAH) in children is increasing and is being associated with increased prevalence of obesity in childhood. The evidence of the nutritional transition in schoolchildren makes it important to develop studies to evaluate the relationships between blood pressure (BP), growth and nutritional status of schoolchildren. Objectives: Evaluate BP, growth and nutritional status of children six and seven, and nine and 10 years of age, who attend public schools in Florianópolis, Santa Catarina Method: A cross sectional analytical study of a probabilistic sample of 1,082 school children from two age groups. The following anthropometric and body composition data were evaluated: Weight (W), Height (H), Triceps Skinfold Thickness (TST), Waist Circumference (WC), Abdominal Waist (AW), ratio of WC/H and AW/H, Body Mass Index (BMI), Arm Fat Area (AFA) and Arm Muscle Area (AMA). These measurements were analysed based on the WHO reference (2007) and Frisancho tables. Blood pressure levels were individually classified in percentiles according to the U.S. benchmark test in relation to sex, age and height in line with the recommendations of the National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents (NHBPEP). We analysed the correlation between growth, nutritional status, body composition and BP of the two age groups, as well as the relationship between birth weight and nutritional status. Sensitivity and specificity analyses for the WC/H ratio were calculated by ROC curve. Results: The results showed that the school children had adequate growth and that these measurements were higher than the U.S. benchmark; blood pressure changes were observed in 13.8 per cent of children, most often in the older group (17.6 per cent ). The separate analysis of systolic and diastolic blood showed the same trend. Regarding nutritional status, 25.1 per cent were overweight and 13.0 per cent were obese; 4.4 per cent of the sample evinced severe obesity (more frequent in boys, at 7.1 per cent ) regardless of age. BP levels (systolic/diastolic) were higher in children with high z-scores for height. BP also was significantly associated with higher z-scores for BMI, AFA, AMA, TST and WC, WC/H and AW/H ratio, and an AMA smaller proportion ( per cent ). In the multiple regression analysis, the WC/H and AW/H showed an OR of 25842.37, and in the ROC curve, the optimized cut-off point for the WC/H was > 0.49 (56.1 per cent of Sensitivity and 72.6 per cent of Specificity). Conclusions: The school-children evinced adequate growth, higher than the values proposed by WHO, regardless their birth weight. They also showed a high frequency of pre-high blood pressure and of hypertension (13.7 per cent ), which tends to increase with age. They had a high prevalence (42.5 per cent ) of being overweight and obese, especially severely obese (7.1 per cent higher in boys). They presented greater BP levels associated with a higher stature, as well as an increased risk of BP elevation associated with a higher body mass index, a higher AMB and a smaller AMA proportion ( per cent ). The ratio of waist circumference to height in school aged children, in addition to its correlation with elevated BP, has shown to be a good marker of changes in blood pressure for both sexes and in different age groups.

<p> Hypertension and reduced arterial distensibility are independent risk factors for cardiovascular disease. Previous research has found that isometric training reduces resting blood pressure (RBP) (Wiley et al. 1992; Taylor et al. 2003) yet the mechanisms responsible remain elusive. Improved arterial distensibility may contribute to this reduction in RBP. The purpose of the present study was threefold: 1) to replicate the RBP lowering effect of isometric handgrip (IHG) exercise; 2) to compare IHG and isometric leg press (ILP) based in their RBP lowering effects; and 3) to determine if central or peripheral arterial distensibility improved with IHG or ILP. The population examined was people whom were medicated for hypertension.</p> <p> RBP, as assessed by brachial oscillometry, and arterial distensibility, as assessed by Doppler ultrasound and applanation tonometry in the carotid, brachial and femoral arteries, were measured pre training, after 4 weeks of training, and post training. Participants performed unilateral IHG exercise (n=10) or ILP exercise (n=9) 3 times/week for 8 weeks at 30% MVC or acted as a non-exercising control group (n=5).</p> <p> Results indicated that the present study was unable to reproduce the RBP reductions noted in previous studies using IHG exercise. Also, the ILP exercise group did not experience reductions in RBP. Finally, neither central nor peripheral arterial distensibility improved in the IHG or ILP group when compared to the control group.</p> <p> Although these findings are contrary to our hypotheses one must consider that the control group examined contained very few subjects. This may have limited our ability to detect statistically significant changes in RBP and arterial distensibility.</p> / Thesis / Master of Science (MSc)

EINLEITUNG: Die „Hypertension and Diabetes Risk Screening and Awareness (HYDRA-)-Studie“ beschrieb und quantifizierte erstmals umfassend und bundesweit in einer Reihe von Publikationen1- 10 (siehe auch www.hydra-studie.de) die hausärztliche Versorgungssituation von Patienten mit arterieller Hypertonie und Diabetes mellitus. Mit Hilfe dieser Studie konnten neue Erkenntnisse zur Häufigkeit und Schwere, zu häufigen Begleit- oder Folgeerkrankungen, sowie zur Therapie dieser beiden Erkrankungen gewonnen werden. Insgesamt wurden im September 2001 in einer bundesrepräsentativen Stichprobe von 1.912 zufällig ausgewählten primärärztlichen Praxen (auf der Grundlage des IMS-Registers, Instituts für Medizinische Statistik, Frankfurt) eine Stichtagsbefragung von 45125 nicht-selektierter, konsekutiver Patienten ab dem 16. Lebensjahr durchgeführt (60,0 Prozent Frauen; Altersgruppen: 12,7 Prozent 16 bis 29 Jahre, 21,9 Prozent 30 bis 44 Jahre, 23,2 Prozent: 45 bis 59 Jahre, 42,2 Prozent: = 60 Jahre) und ihre Erkrankungen und Interventionen dokumentiert. Im folgenden Beitrag sollen die Ergebnisse für Sachsen gesondert berichtet und den bundesdeutschen Ergebnissen gegenübergestellt werden. In Sachsen nahmen an der HYDRA-Studie n=126 Ärzte teil, die an zwei aufeinander folgenden Studientagen insgesamt 2.407 Patienten dokumentierten. Die Datenerhebung erfolgte im Rahmen eines klinischepidemiologischen Stufendesigns: (i) Zunächst wurden die teilnehmenden Ärzte in einer Voruntersuchung hinsichtlich ihrer Ausbildungsund Praxismerkmale, ihren Erfahrungen und Problemen mit Hypertonikern und Diabetikern sowie ihren Einstellungen zu diesen Patientengruppen befragt. (ii) Am Erhebungstag wurden alle Patienten, die die teilnehmenden Praxen aufsuchten, ausführlich zu ihren Beschwerden, Krankheiten sowie zu ihrem Gesundheitsverhalten befragt (Patientenfragebogen). (iii) Die Ärzte dokumentierten dann für jeden Patienten die von ihnen vergebenen klinischen Diagnosen sowie die Therapie (Arztbogen); zudem wurden ausgewählte Messwerte am Studientag erfasst (Blutdruck, Mikroalbuminurie mit Micral-Teststreifen) und weitere Laborwerte aus der Akte entnommen. Für die ärztlichen Diagnosen wurden keine Vorgaben (zum Beispiel Nennung von Grenzwerten) gemacht. Die Methodik der Studie und wesentliche Ergebnisse wurden in einer Reihe von Originalarbeiten detailliert beschrieben.5