Postaerobic Exercise Blood Pressure Reduction in Very Old Persons With Hypertension.

BACKGROUND AND PURPOSE: A single bout of aerobic exercise acutely decreases blood pressure, even in older adults with hypertension. Nonetheless, blood pressure responses to aerobic exercise in very old adults with hypertension have not yet been documented. Therefore, this study aimed to assess the effect of a single session of aerobic exercise on postexercise blood pressure in very old adults with hypertension. METHODS: Eighteen older adults with essential hypertension were randomized into exercise (N = 9, age: 83.4 ± 3.2 years old) or control (N = 9, age: 82.7 ± 2.5 years old) groups. The exercise group performed a session of aerobic exercise constituting 2 periods of 10 minutes of walking at an intensity of 40% to 60% of the heart rate reserve. The control group rested for the same period of time. Anthropometric variables and medication status were evaluated at baseline. Heart rate and systolic and diastolic blood pressures were measured at baseline, after exercise, and at 20 and 40 minutes postexercise. RESULTS: Systolic blood pressure showed a significant interaction for group × time (F3,24 = 6.698; P = .002; ηp = 0.153). In the exercise group, the systolic blood pressure at 20 (127.3 ± 20.9 mm Hg) and 40 minutes (123.7 ± 21.0 mm Hg) postexercise was significantly lower in comparison with baseline (135.6 ± 20.6 mm Hg). Diastolic blood pressure did not change. Heart rate was significantly higher after the exercise session. In the control group, no significant differences were observed. CONCLUSIONS: A single session of aerobic exercise acutely reduces blood pressure in very old adults with hypertension and may be considered an important nonpharmacological strategy to control hypertension in this age group.

Parallel programming in biomedical signal processing

Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica

Tilt Training Increases Vasoconstrictor Reserve in Patients with Neurocardiogenic Syncope

Neurocardiogenic syncope (NCS) is a common clinical entity resulting from an excessive reflex autonomic response, particularly during orthostatism. Treatment options are controversial and of limited effectiveness. Tilt training (TT) is a promising option to treat these patients. However, its mechanism of action and clinical impact remain unclear. OBJECTIVE: To characterize hemodynamic and autonomic responses during a TT program in patients with NCS refractory to conventional measures. METHODS: We studied 28 patients (50% male, mean age 41±14 years) without structural heart disease, with NCS documented by tilt testing. The TT program included 9 tilt sessions (3 times a week, 30 min) (60° - 6 sessions, 70° - 3 sessions), under ECG and blood pressure monitoring combined with home orthostatic self-training and 10° head-up during sleep. Systolic volume, cardiac output, total peripheral resistance, baroreflex sensitivity and heart-rate variability were computed. Patients were reassessed at 1 month and every 6 months for a maximum of 36 months (24±12 months). RESULTS: Over the course of the TT program there was a significant increase in total peripheral resistance (1485±225 vs. 1591±187 dyn·s·cm(-5), p<0.05), with a decrease in standard deviation (206±60 vs. 150±42, p<0.05). During follow-up, syncope recurred in five patients (19%), with a significant reduction in the number of episodes (4.0±3.2/patient in the 12 months before TT vs. 1.4±0.8/patient post-TT, p<0.05). CONCLUSION: In refractory NCS, TT may be an effective therapeutic option, with long-term benefits. These results appear to be due to an increase in vasoconstrictor reserve combined with a reduction in its variance.

Biological and Physiological Markers of Tactile Sensorial Processing in Healthy Newborns

The main objective of this review is to provide a descriptive analysis of the biological and physiological markers of tactile sensorial processing in healthy, full-term newborns. Research articles were selected according to the following study design criteria: (a) tactile stimulation for touch sense as an independent variable; (b) having at least one biological or physiological variable as a dependent variable; and (c) the group of participants were characterized as full-term and healthy newborns; a mixed group of full-term newborns and preterm newborns; or premature newborns with appropriate-weight-for-gestational age and without clinical differences or considered to have a normal, healthy somatosensory system. Studies were then grouped according to the dependent variable type, and only those that met the aforementioned three major criteria were described. Cortisol level, growth measures, and urinary catecholamine, serotonin, and melatonin levels were reported as biological-marker candidates for tactile sensorial processing. Heart rate, body temperature, skin-conductance activity, and vagal reactivity were described as neurovegetative-marker candidates. Somatosensory evoked potentials, somatosensory evoked magnetic fields, and functional neuroimaging data also were included.

Clinical and laboratory findings related to a favorable evolution of hantavirus pulmonary syndrome

The medical records of 27 patients with hantavirus pulmonary syndrome were analyzed according to the need for invasive mechanical ventilation in relation to the following data up on hospital admission: age, gender, fever, cough, dyspnea, systolic arterial blood pressure, heart rate, levels of hemoglobin, hematocrit, leukocytes, lymphocytes, platelets, creatinine and arterial blood gases. The volume infused during the first 24 hours after admission, the use of inotropic agents, the use of corticosteroids and the patient outcomes were also evaluated. A favorable outcome was related to systolic blood pressure³ 100mmHg, heart rate lower than 100 beats per minute, creatinine below 1.6mg/dl, arterial blood pH³ 7.35, bicarbonate higher than 15mEq/dl, oxygen saturation higher than 84.1%, lower rehydration volume in the first 24 hours of hospitalization and no use of inotropic agents. Absence of clinical and laboratory signs of circulatory shock up on admission was associated with a favorable outcome of the patients.

Insights into the clinical and functional significance of cardiac autonomic dysfunction in Chagas disease

INTRODUCTION: Exclusive or associated lesions in various structures of the autonomic nervous system occur in the chronic forms of Chagas disease. In the indeterminate form, the lesions are absent or mild, whereas in the exclusive or combined heart and digestive disease forms, they are often more pronounced. Depending on their severity these lesions can result mainly in cardiac parasympathetic dysfunction but also in sympathetic dysfunction of variable degrees. Despite the key autonomic effect on cardiovascular functioning, the pathophysiological and clinical significance of the cardiac autonomic dysfunction in Chagas disease remains unknown. METHODS: Review of data on the cardiac autonomic dysfunction in Chagas disease and their potential consequences, and considerations supporting the possible relationship between this disturbance and general or cardiovascular clinical and functional adverse outcomes. RESULTS: We hypothesise that possible consequences that cardiac dysautonomia might variably occasion or predispose in Chagas disease include: transient or sustained arrhythmias, sudden cardiac death, adverse overall and cardiovascular prognosis with enhanced morbidity and mortality, an inability of the cardiovascular system to adjust to functional demands and/or respond to internal or external stimuli by adjusting heart rate and other hemodynamic variables, and immunomodulatory and cognitive disturbances. CONCLUSIONS: Impaired cardiac autonomic modulation in Chagas disease might not be a mere epiphenomenon without significance. Indirect evidences point for a likely important role of this alteration as a primary predisposing or triggering cause or mediator favouring the development of subtle or evident secondary cardiovascular functional disturbances and clinical consequences, and influencing adverse outcomes.

Evaluation of antihypertensive drugs in patients with obstructive sleep apnea and in rats submitted to chronic intermittent hypoxia

RESUMO: A hipertensão arterial (HA) é uma patologia altamente prevalente, embora claramente subdiagnosticada, em doentes com síndrome de apneia obstrutiva do sono (SAOS). Estas duas patologias apresentam uma estreita relação e a monitorização ambulatória da pressão arterial (MAPA), por um período de 24 horas, parece ser o método mais preciso para o diagnóstico de hipertensão em doentes com SAOS. No entanto, esta ferramenta de diagnóstico para além de ser dispendiosa e envolver um número acrescido de meios técnicos e humanos, é mais morosa e, por conseguinte, não é utilizada por rotina no contexto do diagnóstico da SAOS. Por outro lado, apesar da aplicação de pressão positiva contínua nas vias aéreas (CPAP – Continous Positive Airway Pressure) ser considerada a terapêutica de eleição para os doentes com SAOS, o seu efeito no abaixamento da pressão arterial (PA) parece ser modesto, exigindo, por conseguinte, a implementação concomitante de terapêutica anti-hipertensora. Acontece que são escassos os dados relativos aos regimes de fármacos anti-hipertensores utilizados em doentes com SAOS e, acresce ainda que, as guidelines terapêuticas para o tratamento farmacológico da HA, neste grupo particular de doentes, permanecem, até ao momento, inexistentes. A utilização de modelos animais de hipóxia crónica intermitente (CIH), que mimetizam a HA observada em doentes com SAOS, revela-se extremamente importante, uma vez que se torna imperativo identificar fármacos que promovam um controle adequado da PA neste grupo de doentes. No entanto, estudos concebidos com o intuito de investigar o efeito anti-hipertensor dos fármacos neste modelo animal revelam-se insuficientes e, por outro lado, os escassos estudos que testaram fármacos anti-hipertensores neste modelo não foram desenhados para responder a questões de natureza farmacológica. Acresce ainda que se torna imprescindível garantir a escolha de um método para administração destes fármacos que seja não invasivo e que minimize o stress do animal. Embora a gavagem seja uma técnica indiscutivelmente eficaz e amplamente utilizada para a administração diária de fármacos a animais de laboratório, ela compreende uma sequência de procedimentos geradores de stress para os animais e, que podem por conseguinte, constituir um viés na interpretação dos resultados obtidos. O objectivo global da presente investigação translacional foi contribuir para a identificação de fármacos anti-hipertensores mais efectivos para o tratamento da HT nos indivíduos com SAOS e investigar mecanismos subjacentes aos efeitos sistémicos associadas à SAOS bem como a sua modulação por fármacos anti-hipertensores. Os objectivos específicos foram: em primeiro lugar,encontrar novos critérios, baseados nas medidas antropométricas, que permitam a identificação de doentes com suspeita de SAOS, que erroneamente se auto-classifiquem como nãohipertensos, e desta forma promover um uso mais criterioso do MAPA; em segundo lugar, investigar a existência de uma hipotética associação entre os esquemas de fármacos antihipertensores e o controle da PA (antes e após a adaptação de CPAP) em doentes com SAOS em terceiro lugar, avaliar a eficácia do carvedilol (CVD), um fármaco bloqueador β-adrenérgico não selectivo com actividade antagonista α1 intrínseca e propriedades anti-oxidantes num modelo animal de hipertensão induzida pela CIH; em quarto lugar, explorar os efeitos da CIH sobre o perfil farmacocinético do CVD; e, em quinto lugar, investigar um método alternativo à gavagem para a administração crónica de fármacos anti-hipertensores a animais de laboratório. Com este intuito, na primeira fase deste projecto, fizemos uso de uma amostra com um número apreciável de doentes com SAOS (n=369), que acorreram, pela primeira vez, à consulta de Patologia do Sono do CHLN e que foram submetidos a um estudo polissonográfico do sono, à MAPA e que preencheram um questionário que contemplava a obtenção de informação relativa ao perfil da medicação anti-hipertensora em curso. Numa segunda fase, utilizámos um modelo experimental de HT no rato induzida por um paradigma de CIH. Do nosso trabalho resultaram os seguintes resultados principais: em primeiro lugar, o índice de massa corporal (IMC) e o perímetro do pescoço (PP) foram identificados como preditores independentes de “auto-classificação errónea” da HA em doentes com suspeita de SAOS; em segundo lugar, não encontramos qualquer associação com significado estatístico entre os vários esquemas de fármacos anti-hipertensores bem como o número de fármacos incluídos nesse esquemas, e o controle da PA (antes e depois da adaptação do CPAP); em terceiro lugar, apesar das doses de 10, 30 e 50 mg/kg de carvedilol terem promovido uma redução significativa da frequência cardíaca, não foi observado qualquer decréscimo na PA no nosso modelo animal; em quarto lugar, as razões S/(R+S) dos enantiómeros do CVD nos animais expostos à CIH e a condições de normóxia revelaram-se diferentes; e, em quinto lugar, a administração oral voluntária mostrou ser um método eficaz para a administração diária controlada de fármacos anti-hipertensores e que é independente da manipulação e contenção do animal. Em conclusão, os resultados obtidos através do estudo clínico revelaram que o controle da PA, antes e após a adaptação do CPAP, em doentes com SAOS é independente, quer do esquema de fármacos anti-hipertensores, quer do número de fármacos incluídos num determinado esquema. Os nossos resultados salientam ainda a falta de validade da chamada self-reported hypertension e sugerem que em todos os doentes com suspeita de SAOS, com HA não diagnosticada e com um IMC e um PP acima de 27 kg/m2 e 39 cm, respectivamente, a confirmação do diagnóstico de HA deverá ser realizada através da MAPA, ao invés de outros métodos que com maior frequência são utilizados com este propósito. Os resultados obtidos no modelo animal de HA induzida pela CIH sugerem que o bloqueio do sistema nervoso simpático, juntamente com os supostos efeitos pleiotrópicos do CVD, não parece ser a estratégia mais adequada para reverter este tipo particular de hipertensão e indicam que as alterações farmacocinéticas induzidas pela CIH no ratio S/(R+S) não justificam a falta de eficácia anti-hipertensora do CVD observada neste modelo animal. Por último, os resultados do presente trabalho suportam ainda a viabilidade da utilização da administração oral voluntária, em alternativa à gavagem, para a administração crónica de uma dose fixa de fármacos anti-hipertensores.---------------------------- ABSTRACT: Hypertension (HT) is a highly prevalent condition, although under diagnosed, in patients with obstructive sleep apnea (OSA). These conditions are closely related and 24-hour ambulatory blood pressure monitoring (ABPM) seems to be the most accurate measurement for diagnosing hypertension in OSA. However, this diagnostic tool is expensive and time-consuming and, therefore, not routinely used. On the other hand, although continuous positive airway pressure (CPAP) is considered the gold standard treatment for symptomatic OSA, its lowering effect on blood pressure (BP) seems to be modest and, therefore, concomitant antihypertensive therapy is still required. Data on antihypertensive drug regimens in patients with OSA are scarce and specific therapeutic guidelines for the pharmacological treatment of hypertension in these patients remain absent. The use of animal models of CIH, which mimic the HT observed in patients with OSA, is extremely important since it is imperative to identify preferred compounds for an adequate BP control in this group of patients. However, studies aimed at investigating the antihypertensive effect of antihypertensive drugs in this animal model are insufficient, and most reports on CIH animal models in which drugs have been tested were not designed to respond to pharmacological issues. Moreover, when testing antihypertensive drugs (AHDs) it becomes crucial to ensure the selection of a non-invasive and stress-free method for drug delivery. Although gavage is effective and a widely performed technique for daily dosing in laboratory rodents, it comprises a sequence of potentially stressful procedures for laboratory animals that may constitute bias for the experimental results. The overall goal of the present translational research was to contribute to identify more effective AHDs for the treatment of hypertension in patients with OSA and investigate underlying mechanisms of systemic effects associated with OSA, as well as its modulation by AHDs. The specific aims were: first, to find new predictors based on anthropometric measures to identify patients that misclassify themselves as non-hypertensive, and thereby promote the selective use of ABPM; second, to investigate a hypothetical association between ongoing antihypertensive regimens and BP control rates in patients with OSA, before and after CPAP adaptation; third, to determine, in a rat model of CIH-induced hypertension, the efficacy of carvedilol (CVD), a nonselective beta-blocker with intrinsic anti-α1-adrenergic activity and antioxidant properties; fourth, to explore the effects of CIH on the pharmacokinetics profile of CVD and fifth, to investigate an alternative method to gavage, for chronic administration of AHDs to laboratory rats. For that, in the first phase of this project, we used a sizeable sample of patients with OSA (n=369), that attended a first visit at Centro Hospitalar Lisboa Norte, EPE Sleep Unit, and underwent overnight polysomnography, 24-h ABPM and filled a questionnaire that included ongoing antihypertensive medication profile registration. In the second phase, a rat experimental model of HT induced by a paradigm of CIH that simulates OSA was used. The main findings of this work were: first, body mass index (BMI) and neck circumference (NC) were identified as independent predictors of hypertension misclassification in patients suspected of OSA; second, in patients with OSA, BP control is independent of both the antihypertensive regimen and the number of antihypertensive drugs, either before or after CPAP adaptation; third, although the doses of 10, 30 and 50 mg/Kg of CVD promoted a significant reduction in heart rate, no decrease in mean arterial pressure was observed; fourth, the S/(R+S) ratios of CVD enantiomers, between rats exposed to CIH and normoxic conditions, were different and fifth, voluntary ingestion proved to be an effective method for a controlled daily dose administration, with a define timetable, that is independent of handling and restraint procedures. In conclusion, the clinical study showed that BP control in OSA patients is independent of both the antihypertensive regimen and the number of antihypertensive drugs. Additionally, our results highlight the lack of validity of self-reported hypertension and suggest that all patients suspected of OSA with undiagnosed hypertension and with a BMI and NC above 27 Kg/m2 and 39 cm should be screened for hypertension, through ABPM. The results attained in the rat model of HT related to CIH suggest that the blockade of the sympathetic nervous system together with the putative pleiotropic effects of carvedilol is not able to revert hypertension induced by CIH and point out that the pharmacokinetic changes induced by CIH on S/(R+S) ratio are not apparently responsible for the lack of efficacy of carvedilol in reversing this particular type of hypertension. Finally, the results here presented support the use of voluntary oral administration as a viable alternative to gavage for chronic administration of a fixed dose of AHDs.

Evaluation of efficacy, reliability, and tolerability of sibutramine in obese patients, with an echocardiographic study

This is a double-blind, placebo-controlled study of the efficacy, safety, and tolerability of sibutramine in the management of obese patients for a 6-month period. METHOD: Sixty-one obese patients (BMI >30, <40 kg/m2), aged 18-65 years were evaluated. In the first phase of the study (30 days), the patients were given a placebo. We monitored compliance with a low-calorie diet (1200 kcal/day) and to the placebo. In the next stage, the double-blind phase (6 months), we compared placebo and sibutramine (10 mg/day). The criteria for evaluating efficacy were weight loss, reduction in body mass index (BMI), and abdominal and hip circumferences. Tolerability was assessed based on reported side effects, variation in arterial blood pressure and heart rate, metabolic profile (fasting glucose, total cholesterol and its fractions, and triglycerides), laboratory tests (renal and hepatic functions), and flow Doppler echocardiogram. RESULTS: We observed a greater weight loss (7.3 kg, 8% vs 2.6 kg, 2.8%) and a reduction in body mass index (7.4% vs 2.1%) in the sibutramine group than in the placebo group. Classifying the patients into 4 subgroups according to weight loss (weight gain, loss <5%, loss of 5% to 9.9%, and loss >10%), we observed a weight loss of >5% in 40% of the patients on sibutramine compared with 12.9% in the placebo group. We also detected weight gain in 45.2% of the placebo group compared to 20% in the sibutramine group. The sibutramine group showed improvement in HDL- cholesterol values (increased by 17%) and triglyceride values (decreased by 12.8%). This group also showed an increase in systolic blood pressure (6.7%, 5 mmHg). There were no changes in echocardiograms comparing the beginning and end of follow-up, and side effects did not lead to discontinuation of treatment. DISCUSSION: Sibutramine proved to be effective for weight loss providing an 8% loss of the initial weight. Compliance to prolonged treatment was good, and side effects did not result in discontinuation of treatment. These data confirmed the good efficacy, tolerability, and safety profiles of sibutramine for treatment of obesity.

Cholinergic stimulation with pyridostigmine, hemodynamic and echocardiographic analysis in healthy subjects

OBJECTIVE: Growing evidence suggests that sudden death after an acute myocardial infarction (AMI) correlates with autonomic nervous system imbalance. Parasympathomimetic drugs have been tested to reverse these changes. However, their effects on ventricular function need specific evaluation. Our objective was to analyze pyridostigmine's (PYR) effect on hemodynamic and echocardiographic variables of ventricular function. METHODS: Twenty healthy volunteers underwent Doppler echocardiographic evaluations, blood pressure (BP), and heart rate (HR) assessment at rest, before and 120 min after ingestion of 30 mg PYR or placebo, according to a double-blind, placebo-controlled, crossed and randomized protocol, on different days. RESULTS: PYR was well tolerated and did not cause alterations in BP or in ventricular systolic function. A reduction in HR of 10.9±1.3% occurred (p<0,00001). There was an A wave reduction in the mitral flow (p<0.01) and an E/A ratio increase (p<0.001) without changes in the other diastolic function parameters (p>0.05). CONCLUSION: PYR reduces HR and increases E/A ratio, without hemodynamic impairment or ventricular function change.

Influence of the elevation of the left ventricular diastolic pressure on the values of the first temporal derivative of the ventricular pressure (dP/dt)

PURPOSE: To assess the effects of the elevation of the left ventricular end-diastolic pressure (LVEDP) on the value of the 1st temporal derivative of the ventricular pressure (dP/dt). METHODS: Nineteen anesthetized dogs were studied. The dogs were mechanically ventilated and underwent thoracotomy with parasympathetic nervous system block. The LVEDP was controlled with the use of a perfusion circuit connected to the left atrium and adjusted to the height of a reservoir. The elevation of the LVEDP was achieved by a sudden increase in the height of a reservoir filled with blood. Continuous recordings of the electrocardiogram, the aortic and ventricular pressures and the dP/dt were performed. RESULTS: Elevation of the LVEDP did not result in any variation of the heart rate (167±16.0bpm, before the procedure; 167±15.5bpm, after the procedure). All the other variables assessed, including systolic blood pressure (128±18.3mmHg and 150±21.5mmHg), diastolic blood pressure (98±16.9mmHg and 115±19.8mmHg), LVEDP (5.5±2.49 and 9.3±3.60mmHg), and dP/dt (4,855 ± 1,082 mmHg/s and 5,149±1,242mmHg/s) showed significant increases following the expansion of the ventricular cavity. Although the elevation of the dP/dt was statistically significant, 6 dogs curiously showed a decrease in the values of dP/dt. CONCLUSION: Sudden elevation of the LVEDP resulted in increased values of dP/dt; however, in some dogs, this response was not uniform.

Results of the surgical treatment of chronic atrial fibrillation

OBJECTIVE: Report clinical experience in surgical treatment of atrial fibrillation (AF) by Cox-maze procedure. METHODS: 61 patients underwent surgical treatment for AF. Two had primary AF and 59 AF secondary to heart disease (2 atrial septal defects, 57 mitral). Ages ranged from 20 to 74 years (mean = 49). There were 44 females (72%). The surgical technique employed was Cox 3 without cryoablation. The patients were follow-up in specific at patient clinics and underwent periodical ECG, exercise tests, echocardiogram and Holter monitoring. RESULTS: In-hospital mortality was 4.9% and late mortality 1.6%. A temporary pacemaker was used in 28 (46%) and a definitive in 7 patients (11.4%). On hospital discharge, AF remained in 17%; 63.9% had sinus rhythm, 6.9% atrial rhythm, 1.7% junctional rhythm, and 10.3% had pacemaker rhythm. In the last evaluation, AF was present in 19.5%; (70.5% sinus rhythm, 4% atrial rhythm, 2% atrial tachycardia, and 4% pacemaker rhythm). There was no report of thromboembolic episodes. Chronotropic response was considered adequate in 19%, intermediate in 29%, and inadequate in 42%. In Holter monitoring, the mean heart rate was 82±8 bpm, with a minimum of 57±7 bpm and maximum of 126±23 bpm, with supraventricular extrasystoles in 2.3±5.5% of the total heartbeats and ventricular extrasystoles in 0.8±0.5%. In the echocardiogram, the A wave was present in the left atrium in 87.5%. CONCLUSION: Maze procedure is effective and has acceptable surgical risk. Atrial or sinus rhythms remain stable with a small but remarkable frequency of atrial and ventricular arrhythmias. Left atrial contraction is present, although attenuated, as well as the chronotropic response to exercise.

Exercise stress testing in healthy subjects during cholinergic stimulation after a single dose of pyridostigmine

OBJETIVE: The evaluation, by exercise stress testing, of the cardiorespiratory effects of pyridostigmine (PYR), a reversible acetylcholinesterase inhibitor. METHODS: A double-blind, randomized, cross-over, placebo-controlled comparison of hemodynamic and ventilation variables of 10 healthy subjects who underwent three exercise stress tests (the first for adaptation and determination of tolerance to exercise, the other two after administration of placebo or 45mg of PYR). RESULTS: Heart rate at rest was: 68±3 vs 68±3bpm before and after placebo, respectively (P=0.38); 70±2 vs 59±2bpm, before and after pyridostigmine, respectively (P<0.01). During exercise, relative to placebo: a significantly lower heart rate after PYR at, respectively, 20% (P=0.02), 40% (P=0.03), 80% (P=0.05) and 100% (P=0.02) of peak effort was observed. No significant differences were observed in arterial blood pressure, oxygen consumption at submaximal and maximal effort, exercise duration, respiratory ratio, CO2 production, ventilation threshold, minute ventilation, and oxygen pulse. CONCLUSION: Pyridostigmine, at a dose of 45mg, decreases heart rate at rest and during exercise, with minimal side effects and without interfering with exercise tolerance and ventilation variables.

Acute Effects of Maternal Smoking on Fetal-Placental-Maternal System Hemodynamics

OBJECTIVE: To study acute hemodynamic alterations in the fetal-placental maternal system immediately after maternal exposure to nicotine. METHODS: This is a noncontrolled experimental study involving 21 pregnant smoking women, randomly selected, with uncomplicated pregnancies and without risk factors for fetal heart disease. Patients underwent ultrasound and fetal echocardiography before and after smoking a cigarette. They were asked to abstain from smoking for 12 hours before the study. The mean nicotine content of the cigarettes used in the study was 0.5mg of nicotine and 6mg of carbon monoxide. RESULTS: The average number of cigarettes smoked per a day prior to the study was 9.67. Gestational age ranged between 18 and 36 weeks. The mean maternal heart rate was elevated (P<0.001) as was the mean fetal heart rate (P=0.044). Maternal systolic blood pressure (P=0.004) and diastolic blood pressure (P=0.033) were also elevated after smoking. A decrease occurred in the systolic/diastolic ratio in the right uterine artery (P=0.014) and in the left uterine artery (P=0.039). The other hemodynamic variables remained unchanged. CONCLUSION: Cigarette smoking can cause changes in physiologic variables of fetal-placental circulation, but it does not change fetal cardiac function, in the dose of nicotine and its components used in this study. The decrease in systolic/diastolic ratio in the uterine arteries is probably related to a dose-dependent nicotine pattern.

Effects of Sibutramine on the Treatment of Obesity in Patients with Arterial Hypertension

OBJECTIVE: To assess the effects of weight reduction with 10mg of sibutramine or placebo on blood pressure during 24 hours (ambulatory blood pressure monitoring), on left ventricular mass, and on antihypertensive therapy in 86 obese and hypertensive patients for 6 months. METHODS: The patients underwent echocardiography, ambulatory blood pressure monitoring, and measurement of the levels of hepatic enzymes prior to and after treatment with sibutramine or placebo. RESULTS: The group using sibutramine had a greater weight loss than that using placebo (6.7% versus 2.5%; p<0.001), an increase in heart rate (78.3±7.3 to 82±7.9 bpm; p=0.02), and a reduction in the left ventricular mass/height index (105±29.3 versus 96.6±28.58 g/m; p=0.002). Both groups showed similar increases in the levels of alkaline phosphatase and comparable adjustments in antihypertensive therapy; blood pressure, however, did not change. CONCLUSION: The use of sibutramine caused weight loss and a reduction in left ventricular mass in obese and hypertensive patients with no interference with blood pressure or with antihypertensive therapy.