High-dose Chemotherapy Impairs Cardiac Autonomic Control of Hospitalized Cancer Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation.

BACKGROUND: Autologous hematopoietic stem cell transplantation (HSCT) patients have intermediary and late cardiac autonomic dysfunction, which is an independent mortality predictor. However, it is unknown when this HSCT-related autonomic dysfunction begins during hospitalization for HSCT and whether cardiac autonomic control (CAC) is related to cardiotoxicity in these patients. PATIENTS AND METHODS: CAC was assessed in 36 autologous-HSCT inpatients (HSCT group) and 23 cancer-free outpatients (CON group) using heart rate variability analysis. The HSCT group was assessed at five time-points from admission to hospital discharge during hospitalization period. The CON group was assessed once. The severity of cardiotoxicity (CTCAE 5.0) and cardiac troponin I were recorded. RESULTS: The CAC was significantly reduced after high-dose chemotherapy (HDC) (reduction of MNN, SDNN, RMSSD, LFms2 and HFnu, and increase of LFnu and LF/HF; P<0.05). At the onset of neutropenia, pNN50 and HFms2 were also reduced (P<0.05) compared to the admission ones. Although both groups were similar regarding CAC at hospital admission, the HSCT patients showed impaired CAC at hospital discharge (P<0.05). The LF/HF was positively associated with cardiac troponin I and RMSSD was inversely associated with the severity of cardiotoxicity (P≤0.05). CONCLUSION: CAC worsened during hospitalization for autologous-HSCT, mainly after HDC. In addition, it seems associated to early signs of cardiotoxicity in these patients.

Inspiratory muscle training in addition to conventional physical rehabilitation in hospitalized patients undergoing hematopoietic stem cell transplantation: a randomized controlled trial.

PURPOSE: To investigate the effect of inspiratory muscle training (IMT) in addition to conventional physical rehabilitation on muscle strength, functional capacity, mobility, hemodynamics, fatigue, and quality of life in hospitalized patients undergoing hematopoietic stem cell transplantation (HSCT). METHODS: We conducted a randomized controlled trial in 57 inpatients with hematological diseases undergoing HSCT. Conventional inpatient physical rehabilitation was delivered to the IMT (n = 27) and control (CON; n = 30) groups according to usual care, and the first group additionally performed IMT. The IMT was prescribed according to clinical and laboratory parameters at 40% of maximal inspiratory pressure (MIP), 5 days/week throughout the hospitalization, in sessions of 10-20 min. The primary outcome was MIP and the secondary outcomes were maximal expiratory pressure (MEP), peripheral muscle strength (handgrip and sit-to-stand tests), functional capacity (6-min step test), mobility (timed up and go test), blood pressure, quality of life (EORTC-QLQ-C30), and fatigue (FACT-F) at admission and hospital discharge. RESULTS: The population was predominately autologous HSCT. The IMT group significantly increased the MIP (P < 0.01) and decreased both fatigue (P = 0.01) and blood pressure (P < 0.01) compared with control. No differences were found between admission and hospital discharge in peripheral and expiratory muscle strength, functional capacity, mobility, and quality of life in both groups (P > 0.05). CONCLUSIONS: Our results support the effectiveness of IMT as part of rehabilitation for HSCT inpatients, improving inspiratory muscle strength, and reducing fatigue and blood pressure. TRIAL REGISTRATION: NCT03373526 (clinicaltrials.gov).

Neurovascular Control and Cardiac Structure in Amateur Runners with Hypertension.

PURPOSE: The neurovascular mechanisms underlying hypertension are minimized by exercise training. However, it is not known whether previously trained individuals with hypertension would have deleterious repercussion of this disease. Our aim was to investigate the neurovascular control and the cardiac structure of athletes with hypertension. METHODS: Muscle sympathetic nerve activity (MSNA) (microneurography), baroreflex sensitivity (intravenous infusion of phenylephrine and nitroprusside), arterial stiffness (pulse wave velocity and echotracking), and cardiac structure (echocardiography) were evaluated in 17 runners with hypertension (42 ± 1 yr) and 20 normotensive (43 ± 1 yr) amateur runners. RESULTS: Runners with hypertension had higher MSNA (+24% burst frequency, P = 0.02; +24%, burst incidence, P < 0.01), left ventricular mass (+22%, P < 0.01), septum wall thickness (+9%, P = 0.04), posterior wall thickness (+11%, P = 0.04), and left atrium (+11%, P < 0.001) compared with normotensive runners. Baroreflex control of heart rate was lower in runners with hypertension during increase (P = 0.05) but not during decrease (P = 0.11) of systolic blood pressure when compared with normotensive runners. There was no difference between groups in baroreflex control of MSNA during increase (P = 0.38) and decrease (P = 0.36) of diastolic blood pressure. Pulse wave velocity (P = 0.71) and carotid variables: intima media thickness (P = 0.18), diameter (P = 0.09), and distension (P = 0.79) were similar between groups. CONCLUSIONS: Sympathetic overactivity seems to be involved in the underlying mechanisms of hypertension in amateur runners. Alterations in cardiac structure and decreased baroreflex control of heart rate suggest limited protection from exercise training. However, baroreflex control of MSNA and elastic properties of artery are preserved in this population.

Exercise-induced muscle vasodilatation and treadmill exercise test responses in individuals without overt heart disease.

BACKGROUND: The beneficial effects of exercise on cardiovascular health may be related to the improvement in several physiologic pathways, including peripheral vascular function. The aim of this study was to evaluate the relationship between cardiovascular responses during the treadmill exercise test and exercise-induced muscle vasodilatation in individuals without overt heart disease. METHODS: The study included 796 asymptomatic subjects (431 females and 365 males) without overt heart disease. We evaluated the heart rate (chronotropic reserve and heart rate recovery), blood pressure (maximum systolic and diastolic blood pressure as well as systolic blood pressure recovery) and exercise capacity during symptom-limited treadmill exercise testing. Exercise-induced muscle vasodilatation was studied with venous occlusion plethysmography and estimated by forearm blood flow and vascular conductance responses during a 3-min handgrip maneuver. RESULTS: Forearm blood flow increase during the handgrip exercise was positively associated with heart rate recovery during treadmill exercise testing (p < 0.001). Forearm vascular conductance increase during the handgrip exercise was inversely associated with exercise diastolic blood pressure during exercise treadmill testing (p = 0.038). No significant association was found between exercise capacity and exercise-induced muscle vasodilation. CONCLUSION: In a sample of individuals without overt heart disease, exercise-induced muscle vasodilatation was associated with heart rate and blood pressure responses during treadmill exercise testing, but was not associated with exercise capacity. These findings suggest that favorable hemodynamic and chronotropic responses are associated with better vasodilator capacity, but exercise capacity does not predict muscle vasodilatation.

Burnt sugarcane harvesting - cardiovascular effects on a group of healthy workers, Brazil.

BACKGROUND: Brazil is the world's largest producer of sugarcane. Harvest is predominantly manual, exposing workers to health risks: intense physical exertion, heat, pollutants from sugarcane burning. DESIGN: Panel study to evaluate the effects of burnt sugarcane harvesting on blood markers and on cardiovascular system. METHODS: Twenty-eight healthy male workers, living in the countryside of Brazil were submitted to blood markers, blood pressure, heart rate variability, cardiopulmonary exercise testing, sympathetic nerve activity evaluation and forearm blood flow measures (venous occlusion plethysmography) during burnt sugarcane harvesting and four months later while they performed other activities in sugar cane culture. RESULTS: Mean participant age was 31 ± 6.3 years, and had worked for 9.8 ± 8.4 years on sugarcane work. Work during the harvest period was associated with higher serum levels of Creatine Kinase - 136.5 U/L (IQR: 108.5-216.0) vs. 104.5 U/L (IQR: 77.5-170.5), (p = 0.001); plasma Malondialdehyde-7.5 ± 1.4 µM/dl vs. 6.9 ± 1.0 µM/dl, (p = 0.058); Glutathione Peroxidase - 55.1 ± 11.8 Ug/Hb vs. 39.5 ± 9.5 Ug/Hb, (p<0.001); Glutathione Transferase- 3.4±1.3 Ug/Hb vs. 3.0 ± 1.3 Ug/Hb, (p = 0.001); and 24-hour systolic blood pressure - 120.1 ± 10.3 mmHg vs. 117.0 ± 10.0 mmHg, (p = 0.034). In cardiopulmonary exercise testing, rest-to-peak diastolic blood pressure increased by 11.12 mmHg and 5.13 mmHg in the harvest and non-harvest period, respectively. A 10 miliseconds reduction in rMSSD and a 10 burst/min increase in sympathetic nerve activity were associated to 2.2 and 1.8 mmHg rises in systolic arterial pressure, respectively. CONCLUSION: Work in burnt sugarcane harvesting was associated with changes in blood markers and higher blood pressure, which may be related to autonomic imbalance.

Abnormal neurovascular control in anabolic androgenic steroids users.

PURPOSE: Previous studies showed that anabolic androgenic steroids (AAS) increase vascular resistance and blood pressure (BP) in humans. In this study, we tested the hypotheses 1) that AAS users would have increased muscle sympathetic nerve activity (MSNA) and reduced forearm blood flow (FBF) compared with AAS nonusers and 2) that there would be an association between MSNA and 24-h BP. METHODS: Twelve AAS users aged 31 +/- 2 yr (means +/- SE) and nine age-matched AAS nonusers aged 29 +/- 2 yr participated in the study. All individuals were involved in strength training for at least 2 yr. AAS was determined by urine test (chromatography-mass spectrometry). MSNA was directly measured by microneurography technique. FBF was measured by venous occlusion plethysmography. BP monitoring consisted of measures of BP for 24 h. RESULTS: MSNA was significantly higher in AAS users than that in AAS nonusers (29 +/- 3 vs 20 +/- 1 bursts per minute, P = 0.01). FBF (1.92 +/- 0.17 vs 2.77 +/- 0.24 mL x min(-1) x 100 mL(-1), P = 0.01) and forearm vascular conductance (2.01 +/- 0.17 vs 2.86 +/- 0.31 U, P = 0.02) were significantly lower in AAS users than that in AAS nonusers. Systolic (131 +/- 4 vs 120 +/- 3 mm Hg, P = 0.001), diastolic (74 +/- 4 vs 68 +/- 3 mm Hg, P = 0.02), and mean BP (93 +/- 4 vs 86 +/- 3 mm Hg, P = 0.005) and heart rate (74 +/- 3 vs 68 +/- 3 bpm, P = 0.02) were significantly higher in AAS users when compared with AAS nonusers. Further analysis showed that there was a significant correlation between MSNA and 24-h mean BP (r = 0.75, P = 0.002). CONCLUSIONS: AAS increases MSNA and reduces muscle blood flow in young individuals. In addition, the increase in BP levels in AAS users is associated with augmented sympathetic outflow. These findings suggest that AAS increases the susceptibility for cardiovascular disease in humans.

Muscle sympathetic nervous activity in depressed patients before and after treatment with sertraline.

BACKGROUND: Sympathetic hyperactivity is one of the mechanisms involved in the increased cardiovascular risk associated with depression, and there is evidence that antidepressants decrease sympathetic activity. OBJECTIVES: We tested the following two hypotheses: patients with major depressive disorder with high scores of depressive symptoms (HMDD) have augmented muscle sympathetic nervous system activity (MSNA) at rest and during mental stress compared with patients with major depressive disorder with low scores of depressive symptoms (LMDD) and controls; sertraline decreases MSNA in depressed patients. METHODS: Ten HMDD, nine LMDD and 11 body weight-matched controls were studied. MSNA was directly measured from the peroneal nerve using microneurography for 3 min at rest and 4 min during the Stroop color word test. For the LMDD and HMDD groups, the tests were repeated after treatment with sertraline (103.3 +/- 40 mg). RESULTS: Resting MSNA was significantly higher in the HMDD [29.1 bursts/min (SE 2.9)] compared with LMDD [19.9 (1.6)] and controls [22.2 (2.0)] groups (P = 0.026 and 0.046, respectively). There was a significant positive correlation between resting MSNA and severity of depression. MSNA increased significantly and similarly during stress in all the studied groups. Sertraline significantly decreased resting MSNA in the LMDD group and MSNA during mental stress in LMDD and HMDD groups. Sertraline significantly decreased resting heart rate and heart rate response to mental stress in the HMDD group. CONCLUSION: Moderate-to-severe depression is associated with increased MSNA. Sertraline treatment reduces MSNA at rest and during mental challenge in depressed patients, which may have prognostic implications in this group.

Exercício físico regular e controle autonômico na hipertensão arterial / Regular physical exercise and autonomic control in hypertension

A hipertensão arterial é considerada um dos principais fatores de risco para a morbidade e mortalidade cardiovascular...

Spectral analysis of respiratory flow and gas concentrations / Análise espectral de fluxo e concentrações de gases respiratórios

In this research we obtained samples of human respiratory flow, oxygen concentration and carbon dioxide concentration signals from 20 healthy subjects and evaluated the average power spectral density (PSD) of these signals. For each subject,the respiratory samples were acquired in four progressive levels of exercise in a cycle ergometer. Auto regressive moving average models were designed to represent the PSD found in each phase. An average PSD of the four levels was also calculated. Results have shown that the bandwidth of O2 concentration, CO2 concentration and flow signals was 8  Hz, 7 Hz, and 15  Hz, respectively, within the dynamic range of 50  dB. The PSD curves found can be used for optimal filter design for signal enhancing in fast on-line measurement of these signals.

Nesta pesquisa foram registradas amostras dos sinais respiratórios de fluxo, concentração de oxigênio e concentração de gás carbônico em 20 voluntários saudáveis. A densidade espectral de potência (DEP) média foi então calculada. Para cada voluntário, as amostras dos sinais foram registradas em quatro intensidades progressivas de esforço físico em uma bicicleta ergométrica. Para representar a DEP encontrada em cada fase foram ajustados modelos auto-regressivos de média móvel. Uma DEP média entre as quatro intensidades também é fornecida. Os resultados mostraram que as larguras de banda dos sinais de concentração de O2, concentração de CO2 e fluxo foram 8  Hz, 7  Hz e 15  Hz, respectivamente, dentro de uma faixa dinâmica de 50  dB. As curvas de DEP encontradas podem ser usadas em projetos de filtros ótimos para equalização destes sinais em medições em tempo real.

Efeito anti-hipertensivo do exercício / The anti-hypertensive effect of exercise

A hipertensão arterial é caracterizada pela manutenção elevada dos níveis pressóricos, provocando ao longo do tempo importantes lesões em órgãos-alvo. Apesar da sua alta prevalência acometendo aproximadamente 25% da população mundial com idade acima de 18 anos, o tratamentoda hipertensão arterial ainda está longe do seu ideal. Apenas um terço dos pacientes hipertensos tratados apresenta valores de pressão arterial dentro de limites satisfatórios. Além do tratamento medicamentoso, a adoção de um estilo de vida mais saudável tem sido amplamente recomendada para prevenção e tratamento da hipertensão arterial. Dentre as medidas não-medicamentosas, envolvendo mudançasno estilo de vida, a prática regular de exercícios físicos vem sendo indicada por profissionais da saúde como um meio mais efetivo para o controle dos níveis elevados de pressão arterial. Diversos estudos relatam que o efeito do exercício físico nos níveis pressóricos é tão expressivo que uma única sessão de exercício físico aeróbio provoca reduções na pressão arterial por várias horas após sua realização. Além disso, quando realizado cronicamente, o exercício físico aeróbio é capaz de prevenir e tratar a hipertensão arterial. Desta forma, abordaremos neste artigo os efeitos agudos de uma sessão de exercício físico e crônico (de um período de treinamento físico) do exercício sobre a pressão arterial do paciente hipertenso, os mecanismos autonômicos e hemodinâmicos envolvidos na redução da pressão arterial e a orientação de exercício recomendada para o paciente hipertenso.

Efeitos hipotensores e simpatolíticos do exercício aeróbio na hipertensão arterial / Hypotensive and sympatholytic effects of aerobic exercise on hypertension

A hipertensão arterial caracteriza-se pela manutenção da pressão arterial elevada e está ligada à hiperatividade simpática. O tratamento dessa doença inclui a realização de exercícios aeróbios. Durante a realização desse exercício, a exacerbação simpática provoca aumento no débito cardíaco para garantir o fluxo sangüíneo necessário para a musculatura ativa. A conseqüência hemodinâmica, desse ajuste cardiovascular, é o aumento da pressão arterial sistólica e a manutenção ou redução da pressão arterial diastólica. Após a finalização do exercício, a pressão arterial diminui, mantendo-se abaixo dos níveis pré-exercícios por períodos prolongados. Esse fenômeno tem sido denominado hipotensão pós-exercício. Essa redução da pressão arterial tem implicações clínicas pois tem magnitude significativa e perdura por um longo período. Embora os mecanismos responsáveis por essa redução ainda precisem ser mais bem esclarecidos, há fortes evidências de que as reduções nas atividades nervosas simpáticas cardíacas e periféricas exercem papel importante nessa problemática. Em longo prazo, o exercício físico aeróbio provoca a redução crônica da pressão arterial, em indivíduos hipertensos. Esse benefício também está relacionado à diminuição da ativação simpática cardíaca e periférica. Em conclusão, exercício aeróbio, agudo e crônico, reduz a pressão arterial. Ele é uma eficiente estratégia simpatolítica no tratamento da hipertensão arterial

Exercício físico e insuficiência cardíaca / Physical exercise and heart failure

Devido aos novos e relevantes benefícios para pacientes portadores de insuficiência cardíaca o exercício físico tem sido recomendado como medida complementar para o tratamento dessa disfunçäo cardiovascular. Nesta revisço, seräo apresentados, num primeiro momento, alguns importantes benefícios alcançados pelo exercício físico regular em pacientes com insuficiências cardíacas e os possíveis mecanismos para explicar esses benefícios. E num segundo momento, será apresentada a prescriçäo de exercício para pacientes com insuficincia cardíaca incluíndo tipo, duraçäo, frequência e intensidade de exercício, adequados para melhorar a qualidade de vida desses pacientes.

Comportamento da frequência cardíaca e da sua variabilidade durante as diferentes fases do exercício físico progressivo máximo / Heart rate response and its variability during different phases of maximal graded exercise

Objetivo - A variabilidade da freqüência cardíaca (VFC) tem sido estudada em repouso, como meio não-invasivo para avaliação da regulação autonômica cardíaca, sendo que sua diminuição está relacionada a maior risco cardiovascular. Entretanto, durante o exercício, quando ocorrem importantes alterações neurais, seu comportamento deve ser melhor documentado. Estudamos o comportamento da freqüência cardíaca (FC) e da sua variabilidade durante as diferentes fases metabólicas do exercício físico progressivo máximo, em jovens. Métodos - Dezessete homens (28+6 anos) realizaram testes ergoespirométrico máximo em cicloergômetro (30 W/3min), determinando-se a FC e a VFC (desvio-padrão) através da onda eletrocardiográfica, amplificada e gravada batimento a batimento em computador, numa freqüência da 125Hz (AT/Codas). Resultados - A FC aumentou concomitantemente ao aumento da intensidade do exercício. A VFC diminuiu progressivamente, atingindo níveis significantes em relação ao repouso a partir de 60 por cento do consumo de oxigênio do pico do exercício, a partir de 45-60 por cento da potência máxima e a partir da intensidade do limiar anaeróbio, estabilizando-se nos períodos subseqüentes. Conclusão - Nossos resultados sugerem que a VFC medida pelo desvio-padrão da FC diminui em fases do exercício nas quais o aumento da FC é determinado, principalmente, por retirada vagal.