Physiological and Stroke Parameters to Assess Aerobic Capacity in Swimming

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Force patterns of hypoxic myocardium applied to oxygenated muscle preparations: Comparison with effects of regional ischemia on the contraction of non-ischemic myocardium

Objective: To examine the basis for local wall motion abnormalities commonly seen in patients with ischemic heart disease, computer-controlled isolated muscle studies were carried out. Methods: Force patterns of physiologically sequenced contractions (PSCs) from rat left ventricular muscle preparations under well-oxygenated conditions and during periods of hypoxia and reoxygenation were recorded and stored in a computer. Force patterns of hypoxic-reoxygenating and oxygenated myocardium were applied to oxygenated and hypoxic-reoxygenating myocardium, respectively. Results: Observed patterns of shortening and lengthening closely resemble those obtained from ischemic and non-ischemic myocardial segments using ultrasonic crystals in intact dog hearts during coronary occlusion and reperfusion, and are similar to findings reported in angiographic studies of humans with coronary artery disease. Conclusion: The current study, demonstrating motions of oxygenated isolated muscle preparations which are similar to those in perfused segments of intact hearts with regional ischemia, supports the concept that the multiple motions of both ischemic and non-ischemic segments seen in regional myocardial disease can be explained by interactions of strongly and weakly contracting muscle during the physiologic cardiac cycle.

Risk-assessment algorithm and recommendations for venous thromboembolism prophylaxis in medical patients

The risk for venous thromboembolism (VTE) in medical patients is high, but risk assessment is rarely performed because there is not yet a good method to identify candidates for prophylaxis. Purpose: To perform a systematic review about VTE risk factors (RFs) in hospitalized medical patients and generate recommendations (RECs) for prophylaxis that can be implemented into practice. Data sources: A multidisciplinary group of experts from 12 Brazilian Medical Societies searched MEDLINE, Cochrane, and LILACS. Study selection: Two experts independently classified the evidence for each RF by its scientific quality in a standardized manner. A risk-assessment algorithm was created based on the results of the review. Data synthesis: Several VTE RFs have enough evidence to support RECs for prophylaxis in hospitalized medical patients (eg, increasing age, heart failure, and stroke). Other factors are considered adjuncts of risk (eg, varices, obesity, and infections). According to the algorithm, hospitalized medical patients ≥40 years-old with decreased mobility, and ≥1 RFs should receive chemoprophylaxis with heparin, provided they don't have contraindications. High prophylactic doses of unfractionated heparin or low-molecular-weight-heparin must be administered and maintained for 6-14 days. Conclusions: A multidisciplinary group generated evidence-based RECs and an easy-to-use algorithm to facilitate VTE prophylaxis in medical patients. © 2007 Rocha et al, publisher and licensee Dove Medical Press Ltd.

Effects of gender on stroke rates, critical speed and velocity of a 30-min swim in young swimmers

Our objective was to analyze the effect of gender on the relationship between stroke rates corresponding to critical speed (SRCS) and maximal speed of 30 min (SRS30) in young swimmers. Twenty two males (GM1) (Age = 15.4 ± 2.1 yr., Body mass = 63.7 ± 12.9 kg, Stature = 1.73 ± 0.09 m) and fourteen female (GF) swimmers (Age = 15.1 ± 1.6 yr., Body mass = 58.3 ± 8.8 kg, Stature = 1.65 ± 0.06 m) were studied. A subset of males (GM2) was matched to the GF by their velocity for a 30 min swim (S30). The critical speed (CS) was determined through the slope of the linear regression line between the distances (200 and 400 m) and participant's respective times. CS was significantly higher than S30 in males (GM1 - 1.25 and 1.16 and GM2 - 1.21 and 1.12 m·s-1) and females (GF - 1.15 and 1.11 m·s-1). There was no significant difference between SRCS and SRS30 in males (GM1 - 34.16 and 32.32 and GM2 - 34.67 and 32.46 cycle·s-1, respectively) and females (GF - 34.18 and 33.67 cycle·s-1-1, respectively). There was a significant correlation between CS and S30 (GM1 - r = 0.89, GF - r = 0.94 and GM2 - r = 0.90) and between SRCS and SRS30 (GM1 - r = 0.89, GF - r = 0.80 and GM2 - r = 0.88). Thus, the relationship between SRCS and SRS30 is not influenced by gender, in swimmers with similar and different aerobic capacity levels. ©Journal of Sports Science and Medicine (2007).

Stroke phases responses around maximal lactate steady state in front crawl

The objective of this study was to analyze changes in stroke rate (SR), stroke length (SL) and stroke phases (entry and catch, pull, push and recovery) when swimming at (MLSS) and above (102.5% MLSS) the maximal lactate steady state. Twelve endurance swimmers (21±8 year, 1.77±0.10m and 71.6±7.7kg) performed in different days the following tests: (1) 200- and 400-m all-out tests, to determine critical speed (CS), and; (2) 2-4 30-min sub-maximal constant-speed tests, to determine the MLSS and 102.5% MLSS. There was significant difference among MLSS (1.22±0.05ms-1), 102.5% MLSS (1.25±0.04ms-1) and CS (1.30±0.08ms-1). SR and SL were maintained between the 10th and 30th minute of the test swum at MLSS and have modified significantly at 102.5% MLSS (SR - 30.9±3.4 and 32.2±3.5cyclesmin-1 and SL - 2.47±0.2 and 2.38±0.2mcycle-1, respectively). All stroke phases were maintained at 10th and 30th minute at MLSS. However, the relative duration of propulsive phase B (pull) increased significantly at 102.5% MLSS (21.7±3.4% and 22.9±3.9%, respectively). Therefore, the metabolic condition may influence the stroke parameters (SR and SL) and stroke strategy to maintain the speed during swim tests lasting 30min. © 2010 Sports Medicine Australia.

Prevention of hypertension in patients with pre-hypertension: Protocol for the PREVER-prevention trial

Background: Blood pressure (BP) within pre-hypertensive levels confers higher cardiovascular risk and is an intermediate stage for full hypertension, which develops in an annual rate of 7 out of 100 individuals with 40 to 50 years of age. Non-drug interventions to prevent hypertension have had low effectiveness. In individuals with previous cardiovascular disease or diabetes, the use of BP-lowering agents reduces the incidence of major cardiovascular events. In the absence of higher baseline risk, the use of BP agents reduces the incidence of hypertension. The PREVER-prevention trial aims to investigate the efficacy, safety and feasibility of a population-based intervention to prevent the incidence of hypertension and the development of target-organ damage.Methods: This is a randomized, double-blind, placebo-controlled clinical trial, with participants aged 30 to 70 years, with pre-hypertension. The trial arms will be chlorthalidone 12.5 mg plus amiloride 2.5 mg or identical placebo. The primary outcomes will be the incidence of hypertension, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new sub-clinical atherosclerosis, and sudden death. The study will last 18 months. The sample size was calculated on the basis of an incidence of hypertension of 14% in the control group, a size effect of 40%, power of 85% and P alpha of 5%, resulting in 625 participants per group. The project was approved by the Ethics committee of each participating institution.Discussion: The early use of blood pressure-lowering drugs, particularly diuretics, which act on the main mechanism of blood pressure rising with age, may prevent cardiovascular events and the incidence of hypertension in individuals with hypertension. If this intervention shows to be effective and safe in a population-based perspective, it could be the basis for an innovative public health program to prevent hypertension in Brazil.Trial Registration: Clinical Trials NCT00970931. © 2011 Fuchs et al; licensee BioMed Central Ltd.

Trochlear nerve palsy associated with claude bernard-horner syndrome after brainstem stroke

The association of unilateral trochlear nerve palsy with Claude Bernard-Horner syndrome represents a rare clinical condition. We present the case of a patient with this unusual presentation. The investigation performed implicated cerebrovascular disease as the underlying cause of the condition in this patient. © 2011 S. Karger AG, Basel.

Fondaparinux em intervenção coronária percutânea no tratamento da síndrome coronária aguda

Background: Fondaparinux is considered an agent with a well-established safety and efficacy profile in the treatment of non-ST segment elevation acute coronary syndromes, but when used alone, is associated to a higher incidence of thrombotic complications during invasive coronary procedures, requiring the supplementation of an anti-IIa agent. This study aimed to evaluate the efficacy and safety of percutaneous coronary intervention (PCI) in patients with non-ST segment elevation acute coronary syndromes previously treated with fondaparinux. Methods: Prospective, controlled registry enrolling 127 consecutive patients submitted to an early invasive stratification during treatment with fondaparinux, with supplementation of intravenous unfractionated heparin at a dose of 85 U/kg at the time of PCI. Results: The rate of the composite primary endpoint including death, acute myocardial infarction, stroke, stent thrombosis or emergency myocardial revascularization was 3.2%. The cumulative incidence of major bleeding and vascular complications was 3.2%. There were no cases of guidecatheter thrombosis or abrupt vessel closure. Conclusions: PCI in patients with acute coronary syndromes receiving fondaparinux is associated with a low rate of major adverse cardiovascular ischemic events and severe hemorrhagic complications. Supplementation of unfractionated heparin during the invasive procedures eliminates the risk of catheter-related thrombosis.

Low level laser therapy increases angiogenesis in a model of ischemic skin flap in rats mediated by VEGF, HIF-1α and MMP-2

It is known that low level laser therapy is able to improve skin flap viability by increasing angiogenesis. However, the mechanism for new blood vessel formation is not completely understood. Here, we investigated the effects of 660 nm and 780 nm lasers at fluences of 30 and 40 J/cm2 on three important mediators activated during angiogenesis. Sixty male Wistar rats were used and randomly divided into five groups with twelve animals each. Groups were distributed as follows: skin flap surgery non-irradiated group as a control; skin flap surgery irradiated with 660 nm laser at a fluence of 30 or 40 J/cm2 and skin flap surgery irradiated with 780 nm laser at a fluence of 30 or 40 J/cm2. The random skin flap was performed measuring 10 × 4 cm, with a plastic sheet interposed between the flap and the donor site. Laser irradiation was performed on 24 points covering the flap and surrounding skin immediately after the surgery and for 7 consecutive days thereafter. Tissues were collected, and the number of vessels, angiogenesis markers (vascular endothelial growth factor, VEGF and hypoxia inducible factor, HIF-1α) and a tissue remodeling marker (matrix metalloproteinase, MMP-2) were analyzed. LLLT increased an angiogenesis, HIF-1α and VEGF expression and decrease MMP-2 activity. These phenomena were dependent on the fluences, and wavelengths used. In this study we showed that LLLT may improve the healing of skin flaps by enhancing the amount of new vessels formed in the tissue. Both 660 nm and 780 nm lasers were able to modulate VEGF secretion, MMP-2 activity and HIF-1α expression in a dose dependent manner. © 2013 Published by Elsevier B.V.

Comparison between the six-minute walk test and the six-minute step test in post stroke patients

Background: The Stroke remains one of the major chronic diseases worldwide, and is considered a major cause of disability, which results not only in persistent neurological deficits, but also in the high physical deconditioning, nevertheless there are not many forms of assessing functional capacity in this population. We aimed to investigate the feasibility of the Six Minute Walk Teste and the Six-Minute Step Test (6MST) in post-stroke patients and compare the behavior of physiological variables during the 6MST and the Six-Minute Walk Test (6MWT), by correlating the functional performance obtained in both tests. Method. The 6MWT was carried out according to the American Thoracic Society (ATS) and the 6MST was performed in six minutes in order to compare it to the 6MWT in a 20 cm step. Was included post-stroke individuals able to walk without aid. All of them did the 6MWT and the 6MST. Results: 12 patients participated in the study. There was no statistical difference in the parameters analyzed when tests were compared. There was poor correlation between the functional performance in both tests. Conclusion: The 6MWT and the 6MST is feasible for post-stroke patients and physiological responses are equal during the performance of both tests. However, there was no correlation with respect to functional performance, which was assessed by the distance walked in the 6MWT and by the number of steps climbed in the 6MST. © 2013 da Silva et al.; licensee BioMed Central Ltd.

Carotid artery atherosclerotic profile as a predictor of the aorta atherosclerotic profile in patients with cerebrovascular events

Background: It is well known that the presence of atheroma of the thoracic aorta is a risk factor for cerebrovascular events. We sought to evaluate whether the presence and the morphology of atherosclerotic plaque in the carotid artery detected by duplex ultrasonography is associated with disease in the proximal aorta visualized by transesophageal echocardiogram in patients with a cerebrovascular event. Methods: We carried out a cross-sectional prospective study including 147 consecutive patients with prior stroke or transient ischemic attack (TIA). Neurological evaluations were performed by an expert neurologist using clinical and tomographic diagnostic criteria including the definition of etiology and whether the patient suffered from stroke or TIA. Transthoracic and transesophageal echocardiograms and carotid artery duplex ultrasonography were performed by the same examiner. Patients with and without plaque in the carotid artery were compared using Student's t test or the χ2 test. Regression analysis was used to determine whether the presence of plaque in the carotid artery was predictive of the presence of plaque in the proximal aorta and to analyze the relationship between the echogenicity of carotid and aortic plaques. The significance level was set at p < 0.05. Results: All 147 patients (95 men) were included in the analysis. Patients' ages ranged from 23 to 85 years (65 ± 12.4 years). Most of the patients (58.5%) were Caucasian, while 41.5% were African-Brazilian. Arterial hypertension, diabetes and tobacco use were more frequent among patients with atherosclerotic plaque in the aorta. A normal carotid intima-media thickness halved the risk of atherosclerotic plaque in the aorta [odds ratio (OR) 0.46, 95% confidence interval (CI) 0.23-0.91; p = 0.026]. The presence of carotid plaque increased the risk of aortic plaque by 70-fold (OR 73.2, 95% CI 25.6-2,018.6; p < 0.001) in univariate analysis. The absence of atherosclerotic plaque in the carotid artery reduced the risk of plaque in the aorta to almost 0 (OR 0.014, 95% CI 0.004-0.041; p < 0.001). Considering the 86 patients with both aortic and carotid plaques, the presence of hypoechoic plaque in the carotid artery was a predictor of hypoechoic plaque in the aorta (OR 10.1, 95% CI 3.3-31.2; p < 0.001). Conclusions: The carotid artery atherosclerotic profile defined by ultrasonography is a strong predictor of the atherosclerotic profile of the proximal aorta. This should be taken into consideration before referring patients with acute cerebrovascular events for transesophageal echocardiogram. © 2013 S. Karger AG, Basel.

O efeito do sabor azedo e da temperatura fria no tempo de trânsito faríngeo da deglutição em indivíduos após acidente vascular encefálico hemisférico isquêmico

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)