Sítios endocárdicos alternativos na estimulação cardíaca artificial

A estimulação ventricular direita convencional pode estar associada a efeitos deletérios sobre a função cardíaca. A necessidade de uma estimulação cardíaca artificial mais fisiológica é, indiscutivelmente, um dos pontos mais importantes na área da eletroterapia cardíaca. Os algoritmos de programação para a manutenção da condução atrioventricular própria, a estimulação de sítios endocárdicos alternativos e a terapia de ressincronização cardíaca são utilizados com o intuito de alcançar este objetivo. A estimulação do feixe de His e a estimulação septal têm sido estudadas como sítios endocárdicos alternativos para o posicionamento do eletrodo no ventrículo direito. A estimulação septal representa uma alternativa simples, prática e sem custos adicionais e com potenciais benefícios na redução dos efeitos deletérios da estimulação do ventrículo direito. Entretanto, esse sítio alternativo envolve um grupo heterogêneo de pacientes e apresenta resultados conflitantes quanto ao seu benefício clínico a longo prazo. Este artigo faz uma revisão das evidências científicas sobre os sítios alternativos de estimulação ventricular direita, com ênfase na segurança do procedimento, na medida dos parâmetros eletrofisiológicos, na avaliação da função ventricular esquerda e no acompanhamento clínico dos pacientes.

Biofilme em marca-passo artificial: ficção ou realidade?

A estimulação cardíaca artificial por meio de marca-passo cardíaco representa uma das alternativas mais promissoras no tratamento das arritmias, entretanto pode ocasionar reações singulares ou complexas, precoces ou tardias. Neste estudo, objetivou-se descrever as evidências científicas sobre o risco de infecção e formação de biofilme associado ao marca-passo cardíaco. Trata-se de um estudo de revisão integrativa da literatura. Totalizaram-se 14 publicações classificadas em três categorias temáticas: diagnóstico (microbiológico e/ou clínico), complicações e terapêutica das infecções. Os Staphylococcus epidermidis e os Staphylococcus aureus foram os microrganismos mais frequentemente isolados. Não foi possível determinar a incidência da infecção associada aos marca-passos, uma vez que os estudos eram em geral de prevalência. Em termos de terapêutica destacou-se a remoção completa dos marca-passos, especialmente nos casos de suspeita de biofilme. Ainda é controverso o uso da profilaxia antibiótica sistêmica na redução da incidência da infecção associada ao implante de marca-passo

Neural mechanisms of attentional selection in vision : locations, features, and objects

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2012

Multivariate Analysis for Animal Selection in Experimental Research

Background: Several researchers seek methods for the selection of homogeneous groups of animals in experimental studies, a fact justified because homogeneity is an indispensable prerequisite for casualization of treatments. The lack of robust methods that comply with statistical and biological principles is the reason why researchers use empirical or subjective methods, influencing their results. Objective: To develop a multivariate statistical model for the selection of a homogeneous group of animals for experimental research and to elaborate a computational package to use it. Methods: The set of echocardiographic data of 115 male Wistar rats with supravalvular aortic stenosis (AoS) was used as an example of model development. Initially, the data were standardized, and became dimensionless. Then, the variance matrix of the set was submitted to principal components analysis (PCA), aiming at reducing the parametric space and at retaining the relevant variability. That technique established a new Cartesian system into which the animals were allocated, and finally the confidence region (ellipsoid) was built for the profile of the animals’ homogeneous responses. The animals located inside the ellipsoid were considered as belonging to the homogeneous batch; those outside the ellipsoid were considered spurious. Results: The PCA established eight descriptive axes that represented the accumulated variance of the data set in 88.71%. The allocation of the animals in the new system and the construction of the confidence region revealed six spurious animals as compared to the homogeneous batch of 109 animals. Conclusion: The biometric criterion presented proved to be effective, because it considers the animal as a whole, analyzing jointly all parameters measured, in addition to having a small discard rate.

Selection of information in auditory virtual reality

ERP, auditory virtual reality, dichotic listening, selective auditory attention, cocktail-party phenomenon, HRTF

The descent of man, and selection in relation to sex. By Charles Darwin ...

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Development and Validation of Predictive Models of Cardiac Mortality and Transplantation in Resynchronization Therapy

AbstractBackground:30-40% of cardiac resynchronization therapy cases do not achieve favorable outcomes.Objective:This study aimed to develop predictive models for the combined endpoint of cardiac death and transplantation (Tx) at different stages of cardiac resynchronization therapy (CRT).Methods:Prospective observational study of 116 patients aged 64.8 ± 11.1 years, 68.1% of whom had functional class (FC) III and 31.9% had ambulatory class IV. Clinical, electrocardiographic and echocardiographic variables were assessed by using Cox regression and Kaplan-Meier curves.Results:The cardiac mortality/Tx rate was 16.3% during the follow-up period of 34.0 ± 17.9 months. Prior to implantation, right ventricular dysfunction (RVD), ejection fraction < 25% and use of high doses of diuretics (HDD) increased the risk of cardiac death and Tx by 3.9-, 4.8-, and 5.9-fold, respectively. In the first year after CRT, RVD, HDD and hospitalization due to congestive heart failure increased the risk of death at hazard ratios of 3.5, 5.3, and 12.5, respectively. In the second year after CRT, RVD and FC III/IV were significant risk factors of mortality in the multivariate Cox model. The accuracy rates of the models were 84.6% at preimplantation, 93% in the first year after CRT, and 90.5% in the second year after CRT. The models were validated by bootstrapping.Conclusion:We developed predictive models of cardiac death and Tx at different stages of CRT based on the analysis of simple and easily obtainable clinical and echocardiographic variables. The models showed good accuracy and adjustment, were validated internally, and are useful in the selection, monitoring and counseling of patients indicated for CRT.

The descent of man, and selection in relation to sex / by Charles Darwin.

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Efficacy of Patient Selection for Diagnostic Coronary Angiography in Suspected Coronary Artery Disease

AbstractBackground:Guidelines recommend that in suspected stable coronary artery disease (CAD), a clinical (non-invasive) evaluation should be performed before coronary angiography.Objective:We assessed the efficacy of patient selection for coronary angiography in suspected stable CAD.Methods:We prospectively selected consecutive patients without known CAD, referred to a high-volume tertiary center. Demographic characteristics, risk factors, symptoms and non-invasive test results were correlated to the presence of obstructive CAD. We estimated the CAD probability based on available clinical data and the incremental diagnostic value of previous non-invasive tests.Results:A total of 830 patients were included; median age was 61 years, 49.3% were males, 81% had hypertension and 35.5% were diabetics. Non-invasive tests were performed in 64.8% of the patients. At coronary angiography, 23.8% of the patients had obstructive CAD. The independent predictors for obstructive CAD were: male gender (odds ratio [OR], 3.95; confidence interval [CI] 95%, 2.70 - 5.77), age (OR for 5 years increment, 1.15; CI 95%, 1.06 - 1.26), diabetes (OR, 2.01; CI 95%, 1.40 - 2.90), dyslipidemia (OR, 2.02; CI 95%, 1.32 - 3.07), typical angina (OR, 2.92; CI 95%, 1.77 - 4.83) and previous non-invasive test (OR 1.54; CI 95% 1.05 - 2.27).Conclusions:In this study, less than a quarter of the patients referred for coronary angiography with suspected CAD had the diagnosis confirmed. A better clinical and non-invasive assessment is necessary, to improve the efficacy of patient selection for coronary angiography.

The descent of man, and selection in relation to sex. By Charles Darwin ...

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The descent of man, and selection in relation to sex. By Charles Darwin.

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