Choques inapropriados em portadores de CDI VR versus DR: meta-análise de ensaios clínicos randomizados

FUNDAMENTO: Apesar da evolução tecnológica do cardiodesfibrilador implantável, uma das questões que permanece em aberto é sobre o eventual benefício do cardiodesfibrilador implantável de dupla câmara comparativamente ao de câmara única, para diminuir os choques inapropriados. OBJETIVO: Avaliar, em pacientes com cardiodesfibrilador implantável, qual é o tipo de dispositivo que proporciona menor número de choques inapropriados (câmara dupla versus câmara única). MÉTODOS: Meta-análise da literatura publicada, de estudos randomizados, comparando cardiodesfibrilador implantável de câmara dupla ao de câmara única, que tenham, como endpoint avaliado, a ocorrência de choques inapropriados. RESULTADOS: O cardiodesfibrilador implantável de câmara dupla não mostrou benefícios na redução do número de pacientes com choques inapropriados. Pelo contrário, na análise de efeitos fixos, a associação foi tendencialmente favorável ao cardiodesfibrilador implantável de câmara única (OR = 1,53; IC95%: 0,91-2,57), não obstante a ausência de significado estatístico (p = 0,11). Merece destaque a heterogenia observada nos resultados (I2 = 53%), o que motivou a replicação da análise utilizando um modelo de efeitos aleatórios. No entanto, as diferenças significativas permaneceram na ocorrência de choques inapropriados em ambos os grupos (OR = 1,1; IC95%: 0,37-3,31; p = 0,86). Para complementar a análise, procedeu-se à análise de sensibilidade, na qual se verificou que a exclusão de um estudo resultava na mais baixa heterogenia observada (I2=24%) e na associação com os choques inapropriados significativamente favorável ao cardiodesfibrilador de câmara única (OR = 1,91; IC95%: 1,09-3,37; p = 0,27). CONCLUSÕES: Verificou-se a não existência de evidência clara de superioridade de qualquer um dos dispositivos avaliados.

Intervenções em Dieta e Pressão Arterial na América Latina - Revisão Sistemática e Meta-Análise

Fundamento: Pressão arterial elevada é o principal fator de risco para doenças cardiovasculares. Baixos índices de controle da pressão arterial em populações latino-americanas reforçam a necessidade de reunir evidências sobre terapias eficazes. Objetivo: Avaliar o efeito das intervenções de modificações de dietas sobre pressão arterial em populações latino-americanas. Métodos: Revisão sistemática. Foram pesquisadas diversas bases de dados (MEDLINE-PubMed, Embase, Cochrane Library, CINAHL, Web of Science, Scopus, SciELO, LILACS e BVS) e realizada busca manual até abril de 2013. Foram incluídos estudos paralelos de intervenções em dieta em populações adultas da América Latina reportando pressão arterial (em mmHg) antes e após a intervenção. Resultados: Dos 405 estudos encontrados, 10 ensaios clínicos randomizados foram incluídos e divididos em 3 subgrupos, de acordo com a dieta proposta como intervenção. Houve redução não significativa da pressão arterial sistólica nos subgrupos de substituição mineral -4,82 (IC 95%: -11,36 a 1,73 mmHg) e padrões complexos -3,17 (IC 95%: -7,62 a 1,28 mmHg). Para a pressão arterial diastólica, com exceção do subgrupo de dietas hiperproteicas, todos os subgrupos apresentaram redução significativa, com -4,66 (IC 95%: -9,21 a -0,12 mmHg) e -4,55 (IC 95%: -7,04 a -2,06 mmHg) para substituição mineral e padrões complexos, respectivamente. Conclusão: A evidência disponível sobre os efeitos de alterações de dieta na pressão arterial em populações latino-americanas indica um efeito homogêneo, porém não significativo, para pressão arterial sistólica. Estudos maiores e com maior rigor metodológico são necessários para construção de evidência robusta.

Effects of Yoga in Patients with Chronic Heart Failure: A Meta-Analysis

The use of yoga as an effective cardiac rehabilitation in patients with chronic heart failure (CHF) remains controversial. We performed a meta-analysis to examine the effects of yoga on exercise capacity and health-related quality of life (HRQOL) in patients with CHF. Methods: We searched MEDLINE, Cochrane Central Register of Controlled Trials, Excerpta Medica database, LILACS, Physiotherapy Evidence Database, The Scientific Electronic Library Online, and Cumulative Index to Nursing and Allied Health (from the earliest date available to December 2013) for randomized controlled trials (RCTs) examining the effects of yoga versus exercise and/or of yoga versus control on exercise capacity (peakVO2) and quality-of-life (HRQOL) in CHF. Two reviewers selected studies independently. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated, and heterogeneity was assessed using the I2 test. Two studies met the selection criteria (total: 30 yoga and 29 control patients). The results suggested that yoga compared with control had a positive impact on peak VO2 and HRQOL. Peak VO2, WMD (3.87 95% CI: 1.95 to 5.80), and global HRQOL standardized mean differences (-12.46 95% CI: -22.49 to -2.43) improved in the yoga group compared to the control group. Yoga enhances peak VO2 and HRQOL in patients with CHF and could be considered for inclusion in cardiac rehabilitation programs. Larger RCTs are required to further investigate the effects of yoga in patients with CHF.

Death and Disability in Patients with Sleep Apnea - A Meta-analysis

Background:Several studies have been attempting to ascertain the risks of Sleep Apnea Syndrome (SAS) and its morbidity and mortality.Objective:The main objective was to verify whether SAS increases the risk of death; the secondary objective was to evaluate its morbidity in relation to cardiovascular disease and the number of days hospitalized.Methods:A systematic review and a meta-analysis were performed of the published literature. The research focused on studies comparing the number of deaths in patients with untreated SAS and in patients with non-SAS.Results:The meta-analysis was based on 13 articles, corresponding to a total of 13394 participants divided into two groups (non-SAS = 6631; SAS = 6763). The meta-analysis revealed a clear association of SAS with the occurrence of fatal events, where the presence of SAS corresponded to a 61% higher risk of total mortality (OR=1.61; CI: 1.43 - 1.81; p < 0.00001), while the risk of death from cardiac causes was 2.52 times higher in these patients (OR = 2.52; IC: 1.80 - 3.52; p < 0.00001). Similar results were obtained for mortality from other causes (OR = 1.68; CI: 1.08 - 2.61; p = 0.02). Resembling results were obtained in the remaining outcomes: non-fatal cardiovascular events were higher in the SAS group (OR = 2.46; IC: 1.80 - 3.36; p < 0.00001), the average number of days hospitalized was also higher in the SAS group (IV = 18.09; IC: 13.34 - 22.84; p < 0.00001).Conclusion:The results show that untreated SAS significantly increases the risk of death, cardiovascular events and the average number of days hospitalized.

Meta-Analysis of Ultrafiltration versus Diuretics Treatment Option for Overload Volume Reduction in Patients with Acute Decompensated Heart Failure

Introduction: Although diuretics are mainly used for the treatment of acute decompensated heart failure (ADHF), inadequate responses and complications have led to the use of extracorporeal ultrafiltration (UF) as an alternative strategy for reducing volume overloads in patients with ADHF. Objective: The aim of our study is to perform meta-analysis of the results obtained from studies on extracorporeal venous ultrafiltration and compare them with those of standard diuretic treatment for overload volume reduction in acute decompensated heart failure. Methods: MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases were systematically searched using a pre‑specified criterion. Pooled estimates of outcomes after 48 h (weight change, serum creatinine level, and all-cause mortality) were computed using random effect models. Pooled weighted mean differences were calculated for weight loss and change in creatinine level, whereas a pooled risk ratio was used for the analysis of binary all-cause mortality outcome. Results: A total of nine studies, involving 613 patients, met the eligibility criteria. The mean weight loss in patients who underwent UF therapy was 1.78 kg [95% Confidence Interval (CI): −2.65 to −0.91 kg; p < 0.001) more than those who received standard diuretic therapy. The post-intervention creatinine level, however, was not significantly different (mean change = −0.25 mg/dL; 95% CI: −0.56 to 0.06 mg/dL; p = 0.112). The risk of all-cause mortality persisted in patients treated with UF compared with patients treated with standard diuretics (Pooled RR = 1.00; 95% CI: 0.64–1.56; p = 0.993). Conclusion: Compared with standard diuretic therapy, UF treatment for overload volume reduction in individuals suffering from ADHF, resulted in significant reduction of body weight within 48 h. However, no significant decrease of serum creatinine level or reduction of all-cause mortality was observed.

Discriminative classifiers for speaker recognition

Speaker Recognition, Speaker Verification, Sparse Kernel Logistic Regression, Support Vector Machine

Network Meta-analysis to Synthesize Evidence for Decision Making in Cardiovascular Research

Abstract Clinical decision-making requires synthesis of evidence from literature reviews focused on a specific theme. Evidence synthesis is performed with qualitative assessments and systematic reviews of randomized clinical trials, typically covering statistical pooling with pairwise meta-analyses. These methods include adjusted indirect comparison meta-analysis, network meta-analysis, and mixed-treatment comparison. These tools allow synthesis of evidence and comparison of effectiveness in cardiovascular research.

maintenance model for systems with phase-type distributed times to failure

Magdeburg, Univ., Fak. für Mathematik, Diss., 2010

Machine learning with Lipschitz classifiers

Magdeburg, Univ., Fak. für Elektrotechnik und Informationstechnik, Diss., 2010

Acute Effects of Exercise on Blood Pressure: A Meta-Analytic Investigation

Abstract Hypertension affects 25% of the world's population and is considered a risk factor for cardiovascular disorders and other diseases. The aim of this study was to examine the evidence regarding the acute effect of exercise on blood pressure (BP) using meta-analytic measures. Sixty-five studies were compared using effect sizes (ES), and heterogeneity and Z tests to determine whether the ES were different from zero. The mean corrected global ES for exercise conditions were -0.56 (-4.80 mmHg) for systolic BP (sBP) and -0.44 (-3.19 mmHg) for diastolic BP (dBP; z ≠ 0 for all; p < 0.05). The reduction in BP was significant regardless of the participant's initial BP level, gender, physical activity level, antihypertensive drug intake, type of BP measurement, time of day in which the BP was measured, type of exercise performed, and exercise training program (p < 0.05 for all). ANOVA tests revealed that BP reductions were greater if participants were males, not receiving antihypertensive medication, physically active, and if the exercise performed was jogging. A significant inverse correlation was found between age and BP ES, body mass index (BMI) and sBP ES, duration of the exercise's session and sBP ES, and between the number of sets performed in the resistance exercise program and sBP ES (p < 0.05). Regardless of the characteristics of the participants and exercise, there was a reduction in BP in the hours following an exercise session. However, the hypotensive effect was greater when the exercise was performed as a preventive strategy in those physically active and without antihypertensive medication.

Keyword search across distributed heterogenous structured data sources

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

Collaboration process design for ideation in distributed environments : approaches to support collaborative ideation in global virtual groups using technological support

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

Increasing the scalability and the speedup of a fish school distributed simulator

El present treball fa un anàlisi i desenvolupament sobre les millores en la velocitat i en l’escalabilitat d'un simulador distribuït de grups de peixos. Aquests resultats s’han obtingut fent servir una nova estratègia de comunicació per als processos lògics (LPs) i canvis en l'algoritme de selecció de veïns que s'aplica a cadascun dels peixos en cada pas de simulació. L’idea proposada permet que cada procés lògic anticipi futures necessitats de dades pels seus veïns reduint el temps de comunicació al limitar la quantitat de missatges intercanviats entre els LPs. El nou algoritme de selecció dels veïns es va desenvolupar amb l'objectiu d'evitar treball innecessari permetent la disminució de les instruccions executades en cada pas de simulació i per cadascun del peixos simulats reduint de forma significativa el temps de simulació.

Safety and occlusion rates of surgical treatment of unruptured intracranial aneurysms: a systematic review and meta-analysis of the literature from 1990 to 2011.

BACKGROUND AND PURPOSE: Surgical clipping of unruptured intracranial aneurysms (UIAs) has recently been challenged by the emergence of endovascular treatment. We performed an updated systematic review and meta-analysis on the surgical treatment of UIAs, in an attempt to determine the aneurysm occlusion rates and safety of surgery in the modern era. METHODS: A detailed protocol was developed prior to conducting the review according to the Cochrane Collaboration guidelines. Electronic databases spanning January 1990-April 2011 were searched, complemented by hand searching. Heterogeneity was assessed using I(2), and publication bias with funnel plots. Surgical mortality and morbidity were analysed with weighted random effect models. RESULTS: 60 studies with 9845 patients harbouring 10 845 aneurysms were included. Mortality occurred in 157 patients (1.7%; 99% CI 0.9% to 3.0%; I(2)=82%). Unfavourable outcomes, including death, occurred in 692 patients (6.7%; 99% CI 4.9% to 9.0%; I(2)=85%). Morbidity rates were significantly greater in higher quality studies, and with large or posterior circulation aneurysms. Reported morbidity rates decreased over time. Studies were generally of poor quality; funnel plots showed heterogeneous results and publication bias, and data on aneurysm occlusion rates were scant. CONCLUSIONS: In studies published between 1990 and 2011, clipping of UIAs was associated with 1.7% mortality and 6.7% overall morbidity. The reputed durability of clipping has not been rigorously documented. Due to the quality of the included studies, the available literature cannot properly guide clinical decisions.