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BackgroundSurgical ablation (SA) is a key treatment for atrial fibrillation (AF) patients undergoing heart surgery. However, direct comparisons between SA and non-mitral valve (non-MV) surgery alone are lacking. We performed a systematic review and meta-analysis comparing concomitant SA to isolated non-MV surgery in AF patients.MethodsMEDLINE, Embase and Cochrane were searched. Outcomes of interest were: (1) postoperative AF (POAF); (2) early all-cause mortality; (3) postoperative pacemaker implantation and (4) stroke. Additionally, a subgroup analysis comparing randomised controlled trials (RCTs) and propensity score-matched studies (PSM) was conducted. Risk ratios (RRs) and their respective 95% CI were calculated using a random effects model.ResultsAfter screening 6423 citations, we included 2 RCTs and 5 PSM studies encompassing 39 348 AF patients undergoing non-MV surgery, of whom 18 394 (46.7%) underwent SA. Compared with isolated non-MV surgery, SA was associated with significant POAF reduction (RR: 0.73; 95% CI: 0.67 to 0.79; I2=0%) and higher risk of postoperative pacemaker implantation (RR: 1.34; 95% CI: 1.14 to 1.57, I2=0%) compared with surgery alone. No differences were found in early all-cause mortality (RR: 0.96; 95% CI: 0.76 to 1.22; I2=65%) and postoperative stroke (RR: 1.06; 95% CI: 0.89 to 1.26; I2=0%). The subgroup analysis comparing RCTs and PSM showed significant consistency among the different designs.ConclusionsIn this meta-analysis, SA was associated with POAF reduction in non-MV surgery. In terms of safety, it was suggested that although no difference in early mortality and postoperative stroke was observed, SA had a higher risk of pacemaker implantation than isolated non-MV surgery.

We assessed the spatiotemporal co-occurrence patterns of a fish assemblage in the watershed of a stream in the western Amazon basin, and verified the influence of abiotic factors (physicochemical variables and the hydrological phase) on these patterns. We also examined whether species that were more similar in their tolerance of physicochemical variables tended to co-occur more frequently. The structure of the assemblage was evaluated using the standardized effect size (SES) of the C-score index and null models, with the SES being used as an indicator of the organization of the assemblage. We employed linear regression models to investigate the influence of precipitation levels and physicochemical variables on the SES. We calculated the outlying mean index and ran a Mantel test on the checkerboard unit matrix of the C-score and tolerance values to assess the influence of species tolerance on co-occurrence patterns. Finally, we examined the correlations between species pairs and both physicochemical variables and adjacent land use. We observed patterns of aggregation or randomness in varying degrees at different scales. Increased precipitation influenced the establishment of random patterns, while species pairs correlated primarily with the degree of preservation of the local habitat at each study site. During the dry season, species that were more similar to each other in their environmental tolerance tended to co-occur more systematically. If the current levels of change in land use in the study area continue, the fish assemblage investigated here may suffer a significant loss of diversity, as well as destabilization of its structure, with a high possibility of local extinction of the most sensitive species.

Abstract Few studies have investigated the ichthyofauna of streams in the upper Purus River basin, hampering efforts to understand the diversity of these numerous bodies of water. This study presents the first inventory of the ichthyofauna in the upper Purus-Antimary interfluve, southwestern Amazonia. The study was based on data compiled from various sources, including online repositories, scientific articles, and fish collected from four streams in a protected area. We assessed species richness, distribution area, conservation status and anthropogenic threats. The fieldwork study was carried out in four \"terra firme\" streams in the Purus River basin, with fieldwork conducted during the rainy season in March and November 2017. We identified a total of 92 species, 26 families, and six orders. The order Characiformes exhibited the highest species richness with 42 species, followed by Siluriformes with 34, and Gymnotiformes with 8 species. The Characidae family was the most diverse, with 25 species, followed by Loricariidae with 11 species and Callichthyidae with seven species. The collected fish samples totaled 1,794 individuals representing 58 species, 22 families, and 4 orders. The most abundant species were Knodus smithi with 307 individuals, followed by Chrysobrycon hesperus with 247 and Tyttocharax madeirae with 165. Most species were classified as being of low conservation concern. The study expanded the known extent of occurrence for Anablepsoides hoetmeri to 2,163.777 km2. Our findings underscore the importance of conserving aquatic habitats and riparian vegetation within the upper Purus-Antimary interfluve, given the presence of a rich and restricted ichthyofauna. Furthermore, we highlight the significant risks posed by anthropogenic pressures such as deforestation for pastures, wildfires, and illegal fishing activities. Resumo Poucos estudos investigaram a ictiofauna de riachos na bacia do alto rio Purus, dificultando os esforços para entender a diversidade desses numerosos corpos d'água. Este estudo apresenta o primeiro inventário da ictiofauna no interflúvio superior Purus-Antimary, sudoeste da Amazônia. O estudo foi baseado em dados compilados de várias fontes, incluindo repositórios online, artigos científicos e peixes coletados de quatro riachos em uma área protegida. Avaliamos a riqueza de espécies, área de distribuição, estado de conservação e ameaças antropogênicas. O estudo de campo foi realizado em quatro riachos de terra firme na bacia do rio Purus, com trabalho de campo conduzido durante a estação chuvosa em março e novembro de 2017. Identificamos um total de 92 espécies, 26 famílias e seis ordens. A ordem Characiformes exibiu a maior riqueza de espécies com 42 espécies, seguida por Siluriformes com 34 e Gymnotiformes com 8 espécies. A família Characidae foi a mais diversa, com 25 espécies, seguida por Loricariidae com 11 e Callichthyidae com 7 espécies. As amostras de peixes coletadas totalizaram 1.794 indivíduos representando 58 espécies, 22 famílias e 4 ordens. As espécies mais abundantes foram Knodus smithi com 307 indivíduos, seguida por Chrysobrycon hesperus com 247 e Tyttocharax madeirae com 165. A maioria das espécies foi classificada como de baixa preocupação de conservação. O estudo expandiu a extensão conhecida de ocorrência de Anablepsoides hoetmeri para 2.163,777 km2. Nossas descobertas ressaltam a importância da conservação de habitats aquáticos e vegetação ribeirinha dentro do interflúvio superior Purus-Antimary, dada a presença de uma ictiofauna rica e restrita. Além disso, destacamos os riscos significativos representados por pressões antropogênicas, como desmatamento para pastagens, incêndios florestais e atividades de pesca ilegal.

Abstract We analyzed the length-weight relationships of 12 lesser-known fish species sampled in four streams in the Southwestern Amazon, in Acre State, Brazil. Diurnal and nocturnal sampling took place in four streams in 150-meter sessions in March and November 2017. Linear regression was applied using the least squares adjustment method. In total, 867 specimens were collected, representing four orders, ten families, and 12 species. The b coefficient of the length-weight regression ranged from 2.58 to 3.22, and r2 from 0.77 to 0.99. Five species had negative allometric growth (b < 3), six had isometric (b = 3), and one had positive allometric growth (b > 3). The length-weight relationship was documented for the first time in 10 of the 12 species – Chrysobrycon hesperus, Knodus smithi, Phenacogaster pectinata, Carnegiella myersi, Pyrrhulina obermulleri, Gymnotus curupira, Brachyhypopomus sullivani, Corydoras cervinus, Denticetopsis seducta, and Bujurquina syspilus. Our results contribute to the knowledge on life cycle parameters of fish species from the Southwestern Amazon. Resumo Analisamos as relações peso-comprimento de 12 espécies de peixes pouco conhecidas amostradas em quatro igarapés de terra-firme no sudoeste da Amazônia, no estado do Acre, Brasil. As amostragens diurnas e noturnas ocorreram em março e novembro de 2017. No total, foram coletados 867 exemplares, representando quatro ordens, dez famílias e 12 espécies. O coeficiente b da regressão peso-comprimento variou de 2,58 a 3,22, e o r2 de 0,77 a 0,99. Cinco espécies tiveram crescimento alométrico negativo (b < 3), seis tiveram crescimento isométrico (b = 3) e uma teve crescimento alométrico positivo (b > 3). A relação peso-comprimento foi documentada pela primeira vez em 10 das 12 espécies – Chrysobrycon hesperus, Knodus smithi, Phenacogaster pectinata, Carnegiella myersi, Pyrrhulina obermulleri, Gymnotus curupira, Brachyhypopomus sullivani, Corydoras cervinus, Denticetopsis seducta e Bujurquina syspilus. Nossos resultados contribuem para o conhecimento dos parâmetros do ciclo de vida de espécies de peixes do sudoeste da Amazônia.

Despite increasing efforts in recent years to catalog the fish diversity of Amazonian rivers, many regions are still under-sampled, and sandy beach environments are particularly poorly understood. The present study focused on a 300 km stretch of the Acre river, in the southwestern Amazon basin, where we sampled 30 sandy beaches separated by a mean interval of 10 km. We collected 15,329 fish representing 80 species, 26 families, and nine orders. The Characiformes were the most abundant order, providing 88.24% of the individuals collected, followed by the Siluriformes, with 10.03%, while the Siluriformes had the highest species richness, with 37 species (45.0%), followed by the Characiformes, with 30 (37.5%). The most abundant species were the characiforms Knodus orteguasae and Creagruto barrigai. Reliable data on a region’s biota is fundamental for the evaluation of patterns of biodiversity, and the occurrence and management of threatened species. As fish are directly affected by pollutants and the degradation of aquatic environments, further research in areas that are still poorly sampled will be essential for the elaboration of effective conservation strategies. Resumo: Apesar dos crescentes esforços para catalogar a diversidade de peixes nos rios amazônicos, muitas regiões ainda estão sub-amostradas e os ambientes de praias arenosas são particularmente pouco compreendidos. Este estudo foi realizado ao longo de um trecho de 300 km do Rio Acre, no sudoeste da bacia amazônica, onde foram amostradas 30 praias, separadas por uma distância média de 10 km. Foram coletados 15.329 peixes, representados em 80 espécies, 26 famílias e nove ordens. Characiformes foi a ordem mais abundante, representando 88,24% dos indivíduos coletados, seguidos pelos Siluriformes, com 10,03%, enquanto os Siluriformes apresentaram a maior riqueza, com 37 espécies (45,0%), seguidas pelos Characiformes, com 30 espécies (37,5%). As espécies mais abundantes foram os characiformes Knodus orteguasae e Creagruto barrigai. Dados confiáveis sobre a biota de uma região são fundamentais para a avaliação dos padrões de biodiversidade e conhecimento sobre a ocorrência e manejo de espécies ameaçadas. Como os peixes são diretamente afetados por poluentes e pela degradação dos ambientes aquáticos, mais pesquisas em áreas que ainda são pouco amostradas serão essenciais para a elaboração de estratégias eficazes de conservação.