Early Recurrence and Cerebral Bleeding in Patients With Acute Ischemic Stroke and Atrial Fibrillation: effect of Anticoagulation and Its Timing: the RAF Study.

BACKGROUND AND PURPOSE: The best time for administering anticoagulation therapy in acute cardioembolic stroke remains unclear. This prospective cohort study of patients with acute stroke and atrial fibrillation, evaluated (1) the risk of recurrent ischemic event and severe bleeding; (2) the risk factors for recurrence and bleeding; and (3) the risks of recurrence and bleeding associated with anticoagulant therapy and its starting time after the acute stroke. METHODS: The primary outcome of this multicenter study was the composite of stroke, transient ischemic attack, symptomatic systemic embolism, symptomatic cerebral bleeding and major extracranial bleeding within 90 days from acute stroke. RESULTS: Of the 1029 patients enrolled, 123 had 128 events (12.6%): 77 (7.6%) ischemic stroke or transient ischemic attack or systemic embolism, 37 (3.6%) symptomatic cerebral bleeding, and 14 (1.4%) major extracranial bleeding. At 90 days, 50% of the patients were either deceased or disabled (modified Rankin score ≥3), and 10.9% were deceased. High CHA2DS2-VASc score, high National Institutes of Health Stroke Scale, large ischemic lesion and type of anticoagulant were predictive factors for primary study outcome. At adjusted Cox regression analysis, initiating anticoagulants 4 to 14 days from stroke onset was associated with a significant reduction in primary study outcome, compared with initiating treatment before 4 or after 14 days: hazard ratio 0.53 (95% confidence interval 0.30-0.93). About 7% of the patients treated with oral anticoagulants alone had an outcome event compared with 16.8% and 12.3% of the patients treated with low molecular weight heparins alone or followed by oral anticoagulants, respectively (P=0.003). CONCLUSIONS: Acute stroke in atrial fibrillation patients is associated with high rates of ischemic recurrence and major bleeding at 90 days. This study has observed that high CHA2DS2-VASc score, high National Institutes of Health Stroke Scale, large ischemic lesions, and type of anticoagulant administered each independently led to a greater risk of recurrence and bleedings. Also, data showed that the best time for initiating anticoagulation treatment for secondary stroke prevention is 4 to 14 days from stroke onset. Moreover, patients treated with oral anticoagulants alone had better outcomes compared with patients treated with low molecular weight heparins alone or before oral anticoagulants.

Length of the Mitral Isthmus But Not Anatomical Location of Ablation Line Predicts Bidirectional Mitral Isthmus Block in Patients Undergoing Catheter Ablation of Persistent Atrial Fibrillation: A Randomized Controlled Trial.

INTRODUCTION: Mitral isthmus (MI) ablation is an effective option in patients undergoing ablation for persistent atrial fibrillation (AF). Achieving bidirectional conduction block across the MI is challenging, and predictors of MI ablation success remain incompletely understood. We sought to determine the impact of anatomical location of the ablation line on the efficacy of MI ablation. METHODS AND RESULTS: A total of 40 consecutive patients (87% male; 54 ± 10 years) undergoing stepwise AF ablation were included. MI ablation was performed in sinus rhythm. MI ablation was performed from the left inferior PV to either the posterior (group 1) or the anterolateral (group 2) mitral annulus depending on randomization. The length of the MI line (measured with the 3D mapping system) and the amplitude of the EGMs at 3 positions on the MI were measured in each patient. MI block was achieved in 14/19 (74%) patients in group 1 and 15/21 (71%) patients in group 2 (P = NS). Total MI radiofrequency time (18 ± 7 min vs. 17 ± 8 min; P = NS) was similar between groups. Patients with incomplete MI block had a longer MI length (34 ± 6 mm vs. 24 ± 5 mm; P < 0.001), a higher bipolar voltage along the MI (1.75 ± 0.74 mV vs. 1.05 ± 0.69 mV; P < 0.01), and a longer history of continuous AF (19 ± 17 months vs. 10 ± 10 months; P < 0.05). In multivariate analysis, decreased length of the MI was an independent predictor of successful MI block (OR 1.5; 95% CI 1.1-2.1; P < 0.05). CONCLUSIONS: Increased length but not anatomical location of the MI predicts failure to achieve bidirectional MI block during ablation of persistent AF.

L'anticoagulation du patient âgé en fibrillation atriale: que prescrivent les cardiologues, les gériatres et les médecins généralistes [Anticoagulation in the aged patient with atrial fibrillation: What are prescribing cardiologists, geriatricians and general practitioners?].

OBJECTIVE: To assess prescribing of anticoagulants in atrial fibrillation (AF) in the elderly, both a quantitative point of view (rate of anticoagulation) and qualitative (type of anticoagulation). Determinants of prescribing and non-prescribing were also analysed. METHODS: Prospective survey of practice, based on one clinical case and questionnaire conducted in 60 practitioners (20 cardiologists [C], 20 geriatricians [G] and 20 general practitioners [GP]). RESULTS: In reading the clinical case, 88.3% of physicians would have initiated a treatment; three types of treatments would have been chosen: AVK (68.3%), ODA (20.0%) and platelet antiaggregant (11.7%). Criteria taken into account to initiate anticoagulation varied according to the specialty. Cardiologists considered more the age criteria (C: 95.0%, G: 75.0%, MG: 60.0%; P<0.05), diabetes (C: 90.0%, G: 60.0%, MG: 55.0%; P<0.05), hypertension (C: 85.0%, G: 55.0%, MG: 60.0%; P<0.05) and female gender (C: 80.0%, G: 35.0%, MG: 25.0%; P<0.05). The quality of renal function was however a more secondary criteria (C: 15.0%, G: 5.0%, MG: 0.0%; P<0.05). General practitioners considered most frequently the presence of underlying heart disease (C: 35.0%, G: 5.0%, MG: 45.0%; P<0.05) as well as usual cardiovascular risk factors (overweight, dyslipidaemia; P<0.05). Risk of bleeding, however, was observed by 76.7% of physicians in the clinical situation presented (C: 70.0%, G: 75.0%, MG: 85.0%; P<0.05). CONCLUSION: This survey confirms that the FA remains under anticoagulated in the elderly and the barriers to the prescription of oral anticoagulation are often without rational basis.

Monitoring spatial and temporal dynamics of bird communities in Mediterranean landscapes affected by largewildfires = Seguimiento de la dinámica espacial y temporal de comunidades de aves en paisajes mediterráneos afectados por grandes fuegos

We presented a bird-monitoring database inMediterranean landscapes (Catalonia, NE Spain) affected by wildfires and we evaluated: 1) the spatial and temporal variability in the bird community composition and 2) the influence of pre-fire habitat configuration in the composition of bird communities. The DINDIS database results fromthemonitoring of bird communities occupying all areas affected by large wildfires in Catalonia since 2000.We used bird surveys conducted from 2006 to 2009 and performed a principal components analysis to describe two main gradients of variation in the composition of bird communities, which were used as descriptors of bird communities in subsequent analyses. We then analysed the relationships of these community descriptors with bioclimatic regions within Catalonia, time since fire and pre-fire vegetation (forest or shrubland).We have conducted 1,918 bird surveys in 567 transects distributed in 56 burnt areas. Eight out of the twenty most common detected species have an unfavourable conservation status, most of them being associated to open-habitats. Both bird communities’ descriptors had a strong regional component and were related to pre-fire vegetation, and to a lesser extent to the time since fire.We came to the conclusion that the responses of bird communities to wildfires are heterogeneous, complex and context dependent. Large-scale monitoring datasets, such as DINDIS, might allow identifying factors acting at different spatial and temporal scales that affect the dynamics of species and communities, giving additional information on the causes under general trends observed using other monitoring systems

Motilidade esofagiana: ensaio iconográfico sobre cintilografia dinâmica do esôfago

Este trabalho é uma seleção interessante de imagens dinâmicas do esôfago e de curvas de atividade/tempo, variando da motilidade normal até o extremo oposto, a acalásia em estado avançado. A técnica é a usual: quatro horas de jejum, com restrição de fumo, álcool e cafeína; incidência anterior; imagens de 0,5 segundo durante dois minutos, região da boca ao fundo gástrico, seguida de imagem plana de 20 segundos da mesma região (tempo de trânsito normal: < 10 segundos). A coletânea é baseada em vinte anos de experiência empregando uma sistematização com vários parâmetros de análise que permite discriminar pacientes com tempo total de trânsito normal.

Initiation of rivaroxaban in patients with nonvalvular atrial fibrillation at the primary care level: the Swiss Therapy in Atrial Fibrillation for the Regulation of Coagulation (STAR) Study.

BACKGROUND: Rivaroxaban has become an alternative to vitamin-K antagonists (VKA) for stroke prevention in non-valvular atrial fibrillation (AF) patients due to its favourable risk-benefit profile in the restrictive setting of a large randomized trial. However in the primary care setting, physician's motivation to begin with rivaroxaban, treatment satisfaction and the clinical event rate after the initiation of rivaroxaban are not known. METHODS: Prospective data collection by 115 primary care physicians in Switzerland on consecutive nonvalvular AF patients with newly established rivaroxaban anticoagulation with 3-month follow-up. RESULTS: We enrolled 537 patients (73±11years, 57% men) with mean CHADS2 and HAS-BLED-scores of 2.2±1.3 and 2.4±1.1, respectively: 301(56%) were switched from VKA to rivaroxaban (STR-group) and 236(44%) were VKA-naïve (VN-group). Absence of routine coagulation monitoring (68%) and fixed-dose once-daily treatment (58%) were the most frequent criteria for physicians to initiate rivaroxaban. In the STR-group, patient's satisfaction increased from 3.6±1.4 under VKA to 5.5±0.8 points (P<0.001), and overall physician satisfaction from 3.9±1.3 to 5.4±0.9 points (P<0.001) at 3months of rivaroxaban therapy (score from 1 to 6 with higher scores indicating greater satisfaction). In the VN-group, both patient's (5.4±0.9) and physician's satisfaction (5.5±0.7) at follow-up were comparable to the STR-group. During follow-up, 1(0.19%; 95%CI, 0.01-1.03%) ischemic stroke, 2(0.37%; 95%CI, 0.05-1.34%) major non-fatal bleeding and 11(2.05%; 95%CI, 1.03-3.64%) minor bleeding complications occurred. Rivaroxaban was stopped in 30(5.6%) patients, with side effects being the most frequent reason. CONCLUSION: Initiation of rivaroxaban for patients with nonvalvular AF by primary care physicians was associated with a low clinical event rate and with high overall patient's and physician's satisfaction.

Consistency of safety and efficacy of new oral anticoagulants across subgroups of patients with atrial fibrillation.

AIMS: The well-known limitations of vitamin K antagonists (VKA) led to development of new oral anticoagulants (NOAC) in non-valvular atrial fibrillation (NVAF). The aim of this meta-analysis was to determine the consistency of treatment effects of NOAC irrespective of age, comorbidities, or prior VKA exposure. METHODS AND RESULTS: All randomized, controlled phase III trials comparing NOAC to VKA up to October 2012 were eligible provided their results (stroke/systemic embolism (SSE) and major bleeding (MB)) were reported according to age (≤ or >75 years), renal function, CHADS2 score, presence of diabetes mellitus or heart failure, prior VKA use or previous cerebrovascular events. Interactions were considered significant at p <0.05. Three studies (50,578 patients) were included, respectively evaluating apixaban, rivaroxaban, and dabigatran versus warfarin. A trend towards interaction with heart failure (p = 0.08) was observed with respect to SSE reduction, this being greater in patients not presenting heart failure (RR = 0.76 [0.67-0.86]) than in those with heart failure (RR = 0.90 [0.78-1.04]); Significant interaction (p = 0.01) with CHADS2 score was observed, NOAC achieving a greater reduction in bleeding risk in patients with a score of 0-1 (RR 0.67 CI 0.57-0.79) than in those with a score ≥2 (RR 0.85 CI 0.74-0.98). Comparison of MB in patients with (RR 0.97 CI 0.79-1.18) and without (RR 0.76 CI 0.65-0.88) diabetes mellitus showed a similar trend (p = 0.06). No other interactions were found. All subgroups derived benefit from NOA in terms of SSE or MB reduction. CONCLUSIONS: NOAC appeared to be more effective and safer than VKA in reducing SSE or MB irrespective of patient comorbidities. Thromboembolism risk, evaluated by CHADS2 score and, to a lesser extent, diabetes mellitus modified the treatment effects of NOAC without complete loss of benefit with respect to MB reduction.

Short-term heparin kinetics during catheter ablation of atrial fibrillation

CONTEXTE: L'ablation percutanée par cathéter de la fibrillation auriculaire (AC-FA) est une option de traitement pour les patients souffrant de fibrillation auriculaire (FA) symptomatique réfractaire au traitement médicamenteux. L'AC-FA comporte un risque de complications thromboemboliques qui a été réduit par l'utilisation de l'héparine non fractionnée (HNF) intraveineuse durant la procédure. L'administration optimale de l'HNF ainsi que sa cinétique ne sont pas bien établies et nécessitent d'être déterminées avec précision. MÉTHODES ET RÉSULTATS: Cette étude a inclus 102 patients consécutifs atteints de FA symptomatique, réfractaire au traitement médicamenteux, référés pour une AC-FA. L'âge moyen était de 61 ± 10 ans. Après une ponction transseptale de la fosse ovale, une injection intraveineuse de HNF ajustée au poids (100 U / kg) a été administré. Une augmentation significative du temps de coagulation activé (ACT) a été observée passant d'une valeur de base moyenne de 100 ± 27 secondes, à 355 ± 94 secondes à 10 minutes (T10) et à 375 ± 90 secondes à 20 minutes (T20). 24 patients n'ont pas atteint la valeur visée d'ACT > 300 secondes à T10 et plus de la moitié de ce collectif est resté avec les valeurs d'ACT infrathérapeutiques à T20. Ce sous-ensemble de patients avait des caractéristiques cliniques similaires et avait reçu des doses similaires d'HNF, mais s'était plus fréquemment fait prescrire de la vitamine Kl pré-procédurale que le reste de la population de l'étude. CONCLUSION: Au cours d'une intervention standard, l'HNF montre, de manière inattendue, une cinétique d'anticoagulation lente dans une proportion significative des procédures et ceci jusqu'à 20 minutes après l'administration. Ces résultats soutiennent l'importance d'une administration d'HNF avant la ponction transseptale ou tout cathétérisme gauche avec des mesures précoces et répétées d'ACT afin d'identifier les patients avec une cinétique retardée. Ils sont en ligne avec les directives récentes proposant d'effectuer l'AC-FA sous anticoagulation thérapeutique.

Elementos da dinâmica química ao nível da teoria variacional do estado de transição com correções interpoladas

In this article are presented some fundamental elements of the conventional and of the variational transition state theories which are needed to carried out calculations of semi-classical chemical dynamics. Some important bottlenecks in building reliable potential energy surfaces using electronic structure calculations are also discussed. It is put emphasis on the methodology of the variational transition state theory with interpolated corrections (VTST-IC), and its application in the calculations of the rate constants and of the kinetic isotope effect (KIE) of CH4 + Cl « CH3 + HCl reaction.

A dinâmica de analisar livros didáticos com os professores de química

This work evidences a survey conducted during a teacher professional qualification in Rio Grande do Sul, Brazil. This survey analysed the textbooks used by these teachers. The dynamics consisted of choosing the analytic criteria used by teachers, and adding new criteria for examining their difficulties and ways to choose textbooks. This article emphasises the problematics and difficulties teachers have to make choices and their loss of skills and authority to consider these books more profoundly.

Um potencial de interação para o estudo de materiais e simulações por dinâmica molecular

The Vashishta-Rahman effective interaction potential, based on the Pauling's concept of "ionic radii", has been successfully employed to investigate structural and dynamical properties of different classes of material. By celebrating Pauling's birth centenary, we review the building up of the Vashishta-Rahman potential and we present molecular-dynamics simulation results for structure and dynamics of superionic materials, chalcogenide glasses and metallic oxides.

Dinámica de reacciones unimoleculares en fase gas: Desviaciones del comportamiento estadístico

The present review summarizes the most relevant results of our research group obtained recently in the field of unimolecular reaction dynamics. The following processes are specifically analyzed: the isomerization, dissociation and elimination in methyl nitrite, the fragmentation reactions of the mercaptomethyl cation, the C-CO dissociation in the acetyl and propionyl radicals, and the decomposition of vinyl fluoride. In all the cases, only state- or energy-selected systems are considered. Special emphasis is paid to the possibility of systems exhibiting non-statistical behavior.