X-ray Diffraction Profiles Modeling Method for Layered Structures Reconstruction: Nanoclay Structural Verification

The nanoclay properties find a large environmental application domain as depolluant, ion exchanger, natural geological barrier for industrial and radioactive waste confinement, clay-based nanocomposite for drug delivery, and more. Layered materials, such as nanoclay, present rather complex structures whose classical characterization requires a complementarity between several analysis methods to decipher the effects of interstratification (and its cause) on the intrinsic functional properties. The appearance of defects related to the layers stacking mode, which differ in their thickness and/or their internal structure are directly related to the reactivity of the mineral’s surface. During the last decades, and with the development of computer codes, the modeling of X-ray diffraction profiles has proven to be an important tool that allows detailed structural reconstruction. The quantitative XRD analysis, which consists of the comparison of experimental (00l) reflections with the calculated ones deduced from structural models, allowed us to determine the optimal structural parameters describing interlamellar space (IS) configuration, hydration state, cation exchange capacity (CEC), layer stacking mode, and theoretical mixed-layer structure (MLS) distribution. This chapter will review the state of the art of this theoretical approach as a basic technique for the study of nanoclays. The basic mathematical formalism, the parameters affecting the theoretical models, and the modeling strategy steps will be detailed in concrete examples

Early repolarization electrocardiography pattern with unexplained syncope during training in a young black African non-elite athlete: An accidental finding?

Until recently it was generally thought that early repolarization is benign. But a recent article in the NEJM (Haissaguerre et al.) suggests that some persons with early repolarization may be at risk of life-threatening ventricular tachyarrhythmia. Unexplained syncope or sudden death occurs mostly during sleep. However, some cases of cardiac arrest during exertion have been reported. We report the case of a 39 year-old black African male with early repolarization pattern on electrocardiogram who regularly experienced dizziness (and one episode of transient loss of consciousness) exclusively while exercising. Detailed examination was normal. Under quinidine therapy, he experienced no further episodes. Increasingly reported cases of cardiac arrest in Africans, and significant prevalence of early repolarization in this population, have to be taken into account since the Haissaguerre et al. report. Further evidence of the lethal consequences of this syndrome are needed, bearing in mind that diagnostic tools for life-threatening arrhythmias are often scarce in sub-Saharan Africa

0328: Assessment of radiation exposure during cardiac device implantation: lessons learned from a multicenter registry

BackgroundFew data exist about radiation exposure during implantation of cardiac electrical device. No dose reference levels (DRLs) were reported.Purpose to define DRLs and to analyze factors related to an increased radiation dose delivered to patients and medical staff.Methods the Raypace study is a multicenter, prospective observational registry. Using a national database, patient demographic, procedural and radiation data were collected. Fluoroscopy time (FT) and dose-area product (DAP) were registered. Physician/staff exposure was measured using 2 real-time personal dosimeters, one worn under the lead apron and the other one worn outside the apron. Statistical analysis used log-transformation of DAP, FT and DAP/FT ratio.ResultsA total of 657 procedures from 9 institutions were reviewed. Pacemaker (PM) and cardioverter-defibrillator (ICD) implantation was performed in 481 and 176 patients, respectively. A cardiac resynchronization device was implanted in 153 patients. Fluoroscopy time was similar for PM and ICD implantations. Median fluoroscopy time was 836, 117 and 101 second and median DAP was 1410, 150 and 129 cGy.cm2 for biventricular, dual chamber and ventricular device implantation, respectively. LAO projection, in addition to AP projection, was used in 47% of the procedures. Five centers out of 9 used collimation. The median Hp (10) effective dose measured outside the lead apron was 4.6 µSv and 0.1 µSv under the lead apron.Regarding CRT implant procedures, four systems out of 6 were responsible for an increased exposure (p<0.001). DRLs were 2600, 338 and 332 cGy.cm2 for biventricular, dual chamber and ventricular device implantation, respectively.ConclusionsDAP reduction was improved with the use of latest generators but needed customized settings. Biventricular device implantation was responsible for the highest radiation exposure. However, radiation exposure during those procedures have decreased as compared to previously reported values

0107: Strategy of early detection and active management of supraventricular arrhythmia with remote monitoring: the randomized, multicenter SETAM trial

ObjectiveAtrial fibrillation (AF) is a common arrhythmia associated with increased risk of thromboembolic events or other complications. The French randomized, multicenter, SETAM trial assessed the impact of the home monitoring (HM) technology on detection and treatment of supra-ventricular arrhythmia (SVA).MethodsPatients (pts) implanted with a dual chamber pacemaker were enrolled in the study at hospital discharge if they had a sinusal rhythm at enrollment, no antiarrhythmic, anticoagulant or dual-antiplatelet therapy, and if they had a CHA2DS2-VASc score of 2 or more. The pts were randomly assigned to an active group (Act Gp), followed by Biotronik HM, or a control group (Cont Gp) without HM surveillance. The time from implantation to the first SVA-related intervention was compared between the 2 groups (primary endpoint).ResultsA total of 595 pts (mean age = 79±8 y.o, 63% male, mean CHA2DS2-VASc score = 3.7±1.2) were followed during 12.8±3.3Mo. The most prevalent co-morbidities were hypertension (82% pts), diabetes (29%) and vascular disease (24%). Implantation indications were atrio-ventricular blocks in 77% of pts, sinus node disease in 20% and others in 3%.The global SVA incidence was 25% (29% in the Act Gp vs 22% in the Cont Gp, p=ns).A therapy (drugs or ablation) was instituted for 49/291 pts (17%) in the Act Gp vs 43/304 pts (14%) in the Cont Gp (p=ns). The median time from implantation to the first therapy for SVA was 114 [44; 241] days in the Act Gp vs 224 [67; 366] days in the Cont Gp, representing a median gain of 110-days in SVA management (50% reduction, p=0.01). Over these 92 pts, 54 had AF (59%) and 38 had atrial flutter or tachyarrhythmia (41%). Anticoagulation was initiated in 80% of pts and antiarrhythmic drugs in 55%.ConclusionThe SETAM study demonstrated that HM allows earlier detection and treatment of SVA in pacemaker pts. The next step is to report how early detection of SVA with HM can possibly improve the patients clinical outcome

Patterns of oral anticoagulant use and outcomes in Asian patients with atrial fibrillation:a post-hoc analysis from the GLORIA-AF Registry

Background: Previous studies suggested potential ethnic differences in the management and outcomes of atrial fibrillation (AF). We aim to analyse oral anticoagulant (OAC) prescription, discontinuation, and risk of adverse outcomes in Asian patients with AF, using data from a global prospective cohort study. Methods: From the GLORIA-AF Registry Phase II–III (November 2011–December 2014 for Phase II, and January 2014–December 2016 for Phase III), we analysed patients according to their self-reported ethnicity (Asian vs. non-Asian), as well as according to Asian subgroups (Chinese, Japanese, Korean and other Asian). Logistic regression was used to analyse OAC prescription, while the risk of OAC discontinuation and adverse outcomes were analysed through Cox-regression model. Our primary outcome was the composite of all-cause death and major adverse cardiovascular events (MACE). The original studies were registered with ClinicalTrials.gov, NCT01468701, NCT01671007, and NCT01937377. Findings: 34,421 patients were included (70.0 ± 10.5 years, 45.1% females, 6900 (20.0%) Asian: 3829 (55.5%) Chinese, 814 (11.8%) Japanese, 1964 (28.5%) Korean and 293 (4.2%) other Asian). Most of the Asian patients were recruited in Asia (n = 6701, 97.1%), while non-Asian patients were mainly recruited in Europe (n = 15,449, 56.1%) and North America (n = 8378, 30.4%). Compared to non-Asian individuals, prescription of OAC and non-vitamin K antagonist oral anticoagulant (NOAC) was lower in Asian patients (Odds Ratio [OR] and 95% Confidence Intervals (CI): 0.23 [0.22–0.25] and 0.66 [0.61–0.71], respectively), but higher in the Japanese subgroup. Asian ethnicity was also associated with higher risk of OAC discontinuation (Hazard Ratio [HR] and [95% CI]: 1.79 [1.67–1.92]), and lower risk of the primary composite outcome (HR [95% CI]: 0.86 [0.76–0.96]). Among the exploratory secondary outcomes, Asian ethnicity was associated with higher risks of thromboembolism and intracranial haemorrhage, and lower risk of major bleeding. Interpretation: Our results showed that Asian patients with AF showed suboptimal thromboembolic risk management and a specific risk profile of adverse outcomes; these differences may also reflect differences in country-specific factors. Ensuring integrated and appropriate treatment of these patients is crucial to improve their prognosis. Funding: The GLORIA-AF Registry was funded by Boehringer Ingelheim GmbH.</p

Validating the predictive ability of the 2MACE score for major adverse cardiovascular events in patients with atrial fibrillation:results from phase II/III of the GLORIA-AF registry

The 2MACE score was specifically developed as a risk-stratification tool in atrial fibrillation (AF) to predict cardiovascular outcomes. We evaluated the predictive ability of the 2MACE score in the GLORIA-AF registry. All eligible patients from phase II/III of the prospective global GLORIA-AF registry were included. Major adverse cardiac events (MACEs) were defined as the composite outcome of stroke, myocardial infarction and cardiovascular death. Cox proportional hazards were used to examine the relationship between the 2MACE score and study outcomes. Predictive capability of the 2MACE score was investigated using receiver-operating characteristic curves. A total of 25,696 patients were included (mean age 71 years, female 44.9%). Over 3 years, 1583 MACEs were recorded. Patients who had MACE were older, with more cardiovascular risk factors and were less likely to be managed using a rhythm-control strategy. The median 2MACE score in the MACE and non-MACE groups were 2 (IQR 1–3) and 1 (IQR 0–2), respectively (p &lt; 0.001). The 2MACE score was positively associated with an increase in the risk of MACE, with a score of ≥ 2 providing the best combination of sensitivity (69.6%) and specificity (51.6%), HR 2.47 (95% CI, 2.21–2.77). The 2MACE score had modest predictive performance for MACE in patients with AF (AUC 0.655 (95% CI, 0.641–0.669)). Our analysis in this prospective global registry demonstrates that the 2MACE score can adequately predict the risk of MACE (defined as myocardial infarction, CV death and stroke) in patients with AF. Clinical trial registration: http://www.clinicaltrials.gov . Unique identifiers: NCT01468701, NCT01671007 and NCT01937377

Anticoagulant selection in relation to the SAMe-TT₂R₂ score in patients with atrial fibrillation:The GLORIA-AF registry

Aim: The SAMe-TT2R2 score helps identify patients with atrial fibrillation (AF) likely to have poor anticoagulation control during anticoagulation with vitamin K antagonists (VKA) and those with scores &gt;2 might be better managed with a target-specific oral anticoagulant (NOAC). We hypothesized that in clinical practice, VKAs may be prescribed less frequently to patients with AF and SAMe-TT2R2 scores &gt;2 than to patients with lower scores. Methods and results: We analyzed the Phase III dataset of the Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF), a large, global, prospective global registry of patients with newly diagnosed AF and ≥1 stroke risk factor. We compared baseline clinical characteristics and antithrombotic prescriptions to determine the probability of the VKA prescription among anticoagulated patients with the baseline SAMe-TT2R2 score &gt;2 and ≤ 2. Among 17,465 anticoagulated patients with AF, 4,828 (27.6%) patients were prescribed VKA and 12,637 (72.4%) patients an NOAC: 11,884 (68.0%) patients had SAMe-TT2R2 scores 0-2 and 5,581 (32.0%) patients had scores &gt;2. The proportion of patients prescribed VKA was 28.0% among patients with SAMe-TT2R2 scores &gt;2 and 27.5% in those with scores ≤2. Conclusions: The lack of a clear association between the SAMe-TT2R2 score and anticoagulant selection may be attributed to the relative efficacy and safety profiles between NOACs and VKAs as well as to the absence of trial evidence that an SAMe-TT2R2-guided strategy for the selection of the type of anticoagulation in NVAF patients has an impact on clinical outcomes of efficacy and safety. The latter hypothesis is currently being tested in a randomized controlled trial. Clinical trial registration: URL: https://www.clinicaltrials.gov//Unique identifier: NCT01937377, NCT01468701, and NCT01671007.</p