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In repaired tetralogy of Fallot (TOF), little is known about characteristics of patients with rapid ventricular tachycardia (VT). Also, whether patients with a first episode of nonrapid VT may subsequently develop rapid VT or ventricular fibrillation (VF) has not been addressed.The objectives of this study were to compare patients with rapid VT/VF with those with nonrapid VT and to assess the evolution of VT cycle lengths (VTCLs) overtime.Data were analyzed from a nationwide registry including all patients with TOF and implantable cardioverter-defibrillator (ICD) since 2000. Patients with ≥1 VT episode with VTCL ≤250 ms (240 beats/min) formed the rapid VT/VF group.Of 144 patients (mean age 42.0 ± 12.7 years; 104 [72%] men), 61 (42%) had at least 1 VT/VF episode, including 28 patients with rapid VT/VF (46%), during a median follow-up of 6.3 years (interquartile range 2.2-10.3 years). Compared with patients in the nonrapid VT group, those in the rapid VT/VF group were significantly younger at ICD implantation (35.2 ± 12.6 years vs 41.5 ± 11.2 years; P = .04), had more frequently a history of cardiac arrest (8 [29%] vs 2 [6%]; P = .02), less frequently a history of atrial arrhythmia (11 [42%] vs 22 [69%]; P = .004), and higher right ventricular ejection fraction (43.3% ± 10.3% vs 36.6% ± 11.2%; P = .04). The median VTCL of VT/VF episodes was 325 ms (interquartile range 235-429 ms). None of the patients with a first documented nonrapid VT episode had rapid VT/VF during follow-up.Patients with TOF and rapid VT/VF had distinct clinical characteristics. The relatively low variation of VTCL over time suggests a room for catheter ablation without a backup ICD in selected patients with well-tolerated VT.Clinicaltrials.gov identifier: NCT03837574.

To compare the two different ablation strategies, both guided by the Ablation Index (AI), in the setting of atrial fibrillation (AF) ablation: high-power short-duration (HPSD) ablation using 40 W on the posterior wall and 50 W elsewhere versus low-power long-duration (LPLD) using 25 W posteriorly and 35 W elsewhere.Prospective, multicenter nonrandomized, noninferiority study of consecutive patients referred for paroxysmal AF ablation from January 2018 to July 2019. Ablation was guided by the AI (≥500 for anterior segments, ≥450 for the roof and inferior segments and 400 posteriorly) and an interlesion distance (ILD) ≤ 6 mm. Patients were separated into two groups: HPSD vs LPLD. Acute reconnection (after adenosine trial) and 2-year outcomes were assessed.160 patients (61% males, median age of 62 [IQR 51-69] years), fulfilled the study inclusion criteria - 80 patients (316 pulmonary veins [PV]) in the HPSD group and 80 patients (314 PV) in the LPLD. The probability of acute PV reconnection was similar between both groups: 2.2% in HPSD, 95%CI 0.6% to 3.8% vs. 3.4% in LPLD, 95%CI 1.4% to 5.4%; p 0.001 for noninferiority. Median PV ablation time (20 min vs 30 min, p 0.01) and procedure duration (80 min vs 100 min, p 0.001) were shorter in the HPSD group. After a median follow-up of 26 months, arrhythmia recurrence was similar between groups (17.5% in HPSD group vs. 18.8% in LPLD group, p = 0.79).In paroxysmal AF patients treated with the Ablation Index, a HPSD strategy is noninferior to the more standard LPLD ablation, while allowing for quicker procedures with shorter ablation times.

Since the widespread availability of contact-force sensing catheters, the need for a waiting period after pulmonary vein isolation (PVI) has not been reassessed. We aim to evaluate whether a waiting period is still necessary after PVI guided by the ablation Index (AI).Prospective, multicenter, randomized study of consecutive patients referred for paroxysmal atrial fibrillation (AF) ablation from May 2019 to February 2020. Patients were randomized in a 1:1 ratio to PVI with versus without a waiting period of 20 min. Acute pulmonary vein (PV) reconnection after adenosine challenge was the primary endpoint. A per-protocol analysis was designed to determine whether a strategy of dismissing the waiting period after PVI was noninferior to waiting for 20 min for identifying acute PV reconnection. PVI was guided by tailored AI values and an interlesion distance ≤6 mm.During the enrollment period, 167 patients (56% males, mean age of 57 ± 14 years) fulfilled the study inclusion criteria - 84 patients (308 PV) in the waiting period group (Group A) and 83 patients (314 PV) in the group without a waiting period (Group B). Acute PV reconnection was identified in 3.8% (95% confidence interval [CI], 1.7%-5.9%) of PVs in the study group B compared to 2.9% (95% CI, 1.0%-4.8%) of PVs in the Group A (p = .002 for non-inferiority). At 1-year follow-up, there was no significant difference in arrhythmia recurrence between groups (9.5% in Group A vs. 9.6% in Group B, hazard ratio: 1.03 [95% CI, 0.39-2.73], p = .98).In paroxysmal AF patients submitted to ablation, a tailored PVI guided by the AI rendered a 20-min waiting period unnecessary.

Background: Recurrences of atrial fibrillation (AF) after pulmonary vein isolation (PVI) are mainly due to pulmonary vein reconnection. However, a growing number of patients have AF recurrences despite durable PVI. The optimal ablative strategy for these patients is unknown. We analyzed the impact of current ablation strategies in a large multicenter study. Methods: Patients undergoing a redo ablation for AF and presenting durable PVI were included. The freedom from atrial arrhythmia after pulmonary vein-based, linear-based, electrogram-based, and trigger-based ablation strategies were compared. Results: Between 2010 and 2020, 367 patients (67% men, 63±10 years, 44% paroxysmal) underwent a redo ablation for AF recurrences despite durable PVI at 39 centers. After durable PVI was confirmed, linear-based ablation was performed in 219 (60%) patients, electrogram-based ablation in 168 (45%) patients, trigger-based ablation in 101 (27%) patients, and pulmonary vein-based ablation in 56 (15%) patients. Seven patients (2%) did not undergo any additional ablation during the redo procedure. After 22±19 months of follow-up, 122 (33%) and 159 (43%) patients had a recurrence of atrial arrhythmia at 12 and 24 months, respectively. No significant difference in arrhythmia-free survival was observed between the different ablation strategies. Left atrial dilatation was the only independent factor associated with arrhythmia-free survival (HR, 1.59 [95% CI, 1.13–2.23]; P =0.006). Conclusions: In patients with recurrent AF despite durable PVI, no ablation strategy used alone or in combination during the redo procedure appears to be superior in improving arrhythmia-free survival. Left atrial size is a significant predictor of ablation outcome in this population.

The LiCl-KCl molten salts method has been used in order to intercalate strontium into graphite. Combination of X-Ray Diffraction (XRD) experiments and ion beam analyses attests the obtaining of a monophasic sample. Its chemical composition corresponds to the Li 0.2 K 0.6 Sr 0.4 C 6 formula, revealing the synthesis of a quaternary Graphite Intercalation Compound (GIC), in agreement with the high repeat distance of 640 pm determined from its 00 l XRD and with the 1D electronic density profile. The very high-quality data obtained by hk 0 diffraction and rotating crystal method lead to a 2D organization of the intercalated sheet described by a large hexagonal unit cell containing 78 carbon atoms. Such quaternary phase including simultaneously alkali and alkaline-earth metals is unique and can only be prepared from molten salts method, opening new perspectives concerning graphite-based two-dimensional materials.

Pulmonary vein isolation (PVI) is effective at treating 50% of unselected patients with persistent atrial fibrillation (AF). Alternatively, PVI combined with a new ablation strategy entitled the Marshall-PLAN ensures a 78% 1-year sinus rhythm (SR) maintenance rate in the same population. However, a substantial subset of patients could undergo the Marshall-PLAN unnecessarily. It is therefore essential to identify those patients who can be treated with PVI alone versus those who may truly benefit from the Marshall-PLAN before ablation is performed. In this context, we hypothesized that electrical cardioversion (EC) could help to select the most appropriate strategy for each patient.In this multicentre, prospective, randomized study, patients with AF recurrence within 4 weeks after EC will be randomized 1:1 to PVI alone or the Marshall-PLAN. Conversely, patients in whom SR is maintained for ≥4 weeks after EC will be treated with PVI only and included in a prospective registry. The primary endpoint will be the 1-year SR maintenance rate after a single ablation procedure.The Marshall-PLAN might be necessary in patients with an advanced degree of persistent AF (i.e., where SR is not maintained for ≥4 uninterrupted weeks after EC). Conversely, in patients with mild or moderate persistent AF (i.e., where SR is maintained for ≥4 weeks after EC), PVI alone might be a sufficient ablation strategy. The PACIFIC trial is the first study designed to assess whether rhythm monitoring after EC could help to identify patients who should undergo adjunctive ablation strategies beyond PVI.

International audience; The synthesis of a novel first stage GIC containing simultaneously lithium, potassium and barium through a solid–liquid reaction by molten salts method is described. Such a route has been largely developed in our laboratory for intercalation of metals into graphite. The interplanar distance of this quaternary compound reaches 950 pm and exhibits poly-layered intercalated sheets defined by X-ray measurements. The Li0.2K0.75Ba0.6C6 chemical formula of the compound is determined by ion beam analysis and this GIC is remarkably homogeneous. This GIC is the first poly-layered one containing barium.

Background: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, and sudden cardiac death represents an important mode of death in these patients. Data evaluating the implantable cardioverter defibrillator (ICD) in this patient population remain scarce. Methods: A Nationwide French Registry including all patients with tetralogy of Fallot with an ICD was initiated in 2010 by the French Institute of Health and Medical Research. The primary time to event end point was the time from ICD implantation to first appropriate ICD therapy. Secondary outcomes included ICD-related complications, heart transplantation, and death. Clinical events were centrally adjudicated by a blinded committee. Results: A total of 165 patients (mean age, 42.2±13.3 years, 70.1% males) were included from 40 centers, including 104 (63.0%) in secondary prevention. During a median (interquartile range) follow-up of 6.8 (2.5–11.4) years, 78 (47.3%) patients received at least 1 appropriate ICD therapy. The annual incidence of the primary outcome was 10.5% (7.1% and 12.5% in primary and secondary prevention, respectively; P =0.03). Overall, 71 (43.0%) patients presented with at least 1 ICD complication, including inappropriate shocks in 42 (25.5%) patients and lead dysfunction in 36 (21.8%) patients. Among 61 (37.0%) patients in primary prevention, the annual rate of appropriate ICD therapies was 4.1%, 5.3%, 9.5%, and 13.3% in patients with, respectively, 0, 1, 2, or ≥3 guidelines-recommended risk factors. QRS fragmentation was the only independent predictor of appropriate ICD therapies (hazard ratio, 3.47 [95% CI, 1.19–10.11]), and its integration in a model with current criteria increased the 5-year time-dependent area under the curve from 0.68 to 0.81 ( P =0.006). Patients with congestive heart failure or reduced left ventricular ejection fraction had a higher risk of nonarrhythmic death or heart transplantation (hazard ratio, 11.01 [95% CI, 2.96–40.95]). Conclusions: Patients with tetralogy of Fallot and an ICD experience high rates of appropriate therapies, including those implanted in primary prevention. The considerable long-term burden of ICD-related complications, however, underlines the need for careful candidate selection. A combination of easy-to-use criteria including QRS fragmentation might improve risk stratification. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03837574.

International audience; Background: Women with congenital heart disease at high risk for sudden cardiac death have been poorly studied thus far.Objectives: The aim of this study was to assess sex-related differences in patients with tetralogy of Fallot (TOF) and implantable cardioverter-defibrillators (ICDs).Methods: Data were analyzed from the DAI-T4F (French National Registry of Patients With Tetralogy of Fallot and Implantable Cardioverter Defibrillator) cohort study, which has prospectively enrolled all patients with TOF with ICDs in France since 2010. Clinical events were centrally adjudicated by a blinded committee.Results: A total of 165 patients (mean age 42.2 ± 13.3 years) were enrolled from 40 centers, including 49 women (29.7%). Among the 9,692 patients with TOF recorded in the national database, the proportion of women with ICDs was estimated to be 1.1% (95% CI: 0.8%-1.5%) vs 2.2% (95% CI: 1.8%-2.6%) in men (P < 0.001). The clinical profiles of patients at implantation, including the number of risk factors for ventricular arrhythmias, were similar between women and men. During a median follow-up period of 6.8 years (IQR: 2.5-11.4 years), 78 patients (47.3%) received at least 1 appropriate ICD therapy, without significant difference in annual incidences between women (12.1%) and men (9.9%) (HR: 1.22; 95% CI: 0.76-1.97; P = 0.40). The risk for overall ICD-related complications was similar in women and men (HR: 1.33; 95% CI: 0.81-2.19; P = 0.30), with 24 women (49.0%) experiencing at least 1 complication.Conclusions: Our findings suggest that women with TOF at high risk for sudden cardiac death have similar benefit/risk balance from ICD therapy compared with men. Whether ICD therapy is equally offered to at-risk women vs men warrants further evaluation in TOF as well as in other congenital heart disease populations. (French National Registry of Patients With Tetralogy of Fallot and Implantable Cardioverter Defibrillator [DAI-T4F]; NCT03837574)

International audience; Objectives: This study aimed to assess the impact of pulmonary valve replacement (PVR) on ventricular arrhythmias burden in a population of tetralogy of Fallot (TOF) patients with continuous cardiac monitoring by implantable cardioverter-defibrillators (ICDs).Background: Sudden cardiac death is a major cause of death in TOF, and right ventricular overload is commonly considered to be a potential trigger for ventricular arrhythmias.Methods: Data were analyzed from a nationwide French ongoing study (DAI-T4F) including all TOF patients with an ICD since 2000. Survival data with recurrent events were used to compare the burden of appropriate ICD therapies before and after PVR in patients who underwent PVR over the study period.Results: A total of 165 patients (mean age 42.2 ± 13.3 years, 70.1% male) were included from 40 centers. Over a median follow-up period of 6.8 (interquartile range: 2.5 to 11.4) years, 26 patients (15.8%) underwent PVR. Among those patients, 18 (69.2%) experienced at least 1 appropriate ICD therapy. When considering all ICD therapies delivered before (n = 62) and after (n = 16) PVR, the burden of appropriate ICD therapies was significantly lower after PVR (HR: 0.21; 95% confidence interval [CI]: 0.08 to 0.56; p = 0.002). Respective appropriate ICD therapies rates per 100 person-years were 44.0 (95% CI: 35.7 to 52.5) before and 13.2 (95% CI: 7.7 to 20.5) after PVR (p < 0.001). In the overall cohort, PVR before ICD implantation was also independently associated with a lower risk of appropriate ICD therapy in primary prevention patients (HR: 0.29 [95% CI: 0.10 to 0.89]; p = 0.031).Conclusions: In this cohort of high-risk TOF patients implanted with an ICD, the burden of appropriate ICD therapies was significantly reduced after PVR. While optimal indications and timing for PVR are debated, these findings suggest the importance of considering ventricular arrhythmias in the overall decision-making process. (French National Registry of Patients With Tetralogy of Fallot and Implantable Cardioverter Defibrillator [DAI-T4F]; NCT03837574).

Introduction Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, and sudden cardiac death represents an important mode of death in these patients. Data evaluating the implantable cardioverter defibrillator (ICD) in this patient population remain scarce. Objective We aimed to describe long-term follow-up of TOF patients implanted with ICD through a nationwide French registry. Methods Nationwide French Registry including all TOF patients with an ICD initiated in 2010 by the French Institute of Health and Medical Research. The primary time to event endpoint was the time from ICD implantation to first appropriate ICD therapy. Clinical events were centrally adjudicated by a blinded committee. Results A total of 165 patients (mean age 42.2 ± 13.3 years, 70.1% males) were included from 40 centers, including 104 (63.0%) in secondary prevention. During a median (IQR) follow-up of 6.8 (2.5–11.4) years, 78 (47.3%) patients received at least one appropriate ICD therapy. The annual incidence of the primary outcome was 10.5% (7.1% and 12.5% in primary and secondary prevention, respectively, P = 0.03). Overall, 71 (43.0%) patients presented with at least one ICD complication, including inappropriate shocks in 42 (25.5%) patients and lead dysfunction in 36 (21.8%) patients. Among 61 (37.0%) primary prevention patients, the annual rate of appropriate ICD therapies was 4.1%, 5.3%, 9.5%, and 13.3% in patients with respectively no, one, two, or ≥ three guideline-recommended risk factors. QRS fragmentation was the only independent predictor of appropriate ICD therapies (HR 3.47, 95% CI 1.19–10.11), and its integration in a model with current criteria increased the 5-year time-dependent area under the curve from 0.68 to 0.81 (P = 0.006) ( Fig. 1 ). Conclusions Patients with TOF and an ICD experience high rates of appropriate therapies, including those implanted in primary prevention. The considerable long-term burden of ICD-related complications, however, underlines the need for careful candidate selection. A combination of easy-to-use criteria including QRS fragmentation might improve risk stratification.

Generally, it is possible to distinguish between object generalisation (or model-oriented generalisation, or data generalisation), which is intended to derive a geographical database, and cartographic generalisation, which aims at deriving a map or a cartographic data set. Currently, and since the end of the 1980s, research is characterised by attempts to go beyond the independent generalisation of geometry. Very briefly, the focus is now often put on the global generalisation process (generalisation operations formalising, generalisation process understanding and formalising and so forth), and on considering the spatial and semantic context of features and the geographical phenomena involved in the generalisation. Spatial conflict resolution is not the only problem in generalisation, but it is clearly crucial for the automation of generalisation. It is well known that the performances of most of the current generalisation algorithms, using existing hardware technology, are far from being compatible with ‘real-time’ computation needs.

International audience; Thanks to its lamellar structure, graphite can host various chemical species between its interplanar spaces to form Graphite Intercalation Compounds (GIC). Intercalation of metals into graphite can lead to remarkable modifications of the physical properties of the sample with respect to pristine graphite as for instance superconductivity. In this paper, we report attempts made to intercalate strontium, baryum and ytterbium into graphite, using a recent method involving a LiCl-KCl molten salt as a reaction medium. Resulting samples are characterized regarding their structure and chemical composition. We reveal the obtaining of bulk SrC$_6$ and BaC$_6$ and a superficial intercalation of ytterbium leading to superconducting YbC$_6$ domains only, as confirmed by dc-magnetization measurements.

Heavy alkali metal-arsenic alloys intercalate easily into graphite, leading to the formation of a new family of ternary graphite intercalation compounds (GICs). Pure phases formulated as MAsxC4s (M = K, Rb or Cs; s = stage; x ≤ 1) have been synthesized at the laboratory. This article aims to expose all physical measurements performed on these intercalation compounds to get an idea about their electronic properties. Electrical conductivity measurements have been performed both parallel and perpendicular to the basal planes, between 4.2 and 295 K. Room temperature resistivity values lie between 16 and 35 μΩ cm and the anisotropic resistivity takes a value of an order of magnitude of 10 4 . Dynamic magnetic susceptibility measurements, carried out at low temperature on some phases, showed that they do not exhibit superconducting transition up to 1.3 K. Raman spectroscopy investigation, which is a useful tool to study the electronic and the chemical stability of GICs, highlighted a significant up-shift of the G-band of the carbon intra-layer vibration frequency, compared to the pure graphite vibration mode. Undoubtedly, this is related to the electronic charge transfer established between graphite layers and intercalated species.

Background The electrocardiogram (ECG) is widely available and may contribute to a better risk stratification for sudden cardiac death in tetralogy of Fallot. Purpose To identify ECG predictors of appropriate therapies in patients with tetralogy of Fallot and implantable cardioverter defibrillator (ICD). Methods The DAI-T4F study is an ongoing national French registry including all patients with tetralogy of Fallot and ICD ( NCT03837574 ). Information have been collected prospectively since 2010. Cox proportional hazard models were used to identify factors associated with appropriate ICD therapies. Results A total of 134 patients (median age 41.7 years, 70.7% males) were enrolled. During a median (IQR) follow-up of 6.1 (2.7–10.2) years, 59 (44.0%) patients received at least one appropriate ICD therapy, giving annual incidence of 5.5% and 7.1% in primary and secondary prevention, respectively (P = 0.058). Overall, QRSd ≥ 180ms (P = 0.073), QRS fragmentation (P = 0.052), and QRS vector magnitude (vm, P = 0.327) were not significantly associated with appropriate ICD therapies, whereas the association of QRSd ≥ 180ms and QRS fragmentation (HR = 1.9, 95% CI: 1.1–3.4, P = 0.036) were associated with an increased risk of appropriates ICD therapies. In patients with ICD for primary prevention (47 patients, 35.1%), while non-sustained ventricular tachycardia (NSVT) considered isolated was not associated with events during follow-up (P = 0.069), combinations with QRSd ≥ 180 ms (HR = 7.2, 95% CI: 1.6–32.7, P = 0.011), QRS fragmentation (HR = 3.8, 95% CI: 1.2–12.4, P = 0.025), or decreased QRS vm (HR = 3.6, 95% CI: 1.1–12.1, P = 0.042) were all associated with a higher incidence of appropriate ICD therapies. Conclusions Our findings highlight that cumulative risk score derived from ECG may contribute to improve risk stratification in patients with tetralogy of Fallot, in particular QRS fragmentation and QRS vm in association with QRS duration and other traditional risk factors.

International audience

International audience; A new synthesis method using molten salts has been achieved allowing the intercalation of metals (e.g europium) into graphite. This method consists in dissolving various metals in a LiCl-KCl medium intended to be intercalated. In this work, many reactions are carried out by dissolving metals of first and second columns of the periodic table (Li, Na, K, Mg, Ca, Sr, Ba) in the molten salts before performing intercalation reactions for periods ranging from few minutes to several days and for temperatures included between 400 and 450 °C. The obtained compounds are then characterized by X-ray diffraction. Three different behaviors have been observed. With alkali metals, the obtained GIC is systematically LiC6 GIC. Magnesium leads to a sample of pure graphite remaining pristine. In case of alkaline earth metals, calcium, strontium and barium, the intercalation of the metal is systematically observed. The method presented in this paper reports for the first time the synthesis of a bulk SrC6 GIC. Finally, the intercalation mechanism using this medium has been deduced from these results and thanks to a study performed by ex situ X-ray diffraction in the case of the formation of the EuC6 GIC.

International audience; The intercalation of gold into graphite has been achieved thanks to a solid-liquid method using potassium metal-based molten alloys. Numerous syntheses have been performed varying the reactive alloy composition, the reaction temperature and the reaction time. The optimization of these parameters allowed to synthesize three novel ternary graphite intercalation compounds (GIC) containing poly-layered intercalated sheets, called alpha, beta and gamma. Thanks to a specific X-Ray diffraction study, the c-axis stacking sequence of the three compounds was determined. The a-GIC, which is a metastable compound, contains mixed potassium and gold two-layered intercalated sheets. The b-GIC and g-GIC contain very thick well ordered threelayered and five-layered sheets respectively. The very high repeat distances of the latter compounds are clearly explained by the amount of intercalated metals, precisely determined using nuclear microprobe analyses.

Intercalation reaction occurs when an excess of a liquid heavy alkali metal-arsenic alloy is contacted with a graphite sample under vacuum. This leads to the formation of several novel ternary phases. X-ray structural analysis was conducted to determine how intercalated metallic alloy is arranged between the graphitic layers. The results have shown that these phases are composed of poly6layered sheets alternately stacked with carbon layers along the c-axis. In addition, these layers are perfectly ordered with respect to the adjacent carbon planes. Two-dimensional super-lattices have been recorded and analyzed. The electrical conductivity has been studied both parallel and perpendicular to the basal planes, between 4.2 and 295 K. The basal-plane behavior is metallic, but the c-axis resistivity displays very high resistivity. The room temperature anisotropy is of the order of 104, which increases for some phases, by more than one order of magnitude at 4.2 K.

International audience; A ternary graphite-potassium-gold compound K1.3Au1.5C4 was synthesized by immersing a pyrographite platelet in various potassium metal-based molten alloys. Numerous reaction parameters were investigated (duration, temperature, composition of the alloy) in order to determine the stability conditions of the ternary compound. Using complementary X-ray diffraction and ion beam analysis experiments, the optimal conditions of preparation of this compound have been pointed out. The composition and homogeneity were evidenced by ion beam analysis and X-ray diffraction allowed to determine its repeat distance (1311pm) and its c-axis stacking sequence (K-Au-Au-Au-K). The 2D unit cell observed thanks to Transmission Electron Microscopy (TEM) is square with a = 1192pm, no-commensurate with that of graphite.

International audience; We present the successful intercalation of europium into graphite by using an original method based on LiCl-KCl molten salts mixture. After solubilization of europium in the liquid chlorides mixture at 450 °C, reactivity toward graphite is investigated. We evidence the formation of the first stage EuC$_6$ Graphite Intercalation Compound (GIC) with a repeat distance Ic = 487 pm. Using 00$l$ X-ray diffraction and ion beam analysis, we show that europium is intercalated into the bulk with remarkable degree of homogeneity. This is also confirmed by magnetic measurements that clearly put in evidence the antiferromagnetic transition at about T$_N$ = 40 K. Below such temperature the characteristic step-like behavior of metamagnetic transitions was found by isothermal magnetization measurements, that is generally visible only in highly pure samples.

Elimination of the negative component of the unipolar atrial electrogram is a reliable indicator of the creation of a transmural lesion. Contact-force (CF) sensing technology has the potential to increase the durability of pulmonary vein isolation (PVI). In the present multicenter study, we assessed the 2-year sinus rhythm (SR) maintenance rate in patients with paroxysmal atrial fibrillation (PAF) after PVI guided by these two approaches. Two hundred fifteen consecutive PAF patients (62.1 ± 10.1 years, 65 women) were prospectively enrolled. All patients underwent PVI under CARTO guidance according to a systematic contiguous “point-by-point” approach, using radiofrequency energy, and a CF externally irrigated ablation catheter with the goal of at least 10g (ideally 20g) of force. The ablation endpoint of each individual lesion was elimination of the negative component of the unipolar atrial signal. The procedural endpoint was PVI with bidirectional block. All PVs were successfully isolated. After 30 min of waiting time, 35 patients (16%) had PV reconnection and in all of them, the PVs were re-isolated. Two years after a single ablation procedure, 187 patients (87%) remained arrhythmia free, without anti-arrhythmic drugs. Of the 28 patients presenting with AF recurrence, 25 had PV reconnection and underwent repeat PVI while in the remaining 3 patients, all four PVs were isolated and extra-PV triggers were identified. There were six groin hematomas and one transient ischemic attack. Unipolar atrial signal analysis combined with CF sensing ensures a robust 2-year SR maintenance rate in the treatment of PAF. Clinical trial registration—URL: http://www.clinicaltrials.gov . Unique identifier: NCT02520960.

Norodom Anne-Thida, Lagrange Philippe, Lemoine Aline. Travaux de la commission du droit international (soixante-huitième session) et de la sixième commission (soixante et onzième session). In: Annuaire français de droit international, volume 62, 2016. pp. 265-302.

Background: This study aimed to describe the influence on dual-chamber devices' expected longevity of devices' settings. Methods: Data from patients implanted with dual chamber devices (Symphony™, SORIN CRM SAS, Clamart, France) from 2003 to 2006 were collected in registries. Programmer files were retrieved: device-estimated longevity, assessed through algorithm prediction, was analyzed according to device settings. Results: One thousand sixty-eight recipients of dual chamber pacemaker in sinus rhythm (75.3 ± 11.1 years, 54.5% male, ventricular block 30%, brady-tachy syndrome 21%, and sinus node dysfunction 49%) were followed up to 14.2 ± 12.1 months (ranging from first quartile Q1: 2.9 months to fourth quartile Q4: 49.3 months) after implantation. DDD with automatic mode conversion and minimized ventricular pacing (SafeR) modes were programmed in 34.3%, 2.9%, and 62.8% of the patients, respectively. The mean total longevity estimated by the device was 134.1 ± 31.5 months (11.2 ± 2.6 years). Significant increase in longevity was observed in devices undergoing at least one reprogramming (134.4 ± 31.4 months) versus device presenting no reprogramming (103.4 ± 32.3 months, P = 0.0005). The parameters associated with the major increase in mean longevity were the mode (mean longevity increase of +23.9 months in SafeR as compared to DDD mode, P < 0.0001) and the atrial (A) and ventricular (V) amplitudes (mean longevity increase of +29.6 and +26.9 months for a decrease of less than 1V in A and V outputs respectively, P < 0.0001). Conclusion: This study provides information on dual chamber pacemakers’ longevity and highlights the impact of devices’ reprogramming on expected longevities. PACE 2012; 35:403–408)

Norodom Anne-Thida, Lagrange Philippe. Travaux de la commission du droit international et de la Sixième commission. In: Annuaire français de droit international, volume 61, 2015. pp. 331-374.

A first stage binary graphite intercalation compound was synthesised in the lithium–europium–graphite system by direct immersion of a pyrolytic graphite platelet in a molten lithium-based alloy with a well chosen Li/Eu ratio at 350 °C. The as-obtained bulk EuC 6 compound exhibits mono-layered intercalated sheets of europium surrounded by two graphene sheets with a repeat distance equal to 487 pm. The three dimensional study of the EuC 6 crystal structure shows a hexagonal symmetry for this compound that crystallises in a P 6 3 / mmc space group with the following unit cell parameters: a = 430 pm and c = 974 pm.

In the lithium–europium–graphite system, a novel ternary compound was synthesised by direct immersion of a pyrolytic graphite platelet in a molten lithium-based alloy with a well chosen Li/Eu ratio at 400 °C. The ternary compound exhibits poly-layered intercalated sheets mainly constituted of two europium planes. Its chemical formula can be written LixEuC4, since the amount of lithium is still not determined. The 151Eu Mossbauer spectra clearly indicate a +II valence for europium. The magnetic susceptibility and the magnetisation versus temperature reveal a complex behaviour which is qualitatively described thanks to structural hypothesis and analogies with the magnetic properties of the binary EuC6 compound. A first ferromagnetic transition occurring at 225 K is attributed to interactions between both intercalated europium planes. The lower temperature susceptibility behaviour can be interpreted by antiferromagnetic interactions between in-plane neighbours and ferromagnetic interactions along the c-axis.

Lithium intercalates easily into graphite either by chemical way or by electrochemical way. This well-known reaction leads to the first stage LiC 6 binary compound. However, it is more difficult to prepare a ternary compound by intercalation of a lithium alloy. This is mainly due to thermodynamical causes. Nevertheless, it has been observed that a few well-chosen alloys (Ca–Li and Eu–Li) are able to intercalate into graphite. Calcium and europium have been used for well defined reasons. Although in these alloys both metals present are able to intercalate by themselves, the intercalated sheets are poly-layered. This observation is entirely original, but it can be easily explained. On the other hand, it has been established that, using well-chosen lithium alloys, calcium and europium can also intercalate alone into graphite, leading to the corresponding binary phases. In these occasions, lithium appears essentially as a factor able to promote the melting of the second metal and its intercalation by a preliminary spreading of the graphene planes.

A liquid–solid synthesis method to prepare high quality bulk samples of MC6 binary graphite intercalation compounds (with M = Ca, Ba and Eu) is described. Liquid Li–M alloys are used to synthesize such compounds for two reasons: first, lithium spreads apart the graphene sheets and second, it allows the intercalation reactions to be carried out at temperatures sufficiently low to avoid the formation of carbides. The intercalation reactions were investigated precisely, that reveal the existence of a two-steps mechanisms. Several attempts performed in order to synthesise SrC6 failed. However, all the possible conditions were not tried, so that the synthesis of pure SrC6 using this liquid–solid synthesis route is still unsolved.

International audience; The action on graphite of liquid arsenic-potassium alloys leads to the formation of a new series of graphite intercalation compounds. Two ternary phases of first stage have been observed and isolated. The alpha-type phase is obtained by action on graphite of composition alloys close to that of defined K3As compound. On the other hand, the beta-phase is easily obtained by action on graphite of K-As alloys whose chemical stoichiometry is equal or near to the 37 at.% As eutectic point composition. The Fourier transform analysis of the 001 reflexions family of these two phases showed that the intercalated metallic sheets between graphitic gaps in these phases are generally three-layered stacking according to K/As/K sequence along c-axis. An exam, by means classical X-ray diffraction and transmission electronic microscope (TEM) of the in-plane structure of these compounds revealed that the intercalated metallic sheets are perfectly crystallised and an equatorial stratum was defined for each of them. Electrical conductivity measurements have been carried out on these phases along both axis of graphite and showed that they are strongly anisotropic and exhibit a metallic character in parallel to graphitic plans.

International audience; The graphene plane possesses a high hexagonal symmetry. Currently, it is largely studied as 2D crystal, especially due to its very interesting potential electronic properties. It is also frequently studied in the 3D stackings as graphite. When a layer of a chemical species is dropped off on a graphene layer, it is common to observe a right adaptation between both 2D crystal networks. This commensurability is consistently studied in this paper by means of a mathematical approach. Through this method, it has been possible to take an inventory of all 2D unit cells commensurate with hexagonal graphene cell. Hexagonal, rectangular and oblique cells can be perfectly listed for the different values of the number of carbon atoms included in the cell. Numerous experimental examples are given in the field of graphite intercalation compounds. And very especially the graphite-electron donors lamellar compounds have been used in order to illustrate the method and its results.

Potassium–thallium, potassium–mercury, and potassium–gold alloys can be intercalated into graphite, leading to the formation of poly-layered ternary compounds. Different ways of synthesis are involved for the preparation of the corresponding Graphite Intercalation Compounds (GICs). The as-prepared bulk GICs are described in a comparative study, regarding their chemical formula, their formation mechanism, and their structural and superconducting properties. Analogies and differences are pointed out. [TANSO 2015 (No. 268), 145–53.]

The electronic structure of the ternary intercalated graphite beta-KS(0.25)C3 is studied by means of a first-principles density functional theory approach. The nature of the partially filled bands is analyzed, and the K sublayers of the intercalate are shown to have an important contribution to the Fermi surface. This K-based contribution confers a sizable three-dimensional character to the conductivity even if considerably less than that for the related binary KC8. The electronic structure of beta-KS(0.25)C3 differs noticeably from that of the related ternary compound, KH(x)C4. The charge transfer is analyzed, and a way to evaluate it, which can be used in general for intercalated graphites, is proposed. The charge transfer per C atom in this ternary material is shown to be smaller than that in the KC8 binary compound despite a more favorable stoichiometry ratio between K and C.

It is possible to synthesise easily the first stage LiC 6 compound by immersing a pyrographite platelet in liquid lithium. The same experiments carried out using liquid lithium–calcium alloys with a Li/Ca atomic ratio, respectively, of 1 and 2, at 350 °C for ten days give two first stage ternary graphite intercalation compounds containing five- and seven-layered intercalated sheets, respectively. The experiments carried out with a liquid alloy rich in lithium (Li/Ca atomic ratio of 3) at 350 °C for ten days, in order to be sure that the thermodynamical equilibrium is reached, show that the reaction product is the CaC 6 binary compound, and not LiC 6 . This very unexpected result can be partially explained by kinetical and thermodynamical argumentation. Before the equilibrium, the experiments show that lithium intercalates first, leading to a mixture of several stages of graphite–lithium compounds with an increasing enrichment in LiC 6 . This compound disappears gradually to the benefit of CaC 6 , which remains alone in the system. In these conditions, it appears that CaC 6 is more stable than LiC 6 . This particular situation in these systems is observed for the first time. The temperature has a strong influence on the reaction. The ternary compounds are mainly obtained at the lowest temperatures whereas the binary ones are obtained for higher values.

In this letter, we report the discovery of superconductivity in Li3Ca2C6. Several graphite intercalation compounds (GICs) with electron donors, are well known as superconductors. It is probably not astonishing, since it is generally admitted that low dimensionality promotes high superconducting transition temperatures. Superconductivity is lacking in pristine graphite, but after charging the graphene planes by intercalation, its electronic properties change considerably and superconducting behaviour can appear. Li3Ca2C6 is a ternary GIC, for which the intercalated sheets are very thick and poly-layered (five lithium layers and two calcium ones). It contains a great amount of metal (five metallic atoms for six carbon ones). Its critical temperature of 11.15 K is very close to that of CaC6 GIC (11.5 K). Both CaC6 and Li3Ca2C6 GICs possess currently the highest transition temperatures among all the GICs., 5 pages, 3 figures

A novel and efficient synthesis method concerning the preparation of the first stage calcium graphite intercalation compound is provided. It makes use of a reaction between liquid metallic alloy and pyrolytic graphite. From now on it is especially easy to obtain bulk CaC6 samples. Thanks to such samples, it was possible to study in detail the crystal structure of this binary intercalation compound. It has been entirely specified, so that we know that CaC6 crystal is rhombohedral and belongs to the R 3 ¯ m space group with the following parameters: a = 517 pm and α = 49.55 ° . The elemental unit cell contains one calcium atom and six carbon atoms. In this paper, we show also how the various MC6 structures evolve according to the size of the intercalated element and to the bond nature that appears in the final compound. CaC6 is unique, since all the other MC6 compounds exhibit a hexagonal symmetry.

Intercalation of lithium into graphite is of great interest, due to its largely expanded use as negative electrode material in the Li-ion batteries, especially the LiC6 compound. Recently, the first ternary intercalation compounds associating lithium with a second metallic element were synthesized by immersing pyrographite platelet in a molten Ca–Li alloy. Photonic and neutronic diffractions on these graphite–lithium–calcium compounds reveal that lithium and calcium layers are intercalated between graphene sheets. However, the precise elemental composition still lacks. Chemical analysis gives an average composition but carbon is not measured in the same sample as calcium and lithium. Electron microprobe, SEM and TEM do not allow to determine lithium concentration and its distribution in these compounds. This paper reports the first elemental characterization of carbon–calcium–lithium intercalation compounds by means of nuclear microprobe. Using a 3.1 MeV proton beam, both lithium, calcium and carbon can be determined within a single measurement, from the 7Li(p,α)4He nuclear reaction and from elastic scattering for calcium and carbon respectively. In the graphite–lithium–calcium system, three different intercalation compounds were synthesized, containing low to high lithium content. The mapping of the samples reveals lateral and also mainly in depth heterogeneity (along the c axis).

Three new layered compounds were synthesised by immersing a pyrographite platelet in a molten Ca−Li alloy creating a new graphite intercalation compound family. The samples were studied by X-ray and neutron diffraction, revealing that the intercalated sheets are polylayered. The study of the 00l reflections allowed us to establish the c-axis stacking of these three phases. The α-phase exhibits a five-layered intercalated sheet which has something in common with a Li−Ca−Li−Ca−Li slice cut in the CaLi2 structure (ThMn2 Laves phase type). The β-phase, which is richer in metallic elements and with a greater repeat distance, possesses seven-layered intercalated sheets due to the splitting of the middle lithium plane in three. The third phase is a pseudo-binary compound, containing monolayered sheets and with a formula close to CaC6. Electron microdiffraction allowed us to determine the 2D unit cell for each compound, all of which were commensurate with that of graphite. Charge transfer from the intercalate to the host lattice was evaluated for the three phases from hk0 data, leading to high values. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Lithium can intercalate easily into graphite leading to the LiC 6 compound but the synthesis of a ternary compound associating lithium with a second element seems to be difficult. Recently, graphite–lithium–calcium compounds were obtained by reaction of a pyrographite platelet in a molten Ca–Li alloy at 350 °C. Chemical analyses, electron microprobe, SEM and TEM give the C/Ca ratio but do not allow to determine the lithium concentration and its distribution in these compounds. Therefore, the nuclear microprobe was used to characterise more precisely these ternary intercalation compounds. Using a 3.1 MeV proton beam, the three elements can be quantified simultaneously from the 7 Li(p,α) 4 He nuclear reaction for lithium and from elastic scattering for calcium and carbon. Among the three synthesised compounds, one of them (α phase) opposes great heterogeneities in lithium and the amount of lithium in the β phase is very high (C/Li ratio approaches 2).

Ternary graphite intercalation compounds associating an alkali metal and an electronegative element are described. The synthesis is more often realized in molten alkali metal media containing the associate electronegative element or radical in the adequate concentration. The intercalated sheets are systematically polylayered. The arrangement along c-axis and the in-plane structures are described. The physical properties of the compounds are precised.

After a short overview on the co-intercalation into graphite of light alkali metals––lithium and sodium––with a third element, novel results concerning the co-intercalation of these alkali metals with an alkaline earth metal are given. The intercalation into graphite of lithium together with magnesium, calcium, strontium and barium is investigated, and the reaction products are described and characterised by X-ray diffraction. Ternary intercalation compounds were synthesised only in the graphite–lithium–calcium system. In the other systems, binary compounds were obtained. The co-intercalation of sodium and the alkaline earth metals calcium, strontium and barium is studied too. No ternary compounds were obtained. However, in the case of the sodium–barium system, a discussion on ternary graphite–sodium–barium compounds previously published is opened. Several data are in favour of a graphite–sodium–oxygen compound instead of a graphite–sodium–barium one.