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Conventional high-chromium ferritic / martensitic steels, such as T91 and AISI 316 L as well as the new oxide dispersed strengthened (ODS) steels, i.e. Fe-Cr (ferritic or martensitic) with a fine Y2O3 dispersion, are promising candidates as structural materials for applications in aggressive environments. In order to improve the efficiency and lifetime of structural materials for liquid metal fast reactor (LMFR), where liquid lead (Pb) is used as coolant, the investigations are currently focused on the interfacial phenomena occurring at the liquid Pb/steel interfaces. The better understanding of the interfacial phenomena is the key issue for the selection of structural materials meeting the requirements of the demanding application. In the present work, a fundamental study on the wetting characteristics and the interfacial phenomena of liquid Pb in contact with T91, AISI 316L, ODS- 12Cr and ODS-14Cr steels over the temperature range 550�820�C and under different oxygen containing atmospheres is reported.

Aims The aim of this study is to report heart failure hospitalization (HFH) rates and associated costs within 12 months following implantable cardioverter defibrillator (ICD)/cardiac resynchronization therapy defibrillator (CRT‐D) device replacement or upgrade from ICD to CRT‐D. Methods and results The DEtect long‐term COmplications after icD rEplacement (DECODE) was a prospective, single‐arm, multicentre cohort study that explored complications in ICD/CRT‐D recipients. All clinical and survival data at 12 months were prospectively analysed. For each adjudicated HFH, admission and discharge dates and ICD‐9‐CM diagnosis and procedure codes were recorded. The reimbursement for each HFH was calculated for each diagnosis‐related group code. Between 2013 and 2015, 983 patients (mean age 71 years, male 76%, mean left ventricular ejection fraction 35%, and New York Heart Association Class I/II 75.6%) were enrolled. Patients underwent device replacement (900; 91.6%, 446 ICD/454 CRT‐D) or ICD upgrade to CRT‐D (83; 8.4%). Post‐replacement hospitalizations occurred in 220 patients, with the primary discharge diagnosis identifying cardiovascular causes in 175 patients (80%). Fifty‐five (5.6%) patients experienced at least one HFH. Overall, 91 HFH events occurred (9.6% event rate, 95% confidence interval: 7.7–11.7) in 70 patients; 66 (6.7%) patients died, 40 (60.6%) of cardiovascular causes. The HFH rate was significantly higher following upgrades, and the occurrence of HFH was associated with an 11‐fold increased mortality risk (95% confidence interval: 5.9–20.5, P

The COVID-19 pandemic caused by SARS-CoV-2 has greatly modified outpatient follow-ups. The aim of this retrospective study was to evaluate the organizational modalities and clinical effects of rearrangements of pacemaker (PM) and implantable cardioverter-defibrillator (ICD) outpatient visits performed in our centers at Ravenna and Lugo Hospitals, Italy, during the pandemic outbreak in 2020.All scheduled in-person device follow-up visits in March-December 2020 have been considered. On the basis of documented past functioning of each device and of remote monitoring (RM) capabilities, in-person visits were either performed or postponed at variable times. The characteristics of the follow-ups and the device-related clinically relevant events were analyzed, the latter being further divided into serious malfunction and problems to be corrected by device reprogramming.Overall, 27% of in-person visits were postponed (n = 576) (36% of ICDs and 25% of PMs), peaking 62% in March-May 2020. RM compensated nearly all hold-ups in ICDs and just 63% of postponements in PMs. The postponement-caused delay between in-person visits was 5.6 ± 1.1 months for ICDs and 4.7 ± 1.2 months for PMs; in 24% of ICDs the time interval between in-person visits was ≥18 months. Clinically relevant events were 56 (18 [4.4%] in ICDs, 38 [2.1%] in PMs), with no deaths and 21 serious malfunctions (4 [1%] in ICDs, 15 [0.8%] in PMs). RM identified all ICD malfunctions, while it was not available in the affected PMs. In comparison with the year 2019, serious malfunctions increased, though the difference was not significant. Monthly RM transmissions increased by 2.3 fold.In our single-center experience during the COVID-19 pandemic, numerous in-person PM/ICD follow-up visits were postponed, and delays were well beyond the previously recommended time limits. However, device-related malfunctions did not increase, notably, when RM capabilities were used.

Friedreich ataxia is the most common form of hereditary ataxia. Heart involvement in Friedreich ataxia is common and can include increased left ventricular wall thickness, atrial fibrillation, and in the later stages, a reduction of left ventricular ejection fraction. We present the case of a 45-year-old man with a history of paroxysmal atrial fibrillation and a congestive heart failure, hypertension, age ⩾ 75 years, diabetes mellitus, stroke, vascular disease, age 65–74 years, and female sex (CHA2DS2-VASc) score of only 1 (because of reduced left ventricular ejection fraction) who presented with pneumonia and was also found to have atrial fibrillation with a rapid ventricular response. Despite already being on long-term therapy with a non-vitamin K-antagonist oral anticoagulant, a transesophageal echocardiogram showed a mobile floating thrombus in the left atrial appendage. In accordance with previous necropsy evidence of thrombosis and thromboembolism in Friedreich ataxia subjects who likely have had only non-sex-related CHA2DS2-VASc score ⩽1, this case suggests that the risk of thromboembolism in Friedreich ataxia subjects with atrial fibrillation may not be adequately predicted by the sole CHA2DS2-VASc score.

Funding Acknowledgements Type of funding sources: None. Background Percutaneous endocardial left atrial appendage (LAA) occlusion (LAAO) in non-valvular atrial fibrillation (AF) seems comparable to anticoagulation therapy (OAC) as regards thromboembolic risk reduction with a possible additional decrease in major bleeding. LAAO is currently limited to patients with contraindications to OAC, due to its high costs and procedural risks, but better pre-procedural planning and operative techniques might improve the outcome widening practical indications. Computational fluid dynamics (CFD) represents a valuable non-invasive approach to estimate physiologically significant hemodynamic parameters in a complex fluid dynamics system. It might provide a helpful in silico simulation of blood flow patterns within the LA and LAA by using 3D patient-specific models, allowing LAAO planning and effects prediction. Purpose This study’s aim was to simulate the fluid dynamics effects of LAAO in AF patients to predict patient-specific hemodynamic changes caused by applying the two most popular devices. Methods LAAO was simulated on the 3D LA anatomical models obtained from CT data in 5 AF patients, considering the device specific shape. CFD simulations in AF condition were performed both on the whole LA model and on the models with the LAAO performed with the two devices. Significant fluid dynamics indices (blood velocity, vortex structures, LAA ostium velocity, LA blood stasis) were computed to evaluate the changes in the flow patterns after LAAO in relation to the thrombogenic risk. Results Overall we found a more effective washout within the LA after LAAO, in terms of a different spatial distribution of velocities (see figure for a qualitative evaluation of LA blood flow velocity in one patient: (A) model with LA and LAA; models after LAAO applying the Amulet (B) and the Watchman (C) device) and vortex structures (after LAAO, they were decreased in number and increased in size). Moreover, a higher velocity at the mitral valve and at the LAA ostium (peak velocity: 12-17 cm/s in the models with LAA, 40-60 cm/s in LAAO_A and 35-65 in LAAO_W) was detected together with a slightly improved washout effect in terms of blood stasis with the Watchman device (stasis: 3.1-5.7% in the models with LAA, 1.9-4.1% in LAAO_A, 1.7-3.7% in LAAO_W). Conclusions A workflow for simulating the fluid dynamics effects of endocardial LAAO in AF was developed and tested. CFD provides a valuable tool to quantify hemodynamic changes after LAAO and assess thrombogenic risk in patient-specific LA and LAA. Our preliminary results suggest that endocardial LAAO favourably affects blood fluid dynamics in the LA. Abstract figure

Purpose: Generator impedance (Im) mapping with constant contact force (CF) by tip catheter at PV isolation (PVI) was assessed for a proposal of tissue characterization at PV-LA junction (PV-LAJ). Methods: In this observational, prospective, single-center study, Im mapping at constant CF = 10g (± 2g) was performed before PVI at PV-LAJ. PV in-vein, PV ostium (PVos), and antrum (PVan) contours were manually traced based on the 3D electroanatomic map (3DEAM) integrating intracardiac echocardiography and computerized tomography. PVan contour-methods based on Im mapping was defined on 3DEAM as the atrial-like Im contour closest to PVos, and its distance from anatomical PVan contour > 5mm was assumed as the non-concordance marker between contour and methods. Results: Sixty-two patients (62 ± 9years; 43 males) were enrolled, and 244 PV-LAJ were assessed. From in-vein PV to LA and, less prominently, from PVos to PVan and LA, Im showed a unidirectional decrease with highly variable individual-specific distribution and values. PVan non-concordance was found in 59/665 segments (8.8%), 18% of PV-LAJs, and 53% of pts; it prevailed in superior PV-LAJ and measured on average 7.2 ± 1.1mm. Im decrease patterns and non-concordance were not associated with any clinical or anatomical feature, including PV dimensions and shape. Conclusions: Im mapping of LA-PVJ at constant CF added to 3DEAM may consistently track the tissue transition from PV to LA. PVan identified by Im was often located more toward LA than the 3D anatomical PVan, particularly in LSPV, suggesting the potential advantage of avoiding ablation of venous-like tissue. Im mapping can deserve further investigation for target characterization at LA-PVJ.

The present study aims to deepen the knowledge on the corrosion behavior of martensitic T91 steel in contact with liquid lead in view of its application in advanced nuclear energy systems. Steel samples have been analyzed after the immersion in stagnant molten lead at different temperatures (550°C to 650°C) and for an exposure time of 550 h. In order to evaluate the influence of different oxidizing conditions, the corrosion tests were performed under both Ar and Ar-H2 mixtures. Within the temperature range applied, the oxygen content in the liquid lead was Co = 6.8±2.7 × 10−2 wt% and Co = 9.2±3.6 × 10−8 wt%, respectively. When the Ar atmosphere was applied, dissolution of iron and chromium has been observed for temperature above 590°C. Conversely, under an Ar-H2 mixture atmosphere, mainly the presence of internal oxidation along the grain boundaries whose depth increases with temperature was detected.

Background An automated method for 3D reconstruction of coronary sinus (CS) lead’s pacing cathode trajectory (3DTJ) was proposed to acutely predict long term left ventricular (LV) mechanic response to cardiac resynchronization therapy (CRT). Preliminary data showed that 3DTJ at biventricular pacing (BIV) start changed in CRT responders (R) to be, becoming less eccentric and more multi-directional, as described by the ratio between its two major axes (S1/S2). Purpose The TRAJECTORIES study (Trajectory Changes Of Coronary Sinus Lead Tip And Cardiac Resynchronization Therapy Outcome, NCT02340546) is an observational study by seven Italian centers about the prediction of CRT-induced LV reverse remodeling by means of the acute 3DTJ changes at CRT implant. Methods In CRT implants with standard indications, stable CHF and regular ventricular rhythm, a fluoroscopic sequence in two standard X-rays views of a few seconds was acquired immediately before (T-1) and after the start of BIV (T0). 3DTJ of CS lead cathode pole throughout the cardiac cycle at T-1 and T0 were reconstructed and analyzed. Changes of the ratio between its two major axes (S1/S2) between T-1 and T0 (ΔS1/S2), were compared with the volumetric response at six-month f.u: the percent negative variation of S1/S2 (ΔS1/S2 Results Out of 119 patients enrolled in 42 months, 74 pts ended f.u. (55 m; age 69 ± 10) and 30 dropped–out. Patients baseline features were: ischemic heart disease (IHD) 34 /74 pts; sinus rhythm 64/74 pts; upgrade from PM/ICD 13/74 pts; QRS morphology with LBBB 57/74, intraventricular aspecific delay 6 and RV pace 11 pts; LV ejection fraction (EF) 30 ± 9%; QRS duration 162 ± 25 ms. At f.u., volumetric R were 45/74 (60%). Concordance between ΔS1/S2 (as either ΔS1/S2 0) and volumetric response was 77% overall (57/74), 82% in R (37/45), 69% in non-R (20/29). Non-concordant patients were mostly non-R: 52% vs 35% of non-R in concordant group, but no other differences were found. The proposed 3DTJ metric showed sensitivity = 72%, specificity =80%; positive predictive value = 69%, negative predictive value = 82%. Conclusions Metrics of 3DTJ can be useful to acutely predict CS pacing site-specific response to CRT in long-term, above all in R. 3DTJ assessment might highlight aspects of CRT effects on LV mechanics.

Atrial fibrillation (AF) is responsible for 15–18 % of all strokes. In AF patients, the left atrial appendage (LAA) represents the main thrombogenic spot, being the site of 90% of intracardiac thrombus formation. Therefore, the occlusion of the LAA (LAAO) is a novel strategy for cardioembolic stroke prophylaxis. The aim of this study was the simulation of the fluid dynamics effects of the LAAO in AF patients, by applying two different devices (Amulet™ and Watchman™), in order to predict patient-specific hemodynamic changes due to LAAO and to detect the most effective devices in reducing stroke risk as well.

Undoped as well as K-doped (40%), Y-doped (40%), Zr-doped (10%), and Mo-doped (12.5%) strontium barium niobate Sr0.5Ba0.5Nb2O6 (SBN50) materials have been investigated to explore the effect of heavy doping on the structural and functional properties (thermo-power, thermal and electrical conductivities) both in the as prepared (oxidized) and reduced states. For all materials, the EXAFS spectra at the Nb – K edge can be consistently analyzed with the same model of six shells around the Nb sites. Doping mostly gives a simple size effect on the structural parameters, but doping on the Nb sites weakens the Nb–O bond regardless of dopant size and charge. Shell sizes and Debye–Waller factors are almost unaffected by temperature and oxidation state, and the disorder is of static nature. The functional effects of heavy doping do not agree with a simple model of hole or electron injection by aliovalent substitutions on a large band gap semiconductor. With respect to the undoped samples, doping with Mo depresses the thermal conductivity by ~ 30%, Y doping enhances the electrical conductivity by an order of magnitude, while Zr doping increases the Seebeck coefficient by a factor of 2–3. Globally, the ZT efficiency factor of the K-, Y-, and Zr-doped samples is enhanced at least by one order of magnitude with respect to the undoped or Mo-doped materials., This work has been supported by the “Materiali Avanzati” Program (Projet code 2012-0815) of the Cariplo foundation (Milano, Italy). BM08 (LISA)@ESRF is acknowledged for the provision of beam-time, travel and accommodation expenses (Exp. HC-1582).

Background Ablation technique targeting high-amplitude signals (maximum voltage guided - MVG -) on the cavotricuspid isthmus (CTI) has emerged as viable alternative option compared to standard anatomical approach (ST) for the creation of bidirectional conduction block (BDB) across the isthmus but limited data are available to date. Purpose To evaluate the effectiveness of acute and long-term outcome of CTI ablation through MVG technique for AFL compared to standard linear (SL) lesion ablation. Methods Atrial Flutter Ablation in a Real World Population (LEONARDO) is a prospective, multicenter cohort study aimed at providing an estimate of acute to long-term outcome in a large population of patients (pts) indicated for AFL ablation. Recurrence of AFL were retrieved at 12-month follow-up. Complete BDB was defined by agreement with the presence of widely split double potentials (DP) along the ablation line and assessment of the atrial activation sequence (AAS). For MVG technique the ablation catheter was positioned at the site of maximum local electrogram voltage. Results Two-hundred fifteen consecutive pts were included (mean age 68 years, 73% male). A median of 4 [2–6] ablation lesions were required. Median follow up was 359 [192–443] days. Complete BDB was achieved in 175 (81.4%) pts (9 pts had DP only criterion, 30 pts had AAS only criterion whereas in 1 pt we failed to reach a BDB). In the 106 pts with complete data at 1-year follow-up, 10 (9.4%) had a recurrence of AFL. 171 pts (79%) underwent a SL ablation whereas 44 pts (21%) were treated by MVG approach. The median number of lesions/pt was significantly lower in the group of pts targeted with MVG compared to the SL approach (3 [2–4] vs 4 [2–8], p Conclusion Ablation of a targeted site through MGV approach seems to be safe and effective as standard anatomical ablation technique. This strategy may avoid unnecessary ablation of the entire anatomic isthmus. Acknowledgement/Funding None

Atrial fibrillation is associated with a five-fold increase of the stroke risk. Left atrial appendage (LAA) is the atrial site with the highest blood stasis risk, increasing thrombus formation and stroke. Recent studies have been focused on the association between the left atrial appendage anatomical features and the stroke risk. However, conflicting results have been published. In this context, clinical studies suggested the stroke risk stratification could be improved by using haemodynamics information on the left atrium and mainly on the left atrial appendage. Therefore, the aim of this study was the design and development of a method which enabled to reconstruct and generate several LA anatomical models, where each one was characterized by a different LAA morphology. These anatomical models represent the computational domain for the computational fluid dynamics simulations of the haemodynamics within the left atrium and LAA.

The zircon polymorph of GdCrO4 has a large magnetocaloric effect over a wide temperature range, with |ΔST| > 20 J/kg·K from 6 K to 34 K, for a magnetic field of 9 T. This unusual behaviour is very interesting on magnetic refrigeration applications, for liquefying H2 or natural gas. The mean-field approach explains that it is due to the weaker Gd-Cr magnetic exchange relative to the Cr-Cr one, while the Gd-Gd exchange is negligible. This possibility has not been sufficiently studied and opens an interesting strategy to design more efficient materials for magnetic refrigeration.

BACKGROUND: The rate of device replacement in pacemaker recipients has not been investigated in detail. HYPOTHESIS: Current pacemakers with automatic management of atrial and ventricular pacing output provide sufficient longevity to minimize replacement rate. METHODS: We considered a cohort of 542 pacemaker patients (age 78 ± 9 years, 60% male, 71% de‐novo implants) and combined 1‐month projected device longevity with survival data and late complication rate in a 3‐state Markov model tested in several Monte Carlo computer simulations. Predetermined subgroups were: age < or ≥ 70; gender; primary indication to cardiac pacing. RESULTS: At the 1‐month follow‐up the reported projected device longevity was 153 ± 45 months. With these values the proportion of patients expected to undergo a device replacement due to battery depletion was higher in patients aged

The syntheses, structures, and magnetic properties of two heterometallic CuII-LnIII (LnIII = Gd, Tb, and Dy) families, utilizing triethanolamine and carboxylate ligands, are reported. The first structural motif displays a nonanuclear {CuII 2LnIII 7} metallic core, while the second reveals a hexadecanuclear {CuII 4LnIII 12} core. The differing nuclearities of the two families stem from the choice of carboxylic acid used in the synthesis. Magnetic studies show that the most impressive features are displayed by the {CuII 2GdIII 7} and {CuII 4GdIII 12} complexes, which display a large magnetocaloric effect, with entropy changes -ΔSm = 34.6 and 33.0 J kg-1 K-1 at T = 2.7 and 2.9 K, respectively, for a 9 T applied field change. It is also found that the {CuII 4DyIII 12} complex displays single-molecule magnet behavior, with an anisotropy barrier to magnetization reversal of 10.1 K., K.S.M. thanks the Australian Research Council (ARC) and the Australia-India Strategic Research Fund (AISRF) for support of this work. M.E. acknowledges financial support from MINECO through grant MAT2012-38318-C03-01.

BACKGROUND: Consensus guidelines define indications for cardiac resynchronization therapy (CRT), but the variability in implant rates in 'real world' clinical practice, as well as the relationship with the epidemiology of heart failure are not defined. METHODS AND RESULTS: In Emilia-Romagna, an Italian region with around 4.4 million inhabitants, a registry was instituted to collect data on implanted devices for CRT, with (CRT-D) or without defibrillation (CRT-P) capabilities. Data from all consecutive patients resident in this region who underwent a first implant of a CRT device in years 2006-2010 were collected and standardized (considering each of the nine provinces of the region). The number of CRT implants increased progressively, with a 71% increase in 2010 compared to 2006. Between 84 and 90% of implants were with CRT-D devices. The variability in standardized implant rates among the provinces was substantial and the ratio between the provinces with the highest and the lowest implant rates was always greater than 2. Considering prevalent cases of heart failure in the period 2006-2010, the proportion of patients implanted with CRT per year ranged between 0.23 and 0.30%. CONCLUSIONS: The application in 'real world' clinical practice of CRT in heart failure is quite heterogeneous, with substantial variability even among areas belonging to the same region, with the need to make the access to this treatment more equitable. Despite the increased use of CRT, its overall rate of adoption is low, if a population of prevalent heart failure patients is selected on the basis of administrative data on hospitalizations.

Magnetite nanoparticles coated with silica, obtained by a sol-gel process in the reverse micelle microemulsion, were characterized and homogeneously suspended in water in order to assay their biocompatibility toward blood cells, in view of a potential medical use of this material. Their hemolytic, pro-thrombotic and pro-inflammatory properties were observed.

The ferromagnetic zircon-type phase of GdCrO4 presents high values for the magnetocaloric (MC) parameters. This compound has large isothermal entropy changes ΔST under the magnetic field action in a wide temperature range, from 5 to 35 K, reaching a maximum |ΔST|=29.0±0.1J/kgK at 22 K, for a field increment ΔB=9 T. It orders ferromagnetically at TC=21.3K via the Cr-Cr exchange interaction and shows a second transition at 4.8 K due to the ordering of the Gd sublattice. The large MC effect is enhanced by the polarization of the Gd3+ ions by the Cr5+ ones via a weaker Gd-Cr interaction. This effect is an interesting feature to be considered in the search for new compounds with a high MC effect in the range of liquid hydrogen or natural gas, regarding the liquefaction of gases by magnetization-demagnetization cycles. This paper contains experimental measurements of magnetization, heat capacity, and direct determinations of the MC effect. The magnetic contribution to the heat capacity Cm has been obtained after subtracting the lattice component. Approximate values for the exchange constants J1 (Cr-Cr) and J3 (Gd-Cr) have been deduced from Cm., This work has been funded by the Spanish MINECO through Projects No. MAT2013-44063-R and No. MAT2013-44964-R, DGA Consolidated Group E100, and Comunidad de Madrid Project No. S2009/PPQ-1626.

Aims We investigated the applicability of the Ventricular Capture Control (VCC) and Atrial Capture Control (ACC) algorithms for automatic management of cardiac stimulation featured by Biotronik pacemakers in a broad, unselected population of pacemaker recipients. Methods and results Ventricular Capture Control and Atrial Capture Control were programmed to work at a maximum adapted output voltage as 4.8 V in consecutive recipients of Biotronik pacemakers. Ambulatory threshold measurements were made 1 and 12 months after pacemaker implant/replacement in all possible pacing/sensing configurations, and were compared with manual measurements. Among 542 patients aged 80 (73–85) years, 382 had a pacemaker implant and 160 a pacemaker replacement. Ventricular Capture Control could work at long term in 97% of patients irrespectively of pacing indication, lead type, and lead service life, performance being superior with discordant pacing/sensing configurations. Atrial Capture Control could work in 93% of patients at 4.8 V maximum adapted voltage and at any pulse width, regardless of pacing indication, lead type, and service life. At 12-month follow-up, a ventricular threshold increase ≥1.5 V had occurred in 4.4% of patients uneventfully owing to VCC functioning. Projected pacemaker longevity at 1 month was strongly correlated with the 12-month estimate, and exceeded 13 years in >60% of patients. Conclusion These algorithms for automatic management of pacing output ensure patient safety in the event of a huge increase of pacing threshold, while enabling maximization of battery longevity. Their applicability is quite broad in an unselected pacemaker population irrespectively of lead choice and service of life.

Left atrium posterior wall (LAPW) is an essential target for transcatheter radiofrequency ablation (RFA) of atrial fibrillation (AF), but poses problems due to retro-atrial structures potentially damaged by RF. Intracardiac echocardiography (ICE) can be integrated with the 3D electro-anatomical map and can give unique real-time anatomical information about all closely-located peri-cardiac structures. The present study aimed to automatically detect dynamic oesophagus position and its spatial relationship from the LAPW by ICE during RFA. A fast algorithm based on the evaluation of gray-level intensity distribution in the image and was developed to detect distal and proximal oesophagus boundaries. The algorithm was tested in 15 ICE acquisitions. The detected oesophagus boundaries and those manually traced (MT) were compared and in 5 ICE sequences, dynamic tracking of proximal oesophagus boundary was performed. Mean analysis time was 4.5 sec/frame. Detected oesophagus wall positions were in good agreement with MT. Mean minimum dynamic distance between LAPW and oesophagus proximal wall during acquisition was 0.3±0.2mm (range: 0.0–0.6mm). This technique allows automated and accurate dynamic detection of LAPW and oesophagus position in ICE sequences. It represents a first step for dynamic quantification of oesophagus real-time position' changes and its distance from the LAPW to prevent oesophagus injuries.