bluuebunny/crossref_metadata_2025 huggingface dataset:
Therapieentwicklungen bei der Alzheimer-Krankheit
Authors: Grimmer Timo
Published: May 2022

Die Entwicklung neuer Therapien zur Behandlung der Alzheimer-Krankheit ist ein
Fokus der weltweiten Arzneimittelforschung. Es wird an potenteren Therapien zur
symptomatischen Behandlung, insbesondere zur Behandlung von
Verhaltensstörungen, aber auch an Medikamenten, die in die
Pathophysiologie der Erkrankung eingreifen, geforscht, mit dem Ziel, das
Voranschreiten der Alzheimer-Krankheit aufzuhalten oder zumindest zu
verlangsamen. Dazu verlagert sich der Schwerpunkt der Identifikation von
Menschen mit Alzheimer-Krankheit in Stadien der Prä-Demenz wie das der
leichten kognitiven Störung (Mild Cognitive Impairment, MCI oder nahezu
gleichbedeutend beginnende Alzheimer-Demenz: prodromal AD) oder gar in
asymptomatische Stadien. Bisher ermutigendste Ergebnisse liegen für den
Ansatz der passiven Immunisierung mittels monoklonaler Antikörper gegen
Aβ42 vor. Bisher gelang es nicht, mit mehreren abgeschlossenen
zulassungsrelevanten Studien statistisch signifikante Unterschiede auf den
primären Zielparametern zu demonstrieren. Der Antikörper gegen
Amyloid Aducanumab erhielt, basierend auf der Reduktion von Amyloid, eine
vorläufige Zulassung mit Auflagen in den USA; das Zulassungsverfahren
für Europa ist noch im Gange. Die gegenwärtigen
pharmakologischen Ansätze zur Behandlung der Alzheimer-Krankheit bieten
einen begrenzten symptomatischen Nutzen. Bisher ist noch keine
verlaufsverzögernde Behandlung gegen die Alzheimer-Krankheit in
Deutschland auf dem Markt. Daher ist zu empfehlen, Patienten, insbesondere in
prä-dementiellen Stadien oder im Stadium der beginnenden
Alzheimer-Demenz, eine Teilnahme an klinischen Studien zu empfehlen, um die
Entwicklung von neuen und besser wirksamen Medikamenten zur Behandlung der
Alzheimer-Krankheit, die dann vielen Patienten zu Gute kommen können, zu
beschleunigen.
Plasmon-induced coherence, exciton-induced transparency, and Fano interference for hybrid plasmonic systems in strong coupling regime
Authors: Scott Zoe , Muhammad Shafi , Shahbazyan Tigran V.
Published: May 2022

We present an analytical model describing the transition to a strong coupling regime for an ensemble of emitters resonantly coupled to a localized surface plasmon in a metal–dielectric structure. The response of a hybrid system to an external field is determined by two distinct mechanisms involving collective states of emitters interacting with the plasmon mode. The first mechanism is the near-field coupling between the bright collective state and the plasmon mode, which underpins the energy exchange between the system components and gives rise to exciton-induced transparency minimum in scattering spectra in the weak coupling regime and to emergence of polaritonic bands as the system transitions to the strong coupling regime. The second mechanism is the Fano interference between the plasmon dipole moment and the plasmon-induced dipole moment of the bright collective state as the hybrid system interacts with the radiation field. The latter mechanism is greatly facilitated by plasmon-induced coherence in a system with the characteristic size below the diffraction limit as the individual emitters comprising the collective state are driven by the same alternating plasmon near field and, therefore, all oscillate in phase. This cooperative effect leads to scaling of the Fano asymmetry parameter and of the Fano function amplitude with the ensemble size, and therefore, it strongly affects the shape of scattering spectra for large ensembles. Specifically, with increasing emitter numbers, the Fano interference leads to a spectral weight shift toward the lower energy polaritonic band.
Large-scale and high-depth three dimensional scanning measurement system and algorithm optimization
Authors: Zhang Fan , Li ZhenYang , Zhang Liansheng , Cheng Rongjun , Huang Qiangxian , Li Ruijun , Wang Chaoqun
Published: May 2022

Tapping scanning mode is an important method for measuring surface topography at the nanometer scale. It is widely used because it can eliminate lateral force and reduce damage to the tested sample. Research on three dimensional (3D) scanning technology with a large range and high depth-to-width ratio has important practical significance and engineering application value because the current scanning probe microscope has the limitations of small measurement ranges and weak Z-direction measurement ability. The high-frequency resonance of the quartz tuning fork, combined with the tungsten stylus, is used in this paper. It has the ability to measure the surface profile of the microdevice with a large aspect ratio. The proposed 3D scanning measurement system has realized a microstructure measurement with a depth of ∼58 µm. The entire measuring range is 400 × 400 × 400 µm3, and the vertical resolution reaches 0.28 nm. The system can accurately obtain the 3D surface topography of the microfluidic biochip. In addition, a sliding window algorithm (SWA) based on errors in the scanning process and low scanning efficiency is proposed. Compared with the point-by-line scanning algorithm, the proposed SWA reduces the mean value of the squared residuals of the 3D profile by 7.70%, thereby verifying the feasibility of the algorithm. The 3D scanning measurement system and the algorithm in the tap mode provide an important reference for the 3D topography measurement of microstructures with large aspect ratios.
Simulation of surfactant adsorption at liquid–liquid interface: What we may expect from soft-core models?
Authors: Faria Bruna F. , Vishnyakov Aleksey M.
Published: May 2022

The present work attempts to systematically explore the surfactant sorption at liquid–liquid interfaces with coarse-grained models targeting thermodynamic properties of reference liquid solutions. We employ dissipative particle dynamics with soft-core forcefield tested against experimental data on micellization of surfactants in water, and the previous results are reproduced in this work. We consider three different nonionic surfactants: hexaethylene glycol monododecyl ether (C12E6), 2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol) known as Triton X-100 (TX-100), and two alkyl glucoside surfactants (CnG1) with n-alkane tail fragments and a saccharide hydrophilic head at decane–water and toluene–water interfaces. For TX-100, we composed a model based on the literature forcefield and found good agreement with the experimental critical micelle concentrations (CMCs). The head–head interactions are of different origins for different surfactant groups: entropic repulsion between ethylene oxide chains of C12E6 and TX-100, and more chemically specific and complex interactions between the maltose heads of alkyl glucosides. We interpret our results with the Redlich–Peterson equation of monolayer adsorption in order to relate the adsorption to the bulk concentration of the surfactant and the interfacial tension. The densities of the adsorbed monolayer at CMC mostly agree with the experimental data, and a reasonable agreement was obtained for the interfacial tension at CMC. At the same time, we found significant discrepancies between the simulated and experimental adsorption isotherms. We explain them by the oversimplified forcefield: when the parameters are fitted to the free energies of bulk solutions, they may not correctly reproduce the interfacial free energies.
Photonic cavity mode tuning in porous silicon-based microcavities by He+ and H+ ion irradiation
Authors: Verma Chandra Prakash , Kandasami Asokan , Kanjilal D. , Vijaya Prakash Gaddam
Published: May 2022

The present investigation reports the optical characteristics of the porous Si (PSi) based microcavities before and after energetic He+ and H+ ion irradiations. These PSi microcavities were fabricated by the galvanostatic electrochemical etching process and irradiated with 35 keV He+ and H+ ions with three different ion fluences: 1 × 1015, 5 × 1015, and 1 × 1016 ions/cm2. Significant color contrast is evident in the reflection images after ion irradiation. These reflection spectra of the optical microcavities are systematically investigated before and after ion irradiations. The dominant resonant cavity peak of the microcavity shows a notable shift of ∼28–48 and ∼17–26 nm toward the higher wavelength region with He+ and H+ ion irradiations at various ion fluences, respectively. The relative changes in the cavity wavelengths are about ∼5%–10% and ∼3%–5% for He+ and H+ ion irradiations, respectively. The redshift in the reflectance spectra is attributed to modification in the refractive index of microcavities induced by He+ and H+ ions. These experimental results compare well with the ion propagation and transfer matrix method simulations. The observed changes in the optical properties arise due to surface modification of the Si–Si and Si–O bonds and thereby refractive index modification of individual PSi layers of the microcavity. This study establishes that low-energetic ions produce broadly optically tunable and photonic structures suitable for optoelectronic applications.
Substrate-dependence of monolayer MoS2 thermal conductivity and thermal boundary conductance
Authors: Gabourie Alexander J. , Köroğlu Çağıl , Pop Eric
Published: May 2022

The thermal properties of two-dimensional (2D) materials, such as MoS2, are known to be affected by interactions with their environment, but this has primarily been studied only with SiO2 substrates. Here, we compare the thermal conductivity (TC) and thermal boundary conductance (TBC) of monolayer MoS2 on amorphous (a-) and crystalline (c-) SiO2, AlN, Al2O3, and h-BN monolayers using molecular dynamics. The room temperature, in-plane TC of MoS2 is ∼38 Wm−1 K−1 on amorphous substrates and up to ∼68 Wm−1 K−1 on crystalline substrates, with most of the difference due to substrate interactions with long-wavelength MoS2 phonons (<2 THz). An h-BN monolayer used as a buffer between MoS2 and the substrate causes the MoS2 TC to increase by up to 50%. Length-dependent calculations reveal TC size effects below ∼2 μm and show that the MoS2 TC is not substrate- but size-limited below ∼100 nm. We also find that the TBC of MoS2 with c-Al2O3 is over twice that with c-AlN despite a similar MoS2 TC on both, indicating that the TC and TBC could be tuned independently. Finally, we compare the thermal resistance of MoS2 transistors on all substrates and find that MoS2 TBC is the most important parameter for heat removal for long-channel (>150 nm) devices, while TBC and TC are equally important for short channels. This work provides important insights for electro-thermal applications of 2D materials on various substrates.
Dynamic evolution process from bipolar to complementary resistive switching in non-inert electrode RRAM
Authors: Duan Yiwei , Gao Haixia , Qian Mengyi , Sun Yuxin , Wu Shuliang , Guo Jingshu , Yang Mei , Ma Xiaohua , Yang Yintang
Published: May 2022

At present, the physical mechanism of complementary resistive switching (CRS) devices remains controversial. In this Letter, stable CRS can be achieved in Pt/AlOxNy/Ta resistive random access memory (RRAM). A dynamic evolution from bipolar resistive switching to CRS can be evidently observed in non-inert electrodes RRAM. The causes of CRS behavior are analyzed in detail, and these phenomena are attributed to the different oxidation degrees of the top electrode and propose that the transition state can be used as a signal for the emergence of CRS behavior. Moreover, the model is partially supported by measured switching behavior of the Pt/AlOxNy/TaOx device. This research contributes to the understanding of the CRS behavior physical mechanism in non-inert electrodes RRAM devices.
Linear stability of a rotating channel flow subjected to a static magnetic field
Authors: Sengupta Saunak , Ghosh Sukhendu
Published: May 2022

Magnetohydrodynamics is effective to control the instabilities of fluid flows. This control process is cost-effective and compact because it does not require extra mechanical components. In the present study, the effect of a constant uniform magnetic field on the linear stability of a rotating channel flow is investigated. The electromagnetic field is applied in the spanwise direction alongside the axis of rotation. The Hartmann and rotation numbers characterize the magnetic and rotational effects. The axial flow is governed by the centrifugal force, and the Coriolis force due to rotation makes the flow unstable at relatively low Reynolds numbers concerning spanwise disturbances. The modal instabilities of the flow are captured by solving the Orr–Sommerfeld–Squire eigenvalue problem. Numerical results confirm that the employed magnetic force has a prominent stabilizing role on the linear instabilities of the rotating channel flow. Notably, the higher Hartmann numbers suppress the temporal growth of the most unstable mode and decrease the area of neutral stability boundaries. The onset of rotational instability occurs at a higher critical Reynolds number for a stronger magnetic field. Further, the presence of Lorentz force restricts the co-existence of multiple unstable modes and the mode competition phenomenon, which results in structure modification of roll-cells and tardy secondary flow. The findings of this investigation would be useful in designing bio-medical and mechanical tools where the rotational instabilities are harmful. Furthermore, it is hoped that the obtained results will motivate the experimental verification and look for worthy applications.
Pseudomorphic growth of thick Al0.6Ga0.4N epilayers on AlN substrates
Authors: Rathkanthiwar Shashwat , Houston Dycus J. , Mita Seiji , Kirste Ronny , Tweedie James , Collazo Ramon , Sitar Zlatko
Published: May 2022

We report on the absence of strain relaxation mechanism in Al0.6Ga0.4N epilayers grown on (0001) AlN substrates for thickness as large as 3.5 μm, three-orders of magnitude beyond the Matthews–Blakeslee critical thickness for the formation of misfit dislocations (MDs). A steady-state compressive stress of 3–4 GPa was observed throughout the AlGaN growth leading to a large lattice bow (a radius of curvature of 0.5 m−1) for the thickest sample. Despite the large lattice mismatch-induced strain energy, the epilayers exhibited a smooth and crack-free surface morphology. These results point to the presence of a large barrier for nucleation of MDs in Al-rich AlGaN epilayers. Compositionally graded AlGaN layers were investigated as potential strain relief layers by the intentional introduction of MDs. While the graded layers abetted MD formation, the inadequate length of these MDs correlated with insignificant strain relaxation. This study emphasizes the importance of developing strain management strategies for the implementation of the single-crystal AlN substrate platform for III-nitride deep-UV optoelectronics and power electronics.
Mitigation of laminar separation flutter using active oscillation of local surface
Authors: Huang Guangjing , Dai Yuting , Yang Chao , Xia Yingjie
Published: May 2022

This work explores the mitigation effect of laminar separation flutter (LSF) using active oscillation of a local surface at Re = 77 000. Aerodynamic forces and flow field of a National Advisory Committee for Aeronautics (NACA) 0012 airfoil are obtained by numerical simulations using the γ−Reθ transition model. The local oscillation is considered as a harmonic motion of a single mode varying both in temporal and spatial domains. The control effects of oscillation positions, amplitudes, and frequencies on the pitch instability are investigated. The work done by aerodynamic moment per motion cycle when the airfoil undergoes prescribed harmonic pitch motion is defined to evaluate the control performance. The mitigation effect of LSF is demonstrated by a fluid–structure interaction (FSI) method. The results show that the oscillation region should be placed on 0.2c for small oscillation amplitude while the optimal oscillation position is 0.6c for large oscillation amplitude. The flow control mechanism is analyzed in terms of the flow structure. A series of vortices are formed and moved downstream under the effect of active oscillation of the local surface. These vortices suppress the formation of a large-scale laminar separation phenomenon, which improves the pitch stability. The frequency lock-in phenomenon occurs in a certain oscillation frequency range, and it can improve the control performance on the pitch instability. The results of FSI show that the active oscillation of the local surface can completely eliminate the LSF.
Using tensor network states for multi-particle Brownian ratchets
Authors: Strand Nils E. , Vroylandt Hadrien , Gingrich Todd R.
Published: May 2022

The study of Brownian ratchets has taught how time-periodic driving supports a time-periodic steady state that generates nonequilibrium transport. When a single particle is transported in one dimension, it is possible to rationalize the current in terms of the potential, but experimental efforts have ventured beyond that single-body case to systems with many interacting carriers. Working with a lattice model of volume-excluding particles in one dimension, we analyze the impact of interactions on a flashing ratchet’s current. To surmount the many-body problem, we employ the time-dependent variational principle applied to binary tree tensor networks. Rather than propagating individual trajectories, the tensor network approach propagates a distribution over many-body configurations via a controllable variational approximation. The calculations, which reproduce Gillespie trajectory sampling, identify and explain a shift in the frequency of maximum current to higher driving frequency as the lattice occupancy increases.
Cardiac sympathetic-vagal activity initiates a functional brain–body response to emotional arousal
Authors: Candia-Rivera Diego , Catrambone Vincenzo , Thayer Julian F. , Gentili Claudio , Valenza Gaetano
Published: May 2022

Significance

We investigate the temporal dynamics of brain and cardiac activities in healthy subjects who underwent an emotional elicitation through videos. We demonstrate that, within the first few seconds, emotional stimuli modulate heartbeat activity, which in turn stimulates an emotion intensity (arousal)–specific cortical response. The emotional processing is then sustained by a bidirectional brain–heart interplay, where the perceived arousal level modulates the amplitude of ascending heart-to-brain neural information flow. These findings may constitute fundamental knowledge linking neurophysiology and psychiatric disorders, including the link between depressive symptoms and cardiovascular disorders.
Modified climbing fiber/Purkinje cell synaptic connectivity in the cerebellum of the neonatal phencyclidine model of schizophrenia
Authors: Veleanu Maxime , Urrieta-Chávez Beetsi , Sigoillot Séverine M. , Paul Maëla A. , Usardi Alessia , Iyer Keerthana , Delagrange Marine , Doyle Joseph P. , Heintz Nathaniel , Bécamel Carine , Selimi Fekrije
Published: May 2022

Significance

Synaptogenesis and neural network remodeling are at their maximum during the perinatal period of human brain development. Perturbations of this highly sensitive stage might underlie the etiology of neurodevelopmental disorders. Subchronic neonatal administration of phencyclidine, a drug of abuse, has been used to model schizophrenia in rodents. In this model, we found specific long-term synaptic changes in Purkinje cells and transient gene expression changes in the cerebellum. While transient increased neuronal activity in the cerebellum, induced using chemogenetics, reproduces some phencyclidine-induced molecular changes, it is insufficient to reproduce the long-term synaptic effects. Our results show the complex mechanism of action of phencyclidine on the development of neuronal connectivity and further highlight the potential contribution of cerebellar defects in psychiatric diseases.
Translingual practices and national identity mediated in the semiotized digital spaces
Authors: Sultana Shaila
Published: May 2022

Considering the contradictions in the structured and static approaches to the nation and national identity observed world-wide and fluid trans- approaches to language in applied linguistics and sociolinguistics, the paper explores how national identity is constructed and sustained nowadays, specifically in digital spaces both discursively and non-discursively. Based on the notion of ‘practice’ by Theodore Schatzki (2002), the paper focuses on the translingual practices in relation to national issues and events in Bangladesh drawn from digital spaces through a virtual ethnography. The findings in this paper show that translingual practices and national identity may apparently seem fluid in digital spaces. However, actors nurture beliefs, values, and ideologies in their translingual practices with reference to a territory-based notion of nation, religion, and national identity. Their discursive construction of nation and national identity also seems entangled with a non-discursive bundle of activities and symbolic and material artefacts within material arrangements of spaces. Verbal violence and terrorism accentuating nationalism get immediacy and are concretized in materially mediated semiotized spaces. With an immediate focus on spatial dynamics, while acknowledging the ethos of the post-structuralist approach to language, the paper, hence, indicates the necessity of transgressing the ‘logocentrism’ in language and identity research in applied linguistics and contributing to the recent development in the post-humanist applied linguistics.
Influencing mechanism of trace elements on quasi-static ignition of TiZrHf-based high-entropy alloys
Authors: Chen Chuang , Guo Yuyang , Gao Renkui , Guo Kai , Chang Mengzhou , Han Yafei , He Liping , Tang Enling
Published: May 2022

Quasi-static compression experiments of TiZrHf-based high-entropy alloys with different trace elements (Al, Cu and Ni) are performed. The microscopic morphology and phase structure of the samples are characterised. The critical stress is determined by the fracture criterion combined. The ignition processes during the quasi-static compression process are collected, and the ignition gestation period and duration are obtained. The results show that the samples experience elastic deformation, strengthening and fracture. The failure mode is a brittle fracture. The reaction of TiZrHfCu0.3 is more intense than TiZrHfAl0.3 and TiZrHfNi0.3, and the ignition critical stress is the highest. The ignition of high-entropy alloys is induced by the joint action of crack tip discharge and chemical bond fracture in the process of crack initiation and propagation.
Effects of a single impurity in a Luttinger liquid with spin–orbit coupling
Authors: Bahovadinov M S , Matveenko S I
Published: May 2022

In quasi-1D conducting nanowires spin–orbit coupling destructs spin–charge separation, intrinsic to Tomonaga–Luttinger liquid (TLL). We study renormalization of a single scattering impurity in a such liquid. Performing bosonization of low-energy excitations and exploiting perturbative renormalization analysis we extend the phase portrait in K

σ
− K

ρ
space, obtained previously for TLL with decoupled spin–charge channels.
Emergent O(4) symmetry at an one-dimensional deconfined quantum tricritical point
Authors: Xi Ning , Yu Rong
Published: May 2022

We show an O(4) symmetry emerges at a deconfined quantum tricritical point of a valence bond solid (VBS) and two ferromagnetic phases in an S = 1/2 frustrated spin chain by combining analytical analysis and numerical calculations with the time evolution of infinite matrix product states. With this symmetry, the valence-bond solid and the three magnetic order parameters form an O(4) pseudovector in the infrared limit, and can continuously rotate into each other. We numerically determine the location of the quantum tricritical point and study the scaling of the correlation functions of the O(4) vector components and associated conserved currents. The critical behaviors of these correlation functions are all in accord with field theoretical results. The emergent O(4) symmetry at the tricritical point is justified by the integer value of the scaling dimension of the emergent Noether conserved currents. Our findings not only give direct evidence of such a high emergent symmetry at an one-dimensional VBS to magnetic transition but also shed light on exploring emergent symmetries in higher dimensions.
C22 SYNCOPE UNIT AND REMOTE CONTROL IN THE ERA OF COVID–19 PANDEMIC: EXPERIENCE OF A SINGLE CENTER
Authors: Ferrieri A , Dentico A , Epicoco G , Carretta F , D‘Agostino C , Carretta D
Published: May 2022

Introduction

During the pandemic, many Syncope Units were closed due to inclusion of them and staff in Covid departments. In our experience, in order to meet the numerous requests of patients suffering from syncope, the care strategy was chosen to carry out all outpatient procedures within a single access. The use of this protocol made it possible to satisfy user requests, breaking down all barriers, including the fear of Covid–19.

Materials and Methods

The procedural process used in this period at our O.U. was: initial evaluation, execution of Active Stand Test, carotid sinus massage and implantation of loop recorder in a single access. Immediately after implantation, the patient was equipped with remote monitoring. Patients without events were followed only remotely and underwent telephone follow–up approximately every 3 months to update the center on their general state of health and any symptoms. In patients with events, the individual events were examined by the cardiologist and, by telephone follow–up, the presence of symptoms was assessed, correlating the recorded event with the reported symptom. These were subsequently summoned to the clinic.

Results

With this operating model in the years 2020/2021 we managed 53 patients in the Syncope Unit. Of these, 5 underwent PM implantation for loop recorder’s remote monitoring of the paroxysmal AVB, and one patient, for the detection of major ventricular arrhythmias, was protected with Life Vest pending completion of cardiological screening. The remaining patients, thanks to the remote control, are constantly followed at home and monitored with periodic telephone follow–up.

Conclusions

In line with the literature, also in our ER there was a notable reduction in accesses for syncope. Our operating model was virtuous as it served to decongest the ER and the wards, concentrating all patients with syncope in our Syncope Unit and also reducing the number of tests necessary to arrive at an etiological diagnosis of syncope. The Covid–19 pandemic has accelerated the transformation process of the Syncope Unit which is no longer just an elective place for the diagnosis of syncope, but also a fundamental reference for the remote control of ICM wearers.
C27 SHOCKWAVE DEFERRED USE IN A CASE OF INFERIOR STEMI
Authors: Priolo L , Ferrarello S , Buccheri D , Lombardo R , Vinci D
Published: May 2022

A 62–years–old female patient, smoker, hypertension, dyslipidemia and TIA in history, was admitted for inferior STEMI; urgent coronary angiography from radial access was done, revealing diffuse calcific coronary artery disease with thrombotic occlusion of the proximal right coronary artery. Primary PCI was done with a direct implantation of a 3,0/24 mm drug–eluting stent. The stent expansion was not optimal in the mid–portion, due to severe calcification, requiring then post–dilatations. Nevertheless, the use of several non–compliant balloons (3,0/12 mm, 3,0/8 mm, 3,0/6 mm, 3,25/12 mm) was not effective to fully expand the stent, even dilating at very high pressure (rupturing one of the balloon). A ventricular fibrillation episode complicated the procedure, promptly resolved. After the stenting, even if not fully expanded, TIMI 3 flow was gained, with ST segment elevation resolution, in a quite asymptomatic patient; no more devices were available, so the procedure was stopped and the patient transferred in the coronary care unite. A second procedure was scheduled with the support of the intravascular lithotripsy device (Shockwave). Through the radial access the second PCI was done, using at first the Shockwave balloon 2,5/12 mm, with its total 8 treatments; then the Shockwave balloon 3,0/12 mm was used, effective at the seventh treatment in the final rupture of the calcific lesion, obtaining the full expansion of the stent. A good final angiographic result was documented, the patient tolerated very well the procedure.
C44 VENTRICULAR TACHYCARDIA IN PATIENT WITH PSEUDOISCHEMIC VENTRICULAR SCAR
Authors: Agostini N , Giraldi M , Orsida D , Caico S
Published: May 2022

We describe a case of 76 years old men. He was referred to emergency room for chest pain and short of breath. The medical history escluded pre–existent miocardial infarction, no history of fever and chest pain has been declared,.The electrocardiogram (ECG) showed a 200 pbm tachycardia with right bundle branch and right axial deviation. The transition was in V4 (Fig. 1). The tachycardia was not tolerated and after ineffective administration of amiodarone, the tachycardia was terminated by DC shock (200 J synchronized). We performed an echocardiogram with evidence of minimal ventricular dilatation, the inferior–posterior–lateral akinesia, inferior–posterior scar and severe reduction of ejection fraction (about 30%). For better characterization of the scar, we performed cardio magnetic resonanc imaging with evidence of significative thinning of the left ventricle free wall and trasmural LGE of the of left ventricle free wall suggest ischemic myocardial injury (Fig. 2 a,b,c,d,e). The coronary arteriography was performed without evidence of critical coronary stenosis.We decide to implant a single lead ICD. After one month, because of recurrence of tachycardia, we performed the electrophysiological study. We induced clinical ventricular tachycardia and the electroanatomical mapping highlighted an area of anomalous potentials extended in the infero–posterior and lower–basal region more at the epicardial level. In these areas, at the epicardial level, late potentials were highlighted and the ablation performed making the tachycardia no longer inducible. Despite of evidence of pseudo–ischemic scar localized at the basal portion of ventricle at the cardiac MRI, no critical coronary stenosis has been demonstrated and the arrhythmogenic substrate was exclusively epicardic. The preliminary hypothesis was a MINOCA, not of recent onset considering the negativity of myocardial enzymes at the admission and the absence of acute ischemic changes on post cardioversion ECG.We have therefore also considered forms of previous extensive myocarditis however with the limited longitudinal extension. From what has been described in the literature, the MRI images could also be attributable to a form of left ventricle arrhythmogenic dysplasia even in the absence of involvement of the apical portions. Forms of infiltrative cardiomyopathies such as sarcoidosis should be excluded due to the lack of involvement of the interventricular septum.
C87 THE SHORT–TERM PROGNOSTIC SIGNIFICANCE OF BASELINE TROPONIN LEVELS IN PATIENTS HOSPITALIZED FOR COVID–19
Authors: Di Maio F , Baldin G , Todde N , Volpi N , Basan L , Vannucci V , Ruzittu G , Pisanu A , Seddone S , Santoru M , Delogu G , Favuzzi A , Porcu M
Published: May 2022

Background

Troponin (TN) is the biomarker of choice for the detection of cardiomyocite injury. Elevation of TN has been noted in COVID–19 patients (pts), implicating myocardial injury as a possible pathogenic mechanism contributing to disease severity.

Aim

To assess the in–hospital prognostic significance of baseline TN levels in COVID–19 pts. Methods. The data of 192 consecutive COVID–19 individuals (mean age 70±15 yrs, 54.6% males) hospitalized in a single institution were retrospectively analysed. According to the baseline TN–I levels (normal value up to 34 pg/ml), the whole population was divided into normal (Group A) and elevated (Group B) TN–I. Demographic parameters, clinical history, pharmacological treatments and laboratory data at the admission were evaluated. The length–of–stay, rate of orotracheal intubation, non–invasive ventilation and in–hospital mortality were considered as prognostic parameters.

Results

One–hundred–fifty–seven pts belonged to Group A, while thirty–five pts to Group B. Group A pts were significantly younger (67±14 vs 79 ±12 yrs, p < 0.001). As expected, a better renal profile was observed in pts with normal TN–I levels (eGFR 82±25 ml/m’ in Group A vs 48±30 ml/m’ in Group B, p < 0.001). No differences were noted between the two groups in the prevalence of diabetes, previous CAD, hypertension, ACE/ARBs treatment. The length–of–stay was similar (21±11days in Group A vs 19±17 days in Group B, respectively, p=ns). Also, the need for orotracheal intubation (11.4% vs 11.5% p=ns) and non–invasive ventilation (26.8% vs 28.6%, p=ns), were not significantly different between Group A and Group B. However, the in–hospital mortality was considerably lower in pts with normal baseline TN–I, as compared to those with a definite level of cardiomyocyte damage (20/157 Group A pts, 12.7%, vs 15/35 Group B pts, 42.9%, p < 0.001).

Conclusion

Our data demonstrate that high TN–I baseline level upon admission should be considered as a strong prognostic parameter in pts hospitalized for COVID–19. In our population, this observation seems not to be related to the different comorbidities, except for the renal function profile.
P11 QUICK PREVENTION OF THE POTENTIALLY SERIOUS CONSEQUENCES OF ELECTROMAGNETIC INTERFERENCE ON A ICD PATIENT THANKS TO THE REMOTE MONITORING SYSTEM OF THE DEVICE
Authors: Fais L , Floris R , Angei A , Farris F , Frau B , Giau G , Racis M , Delogu G
Published: May 2022

Clinical Case

We report the case of a 84–year–old female patient suffering from post–infarct heart disease with severe systolic dysfunction, wearing a dual–chamber defibrillator in secondary prevention because she had previously presented an episode of monomorphic ventricular tachycardia. After the implant, the patient was enrolled in the remote monitoring service of the device and constantly followed by our team. After a few months, at the remote control we found repeated episodes of very short duration of an alarm recognized by the device as ventricular arrhythmia in the VF window. Contrary to the arrhythmic interpretation of the device, the analysis of the EGM by the medical and nursing staff highlighted an electromagnetic interference defined by the type of signal, the presence of the same in all channels and by the lack of correlation with the underlying heart rhythm. The sensing of the ventricular lead was 5–6 mV, at the lower limits but stable over time, the other parameters were optimal. The patient was promptly contacted and questioned about the circumstances and symptoms: she was asymptomatic and we found that the interference came in conjunction with the use of a cordless telephone. The alarm was related to the electromagnetic field generated by the phone and the woman was asked to stop using the device with subsequent absence of device alarms. Electromagnetic interference in defibrillators can be a cause of potentially serious inappropriate therapies (ATP, pacing and shock), the analysis and correct interpretation of the EGM by the clinician is essential for the prevention of the same. Thanks to the efficiency of the remote monitoring service, the risk of serious consequences for our patient was avoided. Subsequently the lead was repositioned due to a worsening of the sensing, but even before the re–intervention there was no longer any false alarm thanks to the absence of the environmental source of interference. The remote monitoring service applied to implantable defibrillation systems is a valuable tool for identifying lead problems or, as in this case, environmental problems, and toprevent, thanks to rapid intervention, further potentially serious complications.
P13 COMPLETE ATRIOVENTRICULAR BLOCK IN A 52–YEAR–OLD MAN ASSOCIATED WITH LYMPHATIC CANCER WITH CARDIAC INVOLVEMENT
Authors: Massacesi C , Di Saverio M , Iadanza Lanzaro B , Rolando M , Befacchia G , Core A , Di Eusanio M , Di Francesco G , De Berardis L , Gregori G , Napoletano C
Published: May 2022

A 52–year–old man arrived at the local emergency room for worsening dyspnea and asthenia, present for about a month, but significantly worsening during the night of the access. The ECG (Figure 1) revealed complete AtrioVentricular Block (ABV) with a narrow–QRS junctional escape rhythm, with a heart rate of about 30 beats per minute (bpm). The other vital parameters were within the normal limits and no anomalies were detected on the physical examination. Medium–dose intravenous isoprenaline infusion was immediately started, with an increase in the junctional escape rate up to 50 bpm. The patient also underwent chest x–ray, which showed interstitial thickening in the pulmonary hilus, which was judged to be nonspecific. The blood chemistry was normal and the echocardiogram (Figure 2) did not show any abnormalities. Since there were no apparent reversible causes of the complete AV block, on the next day, a bicameral pacemaker was implanted via the left cephalic vein. The procedure was uneventful and the patient was discharged home two days later, in good general condition. Eight days after the discharge, surgical wound control and pacemaker control were performed, with completely normal parameters. About 15 days after the discharge the patient went back to the local emergency room for dyspnea and fever. Chest Computed Tomography (CT) without contrast medium was performed, which revealed the presence of widespread pathological mediastinal lymphadenopathy. Therefore, the patient was admitted to the internal medicine ward. An in–depth diagnostic was performed first with thoraco–abdominal angio–CT, then with Positron Emission Tomography (PET)–CT (see Figure 3), which revealed the presence of diffuse areas of fixation of the radio–drug (18F–Fluorodeoxyglucose –FDG–), at the ilo–mediastinal, hepatic, pulmonary, retrocrural, retrocaval, iliac, supra and subclavicular, and also cardiac area (activation of interatrial brown fat and between aortic root and the superior vena cava). The patient was therefore transferred to another hospital for diagnostic investigations and lymphoma therapy. In the light of the picture that emerged, the arrhythmological disease was considered to be referred to the cardiac involvement of the oncological disease; to date there are few similar cases described in the literature. Legend of the figures: Figure 1: ECG at the admission Figura 2: Echocardiogram at the admission Figura 3: PET / CT with myocardial areas of 18F–FDG fixation.
P27 MONOMORPHIC VENTRICULAR TACHYCARDIA INDUCED BY BLUNT CHEST TRAUMA IN A YOUNG MAN WITHOUT STRUCTURAL HEART DISEASE: A CASE REPORT
Authors: Casula M , De Toni C , Mameli S , Schintu B , Setzu A , Scalone A , Pasqualucci D , Tola G , Corda M
Published: May 2022

Introduction

Life–threatening ventricular arrhythmias secondary to chest trauma without structural cardiac damage (i.e. commotio cordis [CC]) are a rare but dramatic cause of sudden cardiac death. We present a case of fast ventricular tachycardia (VT) induced by blunt chest trauma in a healthy man during sports activity.

Case Presentation

A 22–year–old man, competitive soccer player, was admitted to our hospital for VT. A few hours before admission, after a heavy ball impact in the chest during a soccer match, he suddenly reported fast and regular palpitation with lightheadedness and dyspnea, without loss of consciousness. The emergency medical service was activated, and the evaluation revealed a hemodynamically tolerated monomorphic VT with a rate of almost 285 bpm (Fig.A). Amiodaron infusion was ineffective and sinus rhythm (SR) was restored by electrical cardioversion. At the time of admission, he was asymptomatic. Familiar history, past medical history and physical examination were unremarkable. ECG revealed regular SR, with minimal right bundle branch conduction delay (Fig.B). Blood samples showed normal blood cells count, electrolyte concentrations and liver, kidney, and thyroid function; seriate high sensitivity troponin I determinations were negative. Echocardiography and cardiac magnetic resonance showed normal findings. Computed tomography angiography excluded coronary anomalies. Exercise test revealed no signs of cardiac ischemia and no effort–induced arrhythmias. The fluoroscopy–free unipolar and bipolar voltage maps showed normal electrograms throughout the right ventricle (Fig.C). No sustained arrhythmias were induced by programmed ventricular stimulation. The patient was then discharged with the indication to cardiology follow–up and the advice to avoid contact sports activities.

Discussion

VT is a rare presentation of CC. It has been proposed that CC occurs when a chest strike timed at the upstroke of the T–wave causes both ventricular depolarization trigger and altered dispersion of repolarization, mainly via activation of KATP channels. In the absence of structural heart disease (SHD), the usual presenting rhythm is ventricular fibrillation and there are no accepted mechanisms to explain monomorphic VT in this context. Some authors reported monomorphic VT after chest trauma as the first manifestation of arrhythmogenic cardiomyopathy. Therefore, a careful follow–up will be needed to exclude future development of SHD in this patient.
P30 CARDIAC ARRESTS IN SPORTS: WHAT IS DIFFERENT COMPARED TO OTHER PUBLIC PLACES?
Authors: Compagnoni S , Gentile F , Baldi E , Mare C , Primi R , Bendotti S , Currao A , Contri E , Reali F , Bussi D , Facchin F , Centineo P , Savastano S
Published: May 2022

Introduction

Cardiac arrests in sports can involve professional athletes, amateurs, but also spectators of sports competitions. Sports facilities are the only ones for which the current law provides for the presence of an automatic external defibrillator (AED) and trained personnel, unlike other public places (schools, work, street, station, general public buildings) where it is only recommended.

Objective

To compare patient characteristics, presentation rhythm, bystander cardiopulmonary resuscitation (CPR), AED use before emergency medical services (EMS) arrival, and return of spontaneous circulation (ROSC) longer than 30 seconds in the Utstein category of out–of–hospital cardiac arrests (OHCAs) in sports compared to events in other public places.

Materials and Methods

We considered all the OHCAs occurred from 01/01/2015 to 31/12/2020 in the provinces of Pavia, Lodi, Cremona, Mantua and Varese (2400000 inhabitants), excluding the OHCAs occurred at home, in long–term care facilities and witnessed by the EMS.

Results

During the study period, 22 OHCAs occurred in sports and 552 in other public places (school, work, street, station, public buildings). The age is similar in the two groups [sport 59 years (IQR 53.5–66.7) vs other 63 years (IQR 51–75), p = 0.2]. In sports, there is a trend in favor of shockable rhythms (13/22=59% vs 185/552=33%, p = 0.1). The percentage of CPR performed by bystanders in sports is significantly higher than in other public places (20/22=91% vs 299/552=54%, p = 0.003), as the bystander AED use (11/22=50% vs 64/552=12%, p < 0.001) and bystander AED shock (7/22=31% vs 27/552=5%, p < 0.001) before EMS arrival. A ROSC greater than 30 seconds was obtained in 59% of OHCAs in sports, with a statistically significant difference compared to events in other public places (13/22=59% vs 166/552=30%, p = 0.015).

Conclusions

During sports competitions there is a greater ability to intervene in case of cardiac arrest, which determines a higher probability of obtaining ROSC, although in terms of age or presentation rhythm the patients are comparable to OHCA victims in other places public. These results suggest the need for an AED and trained personnel in other public places as well.
P32 SELF–LEARN IMPLEMENTATION OF ULTRASOUND FOR THE STUDY AND ULTRASOUND–GUIDED PUNCTURE OF VASCULAR ACCESSES IN THE IMPLANTATION OF PACEMAKERS AND IMPLANTABLE DEFIBRILLATORS
Authors: Lilli A , Solarino G , Della Tommasina V , Del Meglio J , Comella A , Poddighe R , Canale M , Bertini L , De Caro F , Christou A , Ferrali E , Tognarelli A , Coviello K , Baratto M , Casolo G
Published: May 2022

Background

The vascular access represents a crucial phase in the management of complications related to the implantation of devices. After the use of the axillary vein, which allows the elimination of intrathoracic complications as well as the subclavian crush of the catheters, the ultrasound–guided approach could represent the next step for the reduction of vascular complications.

Experience

All implants performed (n = 86) by an independent operator who implemented ultrasound to minimize complications related to central access were reviewed. During the first phase, the ultrasound–guided approach involved the study of vascular accesses before the start of the implant. The assessment took place before the preparation of the sterile field, for the localization of the axillary approach and for the study of the anatomical variants. It was immediately followed by the use of skin marks. The use of markers made it possible to attempt surgical isolation of the cephalic vein as a first approach. In case of failure, or the need for multiple accesses, the transition to central access could be facilitated by the presence of skin markers. This approach have not significantly modified the probability of successful axillary vein puncture without the use of venography (75% vs 71%, p NS). In the last phase all implants were performed with ultrasound–guided puncture with sterile technique before skin incision (n = 26). The procedures involved dual chamber (61%), single chamber (19%), CRTD (11%), dual chamber ICD. Ultrasound showed all cases of hypoplastic cephalic vein (15%). In the first three months of implementation, the success rate was 71.4% with 1 self–healing case of apical pneumothorax. In the following months the success rate rapidly increased to 94.1% (p < 0.05) with no pneumo or hemothorax. The median time to effective puncture was 28 seconds (8–450sec) in the second phase. It was possible to isolate the cephalic vein in 40% of cases for two or three chamber implants.

Conclusions

The ultrasound study of the accesses performed before the incision allows to identify the anatomy and to define the course of the axillary vascular system and its relationships. When performed with a sterile approach, it allows direct ultrasound–guided puncture before the surgical incision, with a high success rate from the early stages of implementation.