bluuebunny/crossref_metadata_2025 huggingface dataset:
Intrinsic V vacancy and large magnetoresistance in V1 — δ
Sb2 single crystal
Authors: Zhang Yong , Huang Xinliang , Zhang Jinglei , Gao Wenshuai , Zhu Xiangde , Pi Li
Published: October 2021

The binary pnictide semimetals have attracted considerable attention due to their fantastic physical properties that include topological effects, negative magnetoresistance, Weyl fermions, and large non-saturation magnetoresistance. In this paper, we have successfully grown the high-quality V1 – δ
Sb2 single crystals by Sb flux method and investigated their electronic transport properties. A large positive magnetoresistance that reaches 477% under a magnetic field of 12 T at T = 1.8 K was observed. Notably, the magnetoresistance showed a cusp-like feature at the low magnetic fields and such feature weakened gradually as the temperature increased, which indicated the presence of a weak antilocalization effect (WAL). In addition, based upon the experimental and theoretical band structure calculations, V1 – δ
Sb2 is a research candidate for a flat band.
Long-term nitrogen deposition does not exacerbate soil acidification in tropical broadleaf plantations
Authors: Huang Juan , Zhang Wei , Li Yuelin , Wang Senhao , Mao Jinhua , Mo Jiangming , Zheng Mianhai
Published: October 2021

Nitrogen (N) deposition induces soil acidification in natural forests; however, whether it increases soil acidity in tropical plantations with simple tree structures compared with natural forests remains unclear. This study aimed to investigate the effects of N deposition on the soil acidity of tropical broadleaf plantations dominated byAcacia auriculiformisandEucalyptus urophyllain South China, which has been enduring N deposition for over 30 years, and investigate the reasons for the changes in soil acidity. Long-term N addition did not affect soil acidity in the two plantations, with no significant changes in soil pH values, and exchangeable non-acidic and acidic cation concentrations. Long-term N deposition did not significantly affect the plant and total soil N concentrations, but significantly increased the soil nitrous oxide emission rates and total dissolved N concentrations in the soil solutions. Our findings indicate that most of the added N was lost via leaching and emissions, such that long-term N addition did not exacerbate soil acidification in broadleaf plantations, thereby providing novel insight into the effects of atmospheric N deposition on forest ecosystems. Overall, our study indicates that long-term N deposition does not always lead to soil acidification in tropical forests, as previously expected.
IABR Symposium 2021 meeting report: breath standardization, sampling, and testing in a time of COVID-19
Authors: Schmidt Alexander J , Salman Dahlia , Pleil Joachim , Thomas C L Paul , Davis Cristina E
Published: October 2021

Due to COVID-19 travel disruptions, the International Association of Breath Research hosted the planned 2021 Breath Summit virtually as a symposium with oral and poster presentations. The event was comprised of a week-long social media asynchronous online event for sharing research abstracts, posters and discussions. Subsequently, there were two days of real-time webinar platform interactions each featuring three technical presentations, open forum questions, answers, and commentary. The symposium was well attended and well received. It allowed the breath community to share new research and to reconnect with colleagues and friends. This report presents an overview of the topics presented and various salient discussion points.
Influence of extra chromium addition on the microstructure, hardness, and corrosion behaviour of high carbon ferrochrome FeCrV15 deposited through laser cladding on steel baseplate for tillage application
Authors: Aramide Basiru , Popoola Patricia , Sadiku Rotimi , Jamiru Tamba , Pityana Sisa
Published: October 2021

Laser cladding is an additive manufacturing technology utilised in surface strengthening, modification, and repair of components subjected to adverse working conditions, such as tillage tools, which is accomplished by adding functionally graded material with a remarkable limit to enhancing an engaged credited property of monolithic material that is superior and better than its monolithic counterparts. In this comparative study, FeCrV15 and FeCrV15 + Cr deposits were deposited on steel baseplate through Laser Additive manufacturing (laser cladding), and the hardness, microstructure and corrosion behaviour of the developed samples were examined and compared. The effect of extra addition of chromium on the corrosion behaviour of the high carbon ferrochrome FeCrV15 in 3.5 wt% NaCl solution was investigated. The morphologies of the microstructures were analysed with the Scanning Electron Microscope equipped with Energy Dispersion Spectroscopy (SEM/EDS), Optical microscope, x-ray diffractometer and Vicker microhardness tester. The result shows that extra chromium addition greatly influences the hardness, microstructural formation and corrosion behaviour of high carbon ferrochrome FeCrV15.
Drug delivery by SiC nanotubes as nanocarriers for anti-cancer drugs: investigation of drug encapsulation and system stability using molecular dynamics simulation
Authors: Faizi Atousa , Kalantar Zahra , Hashemianzadeh Seyed Majid
Published: October 2021

Since much attention has been paid to the targeted drug delivery system, using the molecular dynamics simulation, the present work has been devoted to clarify the potential of the silicon carbide nanotubes (SiCNTs) as a new carrier for the three common anti-cancer drugs temozolomide, carmustine, and cisplatin. Three zigzag single-walled nanotubes with different diameters, i.e. SiC(18,0), SiC(20,0), and SiC(22,0), in pure and decorated with the hydroxyl and carboxyl functional groups are selected to assess the effect of the functional groups as well as the diameter effect on the drug encapsulation process. The effects of binding energy, probability of finding the drugs along the nanotube length, mean square displacement, and body temperate as well as the zeta potential for the stability of the drug delivery system in the blood stream are evaluated. The results showed that the cisplatin does not encapsulate into the selected SiCNTs. However, the pure nanotubes show a high stability in the blood stream but the magnitude of their interaction energies with the temozolomide and carmustine drugs is less than −10 kcal mol−1, which does not guarantee that the drug will remain bonded to the nanotubes in the blood stream. Also the presence of the carboxyl functional group on the nanotube surface not only has no significant effect on the interaction energies but also decreases the stability of the drug delivery system. Decorating the edge nanotubes with the hydroxyl group causes the interaction between temozolomide and SiCNTs into chemisorption (−10 to −40 kcal mol−1) while the variation in binding energy of the carmustine is not remarkable. Finally, the zeta-potential results showed that the edge nanotubes decorated with the hydroxyl group due to a high stability in the blood stream as well as the strong interaction with the drugs temozolomide and carmustine is an appropriate carrier for the targeted drug delivery.
Productivity curve and social network analysis in science megaproject management
Authors: Bentley Phillip M
Published: October 2021

Megaprojects aimed at delivering next-generation, multi-billion euro scientific research facilities are complex and high-risk endeavours, requiring expert knowledge spanning a wide spectrum of technical and administrative fields. Such organisations tend to evolve organically, responding to technical and political challenges. They are almost certain to fail to meet expectations on schedule, budget, and deliverables. Whilst there have been illuminating ‘top-down’ phenomenological megaproject studies recently, this article reports a ‘bottom-up’ perspective on the emergence of these issues. Firstly, the staff productivity distribution curves are analysed at a European science megaproject, and a stratified culture is identified: there is a small, high productivity ‘clique’, and a vast, low-productivity group of ‘outsiders’ operating at only 50% of their potential. The social network is then analysed, revealing a dense decision-making group that is only tenuously connected to technical expert teams via hierarchy. Staff inefficiency is linked to superfluous roles in middle management, carrying increased bureaucratic burdens and a financial loss ∼10% of the annual salary budget. Corrective suggestions are given, for the current megaproject and future activities to mitigate these causes. This should help to reduce some of the overspend, schedule overrun, and reductions in ambition and scope that have become megaproject norms.
Some specific solutions to the translation-invariant N-body harmonic oscillator Hamiltonian
Authors: Willemyns Cintia T , Semay Claude
Published: October 2021

The resolution of the Schrödinger equation for the translation-invariant N-body harmonic oscillator Hamiltonian in D dimensions with one-body and two-body interactions is performed by diagonalizing a matrix

J

of order

N
−
1

. It has been previously established that the diagonalization can be analytically performed in specific situations, such as for

N
≤
5

or for N identical particles. We show that the matrix

J

is diagonal, and thus the problem can be analytically solved, for any number of arbitrary masses provided some specific relations exist between the coupling constants and the masses. We present analytical expressions for the energies under those constraints.
Magnetic nanomaterials-mediated cancer diagnosis and therapy
Authors: Liu Xiaoli , Zhang Huan , Zhang Tingbin , Wang Yanyun , Jiao Wangbo , Lu Xiaofeng , Gao Xiao , Xie Mengmeng , Shan Qingfeng , Wen Nana , Liu Chen , Lee Wee Siang Vincent , Fan Haiming
Published: October 2021

Magnetic nanomaterials have been widely used in various biomedical applications, which have seen accelerating interest since the breakthrough in the chemical synthesis of monodispersed iron oxide nanoparticles. Magnetic iron oxide nanoparticles (MIONs) possess excellent biocompatibility, and they can produce multiple physicochemical effects when exposed to magnetic fields. Due to this rapid development in MIONs for cancer diagnosis and therapy, it becomes necessary to present a comprehensive review paper from the biomedical engineering perspective. This review will present an overview of the recent synthesis methods used in the preparation of magnetic nanomaterials. We will then focus on the application of magnetic nanomaterials in imaging and therapy technology, and we will also evaluate their biosafety in vitro, in vivo, and clinical aspects. The therapeutic effects of magnetic theranostics, magnetocatalytic therapy, magnetically targeted therapy, and magnetothermal therapy under the guidance of imaging diagnosis will also be discussed in this review. Finally, we will briefly analyze the challenges of implementing magnetic nanomaterials as a nano-platform for imaging diagnosis and treatment, and we will also offer suggestions for future research in this field.
Differential resistance based self-sensing recurrent neural network model for position estimation and control of antagonistic Shape Memory Alloy actuator
Authors: Bhargaw Hari N. , Singh Samarth , Botre B A , Sinha Poonam
Published: October 2021

The paper presents the development and experimental investigation of recurrent neural network (RNN) based self-sensing position estimation (SSPE) model for shape memory alloy actuator (SMA). RNN is used as an estimator in the position feedback control loop to replace the external additional position sensor. The model was inspired by the physics-based analogy of the Mass-Spring-Damper (MSD) system for the antagonistic SMA wire actuator. Actuator displacement presents the hysteresis and non-linear dynamic relationship with observed differential resistance (sensing signal) during phase transformation. The resistance variation causes due to dissimilar resistivity between primary phases of SMA material. The RNN based estimation model was considered because it consists of memory elements for storing the processed information and feedback connections for dynamic modeling of the system. RNN was trained with input sensing signal and target displacement datasets. The estimation accuracy of the model was real-time evaluated during trajectory tracking of reference signals in the feedback control loop. A quantitative performance analysis is assessed in terms of correlation (ℛ), mean absolute error (MEA), and root mean square error (RSME) of the learned model along with the developed actuator system. The tracking results confirm the close agreement between estimated and measured displacement at a reasonable accuracy.
Is comprehensive geriatric assessment hospital at home a cost-effective alternative to hospital admission for older people?
Authors: Singh Surya , Gray Alastair , Shepperd Sasha , Stott David J , Ellis Graham , Hemsley Anthony , Khanna Pradeep , Ramsay Scott , Schiff Rebekah , Tsiachristas Apostolos , Wilkinson Angela , Young John
Published: October 2021

Background

hospital level healthcare in the home guided by comprehensive geriatric assessment (CGA) might provide a less costly alternative to hospitalisation for older people.

Objective

to determine the cost-effectiveness of CGA admission avoidance hospital at home (HAH) compared with hospital admission.

Design/intervention

a cost-effectiveness study alongside a randomised trial of CGA in an admission avoidance HAH setting, compared with admission to hospital.

Participants/setting

older people considered for a hospital admission in nine locations across the UK were randomised using a 2:1 randomisation schedule to admission avoidance HAH with CGA (N = 700), or admission to hospital with CGA when available (N = 355).

Measurements

quality adjusted life years, resource use and costs at baseline and 6 months; incremental cost-effectiveness ratios were calculated. The main analysis used complete cases.

Results

adjusting for baseline covariates, HAH was less costly than admission to hospital from a health and social care perspective (mean −£2,265, 95% CI: −4,279 to −252), and remained less costly with the addition of informal care costs (mean difference −£2,840, 95% CI: −5,495 to −185). There was no difference in quality adjusted survival. Using multiple imputation for missing data, the mean difference in health and social care costs widened to −£2,458 (95% CI: −4,977 to 61) and societal costs remained significantly lower (−£3,083, 95% CI: −5,880 to −287). There was little change to quality adjusted survival.

Conclusions

CGA HAH is a cost-effective alternative to admission to hospital for selected older people.
EDCNN: identification of genome-wide RNA-binding proteins using evolutionary deep convolutional neural network
Authors: Wang Yawei , Yang Yuning , Ma Zhiqiang , Wong Ka-Chun , Li Xiangtao
Published: October 2021

Motivation

RNA-binding proteins (RBPs) are a group of proteins associated with RNA regulation and metabolism, and play an essential role in mediating the maturation, transport, localization and translation of RNA. Recently, Genome-wide RNA-binding event detection methods have been developed to predict RBPs. Unfortunately, the existing computational methods usually suffer some limitations, such as high-dimensionality, data sparsity and low model performance.

Results

Deep convolution neural network has a useful advantage for solving high-dimensional and sparse data. To improve further the performance of deep convolution neural network, we propose evolutionary deep convolutional neural network (EDCNN) to identify protein–RNA interactions by synergizing evolutionary optimization with gradient descent to enhance deep conventional neural network. In particular, EDCNN combines evolutionary algorithms and different gradient descent models in a complementary algorithm, where the gradient descent and evolution steps can alternately optimize the RNA-binding event search. To validate the performance of EDCNN, an experiment is conducted on two large-scale CLIP-seq datasets, and results reveal that EDCNN provides superior performance to other state-of-the-art methods. Furthermore, time complexity analysis, parameter analysis and motif analysis are conducted to demonstrate the effectiveness of our proposed algorithm from several perspectives.

Availability and implementation

The EDCNN algorithm is available at GitHub: https://github.com/yaweiwang1232/EDCNN. Both the software and the supporting data can be downloaded from: https://figshare.com/articles/software/EDCNN/16803217.

Supplementary information

Supplementary data are available at Bioinformatics online.
The phosphorylated retinoid X receptor-α promotes diethylnitrosamine-induced hepatocarcinogenesis in mice through the activation of β-catenin signaling pathway
Authors: Sakai Hiroyasu , Yamada Yasuhiro , Kubota Masaya , Imai Kenji , Shirakami Yohei , Tomita Hiroyuki , Hara Akira , Shimizu Masahito
Published: October 2021

Previous studies have shown that phosphorylation of the retinoid X receptor-α (RXRα) is associated with the development of hepatocellular carcinoma (HCC). However, these findings were revealed using HCC cell lines that express phosphorylated-RXRα (p-RXRα) proteins; therefore, it remains unclear whether p-RXRα affects hepatocarcinogenesis in vivo. Therefore, to investigate the biological function of p-RXRα in vivo, we developed a doxycycline-inducible ES cell line and transgenic mouse, both of which overexpress the phosphomimetic mutant form of RXRα, T82D/S260D, in a doxycycline-dependent manner. We found that the development of liver tumors, especially high-grade adenoma and HCC, was enhanced in diethylnitrosamine (DEN)-treated T82D/S260D-inducible mice. Moreover, the increased incidence of liver tumors in the transgenic mice was attributable to the promotion of cell cycle progression. Interestingly, the expression of β-catenin protein and its target gene cyclin D1 was elevated in the liver tumors of DEN-treated T82D/S260D-inducible mice, concurrent with increased cytoplasmic and nuclear β-catenin protein expression, indicating its stabilization and transcriptional activation. These results indicate that p-RXRα promotes DEN-induced hepatocarcinogenesis in mice through the activation of the β-catenin signaling pathway, suggesting that p-RXRα may serve as a possible therapeutic target for HCC.
Prognostic values of exercise echocardiography and cardiopulmonary exercise testing in patients with primary mitral regurgitation
Authors: Coisne Augustin , Aghezzaf Samy , Galli Elena , Mouton Stéphanie , Richardson Marjorie , Dubois Denis , Delsart Pascal , Domanski Olivia , Bauters Christophe , Charton Marion , L'Official Guillaume , Modine Thomas , Vincentelli André , Juthier Francis , Lancellotti Patrizio , Donal Erwan , Montaigne David
Published: October 2021

Aims

To compare the clinical significance of exercise echocardiography (ExE) and cardiopulmonary exercise testing (CPX) in patients with ≥moderate primary mitral regurgitation (MR) and discrepancy between symptoms and MR severity.

Methods and results

Patients consulting for ≥moderate discordant primary MR prospectively underwent low (25 W) ExE, peak ExE, and CPX within 2 months in Lille and Rennes University Hospital. Patients with Class I recommendation for surgical MR correction were excluded. Changes in MR severity, systolic pulmonary artery pressure (SPAP), left ventricular ejection fraction (LVEF), and tricuspid annular plane systolic excursion were evaluated during ExE. Patients were followed for major events (ME): cardiovascular death, acute heart failure, or mitral valve surgery. Among 128 patients included, 22 presented mild-to-moderate, 61 moderate-to-severe, and 45 severe MR. Unlike MR variation, SPAP and LVEF were successfully assessed during ExE in most patients. Forty-one patients (32%) displayed reduced aerobic capacity (peak VO2 < 80% of predicted value) with cardiac limitation in 28 (68%) and muscular or respiratory limitation in the 13 others (32%). ME occurred in 61 patients (47.7%) during a mean follow-up of 27 ± 21 months. Twenty-five Watts SPAP [hazard ratio (HR) (95% confidence interval, CI) = 1.03 (1.01–1.06), P = 0.003] and reduced aerobic capacity [HR (95% CI) = 1.74 (1.03–2.95), P = 0.04] were independently predictive of ME, even after adjustment for MR severity. The cut-off of 55 mmHg for 25 W SPAP showed the best accuracy to predict ME (area under the curve = 0.60, P = 0.05).

Conclusion

In patients with ≥moderate primary MR and discordant symptoms, 25 W exercise pulmonary hypertension, defined as an SPAP ≥55 mmHg, and poor aerobic capacity during CPX are independently associated with adverse events.
From trivial to severe arrhythmias: the diagnostic role of multimodality imaging in inflammatory cardiomyopathy through a case series
Authors: Haddad Christelle , Herrera-Siklody Claudia , Porretta Alessandra Pia , Carroz Patrice , Pascale Patrizio , Pruvot Etienne
Published: October 2021

Background 

The diagnosis of inflammatory cardiomyopathy remains challenging in cases presenting with arrhythmia as sole manifestation. An early diagnosis is critical as it may prevent life-threatening complications such as sudden cardiac death and atrioventricular block (AVB). The diagnostic workup of suspected cases includes multimodality imaging that requires an adequate interpretation in order to limit the risk of overdiagnosis.

Case summary 

Herein, we report three cases presenting with various new-onset arrhythmias. The first patient was admitted for a third-degree AVB. The second patient suffered from a supraventricular tachycardia which degenerated into ventricular fibrillation. The third case was investigated for symptomatic premature ventricular complexes. No apparent heart disease was observed on standard exams (clinical, biological examinations, and echocardiography). However, cardiac magnetic resonance imaging (MRI) and nuclear imaging (68Ga-DOTATOC and/or 18F-FDG PET/CT) suggested an inflammatory substrate that seemed to correlate with the arrhythmic phenotype. Cardiac inflammation disappeared on immunotherapy for the first case and spontaneously for the third case.

Discussion 

These cases emphasize the incremental diagnostic yield of multimodality imaging to highlight myocardial inflammation. Nuclear imaging modalities may complement MRI by enabling the detection of active inflammation. The 18F-FDG PET/CT is well established for the diagnosis of cardiac sarcoidosis but its role remains to be clarified for the diagnosis of myocarditis. An alternative radiotracer, 68Ga-DOTATOC, appears promising by overcoming the main limitation of 18F-FDG but its specificity is not yet well established. The role of functional investigations is discussed as well as the benefit of immunosuppressive treatments.
Mechanoenergetic coupling in heart failure with preserved, mid-range and reduced left ventricular ejection fraction
Authors: Hansen K B , Sorensen J , Hansson N H , Nielsen R , Larsen A H , Frokiaer J , Tolbod L P , Gormsen L C , Harms H J , Wiggers H
Published: October 2021

Background

Heart failure (HF) classification based on left ventricular ejection fraction (LVEF) can vary because of changes in filling pressures, afterload, and contractile function. 11C-acetate positron emission tomography (PET) provides a load-independent measure of myocardial external efficiency (MEE) by simultaneous assessment of myocardial oxygen consumption (MVO2), cardiac work, left ventricular mass (LVM), end-systolic wall stress (ESWS), and myocardial blood flow (MBF).

Purpose

We aimed to characterize mechanoenergetic derangements in patients with HF and to study its interrelation with age, sex and obesity.

Methods

MEE was measured in 121 participants with 11C-acetate PET, and LVEF was acquired with echocardiography. We investigated healthy controls (n=20) and patients with HF and reduced LVEF <40% (HFrEF; n=25), mid-range LVEF 40–49% (HFmrEF; n=23), as well as patients with asymptomatic aortic valve stenosis (AS) and LVEF ≥50% (AS-asymp; n=38), and symptomatic AS and LVEF ≥50% (defined as HF with preserved LVEF (HFpEF); n=15).

Results

MEE declined in tandem with reduced LVEF from HFpEF and HFmrEF to HFrEF (p=0.041, p<0.001, and p<0.001 versus control, respectively; Figure 1). Impaired MEE was aggravated with increasing LVM (p=0.001) due to a disproportionate increase in overall left ventricular MVO2. In a multivariate analysis, female sex (p<0.001), a lower body mass index (p<0.001), and advanced age (p=0.01) were associated with a lower MEE (Figure 2). HFpEF, HFmrEF, and HFrEF patients had distinct energetic profiles involving MEE, MVO2, MBF, ESWS, and LVM (Figure 2).

Conclusions

Mechanoenergetic uncoupling was evident in every clinical state within the HF syndrome and associated with left ventricular hypertrophy and progressive systolic dysfunction. Sex, age, and obesity impacted myocardial energetics. To date, the present study is the largest investigation of mechanoenergetic coupling across several categories of patients with heart failure. 11C-acetate PET extends our pathophysiological comprehension of the HF syndrome beyond LVEF.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Danish Heart FoundationThe Lundbeck Foundation Relationship between LVEF and MEEMyocardial energetics in heart failure
Left atrial strain evaluation and prognostic value in constrictive pericarditis patients undergoing pericardiectomy
Authors: Lo Presti S , Chan N , Saijo Y , Wang T , Klein A
Published: October 2021

Background

Left Atrial (LA) phasic volumes analyses is flawed with geometrical assumption requiring high endocardial border definition. LA strain analysis is an emergent technique that overcome some of these technical limitations. Prior studies of LA mechanics in pericardiectomy patients found improvement in LA strain at follow-up and manifested as symptomatic improvement, however their relationships with survival have not been investigated.

Purpose

We assessed LA strain before and after pericardiectomy and its association with all- cause mortality.

Methods

Consecutive patients with constrictive pericarditis who underwent pericardiectomy from 2000–2017 were retrospectively analyzed, analyzing pre-operative and post-operative (at 12 months) echocardiography. Exclusion criteria included atrial fibrillation, previous left sided valve surgery, concomitant valvular surgery at the index pericardiectomy, more than mild left sided valvulopathy and poor echocardiographic windows. Strain analyses was performed with Vector velocity imaging independent software. Univariate and multivariable analyses were utilized to identify factors associated with reduced survival.

Results

Amongst 190 patients included in the analyses, mean age was 58.5±12.7 years and 37 (19.5%) were female. The etiology of constriction was deemed idiopathic in 61.6% of the cases, median time interval surgery-postoperative echo was 67 days (IQR 6, 312 days). During median follow up of 3.3 years (IQR 0.73, 5.9 years) there were 37 deaths. After surgery, there was a significant decrease in LA reservoir, conduit and regional wall strains. (Table 1). Multivariable analysis demonstrated that postoperative 4C AL strain reservoir was independently associated with all-cause mortality (Table 2).

Conclusions

In pericardiectomy patients, postoperative 4C LA strain reservoir is independently associated with all-cause mortality. Perhaps, compensatory changes of septal and antero-posterior walls during constriction explain why after surgery these walls become less dynamic, negatively impacting the overall function. Overall, LA quantification and strains may become a useful clinical tool for risk stratification in pericardiectomy patients

Funding Acknowledgement

Type of funding sources: None. Table 1. Left atrial variables.Table 2. All-cause mortality predictors
Association between atrial high rate episode burden and autonomic and vascular function in patients with implanted cardiac device
Authors: Khan A A , Junejo R T , Thomas G N , Fisher J P , Lip G Y H
Published: October 2021

Background

Patients who experience frequent atrial high rate episodes (AHREs), recorded on implantable cardiac devices, are at an increased risk of stroke and systemic embolism. Increased duration of AHRE is related to higher risk of thromboembolic event. The underlying pathophysiology is unclear; however, autonomic and/or endothelial dysfunction may contribute.

Purpose

We tested the hypothesis that patients with high AHRE burden have worse autonomic and vascular function compared to patients with low AHRE burden.

Design

We studied 44 patients split in two groups: high AHRE burden (longest AHRE ≥24 hours; n=22) and low AHRE burden (longest AHRE <24 hours; n=22). Resting time- and frequency-domain measures of HRV were determined to index cardiac autonomic function. High-resolution ultrasound was used to measure brachial artery diameter at rest and during reactive hyperaemia (endothelium-dependent flow mediated dilation (FMD)).

Results

FMD was higher in the low AHRE burden group compared to high AHRE group (5.5% [95% confidence interval (CI):3.4–7.6] vs 3.1% [95% CI: 1.9–6.2]; p=0.04) (table 1). Mean heart rate (p<0.001) and AHRE burden (p=0.02) were independent predictors of FMD on multivariate analysis. Time-domain, frequency-domain and non-linear indices of HRV were not significantly different between the groups. A slower heart rate (Spearman's rho 0.369; p=0.01) and high AHRE burden (Spearman's rho −0.315; p=0.04) were independently associated with changes seen on FMD following adjustment for multiple variables (p=0.001 and p=0.03 respectively).

Conclusion

Endothelium-dependent FMD is impaired in patients with high AHRE burden, while HRV derived indices of autonomic function were not affected by AHRE burden. Endothelial dysfunction may play an important role in the adverse outcomes seen in patients who experience frequent AHRE.

Funding Acknowledgement

Type of funding sources: None.
Higher incidence of stroke in severe COVID-19 is not associated with a higher burden of arrhythmias: comparison to other types of severe pneumonia
Authors: Jirak P , Shomanova Z , Larbig R , Dankl D , Frank N , Seelmaier C , Butkiene D , Lichtenauer M , Strohmer B , Sackarnd J , Hoppe U , Sindermann J , Reinecke H , Pistulli R , Motloch L
Published: October 2021

Background

Thromboembolic events, including stroke, are typical complications of COVID-19. Whether arrhythmias, frequently described in severe COVID-19, are disease-specific and thus promote strokes is unclear. We investigated the occurrence of arrhythmias, and stroke during rhythm monitoring in critically ill COVID-19, compared to severe pneumonias of other origin.

Methods

Recruited were 120 critically ill patients requiring mechanical ventilation in three European tertiary hospitals, including n=60 COVID-19, matched according to risk factors for occurrence of arrhythmias to n=60 patients from a retrospective consecutive cohort of severe pneumonias of other origin.

Results

Arrhythmias, mainly atrial fibrillation (AF), were frequent in COVID-19. However, when compared to nonCOVID-19, no difference was observed with respect to ventricular tachycardias (VT) and relevant bradyarrhythmias (VT 10.0 vs. 8.4%, p=ns and asystole 5.0 vs. 3.3%, p=ns) with consequent similar rates of cardiopulmonary resuscitation (6.7 vs. 10.0% p=ns). AF was even more common in nonCOVID-19 (AF 18.3 vs. 43.3%, p=0.003; newly onset AF 10.0 vs. 30.0%, p=0.006) which resulted in higher need for electrical cardioversion (6.7 vs. 20.0%, p=0.029). Despite these findings and comparable rates of therapeutic anticoagulation (TAC), the incidence of stroke was higher in COVID-19 (6.7.% vs. 0.0, p=0.042). These events happened also in absence of AF (50%) and with TAC (50%).

Conclusion

Arrhythmias were common in severe COVID-19, consisting mainly of AF, yet less frequent than in matched pneumonias of other origin. A contrasting higher incidence of stroke independent of arrhythmias observed also with TAC, seems to be an arrhythmia-unrelated disease-specific feature of COVID-19.

Funding Acknowledgement

Type of funding sources: None. Figure 1
Comparative effectiveness and safety of edoxaban vs warfarin in patients with atrial fibrillation: a nationwide cohort study
Authors: Nielsen P B , Soegaard M , Jensen M , Ording A G , Lip G Y H
Published: October 2021

Background and purpose

The effectiveness and safety of edoxaban 60 mg and 30 mg for stroke prevention compared with warfarin in patients with atrial fibrillation (AF) has not been well-described in a nationwide cohort of Caucasian patients treated in standard clinical practice.

Methods

We used Danish nationwide registries to identify patients with AF during June 2016 and November 2018 who were treated with edoxaban or warfarin and computed rates per 100 person-years of thromboembolic, all-cause mortality, and bleeding events using an inverse probability of treatment weighting approach to account for baseline confounding. We used weighted pooled logistic regression to compute hazard ratios (HRs) with 95% confidence intervals (CIs) comparing events between edoxaban 60 mg and warfarin users; edoxaban 30 mg was not included in formal comparisons.

Results

We identified 6451 AF patients, mean age was 72 years and 40% were females. A total of 1772 patients were treated with edoxaban 60 mg, 537 with edoxaban 30 mg, and 4142 with warfarin. The median CHA2DS2-VASc score was similar between warfarin and edoxaban 60 mg with a score of 3 (interquartile range [IQR] 2–4). In the inverse probability of treatment-weighted pseudo-population, the thromboembolic event rate for edoxaban 60 mg was 0.95 and 1.0 for warfarin, corresponding weighted HR of 1.00 (95% confidence intervals [CI] 0.59, 1.71); see Figure. Edoxaban 60 mg users were associated with lower rates of all-cause mortality (3.93) compared to warfarin (6.04), with a HR of 0.64 (95% CI 0.47 to 0.88). The event rates for bleeding were 3.36 and 3.14, respectively; HR 1.09 (95% CI 0.77, 1.57)

Conclusion

Edoxaban 60 mg is a safe and effective treatment compared with warfarin for stroke prevention in routine clinical care for white European patients with AF, with non-significantly different risks for stroke and clinically relevant bleeding, but lower all-cause mortality.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work was supported by an unrestricted research grant from Daiichi-Sankyo Europe GmbH. This funding source had no role in the design of this study, its execution, analyses, interpretation of the data, or decision to submit results.
Speckle tracking-derived left atrial stiffness predicts adverse events after successful electrical cardioversion
Authors: Kupczynska K , Miskowiec D , Michalski B , Kasprzak J D
Published: October 2021

Background

Atrial fibrillation (AF) impairs cardiac mechanics and leads to adverse remodelling. Increased left atrial (LA) stiffness reflecting LA reservoir function and left ventricular (LV) filling pressure is one of the symptoms of LA remodelling.

Purpose

To analyse LA stiffness within 24 hours after successful electrical cardioversion and its prognostic value during 2-years follow-up.

Methods

Prospective study involved 71 patients with nonvalvular AF (mean age 64±13 years, 61% male). All patients underwent echo during 24 hours after conversion to sinus rhythm. We analysed standard echocardiographic and Doppler parameters. Using speckle-tracking method we assessed peak LA longitudinal strain in 4- and 2-chamber view. LA stiffness was calculated as the quotient of peak LA longitudinal strain (LA reservoir function) and mean E/E' ratio. The clinical endpoints were predefined as AF recurrence and cardiovascular hospitalization.

Results

Median time of current AF episode was 2 (IQR 0.4–5) months. Standard echo measurements revealed median of LV ejection fraction 55% (IQR 45–58) and median of LA volume indexed to body surface area 42 ml/m2 (IQR 34–51). During follow-up we noticed AF recurrence in 48 (68%) patients and cardiovascular hospitalization in 43 (61%) patients. Median time-to-event was 2.4 (IQR 1 to 6.9) and 7 (IQR 2.1–11) months, respectively. Receiver operating characteristic curve analysis revealed that LA stiffness >0.53 (AUC=0.821; p<0.0001) and >0.95 (AUC=0.788; p<0.0001) were the optimal cut-off values for predicting AF recurrence and cardiovascular hospitalization. Figure presents Kaplan-Meier survival analysis for AF recurrence (A) and for hospitalization (B). Moreover LA stiffness remain statistically significant in multivariate Cox regression analysis even after adjustment for betablockers, antiarrhythmic drugs, coronary artery disease, heart failure and mitral regurgitation. Relative risk was 1.51 (95% CI 1.09–2.09), p=0.01 for AF recurrence and 1.49 (95% CI 1.05–2.13) for cardiovascular hospitalization.

Conclusions

Speckle tracking-derived LA stiffness assessed early after the restoration of sinus rhythm independently predicts AF recurrence and cardiovascular hospitalization.

Funding Acknowledgement

Type of funding sources: None.
Characteristics and long-term ablation outcomes of supraventricular arrhythmias in hypertrophic cardiomyopathy: a 10-year, single-center experience
Authors: Zhang H D , Ding L , Weng S X , Zhou B , Ding X T , Hu L X , Qi Y J , Yu F Y , Feng T J , Zhang J T , Fang P F , Zhang S , Tang M
Published: October 2021

Background

A variety of supraventricular arrhythmias (SVAs) may occur in patients with hypertrophic cardiomyopathy (HCM). The characteristics and long-term ablation outcomes of different types of SVAs in HCM have not been comprehensively investigated.

Methods

We retrospectively enrolled 101 consecutive symptomatic HCM patients with suspected arrhythmia from May 2010 to October 2020. The clinical features and ablation outcomes of patients with SVAs were further analyzed.

Results

Seventy-eight patients had SVAs, consisting of 50 (64.1%) atrial fibrillation (AF), 16 (20.5%) atrial flutter (AFL), 15 (19.2%) atrioventricular reentrant tachycardia (AVRT), 11 (14.1%) atrial arrhythmia (AT), and 3 (3.8%) atrioventricular nodal reentrant tachycardia (AVNRT). Thirty-four patients underwent catheter ablation including 14 for AF, 9 for AVRT, 6 for AFL, 3 for AVNRT, 1 for both AF and AFL, and 1 for both AF and AVRT. They were followed up for a median (interquartile range) of 58.5 (82.9) months. There were no recurrences for patients with non-AF SVAs. For patients with AF, the 1- and 7-year AF-free survival were 87.5% and 49.5%, respectively. A ROC analysis revealed that a greater left ventricular end-diastolic dimension (LVEDD) was associated with higher recurrence of AF with an optimum cutoff value of 47mm (c-statistic = 0.91, p=0.011, sensitivity = 1.00, specificity = 0.82). In Kaplan-Meier analysis, patients with LVEDD ≥47mm had worse AF-free survival (log-rank p=0.014).

Conclusions

AF is the most common SVA in HCM, with AFL, AVRT, AT, and AVNRT ranking the second to the last according to the prevalence. The long-term catheter ablation outcome for non-AF SVAs in HCM is satisfying. A greater LVEDD predicts AF recurrence after catheter ablation in patients with HCM.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): National Natural Science Foundation of China Figure 1Figure 2
Long-term outcomes of 265,737 patients hospitalised with atrial fibrillation and atrial flutter from 2008 to 2015
Authors: Ngo L , Woodman R , Walters T , Denman R , Yang I , Ranasinghe I
Published: October 2021

Background

Atrial fibrillation/atrial flutter (AF/AFL) hospitalisations are common, however, little is known about the long-term outcomes of these episodes.

Objective

To examine the incidence of mortality, all-cause and cause-specific re-hospitalisations at up to 8 years after a hospitalisation for AF/AFL.

Methods

Unique patients hospitalised with a primary diagnosis of AF/AFL from 2008–2015 were identified using nation-wide hospitalisation data from Australia and New Zealand. All-cause mortality was the primary outcome. Secondary endpoints included all-cause and cause-specific re-hospitalisations. Results were reported as incident rate per 100 patient-years.

Results

We included 265,737 patients (mean age 69.9±13.9y, female 45.2%, elective 28.7%). The median length of stay was 1 day (Interquartile range [IQR] 0–4 days) and the median CHA2DS2-VASc score was 2 (IQR 1–2). During the index hospitalisation, 9,837 (3.7%) patients underwent catheter or surgical ablation and 52,634 (19.8%) underwent cardioversion. During the median follow-up time of 3.4 years (range 0–8.0 years), 53,669 patients died (incident rate of 5.7/100 patient-years) with a survival probability gradually decreasing from 92.8% (95% CI 92.7–92.9%) at 1-year to 65.4% (95% CI 64.9–65.8%) at 8-years post-discharge (Table 1 and Figure 1). All-cause re-hospitalisations occurred in 210,118 patients (incident rate of 22.2/100 patient-years) with a rehospitalisation-free survival probability of 7.1% (95% CI 6.9—7.3%) at the end of follow-up. Unplanned re-hospitalisations occurred more frequently than planned episodes (incident rate of 17.2 vs. 16.6/100 patient-years respectively). AF/AFL accounted for 25.1% of all-cause re-hospitalisations (incident rate of 8.9/100 patient-years) and the probability of freedom from re-hospitalisations for AF/AFL was 55.4% (95% CI 55.0–55.8%) at 8-years. Incident rates of re-hospitalisations for catheter ablation (1.5/100 patient-years), stroke (1.6/100 patient-years), heart failure (2.7/100 patient-years), and acute myocardial infarction (1.0/100 patient-years) were low. In subgroup analyses, worse survival was observed in female patients, older age groups, patients with comorbid heart failure, hypertension, diabetes, and those who did not undergo ablation during the index hospitalisation.

Conclusion

Nearly two-thirds of patients were surviving by 8-years following an AF/AFL hospitalisation with a low rate of re-hospitalisations for stroke, heart failure, and myocardial infarction. However, re-hospitalisations for recurrent atrial arrhythmia were common. Efforts to reduce re-hospitalisations, especially unplanned encounters, are required to improve patient outcomes.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): National Heart Foundation of Australia
Activity levels influence frequency of premature atrial contractions
Authors: Johnson L S B , Napiorkowski N , Grotek A , Dziubinski M , Healey J S , Engstrom G
Published: October 2021

Background

Frequent premature atrial contractions (PACs) are associated with substantially increased risk of atrial fibrillation (AF) and stroke, but PAC count varies substantially day-to-day. With the emergence of potential therapies for primary prevention of AF reliable estimation of PAC frequency is increasingly relevant, as is an understanding of PAC determinants.

Purpose

To determine the effect of daily activity and heart rate on an individuals' daily PAC count.

Methods

We included a random sample of patients 18–85 years without AF who recorded an ambulatory ECG for 7–31 days in the U.S.A during 2019 using a full-disclosure mobile cardiac telemetry device, and who had ≥500PACs on at least one recording day. PACs were algorithmically detected and manually verified. PAC count and activity was sampled for each individual and each recording day during daytime (06–22h). The effect of activity on daily PAC count was assessed in a negative binomial regression model including age, sex and with a random effect for individual, to account for confounding due to inter-individual differences.

Results

The study population consisted of 2,094 patients, of which 48% were men (Fig 1). Mean time spent in activity was 32% (standard deviation (SD 10%) for men and women 31% (SD 10%) for women (Fig 2). The median PAC count was 592 (inter-quartile range 1280). Beyond age, sex and intra-individual differences PAC frequency was determined by activity levels, (intercept 629 PACs; incidence rate ratio per 10 minute increase in activity 1.03, p<0.0001). A 1-hour increase in daily activity was associated with a 20% increase in daily PACs count.

Conclusions

Physical activity is associated with increased PACs counts, implying both that a reliable diagnosis of PAC frequency needs to be conducted during a person's habitual level of activity and that PAC frequency is modifiable. In-hospital assessments of PACs while patients are mainly inactive may underestimate PAC frequency.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): the Swedish Society For Medical Researchthe Swedish Heart and Lung Foundation Age and sex distributionActivity levels by sex
Arrhythmia patterns in patients with COVID-19 infection during and post hospitalization detected via a patch-based mobile cardiac telemetry system
Authors: Reynbakh O , Braunstein E D , Hsu M , Ellis J , Crosson L , Lenane J , Krumerman A , Di Biase L , Ferrick K J
Published: October 2021

Background

Coronavirus infection (COVID-19) is the cause of the current world-wide pandemic. Cardiovascular complications occur in 20–30% of patients with COVID-19 infection including myocardial injury and arrhythmias. Current understanding of specific arrhythmia type and frequency is limited. In response to COVID-19 pandemic and overwhelmed hospital critical care and telemetry recourses, patch-based cardiac monitoring system received emergency Food and Drug Administration (FDA) approval for inpatient monitoring. A patch-based cardiac telemetry system has been shown to be useful for patient management during the COVID-19 pandemic and provides detailed analysis of cardiac rhythms.

Purpose

To analyze arrhythmia type and frequency in patients with COVID-19 infection, identifying arrhythmia patterns over time during hospitalization and after discharge.

Methods

A prospective cohort study during the COVID-19 pandemic was performed. We included patients hospitalized with COVID-19 infection who had a patch-based mobile telemetry device placed for cardiac monitoring. A quantitative analysis including type, frequency and duration of detected arrhythmias was performed at the end of the monitoring period.

Results

A total of 103 patients hospitalized with COVID-19 diagnosis underwent monitoring. Quantitative reports for 59 patients were available for analysis, among those 59% were males, median age 65 (IQR 56–76) yrs. Mean wear time was 6.8±5.0 days. Arrhythmias were detected in 72.9% of patients. Majority of arrhythmias were SVT (59.3% of patients) and AF (22.0%). Episodes of AF duration >30 min were detected in 12 patients. New onset AF was noted in 15.0% of patients and was significantly associated with age (OR 1.4 for 5 yrs difference; 95% CI 1.01–2.05). Brady arrhythmias (2nd degree, 3rd degree AV bock, pause≥3 seconds) were seen in 18.7% of patients. Arrhythmias were consistently detected throughout the monitoring period in 52.9%-89.5% of patients daily (Figure 1). In 9 patients who were discharged with continued patch monitoring, 3 patients (33.3%) had arrhythmic events during their outpatient monitoring period.

Conclusion

A majority of patients hospitalized with COVID-19 infection had arrhythmias detected by patch cardiac monitor. Arrhythmias were observed throughout hospitalization with a consistent daily frequency. Patients continued to exhibit cardiac arrhythmias after hospital discharge of a type similar to that seen during hospitalization. New onset AF often occurred and was associated with older age. Inpatient application of a patch cardiac telemetry with continued monitoring as outpatient is feasible and effective in detecting occult arrhythmias in patients with COVID-19 infection.

Funding Acknowledgement

Type of funding sources: None. Daily frequency of arrhythmias detected