Global Index Research Articles

Generating high-quality phase-only holograms of binary images using global loss and stochastic homogenization training strategy

Deep learning presents a highly effective for computer-generated holography (CGH). However, existing learning-based CGH algorithms may encounter significant obstacles in generating high-quality holograms for binary images. This study proposes a novel diffraction model-driven neural network, termed load sharing yielding holography (LSY-Holo), which leverages a dual-branch architecture and a global structural similarity index measure (Global_SSIM) loss function to generate phase-only holograms (POHs). LSY-Holo framework facilitates capturing global information, enhancing the network’s performance to address the ill-posed inverse problem. To further optimize the model for binary images, the research introduces a custom Binary dataset alongside a stochastic homogenization preprocessing method (SHPM), which mitigates the prevalent issue of excessive noise in reconstructed images. Additionally, this deep learning approach is integrated with an iterative algorithm, which employs holograms rapidly generated by LSY-Holo as the initial phase of the AdamW Holography (AH) algorithm. This strategy significantly accelerates the convergence of the iterative process. LSY-Holo is further extended to 3D scenes, enabling dynamic defocusing and focusing effects at varying depths. Results from numerical simulations and full-color optical reconstruction experiments demonstrate that the proposed method can enhance image quality and effectively reduce the artifacts in reconstructed images.

Relationship between antioxidant activity and ESIPT process based on flavonoid derivatives: A comprehensive analysis

Antioxidant activity, as a topic of current interest, is discussed together with the excited state intramolecular proton transfer (ESIPT) process for three flavonoid derivatives, based on density functional theory (DFT)and time-dependent DFT (TD-DFT) methods, as well as DPPH free radical scavenging assay. The potential energy curves and transition states demonstrate that the three molecules can undergo only single proton transfer in the excited state, and all of them are ultrafast ESIPT processes. The absorption spectra of all the molecules show effective protection against UV radiation with low fluorescence intensity, especially Baicalein (Bai), which demonstrates their great potential for sunscreen applications. The density of states, HOMO energy values, global and local indices reveal that the antioxidant activity of the molecules after ESIPT process is enhanced, with Bai having the highest antioxidant activity, which is significantly attributed to the number and position of phenolic hydroxyl groups. Moreover, by comparing the DPPH free radical scavenging activity under the dark and UV radiation conditions, the radical scavenging activity (RSA) value in the UV radiation is remarkably higher than that in the dark condition, in which Bai achieves RSA value of 93.4%. Overall, the antioxidant activity of all three ESIPT-based flavonoid derivatives, especially Bai, is significantly elevated in the keto* form, which reinforces the significant relationship between antioxidant activity and ESIPT process, and provides new application prospects for molecules with ESIPT properties.

The COVID-19 Pandemic and Feedback Trading Dynamics: Unveiling Global Patterns

This study analyzes how the COVID-19 pandemic impacted stock markets worldwide using the COVID-19 Global Fear Index (GFI) devised by Salisu and Akanni (2020). We examine feedback trading behaviors in stock indices across 70 countries, revealing a complex relationship between pandemic-sentiment and feedback trading. Our study finds that GFI primarily motivates negative feedback trading in many developed countries, particularly those in higher latitudes, while the relationship between pandemic-sentiment and feedback trading is complex and varies across regions. Notably, China and India deviate from these patterns, exhibiting no significant feedback trading effects. These results highlight how regional differences shape financial market responses to the COVID-19 crisis. This analysis offers valuable insights into the pandemic's nuanced impact on global financial markets, emphasizing the distinct reactions across diverse geographic regions.

A novel method measuring the clustering of particles: Pseudo-gravitation

A novel pseudo-gravitation method is proposed to quantitatively measure the degree of the preferential concentration of particles in turbulent flows, where virtual gravitations are employed to evaluate the extent of particle accumulation. The pseudo-gravitation method introduces a nondimensional “Gravitation Index” (GĨ) to estimate the local concentration of particles and a nondimensional “Global Gravitation Index” (GGĨ) to quantify the degree of particle clustering across the whole domain. This method can effectively characterize both the Eulerian and Lagrangian properties of the particle preferential concentration, without the need for any predefined artificial parameters. Additionally, it is not only robust to the variation in the number of particles but also sensitive to the change in physical parameters, such as the Stokes number (St) and Reynolds number (Re).

Measuring carbon emission performance in China's energy market: Evidence from improved non-radial directional distance function data envelopment analysis

The most complex challenge facing the energy market is identifying effective solutions to reduce CO2 emissions (CEs) and enhance environmental performance (EP). Coal production within the power sector is the primary source of these emissions. In this study, we developed a novel linear programming model that accounts for undesirable outputs to assess the EP of 15 power enterprises in eastern China from 2016 to 2020. In addition, we employed a global non-radial Malmquist-Luenberger productivity index (GNML) to analyse the mechanisms influencing changes in efficiency among these enterprises. Our findings indicate that, while the EP of the power industry in eastern China improved, it remains at a relatively low level and exhibits instability. Moreover, technological efficiency (TE) and scale efficiency (SE) play a significant role in determining production efficiency within the sector. Therefore, it is essential for industry managers to implement standardized production management regulations, enhance technological development and scale investments, and strengthen control over unintended emissions that could facilitate energy transition.

Yellow fever breakthrough infections after yellow fever vaccination: a systematic review and meta-analysis

Yellow fever vaccination is considered to provide effective long-term immunity. However, yellow fever breakthrough infections in vaccinated patients have been reported. In this systematic review and meta-analysis we aimed to identify and summarise all documented symptomatic yellow fever breakthrough infections in the literature occurring less than 10years and 10years or more after primary yellow fever vaccination. We searched MEDLINE (Ovid), Embase (Ovid), and Global Index Medicus for records published between Jan1, 1936 (introduction of yellow fever vaccination) and June 16, 2023. We included prospective and retrospective cohort studies, case series and reports, and epidemiological reports from national and international health organisations reporting symptomatic yellow fever among individuals vaccinated 30days or more before symptom onset. Weexcluded cases vaccinated less than 30days before symptom onset. The primary outcome for the meta-analysis was the proportions of vaccinees among virologically confirmed and probable cases of yellow fever (IgMseroconversion without seroconversion to other flaviviruses). Risk of bias was assessed with an adapted version of the Newcastle-Ottawa Scale. Records of moderate or good quality (probable or confirmed yellow fever diagnosis with documented proof of previous vaccination) were included for random-effects meta-analysis. Thissystematic review and meta-analysis is registered with PROSPERO, number CRD42023450205. After reviewing 1975records, 37records reported a total of 6951yellow fever cases, of which 537were vaccinated. 31records were of low quality. Nine confirmed and 24probable cases with proof of previous yellow fever vaccination were identified, all from Brazil. Confirmed cases were vaccinated 3months to 3years before symptom onset; of these patients two fell severely ill and died. The pooled proportion of verified yellow fever breakthrough infections among probable and confirmed cases was 3% (95% CI 1-19%). No confirmed yellow fever breakthrough infections were identified occurring 10years or more after yellow fever vaccination. Yellow fever breakthrough infections documented in literature are rare, and not necessarily more common 10years or more after primary yellow fever vaccination. This finding suggests that a single dose of yellow fever vaccination is sufficient to provide lifelong protective immunity against symptomatic yellow fever. None.

The Impact of Russia – Ukraine War on Global Economy

The invasion of Ukraine by Russia contributed to a notable rise in global prices of food and crude oil petroleum. The surge in the global food price index following the invasion was fueled by supply chain disruptions. In general, the incursion resulted in a continuous increase in inflation in both belligerent and non-belligerent nations. The following study shows how economic sanctions and regional conflict lead to an international energy crisis. Despite mediating countries like Turkey, it had a disastrous impact not only on geopolitical stability but also on economic development within and outside of Europe. The study used to assess the impact of Russia's invasion of Ukraine on global trade and business. This paper investigates the global economic growth and consequences of the Russia-Ukraine war over a four month period from December 2021 to March 2022. Russia invaded Ukraine on the 24th of February 2022.

Interconnected Stock Markets: Analysing Cointegration and Correlation among Global Stock Indices

This study examines the long-term and short-term relationships among five major global stock indices—NSE NIFTY (India), S&P 500 (USA), FTSE 100 (UK), Hang Seng (Hong Kong), and Nikkei 225 (Japan)—over the period from 2008 to 2023. Using advanced econometric techniques such as Johansen cointegration tests, Engle-Granger residual cointegration test and the Vector Error Correction Model (VECM), the research explores the degree of interconnectedness and cointegration among these indices. The results indicate strong positive correlations between NSE NIFTY, S&P 500, and Nikkei 225, suggesting a growing synchronization of these markets due to global economic integration. Johansen's test reveals the presence of multiple long-term equilibrium relationships, affirming that despite short-term deviations, these markets tend to move together in response to global macroeconomic factors. The analysis further highlights that the S&P 500 and FTSE 100 indices exhibit significant error correction mechanisms, underscoring their leadership role in global market dynamics. In contrast, NSE NIFTY shows a weaker adjustment toward long-term equilibrium, indicating its reactive nature to changes in other global indices, particularly the S&P 500. The study finds that while Hang Seng and Nikkei 225 are connected globally, their short-term linkages appear weaker, likely influenced by regional factors. Overall, the results emphasize the critical influence of the U.S. and Japanese markets on NSE NIFTY, with both long-term cointegration and short-term market dynamics shaping the Indian stock market’s movements. This research offers key insights for investors seeking to understand global stock market interdependencies and manage portfolio risk.

An anthropomorphic phantom for atrial transseptal puncture simulation training

BackgroundTransseptal puncture (TSP) is a critical prerequisite for left-sided cardiac interventions, such as atrial fibrillation (AF) ablation and left atrial appendage closure. Despite its routine nature, TSP can be technically demanding and carries a risk of complications. This study presents a novel, patient-specific, anthropomorphic phantom for TSP simulation training that can be used with X-ray fluoroscopy and ultrasound imaging.MethodsThe TSP phantom was developed using additive manufacturing techniques and features a replaceable fossa ovalis (FO) component to allow for multiple punctures without replacing the entire model. Four cardiologists and one cardiology trainee performed TSP on the simulator, and their performance was assessed using four metrics: global isotropy index, distance from the centroid, time taken to perform TSP, and a set of 5-point Likert scale questions to evaluate the clinicians’ perception of the phantom’s realism and utility.ResultsThe results demonstrate the simulator’s potential as a training tool for interventional cardiology, providing a realistic and controllable environment for clinicians to refine their TSP skills. Experienced cardiologists tended to cluster their puncture points closer to regions of the FO associated with higher global isotropy index scores, indicating a relationship between experience and optimal puncture localization. The questionnaire analysis revealed that participants generally agreed on the phantom’s realistic anatomical representation and ability to accurately visualize the TSP site under fluoroscopic guidance.ConclusionsThe TSP simulator can be incorporated into training programs, offering trainees the opportunity to improve tool handling, spatial coordination, and manual dexterity prior to performing the procedure on patients. Further studies with larger sample sizes and longitudinal assessments are needed to establish the simulator’s impact on TSP performance and patient outcomes.

Climate change and vegetation greening jointly drive the spatial pattern of net radiation variability in northern China

ABSTRACT The spatial and temporal variations of net surface radiation (Rn) are critical for comprehending ecological environments. Nonetheless, the intricate interplay among Rn dynamics, vegetation growth, climate, and natural factors remains inadequately elucidated. In this study, we estimated net surface radiation based on Landsat data and ERA5 meteorological data in the Google Earth Engine (GEE) platform, which closely matched the observable spatial distribution (R 2 = 0.96), with an average growth rate of 0.15 MJ m−2 mth−1. Trend analyses and spatial autocorrelation were used to explore the spatial and temporal changes in net radiation from 2000 to 2020, the global Moran's index for net radiation was found to exceed 0.76, with fluctuating increases, showing a highly positive spatial distribution of Rn. Local Moran's I predominantly fell into two categories: ‘High-High’ and ‘Low-Low’, with the first increasing in range and the latter decreasing. Combining GeoDetector and PLS-SEM analyses, temperature and vegetation emerge as predominant drivers of net surface radiation variation within the study area, each contributing more than 17% to Rn change. Furthermore, interactions between any two factors typically exhibits nonlinear enhancement. PLS-SEM underscores the influence of vegetation and climate on Rn, with other factors indirectly affecting net radiation changes by influencing vegetation growth.

Comparative Study of Docking Tools for Evaluation of Potential Copper Metallodrugs and Their Interaction with TMPRSS2

COVID-19 has caused over seven million deaths globally due to its high transmission rate. The virus responsible for the disease requires a transmembrane protease serine type II (TMPRSS2-7MEQ) to infiltrate host cells and has been linked to several cancers, particularly prostate cancer. To investigate COVID-19 potential therapies, a series of Casiopeina-like copper complexes containing 1,10-Phenanthroline and amino acids were investigated as TMPRSS2 inhibitors. The molecular structures of twelve Phenanthroline copper complexes were calculated, and their global reactivity indices were analyzed using DFT and conceptual DFT methods. Three molecular docking algorithms were employed to identify the most effective inhibitors by examining their interactions with amino acid residues in the target protein’s catalytic activity triad (Asp345, His296, and Ser441). All complexes are docked above the catalytic site, blocking the interaction with substrates. The Phenanthroline complexes showed better interactions than the Bipyridine complexes, likely due to increased hydrophobic contacts. Analogs’ cationic nature and amino acids’ basic side chains bring them near the active site by interacting with Asp435. The top complexes in this study contain Ornithine, Lysine, and Arginine, making them promising alternatives for researching new drugs for COVID-19 and cancers like prostate cancer.

Innovation and infrastructure: driving forces for entrepreneurship development and economic opportunities

Purpose. To determine the relationship between innovation and infrastructure to support entrepreneurship as factors of growth of economic opportunities, based on the results of empirical research. Methodology. The case method and modern tools of econometric research were used to create an economic-mathematical model that assesses the relationship between economic opportunities and indicators of economic innovation. The research is based on the results of the Gallup 75 Years Anniversary Survey on current and future economic opportunities, as well as Global Innovation Index (GII) indicators. Findings. Creating favorable conditions for doing business and developing entrepreneurship is critically important for the economic recovery of Ukraine. The high level of entrepreneurial activity among Ukrainians emphasizes the importance of the development of innovative infrastructure and business support. The developed models can be used to forecast the economic capabilities of the population, which will contribute to the return of citizens and the development of the national economy. Thus, innovations and an effective infrastructure to support entrepreneurship play a key role in ensuring sustainable economic growth and social well-being in Ukraine. The results of the study can become the basis for developing strategies for economic development and solving migration problems in the post-war period. Determinants of the growth of economic opportunities of the population (human capital) are determined. The suggested GII parameters most correlate to positive feedback on economic opportunities and growth over the next 25 years. Originality. For the first time, the relationship between economic opportunities, the development of innovations and the development of infrastructure at the enterprise has been empirically proven. Statistically significant predictors of current and future economic opportunities of the population are substantiated and relevant economic and mathematical models for their evaluation and forecasting are developed. Practical value. The results of the study are particularly relevant in the context of solving the migration crisis caused by Russia’s military aggression against Ukraine. The return of citizens who have left the country depends on the creation of favorable conditions for business and the development of entrepreneurship. The developed models can be used to forecast the economic opportunities of the population in different countries, which will allow effective management of migration processes and promote the development of national economies. This will ensure the creation of a favorable business environment, which is critical for sustainable economic growth and social well-being.

DETERMINANTS OF FOOD SECURITY AMONG INDONESIAN FARMING HOUSEHOLDS

The Global Food Security Index (GFSI) shows an increase in Indonesia's food security from 2021 to 2022. However, this increase does not yet indicate better Indonesian food security because this increase is still lower than the global average and the Asia Pacific average. The food security conditions of farming households could be a solution considering the importance of farming household food security which can deliver an impact in maintaining economic stability and reducing dependence on the market. This research aims to analyze the factors that influence the food security of farming households. The model used is Robust Regression since the Normality and Heteroscedasticity assumptions were failed. Data were taken from IFLS wave 5. Based on the results, it shows that the variables of age, gender, home ownership status, cooking fuels, electricity use and house location influence the food security of farming households. While, the variables of head of household’s education, availability of toilets and water sources have no effect on the food security of farming households

Spatiotemporal variations of global precipitation concentration and potential links to flood-drought events in past 70 years

The evaluation of precipitation events is crucial for predicting severe droughts and floods, particularly in the context of global warming. This study presents a comprehensive spatiotemporal analysis of the global precipitation concentration index (CI) from 1950 to 2020, comparing CI with nine extreme precipitation indices to assess its applicability. The world map was divided into three distinct regions related to flood-drought events using the standardized precipitation index (SPI). Key findings include: 1) CI exhibited significant spatial heterogeneity, with elevated values in seasonally warm coastlines and arid regions. Seasonal changes in CI were not synchronized, particularly lower in Northern Hemisphere winters, while the Southern Hemisphere displayed minor seasonal variation, alongside a long-term growth trend in approximately 36.5 % of the global area. 2) CI's spatiotemporal variations helped delineating regional precipitation patterns, revealing a strong correlation (R2 = 0.87) with the extreme precipitation index R95c, but a negligible relationship with total precipitation (P) (R2 = −0.05). This facilitated the global partitioning into three regions: Humidity Amplification Region (I), Dryness Intensification Region (II), and Climate Fluctuation Region (III). 3) Flood-drought events were potentially linked to variations in CI and P, where In Region I experienced increased flood risk due to rising CI and P, Region II faced heightened drought risk from rising CI and declining P, and Region III showed opposing effects on floods due to reduced CI and increased P, with P variability significantly influencing flood frequency. 4) The main atmospheric circulation factors varied by region, typically including the Antarctic Oscillation (AAO), Atlantic Multi-decadal Oscillation (AMO) and Arctic Oscillation (AO), with AAO being most significant. This research underscores the intricate relationships between climatic indices and hydrological extremes, emphasizing the challenges posed by global warming, atmospheric circulation changes, and data uncertainties in assessing drought and flood disasters.

Academic libraries readiness in the Fourth Industrial Revolution: a comparative study between Ghana and South Africa

PurposeThis study compares the Fourth Industrial Revolution (4IR) preparedness of two advanced academic libraries each in Ghana and South Africa.Design/methodology/approachThe study utilized a conceptual framework that emanated from the Socio-Technical Theory (STT) and Global Competitiveness Index (GCI) models. Employing convergent parallel mixed methods, including questionnaires and interviews, 167 respondents, comprising librarians, IT staff and directors, shared insights on challenges faced by academic libraries in adapting to 4IR.FindingsFindings highlight a deficiency in Lib 4.0 skills crucial for survival in the 4IR, with South Africa showing better readiness. Both countries lack Lib 4.0 policies and face budget constraints, inadequate ICT infrastructure and limited support. The findings underscore the impact of relevant training on staff embracing Lib 4.0 technologies.Originality/valueThe study then proposes a comprehensive model, highlighting the significance of librarians adopting a growth mindset and priori V Btizing continuous learning, relearning, reskilling and upskilling to effectively navigate the complexities posed by the 4IR.

Differences in myocardial work across functional class strata in a severe aortic stenosis AHA D1 population. A cross-sectional study

Abstract Background Aortic stenosis is the most prevalent degenerative valvopathy. [1,2] The contractile state of the left ventricle has prognostic value in these patients. Global longitudinal strain (GLS) is the most accurate method for the estimation of myocardial performance. However, its value depends on the left ventricular afterload, [3,4] making GLS values challenging to interpret for decision-making purposes. The global myocardial work index (GWI) is an innovative echocardiographic technique for assessing myocardial function.[5] From these values, other indices representing constructive work, wasted work, and myocardial efficiency can be calculated.[6] Purpose The objective of our study was to measure the GWI and its derivatives using transthoracic echocardiography and relate them to the patient's functional class. Methods We conducted an observational, cross-sectional, and analytical study, including patients with severe aortic stenosis AHA D1, aged over 45 years, hypertensive, without coronary lesions. We exclude patients with other associated valvulopathies and rhythm disorders. All patients underwent transthoracic echocardiography, with measurements of GLS and GWI. Systolic blood pressure was added to the mean gradient of the aortic valve obtained by continuous Doppler. The population was divided into those with NYHA functional classes I/II and those with NYHA III/IV. Results Between May 2022 and August 2023, we included 152 patients, average age was 68 +/- 9 years. Of these, 54% were male, 38% had type 2 diabetes, 36% had dyslipidemia, and 30% had a history of smoking. Regarding functional class, 21% were in NYHA class I, 37% in NYHA II, 32% in NYHA III, and 9% in NYHA IV. The mean LVEF of 60 +/- 5%, GLS strain of -15.1 +/- 3.1; mean GWI was 2251 +/- 595 mmHg%, while the global constructive work index was 2526 +/- 596 mmHg%. The median wasted work index was 198.2 (196-204.2) mmHg%, and the mean myocardial efficiency was 89.9 +/- 4.7%. The global myocardial work index was 2455 +/- 582 in patients with NYHA I/II vs 1978 +/- 527 mmHg% in patients with NYHA III/IV (p<0.001) (Table 1). For the global constructive work, patients in NYHA I/II had a mean of 2708 +/- 590 mmHg, while those in NYHA III/IV had 2281 +/- 542 mmHg% (p<0.001). There were no significant differences in wasted work (190 +/- 11 mmHg%, NYHA I/II vs 210 +/- 113 mmHg%, NYHA III/IV, p=0.27). Marginally statistically significant difference was observed for myocardial efficiency (91 +/- 4.8%, NYHA I/II vs 89 +/- 4.5%, NYHA III/IV, p=0.49). Conclusions Patients with severe aortic stenosis have supranormal myocardial work indices.[7] However, as the disease progresses and patients experience greater clinical deterioration, these indices decrease, showing a significant difference between functional classes I/II and III/IV. Further studies are needed to determine the utility of these indices as prognostic indicators in this patient group.Table 1.Differences in myocardial workBulley

Preserved left ventricular ejection fraction with abnormal myocardial work in sepsis

Abstract Background Sepsis is a life-threatening condition associated with a dysregulated response to infection, leading to an increased risk of multi-organ dysfunction and death. Left ventricular (LV) dysfunction has been reported in up to 60% of patients with sepsis. Still, it’s true incidence is difficult to determine as defined by standard methods like left ventricular ejection fraction (LVEF) due to its dependency on loading conditions. Myocardial work (MW) is a validated novel parameter informing true LV contractility. MW is calculated using echocardiography strain data, noninvasive BP measurements, and GE Healthcare proprietary software. There are four MW indices; here, we evaluated the global work index (GWI), the indexed total work performed by the LV through mechanical systole, including isovolumic relaxation and contraction. Purpose To describe our patient population diagnosed with sepsis with GWI calculated as part of their echocardiography. We also sought to compare the GWI values with GWI normal reference values reported in current literature to determine whether our observed mean GWI in a cohort of patients with sepsis deviates significantly from these established benchmarks in an average healthy population. Methods This report was a retrospective analysis of 179 consecutive patients ≥18 years with sepsis as defined by the Third International Consensus Definitions for Sepsis and Septic Shock who presented at our center from January 2020 to October 2023. LVEF (%) and GWI (mm Hg%) were reported as mean (±SD). A one-sample t-test was used to determine if the mean MWI for males and females diagnosed with sepsis at our center significantly differed from the reported GWI literature of reference patients without sepsis. Results Males (n=90, 50.3%) from our center had a significantly lower GWI mean (1353.06 ± 490.75) than the literature-reported male reference value of 2062 (P < 0.001) and a 95% confidence interval (1250 to 1455.84). See the Table. In 89 (49.7%) females with sepsis, mean GWI was also significantly lower, 1511 ± 595.79 (P < 0.001), than the normal reported female reference GWI value 2155 with a 95% CI (1385.57 to 1636.58). The pooled GWI mean was 1440.0±561.8 (ref: 2118±277). Septic males and females had preserved mean LVEF values of 51.6±13.11 and 56.8±14.4, respectively. The pooled mean LVEF was 54.0±13.8. Conclusion These findings revealed preserved LVEF alongside decreased global work index in patients with sepsis. To our knowledge, this is the first description of MW indices in septic patients. The results highlight the importance of further investigations into the role of MW indices in sepsis and the potential for these indices to enhance our understanding and clinical approach to myocardial dysfunction in sepsis.

The effect of afterload on right ventricular pacing-induced left ventricular dysfunction: a translational study

Abstract Introduction Right ventricular (RV) pacing (RVP) impairs left ventricular (LV) function. Nevertheless, the interaction between arterial afterload and RVP-associated LV dysfunction has not been investigated yet. Purpose We sought to examine the effect of afterload on RVP-evoked LV hemodynamic changes in patients with aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI) as well as in a small animal model of sustained LV pressure overload (PO). Methods Thirty-five patients with AS and a previously implanted pacemaker underwent detailed echocardiographic examination immediately before TAVI and also on the second postoperative day. The ultrasound measurements were carried out during intrinsic, narrow QRS rhythm and during frequency-matched RVP as well. Global myocardial work index (GMWI) was calculated to assess LV contractility. In parallel, LV pressure-volume analysis was performed in Wistar rats with transverse aortic constriction (TAC) or sham operation (Sham) during intrinsic narrow QRS rhythm (termed as TAC-Vsense and Sham-Vsense) as well as during RVP (termed as TAC-Vpace and Sham-Vpace). RVP was achieved in rats by an octopolar electrophysiology catheter placed in the RV. Results RVP decreased LV contractility in AS patients before and after TAVI as well. Nevertheless, the extent of RVP-evoked LV dysfunction was alleviated following pressure unloading (ΔGMWI: -37±7 vs. -25±8%, before TAVI vs. after TAVI, P<0.05). Similarly, although RVP was associated with reduced LV contractility in both the TAC (the slope of the maximum rate of LV pressure rise-end-diastolic volume relation [dPdtmax-EDV]: 92±8 vs. 53±6mmHg/s/µl, TAC-Vsense vs. TAC-Vpace; P<0.05) and Sham groups (dPdtmax-EDV: 74±5 vs. 60±9 mmHg/s/µl, Sham-Vsense vs. Sham-Vpace; P<0.05), the negative inotropic effect of RVP was found to be stronger in the TAC compared to the Sham group (ΔdPdtmax-EDV: -42±4 vs. -19±6%; TAC vs. Sham, P<0.01). Furthermore, reduction of the maximal rate of LV pressure decrease (ΔdPdtmin: -20±3 vs. -5±5%, TAC vs. Sham, P<0.01) and prolongation of the active relaxation time constant (Δτ: 22±3 vs. 6±3%, TAC vs. Sham, P<0.01) also occurred to a greater extent in case of sustained LV PO, indicating augmented diastolic dysfunction. Conclusion Our translational results indicate that RVP-induced LV dysfunction might be afterload dependent.

Right ventricular myocardial work in heart failure with preserved ejection fraction: insights from invasive cardiopulmonary exercise testing

Abstract Backgrounds Symptoms of heart failure with preserved ejection fraction (HFpEF) is closely related to elevated pulmonary capillary wedge pressure (PCWP) during exercise. The understanding of right ventricle myocardial work, assessing of right ventricular (RV) function utilizing RV pressure–strain loops, in HFpEF is lacking. Methods The study population underwent invasive cardiopulmonary exercise tests, measuring pressures at rest and during exercise to identify HFpEF. Echocardiography assessed LV and RV parameters. Right ventricular myocardial work was calculated using strain-rate and pressure curves, matching them with ECG data. RV global constructive work (RVGCW), RV global work index (RVGWI), RV global wasted work (RVGWW), and RV global work efficiency (RVGWE) were analysed and compared with invasively measured PCWP at resting and peak exercise. Results Between November 2017 and July 2023, 41 patients with adequate data were enrolled, and 21 were diagnosed with HFpEF. There were no significant differences in various echocardiographic parameters between HFpEF and non-HFpEF groups, except higher post-exercise PCWP and mean pulmonary artery pressure. HFpEF patients had higher RVGWW and lower RVGWE. RVGWW and RVGWE had higher predictive ability for HFpEF diagnosis compared to other echocardiographic parameters. While RVGCW (r = 0.0.504, P = 0.001 and r = 0.430, P = 0.006, respectively) and RVGWW correlated (r = 0.408, P = 0.008 and r = 0.621, P <0.001, respectively) with post-exercise ∆PCWP and exercise PCWP, only RVGWW (β=1.981, P=0.044 and β=4.323, p<0.001) being independently associated with both after adjustment for confounding factors. Conclusions RVGWW is a novel parameter that provides an integrative analysis of RV systolic function and correlates more closely with post-exercise ∆PCWP than other standard echocardiographic parameters in HFpEF.

Right ventricular myocardial work: a step forward for the assessment of right ventricular to pulmonary artery coupling

Abstract Background Right ventricular myocardial work (RVMW) is a novel method for non-invasive assessment of right ventricular (RV) function. By integrating RV global longitudinal strain as systolic function parameter, pulmonary systolic and diastolic pressures as afterload indices, and pulmonary and tricuspid valves timings, RVMW could provide a more comprehensive evaluation of RV function. Purpose The aim of this study was to assess patterns of RVMW indices in patients with preserved and impaired RV to pulmonary artery (PA) coupling (RVAC), as assessed by RV free wall longitudinal strain/pulmonary artery systolic pressure (RVFWLS/PASP) ratio. Methods We studied by echocardiography 158 consecutive patients with stable HF and left ventricular (LV) systolic dysfunction (LV ejection fraction < 50%). RVAC was assessed by RVFWLS/PASP and patients were grouped according to the median value. Four parameters of RVMW were obtained: RV global work index (RVGWI), RV global constructive work (RVGCW), RV global wasted work (RVGWW) and RV global work efficiency (RVGWE). Results According to RVFWLS/PASP ratio, patients were divided into two groups: A) preserved RVAC (RVFWLS/PASP ratio ≥ 0.51; N=84) and B) impaired RVAC (RVFWLS/PASP ratio < 0.51; N= 74). Both RVGWI (371±156 vs 384±207 mmHg%, P=NS) and RVGCW (449±171 vs 516±249 mmHg%, P=NS) did not significantly differ between the two groups (figure 1). However, group B (impaired RVAC) showed significantly greater RV wasted work (94±69 vs 44±30 mmHg%, P=0.0001) and significantly lower RV work efficiency (80±13 vs 88±8 %, P=0.0001) compared to group A (preserved RVAC, figure 2). Conclusions RVMW provided new insight in the RV function assessment, highlighting lower efficiency due to higher wasted work in RV to PA uncoupled patients.Figure 1Figure 2