Novel Method For Evaluation Research Articles

Argininemia: Pathophysiology and Novel Methods for Evaluation of the Disease

Argininemia or arginase-1 deficiency constitutes a rare, genetic, metabolic disorder caused by mutations in arginase 1—the last enzyme of the urea cycle—that hydrolyses L-arginine to ornithine and urea. The disease is associated with progressive development of spasticity and other symptoms, including seizures, developmental delay, cognitive impairment, and hepatic pathology. The present review attempts to summarize the current knowledge on the pathophysiology of the disease and highlight novel methods for its evaluation. Different factors, such as the accumulation of arginine, ammonia, and guanidino compounds, act as neurotoxins and may account for the neurological sequelae observed in the disease. New markers, such as arginine/ornithine ratio along with metabolomics, machine learning algorithms, and genetic methods, can be useful in the early diagnosis of argininemia, while mobile phone apps can assist argininemic patients in adhering to the strict diet required. Neurophysiology, multi-modal imaging, and new modelling methods, such as induced pluripotent stem cells, hold promise for providing new insights into the pathophysiology of the disease. There are still many uncertainties regarding the underlying mechanisms of argininemia, but the use of novel modelling methods and new technology can lead to the decipherment of its pathophysiology, improvement of diagnostic accuracy, and better disease management.

Novel method for evaluation of stress assisted corrosion through compact tension specimens to assess material compatibility in latent heat thermal energy storage systems

The next generation Concentrated Solar Power (CSP) plants integrated with Thermal Energy Storage (TES) offer a promising solution for dispatchability, reliability, and economic concerns associated with renewable energy technologies. However, the expected operational life of up to 30 years proves to be a major challenge due to the impact of high temperatures and corrosive eutectic salts utilised in the latent heat TES systems. Additionally, the system is under varying degrees of stress that can accelerate corrosion mechanisms. Unfortunately, this stress corrosion relationship is often neglected during the material compatibility assessment. This study utilises a novel static immersion testing approach with three designs of modified Compact Tension (CT) specimens manufactured from AISI 316L to investigate the interaction of alloys under stress with various eutectic salts at up to 750 °C for up to 1000 Hours. The results indicate that oxidation is accelerated up to four times and Intergranular Corrosion (IGC) up to two times in the high-stress region of the test samples. Furthermore, the findings suggest that static immersion testing using CT specimens can be regarded as an effective approach to assess the influence of stress on corrosion and conduct a reliable material assessment for latent heat TES systems and CSP plants.

Digitally supported health care; evaluation approaches to a complex intervention embedded in a tria

Abstract Many important health care interventions do not fit the classic RCT paradigm. Drug trials have struggled with issues of non-compliance and selective withdrawal. Surgical researchers have done extensive work on incorporating operator skills and experience into trial settings. Working on innovative models of care delivery related issues arise. As part of an EU funded multi-centre stepped-wedge trial, GERONTE, of nurse-led, digitally supported, health care coordination for older people with cancer and other significant co-morbidity, we have developed and tested an outline of a novel method of evaluation, drawing on realist evaluation. There are three pieces, first the central trial outcome, quality of life, for those in the trial, analysed by intention-to-treat. Second an economic evaluation, based on care pathways, and collecting costs during the control and intervention phases in 16 centres, in 3 countries. Third, a realist evaluation of implementation, with 3 phases in each site, the first of which is underway. 1) Readiness to implement GERONTE, and documenting current practice, and identifying barriers and facilitators for change with clinical staff, technical staff and administrators; 2) Experience of implementation as the intervention is brought in over the course of the study; 3) Experience in keeping GERONTE running after the initial implementation phase. Early results show great site to site variability, in practice and in resources, but common barriers are data handling and sharing. In each phase, guided by ideas from participatory rapid appraisal, we stress the rapid feedback to participants, of their response, and the synthesis of responses to support successful implementation. One aim is to prepare an implementation guide to support future deployments of GERONTE and similar projects, drawing on lessons from all 16 sites, and filling a gap in the literature. GERONTE is funded by the Horizon 2020 research and innovation programme under grant agreement No 945218. Key messages • Innovative health care delivery, such as integrated care, requires complex assessment approaches, designed for the specific innovation. • Site-to-site variability in the implementation of novel care pathways and approaches is the norm, and needs to be considered at design stage.

Evaluation of Neutron Cross-Section Data Using Gaussian Mixture Model and Digital Filter

For the accurate estimation of neutron cross-section data, evaluation of nuclear data is mandatory to fulfill the need of nuclear science and technology. In this work, the evaluation of 232Th(n,2n)231Th, 241Am(n,2n)240Am, 100Mo(n,2n)99Mo, and 96Mo(n,p)96Nb reaction cross-section data is carried out using a novel method. This novel method of evaluation employs a cluster-based piecewise evaluation followed by a digital filter for merging the evaluated curves. The clusters in the experimental data and model data are identified using the probabilistic method of the Gaussian Mixture Model. The clustered experimental data are then regressed using the polynomial regression technique. The model data are generated using the Talys 1.9 code, and the model deficiency due to the complex random nature of nuclear reactions is also accounted here using chi-squared analysis. Evaluation in each cluster is then carried out independently using the popular Kalman filter technique. For obtaining a single smooth evaluated curve for the whole energy range, the popular smoothing digital filter, the Savitzky-Golay Filter, is employed for the first time in nuclear data evaluation. The proposed evaluated curves and existing evaluated curves of 232Th(n,2n)231Th, 241Am(n,2n)240Am, 100Mo(n,2n)99Mo, and 96Mo(n,p)96Nb reactions from nuclear data libraries such as ENDF/BVIII.0, JEFF-3.3, JENDL-4.0, CENDL-3.1, and TENDL 2021 are compared and found to be in good agreement. It is also found that generally, evaluation methods are data dependent, and so, a single evaluation method may not be applicable for all reactions of all nuclides. Since piecewise evaluation is cluster dependent, selecting the appropriate cluster makes this method robust for almost all reactions of all nuclides. Also, it is proven that this novel method of evaluation is a promising method demonstrating the potential of this approach for evaluation based on the chi-squared goodness-of-fit test with respect to standard evaluated library ENDF/BVIII.0 and experimental data.

A novel method for evaluation of spatial characteristics in a gas solid separation fluidized bed

This study investigates the complex spatial characteristics of a gas-solid dense-phase fluidized bed for a separation system. A custom-designed perspex bed, equipped with multi small holes and different distributors, was used to explore gas-solid suspension characteristics. The results show that there is a certain spatial heterogeneity in the density of the gas-solid separation fluidized bed. The spatial heterogeneity of gas-solid fluidized beds is characterized by global and local dependence. An empirical model that predicts the relative solid mass flow rate was proposed. GeoDetector technology (including a factor detector, interaction detector, risk detector, and ecological detector) was first introduced to quantify the spatial characteristics of a gas-solid fluidized bed. The influence of each factor on the spatial heterogeneity of particle solid mass flow rate follows the order: axial position > gas velocity > radial position > air distributor. The interactive relationship between variables on the spatial characteristics of gas-solid separation fluidization shows a nonlinear enhancement.

A novel method for evaluation of the spontaneous imbibition process in tight reservoir rocks: Mathematical model and experimental verification

Spontaneous imbibition driven by capillary forces is essential for the development of oil and gas resources because it can significantly influence the oil recovery of tight reservoirs. But limited by traditional experimental methods, the existing mathematical models lack applicability to complex tight reservoir rocks. Therefore, to better predict water imbibition in tight reservoirs, this paper proposes a new spontaneous imbibition model based on modifications of the classical Handy model. Two important parameters, the average capillary pressure, and the imbibition permeability are derived using a nuclear magnetic resonance spectroscopy method to quantify the macroscopic driving force and percolation ability of the complex pore network. Furthermore, combined experiments of co-current spontaneous imbibition experiments and transverse relaxation time analysis on four shale core plug samples are conducted to verify the new model. Results show the imbibition process can be modeled successfully before the imbibition volume reaches 85% of the maximum imbibition volume, and two continuous stages: the early/free imbibition stage and the later/limited imbibition stage, are then subdivided according to the applicability of our model. Considering the heterogeneity of the pore network in shale samples, it can be inferred that an uneven imbibition front occurred during the imbibition process. In all, this model enriches the classical imbibition theory and provides a new approach to analyzing the imbibition of fracturing fluids in complex tight reservoirs.

A Novel Method for Evaluation of Ore Minerals Based on Optical Microscopy and Image Analysis: Preliminary Results

Natural or artificial light allows us to see and analyze matter with our eyes, which are the first tools used in several experiments. In geosciences, particularly in mineralogy, light is used for optical microscopy observations. Reflected and transmitted light applied to the study of ore deposits can be useful to discriminate between gangue from precious phases. Knowledge of the structural and morphological characteristics, combined with the quantitative evaluation of mineral abundance, is fundamental for determining the grade of ore deposits. The accuracy and reliability of the information are closely linked to the ability of the mineralogist, who more and more often uses Scanning Electron technology and automated mineralogy systems to validate the observations or solve complex mineralogy. While highly accurate, these methods are often prohibitively expensive. The use of image analysis using standard algorithms and artificial intelligence, available as open source, and commercial packages (such as ImageJ, Fiji or MATLAB), can provide advantages in fast, cost-effective, and robust mineral analysis. Recently, the application of neural networks provided increasingly effective image analysis and, among the different types of neural networks available today, the self-organizing maps of Kohonen (SOM) seem to be among the most promising, given their capacity to receive many images as inputs and reduce them to a low number of neuronal outputs that represent all the input characteristics in a lower-dimensional space. In this work, we will show the preliminary results of a new method based on SOM and the combined use of images acquired in transmitted and reflected light to reconstruct false 3D surfaces, which were able to show the presence of intergrow between gangue phases and precious minerals.

A novel method for the evaluation of ejector based on a virtual nozzle and two indexes

This paper presents a novel method for ejector evaluation by developing a virtual nozzle, which provides the ejector’s maximum ability to overcome its back pressure and the minimum constant cross-section area based on two newly-derived evaluation indexes. The method was developed based on the assumption that the total energy and the ratio of dynamic enthalpy to total energy before normal shock of the virtual nozzle are the same as those of the real ejector. Under the condition that the initial state of the virtual nozzle is the same as that of the primary fluid of the ejector, two evaluation indexes, which include the relative pressure ratio and the relative area ratio, were derived to indicate the extent to which the ability to overcome back pressure and area demand deviate from the benchmark obtained from the virtual nozzle. Using the new method, the case studies of ejector evaluation were carried out involving with theoretical data of 13 refrigerants selected as working fluid of ejector and experimental data of four refrigerants. And the relationship between the two indexes was expressed by a high-accuracy fitting correlation equation that was validated by both theoretical calculation and experimental data and was found meaningful.

A Novel Method for Evaluation of the Spontaneous Imbibition Process in Tight Reservoir Rocks: Mathematical Model and Experimental Verification

A Novel Method for Evaluation of the Spontaneous Imbibition Process in Tight Reservoir Rocks: Mathematical Model and Experimental Verification

Evaluation of the effectiveness of the chronic heart failure therapy using the device cardiac contractility modulation according to the new non-invasive method of the myocardium work analysis

Aim To analyze echocardiographic parameters that reflect left ventricular (LV) myocardial contractility, using a novel method for evaluation of myocardial performance in patients with chronic heart failure (CHF) and atrial fibrillation (AF) during heart contractility modulation (HCM).Material and methods Standard echocardiographic parameters and indexes of myocardial strain and work were analyzed for 66 patients (52 men and 14 women; median age, 60 [54; 66] years). 36 patients had paroxysmal AF and 30 patients had permanent AF. All patients had CHF with a duration of 17 [4; 60] months; duration of AF was 12 [6; 36] months. At baseline, the left ventricular ejection fraction (LV EF) was 33 [27; 37] %.Results After one year of HCM, LV EF significantly increased from 33 [27; 37] to 38 [33; 44] % (р=0.001). Also, there were improvements in the myocardial global longitudinal strain (from -6.00 [ - 8; - 4] to -8 [ - 10; - 6] %; р=0.001) and parameters of myocardial work, including the global work efficiency (from 74 [65; 79] to 80 [73; 87] mm Hg%; р=0.001), global constructive work (from 699 [516; 940] to 882 [714; 1242] mm Hg%; р=0.001), and global myocardial work index (from 460 [339; 723] to 668 [497; 943] mm Hg%; р=0.001). A segmentary analysis of LV work parameters showed positive changes in the myocardial constructive work in the area of the interventricular septal apical segment (at baseline, 844 [614; 1224]; after HCM, 1027 [800; 1520] mm Hg%; р=0.05) and the medium segment of the LV anteroseptal wall (at baseline, 593 [312; 1000]; after HCM, 877 [494; 1145] mm Hg%; р=0.05).Conclusion This method for analysis of the myocardial work provides a more detailed examination of LV structural and functional remodeling and mechanisms for its effects on the LV contractile function in patients with CHF. This method is promising and merits further study in various clinical situations.

A Novel Method for Evaluation of Chromium Evaporation from Solid Oxide Fuel Cells Interconnects: A Feasibility Study

The evaporation of volatile chromium species from ferritic stainless steels (FSSs) used as interconnect is well-known as degradation source for planar solid oxide fuel cell (SOFC) stacks. This work presents a feasibility study to quantify chromium evaporation from FSSs. It is based on measuring carbon dioxide produced by an intermediate reaction. Cr evaporated is collected by sodium carbonate forming sodium chromate and carbon dioxide. Measuring the resulting carbon dioxide allowed to quantify online the amount of reacted chromium with the carbonates. The post-experiment quantification of sodium chromate confirmed the applicability of the proposed method.

Revealing the mechanisms and the material basis of Rubia cordifolia L. on abnormal uterine bleeding with uniting simultaneous determination of four components and systematic pharmacology approach-experimental validation

The roots of Rubia cordifolia L. (RCL) have become an important medicine for abnormal uterine bleeding (AUB) and hemorrhage syndrome in Traditional Asian medicine. However, the underlying mechanism and the material basis of RCL for treating AUB has not been fully elucidated. In this study, quantitative evaluation of quinones, systematic pharmacology and experimental verification were adopted. Firstly, the Disease-Ingredient-Target network was established by Cytoscape, which was consistent with 23 compounds and 47 target genes. The hub targets were discovered by Maximal Clique Centrality (MCC) method with Cytohubba plugins of Cytoscape, and top 20 nodes were ranked by MCC. It was assumed that mollugin is the main ingredient of RCL for treating AUB. Pathways on which RCL acted were obtained from observation of its biological functions, KEGG pathways and Reactome pathway enrichment analysis. The possible mechanism of RCL for treating AUB was revealed for improvment of the blood clotting system, blood circulation, arachidonic acid metabolism and inflammation. Then, a novel method for evaluating the quality of RCL was established, and the content of mollugin in RCL was the higher than others. Finally, pharmacologic experiments confirmed that RCL could improve the inflammation by inhibiting the activity of COX-2 and cPLA2 enzyme, ameliorate blood hypercoagulability by affecting coagulation cascade and fibrinolytic system. It was found that RCL inhibited the expression COX-2 and PAI-1 by reducing HIF-1α expression. The trend of each index of mollugin was consistent with that of RCL, indicating that it played an important role in RCL for treating AUB. The above results could provide a novel method for the quality evaluation of RCL and was expected to give us more important information regarding the use of RCL as a promising drug candidate for AUB, offering a fertility preserving medical, non-hormonal treatment choose for women with AUB.

Accuracy of short tandem repeats genotyping tools in whole exome sequencing data

Background: Short tandem repeats are an important source of genetic variation. They are highly mutable and repeat expansions are associated dozens of human disorders, such as Huntington's disease and spinocerebellar ataxias. Technical advantages in sequencing technology have made it possible to analyse these repeats at large scale; however, accurate genotyping is still a challenging task. We compared four different short tandem repeats genotyping tools on whole exome sequencing data to determine their genotyping performance and limits, which will aid other researchers in choosing a suitable tool and parameters for analysis. Methods: The analysis was performed on the Simons Simplex Collection dataset, where we used a novel method of evaluation with accuracy determined by the rate of homozygous calls on the X chromosome of male samples. In total we analysed 433 samples and around a million genotypes for evaluating tools on whole exome sequencing data. Results: We determined a relatively good performance of all tools when genotyping repeats of 3-6 bp in length, which could be improved with coverage and quality score filtering. However, genotyping homopolymers was challenging for all tools and a high error rate was present across different thresholds of coverage and quality scores. Interestingly, dinucleotide repeats displayed a high error rate as well, which was found to be mainly caused by the AC/TG repeats. Overall, LobSTR was able to make the most calls and was also the fastest tool, while RepeatSeq and HipSTR exhibited the lowest heterozygous error rate at low coverage. Conclusions: All tools have different strengths and weaknesses and the choice may depend on the application. In this analysis we demonstrated the effect of using different filtering parameters and offered recommendations based on the trade-off between the best accuracy of genotyping and the highest number of calls.

Virtual Storage-Based Model for Estimation of Economic Benefits of Electric Vehicles in Renewable Portfolios

The expected increase in the presence of electric vehicles raises numerous questions regarding their impact on the market relations. Depending on the agreement between the involved parties, the position of EVs changes from passive (traditional role) to active. Active EVs are beneficial for variability and uncertainty-intense modern power systems. To enable this transition, a suitable framework in the form of agreements is required in order to establish the terms and responsibilities. Following the presented agreements, we propose a novel method for evaluation of the benefits that the newly added EVs bring to the portfolio. The method comprises two steps, a Monte Carlo simulation of the EV driving/charging patterns and an optimization model for market related decision making. The method results in the estimates on economic savings resulting from adding EVs to portfolios. An illustrative example is used in order to give an idea of the range of the benefits.

Prediction of part distortion in re-contouring processes

An important step in turbine repair is the re-contouring process as it determines part and surface properties. Re-contouring is performed subsequently to the material deposit and has to be adapted to each repair case individually. Especially, part distortion is a crucial aspect in terms of quality and has to be considered in process design.This paper introduces a novel method for evaluation of re-contouring processes regarding part quality and, especially, part distortion. For this purpose, a simulation model for calculating local cutting conditions is introduced and validated experimentally. The validation is carried out for a thin-walled analogue part. The results reveal a clear dependency between the absolute part distortion and the surface generating cut volume (SGCV).

A Novel Method for Evaluation of Right Ventricular Performance during Left Ventricular Assist Device Implantation

Left ventricular assist devices (LVAD) are utilized in patients diagnosed with advanced heart failure. Right ventricular (RV) failure can affect up to 20% of patients undergoing LVAD implantation. In this case study, we evaluated perioperative RV performance with simultaneous use of Swan-Ganz catheterization and high-fidelity conductance catheters to generate real time RV pressure- volume (PV) loops. A 75- year old male patient undergoing LVAD implantation was chosen for evaluation. A high-fidelity conductance catheter was advanced into the RV. The catheter was removed on postoperative day one. Data obtained from the catheter were used to evaluate RV work, contractility, diastolic function, and compliance. These results were compared to standard measurements of the patient's clinical status and biventricular performance. Consent and IRB approval was obtained as part of an ongoing study. The patient developed RV dysfunction in the immediate perioperative period, as demonstrated by increasing central venous pressure to pulmonary artery pressure ratio, decreased cardiac index, and evidence of elevated filling pressures by echocardiogram. Using a high-fidelity catheter, we demonstrated a uniform reduction in preload recruitable stroke work and Starling contractile index on postoperative day one. Pressure-volume loops initially demonstrated appropriate ventricular unloading, however RV dysfunction was exposed with changes in loading conditions over time (figure 1). Pressure-volume loop analysis represents a novel method for evaluation of RV performance during LVAD implantation. Compared to standard monitoring, PV loops provide increased granularity in understanding RV function.

Accuracy of short tandem repeats genotyping tools in whole exome sequencing data.

Background: Short tandem repeats are an important source of genetic variation. They are highly mutable and repeat expansions are associated dozens of human disorders, such as Huntington's disease and spinocerebellar ataxias. Technical advantages in sequencing technology have made it possible to analyse these repeats at large scale; however, accurate genotyping is still a challenging task. We compared four different short tandem repeats genotyping tools on whole exome sequencing data to determine their genotyping performance and limits, which will aid other researchers in choosing a suitable tool and parameters for analysis. Methods: The analysis was performed on the Simons Simplex Collection dataset, where we used a novel method of evaluation with accuracy determined by the rate of homozygous calls on the X chromosome of male samples. In total we analysed 433 samples and around a million genotypes for evaluating tools on whole exome sequencing data. Results: We determined a relatively good performance of all tools when genotyping repeats of 3-6 bp in length, which could be improved with coverage and quality score filtering. However, genotyping homopolymers was challenging for all tools and a high error rate was present across different thresholds of coverage and quality scores. Interestingly, dinucleotide repeats displayed a high error rate as well, which was found to be mainly caused by the AC/TG repeats. Overall, LobSTR was able to make the most calls and was also the fastest tool, while RepeatSeq and HipSTR exhibited the lowest heterozygous error rate at low coverage. Conclusions: All tools have different strengths and weaknesses and the choice may depend on the application. In this analysis we demonstrated the effect of using different filtering parameters and offered recommendations based on the trade-off between the best accuracy of genotyping and the highest number of calls.

A Novel Method for Evaluation of Ocular Torsion Angle by Optical Coherence Tomography.

PurposeThe Glaucoma Module Premium Edition (GMPE) software for the SPECTRALIS optical coherence tomography (OCT) is able to automatically track the anatomic centers of both the fovea and the optic disc. We investigated the efficacy of the OCT in measuring the ocular torsion angle before and after strabismus surgery.MethodsBetween June 2017 and December 2018, 40 patients with cyclodeviation who had undergone strabismus surgery at Hyogo College of Medicine were enrolled. Ocular torsion angle measurements, including OCT and nonmydriatic fundus camera for objective measurements and synoptophore for subjective measurements, were performed before surgery and 1 day after surgery.ResultsThe ocular torsion angles were measured as follows: synoptophore preoperative (–8.8° ± 4.1°) and postoperative (–3.1° ± 2.8°), fundus photography preoperative (–27.2° ± 6.4°) and postoperative (–18.6° ± 5.9°), and OCT preoperative (–25.9° ± 6.8°) and postoperative (–18.2° ± 5.8°). In all cases, symptoms related to cyclodeviation resolved postoperatively. All measurements were positively correlated before surgery. Postoperatively, changes in all measurements were also correlated. However, all synoptophore-related data were underestimated when compared with OCT and fundus photography.ConclusionsFor measuring the ocular torsion angle, the OCT-based technology GMPE appears to provide information regarding anatomic fundus torsion that is similar to that obtained using fundus photography.Translational RelevanceThis new objective measurement for the ocular torsion angle is helpful for treating cyclotropia.

New Horizons in the use of routine data for ageing research.

The past three decades have seen a steady increase in the availability of routinely collected health and social care data and the processing power to analyse it. These developments represent a major opportunity for ageing research, especially with the integration of different datasets across traditional boundaries of health and social care, for prognostic research and novel evaluations of interventions with representative populations of older people. However, there are considerable challenges in using routine data at the level of coding, data analysis and in the application of findings to everyday care. New Horizons in applying routine data to investigate novel questions in ageing research require a collaborative approach between clinicians, data scientists, biostatisticians, epidemiologists and trial methodologists. This requires building capacity for the next generation of research leaders in this important area. There is a need to develop consensus code lists and standardised, validated algorithms for common conditions and outcomes that are relevant for older people to maximise the potential of routine data research in this group. Lastly, we must help drive the application of routine data to improve the care of older people, through the development of novel methods for evaluation of interventions using routine data infrastructure. We believe that harnessing routine data can help address knowledge gaps for older people living with multiple conditions and frailty, and design interventions and pathways of care to address the complex health issues we face in caring for older people.

P1575 Preserved myocardial work efficiency after transcatheter aortic valve implantation-induced left bundle branch block

Abstract Background Left bundle branch block (LBBB) frequently complicates transcatheter aortic valve implantation (TAVI), but may not induce classical mechanical dyssynchrony typically observed in heart failure patients with LBBB. Non-invasive estimated myocardial work by pressure strain-loops is a novel method for evaluation of left ventricular (LV) performance including loading conditions and identifies responders to cardiac resynchronization therapy. Assessment of myocardial work in TAVI-induced LBBB has, however, not been performed earlier. Purpose We aimed to evaluate myocardial performance in TAVI-induced LBBB by myocardial work. Methods Patients with severe aortic stenosis (AS) and normal ventricular conduction undergoing transfemoral TAVI were included. TAVI-induced LBBB was defined according to strict ECG criteria. In addition to standard echocardiographic parameters, we performed speckle tracking echocardiography (STE) within 2 days post procedure. Post-procedural myocardial work was estimated by commercially available software, combining LV strain by STE and a non-invasively estimated LV pressure curve. Peak systolic LV pressure was assumed to be equal to the sum of peak arterial cuff pressure and mean aortic valve pressure gradient. The proportion of constructive work relative to the sum of wasted and constructive work was expressed as myocardial work efficiency (Figure). A global work efficiency < 90 % was considered abnormal according to the recently published EACVI NORRE study. Results We included 109 consecutive patients undergoing TAVI (83 ± 7 years old, 54 % women, logistic Euroscore 16 ± 10) with severe AS (valve area 0.7 ± 0.2 cm2, mean transvalvular gradient 54 ± 18 mmHg), QRS duration 94 ± 10 ms, and a relatively preserved LV ejection fraction (54 ± 9%). New-onset LBBB was observed in 28 patients (26 %) after TAVI. Although post-procedural myocardial work efficiency was slightly better in patients who retained normal ventricular conduction than those with TAVI-induced LBBB (93.6 ± 2.5% vs 91.2 ± 3.4%, p = 0.004), both groups of patients had global myocardial work efficiency within the normal reference range. Conclusions Patients with TAVI-induced LBBB have preserved work efficiency despite gross electrical block satisfying strict ECG criteria. The reduced myocardial work efficiency in TAVI-induced LBBB was within the reference range of normal in the recently published EACVI NORRE study. The preservation of myocardial work in TAVI-induced LBBB may explain why LBBB as a complication to TAVI does not necessarily imply poor prognosis. Abstract P1575 Figure.