Dedicated Software Package Research Articles

1184 Left atrial volumes by 3-dimensional but not 2-dimensional echocardiography predict cardiac death and events in patients with heart failure with reduced ejection fraction

Abstract Background Patients with heart failure with reduced ejection fraction (HFrEF) are at high risk for mortality and morbidity. Left atrial volumes (LAVs), measured by 2-dimensional echocardiography (2DE), have been suggested as possible prognostic markers. However, LAVs measured by 2DE are prone to errors due to geometric assumptions and increased variability, whereas 3-dimensional echocardiography (3DE) has been proved to be a more accurate and reproducible method for volume assessment. Purpose To assess the comparative prognostic value of LAVs, measured by 2DE and 3DE, in patients with ischemic and non-ischemic HFrEF, on best clinical care. Methods 135 consecutive patients (59 ± 15 years, 91 males), diagnosed with HFrEF, in sinus rhythm, were assessed by 2DE and 3DE, including full-volume multi-beat acquisitions of the LA and left ventricle (LV). Maximal and minimal indexed LAVs were measured from the 2DE datasets using biplane area-length formula (2D_LAVmax and 2D_LAVmin); and from the 3DE datasets using a dedicated software package (3D_LAVmax and 3D_LAVmin). Patients were followed for 23 ± 14 months after the index event. Primary outcome was cardiac death (CD); secondary outcomes were: 1) HF hospitalization (HFH); 2) a composite cardiac events (CE) end-point, of cardiac death or hospitalization for heart failure, myocardial infarction, coronary revascularization, arrhythmias, or cardiac resynchronization therapy. Results 26 CD, 32 HFH, and 48 CE occurred during follow-up. 2DE and 3DE measurements are in the table. LAVs measured by 2DE did not correlate with outcome. However, 3D_LAVmax and 3D_LAVmin correlated with CD (r = 0.40 and r = 0.38) and CE (r = 0.30 and r = 0.29), all p < 0.05, but not with HFH. By multivariate linear regression analysis, only 3D_LAVmax and 3D_LAVmin were independent predictors for CD and CE, in patients with HFrEF (r²=0.30 and r²=0.32; p < 0.01). Conclusion In patients with HFrEF, LA volumes measured by 3DE, but not by 2DE, were independent predictors for cardiac death and events. However, even LA volumes by 3DE did not have predictive value for future HF rehospitalizations. Echo features for patients with HFrEF 3D end-diastolic LV volume (ml/m2) 101 ± 32 3D end-systolic LV volume (ml/m2) 71 ± 29 3D LV ejection fraction (%) 30 ± 8 2D_LAVmax (ml/m2) 52 ± 18 2D_LAVmin (ml/m²) 31 ± 15 3D_LAVmax (ml/m2) 43 ± 18 3D_LAVmin (ml/m2) 29 ± 16

Are systemic antibiotics required during and after dacryocystitis-related dacryocystorhinostomy?

ABSTRACT Purpose To compare the outcomes of patients with and without a history of dacryocystitis that undergo dacryocystorhinostomy without systemic intra- and post-operative antibiotics. Methods A retrospective review was performed to identify all cases of patients that received surgery under this paradigm and had at least three months of follow up care. Key demographic and outcome data were captured, and a statistical analysis was performed via a dedicated software package (Microsoft Excel, Redmond, WA). Results For the study period, 83 patients without and 69 patients with a history of dacryocystitis were identified, and the two groups were not statistically significantly different in age, gender, or postoperative follow up duration (mean = 6.4 months for patients without and 6.3 months for those with dacryocystitis, respectively). No patient developed a postoperative infection or a recurrence of dacryocystitis during the follow up period. Discussion While many surgeons routinely use systemic antibiotics in patients with a history of dacryocystitis who undergo dacryocystorhinostomy, these agents may not be necessary. As a result, patients may be able to avoid the complications and side effects inherent to systemic antibiotics. Large-scale, prospective studies will likely help to further clarify this issue.

A low‐cost underwater particle tracking velocimetry system for measuring in situ particle flux and sedimentation rate in low‐turbulence environments

AbstractWe describe a low‐cost three‐dimensional underwater particle tracking velocimetry system to directly measure particle settling rate and flux in low‐turbulence aquatic environments. The system consists of two waterproof cameras that acquire stereoscopic videos of sinking particles at 48 frames s−1 over a tunable sampling volume of about 45 × 25 × 24 cm. A dedicated software package has been developed to allow evaluation of particle velocities, concentration and flux, but also of morphometric parameters such as particle area, sinking angle, shape irregularity, and density. Our method offers several advantages over traditional approaches, like sediment trap or expensive in situ camera systems: (1) it does not require beforehand particle collection and handling; (2) it is not subjected to sediment trap biases from turbulence, horizontal advection, or presence of swimmers, that may alter particulate load and flux; (3) the camera system enables faster data processing and flux computation at higher spatial resolution; (4) apart from the particle settling rates, the particle size distribution, and morphology is determined. We tested the camera system in Lake Stechlin (Germany) in low turbulence and mean flow, and analyzed the morphological properties and settling rates of particles to determine their sinking behavior. The particle flux assessed from conventional sediment trap measurements agreed well with that determined by our system. By this, the low‐cost approach demonstrated its reliability in low turbulence environments and a strong potential to provide new insights into particulate carbon transport in aquatic systems. Extension of the method to more turbulent and advective conditions is also discussed.

A numerical approach for the bifurcation analysis of nonsmooth delay equations

Mathematical models based on nonsmooth dynamical systems with delay are widely used to understand complex phenomena, specially in biology, mechanics and control. Due to the infinite-dimensional nature of dynamical systems with delay, analytical studies of such models are difficult and can provide in general only limited results, in particular when some kind of nonsmooth phenomenon is involved, such as impacts, switches, impulses, etc. Consequently, numerical approximations are fundamental to gain both a quantitative and qualitative insight into the model dynamics, for instance via numerical continuation techniques. Due to the complex analytical framework and numerical challenges related to delayed nonsmooth systems, there exists so far no dedicated software package to carry out numerical continuation for such type of models. In the present work, we propose an approximation scheme for nonsmooth dynamical systems with delay that allows a numerical bifurcation analysis via continuation (path-following) methods, using existing numerical packages, such as COCO (Dankowicz and Schilder). The approximation scheme is based on the well-known fact that delay differential equations can be approximated via large systems of ODEs. The effectiveness of the proposed numerical scheme is tested on a case study given by a periodically forced impact oscillator driven by a time-delayed feedback controller.

3224Incremental benefit of left ventricular global longitudinal strain over clinical and left atrial parameters for predicting new-onset atrial fibrillation

Abstract Background Although LV hypertrophy and dysfunction are associated with atrial fibrillation (AF), AF often occurs in the absence of LV hypertrophy or reduced ejection fraction. The effect of subclinical LV dysfunction on AF has not been fully studied. Purpose We sought the association between subclinical LV dysfunction (measured with global longitudinal strain, GLS) and new-onset AF. Methods This observational study evaluated 531 consecutive patients (median age, 67 years [interquartile range, 56 to 78]; 56% male), without a history of AF who underwent strain echocardiography after cryptogenic stroke. The CHARGE-AF score was used to calculate the 5-year risk of developing AF. Standard echocardiographic parameters were measured, and speckle-tracking was used to measure LA (reservoir strain, pump strain, and conduit strain) and LV strain (GLS). A strain analysis was conducted using a dedicated software package, using R-R gating. The baseline clinical and echocardiographic parameters of the patients who developed AF and those who did not were compared. Results Over 2.5 years of follow-up, 61 patients (11%) had new-onset AF. Patients who developed AF were older, had a higher CHARGE-AF score, larger LA volume, worse LA strain, and worse GLS than those who did not. Areas under the receiver-operating curve for GLS (0.84) was comparable to CHARGE-AF (0.79), LA pump strain (0.83), and LA reservoir strain (0.85). In the nested Cox models, GLS demonstrated an independent and incremental predictive value over the clinical and LA parameters (Figure). Moreover, adding GLS to the combined clinical and LA parameters model resulted in a significantly improved reclassification (net reclassification improvement, 0.32; p=0.016). Importantly, the predictive value of GLS was confirmed in patients with abnormal LA volumes (LA volume index≥34ml/m2) but not in patients with normal LA volumes. Figure 1 Conclusion GLS is associated with new-onset AF, especially in patients with abnormal LA volumes. This effect is independent of and incremental to the clinical and LA parameters.

A vehicle/track/soil model using co-simulation between multibody dynamics and finite element analysis

ABSTRACTDue to the always growing computing power, virtual models become nowadays a popular mean to simulate complex problems such as vehicle stability, track settlement or ground-borne vibrations induced by railway vehicles. This paper presents a co-simulation model of a vehicle passing on a track that lays on a soil. The model is split into two subsystems that are the vehicle and track subdomains and the soil subdomain. The coupled vehicle/track subsystem is modeled into an in-house multibody dedicated software package while the soil is entirely modeled with the help of a finite element analysis software. The results obtained using Jacobi and Gauß-Seidel methods, two different co-simulation techniques, will be compared to an already validated two-step model. Moreover, besides the results, this paper presents the coupling technique used between both subsystems to allow co-simulation and depicts the data management between the two distinct simulation environments.

Validation of a new data-analysis software for multiple-peak analysis of γ spectra at ISIS pulsed Neutron and Muon Source

Abstract In this work, we present a multi-peak fitting code in order to establish a new protocol for the analysis of γ spectra at ISIS pulsed Neutron and Muon Source. The protocol, relying on the ROOT framework developed at CERN, has been tailored for the analysis of two specific gamma emitters – 241Am and 133Ba – and its results have been compared to those generated by Hypermet PC, a dedicated software package specifically devoted to the analysis of neutron induced γ -ray spectra and of widespread use since late 1990s. This new fitting procedure is scheduled for integration into the software for time-resolved prompt-gamma activation analysis, T-PGAA, currently under development at ISIS. T-PGAA allows for the simultaneous acquisition of photon energy and neutron time of flight, respectively, when prompt gamma rays are emitted by a sample after neutron absorption, essentially combining neutron resonance capture analysis (NRCA) and prompt gamma activation analysis (PGAA).

3 T MR perfusion of solid pancreatic lesions using dynamic contrast-enhanced DISCO sequence: Usefulness of qualitative and quantitative analyses in a pilot study

PurposeTo assess the usefulness of qualitative and quantitative analyses of pancreatic focal diseases by using the dynamic contrast-enhanced Differential Subsampling with Cartesian Ordering (DISCO) sequence at 3 T MR device. Materials and methodsTen patients without pancreatic diseases and twenty-five patients with pathologically confirmed pancreatic focal disease (ductal adenocarcinoma, n = 14; endocrine tumour, n = 8; focal chronic pancreatitis, n = 3), underwent MRI by 3 T-device. Multiphasic contrast-enhanced MR perfusion, consisting of a 3D axial navigator, based free-breathing T1-weighted DISCO sequence, was repeated for 5 min. A dose of 0.1 mL/kg of Gadobutrolo with a 20 mL saline flush was injected at a flow rate of 5 mL/s. Perfusion MRI were processed using a dedicated software package (GeniQ; GE Healthcare), obtaining both a time-signal-intensity curve (TSIC) and perfusion maps for each healthy pancreatic parenchyma and focal disease. The TSIC were grouped into four types according to their shapes and the MR perfusion parameters (Ktrans, Kep, Ve, IAUGC) were calculated.The one-way analysis of variance and the Student's t-test were used to correlate the quantitative and qualitative parameters with the tissue histology. ResultsAll 10 patients with healthy pancreas presented a TSIC-type 1; TSIC-type 2 was observed in all 14 ductal adenocarcinomas and in one neuroendocrine tumour; TSIC-type 3 was recognized in the remaining 7 neuroendocrine neoplasms; TSIC-type 4 was identified in all 3 focal chronic pancreatitis. All perfusion parameters were significantly different (p < 0.0001) for each type of lesion. Furthermore, Ve was also very useful to discriminate between normal and pathological tissues (p = 0.0005). ConclusionQualitative and quantitative analyses of contrast-enhanced 3 T MR perfusion, using the dynamic contrast-enhanced DISCO sequence, could be considered an interesting tool to improve the diagnosis of focal pancreatic diseases, of solid lesions in particular. Further investigations with prospective larger sample studies are required to confirm these preliminary results.

Comparison of Diagnostic Performance of Quantitative Flow Ratio in Patients With Versus Without Diabetes Mellitus

Quantitative flow ratio (QFR) is a novel technique to calculate fractional flow reserve (FFR), without hyperemia induction or a pressure wire, and has not yet been validated in patients with diabetes mellitus (DM), who are at increased risk of coronary microvascular dysfunction. The purpose of our study was to compare the diagnostic performance of QFR in diabetic and nondiabetic patients. Patients who underwent invasive coronary angiography and subsequent invasive FFR measurement within 6 months were included. QFR was determined in all coronary arteries in which invasive FFR was performed, using a dedicated software package. Diagnostic accuracy and the area under the receiver-operating characteristic curve (AUC) were determined for QFR, using an invasive FFR cut-off value of ≤0.80 as the reference standard. In total, 320 coronary arteries from 66 (25%) diabetic and 193 (75%) nondiabetic patients were analyzed. On a vessel-based analysis, diagnostic accuracy, sensitivity, and specificity showed no significant difference between diabetic and nondiabetic patients: 88% versus 85% (p = 0.47), 71% versus 69% (p = 0.72), and 95% versus 91% (p = 0.24). Moreover, the AUC was not significantly different between patients with and without DM, 0.91 versus 0.93 (p = 0.74). The per-vessel AUC was significantly higher for QFR compared with percent diameter stenosis in both diabetic and nondiabetic patients, 0.91 versus 0.76 (p <0.05) and 0.93 versus 0.77 (p <0.001), respectively. In conclusion, we showed a good diagnostic performance of QFR which was independent of the presence of DM.

Left atrial strain and distensibility in relation to left ventricular dysfunction and prognosis in aortic stenosis

To test the relationship between left atrial (LA) distensibility (LAD), LA strain (LAS), and left ventricular (LV) dysfunction and prognosis in aortic stenosis (AS). Transthoracic Doppler echocardiography was performed prospectively in 102 consecutive patients with AS (77 with severe, 25 with moderate, mean age 77years). LA volume was calculated by the area-length method in apical four- and two-chamber views, immediately before mitral valve opening (Volmax ) and at mitral valve closure (Volmin ). LAD was defined as (Volmax -Volmin )×100%/Volmin . LAS (mean of maximal strain from the 4-2 chamber views) was conducted using a dedicated software package. The endpoint was hospitalization for heart failure and death from any cause. Left atrial strain, LAD, and LA vol/m² were significantly correlated with LV diastolic parameters, and PASP (all, P<0.05). However, LAD and LAS but not LA vol/m² were significantly correlated with Charlson score, LV global longitudinal strain, and to transaortic mean gradient (all, P<0.05). At a median follow-up of 25months, 53 patients had an event. LAS, LAD, LA vol/m², and Charlson index were associated with events (all, P<0.05). In multivariate analysis, LAD, LAS, and Charlson index (all, P<0.01) remained independently associated with events. Using a ROC curve analysis, LAD≤69% and LAS≤17% were the best cutoffs associated with an event. In patients with moderate to severe AS, LAD and LAS are associated with LV dysfunction, AS severity, and are independently linked to events.

Nuclear Factor Kappa-B Is Enriched in Eyelid Specimens of Rosacea: Implications for Pathogenesis and Therapy

To assess the role of nuclear factor kappa-B (NFKB) in cutaneous specimens of rosacea and unaffected tissue. Immunohistochemical staining was performed for the activated, phosphorylated variant of NFKB (pNFKB) in eyelid specimens of rosacea (n=12) and normal, healthy tissue (n= 12). The numbers of positively staining cells/40× microscopic field were counted across 5 consecutive fields. Additionally, quantitative Western blotting was carried out for pNFKB and NFKB in specimens of rosacea (n= 15) and normal controls (n= 14). Statistical comparisons were performed via a dedicated software package. The mean number of cells/40× microscopic field that stained positively for pNFKB was 18.4 (standard deviation= 15.3) for control patients and 39.3 (standard deviation= 16.9) for rosacea patients, and the difference between the 2 groups was statistically significant (P= .0024). On Western blotting, the mean ratios of pNFKB:NFKB for control and rosacea patients measured 0.58 (standard deviation= 0.81) and 3.11 (standard deviation= 3.53), respectively. The 2 groups were statistically significantly different (P= .0002). The activated form of NFKB is enriched in rosacea, indicating a role for this pathway in the pathogenesis of this disease. Interference with NFKB signaling may represent a novel therapy for rosacea as clinical agentsbecome available. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Left atrial function is transiently impaired in tako-tsubo cardiomyopathy: A prospective study using left atrial two-dimensional longitudinal strain

Takotsubo cardiomyopathy (TTC) is a distinct clinical entity characterized by the presence of transient left ventricular (LV) wall motion abnormalities without significant culprit obstructive coronary artery disease. Whether left atrial (LA) function is also transiently impaired in this setting is unclear. To assess prospectively the LA function by two-dimensional longitudinal strain at the acute phase of TTC and after recovery. Thirty-seven consecutive patients satisfying the criteria for typical TTC (mean age 79 ± 9 years, 34 women) underwent transthoracic-Doppler echocardiography at the acute phase and at follow-up (on average 30 days later), including the measurement of the LA peak systolic longitudinal strain (LAS) which was measured as a mean of maximal strain from the 4–2 chamber views conducted using a dedicated software package, using R-R gating. A control group of 8 patients (76 ± 7 years, 7 women) without overt cardiovascular disease served as a comparative group. In the TTC group, LAS improved significantly between the two examinations from 15.5 ± 6% to 27 ± 9% ( P < 0.01) whereas LA volume did not change (from 30 ± 13 to 29 ± 12 ml/m 2 , P = NS). By comparison, in the control group LAS was 30 ± 3% ( P < 0.01 vs. TTC acute phase, P = NS vs. TTC follow-up) and LA volume/m 2 was 28 ± 3.5 ( P = NS vs. TTC all phases). The change of LAS in the TTC group (median improvement 62%, 25 th -75 th percentiles: 18–129%) was significantly correlated to the change of the global LV longitudinal strain ( r = −0.41, P = 0.01). Serial measurements of LAS suggests transient impairment of LA function (reservoir) at the acute phase of TTC. Furthermore, the improvement of LAS parallel the dynamic improvement of LV systolic function.

A novel software tool for semi-automatic quantification of thoracic aorta dilatation on baseline and follow-up computed tomography angiography

A dedicated software package that could semi-automatically assess differences in aortic maximal cross-sectional diameters from consecutive CT scans would most likely reduce the post-processing time and effort by the physicians. The aim of this study was to present and assess the quality of a new tool for the semi-automatic quantification of thoracic aorta dilation dimensions. Twenty-nine patients with two CTA scans of the thoracic aorta for which the official clinical report indicated an increase in aortic diameters were included in the study. Aortic maximal cross-sectional diameters of baseline and follow-up studies generated semi-automatically by the software were compared with corresponding manual measurements. The semi-automatic measurements were performed at seven landmarks defined on the baseline scan by two operators. Bias, Bland–Altman plots and intraclass correlation coefficients were calculated between the two methods and, for the semi-automatic software, also between two observers. The average time difference between the two scans of a single patient was 1188 ± 622 days. For the semi-automatic software, in 2 out of 29 patients, manual interaction was necessary; in the remaining 27 patients (93.1%), semi-automatic results were generated, demonstrating excellent intraclass correlation coefficients (all values ≥ 0.91) and small differences, especially for the proximal aortic arch (baseline: 0.19 ± 1.30 mm; follow-up: 0.44 ± 2.21 mm), the mid descending aorta (0.37 ± 1.64 mm; 0.37 ± 2.06 mm), and the diaphragm (0.30 ± 1.14 mm; 0.37 ± 1.80 mm). The inter-observer variability was low with all errors in diameters ≤ 1 mm, and intraclass correlation coefficients all ≥ 0.95. The semi-automatic tool decreased the processing time by 40% (13 vs. 22 min). In this work, a semi-automatic software package that allows the assessment of thoracic aorta diameters from baseline and follow-up CTs (and their differences), was presented, and demonstrated high accuracy and low inter-observer variability.

Quantitative Assessment of Dry Eye Parameters After Müller's Muscle-Conjunctival Resection.

Müller's muscle-conjunctival resection (MMCR) is a highly effective technique to correct upper eyelid ptosis. However, several authorities have raised concerns about the possibility of postoperative ocular surface dryness. This study was performed to assess the impact of MMCR on clinically meaningful parameters of the ocular surface. In adult patients, tear break-up time, lipid layer thickness, and osmolarity were measured via direct observation, interferometry, and impedance measurements before surgery and 3 months after surgery in patients who underwent MMCR. Statistical analysis was performed via a dedicated software package. Fifteen eyes of 14 patients were included in the study. Mean pre- and postoperative tear break-up times were 12.71 ± 2.20 and 12.43 ± 2.41 seconds, respectively (p = 0.1648). Preoperatively, the mean lipid layer thickness measurement was 91.00 ± 7.02 nm, whereas the mean postoperative value was 88.86 ± 21.36 nm (p = 0.6613). The mean preoperative tear osmolarity measured 291.4 ± 8.86 mOsm/l, and the mean postoperative measurement was 289.86 ± 9.74 mOsm/l (p = 0.2652). MMCR does not appear to change clinically meaningful ocular surface disease parameters, and postoperative dryness did not result from this procedure. In appropriately selected patients, MMCR can be safely performed without increased concerns regarding postoperative dry eye disease.

Left atrial strain and distensibility in relation to left ventricular dysfunction and prognosis in aortic stenosis

Left atrial (LA) function is increasingly used to assess cardiovascular diseases. We tested the relationship between LA distensibility (Lad), LA strain (Las) and left ventricular dysfunction and prognosis in aortic stenosis (AS). Transthoracic Doppler echocardiography was performed prospectively in 98 consecutive patients with AS (63 with severe, 35 with moderate AS, mean age 77 ± 10 years, 49% women, mean aortic valve area 0.5 ± 0.15 cm 2 , mean LVEF 63 ± 13%). LA volume was calculated by the area-length method in apical four-and two-chamber views, at two points: immediately before mitral valve opening (Vol max) and at mitral valve closure (Vol min). LA distensibility was defined as (Vol max − Vol min) × 100%/Vol min. Las (mean of maximal strain from the 4-2-3 chamber views) was conducted using a dedicated software package, using R-R gating. The end-point was hospitalisation for heart failure and death from any cause. Las, Lad, and LA vol/m 2 were significantly correlated to E/A, E/e’, and pulmonary artery systolic pressure (all, P < 0.05). However, Lad and Las but not LA vol/m 2 were significantly correlated to comorbidities index (Charlson, Euroscore), LVEF, stroke volume/m 2 , as well as to peak aortic jet velocity (all, P < 0.05). At a median follow-up of 25 months, 48 patients had an event. Las, Lad, LA volume/m 2 , as well as Charlson index, diabetes, and DTI parameters were associated to events (all, P < 0.05). In multivariate analysis, Lad, Las, (all, P < 0.01) and Charlson index ( P < 0.05) remained independently associated to events. Using a ROC curve analysis, a LAd < 70% (AUC = 0. 76 ± 0.05, P < 0.001), and Las < 17% (AUC = 0.73 ± 0.05) were the best cut-off to predict an event at follow-up. In patients with moderate to severe AS, Lad and LAs are associated with LV diastolic and systolic dysfunction, AS severity, and are independently linked to events.

Spatio-Temporal Areal Unit Modeling in R with Conditional Autoregressive Priors Using the CARBayesST Package

Spatial data relating to non-overlapping areal units are prevalent in fields such as economics, environmental science, epidemiology and social science, and a large suite of modeling tools have been developed for analysing these data. Many utilize conditional autoregressive (CAR) priors to capture the spatial autocorrelation inherent in these data, and software packages such as CARBayes and R-INLA have been developed to make these models easily accessible to others. Such spatial data are typically available for multiple time periods, and the development of methodology for capturing temporally changing spatial dynamics is the focus of much current research. A sizeable proportion of this literature has focused on extending CAR priors to the spatio-temporal domain, and this article presents the R package CARBayesST, which is the first dedicated software package for spatio-temporal areal unit modeling with conditional autoregressive priors. The software package allows to fit a range of models focused on different aspects of spacetime modeling, including estimation of overall space and time trends, and the identification of clusters of areal units that exhibit elevated values. This paper outlines the class of models that the software package implement, before applying them to simulated and two real examples from the fields of epidemiology and housing market analysis.

Relation entre le strain de l’oreillette gauche, la dysfonction ventriculaire gauche et le pronostic dans le rétrécissement aortique

Background Left atrial (LA) function is increasingly used to predict cardiovascular events. Objective We tested the relationship between LA strain (Las) and left ventricular dysfunction and prognosis in aortic stenosis (AS). Methods Transthoracic Doppler echocardiography was performed prospectively in 98 consecutive patients with AS (63 with severe, 35 with moderate AS, mean age 77 ± 10 years, 49% women, mean aortic valve area 0.5 ± 0.15 cm2, mean LVEF 63 ± 13%). LA volume was calculated by the area-length method in apical four-and two-chamber views and indexed to body surface area. Las (mean of maximal strain from the 4-2-3 chamber views) was conducted using a dedicated software package, using R-R gating. The end-point was hospitalization for heart failure and death from any cause. Results Las, and LA volume/mLas were significantly correlated to E/A, E/e’, and pulmonary artery systolic pressure (all, P Conclusion In patients with moderate to severe AS, Las is associated with LV diastolic and systolic dysfunction, AS severity, and is independently linked to events.

A method and tool for combining differential or inclusive measurements obtained with simultaneously constrained uncertainties

A method is discussed that allows combining sets of differential or inclusive measurements. It is assumed that at least one measurement was obtained with simultaneously fitting a set of nuisance parameters, representing sources of systematic uncertainties. As a result of beneficial constraints from the data all such fitted parameters are correlated among each other. The best approach for a combination of these measurements would be the maximization of a combined likelihood, for which the full fit model of each measurement and the original data are required. However, only in rare cases this information is publicly available. In absence of this information most commonly used combination methods are not able to account for these correlations between uncertainties, which can lead to severe biases as shown in this article. The method discussed here provides a solution for this problem. It relies on the public result and its covariance or Hessian, only, and is validated against the combined-likelihood approach. A dedicated software package implementing this method is also presented. It provides a text-based user interface alongside a C++ interface. The latter also interfaces to ROOT classes for simple combination of binned measurements such as differential cross sections.

Association of the Active and Passive Components of Left Atrial Deformation with Left Ventricular Function

Left atrial (LA) strain imaging enables the quantitative assessment of LA function. The clinical relevance of these measurements is dependent on the provision of information incremental to the left ventricular (LV) evaluation. The aim of this study was to test the hypothesis that LA pump function but not reservoir function is independent of measurement of LV mechanics. Echocardiography was undertaken in a community-based study of 576 participants ≥65years of age with one or more risk factors (e.g., hypertension, diabetes mellitus, obesity). Strain analysis was conducted using a dedicated software package, using R-R gating. LV function was classified as normal in the presence of global longitudinal strain (GLS) (≤-18%) or global circumferential strain (GCS) (≤-22%). The associations between GLS or GCS and LA reservoir, conduit, and pump strain were assessed using univariate and multivariate linear regression. Patients (mean age 71±5years, 54% women) with reduced GLS had higher blood pressure and rates of diabetes and obesity (P<.05). LA reservoir strain and conduit strain were lower in the group with impaired GLS (38.2±7.3% vs 39.9±6.4% [P=.004] and 18.7±5.7% vs 20.5±5.1% [P<.001], respectively), but there was no difference in LA pump strain (19.5±5.5% vs 19.3±4.6%, P=.72). GLS was independently associated with LA reservoir and conduit strain (P<.05) but not independently associated with LA pump strain (P=.91). Reduced GCS was associated with a larger body mass index, male sex, and diabetes (P<.05). There were no differences in LA reservoir, conduit, and pump strain in patients with normal and abnormal GCS (P>.05). The application of LA strain is specific to the component measured. LA pump strain is independent of LV mechanics.

Sludge accumulation and distribution impact the hydraulic performance in waste stabilisation ponds

Waste stabilisation ponds (WSPs) are used worldwide for wastewater treatment, and throughout their operation require periodic sludge surveys. Sludge accumulation in WSPs can impact performance by reducing the effective volume of the pond, and altering the pond hydraulics and wastewater treatment efficiency. Traditionally, sludge heights, and thus sludge volume, have been measured using low-resolution and labour intensive methods such as ‘sludge judge’ and the ‘white towel test’. A sonar device, a readily available technology, fitted to a remotely operated vehicle (ROV) was shown to improve the spatial resolution and accuracy of sludge height measurements, as well as reduce labour and safety requirements. Coupled with a dedicated software package, the profiling of several WSPs has shown that the ROV with autonomous sonar device is capable of providing sludge bathymetry with greatly increased spatial resolution in a greatly reduced profiling time, leading to a better understanding of the role played by sludge accumulation in hydraulic performance of WSPs. The high-resolution bathymetry collected was used to support a much more detailed hydrodynamic assessment of systems with low, medium and high accumulations of sludge. The results of the modelling show that hydraulic performance is not only influenced by the sludge accumulation, but also that the spatial distribution of sludge plays a critical role in reducing the treatment capacity of these systems. In a range of ponds modelled, the reduction in residence time ranged from 33% in a pond with a uniform sludge distribution to a reduction of up to 60% in a pond with highly channelized flow. The combination of high-resolution measurement of sludge accumulation and hydrodynamic modelling will help in the development of frameworks for wastewater sludge management, including the development of more reliable computer models, and could potentially have wider application in the monitoring of other small to medium water bodies, such as channels, recreational water bodies, and commercial ports.