Low Fraction Research Articles

Atrial Fibrillation Surgery in Australia: Are We Doing Enough?

This study aimed to examine contemporary burden and treatment trends of atrial fibrillation (AF) in patients undergoing cardiac surgery in Australia and New Zealand. This allows comparison of contemporary practice with the Society of Thoracic Surgeons guideline recommendations for the surgical treatment of AF in patients undergoing cardiac surgery. A 10-year retrospective review of the Australian & New Zealand Society of Cardiac & Thoracic Surgeons National Cardiac Surgery Database was performed, examining all adult cardiac surgery patients from 2011 to 2021. Patients were grouped by the presence or absence of AF, and simple descriptive statistical analysis was performed to assess baseline demographics and premorbid condition of the patients. The incidence of AF was analysed by type of surgery. Trends for surgical treatment of AF were then analysed using simple descriptive statistics, examining isolated left atrial appendage ligation, isolated surgical ablation, and combined ligation and ablation. In the last 10 years, the Australian & New Zealand Society of Cardiac & Thoracic Surgeons database has recorded 140,680 patients who underwent cardiac surgery. Atrial fibrillation (AF) was present in 21,077 patients (14%). Patients with AF were generally older (72.25 vs 66.65 years; p<0.001). Among patients undergoing cardiac surgery, AF was more common in female than in male patients (18% vs 13%, respectively). Patients with AF more often had a higher classification of dyspnoea according to the New York Heart Association and lower ejection fractions compared with their AF-free counterparts. The incidence of AF as a comorbid condition was more frequent in patients undergoing mitral valve surgery or combined coronary artery bypass grafting and valve surgery (aortic, mitral, or both) compared with those undergoing isolated coronary or aortic surgery. Only 11.90% (n=2,509) of patients with AF received a combined ablation and left atrial appendage ligation, and 19.54% (n=693) of those received a Cox-Maze IV ablation. The burden of concomitant AF in patients undergoing cardiac surgery in Australia is higher than previously reported (14% vs 5%-11%). Despite strong recommendation for the surgical management of AF in patients undergoing cardiac surgery and clear evidence of its benefit, both left atrial appendage ligation and surgical ablation independently or concomitantly remain heavily underutilised in this cohort.

Predictive value of the left atrioventricular coupling index for recurrence after radiofrequency ablation of paroxysmal atrial fibrillation

BackgroundAlthough patients with paroxysmal atrial fibrillation (PAF) are preferred to undergo catheter ablation (CA), the high possibility of recurrence following surgery is still concerning. We aimed to evaluate the ability of the left atrioventricular coupling index (LACI), which is the ratio of the left atrium end-diastolic volume to the left ventricle end-diastolic volume, to predict PAF recurrence after CA.MethodsPatients with PAF undergoing CA for the first time between January 2018 and June 2021 were admitted and grouped by recurrence within a year. LACI was measured before CA using ultrasonography. Risk factors identified by multivariable logistic regression analysis, and the area under the receiver operating characteristic (ROC) curve was used to assess the ability of LACI to predict PAF recurrence after CAP.ResultsAmong the 204 patients treated at our hospital, 164 patients were included in the research after eliminating those who were lost to follow-up. Among them, 56 individuals had recurrence following a 90-day blanking period. Recurrence is more likely in elderly patients with high blood pressure. Patients who suffered recurrence exhibited lower left atrial ejection fraction and increased LACI, left atrial volume minimum, and left atrium volume index maximum. LACI was an independent risk factor for postoperative recurrence (OR: 1.526, 95% CI: 1.325–1.757, P < 0.001), and ROC displayed remarkable predictive value [area under the curve (AUC) = 0.868].ConclusionsHigh LACI is significantly associated with postoperative recurrence in PAF patients, and LACI has incremental prognostic value to predict recurrence.

Experimental investigation of heat transfer enhancement, thermal efficiency, and pressure drop in forced convection of magnetic hybrid nanofluid (Fe₃O₄/TiO₂) under varied magnetic field strengths and waveforms

Applying a magnetic field to influence convective flow of ferrofluids has become an efficient method for enhancing heat transfer in thermal systems, particularly in straight tubes. This study investigates the heat transfer properties of Fe₃O₄/TiO₂ nanofluids within a heated copper tube under varied magnetic field strengths and waveforms. Optimal magnetic field conditions were determined at 4 V and 60 Hz across all waveform types, as higher frequencies and voltages increased magnetic field intensity, thereby reducing heat transfer rates. Magnetic waveforms exerted differential influences on pressure drop, indicating varied nanoparticle alignment and turbulence levels, impacting fluid flow dynamics and viscosity. Higher nanoparticle concentration (0.1% vol) correlated with increased pressure drops across sine, square, and triangular waveforms, suggesting heightened flow resistance and potential nanoparticle agglomeration, thus reducing thermal efficiency. Conversely, lower concentrations exhibited enhanced thermal performance due to improved nanoparticle dispersion and reduced thermal resistance. At 0.1% vol, heat transfer enhancement without a magnetic field was 16.5%. The introduction of magnetic field waveforms attenuated this enhancement: 15.3% (sine), 13.26% (square), and 12.59% (triangular). Conversely, at lower volume fractions, heat transfer enhancements with magnetic fields exceeded those without at 0.05% vol, enhancements were 20.92% (sine), 21.3% (square), and 21.34% (triangular); at 0.025% vol, enhancements were 22.07% (sine), 22.3% (square), and 21.32% (triangular); at 0.0125% vol, enhancements were 27.87% (sine), 28.21% (square), and 26.74% (triangular); and at 0.0065% vol, enhancements were 22.24% (sine), 22.3% (square), and 24.49% (triangular).

Atrial fibrillation in transthyretin amyloidotic cardiomyopathy: prevalence and echocardiographic predictors.

Conduction disorders and arrhythmias frequently accompany cardiac amyloidosis (CA), with atrial fibrillation (AF) being the most prevalent manifestation. The prevalence of AF varies across different types of CA, with transthyretin (TTR) type showing the highest prevalence upon diagnosis. A retrospective, observational analysis was conducted to evaluate the prevalence of AF and to identify echocardiographic predictors related to the development of AF in our population of patients with transthyretin cardiac amyloidosis (TTR-CA). A total of 99 patients with TTR-CA were identified, with a median age of 82 (75-85) years, a median ejection fraction of 50% (43-60) and 97 of them wild type. At the time of cardiomyopathy diagnosis, 55% had AF, and during follow-up, 43% developed new AF. Among the latter group, there was a non-significant tendency to have a smaller diastolic diameter, lower left ventricular ejection fraction, increased septal thickness, higher pulmonary pressure, and lower tissue velocities, with statistical significance only found in the right ventricular S wave velocity: 8.5 cm/s (7.7-9) vs. 9.7 cm/s (8.4-10) (P=0.046). The high prevalence and incidence of AF in TTR-CA is demonstrated in our series. Doppler echocardiography might help to identify patients with signs of more advanced cardiomyopathy, such as lower right ventricle tissue velocity, who might be at higher risk of developing AF and gain the benefit of prompt diagnosis and treatment.

The Utility of Speckle Tracking Echocardiographic Parameters in Predicting Atrial Fibrillation Recurrence After Catheter Ablation in Patients with Non-Valvular Atrial Fibrillation.

Despite the efficacy of catheter ablation (CA) as a treatment for non-valvular atrial fibrillation (NVAF), many patients still experience atrial fibrillation (AF) recurrence after CA. This study aimed to evaluate the predictive value of speckle tracking echocardiographic (STE) parameters for AF recurrence post-ablation. A total of 380 NVAF patients treated with CA at the First Affiliated Hospital of Guangxi Medical University from January 2020 to March 2023 were prospectively recruited. The mean age was 59.4 ± 10.8 years, and 72.1% were male, including 150 patients (39.5%) with persistent AF and 230 patients (60.5%) with paroxysmal AF. STE was used to evaluate baseline left atrial (LA) function before CA within 48h. Over a median follow-up of 9 (interquartile range, 4-17) months, AF recurrence occurred in 132 patients (34.7%). The recurrence group showed lower left ventricular ejection fraction, LA reservoir strain (LASr), and conduit strain (LAScd), but higher LA stiffness than non- recurrence group (all P < 0.05). Multivariable Cox regression identified LA stiffness and LASr as independent risk factors. Time-dependent ROC analysis showed that LA stiffness (AUC 0.768, 95% CI 0.705-0.831) and LASr (AUC 0.755, 95% CI 0.691-0.820) were better at predicting 1-year AF recurrence than other risk factors. For 2-year AF recurrence post-catheter ablation, LA stiffness (AUC 0.866, 95% CI 0.804-0.928) and LASr (AUC 0.860, 95% CI 0.800-0.920) also demonstrated superior predictive performance. Kaplan-Meier curves showed a significant difference in AF recurrence rate for patients with LA stiffness > 0.55 and LASr ≤ 24.3% (Log rank P < 0.01). Evaluation of LA function using STE assists in stratifying the risk of AF recurrence in NVAF patients and guiding follow-up management. LASr and LA stiffness are independent predictors of AF recurrence following CA in NVAF patients, and potentially outperforming other morphological parameters.

Automatic Echocardiographic Assessment of Left Atrial Function for Prediction of Low-Voltage Areas in Non-Valvular Atrial Fibrillation.

Left atrial low-voltage areas (LA-LVAs) identified by 3D-electroanatomical mapping are crucial for determining treatment strategies and prognosis in patients with atrial fibrillation (AF). However, convenient and accurate prediction of LA-LVAs remains challenging. This study aimed to assess the viability of utilizing automatically obtained echocardiographic parameters to predict the presence of LA-LVAs in patients with non-valvular atrial fibrillation (NVAF). This retrospective study included 190 NVAF patients who underwent initial catheter ablation. Before ablation, echocardiographic data were obtained, left atrial volume and strain were automatically calculated using advanced software (Dynamic-HeartModel and AutoStrain). Electroanatomic mapping (EAM) was also performed. Results were compared between patients with LA-LVAs ≥5% (LVAs group) and <5% (non-LVAs group). LA-LVAs were observed in 81 patients (42.6%), with a significantly higher incidence in those with persistent AF than paroxysmal AF (55.6% vs 19.3%, P <0.001). Compared with the non-LVAs group, the LVAs group included significantly older patients, lower left ventricular ejection fraction, higher heart rate, and higher E/e' ratio (P <0.05). The LVAs group exhibited higher left atrial volumemax index (LAVimax) and lower left atrial reservoir strain (LASr) (P <0.001). In multivariate analysis, both LAVimax and LASr emerged as independent indicators of LVAs (OR 0.85; 95% CI 0.80-0.90, P<0.001) and (OR 1.15, 95% CI 1.02-1.29, P =0.021). ROC analysis demonstrated good predictive capacity for LA-LVAs, with an AUC of 0.733 (95% CI 0.650-0.794, P <0.001) for LAVimax and 0.839 (95% CI 0.779-0.898, P <0.001) for LASr. Automatic assessment of LAVimax and LASr presents a promising non-invasive modality for predicting the presence of LA-LVAs and evaluating significant atrial remodeling in NVAF patients. This approach holds potential for aiding in risk stratification and treatment decision-making, ultimately improving clinical outcomes in patients.

Deposit of Red Blood Cells at low concentrations in evaporating droplets is dominated by a central edge growth

Evaporation of blood droplets and diluted blood samples is a topic of intensive research, as it is considered a potential low-cost diagnostic tool. So far, samples with a volume fraction down to a few percent of red blood cells have been studied, and these were reportedly dominated by a “coffee-ring” deposit. In this study, samples with lower volume fractions were used to investigate the growth of the evaporative deposit from sessile droplets in more detail. We observed that blood samples and salt solutions with less than 1% volume fraction of red blood cells are dominated by a central deposit. We characterized the growth process of this central deposit by evaporating elongated drops and determined that it is consistent with the Kardar-Parisi-Zhang process in the presence of quenched disorder. Our results showed a sensitivity of the deposit size to fibrinogen concentration and the shape of red blood cells, suggesting that this parameter could be developed into a new and cost-effective clinical marker for inflammation and red blood cell deformation.

Differential modulation of photosystem II photochemical efficiency in six C4 xero-halophytes.

Xero-halophytes are the salt-tolerant plants of dry habitats that adapt efficient strategies to endure extreme salt and water fluctuations. This study elucidated the adaptations related to PSII photochemistry, photoprotection, and photoinhibition in six C4 xero-halophytes (Atriplex stocksii , Haloxylon stocksii , Salsola imbricata, Suaeda fruticosa, Desmostachya bipinnata , and Saccharum griffithii ) grown in their native habitats. Chlorophyll a fluorescence quenching measurements suggested that S. imbricata and H. stocksii maintained efficient PSII photochemistry by downregulating heat dissipation and keeping a high fraction of open PSII centres that indicates plastoquinone (PQ) pool oxidation. Fluorescence induction kinetics revealed that S. imbricata demonstrated the highest performance index of PSII excitation to the reduction of end electron acceptors. S. fruticosa sustained photochemical efficiency through enhanced dissipation of excess energy and a low fraction of open PSII centres, indicating PQ reduced state. The large light-harvesting antenna size, deduced from the chlorophyll a /b ratio in S. fruticosa apparently led to the superior performance index of PSII excitation to the reduction of intersystem electron carriers. A. stocksii retained more open PSII centres with responsive non-photochemical quenching to safely dissipate excess energy. Despite maintaining the highest pigment contents and stoichiometry, A. stocksii remained lowest in both performance indices. The grass species D. bipinnata and S. griffithii kept fewer PSII centres open during photoinhibition, as evidenced by downregulation of PSII operating efficiency. The results provide insights into the differential modulation of PSII photochemical efficiency through dynamic control of photoprotective energy dissipation, PQ pool redox states, and photoinhibitory shutdown in these xero-halophytes.

Nanotechnology enabled casting of aluminum alloy 7075 turbines

Aluminum alloy 7075 is well-known for its high-performance structural systems due to its lightweight and excellent mechanical properties. However, its susceptibility to hot cracking and limited fluidity hinder its casting suitability, posing challenges in manufacturing near-net-shaped structures economically, especially for thin and intricate aerospace components. This paper presents experimental results based on nano-treating, an emerging nanotechnology-enabled manufacturing method by incorporating a low fraction of nanoparticles in liquid aluminum, to allow the casting of complex aluminum alloy 7075 parts. Vacuum fluidity tests demonstrated that nano-treating of aluminum alloy 7075 with only 0.5 vol% TiC nanoparticles increased the fluidity of aluminum alloy 7075 by more than 20%, effectively eliminating hot cracking and enhancing surface quality. Through the Rapid Investment Casting process, nano-treated aluminum alloy 7075 can be successfully cast into turbines with 0.5 mm thick blades. In contrast, aluminum alloy 7075 without nano-treating failed to produce good casting quality due to poor filling and severe cracks. The manufacturing trials highlight the significant improvement in castability achieved through nano-treating, opening a novel pathway for the cost-effective production of complex aluminum alloy 7075 structures for numerous applications.

Cardiovascular Risk Factors Associated with Mitral Annular Calcification in a Non-Rheumatic Population

Mitral Annular Calcification (MAC), cardiovascular disease marker was common in non-rheumatic populations but was frequently disregarded in clinical evaluations. Objective: To MAC and to assess effect of these factors on cardiac function in non-rheumatic adult population. Methods: From September 2022 to August 2023, we conducted this cross-sectional study at Cardiac Center, Pakistan institute of medical sciences Islamabad that included 182 adults aged 50 years and older. We evaluated the patient's clinical history, demographic data and echocardiographic and laboratory results. The association between the presence of MAC and cardiovascular risk factors (age, hypertension, diabetes, dyslipidemia, smoking, obesity and chronic renal disease) was analyzed using logistic regression. Echocardiographic data were used to provide insight into cardiac function. Results: The prevalence of MAC was substantially correlated with hypertension (OR = 2.30), diabetes (OR = 2.00), dyslipidemia (OR = 1.75) and obesity (OR = 1.07). Also, smoking demonstrated a significant correlation with MAC. In comparison to those without MAC, individuals with MAC exhibited substantially lower ejection fractions, increased left atrial diameters and impaired diastolic function, as indicated by cardiac function assessments. Conclusion: In non-rheumatic population, MAC was significantly associated with conventional cardiovascular risk factors, particularly hypertension and diabetes.

Atrial fibrillation versus non-atrial fibrillation coronary embolism.

Coronary embolism (CE) is an uncommon cause of non-atherosclerotic acute myocardial infarction (AMI). Although atrial fibrillation (AF) is the main cause of CE, evidence of clinical, biochemical, echocardiographic, angiographic findings and outcomes of AF CE is lacking. We retrospectively analyzed 85 consecutive patients with CE that was diagnosed based on criteria encompassing clinical, angiographic and diagnostic imaging findings. We classified patients according to AF CE or non-AF CE. Forty-five patients presented with AF CE (53%). Patients with AF CE were older (76 ± 12 vs. 63 ± 14 years; p < 0.001) and had more often chronic kidney disease (24% vs. 5%; p = 0.01). AF CE had lower estimated glomerular filtration rate at admission (59 ± 18 vs. 77 ± 16 ml/min/1.73 m2; p < 0.001) and higher brain natriuretic peptide levels (512 ± 417 vs. 210 ± 479 pg/ml; p = 0.02). Coronary arteriography revealed a higher incidence of coronary artery obstruction in the AF CE group (73% vs. 38%; p = 0.001) without differences in interventional management. The AF CE group showed higher left atrial volume index (LAVI) (42 ± 15 vs. 25 ± 12 ml/m2; p < 0.001) and showed lower left atrium ejection fraction (LAEF) (32 ± 17 vs. 49 ± 17%; p = 0.001). In the multivariable analysis AF CE (OR 10 [95% CI 1.04-95; p = 0.046]) and LAEF (OR 0.94 [95% CI 0.88-0.99; p = 0.02]) were associated with worse in-hospital outcomes. Moreover, in the multivariable analysis, prior stroke (OR 12.5 [95% CI 1.1-137; p = 0.04]) and LAVI (OR 1.1 [95% CI 1.03-1.14; p = 0.003]) were independently associated with worse long-term outcomes. AF CE has specific characteristics compared to non-AF-CE and it is associated with more in-hospital events. Furthermore, atrial cardiopathy is associated with worse in-hospital and long-term outcomes in this setting.

An atomically controlled insulator-to-metal transition in iridate/manganite heterostructures.

All-insulator heterostructures with an emerging metallicity are at the forefront of material science, which typically contain at least one band insulator while it is not necessary to be. Here we show emergent phenomena in a series of all-correlated-insulator heterostructures that composed of insulating CaIrO3 and insulating La0.67Sr0.33MnO3. We observed an intriguing insulator-to-metal transition, that depends delicately on the thickness of the iridate component. The simultaneous enhancements of magnetization, electric conductivity, and magnetoresistance effect indicate a percolation-type nature of the insulator-to-metal transition, with the percolation threshold can be reached at an exceptionally low volume fraction of the iridate. Such a drastic transition is induced by an interfacial charge transfer, which interestingly alters the electronic and crystalline structures of the bulk region rather than the limited ultrathin interface. We further showcased the central role of effective correlation in modulating the insulator-to-metal transition, by demonstrating that the critical thickness of iridate for triggering the metallic state can be systematically reduced down to a single unit-cell layer.

In-depth analysis of natural organic matter fractions in drinking water treatment performance: Fate and role of humic substances in trihalomethanes formation potential

In this study we investigate the compositional changes in dissolved organic matter (DOM) fractions across diverse water sources and treatment processes in three Drinking Water Treatment Plants (DWTPs). High-Performance Size Exclusion Chromatography coupled with Diode Array Detection and Organic Carbon Detection (HPSEC-DAD-OCD) was employed to characterize DOM fractions, offering insights into treatment optimization. We examine bulk water parameters, DOM distributions, and the efficiency of treatment trains in reducing DOM fractions. Results reveal distinct DOM composition profiles in river-sourced versus reservoir-sourced waters, with implications for treatment processes. Coagulation, Granular Activated Carbon (GAC) adsorption, Electrodialysis Reversal (EDR), and Ion Exchange (IEX) were evaluated for their efficacy in removing DOM fractions. The analysis highlights the effectiveness of coagulation in reducing high molecular weight (MW) fractions, while GAC filtration targets lower MW fractions. EDR shows significant removal of anions and aromatics, while IEX demonstrates high removal efficiencies for removing humic substances (HS) fractions. Spectroscopic analysis further elucidates changes HS sub-fractions and their role in disinfection by-products (DBP) formation. To quantitatively assess the relationship between HS sub-fractions and trihalomethane formation potentials (THMFP), Pearson correlation analysis were conducted, unveiling robust associations between HS sub-fractions and THM-FP that can be predicted by surrogate parameters such as A254.

Influence of microstructural and loading direction on the ductility and anisotropy of Ni-based superalloys

The influences of phase coarsening and loading direction on the ductility of Ni-based superalloys with phase coarsening are investigated, and the relationship between their microstructural and macroscopic mechanical properties is also explored in detail. It is found that the precipitation phase and the corresponding phase coarsening significantly influence the ductility of alloys. Furthermore, anisotropic features in ductility are observed after phase coarsening. Generally, as the volume fraction of precipitation particles or the degree of phase coarsening increases, the ductility of alloys gradually decreases; and it initially increases and then decreases gradually with the increase of loading angle, presenting an inverted ‘V’ shape. Comparatively, for the alloys with lower volume fraction of precipitation particles and higher degree of phase coarsening, the ductility shows different variation trends with the degree of phase coarsening and loading angle compared with that in materials with other microstructure features, taking the minimum value at the loading angle of 45°. The variations of ductility are closely connected to the characteristics of precipitate shape, size and distribution. The microstructure evolution and the loading direction significantly affect the initiation and movement of dislocations within the material, and result in various macroscopic ductility characteristics in the Ni-based superalloys.

Effect of low molecular weight phenols on the in-mouth sensory perception of high molecular weight phenols by analyzing reconstituted wines

This research aimed to assess the contribution of monomeric phenols to the perception of bitterness and astringency by means of wine reconstitution experiments. Six wines with distinct total polyphenol indexes were selected and fractioned by preparative liquid chromatography into two fractions. Thirty-one reconstituted wines were prepared by combining distinct low molecular weight fractions (L) with different high molecular weight fractions (H). In-mouth attributes of reconstituted and reference wines were described by a trained sensory panel. Fractions were chemically characterized by UPLC-MS. No significant differences among sensory results were found between reference and reconstituted wines. Bitterness and astringency perception were strongly influenced by total proanthocyanidins content. Flavan-3-ol monomers and dimers were only responsible for astringency in wines with a low content of proanthocyanidins, as was the case in rosé wine. Quercetin-3-O-glucuronide and several anthocyanins presented correlations with bitterness in the reconstituted wines; notwithstanding, several interactions with this attribute were observed.

Clinical Effectiveness of Biological Immunomodulators in SARS-CoV-2-Associated Multisystem Inflammatory Syndrome in Children: A Systematic Review.

Although there is consensus to use immunoglobulins and corticosteroids as first-line treatments for multisystem inflammatory syndrome in children (MIS-C), the effectiveness of biological immunomodulators in patients refractory to standard therapy remains unclear. We aimed to outline real-world data on biological immunomodulators. A literature search using Ovid-Medline, EMBASE, Cochrane CDSR, and KMBASE was conducted from September 2021 to August 2022; certainty of evidence was assessed via GRADE. Among 258 studies, 10 were selected for analysis, of which 2 were observational studies (with control groups receiving standard therapy of either intravenous immunoglobulins and/or glucocorticoids) and 8 were single-arm studies. In all, 145 patients were treated with biological immunomodulators (anakinra (72; 49%) or infliximab (65; 44%)). In the first observational study, patients in the anakinra group initially exhibited a lower left ventricular ejection fraction than those in the control group. In the second study, patients in the infliximab group required less additional therapy and showed lower newly developed left ventricular dysfunction rate and reduced C-reactive protein levels. The clinical outcomes associated with each biological agent in single-arm studies were not reported individually. Biological immunomodulators are feasible therapeutic options for refractory MIS-C. Nevertheless, further research is warranted to demonstrate clinical efficacy.

Comparative Analysis of Basal vs. Apical Left Ventricular Aneurysms: Impact on Ejection Fraction and Cardiac Function.

Background and Objectives: Left ventricular aneurysm (LVA) is associated with a decline in cardiac function, evidenced by a lower ejection fraction (EF), due to the reduction in the proportion of functional myocardium. The left ventricular end-diastolic volume (LVEDV), the left ventricular aneurysm volume (LVAV), and the LVAV/LVEDV ratio show a strong correlation with the EF. The aim of this study was to determine LVA characteristics post-myocardial infarction (basal vs. apical) and to evaluate the impact of aneurysm volume in diastole (LVAVd), aneurysm area in diastole (LVAAd), and their respective ratios with LVEDV and area (LVEDA) on the EF, in order to identify the most critical predictive factors for assessing and managing the negative impact of aneurysms on cardiac function. Materials and Methods: This observational study included post-infarction LVA patients at the "Dedinje" Cardiovascular Institute in Belgrade, Serbia, undergoing routine transthoracic echocardiography. Echocardiography assessed volumes (LVEDV, LVESV, LVAVd, LVAVs) and areas (LVAAd, LVAAs, LVEDA, LVESA) using the area-length method. The ratios (LVAVd/LVEDV, LVAVs/LVESV, LVAAd/LVEDA, LVAAs/LVESA) were derived from these measures. The left ventricular EF was calculated using Simpson's method. Results: Basal aneurysms showed a significantly smaller LVAVd (p = 0.016), LVAAd (p = 0.003), and LVAAs (p = 0.029) compared to apical aneurysms, indicating that basal aneurysms are smaller in size. However, there was no significant difference in the EF and overall LV volumes between the groups, although the basal aneurysm group had a slightly higher EF and end-diastolic volume, with a slightly lower end-systolic volume. Furthermore, when comparing the correlation between the EF and the LVAVd, the LVEDV, and the LVAVd/LVEDV ratio, the results indicate that the LVAVd had the greatest impact on the EF (-0.695), followed by the LVAVd/LVEDV ratio (-0.637), and the lowest correlation is between the EF and LVEDV. A similar relationship is observed when comparing the EF with the LVESV, the LVAVs, and the LVAVs/LVESV ratio. Conclusions: Basal aneurysms are significantly smaller than apical ones, yet EF and LV volumes remain similar between the groups, with the EF being slightly higher in the basal group. In cases of LVA, LVAVd shows the strongest negative correlation with the EF, indicating its significant impact on systolic function, followed by the LVAVd/LVEDV ratio, with the weakest correlation seen between the EF and LVEDV.

Effect of surface orientation on the corrosion behavior of Ni-based single-crystal alloy in a simulated marine atmosphere at 750 °C

DD5 single-crystal alloy samples with different surface orientations were obtained by machining the alloy ingot perpendicular (PP) and parallel (P), respectively, to its solidification direction (SD). The corrosion behaviors of the PPSD and PSD alloy samples were investigated in the atmosphere of moist air + NaCl aerosol at 750 °C. Results showed that during initial corrosion, γ′ phase developed a thin NiO layer with Al internal corrosion product. However, a NiO nodule with an internal Cr2O3 layer was formed on γ phase. As corrosion progressed, the corrosion product gradually grew to a NiO/(Al, Cr)2O3 bilayer, accompanied by internal corrosion consisting of Al2O3. It was also found that the PSD sample with a lower fraction and smaller size of γ’ phases exhibited better corrosion resistance than the PPSD sample. The effect of alloy surface orientation on the corrosion mechanism was discussed.

Myocardial Scarring and Sudden Cardiac Death in Young Patients With Hypertrophic Cardiomyopathy

The ability to predict sudden cardiac death (SCD) in children and adolescents with hypertrophic cardiomyopathy (HCM) is currently inadequate. Late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) imaging is associated with SCD events in adults with HCM. To examine the prognostic significance of LGE in patients with HCM who are younger than 21 years. This multicenter, retrospective cohort study was conducted from April 8, 2015, to September 12, 2022, in patients with HCM who were younger than 21 years and had undergone CMR imaging across multiple sites in the US, Europe, and South America. Observers of CMR studies were masked toward outcomes and demographic characteristics. Natural history of HCM. The primary outcome was SCD and surrogate events, including resuscitated cardiac arrest and appropriate discharges from an implantable defibrillator. Continuous and categorical data are expressed as mean (SD), median (IQR), or number (percentage), respectively. Survivor curves comparing patients with and without LGE were constructed by the Kaplan-Meier method, and likelihood of subsequent clinical events was further evaluated using univariate and multivariable Cox proportional hazards models. Among 700 patients from 37 international centers, median (IQR) age was 14.8 (11.9-17.4) years, and 518 participants (74.0%) were male. During a median (IQR) [range] follow-up period of 1.9 (0.5-4.1) [0.1-14.8] years, 35 patients (5.0%) experienced SCD or equivalent events. LGE was present in 230 patients (32.9%), which constituted an mean (SD) burden of 5.9% (7.3%) of left ventricular myocardium. The LGE amount was higher in older patients and those with greater left ventricular mass and maximal wall thickness; patients with LGE had lower left ventricular ejection fractions and larger left atrial diameters. The presence and burden of LGE was associated with SCD, even after correcting for existing risk stratification tools. Patients with 10% or more LGE, relative to total myocardium, had a higher risk of SCD (unadjusted hazard ratio [HR], 2.19; 95% CI, 1.59-3.02; P < .001). Furthermore, the addition of LGE burden improved the performance of the HCM Risk-Kids score (before LGE addition: 0.66; 95% CI, 0.58-0.75; after LGE addition: 0.73; 95% CI, 0.66-0.81) and Precision Medicine in Cardiomyopathy score (before LGE addition: 0.68; 95% CI, 0.49-0.77; after LGE addition: 0.73; 95% CI, 0.64-0.82) SCD predictive models. In this retrospective cohort study, quantitative LGE was a risk factor for SCD in patients younger than 21 years with HCM and improved risk stratification.

Fetal haemoglobin and oxygen requirement in preterm infants: an observational study

ObjectiveTo investigate the relationship between the fraction of fetal haemoglobin (HbF(%)) and oxygen requirement as determined by the fraction of inspired oxygen (FiO2) and alveolar–arterial gradient (A–a gradient). Increased alveolar...