Analysis of Electromagnetic Force And Formability of Tube Electromagnetic Bulging Based On Convex Magnetic Field Shaper

In order to solve the problems of non-uniform axial deformation and thinning of wall thickness in traditional tube electromagnetic bulging, a method of tube electromagnetic bulging based on convex magnetic field shaper is proposed in this paper. The electromagnetic-structure coupling model is constructed by using COMSOL software, and the influence of convex magnetic field shaper structure on radial and axial electromagnetic force, axial deformation uniformity and wall thickness reduction is analyzed, and compared with traditional tube electromagnetic bulging. The results show that by using this method, the axial deformation uniformity is increased by 4.2 times, and the relative wall thickness is reduced by 33%. Obviously, this method of tube bulging can effectively overcome the problems existing in traditional tube electromagnetic bulging and promote the wide application of electromagnetic forming technology.

Research on Application of Pulsed Eddy Current Testing in Nuclear Power Plant Pipelines

The condensate pipelines, main water supply pipelines, drain pipelines, and partial extraction pipelines of nuclear power plants are all coated with coatings on the outside of the pipelines to improve heat exchange efficiency. At present, the detection methods of ferromagnetic pipelines are mainly conventional ultrasound and ultrasonic guided waves. It is necessary to remove the insulation layer of the outer wall of the pipeline before the inspection, which leads to a prolonged inspection period and increased labor costs. This paper uses the measured and calculated values of the induced voltage to establish the optimal parameter inversion problem and combines the coupling relationship between the parameters to propose a reliable pulsed eddy current detection method for the relative wall thickness of ferromagnetic pipes. Using the pulsed eddy current detection method for the relative wall thickness of ferromagnetic pipelines proposed in this paper, the scanning detection of nuclear power plant steel pipes is compared with conventional ultrasonic testing. The detection results are reliable and suitable for non-destructive testing and evaluation of nuclear power plant ferromagnetic pipeline wall thickness corrosion thinning.

Abnormal left ventricular geometry in female collegiate swimmers

Background There is a paucity of data describing left ventricular geometry changes in female athletes. While some studies suggest that female athletes participating in dynamic sports exhibit higher prevalence of eccentric left ventricular hypertrophy (LVH) when compared to men, a recent study suggested more concentric geometry changes in female basketball athletes. We were unable to identify studies describing the left ventricular geometry of female collegiate swimmers. Objectives To describe LV geometry changes in a cohort of female collegiate swimmers. Methods We analyzed a cohort of female collegiate swimmers who had a pre-participation cardiac evaluation by 12-lead ECG and 2-dimensional echocardiography. Left ventricular (LV) geometry was assessed based on relative wall thickness (RWT) (defined as: 2 x posterior wall thickness (PWT) divided by LV end-diastolic diameter (LVEDD)) and LV mass (LVM) (Devereux's formula: LVM = [0.8 x 1.04 [(LVEDD + interventricular septum + posterior wall thickness)3 − (LVEDD)3]] + 0.6g) and was indexed to body surface area (BSA).LVH was defined as LV mass index >95 g and was defined as concentric when associated with a relative wall thickness (RWT) >0.42 and as eccentric when RWT was ≤0.42. Concentric remodeling was defined as normal LVM index and increased RWT. Results A total of 83 female collegiate swimmers were included. Their age was 18.5±0.5 years (mean ± standard deviation, SD), 74 (89.2%) were White, BSA was 1.78±0.11 m2, height 173±6.3 cm, weight 66.2±7.2 K. Their interventricular septum diameter was 0.89±0.14 cm, PWT 0.92±0.15 cm, LVEDD 4.9±0.5 cm and LV end-systolic diameter (LVESD) 3.2±0.4 cm. Left atrium diameter ranged from 2.6 to 4.3 cm (mean 3.4 cm ± 0.4 cm). Aortic root diameter ranged from 1.9 to 3.5 cm (mean 2.7±0.3 cm) (Figure 1). LVH was present in 27 swimmers (32.5%). Eccentric LVH was present in 17 athletes (20.5%), concentric hypertrophy in 10 athletes (12%), and concentric remodeling in 12 (14.5%) (Figure 2). No athletes with LVH or concentric remodeling had borderline or abnormal ECG findings based on international criteria. Only two women with normal LV geometry had abnormal ECG findings: prolonged QT interval and abnormal T wave inversion. There was a linear correlation between BSA with LVEDD, LVESD and LV mass (r=0.40, 0.35, and 0.48 with P<0.001,0.002 and <0.001, respectively). However, there was no statistically significant difference between LV geometry groups based on BSA or blood pressure. Conclusion Our data document a high incidence of eccentric hypertrophy among female collegiate swimmers. Concentric remodeling and hypertrophy were also relatively high. Differentiating physiologic from pathologic cardiac remodeling in these athletes is critical to prevent potential complications such as sudden cardiac death, arrhythmias, and other adverse outcomes. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): This work was supported in part by the American Medical Society for Sports Medicine (AMSSM) Foundation Research Grant 2016 awarded to KE, and the University of Florida REDCap uses the NIH National Center for Advancing Translational Sciences (NCATS) grant UL1 TR001427. Figure 1 Figure 2. LV geometry in female swimmers

THE CORRELATION OF RELATIVE WALL THICKNESS, LV MASS/LV MASS INDEX, CARDIAC INDEX AND PCWP IN RELATION TO SERUM FERRITIN IN TRANSFUSION DEPENDENT BETA THALASSMEIC CHILDREN IN NORTH WEST RAJASTHAN

Objective: Regular blood transfusions used for long term survival in ß-thalassemia major patients cause a secondary state of tissue iron overload. Myocardial iron deposition can result in cardiomyopathy, and heart failure remains the leading cause of death. This study was planned to see the correlation of Relative Wall Thickness (RWT), LV Mass, Cardiac Index(CI) and pulmonary capillary wedge pressure(PCWP) in relation to Serum Ferritin in transfusion dependent Beta Thalassemia children. Methods: Patients of ß thalassemia major above 2 years of age received regular blood transfusions at least for 1 year duration, attending OPD in the Department of Pediatrics, S.P. Medical College, Bikaner were enrolled. Echo findings of 50 cases were correlated with serum ferritin level(SFL). Result: Mean RWT in SFL group <2500ng/ml was 0.40±0.09, in SFL group 2500-5000 ng/ml, it was 0.41±0.08 and in SFL group >5000 ng/ml, it was 0.49±0.09; p value>0.05. Mean LV mass in SFL group <2500 was 68.76±24.32, in SFL group 2500-5000, it was 90.07±24.18 and in SFL group >5000, it was 123.06±42.42. The difference was found statistically highly significant (p<0.001). Mean PCWP in SFL group <2500 was 11.55±1.53, in SFL group 2500-5000, it was 12.02±2.06 and in SFL group >5000, mean PCWP was 13.31±2.09;p value>0.05. Mean CI in SFL group <2500 was 5.24±0.99, in 2500-5000 group was 5.79±1.07 and in SFL group >5000, it was 5.91±1.26 ; p value>0.05. Conclusion: There was significant positive correlation of serum ferritin level only with LV Mass.Relative Wall thickness, PCWP and cardiac index were insignificantly correlated. . Keywords: ß-thalassemia major; Relative wall thickness, LV mass/ LV mass index, cardiac index, PCWP, Echocardiogram; Tissue Doppler Imaging

Insulin resistance surrogates and left ventricular hypertrophy in normotensive obese children

Background: The relationship between different surrogates of insulin resistance and left ventricular geometry in obese children is still unclear. Objective: We sought to explore the relationship between commonly used measures of insulin sensitivity/resistance (homeostatic model assessment index, serum uric acid, and triglycerides to high-density lipoprotein cholesterol ratio) and left ventricular geometry in normotensive obese children. Methods: In this cross-sectional study, 32 normotensive obese children were examined. Transthoracic echocardiography was used to measure left ventricular mass index and relative wall thickness. Homeostasis model assessment index, serum uric acid level, and a ratio of triglycerides to high-density lipoprotein cholesterol were used as markers of the insulin resistance. Simple and partial correlation analyses (to control for the effects of body mass index) were conducted to explore relationship between studied variables and left ventricular mass index or relative wall thickness as outcome variables. Results: We found positive correlations between homeostasis model assessment index and relative wall thickness (r = 0.47, p = 0.03) which remained significant after controlling for the effect of body mass index, z-score (r = 0.48, p = 0.03). The cutoff level of homeostasis model assessment index with the optimum sensitivity (Sn) and specificity (Sp) derived from the receiver operating characteristic (ROC) curves for predicting concentric remodelling was ≥5.51 with Sn = 83.33 and Sp = 68.75. Conclusion: There is a positive relationship between homeostasis model assessment index and relative wall thickness of obese normotensive children which may help to distinguish at risk obese normotensive children for the development of concentric left ventricular remodelling.

Midventricular obstruction and left ventricular remodeling after transcatheter aortic valve implantation

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Grant of Russian Foundation for Basic Research Introduction Long existing pressure overload results in left ventricular (LV) hypertrophy in severe aortic stenosis (AS). Post-TAVI left ventricular remodeling after relief of the high-pressure overload could lead to manifestation of postprocedural midventricular obstruction caused mostly by marked LV wall hypertrophy with the interposition of the hypertrophic papillary muscle in small LV chamber. Our aim was to evaluate the incidence and predictors of midventricular obstruction during 1-year follow-up in patients with AS who underwent transcatheter aortic valve implantation. Methods 30 consecutive patients (mean age: 82.3 ± 5.6 years) with symptomatic severe AS who underwent TAVI in 2018-2019 in Almazov centre and survived &gt;12 months were enrolled in our observational, prospective, single-center study. Evolut R and Sapien-XT valves were used. All patients underwent transthoracic echocardiography before TAVI and at 3, 6, and 12 months after the procedure. There were no patients with baseline midventricular obstruction or concomitant hypertrophic obstructive cardiomyopathy. Results Procedure was successful in all cases. During 1 year of follow-up after TAVI, 3 patients (10%) demonstrated postprocedural midventricular obstruction with peak gradient ­– 36,3 ± 24,3 mm Hg. There was no difference in prosthetic diameter between obstructive and non-obstructive patients (27.0 ± 3,4 vs. 27.7 ± 5,1 mm, p = 0.85 - nonparametric Mann-Whitney U test for all comparisons). At baseline echocardiography, patients with midventricular obstruction had a significantly thicker interventricular septum (14.7 ± 2.5 vs. 11.5 ± 1.6mm, p &lt; 0.05), higher LV mass index (170.3 ± 63.6 vs. 121.0 ± 39.5 g/m2, p &lt; 0.05) and relative wall thickness (0.59 ± 0.03 vs. 0.49 ± 0.05 mm, p &lt; 0.02) compared with non-obstructive patients. Reductions in LV mass index were more significant in non-obstructive patients (49.8 ± 27.3 vs. 15.3 ± 15.0 g/m2, p &lt; 0.04); however, obstructive patients demonstrated higher reductions in end-systolic diameter (8.7 ± 7.1 vs. 0.3 ± 3.9 mm, p &lt; 0.05) and volume (21.7 ± 20.0 vs. 1.2 ± 8.4 mm, p &lt; 0.01) than non-obstructive patients throughout the 1-year follow-up. Midventricular obstruction peak gradient correlates strongly with preoperative relative wall thickness (rs=.73; p &lt; 0.001), moderate negatively with end-systolic LV diameter (rs=-.45; p &lt; 0.05). In the multiple regression analyses, preoperative relative wall thickness (p &lt; 0.001), reductions in interventricular septum (p &lt; 0.05) and posterior wall (p &lt; 0.05) thickness were identified as risk factors of postprocedural midventricular obstruction. Conclusions 10% of patients during 1 year of follow-up after TAVI demonstrate midventricular obstruction of various severity with poor reverse LV remodeling. Patients with a small hypertrophic left ventricle and high preoperative relative wall thickness, are at greater risk of development of the postprocedural midventricular obstruction.

Uncomplicated Monochorionic Twins: Two Normal Hearts Sharing One Placenta

Cardiovascular dysfunction has been reported in complicated monochorionic diamniotic (MCDA) pregnancies; however, little is known whether hemodynamic changes occur in uncomplicated MCDA twins. A prospective observational study was conducted including 100 uncomplicated MCDA twins matched by gestational age to 200 low-risk singletons. Echocardiography was performed at 26–30 weeks gestation and cord blood B-type natriuretic peptide (BNP) was measured at delivery. In both groups, z-scores for echocardiographic parameters were within normal ranges; however the monochorionic group had larger atrial areas (mean (standard deviation) right atria-to-heart ratio: 17.0 (2) vs. 15.9 (1); p = 0.018; left atria-to-heart ratio: 17.0 (3) vs. 15.8 (2); p < 0.001) and signs of concentric hypertrophy (right relative wall thickness: 0.66 (0.12) vs. 0.56 (0.11); p < 0.001; left relative wall thickness: 0.69 (0.14) vs. 0.58 (0.12); p < 0.001). Longitudinal function was increased in twins, leading to higher tricuspid annular plane systolic excursion (6.9 mm (0.9) vs. 5.9 mm (0.7); p < 0.001) and mitral annular plane systolic excursion (4.9 mm (0.8) vs. 4.4 mm (1.1); p < 0.001. BNP levels at birth were also higher in MCDA twins (median [interquartile range]: 20.81 pg/mL [16.69–34.01] vs. 13.14 pg/mL [9.17–19.84]; p < 0.001). Thus, uncomplicated MCDA fetuses have normal cardiac shape and function, but signs of cardiac adaptation were identified by echocardiographic and biochemical parameters, when compared with singletons.

Association of relative wall thickness of left ventricle with incidence of thromboembolism in patients with non-valvular atrial fibrillation: The Fushimi AF Registry

Aims Atrial fibrillation (AF) increases the risk of thromboembolism, such as ischaemic stroke or systemic embolism (SE). The aim of this study was to investigate the relationship between left ventricular relative wall thickness (RWT) and the risk of thromboembolism in patients with non-valvular AF. Methods and results The Fushimi AF Registry is a community-based prospective survey of the patients with AF in Japan. Analyses were performed on 3067 non-valvular AF patients, in which RWT values determined by transthoracic echocardiography were available at the baseline. The high-RWT group (RWT above the median) was more often female, older, and had higher systolic blood pressure, CHADS2 and CHA2DS2-VASc scores, as compared with low-RWT group. During the median follow-up period of 1309 days, there was a higher incidence of ischaemic stroke/SE in the high-RWT group [unadjusted hazard ratio (HR), 1.91; 95% confidence interval (CI), 1.42–2.59]. On multivariate Cox regression analysis, including the components of CHA2DS2-VASc score, left atrial diameter, oral anticoagulant prescription at baseline, and type of AF, high RWT was independently associated with ischaemic stroke/SE (adjusted HR, 1.81; 95% CI, 1.34–2.47). Stratified analysis demonstrated no significant interaction for any subgroups. In Kaplan–Meier analysis, ordinal RWT quartiles stratified the incidence of ischaemic stroke/SE. Finally, addition of RWT to CHA2DS2-VASc score increased the performance of risk stratification for the incidence of stroke/SE. Conclusion Relative wall thickness was independently associated with ischaemic stroke/SE among Japanese patients with non-valvular AF, suggesting the importance of left ventricular morphology in contributing to adverse outcomes, particularly thromboembolism.