Search

Aiming at the problem of solder joint opening between front wheel cover plate and auxiliary water tank mounting bracket assembly in the process of PAVE test of a vehicle body structure, this paper finds out the failure reason of solder joint through structural stress analysis, and investigates several types of vehicle, combines CAE simulation analysis and vehicle’s own characteristic structure, puts forward two improved design schemes, considers each factor synthetically, and chooses the development scheme. A scheme with better cost and development cycle. The validation of the improved scheme shows that it not only effectively solders the solder joint opening problem between the front wheel cover plate and the auxiliary water tank mounting bracket assembly, meets the vehicle PAVE road test target requirements and improves the vehicle body reliability, but also takes into account the structural weight, setting cost and other factors, which is conducive to the lightweight design of the car body in white, and proves the effectiveness of the improved scheme.

BACKGROUND Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable myocardium disorder that predominantly affects the ventricle. Little is known about atrial involvement. This study aimed to assess atrial involvement, especially the role of genotype on atrium in ARVC. METHODS The incidence, characterization and predictors of atrial involvement were investigated. Nine known ARVC-causing genes were screened and the correlation between genotype and atrial involvement was assessed. RESULTS Right atrium (RA) dilation, left atrium (LA) dilation, and sustained atrial tachyarrhythmias (ATa) were found in 45, 16 and 3 patients, respectively. Gene mutations were identified in 64 (64.0%) patients. Mutation carriers showed more RA dilation than noncarriers (54.7% vs. 27.8%, P = 0.009), and no difference in LA dilation and ATa. Multivariate analysis showed tricuspid regurgitation (OR: 18.867; 95% CI: 1.466-250.000; P = 0.024) increased the risk of RA dilation and decreased left ventricular ejection fraction (LVEF) (OR: 1.134; 95% CI: 1.002-1.272; P = 0.031) correlated with LA dilation, whereas genotype showed no significant effect. At a median follow-up time of 91 months, 7 patients died and 1 patient accepted heart transplantation. New-onset RA dilation, LA dilation, and sustained ATa were found in 8, 7, and 6 patients, respectively. Atrial involvement was not associated with the long-term survival. Despite mutation carriers showing more RA dilation, Kaplan-Meier analysis showed genotype was not associated with atrial involvement. CONCLUSION Atrial involvement was common in ARVC. Tricuspid regurgitation and decreased LVEF increased the risk for atrial dilation. Genotype was not associated with atrial involvement.

Cardiac remodeling is one of major pathological process in hypertrophic cardiomyopathy (HCM). Endothelin-1 has been linked to cardiac remodeling. Big endothelin-1 is the precursor of endothelin-1.A total of 245 patients with HCM were enrolled from 1999 to 2011 and partitioned to low, middle and high level groups according to their plasma big endothelin-1 levels.At baseline, significant associations were found between high level of big endothelin-1 and left atrium size, heart function and atrial fibrillation. Big endothelin-1 was positively correlated with N-terminal B-type natriuretic peptide (r=0.291, p0.001) and late gadolinium enhancement (LGE) on magnetic resonance imaging (r=0.222, p=0.016). During a follow-up of 3 (range, 2-5) years, big endothelin-1 level was positively associated with the risks of all-cause mortality, cardiovascular death and progression to NYHA class 3 or 4 (p=0.020, 0.044 and 0.032, respectively). The rate of above events in the highest tertile were 18.1%, 15.7%, 24.2%, respectively. After adjusting for multiple factors related to survival and cardiac function, the significance remained in the association of big endothelin-1 with the risk of all-cause mortality (hazard ratio (HR)=4.94, 95% confidence interval (CI) 1.07-22.88; p=0.041) and progression to NYHA class 3 or 4 (HR=4.10, 95%CI 1.32-12.75, p=0.015).Our study showed that high level of plasma big endothelin-1 predicted prognosis for patients with HCM and it can be added to the marker panel in stratifying HCM patients for giving treatment priority to those at high risk.

Aims As the transseptal (TS) puncture has become an integral part of many types of cardiac interventional procedures, its technique that was initial reported for measurement of left atrial pressure in 1950s, continue to evolve. Our laboratory adopted a modified technique which uses only coronary sinus catheter as the landmark to accomplishing TS punctures under fluoroscopy. The aim of this study is prospectively to evaluate the training and learning process for TS puncture guided by this modified technique. Methods and results Guided by the training protocol, TS puncture was performed in 120 consecutive patients by three trainees without previous personal experience in TS catheterization and one experienced trainer as a controller. We analysed the following parameters: one puncture success rate, total procedure time, fluoroscopic time, and radiation dose. The learning curve was analysed using curve-fitting methodology. The first attempt at TS crossing was successful in 74 (82%), a second attempt was successful in 11 (12%), and 5 patients failed to puncture the interatrial septal finally. The average starting process time was 4.1 ± 0.8 min, and the estimated mean learning plateau was 1.2 ± 0.2 min. The estimated mean learning rate for process time was 25 ± 3 cases. Important aspects of learning curve can be estimated by fitting inverse curves for TS puncture. Conclusions The study demonstrated that this technique was a simple, safe, economic, and effective approach for learning of TS puncture. Base on the statistical analysis, approximately 29 TS punctures will be needed for trainee to pass the steepest area of learning curve.

In an attempt to construct an isogeometric analysis-suited geometry for isogeometric analysis, a new surface parameterization method using the one-step inverse forming (SPIA) is proposed. Initial generation of watertight analysis-suitable geometry (NURBS surfaces) with complex shapes can be a significant bottleneck for isogeometric analysis because computer-aided design models often include ambiguities such as gaps and overlaps. Most of traditional surface parameterization techniques are based on geometric method and limited to finite meshes, while SPIA is a physics-based method using sheet metal forming technique with large elastic–plastic deformation and robust enough and rapid to deal with the finite elements mesh with over 100,000 nodes within 2 min without the necessity to simplify the meshes. Using Coons surface parameterization, global mesh parameterization, and NURBS reconstruction, we can rebuild new computer-aided design models with errors under any tolerance to which isogeometric analysis can be applied. The NURBS surfaces after reconstruction are also used for computer-aided manufacturing.

Background— Vasovagal syncope (VVS) is the most common cause of recurrent syncope that can be debilitating despite optimal conventional therapy. The aim of this study was to evaluate the feasibility and efficacy of selective endocardial autonomic denervation in left atrium (LA) as an alternative treatment strategy in patients with highly symptomatic VVS. Methods and Results— Ten consecutive patients (mean age, 50.4±6.4 years; 7 women) with a medium of 3.5 (range, 2–20) recurrent episodes of VVS during the preceding year and positive head-up tilt testing in whom standard therapies were ineffective or poorly tolerated were enrolled. Ganglionated plexi (GP) in the LA, identified by high-frequency stimulation, was targeted by radiofrequency catheter ablation. The patients were then followed up at 3, 6, 12, 24, and 36 months, including repeated head-up tilt testing and Holter at 3 and 12 months. Radiofrequency energy was applied at the left superior GP in 10 patients, right anterior GP in 5, and left inferior GP in 3, using an 8-mm ablation catheter. Vagal response, defined as transient ventricular asystole, atrioventricular block, or an increase in R-R interval by 50%, was observed during ablation in all GP sites. The end point of procedure was the inhibition of the vagal response at target sites. At 30±16 (range, 13–55) months of follow-up, no patient had any recurrence of syncope and all patients had significant improvement in symptoms, but 5 of 10 patients reported transient prodromes. No complications occurred. Conclusions— Comprehensive endocardial autonomic denervation of the LA demonstrates the feasibility of treating VVS in medium-term follow-up.

To study the lock problem in the frontal collision test on a kind of mini vehicle’s sliding doors, this paper performs stress analysis on the lock mechanism of the sliding doors, and puts forward improvement methods. Through the theoretical calculations and frontal collision tests, this paper has verified the effectiveness of the improvement methods, and it provides the theoretical reference for the new vehicle models in the design stage.

BACKGROUND: An inverse relationship between body mass index (BMI) and circulating levels of N-terminal proB-type natriuretic peptide (NT-proBNP) has been demonstrated in subjects with and without heart failure. Obesity also has been linked with increased incidence of atrial fibrillation (AF), but its influence on NT-proBNP concentrations in AF patients remains unclear. This study aimed to investigate the effect of BMI on NT-proBNP levels in AF patients without heart failure. METHODS: A total of 239 consecutive patients with AF undergoing catheter ablation were evaluated. Levels of NT-proBNP and clinical characteristics were compared in overweight or obese (BMI≥25 kg/m2) and normal weight (BMI

Background— Although mutations of several genes are associated with arrhythmogenic right ventricular cardiomyopathy (ARVC), the exact correlation between genotype and ventricular arrhythmia features remains unclear. This study was aimed to examine the possible association of the 9 known genes of ARVC with clinical and electrophysiological characteristics. Methods and Results— Ninety subjects diagnosed with ARVC who underwent electrophysiological study were recruited for screening the 9 known ARVC-causing genes. A total of 53 mutations were identified in 57 (63%) subjects. Mutation carriers had more frequent clinical ventricular tachycardia (VT; 89% versus 55%; P 1 to V 3 (61% versus 33%; P =0.016). Subjects with plakophilin-2 ( PKP2 ) mutations also had more frequent VT than those without mutations in PKP2 . Comparison between subjects with multiple and single mutations showed that syncope occurred more often in the former group (58% versus 24%; P =0.018). VT was significantly more often induced in mutation carriers compared with noncarriers (75% versus 39%; P =0.001), as well as in PKP2 mutation carriers compared with subjects without PKP2 mutations (80% versus 48%; P =0.002). Induced VT with a rate ≥200 bpm was more often documented in mutation carriers (88% versus 54%; P =0.013), as well as in PKP2 mutation carriers (91% versus 67%; P =0.041). Conclusions— Pathogenic gene mutations were found in nearly two thirds of subjects diagnosed with ARVC. Mutation carriers, especially PKP2 , had a higher proportion of a history of VT and more inducible fast VT.

Objectives: The clinical outcomes of hypertrophic cardiomyopathy (HCM) are largely unpredictable. This study aimed to investigate the relationship between atrial fibrillation (AF) and its prognostic implications in Chinese patients with HCM. Methods: From 1999 to 2011, 654 unrelated HCM patients were consecutively recruited at Fuwai Hospital. Medical history, including electrocardiographic and echocardiographic data, was analyzed. Results: AF was documented in 158 patients (24%). During follow-up of 4.2 ± 2.8 years, Kaplan-Meier analysis revealed that the presence of AF was associated with an increased risk for all-cause death (p = 0.001), cardiovascular death (p < 0.001), severe heart failure (p < 0.001) and ischemic stroke (p < 0.001). Multivariate analysis identified AF as an independent predictor of stroke-related death (HR 6.71, 95% CI 1.23-38.58, p = 0.03), advanced heart failure (HR 1.83, 95% CI 1.04-3.22, p = 0.04) and ischemic stroke (HR 9.98, 95% CI 4.06-24.53, p < 0.001). Furthermore, enlarged left atrial diameter was positively related to all-cause death (HR 1.09, 95% CI 1.05-1.13, p < 0.001), cardiovascular death (HR 1.08, 95% CI 1.04-1.20, p < 0.001) and development of advanced heart failure (HR 1.05, 95% CI 1.01-1.10, p = 0.01). Conclusions: AF predicts poor outcomes for patients with HCM. Left atrial dilation is also related to an adverse prognosis and provides additional prognostic information.

Background Sex plays an important role in the clinical expression and prognosis of various cardiovascular diseases. This study was designed to observe the effects of sex on hypertrophic cardiomyopathy (HCM). Methods and Results A total of 621 unrelated patients with HCM without heart failure (460 males) were enrolled from 1999 to 2011. Compared to male patients, at baseline female patients were older at diagnosis (49.6±17.2 years vs. 46.7±14.4 years, P = 0.033), and had greater frequency of left ventricular outflow tract obstruction (72/161, 44.7% vs. 149/460, 32.4%, P = 0.005). During the average four year follow-up period (range 2–7 years), survival analysis showed that the incidences of mortality from all causes, cardiovascular death and progression to chronic heart failure were greater in women than in men (P = 0.031, 0.040 and 0.012, respectively). After adjustment for multiple factors that may confound survival and cardiac function, female sex remained an independent risk factor for all-cause mortality, cardiovascular death, and chronic heart failure [hazard ratio (HR) 2.19, 95% confidence interval (CI) 1.21–3.95, P = 0.010; HR 2.19, 95% CI 1.17–4.09, P = 0.014; HR 1.73, 95% CI 1.12–2.69, P = 0.014, respectively] in HCM patients. Subgroup analysis revealed that female sex as a risk factor was identified only in patients younger than 50 years old (P = 0.011, 0.011 and 0.009, respectively), but not for those 50 years or older. Conclusion Our results suggest that female sex is associated with worse survival and heart failure in HCM patients. Further studies are required to determine whether female hormones modify the clinical expression and prognosis of HCM.