The accurate assessment of cardiac motion is crucial for diagnosing and monitoring cardiovascular diseases.In this context,digital volume correlation(DVC)has emerged as a promising technique for tracking cardiac motio...The accurate assessment of cardiac motion is crucial for diagnosing and monitoring cardiovascular diseases.In this context,digital volume correlation(DVC)has emerged as a promising technique for tracking cardiac motion from cardiac computed tomography angiographic(CTA)images.This paper presents a comprehensive performance evaluation of the DVC method,specifically focusing on tracking the motion of the left atrium using cardiac CTA data.The study employed a comparative experimental approach while simultaneously optimizing the existing DVC algorithm.Multiple sets of controlled experiments were designed to conduct quantitative analyses on the parameters“radius”and“step”.The results revealed that the optimized DVC algorithm enhanced tracking accuracy within a reasonable computational time.These findings contributed to the understanding of the efficacy and limitations of the DVC algorithm in analyzing heart deformation.展开更多
Atrium spaces,common in modern construction,provide significant fire safety challenges due to their large vertical openings,which facilitate rapid smoke spread and reduce sprinkler effectiveness.Traditional smoke mana...Atrium spaces,common in modern construction,provide significant fire safety challenges due to their large vertical openings,which facilitate rapid smoke spread and reduce sprinkler effectiveness.Traditional smoke management systems primarily rely on make-up air to replace the air expelled through vents.Inadequate calibration,particularly with air velocity,can worsen fire conditions by enhancing oxygen supply,increasing soot production,and reducing visibility,so endangering safe evacuation.This study investigates the impact of make-up air velocity on smoke behaviour in atrium environments through 24 simulations performed using the FireDynamics Simulator(FDS).Scenarios include various fire intensities(1,3,5 MW)and make-up air velocities(1–3.5 m/s),with fire sources located at the centre,northeast,and southwest corners.The simulation model was validated using updated full-scale fire test data with polystyrene fuel,leading to heightened soot density and reduced smoke clear height.This Research design diverges from other studies that predominantly utilized propane pool fires and concentrated on axisymmetric(Fire at the center of the atrum),Northeast and Southeast corners of the atrium scenarios by using polystyrene-a widely accessible construction material and examining several asymetric fire sites,so providing a more authentic depiction of atrium fire settings.Research reveals that increased air velocities,especially when directed at the fire,result in greater soot density and reduced smoke clearance due to intensified combustion.The northeastern region consistently displayed high temperature readings,highlighting the importance of fire source positioning in smoke behaviour.The study recommends limiting make-up air velocity to 1 m/s to avert turbulence and guarantee safety.This research provides critical insights for fire safety design and aligns with the United Nations Sustainable Development Goals,namely SDG 9 and SDG 11,by promoting safer and more resilient construction practices in urban environments.展开更多
Background and aims:Idiopathic premature ventricular contractions(PVCs)may cause subtle changes in left atrium(LA)structure and function.Here,we investigated whether serum sodium,body mass index(BMI),N-terminal pro-B-...Background and aims:Idiopathic premature ventricular contractions(PVCs)may cause subtle changes in left atrium(LA)structure and function.Here,we investigated whether serum sodium,body mass index(BMI),N-terminal pro-B-type natriuretic peptide(NT-proBNP)and other characteristics might be associated with LA in these patients.Methods:A total of 268 consecutive patients diagnosed with idiopathic PVCs were retrospectively analyzed.We assessed associations of enlarged LA and with the clinical features obtained from 24-hour Holter monitoring,electro-cardiography and serum data in patients with PVCs.Results:Patients with an enlarged LA(n=101),compared with a normal LA(n=167),had significantly lower serum sodium(140.9±3.0 mmol/L vs 141.7±2.8 mmol/L;P=0.022),higher BMI(24.5±2.7 kg/m2 vs 21.7±2.5 kg/m2;P<0.001),higher NT-proBNP[99.3(193.6)pg/mL vs 77.8(68.8)pg/mL;P<0.001]and lower average heart rates(73.0±8.0 bpm vs 75.3±7.6 bpm;P=0.019).No significant differences were observed in P-wave dispersion,QRS duration,PVC coupling interval,pleomorphism,circadian rhythm,non-sustained ventricular tachycardia,serum potassium,serum magnesium,hypersensitive C-reactive protein,low-density lipoprotein cholesterol,symptoms and PVC duration.Conclusions:Beyond the burden of PVCs,attributes such as serum sodium,BMI,NT-proBNP and average heart beats may potentially correlate with LA enlargement in individuals with idiopathic PVCs.展开更多
Since the research on verification to passive design strategies in sustainable building is at the initial stage,and its test method and verification conclusion are not scientific enough to validate,this paper proposes...Since the research on verification to passive design strategies in sustainable building is at the initial stage,and its test method and verification conclusion are not scientific enough to validate,this paper proposes the necessity of building physical environmental monitoring to quantitative optimization of passive strategies efficiency from the perspective of architecture design and building environment. Adopting comparative research method,this research chooses six types of atrium space in cold climate in China as a prototype,focusing on building physical environmental performance difference in and between atrium and building main space. Spatial parameters of the atrium space will be divided into four factors: spatial geometry,interfacial properties,internal and external related categories. With subdividing these four factors into sub-factors,this paper makes crosscomparison among the sub-factors to clarify passive strategies effectiveness in atrium. Data comparison analysis shows that Winter atrium passive strategy in cold regions from traditional view is not obvious in practical application,and test data need to be stratified refined in atrium design in case of optimizing passive strategy from building prototype perspective.展开更多
Based on the thermal and velocity layer's theory,the experimental setup was established on large space atrium under nozzle outlet. A series of winter experiments were accomplished and the following conclusions cou...Based on the thermal and velocity layer's theory,the experimental setup was established on large space atrium under nozzle outlet. A series of winter experiments were accomplished and the following conclusions could be drawn. At the sunny day of winter in Shanghai,the thermal and velocity layer are similar. The height of the both layer is 10-30 mm,and the temperature gratitude is 5-10 ℃ /m. Decreasing the angle of the nozzle outlet can increase the layer height dramatically. The maximum temperature difference of the occupant zone has relation with the angle of the nozzle outlet. The less the angle of the nozzle outlet is set,the greater the temperature difference is. The occupant temperature differences at these angles of the nozzle outlet are 5.1-4.4 ℃. The velocity of the wind is 0.02 and 0.17 m/s and they can accord with design demand. So,it can decrease the temperature gratitude by about 30% and it can save 10%-15% energy consumption.展开更多
As a transition space,atrium not only organizes traffic,makes the flow line flexible,but also modulates the indoor micro-climate. Because of its good sense of space and lighting performance,designers generally set rea...As a transition space,atrium not only organizes traffic,makes the flow line flexible,but also modulates the indoor micro-climate. Because of its good sense of space and lighting performance,designers generally set reading space around the atrium. But nowadays,people are more concerned with the external form of the architecture,rather than the thermal comfort conditions of the atrium reading space. This article chooses the universities' library atrium space of Harbin in typical city in cold regions as the carrier of research,testes the thermal environment of atrium reading space, analyzes the user 's subjective feelings of the thermal environment and establishes climate adaptation model applied to library buildings. This paper aims to study on Winter thermal comfort of universities' library atrium reading space in cold area. Bases on thermal comfort adaptive model,it establishes a reasonable heating methods and design temperature index of indoor thermal environment. Optimum comfort is obtained while achieving building energy efficiency and providing viewers a comfortable reading space.展开更多
Infective endocarditis(IE) remains a serious disease. Aorta-to-right atrium fistula is a rare but very serious complication of IE and predicts a higher mortality. This report describes a 50-year-old man with endocardi...Infective endocarditis(IE) remains a serious disease. Aorta-to-right atrium fistula is a rare but very serious complication of IE and predicts a higher mortality. This report describes a 50-year-old man with endocarditis,vegetation,perforation of noncoronary sinus,and formation of two aorta-to-right atrium fistulas with native valves detected by transthoracic echocardiography. This disease is lethal despite developments in cardiac imaging and antibacterial therapy. Early diagnosis,aggressive antibacterial therapy,and surgical treatment may improve the prognosis.展开更多
BACKGROUND MicroRNA-21(miR-21)is related to hypertension and cardiac remodelling.Left atrium(LA)dilation is highly sensitive to small haemodynamic changes in the left ventricle(LV)that are induced by hypertension.This...BACKGROUND MicroRNA-21(miR-21)is related to hypertension and cardiac remodelling.Left atrium(LA)dilation is highly sensitive to small haemodynamic changes in the left ventricle(LV)that are induced by hypertension.This study aimed to elucidate the relationship between miR-21 expression and LA dilation in elderly patients with essential hypertension(EH).METHODS In this cross-sectional study,one hundred elderly patients with EH were recruited for the study.According to their left atrium diameters(LADs),the patients were divided into the LA dilation group[42 patients(42%)]and the no-LA dilation group[58 patients(58%)].The serum levels of miR-21 and chemical biomarkers used in the clinic,such as creatinine,blood urea nitrogen,uric acid,fasting blood glucose,total cholesterol(TC),triglyceride(TG),high-density lipoprotein cholesterol(HDLC),low-density lipoprotein cholesterol(LDL-C),very-low-density lipoprotein cholesterol,Lp(a),apolipoprotein A1(apoA1),and apolipoprotein B,were measured.All the patients underwent echocardiographic examination,and the LAD,interventricular septum(IVS),right atrium diameter(RAD),right ventricle diameter(RVD),left ventricular end-systolic diameter(LVESD),left ventricular end-systolic diameter(LVEDD)and left ventricular ejection fraction(LVEF)were measured.RESULTS The levels of miR-21[8.02(5.21,14.39)vs.6.05(3.81,8.95),P=0.011]and LVEF(67.02±3.82 vs.64.14±4.43,P=0.001)were higher in the LA dilation group.The levels of creatinine[70.40(64.45,80.15)vs.63.9(60.1,73.43)],P=0.020]were higher in the no-LA dilation group.The levels of HDLC(r=-0.209,P=0.037),apoA1(r=-0.269,P=0.007)and RAD(r=0.203,P=0.043)were significantly correlated with miR-21 expression.The LAD was significantly correlated with the RAD(r=0.287,P=0.004),RVD(r=0.450,P<0.001),LVEDD(r=0.248,P=0.013)and LVEF(r=0.232,P=0.020).Multivariate logistic regression revealed that miR-21 significantly influenced LA dilation in elderly patients with EH(P<0.05).CONCLUSIONS Circulating serum levels of miR-21 are increased in elderly patients with EH with LA dilation.miR-21 levels are significantly correlated with LA dilation in elderly patients with EH,and miR-21 may be a factor related to the clinical pathophysiological occurrence of and treatment for the progression of hypertension-related early heart damage in EH patients.展开更多
Usually, cardiac calcifications are observed in aortic and mitral valves, atrio-ventricular plane, mitral annulus, coronary arteries, pericaridium(usually causing constrictive pericarditis) and cardiac masses. Calcifi...Usually, cardiac calcifications are observed in aortic and mitral valves, atrio-ventricular plane, mitral annulus, coronary arteries, pericaridium(usually causing constrictive pericarditis) and cardiac masses. Calcifications of atrial walls are unusual findings that can be identified only using imaging with high spatial resolution, such as cardiac magnetic resonance and computed tomography. We report a case of a 43-year-old patient with no history of heart disease that underwent cardiac evaluation for mild dyspnoea. The echocardiogram showed a calcific aortic valve and a hyper-echogenic lesion located in atrio-ventricular plane. The patient was submitted to cardiac magnetic resonance and to computed tomography imaging to better characterize the localization of mass. The clinical features and location of calcified lesion suggest an infective aetiology causing an endocarditis involving the aortic valve, atrioventricular plane and left atrium. Although we haven't data to support a definite and clear diagnosis, the clinical features and location of the calcified lesion suggest an infective aetiology causing an endocarditis involving the aortic valve, atrio-ventricular plane and left atrium. The patient was followed for 12 mo both clinically and by electrocardiogram and echocardiography without worsening of clinical, electrocardiographic and echocardiographic data. Cardiac magnetic resonance imaging and computed tomography are ideal methods for identifying and following over time patients with calcific degeneration in the heart.展开更多
In this study a 10-storied residential building model was employed to clarify the ventilation characteristics of the atrium and the rooms,which were effected by the different forms of lateral openings.The experiment w...In this study a 10-storied residential building model was employed to clarify the ventilation characteristics of the atrium and the rooms,which were effected by the different forms of lateral openings.The experiment was conducted under the combined effect of wind force and thermal buoyancy,and the similarity requirements were satisfied.The results have shown that the different forms of lateral openings cause the different ventilation effect of the building,and also have some certain regularity.The conclusions provide a theoretical foundation for how to use the ventilation of atrium better in high-rise residential building.展开更多
Dystrophic cardiac calcification is often associated with conditions causing systemic inflammation and when present,is usually extensive,often encompassing multiple cardiac chambers and valves.We present an unusual ca...Dystrophic cardiac calcification is often associated with conditions causing systemic inflammation and when present,is usually extensive,often encompassing multiple cardiac chambers and valves.We present an unusual case of dystrophic left atrial calcification in the setting of end stage renal disease on hemodialysis diagnosed by echocardiography and computed tomography.Significant calcium deposition is confined within the walls of the left atrium with no involvement of the mitral valve,and no hemodynamic effects.展开更多
Objective To investigate the effects of ethanol on physiological characteristics of the isolated guinea pig left atrium and papillary muscles.Methods The effects of ethanol on contractility, post-rest potentiation a...Objective To investigate the effects of ethanol on physiological characteristics of the isolated guinea pig left atrium and papillary muscles.Methods The effects of ethanol on contractility, post-rest potentiation and positive staircase phenomenon were observed in isolated left atrium and papillary muscles of guinea pig.Results Ethanol(50.0,100.0,200.0mmol·L -1)prominently inhibited the contraction of papillary muscles. Ethanol(12.5,25.0,50.0,100.0,200.0mmol·L -1) inhibited the contraction of left atrium, and markedly decreased the post-rest potentiation of myocardial contractility in left atrium. High concentration of ethanol(100,200mmol·L -1) depressed the positive staircase phenomenon of isolated guinea pig left atrium.Conclusion These results suggest that ethanol induces inhibitory effects of the contractility, post-rest potentiation, positive staircase phenomenon of left atrium. The mechanism by which ethanol induces the negative inotropic effects may be related to decrease the amount of calcium released from the intracellular stores.展开更多
Background:To evaluate the qualitative and quantitative differences between intracardiac and extracardiac vascular malformations in patients with a single atrium(SA),single ventricle(SV)and single atrium-single ventri...Background:To evaluate the qualitative and quantitative differences between intracardiac and extracardiac vascular malformations in patients with a single atrium(SA),single ventricle(SV)and single atrium-single ventricle(SA-SV)using dual-source CT(DSCT),and to compare the diagnostic performances of DSCT and transthoracic echocardiography(TTE).Methods:This retrospective study included 24 SA,75 SV and 24 SA-SV patients who underwent both DSCT and TTE before surgery.The diagnostic values of DSCT and TTE for intracardiac and extracardiac malformations were compared according to the surgical results.The diameters of the major artery and vein were measured and calculated based on DSCT and compared among the three groups.Results:The most common malformation was pulmonary artery disease in SA(50.0%)and SA-SV(45.8%)groups and patent ductus arteriosus(33.3%)in SV group.Although there was no statistical difference,arterial development was relatively poor in the SA group.All groups showed the trend of pulmonary artery stenosis(SA vs.SV vs.SA-SV:50.0%vs.30.7%vs.33.3%).There was a significant difference in mean pulmonary vein index among the groups(p=0.017).The diagnostic sensitivity of DSCT was superior to that of TTE for extracardiac malformations.Conclusions:The most common malformation in SA and SA-SV patients is pulmonary artery stenosis.SV patients are most likely to be complicated with patent ductus arteriosus.DSCT is more advantageous than TTE for diagnosing combined extracardiac malformations and can accurately measure the diameter of arteriovenous vessels.展开更多
Full-scale experimental measurements and modified k-ε two-equation computational fluid dynamics(CFD) model with buoyancy term are used to investigate temperature field of the single-sided natural ventilated atrium wi...Full-scale experimental measurements and modified k-ε two-equation computational fluid dynamics(CFD) model with buoyancy term are used to investigate temperature field of the single-sided natural ventilated atrium with large openings. Compared with the measured values, the modified k-ε turbulent mode can effectively simulate the low Reynold number airflow in the single-side naturally ventilated atrium. Based on the experiment, the optimum period of utilizing natural ventilation for indoor climate control was determined. And the characteristic of the temperature field was analyzed and classified into two zones:lower linear temperature distribution zone and upper thermal accumulation area where temperature is power function distributed. These can be referenced for design and operation of atrium in north China.展开更多
Hemodynamic instability secondary to left atrial (LA) compression by an aortic aneurysm is a rare entity. We report?the case of a 43-year old woman with no previous diagnosis of congestive heart failure who was admitt...Hemodynamic instability secondary to left atrial (LA) compression by an aortic aneurysm is a rare entity. We report?the case of a 43-year old woman with no previous diagnosis of congestive heart failure who was admitted for an initial diagnosis of pulmonary embolism (PE) based on shortness of breath, hypotension and D-Dimers?elevation. The electrocardiogram and blood counts were within normal limits. The chest X-ray revealed widening of the mediastinum. Transthoracic echocardiography demonstrated LA compression by a large descending thoracic aortic aneurysm. Left and right ventricle systolic functions were preserved. Chest angiography showed LA and left pulmonary artery (LPA) compression by a descending aortic aneurysm and an intramural hematoma with no evidence of PE evidence. Emergency surgery could not be done because of her financial status. She was treated medically and was discharged 1?week later with significant improvement. However she remained hypotensive.展开更多
BACKGROUND Pulmonary artery-to-left atrial fistula is a variant of pulmonary arteriovenous fistula and is a developmental anomaly.Delayed presentation,cyanosis and effort intolerance are some of the important features...BACKGROUND Pulmonary artery-to-left atrial fistula is a variant of pulmonary arteriovenous fistula and is a developmental anomaly.Delayed presentation,cyanosis and effort intolerance are some of the important features.The diagnosis is confirmed by computed tomography or pulmonary artery angiography.Catheter-based closure is preferred to surgery.CASE SUMMARY Left pulmonary artery-to-left atrial fistula is rare.A 40-year-old male presented with effort intolerance,central cyanosis,and recurrent seizures.He had a large and highly tortuous left pulmonary artery-to-left atrial fistula associated with a large aneurysmal sac in the course.Catheter-based closure was performed using a vascular plug.CONCLUSION Left pulmonary artery-to-left atrial fistula is relatively uncommon compared to right pulmonary artery-to-left atrial fistula.Percutaneous closure by either a transeptal technique or guide wire insertion into the pulmonary vein through the pulmonary artery is preferred.The need for an arteriovenous loop depends on the tortuosity of the course of the fistula and the size of the device to be implanted because a larger device needs a larger sheath,necessitating firm guide wire support to facilitate negotiation of the stiff combination of the delivery sheath and dilator.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)is the most important primary malignant liver disease.A large proportion of patients with advanced HCC have macrovascular invasion.HCC tends to infiltrate vascular structures,pa...BACKGROUND Hepatocellular carcinoma(HCC)is the most important primary malignant liver disease.A large proportion of patients with advanced HCC have macrovascular invasion.HCC tends to infiltrate vascular structures,particularly the portal vein and its branches,and more rarely,the hepatic veins.The intravascular tumor thrombus can affect the inferior vena cava(IVC)or even the right atrium(RA),the latter having a poor prognosis.CASE SUMMARY HCC is one of the most aggressive malignant tumors.Tumor thrombus(TT)formation in advanced HCC stages is common and usually involves the hepatic or portal veins.Herein,we report a 69-year-old woman who presented with dyspnea to the emergency department.A ventilation/perfusion lung scan was performed,ruling out pulmonary embolism.Hepatopulmonary syndrome and portopulmonary hypertension were discarded with contrasted echocardiography,but a mass in the RA was detected and confirmed by cardiac magnetic resonance imaging.Abdominal computed tomography showed a liver mass with a dynamic enhancement pattern compatible with HCC and an intraluminal IVC mass extending from the hepatic vein into the RA.HCC with TT expansion to IVC and RA is rare and indicates poor prognosis.CONCLUSION HCC with TT expansion to IVC and RA is rare and indicates poor prognosis.There is no consensus about anticoagulation or other interventions in these patients.展开更多
The objective of this study was to describe the myxoma of the right atrium occurring in an 11-year-old girl. It was an 11</span><span style="font-family:Verdana;">-</span><span style=&qu...The objective of this study was to describe the myxoma of the right atrium occurring in an 11-year-old girl. It was an 11</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">year</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">old girl weighing 22 kg, admitted for exertional dyspnea, dry cough, palpitations, hepatitis, abdominal bloating, fever evolving for more than 9 months without a history of known cardiovascular disease;referral from a pulmonology department for cardiomegaly and right pleurisy.</span><span style="font-family:""> </span><span style="font-family:Verdana;">At cardiac auscultation, the rhythm was irregular</span><span style="font-family:Verdana;">ly</span><span style="font-family:Verdana;"> fast at 130 beats without added noise with a blood pressure of 110/65</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">mmhg. In the lungs, there was silence and a decrease in vocal vibrations at the right base, SaO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> at 70%. Elsewhere a thoracic collateral venous circulation was visible. Electrocardiogram recorded rapid atrial fibrillation at 134 cycles. The cardiac ultrasound concluded that there was a mobile mass in the right atrium prolapsing in the right ventricle measuring 25 mm × 18.9 mm suggesting a myxoma. The myxoma of the right atrium is of a rare localization with a polymorphic clinical manifestation. It should be diagnosed as early as possible to avoid the occurrence of dreaded complications. Its management is surgical.展开更多
Aim: To present the aneurysmal dilatation of left atrium due to rheumatic mitral valve disease and its clinical consequences such as arrhythmic, thromboembolic and compressive manifestations. Introduction: Extreme enl...Aim: To present the aneurysmal dilatation of left atrium due to rheumatic mitral valve disease and its clinical consequences such as arrhythmic, thromboembolic and compressive manifestations. Introduction: Extreme enlargement of left atrium, usually referred to as giant, gigantic or aneurysmal dilatation is an uncommon finding with a reported incidence of 0.3% in rheumatic heart disease. It is an important clinical risk identifier to predict the outcome of cardiovascular disease. Case reports: Aneurysmal left atrium correlating with the length of pure mitral regurgitation jet in a 18-year-old girl, posterior mitral leaflet prolapse with regurgitation jet swirling around the entire interatrial septum in a 37-year-old male, Giant left atrium in mixed mitral valve disease in a 37-year-old female and a thrombosed giant left atrium resembling as “coconut” in a 50-year-old female were reported. Conclusion: Giant left atrium may be misinterpreted as right-sided pleural effusion, pericardial effusion and mediastinal tumor on X-ray chest and so echocardiographic evaluation is mandatory to exclude the aneurysmal left atrium in such conditions.展开更多
基金supported by the Australian Research Council(ARC)(Grant No.DP200103492)the National Natural Science Foundation of China(Grant Nos.12172089,12372307,and 61821002)+2 种基金Medical Research Future Fund(Grant Nos.2016165 and 2023977)the CBT Early Career Researcher Grant funded and the Roland Bishop Biomedical Engineering Research Award by Queensland University of Technologythe Springboard Funding and the Global Collaboration Funding by London South Bank University.Computational resources and services used in this work were provided by the High-Performance Computing and Research Support Group,Queensland University of Technology,Brisbane,Australia.
文摘The accurate assessment of cardiac motion is crucial for diagnosing and monitoring cardiovascular diseases.In this context,digital volume correlation(DVC)has emerged as a promising technique for tracking cardiac motion from cardiac computed tomography angiographic(CTA)images.This paper presents a comprehensive performance evaluation of the DVC method,specifically focusing on tracking the motion of the left atrium using cardiac CTA data.The study employed a comparative experimental approach while simultaneously optimizing the existing DVC algorithm.Multiple sets of controlled experiments were designed to conduct quantitative analyses on the parameters“radius”and“step”.The results revealed that the optimized DVC algorithm enhanced tracking accuracy within a reasonable computational time.These findings contributed to the understanding of the efficacy and limitations of the DVC algorithm in analyzing heart deformation.
文摘Atrium spaces,common in modern construction,provide significant fire safety challenges due to their large vertical openings,which facilitate rapid smoke spread and reduce sprinkler effectiveness.Traditional smoke management systems primarily rely on make-up air to replace the air expelled through vents.Inadequate calibration,particularly with air velocity,can worsen fire conditions by enhancing oxygen supply,increasing soot production,and reducing visibility,so endangering safe evacuation.This study investigates the impact of make-up air velocity on smoke behaviour in atrium environments through 24 simulations performed using the FireDynamics Simulator(FDS).Scenarios include various fire intensities(1,3,5 MW)and make-up air velocities(1–3.5 m/s),with fire sources located at the centre,northeast,and southwest corners.The simulation model was validated using updated full-scale fire test data with polystyrene fuel,leading to heightened soot density and reduced smoke clear height.This Research design diverges from other studies that predominantly utilized propane pool fires and concentrated on axisymmetric(Fire at the center of the atrum),Northeast and Southeast corners of the atrium scenarios by using polystyrene-a widely accessible construction material and examining several asymetric fire sites,so providing a more authentic depiction of atrium fire settings.Research reveals that increased air velocities,especially when directed at the fire,result in greater soot density and reduced smoke clearance due to intensified combustion.The northeastern region consistently displayed high temperature readings,highlighting the importance of fire source positioning in smoke behaviour.The study recommends limiting make-up air velocity to 1 m/s to avert turbulence and guarantee safety.This research provides critical insights for fire safety design and aligns with the United Nations Sustainable Development Goals,namely SDG 9 and SDG 11,by promoting safer and more resilient construction practices in urban environments.
文摘Background and aims:Idiopathic premature ventricular contractions(PVCs)may cause subtle changes in left atrium(LA)structure and function.Here,we investigated whether serum sodium,body mass index(BMI),N-terminal pro-B-type natriuretic peptide(NT-proBNP)and other characteristics might be associated with LA in these patients.Methods:A total of 268 consecutive patients diagnosed with idiopathic PVCs were retrospectively analyzed.We assessed associations of enlarged LA and with the clinical features obtained from 24-hour Holter monitoring,electro-cardiography and serum data in patients with PVCs.Results:Patients with an enlarged LA(n=101),compared with a normal LA(n=167),had significantly lower serum sodium(140.9±3.0 mmol/L vs 141.7±2.8 mmol/L;P=0.022),higher BMI(24.5±2.7 kg/m2 vs 21.7±2.5 kg/m2;P<0.001),higher NT-proBNP[99.3(193.6)pg/mL vs 77.8(68.8)pg/mL;P<0.001]and lower average heart rates(73.0±8.0 bpm vs 75.3±7.6 bpm;P=0.019).No significant differences were observed in P-wave dispersion,QRS duration,PVC coupling interval,pleomorphism,circadian rhythm,non-sustained ventricular tachycardia,serum potassium,serum magnesium,hypersensitive C-reactive protein,low-density lipoprotein cholesterol,symptoms and PVC duration.Conclusions:Beyond the burden of PVCs,attributes such as serum sodium,BMI,NT-proBNP and average heart beats may potentially correlate with LA enlargement in individuals with idiopathic PVCs.
基金Sponsored by the Key Project of National Natural Science Foundation of China (Grant No.51138004)the National Science and Technology Support Program (Grant No.2012BAJ10B02)
文摘Since the research on verification to passive design strategies in sustainable building is at the initial stage,and its test method and verification conclusion are not scientific enough to validate,this paper proposes the necessity of building physical environmental monitoring to quantitative optimization of passive strategies efficiency from the perspective of architecture design and building environment. Adopting comparative research method,this research chooses six types of atrium space in cold climate in China as a prototype,focusing on building physical environmental performance difference in and between atrium and building main space. Spatial parameters of the atrium space will be divided into four factors: spatial geometry,interfacial properties,internal and external related categories. With subdividing these four factors into sub-factors,this paper makes crosscomparison among the sub-factors to clarify passive strategies effectiveness in atrium. Data comparison analysis shows that Winter atrium passive strategy in cold regions from traditional view is not obvious in practical application,and test data need to be stratified refined in atrium design in case of optimizing passive strategy from building prototype perspective.
基金Project(09YZ229) supported by Innovation Program of Shanghai Municipal Education Commission, ChinaProject(J50502) supported by Leading Academic Discipline of Shanghai Municipal Education Commission,China+2 种基金Project(50478113) supported by the National Natural Science Foundation of ChinaProject(2006BAJ02A05) supported by the National Key Technology R&D Program,ChinaProject(08DZ1203600) supported by the Shanghai Municipal Sciences and Technology Committee,China
文摘Based on the thermal and velocity layer's theory,the experimental setup was established on large space atrium under nozzle outlet. A series of winter experiments were accomplished and the following conclusions could be drawn. At the sunny day of winter in Shanghai,the thermal and velocity layer are similar. The height of the both layer is 10-30 mm,and the temperature gratitude is 5-10 ℃ /m. Decreasing the angle of the nozzle outlet can increase the layer height dramatically. The maximum temperature difference of the occupant zone has relation with the angle of the nozzle outlet. The less the angle of the nozzle outlet is set,the greater the temperature difference is. The occupant temperature differences at these angles of the nozzle outlet are 5.1-4.4 ℃. The velocity of the wind is 0.02 and 0.17 m/s and they can accord with design demand. So,it can decrease the temperature gratitude by about 30% and it can save 10%-15% energy consumption.
基金Sponsored by the National Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Technology of China(Grant No.2012BAJ06B04-02)
文摘As a transition space,atrium not only organizes traffic,makes the flow line flexible,but also modulates the indoor micro-climate. Because of its good sense of space and lighting performance,designers generally set reading space around the atrium. But nowadays,people are more concerned with the external form of the architecture,rather than the thermal comfort conditions of the atrium reading space. This article chooses the universities' library atrium space of Harbin in typical city in cold regions as the carrier of research,testes the thermal environment of atrium reading space, analyzes the user 's subjective feelings of the thermal environment and establishes climate adaptation model applied to library buildings. This paper aims to study on Winter thermal comfort of universities' library atrium reading space in cold area. Bases on thermal comfort adaptive model,it establishes a reasonable heating methods and design temperature index of indoor thermal environment. Optimum comfort is obtained while achieving building energy efficiency and providing viewers a comfortable reading space.
文摘Infective endocarditis(IE) remains a serious disease. Aorta-to-right atrium fistula is a rare but very serious complication of IE and predicts a higher mortality. This report describes a 50-year-old man with endocarditis,vegetation,perforation of noncoronary sinus,and formation of two aorta-to-right atrium fistulas with native valves detected by transthoracic echocardiography. This disease is lethal despite developments in cardiac imaging and antibacterial therapy. Early diagnosis,aggressive antibacterial therapy,and surgical treatment may improve the prognosis.
基金supported by the 2019 Hebei Science and Technology Project (grant number19 277787D)2019 Hebei Innovation Capability Promotion Project (grant number 199776249D)
文摘BACKGROUND MicroRNA-21(miR-21)is related to hypertension and cardiac remodelling.Left atrium(LA)dilation is highly sensitive to small haemodynamic changes in the left ventricle(LV)that are induced by hypertension.This study aimed to elucidate the relationship between miR-21 expression and LA dilation in elderly patients with essential hypertension(EH).METHODS In this cross-sectional study,one hundred elderly patients with EH were recruited for the study.According to their left atrium diameters(LADs),the patients were divided into the LA dilation group[42 patients(42%)]and the no-LA dilation group[58 patients(58%)].The serum levels of miR-21 and chemical biomarkers used in the clinic,such as creatinine,blood urea nitrogen,uric acid,fasting blood glucose,total cholesterol(TC),triglyceride(TG),high-density lipoprotein cholesterol(HDLC),low-density lipoprotein cholesterol(LDL-C),very-low-density lipoprotein cholesterol,Lp(a),apolipoprotein A1(apoA1),and apolipoprotein B,were measured.All the patients underwent echocardiographic examination,and the LAD,interventricular septum(IVS),right atrium diameter(RAD),right ventricle diameter(RVD),left ventricular end-systolic diameter(LVESD),left ventricular end-systolic diameter(LVEDD)and left ventricular ejection fraction(LVEF)were measured.RESULTS The levels of miR-21[8.02(5.21,14.39)vs.6.05(3.81,8.95),P=0.011]and LVEF(67.02±3.82 vs.64.14±4.43,P=0.001)were higher in the LA dilation group.The levels of creatinine[70.40(64.45,80.15)vs.63.9(60.1,73.43)],P=0.020]were higher in the no-LA dilation group.The levels of HDLC(r=-0.209,P=0.037),apoA1(r=-0.269,P=0.007)and RAD(r=0.203,P=0.043)were significantly correlated with miR-21 expression.The LAD was significantly correlated with the RAD(r=0.287,P=0.004),RVD(r=0.450,P<0.001),LVEDD(r=0.248,P=0.013)and LVEF(r=0.232,P=0.020).Multivariate logistic regression revealed that miR-21 significantly influenced LA dilation in elderly patients with EH(P<0.05).CONCLUSIONS Circulating serum levels of miR-21 are increased in elderly patients with EH with LA dilation.miR-21 levels are significantly correlated with LA dilation in elderly patients with EH,and miR-21 may be a factor related to the clinical pathophysiological occurrence of and treatment for the progression of hypertension-related early heart damage in EH patients.
文摘Usually, cardiac calcifications are observed in aortic and mitral valves, atrio-ventricular plane, mitral annulus, coronary arteries, pericaridium(usually causing constrictive pericarditis) and cardiac masses. Calcifications of atrial walls are unusual findings that can be identified only using imaging with high spatial resolution, such as cardiac magnetic resonance and computed tomography. We report a case of a 43-year-old patient with no history of heart disease that underwent cardiac evaluation for mild dyspnoea. The echocardiogram showed a calcific aortic valve and a hyper-echogenic lesion located in atrio-ventricular plane. The patient was submitted to cardiac magnetic resonance and to computed tomography imaging to better characterize the localization of mass. The clinical features and location of calcified lesion suggest an infective aetiology causing an endocarditis involving the aortic valve, atrioventricular plane and left atrium. Although we haven't data to support a definite and clear diagnosis, the clinical features and location of the calcified lesion suggest an infective aetiology causing an endocarditis involving the aortic valve, atrio-ventricular plane and left atrium. The patient was followed for 12 mo both clinically and by electrocardiogram and echocardiography without worsening of clinical, electrocardiographic and echocardiographic data. Cardiac magnetic resonance imaging and computed tomography are ideal methods for identifying and following over time patients with calcific degeneration in the heart.
基金Supported by the National Natural Science Foundation of China(50778064)Hunan Natural Science Foundation(07jj6088)
文摘In this study a 10-storied residential building model was employed to clarify the ventilation characteristics of the atrium and the rooms,which were effected by the different forms of lateral openings.The experiment was conducted under the combined effect of wind force and thermal buoyancy,and the similarity requirements were satisfied.The results have shown that the different forms of lateral openings cause the different ventilation effect of the building,and also have some certain regularity.The conclusions provide a theoretical foundation for how to use the ventilation of atrium better in high-rise residential building.
基金Supported by the "East Carolina Heart Institute"
文摘Dystrophic cardiac calcification is often associated with conditions causing systemic inflammation and when present,is usually extensive,often encompassing multiple cardiac chambers and valves.We present an unusual case of dystrophic left atrial calcification in the setting of end stage renal disease on hemodialysis diagnosed by echocardiography and computed tomography.Significant calcium deposition is confined within the walls of the left atrium with no involvement of the mitral valve,and no hemodynamic effects.
基金ThisresearchwassupportedbytheNationalNaturalScienceFoundationofChina (No .39870 334No .39970 2 73) ,theHighEducationalSpecialResearchFoundationforDoctorialSubject (No.2 0 0 10 6 980 34)andKeyItemofScientificTechnologyforMinistryofEducation (No .0 116 1)
文摘Objective To investigate the effects of ethanol on physiological characteristics of the isolated guinea pig left atrium and papillary muscles.Methods The effects of ethanol on contractility, post-rest potentiation and positive staircase phenomenon were observed in isolated left atrium and papillary muscles of guinea pig.Results Ethanol(50.0,100.0,200.0mmol·L -1)prominently inhibited the contraction of papillary muscles. Ethanol(12.5,25.0,50.0,100.0,200.0mmol·L -1) inhibited the contraction of left atrium, and markedly decreased the post-rest potentiation of myocardial contractility in left atrium. High concentration of ethanol(100,200mmol·L -1) depressed the positive staircase phenomenon of isolated guinea pig left atrium.Conclusion These results suggest that ethanol induces inhibitory effects of the contractility, post-rest potentiation, positive staircase phenomenon of left atrium. The mechanism by which ethanol induces the negative inotropic effects may be related to decrease the amount of calcium released from the intracellular stores.
基金This work was supported by Sichuan Science and Technology Program[2020YJ0229]1·3·5 Project for Disciplines of Excellence,West China Hospital,Sichuan University[ZYGD18013].
文摘Background:To evaluate the qualitative and quantitative differences between intracardiac and extracardiac vascular malformations in patients with a single atrium(SA),single ventricle(SV)and single atrium-single ventricle(SA-SV)using dual-source CT(DSCT),and to compare the diagnostic performances of DSCT and transthoracic echocardiography(TTE).Methods:This retrospective study included 24 SA,75 SV and 24 SA-SV patients who underwent both DSCT and TTE before surgery.The diagnostic values of DSCT and TTE for intracardiac and extracardiac malformations were compared according to the surgical results.The diameters of the major artery and vein were measured and calculated based on DSCT and compared among the three groups.Results:The most common malformation was pulmonary artery disease in SA(50.0%)and SA-SV(45.8%)groups and patent ductus arteriosus(33.3%)in SV group.Although there was no statistical difference,arterial development was relatively poor in the SA group.All groups showed the trend of pulmonary artery stenosis(SA vs.SV vs.SA-SV:50.0%vs.30.7%vs.33.3%).There was a significant difference in mean pulmonary vein index among the groups(p=0.017).The diagnostic sensitivity of DSCT was superior to that of TTE for extracardiac malformations.Conclusions:The most common malformation in SA and SA-SV patients is pulmonary artery stenosis.SV patients are most likely to be complicated with patent ductus arteriosus.DSCT is more advantageous than TTE for diagnosing combined extracardiac malformations and can accurately measure the diameter of arteriovenous vessels.
文摘Full-scale experimental measurements and modified k-ε two-equation computational fluid dynamics(CFD) model with buoyancy term are used to investigate temperature field of the single-sided natural ventilated atrium with large openings. Compared with the measured values, the modified k-ε turbulent mode can effectively simulate the low Reynold number airflow in the single-side naturally ventilated atrium. Based on the experiment, the optimum period of utilizing natural ventilation for indoor climate control was determined. And the characteristic of the temperature field was analyzed and classified into two zones:lower linear temperature distribution zone and upper thermal accumulation area where temperature is power function distributed. These can be referenced for design and operation of atrium in north China.
文摘Hemodynamic instability secondary to left atrial (LA) compression by an aortic aneurysm is a rare entity. We report?the case of a 43-year old woman with no previous diagnosis of congestive heart failure who was admitted for an initial diagnosis of pulmonary embolism (PE) based on shortness of breath, hypotension and D-Dimers?elevation. The electrocardiogram and blood counts were within normal limits. The chest X-ray revealed widening of the mediastinum. Transthoracic echocardiography demonstrated LA compression by a large descending thoracic aortic aneurysm. Left and right ventricle systolic functions were preserved. Chest angiography showed LA and left pulmonary artery (LPA) compression by a descending aortic aneurysm and an intramural hematoma with no evidence of PE evidence. Emergency surgery could not be done because of her financial status. She was treated medically and was discharged 1?week later with significant improvement. However she remained hypotensive.
文摘BACKGROUND Pulmonary artery-to-left atrial fistula is a variant of pulmonary arteriovenous fistula and is a developmental anomaly.Delayed presentation,cyanosis and effort intolerance are some of the important features.The diagnosis is confirmed by computed tomography or pulmonary artery angiography.Catheter-based closure is preferred to surgery.CASE SUMMARY Left pulmonary artery-to-left atrial fistula is rare.A 40-year-old male presented with effort intolerance,central cyanosis,and recurrent seizures.He had a large and highly tortuous left pulmonary artery-to-left atrial fistula associated with a large aneurysmal sac in the course.Catheter-based closure was performed using a vascular plug.CONCLUSION Left pulmonary artery-to-left atrial fistula is relatively uncommon compared to right pulmonary artery-to-left atrial fistula.Percutaneous closure by either a transeptal technique or guide wire insertion into the pulmonary vein through the pulmonary artery is preferred.The need for an arteriovenous loop depends on the tortuosity of the course of the fistula and the size of the device to be implanted because a larger device needs a larger sheath,necessitating firm guide wire support to facilitate negotiation of the stiff combination of the delivery sheath and dilator.
文摘BACKGROUND Hepatocellular carcinoma(HCC)is the most important primary malignant liver disease.A large proportion of patients with advanced HCC have macrovascular invasion.HCC tends to infiltrate vascular structures,particularly the portal vein and its branches,and more rarely,the hepatic veins.The intravascular tumor thrombus can affect the inferior vena cava(IVC)or even the right atrium(RA),the latter having a poor prognosis.CASE SUMMARY HCC is one of the most aggressive malignant tumors.Tumor thrombus(TT)formation in advanced HCC stages is common and usually involves the hepatic or portal veins.Herein,we report a 69-year-old woman who presented with dyspnea to the emergency department.A ventilation/perfusion lung scan was performed,ruling out pulmonary embolism.Hepatopulmonary syndrome and portopulmonary hypertension were discarded with contrasted echocardiography,but a mass in the RA was detected and confirmed by cardiac magnetic resonance imaging.Abdominal computed tomography showed a liver mass with a dynamic enhancement pattern compatible with HCC and an intraluminal IVC mass extending from the hepatic vein into the RA.HCC with TT expansion to IVC and RA is rare and indicates poor prognosis.CONCLUSION HCC with TT expansion to IVC and RA is rare and indicates poor prognosis.There is no consensus about anticoagulation or other interventions in these patients.
文摘The objective of this study was to describe the myxoma of the right atrium occurring in an 11-year-old girl. It was an 11</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">year</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">old girl weighing 22 kg, admitted for exertional dyspnea, dry cough, palpitations, hepatitis, abdominal bloating, fever evolving for more than 9 months without a history of known cardiovascular disease;referral from a pulmonology department for cardiomegaly and right pleurisy.</span><span style="font-family:""> </span><span style="font-family:Verdana;">At cardiac auscultation, the rhythm was irregular</span><span style="font-family:Verdana;">ly</span><span style="font-family:Verdana;"> fast at 130 beats without added noise with a blood pressure of 110/65</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">mmhg. In the lungs, there was silence and a decrease in vocal vibrations at the right base, SaO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> at 70%. Elsewhere a thoracic collateral venous circulation was visible. Electrocardiogram recorded rapid atrial fibrillation at 134 cycles. The cardiac ultrasound concluded that there was a mobile mass in the right atrium prolapsing in the right ventricle measuring 25 mm × 18.9 mm suggesting a myxoma. The myxoma of the right atrium is of a rare localization with a polymorphic clinical manifestation. It should be diagnosed as early as possible to avoid the occurrence of dreaded complications. Its management is surgical.
文摘Aim: To present the aneurysmal dilatation of left atrium due to rheumatic mitral valve disease and its clinical consequences such as arrhythmic, thromboembolic and compressive manifestations. Introduction: Extreme enlargement of left atrium, usually referred to as giant, gigantic or aneurysmal dilatation is an uncommon finding with a reported incidence of 0.3% in rheumatic heart disease. It is an important clinical risk identifier to predict the outcome of cardiovascular disease. Case reports: Aneurysmal left atrium correlating with the length of pure mitral regurgitation jet in a 18-year-old girl, posterior mitral leaflet prolapse with regurgitation jet swirling around the entire interatrial septum in a 37-year-old male, Giant left atrium in mixed mitral valve disease in a 37-year-old female and a thrombosed giant left atrium resembling as “coconut” in a 50-year-old female were reported. Conclusion: Giant left atrium may be misinterpreted as right-sided pleural effusion, pericardial effusion and mediastinal tumor on X-ray chest and so echocardiographic evaluation is mandatory to exclude the aneurysmal left atrium in such conditions.
