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The Changes of Baroreflex Sensitivity During Head-up Tilt Test and Its Clinical Significance in the Patients with Vasovagal Syncope
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作者 胡兆霆 吕艳青 杨钧国 《South China Journal of Cardiology》 CAS 2001年第2期65-68,共4页
Objective To study thechanges of baroreflex sensitivity (BRS) during head - up tilt test (HUT) in patients with vasovagal syncope (VS), and to examine the relationship between baroreflex sensitivity and neurohormonal ... Objective To study thechanges of baroreflex sensitivity (BRS) during head - up tilt test (HUT) in patients with vasovagal syncope (VS), and to examine the relationship between baroreflex sensitivity and neurohormonal factors. Furthermore, to investigate the effects of the changes of BRS on VS. Methods Forty - two patients with unexplained syncope (Among the 42 patients, there were 22 patients with positive HUT and 20 patients with negative HUT respectively) and 20 healthy volunteers (with negative HUT) underwent passive head - up tilt testing, Ante-cubital vein blood samples were taken before and after HUT, or at syncope. The fasting plasma endothelin , serum nitric oxide (NO), serum NE were measured, the BRS was assessed on the basis of the linear regression slope the RR interval versus systolic arterial blood pressure during the increment in blood pressure after intravenous administration of phenylephrine. Results (1) During the syncope, the BRS significantly reduced in HUT(+) group than baseline. At the end of tilt, the level of plasma ET, serum NO in patients with positive HUT significantly increased compared with baseline or normal controls, and the plasma concentration of NE also had the trend of increase. (2) By multiple regression analysis, a significant negative correlation was found between baroreceptor sensitivity and the plasma ET, NO at the end of HUT in patients with positive HUT, but there was no relationship between BRS and NE. Conclusions During the syncope occure, the BRS in patients with VS decreased significantly compared with normal controls. The abnormal plasma ET, NO concen-tration might contribute to the mechanism of VS. 展开更多
关键词 Vasovagal syncope Head - up tilt test Endothelin Nitric oxide Baroreflex Sensitivity
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The Changes of Heart Rate Power Spectral Density during Head-up Tilt Test
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作者 陈椿 张馥敏 +1 位作者 黄元铸 马文珠 《The Journal of Biomedical Research》 CAS 1998年第1期21-24,共4页
To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained ... To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained syncope, including 15 positive patients (Group 1) and 35 negative patients(Group 2), and 15 negative healthy persons(Group 3) in 5 minute periods before and after tilting and 5 minutes before the end of test. HRPSD and their changes in total(T), very low-frequence(VLF), low-frequence(LF), high-frequence(HF) and the ratio of low/high frequence(LF/HF) were similar (P>0.05) 5 minutes before and after tilting among three groups. Five minutes before the end of test, Group 1 had obvious increase of T, VLF, LF and LF/HF while Group 2 and 3 had not such significant changes. There was significant difference(P<0.01) compared Group 1 with Group 2, 3. The results showed that the abnormal regulatory function of autonomic nervous system played an important role in the mechanism of symcope induced by HUT, the positive group had abnormal increase of sympathetic tone and imbalance of sympathetic/parasympathetic neural tone before syncope appeared. 展开更多
关键词 head-up tilt test SYNCOPE heart rate power spectral density autonomic nervous system
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Syncope as a health risk for soldiers: Influence of medical history and clinical findings on the sensitivity of head-up tilt table testing 被引量:1
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作者 Hans-Joachim Gilfrich Lena Marie Heidelmann +2 位作者 Franziska Grube Hagen Frickmann Sven Andreas Jungblut 《Journal of Medical Colleges of PLA(China)》 CAS 2015年第2期82-90,共9页
Background: Syncope is a relevant health problem in military environments. Reliable diagnosis is challenging. Tilt table testing is an important tool for syncope diagnosis. The aim of this study was to determine wheth... Background: Syncope is a relevant health problem in military environments. Reliable diagnosis is challenging. Tilt table testing is an important tool for syncope diagnosis. The aim of this study was to determine whether signs such as prodromal symptoms, co-morbidity, frequency of syncopal events, body length, body mass index, and electrocardiography(ECG) abnormalities can be used to predict the success of tilt table testing at diagnosing syncope.Methods: Data from 100 patients with histories of syncope or pre-syncope, who were diagnosed using head-up tilt table testing, were retrospectively analyzed in a cross-sectional analysis. The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation. Results: Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms, such as dizziness and sweating, significantly more often. The patients reported more injuries resulting from syncopal events and more previous syncopal events, and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing. An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension. However, patients with pathological reaction patterns during tilt table testing were significantly taller. This finding was detected for both females and males. No significant predictors were found in the ECG patterns of patients showing syncope during tilt table testing.Conclusions: Frequency of prior syncope and prodromal symptoms, and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis. In particular, if these factors are present, tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope. 展开更多
关键词 SYNCOPE head-up tilt testing PREDICTOR SOLDIERS Assessment HYPOTENSION
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Syncope as a health risk for soldiers-influence of medical history and clinical findings on the sensitivity of head-up tilt table testing
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作者 Hans-Joachim Gilfrich Lena Marie Heidelmann +2 位作者 Franziska Grube Hagen Frickmann Sven Andreas Jungblut 《Journal of Medical Colleges of PLA(China)》 CAS 2016年第1期34-42,共9页
Background:Syncope is a relevant health problem in military environments.Reliable diagnosis is challenging.Tilt table testing is an important tool for syncope diagnosis.The aim of this study was to determine whether s... Background:Syncope is a relevant health problem in military environments.Reliable diagnosis is challenging.Tilt table testing is an important tool for syncope diagnosis.The aim of this study was to determine whether signs such as prodromal symptoms,co-morbidity,frequency of syncopal events,body length,body mass index,and electrocardiography abnormalities can be used to predict the success of tilt table testing at diagnosing syncope.Methods:Data from 100 patients with histories of syncope or pre-syncope,who were diagnosed using head-up tilt table testing,were retrospectively analyzed in a cross-sectional analysis.The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation.Results:Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms,such as dizziness and sweating,significantly more often.The patients reported more injuries resulting from syncopal events and more previous syncopal events,and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing.An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension.However,patients with pathological reaction patterns during tilt table testing were significantly taller.This finding was detected for both females and males.No significant predictors were found in the electrocardiogram patterns of patients showing syncope during tilt table testing.Conclusions:Frequency of prior syncope and prodromal symptoms,and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis.In particular,if these factors are present,tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope. 展开更多
关键词 SYNCOPE head-up tilt testing PREDICTOR SOLDIERS Assessment HYPOTENSION
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Deceleration Capacity--A Novel Measure for Autonomic Nervous System in Patients with Vasovagal Syncope on Tilt-table Testing 被引量:9
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作者 黄芬 徐春芳 +5 位作者 邓小燕 左萍 林凡 樊静静 徐文佳 杨晓云 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2017年第3期326-331,共6页
This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained ... This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained syncope and 18 healthy subjects served as control group. According to whether bradycardia, hypotension or both took place during the onset of syncope, the patients were divided during the test into three subgroups: vasodepressor syncope(VD), cardioinhibitory syncope(CI) and mixed syncope(MX) subgroups. Heart rate, blood pressure, heart rate variability(HRV), and deceleration capacity(DC) were continuously analyzed during HUT. For all the subjects with positive responses, the normalized low frequency(LFn) and the LF/HF ratio markedly decreased whereas normalized high frequency(HFn) increased when syncope occurred. Syncopal period also caused more significant increase in the power of the DC in positive groups. These changes were more exaggerated compared to controls. All the patients were indicative of a sympathetic surge in the presence of withdrawal vagal activity before syncope and a sympathetic inhibition with a vagal predominance at the syncopal stage by the frequency-domain analysis of HRV. With the measurements of DC, a decreased vagal tone before syncope stage and a vagal activation at the syncopal stage were observed. The vagal tone was higher in subjects showing cardioinhibitory responses at the syncopal stage. DC may provide an alternative method to understand the autonomic profile of VVS patients. 展开更多
关键词 vasovagal syncope deceleration capacity heart rate variability head-up tilt-table testing
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Tilt table test today-state of the art 被引量:1
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作者 Nicholay Teodorovich Moshe Swissa 《World Journal of Cardiology》 CAS 2016年第3期277-282,共6页
A tilt table test(TTT) is an inexpensive, noninvasive tool for the differential diagnosis of syncope and orthostatic intolerance and has good diagnostic yield. The autonomic system malfunction which underlines the ref... A tilt table test(TTT) is an inexpensive, noninvasive tool for the differential diagnosis of syncope and orthostatic intolerance and has good diagnostic yield. The autonomic system malfunction which underlines the reflex syncope is manifested as either hypotension or bradycardia, while an orthostatic challenge is applied. The timing of the response to the orthostatic challenge, as well as the predominant component of the response help to differentiate between various forms of neurocardiogenic syncope, orthostatic hypotension and non-cardiovascular conditions(e.g., pseudosyncope). Medications, such as isoproterenol and nitrates, may increase TTT sensitivity. Sublingual nitrates are easiest to administer without the need of venous access. TTT can be combined with carotid sinus massage to evaluate carotid sinus hypersensitivity, which may not be present in supine position. TTT is not useful to access the response to treatment. Recently, implantable loop recorders(ILR) have been used to document cardioinhibitory reflex syncope, because pacemakers are beneficial in many of these patients, especially those over 45 years of age. The stepwise use of both TTT and ILR is a promising approach in these patients. Recently, TTT has been used for indications other than syncope, such as assessment of autonomic function in Parkinson's disease and its differentiation from multiple system atrophy. 展开更多
关键词 SYNCOPE ORTHOSTATIC INTOLERANCE tilt table test HYPOTENSION BRADYCARDIA
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Influence of Tilted Angle on Effective Linear Energy Transfer in Single Event Effect Tests for Integrated Circuits at 130 nm Technology Node 被引量:1
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作者 张乐情 卢健 +5 位作者 胥佳灵 刘小年 戴丽华 徐依然 毕大炜 张正选 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第11期119-122,共4页
A heavy-ion irradiation experiment is studied in digital storage cells with different design approaches in 130?nm CMOS bulk Si and silicon-on-insulator (SOI) technologies. The effectiveness of linear energy transf... A heavy-ion irradiation experiment is studied in digital storage cells with different design approaches in 130?nm CMOS bulk Si and silicon-on-insulator (SOI) technologies. The effectiveness of linear energy transfer (LET) with a tilted ion beam at the 130?nm technology node is obtained. Tests of tilted angles θ=0 ° , 30 ° and 60 ° with respect to the normal direction are performed under heavy-ion Kr with certain power whose LET is about 40?MeVcm 2 /mg at normal incidence. Error numbers in D flip-flop chains are used to determine their upset sensitivity at different incidence angles. It is indicated that the effective LETs for SOI and bulk Si are not exactly in inverse proportion to cosθ , furthermore the effective LET for SOI is more closely in inverse proportion to cosθ compared to bulk Si, which are also the well known behavior. It is interesting that, if we design the sample in the dual interlocked storage cell approach, the effective LET in bulk Si will look like inversely proportional to cosθ very well, which is also specifically explained. 展开更多
关键词 SOI Influence of tilted Angle on Effective Linear Energy Transfer in Single Event Effect tests for Integrated Circuits at 130 nm Tec
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Serious response during tilt-table test in elderly and its prophylactic management 被引量:2
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作者 韩阳 李晓霞 +2 位作者 蒋伟莉 王招娣 陈天秩 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2005年第4期304-306,共3页
Objective: To evaluate the serious response during tilt-table test (TTT) and its prophylactic management. Method: Seventy-six elderly patients were tested at a tilt angle of 70 degrees for a maximum of 45 min and then... Objective: To evaluate the serious response during tilt-table test (TTT) and its prophylactic management. Method: Seventy-six elderly patients were tested at a tilt angle of 70 degrees for a maximum of 45 min and then subjected to isoprotere- nol-provocative tilt testing. ECG and blood pressure were monitored during the test and patients were kept at normal saline con- dition through a peripheral intravenous duct. Results: Fifty-one of 76 patients were defined as positive including 23 having serious response; 6 of the 23 patients had arteriosclerosis involving internal carotid arteries and 7 cases had bradycardia, two of which were associated with II°-I A-V block and the others with chronic atrial fibrillation. The serious response consisted of cardiac arrest for more than 5 s (6 cases), or serious bradycardia for more than 1 min (7 cases) or serious hypotension for more than 1 min (10 cases). Those with serious response were managed by returning to supine position, thus driving up legs and intravenous atropine, CPR (2 cases with cardiac arrest) and needing oxygen supplementation (11 cases). Only 2 hypotension patients recovered gradually by 10 min after emergency management, while others recovered rapidly with no complications. Conclusion: Although non-invasive, TTT may result in serious response, especially in elderly. Therefore proper patient selection, control of isoproterenol infusion and close observation of vital signs are decisive for a safe consequence. 展开更多
关键词 血管迷走神经昏厥症 倾斜台实验 预防药 药品管理 动脉硬化
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Cardiac index (CI) versus cardio ankle vascular index (CAVI) at different degrees of head-up tilt (HUT) in healthy subjects
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作者 Akeel A. M. H. Zwain Riyadh W. Al Esawi Amina A. B. Al-Dejeli 《Open Journal of Molecular and Integrative Physiology》 2013年第2期71-79,共9页
The cardio-ankle vascular index (CAVI) is a new index of arterial stiffness that can be measured with a VaSera VS-1000 device. An association between certain arterial stiffness indices and cardiac function has been fo... The cardio-ankle vascular index (CAVI) is a new index of arterial stiffness that can be measured with a VaSera VS-1000 device. An association between certain arterial stiffness indices and cardiac function has been found but has not yet been validated. The aim of this study was to establish whether any significant relationship exists between cardiac index (CI) and CAVI. Twenty healthy male volunteers with a mean age of 30 ± 5 years and a mean BMI of 23.1 ± 1.1 kg/m2 participated in the study. CO was estimated using a Doppler technique, and CAVI was measured with a VaSeraVS-1000 device. A motorised tilting table was used to achieve head-up tilt (HUT) angles of 0°, 30°and 60°, to modify the peripheral sympathetic outflow. We found that there was a significant inverse correlation between CI and the degree of head-up tilt, ( for 0°and 30°;for 0° and 60°, p for both;for 30° and 60°, ). CAVI showed a significant positive correlation relative with the degree of HUT, ( for 0° and 30°;for 0° and 60°;for 30° and 60°, for all). A significant negative correlation was found between CI and CAVI r = - 0.47, p Additionally, a significant p increase in PVR values was observed for increasing HUT values. In conclusion: An inverse relationship between CI and CAVI was shown;a decrease in cardiac output is associated with an increase in CAVI values at different degrees of HUT. This association provides further insight into the postural link between cardiac output and arterial compliance. 展开更多
关键词 Cardiac INDEX Cardio-Ankle VASCULAR INDEX Atherosclerosis head-up tilt
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慢性直立不耐受人群血流动力学模式与缺血性卒中发病风险关系的前瞻性研究
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作者 李贯绯 张逊娟 +1 位作者 庞猛 李淞 《吉林大学学报(医学版)》 CAS CSCD 北大核心 2024年第2期473-480,共8页
目的:探讨慢性直立不耐受(OI)人群血流动力学模式与缺血性卒中发病风险的关联,为早期评估缺血性卒中的发病提供依据。方法:以多阶段随机抽样的方法抽取吉林省长春市3个街道/乡镇≥40岁638名居民作为研究对象,经颅多普勒(TCD)联合直立倾... 目的:探讨慢性直立不耐受(OI)人群血流动力学模式与缺血性卒中发病风险的关联,为早期评估缺血性卒中的发病提供依据。方法:以多阶段随机抽样的方法抽取吉林省长春市3个街道/乡镇≥40岁638名居民作为研究对象,经颅多普勒(TCD)联合直立倾斜试验(HUTT)评估OI人群血流动力学模式,建立OI研究队列;按血流动力学改变模式将患者分为直立位低血压(OH)组、直立位高血压(OHT)组、体位性心动过速综合征(POTS)组和直立性脑低灌注综合征(OCHOs)组;对入选的研究对象每半年随访1次,随访2年;以首次缺血性卒中发病为观察终点,收集研究对象基线资料和随访期间缺血性卒中发病情况,采用Cox比例风险模型分析与缺血性卒中发病风险关联的因素。结果:121例研究对象符合OI诊断标准,其中OH组80例(66.12%),OHT组35例(28.93%),POTS组5例(4.13%),OCHOs组1例(0.82%);随访期间,总体人群确诊新发缺血性脑卒中事件共43例;在控制相关混杂因素后,以非OI者为参照,OI全人群、OH和OHT患者发生缺血性卒中的风险分别增加1.527倍[风险比(HR)=2.527,95%CI:1.269~5.032,P<0.01]、2.268倍(HR=3.268,95%CI:1.603~6.663,P=0.001)和2.153倍(HR=3.153,95%CI:1.213~8.916,P=0.008)。结论:OI与缺血性卒中发病风险增加有关,其中OH组和OHT组患者发病风险增加尤为明显。 展开更多
关键词 直立不耐受 直立位低血压 直立位高血压 缺血性卒中 经颅多普勒 直立倾斜试验
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Continuous assessment of cerebral autoregulation by TCD during tilt table testing
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作者 Xiaodong Yuan Imre Szirmai Robert Debreczeni 《华北煤炭医学院学报》 2006年第1期41-45,共5页
[SUMMARY] TTTT is a non-invasive and new investigative examination,and a most important method of clinical diagnosis for many diseases,specially for orthostatic syncope,autonomic failure,intracranial hypertension,neur... [SUMMARY] TTTT is a non-invasive and new investigative examination,and a most important method of clinical diagnosis for many diseases,specially for orthostatic syncope,autonomic failure,intracranial hypertension,neurodegenerative diseases,CVAs and so on.At the same time,TCD technique for non-invasive monitoring of CBFV has also provided a new tool for investigating CA.In clinical circumstance,we may carry on assessment of dynamic CA by TTTT,and this kind of method has been proved to be appropriate to examine patients and monitor.we can choose different tilt positions by tilt-table according to the different demands for clinical diagnosis or researches,and record the different appearances of various index signs,we can take advantage of the technique of transfer function analysis of power spectrum between spontaneous changes in CBF and other factors(such as arterial pressure) to do research on the specific mechanism of impaired CA. 展开更多
关键词 TCD 大脑 调节机制 连续治疗 实验研究
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基于经颅多普勒直立倾斜试验分析焦虑抑郁患者自主神经功能的特征
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作者 张亚雯 陈文敏 郭晓云 《河北医学》 CAS 2024年第3期493-499,共7页
目的:基于经颅多普勒(TCD)直立倾斜试验分析焦虑抑郁患者自主神经功能的特征。方法:选择2021年3月至2023年2月就诊于本院的焦虑抑郁患者80例,作为病例组,另选同期于本院体检的健康者80例,作为对照组。两组均接受TCD、直立倾斜试验与动... 目的:基于经颅多普勒(TCD)直立倾斜试验分析焦虑抑郁患者自主神经功能的特征。方法:选择2021年3月至2023年2月就诊于本院的焦虑抑郁患者80例,作为病例组,另选同期于本院体检的健康者80例,作为对照组。两组均接受TCD、直立倾斜试验与动态心电图(DCG)检查,对比两组W波回调不全发生率、直立倾斜试验血流动力学、TCD脑血流、心率变异性(HRV),Pearson相关性分析直立倾斜试验血流动力学、TCD脑血流与HRV的相关性,绘制ROC曲线分析TCD联合直立倾斜试验预测焦虑抑郁发生的价值。结果:与对照组比较,病例组W波回调不全发生率显著升高,有统计学差异(11.25%VS 0.00%,χ2=5.378,P=0.020);病例组倾斜直立位HR高于对照组,DBP、SV低于对照组(t=6.532、7.944、6.152,P均=0.000);病例组从平卧位至倾斜直立位的DBP、HR、SV变化绝对值高于对照组(t=12.015、6.644、5.635,P均=0.000);病例组倾斜直立位的Vd、Vs、Vm低于对照组,RI、PI高于对照组(t=10.488、3.927、11.256、2.298、5.918,P=0.000、0.000、0.000、0.023、0.000);病例组从平卧位至倾斜直立位的Vd、Vs、Vm、RI、PI变化绝对值高于对照组(t=9.559、10.943、10.775、10.738、28.236,P均=0.000);病例组LF、HF、PNN50、RMSSD、SDNN低于对照组(t=10.992、12.098、12.376、6.078、7.758,P均=0.000);Pearson相关性分析,从平卧位至倾斜直立位的DBP、HR、SV、Vd、Vs、Vm、RI、PI变化绝对值均与LF、HF、PNN50、RMSSD、SDNN呈负相关(r<0,P<0.05);绘制ROC曲线发现,从平卧位至倾斜直立位的DBP、HR、SV、Vd、Vs、Vm、RI、PI变化绝对值及联合预测焦虑抑郁的AUC分别为0.603、0.728、0.802、0.805、0.756、0.710、0.783、0.739、0.949。结论:TCD联合直立倾斜试验可有效预测焦虑抑郁发生,且二者可反映患者自主神经功能特征。 展开更多
关键词 焦虑抑郁 经颅多普勒 直立倾斜试验 自主神经功能
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血管迷走性晕厥手术治疗的现状与展望
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作者 贯玲儿 张海澄 《中国循环杂志》 CSCD 北大核心 2024年第1期95-99,共5页
血管迷走性晕厥作为晕厥中最常见的一种形式,心脏抑制型晕厥患者经随机临床试验证实有效的药物疗法有限,可建议使用永久性起搏器治疗。本文梳理了起搏器治疗血管迷走性晕厥中曲折发展经历并总结了原因,根据指南整理了目前适用于起搏治... 血管迷走性晕厥作为晕厥中最常见的一种形式,心脏抑制型晕厥患者经随机临床试验证实有效的药物疗法有限,可建议使用永久性起搏器治疗。本文梳理了起搏器治疗血管迷走性晕厥中曲折发展经历并总结了原因,根据指南整理了目前适用于起搏治疗的患者类型以及应用的局限性,心脏神经消融术可能成为血管迷走性晕厥患者的另一种选择,但尚需要大样本随机对照试验证实其安全性、有效性以及适用人群。 展开更多
关键词 血管迷走性晕厥 起搏器 直立倾斜试验 心脏神经消融术
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基于数字图像技术振动台试验结构位移信息捕捉技术研究
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作者 常铭宇 申玉生 +3 位作者 张熙 高登 骆阳 王浩鱇 《振动与冲击》 EI CSCD 北大核心 2024年第5期139-148,158,共11页
针对振动台试验模型箱位移、围岩错动以及隧道衬砌变形监测的需求,将YOLO-V2、改进Canny边缘检测、Hough变换及倾斜矫正技术相结合,提出了一种倾斜影像的自动矫正技术,实现了将倾斜影像修正为相机光轴垂直于测点运动平面的图像分析;提... 针对振动台试验模型箱位移、围岩错动以及隧道衬砌变形监测的需求,将YOLO-V2、改进Canny边缘检测、Hough变换及倾斜矫正技术相结合,提出了一种倾斜影像的自动矫正技术,实现了将倾斜影像修正为相机光轴垂直于测点运动平面的图像分析;提高了试验数据结果的处理精度,扩大了目标追踪算法在结构位移和变形监测的使用范围。同时通过核相关滤波技术完成对修正后的影像进行追踪,形成一套完整的地震动信号捕捉与监测系统。采用该系统进行了强震作用下穿越断层隧道韧性结构减震抗错性能试验研究,分别对模型箱位移、围岩错动和隧道衬砌变形进行信号识别与捕捉,同时对比分析了高精度拉线式位移计和位移传感器采集的数据,验证了系统的可靠性。结果表明:在监测点位设有标记物时,首先对采集结果进行倾斜矫正后追踪,通过监测结果与位移传感器进行对比,两者的2-范数小于0.005;而在无标记物时对结构表面特征物进行追踪,精度达到了97.5%;试验数据证明通过倾斜影像自动矫正技术来完成非对正对标记物时的影像进行追踪具有较高可靠性。 展开更多
关键词 振动台试验 变形监测 CANNY边缘检测 倾斜影像自动修正 目标追踪
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Dependence of single event upsets sensitivity of low energy proton on test factors in 65 nm SRAM 被引量:1
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作者 罗尹虹 张凤祁 +2 位作者 潘霄宇 郭红霞 王圆明 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第7期566-571,共6页
In order to accurately predict the single event upsets (SEU) rate of on-orbit proton, the influence of the proton energy distribution, incident angle, supply voltage, and test pattern on the height, width, and posit... In order to accurately predict the single event upsets (SEU) rate of on-orbit proton, the influence of the proton energy distribution, incident angle, supply voltage, and test pattern on the height, width, and position of SEU peak of low energy protons (LEP) in 65 nm static random access memory (SRAM) are quantitatively evaluated and analyzed based on LEP testing data and Monte Carlo simulation. The results show that different initial proton energies used to degrade the beam energy will bring about the difference in the energy distribution of average proton energy at the surface and sensitive region of the device under test (DUT), which further leads to significant differences including the height of SEU peak and the threshold energy of SEU. Using the lowest initial proton energy is extremely important for SEU testing with low energy protons. The proton energy corresponding to the SEU peak shifts to higher average proton energies with the increase of the tilt angle, and the SEU peaks also increase significantly. The reduction of supply voltage lowers the critical charge of SEU, leading to the increase of LEP SEU cross section. For standard 6-transitor SRAM with bit-interleaving technology, SEU peak does not show clear dependence on three test patterns of logical checkerboard 55H, all" 1", and all "0". It should be noted that all the SEUs in 65 nm SRAM are single cell upset in LEP testing due to proton's low linear energy transfer (LET) value. 展开更多
关键词 low energy proton energy distribution tilt angle supply voltage test pattern
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地震采集仪器倾斜测试(TILT)指标与建模温度关系分析 被引量:2
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作者 王萌 荆涛 +2 位作者 马俊欣 谷东辉 薛立武 《石油仪器》 2013年第6期46-47,52,共3页
作为408UL/428XL地震数据采集系统日检测的一个重要组成部分,倾斜度测试是我们检测测线正常与否的系统性指标。文章重点从影响倾斜度测试中建模温度与测试结果的关系出发,提出了一套专门的地震采集仪器倾斜测试指标与检波器及环境的对... 作为408UL/428XL地震数据采集系统日检测的一个重要组成部分,倾斜度测试是我们检测测线正常与否的系统性指标。文章重点从影响倾斜度测试中建模温度与测试结果的关系出发,提出了一套专门的地震采集仪器倾斜测试指标与检波器及环境的对应关系,并针对野外施工的实际情况提出了一整套关于仪器倾斜测试的现场作业指导方案。 展开更多
关键词 倾斜测试 建模温度 采集链 SN388
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血管迷走性晕厥患者晕厥先兆的影响因素分析
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作者 王佳玉 吴越阳 +1 位作者 张佳 刘杰昕 《中国卒中杂志》 2023年第11期1262-1267,共6页
目的分析血管迷走性晕厥患者的临床特点,探讨其晕厥前是否有晕厥先兆的影响因素。方法回顾性纳入2017年1月—2022年6月首都医科大学附属北京天坛医院诊治的血管迷走性晕厥患者为研究对象。采集其一般资料、直立倾斜试验结果及血流动力... 目的分析血管迷走性晕厥患者的临床特点,探讨其晕厥前是否有晕厥先兆的影响因素。方法回顾性纳入2017年1月—2022年6月首都医科大学附属北京天坛医院诊治的血管迷走性晕厥患者为研究对象。采集其一般资料、直立倾斜试验结果及血流动力学指标,采用多因素logistic回归分析探讨患者发生晕厥先兆的影响因素。结果研究共纳入血管迷走性晕厥患者1211例。根据其发生晕厥前是否有先兆症状进行分组,其中无先兆组582例(48.06%),有先兆组629例(51.94%)。有先兆组患者的年龄(t=6.006,P<0.001)、女性比例(χ^(2)=11.749,P=0.001)、BM I(t=2.562,P=0.011),以及既往有高血压(χ^(2)=12.643,P<0.001)、糖尿病(χ^(2)=9.129,P=0.003)、脑血管病(χ^(2)=4.060,P=0.044)的比例与无先兆组比较,差异有统计学意义。两组患者直立倾斜试验结果比较差异无统计学意义(χ^(2)=6.205,P=0.102)。多因素logistic回归分析发现,年龄≤60岁(OR=1.727,95%CI 1.347~2.214,P<0.001)和女性(OR=1.440,95%CI 1.122~1.847,P=0.004)是血管迷走性晕厥患者发生晕厥先兆的危险因素。结论年龄≤60岁和女性血管迷走性晕厥患者更易发生晕厥先兆,这可能与自主神经调节功能有关。 展开更多
关键词 血管迷走性晕厥 晕厥先兆 直立倾斜试验 自主神经调节功能
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非对称风-浪荷载下海上风电筒型基础的累积倾角研究
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作者 刘润 孙国栋 +1 位作者 袁宇 陈广思 《天津大学学报(自然科学与工程技术版)》 EI CAS CSCD 北大核心 2023年第6期613-622,共10页
随着筒型基础逐渐成为海上风电基础的常用形式,其在循环荷载作用下的倾角长期发展规律备受关注.基于模型试验与原型无量纲量等效的缩比尺原则,开展了不同工况风-浪荷载耦合作用下筒型基础模型试验,得到了筒型基础在循环荷载作用下的累... 随着筒型基础逐渐成为海上风电基础的常用形式,其在循环荷载作用下的倾角长期发展规律备受关注.基于模型试验与原型无量纲量等效的缩比尺原则,开展了不同工况风-浪荷载耦合作用下筒型基础模型试验,得到了筒型基础在循环荷载作用下的累积倾角发展规律.试验结果表明:影响筒型基础倾角累积速率的参数随着无量纲荷载幅值的增加而增加并与荷载的非对称性无关,部分双向非对称的风-浪耦合加载工况会导致筒型基础产生更为严重的累积倾角.当循环次数和循环荷载幅值一定时,累积倾角与表征荷载非对称性的无量纲参数呈近似线性关系.根据试验数据,建立了预测不同循环荷载条件下筒型基础累积倾角的经验公式. 展开更多
关键词 海上风力机 筒型基础 模型试验 累积倾角
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氯米帕明联合硝酸甘油激发直立倾斜试验对血管迷走性晕厥的诊断价值
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作者 黄敏虎 沈松林 +1 位作者 蔡国才 唐波 《中西医结合心脑血管病杂志》 2023年第17期3252-3257,共6页
目的:探讨氯米帕明联合硝酸甘油激发直立倾斜试验(HUTT)对血管迷走性晕厥(VVS)的诊断价值。方法:选取2020年1月—2022年10月于绵阳市第三人民医院疑诊为VVS的病人120例,随机分为硝酸甘油激发HUTT组(试验1组)、氯米帕明激发HUTT组(试验2... 目的:探讨氯米帕明联合硝酸甘油激发直立倾斜试验(HUTT)对血管迷走性晕厥(VVS)的诊断价值。方法:选取2020年1月—2022年10月于绵阳市第三人民医院疑诊为VVS的病人120例,随机分为硝酸甘油激发HUTT组(试验1组)、氯米帕明激发HUTT组(试验2组)、氯米帕明联合硝酸甘油激发HUTT组(试验3组),每组40例。选取同期60名健康者,随机分为硝酸甘油激发HUTT组(对照1组)、氯米帕明激发HUTT组(对照2组)、氯米帕明联合硝酸甘油激发HUTT组(对照3组),每组20名。比较各组试验阳性率、阳性反应出现时间、并发症发生率、去甲肾上腺素(NE)、肾素活性(RA)、血管紧张素Ⅱ(AngⅡ)、醛固酮(ALD)、催乳素(PRL)、皮质醇(Cor)水平。结果:试验3组诊断的阳性率为87.50%(35/40),各组诊断的阳性率、阳性反应出现时间比较差异均无统计学意义(P>0.05)。120例疑诊为VVS病人的并发症发生率为40.00(48/120),高于健康者的20.00%(12/60),差异有统计学意义(χ^(2)=6.669,P<0.05);试验3组并发症发生率低于试验1组、试验2组,对照3组并发症发生率低于对照1组、对照2组。各组HUTT试验后NE、RA、AngⅡ、ALD和PRL、Cor水平均高于试验前,差异均有统计学意义(P<0.05);试验3组HUTT试验后NE、RA、AngⅡ、ALD、PRL、Cor水平高于试验1组、试验2组。受试者工作特征曲线(ROC)分析显示,硝酸甘油、氯米帕明激发HUTT诊断VVS的曲线下面积(AUC)分别为0.714,0.795,硝酸甘油联合氯米帕明激发HUTT诊断VVS的AUC为0.817,诊断准确性高于硝酸甘油、氯米帕明激发HUTT。结论:对于VVS病人氯米帕明联合硝酸甘油激发HUTT阳性的敏感性高,有利于临床医生提高VVS的诊断准确率。 展开更多
关键词 血管迷走性晕厥 氯米帕明 硝酸甘油 直立倾斜试验 诊断价值
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小型多桨倾转机翼飞行器倾转过渡特性风洞试验研究 被引量:1
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作者 刘纪福 马东林 罗骏 《直升机技术》 2023年第1期29-33,40,共6页
多桨倾转机翼飞行器飞行模式多且操控复杂,尤其是倾转过渡模式,气动干扰复杂,操纵冗余,从理论上确定气动与操纵特性难度大。为了研究多桨倾转机翼飞行器倾转过渡模式的气动与操纵特性,对某小型多桨倾转机翼无人机单独机翼及整机开展了... 多桨倾转机翼飞行器飞行模式多且操控复杂,尤其是倾转过渡模式,气动干扰复杂,操纵冗余,从理论上确定气动与操纵特性难度大。为了研究多桨倾转机翼飞行器倾转过渡模式的气动与操纵特性,对某小型多桨倾转机翼无人机单独机翼及整机开展了倾转过渡模式不同机翼倾角、不同舵面角度、不同油门等状态下的吹风测力试验。根据试验数据分析了整机倾转过渡模式的操纵特性及控制原则,为多桨倾转机翼构型飞行器总体设计及倾转过渡模式操纵策略研究提供了参考。 展开更多
关键词 倾转机翼 倾转过渡 操纵特性 风洞试验
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