直立倾斜试验对不明原因晕厥的诊断价值及东莨菪碱疗效

目的 分析直立倾斜试验对不明原因晕厥的诊断价值，观察东莨菪碱对该病的临床治疗效果。方法 用直立倾斜试验对37例原因不明晕厥患者（排除心、脑和药物等因素）进行检查。结果 31例诱发出症状，其中11例在基础状态下（29.7%)，20例用异丙肾上腺素静脉滴注时（54％）。阳性反应表现为三种类型：①心脏抑制型5例；②血管抑制型6例；③混合型20例，阳性病例给予东莨菪碱10mg，3次／d，其中11例病人用药7天后直立倾斜试验未再诱发症状。结论 直立倾斜试验对不明原因晕厥的诊断是临床一种有效的诊断方法，东莨菪碱可用来防治直立倾斜试验诱发的晕厥。     

直立倾斜试验在儿童血管迷走性晕厥中的诊断价值

目的　探讨直立倾斜试验对儿童血管迷走性晕厥的诊断价值。方法对２４例不明原因晕厥的患 儿进行基础直立倾斜试验,并以１２名正常儿童作对照,在倾斜过程中动态观察心电图、血压、心率,并进行分析。结 果２４例晕厥患儿中,基础直立倾斜试验阳性１６例,而对照组为０。诊断敏感度为６７％,特异度为１００％,诊断价值 为７８％。１６例阳性反应中,心脏抑制型反应３例（１９％）,表现为心动过缓,血压无变化;血管抑制型反应９例 （５６％）,表现为血压下降,心率加快;混合型反应４例（２５％）,表现为心率、血压均有明显下降。结论基础直立倾斜试验可作为儿童血管迷走性晕厥的一种重要诊断方法。     

直立倾斜试验对血管迷走性晕厥诊断的价值

目的：探讨直立倾斜试验对血管迷走性晕厥的诊断价值。方法：40例不明原因晕厥者，进行直立倾斜试验（tilt table test,TTT)，试验全程行心电，血压监护，结果：TTT诱发晕厥16例，阳性率40％（16／40），其中基础倾斜试验诱发晕厥3例，阳性率7．5％（3／40），发生严重反应5例，占诱发晕厥者的31．2％（5／16），结论：TTT对血管迷走性晕厥具有较好的诊断价值。虽为无创检查，但严重反应并不少见，应于试验前严格筛选病人，试验中及时对症处理，减少严重重反应发生。     

直立倾斜试验对不明原因晕厥的临床应用价值

报告２０例不明原因晕厥病人和１０例无晕厥病史的对照病人直立倾斜试验的结果，认为６０°倾斜角度，持续４５分钟倾斜时间及加用异丙肾上腺素滴注倾斜试验的方案，可使半病人获得阳性结果而假阳性率较低对血管迷走性晕厥的机制，诊断和治疗可能性作了讨论。     

直立倾斜试验对不明原因晕厥的诊断价值及东莨菪碱疗效

目的　分析直立倾斜试验对不明原因晕厥的诊断价值 ,观察东莨菪碱对该病的临床治疗效果。方法　用直立倾斜试验对 3 7例原因不明晕厥患者 (排除心、脑和药物等因素 )进行检查。结果　 3 1例诱发出症状 ,其中 11例在基础状态下(2 9 7% ) ,2 0例用异丙肾上腺素静脉滴注时 (5 4% )。阳性反应表现为三种类型 :①心脏抑制型 5例 ;②血管抑制型 6例 ;③混合型 2 0例 ,阳性病例给予东莨菪碱 10mg ,3次 /d ,其中 11例病人用药 7天后直立倾斜试验未再诱发症状。结论　直立倾斜试验对不明原因晕厥的诊断是临床一种有效的诊断方法 ,东莨菪碱可用来防治直立倾斜试验诱发的晕厥。     

倾斜试验诊断血管迷走神经晕厥的护理配合

血管迷走性晕厥也称为神经心脏性晕厥，约占晕厥发作总数的40％，直立倾斜试验是诊断血管迷走性晕厥最有效的方法和金标准。我院于2006年7月～2007年6月对晕厥住院35例患者行倾斜试验，现将其护理配合体会介绍如下。     

舌下含化硝酸甘油直立倾斜试验对儿童不明原因晕厥的诊断研究

本文探讨了舌下含化硝酸甘油直立倾斜试验对不明原因晕厥患儿的诊断价值。研究中对 2 5例不明原因晕厥的患儿 (晕厥组 )及 10例无晕厥史的正常健康儿童 (对照组 )先行基础直立倾斜试验 ,阴性者再行舌下含化硝酸甘油直立倾斜试验 (4～ 6μg/kg,最大量不超过 30 0μg)。结果显示基础直立倾斜试验在晕厥组的阳性率为 4 8% (12 / 2 5 ) ,对照组为 0 ;舌下含化硝酸甘油直立倾斜试验在晕厥组阳性率为 80 % (2 0 / 2 5 ) ,对照组为 2 0 % (2 /10 ) ;舌下含化硝酸甘油直立倾斜试验诊断的敏感度、特异度及诊断价值均为 80 %。两组患儿中仅有 1例在试…     

直立倾斜试验在儿童不明晕厥中应用

目的探讨直立倾斜试验(HUTT)在儿童不明原因晕厥诊断中的价值。方法对2005年1月至2010年10月南阳市第二人民医院儿科门诊不明原因晕厥患儿36例及对照组正常儿童20例进行直立倾斜试验。结果直立倾斜试验阳性率在两组间差异显著。结论直立倾斜试验对不明原因晕厥患儿有较高的诊断价值。     

倾斜试验诊断血管迷走性晕厥的临床研究

倾斜试验是通过调整倾斜床,使受试者被动倾斜,从而用来激发和诊断血管迷走性晕厥(VVS)的一项实用技术。本文对1995年12月至1999年12月在我院就诊的36例原因不明晕厥病人进行直立倾斜试验(TTT),现分析报告如下。     

直立倾斜试验对血管迷走神经性晕厥的诊断价值

目的　探讨直立倾斜试验对血管迷走性晕厥的诊断价值及其局限性。方法　对 12 9例不明原因晕厥患者及 5 4名无晕厥病史健康对照者进行直立倾斜试验 ,先进行基础倾斜试验 (倾斜 70°、持续 30 min) ,阴性者再进行两阶段的异丙肾上腺素的激发试验。结果　 112 9例晕厥患者中 ,倾斜试验阳性者 88例 (阳性率 6 8.2 % ) ,5 4名对照组中阳性者 6名 (阳性率 11.1% ) ,晕厥组阳性率明显高于对照组 ,差异有显著性 (P<0 .0 0 5 )。本次试验的灵敏度 6 8.2 % ,特异度 88.9%。 2患者年龄越大阳性反应率越低 (P<0 .0 5 ) ,性别对试验的阳性反应率影响不显著 (P=0 .31)。结论　倾斜试验设备简单、易于操作、是血管迷走性晕厥的一项比较安全有效的诊断方法。     

98例小儿晕厥的临床分析

目的 探讨小儿晕厥的病因及美托洛尔治疗小儿血管迷走性晕厥（VVS）的疗效,为临床诊治提供依据.方法 采用卧位立位血压、血常规、血糖浓度、血气分析、心电图、超声心动图、头颅CT、脑电图、24h动态心电图以及直立倾斜试验（HUT）等检测指标,以鉴别得病的原因;将VVS患儿随机平均分为治疗组（口服美托洛尔片）及对照组（口服复合维生素B片）,观察两组患者临床晕厥发作次数及HUT结果.结果 小儿自主神经介导晕厥发病率最高（64.3％）,其中VVS晕厥发病最多（66.7％）.治疗组经美托洛尔治疗后有效率为85.7％,HUT阴转率为66.7％;对照组有效率为42.8％,HUT阴转率为44.4％;两组有效率差异有统计学意义（P＜0.05）.结论 小儿自主神经介导晕厥发病率最高,尤其以VVS晕厥最多见;口服美托洛尔片可有效治疗小儿VVS晕厥.     

A review of pathophysiology and therapy of patients with vasovagal syncope

Vasovagal syncope is a common disorder that can compromise quality of life and lead to significant morbidity. It is characterized by an initial exaggerated sympathetic output followed by parasympathetic activation and sympathetic withdrawal, as shown by diagnostic head-up tilt (HUT) table testing. Numerous drugs have been evaluated for treating this disorder. beta-Blockers are well studied and commonly administered but are specifically more efficacious in patients with isoproterenol HUT than in those with regular HUT. The role of the serotonergic system has captured new interest. Selective serotonin reuptake inhibitors show promising results in preventing vasovagal syncope in treatment-refractory patients. Also, new investigations suggest that serotonin receptor antagonism may be beneficial. Despite these findings, definitive treatment does not exist.     

Baroreceptor reflexes in postural control of circulation in rabbits

The present study was undertaken to evaluate reflex cardiovascular responses to postural stress in rabbits. The changes in mean arterial pressure (MAP) and heart rate (HR) were monitored in the supine position and following sudden passive head up tilt (HUT), and head down tilt (HDT) to 70 degrees. The results show a significant increase in MAP (18.57%, P less than 0.001) and HR (2.92%, P less than 0.02) with HUT; and a marked decrease in MAP (43.48%, P less than 0.001) and HR (8.21%, P less than 0.001) with HDT (as compared to the values in supine position). The changes in MAP were found to be more marked than those in HR. The depressor responses to HDT were more marked than the pressor responses to HUT.     

倾斜试验鉴别运动试验结果阴性患者运动后晕厥

目的为了探讨直立倾斜试验（TTT）对活动平板运动试验结果阴性患者运动后晕厥的鉴别诊断价值以及运动后晕厥的临床意义。方法 活动平板运动试验结果阴性的运动后晕厥患者,均进行TTT。结果186例运动后晕厥患者有141例在TTT中出现阳性,阳性率75.81％,且以男性（102／141）、血管抑制性晕厥（106／141）患者占大多数;其中出现在基础倾斜试验（BTTT）中22例,阳性率11．83％;出现在异丙基肾上腺素倾斜试验（ITTT）中119例,阳性率63．98％。结论运动后晕厥多属血管迷走性,TTT是鉴别活动平板运动试验结果阴性患者运动后晕厥的首选方案。     

Strategic self-regulation, decision-making and emotion processing in poly-substance abusers in their first year of abstinence

Individuals with substance dependence (ISD) frequently show signs of impaired emotion processing, self-regulation and decision-making, even after prolonged abstinence from drug use and partial recovery of other neuropsychological functions. These impairments have been associated with alterations in the orbitofrontal cortex (OFC) in lesion and imaging studies. The aim of this study was to examine the performance of a group of ISD, who had been abstinent for at least 4 months, on a series of emotional perception, self-regulation and decision-making tests sensitive to OFC dysfunction. Thirty ISD (poly-substance abusers in their first year of abstinence) and 35 healthy comparison (HC) participants were in the study. We administered the Ekman Faces Test (EFT), the Revised Strategy Application Test (R-SAT) and the Iowa Gambling Task (IGT) to both ISD and HC. Results showed that the ISD presented significant deficits in the recognition of facial emotional expressions and decision-making as measured by the EFT and the IGT. The ISD also showed poorer strategy awareness, impaired self-regulation and higher impulsivity on the R-SAT. We found significant correlations between the different measures linked to OFC functioning. We did not find significant correlations between length of abstinence and performance on these tests. These results suggest that the evaluation of emotion, self-regulation and decision-making contributes greatly to the characterization of the persistent deficits exhibited by ISD during prolonged abstinence.     

Tilt table testing in the diagnostic evaluation of presyncope and syncope: a case-series report

Tilt table testing has long been used as a standard tool in the diagnostic evaluation of syncope. However, differences of opinion exist with regard to its utility in the evaluation of patients with only presyncopal attacks. We present the results of drug-free, 70-degree head-up tilt table tests (maximum duration of 45 minutes), conducted between May 2002 and May 2003 in the Department of Physiology at JIPMER. This series consisted of both male and female patients (age 6-79 yr) with presyncope (n = 43), unexplained syncope (n = 43) and asymptomatic healthy volunteers without a history of syncope (n = 14). 28 out of 43 patients with unexplained syncope had a history of recurrent syncope while the remaining 15 had only 1 episode. 2 out of 43 patients (4.6%) with a history of only presyncopal attacks had a positive test (induction of intense presyncope and/or syncope accompanied by hypotension and/or a relative bradycardia). 21 out of 43 patients (49%) with a history of syncope had a positive test. 7 had vasodepressor syncope due to hypotension, 6 had cardioinhibitory syncope characterized by asystole and 10 had a mixed form of the vasovagal syndrome characterized by hypotension as well as bradycardia. 18 out of 28 patients (64%) with recurrent unexplained syncope had a positive test. All fourteen healthy volunteers had a negative test. We conclude that tilt table testing is useful in the diagnostic evaluation of patients with unexplained syncope, especially those with recurrent syncope, but not in the evaluation of patients with presyncope alone.     

Effect of head-up tilt on cardiovascular responses in normal young volunteers

Since the cardiovascular effects of tilting are influenced by degree as well as duration of the tilt, we planned to study the time course of blood pressure and heart rate (HR) responses during 30 degrees, 60 degrees, 80 degrees head up tilt (HUT). The study was conducted on 20 volunteers aged 18-20 y who were tilted on a tilting table. Blood pressure was determined by sphygmomanometer and HR was calculated from R-R interval of ECG. 30 degrees HUT produced an insignificant decrease in systolic pressure (SP) and pulse pressure (PP) while diastolic pressure (DP), mean pressure (MP) and rate-pressure-product (RPP) registered an insignificant rise. The changes produced by 60 degrees and 80 degrees HUT were more marked than those produced by 30 degrees HUT. While SP and PP decreased significantly, HR and RPP increased significantly. In conclusion, 30 degrees HUT produces insignificant changes while 60 degrees and 80 degrees HUT produce significant changes in SP, PP and RPP.     

Biotransformation of organic nitrate esters in vitro by human liver, kidney, intestine, and blood serum

The biotransformation of glycerol trinitrate (GTN), isosorbide dinitrate (ISD), pentaerythritol tetranitrate (PETN), erythritol tetranitrate (ETN), and mannitol hexanitrate (MHN) by extracts from human liver, small intestine mucosa, kidney, and blood serum was investigated. The glutathione-dependent organic nitrate ester reductase activity of the intestinal mucosa was 21, 4, 4, and 2 times higher than the liver activity for ISD, PETN, GTN, and ETN, respectively. The liver enzymatic activity for MHN was 35% higher than the intestinal activity and 56% higher than kidney enzyme activity. The order of increasing enzymatic rates was: ISD = PETN less than GTN less than ETN less than MHN in the intestinal mucosa; ISD less than PETN less than GTN less than ETN less than MHN in the liver; and ISD less than PETN = GTN less than ETN less than MHN in the kidney. Human serum also metabolized these organic nitrates at lower rates than the studied organs. Thus, the serum specific activities were 1/5 for MHN, 1/30 for ETN, 1/40 for GTN, 1/44 for ISD, and 1/2000 for PETN of the activity present in kidney. On the other hand, the activity of human albumin was lower than that of blood serum. The serum and albumin activities were not modified by reduced glutathione or sulfhydryl inhibitors. These results suggest that small intestine may play an important role in the biotransformation of these drugs at their absorption site, after oral administration. They also demonstrate the possible participation of various human tissues in the overall metabolism of organic nitrate esters.     

非心源性晕厥住院患儿18例临床分析

目的分析非心源性晕厥住院患儿的发病情况及病因。方法回顾分析近10年来住院治疗的18例非心源性晕厥住院患儿临床资料。结果18例患儿年龄在8～14(10.6±1.3)岁,男性7例,女性11例。脑源性晕厥6例,占33.3%,包括癫痫1例,脑震荡1例,颅内基底动脉供血不足4例;精神心理性晕厥—癔症2例,占11.1%;血液成分异常晕厥—月经失血性贫血1例,占5.6%;不明原因晕厥9例,占50.0%。结论非心源性晕厥住院患儿以学龄期女性多见,多表现为反复发作性晕厥或伴抽搐、或诊断不能及时明确者,以不明原因晕厥发生率最高,但青少年女性也可因严重的月经失血性贫血导致晕厥。一般预后较好,但不明原因晕厥多次频繁发作也易造成意外,或引发严重心律失常危及生命,故应加强随访。