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。     

异丙肾上腺素倾斜试验并发阿斯综合征2例

晕厥的原因较多 ,其中血管迷走性晕厥所占比例很高 ,可达 5 0 %以上[1] 。倾斜试验可诱发血管迷走性晕厥 ,是诊断血管迷走性晕厥的有效的、无创性的检查手段 ,一般认为这种检查较为安全。在我院 ,因不明原因晕厥进行倾斜试验的 10 0多例患者中 ,有 2例在晕厥发作时伴有严重缓慢     

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。     

50例直立倾斜试验结果的分析

目的：探讨直立倾斜试验作为对反复发作不明原因晕厥患者的一种评估手段。为临床迷走神经性晕厥患者的诊断提供有效的依据。方法选取50例不明原因晕厥患者（排除心、脑疾病）在安静环境下空腹做直立倾斜试验,持续检测心电和血压,观察血压及心电变化。结果50例不明原因晕厥的患者出现血管迷走反应者有34例（68%）,其中血管抑制型9例（18%）,心脏抑制型的4例（8%）,混合型的21例（42%）。结论不明原因晕厥患者在直立倾斜试验中以经典血管迷走反应者占多数,为诊断血管迷走型晕厥提供依据。     

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。     

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。     

直立倾斜试验的时间对不明原因晕厥患者诊断结果影响分析

目的研究进行直立倾斜试验时不同时间对不明原因晕厥患者诊断结果的影响。方法对1290例不明原因晕厥患者进行基础倾斜试验及药物激发试验。其中一组基础时间为45min,药物试验时间为20min(A组),另一组基础时间为30min,药物为10min(B组),观察两组试验阳性率。结果 A组中血管迷走性晕厥336例(51.9%),直立性低血压94例(13.9%);B组中血管迷走性晕厥324例(50.4%),直立性低血压96例(14.9%),两组阳性率相似(51.9%与50.4%,P>0.05)。结论 2组不同时间直立倾斜试验方法对不明原因的晕厥患者诊断阳性率没有明显差异。     

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。     

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。     

直立倾斜试验对心脏神经反射性晕厥诊断和治疗价值的评价

采用多阶段异丙基肾上腺素直立倾斜试验（ＭＩＴＴＴ），对３６例不同明原因的晕厥患者进行研究。试验结果２８例呈阳性，阳性率为７７．８％，表现类型：混合型２３例占８２１％，血管抑制型４例占１４．３％，心脏抑制型１例占３．６％，对试验阳性反应病人给予心得安１０￣１５ｍｇ ３次／日或倍他乐克２５￣５０ｍｇ ２次／日，服药２￣３周，治疗后重复本试验均为阴性。随访３￣１８个月，无１例再发晕厥。     

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。     

舌含消心痛直立倾斜试验对血管迷走性晕厥诊断价值探讨：附22例分析

我们对８名不明原因晕厥病人及１４名对照者经基础直立倾斜试验后，进行舌下含服消心中加直立倾斜试验。Ｓ．ＩＳＤ－ＨＵＴ在诱发血管迷走性晕厥病人的敏感性为７１％，特异性为９２％。     

Effects of orthostatic self-training on head-up tilt testing and autonomic balance in patients with neurocardiogenic syncope

To investigate the effectiveness and the mechanisms of an orthostatic self-training program for the prevention of neurocardiogenic syncope, 28 patients were treated with an orthostatic self-training program. Syncope was induced by head-up tilt testing (+ 80 degrees for 30 min) in all patients. The onset time of the tilt-induced syncope was 14 +/- 7 min following placement in the upright position. The orthostatic self-training program included standing against a wall without moving twice a day every day for a planned duration of up to 30 min at home. The head-up tilt response was re-evaluated after 24 +/- 6 days based on results of the self-training. In 12 of the 28 patients, the sympathovagal balance was also determined during the head-up tilt test before and after the training with power spectral analysis of heart rate variability using a maximal entropy method. Syncope was not observed in any patient after the training. Although the low frequency/high frequency ratio in the supine position was not different before and after the training, the ratio after 3 min in the upright position after the training decreased significantly compared with that before the training. High-frequency components in the supine and upright positions were not different before and after the training. We concluded that orthostatic self-training significantly improved symptoms in patients with tilt-induced neurocardiogenic syncope. Decreased sympathetic activity in the early stage of the upright position period may play an important role in the mechanisms of this therapy.     

Strategy for the management of vasovagal syncope

The disorders of autonomic control associated with orthostatic intolerance are a diverse group of syndromes that can result in syncope and near-syncope. A basic understanding of the pathophysiology of these disorders is essential to diagnosis and proper treatment. It is especially important to recognise the difference between the effect of prolonged upright posture on a failing autonomic nervous system (a hyposensitive or dysautonomic response) and the vasovagal response (which may be a hypersensitive response). Vasovagal syncope is the most common abnormal response to upright posture and occurs in all age groups. The advent of tilt table testing has helped define a population with an objective finding during provocative testing that has enabled researchers to study the mechanism of vasovagal syncope and to evaluate the efficacy of treatments. In most patients, vasovagal syncope occurs infrequently and only under exceptional circumstances and treatment is not needed. Treatment may be indicated in patients with recurrent syncope or with syncope that has been associated with physical injury or potential occupational hazard. Based on study data, patients with vasovagal syncope can now be risk stratified into a high-risk group likely to have recurrent syncope and a low-risk group. Many patients with vasovagal syncope can be effectively treated with education, reassurance and a simple increase in dietary salt and fluid intake. In others, treatment involves removal or avoidance of agents that predispose to hypotension or dehydration. However, when these measures fail to prevent the recurrence of symptoms, pharmacological therapy is usually recommended. Although many pharmacological agents have been proposed and/or demonstrated to be effective based on nonrandomised clinical trials, there is a remarkable absence of data from large prospective clinical trials. Data from randomised placebo-controlled studies support the efficacy of beta-blockers, midodrine, serotonin reuptake inhibitors and ACE inhibitors. There is also considerable clinical experience and a consensus suggesting that fludrocortisone is effective. Encouraging new data suggest that a programme involving tilt training can effectively prevent vasovagal syncope. For patients with recurrent vasovagal syncope that is refractory to these treatments, implantation of a permanent pacemaker with specialised sensing/pacing algorithms appears to be effective. A number of larger clinical trials are underway which should help further define the efficacy of a number of different treatments for vasovagal syncope.     

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.     

Neurocardiogenic syncope: aetiology and management

Neurocardiogenic syncope is the most common cause of syncope presenting in the outpatient setting. It is usually encountered among individuals without an underlying heart disease, but not uncommonly participates in the syncope mechanism of patients with an obstructive or an arrhythmic cardiac cause for syncope as well. The vasovagal event is caused by a transient profound hypotensive reaction most commonly associated with inappropriate bradycardia resulting from activation of a complex autonomic reflex. The pathophysiology of neurocardiogenic syncope has been elucidated by tilt table testing, a noninvasive and well-tolerated method for reproducing the event in susceptible individuals. Although the majority of people with vasovagal fainting need no specific treatment, treatment is required for those presenting with problematic features such as frequent events accompanied by trauma or accidents, and occasionally by a severe cardioinhibitory pattern response. A number of different drugs have been proposed to favourably act on different aspects of the neurocardiogenic reflex but only a few randomised, placebo-controlled, drug-specific trials are currently available. Alternatively, cardiac pacing has also been introduced for patients who have symptoms that are drug-refractory or for those with a severe cardioinhibitory hypotensive response. The selection of the appropriate treatment plan should be individualised after consideration of patient history, clinical characteristics and preference, results of the baseline tilting study, and the existing evidence from the few randomised, controlled studies performed so far.