倾斜试验对原因不明晕厥诊断价值的探讨

对２１例原因不明晕厥患者（晕厥组）行倾斜试验并以正常人作对照（正常对照组）。晕厥组基础倾斜试验阳性９例（４２．９％），多阶段异丙肾上腺素－倾斜试验阳性１０例（８３．０％），总阳性率为９０．５％（１９／２１）。对照组基础倾斜试验无一例阳性，与晕厥组比较，Ｐ＜０．００１；多阶段异丙肾上腺素－倾斜试验有２例为阳性，假阳性率１０％。结果显示：倾斜试验采用倾斜８０°、持续４５ｍｉｎ、异丙肾上腺素用量为４～６μｇ／ｍｉｎ，对不明原因晕厥的诊断，其敏感性为９０．５％、特异性为９０％、准确性为９０．２％。倾斜试验是诊断血管迷走性晕厥、指导临床治疗的一种有价值的方法。     

异丙肾上腺素直立倾斜试验的重复性

为观察直立倾斜试验（ＴＴＴ）的重复性如何？对５７例不明原因晕厥患者（研究组）和１３例健康人（对照组）采用基础倾斜试验（ＢＴＴＴ）＋异丙肾上腺素倾斜试验（ＩＴＴＴ）的方法，间隔２４小时分别行两次ＴＴＴ。结果显示：（１）研究组５７例，第一次ＢＴＴＴ诱发血管抑制性晕厥１３例（２２．８％），其中９例（６９．２％）次日ＢＴＴＴ仍诱发血管抑制性晕厥；ＴＴＴ阴性４４例，次日４２例仍ＴＴＴ阴性（９５．５％）。ＢＴＴＴ＋ＩＴＴＴ分别诱发血管抑制性晕厥２９例（５０．９％）、体位性低血压７例（１２．３％），次日仍可诱发相同表现者分别为２２例（７５．９％）和４例（５７．１％）；ＴＴＴ阴性２１例，次日１７例仍阴性（８１．０％）。两次均ＴＴＴ阳性者病史中曾经发生晕厥平均１０．０±１６．０次；第一次检查阳性，第二次阴性者为２．８±２．３次，差异有显著性（Ｐ＜０．０５）。（２）对照组１３例，１例ＩＴＴＴ诱发血管抑制性晕厥，不能重复。提示ＴＴＴ阳性者重复性稍差，合用异丙肾上腺素虽不使血管抑制性晕厥者隔日重复性降低，但体位性低血压诱发率明显增加，用于评价疗效需慎重。     

自主神经在血管迷走性晕厥发病中的作用

目的探索自主神经系统如何介导血管迷走性晕厥的发生。方法对９４例不明原因晕厥的病人进行了倾斜试验。倾斜过程中动态监测心电图、血压和心率。进行心率变异性分析。结果４４例发生晕厥，其中基础倾斜试验晕厥３２例，阳性率３４．０％；异丙肾上腺素晕厥１２例，阳性率增加１２．８％。晕厥时ＬＦ及ＨＦ明显下降，ＶＬＦ明显升高。结论（１）血管迷走性晕厥时，交感神经和迷走神经张力受抑制，导致血管扩张，血压下降。（２）ＶＬＦ的升高与ＬＦ的下降明显相关。ＶＬＦ升高的意义有待深入研究     

直立倾斜试验诊断不明原因晕厥的临床价值

以５８例不明原因晕厥患者及２０例无晕厥史的正常人（对照组）进行了直立倾斜试验（ＴＴＴ）。结果观察组阳性４２例９其中基础试验阳性９例，倾斜加异丙肾上腺素试验阳性３３例），阳性率为７２．４％；对照组仅１例阳性，两组比较有非常显著性差异，观察组试验一的４２例中，晕厥表现为心脏抑制型４例，血管抑制型８例，混合型３０例，提示（１）ＴＴＴ对诊断血管迷走性晕厥有重要价值（２）血管迷走性晕厥以混全型多见（７２．４     

倾斜试验诱发血管迷走性晕厥56例分析

目的　探讨血管迷走性晕厥时血压,心率变化,从而了解自主神经系统所起的作用。方法　对９０ 例不明原因晕厥患者进行倾斜试验,试验过程动态监测心电图、血压和心率。结果　５６ 例发生晕厥,其中基础倾斜试验晕厥４ 例,阳性率４－４ ％ ,异丙肾上腺素倾斜试验晕厥５２ 例,阳性率５７－８％ ,其中异丙肾上腺素浓度为２ μｇ／ｍｉｎ、４ μｇ／ｍｉｎ 各２８－９％ 。晕厥时收缩压下降（４５－６６ ±２２－４６）ｍｍＨｇ,舒张压下降（２９－１１ ±１１－１４）ｍｍＨｇ,心率下降。结论　血管迷走性晕厥时血压显著下降,心率下降,提示交感神经活动减弱为主,可伴迷走神经活动增加。     

倾斜试验诊断不明原因晕厥的方法学评价

８４例不明原因晕厥的病人及５０例无晕厥病史的正常人对照，各分成三组，分别采用基础倾斜试验（ＢＴＴＴ）、多阶段异丙肾上腺素倾斜试验（ＭＩＴＴＴ）、单阶段异丙肾上腺素倾斜试验（ＳＩＴＴＴ）。三组的年龄、性别以及晕厥指数差异均无显著性（Ｐ＞０．０５）。结果：（１）ＢＴＴＴ组，病人的血管迷走性晕厥（ＶＳ）阳性诱发率为３８％（１４／３７），正常对照无一例阳性（０／２５）；ＭＩＴＴＴ组，病人及正常对照的阳性率分别为７４％（２０／２７）及２５％（３／１２）；ＳＩＴＴＴ组，分别为７０％（１４／２０）及５４％（７／１３）。（２）三组病人中，诱发晕厥所需的时间分别为１６．７３±８．５８ｍｉｎ，５．６９±３．５３ｍｉｎ、３．７３±２．８２ｍｉｎ、三组病人的实验平均时程分别为３９．６６±１４．２７ｍｉｎ、３８．５０±８．１４ｍｉｎ、１１．０５±４．１７ｍｉｎ。结果提示：（１）加用异丙肾上腺素可明显提高倾斜试验的敏感性、但特异性相应降低；（２）加用异丙肾上腺素可明显缩短诱发晕厥的时间；（３）ＢＴＴＴ的敏感低，ＳＩＴＴＴ的特异性低，而ＭＩＴＴＴ的诊断价值最高，建议作为常规方法推广，而ＢＴＴＴ及ＳＴＴＴ仅作为特殊情况下选用。     

多阶段倾斜试验在晕厥患者的临床研究

为了解倾斜试验在不明原因晕厥中的临床意义，对３５例不明原因晕厥患者和２０例窦性心动过缓（窦缓）患者采用多阶段倾斜试验（ＭＩＴＴＴ），观察了４个阶段试验结果。结果显示：３５例晕厥患者中阳性２８例，阴性７例，阳性率为８０％。２０例窦缓患者中阳性２例，阴性１８例，阳性率为１０％。两组之间差异有极显著性（Ｐ＜０．００１）。倾斜试验合用异丙肾上腺素可提高阳性率。９５％的阳性患者在异丙肾上腺素剂量（≤３μｇ／ｍｉｎ）５分钟内出现阳性结果。心率－血压乘积值显著下降有助于鉴别阳性或阴性结果。其阳性预测值≤１．２×１０３ｋＰａ／ｍｉｎ（１ｋＰａ＝７．５ｍｍＨｇ），阴性预测值≥１．３×１０３ｋＰａ／ｍｉｎ。提示ＭＩＴＴＴ有较高的诊断价值，建议作为常规方法推广。     

倾斜试验诱发血管迷走性晕厥的反应及有关机制探讨

为探讨倾斜试验诱发血管迷走性晕厥的反应及有关机制，对１１０例不明原因晕厥患者及３７例正常人观察倾斜试验（ＴＴＴ）时血管迷走性反应。结果显示：ＴＴＴ阳性、阴性及正常对照组之间基础舒张压（ＤＢＰ），基础心率×ＤＢＰ差异均无显著性，而ＴＴＴ阳性病人晕厥即刻ＤＢＰ，ＤＢＰ×心率与基础状态各指标比较，差异则有显著性，但晕厥即刻心率和基础心率比较，差异无显著性，说明血管迷走性晕厥（ＶＳ）的反应以血压变化为主为先，心率变化较迟或不明显，提示ＢＰ和心率的变化并非同一机制所致。ＴＴＴ阳性病人中异丙肾上腺素激发者占７０％，反映了ＶＳ的发生可能与β－受体高敏感性有关。ＴＴＴ的应用为研究ＶＳ的发病机理提供了手段。     

硝酸甘油与异丙肾上腺素直立倾斜试验诊断血管迷走性晕厥对比研究

目的:比较舌下含服硝酸甘油与静脉泵入异丙肾上腺素直立倾斜试验诊断血管迷走性晕厥的价值。方法:回顾性分析我院行直立倾斜试验的326例患者。其中行基础加舌下含服硝酸甘油直立倾斜试验129例(硝酸甘油组),行基础加静脉泵入异丙肾上腺素直立倾斜试验197例(异丙肾上腺素组),比较两种药物直立倾斜试验阳性率、诱发阳性反应时间、血压心率变化和不良反应。结果:硝酸甘油组阳性率高于异丙肾上腺素组(46．9％vs 30．7％,P<0．01)。硝酸甘油组诱发阳性反应时间(7．8±3．6)分钟高于异丙肾上腺素组(5．6±1．5)分钟,但无显著差异(P>0．05),而总试验时间硝酸甘油组明显短于异丙肾上腺素组[(37．8±3．6)分钟vs(72．6±7．3)分钟,P<0．01]。硝酸甘油组不良反应发生率较异丙肾上腺素组低(0．9％vs 11．7％,P<0．01)。结论:硝酸甘油直立倾斜试验有较高的阳性率,操作方便,完成试验时间短,不良反应少。     

直立倾斜实验对晕厥患者的临床诊断价值--附110例病例分析

目的 了解直立倾斜实验对晕厥患者诊断的临床价值。方法 对110例不明原因晕厥患者进行直立倾斜实验的结果进行回顾性研究。结果 110例患者中阳性79例，占71．82％；基础实验阳性20例，占18．18％；异丙肾上腺索诱发阳性59例，占53．64％。79例阳性患者中晕厥后心率、收缩压乘积≤9000mmHg．次／min者72例，占91．14％。结论 (1)直立倾斜实验对血管迷走性晕厥的诊断有重要价值；(2)加用异丙肾上腺素可提高实验的阳性率；(3)心率、收缩压乘积有助于判断阳性结果；(4)直立倾斜实验可以作为诊断血管迷走性晕厥的首选方法。     

Atrioventricular Dissociation Exacerbating Posturally-Induced Syncope

We report a case of an 85-year-old patient with posturally-induced syncope in whom symptoms were reproduced during tilt table testing in conjunction with development of an accelerated junctional rhythm with isorhythmic atrio-ventricular (AV) dissociation. That loss of AV synchrony was crucial to development of hypotension and syncope was demonstrated during electrophysiologic testing in which both an accelerated junctional rhythm and an inducible atypical AV nodal re-entrant tachycardia (AVNRT) were induced. The accelerated junctional rhythm was accompanied by moderate hypotension with the patient in the supine posture, whereas blood pressure was well maintained during atypical AVNRT despite a much faster ventricular rate. Thus, symptomatic hypotension due to AV dissociation, presumably the result of transient autonomic disturbance, may be another manifestation of neurally-mediated syncope.     

Methodology of isoproterenol-tilt table testing in patients with syncope.

To assess the impact of isoproterenol, duration of tilt, symptom development and hemodynamic changes on the outcome of tilt table tests, 100 patients with syncope underwent successive 80 degrees head-up tilt for 10 min during infusions of 0, 2 and 5 micrograms/min of isoproterenol. All 15 patients with another cause of syncope had a normal test result and 66 (78%) of the 85 patients with syncope of unknown origin had a test that resulted in syncope or presyncope. Isoproterenol was required to produce syncope or presyncope in greater than 90% of positive tests and 66% to 80% of positive tests required a dose of 5 micrograms/min of isoproterenol. Without isoproterenol, symptoms did not develop until after greater than or equal to 4 min of head-up tilt. With either 2 or 5 micrograms/min of isoproterenol, the half-time of symptom onset was 0.7 to 1.9 min and the rate of symptom development did not depend on the dose of isoproterenol. During syncope, the mean heart rate, systolic blood pressure and rate-pressure product each decreased significantly from 132 +/- 21 to 67 +/- 25 beats/min, 117 +/- 19 to 60 +/- 16 mm Hg and 15.3 +/- 2.9 to 4.2 +/- 2.2 x 10(3) mm Hg/min, respectively. During presyncope, mean trough rate-pressure product (5.5 +/- 2 x 10(3) mm Hg/min) was significantly higher (p = 0.027) than during syncope.(ABSTRACT TRUNCATED AT 250 WORDS)     

影响倾斜试验结果的多因素分析

９２例不明原因晕厥病人及５２名无晕厥病史的正常人对照分为三组，分别采用基础倾斜试验（ＢＴＴＴ）、多阶段异丙肾上腺素─—倾斜试验（ＭＩＴＴＴ）及单阶段异丙肾上腺素─—倾斜试验（ＳＩＴＴＴ）。以实验结果为因变量，以晕厥指数、性别、年龄、基础心率、基础血压及倾斜前心率与基础心率的差值（心率差）为自变量作Ｌｏｇｉｓｔｉｃｓ回归分析。结果：①对所有受试者作Ｌｏｇｉｓｔｉｃｓ回归，晕厥指数及心率差是影响结果的主要因素（Ｐ＝０．０１２和Ｐ＝０．００１）；②病人组结果与上类似（Ｐ＝０．０５２和Ｐ＝０．０３２）；③正常对照，心率差及性别是预测结果的指标。本组结果提示：①晕厥（或先兆）的发病次数及程度以及异丙肾上腺素的应用是影响实验结果的主要因素；②异丙肾上腺素在增加敏感性的同时也增加了假阳性率；③性别也可能是影响倾斜试验（ＴＴＴ）结果的因素之一。     

Significance of tilt table testing in patients with suspected arrhythmic syncope and negative electrophysiologic study

BACKGROUND: The diagnostic significance of a tilt table test (TTT) in patients with a suspected arrhythmic etiology for syncope and negative electrophysiologic study (EPS) has not been previously assessed comparing the TTT results with the findings of prolonged monitoring using an implantable loop recorder (ILR). We sought to assess the diagnostic yielding of TTT in patients with suspected arrhythmic syncope and negative EPS. METHODS AND RESULTS: In 81 patients with suspected arrhythmic etiology for syncope and negative EPS, TTT was performed and an ILR implanted regardless the results of TTT. TTT was positive in 38 patients. During follow-up, syncope or presyncope recurred in 32 patients (39.5%). No differences were found in recurrence rates in patients with positive and negative TTT (31.5% vs 46.5%, P = ns). According to rhythm registered during ILR activation, mechanisms of syncopal events were classified as: arrhythmic (atrioventricular [AV] block and ventricular tachycardia; n = 18), neurally mediated (sinus bradycardia and sinus pause; n = 9), and indeterminate (normal sinus rhythm; n = 5). There was no statistical association between the results of TTT and the mechanism of syncope. CONCLUSIONS: In patients with a suspected arrhythmic etiology for syncope and a negative EPS, TTT is of little value to predict the mechanism of syncope and the ILR implantation seems to be a useful and safe diagnostic strategy.     

直立倾斜试验阳性反应出现后的心律失常特征

目的 探讨直立倾斜试验(HUTT)阳性反应出现后患者心律失常发生的特征.方法 分析2001年3月至2009年8月在基础直立倾斜试验(BHUT)或舌下含化硝酸甘油倾斜试验(SNHUT)阳性反应出现后发生心律失常的169例患者资料,男性57例,女性112例,年龄6～65(23.1±14.8)岁,儿童(<18岁)86例,成人(≥18岁)83例.结果 心律失常发生在BHUT和SNHUT阳性反应后的患者分别为75例(44.38%)、94例(55.62%).常见类型为窦性心动过缓(143例,84.62%)、交界性逸搏心律(55例,32.54%)、窦性停搏(26例,15.38%),其中窦性心动过缓在成人更多见(P<0.01),窦性停搏和交界性逸搏心律的发生无年龄、性别和试验方式差别;心律失常与晕厥或接近晕厥的临床表现几乎同时出现者为77例(45.56%)、滞后出现者92例(54.44%),并且前者多发生在BHUT中,后者多发生在SNHUT中(P<0.05);心律失常与血压下降几乎同时出现者为84例(53.50%),滞后出现者73例(46.50%),且前者多发生在BHUT中,后者多发生在SNHUT中(P<0.01).结论 (1)HUTT阳性反应发生后常见心律失常为窦性心动过缓、交界性逸搏心律和窦性停搏,窦性停搏的发生无年龄、性别和试验方式的差别,试验操作中需提高警惕;(2)BHUT中,心律失常多与晕厥或接近晕厥的表现、血压的下降同时发生;SNHUT中,心律失常多发生于晕厥或接近晕厥的表现和血压下降之后,可能与硝酸甘油药理作用有关.     

直立倾斜试验对老年不明原因晕厥患者的诊断价值

目的：探讨直立倾斜试验对老年不明原因晕厥患者的诊断价值。方法：对140例老年不明原因晕厥患者在安静环境下进行直立倾斜试验．持续监测心率和血压变化。结果：140例老年不明原因晕厥患者在直立倾斜试验中,阳性反应80例（男43例．女37例）。其中血管抑制型39例（男21例,女18例）,心脏抑制剂9例（男4例,女5例）,混合刑32例（男18例,女14例）。血管抑制型患者晕厥时与晕厥前相比,血压从（122±14／69±15）mm—Hg下降到（82±15／45±10）mmHg（P〈0．01）;心脏抑制剂患者晕厥前心率为（95±17）次／min．晕厥时下降至（51土8）次／min（P〈0．01）;混合型患者晕厥前心率为（110±21）次／min。晕厥时下降至（63±21）次／min（P〈0．01）,血压从（115±18／65±18）mmHg下降到（83±19／46±10）mmHg（P〈0．01）。结论：直立倾斜试验是诊断老年不明原因晕厥的有效方法,血管抑制型是其最常见的类型．其阳性率和血流动力学模式分布在性别上无显著性差异。     

Effects of age on outcome of tilt-table testing

Although neurally mediated syncope is thought to be common in the young and rare in the elderly, there are few data evaluating the effects of age on the outcome of tilt-table testing (TTT), especially in patients aged > or =80 years. We examined the results of TTT in 352 subjects with unexplained syncope including 133 patients >65 years of age and 43 patients >80 years of age. The average age was 54 +/- 20.8 years (range 11 to 99) and 51% were men. The TTT protocol included at least 45 minutes of upright tilt in the drug-free state with or without repeat TTT with isoproterenol or 15 minutes of upright tilt in the drug-free state followed by repeat TTT with isoproterenol. One hundred sixty-four subjects (47%) had a positive TTT. As expected, there was an age-related decline in positive TTT. A high proportion of elderly patients with unexplained syncope had a positive TTT (37% of patients aged > or =65, and 23% patients aged > or =80). Thus, TTT is a useful diagnostic test in patients aged > or =65 years with unexplained syncope.     

45例血管迷走性晕厥病人倾斜试验临床分析

目的对血管迷走神经(VS)病人的直立倾斜试验(HUT)进行临床分析.方法将45例不明原因晕厥的病人和40例健康人对照,进行基础倾斜试验(BHUT)和硝酸甘油舌下含服激发倾斜试验,观察血压、心率.结果BHUT组阳性率为13.3%,HUT加硝酸甘油含服组阳性率为51.1%,总阳性率64.4%,对照组阳性率为2.5%,晕厥组与对照组比较有统计学意义(P＜0.01).结论HUT对血管迷走神经性晕厥的诊断有较好的价值.     

The usefulness of carotid sinus massage in different patient groups

AIM: to determine the positive yield of carotid sinus massage in different patient groups: unexplained syncope, falls, dizziness and controls. DESIGN: observational study. SETTING: teaching hospital. METHODS: we studied consecutive patients over the age of 60 years referred to the 'falls clinic' with a history of unexplained syncope, unexplained falls and unexplained dizziness. We also studied asymptomatic control subjects recruited from a general practice register aged 60 years and over. All patients and control subjects underwent a full clinical assessment (comprehensive history and detailed clinical examination including supine and erect blood pressure measurements) and 12-lead electrocardiography. We performed carotid sinus massage in the supine position for 5 seconds separately on both sides followed by repeating the procedure in the upright positions using a motorised tilt table. Heart rate and blood pressure were recorded using a cardiac monitor and digital plethysmography respectively. The test was considered positive if carotid sinus massage produced asystole with more than a 3 second pause (cardioinhibitory type of carotid sinus syndrome), or a fall in systolic blood pressure of more than 50 mmHg in the absence of significant cardioinhibition (vasodepressor type of carotid sinus syndrome) or where there was evidence of both vasodepressor and cardio-inhibition as above (mixed type). RESULTS: we studied 44 asymptomatic control subjects and 221 symptomatic patients (130 with unexplained syncope, 41 with unexplained falls and 50 with unexplained dizziness). In the overall symptomatic patient group, the positive yield (any type of carotid sinus syndrome) was 17.6% (95% CI = 12.7-22.5). The positive yield in men (26.3% (95% CI = 16.4-36.2)) was twice that in women (13.1% (95% CI = 7.6-18.6)) (P = 0.014). Overall any type of carotid sinus syndrome was present in 22.3% (n = 29) of the syncope group, 17.1% (n = 7) in the unexplained fallers group and 6% (n = 3) in the dizziness group. We also found that no women with unexplained dizziness had a positive carotid sinus massage test. None of the controls demonstrated a positive response. None of the subjects suffered any complications during or after the test. CONCLUSION: the positive yield of carotid sinus massage in symptomatic patients was 17.6% with the yield in men being twice that in women. None of the asymptomatic control subjects demonstrated a positive response. The yields in unexplained syncope and unexplained falls patients were around 4-fold and 3-fold higher respectively than in unexplained dizziness patients. The positive yield in women with unexplained dizziness (without a definite history of syncope and falls) is zero. Hence, carotid sinus massage in older adults should particularly be targeted at patients with unexplained syncope and unexplained falls.     

直立倾斜试验过程中的心律失常特点及安全性评价

目的探讨直立倾斜试验（HuTT）过程中的心律失常特点及安全性。方法对165例不明原因晕厥或接近晕厥患者首先进行基础直立倾斜试验（BHUT）,阴性患者再随机进行多阶段异丙肾上腺素倾斜试验（MIHUT）或舌下含化硝酸甘油倾斜试验（SNHUT）,分析HuTT过程中心律失常发生情况。结果快速性心律失常发生率50．91％（84／165）,92．68％窦性心动过速患者出现最快心率5min内发生阳性反应。缓慢性心律失常发生率30．91％（51／165）,最常见缓慢性心律失常依次为窦性心动过缓、交界性逸搏心律和窦性停搏,其中窦性停搏10例,停搏时间MIHUT组明显高于BHUT组和SNHUT组（P均〈O．01）。结论HUTT过程中心律失常发生率较高,心率突然明显增快时应警惕阳性反应发生。试验过程中存在长时间窦性停搏等多种安全风险,SNHUT在安全性等方面优于MIHUT。