直立抬头倾斜试验诊断不明原因晕厥

作者对10例反复发作而原因未明的晕厥患者进行了基本倾斜试验或多阶段异丙基肾上腺素倾斜试验,10例中男4、女6,平均年龄41.2岁,平均病程53.1月。6例在试验中诱发了晕厥或晕厥先兆症状,伴有血压下降及心动徐缓而确诊为血管迷走神经性晕厥,我们认为直立抬头倾斜试验对血管迷走神经性晕厥的诊断是一种有价值的检测方法。     

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。     

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.     

13家医疗机构儿科常用中成药说明书信息及标注情况分析

目的：探讨儿童血管迷走性晕厥的合理治疗方法。方法：采用回顾性研究方法,选取我院2017年3月至2018年6月收治的血管迷走性晕厥患儿65例,按照不同治疗方案分为健康教育组20例、基础治疗组（健康教育结合增加盐水摄入和直立训练）22例和药物治疗组（基础治疗+美托洛尔）23例,比较三组患儿的主观疗效、客观疗效（直立倾斜试验）。结果：健康教育组、基础治疗组和药物治疗组的主观疗效好转率分别为35.0%（7/20）、68.2%（15/22）和65.2%（15/23）,基础治疗组和药物治疗组的主观疗效好转率比较差异无统计学意义（2=0.04,P>0.05）,但均高于健康教育组（2分别为4.62和3.90,P均<0.05）。三组的客观疗效好转率分别为25.0%（5/20）、68.2%（15/22）和95.7%（22/23）,药物治疗组高于基础治疗组和健康教育组（2分别为4.07和7.83,P均<0.05）。三组患儿均未发生明显不良反应。结论：儿童血管迷走性晕厥的治疗应首选健康教育结合增加盐水摄入和自主神经功能锻炼,对于反复发作次数较多以及非药物治疗疗效欠佳者需考虑药物治疗。     

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。     

自主神经在倾斜试验诱发血管迷走性晕厥中的作用

应用心率功率谱分析技术，评价倾斜试验诱发血管迷走性晕厥中自主神经的作用。结果显示，基础倾斜前基础阳性组高频（HF）成分明显低于静滴导两基肾上腺素倾斜试验阳性组（ISO阳性组）和对照组，低频（LF）／HF比值显著高于对照组。阳性反应前两个阳性组LF成分均较基础倾斜前显著增强（P＜0．05和＜0．01），HF成分则显著减弱（P均＜0．01），LF／HF比值亦显著增大（P均＜0．01）。表明自主神经功能调节障碍在倾斜试验诱发血管迷走性晕厥的发生机制中起着重要作用。     

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。     

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.     

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。     

Drug Treatment of Orthostatic Hypotension Because of Autonomic Failure or Neurocardiogenic Syncope

Orthostatic hypotension either because of autonomic failure or neurocardiogenic syncope can be very incapacitating and should be treated accordingly. Drug therapy is frequently needed to alleviate orthostatic symptoms. The physiopathological basis of neurocardiogenic syncope and of autonomic failure is completely different and their treatment should be distinct. In the past 5 years, many randomized, placebo-controlled trials have shed light on the efficacy of specific pressor drugs. In patients with orthostatic hypotension because of autonomic failure, α-adrenoceptor agonists, and midodrine in particular, have been shown to increase standing blood pressure and decrease orthostatic symptoms. Other drugs such as octreotide, indomethacin or ergotamine have also been shown to elevate standing blood pressure and/or orthostatic tolerance. Fludrocortisone is a well known and frequently used pressor drug but randomized controlled studies are needed to measure its efficacy. In patients with orthostatic hypotension associated with neurocardiogenic syncope, clinical trials have demonstrated that β-blockers, especially β₁-selective agents without intrinsic sympathomimetic activity such as atenolol, midodrine and paroxetine can decrease recurrence of syncope. Treatment algorithms, such as those presented in this review, should always be interpreted in the light of individual patient characteristics. Many of the drugs used for orthostatic hypotension have multiple indications and contraindications that should influence therapeutic decisions. Little is known about the effectiveness and tolerability of specific combinations of pressor drugs. Consequently, sound clinical judgment and close follow-up of patients should always guide combination therapy.     

Treatment questions in POTS with hypertension and syncope

A 27-year old man experienced recurrent syncope with prodromal palpitations and resultant injury. The features of these episodes suggested a potentially neurally-mediated mechanism. Head-up tilt test revealed the postural orthostatic tachycardia syndrome (POTS). Within the first minutes of upright posture during the total head-up tilt testing, a heart rate increase of >30 beats/min and to a maximum of 150 beats/min was documented in the patient. At the end of passive tilting, the patient lost consciousness in the absence of hypotension while in sinus rhythm of 140 bpm. The 12-lead ECG and electrophysiological study showed no abnormalities. The patient received a beta-adrenergic blocker, a selective central imidazoline receptor agonist and psychiatric therapy, resulting in only a short-term improvement.     

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.     

Neurocardiogenic syncope: latest pharmacological therapies

Neurocardiogenic syncope is a neurally mediated disorder and is a common cause of syncope. The goal of treatment is to prevent recurrences with the aim of improving quality of life and reducing morbidity. Reassurance, in some cases, may suffice. In others, augmenting central blood volume by increasing fluid and/or salt intake is effective. The role of non-pharmacological physical manoeuvres is increasingly recognised, given the increasing clinical trial data supporting their efficacy. This review summarises the clinical evidence for a variety of pharmacological agents. Of these, midodrine appears to have yielded the most consistent favourable outcome. Its use, however, should be reserved for patients with recurrent and refractory syncope.     

Transcardiac gradient of aldosterone before and after spironolactone in patients with congestive heart failure

Isoproterenol is widely used as a provocative medium for vasovagal responses during tilt testing. Dose of isoproterenol infusion is generally titrated empirically by increase in resting heart rate before tilt up. To determine the optimal increase in resting heart rate with isoproterenol for tilt-induced vasovagal responses, we studied 97 consecutive patients with unexplained syncope. After the end of a negative baseline tilt (80 degrees for 30 min), the isoproterenol tilt was performed using one of two protocols: two-stage isoproterenol-tilt protocol, with doses of 0.01 and 0.02 microg/kg per min for 10 min each, or one-stage isoproterenol-tilt protocol, with a dose of 1 or 2 microg/min for 10 min. The resting heart rate increase was defined as a percentage increase in the resting heart rate after isoproterenol infusion, compared to the baseline heart rate before the tilt test. In 117 tilt procedures, 28 (93%) of the 30 positive responses occurred with a resting heart rate increase of > or = 21%. With the resting heart rate increase of 60 and 100%, 18 (60%) and 27 (90%) positive responses were observed, respectively. In conclusion, the minimum resting heart rate increase of > or = 21% was required to provoke a vasovagal response during subsequent isoproterenol-tilt (80 degrees for 10 min). Preferably, heart rate should be increased to 60-100% by isoproterenol titration before tilting.     

Vasovagal syncope: an update on the latest pharmacological therapies

Introduction: Syncope is an abrupt loss of consciousness in response to reduced perfusion to the brain. Neurocardiogenic or vasovagal syncope results from a complex neurologic reflex, and treatments to prevent recurrence attempt to modulate aspects of that reflex.

Areas covered: Pharmacologic treatments for vasovagal syncope address the syncope reflex in multiple ways. Fludrocortisone and sodium chloride increase systemic fluid volume. Midodrine, β blockers and norepinephrine transport inhibitors modulate the sympathetic nervous system. Other treatments for syncope modulate other neurotransmitters or affect heart rate. The most recent trials evaluating established and novel therapies are reviewed.

Expert opinion: To reduce recurrence of vasovagal syncope, conservative measures are first line. If these fail to prevent recurrence, the most promising medical therapy includes midodrine. Randomized placebo-controlled data evaluating fludrocortisone, midodrine and β blockers in older patients are awaited. Because of the significance of the placebo effect in this condition, any treatment must be evaluated in a randomized double-blind placebo-controlled trial before being accepted as effective.     

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.     

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％。     

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.     

儿童血管迷走性晕厥在直立倾斜试验中的特点

目的探讨儿童血管迷走性晕厥(vasovagal syncope,VVS)在直立倾斜试验(head-up tilt test,HUTT)中的特点,寻找VVS在HUTT中发生晕厥的预警指标,以便早期识别VVS阳性反应,降低检查风险。方法回顾性分析2018年1月~2019年8月因不明原因晕厥于某院行HUTT检查的患儿在HUTT中临床表现、心率及心电图等特点。结果①基础直立倾斜试验(based head-up tilt test,BHUT)中,临床表现胸闷在阴性组有1例(2%),VVS组9例(22%),差异具有统计学意义(P<0.05)。②硝酸甘油激发直立倾斜试验(sublingual nitroglycerin head-up tilt test,SNHUT)中,临床表现头晕、胸闷、面色苍白、恶心、视物模糊、乏力及发热在两组有统计学差异(P<0.05)。③HUTT中心电图,阴性组和VVS组有统计学差异(P<0.05)。④VVS阳性反应平均时间是在SNHUT开始后的5~10 min,且在SNHUT开始后的前3 min心率较试验前基础心率平均上升30.4%。结论通过观察HUTT中临床表现、心率变化及心电图改变,可一定程度上预测VVS的发生。     

Heart rate control in hypertensive patients treated by captopril

1 The effect of captopril on autonomic reflex functions has been investigated in fifteen patients with essential hypertension by examining their responses to tests of baroreceptor function (Valsalva's manoeuvre and upright posture), sympathetic nervous system reactivity (cold pressor and mental stress tests) and parasympathetic reactivity (diving test) before and after 3 weeks' treatment with captopril. 2 Captopril significantly reduced arterial blood pressure and resting heart rate but did not affect cardiovascular responses to Valsalva's manoeuvre, upright posture, cold pressor and mental stress tests. 3 The bradycardia associated with the diving reflex test was significantly enhanced by captopril (P less than 0.01). 4 These results indicate that treatment with captopril is associated with increased parasympathetic tone but without inhibition of baroreceptor or sympathetic reflexes.