血管迷走性晕厥

血管迷走性晕厥（VVS）是临床中的最常见晕厥原因,是指各种刺激通过迷走神经介导反射导致血管扩张及心率减慢,造成脑部低灌注缺氧而出现短暂的意识丧失。VVS发作前有情绪紧张、长时站立等诱因并伴有典型的前驱症状。VVS是一种预后相对良好的疾病,在健康宣教的基础上,一般不需要特殊治疗,发作频繁、症状重者可考虑药物、起搏器或神经消融治疗。     

Management of Vasovagal Syncope

Vasovagal syncope is a common disorder of autonomic cardiovascular regulation that can be very disabling and result in a significant level of psychosocial and physical limitations. The optimal approach to treatment of patients with vasovagal syncope remains uncertain. Although many different types of treatment have been proposed and appear effective based largely on small nonrandomized studies and clinical series, there is a remarkable absence of data from large prospective clinical trials. However, based on currently available data, the pharmacologic agents most likely to be effective in the treatment of patients with vasovagal syncope include beta blockers, fludrocortisone, and alpha-adrenergic agonists. In this article, we provide a summary of the various therapeutic options that have been proposed for vasovagal syncope and review the clinical studies that form the basis of present therapy for this relatively common entity.     

Review Article: Heart Rate and Blood Pressure Control in Vasovagal Syncope

Vasovagal syncope is characterized by transient failure of usually reliable physiologic mechanisms responsible for maintaining both systemic arterial pressure and cerebral blood flow. Two circulatory phenomena are almost universally present : systemic arterial vasodilation and bradycardia. A third phenomenon, cerebrovascular constriction, has also been described but its contribution to the faint is less well established.@SU W/IND = The neural reflex pathways responsible for triggering the circulatory changes in the vasovagal faint are incompletely understood, but have recently been the subject of renewed interest. In part, this interest probably stems from the frequency with which vasovagal symptoms are now recognized to be the cause of fainting spells. Additionally, however, there is an increasingly recognized need to develop treatment strategies for those affected patients in whom recurrent vasovagal symptoms are particularly troublesome. It is the goal of this discussion to focus on those aspects of circulatory control, and in particular on potential interactions among certain neural and humoral systems, which may contribute to the inappropriate physiologic responses associated with the vasovagal faint.     

血管迷走性晕厥的诊断治疗进展

排除其他病因引起的晕厥,多数血管迷走性晕厥患者可根据其典型的临床表现获得诊断,部分患者还需进行诊断试验、如直立倾斜试验等方能得出诊断。除了安慰或有关的健康教育,大多数血管迷走性晕厥患者并不需特别治疗;但对于晕厥发作次数多、造成患者摔伤或心理压力增加的患者,还需要采取对抗压力动作、倾斜训练、药物治疗或起搏器安装等措施。现从循证医学的角度对这些诊断和治疗的方法进行了评价。     

一平苏对血管迷走性晕厥疗效观察

目的观察一平苏对血管迷走性晕厥的疗效。方法对86例倾斜试验阳性晕厥患者给予一平苏2.5mg/d,3月后复查倾斜试验并随访。结果除7例有咳嗷或其他原因退出试验外,余79例倾斜试验阴转率为75.95%。服药期间无一例发生晕厥。治疗前卧位血压为121/73mmHg,治疗后为120/76mmHg,P>0.05。心率在治疗前后分别为68±13和70±13/min,两者无显著性差异。结论一平苏可以作为治疗血管迷走性晕厥的有效药物,副作用少,对正常血压和心率无影响。     

一平苏对血管迷走性晕厥疗效观察

目的　观察一平苏对血管迷走性晕厥的疗效。方法　对 86例倾斜试验阳性晕厥患者给予一平苏 2 .5mg/d ,3月后复查倾斜试验并随访。结果　除 7例有咳嗷或其他原因退出试验外 ,余 79例倾斜试验阴转率为 75 .95 %。服药期间无一例发生晕厥。治疗前卧位血压为 12 1/73mmHg ,治疗后为 12 0 /76mmHg ,P >0 0 5。心率在治疗前后分别为 6 8± 13和 70± 13/min ,两者无显著性差异。结论　一平苏可以作为治疗血管迷走性晕厥的有效药物 ,副作用少 ,对正常血压和心率无影响。     

How and When to Pace in Vasovagal Syncope

Pacing in Vasovagal Syncope. This article discusses the indications for pacing in vasovagal syncope. It also reviews the literature on pacing results; notably, there are two small randomized controlled trials of pacing versus no therapy (or continued nondevice therapy) that show a clear benefit for pacing. The mode of benefit is, as yet, unclear. Pacing has to be dual chamber with some form of rate hysteresis. Ways of improving pacemaker therapy delivery in vasovagal syncope are anticipated.     

Pacing for Vasovagal Syncope After the Second Vasovagal Pacemaker Study (VPS II): A Matter of Judgement

Vasovagal or neurocardiogenic syncope is a common benign condition. In the majority of patients it regresses naturally, or can be controlled by conservative therapy. However there is a group of patients who remain severely affected despite lifestyle measures, counselling and medication. Pacing has been considered in these patients as a result of logic, observational studies, and three randomised but unblinded studies, VPS, VASIS and SYDIT. A randomised and blinded study, VPS II, was recently published, the results of which undermined the results of these preceding studies: despite a 30% trend towards reduced syncope in patients with active pacing, the result was not statistically significant. This left clinicians with a dilemma, whether or not to pace in patients with disabling syncope despite conservative therapy. We believe, based on a review of all currently available evidence, that there remains a role for pacing in the patient with evidence of significant cardioinhibition, particularly severe bradycardia or asystole, and ongoing disabling syncope in spite of conservative measures. When to pace in these patients is a matter of clinical judgement. The threshold for pacing should remain high, however, with extensive attempts of conservative and pharmacological measures and with appropriate discussions with patients prior to instituting pacing, regarding the risks and long-term implications of a pacemaker. More needs to be learned about optimal pacing modalities.     

Determining the Optimal Pacing Intervention Rate for Vasovagal Syncope

Introduction: In this study, patients with rate hysteresis pacemakers implanted for vasovagal syncope were re-studied using serial tilt testing to determine whether, once triggered, pacing was more effective if the intervention rate was higher than the standard rate. Methods and Results: Twenty patients (mean age 55.4 years, range 23–81, 14 male) were studied, with randomisation to either initial standard rate (80–90[emsp4 ]beats/min) intervention, or to initial high rate (120[emsp4 ]beats/min) intervention. Although 18 of the 20 reported complete abolition of syncope since pacing, only 8 patients could be objectively assessed. The respective mean time to tilt down after symptom onset with standard and high rate intervention was 193±234[emsp4 ]s and 185±143[emsp4 ]s, (P >0.05). Conclusion: Repeat tilt testing was only of limited value in assessing the benefit of pacing. There was no advantage with high rate intervention in delaying the loss of consciousness (or intolerable symptoms) after the initial onset of symptoms.     

血管迷走性晕厥的诊断治疗手段及评价

血管迷走性晕厥(VVS)的诊断主要依靠详细的病史询问和体格检查,并排除其他类型的晕厥。目前认为直立倾斜试验(HUT)是诊断VVS的“金标准”。HUT检查阴性的部分所谓不明原因晕厥的VVS病人可通过植入性心电记录仪进行诊断。偶发VVS不需要特别处理,复发性VVS及部分特殊人群才需要进一步的诊治。目前VVS尚无有效的根治方法,其治疗以预防发作为主,包括患者教育、一般治疗、药物治疗(β-受体阻滞剂、盐皮质激素、抗胆碱能药物、选择性5-羟色胺重吸收抑制剂、α-受体激动剂)及起搏器治疗等几个方面。     

血管迷走性晕厥的机理及治疗进展

血管迷走性晕厥机制复杂。Bezold-Jarisch反射是最常见的激发机制。交感神经活性变化、5-羟色胺、肾素-血管紧张素系统和内皮功能异常等在发病中起重要作用。目前血管迷走性晕厥的治疗包括一般治疗、倾斜训练、药物治疗和起搏器治疗。     

Neural Control Mechanisms and Vasovagal Syncope

Vasovagal Syncope, Patients with recurrent unexplained syncope may have cardioinhibitory and vasodepressor responses provokable with head-up tilt with or without exogenousbeta-adrenergic stimulation. Although these responses are believed to be neurally mediated, the neural mechanisms involved are pourly understood. Numerous studies have documentedperipheral vasodilation, hypotension, and bradycardia at the time of syncope and several casereports have shown sudden withdrawal of vasoconstrictor sympathetic neural outflow to skeletal muscle in human subjects. In cats and rats, a similar response can be provoked with hemorrhage and is prevented by interruption of cardiac vagal C-fiber afferents. In dogs, however, section of these fibers does not prevent the development of a vasodepressor response. Theprovocation of vasodepressor syncope during nitroprusside infusion in a heart transplantrecipient with presumed ventricular denervation also suggests that cardiac afferent nerves maynot be required for the development of vasodepressor responses in humans. Other potentialmechanisms include release of endogenous opioids or nitric oxide that may inhibit sympatheticnerve firing, and primary central nervous system activation (as in partial seizures) that triggerscardioinhibitory and vasodepressor responses. This article reviews our current understandingof the mechanisms involved in the development of neurally mediated 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.     

Syncope and Structural Heart Disease: Historical Criteria for Vasovagal Syncope and Ventricular Tachycardia

Syncope and Structural Heart Disease. Introduction: To develop evidence‐based criteria that distinguish syncope due to ventricular tachycardia (VT) from vasovagal syncope (VVS) in patients with structural heart disease (SHD). Methods and Results: One hundred and thirty‐four patients with syncope and SHD completed a 118‐item questionnaire and underwent noninvasive and invasive diagnostic assessments in a prospective cohort study. The contributions of symptoms to diagnoses were estimated with logistic regression and a point score was developed and then tested using receiver‐operator characteristic analysis. The effectiveness of the decision rule was evaluated with long‐term outcome. There were 21 patients with tilt‐positive VVS, 78 with clinically declared or inducible VT, and 35 with no identified cause of syncope. Six features were significant predictors. Factors that predicted VT included male sex and age at onset >35 years; factors predicting VVS included prolonged sitting or standing; developing presyncope preceded by stress; recurrent headaches; and experiencing fatigue, which lasts longer than 1 minute after syncope. The point score correctly classified 92% of patients, diagnosing VT with 99% sensitivity and 68% specificity. The negative predictive value is ≥96%. Fully 67% of patients with undiagnosed syncope were classified as having VT based upon their symptoms. The decision rule predicted 9‐year arrhythmia‐free survival (VVS 84%, VT 39%, hazard ratio 4.32) and 9‐year overall survival (VVS 66%, VT 37%, hazard ratio 2.87). Conclusions: The causes of syncope in patients with SHD, and their clinical outcomes, can be estimated accurately based on the clinical history. The history safely screens out the possibility of VT as a cause of syncope. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1358‐1364, December 2010)     

Predicting Recurrence of Vasovagal Syncope: A Simple Risk Score for the Clinical Routine

Background: Predictors for recurrence of syncope are lacking in patients with vasovagal syncope. The aim of this study was to identify risk factors for recurrence of syncope and develop a simple prognostic risk score of clinical value.
Methods: Two hundred seventy-six patients with a history of vasovagal syncope were prospectively followed for 2 years. Diagnosis of vasovagal syncope was based on clinical history and negative standard work-up. Inclusion in the study was independent from the result of the head-up tilt test, which was performed in all cases. Risk factors for syncope recurrence were evaluated by the Cox proportional hazards regression model and implemented in a risk score, which was validated with the log-rank test and an internal cross-validation.
Results: The Cox-regression analysis identified the number of previous syncopal events, history of bronchial asthma, and female gender as predictors for syncope recurrence (all P < 0.05). In contrast, head-up tilt test response had no predictive value (P = 0.881). Developing a risk score, study patients were identified as having high (recurrence rate during 2 years of follow-up: 37.2%), intermediate (24.8%), and low (6.5%) risk for syncope recurrence (receiver operating characteristic [ROC] of score 0.83, P < 0.01; Log-rank test for event-free survival, P < 0.005).
Conclusions: In patients with vasovagal syncope, risk of recurrence can be stratified and is predictable based on a simple risk score.     

Recent History of Vasovagal Syncope in a Young,Referral‐Based Population Is a Stronger Predictor of Recurrent Syncope Than Lifetime Syncope Burden

Syncope Prediction. Introduction: Accurate selection of patients for vasovagal syncope studies requires strong risk stratification and knowledge of the natural history of syncope. We aimed to test the hypothesis that recent history of vasovagal syncope compared to distant history better predicts subsequent recurrence of syncope. Methods and Results: In all, 208 subjects with a positive tilt test and ≥3 lifetime syncope spells were followed for 1 year. Syncope episodes in the preceding year and total historical spells were compared for their ability to predict a syncope recurrence using the criteria of optimal statistical significance, best linear separation of risk populations, and impact on power calculations. The number of vasovagal syncope spells in the preceding year better predicted syncope recurrence when compared to total number of historical spells (likelihood ratio statistic 28.4, P < 0.0001; versus 20.4, P = 0.001), and showed a substantial effect as the number of syncope events increased. For example, syncope recurred in 22% of those with <2 spells in the previous year compared to 69% in those with >6 spells. A history of no syncope compared to any syncope in the preceding year was associated with a 1‐year probability of 7% versus 46% for syncope recurrence. A study designed to detect a 50% decrease in syncope recurrence at P = 0.05 with 80% power would require 159 patients with at least 3 lifetime spells, and only 108 patients with at least 3 spells in the previous year. Conclusions: The number of syncope events in the year preceding clinical evaluation is the best predictor of syncope recurrence. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1375‐1380, December 2010)     

异丙肾上腺素后平卧位血压与血管迷走性晕厥关系的研究

目的 分析异丙肾上腺素给药后受试者平卧位心率、血压变化,探究血管迷走性晕厥（VVS）的预测指标。 方法 回顾性纳入2016年10月至2017年4月就诊于河南省人民医院内科因疑诊VVS而行二阶段法异丙肾上腺素倾斜试验（IHUTT）的患者182例。分析第一阶段阳性（阳性1组）、第二阶段阳性（阳性2组）和阴性组患者各阶段平卧位的心率、收缩压、舒张压变化,用ROC分析差异最显著的指标。 结果 IHUTT中,一阶段用药后,舒张压降幅在阳性1组和2组均显著高于阴性组[ (7.6 ± 8.4 )mmHg,（5.6 ± 7.8） mmHg,（1.9± 6.9） mmHg,P<0.001);二阶段用药后,舒张压降幅在阳性2组亦显著高于阴性组[(11.8± 9.1) mmHg比（3.3± 6.3） mmHg,P<0.001]。一阶段用药后舒张压降幅的AUC为0.639(95% CI: 0.54~0.739),ROC曲线的最佳cut-off为7.5 mmHg;二阶段用药后舒张压降幅AUC为0.778(95% CI: 0.694~0.862),ROC曲线的最佳cut-off为6.5 mmHg。 结论 平卧位静脉滴注异丙肾上腺素后受舒张压显著降低,可作为VVS的有效预测指标。