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目的应用多普勒超声显像法探讨血管迷走性晕厥(VVS)儿童的血管内皮功能。方法研究对象共20例,均为2002年1月至2003年12月在北京大学第一医院儿科就诊儿童,分为VVS组(n=10)及非VVS对照组(n=10),对10例经直立倾斜试验确诊的血管迷走性晕厥儿童,应用多普勒超声测定肱动脉的血流介导的血管舒张反应,并与10例经直立倾斜试验除外VVS的对照组儿童进行比较。结果两组患儿的年龄、性别、身高、体重、基础血压及基础肱动脉血管内径均无显著性差异,但血管迷走性晕厥儿童的血管内皮依赖性舒张功能较对照组显著增强[(11.93±4.46)%vs(8.46±2.18)%,P<0.05]。结论血管内皮依赖性舒张功能增强可能是儿童血管迷走性晕厥发生机制之一。     

儿童一过性意识丧失的基础疾病分析

目的 通过多中心、大样本的临床研究,分析儿童一过性意识丧失(transient loss of consciousness,TLOC)的基础疾病谱.方法 研究对象为1999年8月至2011年4月在北京、湖南、湖北、上海四地晕厥专科门诊就诊或住院的937例TLOC患儿,对其进行病因学分析.结果 937例TLOC患儿中,903例(96.4％)为晕厥患儿,34例(3.6％)为非晕厥患儿.903例晕厥患儿中,213例(23.6％)为血管抑制型血管迷走性晕厥(vasovagal syncope,VVS),46例(5.1％)为心脏抑制型VVS,112例(12.4％)为混合型VVS,268例(29.7％)为体位性心动过速综合征,22例(2.4％)为直立性低血压,19例(2.1％)为境遇性晕厥,21例(2.3％)为心源性晕厥,202例(22.4％)患儿为不明原因晕厥.结论 晕厥是儿童TLOC最常见的原因.在晕厥患儿中,VVS最常见,其次为体位性心动过速综合征.在VVS的3种不同血流动力学类型中,最常见的类型为血管抑制型VVS.     

心脏变时性功能在血管迷走性晕厥患儿中的临床意义

目的　研究血管迷走性晕厥（vasovagal syncope,VVS）患儿的心脏变时性功能变化及其临床意义。方法　回顾性分析2011年3月至2017年1月在北京大学第一医院儿科39例不明原因晕厥患儿的临床资料。经详细病史询问及辅助检查,28例患儿确诊为VVS,其中血管抑制型15例,混合型9例,心脏抑制型4例,11例为不明原因晕厥患儿,比较VVS患儿与不明原因晕厥患儿及不同血流动力学类型的VVS患儿之间的一般情况及运动平板试验时心率变化及心脏变时功能等情况。进一步根据VVS患儿心脏变时性功能情况分为变时性功能正常组（10例）及变时性功能不全（chronotropic incompetence,CI）组（17例,1例患儿失访）,通过随访2组患儿晕厥复发情况,观察心脏CI对VVS患儿预后的影响。结果　VVS患儿与不明原因晕厥患儿相比较,人口学指标均无显著性差异,在运动平板试验中VVS患儿运动时最快心率及心脏变时性指数显著低于不明原因晕厥患儿（P＜0.05）,VVS患儿的CI发生率显著高于不明原因晕厥患儿（64.3% vs. 27.3%,P＜0.05）。不同血流动力学类型的VVS患儿比较,心脏抑制型及混合型患儿CI的发生率显著高于血管抑制型患儿。通过对27例VVS患儿随访发现,伴有CI的VVS患儿晕厥的复发率显著高于不伴有CI的患儿（P＜0.05）,以患儿晕厥复发的时间作为随访终点对VVS患儿进行生存分析,有CI的VVS患儿较无CI的患儿对治疗的反应不佳（Log-rank：P＝0.028）。结论　心脏变时性功能在VVS患儿中有显著的改变,尤其常见于心脏抑制型和混合型患儿。伴有CI的VVS患儿对治疗的反应不佳。     

不同血流动力学类型血管迷走性晕厥63例预后研究

探讨不同血流动力学类型血管迷走性晕厥 （vasovagal syncope,VVS）患儿的个体化治疗方案。方法　对2004年4月至2010年6月在北京大学第一医院就诊的63例VVS患儿进行门诊或电话随访。年龄6～19岁,平均（11.57±2.89）岁。其中血管抑制型32例、混合型、心脏抑制型31例,服用口服补液盐者14例、美托洛尔13例、盐酸米多君36例。随访时间3～48个月,平均（21±12）个月。分析采用不同治疗的不同血流动学类型VVS患儿3个月内复发情况,评价短期疗效;以复发为终点事件,作Kaplan-Meier曲线,比较VVS患儿应用不同治疗的长期疗效。结果　以上3种治疗药物对不同血流动力学类型VVS患儿的短期疗效差异无统计学意义（P均 > 0.05）。不同血流动力学类型VVS患儿接受口服补液盐或美托洛尔治疗后,长期疗效差异均无统计学意义（P > 0.05）,盐酸米多君对混合型及心脏抑制型VVS的疗效优于血管抑制型（P < 0.01）。结论　口服补液盐、美托洛尔或盐酸米多君均适于VVS患儿的治疗,与VVS血管抑制型患儿相比,盐酸米多君对混合型及心脏抑制型患儿的长期疗效更佳。     

儿童血管迷走性晕厥的临床特征及血浆和血小板中5-羟色胺的变化

目的 探讨小儿血管迷走性晕厥的临床特征和血浆、血小板中5-羟色胺(5-HT)的变化.方法 2006年10月-2009年2月在首都儿科研究所经直立倾斜试验(head-up tilt test,HUTT)确诊为血管迷走性晕厥(VVS)患儿41例(HUTT阳性组),诊断标准参照基础HUTT对儿童不明原因晕厥的诊断研究,男17名,女24名,年龄6～14岁,平均年龄(10.5 ±1.8)岁.匹配健康儿童(对照组):当地幼儿园和中小学36名健康小儿,男16名,女20名,年龄9～14岁,平均年龄(10.7±1.5)岁.分析晕厥诱因和先兆症状、HUTT反应方式、晕厥发作时间、VVS患儿静息状态各亚型血压和心率变化等临床特点.全体研究对象抽取静脉血3 ml,用双抗体夹心酶标免疫分析(ELISA)法对41例血管迷走性晕厥患儿及36名健康儿童的血浆和血小板中5-HT进行测定.结果 ①41例血管迷走性患儿平均年龄为(10.5±1.8)岁,女童比例高于男童,为1.4:1.②VVS先兆症状:患儿中33例存在晕厥先兆(80.4%),其中头晕发生率高达78.8%.③VVS发生诱因:儿童VVS发作前常存在诱发因素,包括:长久站立、劳累、情绪影响等.其中长久站立比例最高,达90.2%.④HUTT平均反应时间及晕厥持续时间:基础直立倾斜试验(BHUT)阶段平均反应时间为(20.6±8.6)min;舌下含化硝酸甘油激发倾斜试验(SNHUT)阶段平均反应时间(5.0±2.2)min.晕厥持续时间均短于5 min.⑤HUTT不间反应类型的分布:血管抑制型61.0%,混合型24.4%,心脏抑制型14.6%.⑥血压和心率的比较:VVS患儿和正常儿童静息状态下基础心率、收缩压、舒张压相比差异无统计学意义;VVS患儿中血管抑制型、混合型和心脏抑制型静息状态下基础心率、收缩压、舒张压相比差异无统计学意义.⑦VVS患儿基础状态和HUTT阳性时血浆中5-HT较对照组差异无统计学意义[(27.51±1.32)μg/Lvs.(27.28±2.48)μg/L,t=0.518,P=0.606;(27.51±1.32)μg/L vs.(28.05 ±1.40)μg/L,t=2.044,P=0.167],基础状态下血小板5-HT与对照组之间差异无统计学意义[(82.30 ±6.06)10~9ng/L vs.(79.88±5.79)10~9ng/L,t=1.788,P=0.780].⑧VVS患儿基础状态下和HUTT阳性时的血小板5-HT比较差异有统计学意义[(82.30±6.06)10~9ns/L vs.(97.90±6.59)10~9ng/L,t=11.26,P=0.00].结论 VVS患儿具有明显的临床特征;VVS患儿基础状态和晕厥(或晕厥先兆发生时)血浆中5-HT变化不明显;VVS患儿晕厥或晕厥先兆发生时血小板5-HT明显升高,提示中枢5-HT系统可能参与了VVS的发病过程.     

经颅多普勒超声检测血管迷走性晕厥患儿脑血流动力学变化分析

目的 采用经颅多普勒超声（TCD）分析血管迷走性晕厥（VVS）的脑血流动力学特点,并探讨TCD对VVS的临床应用价值。方法 对2011年12月至2013年8月于兰州大学第二医院小儿心血管科就诊的38例血管迷走性晕厥患儿,及20名体检健康儿童行直立倾斜试验,并应用TCD进行监测。结果 基础状态下,观察组与对照组比较,左右大脑中动脉的收缩期血流速度（Vs）、舒张末期血流速度（Vd）、平均血流速度（Vm）差异无统计学意义（P＞0.05）,脉冲指数（PI）值差异无统计学意义（P＞0.05）;对照组行直立倾斜试验后与基础状态时比较,左右大脑中动脉的Vs、Vd、Vm差异无统计学意义（P＞0.05）,PI值差异无统计学意义（P＞0.05）;观察组通过直立倾斜试验诱发血管迷走性晕厥阳性反应时与基础状态时比较,左右大脑中动脉的Vs、Vd、Vm明显加快（P＜0.05）,PI值明显升高（P＜0.05）。结论 VVS发生时,脑血管阻力增加,脑血流调节障碍;TCD检查对于判断VVS患儿脑血流状态具有重要价值。     

血管迷走性晕厥儿童心率变异性分析

目的探讨血管迷走性晕厥(VVS)儿童的心率变异性(HRV)。方法对27例不明原因晕厥患儿经直立倾斜试验(HUTT)检查阳性并诊断为VVS的HRV进行分析(研究组),并将29例健康儿童作为对照(对照组)。采用康泰TLC3000A12通道动态心电图分析系统描记未发生晕厥时24h心电图,分析时域指标和频域指标,应用SPSS11.0软件进行统计学处理。结果研究组低频功率(LF)与对照组比较明显降低(P<0.05);频域指标与时域指标在不同年龄段差别不明显(P>0.05);女性时域指标中SDANN及VLF、LF较男性明显降低(P<0.05);血管抑制型与混合型VVS的HRV指标差异不明显。结论VVS儿童基础自主神经功能发生改变;HRV主要受性别影响,而年龄影响不明显;HUTT不同反应类型VVS的HRV不存在差别。     

患儿血管迷走性晕厥直立倾斜试验血浆C型钠尿肽变化及其意义

目的探讨血管迷走性晕厥(vasovagal syncope,VVS)患儿血浆C-型钠尿肽(c-type natriuretic peptide,CNP)含量的变化。方法研究对象包括31例VVS患儿,均为2013年12月至2014年6月在北京大学第一医院儿科以直立不耐受症状入院的患儿,均经过详细病史询问、体格检查及相关实验室检查以及直立倾斜试验(HUTT)确诊为VVS,平均年龄为(11±3)岁;32名健康儿童为对照组,均为经过详细病史及体格检查等确定为健康的儿童,平均年龄为(11±2)岁。心率、血压的监测采用无创连续血压监测仪连续监测。血浆CNP的测定采用夹心免疫发光法。结果 VVS组与对照组的性别比、年龄、身高、体重、平卧位血压及心率差异均无统计学意义(P0.05);VVS患儿血浆中CNP含量明显高于正常儿童[(35.7±21.5)ng/L vs.(23.2±8.0)ng/L,P0.01)];VVS患儿的晕厥频率与血浆中的CNP含量呈明显正相关(n=31,r=0.85,P0.01)。VVS组平卧状态下及HUTT中阳性反应时的血浆CNP含量差异无统计学意义[(36.3±21.0)ng/L vs.(42±57)ng/L,P0.05]。结论 VVS患儿血浆CNP含量高于对照组,且血浆CNP含量与患儿晕厥频率相关,可能参与了VVS的发病过程。     

肾素-血管紧张素-醛固酮系统与血管迷走性晕厥的关系

血管迷走性晕厥(VVS)是指由多种因素触发神经反射引起周围血管扩张、低血压、心动过缓及一过性脑缺血所致的自限性晕厥发作.肾素-血管紧张素一醛固酮系统是人体内重要的神经内分泌系统,其活性与血流动力学改变及交感神经活性密切相关.在VVS发作前后,血浆肾素、血管紧张素和醛固酮水平发生变化,提示肾素-血管紧张素-醛固酮系统与VVS存在一定关系.     

儿童恶性血管迷走性晕厥危险因素分析

目的分析儿童恶性血管迷走性晕厥(VVS)的临床特点及其危险因素。方法病例对照研究。收集2017年6月至2021年12月在首都儿科研究所附属儿童医院心内科住院治疗并诊断VVS的368例患儿的病例资料。根据在晕厥过程中是否发生3 s以上窦性停搏分为恶性VVS组与非恶性VVS组, 比较两组患儿的人口学特征。以病例信息完整的恶性VVS作为病例组, 按照年龄、性别1∶4比例匹配同期非恶性VVS组的患儿作为对照组, 分析比较两组患儿的临床特征及相关检查指标。组间比较采用独立样本t检验、Mann-WhitneyU或χ2检验。采用Logistic回归分析恶性VVS的危险因素。结果符合标准的恶性VVS患儿11例, 非恶性VVS患儿342例。病例组11例, 对照组44例, 11例病例组中10例心脏停搏发生在直立倾斜试验倾斜过程的第35(28, 35)分钟, 窦性停搏时长(9±5)s;1例晕厥发生在患儿排队等待采血过程中, 窦性停搏时长为3.4 s。恶性VVS组年龄小于非恶性VVS组, 差异有统计学意义[9(7, 10)比 12(10, 14)岁, P<0.05]。病例组患儿平均血红蛋白浓度(MCHC...     

Physiologic neurocirculatory patterns in the head-up tilt test in children with orthostatic intolerance

Background: Orthostatic intolerance (OI) is a common clinical manifestation in clinical pediatrics. The head‐up tilt (HUT) table test is considered the standard of orthostatic assessment, but the physiologic neurocirculatory profile during HUT has not been fully realized in children with OI. The present study, therefore, was designed to investigate the physiologic patterns that occur during HUT in children with OI. Methods: Ninety children (56 girls; mean age, 11.6 ± 2.3 years) with OI underwent HUT under quiet circumstances. Blood pressure and heart rate were monitored simultaneously. Results: Forty‐nine children with OI (54.4%) had vasovagal response with HUT testing; 33 (36.7%), vasodepressor response; six (6.7%), cardioinhibitory response; and 10 (11.1%), mixed response. Twenty‐eight children (31.1%) had postural orthostatic tachycardia; one (1.1%), orthostatic hypotension (OH); and 12 (13.3%), normal physiologic response. Patterns of cerebral syncope response and chronotropic incompetence were not observed. Conclusions: Classical vasovagal response was the major physiologic pattern seen in children with OI during HUT testing, and postural orthostatic tachycardia response ranked second.     

The value of the head-up tilt table test for with unexplained syncope in children and young adolescents

Syncope occurs in about 15% of children and young adolescents. The diagnosis of syncope of unknown origin is frequently difficult. In 1986, Kenny et al. introduced the Head-up Tilt Table Test (HUT), which enables to reproduce syncope. The aim of the study was to evaluate HUT in diagnosis of syncope in children and young adolescents. Ninety five children and young adolescents (57 females, 38 males, age range 7-18 years) with recurrent syncope of unexplained etiology were referred for HUT. The study group was divided into two subgroups: A--with history consistent with vasovagal syncope (VVS) and B--with non-characteristic symptoms for VVS. HUT was performed according to the Westminster protocol. The patient was tilted at 60 degree for 45 min. or until syncope occurred. Positive response to HUT was 36%. Negative outcome occurred in 59%. Non-diagnostic HUT was observed in 5%. The vasodepressive type of VVS was recognised in 35%, cardioinhibitory in 12% and mixed in 53%. In group A positive response of HUT occurred in 65% of pts., negative in 31%. In group B positive HUT was observed in 4% of pts. and negative in 89%. CONCLUSIONS: 1. In children and young adolescents head-up tilt test is a very useful diagnostic method. 2. In patients referred for the head-up tilt test the history of syncope should be taken into consideration.     

一氧化氮和内皮型一氧化氮合成酶与血管迷走性晕厥发病的关系

目的：探讨一氧化氮和内皮型一氧化氮合成酶与儿童血管迷走性晕厥发病的关系。方法：血管迷走性晕厥患儿14例（A组）,其他原因引起晕厥患儿10例（B组）,健康志愿者20例（C组）。于倾斜试验（HUT）前和倾斜不同时间测定A组与B组患儿的血浆一氧化氮（NO）水平,同时对3组儿童进行内皮型一氧化氮合成酶（eNOS）基因G894T多态性检测。结果：①A组患儿出现阳性反应时血浆NO水平较平卧时显著升高（76.7±9.6 vs 90.0±11.4 μmol/L, P<0.05）;②A组患儿在症状好转后血浆NO水平较试验前显著降低（82.7±9.2 vs 61.5±6.9 μmol/L,P<0.01）;③B组患儿倾斜时血浆NO水平较平卧时差异无显著性;④A,B两组患儿的血压、心率变化与NO水平无显著相关性;⑤A组患儿eNOS基因G894T突变型基因频率显著高于B组与C组(42.9% vs 10%, P<0.05)。结论： 倾斜体位时血浆NO水平异常升高可能参与了血浆血管迷走性晕厥的发病机制,而其升高水平可能与eNOS基因G894T多态性表达有关。     

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??Objective??To evaluate the chronotropic competence in children with vasovagal syncope ??VVS??. Methods??Thirty-nine patients??17 males??22 females??age ranging from 8-16 years?? with syncope were included in the study??and 28 were diagnosed with VVS??including 15 cases of vasodepressor type??9 cases of mixed type??and 4 cases of cardioinhibitory type??11 were with unexplained cause of syncope. A treadmill test was performed and heart-rate response during exercise was evaluated by the chronotropic reserve. Demographic data and change of heart rate??blood pressure during test and CRI were compared between the 2 groups and different types of VVS. Furthermore??based on CRI??patients with VVS were divided into the normal chrontropic group??n??10?? and CI group??n??17??. By following the recurrence of syncope of 2 groups??the effect of CI on the prognosis of VVS in children was observed. Results??There were no significant differences between children with VVS and with unexplained syncope in sex??age??BMI??baseline heart rate??MaxMET or baseline blood pressure. But during exercise test??peak heart rate and CRI were significantly lower in children with VVS than in unexplained syncope. The incidence of CI in children with VVS was significantly higher than that in children with unexplained syncope??64.3% vs. 27.3%??P??0.05??. The incidence of CI in VVS with vasodepressor-type in children was significantly lower than those with cardioinhibitory-type and mixed-type. During following-up period??the recurrence rate of syncope in VVS children with CI was significantly higher than that of children without CI. Patients with CI had significantly worse prognosis compared to those without CI??Log-rank??P??0.028??. Conclusion??Chrontropic competence is significantly altered in children with VVS??especially in cardioinhibitory-type and mixed-type in children. CI is the significant predictor for poor prognosis in children with VVS.     

β受体阻滞剂治疗儿童自主神经介导性晕厥的多中心研究

目的 探讨β受体阻滞剂对自主神经介导性晕厥儿童的治疗效果.方法 研究对象为1995年5月至2006年4月在北京、湖南、湖北、上海4地就诊或住院的103例自主神经介导性晕厥或接近晕厥患儿,其中男43例,女60例;年龄5～19岁,平均(12.0±2.6)岁.其中血管迷走性晕厥(VVS)患儿49例,体位性心动过速综合征(POTS)患儿54例.分别将VVS以及POTS患儿随机分为治疗组(口服美托洛尔治疗)和对照组(口服补液盐治疗),观察2组儿童临床晕厥发作次数及直立倾斜试验结果,采用SPSS 10.0软件进行统计学分析.结果 VVS和POTS治疗组的治愈率分别为60.61%和68.75%,对照组分别为18.75%和0.00%.两治疗组好转率分别为15.15%和15.63%,对照组为6.25%和40.91%.治疗组HUT转阴率分别为60.61%和68.75%,对照组为18.75%和9.09%.两治疗组的有效率、治愈率和HUT转阴率均明显高于对照组(P均＜0.01).结论 β受体阻滞剂对VVS患儿以及POTS患儿的治疗有效.     

GNB3C825T基因多态性与儿童血管迷走性晕厥相关性的初步探讨

目的 初步探讨GNB3C825T基因多态性与小儿血管迷走性晕厥(vasovagal syncope,VVS)的相关性.方法 晕厥组为不明原因晕厥患儿54例,其中男18例,女36例,平均11.8岁;对照组为同期健康体检儿童54名,其中男20名,女34名,平均11.2岁;入选病例均行直立倾斜试验(head-up tilt test,HUTT),根据HUTT试验结果 ,分HUTT阳性组即VVS组和HUTT阴性组,各组病例均抽取外周血,应用聚合酶链反应(polymerase chain reaction,PCR)和基因测序的方法 检测GNB3C825T基因多态性.结果 晕厥组54例患儿,HUTT阳性者30例,其中血管抑制型15例(50.0%)、混合型9例(30.0%)和心脏抑制型6例(20.0%),对照组皆为阴性;GNB3C825T等位基因T在对照组的频率低于晕厥组(18.5%vs 34.3%),两组比较差异有统计学意义(x2=6.888,P＜0.05);GNB3C825T等位基因T在VVS组的频率高于HUTT阴性组(38.3%vs 18.7%),两组比较差异有统计学意义(x2=4.905,P＜0.05);VVS组各临床分型间的等位基因频率的比较差异无统计学意义(x2=0.658,P＞0.05).结论 GNB3C825T等位基因频率与VVS有相关性,可考虑作为小儿VVS的候选易感基因,提供临床早期筛查.     

The efficacy of midodrine hydrochloride in the treatment of children with vasovagal syncope

OBJECTIVE: To determine whether midodrine hydrochloride therapy can prevent vasovagal syncope (VVS) in pediatric patients. STUDY DESIGN: Children with recurrent syncope (n = 26) were randomly assigned into 2 groups. Group I comprised children given midodrine hydrochloride as first-line therapy in addition to conventional therapy, and group II comprised patients receiving conventional therapy only. Repeat head-up tilt (HUT) testing and follow-up of least 6 months were conducted to evaluate the therapeutic effectiveness and side effects of midodrine in treating VVS in children. RESULTS: The HUT-based effective rate was significantly higher in group I than in group II (75% vs 20%; P < .05). During the follow-up period, the recurrence of syncope was significantly lower in group I than in group II (P < .05). CONCLUSIONS: Midodrine hydrochlorate is effective in treating VVS in children, especially in preventing recurrent episodes. Few side effects were observed in the present study.