王成医生的科普号

1.健康教育：做好心理调适与行为调整，避免单独活动。正确识别晕厥先兆,保持活动场所空气流通，晕厥发作时采取平卧体位，或取坐位、蹲位、双腿交叉等姿势。生活中避免脱水、持久站立、体位突然改变、环境闷热。2.锻炼与衣着：坚持规律站立锻炼,靠墙站立每次30分钟,每日2次。穿紧身裤、或连裤袜、或用腹带。3.饮食增加水盐摄入：每日饮水800毫升以上，上午和下午各2次尿，保持尿色清亮。食物含盐量相对增加（除外直立性高血压）。少吃零食。4.睡眠时间：每日不少于8小时睡眠。5.口服补液盐I（除外直立性高血压）：14.75克/袋，每日1袋，溶于500毫升水，分次口服。或口服补液盐III（除外直立性高血压）：5.125克/袋，每日2袋，每袋溶于250毫升水，分次口服。6.疗程：连续治疗2～3个月，不宜随意中断治疗。初次治疗2～3周后复诊。本文系王成医生授权好大夫在线（www.haodf.com）发布，未经授权请勿转载。

心电图 Ｐ 波是心房去极波，Ｐ 波与诸多疾病相关可作为其诊断标准、预后指标，具有较重要的临床价值。 自主神经介导性晕厥(ＮＭＳ)是以由自主神经介导的反射调节异常或自主神经功能障碍为主要因素所导致的晕厥，同时ＮＭＳ 也是儿童和青少年最常见的晕厥类型。研究表明，心电图 Ｐ 波能提供大量与 ＮＭＳ 相关的信息，在 ＮＭＳ 的患者中，Ｐ 波时间(Ｐｗｄ)、Ｐ 波离散度(Ｐｄ)、Ｐ 波电压均存在临床意义。 因此，心电图 Ｐ 波可能成为儿童青少年 ＮＭＳ 预后的重要心电学指标。 该文对心电图 Ｐ 波与儿童青少年自主神经介导性晕厥预后的关系进行综述。

儿童心脏性猝死少见但危害性极大，儿童心脏性猝死多发生在院外突发性强抢救成功率低，对家庭和社会均造成严重后果 与儿童其他致命事件相比(如车祸、溺水等)，儿童心脏性猝死更受关注。儿童心脏性猝死一直被视为临床心脏病学、急诊医学和公共卫生领域面临的重大问题，降低儿童心脏性猝死发生率关键是早期发现、早期预防。 随着检查技术领域的不断进展，对心电图 Ｔ 波的认识越来越深入，Ｔ 波已成为预测儿童心脏性猝死的重要指标 该文将综述 Ｔ 波及儿童心脏性猝死研究进展

[摘要] 目的 探讨直立倾斜试验（HUTT）不同时间点心率（HR）和心率差（HRD）与儿童及青少年体位性心动过速综合征（POTS）发生的关系。方法 收集2000年10月至2019年11月因不明原因晕厥或晕厥先兆在中南大学湘雅二医院儿童晕厥专科门诊就诊、并诊断为POTS的6～16岁儿童及青少年217例（POTS组）。匹配同期在本院儿童保健专科门诊进行健康检查的6～16岁儿童及青少年73例为对照（对照组）。获取基线、HUTT 5 min、10 min的HR（HR0、HR5、HR10）及HUTT 5 min、10min时HR与基线HR的差值即HRD（HRD5、HRD10）。结果 （1）HR5、HR10、HRD5、HRD10在POTS组高于对照组（P<0.05）。（2）单变量logistic回归：HR5、HR10、HRD5、HRD10与发生POTS的风险之间存在关联（P<0.01）。（3）多变量logistic回归：HRD5、HRD10分别每增加一个单位，发生POTS的风险分别增加27%（OR=1.27，95%CI 1.16～1.36）和28%（OR=1.28，95%CI 1.20～1.38），这是在分别调整了年龄、性别、HR10或HR5后的独立作用。结论 HR和HRD与儿童及青少年POTS发生存在关联，但HUTT不同时间点的HR和HRD对发生POTS的效应值大小影响不大。

目的 探讨不同体质量指数(BMI)血管迷走性晕厥心脏抑制型（VVS-CI）儿童心率变异性（HRV）的差异。方法 回顾性分析2012年1月至2019年12月因晕厥或晕厥先兆在中南大学湘雅二医院儿童晕厥专科门诊诊断为VVS-CI的34例儿童临床资料。根据身长、体质量计算体质量指数（BMI），分为偏瘦组（BMI≤18.4 kg/m2，n=19）和正常组（BMI 18.5～23.9kg/m2，n=15）。对24h动态心电图HRV进行分析。HRV分析采用线性分析法，时域指标SDNN、SDANN、rMSSD和pNN50，频域指标TP、ULF、VLF、LF、HF和LF/HF。采用SPSS 22.0进行统计学处理。结果 偏瘦组与正常组比较SDNN、SDANN和rMSSD无统计学差异（P＞0.05），pNN50升高（P＜0.05）。两组间TP、ULF、LF、HF和LF/HF无统计学差异（P＞0.05），偏瘦组较正常组VLF降低（P＜0.05）。偏瘦组、正常组不同性别之间时域指标、频域指标无统计学差异（P＞0.05）。偏瘦组＜12岁较≥12岁SDNN、SDANN、LF升高（P＜0.05），rMSSD、pNN50、TP、ULF、VLF、HF和LF/HF无统计学差异（P＞0.05）。正常组＜12岁较≥12岁ULF升高、LF降低（P＜0.05），SDNN、SDANN、rMSSD、pNN50、TP、VLF、HF和LF/HF无统计学差异（P＞0.05）。结论 低BMI与正常BMI的VVS-CI儿童自主神经调节功能不同，引起HRV存在差异。相同BMI＜12岁与≥12岁儿童之间HRV也存在差异。

目的 探讨QT间期离散度（QT interval dispersion,QTd）对儿童及青少年心脏抑制型血管迷走性晕厥（Cardioinhibitory vasovagalsyncope,VVS-CI）的诊断效能及预后估测价值。方法 选择2010年7月至2020年1月因晕厥或晕厥先兆在中南大学湘雅二医院儿童晕厥专科门诊首次就诊或住院、明确诊断为VVS-CI的儿童及青少年80例为VVS-CI组，匹配同期在本院进行健康体检的儿童及青少年80例为对照组。测量两组基础状态下12导联心电图QT间期，SPSS 19.0统计软件进行数据处理。结果 （1）两组比较：VVS-CI组较对照组心率降低（P<0.05），最大QT间期（Maximum QT interval, QTmax）、最小QT间期（Minimum QT interval,QTmin）、QT间期离散度（QTd）、校正最大QT间期（Corrected maximum QT interval,QTcmax）、校正QT间期离散度（Corrected QT interval dispersion,QTcd）延长（P<0.05）。随访84（45，127）d，无反应组较有反应组QTmax、QTd、QTcmax、校正最小QT间期（Corrected minimum QT interval,QTcmin）、QTcd延长（P<0.05）。（2）诊断效能：QTmax、QTmin、QTd、QTcmax、QTcd对儿童及青少年VVS-CI有诊断价值（P<0.001）。QTd的曲线下面积（Area under the curve,AUC）最大（0.914），最佳截断值为28.50 ms，诊断VVS-CI的灵敏度为86.30%，特异度为84.95%。（3）预后估测价值：QTmax、QTd、QTcmax、QTcmin、QTcd对儿童及青少年VVS-CI预后有估测价值（P<0.05或0.01）。QTd的AUC最大（0.906），最佳截断值为34.50 ms，预测对VVS-CI干预有反应的灵敏度为90.00%，特异度为82.35%。结论 心电图QTd对儿童及青少年 VVS-CI的诊断及预后有较好的估测价值。

Objective: Situational syncope is a subtype of neurally mediated syncope and associated with specific circumstances. This paper is to assess the clinical characteristics and underlying causes of situational syncope.Methods: This is a retrospective study of patients who underwent head-up tilt testing (HUTT). Medical records including age at HUTT, gender, number of syncopal episodes, family history of syncope, triggers before the syncopal episode, position during the syncopal episode and the responses to HUTT were reviewed.Results: Among 3140 patients, 354 patients (mean age 28.3 ± 16.6 years old, with 184 males and 170 females) were diagnosed with situational syncope. The causes of situational syncope included micturition (50.85%), defecation (15.82%), bathing (10.45%), swallowing (6.50%), cough (4.80%), post-dinner (3.95%), singing (3.11%), teeth brushing (2.26%), and hair grooming (2.26%). Patients with syncope triggered by micturition, cough, post-dinner were more likely to be men, while those caused by bathing, swallowing, singing, teeth brushing and hair grooming were more likely to be women. 34.75% of patients with situational syncope were between theagesof10–19 yearsold,and20.34%werebetweentheagesof40–49years old.74.01%ofsituationalsyncopal events occurred in an upright position. 47.74% of patients had positive responses to HUTT.Conclusions: These findings show that micturition was the most common cause of situational syncope in both children and adults. There were significant gender and age differences among situational syncope triggered by different causes. Most of situational syncope occurred in the upright position and nearly half of the patients had positive responses to HUTT.

Objectives Head-up tilt test (HUTT) is a useful tool to assess autonomic function and reproduce neurally mediated reflex. In this present study, we evaluated the use of HUTT in pediatric patients aged 3 to 5 years old with orthostatic intolerance.Materials and Methods The medical history and HUTT records of 345 (180 males, aged from 3 to 5 years old) cases of patients who complained symptom of orthostatic intolerance and visited Syncope Ward, Children’s Medical Center, the Second Xiangya Hospital, Central South University from January 2003 to December 2019 were retrospectively reviewed.Results 79 (22.9%) cases had positive responses to complete HUTT (basic HUTT and sublingual nitroglycerin HUTT), while 29 (8.4%) cases had positive responses if only basic HUTT was performed. Sublingual nitroglycerin provocation significantly increased the positive rate of the test (x2=27.565, P＜0.001).The most frequent hemodynamic response to HUTT was vasoinhibitory type vasovagal syncope (12.2%). Syncope (28.7%) and dizziness (22.6%) were the most common symptoms. 8 cases discontinued the test due to intolerable symptoms without severe adverse events occurring.Conclusions HUTT was safe and well tolerated, and could be used to diagnose hemodynamic type of orthostatic intolerance in children aged 3 to 5 years old.

Objectives: Syncope is a common clinical symptom, while there are less relevant literature and targeted research on childhood morbidity. This article will make a cross-section survey on the incidence of syncope in children and adolescents aged 2-18 years in Changsha. Materials and Methods: 4352 children and adolescents aged 2-18 years were randomly selected from 6 primary and secondary schools and 3 kindergartens in Changsha from March 2018 to November 2018. 4916 standardized questionnaires were issued, and 4352 (88.53%) valid questionnaires were recovered. Results: (1) Incidence: 17.37% children and adolescents aged 2-18 years who had at least more than one syncope, the incidence in the adolescence (28.85%) was higher than that in the school age (8.32%) and in the preschool age (2.71%) (P<0.01). (2) Age of onset: 13.9±3.1 years old, with a peak age of 16 years. (3) Gender difference: The incidence of adolescence females was higher than that in males (31.72% vs. 26.25%, P<0.05). In inducements, females were higher than males in sweltering environment (P<0.01), while males were higher than females in urination (P<0.05). Dizziness, nausea, sweating and facial pallor were higher in females than males in presyncope (P<0.05). Conclusions: The incidence of syncope in children and adolescents aged 2-18 years in Changsha is 17.37%. The incidence of syncope is different between males and females in different age groups, there are gender differences in syncope inducements and presyncope.

Background. Oral rehydration salt (ORS) is a first-line medication for vasovagal syncope (VVS) in children and adolescents. We retrospectively investigated the treatment with ORS-I (Na 90 mmol/L) for VVS in children and adolescents to define appropriate duration of treatment.Methods. All patients with a diagnosis of VVS, based on the first head-up tilt test (HUTT) response, and who accepted ORS-I treatment were enrolled. ORS was stopped when the HUTT response turned negative. Patients were followed for six months after cessation of ORS treatment.Results. The study group included 129 patients (57 male, 72 female; mean age, 11.8 ± 2.0 years, age range, 7.0- 17.0 years). Median duration of VVS was 4 months (range, 1 week to >10 years). The number of syncope ranged from 2 times to >20 times. Mean follow-up time was 27.8 ± 6.9 weeks (range, 26-33 weeks). It took to 2~13 weeks for HUTT response to turn negative, with an average time of 8.4 weeks (95% confidence interval, 6.89~9.84 weeks). There was no statistical difference for the time to negative HUTT response according to age groups (<12-year-old vs. ≥12-year-old), syncope type (vasodepressor vs. mixed), and the syncope frequency. No patient experienced syncope after cessation of ORS treatment.Conclusions. Our findings suggest that ORS-I is an effective measure to treat children and adolescents with VVS. We recommend a treatment course of 2 months.