QT间期离散度对儿童及青少年体位性心动过速综合征预后估测价值

目的　探讨QT间期离散度（QTd）对儿童及青少年体位性心动过速综合征（POTS）的预后估测价值。方法　选取2012年7月至2020年5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POTS的儿童及青少年75例为POTS组,匹配同期在本院进行健康检查的儿童及青少年75例为对照组。测量两组基础状态下12导联心电图QT间期,计算QT间期离散度（QTd）。采用SPSS ?22.0统计软件进行数据处理。结果　（1）两组比较：POTS组较对照组最大QT间期（QTmax）、最小QT间期（QTmin）、QTd、校正最大QT间期（QTcmax）、校正最小QT间期（QTcmin）、校正QT间期离散度（QTcd）延长（P＜0.001或0.05）。（2）预后估测价值：POTS组干预后随访55（36,114） d,有反应组较无反应组QTd、QTcd延长（P＜0.001）。QTd的AUC最大（0.910）,其最佳截断值为30.00 ms时,预测对POTS干预有反应的灵敏度为82.90%,特异度为81.78%。结论　心电图QTd对儿童及青少年POTS的预后有较好的估测价值。     

血管迷走性晕厥儿童卧位、立位QT间期离散度及P波离散度的变化

目的探讨血管迷走性晕厥(VVS)儿童卧、立位QT间期离散度(QTd)及P波离散度(Pd)的变化。方法直立倾斜试验(HUTT)阳性的VVS患儿46例为研究组。年龄7~17岁,平均(11.91±2.09)岁。用SR-1000A心电综合自动分析仪描记卧位及立位12导联同步体表心电图(12ECG)。匹配健康儿童30例为对照组。选择窦性心律波形清晰的12ECG3个心动周期,测量心率(HR)、QTd与Pd,按Bazete公式校正心率后得出QTcmax、QTcmin、QTcd、Pcmax、Pcmin、Pcd。结果1.对照组卧位较立位最大QT间期(QTmax)、最小QT间期(QTmin)、最大P波时间(Pmax)均明显延长(Pa<0.01),最小P波时间(Pmin)缩短(P<0.05),Pd延长(P<0.05),QTd、QTcmax、QTcmin、QTcd、Pcmax、Pcmin、Pcd未见明显变化(Pa>0.05)。2.研究组卧位较立位QTmax、QTmin、QTd、QTcd、Pmax、Pd、Pcd明显延长(Pa<0.01),Pcmax延长(P<0.05),Pcmin明显缩短(P<0.01),QTcmax、QTcmin、Pmin未见明显变化(Pa>0.05)。3.研究组较对照组卧位QTmax、QTcmax、Pcd延长(Pa<0.05),QTd、QTcd、Pmax、Pcmax延长(Pa<0.01);立位Pcd延长(Pa<0.05),Pmax、Pcmax延长(Pa<0.01)。4.研究组较对照组卧位时HR稍降低(P>0.05),立位时HR明显增加(P<0·01),HR增加在研究组与对照组比较未见差异(分别增加15.29次/minvs12.57次/min,P>0.05)。5.VVS患儿在血管抑制型和混合型时卧、立位的QTd及Pd未见差异(Pa>0.05)。6.VVS患儿在卧位、立位时QTd及Pd不存在男女性别差异(Pa>0·05)。结论VVS患儿卧位时更易发生心律失常;当体位改变时QTd、Pd明显受自主神经功能影响,表明该法对心脏自主神经功能的评价具有指导价值。     

自主神经功能检测对体位性心动过速综合征的诊断价值

目的 探讨自主神经功能检测对体位性心动过速综合征(POTS)的诊断价值.方法 对POTS患儿26例和健康儿童20例分别测定其瓦式(Valsalva )比值、深呼吸心率差、30 s最长RR间期/15 s最短RR 间期(30/15)比值、卧立位血压差等自主神经功能及12 导联同步体表心电图(12 ECG)QT间期离散度(QTd)、P波离散度(Pd)水平的变化.采用SPSS 13.0软件进行统计学分析.结果 POTS患儿Valsalva比值、深呼吸心率差与健康对照组比较[Valsalva比值:(1.08±0.06) vs (1.22±0.03); 深呼吸心率差:(9.7±1.7) 次·min-1 vs (18.3±1.6)次·min-1] 均明显降低,差异均有统计学意义(t=5.86、11.34,Pa<0.05).与健康对照组比较,POTS患儿最大QT间期(QTmax)、最小QT间期(QTmin)、QTd延长(Pa<0.01),心率校正后最大QT间期(QTcmax)、心率校正后QT间期离散度(QTcd)增大(Pa<0.01,<0.05),而心率校正后最小QT间期(QTcmin)二组比较无统计学差异;二组最大P波时间(Pmax)、最小P波时间(Pmin)、心率校正后最大P波(Pcmax)、心率核正后最小P波(Pcmin)、Pd及心率校正后P波离散度(Pcd)比较,差异均无统计学意义(Pa>0.05).结论 POTS患儿自主神经明显受损,Valsalva比值、深呼吸心率差、QTd可作为诊断POTS的一种新方法.     

儿童血管迷走性晕厥QT离散度分析

目的 了解儿童血管迷走性晕厥QT离散度(QTd)的变化。方法 对24例血管迷走性晕厥患儿及18例健康儿童的QTd进行测量。结果 血管迷走性晕厥患儿QTd、QTcd、QTmax较对照组显著增大，差异具有显著性。结论 血管迷走性晕厥患儿QTd明显延长。QTd的分析对了解血管迷走性晕厥患儿的心电生理特点、辅助临床对晕厥患儿的鉴别诊断具有重要意义。     

儿童血管迷走性晕厥QT间期离散度及心率变异性分析

目的探讨儿童血管迷走性晕厥（VVS）QT间期离散度（QTd）及心率变异性（HRV）的变化。方法采用日本光电9320K12导联同步心电图机及DeMar-K100动态心电图仪对52例VVS患儿及30例健康儿童的QTd及HRV进行测量。结果VVS患儿QTd、校正QT间期离散度和最长QT间期较对照组显著增大，差异具有显著性；直立倾斜试验（HUTT）阳性组和阴性组间QTd值比较差异无显著性。SDNN、SDANN及RMSSD病例组较对照组减小，且病例组SDNN、RMSSD与对照组相比差异有显著性；HUTT阳性组和阴性组间HRV差异无显著性。结论VVS的发病机制与交感神经和副交感神经调节存在障碍有关。HUTT作为诊断VVS的金标准，其阴性者不能除外VVS。QTd、HRV对于VVS患儿发生心肌缺血、心律失常等心血管事件具有一定的预测价值。     

儿童青少年心脏抑制型血管迷走性晕厥心电图P波的变化及诊断价值

目的 探讨儿童青少年心脏抑制型血管迷走性晕厥（VVS-CI）心电图P波的变化及诊断价值。方法 选择43例明确诊断的VVS-CI儿童青少年为VVS-CI组，同期选取43例健康儿童青少年为对照组。测量两组基础状态下12导联心电图P波时限和电压，并分析其变化特点。结果 VVS-CI组心率低于对照组（P < 0.05），VVS-CI组P波时间（Pwd）、P波最大时间（Pmax）、P波离散度（Pd）、校正P波最大时间（Pcmax）、校正P波离散度（Pcd）较对照组延长（P < 0.05）。Pwd、Pmax、Pd、Pcmax、Pcd对儿童青少年VVS-CI有诊断价值（P < 0.05）。Pwd最佳截断值为78.49 ms，灵敏度为69.77%，特异度为83.72%；Pmax最佳截断值为93.39 ms，灵敏度为76.74%，特异度为90.70%；Pd最佳截断值为27.42 ms，灵敏度为95.35%，特异度为69.77%；Pcmax最佳截断值为120.90 ms，灵敏度为46.51%，特异度为88.37%；Pcd最佳截断值为36.37 ms，灵敏度为83.72%，特异度为72.09%。结论 儿童青少年VVS-CI的Pwd、Pmax、Pd、Pcmax、Pcd明显延长，提示可能存在心房电活动异常。P波界值对儿童青少年VVS-CI具有诊断价值。     

单纯室间隔缺损介入封堵术后左心室电压和QT间期QT离散度变化研究

目的观察单纯室间隔缺损(VSD)患儿介入封堵缺损前后心电图左室电压和QT间期、QT离散度(QTd)的变化。方法以2014年1月至2015年1月到四川大学华西第二医院儿科心脏介入治疗中心接受以对称型VSD封堵器介入封堵的VSD患儿作为研究对象,收集患儿心电图资料,对90例接受经皮VSD封堵术且手术前后均未发生心律失常患儿的术前、术后1、3、5 d及1个月心电图的RV5(V5导联R波)、SV1(V1导联S波)、(RV5+SV1)电压和QT间期、心率校正的QT间期(QTc)、QTd及心率校正的QT离散度(QTcd)进行分析。结果 VSD封堵后左室电压(RV5+SV1)降低,且在术后第3天后均与术前差异有统计学意义(P0.05);QTc在术后第5天之后与术前差异有统计学意义(P0.05);QTd和QTcd在术后1个月与术前、术后1 d比较差异有统计学意义(P0.05)。胸导联RV5、SV1电压及QT间期在术前、术后1、3、5 d和1个月的比较差异无统计学意义(P0.05)。结论接受经皮VSD封堵术且手术前后均未发生心律失常的患儿术后左室电压会逐渐降低,QTc、QTd和QTcd会有缩短。     

病毒性心肌炎Q-T离散度探讨

目的 了解小儿病毒性心肌炎的Q－T离散度（QTd)变化及相关因素。方法 对26例病毒性心肌炎患儿急性期、症状消除后及29例健康对照儿童的QTd进行测量。结果 病例组急性期QTd、QTcd、QTmax较正常对照组显著增大。19例治疗前后的QTd比较，显示临床表现消失后的QTd和QTcd值明显降低。结论 病毒性心肌炎的QTd改变确实存在，且与其心肌损害程度关系密切。     

儿童室间隔缺损封堵术后早期完全性左束支传导阻滞心电图相关指标的变化

目的观察单纯室间隔缺损(VSD)患儿介入封堵术后早期发生完全性左束支传导阻滞(CLBBB)患儿的心电图变化。方法纳入21例行膜周部VSD介入封堵且术后早期出现CLBBB的患儿,同时以性别、年龄及封堵器大小进行1:1配对,纳入同时期术后未合并任何心律失常的单纯膜周部VSD的患儿21例作为对照组。比较两组患儿组间及组内术前、术后1 d、术后3 d、术后5 d、术后30 d心电图左室电压、QT间期、心率校正的QT间期(QTc)、QT离散度(QTd)、心率校正的QT离散度(QTcd)、JT离散度(JTd)和心率校正的JT离散度(JTcd)的变化。结果两组患儿左室电压、JTcd随手术时间的变化而变化(P0.05);左室电压及QTd变化存在时间因素与分组因素的交互效应(P0.05);CLBBB组与对照组的JTcd比较差异有统计学意义(P0.05);CLBBB组与对照组的左室电压在术后3 d和术后5 d组间比较差异有统计学意义(P0.05)。结论 VSD患儿介入封堵术后有无CLBBB者早期心电图指标左室电压和JTcd有差异,其中JTcd可能对预测术后早期CLBBB的发生有参考作用。     

新生儿缺氧缺血性心脏损害QT间期离散度及血清CK-MB的变化及预后分析

为探讨新生儿缺氧缺血心脏损害(HIM)患儿QT间期离散度(QTcd)和血清肌酸激酶同功酶B(CK-MB)的动态变化及对HIM预后的影响.采用对63例HIM患儿发病48h内和治疗7d后QTcd和CK-MB进行检测,并与30例无窒息新生儿对照比较.结果显示HIM组与对照组比较,患儿发病48h内QTcd及CK-MB均显著升高(P＜0.01).经7d治疗后,HIM患儿QTcd及CK-MB均显著下降,产后缺氧组较胎儿期缺氧缺血组下降更显著(P＜0.05),且胎儿期缺氧缺血组并发症多,预后差(P＜0.05).结论QTcd及CK-MB相结合可作为HIM的特异性敏感指标,对判断HIM预后有益.     

QT dispersion in infants with apparent life-threatening events syndrome

Apparent life-threatening event (ALTE) is a term used to define an event of unknown cause after an infant is found limp, cyanotic, bradycardic, and/or requires resuscitation. Eight to 15% of children with ALTE die of sudden infant death syndrome. Obstructive sleep apnea, bradycardia, gastroesophageal reflux, and laryngotracheal abnormalities are frequently associated with ALTE. Wide QT dispersion is associated with sudden death in heart failure and increased risk of ventricular fibrillation in acute myocardial infarction. Here, we assess QT dispersion in infants with ALTE and its correlation to clinical and electrocardiographic indices. The study included eighty nine infants (age 2.14 ± 1.8 months, 46 males and 43 females) referred with ALTE to the pediatric emergency room and 18 controls (age 2.77 ± 2.2 months) who underwent electrocardiogram assessment of QTmin, QTmax, QT dispersion (QT-D), and as well as QTmin, QTmax, and QT-D corrected for heart rate (QTcmin, QTcmax, QTC-D, respectively). All infants were referred at the usual diagnostic tests—the gastroesophageal reflux test, apnea monitoring, Holter ECG monitoring, electroencephalogram, and Doppler echocardiography. QT-D, QTc-D, and QTc-min were significantly greater in the ALTE group (p <0.01). Greater QTc-D was found in males compared to females (p <0.001). QT-D and QTc-D showed little or no correlation with age of infant or positivity of diagnostic tests. QTc has been found by multiple regression analysis to be the independent variable with the greatest impact on QTc-D (beta = -0.68, p <0.001).     

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??Objective To observe the changes of left ventricular voltage??QT interval and QT interval dispersion before and after transcatheter closure for simple ventricular septal defect. Methods The ECG RV5 ??V5 lead r waves????SV1 ??V1-lead s-wave??????RV5+SV1?? voltage??QT interval and corrected QT interval??QT dispersion ??QTd?? and heart rate corrected QT dispersion ??QTcd?? were analyzed in 90 VSD children without arhythmia before transcatheter closure or 1??3??5 days and 1 month after it. All the patients were admitted between January 2014 and January 2015 in Department of Pediatrics West China Second University Hospital of Sichuan University. Results Left ventricular voltage after transcatheter closure for ventricular septal defect ??RV5+SV1?? decreased??being with statistical significance on the third day after operation when compared with the preoperative one ??P??0.05????there were significant differences in QTc before and on the fifth day after operation ??P??0.05??. QTd and QTcd one month after surgery??compared with preoperative and postoperative day??had statistically significant difference ??P ?? 0.05??. Precordial leads RV5??SV1 voltage and QT interval in the preoperative??postoperative 1??3??5 days??1 month??had no statistically significant difference??P??0.05??. Conclusion Cardiac arrhythmia doesn’t occur in simple ventricular septal defect in children after transcatheter closure??and left ventricular voltage will be gradually reduced??corrected QT interval??QTd and QTcd will be shortened.     

Increased QT dispersion in epileptic children

AIM: Epilepsy is a common paroxysmal disorder in childhood. Tachyarrhythmia, bradyarrhythmia, asystole, atrioventricular block, ventricular fibrillation or sudden death may occur during seizures. Mutations of ion-channel coding genes are found in patients with idiopathic or cryptogenic epilepsy. The ion channels also play a role in arrhythmogenesis. QT dispersion is a non-invasive method for assessment of regional repolarization differences within the myocardial tissue. This study investigated QT and QTc dispersion (QTcd) and the risk of dysrhythmia in epileptic children. METHODS: The first group included 28 patients with newly diagnosed epilepsy and not taking antiepileptic treatment (range 10 mo to 15 y, mean +/- SD 6.86 +/- 3.92 y), the second group included 34 patients taking antiepileptic treatment (range 1-14 y, mean +/- SD 7.51 +/- 3.68 y) and the control group included 52 healthy children (range 4 mo to 15 y, mean +/- SD 6.94 +/- 3.92 y). Twelve-lead ECGs were obtained and heart rate, RR interval, P wave amplitude and duration, PR interval, QRS duration, QRS axis and QT intervals were measured, and QTc, QTd, QTcd were calculated in all subjects. The measurements were repeated in the first group under antiepileptic treatment. RESULTS: While no significant difference in terms of heart rate, RR interval, P wave amplitude and duration, PR interval, QRS duration, QRS axis, QT intervals or QTc intervals was found, QTd and QTcd values were significantly increased in epileptic children compared with the control group. QTd was 58.1 +/- 13.4 ms and 35.9 +/- 9.3 ms and QTcd was 91.0 +/- 22.9 and 68.6 +/- 18.0ms in patients and controls, respectively. Antiepileptic treatment did not affect QT dispersion. CONCLUSION: QT dispersion is increased in epileptic children. Further investigation is needed to reveal the pathogenesis of myocardial repolarization abnormalities in epileptic patients.     

PRESENCE OF PROLONGED DISPERSION OF QT INTERVALS IN LATE SURVIVORS OF CHILDHOOD ANTHRACYCLINE THERAPY

To determine the incidence of abnormal dispersion of QT intervals on an ECG the authors measured these intervals in long-term survivors after anthracycline treatment for childhood malignancies and compared the incidence to the traditional markers, prolonged QT and QTc intervals. Prolonged QT dispersion (QTd) and corrected QT dispersion (QTcd) have been associated with serious arrhythmias and sudden death in many forms of heart disease. The above intervals and shortening fraction (SF) on echocardiogram were determined in 64 late survivors who were 4-22 years post anthracycline therapy. They were divided into 2 groups: group I, 39 patients with normal function with SF &#83 29%, and group II, 15 patients with SF < 29%. An additional 10 patients had died and had SF < 29% at the time of death. They were divided into 2 groups: group III, 5 patients who died with heart failure after a mean of 12 years from of therapy, and group IV, 5 patients who had a sudden cardiac death after a mean of 9 years from end of therapy. In group I patients, the incidence of prolonged QT and QTc intervals was < 6%, whereas that of QTd and QTcd was > 38%. In group II patients, the presence of prolonged QT and QTc inter vals was < 16%, whereas that of QTd and QTcd was > 40%. The QTc ( p = .01), QTd ( p = .02), and QTcd ( p = .01) were significantly higher and SF (<.01) significantly lower in group IV compared to those alive (group I and II patients) with no significant difference in age, number of years of follow-up, precordial radiation dose, or anthracycline dose between the two. The combination of QTcd > 110 ms and diminished SF < 29% was found to be associated with sudden death. In summary, the long-term survivors of anthracycline therapy had a high incidence (>38%) of abnormally prolonged QT dispersion intervals, QTd and QTcd, even in those with normal QT and QTc on an ECG and normal shortening fraction on an echocardiogram.     

Presence of prolonged dispersion of qt intervals in late survivors of childhood anthracycline therapy

To determine the incidence of abnormal dispersion of QT intervals on an ECG the authors measured these intervals in long-term survivors after anthracycline treatment for childhood malignancies and compared the incidence to the traditional markers, prolonged QT and QTc intervals. Prolonged QT dispersion (QTd) and corrected QT dispersion (QTcd) have been associated with serious arrhythmias and sudden death in many forms of heart disease. The above intervals and shortening fraction (SF) on echocardiogram were determined in 64 late survivors who were 4-22 years post anthracycline therapy. They were divided into 2 groups: group I, 39 patients with normal function with SF >or= 29%, and group II, 15 patients with SF < 29%. An additional 10 patients had died and had SF < 29% at the time of death. They were divided into 2 groups: group III, 5 patients who died with heart failure after a mean of 12 years from of therapy, and group IV, 5 patients who had a sudden cardiac death after a mean of 9 years from end of therapy. In group I patients, the incidence of prolonged QT and QTc intervals was < 6%, whereas that of QTd and QTcd was > 38%. In group II patients, the presence of prolonged QT and QTc intervals was < 16%, whereas that of QTd and QTcd was > 40%. The QTc (p =.01), QTd (p =.02), and QTcd (p =.01) were significantly higher and SF (<.01) significantly lower in group IV compared to those alive (group I and II patients) with no significant difference in age, number of years of follow-up, precordial radiation dose, or anthracycline dose between the two. The combination of QTcd > 110 ms and diminished SF < 29% was found to be associated with sudden death. In summary, the long-term survivors of anthracycline therapy had a high incidence (>38%) of abnormally prolonged QT dispersion intervals, QTd and QTcd, even in those with normal QT and QTc on an ECG and normal shortening fraction on an echocardiogram.     

Standard dose of inhaled albuterol significantly increases QT dispersion compared to low dose of albuterol plus ipratropium bromide therapy in moderate to severe acute asthma attacks in children

BACKGROUND: Beta-2 agonist therapy has previously shown to increase the QT dispersion (QTd) in asthmatic patients and increased QTd has been well documented in association with cardiac arrhythmias and sudden death. However, the data concerning the effect of low doses of beta-2 agonist therapy in combination with the anticholinergic agents to potentiate bronchodilatation on QTd in asthmatic children are limited. The objectives of this study was to investigate the changes on QTd during both the standard dose of nebulized albuterol therapy and low dose nebulized albuterol plus inhaled ipratropium therapyn to assess the potential arrhythmogenic risk of these two treatment strategies in children with acute asthmatic attacks. METHODS: Forty-three children with the diagnosis of moderate to severe acute asthma were enrolled in the study. Standard dose of nebulized albuterol therapy (0.15 mg/kg) were administered to 20 patients (group 1) and low dose of nebulized albuterol (0.075 mg/kg) plus nebulized ipratropium bromide therapy (250 microg/dose) were given to the remaining 23 patients (group 2). Respiratory distress score, peak expiratory flow rate, arterial blood pressure, O2 saturation, serum potassium and urea nitrogen levels were studied and QT interval parameters were measured from the standard 12-lead electrocardiograms at baseline and after treatment. RESULTS: Significant improvement was achieved in respiratory distress score and peak expiratory flow rate after three dose inhalation. No significant difference was observed between the pre and post-treatment values of serum potassium, blood urea nitrogen, O2 saturation and arterial blood pressure values. The evaluation of the corrected QTd (QTcd) showed that while there was no statistical difference in the pre and post-treatment values in group 2 (30.4+/-3.1 msn vs 32.1+/-3.9 msn), QTcd was found to be significantly increased in group 1 after treatment (29.0+/-3 msn vs 40.6+/-5.1 msn, P<0.0001). CONCLUSION: The data of the present study suggest that the increase of the QTd is more prominent with the use of a standard dose of albuterol compared to low dose albuterol plus ipratropium therapy. Therefore, it may be concluded that a low dose of albuterol plus ipratropium bromide therapy may be preferred to avoid rhythm disturbances in asthmatic children.