Background: Malignant vasovagal syncope (VVS) is characterized by cardiac arrest lasting more than 3 seconds during a syncope episode or head-up tilt test (HUTT). We aim to conduct a risk assessment for potential malignant VVS before the HUTT by using economic, simple and convenient demographic data, in order to prevent adverse outcomes for pediatric VVS.Purpose: To explore the correlation between demographic factors and pediatric malignant VVS, and verify the value of these factors in early risk assessment for malignant VVS before HUTT, so as to optimize test safety and reduce adverse events. Methods: We conducted a retrospective analysis of the clinical data of 3,734 children who were initially diagnosed with VVS due to unexplained syncope and presyncope. Finally, 122 children who met the diagnostic criteria for malignant VVS were included in the malignant VVS group, and 661 children who did not meet the criteria during the same period were matched as the control group. By analyzing demographic data and other factors, we attempted to clarify the association between these factors and malignant VVS. Results: Linear relationship: age and body mass index (BMI) have independent protective effects on malignant VVS. For every 1-year increase in age and every 1 kg/m2 increase in BMI, the risk of malignant VVS decreases by 12% and 9%, respectively. Nonlinear relationship: When the age is <12.9 years old, for every additional year of age, the risk of malignant VVS decreases by 20%. For ages 12.9 years and above, the efficacy is not significant. There is no significant nonlinear relationship between BMI and malignant VVS. Conclusion Age and BMI are independent protective factors for pediatric malignant VVS. Before the age of 12.9 years, the incidence of malignant VVS gradually decreases with the increase in age, and thereafter there is no significant impact.

This revised guideline incorporates recent advances in neurally mediated syncope (NMS) in children, providing a timely update to the " 2018 CPCS Guidelines for Diagnosis and Treatment of Syncope in Children and Adolescents" . In the spectrum of NMS-related disorders and diagnosis, this revision includes additional postural tests, introduces the new concept of sitting tachycardia syndrome and sitting hypertension, and emphasizes the diagnosis and assessment of comorbidities.The clinical diagnosis of NMS in children and adolescents requires a combination of detailed history taking, thorough physical examination, correct interpretation of postural tests results, and comprehensive assessment of comorbidities.In terms of treatment, detailed recommendations are given for non-pharmacological therapy, emphasizing the use of biomarkers to guide individualized treatment and the management of comorbidities.The revised guideline also provides specific recommendations for follow-up and outcome assessment of NMS in children and adolescents.

This revised guideline incorporates recent advances in neurally mediated syncope (NMS) in children, providing a timely update to the " 2018 CPCS Guidelines for Diagnosis and Treatment of Syncope in Children and Adolescents" . In the spectrum of NMS-related disorders and diagnosis, this revision includes additional postural tests, introduces the new concept of sitting tachycardia syndrome and sitting hypertension, and emphasizes the diagnosis and assessment of comorbidities.The clinical diagnosis of NMS in children and adolescents requires a combination of detailed history taking, thorough physical examination, correct interpretation of postural tests results, and comprehensive assessment of comorbidities.In terms of treatment, detailed recommendations are given for non-pharmacological therapy, emphasizing the use of biomarkers to guide individualized treatment and the management of comorbidities.The revised guideline also provides specific recommendations for follow-up and outcome assessment of NMS in children and adolescents.

Background::Substantial progress in air pollution control has brought considerable health benefits in China, but little is known about the spatio-temporal trends of economic burden from air pollution. This study aimed to explore their spatio-temporal features of disease burden from air pollution in China to provide policy recommendations for efficiently reducing the air pollution and related disease burden in an era of a growing economy.Methods::Using the Global Burden of Disease method and willingness to pay method, we estimated fine particulate matter (PM 2.5) and/or ozone (O 3) related premature mortality and its economic burden across China, and explored their spatio-temporal trends between 2005 and 2017. Results::In 2017, we estimated that the premature mortality and economic burden related to the two pollutants were RMB 0.94 million (68.49 per 100,000) and 1170.31 billion yuan (1.41% of the national gross domestic product [GDP]), respectively. From 2005 to 2017, the total premature mortality was decreasing with the air quality improvement, but the economic burden was increasing along with the economic growth. And the economic growth has contributed more to the growth of economic costs than the economic burden decrease brought by the air quality improvement. The premature mortality and economic burden from O 3 in the total loss from the two pollutants was substantially lower than that of PM 2.5, but it was rapidly growing. The O 3-contribution was highest in the Yangtze River Delta region, the Fen-Wei Plain region, and some western regions. The proportion of economic burden from PM 2.5 and O 3 to GDP significantly declined from 2005 to 2017 and showed a decreasing trend pattern from northeast to southwest. Conclusion::The disease burden from O 3 is lower than that of PM 2.5, the O 3-contribution has a significantly increasing trend with the growth of economy and O 3 concentration.

Objective:To analyze the duration of the second stage of labor without epidural anesthesia and its association with pregnancy outcome.Methods:This retrospective study involved 12 789 women who delivered without epidural anesthesia in the First Affiliated Hospital of Kunming Medical University from January 1, 2014 to December 31, 2017. These subjects were divided into primipara group (9 517 cases) and multipara group (3 272 cases). Demographic characteristics, maternal and neonatal outcomes and the duration of the second stage of labor were compared between the two groups using two independent samples t-test, Mann-Whitney U test and Chi-square test (Fisher's exact test). Differences in the maternal and neonatal outcomes were also analyzed among different subgroups in primiparae [length of second stage: <1 h group ( n=6 265), ≥1-2 h group ( n=2 305), ≥2-3 h group ( n=831) and ≥3 h group ( n=116)] and multiparae [length of second stage <1 h group ( n=3 144), ≥1-2 h group ( n=102) and ≥2 h group ( n=26)]. The association between second stage length and pregnancy outcomes was analyzed with Cramer's V. After adjusted for maternal age, gestational weeks at delivery, body mass index before pregnancy, complications during pregnancy and neonatal birth weight, the relationship between the duration of the second stage and adverse outcomes was analyzed by binary logistic regression analysis. Results:The 95 th percentile of the second-stage labor duration was 143 min for primiparae and 52 min for multiparae. The rates of vaginal delivery, forceps delivery, cesarean section in the second stage, episiotomy, third- or fourth-degree perineal laceration, postpartum hemorrhage, grade Ⅱ postpartum hemorrhage, transfusion, umbilical arterial blood gas pH<7.15 and transferring to neonatal intensive care unit (NICU) were all correlated with the duration of second stage in primiparae (Cramer's V values: 0.22, 0.23, 0.03, 0.22, 0.05, 0.10, 0.03, 0.03, 0.03 and 0.07, respectively, all P<0.05), and so did those of vaginal delivery, forceps delivery, episiotomy, postpartum hemorrhage, grade Ⅱ postpartum hemorrhage, transfusion and transferring to NICU in multiparae (Cramer's V values: 0.18, 0.19, 0.28, 0.14, 0.09, 0.13 and 0.06, respectively, all P<0.05). Logistic analysis showed that in primiparae, the duration of second stage >1 h was an independent risk factor for episiotomy, third- or fourth-degree perineum laceration, forceps delivery, postpartum hemorrhage, admission to NICU and umbilical arterial blood gas pH<7.15 [adjusted OR (95% CI): 2.080 (1.907-2.268), 1.773 (1.080-2.911), 1.625 (1.420-1.859), 1.365 (1.231- 1.514), 1.305 (1.165-1.462) and 1.246 (1.081-1.436), respectively], while second stage length >2 h was the independent risk factor for episiotomy, forceps delivery, third- or fourth-degree perineum laceration, postpartum hemorrhage, grade Ⅱ postpartum hemorrhage, blood transfusion, admission to NICU and umbilical arterial blood gas pH<7.15 [adjusted OR (95% CI): 4.844 (4.132-5.678), 4.223 (3.571-4.993), 3.289 (1.806-5.989), 1.952 (1.675-2.274), 1.781 (1.057-3.001), 1.654 (1.025-2.668), 1.682 (1.421-1.991) and 1.298 (1.039-1.620), respectively]. In multiparae, the length of second stage >1 h was an independent risk factor for episiotomy, blood transfusion, forceps delivery, postpartum hemorrhage and admission to NICU [adjusted OR (95% CI): 8.796 (5.717-13.534), 7.469 (2.874-19.411), 6.135 (3.217-11.699), 2.697 (1.624-4.477) and 1.814 (1.063-3.097), respectively], while the duration of second stage >2 h was the independent risk factor for episiotomy, third- or fourth-degree perineum laceration, blood transfusion, grade Ⅱ postpartum hemorrhage, forceps delivery and postpartum hemorrhage [adjusted OR (95% CI): 38.868 (14.948-101.063), 28.046 (2.780-282.490), 20.076 (5.384-74.866), 16.327 (3.406-78.274), 14.337 (5.351-38.411) and 9.036 (3.880-21.011), respectively]. Conclusions:The duration of the second stage of labor without epidural anesthesia is between that reported by Friedman and by Zhang. A prolonged second stage of labor may increase the risk of adverse pregnancy outcomes.

Objective:To investigate the relationship between body mass index (BMI) and response time of cardioinhibitory type vasovagal syncope (VVS-CI) in children.Methods:The clinical data of 56 children with syncope or pre-syncope were retrospectively analyzed and they visited specialist clinic for syncope and were diagnosed as VVS-CI in the Second Xiangya Hospital, Central South University from December 2012 to September 2019.Based on height and weight, BMI was calculated, and divided into low BMI group (35 cases) and normal BMI group (21 cases). Between the 2 groups, baseline heart rate, head-up tilt test (HUTT) positive response heart rate, baseline head-up tilt test (BHUT) positive response time, and sublingual nitroglycerin-provocated HUTT (SNHUT) positive response time were compared.The correlation between BMI and positive response time was analyzed.SPSS 22.0 software was applied for statistical analysis.Results:There were no significant differences in age, sex, duration of disease and number of syncope between the 2 groups (all P>0.05). No significant differences were found in baseline heart rate and positive response heart rate between the 2 groups [(78.5±15.3) times/min vs.(72.8±8.7) times/min, t=1.223, P=0.230; (44.0±13.9) times/min vs.(47.0±10.0) times/min, t=-0.664, P=0.511]. Compared with normal BMI group, BHUT positive patients/SNHUT positive patients were higher in low BMI group (27/8 cases vs.9/12 cases, χ2=4.839, P=0.027), and the positive response time of BHUT was shorter [(13.1±4.6) min vs.(23.7±9.5) min, t=-2.691, P=0.023]. There were no significant differences in SNHUT positive response time between the 2 groups ( P>0.05). Low BMI was correlated with BHUT positive response time ( r=0.750, P=0.005). Normal BMI was not associated with BHUT positive response time ( r=0.316, P=0.217). There was no correlation between low BMI and normal BMI and SNHUT positive response time ( r=0.177, P=0.431; r=0.021, P=0.940). Conclusions:Low BMI is positively correlated with BHUT positive response time of children with VVS-CI.The time it takes for syncope occurrence was shorter in children with low BMI than that in normal BMI.

Objective:To investigate the circadian rhythm of blood pressure and morning blood pressure surge (MBPS) in children with neurally mediated syncope (NMS).Methods:From July 2018 to June 2019, 135 cases [aged 3-16 years old (10.12±2.53) years old, with 74 males and 61 females] with unexplained syncope, presyncope, and symptoms such as headache, dizziness, chest pain, and chest tightness were collected in the Second Xiangya Hospital, Central South University for the first time.The 24 hour ambulatory blood pressure monitoring (24 h ABPM) was completed on the same day of the head-up tilt test (HUTT). Patients were divided into HUTT negative and positive groups, and dippers and non-dippers groups. MBPS (sleep-trough surge) was calculated and compared respectively.Results:(1) There were 51 patients in the HUTT positive group, including 27 patients with vasovagal syncope, 23 patients with postural orthostatic tachycardia syndrome, and 1 patient with orthostatic hypotension. In HUTT positive group, there were 22 cases (43.14%) of dippers and 29 cases of non-dippers.There were 84 patients in the HUTT negative group, there were 32 cases (38.10%) of dippers and 52 cases of non-dippers. There were no statistical significances in the dipper proportion between HUTT positive and negative group ( χ2=1.305, P>0.05). (2) Sleep-trough systolic blood pressure (SBP) surge was 1-45 mmHg [(15.97±8.03) mmHg](1 mmHg=0.133 kPa), and sleep-trough diastolic blood pressure (DBP) surge was -6-43 mmHg[(14.05±7.97) mmHg]. There were no statistical significances in sleep-trough surge between the HUTT negative and positive group (all P>0.05). (3) The age in the dipper group was higher than that in the non-dipper group [(10.72±2.20) years old vs. (9.72±2.66) years old, t=2.288, P<0.05]. The daytime average SBP [(110.20±8.33) mmHg vs.(105.54±7.51) mmHg, t=3.381, P<0.01], and morning peak SBP [(109.99±10.19) mmHg vs.(106.63±8.71) mmHg, t=2.045, P<0.05] of the dipper group were higher than those of the non-dipper group.The nighttime average SBP[(95.41±7.50) mmHg vs.(98.59±6.88) mmHg, t=2.540, P<0.01], nighttime average DBP[(48.61±4.52) mmHg vs.(52.28±4.65) mmHg, t=4.547, P<0.01], nocturnal minimum SBP[(89.62±8.18) mmHg vs.(93.60±7.38) mmHg, t=2.940, P<0.01], and nocturnal minimum DBP[(44.99±5.32) mmHg vs.(49.01±5.54) mmHg, t=4.205, P<0.01] of the dipper group were lower than that of the non-dipper group.Nocturnal SBP reduction rate [(13.42±2.68)% vs.(6.48±2.49)%, t=15.384, P<0.01], nocturnal DBP reduction rate[(19.98±4.92)% vs.(12.46±5.05)%, t=8.561, P<0.01], sleep-trough SBP surge[(20.37±8.30) mmHg vs.(13.03±6.36) mmHg, t=5.800, P<0.01], and sleep-trough DBP surge[(16.91±8.06) mmHg vs.(12.13±7.36) mmHg, t=3.554, P<0.01] of the dipper group were higher than those of the non-dipper group. Conclusions:Nocturnal blood pressure reduction and sleep-trough surge decreased in NMS children, and there is a circadian rhythm disorder of blood pressure.

Objective:To analyze the association between the types of response to head-up tilt test (HUTT) and levels of various vitamins in children and adolescents with orthostatic intolerance.Methods:Sixty-five cases of children and adolescents 35 males and 30 females aged 5-14 (10.5±2.0) years old who complained orthostatic intolerance symptoms, including syncope, dizziness, headache, and chest tightness, in Children′s Medical Center, the Se-cond Xiangya Hospital, Central South University between November 2018 and April 2019, were enrolled.By comprehensive history, physical examination, and necessary laboratory testing, heart, cerebrovascular and other system diseases were excluded.According to HUTT result, these patients were divided into 2 groups, namely negative HUTT group and positive HUTT group.The serum levels of vitamin A 1, B 1, B 2, B 6, B 9, B 12, C, and E were compared between the 2 groups.Continuous data were analyzed by conducting t-test and categorical data were analyzed by performing χ2 test. Results:(1) There were 32 cases (18 males and 14 females) in negative HUTT group and 33 cases (17 males and 16 females) in positive HUTT groups, with 28 cases of vaso vagal syncope and 5 cases of postural tachycardia syndrome.There were no significant differences in age, gender ratio, and body mass index between the negative HUTT group and positive HUTT group.(2) The serum level of vitamin B 1 of positive HUTT group was lower than that of negative HUTT group [(77.43±16.70) nmol/L vs.(88.56±18.98) nmol/L, t=-2.513, P<0.05], while the levels of vitamin A 1, B 2, B 6, B 9, B 12, C, and E had no significant differences between the two groups (all P>0.05). Conclusions:Patients with positive responses to HUTT relatively lacked vitamin B 1, suggesting the role of vitamin B 1 in the pathophysiological process of neurally mediated syncope.

Objective:To discuss the relationship between heart rate (HR) and heart rate differences (HRD) at different time points in head-up tilt test (HUTT) and the occurrence of postural tachycardia syndrome(POTS) in children and adolescents.Methods:A total of 217 children and adolescents diagnosed as POTS, who complained of syncope or presyncope, were chosen as POTS group (aged 6 to 16 years). During the same period, 73 healthy children and adolescents with matching gender and age were selected as control group.All subjects underwent HUTT from October 2000 to November 2019.Get HR (HR0, HR5, HR10) in baseline, HUTT 5 min and 10 min, HRD (HRD5, HRD10) of HR in HUTT 5 min and 10 min minus HR in baseline.Results:(1) HR5, HR10, HRD5, and HRD10 were higher in the POTS group than those in the control group( P<0.05). (2) Univariate Logistic regression: There was a correlation between HR5, HR10, HRD5, HRD10 and the risk of POTS( P<0.01). (3) Multivariable Logistic regression: For each additional unit of HRD5 and HRD10, the risk of POTS increased by 27% ( OR=1.27, 95% CI1.16 to 1.36) and 28% ( OR=1.28, 95% CI1.20 to 1.38). Conclusion:HR and HRD are related with the occurrence of POTS in children and adolescents, but HR and HRD at different time points of HUTT play the little role on the effect size of the occurrence of POTS.

Objective:To study the diagnostic efficacy and prognostic evaluation value of QT interval dispersion (QTd) in children and adolescents with cardioinhibitory vasovagal syncope (VVS-CI).Methods:From July 2010 to January 2020, 80 children and adolescents who received their first visit or admission to the Pediatric Syncope Clinic of The Second Xiangya Hospital of Central South University and definite diagnosed of VVS-CI due to syncope or presyncope were selected as the VVS-CI group, meanwhile, 80 children and adolescents who had physical examination in the hospital were selected as the control group.QT interval were measured by 12-lead electrocardiogram at the baseline.Results:(1) Comparison between the two groups: Compared with the control group, the VVS-CI group had a significantly lower heart rate ( P<0.05) and significantly longer QT interval, such as the maximum QT interval (QTmax), minimum QT interval (QTmin), QTd, corrected maximum QT interval (QTcmax) and corrected QT interval dispersion (QTcd) ( P<0.05). After follow-up 84 (45, 127) days, compared with the responsive group, the non-responsive group had a significantly longer QT interval, such as QTmax, QTd, QTcmax, corrected minimum QT interval (QTcmin)and QTcd ( P<0.05). (2) Diagnostic efficiency: QTmax, QTmin, QTd, QTcmax and QTcd had a certain diagnostic value in children and adolescents with VVS-CI ( P<0.001). QTd had the largest area under the curve (AUC) (0.914), and had a sensitivity of 86.30% and a specificity of 84.95% at the optimal cut-off value of 28.50 ms for VVS-CI diagnosis.(3) Prognostic evaluation value: QTmax, QTd, QTcmax, QTcmin, QTcd had an estimated value for the prognosis of VVS-CI in children and adolescents ( P<0.05 or 0.01). QTd had the largest AUC (0.906) and the best cut-off value was 34.50 ms, the sensitivity to predict response to VVS-CI intervention was 90.00%, and the specificity was 82.35%. Conclusion:QTd of electrocardiogram has a good estimation value in the diagnosis and prognosis of VVS-CI in children and adolescents.