Objective: To analyze the clinical characteristics and risk factors of malignant vasovagal syncope (VVS) in children. Methods: This was a case-control study. The data of 368 VVS patients who were treated in the Department of Cardiology, Children's Hospital, Capital Institute of Pediatrics from June 2017 to December 2021 was collected and analyzed. They were divided into malignant VVS group and non-malignant VVS group according to the presence of sinus arrest, and then their demographic characteristics were compared. The children with malignant VVS and complete clinical information were recruited into the case group and were matched by age and sex (1∶4 ratio) with non-malignant VVS patients during the same period.Their clinical characteristics and lab tests were compared. Independent sample t test, Mann Whitney U or χ2 test was used for comparison between groups.Logistic regression was used to analyze the risk factors for malignant VVS in children. Results: Eleven malignant VVS and 342 non-malignant VVS met the inclusion and exclusion critera. Eleven malignant VVS and 44 non-malignant children were recruited in the case-control study. Ten patients of the 11 malignant VVS had a cardiac arrest occurring at 35 (28, 35) minutes of the head-up tilt test, and the duration of sinus arrest was (9±5) s. One patient had syncope occurring while waiting for drawing blood, and the duration of sinus arrest was 3.4 s. The children with malignant vasovagal syncope were younger than non-malignant VVS patients (9 (7, 10) vs. 12 (10, 14) years old, P<0.05), and had higher mean corpuscular hemoglobin concentration (MCHC) and standard deviation of the mean cardiac cycle over 5-minute period within 24 hours ((347±9) vs. (340±8) g/L, (124±9) vs. (113±28) ms, both P<0.05). Logistic regression analysis showed that MCHC was an independent risk factor for malignant VVS in pediatric patients (OR=1.13, 95%CI 1.02-1.26, P=0.024). Conclusions: The onset age of malignant VVS was younger, with no other special clinical manifestations. MCHC was an independent risk factor for malignant VVS.
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-Whitney U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）、24 h连续5 min节段平均心动周期均高于对照组，差异均有统计学意义［（347±9）比（340±8）g/L，（124±9）比（113±28）ms，均P<0.05］。Logistic回归分析显示MCHC是VVS患儿发生窦性停搏的独立危险因素（OR=1.13，95%CI 1.02~1.26，P=0.024）。 结论： 恶性VVS患儿发病年龄偏小，临床表现无特殊，MCHC是恶性VVS的独立危险因素。.