目的：探讨儿童体位性心动过速综合征（POTS）合并血管迷走性晕厥（VVS）的诊断。方法：回顾性地复习2007年1月至2010年12月经直立倾斜试验（HUT）诊断为POTS的57例儿童的临床资料，其中男29例，女28例，年龄5～16(12.2±1.9)岁。结果：57例POTS儿童中，在可以耐受倾斜体位的前提下，通过延长HUT时间，24例(42%)经HUT诊断合并VVS，其中血管抑制型20例，混合型3例，心脏抑制型1例。合并VVS儿童平均年龄（13.0±1.4岁）大于未合并VVS的POTS儿童（11.5±2.1岁），差异有统计学意义（P0.05）。结论：部分POTS儿童合并VVS，在可以耐受倾斜体位的前提下，延长HUT时间有利于防止VVS漏诊。与未合并VVS的POTS儿童比较，合并VVS儿童年龄较大，但性别、临床症状无明显差异。

OBJECTIVE: To study the diagnosis of vasovagal syncope (VVS) in children with postural orthostatic tachycardia syndrome (POTS). METHODS: The clinical data of 57 children with POTS diagnosed by the head-up tilt test between January 2007 and December 2010 were studied retrospectively. Of the 57 children, there were 29 boys and 28 girls who were aged from 5 to 16 years (12.2±1.9 years). RESULTS: Twenty-four (42%) out of 57 children were diagnosed with VVS by prolonging the duration of the head-up tilt test (for the children with orthostatic tolerance): cardioinhibitory (20 cases), mixed (3 cases) and vasoinhibitory (1 case). The POTS children with VVS were older than those without (13.0±1.4 years vs 11.5±2.1 years; P<0.05). There were no significant differences in gender and clinical symptoms between the POTS children with and without VVS. CONCLUSIONS: Some children with POTS may have coexisting VVS, suggesting that it is important to avoid misdiagnosis of VVS by prolonging the duration of head-up tilt test in POTS children with orthostatic tolerance. There are no obvious differences in gender and clinical symptoms between the POTS children with and without VVS.