不明原因晕厥儿童血流动力学反应类型与临床表型的关系

目的探讨不明原因晕厥儿童在直立倾斜试验中不同血流动力学类型及其分布,研究不同血流动力学类型与其临床表型之间的关联。方法对100例不明原因晕厥儿童均进行直立倾斜试验(HUT)或舌下含化硝酸甘油激发直立倾斜试验,并根据其在实验中不同的血流动力学反应分为血管迷走性反应型、体位性心动过速综合征反应型、体位性低血压反应型及正常血流动力学反应型4种类型,研究其分布及比较其临床特征。结果100例不明原因晕厥患儿HUT中,50例(50%)出现经典的血管迷走性反应型,33例出现体位性心动过速综合征反应型(33%),15例出现正常反应型(15%),2例出现体位性低血压反应型(2%)。其中在50例血管迷走性反应型中,31例为血管抑制型(31%),12例为混合型(12%),7例为心脏抑制型(7%)。血管迷走性反应型及体位性心动过速反应型的患儿平均年龄大于正常血流动力学反应型的患儿(12±2vs10±3,P<0·01;12±2vs10±3,P<0·01);各种血流动力学类型之间男女性别比没有显著性差异;各种血流动力学类型之间病程的比较亦没有显著性差异;体位性心动过速综合征反应型患儿的晕厥次数显著少于血管迷走性反应型及正常反应型患儿(1±1vs3±3,P<0·01,1±1vs3±2,P<0·01);体位性心动过速综合征反应型基础心率显著快于血管迷走性反应型及正常反应型患儿(81±7vs71±9,P<0·01,81±7vs74±7,P<0·01);基础血压在各种血流动力学类型之间比较都没有显著性差异。发病年龄、性别、病程长短、晕厥次数、基础心率及基础收缩压和舒张压,在血管迷走性反应各亚型之间相比较均无显著性差异。结论不明原因晕厥儿童在直立倾斜试验中可表现出不同的血流动力学反应类型,不同的血流动力学类型之间与其临床表型有一定的关联。

Association of clinical features with different hemodynamic patterns in head-up tilt test in children with unexplained syncope

OBJECTIVE: To explore the different hemodynamic patterns during the course of head-up tilt tests in children with unexplained syncope and the association of clinical features with different hemodynamic patterns in head-up tilt test in children with unexplained syncope. METHODS: 100 pediatric patients with unexplained syncope, aged 11 +/- 2 (6-16), 36 male and 64 female, with the mean course of 10 +/- 16 months (2 d-5 y), underwent head-up tilt tests or head-up tilt tests potentiated with nitroglycerine under quiet circumstance. Blood pressure and heart rate were monitored simultaneously. According to their different hemodynamic patterns, they were divided into vasovagal response pattern, postural orthostatic tachycardia syndrome (POTS) response pattern, orthostatic hypotension (OH) response pattern and normal response pattern. The vasovagal response was divided into vasodepressor, cardioinhibitory and mixed patterns. The distribution and different clinical features of different response patterns in the unexplained syncope were also studied. RESULTS: Fifty (50%) of the 100 children with unexplained syncope displayed the hemodynamic pattern of vasovagal response, among which 31 (31%) displayed the pattern of vasodepressor response, 7 (7%) cardioinhibitory response, and 12 (12%) mixed response. Thirty-three patients (33%) displayed POTS response, 2 (2%) OH response, and 15 (15%) the normal hemodynamic response. Patterns of dysautonomic response and chronotropic incompetence were not observed in these children with unexplained syncope. The age of the children with normal response during HUT was 10 +/- 3 years, significantly younger than that of the children with vasovagal response and POTS response (12 +/- 2 and 12 +/- 2, both P < 0.01). There were no differences in sex ratio and duration of syncope among the vasovagal response, POTS and normal response. But the syncopal spells in the children with POTS response was less frequent and the baseline heart rate of the children with POTS response was 81 +/- 7, significantly faster than that of the children with vasovagal response and normal response (71 +/- 9 and 74 +/- 7, both P < 0.01). There was no significant difference in the baseline blood pressure among the children with vasovagal response, POTS and normal response. There were also no significant differences in the age, sex ratio, and duration of syncope, number of syncopal spells, baseline heart rate, and baseline blood pressure among the children with vasodepressor response, cardioinhibitory response and mixed response. CONCLUSION: There are different hemodynamic response patterns in head-up tilt testing in children with unexplained syncope, and there was some association between hemodynamic response patterns and their clinical features.