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目的探讨自主神经调节系统在血管迷走性晕厥(VVS)中的作用。方法复旦大学附属儿科医院2006年4月至2007年3月选择40例临床诊断为VVS的患儿进行HUTT(基础或基础+激发试验),同步监测实验者平卧位、倾斜后1、3、5、10、15、20、25、30、35、40、45min或者晕厥发作时以及恢复平卧位后的血压、心率变化值;利用动态心电图分析系统进行心率变异分析。结果40例HUTT实验组,23例为阳性,心脏抑制型(CI组)2例,血管抑制型(VD组)10例,混合型(MX组)11例,记录平卧位至倾斜位时(T1)、倾斜位全程(T2)与恢复平卧位至实验结束(T3)三点的心率变异指标变化。VD组的LF/HF的值在整个试验过程中(T1-T2-T3)始终是升高的(P=0.002)。T1时两组的RR、SDNN、rMMSD的值差异均无统计学意义。T2时两组的SDNN、rMMSD值均较平卧时降低,阳性组下降更为明显(P=0.015)。至T3时,阴性组的rMMSD值又逐渐升高,与T1相仿,阳性组虽有所升高,但是仍然明显低于T1时(P=0.035)。VD组的SDNN值在倾斜后持续降低并始终<100ms(P=0.023)。结论VVS的血流动力学变化符合Bezold-Jarisch反射的3个阶段,但各亚型间的变化程度不尽相同,提示VVS患者的迷走神经活性较强,心率变异频域指标较时域指标能够更好地反映VVS患者心脏迷走神经张力的改变。
Objective To investigate the role of autonomic nervous system in vasovagal syncope (VVS). Methods From April 2006 to March 2007, 40 children with VVS clinically diagnosed as VVS underwent HUTT (basal or basal + challenge test) from April 2006 to March 2007 in pediatric hospital of Fudan University. The supine position, 5, 10, 15, 20, 25, 30, 35, 40, 45min or the onset of syncope and the recovery of supine position blood pressure and heart rate changes; analysis of heart rate using dynamic electrocardiogram analysis system. Results Forty cases of HUTT group were positive in 23 cases, 2 cases of cardiac arrest (CI group), 10 cases of vascular depression (VD group) and 11 cases of mixed type (MX group) T1), full tilt (T2), and recovery supine position to the end of the experiment (T3) three points of heart rate variability index changes. The values of LF / HF in VD group were consistently elevated throughout the experiment (T1-T2-T3) (P = 0.002). There was no significant difference in the values of RR, SDNN and rMMSD between the two groups at T1. At T2, the values of SDNN and rMMSD in both groups were significantly lower than those in supine group (P = 0.015). At T3, the rMMSD value of the negative group increased gradually again. Similar to T1, the rMMSD value of the negative group was still significantly lower than that of T1 (P = 0.035). SDNN values in VD group continued to decrease after tilting and remained <100ms (P = 0.023). Conclusions The hemodynamic changes of VVS conform to the three stages of Bezold-Jarisch reflex. However, the variation degree of each subtype is not the same, which indicates that the VVS patients have strong vagal activity and the frequency-domain index of heart rate variability can be more than the time domain index Good reflection of VVS patients with changes in cardiac vagal tone.