Zygmunt Agnieszka, Stanczyk Jerzy
Pediatric Cardiology Dept., Institute of Pediatrics, Medical University of Lodz, Lodz 90-243, Poland.
Clin Auton Res. 2004 Apr;14(2):99-106. doi: 10.1007/s10286-004-0168-0.
In order to characterize the autonomic profile of syncopal children, we have studied heart rate variability (HRV) of 73 children, ages 11-18, with neurocardiogenic syncope and a positive outcome of head-up tilt testing (HUT).HRV was calculated over a 24-hour period for the time-domain indices (SDNN, SDANNi, SDNN, rMSSD, pNN50), and over 5-minute segments from night and day for frequency-domain indices (LF, HF, LF/HF). The obtained results were compared to reference values calculated for Polish children. 55% of the children had mixed response to HUT, 41% vasodepressor and 4% cardioinhibitory. Patients with syncope had significantly lower values of rMSSD and pNN50 in comparison to healthy children. Moreover, in the frequency-domain analysis they exhibited significantly higher LF and lower HF values. The day-night rhythm of HRV and the age-related changes of HRV were, however, similar in syncopal and healthy children. In addition to this, we found a significantly lower SDNN value in children with cardioinhibitory response during HUT in comparison to children with mixed response. We concluded that 1) based on HRV analysis children with neurocardiogenic syncope had alterations in basal autonomic balance, which indicated an increased sympathetic modulation in these patients, 2) syncopal children had adequate circadian rhythm of autonomic activity, 3) the changes of HRV indices with age in these groups are not altered in comparison to healthy children, 4) syncopal children may exhibit differences in HRV indices values depending on the kind of vasovagal response observed during HUT.
为了描述晕厥儿童的自主神经特征，我们研究了73名年龄在11至18岁之间、患有神经心源性晕厥且直立倾斜试验（HUT）结果为阳性的儿童的心率变异性（HRV）。HRV的时域指标（SDNN、SDANNi、SDNN、rMSSD、pNN50）是在24小时内计算得出的，频域指标（LF、HF、LF/HF）则是在夜间和白天的5分钟时间段内计算得出的。将所得结果与为波兰儿童计算的参考值进行比较。55%的儿童对HUT有混合反应，41%为血管减压型，4%为心脏抑制型。与健康儿童相比，晕厥患者的rMSSD和pNN50值显著较低。此外，在频域分析中，他们的LF值显著较高，HF值较低。然而，晕厥儿童和健康儿童的HRV昼夜节律以及HRV随年龄的变化相似。除此之外，我们发现与混合反应的儿童相比，HUT期间有心脏抑制反应的儿童的SDNN值显著较低。我们得出以下结论：1）基于HRV分析，神经心源性晕厥儿童的基础自主神经平衡发生改变，这表明这些患者的交感神经调节增强；2）晕厥儿童具有适当的自主神经活动昼夜节律；3）与健康儿童相比，这些组中HRV指标随年龄的变化未改变；4）根据HUT期间观察到的血管迷走反应类型，晕厥儿童的HRV指标值可能存在差异。
