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目的分析血管迷走性晕厥(VVS)患儿无症状期间的心率变异。方法选择本院45例临床诊断VVS的患儿为研究组,其中直立倾斜试验(HUTT)阳性者38例、阴性7例;匹配20例健康儿童为健康对照组。分析2组24 h心率变异时域及频域指标的变化。结果 1.研究组与健康对照组比较:时域指标SDNN(R-R间期)(121.82±33.0 vs 152.95±31.66,P<0.01)、SDANN(24 h内5 min节段平均心动周期的标准差)(114.42±33.41 vs 134.7±27.43,P<0.05)明显下降;频域指标低频功率/高频功率(LF/HF)(1.67±0.54 vs 1.25±0.20,P<0.01)明显升高。2.HUTT阳性组与阴性组时域及频域指标比较无明显差异(P>0.05)。3.血管抑制型(VD)与心脏抑制型(CI)患儿比较,SDNN(100.61±23.02 vs 150.5±29.46,P<0.01)、SDANN(96.78±28.77 vs 141.25±29.06,P<0.05)、rMSSD(相邻正常R-R间期差值的均值)(29.22±19.56 vs 53.75±23.08,P<0.05)、PNN50(全部NN间期中相邻的NN间期之差>50 ms的心搏数占所有NN间期个数的百分数)(11.29±9.31 vs 23.96±12.54,P<0.05)明显下降;LF(39.61±8.45 vs 19.68±4.17,P<0.01)、LF/HF(2.12±0.55 vs 1.09±0.11,P<0.01)明显升高。与混合型(MX)比较,VD患儿rMSSD(29.22±19.56 vs 52.57±18.54,P<0.05)、PNN50(11.29±9.31 vs 22.96±11.13,P<0.05)明显下降;LF(39.61±8.45 vs 29.72±9.87,P<0.05)、LF/HF(2.12±0.55 vs 1.38±0.30,P<0.01)则明显升高。CI型与MX型比较各指标之间无显著差异(P>0.05)。4.VD患儿与健康对照组比较:rMSSD(29.22±19.56 vs 49.55±14.10,P<0.05)、PNN50(11.29±9.31 vs 21.3±9.82,P<0.05)明显下降,LF(39.61±8.45 vs 25.49±5.03,P<0.05)显著升高。结论 VVS患儿无症状期间自主神经功能存在变化;rMSSD、PNN50及LF对预测VD型VVS可能具有参考价值。
Objective To analyze the heart rate variability during asymptomatic children with vasovagal syncope (VVS). Methods Forty-five children with VVS diagnosed in our hospital were selected as the study group. Among them, 38 were positive for HUTT and 7 were negative for VUT, and 20 healthy children were matched as healthy controls. The changes of 24 h heart rate variability in both time and frequency domains were analyzed. Results 1. Compared with healthy control group, the time domain index SDNN (RR interval) (121.82 ± 33.0 vs 152.95 ± 31.66, P <0.01), SDANN (standard deviation of mean cardiac cycle within 5 min within 24 h) (114.42 ± 33.41 vs 134.7 ± 27.43, P <0.05). The LF / HF power (LF / HF) was significantly higher in HF group (1.67 ± 0.54 vs 1.25 ± 0.20, P <0.01). There was no significant difference in the time domain and frequency domain between HUTT positive group and negative group (P> 0.05). SDNN (100.61 ± 23.02 vs 150.5 ± 29.46, P <0.01), SDANN (96.78 ± 28.77 vs 141.25 ± 29.06, P <0.05), and rMSSD in children with angiostatic (VD) and cardiac inhibition (29.22 ± 19.56 vs 53.75 ± 23.08, P <0.05), PNN50 (the difference between adjacent NNs in all NNs> 50 ms accounted for all NNs LF (2.12 ± 0.55 vs 1.09 ± 0.11, P <0.01), and the percentage of interphase was significantly higher in LF / HF group (11.29 ± 9.31 vs 23.96 ± 12.54, P < P <0.01) was significantly higher. Compared with mixed type (MX), the rMSSD of VD children (29.22 ± 19.56 vs 52.57 ± 18.54, P <0.05), PNN50 (11.29 ± 9.31 vs 22.96 ± 11.13, P <0.05) decreased significantly; LF (39.61 ± 8.45 vs 29.72 ± 9.87, P <0.05). LF / HF (2.12 ± 0.55 vs 1.38 ± 0.30, P <0.01) increased significantly. There was no significant difference between each index of CI and MX (P> 0.05). Compared with healthy control group, there was a significant decrease of PNN50 (11.29 ± 9.31 vs 21.3 ± 9.82, P <0.05) in children with VD compared with healthy control group, rMSSD (29.22 ± 19.56 vs 49.55 ± 14.10, P <0.05) ± 5.03, P <0.05). Conclusions The changes of autonomic nervous function in children with VVS during asymptomatic period may be different. The rMSSD, PNN50 and LF may be valuable for predicting VVS in VD.