摘要
目的:探究血管迷走性晕厥(VVS)患者在直立倾斜试验中自主神经活性的变化。方法:53例不明原因、反复发作晕厥的患者,排除器质性疾病和代谢性疾病引起的晕厥后行直立倾斜试验,观察有无阳性反应。倾斜过程中记录动态心电图、血压和心率,并分析心率变异性频域指标:低频标准化值(LFnorm)、高频标准化值(HFnorm)和低高频比值(LF/HF),以及QT动态性指标:QTe/RR斜率和QTp/RR斜率。结果:53例患者均行硝酸甘油激发的倾斜试验,其中23例结果阳性,心脏抑制型1例,占4.3%,血管抑制型6例,占26.1%,混合型16例,占69.6%。在硝酸甘油激发的试验阶段,阳性组LFnorm显著低于基础试验阶段(P<0.05),HFnorm呈上升趋势;而阴性组与基础试验阶段相比,LFnorm、HFnorm及LF/HF均无显著变化(P>0.05)。在服用硝酸甘油后,阴性组的QTe/RR斜率、QTp/RR斜率较之前均显著升高(P<0.05),而阳性组无显著差异。将阴性组以50岁为界,按年龄分为两个亚组,50岁以上组在服用硝酸甘油前、后的心率变异性HF、LF/HF有显著差异(P<0.05),而50岁以下组无明显变化。结论:直立倾斜试验中,交感神经兴奋占主导突然转变为迷走神经过度兴奋是VVS发生的重要机制。心率变异性频域指标和QT动态性指标对于VVS的辅助诊断可能具有一定的参考价值。
Objective:To investigate autonomic nervous activity changes during head-up tilt table test in patients with vasovagal syncope(VVS).Methods:Fifty-three patients with recurrent syncope with unknown reasons were enrolled.Head-up tilt table tests(HUTTT)were performed after organic diseases and metabolic diseases were excluded.Patients were tilted upright to 75°headup and observed for 30 minutes.If the basic testing result was negative,sublingual nitroglycerin(0.3 mg)was administered after 10 minutes lying flat and tilted for another 15 minutes.Dynamic electrocardiogram,blood pressure and heart rate were recorded throughout the procedures.Heart rate variability(HRV)power spectral including LFnorm,HFnorm and LF/HF and QT dynamics including QTe/RR and QTp/RR were analyzed.Results:All fifty-three patients underwent nitro-glycerin-induced head-up tilt table test and 23 were positive with 1 cardioinhibitory response(4.3% ),6 vasodepressive response(26.1% )and 16 mixed response(69.6% ).LFnorm significantly(P<0.05)decreased after nitroglycerin was administered and HFnorm showed increased tendency in the HUTTT positive group.While in the negative group,LFnorm,HFnorm,and LF/HF did not changed markedly.After nitroglycerin was administered,QTe/RR and QTp/RR were both significantly increased(P<0.05)while there were no such changes in the positive group.When the negative group divided according to age into two groups representing young(16-50 years,n=16)and elderly(51-68 years,n=14)subjects,the decrease in HF power and the increase in LF/HF ratio were significantly smaller in the elderly subjects compared with the young subjects in response to HUT.Conclusion:The abrupt transition of dominance of autonomic nervous activity from sympathetic activity to vagal activity account for the underlying mechanism of VVS.HRV power spectral and QT dynamic indices might be helpful for the diagnosis of VVS.
出处
《武汉大学学报（医学版）》
CAS
2018年第1期109-113,共5页
Medical Journal of Wuhan University
基金
湖北省自然科学基金资助项目(编号:2013CFA117)
中央高校基本科研业务费专项资金项目(编号:2042014kf0306)
