血管迷走性晕厥三种反应类型的心率变异分析

目的对倾斜试验(HUT)中三种不同反应类型的血管迷走性晕厥(VVS)患者进行心率变异分析(HRV)，探讨其不同的发病机制。方法54例不明原因晕厥患者倾斜75度进行持续45min的基础倾斜试验(BHUT)或只到发生晕厥，阴性患者于BHUT结束时恢复到平卧位，含服硝酸甘油0．3mg，然后倾斜75度进行持续20min的硝酸甘油诱导的倾斜试验(NTHUT)或只到发生晕厥，试验过程中进行间隔3min的心率变异分析。结果VVS患者中，血管抑制型(VD)和心脏抑制型(CI)均为8例，阳性率为14．8l％；混合型(MX)10例，阳性率为18．52％。倾斜75度后三组VVS患者的LFn值均增大，HFn值均减小；晕厥前3min时三组VVS的LFn值均升至最高，HFn值降至最低；晕厥时三组VVS患者的LFn值与晕厥前3min相比明显下降，但与倾斜前相比无明显差异；CI和MX组的HFn值与晕厥前3min相比明显增高，与倾斜前相比变化不大，VD组的HFn值与晕厥前3min相比无明显差异；未晕厥组在HUT过程中交感神经活性逐渐增大，试验结束时达到最大，迷走神经活性逐渐减小，试验结束时达到最小。结论VVS的发生与自主神经功能障碍有关，不同类型的VVS患者具有不同的神经调节障碍。

Analysis of heart rate variability in patients with vasovagal syncope of three type

objective To investigate heart rate variability (HRV) of patients with vasavagal syncope (VVS) show 3 different response to head-up tilt test(HUT),which may be due to different pathophysiologycal mechanisms.Methods 54 patients with a history of unexplained syncope were tilted to 75 degrees for 45 min as baseline head-up tilt(BHUT)or until syncope occurred.In those subjects who did not show any symptoms before the end of the 45-min period,returned to supine position,sublingual nitroglycerin(0.3mg)was administered,then tilted to 75 degrees for 20 minutes as nitroglycerin head-up tilt (NTHUT) or until symptoms occurred.HRV was analyzed at 3 min periods during HUT.Results The vasodepressive type (VD)and cardioinhibitory type(CI)of VVS were respectively recongnised in 8 patients(14.81%).10 patients(18.52%)had a mixed response(MX).The normalized low frequency spectrum(LFn)in all patients with VVS increased after tilt,the normalized high frequency spectrum(HFn)decreased.The LFn of all patients with VVS during three minutes before syncope was am greatest,the HFn was am least.The LFn of all patients with VVS during syncope was significantly less than that during three minutes before syncope,but not different to supine position,The HFn of patients with CI and MX during syncope was greater than that during three minutes before syncope,but not different to supine position.The HFn of patients with VD had no difference to three minutes befors syncope.The patients without syncope during HUT showed that sympathetic activity increased and got to the greatest at the end of HUT.The parasympatheetic activity decreased and to the least at the end of HUT.Conclusion VVS is related to dysfunction of automatic-nerven-systm.Different type of VVS had different pathophysiologycal mechanisms.