不同亚型血管迷走性晕厥患者倾斜试验中的自主神经变化及血流动力学反应

观察不同亚型血管迷走性晕厥 (VVS)患者倾斜试验中的自主神经变化及血流动力学反应。 5 5例不明原因晕厥患者及 2 0例健康人行直立倾斜试验。基础试验阴性者 ,行硝酸甘油激发试验。倾斜试验过程中连续监测心电图、血压和心率 ,并进行心率变异性分析。结果 :病例组 5 5人中 32人出现阳性反应。心脏抑制型患者晕厥前心率为 10 8± 2 0 .4 1次 /分 ,晕厥时急剧下降至 4 6 .5± 5 .74次 /分 ,下降比率为 5 6 .32 %± 6 .4 8%。血管抑制型患者晕厥时与晕厥前相比 ,收缩压、舒张压和平均动脉压的下降比率分别为 33.31%± 10 .16 %、31.0 5 %± 10 .96 %和 30 .81%± 9.11%。混合型患者晕厥前心率为 119± 7.38次 /分 ,晕厥时下降至 4 8.4 0± 11.89次 /分 ,下降比率为 5 9.12 %± 10 .4 1%,收缩压、舒张压和平均动脉压的下降比率分别为 31.13%± 13.2 7%、33.0 8%± 14 .33%和 31.5 6 %± 12 .77%。各型VVS患者晕厥前功率谱均显示低频段功率的标化值 (LFnorm)及低频与高频功率的比值 (LF/HF)显著增加 ,高频段功率的标化值 (HFnorm)显著下降 ;而晕厥时LFnorm及LF/HF显著下降 ,HFnorm显著增加。结论 :自主神经功能改变是各型VVS患者发生晕厥的共同机制 ,但可产生不同的血流动力学反应。

Changes of Autonomic Nerve Function and Hemodynamic Patterns in Patients With Vasovagal Syncope During Tilt-Table Testing

This study is to investigate the changes of autonomic nerve function and various responses in hemodynamics in patients with vasovagal syncope during tilt-table testing (TTT). TTT was performed in fifty-five subjects with unexplained syncope and twenty healthy subjects as control group. If the subject had a negative response in basic TTT, sublingual nitroglycerin (0.3mg) was administered . Heart rate,blood pressure and heart rate variability (HRV) of each subject were continuously analyzed during TTT. Results: 32 of 55 subjects with history of unexplained syncope had a syncope during TTT. In the subjects with cardioinhibitory response, heart rate before immediate syncope was 108±20.41bpm and abruptly decreased by 46.5±5.74 bpm (decreased percentage by 56.32%±6.48%) when syncope occurred. In the subjects with vasodepressive response, systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean artery pressure (MAP) abruptly decreased at syncope, with decreased percentage by 33.31%±10.16%, 31.05%±10.96% and 30.81%±9.11%, respectively. For the subjects with mixed response, heart rate abruptly decreased from 119±7.38 bpm to 48.40±11.89 bpm (decreased percentage by 59.12%±10.41%) at syncope; meanwhile SBP, DBP and MAP abruptly decreased, with decreased percentage by 31.13%±13.27%, 33.08%±14.33% and 31.56%±12.77%, respectively. For all the subjects with positive response, the HRV data showed that LFnorm and LF/HF markedly increased whereas HFnorm decreased before immediate syncope. When syncope occurred, LFnorm and LF/HF markedly decreased whereas HFnorm increased. Conclusion: The changes of autonomic nervous function may lead to various patterns of vasovagal syncope, with different responses in hemodynamics.