血管抑制型血管迷走性晕厥患者异丙肾上腺素倾斜试验中的血流动力学特点

目的了解血管抑制型(VD)血管迷走性晕厥(VVS)患者在异丙肾上腺素(ISO)药物直立倾斜试验(IHUT)中的血流动力学改变,并对观察指标的敏感性进行探讨。方法15例IHUT阳性的VD型VVS患者(VVS组)及15名健康志愿者(对照组)进行了基础直立倾斜试验(BHUT)及单阶段异丙肾上腺素直立倾斜试验(SIHUT),在此过程中采用BioZ.com数字化无创血流动力学监测仪持续观察,对入选指标心率(HR)、血压(BP)、心排量(CO)、心脏指数(CI)、心缩加速度指数(ACI)、体循环血管阻力(SVR)及胸部含液量的基础阻抗(TFC)进行分析。结果在BHUT时,两组均出现TFC值明显下降。在ISO注入仍仰卧位时,VVS组SVR值就显著下降,同时HR、CO、CI及ACI值明显升高;对照组SVR值无明显变化,但HR及ACI值也明显升高。在SIHUT阶段并且VVS组未发生晕厥时,两组仅HR值明显升高。VVS组发生先兆晕厥或晕厥时,其HR、BP及SVR值显著下降,CO、CI及ACI值仍持续明显升高。结论在IHUT过程中,VD型VVS患者血流动力学异常。其晕厥发生主要与体循环血管阻力大幅度下降及ISO的诱导作用有关,并提示本组患者存在β2受体过敏。SVR值是诊断对ISO敏感或依赖的血管抑制型血管迷走性晕厥的早期指标。

Hemodynamic changes in vasodepressive vasovagal syncope cases during a single-stage isoprenaline head-up tilt-table test

Objective The aim of this study is to investigate the hemodynamic changes in patients with vasodepressive vasovagal syncope(VVS) during a single-stage isoprenaline head-up tilt-table test(SIHUT).Methods Fifteen patients with vasodepressive vasovagal syncope and positive result during SIHUT(VVS group),15 healthy volunteers with nonsyncope and negative result during SIHUT(control group) underwent noninvasive hemodynamic observation.During SIHUT the BioZ.com digital noninvasive hemodynamic instrument was utilized simultaneously.16 hemodynamic parameters could be recorded at the same time,of them seven were analyzed.Cardiomoto including HR,CO(cardiac output),CI(cardiac index),and ACI(acceleration index);afterload including BP and SVR(systemic vascular resistance),preload was similar to TFC(thoracic fluid content:the inverse of the thoracic base impedance).TFC value responded mainly the fluid change in heart and large blood vessel;it included preload.Results In BHUT,TFC values were decreased significantly in two groups.Maybe,it illustrated the reduced end-diastolic volume.In isoprenaline infusion and supine position,the VVS group showed SVR value decreased significantly;conversely,HR,CO,CI and ACI values increased significantly.During presyncope and syncope,the SVR,BP and HR values decreased significantly;conversely,CO,CI and ACI values increased significantly in VVS group.However,TFC value did not decrease significantly.Conclusion The study revealed there was an abnormal hemodynamic change in VVS group;the onset of syncope is mainly related to a big drop in systemic vascular resistance(SVR) and isoprenaline′s induction;patients in this trial had some receptor-β_2 hypersensitivity;SVR value can become an early index for diagnosing the isoprenaline-sensitized and isoprenaline-dependent vasodepressive vasovagal syncope.