Department of Cardiovascular Dysautonomia, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico.
Department of Electromechanical Instrumentation, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico.
Rev Invest Clin. 2021 Nov 5;73(6). doi: 10.24875/RIC.21000199.
Cerebral hypoperfusion before syncope has been shown in patients with chronic orthostatic intolerance (OI) without tachycardia, but it is unknown if an initial decrease of cerebral blood flow velocity (CBFv) could be related to the vasovagal response (VVR) to head-up tilt test (HUTT).
The objective of the study was to compare cardiovascular, cerebrovascular, and autonomic variables during HUTT in OI patients with or without a VVR.
We included 74 subjects (58% female, mean age 33 ± 12 years) who underwent a 30-min HUTT and were divided into three groups: OI with VVR positive (VVR+), OI without VVR negative (VVR-), and asymptomatic healthy subjects with negative HUTT (control group). Cardiovascular, cerebrovascular, and autonomic variables were assessed beat-to-beat during HUTT with a Task Force monitor and a trans-cranial Doppler. Mean values were evaluated at baseline and throughout the first 10 min of tilting.
Cardiovascular variables were similar in the three groups. Systolic, diastolic, and mean CBFv were similar in VVR+ and VVR-, but both groups had lower CBFv than the control group. Systolic and diastolic CBFv decreased from baseline since min 1 in VVR+ and VVR- and since min 5 in the control group. The mean CBFv had a significant decrease since min 1 compared to baseline in all groups. Spectral indices of heart rate and blood pressure variability showed a similar autonomic response to HUTT in all groups.
Patients with chronic OI without tachycardia have early postural cerebral hypoperfusion, regardless of the VVR during HUTT.
在没有心动过速的慢性体位不耐受（OI）患者中，已经观察到晕厥前的脑灌注不足，但尚不清楚初始脑血流速度（CBFv）的下降是否与直立倾斜试验（HUTT）中的血管迷走性反应（VVR）有关。
本研究的目的是比较 OI 患者伴有或不伴有 VVR 时 HUTT 期间的心血管、脑血管和自主神经变量。
我们纳入了 74 名受试者（58%为女性，平均年龄 33±12 岁），他们接受了 30 分钟的 HUTT，并分为三组：伴有 VVR 阳性的 OI（VVR+）、伴有 VVR 阴性的 OI（VVR-）和 HUTT 阴性的无症状健康对照者（对照组）。使用 Task Force 监测仪和经颅多普勒超声仪逐搏评估 HUTT 期间的心血管、脑血管和自主神经变量。在基线和倾斜的前 10 分钟内评估平均值。
三组的心血管变量相似。VVR+和 VVR-的收缩压、舒张压和平均 CBFv 相似，但两组的 CBFv均低于对照组。从第 1 分钟开始，VVR+和 VVR-的收缩压和舒张压以及对照组的 CBFv均从基线开始下降。与基线相比，所有组的平均 CBFv 在第 1 分钟开始时均有显著下降。心率和血压变异性的频谱指数在所有组中均显示出对 HUTT 的相似自主神经反应。
无论 HUTT 期间是否存在 VVR，无心动过速的慢性 OI 患者均存在早期体位性脑灌注不足。
