Reduced compensatory responses to maintain central blood volume during hypovolemic stress in women with vasovagal syncope

Author:

Skoog Johan1,Zachrisson Helene12,Länne Toste13,Lindenberger Marcus14

Affiliation:

1. Department of Medical and Health Sciences, Linköping University, Linköping, Sweden;

2. Department of Clinical Physiology, Linköping University, Linköping, Sweden;

3. Department of Thoracic and Vascular Surgery, Linköping University, Linköping, Sweden; and

4. Department of Cardiology, Linköping University, Linköping, Sweden

Abstract

Although vasovagal syncope (VVS) is a common clinical condition, the underlying pathophysiology is not fully understood. A decrease in cardiac output has recently been suggested as a factor in orthostatic VVS. The aim was to investigate compensatory mechanisms to maintain central blood volume and venous return during hypovolemic stress in women with VVS. Fourteen VVS women (25.7 ± 5.0 yr) and 15 matched controls (22.8 ± 3.2 yr) were investigated. Single-step and graded lower body negative pressure (LBNP) to presyncope were used to create hypovolemic stress. Peripheral mobilization of venous blood from the arm (capacitance response and net capillary fluid absorption) and lower limb blood pooling (calf capacitance response) were evaluated using a volumetric technique. Cardiovascular responses and plasma norepinephrine (P-NE) were measured. Resting P-NE was elevated in VVS women ( P < 0.01). Despite a similar hypovolemic stimulus, the increase in P-NE was blunted ( P < 0.01) and the maximal percent increase in total peripheral resistance was reduced ( P < 0.05) during graded LBNP in VVS women. The arm capacitance response was slower ( P < 0.05) and reduced in VVS women at higher levels of LBNP ( P < 0.05). Capillary fluid absorption from extra- to intravascular space was reduced by ∼40% in VVS women ( P < 0.05). Accordingly, the reduction in cardiac output was more pronounced ( P < 0.05). In conclusion, in VVS women, mobilization of peripheral venous blood and net fluid absorption from tissue to blood during hypovolemic stress were decreased partly as a result of an attenuated vasoconstrictor response. This may seriously impede maintenance of cardiac output during hypovolemic stress and could contribute to the pathogenesis of VVS.

Funder

The Heart and Lung Foundation

Futurum the Academy of Health Care, Jonkoping Couty Council

Medical Research Council of Southeast Sweden

Publisher

American Physiological Society

Subject

Physiology (medical),Physiology

Cited by 6 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3